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April 22, 2020
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https://www.sciencedaily.com/releases/2020/04/200422112241.htm
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Specialized nerve cells increase the appetite for high-fat foods
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High-calorie, energy-dense foods are constantly available in our modern society. Researchers at the Max Planck Institute for Metabolism Research in Cologne have discovered that a group of nerve cells in the brains of mice promotes the consumption of high-fat food. If these so-called nociceptin neurons in the hypothalamus are activated, the animals start to eat more.
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Since the 1980s, we are seeing a worldwide increase in obesity and associated diseases such as diabetes mellitus and cardiovascular disease. Researchers from the Max Planck Institute for Metabolism Research from the laboratory of Jens Brüning have used mice in animal studies to investigate which nerve cells control the overeating of high-calorie, energy dense food. For this purpose, the animals were fed a high-fat diet and examined afterwards." Just three days of a high-fat diet feeding were sufficient to detect increased activity of nociceptin neurons in a specific region of the brain, the arcuate nucleus of the hypothalamus," says Alexander Jais, first author of the current study.In a set of experiments, nociceptin neurons of mice were selectively removed from the arcuate nucleus of the hypothalamus. As a result, these mice no longer "over-consumed" the high-fat diet. The intake of their normal food was not affected. The nociceptin neurons can therefore specifically control the intake of high-fat food.Following up these findings, the researchers used genetically modified mice in which the activity of the nociceptin neurons in the hypothalamus could be controlled by light. "The activation of these brain cells led to an excessive food intake of the animals," Jais explains. "The activation of nociceptin neurons inhibits certain neurons which regulate satiety and therefore the animals ingest more food."Consumption of energy-dense food leads to a disruption of energy balance and to an increased intake of calories. "We are constantly surrounded by cheap, palatable, energy-dense foods and our brains are wired in such a way that we particularly prefer these foods," says Jais. "It is still not known why some people manage to eat only as much as they need and others do not. The individual activity of nociceptin neurons could be an important piece to the puzzle. Their activity promotes overconsumption, making them an attractive target for the prevention and treatment of obesity.""The current Covid-19 pandemic reminds us that obesity and associated metabolic diseases, such as diabetes, are risk factors and therefore a better understanding of the central nervous system control of food intake is urgently needed, with particular emphasis on high-calorie, fat- and carbohydrate-rich foods," says Jais.
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April 22, 2020
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https://www.sciencedaily.com/releases/2020/04/200422091212.htm
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At least four new species of African leaf-nosed bats discovered
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Bats play a huge but poorly understood role in humans' lives -- they pollinate our crops, eat disease-carrying mosquitos, and carry diseases themselves. But we know next to nothing about most of these animals. There are more than 1,400 species of bats, and 25% of them have only been recognized by scientists in the last 15 years. For most bats, we don't really know how they evolved, where they live, and how they interact with the world around them. That lack of knowledge can be dangerous -- the more we know about bats, the better able we are to protect them and defend ourselves against diseases that they can spread.
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In a new paper in a special issue of the journal "With COVID-19, we have a virus that's running amok in the human population. It originated in a horseshoe bat in China. There are 25 or 30 species of horseshoe bats in China, and no one can determine which one was involved. We owe it to ourselves to learn more about them and their relatives," says Bruce Patterson, the Field Museum's MacArthur curator of mammals and the paper's lead author."None of these leaf-nosed bats carry a disease that's problematic today, but we don't know that that's always going to be the case. And we don't even know the number of species that exist," says Terry Demos, a post-doctoral researcher in Patterson's lab and a principal author of the paper.The bats that Patterson and Demos studied are leaf-nosed bats in the family Hipposideridae. They get their common name from the elaborate flaps on skin on their noses that the bats use as radar dishes to focus their calls and help catch their insect prey. The family is spread throughout Africa, Asia, and Australasia but its African members are poorly known to science due to lack of research and political unrest in the areas where they're found.To get a better understanding of how the leaf-nosed bats are distributed and how they're related to each other, Patterson, Demos, and their colleagues at Kenya's Maasai Mara University and the National Museums of Kenya, and the Field Museum undertook a genetic study of leaf-nosed bats in Africa almost entirely based on museum specimens collected in various parts of Africa over the last few decades. In several cases, supposedly widespread species proved to be several genetically distinct species that simply looked alike -- new species hidden in plain sight. These "cryptic species" often look similar to established species, but their DNA hints at their distinct evolutionary histories.The genetic research indicates at least four new and undescribed species of bats; these new species don't have official names yet, but they give us a glimpse at how much we still have to learn about Africa's bats.Finding new species of animals is always cool, but Patterson and Demos say this discovery takes on special importance in the era of COVID-19. The new species of leaf-nosed bats didn't play a role in the coronavirus pandemic, but their sister family of horseshoe bats did. The horseshoe bats transmitted the novel coronavirus to another mammals (possibly the endangered, scale-covered pangolins), which then spread the disease to humans. It's not the first time humans have contracted a disease from bats -- they seem more capable of transmission than most other mammals.It's not that bats are uniquely dirty or covered in viruses. "All organisms have viruses. The roses in your garden have viruses," says Patterson. "We worry about viruses when it comes to flu and pandemics, but viruses are part of nature and have been as far back as we go. And many viruses are harmless." But while all animals carry viruses, bats seem especially good at passing them on to us. It might be because bats are some of the most social mammals, living in colonies of up to 20 million. "Because they huddle together and take care of each other, it doesn't take long for a pathogen to get passed from one end of the colony to the other," says Patterson.The other possible reasons for bats being prone to spread disease can be traced to their ability to fly. "Flying is the most energetically expensive way to get around. If you skin a bat, it looks like Mighty Mouse, they have hardly any guts, they're all shoulders and chest muscle. They're incredible athletes," says Patterson. And since flying is such hard work, they have high metabolisms and strong immune systems, and their DNA is really good at repairing itself when damaged. This extra hardiness means bats can harbor disease-causing agents without getting sick themselves; that same dose can be harmful to humans who come into contact with the bats.And while these bats don't normally have much contact with humans, the more that people destroy bats' habitats and expose themselves to bats through hunting and consuming bat meat, the more likely it is that bats will spread viruses to people. "Unless you try to seek out bats, either to harass them or kill them, it's very, very unlikely that they'll infect you," says Demos.The researchers also note that while horseshoe bats, not their leaf-nosed cousins studied in this paper, have been tied to the spread of COVID-19, it's still important to study leaf-nosed bats to help prevent future outbreaks. "Leaf-nosed bats carry coronaviruses -- not the strain that's affecting humans right now, but this is certainly not the last time a virus will be transmitted from a wild mammal to humans," says Demos. "If we have better knowledge of what these bats are, we'll be better prepared if that happens."The researchers also emphasize that in addition to questions about how the bats could harm humans, we need to make sure that we humans don't harm bats in hopes of curbing disease. Patterson notes, "These bats have a place in nature and perform essential ecological functions, and we can't let our terror of COVID cause us to pull apart natural ecological systems."
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Animals
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April 22, 2020
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https://www.sciencedaily.com/releases/2020/04/200422091140.htm
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Surface feeding could provide more than just snacks for New Zealand blue whales
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Feeding at the ocean's surface appears to play an important role in New Zealand blue whales' foraging strategy, allowing them to optimize their energy use, Oregon State University researchers suggest in a new study.
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Blue whales are the largest mammals on Earth. Because of their enormous size, the whales must carefully balance the energy gained through their food intake with the energetic costs of feeding, such as diving, holding their breath or opening their mouths, which slows their movement in the water. Adding to the challenge: their prey are tiny krill and they must find and eat large volumes of them to make any energetic headway."People think about whales having to dive deep to get to the densest prey patches, but if they can find their prey in shallow waters, it's actually more energetically profitable to feed near the surface," said Leigh Torres, an assistant professor and director of the Geospatial Ecology of Marine Megafauna Laboratory at OSU's Marine Mammal Institute. "In this population of whales in New Zealand, they foraged more in areas where their prey was dense and shallow."Their dives were relatively short, and they were feeding more at the surface, which requires less energy."The findings were published today in the journal Much of what researchers know about blue whale foraging comes from tags placed on whales, which can record travel and diving patterns, including acceleration, or lunging, toward patches of food. But surface feeding is not as well understood, in part because it is harder to analyze tag data and quantify the size of prey patches at the water's surface, Barlow said.During a field research trip to study blue whales off the coast of New Zealand in 2017, Torres and her team observed surface feeding from their boat on multiple occasions. They also noted that the density of krill patches was greater closer to the water's surface.The researchers collected data that showed blue whales had relatively short dive times overall, about 2.5 minutes, compared to other blue whale populations, such as those off the coast of California, which average dives of about 10 minutes. When surface foraging was observed, the dive time of New Zealand blue whales dropped even more, to 1.75 minutes.Using a drone, the researchers captured video of a blue whale surface feeding on a patch of krill. The footage illustrates a blue whale's feeding process, including decision-making about whether or not to eat patches of krill near the ocean's surface. The video, which was first shared publicly shortly after the research trip, went viral online. It also gave researchers another source of data to describe surface feeding behavior."The drone footage fills a gap in our understanding of surface feeding," Barlow said.Through the footage, the researchers were able to see how the whale used its right eye to target the prey. They were able to quantify the recognition distance from the whale to the prey and could measure how widely the whale opened its mouth to feed. The footage also showed the whale's decision to rotate from one side to the other to better capture the krill."The video allows us to describe a lot of really cool kinematics and body movement coordination by the whale that we haven't been able to see before," Torres said."The footage also allowed us to see the prey response in new way. We can see when the krill begin to flee as the whale approaches, which is really amazing. At the whale's fastest speed and acceleration, the krill begin to jump away just eight tenths of a second before the whale strikes at the krill patch."Though the researchers had surface feeding footage from just one whale, the footage included four encounters between that whale and surface prey patches, providing insight into decision-making processes by the whale in response to the size and orientation of the prey patches, Torres said."This footage highlights the value of using drones for study and observation of whales," she said. "Drone footage could be a good complement to data collected from tags for studying surface behaviors of whales."
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Animals
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April 21, 2020
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https://www.sciencedaily.com/releases/2020/04/200421112542.htm
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Human pregnancy is weird -- new research adds to the mystery
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From an evolutionary perspective, human pregnancy is quite strange, says University at Buffalo biologist Vincent Lynch.
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"For example, we don't know why human women go into labor," Lynch says. "Human pregnancy tends to last longer than pregnancy in other mammals if you adjust for factors like body size. The actual process of labor tends to last longer than in other animals. And human pregnancy and labor are also much more dangerous."With these oddities in mind, Lynch and colleague Mirna Marinic set out to investigate the evolution of a gene that helps women stay pregnant: the progesterone receptor gene.But the results of the study only add to the mystery, says Lynch, PhD, an assistant professor of biological sciences in the UB College of Arts and Sciences.Past research has shown that the progesterone receptor gene underwent rapid evolution in humans, and some scientists have suggested that these swift changes occurred because they improved the function of the gene. This is called positive selection.But Lynch and Marinic's study -- published online on April 17 in the journal Their research finds that while the progesterone receptor gene evolved rapidly in humans, there's no evidence to support the idea that this happened because those changes were advantageous. In fact, the evolutionary force of selection was so weak that the gene accumulated many harmful mutations as it evolved in humans, Lynch says.The results come from an analysis of the DNA of 115 mammalian species. These included a variety of primates, ranging from modern humans and extinct Neanderthals to monkeys, lemurs and lorises, along with non-primate mammalian species such as elephants, pandas, leopards, hippos, aardvarks, manatees and walruses.The findings were a surprise, Lynch says."We expected something very different. It opens up this mystery that we didn't anticipate," he says. "I thought that the progesterone receptor gene would have evolved to respond better to progesterone, to be better at suppressing inflammation or contractions to keep us pregnant for longer. It looks like it's the reverse: In human pregnancy, there's just an incredible amount of progesterone around, and yet the gene is less good at doing its job. I wonder if this might predispose us to things like preterm birth, which is not that common in other animals.""Pregnancy is such an everyday event -- none of us would be here without it -- and yet, so many aspects of this process remain puzzling," says Marinic, PhD, a postdoctoral researcher in the University of Chicago Department of Organismal Biology and Anatomy. "This study focused on an essential ingredient, progesterone signaling via progesterone receptors, and our results add another step toward deeper understanding of specificities of human pregnancy."The progesterone receptor gene is crucial to pregnancy because it provides cells with instructions for how to create tiny structures called progesterone receptors.During human pregnancy, these receptors detect the presence of progesterone, an anti-inflammatory hormone that pregnant women and the placenta produce at various points in time. When progesterone is present, the receptors jump into action, triggering processes that help keep women pregnant in part by preventing the uterus from contracting, reducing uterine inflammation, and suppressing the maternal immune response to the fetus, Lynch says.In addition to exploring the evolutionary history of the progesterone receptor gene, Lynch and Marinic conducted experiments to test whether mutations in the human version of the gene altered its function. The answer is yes.As the scientists wrote in their paper, "We resurrected ancestral forms of the progesterone receptor and tested their ability to regulate a target gene. We found that the human progesterone receptor forms have changed in function, suggesting the actions regulated by progesterone may also be different in humans. Our results suggest caution in attempting to apply findings from animal models to progesterone biology of humans."The research was funded by the March of Dimes and the Burroughs Wellcome Fund Preterm Birth Initiative.
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Animals
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April 21, 2020
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https://www.sciencedaily.com/releases/2020/04/200421090558.htm
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Lizards develop new 'love language'
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Relocated in small groups to experimental islands, lizards rapidly and repeatedly developed new chemical signals for communicating with each other. Free from the risk of predators and intent to attract potential mates, male lizards produce a novel chemical calling card, according to new research from Washington University in St. Louis.
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Studies of animal signal evolution usually focus on acoustic and visual signals -- like the complex warbling in a bird's song or the bright flashes of color on fish scales. Chemical signals between animals are less obvious to humans and more technically complex to parse. Much of the existing research on these signals has focused on insect pheromones relevant to certain agricultural applications.But chemical signals are the oldest and most widespread communication mode, spanning bacteria to beavers. As such, they represent a valuable opportunity for decoding how animals communicate and perceive the world around them, researchers said."What we've discovered is that within species there is important variation in chemical signals depending on your context: Who's trying to eat you, who wants to mate with you and who you're trying to compete with," said Colin Donihue, a postdoctoral fellow in biology in Arts & Sciences at Washington University in St. Louis and lead author of a new study published April 21 in the Both lizards and snakes collect chemical cues from their surroundings by flicking out their slender forked tongues, then process those cues using a well-developed sensory organ in the roof of their mouths.Lizards deposit their chemical messages encoded in secretions from specialized glands located on their inner thighs. The secretions are a waxy cocktail of lipid compounds that contains detailed information about the individual lizard that produced them.In this study, researchers relocated groups of eight male and 12 female Aegean wall lizards (Podarcis erhardii) from a single source population in Naxos, Greece, to five small islets that lacked predators. Under normal conditions, these lizards would have to contend with a number of native and non-native predators -- including snakes, birds and cats.Free from predators on the small islets, the lizard populations grew rapidly and competition for resources was fierce.Each of the relocated lizards was individually tagged so they could be identified when the researchers returned to check up on them. Over the next four years, the scientists revisited the populations, tracking the fates of the relocated lizards and their offspring.What they found was striking: On each of the predator-free islands, lizards rapidly and repeatedly developed a new chemical "mix" that was distinct from that of lizards in the source population. The changes were apparent after only four generations.For the first time, researchers believe that they have demonstrated solid evidence that lizards can "put on a new cologne" to suit their setting."Signals to attract mates are often conspicuous to predators," said Simon Baeckens, a postdoctoral fellow at the University of Antwerp in Belgium and co-author of the new paper. "As such, sexual signals present a compromise between attractiveness and avoidance of detection. However, on these islets, there is no constraint on the evolution of highly conspicuous and attractive signals."In the experimental islands, we found that the 'signal richness' of the lizard secretions is the highest -- meaning that the number of different compounds that we could detect in the secretion is the highest," Baeckens added. "Our previous research suggests that this more elaborate signal might advertise the high quality of a male."Donihue continued: "Animals have spent over a billion years developing a complex chemical communication library. But we only invented the technology to identify many of those chemicals a century ago, and the experiments for understanding what those chemicals mean for the animals in nature have only just begun."We found that animal chemical cues can rapidly and flexibly change to suit new settings, but this is only the beginning for understanding what the lizards are saying to each other."
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Animals
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April 20, 2020
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https://www.sciencedaily.com/releases/2020/04/200420125456.htm
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Promiscuity in the Paleozoic: Researchers uncover clues about vertebrate evolution
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To look at how life evolved, scientists usually turn to the fossil record, but this record is often incomplete. Researchers from the Okinawa Institute of Science and Technology Graduate University (OIST), alongside an international team of collaborators, have used another tool -- the chromosomes of living animals -- to uncover clues about our past. The study, published in
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"It's remarkable that although these events occurred almost half a billion years ago, we can figure them out by looking at DNA today," said Professor Daniel Rokhsar, who leads OIST's Molecular Genetics Unit.Chromosomes are tiny structures that carry an organism's genetic material. They normally come in paired sets, with one set inherited from each parent. While humans have 23 pairs, this number varies across species.The study found that, even over hundreds of millions of years, chromosomes can be surprisingly stable. Although mutations and rearrangements have occurred, the chromosomes of modern animals have striking similarities to each other."We can use these similarities to trace our evolution and infer biology from the distant past," said Professor Rokhsar, "If a group of genes is carried together on the same chromosomes in two very different animals -- say, snails and sea stars -- then these genes were also likely together on the same chromosome in their last common ancestor."Two former OIST postdoctoral scholars, Professor Oleg Simakov, now at the University of Vienna, and Dr. Ferdinand Marlétaz, now at University College, London, led the study that compared the chromosomes of amphioxus, a small marine invertebrate, to those of other animals, including mollusks, mammals, birds, frogs, fish, and lampreys.After accounting for a handful of rearrangements, they concluded that the chromosomes of amphioxus resemble those of long-extinct early vertebrate ancestors and confirmed the existence of 17 ancient chromosomal units. The researchers then traced the evolution of these ancient chromosomes in living vertebrates."Reconstructing the ancestral chromosomes was the key that allowed us to unlock several puzzles of early vertebrate evolution," said Professor Rokhsar.The puzzles center on a phenomenon known as 'genome duplication.' In the 1970s, geneticist Susumu Ohno suggested that vertebrate genomes were doubled, perhaps repeatedly, relative to their invertebrate ancestors. Genomic studies have confirmed and refined this suggestion, but how many doublings there were, and how and when they occurred, are still debated.Part of the challenge is that duplicated genomes change rapidly, and these changes can obscure the duplication itself. Although a doubled genome starts with redundant copies of every gene, most of these extra copies will be inactivated by mutation and eventually lost; the doubled chromosomes themselves may also become scrambled.Using the 17 ancestral chromosome pairs as an ancient anchor, the researchers concluded that there were two separate instances of genome doubling.The first duplication is shared by all living vertebrates -- both the jawed vertebrates, including humans, birds, fish, and frogs, as well as the jawless lampreys and their relatives. The researchers inferred that this most ancient duplication occurred about five hundred million years ago, around the same time the earliest vertebrate fossils appear.The second duplication is shared only by jawed vertebrates. The researchers found that, unlike the first event, gene loss after the second doubling occurred unevenly across the two sets of chromosomal copies -- a surprising but informative feature."This kind of uneven gene loss is the hallmark of a genome duplication that follows the hybridization of two species," said Professor Rokhsar.Usually, the hybrid offspring of two different species are infertile, in part because the chromosomes from the two parents aren't properly coordinated. But very occasionally, in some fish, frogs, and plants, the hybrid genome becomes doubled to restore chromosomal pairing. The resulting offspring have twice as many chromosomes as their mismatched parents -- and are often more vigorous. The new study unexpectedly found that such hybrid-doubling occurred in our ancient ancestors."Over 450 million years ago, two different species of fish mated and, in the process, spawned a new hybrid species with twice as many chromosomes," said Professor Rokhsar, "And this new species would become the ancestor of all living jawed animals -- including us!"
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Animals
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April 17, 2020
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https://www.sciencedaily.com/releases/2020/04/200417212930.htm
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Extinction of threatened marine megafauna would lead to huge loss in functional diversity
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In a paper published in
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Defined as the largest animals in the oceans, with a body mass that exceeds 45kg, examples include sharks, whales, seals and sea turtles.These species serve key roles in ecosystems, including the consumption of large amounts of biomass, transporting nutrients across habitats, connecting ocean ecosystems, and physically modifying habitats.Traits, such as how large they are, what they eat, and how far they move, determine species' ecological functions. As a result, measuring the diversity of traits allows scientists to quantify the contributions of marine megafauna to ecosystems and assess the potential consequences of their extinction.The team of researchers -- led by Swansea University's Dr Catalina Pimiento -- first compiled a species-level trait dataset for all known marina megafauna to understand the extent of ecological functions they perform in marine systems.Then, after simulating future extinction scenarios and quantifying the potential impact of species loss on functional diversity, they introduced a new index (FUSE) to inform conservation priorities.The results showed a diverse range of functional traits held by marine megafauna, as well as how the current extinction crisis might affect their functional diversity.If current trajectories are maintained, in the next 100 years we could lose, on average, 18% of marine megafauna species, which will translate in the loss of 11% of the extent of ecological functions. Nevertheless, if all currently threatened species were to go extinct, we could lose 40% of species and 48% of the extent of ecological functions.Sharks are predicted to be the most affected, with losses of functional richness far beyond those expected under random extinctions.Dr Catalina Pimiento, who led the research from Swansea University said:"Our previous work showed that marine megafauna had suffered an unusually intense period of extinction as sea levels oscillated several million years ago. Our new work shows that, today, their unique and varied ecological roles are facing an even larger threat from human pressures."Given the global extinction crisis, a crucial question is to what extent nature holds a back-up system. In the event of extinction, will there be remaining species that can perform a similar ecological role?Dr John Griffin, a co-author on the study from Swansea University adds:"Our results show that, among the largest animals in the oceans, this so-called "redundancy" is very limited -- even when you roll in groups from mammals to molluscs. If we lose species, we lose unique ecological functions. This is a warning that we need to act now to reduce growing human pressures on marine megafauna, including climate change, while nurturing population recoveries."The newly introduced conservation metric, FUSE (Functionally Unique, Specialised and Endangered) identifies threatened species of particular importance for functional diversity. The highest-scoring FUSE species include the green sea turtle, the dugong and the sea otter. A renewed focus on these, and other highly-scoring FUSE species, will help ensure the maintenance of ecological functions provided by marine megafauna.In addition to Pimiento and Griffin, other authors include Fabien Leprieur (Université de Montpellier), Daniele Silvestro (University of Fribourg), Jonathan Lefcheck (Smithsonian Environmental Research Center), Camille Albouy (IFREMER, France), Doug Rasher (Bigelow Laboratory for Ocean Sciences), Matt Davis (Natural History Museum of Los Angeles County) and Jens-Christian Svenning (Aarhus University).
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Animals
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April 17, 2020
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https://www.sciencedaily.com/releases/2020/04/200415110439.htm
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Bees point to new evolutionary answers
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Evolutionary biology aims to explain how new species arise and evolve to occupy myriad niches -- but it is not a singular or simplistic story. Rare bees found in high mountain areas of Fiji provide evidence that they have evolved into many species, despite the fact they can't readily adapt to different habitats.
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These bees -- discovered by a team of researchers from Flinders University, South Australian Museum, UniSA and University of Adelaide -- serve as a major warning about the impact of ongoing human-induced climate change and loss of biodiversity for different species.The Fijian bees are locked into very specific habitats, and when these have contracted and split due to past climate change, the bee populations also became fragmented, with some isolated populations eventually turning into new species."The adaptation to new habitats and niches is often assumed to drive the diversification of species, but we found that Fijian bee diversity arose from an inability to adapt," says Flinders University's James Dorey, lead author on a new paper that explains this research.The paper -- "Radiation of tropical island bees and the role of phylogenetic niche conservatism as an important driver of biodiversity," by James Dorey, Scott Groom, Elisha Freedman, Cale Matthews, Olivia Davies, Ella Deans, Celina Rebola, Mark Stevens, Michael Lee and Michael Schwarz -- has been published by "Our genetic data show how a single bee-colonisation in Fiji gave rise to over 20 endemic bee species largely constrained to cooler, high elevations," says Dorey. "At least for Fijian bees, a relative inability to adapt has created a species-making machine."New Fijian bee species evolved when a single ancestral species colonised and spread over lowland areas during cool periods, but were later restricted to different mountaintops as the climate warms and the lowlands become too hot for comfort. The isolated populations later become new species. Each subsequent climate cycle has the potential to generate new species."Perhaps, if Darwin had studied Fijian bees instead of Galapagos finches, he might have come to rather different conclusions about the origin of species," adds Flinders Univeristy's Associate Professor Mike Schwarz, who was part of the research group.One of the major arguments at the core of evolutionary theory suggests that species arise from adaptive radiation into new niche spaces, with gene flow between the new and ancestral populations subsequently inhibited, eventually leading to speciation. As an alternative, phylogenetic niche conservatism points to the inability of a lineage to adapt to new or changing environments, in turn, promoting speciation when populations become isolated as their preferred habitats contract.This is what the researchers found in the high mountain areas of Fiji. Of the 22 Fijian bee species they identified, most have very narrow elevational ranges (constrained by temperature) -- and 14 species were only recovered from single mountain peaks."This demonstrates how slowly bees have adapted to new climates, since the colonisation of Fiji," says Dorey. 'We further highlight that such phylogenetic signals could indicate climate-related extinction risks. Indeed, one Fijian bee species (Homalictus achrostus) appears to be at serious risk of extinction, with sightings becoming much rarer since its initial discovery in the 1970s. This raises concerns for the 13 other species that we have, so far, only found on single mountain tops. They have nowhere to go if climate continues to warm and represent 14 very good reasons to curb global greenhouse gas emissions."
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Animals
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April 16, 2020
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https://www.sciencedaily.com/releases/2020/04/200416151800.htm
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Genetic variation not an obstacle to gene drive strategy to control mosquitoes
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New research from entomologists at UC Davis clears a potential obstacle to using CRISPR-Cas9 "gene drive" technology to control mosquito-borne diseases such as malaria, dengue fever, yellow fever and Zika.
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The idea is to create genetically engineered mosquitoes (GEM) that either fail to reproduce, reducing the mosquito population, or that resist carrying viruses and parasites that cause disease. These mosquitoes would be created in a lab and released to interbreed with wild mosquitoes.That's where gene drive technology comes in. Using the Cas 9 enzyme, researchers can ensure that the new, modified genes would be inherited by all of the mosquito's offspring when they mate with wild mosquitoes.Cas-9 works by recognizing a 23-base pair stretch of DNA. A number of research teams have pointed out that mosquito genomes carry so much DNA sequence variation that a significant proportion of any wild mosquito population will almost certainly be resistant to gene drive. If resistance to the gene drive is favorable to the mosquito, then the gene drive strategy will fail, they argue.A new study by Hanno Schmidt, Gregory Lanzaro and colleagues at the Vector Genetics Laboratory in the UC Davis School of Veterinary Medicine, published in "Our results demonstrate that the high level of genetic diversity carried by mosquito populations in nature should not influence the sustainability of strategies based on the introduction of pathogen blocking genes. This is great news for those pursuing a GEM strategy for the elimination of malaria," Lanzaro said.Additional authors on the paper are Travis Collier, Mark Hanemaaijer, Parker Houston and Yoosook Lee, all at the Vector Genetics Laboratory. Funding was provided by the UC Irvine Malaria Initiative, the CDC and NIH.As part of the multi-campus UC Irvine Malaria Initiative the UC Davis team is tasked with developing a strategy to move GEM from the laboratory to contained field trials at sites in Africa. A major part of this work is a description of the genetics of mosquito populations at putative sites.
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Animals
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April 16, 2020
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https://www.sciencedaily.com/releases/2020/04/200416091953.htm
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Bornean treeshrews can take the heat
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As human activity shapes Earth's climate, animals must increasingly adapt to new environmental conditions. The thermoneutral zone -- the ambient temperature range in which mammals can maintain their body temperature without expending extra energy -- is a key factor in estimating a species' ability to survive in a warming world.
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Reptiles and other ectotherms that rely on the environment to regulate their body temperature are believed to be more vulnerable to global warming in the tropics than in temperate climates. However, less is known about small tropical mammals, especially those active during the day.To better understand if small tropical mammals also have increased vulnerability as their environments heat up, Danielle Levesque, University of Maine assistant professor of mammology and mammal health, and collaborators from the Universiti Malaysia Sarawak studied Bornean treeshrews. They measured the oxygen consumption of the wild-caught lesser treeshrews (Tupaia minor) over a range of temperatures, calculating the animals' resting metabolic rate and thermoneutral zone.The team found that, like other treeshrew species, the animals exhibited more flexibility in body temperature regulation than other small mammals. This contradicts current assumptions that the upper limit of the thermoneutral zone between mammal species has little variation. The findings highlight the importance of further research on the energetics of mammals in the equatorial tropics.
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Animals
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April 15, 2020
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https://www.sciencedaily.com/releases/2020/04/200415171435.htm
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Low-cost imaging system poised to provide automatic mosquito tracking
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Mosquito-transmitted diseases such as malaria, dengue and yellow fever are responsible for hundreds of thousands of deaths every year, according to the World Health Organization (WHO). A new low-cost imaging system could make it easier to track mosquito species that carry disease, enabling a more timely and targeted response.
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"A remote system like ours can dramatically reduce the labor needed to monitor mosquitos in a given area, thus greatly increasing the capability to do more monitoring," said research team leader Adam Goodwin from Johns Hopkins University, USA. "If you can provide more mosquito data, then you will more quickly catch outbreaks and save more lives."In The Optical Society (OSA) journal "The new system is a classic application of an internet of things (IoT) device," said Goodwin. "It could eventually be paired with computer vision algorithms to automatically determine species and provide that information to public health systems."In the many areas of the world where mosquito-transmitted disease is problematic, understanding which mosquito species are present in what numbers requires continually trapping mosquitoes at multiple locations. A worker must then drive around a county or region to drop off and pick up hundreds of traps per week and bring the specimens back to the lab to be identified under a microscope."Our new optical system can be placed inside a traditional mosquito trap to provide remote surveillance of the abundance, diversity and distribution of mosquito species," said Goodwin. "Using imaging is particularly appealing because as long as image quality is high, several mosquitos could be identified from an image at once."When designing the system, the researchers focused on the ability to accurately identify Aedes aegypti mosquitos, which can spread Zika, dengue, chikungunya and yellow fever. This invasive species is native to Africa but has established itself in many parts of the world, including North America, Europe and Asia. They say that same approach could be applied to other insects as long as there is a way to capture and reliably image it.Using optics and camera sensors that are readily commercially available, the researchers optimized their optical setup to achieve a resolution that balanced the need to image many mosquitos at once with the ability to see enough details to identify the mosquito species."Our new system would be particularly useful in monitoring Aedes aegypti in hard to reach areas and at commercial ports of entry where invasive species can be brought from other countries," said Goodwin. "It could also expand current surveillance operations for regions already monitoring local populations of Aedes aegypti."In most cases, public health systems only need to determine if there are changes in the number or type of mosquitos from day to day or hour to hour, not minute to minute. This means a camera sensor would only need to be turned on a few times a day at most. This would keep the power consumption within the range feasible for an internet-connected device.To test the new system, the researchers compared entomologists' ability to classify specimens from a digital microscopy image and images from the remote imaging system. There was not a significant difference in their capabilities between the image types. Although the entomologists didn't perform well on species classification for either the microscopy images or the remote system images, they did very well on genus classification."Entomologists are not used to identifying specimens from an image because they normally have the specimen in person and manipulate it with tweezers under a microscope," said Goodwin. "However, recent work using convolutional neural networks to classify mosquitos from an image does show promise."The researchers plan to continue optimizing the remote trap and plan to integrate computer vision algorithms as well as internet-connectivity into the system. "This would enable species information to be sent directly to the public health system for decision-making," said Goodwin. "This is where we think the system will really shine."
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April 15, 2020
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https://www.sciencedaily.com/releases/2020/04/200415152923.htm
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Questionnaire survey identifies potential separation-related problems in cats
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The first questionnaire survey to identify possible separation-related problems in cats found 13.5 percent of all sampled cats displayed potential issues during their owner's absence, according to a study published April 15, 2020 in the open-access journal
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Though many studies have been conducted on owner separation problems in dogs, little work has been done to assess potential separation-related problems in cats. Despite the common belief that cats are happy being left alone for long periods of time, recent studies in cats and their owners suggest that pet cats are social and develop bonds with their owners.In order to assess separation-related problems in cats, de Souza Machado and colleagues developed a questionnaire for use with cat owners. Based on surveys in similar studies with dogs, the questionnaire asked owners to provide basic information on each cat; describe whether their cat displayed certain behaviors when the owner was absent; and describe themselves and their cat interactions, as well as the cat's living environment. The questionnaire was given to 130 owners of adult cats living in the city of Juiz de Fora in Minas Gerais, Brazil, for a total of 223 completed questionnaires (one per cat).After assessing and categorizing responses for each category, the authors statistically analyzed their results. The data showed 13.5 percent of the sampled cats (30 out of 223) met at least one of the criteria for separation-related problems, with destructive behaviour most frequently-reported (present in 20 of the 30 cats). The other behaviors or mental states identified were: excessive vocalization (19 out of 30 cats), inappropriate urination (18 cats), depression-apathy (16 cats), aggressiveness (11 cats), agitation-anxiety (11 cats) and inappropriate defecation (7 cats). The data also showed these cats were associated with households with no female residents, households with owners aged 18 to 35 years, and/or households with at least two female residents, as well as with not having access to toys (P=0.04) and/or having no other animal in the house (P=0.04).This questionnaire still requires further validation based on direct observation of cat behavior. It's also limited by a reliance on owners being able to accurately interpret and report their cats' actions in their absence (for instance, scratching on surfaces is normal in cats, though some owners may consider it destructive).Although there's more work to be done elucidating the relationship between humans and pet cats, this questionnaire can act as a starting point for future research, in addition to indicating certain environmental factors (like toys) that could help cats with separation issues.The authors add: "This study provides information about behavioral signs consistent with separation-related problems (SRP) in a sampled population of domestic cats, as well as about the management practices used by their owners. The questionnaire identified that about 13% of cats may have signs consistent with SRP according to their owners' reports, and therefore, it could be a promising tool for future research investigating SRP in cats."
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April 15, 2020
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https://www.sciencedaily.com/releases/2020/04/200415133640.htm
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Pterosaurs and other fossil flyers to better engineer human-made flight
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Pterosaurs were the largest animals ever to fly. They soared the skies for 160 million years -- much longer than any species of modern bird. Despite their aeronautic excellence, these ancient flyers have largely been overlooked in the pursuit of bioinspired flight technologies. In a review published April 15 in the journal
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"There's a lot of really cool stuff in the fossil record that goes unexplored because engineers generally don't look to paleontology when thinking about inspiration for flight," says first author Liz Martin-Silverstone (@gimpasaura), a post-doctoral researcher and paleontologist at the University of Bristol. "If we're only looking at modern animals for inspiration, we're really missing a large degree of the morphology out there and ignoring a lot of options that I think could be useful."Previously, engineers have largely focused on the physiology of modern birds and insects when designing aeronautic technology like drones and planes; they might not think to examine fossils that -- by their nature -- are often incomplete. However, Martin-Silverstone says there are a select few pterosaur fossils that provide extraordinarily deep insight into the anatomy of their wings, which is essential for understanding their flight capabilities."There are two or three absolutely amazingly preserved pterosaur fossils that let you see the different layers within the wing membrane, giving us insight into its fibrous components. Also, some fossils are preserved enough to show the wing attachments beneath the hip," she says. "While you don't know exactly the shape of the wing, by knowing the membrane attachments you can model the effectiveness of different wing shapes and determine which would have performed best in natural conditions." Analyzing the morphology and predicted flight mechanics of these ancient creatures has revealed novel tactics that don't exist in modern flyers.Becoming airborne is one example. Launching into the air through a leap or jump, also known as ballistic launch, is standard throughout the animal kingdom. However, larger birds require a running start to gain enough momentum for lift-off. Pterosaurs, on the other hand, may have developed a method to launch from a stationary position despite some specimens weighing nearly 300 kilograms. One hypothesis, proposed by review co-author Mike Habib (@aeroevo) of the Dinosaur Institute at the Natural History Museum of Los Angeles County, suggests that the wing membrane and the robust muscle attachments in the wings allowed pterosaurs to generate a high-powered leap off of their elbows and wrists, giving them enough height to become airborne."Today, something like a drone requires a flat surface to launch and is quite restricted on how it actually gets into the air. The unique launch physiology of pterosaurs might be able to help solve some of these problems," Martin-Silverstone says.Pterosaurs can also provide insights on how to prevent flight instability once in the air. Contrary to how sails can become unstable in a strong wind, pterosaurs evolved strategies to resist flutter of their broad wings. "So far we've struggled to design things like flight suits that can resist the pressures of flight. If we can understand how pterosaurs did it, for instance by understanding how their wing membrane was actually structured, then that's something we can use to answer modern engineering questions," she says.These unique physiological elements aren't limited to pterosaurs, either. Other ancient flyers, like Microraptor, had feathered wings on both their arms and legs, while newly discovered dinosaur, Yi qi, had wings that combine feathers with a bat-like membrane -- a body plan that has never been repeated since their extinction. As such, the authors say many flight strategies remain to be properly explored.Martin-Silverstone suggests that if we combine our knowledge from flyers both living and extinct, we will have a much better chance of overcoming the hurdles still hindering human-made flight. She says: "We want biologists and engineers alike to reach out to paleontologists when they are looking to solving flight problems, as there might be something extinct that could help. If we limit ourselves to looking at the modern animals, then we're missing out on a lot of diversity that might be useful."
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April 15, 2020
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https://www.sciencedaily.com/releases/2020/04/200415133421.htm
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Logging threatening endangered caribou
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Cutting down forests means we're also cutting down woodland caribou, says a pioneering study by University of Guelph ecologists showing that logging in Ontario's extensive boreal stands threatens populations of the elusive but iconic herbivore.
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In what integrative biology professor John Fryxell calls the first comprehensive study looking at the status of endangered woodland caribou across Ontario, the team found habitat and food web changes caused by forestry are encouraging more wolf packs to prey on caribou. Labelling the study a "clarion call" for conservation measures, he said the new paper shows how human activity, particularly logging, is upsetting food webs and habitat involving caribou, wolves and moose."It's death by a million cuts," said Fryxell. "Woodland caribou are an iconic species in Indigenous culture, integral to our historical development and a cornerstone in the functioning of boreal food webs. I think of the caribou as a canary in the coal mine for the long-term sustainability and quality of the boreal forest to protect other wildlife."Published recently in the Journal of Ontario's woodland caribou number several thousand animals. An officially endangered species, woodland caribou live below the tree line across most of Canada except the Atlantic provinces.Logging has moved northward in Ontario over recent decades. As cut forests regrow, their mix of new trees and shrubs attracts moose. Higher moose populations in turn attract wolves, placing caribou at risk of being hunted as well.Those caribou could move farther north, said Fryxell, but perhaps not soon enough to sustain their numbers.Over six years, the team studied two sites in northern Ontario spanning about 23,000 square kilometres in all.One site in Nakina, located about 160 kilometres north of Lake Superior, has been logged extensively since 1970. Regenerating forests contain more deciduous trees such as poplar and willow as well as thicker undergrowth.The Pickle Lake site, dominated by stands of jack pine, is located about a seven-hour drive from Thunder Bay, beyond the northern limit for forestry. That made for a perfect natural experiment for the researchers to compare conditions in both locations.To see what caribou might be eating, they sampled kinds of plants growing in each site and analyzed the footage collected from the video collars, or "critter cams." Caribou eat mostly lichen on the ground and growing on trees.The researchers also analyzed the information collected from the GPS-tracking radio collars on wolves. Multiple pings from a single spot over an extended period "usually means they're eating something," said Fryxell.Team members then visited those sites to verify what prey had been eaten.The researchers entered their information into computer models that estimate whether a caribou population will produce enough young to sustain itself or not. They found that caribou in the disturbed site were not self-sustaining, unlike healthier populations at Pickle LakeFryxell said the results likely would apply farther north in Ontario and in other parts of Canada where woodland caribou are endangered by resource extraction.He said forestry companies need to consider the long-term effects of their operations on plants and animals. Companies should practice rotation cutting to prevent clear-cutting and allow forests to regenerate, said Fryxell.More immediately, resource managers might need to consider culling wolves or hindering their movements by turning old logging roads back into forest.He said there's no evidence that either wolves or moose are threatened.With plans for further development of Northern Ontario communities, Fryxell hopes to see governments, conservationists, Indigenous groups, industry and others work together to address threats to woodland caribou. "We have an opportunity to learn from what was done in the past to manage better in the future."
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April 14, 2020
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https://www.sciencedaily.com/releases/2020/04/200414084301.htm
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A new species of black endemic iguanas in Caribbeans is proposed for urgent conservation
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A newly discovered endemic species of melanistic black iguana (
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So far, there have been three species of iguana known from The Lesser Antilles: the Lesser Antillean iguana (Iguana delicatissima), a species endemic to the northernmost islands of the Lesser Antilles; and two introduced ones: the common iguana (Iguana iguana iguana) from South America and the green iguana (The newly described species is characterised with private microsatellite alleles, unique mitochondrial ND4 haplotypes and a distinctive black spot between the eye and the ear cavity (tympanum). Juveniles and young adults have a dorsal carpet pattern, the colouration is darkening with aging (except for the anterior part of the snout).It has already occurred before in Guadeloupe that Common Green Iguana displaced the Lesser Antilles iguanas through competition and hybridization which is on the way also in the Lesser Antilles. Potentially invasive common iguanas from the Central and South American lineages are likely to invade other islands and need to be differentiated from the endemic melanistic iguanas of the area.The IUCN Red List lists the green iguana to be of "Least Concern," but failed to differentiate between populations, some of which are threatened by extinction. With the new taxonomic proposal, these endemic insular populations can be considered as a conservation unit with their own assessments."With the increase in trade and shipping in the Caribbean region and post-hurricane restoration activities, it is very likely that there will be new opportunities for invasive iguanas to colonize new islands inhabited by endemic lineages," shares the lead researcher prof. Frédéric Grandjean from the University of Poitiers (France).Scientists describe the common melanistic iguanas from the islands of Saba and Montserrat as a new taxon and aim to establish its relationships with other green iguanas. That can help conservationists to accurately differentiate this endemic lineage from invasive iguanas and investigate its ecology and biology population on these two very small islands that are subject to a range of environmental disturbances including hurricanes, earthquakes and volcanic eruptions."Priority actions for the conservation of the species The key stakeholders in conservation efforts for the area are the Dutch Caribbean Nature Alliance (DCNA), the Saba Conservation Foundation (SCF), the Montserrat National Trust (MNT) and the UK Overseas Territories Conservation Forum (UKOTCF), which, the research team hope, could take measures in order to protect the flagship insular iguana species, mainly against alien iguanas.
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April 13, 2020
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https://www.sciencedaily.com/releases/2020/04/200413150744.htm
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Molecular and isotopic evidence of milk, meat and plants in prehistoric food systems
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A team of scientists, led by the University of Bristol, with colleagues from the University of Florida, provide the first evidence for diet and subsistence practices of ancient East African pastoralists.
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The development of pastoralism is known to have transformed human diets and societies in grasslands worldwide. Cattle-herding has been (and still is) the dominant way of life across the vast East African grasslands for thousands of years.This is indicated by numerous large and highly fragmentary animal bone assemblages found at archaeological sites across the region, which demonstrate the importance of cattle, sheep and goat to these ancient people.Today, people in these areas, such as the Maasai and Samburu of Kenya, live off milk and milk products (and sometimes blood) from their animals, gaining 60 -- 90 percent of their calories from milk.Milk is crucial to these herders and milk shortages during droughts or dry seasons increase vulnerabilities to malnutrition, and result in increased consumption of meat and marrow nutrients.Yet we do not have any direct evidence for how long people in East Africa have been milking their cattle, how herders prepared their food or what else their diet may have consisted of.Significantly though, we do know they have developed the C-14010 lactase persistence allele, which must have resulted from consumption of whole milk or lactose-containing milk products. This suggests there must be a long history of reliance on milk products in the area.To address this question, the researchers examined ancient potsherds from four sites in Kenya and Tanzania, covering a 4000-year timeframe (c 5000 to 1200 BP), known as the Pastoral Neolithic, using a combined chemical and isotopic approach to identify and quantify the food residues found within the vessels. This involves extracting and identifying the fatty acids, residues of animal fats absorbed into the pot wall during cooking.The findings, published today in the journal This is entirely consistent with the animal bone assemblages from the sites sampled. Across this entire time frame, potsherds preserving milk residues were present at low frequencies, but this is very similar to modern pastoralist groups, such as the heavily milk-reliant Samburu, who cook meat and bones in ceramic pots but milk their cattle into gourds and wooden bowls, which rarely preserve at archaeological sites.In the broader sense, this work provides insights into the long-term development of pastoralist foodways in east Africa and the evolution of milk-centred husbandry systems. The time frame of the findings of at least minor levels of milk processing provides a relatively long period (around 4,000 years) in which selection for the C-14010 lactase persistence allele may have occurred within multiple groups in eastern Africa, which supports genetic estimates. Future work will expand to studies of other sites within the region.Dr Julie Dunne, from the University of Bristol's School of Chemistry, who led the study, said: "How exciting it is to be able to use chemical techniques to extract thousands of year-old foodstuffs from pots to find out what these early East African herders were cooking."This work shows the reliance of modern-day herders, managing vast herds of cattle, on meat and milk-based products, has a very long history in the region."
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April 13, 2020
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https://www.sciencedaily.com/releases/2020/04/200413132758.htm
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Scientists discover bent-toed gecko species in Cambodia
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A new species of bent-toed gecko (
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The species was discovered by Thy Neang during Wild Earth Allies field surveys in June-July 2019 on an isolated mountain named Phnom Chi in the Prey Lang Wildlife Sanctuary when he encountered an unusual species of bent-toed gecko. "It was an extremely unexpected discovery. No one thought there were undescribed species in Prey Lang," said Neang.The geckos were found to belong to the Bent-toed geckos of the genus The forest habitat in Phnom Chi remains in relatively good condition, but small-scale illegal gold extraction around its base threatens the newly discovered species. A second species of lizard, the scincid Sphenomorphus preylangensis, was also recently described from Phnom Chi by a team of researchers including Neang. These new discoveries underscore the importance of Prey Lang Wildlife Sanctuary for biodiversity conservation and the critical need to strengthen its management.Further, an assessment of "This exciting discovery adds another reptile species to science for Cambodia and the world. It also highlights the global importance of Cambodia's biodiversity and illustrates the need for future exploration and biological research in Prey Lang," said Neang."When [Neang] first returned from fieldwork and told me that he had found a species in the
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April 9, 2020
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https://www.sciencedaily.com/releases/2020/04/200409162311.htm
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Canada lynx disappearing from Washington state
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Canada lynx are losing ground in Washington state, even as federal officials are taking steps to remove the species' threatened status under the Endangered Species Act.
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A massive monitoring study led by Washington State University researchers has found lynx on only about 20% of its potential habitat in the state. The study, published recently in the The results paint an alarming picture not only for the persistence of lynx but many other cold-adapted species, said Dan Thornton, an assistant professor in WSU's School of the Environment."Lynx are good sentinel species for climate change," said Thornton, the corresponding author on the study. "They are specialized, have larger ranges and need really cold, snowy environments. So, as they go, they are like an early warning system for what's going to happen to other climate sensitive species."Wildfire, rising temperatures and decreasing snowpack have all hurt the lynx's ability to survive in Washington, the researchers found.In the last 24 years, large wildfires have ripped through northeastern parts of the state, destroying habitat for lynx and their favorite food: snowshoe hare. It can take as long as 20 to 40 years for that landscape to recover.The lack of snow and cold are also a problem, as lynx with their bigger paws are specially adapted to hunt on snow and for the prey that live there. As temperature rises, warmer adapted species like bobcat and cougar could also bring competition into lynx territory."We learned that lynx are responding strongly to many of these factors -- snow conditions, temperature and fire -- that are likely to change even more as the climate warms," said Thornton.The connection to Canadian populations is also key for the lynx survival in Washington, and that connection is complicated by differing conservation status. In Washington state, they are protected at the state and federal levels as a threatened species. In Canada, they are harvested for their pelts.The lynx's protected status in the U.S. may also change. Lynx are currently found in Maine, Minnesota, Montana, Colorado, Idaho and Washington, but a 2016 federal draft assessment found the species would disappear from its northern range without protection by 2100. However, a new assessment in 2018 concluded that the lynx could be removed from threatened status under the federal Endangered Species Act.Living in high, remote areas, lynx are challenging to study, and estimates of actual individuals are difficult to make, but according to an analysis by the Washington State Department of Fish and Wildlife based on data collected in the 1980s, the state used to have about 7,800 square miles of habitat capable of supporting 238 animals. In 2017, that estimate was revised down to about 2,300 square miles capable of supporting 38 to 61 lynx. This latest study adds strong evidence that their territory in Washington is further contracting.To document the elusive animals, WSU graduate student Travis King, the lead author on the study, covered thousands of kilometers and spent two summers in the field. He also relied upon many partners and volunteers, ranging from government natural resource agency employees and conservation groups to hikers and citizen scientists. The researchers and volunteers deployed and collected 650 camera traps which generated more than 2 million images which were, in turn, sorted with the help of dozens of WSU student volunteers.This is the first time such a comprehensive method using camera traps to track lynx has been employed. Thornton and his colleagues are now working to use the method to estimate the lynx range in Glacier National Park in Montana.This research was supported by a Seattle City Light Wildlife Research Grant, Conservation Northwest, the United States Forest Service and a Department of the Interior Northwest Climate Adaptation Science Center Research Fellowship. King received funding through the National Science Foundation Graduate Research Fellowship Program as well as Washington State University.
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Animals
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April 9, 2020
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https://www.sciencedaily.com/releases/2020/04/200409141528.htm
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Ancient teeth from Peru hint now-extinct monkeys crossed Atlantic from Africa
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Four fossilized monkey teeth discovered deep in the Peruvian Amazon provide new evidence that more than one group of ancient primates journeyed across the Atlantic Ocean from Africa, according to new USC research just published in the journal
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The teeth are from a newly discovered species belonging to an extinct family of African primates known as parapithecids. Fossils discovered at the same site in Peru had earlier offered the first proof that South American monkeys evolved from African primates.The monkeys are believed to have made the more than 900-mile trip on floating rafts of vegetation that broke off from coastlines, possibly during a storm."This is a completely unique discovery," said Erik Seiffert, the study's lead author and Professor of Clinical Integrative Anatomical Sciences at Keck School of Medicine of USC. "It shows that in addition to the New World monkeys and a group of rodents known as caviomorphs -- there is this third lineage of mammals that somehow made this very improbable transatlantic journey to get from Africa to South America."Researchers have named the extinct monkey Ucayalipithecus perdita would have been very small, similar in size to a modern-day marmoset.Researchers believe the site in Ucayali where the teeth were found is from a geological epoch known as the Oligocene, which extended from about 34 million to 23 million years ago.Based on the age of the site and the closeness of Ucayalipithecus to its fossil relatives from Egypt, researchers estimate the migration might have occurred around 34 million years ago."We're suggesting that this group might have made it over to South America right around what we call the Eocene-Oligocene Boundary, a time period between two geological epochs, when the Antarctic ice sheet started to build up and the sea level fell," said Seiffert. "That might have played a role in making it a bit easier for these primates to actually get across the Atlantic Ocean."Two of the Ucayalipithecus perdita teeth were identified by Argentinean co-authors of the study in 2015 showing that New World monkeys had African forebears. When Seiffert was asked to help describe these specimens in 2016, he noticed the similarity of the two broken upper molars to an extinct 32 million-year-old parapithecid monkey species from Egypt he had studied previously.An expedition to the Peruvian fossil site in 2016 led to the discovery of two more teeth belonging to this new species. The resemblance of these additional lower teeth to those of the Egyptian monkey teeth confirmed to Seiffert that Ucayalipithecus was descended from African ancestors."The thing that strikes me about this study more than any other I've been involved in is just how improbable all of it is," said Seiffert. "The fact that it's this remote site in the middle of nowhere, that the chances of finding these pieces is extremely small, to the fact that we're revealing this very improbable journey that was made by these early monkeys, it's all quite remarkable."In addition to Seiffert, the study's other authors are Marcelo Tejedor and Nelson Novo from the Instituto Patagónico de Geología y Paleontología (CCT CONICET -- CENPAT); John G. Fleagle from the Department of Anatomical Sciences, Renaissance School of Medicine, Stony Brook University; Fanny Cornejo and Dorien de Vries from the Interdepartmental Doctoral Program in Anthropological Sciences, Stony Brook University; Mariano Bond from CONICET, División Paleontología Vertebrados, Museo de Ciencias Naturales de La Plata and Kenneth E. Campbell Jr. from the Department of Vertebrate Zoology, Natural History Museum of Los Angeles County.The study was supported by J. Wigmore, W. Rhodes, and R. Seaver, who helped to fund the 1998 expedition that led to the recovery of the Ucayalipithecus partial upper molars; the Leakey Foundation, Gordon Getty, and A. Stenger who supported the fieldwork in 2016; and the Keck School of Medicine of USC and the U.S. National Science Foundation (BCS-1231288) which supported micro-CT scanning.
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April 9, 2020
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https://www.sciencedaily.com/releases/2020/04/200409141429.htm
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Scientists discover six new coronaviruses in bats
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Researchers with the Smithsonian's Global Health Program have discovered six new coronaviruses in bats in Myanmar -- the first time these viruses have been detected anywhere in the world. Future studies will evaluate the potential for transmission across species to better understand the risks to human health. According to the authors, the newly discovered coronaviruses are not closely related to coronaviruses Severe Acute Respiratory Syndrome (SARS CoV-1), Middle East Respiratory Syndrome (MERS) or COVID-19.
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The findings, published today in "Viral pandemics remind us how closely human health is connected to the health of wildlife and the environment," said Marc Valitutto, former wildlife veterinarian with the Smithsonian's Global Health Program and lead author of the study. "Worldwide, humans are interacting with wildlife with increasing frequency, so the more we understand about these viruses in animals -- what allows them to mutate and how they spread to other species -- the better we can reduce their pandemic potential."Researchers detected these new viruses while conducting biosurveillance of animals and people to better understand the circumstances for disease spillover as part of the PREDICT project. PREDICT, an initiative funded by the U.S. Agency for International Development (USAID), supports the global discovery and surveillance of pathogens that have the potential to spread from animals to humans. The PREDICT team in Myanmar consists of scientists from the Smithsonian; the University of California, Davis; Myanmar's Ministry of Agriculture, Livestock and Irrigation; Myanmar's Ministry of Health and Sports; and Myanmar's Ministry of Natural Resources and Environmental Conservation.The team focused their research on sites in Myanmar where humans are more likely to come into close contact with local wildlife due to changes in land use and development. From May 2016 to August 2018, they collected more than 750 saliva and fecal samples from bats in these areas. Experts estimate that thousands of coronaviruses -- many of which have yet to be discovered -- are present in bats.Researchers tested and compared the samples to known coronaviruses and identified six new coronaviruses for the first time. The team also detected a coronavirus that had been found elsewhere in Southeast Asia, but never before in Myanmar.Coronaviruses have caused widespread disease in humans, including SARS CoV-1, MERS and most recently the global COVID-19 pandemic. According to the authors, the newly discovered coronaviruses are not closely related to SARS CoV-1, MERS or COVID-19. Future studies are needed to evaluate their potential for spillover to other species to better understand the risks to human health.The authors say these findings underscore the importance of surveillance for zoonotic diseases as they occur in wildlife. The results will guide future surveillance of bat populations to better detect potential viral threats to public health."Many coronaviruses may not pose a risk to people, but when we identify these diseases early on in animals, at the source, we have a valuable opportunity to investigate the potential threat," said Suzan Murray, director of the Smithsonian's Global Health Program and co-author of the study. "Vigilant surveillance, research and education are the best tools we have to prevent pandemics before they occur."The Smithsonian's Global Health Program (GHP) leverages multidisciplinary expertise in wildlife medicine, conservation pathology, training of international professionals and investigation of emerging infectious disease to combat threats to conservation and public health worldwide. GHP is part of PREDICT teams in Myanmar and Kenya.GHP is a part of the Smithsonian Conservation Biology Institute (SCBI), which plays a leading role in the Smithsonian's global efforts to save wildlife species from extinction and train future generations of conservationists. SCBI spearheads research programs at its headquarters in Front Royal, Virginia, the Smithsonian's National Zoo in Washington, D.C., and at field research stations and training sites worldwide. SCBI scientists tackle some of today's most complex conservation challenges by applying and sharing what they learn about animal behavior and reproduction, ecology, genetics, migration and conservation sustainability.PREDICT is enabling global surveillance for viruses that may spillover from animal hosts to people by building capacities to detect and discover viruses of pandemic potential. The project is part of USAID's Emerging Pandemic Threats program and is led by the UC Davis One Health Institute. The core partners are USAID, EcoHealth Alliance, Metabiota, Wildlife Conservation Society and Smithsonian Conservation Biology Institute. Since 2009, scientists have worked in more than 30 countries in Latin America, Africa and Asia to strengthen capacity, put One Health in action and conduct surveillance for zoonotic diseases and emerging viral threats, including coronaviruses (e.g., SARS/MERS), filoviruses (e.g., Ebola), paramyxoviruses (e.g., Nipah/Hendra), influenza viruses (e.g., H1N1, H5N1, H7N9) and flaviviruses (e.g., Zika). As part of this effort, lab scientists around the world were also trained to perform viral testing -- a vital skill in case an outbreak should emerge. Data from the project (when approved by host-country governments) is shared with animal and human health sectors to inform decision making and is made available to the public and global health community at
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April 9, 2020
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https://www.sciencedaily.com/releases/2020/04/200409140013.htm
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How do mantis shrimp find their way home?
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Mantis shrimps have earned fame for their powerful punching limbs, incredibly unusual eyes, and vivid exoskeletons. And, it turns out, they're also really good at finding their way home. Through a series of painstaking experiments with these often-uncooperative creatures, Rickesh Patel has produced new findings on mantis shrimp navigation, published this week in
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Patel, a Ph.D. candidate in biological sciences at UMBC, found that the species of mantis shrimp he investigated relies on the sun, patterns in polarized light, and internal cues -- in that order -- to navigate directly back to their non-descript burrows. These straight-line returns often follow forays that meander and zig zag as the shrimp looks for a meal or a mate. The ability to get home quickly comes in handy when seeking shelter in the presence of predators, or a perceived one, as Patel noted on his first research fieldwork expedition.After his first year at UMBC, Patel traveled with Tom Cronin's lab to Lizard Island in the Great Barrier Reef to collect mantis shrimp for study. "As soon as they notice you, they'll turn around and zip straight to some sort of shelter," Patel says. Like a true scientist, "That got me wondering how they go about finding their way home."Scientists have written a great deal on navigation in other species -- primarily bees, ants, and mice -- but Patel's is the first work on navigation in mantis shrimp.First, Patel had to find a behavior he could work with to test ideas about how mantis shrimp navigate. So he created a small arena with an artificial shrimp burrow buried in sand. He placed the shrimp in the arena, and to his delight, the mantis shrimp was happy to occupy the small section of PVC pipe. Then he placed a piece of food at a distance from the burrow. He watched as the shrimp left its burrow, meandered until it found the food, and then returned to its burrow in a fairly straight line.From those initial observations, Patel hypothesized that mantis shrimps use a process called path integration to find their way home. In other words, they are somehow able to track both their distance and direction from their burrow."That was probably the most exciting part of the experiments for me, because I knew I had a really robust behavior that I could work with," Patel says. "Everything I did really extended from that initial point."After that first discovery, the challenging work began, to figure out what cues the animals were using to determine the path home.Patel built eight much larger arenas, each about 1.5 meters in diameter, to run his experiments. The first question he asked was whether the shrimp were using internal or external cues to go home.To test that, Patel created a setup that rotated the animal 180 degrees as it retrieved the food. If the shrimp was using external cues to remember its distance and direction from home, it would still head in the right direction. If it was using internal cues, based on the orientation of its own body, it would head in the opposite direction. In the first round of trials, the animals consistently headed in the exact opposite direction."That was really cool, but it didn't make a lot of sense," Patel says, "because an internal compass is going to be a lot less accurate than something that is tied to the environment." Then it hit him: "We just happened to have a really overcast week when I did these experiments, so I waited until we had a clear day, and then every time, they went right back home."Patel realized that his experiment perfectly demonstrated the hierarchy of cues used by the animals. They used external cues first, but when those weren't available, they used internal cues.That was the beginning of a long series of creative experiments that further teased out how these animals navigate. When Patel used a mirror to trick the animals into thinking the sun was coming from the opposite direction, they went the wrong way. This indicated they use the sun as a primary cue. When it was cloudy but not totally dark, they used polarization patterns in light, which are still detectable when it's overcast. And when the sky was completely covered, they reverted to their internal navigation system.For Patel, creating the experimental arenas -- essentially, the shrimp obstacle course -- was almost as fun as getting the results. "That's something I really enjoy -- building things, creating things," he shares. Patel studied art and biology as an undergraduate at California State University, Long Beach. "I think those skills lent me a hand in designing my experiments."Other skills Patel needed were patience and perseverance. "The animals will only behave maybe once a day, so if you scare the animal, you've lost that day," he says.For example, one of the experiments involved putting the animals on a track that pulled them to a new position, and seeing where they headed from there. "If the track is too jerky or goes too fast, they get scared and just don't behave," Patel says. "So I had to design the experiment so that it was so gentle they didn't realize they were being moved."All of Patel's patience has paid off with new findings that open up an array of future questions to answer. While path integration is well-documented in other species, mantis shrimp are the first to demonstrate the technique underwater. Looking up at the sky through water is a very different view than doing so through air, so Patel is curious how the animals' process is different from other species.Patel is also ultimately interested in the neural basis of navigation behavior, but "before you can investigate what's happening in the brain, you have to understand what the animal's doing," he says. "So that's why I really focused on the behavior work, to figure out what the animal is doing and what kind of stimuli are appropriate to show the animal that we can use to investigate its neurology."So far, other work has demonstrated that a brain region called the central complex has uncanny similarities between insects and mantis shrimps. This is especially interesting considering how far apart bees and shrimp are on the tree of life. The central complex is known to contribute to navigation in bees, so Patel is intrigued to learn more about its function in mantis shrimp. Alice Chou, another graduate student in the Cronin lab, is also investigating the brain structures of mantis shrimp.
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April 9, 2020
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https://www.sciencedaily.com/releases/2020/04/200409110524.htm
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Black rhinos eavesdrop on the alarm calls of hitchhiking oxpeckers to avoid humans
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In Swahili, red-billed oxpeckers are called Askari wa kifaru, or "the rhino's guard." Now, a paper appearing April 9 in the journal
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While conservation efforts have rebounded the critically endangered black rhino's numbers, poaching remains a major threat. "Although black rhinos have large, rapier-like horns and a thick hide, they are as blind as a bat. If the conditions are right, a hunter could walk within five meters of one, as long as they are downwind," says Roan Plotz (@RoanPlotz), a lecturer and behavioral ecologist at Victoria University, Australia., who co-authored the paper with ecological scientist Wayne Linklater (@PolitEcol) of California State University -- Sacramento. Oxpeckers, which are known to feed on the ticks and lesions found on the rhino's body, may make up for the rhino's poor eyesight by calling out if they detect an approaching human.To study the role that oxpeckers might play, Plotz and his team recorded the number of oxpeckers on two groups of the rhinos they encountered. Rhinos tagged with radio transmitters -- which allowed researchers to track them while evading detection from oxpeckers -- carried the bird on their backs more than half the time. The untagged black rhinos they found, on the other hand, carried no oxpeckers most of the time -- suggesting that other untagged rhinos that carried the birds might have avoided encountering the researchers altogether. "Using the differences we observed between oxpeckers on the tagged versus untagged rhinos, we estimated that between 40% and 50% of all possible black rhino encounters were thwarted by the presence of oxpeckers," says Plotz.Even when the researchers were able to locate the tagged rhinos, the oxpeckers' alarm calls still appeared to play a role in predator defense. The field team ran a "human approach" experiment, where one researcher would walk towards the rhino from crosswind while a colleague recorded the rhino's behavior. The field team recorded the number of oxpecker carried, the rhinos' behavior upon approach, and the distance of the researcher when either the rhinos became vigilant or, if undetected, it became unsafe to get any closer."Our experiment found that rhinos without oxpeckers detected a human approaching only 23% of the time. Due to the bird's alarm call, those with oxpeckers detected the approaching human in 100% of our trials and at an average distance of 61 meters -- nearly four times further than when rhinos were alone. In fact, the more oxpeckers the rhino carried, the greater the distance at which a human was detected," he says. He adds that these improved detection and distance estimates may even be conservative, because they don't take into account the untagged rhinos carrying oxpeckers that the team could not detect.When a rhino perceived the oxpecker alarm call, it nearly always re-oriented itself to face downwind -- their sensory blind spot. "Rhinos cannot smell predators from downwind, making it their most vulnerable position. This is particularly true from humans, who primarily hunt game from that direction," says Plotz.Taken together, these results suggest that oxpeckers are effective companions that enable black rhinos to evade encounters with people and facilitate effective anti-predator strategies once found. Some scientists even hypothesize that oxpeckers evolved this adaptive behaviour as a way to protect their source of food: the rhinos."Rhinos have been hunted by humans for tens of thousands of years, but the species was driven to the brink of extinction over the last 150 years. One hypothesis is that oxpeckers have evolved this cooperative relationship with rhinos relatively recently to protect their food source from human overkill," says Plotz.Despite this closely tied relationship, oxpecker populations have significantly declined, even becoming locally extinct in some areas. As a result, most wild black rhino populations now live without oxpeckers in their environment. But based on the findings in this study, reintroducing the bird back into rhino populations may bolster conservation efforts. "While we do not know that reintroducing the birds would significantly reduce hunting impacts, we do know oxpeckers would help rhinos evade detection, which on its own is a great benefit," says Plotz.Plotz says that these findings, inspired by a Swahili name, also highlight the importance of local knowledge. "We too often dismiss the importance of indigenous people and their observations. While western science has been incredibly useful, there are many insights we can learn from indigenous communities."
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April 9, 2020
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https://www.sciencedaily.com/releases/2020/04/200409100337.htm
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Sweet as: The science of how diet can change the way sugar tastes
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Researchers at the University of Sydney have discovered the basic science of how sweet taste perception is fine-tuned in response to different diets. While it has long been known that food can taste different based on previous experience, until now we didn't know the molecular pathways that controlled this effect.
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Professor Greg Neely at the Charles Perkins Centre and School of Life and Environmental Sciences with Professor Qiaoping Wang (formerly at the Charles Perkins Centre and now based at Sun Yat-Sen University, China) used fruit flies to study sweet taste. They learned that taste is highly subjective based on previous experience.Professor Neely said they learned four important things:2. This response uses the same machinery that the brain uses to learn.3. Pathways that can extend lifespan were also involved in enhancing taste perception, and diets in fruit flies that promote long life were also found to enhance taste perception.4. Lifespan, learning and sensory perception are linked in ways we are just starting to understand."We found that the fruit fly 'tongue' -- taste sensors on its proboscis and front feet -- can learn things using the same molecular pathways that the fly brain uses to learn things. Central to this is the neurotransmitter dopamine."It turns out these are also the same chemical pathways that humans use to learn and remember all sorts of things," Professor Neely said. "This really highlights how learning is a whole-body phenomenon; and was a complete surprise to us."Professor Wang, who led the study, said: "We were surprised to find that a protein-restricted diet that makes an animal live much longer also turns up the intensity of sucrose perception for that animal, and that is dependent on the same learning and longevity pathways."The response was also really specific. For example, when we fed flies food that had no sweetness, the animals' sweet taste perception was enhanced, but only for glucose, not for fructose. We have no idea why they specifically focus just on one kind of sugar when they perceive them both as sweet.""We also found that eating high amounts of sugar suppressed sweet taste perception, making sugar seem less sweet," Professor Neely said. "This finding, which occurs through a different mechanism, matched nicely with recent results from our colleague Monica Dus at the University of Michigan, who is the world expert in this area."The researchers found if they changed the diet of the fruit fly (increasing sugar, removing taste of sugar, increasing protein, changing sugar for complex carbohydrate), this drastically altered how well the fruit fly could taste subsequent sugar after a few days. Flies normally live about 80 days in optimal circumstances."We found that when flies ate unsweetened food, this made sugary food taste much more intense," Professor Wang said."Then we looked at all the proteins that changed in the fruit fly 'tongue' in response to diet, and we investigated what was happening," Professor Neely said.They found the sensation of taste is controlled by dopamine (the "reward" neuromodulator). The researchers then mapped the pathway and found the same pathways that are well established as controlling learning and memory or promoting long life also enhance taste sensation."While this work was conducted in fruit flies, the molecules involved are conserved through to humans. We know humans also experience changes in taste perception in response to diet, so it's possible the whole process is conserved; we will have to see," Professor Wang said.The research published in "Our first studies were focused on how different food additives impact the brain, and from this we found taste changed in response to diet, so here we followed up that observation and describe how that works," Professor Neely said. "Turns out the fly 'tongue' itself is remembering what has come before, which is kind of neat."
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April 8, 2020
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https://www.sciencedaily.com/releases/2020/04/200408220526.htm
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Hidden army: How starfish could build up numbers to attack coral reefs
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The coral-eating crown of thorns starfish that devastate tropical reefs can lie in wait as harmless young herbivores for more than six years while coral populations recover from previous attacks or coral bleaching, new research has shown.
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The diet of the juvenile starfish is algae. Juveniles remain on this vegetarian diet for at least four months and then, if there is an abundance of coral, the starfish typically switch to a coral diet.Research published today in "This Peter Pan effect means that populations of juvenile crown of thorns starfish can build up on reefs in the absence of coral," Ms Deaker said. "They could become a hidden army waiting to consume reefs as the reefs recover."As adults they grow to nearly a full metre in diameter and have a voracious appetite for coral, devastating critical reef habitats on the Great Barrier Reef and across the Indo-Pacific.Professor Byrne from the Sydney Environment Institute said: "Despite the notoriety of the large adult starfish and their propensity for coral prey, the juveniles eat algae. For outbreaks to arise, these algal-eating juveniles must transition into coral predators."How and when the juveniles switch to being coral predators remains something of a mystery to researchers but trying to understand the process is a crucial part in the fight to protect reef habitats from the starfish.In this study Ms Deaker and Professor Byrne, along with colleagues at the National Marine Science Centre, Coffs Harbour, showed that in response to coral scarcity, crown of thorns starfish can remain as herbivores for at least 6.5 years.The team reared two groups of starfish on algae for 10 months and 6.5 years. Both cohorts grew to the same maximum size -- 16 to 18 millimetres. Despite restricted growth on a vegetarian diet, there was no impact on the ability of the 6.5-year-olds to eat corals. After provision of coral prey, the one-year-old and 6.5-year-old juveniles had the same growth pattern."Suppression of the switch to a coral diet due to scarcity of prey might occur after coral bleaching events," Ms Deaker said. "The remarkable resilience of juvenile starfish to coral scarcity complicates our ability to age them and indicates the potential for reserves of juveniles to accumulate on the reef to seed outbreaks when favourable conditions arise."The research shows that starfish modelling needs to account for the possibility that an extended herbivorous phase of crown of thorns starfish has the potential to allow the formation of a reserve population in reef habitats.Professor Byrne said: "Another important implication of our findings is the possibility that the current adult starfish killing programs used to manage crown of thorns starfish might, in fact, trigger a feedback mechanism in the starfishes' transition to coral predator as juveniles are released from adult competition."The researchers say that armed with findings from this study, scientists need to study how the juvenile starfish respond in the wild to coral scarcity to see if it does trigger a population growth of this cohort.
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April 8, 2020
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https://www.sciencedaily.com/releases/2020/04/200408142730.htm
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New fossil from Brazil hints at the origins of the mysterious tanystropheid reptiles
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A new species of Triassic reptile from Brazil is a close cousin of a mysterious group called tanystropheids, according to a study published April 8, 2020 in the open-access journal
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After the Permian mass extinction, 250 million years ago, reptiles took over global ecosystems. Among the early groups to appear after this extinction event were the tanystropheids, a group of long-necked animals whose lifestyles are still mysterious, but who were nonetheless successful in the Triassic Period. However, the early evolution of this group is poorly understood, as their remains are very rare from the Early Triassic.In this study, De-Oliviera and colleagues describe a new specimen of reptile from Early Triassic rocks of the Sanga do Cabral Formation in southern Brazil. Skeletal comparison indicates this specimen, known from remains of the hind leg, pelvis, and tail, is the closest known relative of tanystropheids. The researchers identified these remains as belonging to a new species, which they named Most tanystropheid fossils are found in Middle to Late Triassic rocks of Europe, Asia, and North America, and often in marine sediments. The presence of
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April 8, 2020
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https://www.sciencedaily.com/releases/2020/04/200408085539.htm
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How does habitat fragmentation affect Amazonian birds?
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The Biological Dynamics of Forest Fragments Project (BDFFP), located near Manaus, Brazil, began in 1979 and is the world's longest-running experimental study of tropical forest fragments. A new paper in
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Louisiana State University's Phil Stouffer, who authored the new paper, led bird research at the Biological Dynamics of Forest Fragments Project from 1991 to 2019. As he describes, studying the changes in bird communities over the forty years following habitat fragmentation led to some surprises. The original plan was to monitor "forest islands" permanently isolated by surrounding cattle pastures, but changes in the Brazilian economy led to the abandonment of the cattle pastures within a few years after their establishment. As trees began to regrow in the areas surrounding the fragments, forest bird species that had initially disappeared began to recolonize the fragments, highlighting the unexpected value of second-growth habitat for rainforest birds. Additional work yielded both good and bad news for fragment-dwelling birds -- for example, non-forest bird species typically didn't invade forest fragments, but even very narrow strips of deforested land could limit the movement of forest-dependent species."The long history of the project allowed us to follow changes in the avifauna rather than just trying to interpret what we saw in any particular slice of time," says Stouffer. "This project was important for stepping away from the idea that habitat fragments are analogous to actual islands -- the modern interpretation is a lot more nuanced, and the recovery of birds in second-growth forest provides encouraging evidence that many rainforest birds can use deforested areas that are allowed to regrow. Our challenge now is to determine under what conditions remnant patches and second growth can support rich Amazonian bird communities." Another issue that the BDFFP hopes to address in the near future is one that didn't even exist when the project began: what has climate change done to Amazonian birds since 1979, and what does the future hold?Working in Manaus once meant being isolated from the global scientific community, but no more -- BDFFP scientists even hosted an international ornithological conference there in 2015. "On the 40th anniversary of the BDFFP, it seems appropriate to summarize what we've learned. It's also important to reflect on how technical advances that we now take for granted in modern fieldwork were incorporated into the project. For example, digital photography helped resolve criteria for determining the ages of Amazonian birds and GPS technology allows us to determine bird locations and movement with high precision, goals unimaginable when I started at the BDFFP," says Stouffer.
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April 8, 2020
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https://www.sciencedaily.com/releases/2020/04/200408085519.htm
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Researchers assess bird flu virus subtypes in China
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The avian influenza virus subtype H16N3 is currently detectable in many countries. To examine the potential threat to humans of H16N3, researchers recently performed an extensive avian influenza surveillance in major wild bird gatherings across China from 2017-2019. The findings are published in
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The investigators isolated two H16N3 subtype influenza viruses that can bind to both human and avian-type cell receptors. They also found evidence that genetic material from other species has been introduced into the H16N3 avian influenza virus, which suggests that it may infect other species and could therefore pose a threat to animal and human health in the future."Consequently, it is necessary to increase monitoring of the emergence and spread of avian influenza subtype H16N3 in wild birds," the authors wrote.
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April 8, 2020
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https://www.sciencedaily.com/releases/2020/04/200408085500.htm
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Exploring why males are larger than females among mammals
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In most animals, females are larger than males, but in most mammals, males are larger than females. A new analysis published in
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In most animals, females are larger than males, but in most mammals, males are larger than females. A new analysis published in The analysis suggests that, alongside sexual selection, natural selection may be an evolutionary driver of sexual size differences in mammals. Males and females may have evolved to differ in size so that they could exploit resources such as food.
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April 7, 2020
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https://www.sciencedaily.com/releases/2020/04/200407215653.htm
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The link between virus spillover, wildlife extinction and the environment
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As COVID-19 spreads across the globe, a common question is, can infectious diseases be connected to environmental change? Yes, indicates a study published today from the University of California, Davis' One Health Institute.
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Exploitation of wildlife by humans through hunting, trade, habitat degradation and urbanization facilitates close contact between wildlife and humans, which increases the risk of virus spillover, found a study published in the journal The study provides new evidence for assessing spillover risk in animal species and highlights how the processes that create wildlife population declines also enable the transmission of animal viruses to humans."Spillover of viruses from animals is a direct result of our actions involving wildlife and their habitat," said lead author Christine Kreuder Johnson, project director of USAID PREDICT and director of the EpiCenter for Disease Dynamics at the One Health Institute, a program of the UC Davis School of Veterinary Medicine. "The consequence is they're sharing their viruses with us. These actions simultaneously threaten species survival and increase the risk of spillover. In an unfortunate convergence of many factors, this brings about the kind of mess we're in now."For the study, the scientists assembled a large dataset of the 142 known viruses that spill over from animals to humans and the species that have been implicated as potential hosts. Using the IUCN Red List of Threatened Species, they examined patterns in those species' abundance, extinction risks and underlying causes for species declines.The data show clear trends in spillover risk that highlight how people have interacted with animals throughout history.Among the findings:Threatened and endangered species also tend to be highly managed and directly monitored by humans trying to bring about their population recovery, which also puts them into greater contact with people. Bats repeatedly have been implicated as a source of "high consequence" pathogens, including SARS, Nipah virus, Marburg virus and ebolaviruses, the study notes."We need to be really attentive to how we interact with wildlife and the activities that bring humans and wildlife together," Johnson said. "We obviously don't want pandemics of this scale. We need to find ways to co-exist safely with wildlife, as they have no shortages of viruses to give us."Study co-authors include Peta Hitchens of the University of Melbourne Veterinary Clinic and Hospital, and Pranav Pandit, Julie Rushmore, Tierra Smiley Evans, Cristin Weekley Young and Megan Doyle of the UC Davis One Health Institute's EpiCenter for Disease Dynamics.The study was supported by funding through the USAID Emerging Pandemic Threat PREDICT program and the National Institute of Health.
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Animals
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April 6, 2020
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https://www.sciencedaily.com/releases/2020/04/200406190508.htm
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Lifestyle trumps geography in determining makeup of gut microbiome
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Apes in U.S. zoos host bacterial communities in their intestinal tracts that are more similar to those of people who eat a non-Western diet than to the gut makeup of their wild ape cousins, according to a new study from Washington University in St. Louis. Further, even wild apes that have never encountered antibiotics harbor microbes with antibiotic resistance genes.
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The findings suggest that contact with people shapes the gut microbial communities, or microbiomes, of gorillas and chimpanzees, and that the gut microbiomes of wild apes provide clues to human-ape interactions that could inform efforts to protect the endangered species. The study also highlights a way to identify new antibiotic resistance genes before they become widely established in bacteria in people, giving researchers time to develop tools to counter such genes before they threaten human health.The study is available online in The gut microbiome supplies us with vitamins, helps digest food, regulates inflammation and keeps disease-causing microbes in check. Antibiotics can change the makeup of the gut microbiome in lasting ways."It's difficult to figure out exactly how antibiotics affect the human gut microbiome when almost everyone is born with bugs that already have antibiotic resistance genes," said senior author Gautam Dantas, PhD, a professor of pathology and immunology, of molecular microbiology, and of biomedical engineering at Washington University School of Medicine. "Wild apes are the closest thing we have to pre-antibiotics humans. Luckily, we got the opportunity to work with two highly respected primatologists."Co-authors Crickette Sanz, PhD, an associate professor of biological anthropology in Arts & Sciences at Washington University, and David Morgan, PhD, a research fellow at the Lester E. Fisher Center for the Study and Conservation of Apes at Lincoln Park Zoo in Chicago and an honorary research scientist at Washington University, study wild chimpanzees and gorillas in a remote area of Nouabalé-Ndoki National Park in the Republic of Congo. The park is managed by the Wildlife Conservation Society and the Congolese government. To learn about the apes' gut microbiomes, Sanz, Morgan and their field teams followed apes in known groups and discreetly collected fecal samples from 18 wild chimpanzees and 28 wild gorillas. The noninvasive sampling method allowed the researchers to collect data on the apes without disturbing them.The samples were stored in liquid nitrogen, carried to the park headquarters, and transported by dugout canoe down the Sangha River and then by truck to Brazzaville, the capital of the Republic of Congo, where they were held in a freezer until they could be shipped to Dantas' lab. The researchers also collected and shipped fecal samples from 81 people who lived on the outskirts of the park.Meanwhile, Dantas and first author Tayte Campbell, PhD -- then a graduate student in Dantas' lab -- arranged to obtain fecal samples from 18 chimpanzees and 15 gorillas living at either the Saint Louis Zoo or the Lincoln Park Zoo. The researchers identified the kinds of bacteria and the antibiotic genes present in the gorilla, chimpanzee and human samples, and compared the results to publicly available data on people who live in the U.S., Peru, El Salvador, Malawi, Tanzania, or Venezuela and follow hunter-gatherer, rural agriculturalist, or urban lifestyles.The gut microbiomes of people whose data was included in the study fell into two groups. In one were hunter-gatherers and rural agriculturalists who typically eat a diet heavy in vegetables and light in meat and fat; this group included the people from the outskirts of the national park in the Republic of Congo. In the second group were urban people who eat a meat-rich Western diet. Wild gorillas and chimpanzees formed a third group distinct from both human groups. But captive apes fell into the first group; they were most similar to people who ate non-Western diets."Chimpanzees are endangered, and Western lowland gorillas are critically endangered; their main threats are habitat destruction, poaching and disease," Sanz said. "Measuring the gut microbiome could be a way to monitor apes' exposure to anthropogenic threats so we can identify areas of concern and develop effective, evidence-based mitigation strategies."The researchers also identified several previously unknown antibiotic resistance genes in the wild apes and people from the Republic of Congo, including one that confers resistance to colistin, an antibiotic of last resort. For now, the genes reside in bacteria harmless to humans. But bacteria have the ability to share genes, so any antibiotic resistance gene could find its way into a more dangerous species of bacteria."Rare sampling opportunities of wild apes like in this study gives us a look into the future," Campbell said. "When we find these novel antibiotic resistance genes in the environment, we can study them and possibly find ways to inhibit them before they show up in human pathogens and make infections very difficult to treat.""It would be very interesting to expand this research across a broader range of conservation contexts, such as commercial logging zones and tourist operations," Morgan added. "With the arrival of human activities and associated anthropogenic disturbances, wild apes may be exposed to antibiotic resistance genes. We don't know much about how antibiotic resistance spreads through natural environments, so that could have implications for human public health that we don't yet understand. That's something we'd like to investigate."
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April 6, 2020
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https://www.sciencedaily.com/releases/2020/04/200406140102.htm
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Innovative birds are less vulnerable to extinction
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Bird species that have the capacity to express novel foraging behaviours are less vulnerable to extinction than species that do not, according to a collaborative study involving McGill University and CREAF Barcelona and published today in
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The researchers found that birds that were able to incorporate new foods into their diet or develop new techniques to obtain food were better able to withstand the environmental changes affecting their habitat, which represent their main threat of extinction.Throughout the years, scientists have noticed numerous examples of these behaviours. Green herons have been repeatedly observed using bread or insects as bait to catch fish. Opportunistic carrion crows have been seen using cars as nut- or seashell-crackers. Great cormorants in New Zealand have been observed coordinating their fishing periods with the movements of commercial ferries in order to take advantage of the strong currents generated by the propellers to catch confused fish.The ability to innovate, a measure of 'behavioural plasticity', has long been thought to render species less vulnerable to the risk of extinction, but it has been difficult to test this thoroughly on a global level.Louis Lefebvre, the senior author of the new study, who teaches in McGill's Biology Department, he has spent the last 20 years combing through the literature, searching for evidence of foraging innovations in the wild. Thanks to the tireless dedication of bird watchers from around the world who have reported these novel behaviours, he has been able to compile a database of over 3,800 bird foraging innovations."The large database we now have has allowed us to test, on almost all bird species of the world, the idea that the more you can change your feeding behaviour, the better you might be able to cope with destruction of your normal habitat," said Lefebvre. "We feel our results are solid, as we have taken into account as many co-variables and possible biases that we could think of."The researchers gathered information about the feeding innovations described in articles published in 204 ornithological journals between 1960 and 2018.They then compared the number of observed innovations of each species with the level of their risk of extinction according to the Red List of the International Union for Conservation of Nature (IUCN). Their modelling showed that extinction risk was reduced in species that displayed innovative behaviours, and as the number of these behaviours increased, extinction risk was reduced further."We long suspected that this relationship between innovation and survival must exist, but now we have been able to verify it quantitatively," says the study's first author, Simon Ducatez, a post-doctoral researcher at McGill University and at CREAF in Barcelona. "We have also been able to verify that the greater the number of innovations described for a species, the greater the probability that its populations are stable or increasing. The result is clear: the greater the innovative capacity, the lower the risk of extinction of the species."Ability to find new food sources no guarantee of survivalThe authors caution that behavioural plasticity only reduces birds' risk of extinction from habitat alteration, and that it does not affect sensitivity to invasive species or overexploitation. The study reveals that the ability to invent new behaviours represents a clear evolutionary advantage for birds coping with the destruction of their habitats, although it is not always a guarantee of survival.Indeed, the type of problem-solving skills that allow birds to face drastic changes in habitat does not seem to work against other types of threats such as over hunting. "It must be taken into account that the species with the greatest capacity for innovation have longer generation times, which makes them more vulnerable to hunting," explains Daniel Sol, researcher at CREAF and the CSIC in Barcelona. "This implies that, unlike what is usually assumed, the ability to innovate protects animals from some but not all of the rapid changes in the environment."This research was supported by funds from the Spanish government and by the Natural Sciences and Engineering Research Council of Canada (NSERC).
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April 6, 2020
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https://www.sciencedaily.com/releases/2020/04/200406092845.htm
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Cold War nuclear bomb tests reveal true age of whale sharks
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Atomic bomb tests conducted during the Cold War have helped scientists for the first time correctly determine the age of whale sharks.
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The discovery, published in the journal Measuring the age of whale sharks (Whale shark vertebrae feature distinct bands -- a little like the rings of a tree trunk -- and it was known that these increased in number as the animal grew older. However, some studies suggested that a new ring was formed every year, while others concluded that it happened every six months.To resolve the question, researchers led by researchers led by Joyce Ong from Rutgers University in New Jersey, USA, Steven Campana from the University of Iceland, and Mark Meekan from the Australian Institute of Marine Science in Perth, Western Australia, turned to the radioactive legacy of the Cold War's nuclear arms race.During the 1950s and 1960s, the USA, Soviet Union, Great Britain, France and China conducted tests of nuclear weapons. Many of these were explosions detonated several kilometres in the air.One powerful result of the blasts was the temporary atmospheric doubling of an isotope called carbon-14.Carbon-14 is a naturally occurring radioactive element that is often used by archaeologists and historians to date ancient bones and artefacts. Its rate of decay is constant and easily measured, making it ideal for providing age estimates for anything over 300 years old.However, it is also a by-product of nuclear explosions. Fallout from the Cold War tests saturated first the air, and then the oceans. The isotope gradually moved through food webs into every living thing on the planet, producing an elevated carbon-14 label, or signature, which still persists.This additional radioisotope also decays at a steady rate -- meaning that the amount contained in bone formed at one point in time will be slightly greater than that contained in otherwise identical bone formed more recently.Using bomb radiocarbon data prepared by Steven Campana, Ong, Meekan, and colleagues set about testing the carbon-14 levels in the growth rings of two long-dead whale sharks stored in Pakistan and Taiwan. Measuring the radioisotope levels in successive growth rings allowed a clear determination of how often they were created -- and thus the age of the animal."We found that one growth ring was definitely deposited every year," Dr Meekan said."This is very important, because if you over- or under-estimate growth rates you will inevitably end up with a management strategy that doesn't work, and you'll see the population crash."One of the specimens was conclusively established as 50 years old at death -- the first time such an age has been unambiguously verified."Earlier modelling studies have suggested that the largest whale sharks may live as long as 100 years," Dr Meekan said."However, although our understanding of the movements, behaviour, connectivity and distribution of whale sharks have improved dramatically over the last 10 years, basic life history traits such as age, longevity and mortality remain largely unknown."Our study shows that adult sharks can indeed attain great age and that long lifespans are probably a feature of the species. Now we have another piece of the jigsaw added."Whale sharks are today protected across their global range and are regarded as a high-value species for eco-tourism. AIMS is the world's leading whale shark research body, and the animal is the marine emblem of Dr Meekan's home state, Western Australia.Drs Ong, Meekan, and Campana were aided by Dr Hua Hsun Hsu from the King Fahd University of Petroleum and Minerals in Saudi Arabia, and Dr Paul Fanning from the Pakistan node of the UN Food and Agricultural Organisation.
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April 3, 2020
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https://www.sciencedaily.com/releases/2020/04/200403104005.htm
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Tooth be told: Earless seals existed in ancient Australia
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A fossilised seal tooth found on a Victorian beach could hold the key to uncovering the history and geography of earless seals that graced Australia's shores three million years ago.
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This prehistoric specimen is only the second earless seal fossil ever discovered in Australia, and proves the country's local fur seals and sea lions were preceded by a group of sea mammals, known as monachines, now long extinct in Australia.The study also highlights the current dangers of climate change to Earth's existing wildlife, with falling sea levels likely to have played a role in the extinction of these ancient seals.The history of this rare specimen was published today (Friday 3 April) in the "This tooth, roughly three million years old, tells a story similar to what occurred in South Africa and South America in the past. Earless monachine seals used to dominate southern beaches and waters, and then suddenly disappeared, with eared seals replacing them," Mr Rule said."Since seal fossils are rare globally, this discovery makes a vital contribution to our understanding of this iconic group of sea mammals."An Australian citizen scientist and amateur fossil collector discovered the tooth while strolling along the beach at Portland, western Victoria.But it wasn't until he donated the fossil to Museums Victoria many years later that it was found to have been a tooth from an extinct group of earless seals.The research team compared the tooth to other pinnipeds -- a group that includes earless seals, fur seals, sea lions and the walrus.They found the tooth possessed characteristics of monachines and shed light on how these seals lived and what they ate."This seal lived in shallow waters close to the shore, likely hunting fish and squid. As monachines cannot use their limbs to walk on land, it would have required flat, sandy beaches when it came ashore to rest," Mr Rule said.Researchers believe drastic changes in the Earth's climate fundamentally altered Australia's environment by eliminating the beaches used by earless seals to rest."These changes in the past have led to the extinction of Australia's ancient earless seals," Dr David Hocking, co-author and Research Fellow in Monash University's School of Biological Sciences, said."Our living fur seals and sea lions will likely face similar challenges as the Earth continues to warm, with melting polar ice leading to rising sea levels."Over time, this may lead to the eventual loss of islands that these species currently rely upon to rest and raise their young."
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April 2, 2020
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https://www.sciencedaily.com/releases/2020/04/200402155727.htm
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Scientists show how parasitic infection causes seizures, psychiatric illness for some
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Think about traffic flow in a city -- there are stop signs, one-way streets, and traffic lights to organize movement across a widespread network. Now, imagine what would happen if you removed some of the traffic signals.
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Among your brain's 86 billion neurons are the brain's own version of stop signals: inhibitory neurons that emit chemicals to help regulate the flow of ions traveling down one cell's axon to the next neuron. Just as a city without traffic signals would experience a spike in vehicle accidents, when the brain's inhibitory signals are weakened, activity can become unchecked, leading to a variety of disorders.In a new study published in The Centers for Disease Control and Prevention estimates that 40 million Americans have varying levels of Toxoplasma infection, although most cases are asymptomatic. Commonly passed to humans via exposure to farm animals, infected cat litter, or undercooked meat, the parasitic infection causes unnoticeable or mild, to flu-like symptoms in most healthy people. But for a small number of patients, these microscopic parasites hunker down inside of neurons, causing signaling errors that can result in seizures, personality and mood disorders, vision changes, and even schizophrenia."After the initial infection, humans will enter a phase of chronic infection. We wanted to examine how the brain circuitry changes in these later stages of parasitic cyst infection," said Michael Fox, a professor at the Fralin Biomedical Research Institute and the study's lead author.The parasite forms microscopic cysts tucked inside of individual neurons."The theory is that neurons are a great place to hide because they fail to produce some molecules that could attract cells of the immune system," said Fox, who is also director of the research institute's Center for Neurobiology Research.Fox and his collaborator, Ira Blader, recently reported that long-term Toxoplasma infections redistribute levels of a key enzyme needed in inhibitory neurons to generate GABA, a neurotransmitter released at the specialized connection between two neurons, called a synapse.Building on that discovery, the scientists revealed that persistent parasitic infection causes a loss of inhibitory synapses, and they also observed that cell bodies of neurons became ensheathed by other brain cells, microglia. These microglia appear to prevent inhibitory interneurons from signaling to the ensheathed neurons."In neuropsychiatric disorders, similar patterns of inhibitory synapse loss have been reported, therefore these results could explain why some people develop these disorders post-infection," Fox said.Fox said the inspiration for this study started years ago when he met Blader, a collaborating author and professor of microbiology and immunology at the University at Buffalo Jacobs School of Medicine and Biomedical Sciences, after he delivered a seminar at Virginia Tech. Blader studied Toxoplasma gondii and wanted to understand how specific strands of the parasite impacted the retina in mouse models.Working together, the two labs found that while the retina showed no remarkable changes, inhibitory interneurons in the brain were clearly impacted by the infection. Mice -- similar to humans -- exhibit unusual behavioral changes after Toxoplasma infection. One hallmark symptom in infected mice is their tendency to approach known predators, such as cats, displaying a lack of fear, survival instincts, or situational processing."Even though a lot of neuroscientists study Toxoplasma infection as a model for immune response in the brain, we want to understand what this parasite does to rewire the brain, leading to these dramatic shifts in behavior," Fox said.Future studies will focus on further describing how microglia are involved in the brain's response to the parasite.Among the research collaborators is Gabriela Carrillo, the study's first author and a graduate student in the Translational Biology, Medicine, and Health Program. Previously trained as an architect before pursuing a career in science, Carrillo chose this topic for her doctorate dissertation because it involves an interdisciplinary approach."By combining multiple tools to study infectious disease and neuroscience, we're able to approach this complex mechanistic response from multiple perspectives to ask entirely new questions," Carrillo said. "This research is fascinating to me because we are exposing activated microglial response and fundamental aspects of brain biology through a microbiological lens."
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April 2, 2020
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https://www.sciencedaily.com/releases/2020/04/200402144430.htm
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The facial expressions of mice
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Researchers at the Max Planck Institute of Neurobiology are the first to describe different emotional facial expressions for mice. Similar to humans, the face of a mouse looks completely different when it tastes something sweet or bitter, or when it becomes anxious. With this new possibility to render the emotions of mice measurable, neurobiologists can now investigate the basic mechanisms of how emotions are generated and processed in the brain.
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Pleasure, disgust, fear -- the facial expressions that reflect these emotions are the same in every human. For example, if we are disgusted by something, our eyes become narrower, our nose wrinkles, and our upper lip distorts asymmetrically. Even newborn babies react with distinct facial expressions when they are sad, happy or disgusted. We also think to recognize feelings in the facial expressions of our pets. In contrast, the faces of other animals can appear expressionless to us. This is wrong, as the Max Planck scientists now show.Using machine vision, the researchers were able to reliably link five emotional states to the facial expressions of mice: pleasure, disgust, nausea, pain and fear were clearly distinguishable for the computer algorithms. They could even measure the relative strength of these emotions.The study shows that the facial expression of a mouse is actually not just a reaction to the environment. It reflects the emotional value of the trigger. "Mice that licked a sugar solution when they were thirsty showed a much more joyful facial expression than satiated mice," explains Nadine Gogolla, who led the study. Meanwhile, mice that tasted a slightly salty solution showed a "satisfied" expression, while a very salty solution led to a "disgusted" face. From these and other experiments, the researchers conclude that, uncoupled from the sensory stimulus, facial expressions actually reflect the inner, individual character of an emotion.Emotions, however, are not simply a reaction to an external stimulus -- they arise through mechanisms in the brain itself. The researchers thus investigated next, how neuronal activity in different brain regions affects the facial expressions. The neurobiologists were able to evoke different emotional facial expressions when they light-activated specific brain areas known to play a role in emotional processing.The main benefit of the discovery of mouse facial expressions is that it is now possible to identify mechanisms giving rise to emotions. This, so far, was precisely the problem: without a reliable measurement of emotions, it has been difficult to study their origins in the brain. "We humans may notice a subtle facial change in the mice, but we can only recognize the emotion behind it with a great deal of experience and can hardly ever determine its intensity," says Nejc Dolensek, the study's lead author. "With our automated face recognition system, we can now measure the intensity and nature of an emotion on a timescale of milliseconds and compare it to the neuronal activity in relevant brain areas." One such brain area is the insular cortex, which is associated with emotional behavior and the perception of emotions in animals and humans.When the scientists measured the activity of individual neurons using 2-photon microscopy and simultaneously recorded the emotional facial expressions of the mouse, something astonishing came to light: individual neurons of the insular cortex reacted with the same strength and at the exactly same time as the mouse's facial expression. In addition, each individual neuron was linked to only one single emotion.These results suggest the existence of "emotion neurons," each reflecting a specific sensation -- at least in the insular cortex. "By recording facial expressions, we can now investigate the fundamental neuronal mechanisms behind emotions in the mouse animal model," explains Nadine Gogolla. "This is an important prerequisite for the investigation of emotions and possible disorders in their processing, such as in anxiety disorders or depression."
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April 2, 2020
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https://www.sciencedaily.com/releases/2020/04/200402144428.htm
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Scientists develop 'backpack' computers to track wild animals in hard-to-reach habitats
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To truly understand an animal species is to observe its behavior and social networks in the wild. With new technology described today (April 2) in
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These high-tech backpacks, which can communicate with each other and ground-based receivers, provided data for the popular study published on Halloween in 2019 showing that vampire bats developed social bonds in captivity that they maintained in the wild.The wireless network developed by a team of engineers, computer scientists and biologists contains functions similar to what we find in our smartphones -- such as motion detection and Bluetooth-style connectivity -- at a fraction of the weight and energy consumption.Keeping the system automated and lightweight was critical to the success of the network to track adult vampire bats, which weigh between 1 and 1.5 ounces and grow to 3½ inches in length. Using devices that can track larger animals, such as those incorporated into harnesses or necklaces, wouldn't work for bats or other small species."Using backpacks on bats saves weight and it also makes sure the sensors fall off easily," said Simon Ripperger, lead author of the paper and a postdoctoral scholar in evolution, ecology and organismal biology at The Ohio State University. "We don't really want the bats to have that burden of additional weight for extended time periods."The sensors often get scratched off in the bats' roost within about two weeks. The researchers retrieve them if they can to recycle the backpacks and recharge and reuse the batteries.Though the study describes the complexity of constructing the network and testing its effectiveness on bats, the system would work for other animals, such as birds, rodents, reptiles and amphibians, Ripperger said. Hence the team's name for the network: Broadly Applicable Tracking System, or BATS.When Ripperger was pursuing his PhD a decade ago, he used a much more primitive system to study bats. He relied on radio-telemetry, sometimes running after the animals, tracking their flight path with an antenna in hand. At best, he might be able to calculate where they were every two minutes over a 30-meter area."It was a time-consuming, exhausting and inaccurate method," he said.With funding from the German equivalent of the National Science Foundation, the grant's principal investigators at the Museum of Natural History in Berlin and a number of German universities assembled an interdisciplinary team and set out to make a better system. Ripperger was a postdoc at the time at the natural history museum, and is still a visiting scientist there.The work took about seven years, with computer scientists writing code from scratch to come up with the highest-performance network possible using ultra-low levels of energy. The capacity of each battery that powers the network amounts to about 5 percent of a AAA battery's capacity.The network consists of the tiny computers -- accelerometers producing data when the bats are moving and proximity sensors to show when they are close to each other -- all encased in each 3D-printed plastic backpack that weighs less than a penny. A series of base stations on the ground pick up signals and record data on bats' social activities and flight trajectories. The components are asleep most of the time, waking up when they receive a signal from another bat and then broadcasting every two seconds."One key advantage of our system is these wake-up receivers. They are in energy-saving mode and only wake up when they receive a signal from another bat, and then they are shouting, 'I'm here, I'm here!' and there's another receiver that comes into full consciousness and exchanges data," Ripperger said. "That's one way we conserve power consumption."Despite the low power, the network produced robust results in various studies of different species of bats. A two-week test in which 50 vampire bats were tagged produced data on almost 400,000 individual meetings. Researchers can download all the data from the system onto their phones in the field.Ripperger described BATS and GPS, the most commonly used method for tracking animals on a grander scale, as highly complementary systems, with BATS able to collect signals in places where GPS cannot."If you want to study social behavior, once a bat enters a cave or tree trunk, a GPS logger doesn't give us information because the signal from the satellite gets interrupted. But inside the roost is where all the social behavior is happening," he said. "These are really two different approaches to studying animal behavior."There is a definite novelty to learning about how vampire bats interact, but the research also has shown remarkable similarities between their social behavior and certain aspects of human relationships. Using this system to tag vampire bats and the cattle they feed on can also help scientists better understand the spread of rabies, Ripperger said. He and colleagues are currently designing a conservation study to tag protected sand lizards living near railway lines in Germany to determine how track maintenance affects their movement.This work was supported by the German Research Foundation, a Smithsonian Institution Scholarly Studies Grant and a National Geographic Society Research Grant.Gerald Carter of Ohio State co-authored the study. Additional co-authors were from the Smithsonian Tropical Research Institute in Panama and the Museum of Natural History, Friedrich-Alexander University Erlangen-Nürnberg, Brandenburg University of Technology, Technische Universität Braunschweig, Paderborn University and the Berlin-Brandenburg Institute of Advanced Biodiversity Research in Germany.
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Animals
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April 1, 2020
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https://www.sciencedaily.com/releases/2020/04/200401130813.htm
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Elephant welfare can be assessed using two indicators
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Across the world, animals are kept in captivity for various reasons: in zoos for education and research, in research facilities for testing, on farms for meat and other products, and in people's homes as pets. Maintaining good animal welfare is not only important for ethical reasons; poor welfare can impact human wellbeing and the economy. But how do we assess how animals are feeling?
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One way to assess animal wellbeing is to look at stress levels. Vets typically use two biological measures of stress: stress hormone levels and white blood cell ratios. In mammals -- including humans -- the most important stress hormone is cortisol. When animals are faced with danger, cortisol is produced to help prepare the body for a challenge. However, if high stress and cortisol are experienced constantly, they can impact an animal's health.In addition to cortisol, scientists can also look at the ratio of two types of white blood cells, heterophils (or neutrophils) and lymphocytes. These cells play an important role in the immune system of mammals, and after animals have experienced a stressful event, their ratio is typically high.Researchers at the University of Turku, Finland, wanted to find out if these two biological measures of stress were correlated and whether animals with high levels of cortisol also had a high heterophil to lymphocyte ratio. They measured cortisol and heterophil to lymphocyte ratios in 120 Asian elephants from a semi-captive population of working timber elephants in Myanmar. The researchers also weighed each elephant, as body weight is a good indicator of general health."Some previous studies have found a positive relationship between stress hormones and heterophil to lymphocyte ratios, while others have found no relationship at all. It was also unclear from previous studies whether these two measures of stress are comparable across individuals of different sex and age, as well as across the seasons. In this population, we found that elephants with higher levels of the stress hormone cortisol also had higher ratios of heterophils to lymphocytes. This was true regardless of sex and age," says Postdoctoral Researcher and the lead author on the first study, Martin Seltmann, from the Department of Biology at the University of Turku.An additional aim of the study was to test if stress hormones and heterophil to lymphocyte ratios are related to body weight in Asian elephants."We did not find a link between the white blood cell ratios and body weight, but elephants with higher levels of stress hormone had a lower body weight, indicating that elevated stress is linked to weight loss. It is useful to see that both a biological marker (cortisol) and physical indicator (body weight) of welfare respond in the same way. This means that both markers can be used to assess the wellbeing of elephants," says researcher Susanna Ukonaho, who participated in the study.In the second study, the researchers investigated whether welfare can also be reliably assessed by observing an animal's behaviour. While elephant specialists may be able to quickly identify behavioural changes, expert knowledge is not always available, so the researchers wanted to test the reliability of behavioural assessments by non-experts. First, they filmed over 100 working Asian elephants undertaking tasks that were either familiar or new to them."The elephants were asked to pick up different types of objects, including objects they had never seen before. This included items such as a plastic bottle, which some elephants were clearly unsure about," says the lead author on the study, Jonathan Webb.The researchers constructed a list of elephant behaviours, which was then used by three volunteers with no prior experience of Asian elephants to collect behavioural data from the films.To assess the reliability of the behavioural data, the researchers looked at how similar the observers' scores were for each film. They also assessed observer consistency by getting the volunteers to score films twice. They found that all three volunteers consistently and reliably identified many elephant behaviours, indicating that even with limited experience, people can reliably monitor elephant behaviour in a way which could improve the quality and safety of working elephant-human relationships.Behavioural markers could therefore be a simple but useful tool for elephant welfare assessment on a larger scale, although the researchers caution that we still need to know how different behaviours are linked to biological measures of stress.The relationship between different measures of animal welfare is often complex, but the findings of these two studies show that, at least when working with elephants, caretakers have several options for assessing the wellbeing of their animals. These options will not only facilitate the caretakers' work, but also help elephants to live better and healthier lives.
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Animals
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April 1, 2020
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https://www.sciencedaily.com/releases/2020/04/200401130809.htm
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About the distribution of biodiversity on our planet
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Since Charles Darwin, biologists have been using the so-called "biotic interactions" hypothesis to explain, at least in part, why the tropics around the equator are so species rich. The hypothesis focuses on the importance of interactions between species for biodiversity. The geneal idea is that species interactions increase towards the species-rich equator. Such interactions may include interactions such as between parasites and host, or between a predator and its prey. The intuitively appealing hypothesis is: The stronger the interactions between species, the faster evolutionary change, thus resulting in increased species diversity. Strong species interactions should further help maintain a high level of biodiversity. Testing this long-standing hypothesis has proven extremely difficult in the past, and the results from past studies aiming to test the "biotic interactions" hypothesis are mixed.
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A new publication in To measure the interaction strength between large fish predators and small prey fish, the scientists analyzed four large data sets from pelagic (open ocean) longline fishing spanning all four major ocean basins (East and West Pacific, Atlantic, Indian Ocean). These data were used to infer how many predatory fish were caught per bait -- a natural prey such as a mackerel or sardine. The researchers evaluated the catch of a fish predator as an attack by a predatory fish on its prey and hence, as an interaction between two species. "This investigation was only possible due to this extraordinary data set. The full data set spans the entire planet and records over 900 million catches of fish predators by longline fisheries over the past 55 years," comments Marius Roesti. The researchers then inferred where predatory fish bite most frequently and compared these results with the diversity of fish species.The study found that predation by large fish is stronger at latitudes in the temperate zone than near the equator. "The latitudes with the relatively highest number of captured predators are in or near the temperate zone, and not near the equator. This result is generally true for all ocean basins and the entire period under investigation," says Roesti. Predation then decreased again towards the poles. Furthermore, the study shows that fish species richness is not highest where predation is strongest.In a nutshell: Pelagic fish predation is not strongest near the equator, but in the temperate zone. In turn, fish species richness peaks at the equator. These results contradict the general idea of the "biotic interactions" hypothesis, at least for pealgic fish predation.
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Animals
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April 1, 2020
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https://www.sciencedaily.com/releases/2020/04/200401130754.htm
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Surprising hearing talents in cormorants
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Many aquatic animals like frogs and turtles spend a big part of their lives under water and have adapted to this condition in various ways, one being that they have excellent hearing under water.
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A new study shows that the same goes for a diving bird, the great cormorant.This is surprising because the great cormorant spends most of its time out of the water. It is the first time we see such extensive hearing adaptations in an animal that does not spend most of its time under water, says biologist Jakob Christensen-Dalsgaard, University of Southern Denmark.Researchers are increasingly paying attention to the living conditions of animals living in or near the oceans.Oceans are no longer the quiet habitats they used to be. Human activities produce noise -- examples are ship traffic, fishing and windmill constructions, and this noise may pose a threat to the oceans' animals."We need more knowledge about how animals are affected by this noise -- does it impair their hearing or their hunting and fishing abilities? We have studied the effect on whales for some time now, but we don't know very much about diving birds. There are many vulnerable animal species living or foraging at sea, that may be negatively affected by human noise," says Jakob Christensen-Dalsgaard."Even though the great cormorant is not an aquatic animal, it does frequently visit the water columns, so it makes sense that it, too, has adapted its ears for hearing under water," Jakob Christensen-Dalsgaard says about the new study.Whereas the great cormorant spends about 30 seconds foraging under water in active pursuit of prey, approximately 150 other species of diving birds spend up to several minutes in pursuit of fish and squid.Foraging under water is challenging for the sensory apparatus of the birds, however, and for most birds, their visual acuity under water is no better than that of humans. So, the birds may use other sensory modalities.We know very little about birds' hearing under waterApart from a few behavioral studies, the hearing of birds under water is unknown.Previously, researchers from University of Southern Denmark, have documented that great cormorants and gentoo penguins respond to sound under water, but this is the first study of the physiology of underwater hearing in any bird.The study shows that the cormorant ear has been specialized for underwater hearing.To study hearing of the cormorant in air and under water the scientists measured auditory evoked responses and neural activity in response to airborne and underwater sound in anesthetized birds.The neural responses to airborne and underwater sounds were measured using electrodes under the skin. In this way, the scientists could measure hearing thresholds to sound in air and under water.Thresholds in water and air proved to be similar, with almost the same sensitivity to sound pressure in the two media. This is surprising, because similar sound pressures in air and water means that the threshold sound intensity (the energy radiated by the sound wave) is much lower in water, so the ear is more sensitive to underwater than to airborne sound."We found anatomical changes in the ear structures compared to terrestrial birds. These changes may explain the good sensitivity to underwater sound. The adaptations also may provide better protection of the eardrums from the water pressure," says Jakob Christensen-Dalsgaard.But there is -- as always in Nature -- a cost to these benefits:Their hearing in air is not as sensitive as in many other birds. Their eardrums are stiffer and heavier.The cormorant eardrum shows large vibrations in response to underwater sound, so the sensitivity likely is mediated by the eardrum and middle ear.Underwater eardrum vibrations and anatomical features of the cormorant ear are similar to features found in turtles and aquatic frogs, that also appear to be specialized for underwater hearing.The data suggest convergent modifications of the tympanic ear in these three distantly related species, and similar modifications may be found in other diving birds.
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Animals
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April 1, 2020
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https://www.sciencedaily.com/releases/2020/04/200401130752.htm
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Tiny fly from Los Angeles has a taste for crushed invasive snails
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As part of their project BioSCAN -- devoted to the exploration of the unknown insect diversity in and around the city of Los Angeles -- the scientists at the Natural History Museum of Los Angeles County (USA) have already discovered numerous insects that are new to science, but they are still only guessing about the lifestyles of these species.
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"Imagine trying to find a given 2 mm long fly in the environment and tracking its behavior: it is the smallest imaginable needle in the largest haystack. So when researchers discover new life histories, it is something worth celebrating," explains Dr. Brian Brown, lead author of a recent paper, published in the scholarly open-access However, Brown and Maria Wong, former BioSCAN technician, while doing field work at the L.A. County Arboretum, were quick to reveal a curious peculiarity about one particular species discovered as part of the project a few years ago. They successfully lured female phorid flies by means of crushing tiny, invasive snails and using them as bait. In comparison, the majority of phorid flies, whose lifestyles have been observed, are parasitoids of social insects like ants.Within mere seconds after the team crushed tiny invasive snails (Oxychilus draparnaudi), females representing the fly species Megaselia steptoeae arrived at the scene and busied themselves feeding. Brown and Wong then collected some and brought them home alive along with some dead snails. One of the flies even laid eggs. After hatching, the larvae were observed feeding upon the rotting snails and soon they developed to the pupal stage. However, none was reared to adulthood.Interestingly, the host species -- used by the fly to both feed on and lay eggs inside -- commonly known as Draparnaud's glass snail, is a European species that has been introduced into many parts of the world. Meanwhile, the studied fly is native to L.A. So far, it is unknown when and how the mollusc appeared on the menu of the insect.To make things even more curious, species of other snail genera failed to attract the flies, which hints at a peculiar interaction worth of further study, point out the scientists behind the study, Brown and Jann Vendetti, curator of the NHM Malacology collection. They also hope to lure in other species of flies by crushing other species of snails.
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Animals
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March 31, 2020
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https://www.sciencedaily.com/releases/2020/03/200331130023.htm
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Needing a change? Researchers find GABA is the key to metamorphosis
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Metamorphosis, or a dramatic change in physical appearance, is a normal part of the life cycle of many animals, carried out to take advantage of different ecological niches. Yet the process of metamorphosis -- how a caterpillar becomes a butterfly, or a tadpole transforms into a frog -- is not well understood and has only been studied in a small number of species.
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In a study published this week in Ciona are some of the closest living relatives of vertebrates. Starting life as tadpole-like larvae, Ciona undergo a metamorphosis into vase-shaped adults that is triggered by their attachment to a solid surface."Ciona have organs called adhesive papillae that sense when the animal attaches to a surface, triggering metamorphosis," explains Professor Yasunori Sasakura, senior author. "The adhesive papillae contain sensory neurons that transmit signals to the rest of the body, suggesting that the nervous system plays an essential role in initiating metamorphosis."To investigate the role of the nervous system in metamorphosis, the researchers treated Ciona larvae with various neurotransmitters, among which only GABA induced the physical changes associated with maturation. Upon blocking the genes required for GABA synthesis, transport, and maturation, the researchers observed decreased induction of metamorphosis, confirming they had found the right regulatory molecule.GABA, or gamma aminobutyric acid, is one of the main neurotransmitters in mammals. It is usually thought of as an inhibitory molecule because it blocks certain signals in the brain, decreasing nervous system activity. Interestingly, however, the researchers found that this was not the case in Ciona metamorphosis."Using expression analysis and gene knockout/knockdown assays, we showed that GABA activates the neurons expressing gonadotropin-releasing hormone (GnRH), which is essential for reproductive maturation in vertebrates," says Professor Sasakura. "Knocking out the genes encoding GnRH showed that it is essential for metamorphosis in Ciona larvae and confirmed its place as the downstream component of GABA-mediated regulation."Further experimentation showed that while larvae lacking GnRH could not carry out the initial steps of metamorphosis, they did exhibit normal adult organ growth. In contrast, no adult organ growth was observed in GABA mutants, suggesting that GABA is essential for all metamorphic events.The researchers now hope to understand how the GABA-GnRH pathway causes the dramatic physical changes that occur during Ciona metamorphosis and, given the wide conservation of these molecules among animals, to explore whether the GABA-GnRH mechanism plays a role in the metamorphosis of other animal species.
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Animals
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March 31, 2020
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https://www.sciencedaily.com/releases/2020/03/200331130017.htm
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Preservation of testicular cells to save endangered feline species
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A research team at the German Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW) developed a method to isolate and cryopreserve testicular cells. This will allow the safekeeping and biobanking of gametes and other cells of the male reproductive tract of threatened or endangered feline species. The findings have been published in the scientific journal "
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Cryopreservation in liquid nitrogen at -196°C is a common procedure to store germ cells (sperm and eggs) and embryos but can be damaging to cells. Initially, the team tested two different "freezing speeds," as the extent of freezing damage strongly depends on the speed of temperature reduction during the freezing process. To ensure that germ cells and embryos are functional again after thawing, cryoprotectants are usually applied before freezing. These must penetrate the cells before the temperature is lowered in order to prevent or weaken the formation of ice crystals inside the cells and thus prevent damage. Since the most commonly used cryoprotectants are cytotoxic at higher concentrations, the scientists tested two different concentrations for freezing.Whereas usually a cryoprotectant penetrates individual cells relatively quickly, cells inside the tissue of an organ are difficult to reach by the cryoprotectant. In this study, the testicular tissue was therefore not preserved in small pieces but -- after dissolution of the tissue complex -- as a cell suspension so that the cryoprotectant could penetrate individual cells faster. This method has already been successfully used in some mammalian species and was adapted by scientists at the Leibniz-IZW for the conservation of feline testicular cells. To dissolve the tissue complex as gently as possible, the Leibniz-IZW researchers combined the mechanical preparation steps with the interruption of cell to cell contacts using a cocktail of enzymes."A particular problem in cryopreserving tissue or cell suspensions is the assessment of cell recovery after thawing. Ultimately, cell functionality can only be achieved in long-term cell culture experiments. However, in order to optimise the freezing process in the short term, we used two methods to assess the viability of the cells," explains Mohammad Bashawat, scientist at the Leibniz-IZW. Using fluorescent reporter molecules, the lower concentration of cryoprotectant combined with a slow freezing speed was clearly the most beneficial method. About 45 % of cryopreserved testicular cells of castrated domestic cats were vital again after thawing. Comparably good results were obtained in two pilot studies with testicular cells of an Asian golden cat and a cheetah. The Leibniz-IZW research team sees this as an important step towards preserving the germ lines of valuable animals for future applications in the context of species conservation and the maintenance of diversity in their genomes.Of the 39 cat species that are currently extant, 25 are on the "Red List" of the International Union for the Conservation of Nature (IUCN) with a status varying from "vulnerable" to "critically endangered." Measures to enhance reproduction are becoming increasingly important for the conservation of genetic diversity in these species. These measures include cryopreservation of germ cells and artificial insemination. The testes of males which died or had to be euthanised contain stem cells and numerous immature precursors of male germ cells. In future, these could hopefully be matured into spermatozoa during spermatogenesis in the "test tube," as has previously been shown by research groups working with mice and humans. In order to have testicular cells of feline species available for such future projects, their cryopreservation is the method of choice, as this allows an almost unlimited storage of this valuable gene reserve ("cryobanking"). This is especially true for individuals which cannot supply functionally "mature" sperm because of their age or state of health.
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March 31, 2020
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https://www.sciencedaily.com/releases/2020/03/200331092715.htm
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When warblers warn of cowbirds, blackbirds get the message
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This is the story of three bird species and how they interact. The brown-headed cowbird plays the role of outlaw: It lays its eggs in other birds' nests and lets them raise its young -- often at the expense of the host's nestlings. To combat this threat, yellow warblers have developed a special "seet" call that means, "Look out! Cowbird!"
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In a new study, researchers at the University of Illinois at Urbana-Champaign report that red-winged blackbirds respond to the seet call as if they know what it means."Does this mean red-winged blackbirds understand that the call is specific to cowbirds or are they just responding to a general alarm?" said graduate student Shelby Lawson, who led the study with Mark Hauber, a professor of evolution, ecology and behavior at the U. of I. The researchers sought to answer that question by playing back the calls of several bird species in warbler and blackbird territories to see how the birds reacted.They report their findings in the journal "We know that eavesdropping on the calls of other species is common across the animal kingdom," Lawson said. "Birds do it. Mammals do it. There are studies of different primates that do it -- and even birds that listen in when they do."In the rainforests of Ivory Coast, for example, tropical birds known as hornbills have deciphered some of the calls of the Diana monkey. The hornbills ignore the monkeys' alarm calls for ground predators, which are no threat to the birds, but heed the monkeys' calls for hawks, which are predators of hornbills."Chickadees have very general alarm calls that we now know signal the size of different predators," Lawson said. "A lot of birds will listen to these calls and respond based on the danger posed to them. There's also a study of nuthatches listening to chickadee calls."But all these studies look at alarm calls directed at predators that can kill adult animals, Lawson said."Yellow warblers are the only bird we know about that has developed a specific call for a brood parasite," she said. "When they see a brown-headed cowbird, yellow warblers will make the seet call and then females that hear the call will go back to their nest and sit on it tightly to protect their eggs. They only do this with cowbirds. They don't seet at predators or anything else."In an earlier study, Lawson and her colleagues were playing audio of seet calls to study warbler behavior when they noticed that red-winged blackbirds were also responding aggressively to the calls. This prompted the new study.To learn what the red-winged blackbirds understood about the calls, the researchers played a variety of bird calls in red-wing and yellow warbler territories and watched how the birds responded. They found that the red-winged blackbirds responded identically to the seet calls, the sound of cowbird chatter and blue jay calls -- all of which signal a threat to their nests."They responded very aggressively to these calls, more so than they did to the warbler 'chip' call, which is just a general antipredator call," Lawson said. When red-wings heard the warblers seeting, they flew close to the loudspeaker and looked around for the threat, she said.When red-winged blackbirds see any kind of predator in their territory, they swoop at it and dive bomb it. Male red-wings have so many mates in so many nests that they must defend a wide territory from interlopers and threats, Lawson said. This is why red-winged blackbirds are known as the "knights of the prairie."In defending their own nests from predators, they end up helping out other bird species -- in particular, yellow warblers. Previous research shows that yellow warblers that nest near red-winged blackbirds suffer less from cowbirds laying their eggs in their nests.The warblers also appear to help the blackbirds by warning of nest predators, the researchers said."We found that the red-winged blackbirds that nest really close to the warblers respond more strongly to the seet calls than those that nest far away," Lawson said.The researchers have more work to do to determine whether the blackbirds understand that the seet call means "cowbird," specifically, or if it is just interpreted as a general danger to the nest. In a future study, the researchers will play the seet call to re-wings at the end of the nesting season to see if the blackbirds respond as aggressively to the sound after their eggs have hatched. Yellow warblers stop making the seet call when their nestlings are secure and too old to be bothered by cowbirds."This is the first report of a bird eavesdropping on another species' warning of a brood parasite," Hauber said. "We don't yet know if the red-winged blackbirds understand that the warning is specific to cowbirds, but it's obvious they understand that the call represents a threat to the nest -- and that benefits them."The National Geographic Society supports this research.
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Animals
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March 31, 2020
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https://www.sciencedaily.com/releases/2020/03/200331093110.htm
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Bison in northern Yellowstone proving to be too much of a good thing
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Increasing numbers of bison in Yellowstone National Park in recent years have become a barrier to ecosystem recovery in the iconic Lamar Valley in the northern part of the park, according to a study by Oregon State University scientists.
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In the valley, foraging by bison exerts 10 times the environmental pressure of elk, historically the area's dominant herbivore -- that's a problem because bison are powerful "ecosystem engineers."Large numbers of bison disrupt species distribution across shrub steppe and grasslands. They do so via what they eat, trample and rub their horns and bodies on -- i.e., tree bark. Thus, bison have tremendous capacity to limit the structure and composition of woody plant communities.That in turn affects the character of riparian plant communities, as well as stream and river channels, altering habitats and food webs for terrestrial and aquatic wildlife species alike.The findings were recently published in the journal In the United States, the range of the bison originally ran from east of the Appalachians to west of the Rocky Mountains, with most of them living on their evolutionary home base, the Great Plains.Their numbers once totaled an estimated 30 million, perhaps more, said OSU College of Forestry researcher Bob Beschta, corresponding author of the Lamar Valley ecosystem study."The bison population sharply decreased in the 1800s and their distribution became more constricted as European-Americans extended their influences westward across the country," Beschta said.By the 1830s, there were no bison east of the Mississippi River or on the Snake River Plains. Fifty years later, the Plains bison were close to extinction."Several small herds were reported near Yellowstone National Park just before the park's establishment in 1872, perhaps driven there by hunting pressure on the Great Plains," said study co-author Bill Ripple, also of the OSU College of Forestry. "Poaching of bison occurred after park establishment, until 1901, at which time only 22 bison were present in the park."In 1907, more than 60 bison from a growing herd in the Mammoth Hot Springs area of Yellowstone were transferred to the Lamar Valley. By 1925 the Lamar Valley bison herd had grown to more than 750, necessitating population reduction measures. Culling of the Lamar herd continued for more than four decades.Meanwhile, National Park Service managers became increasingly concerned about the environmental effects of Rocky Mountain elk in the park's northern range, which includes the Lamar Valley, and began to cull them as well. In the early 1900s both gray wolves and cougars, predators that influenced elk behavior and density, had been extirpated.In the absence of these predators, combined with hunting prohibitions inside the park, wintering elk populations began to heavily browse young woody plants in the northern range, which led to a decrease in "recruitment" -- the growth of seedlings and sprouts into tall saplings and trees -- of quaking aspen, cottonwood, willow, thinleaf alder and berry-producing shrubs.Culling of both elk and bison stopped amid public and congressional concerns in 1968, at which time there were about 4,000 elk and 100 bison in the northern range. Within two decades, those numbers had increased to 20,000 and 1,000.Cougars returned to the northern range in the 1980s, followed by wolf reintroduction a decade later, thus restoring the park's guild of large predators."Changes in elk behavior were observed shortly after the return of wolves" Beschta said. "And, with predation pressure from wolves, cougars and grizzly bears, a degraded winter range, and human hunting of elk that wintered outside the park, annual counts of the northern range elk herd began to decrease from their historical highs in the 1990s."In the years since wolf reintroduction, the northern range's elk population has declined to about 5,000, with most them wintering outside the park. Bison numbers inside the park, on the other hand, have increased to a historical high of about 4,000.Deciduous woody plant species in many areas of the northern range started to increase in establishment, young plant height, diameter growth, recruitment, canopy cover and berry production -- all associated with reduced browsing pressure from elk."But in portions of the northern range, like the Lamar Valley where bison are common, woody vegetation has continued to decline," Ripple said. "We hypothesized that was because of the bison. We also hypothesized that bison, via the suppression of riparian vegetation and trampling of streambanks, may be increasingly influencing the channel of the Lamar River and tributary streams that cross the valley floor."Photo analysis indicated a near complete loss of willow-dominated riparian communities for at least some parts of the Lamar River and the West Fork of Rose Creek."And the roughly 7.5 hectares of aspen stands that were present on the valley floor in 1954 had diminished to one-tenth of a hectare by 2015, representing a 99% loss in the cover of overstory aspen trees," Ripple said. "The rapid increase in bison numbers in recent years suggests the park's large carnivore guild may be incapable of controlling bison populations. And prey switching by wolves -- from elk to bison -- looks unlikely to provide a stabilizing effect on bison populations."The researchers stress that the long-term recovery of the Yellowstone bison herd has been a major conservation success story and, as one of the few remaining herds that has not hybridized with cattle, Yellowstone bison "are an invaluable conservation resource.""However, increased bison numbers over the last two decades appear to have come at a major ecological cost to the biological diversity and functioning of the riparian ecosystems in the Lamar Valley," Beschta said. "Even to a casual observer there are clear indicators of highly altered ecological conditions across the Lamar Valley, including a high density of bison trails, wallows and scat. High bison numbers have been an effective agent for accelerating the biological and physical modification of the valley's seeps, wetlands, floodplains, riparian areas and channels, trends that had begun decades earlier by elk."Ecosystem simplification -- a loss of biodiversity, landscape complexity and ecological integrity -- is well underway, much like as is associated with high levels of domestic livestock use in areas of the mountain west, Beschta added."The ongoing environmental effects of bison would have to be significantly reduced in order to restore biologically diverse communities dominated by willows, cottonwoods and aspen," Beschta said. "As park administrators make management decisions that affect ungulate densities and distributions in Yellowstone, as well as those in other parks and reserves with high ungulate densities, our findings indicate a need to take into account the often wide range of ecological effects that abundant large herbivores can have on terrestrial and aquatic ecosystems."The Ecosystem Restoration Research Fund and the National Science Foundation supported this research. J. Boone Kauffman and Luke E. Painter of the OSU Department of Fisheries and Wildlife were coauthors on the study.
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March 30, 2020
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https://www.sciencedaily.com/releases/2020/03/200330130000.htm
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Ecosystem services are not constrained by borders
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What do chocolate, migratory birds, flood control and pandas have in common? Many countries benefit from ecosystem services provided outside their nations. This can happen through economic relationships, biological and geographical conditions, but we hardly know how and where these ecosystem service flows occur. Scientists at the Helmholtz Centre for Environmental Research (UFZ) and the German Centre for integrative Biodiversity Research (iDiv) show in a recent study, published in the journal
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"Ecosystem services are not constrained by borders," says Prof. Aletta Bonn, who works on ecosystem services at the UFZ and iDiv. "For example, one country benefits from agricultural products originating from other continents or flood protection provided by floodplains in a neighbouring country." These close links between distant regions arising from ecosystem services are known as telecoupling. Understanding these flows can help to recognise the value of intact nature, identify global drivers of biodiversity loss or soil erosion in distant regions, and develop measures for more sustainable management. "It is important to understand the interlinkages and the environmental costs caused by domestic consumption of ecosystem services in other countries," says Aletta Bonn. "This information can then be used in political decisions, such as fair trade standards, environmentally and socially acceptable certification, and financial compensation measures." But how can ecosystem service flows be identified, quantified and ultimately balanced between countries? The researchers investigated these issues in their recent study. As part of this, they examined the extent to which Germany uses ecosystem services that are provided in other countries."In previous work, we had already developed a conceptual framework for quantifying interregional ecosystem service flows," says Aletta Bonn. "Here, we differentiated between four types of flows which were examined for Germany in more detail." The scientists assessed trade flows using cocoa imports as an example and their impact on biodiversity in the producing countries. "It turns out that approximately 85 percent of imported cocoa comes from only five mainly West African countries -- Ivory Coast, Ghana, Nigeria, Cameroon and Togo. Significant impacts on biodiversity are considered for Cameroon and Ecuador due to cocoa trade with Germany," says Dr. Janina Kleemann, former UFZ researcher and now at Martin Luther University Halle-Wittenberg. In the "migratory species" category, the scientists investigated the importance of migratory birds for German agriculture. "Our results indicate that Africa's tropical and subtropical climate zones provide a habitat for the majority of migratory bird species that make an important contribution to pest control in German agricultural landscapes," explains Janina Kleemann. Ecosystem services associated with flood protection are assigned to the "passive biophysical flow" category. Here, the researchers concluded that Germany benefits by almost two-thirds from flood regulation provided in other countries' floodplains, and in return also exports around 40 percent flood regulation to downstream neighbouring countries such as the Netherlands. In the "information flows" category, the loan of a Chinese giant panda to Berlin Zoo served as a case study. The research team highlighted the political, economic, scientific and cultural aspects of this exchange for the relationship between Germany and China."To place our study on a sound basis, we collaborated in an interdisciplinary, international team of ecologists, economists, geographers and social scientists," explains Aletta Bonn. The UFZ study is one of the first studies to identify, systematically quantify and assess several interregional ecosystem service flows for a specific country using examples. Awareness and understanding of these flows is the first step towards fairly balancing ecosystem services use and sustainable resource management. "When we know how and to what extent we influence global biodiversity with our consumption patterns and international trade, we can make better decisions regarding individual and national consumption of resources and develop adequate measures for sustainable management," says Aletta Bonn. "Our study clearly demonstrates that countries such as Germany bear a global responsibility to protect and conserve biological diversity worldwide."
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Animals
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March 30, 2020
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https://www.sciencedaily.com/releases/2020/03/200330110339.htm
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How animals understand numbers influences their chance of survival
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While they can't pick out precise numbers, animals can comprehend that more is, well, more. From birds to bees and wolves to frogs, animals use numbers to hunt, find a mate, return to their home, and more -- and researchers believe that this ability to process and represent numbers, known as numerical competence, plays an important role in how animals make these decisions and influences an animal's chance of survival. In a Review publishing March 30 in the journal Trends in Ecology and Evolution, Andreas Nieder, a neurobiologist at the University of Tuebingen, Germany, explores the current literature on how different animal species comprehend numbers and the impact on their survival, arguing that we won't fully understand the influence of numerical competence unless we study it directly.
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"Interestingly, we know now that numerical competence is present on almost every branch on the animal tree of life," says Nieder, who works with different animal species to explore how trained animals discriminate and represent numbers as well as how numbers are represented in the brain. "Different groups of animals obviously developed this trait independently from other lineages and that strongly indicates that it has to be of adaptive value. So the capability to discriminate numbers has to have a strong survival benefit and reproduction benefit."Honeybees, for instance, can remember the number of landmarks they pass when searching for food in order to find their way back to the hive. "The last common ancestor between honeybees and us primates lived about 600 million years ago," he says. "But still, they evolved numerical competence that, in many respects, is comparable to vertebrae numerical competence."This can also be seen in animals choosing a larger amount of food over a small amount or in animals forming hunting alliances. Wolves are more likely to hunt successfully if they have the right number of wolves in their pack for the size of their prey: with prey like elk and moose, only around six to eight wolves are needed, while hunting bison requires a pack of nine to thirteen. Their prey also use this concept to protect themselves from predators -- elk tend to live in smaller herds, which rarely have encounters with wolves, or gather in large herds to reduce the chance of any individual becoming prey. "So obviously they are assessing the number of individuals in their groups for their everyday life situations," Nieder says.Furthermore, it has been shown that numerical competence even plays a role in attracting a mate. For example, male frogs sing "advertisement" calls to attract females. The females, listening for the complexity of their calls, choose the male that sings the most "chucks" in their mating call. Even once they've attracted a mate, species like the mealworm beetle and the cowbird use numerical competence to increase the likelihood of having offspring.Despite these many examples of numerical competence in animals, this subject has not gotten many first-hand studies. "Many of these behavioral findings in the wild have usually been collected as by-products or accidental findings of other research questions," says Nieder.Researchers do have some sense of the rules that govern numerical competence in animals, including that they count approximately rather than specifically and that two numbers need to be more different for them to tell them apart as those numbers get bigger -- and it does seem apparent that those abilities are adaptive. However, Nieder argues that more research needs to be done to fully understand the selective pressures and fitness payoffs of numerical competence.He also says that it is important to better understand the laws of perception and the underlying cognitive and neural machinery that goes into numerical competence, in order to understand how it drives fitness-related decisions. To that end, in the next year, Nieder and his lab will move toward researching how the brain and neurons process numbers in animals. "I hope I can encourage behavioral ecologists to specifically explore numerical competence in the wild, and, in doing so, also open new research fields," he says.
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Animals
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March 30, 2020
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https://www.sciencedaily.com/releases/2020/03/200330093431.htm
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Where lions roam: West African big cats show no preference between national parks, hunting zones
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West African lions are a critically endangered subpopulation, with an estimated 400 remaining and strong evidence of ongoing declines.
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About 90% of these lions live in West Africa's largest protected area complex, the W-Arly-Pendjari. The WAP Complex includes five national parks and 14 hunting concessions across roughly 10,200 square miles in Burkina Faso, Niger and Benin.Given that wildlife protection is one of the main purposes of a national park, you might expect West African lions to favor life inside park boundaries, rather than within the privately managed hunting concessions that surround the parks. After all, lions tend to shun people, and human pressures are higher in hunting areas than in the parks.But a new University of Michigan-led camera survey of West African lions -- believed to be the largest wildlife camera survey ever undertaken in West Africa and the first carried out within WAP Complex national parks and hunting concessions -- found that West African lions show no statistically significant preference between the parks and trophy-hunting areas.The findings, scheduled for publication March 30 in the "Our results suggest habitat quality in national parks is inadequate, leading to a lack of preference in lions despite lower human pressures," said doctoral student Kirby Mills of U-M's Applied Wildlife Ecology (AWE) Lab, lead author of the study.The researchers suspect that the lure of plentiful water, high-quality habitat and abundant prey on hunting properties outweigh the lions' natural avoidance of humans. Revenues from trophy hunting pay for enhanced infrastructure such as irrigation systems and solar-powered pumps at watering holes, as well as added patrol staff.At the same time, under-resourced national parks struggle to deal with degraded wildlife habitat, poachers, inadequate staffing and displacement of wildlife by livestock, which are permitted within the parks."We recommend prioritizing the reduction of habitat degradation in the parks and increasing water availability to increase suitable habitat for lions and their prey," said Mills, who conducted the study for her master's thesis at the U-M School for Environment and Sustainability. "But at the same time, we recognize that management interventions at a large scale require economic resources unavailable to park managers in WAP, an incongruity prolific throughout the range of African lions."The study's senior author is Nyeema Harris, an assistant professor in the U-M Department of Ecology and Evolutionary Biology and director of the AWE Lab. Harris designed the project and led the fieldwork with an international team that included government employees and students from Burkina Faso and Niger.In the U-M-led study, 238 motion-activated digital cameras were deployed across 5,000 square miles in three WAP Complex national parks and 11 of the hunting concessions. The fieldwork was conducted from February through June in 2016, 2017 and 2018.Some 1.7 million images were captured during that time, but West African lions triggered the shutter just 96 times, reflecting the critically endangered feline's scarcity. The cameras were programmed to rapid-fire three to five frames when triggered, so the total number of lion images is 360.The camera data were used in two types of mathematical models -- occupancy models and structural equation models. The occupancy models allowed the researchers to calculate the probability that an animal used a given space, while the SEM models enabled them to disentangle the relative effects of environmental, ecological and anthropogenic factors influencing space use by West African lions.The researchers found that lion occupancy was largely driven by prey availability, which in turn was shaped by ecological and environmental variables -- such as water availability and habitat diversity -- that scored higher in hunting concessions than in national parks.Contrary to the researchers' expectations, the WAP Complex lions showed no discernable preference between national parks and hunting zones. The U-M-led study provides the first estimate of West African lion occupancy using camera-trap data."We hypothesize that ecological cues indicating high-quality habitat, such as plentiful water and available prey, are mitigating the expected avoidance response to the increased human pressures and competitor activity in hunting concessions," Harris said."Because the lions rely heavily on prey, managers may be able to manipulate the distribution of prey within WAP to directly influence spatial distributions of lions and indirectly reduce human-lion conflict.Stretching across three countries in the West African savanna belt, the WAP Complex is a UNESCO World Heritage site and is described by the U.N. agency as "a refuge for wildlife species that have disappeared elsewhere in West Africa or are highly threatened."Trophy hunting is permitted in all of the WAP Complex concessions but is illegal in the five national parks and in Niger's Tamou game reserve, which is part of the protected area complex. The lions are known to feed on several species of antelope, as well as savanna buffalos and warthogs. Predators that compete with the lions for food include spotted hyenas and leopards.West African lions are categorized as critically endangered in the International Union for Conservation of Nature's Red List of Threatened Species. In its 2015 assessment, the IUCN states that the West African lion subpopulation is estimated at just above 400 animals, with fewer than 250 mature individuals.West African lions are smaller than, and genetically distinct from, other African lions. They form smaller prides, and the males have little to no mane."This population continues to decline," the IUCN assessment states. "Further deterioration of the last protected areas harbouring lions in West Africa will likely lead to the local extinction of the species."
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Animals
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March 26, 2020
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https://www.sciencedaily.com/releases/2020/03/200326144423.htm
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What can be learned from the microbes on a turtle's shell?
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Research published in the journal
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It is hoped that these findings can be applied to support the conservation of turtles. Previous research has shown that a diverse microbiome can protect animals against infections.The research aimed to understand how the microbiome -- a complex community of micro-organisms -- varies around the body of Krefft's river turtles. Samples were assessed from inside the mouth, the top of the head and parts of the shells of six turtles collected from Ross River in Queensland, Australia.The research team, based at the University of New England and James Cook University, then used a technique called high-throughput sequencingto identify which micro-organisms were present on the turtles, using DNA sequencing to determine which bacteria are present, and their abundance.Previous research has shown that animals in captivity often have less diverse microbiomes, which could affect their long-term health. Dr Donald McKnight, who led the research, said: "Successful conservation efforts inherently require a thorough understanding of an organism's ecology, and we are increasingly realising that microbiomes are a really important part of host ecology. So, filling that gap in our knowledge is important, particularly for animals like turtles."Turtles are one of the most imperilled groups of animals. Nearly two-thirds of all turtle species are either threatened or endangered, and efforts to conserve them often involve breeding turtles in captivity or collecting eggs from wild turtles and raising them in captivity until they are large enough to be released. Studies on other animals have, however, shown that captivity can alter the microbiome."The results showed that the microbiome of the turtles' shells varied, depending on whether algae was present. "It is really interesting that even something like the presence of algae can affect the microbiome" said Dr McKnight. "The algae on turtle's shells is fascinating. It's actually a unique genus that grows almost exclusively on turtles."The algae seen on turtles' shells has many important roles, including providing camouflage and acting as a home for small crustaceans and dispersing seeds. "Our study adds to those roles by showing that algae also affects the microbiome. The mechanism through which it affects the microbiome isn't clear yet, but there are several possibilities. For example, it might compete with some bacteria in order to access the turtles' shells. It may also provide a habitat for bacteria that don't grow well on just the shell itself. Another possibility is that it could retain moisture while turtles bask, and that could affect which species of bacteria grow well. Our study is just an early step in understanding turtle microbiomes, but hopefully future work will build on it and test some of these possibilities." said Dr McKnight.It is important to understand what the microbiome looks like on all parts of the turtle, according to Dr McKnight. He said, "Studies on other animals, including humans, have often found that different parts of the body have different microbiomes. So, it makes sense that this would be true for turtles as well, but it is still really important to test these things rather making assumptions"We don't really know how this affects the success of efforts to conserve turtles by raising them in captivity and releasing them, but it could be an important part of the puzzle. Our study contributes to this by documenting the microbiomes of wild turtles, so that we have a baseline to compare to. More studies are needed to look at whether captivity affects microbiomes in turtles and how those shifts affect conservation."Dr McKnight hopes to continue to research turtle microbiomes: "We are in the early stages of looking at how various environmental and demographic factors affect turtle microbiomes. For example, we want to see if they shift seasonally, if diet affects them, and if different ages and sexes have different microbiomes."
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Animals
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March 26, 2020
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https://www.sciencedaily.com/releases/2020/03/200326144413.htm
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Researchers document seasonal migration in deep-sea
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We've all seen the documentaries that feature scenes of mass migrations on land. Those videos are pretty impressive showing all sorts of animals -- birds, mammals and other creatures -- on the move. What wasn't known was to what extent this was taking place in the deepest parts of our oceans.
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That was until now.Scientists have, for the first time, documented seasonal migrations of fish across the seafloor in deep-sea fish, revealing an important insight that will further scientific understanding of the nature of our planet."We are extremely excited about our findings, which demonstrate a previously unobserved level of dynamism in fishes living on the deep sea floor, potentially mirroring the great migrations which are so well characterised in animal systems on land," said Rosanna Milligan, Assistant Professor at Nova Southeastern University, who started the work at the University of Glasgow.The study -- published today in the The deep sea -- greater than 200-meters water depth -- covers most of the world's surface. Recent advances in technology and computational power have hugely improved our ability to access and study deep sea ecosystems, but there are still many basic questions that we simply don't have answers to.This study now provides evidence of cycles of movement across the seafloor in deep-sea fish, with the study authors believing these movements could be happening in other locations across the world's sea floor too.This work was only possible because of an international collaboration between industry, academia and government, involving more than 10 organisations across Angola, UK and US. It was done using the Deep-ocean Environmental Long-term Observatory System (DELOS).The DELOS observatories are permanently left in place on the seafloor (1,400 m depth) and house separate instrumentation "modules" containing oceanographic sensors, cameras and more. The modules are periodically recovered for data download and servicing using a remotely-operated vehicle (ROV).You can learn more about the DELOS project ONLINE."The work really adds to our understanding of movement patterns in deep-sea fishes and suggests reasons for their behaviours, Milligan said. "Because we were able to link the abundances of fish observed at the seafloor to satellite-derived estimates of primary productivity, our results suggest that even top-level predators and scavengers in the deep oceans could be affected by changes filtering down from the surface of the ocean."Dr. David Bailey, Senior Lecturer in Marine Biology at the University of Glasgow's Institute of Biodiversity, Animal Health and Comparative Medicine, said: "Animal migrations are really important in nature, because when animals move from place to place, they transport energy, carbon and nutrients. We were only able to discover this behaviour because of the collective expertise and decade-long commitment of the Universities and industry partners. These kinds of long-term projects and the datasets they generate are vital to understanding ongoing change in the oceans and how they may be impacted in the future."
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March 26, 2020
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https://www.sciencedaily.com/releases/2020/03/200326144342.htm
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Missing link in coronavirus jump from bats to humans could be pangolins, not snakes
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As scientists scramble to learn more about the SARS-CoV-2 coronavirus, two recent studies of the virus' genome reached controversial conclusions: namely, that snakes are intermediate hosts of the new virus, and that a key coronavirus protein shares "uncanny similarities" with an HIV-1 protein. Now, a study in ACS'
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Understanding where SARS-CoV-2 -- the virus that caused the COVID-19 pandemic -- came from and how it spreads is important for its control and treatment. Most experts agree that bats are a natural reservoir of SARS-CoV-2, but an intermediate host was needed for it to jump from bats to humans.A recent study that analyzed the new virus' genome suggested snakes as this host, despite the fact that coronaviruses are only known to infect mammals and birds. Meanwhile, an unrelated study compared the sequence of the spike protein -- a key protein responsible for getting the virus into mammalian cells -- of the new coronavirus to that of HIV-1, noting unexpected similarities. Although the authors withdrew this preprint manuscript after scientific criticism, it spawned rumors and conspiracy theories that the new coronavirus could have been engineered in a lab. Yang Zhang and colleagues wanted to conduct a more careful and complete analysis of SARS-CoV-2 sequences to resolve these issues.Compared to the previous studies, the researchers used larger data sets and newer, more accurate bioinformatics methods and databases to analyze the SARS-CoV-2 genome. They found that, in contrast to the claim that four regions of the spike protein were uniquely shared between SARS-CoV-2 and HIV-1, the four sequence segments could be found in other viruses, including bat coronavirus.After uncovering an error in the analysis that suggested snakes as an intermediate host, the team searched DNA and protein sequences isolated from pangolin tissues for ones similar to SARS-CoV-2. The researchers identified protein sequences in sick animals' lungs that were 91% identical to the human virus' proteins. Moreover, the receptor binding domain of the spike protein from the pangolin coronavirus had only five amino acid differences from SARS-CoV-2, compared with 19 differences between the human and bat viral proteins. This evidence points to the pangolin as the most likely intermediate host for the new coronavirus, but additional intermediate hosts could be possible, the researchers say.The authors acknowledge funding from the National Science Foundation, the National Institute of General Medical Sciences, the National Institute of Allergy and Infectious Diseases and the Extreme Science and Engineering Discovery Environment.
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Animals
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March 26, 2020
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https://www.sciencedaily.com/releases/2020/03/200326124127.htm
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New feathered dinosaur was one of the last surviving raptors
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A new feathered dinosaur that lived in New Mexico 67 million years ago is one of the last known surviving raptor species, according to a new publication in the journal
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Dineobellator notohesperus adds to scientists' understanding of the paleo-biodiversity of the American Southwest, offering a clearer picture of what life was like in this region near the end of the reign of the dinosaurs.Steven Jasinski, who recently completed his Ph.D. in Penn's Department of Earth and Environmental Sciences in the School of Arts and Sciences, led the work to describe the new species, collaborating with doctoral advisor Peter Dodson of the School of Veterinary Medicine and Penn Arts and Sciences and as well as Robert Sullivan of the New Mexico Museum of Natural History and Science in Albuquerque.In 2008, Sullivan found fossils of the new species in Cretaceous rocks of the San Juan Basin, New Mexico. He, along with his field team of Jasinski and James Nikas, collected the specimen on U.S. federal land under a permit issued by the Bureau of Land Management. The entire specimen was recovered over four field seasons. Jasinski and his coauthors gave the species its official name, Dineobellator notohesperus, which means "Navajo warrior from the Southwest," in honor of the people who today live in the same region where this dinosaur once dwelled.Dineobellator, as well as its Asian cousin Velociraptor, belong to a group of dinosaurs known as the dromaeosaurids. Members of this group are commonly referred to as "raptor" dinosaurs, thanks to movies such as "Jurassic Park" and "Jurassic World." But unlike the terrifying beasts depicted in film, Dineobellator stood only about 3.5 feet (about 1 meter) at the hip and was 6 to 7 feet (about 2 meters) long -- much smaller than its Hollywood counterparts.Raptor dinosaurs are generally small, lightly built predators. Consequently, their remains are rare, particularly from the southwestern United States and Mexico. "While dromaeosaurids are better known from places like the northern United States, Canada, and Asia, little is known of the group farther south in North America," says Jasinski.While not all of the bones of this dinosaur were recovered, bones from the forearm have quill nobs -- small bumps on the surface where feathers would be anchored by ligaments -- an indication that Dineobellator bore feathers in life, similar to those inferred for Velociraptor.Features of the animal's forelimbs, including enlarged areas of the claws, suggest this dinosaur could strongly flex its arms and hands. This ability may have been useful for holding on to prey -- using its hands for smaller animals such as birds and lizards, or perhaps its arms and feet for larger species such as other dinosaurs.Its tail also possessed unique characteristics. While most raptors' tails were straight and stiffened with rod-like structures, Dineobellator's tail was rather flexible at its base, allowing the rest of the tail to remain stiff and act like a rudder."Think of what happens with a cat's tail as it is running," says Jasinski. "While the tail itself remains straight, it is also whipping around constantly as the animal is changing direction. A stiff tail that is highly mobile at its base allows for increased agility and changes in direction, and potentially aided Dineobellator in pursuing prey, especially in more open habitats."This new dinosaur provides a clearer picture of the biology of North American dromaeosaurid dinosaurs, especially concerning the distribution of feathers among its members."As we find evidence of more members possessing feathers, we believe it is likely that all the dromaeosaurids had feathers," says Jasinski. The discovery also hints at some of the predatory habits of a group of iconic meat-eating dinosaurs that lived just before the extinction event that killed off all the dinosaurs that weren't birds.Jasinski plans to continue his field research in New Mexico with the hope of finding more fossils."It was with a lot of searching and a bit of luck that this dinosaur was found weathering out of a small hillside," he says. "We do so much hiking and it is easy to overlook something or simply walk on the wrong side of a hill and miss something. We hope that the more we search, the better chance we have of finding more of Dineobellator or the other dinosaurs it lived alongside."
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Animals
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March 25, 2020
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https://www.sciencedaily.com/releases/2020/03/200325154100.htm
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A small forage fish should command greater notice, researchers say
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A slender little fish called the sand lance plays a big role as "a quintessential forage fish" for puffins, terns and other seabirds, humpback whales and other marine mammals, and even bigger fish such as Atlantic sturgeon, cod and bluefin tuna in the Gulf of Maine and northwest Atlantic Ocean. But scientists say right now they know far too little about its biology and populations to inform "relevant management, climate adaptation and conservation efforts."
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A collaborative team of 24 coauthors led by first author and marine ecologist Michelle Staudinger at the University of Massachusetts Amherst's Northeast Climate Adaptation Science Center this week is calling for increased focus on sand lance and their ecological role in the region's "dynamic ecosystem," which is facing increased pressure and risks from climate change, fishing and offshore wind energy development. Details are in the current issue of Two species, American and Northern sand lance, are so streamlined that they can dive at swimming speed into the sandy sea floor, burrowing to escape predators. Staudinger explains, "They're unique among forage fish because of their elongate body shape and hiding behaviors. Their shape makes them very attractive to many predators because they're easy to swallow. Most marine predators don't chew their food, rather they swallow their food whole. It's like eating spaghetti instead of a meatball; there are no legs or spines to get caught in your mouth or throat. Even small seabird chicks can swallow large sand lance because they slide right down into the gullet."Holly Goyert, a UMass post-doctoral researcher with the project who is now working under contract to the NOAA National Ocean Service adds that even though sand lance occur in huge schools, "their slender bodies make them very difficult to catch in marine survey nets so we have very little information on their abundance and distribution. We just can't catch them reliably and efficiently enough to understand how big their populations are. We have some information on their early life and adult stages, but there are significant gaps, especially in the juvenile stages and first few years of their lives."Staudinger and Justin Suca, a Ph.D. student at MIT-Woods Hole Oceanographic Institution Joint Program who contributed to the study, point out that sand lance are an unmanaged forage fish in the region, so scientists don't collect regular data on them.Staudinger's team says its report represents the first comprehensive assessment of this important forage fish in the Northwest Atlantic, though similar efforts have been carried out in the Pacific Northwest and Europe. In the Atlantic, sand lance are observed to be a significant food source for the federally endangered Roseate tern, Atlantic sturgeon and cod, Harbor and Grey seals and Minke and Humpback whales. "This paper is a call to our peers and colleagues that there is a big gap in knowledge, and to bring more attention to these species as unmanaged forage fish," says Staudinger.To begin to address this need, she, Linda Welch of the U.S. Fish and Wildlife Service, and Dave Wiley of the Stellwagen Bank National Marine Sanctuary led their colleagues from 15 state and federal agencies, academic institutions and nonprofits in a 2017 workshop. The goal was to synthesize available data on the life history, behavior, distribution, feeding ecology, threats and vulnerabilities and ecosystem services role of sand lance in the northwest Atlantic. Wiley says "Sand lance are a key ingredient in the sanctuary's productivity. The more we know and understand about this forage fish the better equipped we will be to conserve and protect marine species that depend on this critical food source."In addition to UMass Amherst's Northeast Climate Adaptation Science Center, the work was supported by Woods Hole Oceanographic Institution, the U.S. Fish and Wildlife Service, NOAA/Stellwagen Bank National Marine Sanctuary, Boston University and others.Overall, they report that 72 regional predators including 45 fish species, two squids, 16 seabirds, and nine marine mammals were found to consume sand lance. Staudinger adds that because sand lance are winter spawners, they are particularly vulnerable to warming ocean temperatures in Gulf of Maine waters, which are known as a global "hotspot of warming." The eel-like fish may also be less adaptable than other fish species -- they are very dependent on sandy bottom marine environments increasingly targeted by dredging for beach nourishment and siting of wind energy turbines.The researchers say, "Priority research needs identified during this effort include basic information on the patterns and drivers in abundance and distribution of Ammodytes (sand lance), improved assessments of reproductive biology schedules, and investigations of regional sensitivity and resilience to climate change, fishing and habitat disturbance. Food-web studies are also needed to evaluate trophic linkages, and to assess the consequences of inconsistent zooplankton prey and predator fields on energy flow within the northwest Atlantic ecosystem."
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Animals
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March 25, 2020
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https://www.sciencedaily.com/releases/2020/03/200325154056.htm
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Bats depend on conspecifics when hunting above farmland
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Common noctules -- one of the largest bat species native to Germany -- are searching for their fellows during their hunt for insects above farmland. Scientists from the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW) show in a paper published in the journal
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Human activities have massively changed the face of the earth over the past centuries. While Central Europe was covered by dense primeval forests in ancient times, today farmland, meadows and managed forests dominate the countryside. Humans have transformed natural landscapes into cultural landscapes and many wild animals disappeared, while others found new ecological niches. Bats were particularly successful in the latter process. As so-called cultural successors, many species were able to survive in modern environments, finding shelter in buildings and feeding above arable land and managed forests. But what is the secret of their success? Are they particularly efficient hunters?To verify this, a research team from Leibniz-IZW equipped two groups of the Common noctule with sensors that recorded the both spatial position and echolocations calls at the place of the tagged bat. From acoustic recordings of special hunting calls, so-called "feeding buzzes," the authors deduced when and where the bats preyed on insects. In addition, the recording of the acoustic environment made it possible to determine whether conspecifics were present. Individuals of the first population hunted for insects in an area north of Berlin, which is characterized by large wheat, rape and corn fields. Individuals of the second population went in search of food southeast of Berlin over an area dominated by pine forest. In both areas, bats showed two flight patterns -- commuting flight and the small-scale search flight, in which the animals zigzagged around in above a small area. When hunting over the forest, the bats regularly emitted feeding buzzes, both during commuting flight and during small-scale search flight, regardless of whether other bats were around. Apparently, they were successful as individual hunters. Above farmland, however, commuting bats did not emit feeding buzzes. Only after encountering a conspecific, they switched to the small-scale search flight, which was accompanied by many hunting calls.The conclusion of the scientists: Above farmland, prey is presumably rare and only found in larger numbers at a few places -- for example, on hedges or ditches. This is why bats eavesdropped on their conspecifics when foraging above farmland. When they recognized a successful hunt by the feeding calls of their neighbor, they joined the group of hunting conspecifics and switched to small-scale search flights in order to effectively feed on the swarm of insects they had tracked down. Over forests, on the other hand, there is likely to be more prey, which may also be more evenly distributed. Here the animals were successful even without eavesdropping on conspecifics."Community hunting makes it possible for the bats to find food even above farmland with low prey density," says Christian Voigt, head of the Department of Evolutionary Ecology at Leibniz-IZW. "However, this only works if the population is sufficiently large. Due to insect mortality and collisions with wind turbines, the populations of the Common noctule and other species could decline further. These populations could fall below the critical population density, so that joint hunting may no longer be possible. Local populations that are dependent on this form of food acquisition would then be on the brink of extinction."
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Animals
| 2,020 |
May 6, 2021
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https://www.sciencedaily.com/releases/2021/05/210506142133.htm
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Most human origins stories are not compatible with known fossils
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In the 150 years since Charles Darwin speculated that humans originated in Africa, the number of species in the human family tree has exploded, but so has the level of dispute concerning early human evolution. Fossil apes are often at the center of the debate, with some scientists dismissing their importance to the origins of the human lineage (the "hominins"), and others conferring them starring evolutionary roles. A new review out on May 7 in the journal
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Humans diverged from apes -- specifically, the chimpanzee lineage -- at some point between about 9.3 million and 6.5 million years ago, towards the end of the Miocene epoch. To understand hominin origins, paleoanthropologists aim to reconstruct the physical characteristics, behavior, and environment of the last common ancestor of humans and chimps."When you look at the narrative for hominin origins, it's just a big mess -- there's no consensus whatsoever," said Sergio Almécija, a senior research scientist in the American Museum of Natural History's Division of Anthropology and the lead author of the review. "People are working under completely different paradigms, and that's something that I don't see happening in other fields of science."There are two major approaches to resolving the human origins problem: "Top-down," which relies on analysis of living apes, especially chimpanzees; and "bottom-up," which puts importance on the larger tree of mostly extinct apes. For example, some scientists assume that hominins originated from a chimp-like knuckle-walking ancestor. Others argue that the human lineage originated from an ancestor more closely resembling, in some features, some of the strange Miocene apes.In reviewing the studies surrounding these diverging approaches, Almécija and colleagues with expertise ranging from paleontology to functional morphology and phylogenetics discuss the limitations of relying exclusively on one of these opposing approaches to the hominin origins problem. "Top-down" studies sometimes ignore the reality that living apes (humans, chimpanzees, gorillas, orangutans, and hylobatids) are just the survivors of a much larger, and now mostly extinct, group. On the other hand, studies based on the "bottom-up"approach are prone to giving individual fossil apes an important evolutionary role that fits a preexisting narrative."In The Descent of Man in 1871, Darwin speculated that humans originated in Africa from an ancestor different from any living species. However, he remained cautious given the scarcity of fossils at the time," Almécija said. "One hundred fifty years later, possible hominins -- approaching the time of the human-chimpanzee divergence -- have been found in eastern and central Africa, and some claim even in Europe. In addition, more than 50 fossil ape genera are now documented across Africa and Eurasia. However, many of these fossils show mosaic combinations of features that do not match expectations for ancient representatives of the modern ape and human lineages. As a consequence, there is no scientific consensus on the evolutionary role played by these fossil apes."Overall, the researchers found that most stories of human origins are not compatible with the fossils that we have today."Living ape species are specialized species, relicts of a much larger group of now extinct apes. When we consider all evidence -- that is, both living and fossil apes and hominins -- it is clear that a human evolutionary story based on the few ape species currently alive is missing much of the bigger picture," said study co-author Ashley Hammond, an assistant curator in the Museum's Division of Anthropology.Kelsey Pugh, a Museum postdoctoral fellow and study co-author adds, "The unique and sometimes unexpected features and combinations of features observed among fossil apes, which often differ from those of living apes, are necessary to untangle which features hominins inherited from our ape ancestors and which are unique to our lineage."Living apes alone, the authors conclude, offer insufficient evidence. "Current disparate theories regarding ape and human evolution would be much more informed if, together with early hominins and living apes, Miocene apes were also included in the equation," says Almécija. "In other words, fossil apes are essential to reconstruct the 'starting point' from which humans and chimpanzees evolved."
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Biology
| 2,021 |
May 6, 2021
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https://www.sciencedaily.com/releases/2021/05/210506142039.htm
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The cerebellum may have played an important role in the evolution of the human brain
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The cerebellum -- a part of the brain once recognized mainly for its role in coordinating movement -- underwent evolutionary changes that may have contributed to human culture, language and tool use. This new finding appears in a study by Elaine Guevara of Duke University and colleagues, published May 6th in the journal
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Scientists studying how humans evolved their remarkable capacity to think and learn have frequently focused on the prefrontal cortex, a part of the brain vital for executive functions, like moral reasoning and decision making. But recently, the cerebellum has begun receiving more attention for its role in human cognition. Guevara and her team investigated the evolution of the cerebellum and the prefrontal cortex by looking for molecular differences between humans, chimpanzees, and rhesus macaque monkeys. Specifically, they examined genomes from the two types of brain tissue in the three species to find epigenetic differences. These are modifications that do not change the DNA sequence but can affect which genes are turned on and off and can be inherited by future generations.Compared to chimpanzees and rhesus macaques, humans showed greater epigenetic differences in the cerebellum than the prefrontal cortex, highlighting the importance of the cerebellum in human brain evolution. The epigenetic differences were especially apparent on genes involved in brain development, brain inflammation, fat metabolism and synaptic plasticity -- the strengthening or weakening of connections between neurons depending on how often they are used.The epigenetic differences identified in the new study are relevant for understanding how the human brain functions and its ability to adapt and make new connections. These epigenetic differences may also be involved in aging and disease. Previous studies have shown that epigenetic differences between humans and chimpanzees in the prefrontal cortex are associated with genes involved in psychiatric conditions and neurodegeneration. Overall, the new study affirms the importance of including the cerebellum when studying how the human brain evolved.Guevara adds, "Our results support an important role for the cerebellum in human brain evolution and suggest that previously identified epigenetic features distinguishing the human neocortex are not unique to the neocortex."
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Biology
| 2,021 |
May 6, 2021
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https://www.sciencedaily.com/releases/2021/05/210506125820.htm
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Researchers speed identification of DNA regions that regulate gene expression
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St. Jude Children's Research Hospital scientists have developed an integrated, high-throughput system to better understand and possibly manipulate gene expression for treatment of disorders such as sickle cell disease and beta thalassemia. The research appears today in the journal
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Researchers used the system to identify dozens of DNA regulatory elements that act together to orchestrate the switch from fetal to adult hemoglobin expression. The method can also be used to study other diseases that involve gene regulation.Regulatory elements, also called genetic switches, are scattered throughout non-coding regions of DNA. These regions do not encode genes and make up about 98% of the genome. The elements have a variety of names -- enhancer, repressor, insulator and more -- but the specific genes they regulate, how the regulatory elements act together, and answers to other questions have been unclear."Without the high-throughput system, identifying key regulatory elements is often extremely slow," said corresponding author Yong Cheng, Ph.D., of the St. Jude Departments of Hematology and Computational Biology. Mitchell Weiss, M.D., Ph.D., Hematology chair, is co-corresponding author."For example, despite decades of research, fewer than half of regulatory elements and the associated genetic variants that account for fetal hemoglobin levels have been identified," Cheng said.Precision editing provides key details about regulation of gene expressionThe new system combines bioinformatic prediction algorithms and an adenine base editing tool with tests to measure how base gene editing affects gene expression. Base editing works more precisely than conventional gene-editing tools such as CRISPR/Cas9, by changing a single letter in the four-letter DNA alphabet at high efficiency without creating larger insertions or deletions.Researchers used the base editor ABEmax to make 10,156 specific edits in 307 regulatory elements that were predicted to affect fetal hemoglobin expression. The expression can modify the severity of hemoglobin disorders such as sickle cell disease. The edits changed the DNA bases adenine and thymine to guanine and cytosine. The study focused on regulatory elements in the genes BCL11A, MYB-HBS1L, KLF1 and beta-like globin genes.Using this approach, the scientists validated the few known regulatory elements of fetal hemoglobin expression and identified many new ones.
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Biology
| 2,021 |
May 6, 2021
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https://www.sciencedaily.com/releases/2021/05/210506125743.htm
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Blocking viruses' exit strategy
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The Marburg virus, a relative of the Ebola virus, causes a serious, often-fatal hemorrhagic fever. Transmitted by the African fruit bat and by direct human-to-human contact, Marburg virus disease currently has no approved vaccine or antivirals to prevent or treat it.
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A team of researchers is working to change that. In a new paper in the journal In addition, due to possible similarities in virus-host interactions between Marburg and SARS-CoV-2, the team has conducted experiments on the culprit behind the coronavirus pandemic. While preliminary and thus-far-unpublished, their initial tests show signs of promise."It really is exciting," says Ronald Harty, a co-corresponding author of the research and a professor at Penn Vet. "These viruses are quite different but may be interacting with the same host proteins to control efficient egress and spread, so our inhibitors may be able to block them both."While many antivirals target the virus itself, the drug candidates that Harty and colleagues have been developing for years are known as "host-oriented." They prevent virus-host interactions by blocking the proteins in host cells that viruses hijack during late stages of infection.Not only does this approach help avoid the likelihood that a virus would evolve to resist such a therapy, but it also increases the chance that a drug could be used against multiple viruses, as many rely on the same host cell machinery to reproduce and spread.The Marburg and Ebola viruses use the VP40 protein to interact with a host protein called Nedd4 to complete the process of "budding" off a host cell. This stage of infection, which is key to viral spread, is the one the research team has targeted.In previous studies, they had tested a variety of small molecule inhibitors of this process using laboratory tests that relied on non-infectious and more-benign viral models. Those assays helped them land on a leading candidate, FC-10696, for further study.In the current work, they zeroed in on this candidate with rigorous evaluations. First, they tested the inhibitor to ensure it would be safe and retained long enough in the body to have an effect. Next, because the live Marburg virus is too dangerous to study safely in anything but a Biosafety Level 4 (BSL-4) laboratory, they used an assay to look at what are known as virus-like particles, or VLPs, which can bud off of a host cell like the live virus but are not infectious.Using the Biosafety Level 2 laboratory at Penn, "it's a very quick way we can test these inhibitors," Harty says.After seeing a dose-dependent response to FC-10696 on VLP budding in cells in a cell-culture dish, the researchers tested the compound using the real Marburg virus. These studies were done in a BSL-4 lab at Texas Biomedical Research Institute and found the compound inhibited the budding and spread of live Marburg virus in two human cell types, including in macrophages, an immune cell type commonly infected by the virus.Finally, they evaluated the compound in mice that had been exposed to Marburg virus. Those mice treated with FC-10696 took longer to display disease symptoms and had a reduced viral load."These are the first promising in vivo data for our compounds," Harty says. "Whereas the control group all became sick very quickly and died, with the treated animals there was one survivor and others showed delayed onset of clinical symptoms. It's showing that our inhibitors are having an effect."A portion of the VP40 protein in Marburg and Ebola viruses that enables budding is known as a PPxY motif. SARS-CoV-2 also happens to have this motif on its Spike (S) protein, which it uses to infect human cells. In a follow-up experiment that is not yet published, the researchers found evidence that FC-10696 was able to inhibit budding of the SARS-CoV-2 coronavirus in human lung epithelial cells."The SARS-CoV-2 studies are ongoing, and they're very exciting," Harty says.Ronald N. Harty is a professor of pathobiology and microbiology in the University of Pennsylvania School of Veterinary Medicine.Harty's coauthors were Ziying Han, Jingjing Liang, Ariel Shepley-McTaggart, and Bruce D. Freedman of Penn Vet; Hong Ye, Jay E. Wrobel, and Allen B. Reitz of the Fox Chase Chemical Diversity Center; Michael S. Saporito of Intervi, LLC; and Alison Whigham, Katrina Kavelish, and Olena Shtanko of the Texas Biomedical Research Institute. Han was first author and Harty and Shtanko were co-corresponding authors. Harty and Freedman are co-founders of Intervi, LLC.The study was supported in part by the National Institutes of Health (grants AI138052, AI138630, AI129890, and AI070077) and an Innovator Award from The Wellcome Trust.
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Biology
| 2,021 |
May 6, 2021
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https://www.sciencedaily.com/releases/2021/05/210506105355.htm
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Alzheimer's study: A Mediterranean diet might protect against memory loss and dementia
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In Alzheimer's disease, neurons in the brain die. Largely responsible for the death of neurons are certain protein deposits in the brains of affected individuals: So-called beta-amyloid proteins, which form clumps (plaques) between neurons, and tau proteins, which stick together the inside of neurons. The causes of these deposits are as yet unclear. In addition, a rapidly progressive atrophy, i.e. a shrinking of the brain volume, can be observed in affected persons. Alzheimer's symptoms such as memory loss, disorientation, agitation and challenging behavior are the consequences.
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Scientists at the DZNE led by Prof. Michael Wagner, head of a research group at the DZNE and senior psychologist at the memory clinic of the University Hospital Bonn, have now found in a study that a regular Mediterranean-like dietary pattern with relatively more intake of vegetables, legumes, fruit, cereals, fish and monounsaturated fatty acids, such as from olive oil, may protect against protein deposits in the brain and brain atrophy. This diet has a low intake of dairy products, red meat and saturated fatty acids.A total of 512 subjects with an average age of around seventy years took part in the study. 169 of them were cognitively healthy, while 343 were identified as having a higher risk of developing Alzheimer's disease -- due to subjective memory impairment, mild cognitive impairment that is the precursor to dementia, or first-degree relationship with patients diagnosed with Alzheimer's disease. The nutrition study was funded by the Diet-Body-Brain competence cluster of the German Federal Ministry of Education and Research (BMBF) and took place as part of the so-called DELCODE study of the DZNE, which does nationwide research on the early phase of Alzheimer's disease -- that period before pronounced symptoms appear."People in the second half of life have constant eating habits. We analyzed whether the study participants regularly eat a Mediterranean diet -- and whether this might have an impact on brain health ," said Prof. Michael Wagner. The participants first filled out a questionnaire in which they indicated which portions of 148 different foods they had eaten in the past months. Those who frequently ate healthy foods typical of the Mediterranean diet, such as fish, vegetables and fruit, and only occasionally consumed foods such as red meat, scored highly on a scale.The scientists then investigated brain atrophy: they performed brain scans with magnetic resonance imaging (MRI) scanners to determine brain volume. In addition, all subjects underwent various neuropsychological tests in which cognitive abilities such as memory functions were examined. The research team also looked at biomarker levels (measured values) for amyloid beta proteins and tau proteins in the so-called cerebrospinal fluid (CSF) of 226 subjects.The researchers, led by Michael Wagner, found that those who ate an unhealthy diet had more pathological levels of these biomarkers in the cerebrospinal fluid than those who regularly ate a Mediterranean-like diet. In the memory tests, the participants who did not adhere to the Mediterranean diet also performed worse than those who regularly ate fish and vegetables. "There was also a significant positive correlation between a closer adherence to a Mediterranean-like diet and a higher volume of the hippocampus. The hippocampus is an area of the brain that is considered the control center of memory. It shrinks early and severely in Alzheimer's disease," explained Tommaso Ballarini, PhD, postdoctoral fellow in Michael Wagner's research group and lead author of the study."It is possible that the Mediterranean diet protects the brain from protein deposits and brain atrophy that can cause memory loss and dementia. Our study hints at this," Ballarini said. "But the biological mechanism underlying this will have to be clarified in future studies." As a next step, Ballarini and Wagner now plan to re-examine the same study participants in four to five years to explore how their nutrition -- Mediterranean-like or unhealthy -- affects brain aging over time.
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Biology
| 2,021 |
May 6, 2021
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https://www.sciencedaily.com/releases/2021/05/210505111334.htm
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How mitochondria make the cut
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Mitochondria either split in half to multiply within the cell, or cut off their ends to get rid of damaged material. That's the take-away message from EPFL biophysicists in their latest research investigating mitochondrial fission. It's a major departure from the classical textbook explanation of the life cycle of this well-known organelle, the powerhouse of the cell. The results are published today in
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"Until this study, it was poorly understood how mitochondria decide where and when to divide," says EPFL biophysicist Suliana Manley and senior author of the study.Mitochondrial fission is important for the proliferation of mitochondria, which is fundamental for cellular growth. As a cell gets bigger, and eventually divides, it needs more fuel and therefore more mitochondria. But mitochondria have their own DNA that is separate from the cell's DNA, so mitochondria have their own life cycle. They can only proliferate by replicating their DNA, and dividing themselves.The textbook explanation of mitochondrial fission details the protein machinery that cuts the mitochondrion into two daughter mitochondria, leading to proliferation. But there was mounting evidence in the scientific literature that mitochondrial fission was also a way of getting rid of damaged material."For me, the big question was how do mitochondria know when to proliferate or when to degrade? How does the cell regulate these two opposing functions of mitochondrial fission?" explains EPFL postdoc Tatjana Kleele and first author of the study.Four years of research and 2000 mitochondria later, Kleele and Manley found that the splitting location of mitochondria is not at all random.Until now, the dynamics of mitochondrial fission sites had never been measured with high precision and in large numbers. But thanks to their own super resolution microscope (iSIM), the EPFL biophysicists were able to observe many individual mitochondria, in living cancer cell lines and mouse cardiomyocytes, as they split into smaller segments."The size of a mitochondrion is just around the diffraction limit for light microscopy, making it impossible to study mitochondrial physiology and shape changes at the sub-organelle level. Using a custom built super-resolution microscope, which allows fast imaging with a two-fold increase in resolution, we were able to analyse a large number of mitochondrial divisions," explains Manley.From these observations, they could both quantify the position of fission with high precision, and also detect signs of dysfunction in small parts of the organelle with the help of fluorescent biosensors. A low pH within a mitochondrion is a sign that the proton pump necessary for making ATP, energy for the cell, is no longer working optimally. Calcium concentrations provided information about the mitochondria structures.They observed two types of mitochondrial division: midzone and peripheral. They discovered that midzone division of mitochondria has all of the textbook molecular machinery of fission. In contrast, peripheral division is associated with mitochondrial stress and dysfunction, and the smaller daughter mitochondrion is subsequently degraded.Next, the biophysicists wanted to know if they could observe the same behavior in heart cells from mice. In collaboration with the laboratory of Thierry Pedrazzini (CHUV), they discovered that mouse heart muscle cells (cardiomyocytes) can independently regulate those two types of fissions, because they use different proteins and machineries.When the scientists stimulated the cardiomyocytes to strongly contract with pharmaceuticals, they found that peripheral division rates increase. In other words, when the cardiomyocytes were over-stimulated or stressed, the mitochondria produced tremendous amounts of energy in order for the heart cells to beat quickly. A by-product of this energy production are free radicals, aka reactive oxygen species, known to lead to dysfunction within the cell, including dysfunction of the mitochondria. The peripheral divisions therefore increase to get rid of damaged mitochondria due to the stress.When the scientists stimulated the cardiomyocytes to proliferate, they indeed noticed more midzone divisions."The behavior of mitochondrial fission that we've observed in the lab is very likely relevant for all mammalian cells," says Kleele.For Manley, this regulation of mitochondrial fission is important human diseases, such as neurodegeneration and cardiovascular dysfunction, which are both associated with overactive mitochondrial fission. "Therapeutic approaches are rare, since globally targeting mitochondrial fission has many side effects. By identifying proteins which are specifically involved in either biogenesis or degradation, we can now provide more precise targets for pharmacological approaches," concludes Manley.
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Biology
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May 5, 2021
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https://www.sciencedaily.com/releases/2021/05/210505130544.htm
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New ant species named in recognition of gender diversity
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A newly discovered miniature trap jaw ant from the evergreen tropical forests of Ecuador bears the curious Latin name
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The insect was first found by Philipp Hoenle of the Technical University of Darmstadt, Germany, during a cooperative investigation of the Reserva Río Canandé in 2018. The reserve belongs to the NGO Jocotoco, and preserves a small part of the highly threatened biodiversity hotspots called the Chocó.Hoenle reached out to taxonomic expert Douglas Booher of Yale University. Soon, Booher responded with excitement that this species was unlike any other of the 850+ species belonging to its genus. As a result, the team described the previously unknown to science species and its remarkable trap-jaw morphology in a research paper, published in the peer-reviewed, open-access journal Curiously, it was no other but lead singer and lyricist of the American alternative rock band R.E.M. Michael Stipe that joined Booher in the writing of the etymology section for the research article. This is the part in the publication, where they honor their mutual friend, activist and artist Jeremy Ayers and explain the origin of the species name."In contrast to the traditional naming practices that identify individuals as one of two distinct genders, we have chosen a non-Latinized portmanteau honoring the artist Jeremy Ayers and representing people that do not identify with conventional binary gender assignments -- Current nomenclature practice on how to name animal species after people only differentiates between male and female personal names, offering respectively the ending -ae for a woman or -i for a man.The research team additionally propose that the -they suffix can be used for singular honorific names of non-binary identifiers.When asked about the choice of a name for the ant, Booher said: "Such a beautiful and rare animal was just the species to celebrate both biological and human diversity. Small changes in language have had a large impact on culture. Language is dynamic and so should be the change in naming species -- a basic language of science."With their choice, the team invites the scientific community to keep pace with the likes of Oxford English Dictionary, Merriam-Webster Unabridged Dictionary and HSBC Bank, who have also adapted their own institutional practices, language usage and recognition to represent gender diversity."The discovery of such an unusual rare ant highlights the importance of scientific exploration and conservation of the Chocó region in Ecuador, which is at the same time one of the most biodiverse and threatened areas on our planet," the researchers add in conclusion.
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Biology
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May 5, 2021
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https://www.sciencedaily.com/releases/2021/05/210505113731.htm
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Process for eliminating unneeded cells may also protect against cancer
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For all animals, eliminating some cells is a necessary part of embryonic development. Living cells are also naturally sloughed off in mature tissues; for example, the lining of the intestine turns over every few days.
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One way that organisms get rid of unneeded cells is through a process called extrusion, which allows cells to be squeezed out of a layer of tissue without disrupting the layer of cells left behind. MIT biologists have now discovered that this process is triggered when cells are unable to replicate their DNA during cell division.The researchers discovered this mechanism in the worm C. elegans, and they showed that the same process can be driven by mammalian cells; they believe extrusion may serve as a way for the body to eliminate cancerous or precancerous cells."Cell extrusion is a mechanism of cell elimination used by organisms as diverse as sponges, insects, and humans," says H. Robert Horvitz, the David H. Koch Professor of Biology at MIT, a member of the McGovern Institute for Brain Research and the Koch Institute for Integrative Cancer Research, a Howard Hughes Medical Institute investigator, and the senior author of the study. "The discovery that extrusion is driven by a failure in DNA replication was unexpected and offers a new way to think about and possibly intervene in certain diseases, particularly cancer."MIT postdoc Vivek Dwivedi is the lead author of the paper, which appears today in Nature. Other authors of the paper are King's College London research fellow Carlos Pardo-Pastor, MIT research specialist Rita Droste, MIT postdoc Ji Na Kong, MIT graduate student Nolan Tucker, Novartis scientist and former MIT postdoc Daniel Denning, and King's College London professor of biology Jody Rosenblatt.In the 1980s, Horvitz was one of the first scientists to analyze a type of programmed cell suicide called apoptosis, which organisms use to eliminate cells that are no longer needed. He made his discoveries using C. elegans, a tiny nematode that contains exactly 959 cells. The developmental lineage of each cell is known, and embryonic development follows the same pattern every time. Throughout this developmental process, 1,090 cells are generated, and 131 cells undergo programmed cell suicide by apoptosis.Horvitz's lab later showed that if the worms were genetically mutated so that they could not eliminate cells by apoptosis, a few of those 131 cells would instead be eliminated by cell extrusion, which appears to be able to serve as a backup mechanism to apoptosis. How this extrusion process gets triggered, however, remained a mystery.To unravel this mystery, Dwivedi performed a large-scale screen of more than 11,000 C. elegans genes. One by one, he and his colleagues knocked down the expression of each gene in worms that could not perform apoptosis. This screen allowed them to identify genes that are critical for turning on cell extrusion during development.To the researchers' surprise, many of the genes that turned up as necessary for extrusion were involved in the cell division cycle. These genes were primarily active during first steps of the cell cycle, which involve initiating the cell division cycle and copying the cell's DNA.Further experiments revealed that cells that are eventually extruded do initially enter the cell cycle and begin to replicate their DNA. However, they appear to get stuck in this phase, leading them to be extruded.Most of the cells that end up getting extruded are unusually small, and are produced from an unequal cell division that results in one large daughter cell and one much smaller one. The researchers showed that if they interfered with the genes that control this process, so that the two daughter cells were closer to the same size, the cells that normally would have been extruded were able to successfully complete the cell cycle and were not extruded.The researchers also showed that the failure of the very small cells to complete the cell cycle stems from a shortage of the proteins and DNA building blocks needed to copy DNA. Among other key proteins, the cells likely don't have enough of an enzyme called LRR-1, which is critical for DNA replication. When DNA replication stalls, proteins that are responsible for detecting replication stress quickly halt cell division by inactivating a protein called CDK1. CDK1 also controls cell adhesion, so the researchers hypothesize that when CDK1 is turned off, cells lose their stickiness and detach, leading to extrusion.Horvitz's lab then teamed up with researchers at King's College London, led by Rosenblatt, to investigate whether the same mechanism might be used by mammalian cells. In mammals, cell extrusion plays an important role in replacing the lining of the intestines, lungs, and other organs.The researchers used a chemical called hydroxyurea to induce DNA replication stress in canine kidney cells grown in cell culture. The treatment quadrupled the rate of extrusion, and the researchers found that the extruded cells made it into the phase of the cell cycle where DNA is replicated before being extruded. They also showed that in mammalian cells, the well-known cancer suppressor p53 is involved in initiating extrusion of cells experiencing replication stress.That suggests that in addition to its other cancer-protective roles, p53 may help to eliminate cancerous or precancerous cells by forcing them to extrude, Dwivedi says."Replication stress is one of the characteristic features of cells that are precancerous or cancerous. And what this finding suggests is that the extrusion of cells that are experiencing replication stress is potentially a tumor suppressor mechanism," he says.The fact that cell extrusion is seen in so many animals, from sponges to mammals, led the researchers to hypothesize that it may have evolved as a very early form of cell elimination that was later supplanted by programmed cell suicide involving apoptosis."This cell elimination mechanism depends only on the cell cycle," Dwivedi says. "It doesn't require any specialized machinery like that needed for apoptosis to eliminate these cells, so what we've proposed is that this could be a primordial form of cell elimination. This means it may have been one of the first ways of cell elimination to come into existence, because it depends on the same process that an organism uses to generate many more cells."Dwivedi, who earned his PhD at MIT, was a Khorana scholar before entering MIT for graduate school.This research was supported by the Howard Hughes Medical Institute and the National Institutes of Health.
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Biology
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May 5, 2021
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https://www.sciencedaily.com/releases/2021/05/210505113702.htm
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Fast changing smells can teach mice about space
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Researchers at the Francis Crick Institute and UCL (University College London) have found that mice can sense extremely fast and subtle changes in the structure of odours and use this to guide their behaviour. The findings, published in
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Odour plumes, like the steam off a hot cup of coffee, are complex and often turbulent structures, and can convey meaningful information about an animal's surroundings, like the movements of a predator or the location of food sources. But it has previously been assumed that mammalian brains can't fully process these temporal changes in smell because they happen so rapidly, much faster than an animal can sniff.Using behavioural experiments where mice were exposed to incredibly short bursts of odour, neural imaging, electrophysiology and computer models, the scientists found that mice can, in fact, detect very rapid fluctuations within odour plumes, at rates previously not thought possible. They also showed that mice can use this information to distinguish whether odours are coming from the same or different sources, even if they are very close to each other.This suggests that the mammalian olfactory system, responsible for the sense of smell, is also key in processing the awareness of physical space and surroundings, guiding decisions important to survival.Andreas Schaefer, senior author and group leader of the Sensory Circuits and Neurotechnology Laboratory at the Crick and Professor of Neuroscience at UCL says: "From an evolutionary point of view our findings make sense as they help to explain why there is a lot of computational power within the olfactory bulb, the part of the brain where the nose sends signals to. It isn't just processing chemicals from odours but can also calculate information about physical distance and source. It would have been odd for evolution to create such processing power in this part of the brain if it were not being used to help the species survive."In one key experiment, the scientists trained mice to detect whether two odours were coming from the same source or separate sources. The mice were able to correctly distinguish this difference even when the odours were released in short blips, lasting only a 40th of a second each (40 Hz).Tobias Ackels, postdoc in the Sensory Circuits and Neurotechnology Laboratory at the Crick says: "Previous research into the sense of smell was done on the assumption that mice couldn't distinguish the fine, fluctuating information in odour plumes."We've shown that mice can access and process this information -- this opens up a new dimension for studying the brain; we can run experiments that more effectively trigger neurons in a natural way and challenge the olfactory bulb. This will allow us to find out more about how this part of the brain works and how information about the world is extracted by neural circuits."As part of the study, the scientists designed new technologies including a high speed odour delivery device and equipment that can measure several odours simultaneously with extremely high precision.These innovations will enable more sophisticated work on the olfactory bulb, increasing our knowledge of how this brain region processes information about the environment and influences behaviour. Ultimately, the team aim to build understanding of how sensory circuits link the external world with internal thought and action.
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Biology
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May 5, 2021
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https://www.sciencedaily.com/releases/2021/05/210505113659.htm
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New bonobo genome fine tunes great ape evolution studies
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Chimpanzees and bonobos diverged comparatively recently in great ape evolutionary history. They split into different species about 1.7 million years ago. Some of the distinctions between chimpanzee (Pan troglodytes) and bonobo (Pan paniscus) lineages have been made clearer by a recent achievement in hominid genomics.
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A new bonobo genome assembly has been constructed with a multiplatform approach and without relying on reference genomes. According to the researchers on this project, more than 98% of the genes are now completely annotated and 99% of the gaps are closed.The high quality of this assembly is allowing scientists to more accurately compare the bonobo genome to that of other great apes -- the gorilla, orangutan, chimpanzee -- as well as to the modern human. All these species, as well as extinct, ancient, human-like beings, are referred to as hominids.Because chimpanzee and bonobo are also the closest living species to modern humans, comparing higher-quality genomes could help uncover genetic changes that set the human species apart.In a May 5 The multi-institutional project was led by Yafei Mao, of the Department of Genome Sciences at the University of Washington School of Medicine in Seattle, and Claudia R. Catacchio, of the Department of Biology at the University of Bari, Italy. The senior scientists were Evan Eichler, professor of genome sciences at the UW School of Medicine, and Mario Ventura of the University of Bari. Eichler is also a Howard Hughes Medical Institute investigator.By comparing the bonobo genome to that of other great apes, the researchers found more than 5,571 structural variants that distinguished the bonobo and chimpanzee lineages.The researchers explained in the paper, "We focused on genes that have been lost, changed in structure, or expanded in the last few million years of bonobo evolution."The great ape genome comparisons are also enabling researchers to gain new insights on what happened to the various ape genomes during and after the divergence or splitting apart into different species from a common ancestor.They were particularly interested in what is called incomplete lineage sorting. This is the less-than-perfect passing along of alleles into the separating populations as species diverge, as well as the loss of alleles or their genetic drift. Analyses of incomplete lineage sorting can help clarify gene evolution and the genetic relationships among present-day hominids.The higher-quality bonobo genome assembly enabled the researchers to generate a higher resolution map comparing incomplete lineage sorting in hominids. They identified regions that are inconsistent with the species tree. In addition, they estimate that 2.52% of the human genome is more closely related to the bonobo genome than the chimpanzee genome, and 2.55% of the human genome is more closely related to the chimpanzee genome than the bonobo genome.The total proportion based on incomplete lineage sorting analysis (5.07%) is almost double earlier estimates (3.1%)."We predict a greater fraction of the human genome is genetically closer to chimpanzees and bonobos compared to previous studies," the researchers note.The researchers took their incomplete lineage sorting analysis back 15 million years to include genome data from orangutan and gorilla. This increased the incomplete lineage sorting estimates for the hominid genomes to more than 36.5%, which is only slightly more than earlier predictions.Surprisingly, more than a quarter of these regions are distributed non-randomly, have elevated rates of amino acid replacement, and are enriched for particular genes with related functions such as immunity. This suggests that incomplete lineage sorting might work to increase diversity for specific regions.The new bonobo genome assembly is named for the female great ape whose DNA was sequenced, Mhudiblu, a current resident of the Wuppertal Zoo in Germany. The researchers estimate that sequence accuracy of the new assembly is about 99.97% to 99.99%, and closes about 99.5% of the 108,390 gaps in the previous bonobo assembly.The bonobo is one of the last great ape genomes to be sequenced with more advanced long-read genome sequence technologies, the researchers noted."Its sequence will facilitate more systematic comparisons between human, chimpanzee, gorilla and orangutan without the limitations of technological differences in sequencing and assembly of the original reference," according to the researchers.
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Biology
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May 5, 2021
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https://www.sciencedaily.com/releases/2021/05/210505111350.htm
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Meet the freaky fanged frog from the Philippines
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Researchers at the University of Kansas have described a new species of fanged frog discovered in the Philippines that's nearly indistinguishable from a species on a neighboring island except for its unique mating call and key differences in its genome.
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The KU-led team has just published its findings in the peer-reviewed journal "This is what we call a cryptic species because it was hiding in plain sight in front of biologists, for many, many years," said lead author Mark Herr, a doctoral student at the KU Biodiversity Institute and Natural History Museum and Department of Ecology & Evolutionary Biology. "Scientists for the last 100 years thought that these frogs were just the same species as frogs on a different island in the Philippines because they couldn't tell them apart physically. We ran a bunch of analyses -- and they do indeed look identical to the naked eye -- however, they are genetically isolated. We also found differences in their mating calls. They sound quite different. So, it was a case of using acoustics to determine that the species was different, as well as the new genetic information."Genetic samples of the new frog, known scientifically as Limnonectes beloncioi (or commonly as the Mindoro Fanged Frog), were collected years ago by KU scientists working in the field on Mindoro Island in the central Philippines but weren't analyzed until recently. Because of its nearly identical physical similarity to a fanged frog on the island of Palawan, called Acanth's Fanged Frog, it was assumed to be the same species."You can look at two different things, but to the human eye without intensive investigation they might seem the same," Herr said. "So, we took a bunch of measurements of hundreds of these frogs -- how long their digits were specifically, how wide the tip of their toe was, the length of one specific segment of their leg, the diameter of their eye -- in order to compare populations statistically, even if we thought they look the same. We ran statistical analyses on body shape and size, including a principal component analysis which uses all the measurements at once to compare the frog morphology in multivariate space. After all that, just like the scientists before us, we found nothing to differentiate the frogs based on the shape of their bodies and their size."However, because the fanged frogs inhabit islands separated by miles and miles of ocean, the researchers had doubts they were the same species, in part because they had different-sounding calls. They decided to analyze the frogs' genome and determined the Mindoro Fanged Frog qualified as its own distinct species."We ran genetic analyses of these frogs using some specific genetic markers, and we used a molecular clock model just to get a very basic estimate how long we thought that these frogs may have been separated from one another," Herr said. "We found they're related to each other, they are each other's close relatives, but we found they'd been separate for two to six million years -- it's a really long time for these frogs. And it's very interesting that they still look so similar but sound different."The KU graduate student specializes in studying the many species of fanged frog across Southeast Asia, where he's carried out extensive fieldwork. He said the frogs' fangs likely are used in combat for access to prime mating sites and to protect themselves from predators. The Mindoro Fanged Frog, a stream frog, is sometimes hunted by people for food.But the frog's characteristic call, different from Acanth's Fanged Frog, proved difficult for researchers to record."They're really wary of us when we're out there with our sound recorders trying to get recordings of these frogs -- that's a really tough aspect, and we were lucky in this project that we had people over many years that were out there and had recorded both of these frogs on Palawan and Mindoro. So, we had recordings from both islands, and that's kind of rare with this group of fanged frogs because people eat them. They call at night, but the second a flashlight or human voice wanders into the equation they're just going to take off -- because they know that they can be killed by people."Herr's description of the Mindoro Fanged Frog continues a long tradition of KU field research into the herpetological biodiversity of the Philippines and Southeast Asia, according to his faculty adviser Rafe Brown, professor of ecology & evolutionary biology and curator-in-charge of the Herpetology Division of the Biodiversity Institute and Natural History Museum."Mark's discovery reinforces a lesson we've learned over and over through the years -- things we thought we knew, combined with new information, emerge to teach us something completely unexpected," Brown said. "A century ago, KU professor Edward Taylor identified the Mindoro Island population as Acanth's Fanged Frog, the same species as he had named, a few years before, from Palawan Island -- an arrangement that made very little sense. Zoom forward a hundred years, and we find with new technology, genetic information and bioacoustic data that the two islands' populations are actually very well-differentiated, as we would expect. But not morphologically; their physical characteristics have not diverged. This is a case in which the formation of species has not been accompanied by morphological differentiation -- so called 'cryptic speciation.'"
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Biology
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May 5, 2021
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https://www.sciencedaily.com/releases/2021/05/210505111311.htm
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3D bioprinting technique controls cell orientation
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3D bioprinting can create engineered scaffolds that mimic natural tissue. Controlling the cellular organization within those engineered scaffolds for regenerative applications is a complex and challenging process.
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Cell tissues tend to be highly ordered in terms of spatial distribution and alignment, so bioengineered cellular scaffolds for tissue engineering applications must closely resemble this orientation to be able to perform like natural tissue.In The team uses static mixing to fabricate striated hydrogel fibers formed from packed microfilaments of different hydrogels. In this structure, some compartments provide a favorable environment for cell proliferation, while others act as morphological cues directing cell alignment. The millimeter-scale printed fiber with the microscale topology can rapidly organize the cells toward faster maturation of the engineered tissue."This strategy works on two principles," said Ali Tamayol, coauthor and an associate professor in biological engineering at UConn Health. "The formation of topographies is based on the design of fluid within nozzles and controlled mixing of two separate precursors. After crosslinking, the interfaces of the two materials serve as 3D surfaces to provide topographical cues to cells encapsulated within the cell permissive compartment."Extrusion-based bioprinting is the most widely used bioprinting method. In extrusion-based bioprinting, the printed fibers are typically several hundreds of micrometers in size with randomly oriented cells, so a technique providing topographical cues to the cells within these fibers to direct their organization is highly desirable.Conventional extrusion bioprinting also suffers from high shear stress applied to the cells during the extrusion of fine filaments. But the fine scale features of the proposed technique are passive and do not compromise other parameters of the printing process.To direct cellular organization, according to the team, extrusion-based 3D-bioprinted scaffolds should be made from very fine filaments."It makes the process challenging and limits its biocompatibility and the number of materials that can be used, but with this strategy larger filaments can still direct cellular organization," said Tamayol.This bioprinting technique "enables production of tissue structures' morphological features -- with a resolution up to sizes comparable to the cells' dimension -- to control cellular behavior and form biomimetic structures," Tamayol said. "And it shows great potential for engineering fibrillar tissues such as skeletal muscles, tendons, and ligaments."
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Biology
| 2,021 |
May 5, 2021
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https://www.sciencedaily.com/releases/2021/05/210505102033.htm
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New Monarch butterfly breeding pattern inspires hope
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A count of the Western Monarch butterfly population last winter saw a staggering drop in numbers, but there are hopeful signs the beautiful pollinators are adapting to a changing climate and ecology.
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The population, counted by citizen scientists at Monarch overwintering locations in southern California, dropped from around 300,000 three years ago to just 1,914 in 2020, leading to an increasing fear of extinction. However, last winter large populations of monarchs were found breeding in the San Francisco and Los Angeles areas. Prior to last winter, it was unusual to find winter breeding by monarchs in those locations."There's more to it than just counting overwintering butterflies," said David James, an associate professor in Washington State University's Department of Entomology. "It seems that Monarchs are evolving or adapting, likely to the changing climate, by changing their breeding patterns."The larger numbers of reported sightings of winter breeding monarchs around the San Francisco Bay area prompted James to write a new commentary article in the journal The only way to count breeding populations last winter was to look at online citizen scientist observations, supported by limited field work, James said."There has been a huge increase in caterpillars in the Bay area, indicating that those populations are breeding," he said. "The data are limited and preliminary, but we think the population is at least double what has been reported. However, it's hard to tell since they're dispersed over much of California."James said this pattern of Monarch butterflies adapting looks familiar to him because he saw something similar while working on his Ph.D. dissertation over 40 years ago in Sydney, Australia.In the late 1970s, the Monarch population in Australia saw huge declines. Scientists thought it was due to habitat loss, a common guess at one factor causing population declines in the western U.S. now."In Australia, Monarchs haven't gone extinct," James said. "They've just adapted and moved along with a smaller population. And there's no effort to preserve them there because they aren't a native species. They're just very resilient."Though the declining population is a concern, James believes Monarchs in the western U.S. will experience a similar plateau and not go extinct."San Francisco is very similar, climate-wise, to the area around Sydney," James said. "And seeing this winter breeding, which is something new we saw in Australia in the late 1970s, leads me to think that Monarchs will adapt well to the changing climate in the western US."He is now working with citizen scientists to collect more data on winter breeding in California that can show this evolution and adaptability."The Monarch is like the cockroach of butterflies," James said. "It's very persistent and adaptable all around the world. The population decline is very worrying, but I remain optimistic that it will persist in the western US, although maybe at lower levels than before."Monarchs are iconic and very popular, basically the poster insect when anyone thinks about butterflies. Their large orange wings with black accents are immediately recognizable. They're also important pollinators all along their migration routes, which in the western U.S. is basically from the Pacific Northwest to southern California. The loss of habitat for their favored milkweed is one reason for their dramatic population decline."Beyond their beauty is their role in ecology," James said. "They pollinate and they are also an important part of the food chain. There's a whole range of reasons why people care about them and don't want them to go extinct."James is continuing his long-running Monarch tagging program, in which the butterflies are raised and tagged by people in the Northwest, including inmates at a prison, then released so they can migrate south for winter. He thinks he'll find more tagged monarchs around the Bay area in breeding, instead of in non-breeding overwintering colonies, as happened last winter.He plans to work with citizen scientists to collect and crunch the data to come to solid scientific conclusions. Until then, he maintains his optimism about how well these butterflies adapt."We don't know if this adaptation will continue and how successful it will be," James said. "The western Monarch population is quite precarious right now. It's at a tipping point, and something is happening. We need to do more work to find out exactly what is happening."
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Biology
| 2,021 |
May 5, 2021
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https://www.sciencedaily.com/releases/2021/05/210505102027.htm
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Tracking down the tiniest of forces: How T cells detect invaders
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T-cells play a central role in our immune system: by means of their so-called T-cell receptors (TCR) they make out dangerous invaders or cancer cells in the body and then trigger an immune reaction. On a molecular level, this recognition process is still not sufficiently understood.
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Intriguing observations have now been made by an interdisciplinary Viennese team of immunologists, biochemists and biophysicists. In a joint project funded by the Vienna Science and Technology Fund and the FWF, they investigated which mechanical processes take place when an antigen is recognized: As T cells move their TCRs pull on the antigen with a tiny force -- about five pico-newtons (5 x 10-12 or 0.0000000005 newtons). This is not only sufficient to break the bonds between the TCRs and the antigen, it also helps T cells to find out whether they are interacting indeed with the antigen they are looking for. These results have now been published in the scientific journal "Each T cell recognizes one specific antigen particularly well," explains Johannes Huppa, biochemist and immunology professor at MedUni Vienna."To do so, it features around 100,000 TCRs of the same kind on its surface."When viruses attack our body, infected cells present various fragments of viral proteins on their surface. T cells examine such cells for the presence of such antigens. "This works according to the lock-and-key principle," explains Johannes Huppa. "For each antigen, the body must produce T cells with matching TCRs. Put simply, each T-cell recognizes only one specific antigen to then subsequently trigger an immune response."That particular antigen, or more precisely, any antigenic protein fragment presented that exactly matches the T cell's TCR, can form a somewhat stable bond. The question that needs to be answered by the T cell is: how stable is the binding between antigen and receptor?"Let's say we wish to find out whether a surface is sticky -- we then test how stable the bond is between the surface and our finger," says Gerhard Schütz, Professor of Biophysics at TU Wien. "We touch the surface and pull the finger away until it comes off. That's a good strategy because this pull-away behavior quickly and easily provides us information about the attractive force between the finger and the surface."In principle, T-cells do exactly the same. T cells are not static, they deform continuously and their cell membrane is in constant motion. When a TCR binds to an antigen, the cell exerts a steadily increasing pulling force until the binding eventually breaks. This can provide information about whether it is the antigen that the cell is looking for."This process can actually be measured, even at the level of individual molecules," says Dr. Janett Göhring, who was active as coordinator and first author of the study at both MedUni Vienna and TU Vienna. "A special protein was used for this, which behaves almost like a perfect nano-spring, explain the two other first authors Florian Kellner and Dr. Lukas Schrangl from MedUni Vienna and TU Vienna respectively: "The more traction is exerted on the protein, the longer it becomes. With special fluorescent marker molecules, you can measure how much the length of the protein has changed, and that provides information about the forces that occur." In this way, the group was able to show that T cells typically exert a force of up to 5 pico-newtons -- a tiny force that can nevertheless separate the receptor from the antigen. By comparison, one would have to pull on more than 100 million such springs simultaneously to feel stickiness with a finger."Understanding the behavior of T cells at the molecular level would be a huge leap forward for medicine. We are still leagues away from that goal," says Johannes Huppa. "But," adds Gerhard Schütz, "we were able to show that not only chemical but also mechanical effects play a role. They have to be considered together."
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Biology
| 2,021 |
May 5, 2021
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https://www.sciencedaily.com/releases/2021/05/210505094424.htm
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Legendary Sargasso Sea may be sea turtles' destination during mysterious 'lost years'
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New research indicates that the legendary Sargasso Sea, which includes part of the Bermuda Triangle and has long featured in fiction as a place where ships go derelict, may actually be an important nursery habitat for young sea turtles.
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In a study led by a University of Central Florida researcher and published today in the journal The study was the first time that green sea turtles have been tracked during their early "lost years," which is defined as the time between hatching from their nests along Florida's Atlantic coast and heading into the ocean and their "teenage years," when they return to coastal habitats after several years in the open ocean. Not much is known about where sea turtles go during these years, which is where the "lost years" description comes from. The new findings echo the team's previous research that showed baby loggerhead sea turtles arrive at the Sargasso Sea.The results are helping to solve the mystery of where the turtles go and will also inform efforts to conserve the threatened animals, especially during their delicate first years at sea.Florida's Atlantic coastline is a major nesting area for green and loggerhead sea turtles, which are iconic species in conservation efforts and important for their role in helping maintain ocean ecosystems, says UCF Biology Associate Professor Kate Mansfield, who led the study in collaboration with Jeanette Wyneken at Florida Atlantic University.Scientists have long assumed that after hatching and going into the ocean, baby sea turtles would passively drift in sea currents, such as those circulating around the Atlantic Ocean, and ride those currents until their later juvenile years."That green turtles and loggerheads would continue in the currents, but that some might leave the currents and go into the Sargasso Sea was not ever considered or predicted by long-held hypotheses and the assumptions in the field," Mansfield says. "We found that the green turtles actively oriented to go into the Sargasso Sea and in even greater numbers than the loggerheads tracked in our earlier work. Granted, our sample sizes aren't huge, but enough turtles made this journey that it really throws into question our long-held beliefs about the early lives of sea turtles."The Sargasso Sea, located off the east coast of the U.S. in the North Atlantic Ocean, has often been featured erroneously in popular culture, such as in Jules Verne's Twenty Thousand Leagues under the Sea, as a place where ships could become derelict when trying to travel through thick mats of the floating, brown, Sargassum algae for which it is named. In reality, the Sargassum algae clumps together in distinct patches so it poses little threat to vessels navigating through the area.The researchers were able to track the turtles by attaching advanced, solar-powered tracking devices, about an inch in length, to their shells. This also required determining the optimum adhesive for applying the sensor, which was different for the green sea turtles than for loggerheads because of the greens' waxier-feeling shells. The tracking device is designed to fall off after a few months and does not hurt the turtles or inhibit the turtles' shell growth or behavior, Mansfield says.In the current study, 21 green sea turtles less than a year old, had transmitters affixed and were released into the Gulf Stream ocean currents about 10 miles offshore from the beach where they were born. The turtle release dates were from 2012 to 2013, and the researchers were able to track the turtles for up to 152 days.Of the 21 turtles, 14 departed the Gulf Stream and the North Atlantic gyre of circulating currents and entered the western or northern Sargasso Sea region in the western Atlantic Ocean, according to the study. This is compared to seven out of 17 loggerhead turtles that left the Gulf Stream and entered the Sargasso Sea in the previous study.Wyneken, a professor of biological sciences and director of Florida Atlantic University's Marine Science Laboratory at Gumbo Limbo Environmental Complex, worked with Mansfield to collect, raise, tag and release the turtles.She says the research is important because it sheds light on where the baby turtles go during a delicate period in their lives."These studies in which we learn where little sea turtles go to start growing up are fundamental to sound sea turtle conservation," Wyneken says. "If we don't know where they are and what parts of the ocean are important to them, we are doing conservation blindfolded."Jiangang Luo, PhD, a scientist with the Tarpon Bonefish Research Center at the University of Miami's Rosenstiel School of Marine and Atmospheric Science and study co-author, has a background in mathematical biology, oceanography and advanced scientific data visualization. As part of the research team, he helped process and analyze the data and graphed and animated the results."It feels great to see how the little turtles are traveling and utilizing the ocean," Luo says. "The ocean is our future, and we must have the ocean to save the sea turtles."The Sargasso Sea Commission, which works as a steward for the area with support from multiple governments and collaborating partners, will use data from the research as part of its upcoming ecosystem diagnostic project, says the commission's Programme Manager Teresa Mackey.The project will quantify threats and their potential impact on the Sargasso Sea, including climate change, plastics pollution and commercial activities, as well as investigate ways to counter challenges the area faces and establish a baseline for ongoing monitoring and adaptive management."Dr. Mansfield's research into the critical habitat that this area provides for turtles early in their life cycle gives concrete evidence of the importance of the Sargasso Sea for endangered and critically endangered species and is one of the many reasons why conservation of this high-seas ecosystem is vitally important for marine biodiversity," Mackey says.UCF's Marine Turtle Research Group, which Mansfield directs, has been one of the commission's collaborators since 2017.Mansfield says next steps for the "lost years" research will include looking more closely at differences in orientation and swimming behavior between turtle species, understanding the role Sargassum plays in early sea turtle development, and testing newer, smaller, and more accurate tracking devices to learn more about the places the baby turtles go and how they interact with their environment.The research was funded largely through the Florida Sea Turtle Specialty License Plate grants program, Disney Conservation Fund and the Save Our Seas Foundation.
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Biology
| 2,021 |
May 5, 2021
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https://www.sciencedaily.com/releases/2021/05/210505075052.htm
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Cryptic sense of orientation of bats localized: the sixth sense of mammals lies in the eye
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Mammals see with their eyes, hear with their ears and smell with their nose. But which sense or organ allows them to orient themselves on their migrations, which sometimes go far beyond their local foraging areas and therefore require an extended ability to navigate? Scientific experiments led by the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW), published together with Prof. Richard A. Holland (Bangor University, UK) and Dr. Gun?rs P?tersons (Latvia University of Life Sciences and Technologies) now show that the cornea of the eyes is the location of such an important sense in migrating bats. If the cornea is anaesthetised, the otherwise reliable sense of orientation is disturbed while light detection remains unimpaired. The experiment suggests the localisation of a magnetic sense in mammals. The paper is published in the scientific journal
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A research team led by Dr Oliver Lindecke and PD Dr Christian Voigt from Leibniz-IZW demonstrated for the first time that environmental signals that are important for navigating over long distances are picked up via the cornea of the eyes. They conducted experiments with Nathusius' bats (Pipistrellus nathusii) during the late summer migration period. In bats of one test group, the scientists locally anaesthetised the cornea with a drop of oxybuprocaine. This surface anaesthetic is widely used in ophthalmology, where it is used to temporarily desensitise the patients' cornea when eyes of humans or animals get overly irritated. Effects on orientation, however, had not been previously recorded. In another test group of bats, the research team anaesthetised the cornea of only one eye. The individuals in the control group were not anaesthetised, but instead received an isotonic saline solution as eye drops. All animals in this scientific experiment were captured within a migration corridor at the coastline of the Baltic Sea and released singly in the open field 11 kilometres inland from the capture site immediately after treatment. The scientists first used bat detectors to make sure that there were no other bats above the field at the time of release that the test animals could have followed. The person observing the direction of movement of released bats was unaware about how bats were treated experimentally. "The control group and the group with unilateral corneal anaesthesia oriented themselves clearly in the expected southerly directions, whereas the bats with bilateral anaesthetised corneas flew off in random directions," explains Dr Oliver Lindecke, first author of the paper. "This evident difference in behaviour suggests that corneal anaesthesia disrupted a sense of direction, yet orientation apparently still works well with one eye." As corneal treatment wears off after a short time, the bats were able to resume their journeys south after the experiment. "We observed here for the first time in an experiment how a migrating mammal was literally blown off course -- a milestone in behavioural and sensory biology that allows us to study the biological navigation system in a more targeted way."In order to rule out the possibility that the anaesthetisation of the cornea also affects the sense of sight and that the scientists would thus come to the wrong conclusions, they carried out a complementary test. Once again divided into experimental and control groups, they tested whether the response of bats to light changed after anaesthesia of the corneas on one or both sides. "We know from previous research that bats prefer an illuminated exit when leaving a simple Y-shaped labyrinth," explains PD Dr Christian Voigt, head of the Leibniz-IZW Department of Evolutionary Ecology. "In our experiment, the animals with one-sided or two-sided anaesthesia also showed this preference; we therefore can rule out that the ability to see light was altered after corneal treatment. The ability to see light would of course also influence long-distance navigation."Many vertebrates such as bats, dolphins, whales, fish and turtles, for example, are able to safely navigate in darkness, whether it is under the open night sky, when it is cloudy at night or in caves and tunnels as well as in the depths of the oceans. For many decades, scientists have been searching for the sense or a sensory organ that enables animals to perform orientation and navigation tasks that seemed difficult to imagine for people. A magnetic sense, so far only demonstrated in a few mammals but poorly understood, is an obvious candidate. Experiments suggest that iron oxide particles within cells may act as "microscopic compass needles," as is the case in some species of bacteria.Recent laboratory experiments on Ansell's mole-rat, relatives of the well-known naked mole rats that spend their lives in elaborate underground tunnel systems, suggest that the magnetic sense is located in the eye. Such a (magnetic) sense of orientation has not been checked in migratory mammals nor has it been possible to identify the specific organ or tissue which could provide the morphological basis for the required sensory receptors. The experiments of the team around Lindecke and Voigt now provide, for the first time, reliable data for the localisation of a sense of orientation in free-ranging, migratory mammals. Exactly what the sense in the cornea of the bats looks like, how it works and whether it is the long sought-after magnetic sense must be shown in future scientific investigations.
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Biology
| 2,021 |
May 5, 2021
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https://www.sciencedaily.com/releases/2021/05/210505075016.htm
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Small things can have a major effect on the prevention of biodiversity loss
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The population growth of an endangered butterfly species is greatest in habitats with microclimatic variability, demonstrates a study carried out collaboratively by the Faculty of Biological and Environmental Sciences and the Helsinki Institute of Life Science of the University of Helsinki as well as the Finnish Environment Institute.
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Insects are often very restricted in their capacity for movement. In many species, specific stages of life are spent entirely immobile, making them dependent on the temperature and moisture conditions of their immediate surroundings. In the Åland Islands on the southwest coast of Finland, Glanville fritillary butterflies ("We investigated how varying microclimates affect larval growth and survival in the spring after the overwintering. We found that warm and sunny days in March woke up the larvae and made them look for food. However, very little food was to be found, since the few warm days in early spring were followed by a cool April, with the growing season of the larval host plants only beginning in earnest in May," says doctoral researcher Susu Rytteri from the University of Helsinki's Research Centre for Ecological Change. She defended her thesis at the end March 2021.It was observed that, in sunny and warm microclimates, larvae grew faster but also perished in large numbers because of lack of food. In cooler and shadier microclimates, larval growth was slow, a boost to the sufficiency of food: food plants had the time to grow in sync with the nutritional requirements of the larvae. Comprehensive survey data from the Åland Islands also demonstrated that Glanville fritillary populations grew the most in meadows where their larvae inhabited varying microclimates."The growth of butterfly populations increased when larval groups were located in particularly warm spots on sunny southward slopes. At the same time, the larvae also benefited from cooler and shaded microclimates. Due to the unpredictability and variability of weather conditions, the optimal egg-laying strategy for insects would appear to be laying eggs in varying microclimates which have the capacity to protect their immobile offspring from unfavourable conditions. The problem is that habitats have declined in number and become increasingly uniform. Consequently, varying microclimates are not necessarily on offer," Rytteri says.Promoting microclimatic variability in your backyard helps insects and other animals. The sunniest spot in the yard can be turned into an even warmer place for sunbathing by, for example, constructing a section of stone wall that stores heat and offers protective crevices for small creatures. An oasis in the shade can be built in the coolest location in the yard by planting lush plants that thrive away from the sun and by adding a water element that is not only pleasing to the human eye but also serves as a watering place for animals during dry spells."Butterflies benefit from diverse plants, and in butterfly gardens, the goal should be floral splendour stretching from early spring long into the autumn. Many garden plants are good melliferous plants, that is, plants rich in pollen and nectar, but wild meadow plants shouldn't be overlooked either. Trees, bushes, rocks and knolls form variable microclimates and offer protection from unfavourable weather conditions," Rytteri points out.
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Biology
| 2,021 |
May 4, 2021
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https://www.sciencedaily.com/releases/2021/05/210504191551.htm
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A trait of the rare few whose bodies naturally control HIV: 'trained' immune cells
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Immunity often calls to mind the adaptive immune response, made up of antibodies and T cells that learn to fight specific pathogens after infection or vaccination. But the immune system also has an innate immune response, which uses a set number of techniques to provide a swift, non-specialized response against pathogens or support the adaptive immune response.
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In the past few years, however, scientists have found that certain parts of the innate immune response can, in some instances, also be trained in response to infectious pathogens, such as HIV. Xu Yu, MD, a Core Member of the Ragon Institute of MGH, MIT and Harvard, and colleagues recently published a study in the "Using RNA-sequencing technology, we were able to identify one long-noncoding RNA called MIR4435-2HG that was present at a higher level in elite controllers' myeloid dendritic cells, which have enhanced immune and metabolic states," says Yu. "Our research shows that MIR4435-2HG might be an important driver of this enhanced state, indicating a trained response."Myeloid dendritic cells' primary job is to support T cells, which are key to the elite controllers' ability to control HIV infection. Since MIR4435-2HG was found in higher levels only in cells from elite controllers, Yu explains, it may be part of a learned immune response to infection with HIV. Myeloid dendritic cells with increased MIR4435-2HG also had higher amounts of a protein called RPTOR, which drives metabolism. This increased metabolism may allow the myeloid dendritic cells to better support the T cells controlling the HIV infection."We used a novel sequencing technology, called CUT&RUN, to study the DNA of these cells," says postdoctoral fellow Ciputra Hartana, MD, PhD, the paper's first author. "It allowed us to study epigenetic modifications like MIR4435-2HG, which are molecules that bind to the DNA and change how, or if, the DNA is read by the cell's machinery."The team found that MIR4435-2HG might work by attaching to the DNA near the location of the RPTOR gene. The bound MIR4435-2HG would then encourage the cell's machinery to make more of the RPTOR protein, using the instructions found in the RPTOR gene. This type of epigenetic modification, a trained response to HIV infection, would allow the myeloid dendritic cells to stay in an increased metabolic state and therefore provide long-term support to the T cells fighting the virus."Myeloid dendritic cells are very rare immune cells, accounting for only 0.1-0.3% of cells found in human blood," says Yu. "We were fortunate and thankful to have access to hundreds of millions of blood cells from the many study participants who have donated their blood to support our HIV research. These donations were key to making this discovery."Understanding exactly how elite controllers' immune systems can control HIV is a key part of HIV cure research. If scientists can understand how elite controllers suppress this deadly virus, they may be able to develop treatments that allow other people living with HIV to replicate the same immune response, removing the need for daily medication to control the virus and achieving what is known as a functional cure.
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Biology
| 2,021 |
May 4, 2021
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https://www.sciencedaily.com/releases/2021/05/210504112631.htm
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Pyrosomes: Enigmatic marine inhabitants with an important role in the Cabo Verde ecosystem
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Pyrosomes, named after the Greek words for 'fire bodies' due their bright bioluminescence, are pelagic tunicates that spend their entire lives swimming in the open ocean. They are made up of many smaller animals, known as zooids, that sit together in a tubular matrix, known as tunic (hence the name pelagic tunicates). Because they live in the open ocean, they generally go unnoticed. In spite of this, increasing research points to their importance in marine environments, as they can form dense blooms that impact food web dynamics and contribute to the movement and transformation of organic carbon.
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The study conducted with GEOMAR research vessel POSEIDON in 2018 and 2019 in the vicinity of the Cabo Verde Islands, of which the results have now been published in the international journal "Because we combined underwater observations, sampling and genetic analyses, we were able to gain several new insights into pyrosome ecology," says lead author Vanessa Stenvers, from GEOMAR. During the expedition, the organisms were observed directly with the research submersible JAGO, and also studied via a pelagic towed camera system, PELAGIOS, as well as by net and water sampling."Our study shows that pyrosomes form an important biological substrate in the water column that other animals use for settlement, shelter and/or as a food source," explains Vanessa Stenvers. "We have estimated that Pyrosoma atlanticum provides up to 0.28 m2 of substrate area per square metre of total area during a bloom period. This is a huge number if you consider that there are little physical features in the water column besides the animals that live there," says the marine biologist.Thanks to the underwater observations, the team also discovered several new species interactions, including the jellyfish Drymonema gorgo, which fed on pyrosomes, and a yet undescribed oxycephalid amphipod that was frequently observed on pyrosomes. Upon closer inspection, these amphipods had removed individual zooids to create a cavity in the colony into which they retreated upon disturbance.Pyrosome blooms were found to be related to high values of chlorophyll. Since the filter-feeding organisms directly consume microalgae, they profit from upwelling conditions that are found both on the lee side of the islands as well as in mid-ocean eddies. The latter are circular currents that can move cold nutrient-rich water from deeper depths up to the surface."Furthermore, we found that Pyrosoma atlanticum plays an important role in how about the vertical transport of organic carbon in the waters around the Cabo Verde Islands," explains Dr. Henk-Jan Hoving, who leads the Deep Sea Biology research group at GEOMAR and is senior co-author of the study. Pyrosomes migrate up and down the water column daily to feed in the productive upper marine layers at night. At dusk, they migrate back to deeper water layers. During this migration, they actively transport their feces to these depths, while also releasing carbon through respiration. "In addition to observations and theoretical estimates, we have been able to show with the detection of environmental DNA from water samples that pyrosome material can also be detected below their migration range, i.e. sinking into the deep ocean," explains Dr Hoving.Another way for pyrosomes to contribute to the carbon cycle is by deposition of dead and dying colonies to the seafloor, where they act as food for organisms living there. "From the submersible JAGO, I observed that pyrosomes were consumed on the seafloor by decapods, such as large crabs, shrimps and hermit crabs, illustrating their important role as food for seabed scavengers," says marine biologist and co-author Rui Freitas of the Marine Institute at the Universidade Técnica do Atlântico, Mindelo, Cabo Verde. "Thus, the present results illustrate the important and versatile ecological role of Pyrosoma atlanticum in the ocean around the Cabo Verde Islands, affecting both pelagic and benthic ecosystems," Henk-Jan Hoving concludes.
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Biology
| 2,021 |
May 4, 2021
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https://www.sciencedaily.com/releases/2021/05/210504112535.htm
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Chemical 'nose' sniffs critical differences in DNA structures
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Small changes in the structure of DNA have been implicated in breast cancer and other diseases, but they've been extremely difficult to detect -- until now.
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Using what they describe as a "chemical nose," UC Riverside chemists are able to "smell" when bits of DNA are folded in unusual ways. Their work designing and demonstrating this system has been published in the journal "If a DNA sequence is folded, it could prevent the transcription of a gene linked to that particular piece of DNA," said study author and UCR chemistry professor Wenwan Zhong. "In other words, this could have a positive effect by silencing a gene with the potential to cause cancer or promote tumors."Conversely, DNA folding could also have a negative effect."DNA folds could potentially keep viral proteins from being produced to minimize immune response," Zhong said.Studying how these folds might impact living beings, either positively or negatively, first requires scientists to detect their presence. To do that, UCR organic chemistry professor Richard Hooley and his colleagues modified a concept that has previously been used to sense other things, such as chemical components in different vintages of wine.The chemicals in the system could be designed to look for nearly any kind of target molecule. However, the way the "nose" is typically used, it could not detect DNA. Only once Hooley's group added additional, nonstandard components could the nose sniff out its DNA target."Humans detect smells by inhaling air containing odor molecules that bind to multiple receptors inside the nose," Hooley explained. "Our system is comparable because we have multiple receptors able to interact with the DNA folds we're looking for."The chemical nose is composed of three parts: host molecules, fluorescent guest molecules, and DNA, which is the target. When the desired folds are present, the guest glows, alerting scientists to their presence in a sample.DNA is made of four nucleic acids: guanine, adenine, cytosine and thymine. Most of the time, these acids form a double helix structure resembling a ladder. Guanine-rich regions sometimes fold in a different manner, creating what's called a G-quadruplex.Parts of the genome that form these quadruplex structures are extremely complex, though UC Riverside researchers have discovered that their folds are known to regulate gene expression, and they play a key role in keeping cells healthy.For this experiment, the researchers wanted to demonstrate that they could detect one specific type of quadruplex composed of four guanines. Having done so, Zhong said the research team will try to build on their success."Now we think we can do more," she said. "There are other three-dimensional structures in DNA, and we want to understand those as well."The researchers will examine how forces that damage DNA affect the ways they fold. They will also study RNA folding because RNA carries out important functions in a cell."RNA has even more complex structures than DNA, and is more difficult to analyze, but understanding its structure has great potential for disease research," Zhong said.
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Biology
| 2,021 |
May 4, 2021
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https://www.sciencedaily.com/releases/2021/05/210504112523.htm
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Cayman Islands sea turtles back from the brink
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Sea turtles in the Cayman Islands are recovering from the brink of local extinction, new research shows.
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Monitoring from 1998-2019 shows loggerhead and green turtle nest numbers increased dramatically, though hawksbill turtle nest numbers remain low.In the first counts in 1998-99, just 39 sea turtle nests were found in total on the three islands. By 2019, the figure was 675.Captive breeding of green turtles and inactivity of a traditional turtle fishery due to tightening of restrictions in 2008 contributed to this -- but populations remain far below historical levels and still face threats including illegal hunting.The study was carried out by the Cayman Islands Department of Environment and the University of Exeter."Our findings demonstrate a remarkable recovery for sea turtle populations that were once thought to be locally extinct," said Dr Janice Blumenthal, of the Cayman Islands Department of Environment."A combination of factors is thought to have led to this conservation success story."It is likely that a captive breeding operation by the Cayman Turtle Farm (now the Cayman Turtle Centre) drove the increase in Grand Cayman's green turtle population in the early years of monitoring."For loggerhead turtles, the most important factor was the restrictions placed on the legal turtle fishery in 2008."Dr Jane Hardwick, also of the Cayman Islands Department of Environment, added: "For both species, the recovery was assisted by protection efforts by the Cayman Islands Department of Environment on nesting beaches, including patrols by conservation officers to reduce illegal hunting."However, our study finds that illegal take is an ongoing threat, with a minimum of 24 turtles taken from 2015-19, many of which were nesting females."Artificial lighting on nesting beaches, which can direct hatchlings away from the sea, increased over the period of our study."Additionally, as highly migratory endangered species, sea turtles are influenced by threats and conservation efforts outside of the Cayman Islands, showing a need for international co-operation in sea turtle management."Historically, the Cayman Islands had among the world's largest sea turtle nesting populations, with turtles numbering in the millions. By the early 1800s, the populations had collapsed due to human overexploitation.The new study shows that, despite reaching critically low levels, nesting populations of green and loggerhead turtles have recovered significantly.Hawksbill turtle nest numbers have not increased in tandem with loggerhead and green turtles -- with a maximum of 13 hawksbill nests recorded in a single monitoring season.Information on turtle nests is being used by the Cayman Islands authorities to target management efforts.This includes "turtle-friendly lighting" initiatives, and a greater level of habitat protection for key areas has been proposed under the National Conservation Law of the Cayman Islands.Professor Brendan Godley, of the University of Exeter, said: "I was fortunate to have been involved in establishing the turtle monitoring programme with the Department of Environment in the Cayman Islands back in 1998 and it is fantastic to see how protection and awareness has resulted in an increase in nesting turtles."The wonderful team and leadership of the Department of Environment have been instrumental in driving the monitoring and conservation."Department of Environment Director Gina Ebanks-Petrie said: "We are extremely grateful to the many volunteers, interns, property owners, businesses, organisations and members of the public who have assisted with sea turtle conservation efforts over the past two decades."Sea turtles are a national symbol of the Cayman Islands and our community has come together to demonstrate our commitment to their protection. This research gives us essential information for strategically targeted management efforts to secure future survival of these populations."
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Biology
| 2,021 |
May 3, 2021
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https://www.sciencedaily.com/releases/2021/05/210503172844.htm
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Speeding new treatments
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A year into the COVID-19 pandemic, mass vaccinations have begun to raise the tantalizing prospect of herd immunity that eventually curtails or halts the spread of SARS-CoV-2. But what if herd immunity is never fully achieved -- or if the mutating virus gives rise to hyper-virulent variants that diminish the benefits of vaccination?
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Those questions underscore the need for effective treatments for people who continue to fall ill with the coronavirus. While a few existing drugs show some benefit, there's a pressing need to find new therapeutics.Led by The University of New Mexico's Tudor Oprea, MD, PhD, scientists have created a unique tool to help drug researchers quickly identify molecules capable of disarming the virus before it invades human cells or disabling it in the early stages of the infection.In a paper published this week in "To some extent this replaces (laboratory) experiments, says Oprea, chief of the Translational Informatics Division in the UNM School of Medicine. "It narrows the field of what people need to focus on. That's why we placed it online for everyone to use."Oprea's team at UNM and another group at the University of Texas at El Paso led by Suman Sirimulla, PhD, started work on the REDIAL-2020 tool last spring after scientists at the National Center for Advancing Translational Sciences (NCATS) released data from their own COVID drug repurposing studies."Becoming aware of this, I was like, 'Wait a minute, there's enough data here for us to build solid machine learning models,'" Oprea says. The results from NCATS laboratory assays gauged each molecule's ability to inhibit viral entry, infectivity and reproduction, such as the cytopathic effect -- the ability to protect a cell from being killed by the virus.Biomedicine researchers often tend to focus on the positive findings from their studies, but in this case, the NCATS scientists also reported which molecules had no virus-fighting effects. The inclusion of negative data actually enhances the accuracy of machine learning, Oprea says."The idea was that we identify molecules that fit the perfect profile," he says. "You want to find molecules that do all these things and don't do the things that we don't want them to do."The coronavirus is a wily adversary, Oprea says. "I don't think there is a drug that will fit everything to a T." Instead, researchers will likely devise a multi-drug cocktail that attacks the virus on multiple fronts. "It goes back to the one-two punch," he says.REDIAL-2020 is based on machine learning algorithms capable of rapidly processing huge amounts of data and teasing out hidden patterns that might not be perceivable by a human researcher. Oprea's team validated the machine learning predictions based on the NCATS data by comparing them against the known effects of approved drugs in UNM's DrugCentral database.In principle, this computational workflow is flexible and could be trained to evaluate compounds against other pathogens, as well as evaluate chemicals that have not yet been approved for human use, Oprea says."Our main intent remains drug repurposing, but we're actually focusing on any small molecule," he says. "It doesn't have to be an approved drug. Anyone who tests their molecule could come up with something important."
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Biology
| 2,021 |
May 3, 2021
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https://www.sciencedaily.com/releases/2021/05/210503172841.htm
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Mutant corn gene boosts sugar in seeds, leaves, may lead to breeding better crop
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An abnormal build up of carbohydrates -- sugars and starches -- in the kernels and leaves of a mutant line of corn can be traced to one misregulated gene, and that discovery offers clues about how the plant deals with stress.
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That is the conclusion of Penn State researchers whose previous study discovered the Maize ufo1 gene responsible for creating the mutant corn line. They now are assessing its effects and potential for inclusion in breeding new lines of corn better able to thrive in a warming world. The finding of higher sugar levels in plant tissues in their latest study is just another aspect for plant geneticists to consider."This discovery has implications for food security and breeding new crop lines that can better deal with a changing climate -- with corn, there is still a lot to be done," said Surinder Chopra, professor of maize genetics in the College of Agricultural Sciences. "In fact, there is a great deal of genetic and phenotypic diversity in corn, and we can use that diversity and ask the question, 'How is the ufo1 gene distributed in the existing 10,000 germplasm lines?'"Can plant geneticists select for some of that diversity and incorporate the ufo1 gene to improve corn? That is the question Chopra is trying to answer, starting with this new study that found elevated sugar levels in seeds and leaves of the mutant corn line.What traits can be improved in corn with the ufo1 gene's help?"Certainly, stress tolerance, but also likely seed development, which has implications in seed yield as well as improved biomass," Chopra said. "And we would like to develop a better plant type that could grow in more dense culture, yet still be more productive. And finally, we need to look at resiliency and sustainability. Can we breed corn lines that get the same amount of yield with lower fertilizer inputs and need less water?"Chopra started research on the Maize ufo1 gene because of its association with an orange/red pigmentation in the mutant corn line. Celebrated maize geneticist Charles Burnham, at the University of Minnesota, identified this conspicuous ufo1 mutant circa 1960. Another well-known maize geneticist, Derek Styles, with the University of Victoria, Canada, a student of Burnham's, then chose the name, which stands for "unstable factor for orange."In 1997, Styles sent Chopra seeds for the mutant line. Since then, he introgressed its genes into an inbred line maintained by his research group at Penn State. In 2019, Chopra solved the genetic mystery behind ufo1.However, it turns out that the gene controls many plant characteristics beyond pigmentation. Still, ufo1 is just one gene, and it is not functioning alone in the corn genome, Chopra noted.There are more than 30,000 genes in the maize plant, so it is important to learn how ufo1 interacts with other genes before plant geneticists could use it in breeding a new type of crop, he added. "In order to go to the breeding aspect, we first need to learn how this gene actually functions," Chopra said. "We need to learn about how it partners with proteins, and learning about those protein interactions will be the goal of future research."But for now, this study revealed how accumulation of sugars in corn seed is modified in the presence or absence of the ufo1 gene, according to Debamalya Chatterjee, doctoral student in agronomy, who spearheaded the research."Down the road, we could use this knowledge of the ufo1 gene in breeding, to perform better crosses that make more resilient and more productive hybrids, where sugars and starches are in balance," he said.The researchers took a step in that direction today (May 3) when they published their findings in All plant materials analyzed in the study were grown during 2016-2020 summers at the Russell E. Larson Agricultural Research Center, Rock Springs, and in greenhouse and plant growth chamber facilities at Penn State's University Park campus. Inbreds and genetic stocks were obtained from the Maize Genetics Cooperation Stock Center managed by the U.S. Department of Agriculture's Agricultural Research Service.The National Science Foundation and an international fellowship from the Indian Council of Agricultural Research supported this work.
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Biology
| 2,021 |
May 3, 2021
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https://www.sciencedaily.com/releases/2021/05/210503151601.htm
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Study sequences genome of extinct date palms germinated from 2,000 year-old seeds
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Researchers from NYU Abu Dhabi's Center for Genomics and Systems Biology have successfully sequenced the genome of previously extinct date palm varieties that lived more than 2,000 years ago. They did so using date palm seeds that were recovered from archaeological sites in the southern Levant region and radiocarbon-dated from the 4th century BCE to the 2nd century CE. The seeds were germinated to yield viable, new plants. The researchers conducted whole genome sequencing of these germinated ancient samples and used this genome data to examine the genetics of these previously extinct Judean date palms.
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By examining the genome of a species (Phoenix dactylifera L.) that thrived centuries ago, Professor of Biology Michael D. Purugganan and his NYUAD colleagues, along with research partners in Israel, and France, were able to see how these plants evolved over a period of time. In this case, they observed that between the 4th century BCE and 2nd century CE, date palms in the eastern Mediterranean started to show increasing levels of genes from another species, Phoenix theophrasti, which today grows in Crete and some other Greek islands, as well as southwestern Turkey, as a result of hybridization between species. They conclude that the increasing level of genes from P. theophrasti over this period shows the increasing influence of the Roman Empire in the eastern Mediterranean.Their findings are reported in "We are fortunate that date palm seeds can live a long time -- in this case, more than 2,000 years -- and germinate with minimal DNA damage, in the dry environment of the region," said Purugganan. "This 'resurrection genomics' approach is a remarkably effective way to study the genetics and evolution of past and possibly extinct species like Judean date palms. By reviving biological material such as germinating ancient seeds from archaeological, paleontological sites, or historical collections, we can not only study the genomes of lost populations but also, in some instances, rediscover genes that may have gone extinct in modern varieties."
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Biology
| 2,021 |
May 3, 2021
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https://www.sciencedaily.com/releases/2021/05/210503144724.htm
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Human organ chips enable COVID-19 drug repurposing
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A Wyss Institute-led collaboration spanning four research labs and hundreds of miles has used the Institute's organ-on-a-chip (Organ Chip) technology to identify the antimalarial drug amodiaquine as a potent inhibitor of infection with SARS-CoV-2, the virus that causes COVID-19.
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The Organ Chip-based drug testing ecosystem established by the collaboration greatly streamlines the process of evaluating the safety and efficacy of existing drugs for new medical applications, and provides a proof-of-concept for the use of Organ Chips to rapidly repurpose existing drugs for new medical applications, including future pandemics. The research is reported in While many groups around the world have been testing existing drugs for efficacy against COVID-19 using cultured cells, it is well known that cells grown in a dish do not behave like the cells in a living human body, and many drugs that appear effective in lab studies do not work in patients. The Wyss team examined eight existing drugs, including hydroxychloroquine and chloroquine, that they and others had found were active against SARS-CoV-2 in conventional cell culture assays.When tested in their more sophisticated microfluidic Lung Airway Chip, which had been infected with a pseudotyped SARS-CoV-2 virus, they found that most of these drugs, including hydroxychloroquine and chloroquine, were not effective. However, another antimalarial drug, amodiaquine, was highly effective at preventing viral entry. These results were then validated in cultured cells and in a small animal model of COVID-19 using infectious SARS-CoV-2 virus. Amodiaquine is now in clinical trials for COVID-19 at multiple sites in Africa, where this drug is inexpensive and widely available."The speed with which this team assembled, pivoted to COVID-19, and produced clinically significant results is astonishing," said senior author and Wyss Institute Founding Director Don Ingber, M.D., Ph.D. "We started testing these compounds in February 2020, had data by March, and published a preprint in April. Thanks to the openness and collaboration that the pandemic has sparked within the scientific community, our lead drug is now being tested in humans. It's a powerful testament to Organ Chips' ability to accelerate preclinical testing."In the early months of the COVID-19 pandemic when little was known about the novel SARS-CoV-2 virus, efforts were made around the globe to identify existing drugs that could be repurposed to treat patients who were falling ill. While early data performed on cells grown in lab dishes seemed to suggest that the antimalarial drugs chloroquine and hydroxychloroquine could treat the disease, later studies showed that they aren't active against SARS-CoV-2 in animals or patients, and the quest for an effective oral therapeutic that can both treat and prevent COVID-19 continues.Fortunately, the Wyss Institute had a ready-made solution to that problem. In a move that today seems prescient, over three years ago the Defense Advanced Research Projects Agency (DARPA) and National Institutes of Health (NIH) awarded funding to Ingber's team to explore whether its human Organ Chip microfluidic culture technology, which faithfully mimics the function of human organs in vitro, could be used to confront potential biothreat challenges including pandemic respiratory viruses.Two years into the project, the team was making steady progress using its lung Airway Chip to study drugs that could be repurposed to treat influenza virus infections. Then, in January 2020, first authors Longlong Si, Ph.D. and Haiqing Bai, Ph.D. heard about cases of what was being called a novel viral pneumonia in China."That caught a lot of scientists' attention, because any new virus could become a global threat given how easily infections spread in today's era of widespread international travel. We closely followed the updates because we thought that our Airway Chip model could provide an important tool for studying this virus," said Si, a Wyss Technology Development Fellow and co-lead author. Once it became clear that people were falling ill due to the mysterious COVID-19 and not pneumonia, the team quickly shifted its focus to the novel SARS-CoV-2 virus.The human Airway Chip that the Wyss team developed for these studies is a microfluidic device about the size of a USB memory stick that contains two parallel channels separated by a porous membrane. Human lung airway cells are grown in one channel that is perfused with air, while human blood vessel cells are grown in the other channel, which is perfused with liquid culture medium to mimic blood flow. Cells grown in this device naturally differentiate into multiple airway-specific cell types in proportions that are similar to those in the human airway, and develop traits observed in living lungs such as cilia and the ability to produce and move mucus. Airway Chip cells also have higher levels of angiotensin-converting enzyme-2 (ACE2) receptor protein, which plays a central role in lung physiology and is used by SARS-CoV-2 to infect cells."Our biggest challenge in shifting our focus to SARS-CoV-2 was that we don't have lab facilities with the necessary infrastructure to safely study dangerous pathogens. To get around that problem, we designed a SARS-CoV-2 pseudovirus that expresses the SARS-CoV-2 spike protein, so that we could identify drugs that interfere with the spike protein's ability to bind to human lung cells' ACE2 receptors," said Bai, who is a Postdoctoral Fellow at the Wyss Institute and co-lead author. "A secondary goal was to demonstrate that these types of studies could be carried out by other Organ Chip researchers who similarly have this technology, but lack access to lab facilities required to study highly infectious viruses."Armed with the pseudovirus that allowed them to study SARS-CoV-2 infection, the team first perfused the Airway Chips' blood vessel channel with several approved drugs, including amodiaquine, toremifene, clomiphene, chloroquine, hydroxychloroquine, arbidol, verapamil, and amiodarone, all of which have exhibited activity against other related viruses in previous studies. However, in contrast to static culture studies, they were able to perfuse the drug through the channels of the chip using a clinically relevant dose to mimic how the drug would be distributed to tissues in our bodies. After 24 hours they introduced SARS-CoV-2 pseudovirus into the Airway Chips' air channel to mimic infection by airborne viruses, like that in a cough or sneeze.Only three of these drugs ? amodiaquine, toremifene, and clomiphene ? significantly prevented viral entry without producing cell damage in the Airway Chips. The most potent drug, amodiaquine, reduced infection by about 60%. The team also performed spectrometry measurements with the assistance of Steve Gygi, Ph.D.'s group at Harvard Medical School to assess how the drugs impacted the airway cells. These studies revealed that amodiaquine produced distinct and broader protein changes than the other antimalarial drugs.The researchers had a lead drug candidate.Despite the promise of amodiaquine, the team still needed to demonstrate that it worked against the real infectious SARS-CoV-2 virus. With the help of a new COVID-19-focused grant from DARPA, Ingber teamed up with Matthew Frieman, Ph.D. at the University of Maryland School of Medicin and Benjamin tenOever, Ph.D. at the Icahn School of Medicine at Mount Sinai, both of whom already had biosafety labs set up to study infectious pathogens.This collaboration created a drug discovery ecosystem that combines the human emulation capability of the Wyss Institute's Organ Chips with Frieman's and tenOever's expertise in the interactions between viruses and their host cells. The Frieman lab tested amodiaquine and its active metabolite, desethylamodiaquine, against native SARS-CoV-2 via high-throughput assays in cells in vitro, and confirmed that the drug inhibited viral infection.In parallel, the tenOever lab tested amodiaquine and hydroxychloroquine against native SARS-CoV-2 in a head-to-head comparison in a small animal COVID-19 model, and saw that prophylactic treatment with amodiaquine resulted in ~70% reduction in viral load upon exposure, while hydroxychloroquine was ineffective. They also saw that amodiaquine prevented the transmission of the virus from sick to healthy animals more than 90% of the time, and that it was also effective in reducing viral load when administered after introduction of the virus. Thus, their results suggest that amodiaquine could work in both treatment and prevention modes."Seeing how beautifully amodiaquine inhibited infection in the Airway Chip was extremely exciting," said Frieman. "And, the fact that it seems to work both before and after exposure to SARS-CoV-2 means that it could potentially be effective in a wide variety of settings.""This collaboration has allowed us to do things that we never would have had the resources to do otherwise, including recently setting up Organ Chips in our own lab so that we can now use them to study the interactions between infectious viruses and their hosts. While we're proud of what we've accomplished so far for COVID-19, we're also looking forward to studying additional virus-host dynamics using the Organ Chips in the hopes that we'll be able to prevent or address future pandemics," said tenOever, who is a Professor of Microbiology.A preprint of the amodiaquine results was published online on April 15, 2020, which generated buzz in the scientific community. It eventually caught the eye of Medicines for Malaria Venture, a leading product development partnership in antimalarial drug research. These results, along with studies from several other groups, contributed to amodiaquine's inclusion in a clinical trial in collaboration with the University of Witwatersrand in South Africa and Shin Poong Pharmaceutical in South Korea last fall. A few months later, the Drugs for Neglected Diseases Initiative (DNDi) added amodiaquine to the ANTICOV clinical trial for COVID-19, which spans 19 sites in over 13 different countries in Africa. Amodiaquine is oral, extremely inexpensive, and widely available in Africa. If proven effective in these clinical trials, it could provide a badly needed weapon against COVID-19 in low-resource nations where access to vaccines and expensive new therapeutics is limited.While the identification of amodiaquine is a major boon in fighting COVID-19, the team already has their sights set on future pandemics. In addition to SARS-CoV-2, their recent publication details their success in finding drugs that could protect against or treat several strains of influenza virus."Thanks to our experience using this drug development pipeline to validate amodiaquine for COVID-19, we are now applying what we learned to influenza and other pandemic-causing pathogens," said co-author Ken Carlson, Ph.D., a Lead Senior Staff Scientist who helps lead the Coronavirus Therapeutic Project Team at the Wyss Institute. "This process has given us confidence that Organ Chips are predictive of what we see in more complex living models of viral infections, and helped harness the creative cauldron of the Wyss Institute to consolidate and strengthen our therapeutic discovery engine."In addition to influenza, the team is now exploring drugs that could be used against the new SARS-CoV-2 mutant strains, to suppress the dangerous "cytokine storm" that leads to many hospitalizations, and to relieve the symptoms of COVID-19 "long haulers.""The pandemic has really gelled the Wyss Institute's Bioinspired Therapeutics development program, and linking up with the Frieman and tenOever labs has created a drug discovery and development pipeline that dramatically speeds up the whole process, quickly shepherding COVID-19 drugs through preclinical development to the point where they can be tested in humans. With Organ Chip technology in hand, we are now in a stronger position to confront future pandemics," said Ingber, who is also the Judah Folkman Professor of Vascular Biology at Harvard Medical School and Boston Children's Hospital, and Professor of Bioengineering at the Harvard John A. Paulson School of Engineering and Applied Sciences.Additional authors of the paper include Melissa Rodas, Wuji Cao, Crystal Oh, Mercy Soong, Atiq Nurani, Seong Min Kim, Danni Zhu, Girija Goyal, Rani Powers, and Roberto Plebiani from the Wyss Institute; former Wyss Institute members Rachelle Prantil-Baun, Kambez Benam, and Sarah Gilpin; Amanda Jiang from Boston Children's Hospital and Harvard Medical School; Rasmus Moller, Daisy Hoagland, Kohei Oishi, Shu Horiuchi, Skyler Uhl, Daniel Blanco-Melo, Tristan Jordan, Benjamin Nilsson-Payant, Ilona Golynker, and Justin Frere from the Icahn School of Medicine at Mount Sinai; James Logue, Robert Haupt, Marisa McGrath, and Stuart Weston from the University of Maryland School of Medicine; Tian Zhang and Steve Gygi from Harvard Medical School;This research was supported by the NIH (NCATS 1-UG3-HL-141797-01 and NCATS 1-UH3-HL- 141797-01), DARPA (W911NF-12-2-0036 and W911NF-16-C-0050), the Bill and Melinda Gates Foundation, the Marc Haas Foundation, and the Wyss Institute for Biologically Inspired Engineering at Harvard University.
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Biology
| 2,021 |
May 3, 2021
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https://www.sciencedaily.com/releases/2021/05/210503144721.htm
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Unraveling a mystery of dinoflagellate genomic architecture
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New work from a Stanford University-led team of researchers including Carnegie's Arthur Grossman and Tingting Xiang unravels a longstanding mystery about the relationship between form and function in the genetic material of a diverse group of algae called dinoflagellates.
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Their findings, published in Dinoflagellates include more than 2,000 species of marine and freshwater plankton, many of which are photosynthetic, and some of which also ingest other organisms for food. They play a wide variety of roles in various ecosystems, including extreme environments, and are predominantly known to humans as the cause of toxic "red tides" and as the source of most ocean bioluminescence.Some photosynthetic dinoflagellates are also crucial to the health of coral reefs. These algae are taken up by individual coral cells and form mutually beneficial relationships through which nutrients are exchanged. Ocean warming and pollution can cause this relationship between the alga and animal to break down, resulting in ghostly white "bleached" corals that are at risk of starvation, which could lead to the death of reef ecosystems."Like animals and plants, dinoflagellates are complex eukaryotic organisms and are evolutionarily interesting because their genetic material is packaged in a way that is unique among organisms with complex cellular architecture," said lead author Georgi Marinov of Stanford University.One defining characteristic of eukaryotes is that their DNA is housed inside a nucleus within each cell and is organized as separate units called chromosomes. Furthermore, in most eukaryotes, segments of DNA are wound around a spool-like complex of proteins called a nucleosome. This organization is thought to predate the common ancestor of all eukaryotes. It helps to condense the genetic material into a small space and control access to the DNA and how the genes encoded in it are activated to direct the cell's physiological functions."By contrast, even though dinoflagellates are eukaryotes, their genome is not packaged as nucleosomes, but rather appears to be permanently condensed and exist in a liquid crystal state," Grossman explained. "We still have so much to learn about how genome architecture influences genome function in all eukaryotes; so, dinoflagellate's exceptional 'tight' packaging of DNA may help us understand the similarities and differences in organizational principles among eukaryote genomes."To delve into this question, the research team -- which also included Stanford's Alexandro E. Trevino, Anshul Kundaje, and William J. Greenleaf -- used sophisticated technology to map the 3-D spatial relationships of the genetic material of the dinoflagellate Breviolum minutum."Our work revealed topological features in the Breviolum genome that differ from the various models of dinoflagellate genome organization that have been predicted since the 1960s," said Xiang.They found evidence of large self-interacting regions of DNA in the dinoflagellate genome called "topologically associating domains." The work suggests that this genomic architecture is induced by the process by which genes are transcribed into RNA; this RNA is subsequently translated into proteins that perform the cell's various activities.In fact, when transcription was inhibited, the architecture 'loosened up', indicating that the rigidly preserved topographical features are, indeed, a function of gene activity."There are many more questions raised by these results, which represent a big step forward in unraveling the mysteries of the dinoflagellate genome. They are also providing a new perspective on structure-function relationships inherent to chromosomes," Grossman concluded.
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Biology
| 2,021 |
May 3, 2021
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https://www.sciencedaily.com/releases/2021/05/210503135635.htm
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Microfossil found in Scottish Highlands could be 'missing link' in early animal evolution
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The billion-year-old fossil of an organism, exquisitely preserved in the Scottish Highlands, reveals features of multicellularity nearly 400 million years before the biological trait emerged in the first animals, according to a new report in the journal
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The discovery could be the "missing link" in the evolution of animals, according to the team, which included scientists from the U.S., United Kingdom, and Australia. The microfossil, discovered at Loch Torridon, contains two distinct cell types and could be the earliest example of complex multicellularity ever recorded, according to the researchers.The fossil offers new insight into the transition of single celled organisms to complex, multicellular animals. Modern single-celled holozoa include the most basal living animals and the fossil discovered shows an organism which lies somewhere between single cell and multicellular animals, or metazoa."Our findings show that the genetic underpinnings of cell-to-cell cohesion and segregation -- the ability for different cells to sort themselves into separate regions within a multicellular mass -- existed in unicellular organisms a billion years ago, some 400 million years before such capabilities were incorporated into the first animals," said Strother, a research professor in the Department of Earth and Environmental Sciences at Boston College.The fossil's discovery in an inland lake shifts the focus on the first forms of early life from the ocean to freshwater.Animals, or etazoa, are one of only five groups of organisms that have evolved complex multicellularity -- organisms that grow from a single cell that develops into a myriad of different cells and tissues. Animals probably evolved from unicellular ancestors that went through multicellular stages during their life cycles, said Strother, an expert in paleobotany and palynology, the study of fossil spores and pollen. Land plants, too, achieved complex multicellularity when they evolved from simpler algal ancestors some time during the early Paleozoic from about 500 to 400 million years ago.."We describe here a new fossil that is similar to living unicellular relatives of animals, belonging to the group Ichthyosporea," said Strother. "Our fossil shows life-cycle stages with two different kinds of cells, which could be the first step toward the evolution of complex multicellularity in the evolutionary lineage leading to the Metazoa."The study was based on populations of cells preserved in the mineral phosphate that were collected from billion-year-old lake deposits found in the northwest Scottish Highlands, Strother said. Samples are prepared in rock thin sections which allow microfossils to be seen under the light microscope or with a focused ion beam microscope.The microfossils were discovered as part of an ongoing project to describe life living in freshwater lakes one billion years ago, using samples collected in Scotland and Michigan by Strother beginning in 2008, with support from NASA and the National Geographic Society, and now the Natural Environment Research Council in the UK.The new fossil has been described and formally named Bicellum brasieri in the new report.Strother said the discovery has the potential to change the way scientists look at the earliest forms of life on Earth."Our study of life in billion-year-old lakes is challenged by our ability to determine which kinds of organisms are represented in these deposits," he said. "Previously we have assumed that most of what we see in these deposits are various kinds of extinct algae, but the morphological features of Bicellum really are more like those of modern-day unicellular relatives of animals. This is causing us to broaden our approach to reconstructing the diversity and ecology of life on Earth one billion years ago."The discovery will allow researchers to expand upon a more thorough reconstruction of the life-cycle of Bicellum, Strother said."Armed with comparative morphology with modern day Ichthyosporeans, we may be able to recognize additional morphogenic stages and determine how a single generative cell divides to become a multicellular cell mass," he said.
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Biology
| 2,021 |
May 3, 2021
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https://www.sciencedaily.com/releases/2021/05/210503104813.htm
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An animal able to regenerate all of its organs even when it is dissected into three parts
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An extraordinary discovery in the Gulf of Eilat: Researchers from Tel Aviv University have discovered a species of ascidian, a marine animal commonly found in the Gulf of Eilat, capable of regenerating all of its organs - even if it is dissected into three fragments. The study was led by Prof. Noa Shenkar, Prof. Dorothee Huchon-Pupko, and Tal Gordon of Tel Aviv University's School of Zoology at the George S. Wise Faculty of Life Sciences and the Steinhardt Museum of Natural History. The findings of this surprising discovery were published in the leading journal
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"It is an astounding discovery, as this is an animal that belongs to the Phylum Chordata - animals with a dorsal cord - which also includes us humans," explains Prof. Noa Shenkar. "The ability to regenerate organs is common in the animal kingdom, and even among chordates you can find animals that regenerate organs, like the gecko who is able to grow a new tail. But not entire body systems. Here we found a chordate that can regenerate all of its organs even if it is separated into three pieces, with each piece knowing exactly how to regain functioning of all its missing body systems within a short period of time."There are hundreds of species of ascidians, and they are found in all of the world's oceans and seas. Anyone who has ever opened their eyes underwater has seen ascidians without knowing it, as they often camouflage themselves as lumps on rocks and are therefore difficult to discern. The animal that is the subject of this new study is an ascidian from the species "By all accounts, the ascidian is a simple organism, with two openings in its body: an entry and an exit," says Tal Gordon, whose doctoral dissertation included this new research. "Inside the body there is a central organ that resembles a pasta strainer. The ascidian sucks in water through the body's entry point, the strainer filters the food particles that remain in the body, and the clean water exits through the exit point. Among invertebrates, they are considered to be the closest to humans from an evolutionary point of view."Ascidians are famous for their regenerative ability, but until now these abilities have been identified mainly in asexual reproduction. Never before has such a high regenerative capacity been detected in a chordate animal that reproduces only by sexual reproduction."There are species of ascidians that perform simple regeneration in order to reproduce," Gordon says. "These are species with a colonial lifestyle, with many identical individuals connected to one another. They replicate themselves in order to grow. In contrast, the ascidian from Eilat, Prof. Shenkar concludes: "Since the dawn of humanity, humans have been fascinated by the ability to regenerate damaged or missing organs. Regeneration is a wonderful ability that we have, to a very limited extent, and we would like to understand how it works in order to try and apply it within our own bodies. Anyone snorkeling in the Gulf of Eilat can find this intriguing ascidian, who may be able to help us comprehend processes of tissue renewal that can help the human race."
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Biology
| 2,021 |
May 3, 2021
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https://www.sciencedaily.com/releases/2021/05/210503100007.htm
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Tailor-made therapy of multi-resistant tuberculosis
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Globally, tuberculosis is the most common bacterial infectious disease leading to death. The pathogen causing tuberculosis, Mycobacterium tuberculosis, has a number of peculiarities. One is that it is growing very slowly. While other typical pathogens, such as pneumococcal and pseudomonads, can already be identified by their growth in the microbiological laboratory in the first 72 hours, several weeks usually pass before tuberculosis bacteria grow in the lab. Thus it often takes one to two months before the efficacy of individual medicines can be tested.
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However, these efficacy tests are essential for the effective treatment of multidrug-resistant tuberculosis (MDR-TB), which is becoming increasingly common. In these cases, the pathogen has become resistant, i.e. insensitive, to the best tuberculosis drugs, rifampicin and isoniazid. This is due to changes in the genome, so-called mutations, which almost always occur at the same points in the genome. Treatment of MDR-TB is protracted, costly and frequently associated with side effects.For the selection of antibiotics in a combination therapy, doctors have so far depended on the results of the drug test after cultivation. "Currently, 15 drugs are available for second-line therapy, of which at least four are used in combination," explains Prof. Christoph Lange, coordinator of the clinical study at the Research Center Borstel.In order to accelerate the choice of the most effective antibiotics, DZIF scientists at the Research Center Borstel, led by Prof. Stefan Niemann, have created a catalogue of mutations in the genetic material of tuberculosis bacteria that permits prediction of antibiotic resistances of the bacteria against all drugs. Unlike many other bacteria, the genetic material of the tuberculosis bacteria hardly changes over time. The genome of tuberculosis bacteria carries roughly 4.4 millions of building blocks (base pairs) that store the information for about 4,000 genes.Hans-Peter Grobbel, medical student and predoctoral DZIF fellow in Christoph Lange's team, supported by his fellow student Niklas Köhler, Professor Matthias Merker, Dr Sönke Andres and Dr Harald Hoffmans, has examined the results of antibiotic resistance predictions through overall genome analyses. Using tuberculosis bacteria from70 patients with MDR-TB treated at the Borstel Department of Medicine, researchers compared the molecular prediction of antibiotic resistance with actual cultural test results. They were contributed by Prof. Florian Maurer, Head of the National Reference Laboratory for Tuberculosis Bacteria in Borstel. The scientists also examined whether reliable combinations of drugs for the treatment of MDR-TB could be compiled based on the prediction of the bacteria´s genetic material."Ninety-nine per cent of all drugs in combination therapies that we have assembled based on the results of molecular predictions from the genetic material of tuberculosis bacteria are also effective according to traditional microbiological antibiotic resistance testing," Grobbel explains. By now, the molecular methods are both cheap and fast. Ideally, patients can already receive tailored MDR-TB treatment in the first week of their tuberculosis diagnosis.
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Biology
| 2,021 |
May 3, 2021
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https://www.sciencedaily.com/releases/2021/05/210503100002.htm
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How plants find their symbiotic partners
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What would it be like to produce fertilizer in your own basement? Leguminous plants, like peas, beans, and various species of clover, obtain the organic nitrogen they need for their growth from symbiotic soil bacteria via specialized structures in their roots. A team led by the cell biologist Prof. Dr. Thomas Ott from the University of Freiburg's Faculty of Biology has now detected a factor in the root cells that the plants need for the initial contact with these so-called root-associated bacteria, which live in the soil. They discovered a protein found only in legumes called symbiotic formin 1 (SYFO1) and demonstrated the essential role it plays in symbiosis. Together with the molecular biologist Prof. Dr. Robert Grosse University of Freiburg's Faculty of Medicine and the evolutionary biologist Dr. Pierre-Marc Delaux from the Laboratoire de Recherche en Sciences Végétales (LRSV) in Toulouse/France, the team published their results in the journal
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When a root nodule bacterium encounters the roots of a leguminous plant in the soil, the SYFO1 protein causes the tiny hairs of the root to change the direction of their growth. They thus wrap themselves around the potential symbiotic partner. Thanks to these bacterial helpers, legumes do not need any nitrogenous fertilizer, in contrast to other plants. "If we understood precisely how the symbiosis comes into being, we could give crop plants back this special property they have lost in the course of evolution," says Ott. Both he and Grosse are members of the Cluster of Excellence CIBSS -- Centre for Integrative Biological Signalling Studies. Ott's research at CIBSS involves studying the spatial organization of the signaling paths that enable the symbiotic relationship with symbiotic bacteria in the first place. Grosse, on the other hand, focuses in his work in Freiburg on the cytoskeleton of animal cells. "In our collaboration, which was made possible by CIBSS, we were able to contribute our expertise in different areas of specialization in the best possible way," says Ott.The team demonstrated in the legume Medicago truncatula (barrel medic) that the root hairs of plants in which the gene for SYFO1 has been switched off are practically no longer capable of wrapping themselves around the bacteria. In further studies, the researchers discovered that the protein binds to actin, a component of the cytoskeleton, and at the same time to the cell wall outside the cells, thus changing the direction of its growth: Instead of growing straight, the tiny hairs now change their direction and form a loop around the bacterium."SYFO1 constitutes a special innovative step in the evolution of the plants," explains Ott. "While formin proteins are present in many forms in cells and interact with actin, this special type only responds to symbiotic signals from the bacteria."
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Biology
| 2,021 |
May 3, 2021
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https://www.sciencedaily.com/releases/2021/05/210503090938.htm
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Applying UV light to common disinfectants makes them safer to use, study finds
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Over 400 common disinfectants currently in use could be made safer for people and the environment and could better fight the COVID-19 virus with the simple application of UVC light, a new study from the University of Waterloo shows.
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Benzalkonium chloride (BAK) is the most common active ingredient in many disinfectants regularly used in hospitals, households, and food processing plants to protect against a wide range of viruses and bacteria -- including all strains of SARS-CoV-2, the coronavirus that causes COVID-19 -- but its toxicity means that it can't be used in high concentrations. It also means that products containing BAK are harmful to humans and the environment.Researchers at Waterloo discovered that the chemical's toxicity could be fully neutralized using ultraviolet light (UVC) when tested on cultured human corneal cells."Our results show that a disinfecting procedure using BAK followed by UVC radiation can minimize the harmful effect of BAK residues on humans and the environment," said Dr. David McCanna of Waterloo's Department of Optometry & Vision Science. "Such a procedure also has a great potential to maximize the disinfection efficacy by utilizing two different antimicrobial mechanisms."As the pandemic continues, our findings are especially important as it provides another method to make our hospitals, food, homes, and the environment safer."While an important ingredient for a disinfectant's efficacy, BAK is a severe human skin and eye irritant. The chemical's high toxicity limits the ability to use products with a high concentration of BAK to better protect against harmful viruses and bacteria. High levels of BAK residue are also harmful to the environment, proving especially toxic to fish, aquatic invertebrates, and birds.After exposing a BAK solution to germicidal ultraviolet-C lamps, they applied the solution to cultured human corneal cells for five minutes and analyzed for cell metabolic activity and viability. The BAK solutions were completely neutralized by UVC as the solutions no longer harmed the cultured human corneal epithelial cells."With concerns about the spread of COVID-19, people are utilizing products with BAK as an active ingredient more than ever," said Waterloo alumnus and lead author Dr. Manlong Xu, who is currently a clinical research fellow in the University of Alberta's Department of Ophthalmology and Visual Science."For many industries, there is the demand to improve the efficacy of standard disinfection procedures, while also keeping in mind any potential negative impact on the environment."The study, Neutralization of the eye and skin irritant benzalkonium chloride using UVC radiation, authored by Waterloo's Faculty of Science's Dr. McCanna and Dr. Jacob Sivak and Dr. Xu was recently published in the journal
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Biology
| 2,021 |
May 3, 2021
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https://www.sciencedaily.com/releases/2021/05/210503093525.htm
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Natural immunity to malaria provides clues to potential therapies
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WEHI researchers have identified how natural human antibodies can block malaria parasites from entering red blood cells, potentially indicating how new protective therapies could be developed against this globally significant disease.
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The research provides greater insight into how antibodies block the entry of Plasmodium vivax malaria parasites into young red blood cells called reticulocytes. It builds on an earlier discovery that the The research, led by Associate Professor Wai-Hong Tham and PhD student Li-Jin Chan from WEHI, alongside Professor Christopher King from Case Western University, US, was published in Nature Communications.Plasmodium vivax is the most widespread malaria parasite in the world, and the predominant cause of malaria in the vast majority of countries outside Africa. It is also the main parasite responsible for recurrent malaria infections.The malaria parasite is a complex single-celled organism, with diverse proteins that help it to invade red blood cells, reproduce and spread. Adhesins on the surface of the parasite are key-like proteins that 'unlock' cells, allowing the parasite to enter.Previous research studies in Papua New Guinea, Thailand and Brazil showed antibodies against "We wanted to understand how these human antibodies in natural infection block the parasite from getting in. By extracting and examining antibodies from people who have had This discovery opens the door to potentially preventing not only "Although this was a vivax study, we believe the implications are that a broadly neutralising antibody could be created to target both WEHI Professor Ivo Mueller said beyond understanding how antibodies can block infection, there was also a crucial need to understand the development of immunity and how this could be used to detect "We are currently using this information to develop diagnostic tests that will be used in the field to identify and treat people with hidden vivax infection in their livers and spleens. This is a key step towards eliminating malaria, by preventing silently infected people reinfecting their communities," he said.This work was made possible with funding from the National Health and Medical Research Council, the European Research Council and the Victorian Government.
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Biology
| 2,021 |
April 30, 2021
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https://www.sciencedaily.com/releases/2021/04/210430144731.htm
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Piecing together the LanCL puzzle
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Researchers from the Carl R. Woese Institute for Genomic Biology in collaboration with scientists at Oxford University have published a paper in
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Bacteria contain enzymes called LanC that are capable of producing small proteins called lanthipeptides, which are characterized by the addition of a thiol group to a modified serine or threonine amino acid. Similar proteins -- called LanC-like or LanCL -- have been found in different eukaryotic cells for decades, but their function was unknown."LanCLs are found in nearly all higher organisms, including humans. Although scientists have worked on these proteins for over 20 years, we didn't know their function. We had several hypotheses, which we kept ruling out based on our experiments," said Wilfred van der Donk (MMG), a professor of chemistry and investigator of the Howard Hughes Medical Institute.The first breakthrough came in 2015, when the Nair lab in the Department of Biochemistry solved the crystal structure of a LanC-containing protein in bacteria. The protein was bound to another enzyme called a kinase, which modifies proteins by adding a phosphate group. Inspired by this discovery, the researchers tested whether LanCL proteins were also binding to kinases in eukaryotic cells. "We saw that they were able to bind to many kinases, including AKT and mTOR, and all of a sudden the pieces of the puzzle started forming a picture," van der Donk said.The next piece fell into place in collaboration with Benjamin Davis, a professor of chemistry at the University of Oxford. The Davis group showed that eliminating a particular phosphate group in kinases causes them to become activated. Scientists had assumed that such processed proteins would be inactive. Together, the Illinois and Oxford groups were able to show that LanCL adds glutathione to kinases with eliminated phosphate groups, after which the kinases became deactivated. "We realized that when the LanCL proteins are absent, the cell has a big problem because there are active proteins floating around that need to be turned off," van der Donk said.The importance of these proteins became evident in mice that lacked them. "A third of the mice that lack these enzymes die when they are between four to six months old. They die suddenly without getting sick and we still don't understand why," said Jie Chen (GNDP), a professor of cell and developmental biology.The researchers are interested in understanding the role of these proteins and making a complete list of all the possible targets of LanCLs. "When you have abnormal kinases, it can cause all kinds of problems, including cancer. LanCL proteins eliminate these damaged kinases and it is possible that they also affect other proteins that we are not aware of. We need to connect their cellular functions to the results we saw in the mice," Chen said."This study is just the tip of the iceberg. Since these proteins are found everywhere, you can also imagine their effects in feedstock and the future of farming," said Satish Nair (MME/MMG), Head of the Department of Biochemistry."This study was possible because of the persistence of our graduate students. Most of us would have given up long ago because the studies were initially going nowhere," Nair said. "It also shows the importance of exploratory research, where you're essentially just looking around. Although it is risky, it is great to see that there are rewards for students who stick it out," van der Donk said.
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Biology
| 2,021 |
April 30, 2021
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https://www.sciencedaily.com/releases/2021/04/210430120411.htm
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Move over CRISPR, the Retrons are coming
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Researchers have created a new gene editing tool called Retron Library Recombineering (RLR) that can generate up to millions of mutations simultaneously, and 'barcodes' mutant bacterial cells so that the entire pool can be screened at once. It can be used in contexts where CRISPR is toxic or not feasible, and results in better editing rates.
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While the CRISPR-Cas9 gene editing system has become the poster child for innovation in synthetic biology, it has some major limitations. CRISPR-Cas9 can be programmed to find and cut specific pieces of DNA, but editing the DNA to create desired mutations requires tricking the cell into using a new piece of DNA to repair the break. This bait-and-switch can be complicated to orchestrate, and can even be toxic to cells because Cas9 often cuts unintended, off-target sites as well.Alternative gene editing techniques called recombineering instead perform this bait-and-switch by introducing an alternate piece of DNA while a cell is replicating its genome, efficiently creating genetic mutations without breaking DNA. These methods are simple enough that they can be used in many cells at once to create complex pools of mutations for researchers to study. Figuring out what the effects of those mutations are, however, requires that each mutant be isolated, sequenced, and characterized: a time-consuming and impractical task.Researchers at the Wyss Institute for Biologically Inspired Engineering at Harvard University and Harvard Medical School (HMS) have created a new gene editing tool called Retron Library Recombineering (RLR) that makes this task easier. RLR generates up to millions of mutations simultaneously, and "barcodes" mutant cells so that the entire pool can be screened at once, enabling massive amounts of data to be easily generated and analyzed. The achievement, which has been accomplished in bacterial cells, is described in a recent paper in "RLR enabled us to do something that's impossible to do with CRISPR: we randomly chopped up a bacterial genome, turned those genetic fragments into single-stranded DNA in situ, and used them to screen millions of sequences simultaneously," said co-first author Max Schubert, Ph.D., a postdoc in the lab of Wyss Core Faculty member George Church, Ph.D. "RLR is a simpler, more flexible gene editing tool that can be used for highly multiplexed experiments, which eliminates the toxicity often observed with CRISPR and improves researchers' ability to explore mutations at the genome level."Retrons are segments of bacterial DNA that undergo reverse transcription to produce fragments of single-stranded DNA (ssDNA). Retrons' existence has been known for decades, but the function of the ssDNA they produce flummoxed scientists from the 1980s until June 2020, when a team finally figured out that retron ssDNA detects whether a virus has infected the cell, forming part of the bacterial immune system.While retrons were originally seen as simply a mysterious quirk of bacteria, researchers have become more interested in them over the last few years because they, like CRISPR, could be used for precise and flexible gene editing in bacteria, yeast, and even human cells."For a long time, CRISPR was just considered a weird thing that bacteria did, and figuring out how to harness it for genome engineering changed the world. Retrons are another bacterial innovation that might also provide some important advances," said Schubert. His interest in retrons was piqued several years ago because of their ability to produce ssDNA in bacteria -- an attractive feature for use in a gene editing process called oligonucleotide recombineering.Recombination-based gene editing techniques require integrating ssDNA containing a desired mutation into an organism's DNA, which can be done in one of two ways. Double-stranded DNA can be physically cut (with CRISPR-Cas9, for example) to induce the cell to incorporate the mutant sequence into its genome during the repair process, or the mutant DNA strand and a single-stranded annealing protein (SSAP) can be introduced into a cell that is replicating so that the SSAP incorporates the mutant strand into the daughter cells' DNA."We figured that retrons should give us the ability to produce ssDNA within the cells we want to edit rather than trying to force them into the cell from the outside, and without damaging the native DNA, which were both very compelling qualities," said co-first author Daniel Goodman, Ph.D., a former Graduate Research Fellow at the Wyss Institute who is now a Jane Coffin Childs Postdoctoral Fellow at UCSF.Another attraction of retrons is that their sequences themselves can serve as "barcodes" that identify which individuals within a pool of bacteria have received each retron sequence, enabling dramatically faster, pooled screens of precisely-created mutant strains.To see if they could actually use retrons to achieve efficient recombineering with retrons, Schubert and his colleagues first created circular plasmids of bacterial DNA that contained antibiotic resistance genes placed within retron sequences, as well as an SSAP gene to enable integration of the retron sequence into the bacterial genome. They inserted these retron plasmids into E. coli bacteria to see if the genes were successfully integrated into their genomes after 20 generations of cell replication. Initially, less than 0.1% of E. coli bearing the retron recombineering system incorporated the desired mutation.To improve this disappointing initial performance, the team made several genetic tweaks to the bacteria. First, they inactivated the cells' natural mismatch repair machinery, which corrects DNA replication errors and could therefore be "fixing" the desired mutations before they were able to be passed on to the next generation. They also inactivated two bacterial genes that code for exonucleases -- enzymes that destroy free-floating ssDNA. These changes dramatically increased the proportion of bacteria that incorporated the retron sequence, to more than 90% of the population.Now that they were confident that their retron ssDNA was incorporated into their bacteria's genomes, the team tested whether they could use the retrons as a genetic sequencing "shortcut," enabling many experiments to be performed in a mixture. Because each plasmid had its own unique retron sequence that can function as a "name tag," they reasoned that they should be able to sequence the much shorter retron rather than the whole bacterial genome to determine which mutation the cells had received.First, the team tested whether RLR could detect known antibiotic resistance mutations in E coli. They found that it could -- retron sequences containing these mutations were present in much greater proportions in their sequencing data compared with other mutations. The team also determined that RLR was sensitive and precise enough to measure small differences in resistance that result from very similar mutations. Crucially, gathering these data by sequencing barcodes from the entire pool of bacteria rather than isolating and sequencing individual mutants, dramatically speeds up the process.Then, the researchers took RLR one step further to see if it could be used on randomly-fragmented DNA, and find out how many retrons they could use at once. They chopped up the genome of a strain of E. coli highly resistant to another antibiotic, and used those fragments to build a library of tens of millions of genetic sequences contained within retron sequences in plasmids. "The simplicity of RLR really shone in this experiment, because it allowed us to build a much bigger library than what we can currently use with CRISPR, in which we have to synthesize both a guide and a donor DNA sequence to induce each mutation," said Schubert.This library was then introduced into the RLR-optimized E coli strain for analysis. Once again, the researchers found that retrons conferring antibiotic resistance could be easily identified by the fact that they were enriched relative to others when the pool of bacteria was sequenced."Being able to analyze pooled, barcoded mutant libraries with RLR enables millions of experiments to be performed simultaneously, allowing us to observe the effects of mutations across the genome, as well as how those mutations might interact with each other," said senior author George Church, who leads the Wyss Institute's Synthetic Biology Focus Area and is also a Professor of Genetics at HMS. "This work helps establish a road map toward using RLR in other genetic systems, which opens up many exciting possibilities for future genetic research."Another feature that distinguishes RLR from CRISPR is that the proportion of bacteria that successfully integrate a desired mutation into their genome increases over time as the bacteria replicate, whereas CRISPR's "one shot" method tends to either succeed or fail on the first try. RLR could potentially be combined with CRISPR to improve its editing performance, or could be used as an alternative in the many systems in which CRISPR is toxic.More work remains to be done on RLR to improve and standardize editing rate, but excitement is growing about this new tool. RLR's simple, streamlined nature could enable the study of how multiple mutations interact with each other, and the generation of a large number of data points that could enable the use of machine learning to predict further mutational effects."This new synthetic biology tool brings genome engineering to an even higher levels of throughput, which will undoubtedly lead to new, exciting, and unexpected innovations," said Don Ingber, M.D., Ph.D., the Wyss Institute's Founding Director. Ingber is also the Judah Folkman Professor of Vascular Biology at HMS and Boston Children's Hospital, and Professor of Bioengineering at the Harvard John A. Paulson School of Engineering and Applied Sciences.Additional authors of the paper include Timothy Wannier from HMS, Divjot Kaur from the University of Warwick, Fahim Farzadfard and Timothy Lu from the Massachusetts Institute of Technology, and Seth Shipman from the Gladstone Institute of Data Science and Biotechnology.This research was supported by the United States Department of Energy (DE-FG02-02ER63445) and by the National Defense Science and Engineering Graduate Fellowship.
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Biology
| 2,021 |
April 30, 2021
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https://www.sciencedaily.com/releases/2021/04/210430120357.htm
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Important factor in the development of dendritic cells identified
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The human immune system comprises functionally specialised cellular defence mechanisms that protect the body against disease. These include the dendritic cells. Their main function is to present antigens to other immune cells, especially T cells, thereby activating a primary immune response. Dendritic cells are divided into Type 1 (DC1) and Type 2 (DC2) dendritic cells. Each type fulfils different functions: DC1 provide an immune response to bacteria and viruses, DC2 protect against fungal or parasitic infections. In a recent study conducted at MedUni Vienna's Institute of Cancer Research, researchers found that a particular group of proteins plays a major role in the development of Type 1 dendritic cells. This could open up new therapeutic options in the defence against viruses or bacteria but also for cancer immunity.
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Dendritic cells are formed from multipotent progenitor cells in the bone marrow. However, it was hitherto unclear which proteins are responsible for this transition from stem cells to differentiated cells. The study, which has now been published in In order to analyse the role of these proteins, the c-Jun- and/or JunB gene was deleted in dendritic cells. "This showed that c-Jun and JunB are jointly, but not individually, essential for DC1 development," says second study author, Barbara Drobits from the Institute of Cancer Research and CCC. The mechanism in detail: working in a never previously described synergy, the c-Jun/JunB transcription factor pair together controls the development of DC1. "An expression analysis of DC1 lacking c-Jun/JunB, showed changes in the cellular identity, and a shift towards DC2." At the same time, the immunological functions of DC1 were greatly reduced when c-Jun/JunB were lacking. Differences were also found in an infection model. In the animal model, deactivation of c-Jun/JunB protected against infection with the bacterium Listeria monocytogenes."The results describe a previously unknown function of c-Jun/JunB in the development of dendritic cells. It has already been shown in previous studies that another member of the AP-1 family known as Batf3 is necessary for DC1 development, in that it regulates the expression of the transcription factor IRF8. However, it was not clear with which AP-1 protein Batf3 interacts to perform this function. Our data now provide this "missing link," in that they point to c-Jun/JunB as being Batf3's tango partner," summarise the study authors.DC1 are essential for defending against bacteria and viruses as well as for immunity to cancers -- a better understanding of the underlying biology could therefore provide new, promising therapeutic approaches for future clinical application.
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Biology
| 2,021 |
April 30, 2021
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https://www.sciencedaily.com/releases/2021/04/210430120346.htm
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Shortage of DNA building blocks in the cell releases mitochondrial DNA
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Mitochondria are the energy suppliers of our body cells. These tiny cell components have their own genetic material, which triggers an inflammatory response when released into the interior of the cell. The reasons for the release are not yet known, but some cardiac and neurodegenerative diseases as well as the ageing process are linked to the mitochondrial genome. Researchers at the Max Planck Institute for Biology of Ageing and the CECAD Cluster of Excellence in Ageing research have investigated the reasons for the release of mitochondrial genetic material and found a direct link to cellular metabolism: when the cell's DNA building blocks are in short supply, mitochondria release their genetic material and trigger inflammation. The researchers hope to find new therapeutic approaches by influencing this metabolic pathway.
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Our body needs energy -- for every metabolic process, every movement and for breathing. This energy is produced in tiny components of our body cells, the so-called mitochondria. Unlike other cell components, mitochondria have their own genetic material, mitochondrial DNA. However, in certain situations, mitochondria release their DNA into the interior of the cell, causing a reaction from the cell's own immune system and being associated with various diseases as well as the ageing process. The reasons for the release of mitochondrial DNA are not yet known.To answer the question of when mitochondria release their DNA, researchers at the Max Planck Institute for Biology of Ageing have focused on the mitochondrial protein YME1L, which owes its name to yeast mutants that release their mitochondrial DNA -- yeast mitochondrial escape 1. "In cells lacking YME1L, we observed the release of mitochondrial DNA into the cell interior and a related immune response in the cells," said Thomas MacVicar, one of the study's two first authors. Closer examination revealed a direct link to the building blocks of DNA. "If the cells lack YME1L, there is a deficiency of DNA building blocks inside the cell," Thomas MacVicar describes. "This deficiency triggers the release of mitochondrial DNA, which in turn causes an inflammatory response in the cell: the cell stimulates similar inflammatory reactions as it does during a bacterial or viral infection. If we add DNA building blocks to the cells from the outside, that also stops the inflammation."The discovered link between the cellular inflammatory response and the metabolism of DNA building blocks could have far-reaching consequences, explains Thomas MacVicar: "Some viral inhibitors stop the production of certain DNA building blocks, thereby triggering an inflammatory response. The release of mitochondrial DNA could be a crucial factor in this, contributing to the effect of these inhibitors." Several ageing-associated inflammatory diseases, including cardiac and neurodegenerative diseases, as well as obesity and cancer, are linked to mitochondrial DNA. The authors hope that modulating the metabolism of DNA building blocks will offer new therapeutic opportunities in such diseases.
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Biology
| 2,021 |
April 30, 2021
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https://www.sciencedaily.com/releases/2021/04/210430093215.htm
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Diverse spectrum of neurons that govern movement
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In a mouse study, National Institutes of Health researchers have identified and mapped a diverse spectrum of motor neurons along the spinal cord. These neurons, which send and receive messages throughout the body, include a subset that is susceptible to neurodegenerative diseases. Created with a genetic sequencing technique, the atlas reveals 21 subtypes of neurons in discrete areas throughout the spinal cord and offers insight into how these neurons control movement, how they contribute to the functioning of organ systems and why some are disproportionately affected in neurodegenerative diseases.
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The study was led by Claire Le Pichon, Ph.D., head of the Unit on the Development of Neurodegeneration at NIH's Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD). It appears in Spinal cord neurons are responsible for all types of movement in the body, ranging from voluntary movements like walking to the involuntary constriction and relaxation of the stomach as it processes its contents. Traditionally, scientists categorize these neurons into three main types: skeletal motor neurons, visceral motor neurons and interneurons. Previous research suggests there are additional subtypes within these three categories and that some of these subtypes may be more vulnerable to neurodegenerative diseases than others. For example, diseases like spinal muscular atrophy and amyotrophic lateral sclerosis, or ALS, affect only certain types of skeletal muscle neurons.In the current study, the team used a technique called single nucleus RNA sequencing to identify 21 subtypes of spinal cord neurons in mice. The findings reveal highly distinct subtypes, especially among motor neurons that control the glands and internal organs. The team also discovered that visceral motor neurons extend higher up along the spinal column than previously known. The authors believe these motor neurons may be newly discovered subtypes with unknown functions.
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Biology
| 2,021 |
April 30, 2021
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https://www.sciencedaily.com/releases/2021/04/210430120414.htm
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New view of species interactions offers clues to preserve threatened ecosystems
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As the health of ecosystems in regions around the globe declines due to a variety of rising threats, scientists continue to seek clues to help prevent future collapses.
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A new analysis by scientists from around the world, led by a researcher at the University of California San Diego, is furthering science's understanding of species interactions and how diversity contributes to the preservation of ecosystem health.A coalition of 49 researchers examined a deep well of data describing tree species in forests located across a broad range of countries, ecosystems and latitudes. Information about the 16 forest diversity plots in Panama, China, Sri Lanka, Puerto Rico and other locations -- many in remote, inaccessible areas -- had been collected by hundreds of scientists and students over decades.Lead researcher Christopher Wills, an evolutionary biologist and professor emeritus in the UC San Diego Division of Biological Sciences, says the new study addresses large questions about these complex ecosystems -- made up of trees, animals, insects and even bacteria and viruses -- and how such stunning diversity is maintained to support the health of the forest.The new analysis, believed to be the most detailed study of such an enormous set of ecological data, is published in the journal "Observational and experimental evidence shows that all ecosystems are characterized by strong interactions between and among their many species. These webs of interactions can be important contributors to the preservation of ecosystem diversity," said Wills.The authors note, however, that many of these interactions -- including those involving microscopic pathogens and the chemical defenses mounted by their prey -- are not easy to identify and analyze in ecosystems that feature tens to hundreds of millions of inhabitants.The researchers employed a detailed computational tool to extract hidden details from the forest census data. Their new "equal-area-annulus" method identifies pairs and groups of tree species that show unusually high or low levels of between-species interactions affecting their recruitment, mortality and growth. The authors found, unexpectedly, that closely-related pairs of tree species in a forest often interact weakly with each other, while distantly-related pairs can often interact with surprising strength. Such new information enables the design of further fieldwork and experiments to identify the many other species of organisms that have the potential to influence these interactions. These studies will in turn pave a path to understanding the roles of these webs of interactions in ecosystem stability.Most of the thousands of significant interactions that the new analysis revealed were of types that give advantages to the tree species if they are rare. The advantages disappear, however, when those species become common. Some well-studied examples of such disappearing advantages involve diseases of certain species of tree. These specialized diseases are less likely to spread when their host trees are rare, and more likely to spread when the hosts are plentiful. Such interaction patterns can help to maintain many different host tree species simultaneously in an ecosystem."We explored how our method can be used to identify the between-species interactions that play the largest roles in the maintenance of ecosystems and their diversity," said Wills. "The interplay we have found between and among species helps to explain how the numerous species in these complex ecosystems can buffer the ecosystems against environmental changes, enabling the ecosystems themselves to survive."Moving forward, the scientists plan to continue using the data to help tease out specific influences that are essential to ecosystem health."We want to show how we can maintain the diversity of the planet at the same time as we are preserving ecosystems that will aid our own survival," said Wills.
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Biology
| 2,021 |
April 29, 2021
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https://www.sciencedaily.com/releases/2021/04/210429142634.htm
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How diet controls RNA maturation
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Particularly sensitive to chemical modifications, messenger RNAs (mRNAs) are molecules responsible for transmitting the information encoded in our genome, allowing for the synthesis of proteins, which are necessary for the functioning of our cells. Two teams from the University of Geneva (UNIGE), Switzerland, in collaboration with the Norwegian University of Science and Technology (NTNU), have focused on a specific type of chemical modification -- called methylation -- of mRNA molecules in the small worm
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Several steps take place before a DNA-encoded gene produces the corresponding protein. One of the two strands of DNA is first transcribed into RNA, which then undergoes several processes, including splicing, before being translated into a protein. This process removes unnecessary non-coding sequences (introns) from the gene, leaving only the protein-coding sequences (exons). This mature form of RNA is called messenger RNA (mRNA).In addition to these processes, RNA -- but also DNA molecules -- can undergo a chemical modification: methylation. This consists in adding a methyl group (CH3) which allows to modify the fate of these molecules without altering their sequence. Deposited on the RNA or DNA in very specific places like "post-its," methyl groups indicate to the cell that a particular fate must be given to these molecules. Methylation of RNA is essential: mice without RNA methylation die at an early embryonic stage.Two neighboring teams at the UNIGE, one working on RNA regulation and the other specializing in DNA organisation in the worm This gene, whose mRNA is modified by methylation, encodes for the enzyme that produces the methyl donor. "It is therefore a self-regulating mechanism since the gene involved in producing a key factor required for methylation is itself regulated by methylation!," explains Mateusz Mendel, a researcher in the Department of Molecular Biology at the UNIGE Faculty of Science, and the first author of this study.Moreover, this modification is dependent on the quantity of nutrients received by the worms. "When nutrients are abundant, the mRNA is methylated, gene splicing is blocked, and the level of methyl donors decreases, which limits the number of possible methylation reactions. On the other hand, when there are few nutrients, there is no methylation of the particular RNA of this gene, so splicing is not blocked and the synthesis of methyl donors increases," reports Kamila Delaney, a researcher in the Department of Molecular Biology at the UNIGE Faculty of Science. Elements present in the food provide the raw materials required for producing the methyl donor, so methylation-dependent splicing inhibition puts a brake on its production under conditions of a rich diet. "Aberrant methylation reactions -- too much or too little -- are the cause of many diseases. The cell has set up this very sophisticated regulatory system to ensure a fair balance of methylations in the cell," summarizes Mateusz Mendel.Methylation of mRNAs at these specific sequences was discovered in the 1970s by scientists, including Ueli Schibler, a former professor at the UNIGE, before being forgotten. It took 40 years before researchers rediscovered its importance in gene regulation in 2012. With this study, scientists from the Department of Molecular Biology highlight the crucial role of methylation in the control of splicing and in the response to environmental changes.
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Biology
| 2,021 |
April 29, 2021
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https://www.sciencedaily.com/releases/2021/04/210429142632.htm
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How meningitis-causing bacteria may sense fever to avoid immune killing
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Researchers at Karolinska Institutet in Sweden have discovered a mechanism through which meningitis-causing bacteria can evade our immune system. In laboratory tests, they found that Streptococcus pneumoniae and Haemophilus influenzae respond to increasing temperatures by producing safeguards that keep them from getting killed. This may prime their defenses against our immune system and increase their chances of survival, the researchers say. The findings are published in the journal
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"This discovery helps to increase our understanding of the mechanisms these bacteria use to evade our normal immune defenses," says co-corresponding author Edmund Loh, researcher in the Department of Microbiology, Tumor and Cell Biology at Karolinska Institutet. "It could be an important piece of the puzzle in examining what turns this usually harmless bacterium into a lethal killer."Meningitis is an inflammation of the membranes surrounding the brain and the spinal cord. It can be caused by viruses, bacteria, fungi and parasites.Bacterial meningitis is one of the most severe types and a major cause of death and disability in children worldwide. Several kinds of bacteria can cause the infection, including the respiratory pathogens Streptococcus pneumoniae and Haemophilus influenzae, which can be attributed to some 200,000 meningitis-caused deaths annually.These two bacteria often reside in the nose and throat of healthy people without making them ill. In some cases they spread into the bloodstream and cause invasive diseases, but the reasons for this remain largely unknown.In this study, the researchers set out to investigate the connection between temperature changes and survival of these bacteria in a laboratory setting. The experiments were prompted by another recent finding that linked the temperature sensing abilities of the bacterium N. meningitidis to invasive meningococcal disease.One of the signs of an infection is elevated temperatures and fever, which typically boost our immune system's ability to fight illness. In this study, however, the researchers found that both S. pneumoniae and H. influenzae activated stronger immune protections when challenged with higher temperatures.They did so through mechanisms involving four specific so-called RNA thermosensors (RNATs), which are temperature-sensitive non-coding RNA molecules. These RNATs helped boost the production of bigger protective capsules and immune modulatory Factor H binding proteins, both of which help shield these bacteria from immune system attacks."Our results indicate that these temperature sensing RNATs create an additional layer of protection that helps the bacteria colonize their normal habitat in the nose and throat," says the paper's first author Hannes Eichner, PhD student at the same department. "Interestingly, we saw that these RNATs do not possess any sequence similarity, but all retain the same thermosensing ability, which indicates that these RNATs have evolved independently to sense the same temperature cue in the nasopharynx to avoid immune killing."More research is needed to understand exactly what triggers these pathogens to breach from the mucous membrane into the bloodstream and further into the brain. Future studies encompassing in vivo infection model are warranted to characterize the role of these RNATs during colonization and invasion, the researchers say.The work was supported by grants from the Knut and Alice Wallenberg Foundation, the Swedish Foundation for Strategic Research, the Swedish Research Council, the Stockholm County Council and Karolinska Institutet.
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Biology
| 2,021 |
April 29, 2021
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https://www.sciencedaily.com/releases/2021/04/210429142629.htm
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Multi-drug resistant infection about to evolve within cystic fibrosis patients
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Scientists have been able to track how a multi-drug resistant organism is able to evolve and spread widely among cystic fibrosis patients -- showing that it can evolve rapidly within an individual during chronic infection. The researchers say their findings highlight the need to treat patients with
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Around one in 2,500 children in the UK is born with cystic fibrosis, a hereditary condition that causes the lungs to become clogged up with thick, sticky mucus. The condition tends to decrease life expectancy among patients.In recent years, In a study published today in The team found two key processes that play an important part in the organism's evolution. The first is known as horizontal gene transfer -- a process whereby the bacteria pick up genes or sections of DNA from other bacteria in the environment. Unlike classical evolution, which is a slow, incremental process, horizontal gene transfer can lead to big jumps in the pathogen's evolution, potentially allowing it to become suddenly much more virulent.The second process is within-host evolution. As a consequence of the shape of the lung, multiple versions of the bacteria can evolve in parallel -- and the longer the infection exists, the more opportunities they have to evolve, with the fittest variants eventually winning out. Similar phenomena have been seen in the evolution of new SARS-CoV-2 variants in immunocompromised patients.Professor Andres Floto, joint senior author from the Centre for AI in Medicine (CCAIM) and the Department of Medicine at the University of Cambridge and the Cambridge Centre for Lung Infection at Royal Papworth Hospital, said: "What you end up with is parallel evolution in different parts of an individual's lung. This offers bacteria the opportunity for multiple rolls of the dice until they find the most successful mutations. The net result is a very effective way of generating adaptations to the host and increasing virulence."This suggests that you might need to treat the infection as soon as it is identified. At the moment, because the drugs can cause unpleasant side effects and have to be administered over a long period of time -- often as long as 18 months -- doctors usually wait to see if the bacteria cause illness before treating the infection. But what this does is give the bug plenty of time to evolve repeatedly, potentially making it more difficult to treat."Professor Floto and colleagues have previously advocated routine surveillance of cystic fibrosis patients to check for asymptomatic infection. This would involve patients submitting sputum samples three or four times a year to check for the presence of Using mathematical models, the team have been able to step backwards through the organism's evolution in a single individual and recreate its trajectory, looking for key mutations in each organism in each part of the lung. By comparing samples from multiple patients, they were then able to identify the key set of genes that enabled this organism to change into a potentially deadly pathogen.These adaptations can occur very quickly, but the team found that their ability to transmit between patients was constrained: paradoxically, those mutations that allowed the organism to become a more successful pathogen within the patient also reduced its ability to survive on external surfaces and in the air -- the key mechanisms by which it is thought to transmit between people.Potentially one of the most important genetic changes witnessed by the team was one that contributed towards Examining the DNA taken from patient samples is also important in helping understand routes of transmission. Such techniques are used routinely in Cambridge hospitals to map the spread of infections such as MRSA and C. difficile -- and more recently, SARS-CoV-2. Insights into the spread of Professor Julian Parkhill, joint senior author from the Department of Veterinary Medicine at the University of Cambridge, added: "The team have used their research to develop insights into the evolution of M. tuberculosis -- the pathogen that causes TB about 5,000 years ago. In a similar way to Dr Lucy Allen, Director of Research at the Cystic Fibrosis Trust, said: "This exciting research brings real hope of better ways to treat lung infections that are resistant to other drugs. Our co-funded Innovation Hub with the University of Cambridge really shows the power of bringing together world-leading expertise to tackle a health priority identified by people with cystic fibrosis. We're expecting to see further impressive results in the future coming from our joint partnership."The study was funded by the Wellcome Trust, Cystic Fibrosis Trust, NIHR Cambridge Biomedical Research Centre and The Botnar Foundation
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Biology
| 2,021 |
April 29, 2021
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https://www.sciencedaily.com/releases/2021/04/210429141938.htm
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New, rapid CRISPR/Cas9 method identifies key genes in zebrafish spinal cord regeneration
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A new, rapid screening approach uses CRISPR/Cas9 technology to identify immune system-related genes that play a crucial role in repairing zebrafish spinal cord injuries. Marcus Keatinge and Themistoklis Tsarouchas of the University of Edinburgh, U.K., and colleagues present these findings in the open-access journal
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In humans and other mammals, severed spinal-cord nerve connections do not heal, so a spinal cord injury may lead to permanent paralysis. In contrast, zebrafish are capable of recovering from spinal cord injury in a process that involves inflammation controlled by macrophages -- a type of immune system cell. However, the precise process by which macrophages aid spinal cord regeneration in zebrafish remains mysterious.To help clarify this process, Keatinge, Tsarouchas and colleagues developed a new method for rapidly identifying macrophage-related genes that are involved in zebrafish spinal cord regeneration. The strategy employs CRISPR/Cas9 technology, which enables researchers to target and disrupt specific genes, thereby revealing their function. Molecules known as synthetic RNA Oligo CRISPR guide RNAs (sCrRNAs) enable this gene-specific targeting.The researchers applied the new method to study spinal cord regeneration in larval zebrafish. Key to the method was a prescreening step in which they tested over 350 sCrRNAs that target genes already known to potentially play an important role in inflammation-related spinal cord regeneration. Introducing these sCrRNAs to the zebrafish enabled identification 10 genes that, when disrupted, impaired recovery from spinal cord injury.Further analysis narrowed the list to four genes that appear to be crucial for repair of severed spinal nerve connections, validating the novel method. One gene in particular, tgfb1, appears to play an essential signaling role in controlling inflammation during the recovery process.The new method and findings could help deepen understanding of spinal cord regeneration in zebrafish. The researchers also say the method could be adapted to screen for genes that play important roles in other biological processes, as well.The authors add, "Zebrafish can fully regenerate their spinal cords after injury. Using a new and very rapid screening platform, we discover genes of the immune system that are essential for regeneration. We envision our findings to lead to new insights into the inability of mammals to regenerate and our versatile screening platform to be adapted to other disease or injury models in zebrafish."
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Biology
| 2,021 |
April 29, 2021
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https://www.sciencedaily.com/releases/2021/04/210429123336.htm
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Corals that 'spit' algae
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Microalgae of the dinoflagellate group are known for their ability to survive in other animal cells. These tiny single-cell organisms have engaged in mutually beneficial relationships with corals since primeval times. By passing on critical nutrients to their hosts, dinoflagellates allow corals to thrive even in barren areas. A research team from the Centre for Organismal Studies (COS) of Heidelberg University recently discovered that such symbioses within the cell essentially depend on the ability of the algae to suppress the immune system of their host cell and thereby avoid being "spit out" again. At the same time, the researchers found indications that this cellular immune response is an evolutionarily ancient immune mechanism that is more widespread than previously assumed.
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This mechanism is known as vomocytosis. Contrary to previous assumptions, microalgae ingested by corals are not digested by the cell if they prove unsuitable as symbionts -- that is, partners in a symbiotic relationship. Instead, they are "spit out" again in the process of vomocytosis. Special dinoflagellates are able to specifically suppress this immune response of their host cells in order to remain in the cell. A study led by cell biologist Prof. Dr Annika Guse at the COS demonstrated how they are able to do that. "The challenge for the corals is to differentiate between beneficial and potentially harmful microorganisms. For their part, the algae have to circumvent the immune response of the host cell, establish an intracellular niche where they can survive, and coordinate their own cell functions with those of their host to efficiently exchange nutrients," explains the researcher.Until now, there has been no experimental evidence that could explain any of the conventional theories. Using the model system Exaiptasia diaphana (Aiptasia) of the sea anemone species, Prof. Guse's team recently uncovered how immune suppression by the symbionts helps the host cell to recognise suitable microalgae and tolerate them for the long term. The Aiptasia anemone larvae ingest the symbionts from the environment in the same way as coral larvae. Furthermore, their size and transparency make the larvae of this sea anemone perfect for high-resolution imaging and cellular experiments.Aiptasia continually ingests various particles from the environment without differentiating between suitable and unsuitable particles or organisms. Incompatible particles are "spit out" again after a certain amount of time. Symbionts avoid this process of vomocytosis, presumably by disrupting the signal pathways of the toll-like receptors (TLRs) of the host cell. These receptors play a critical role in activating the cell's own immune system and ensure that unwelcome intruders are detected and removed. In most animals, the toll-like receptors are controlled by the MyD88 gene. "We were able to prove that the algae symbionts suppress MyD88 and thus initiate symbiosis. That is how they elude vomocytosis," explains Prof. Guse.At the same time, the findings of the Heidelberg researchers indicate that vomocytosis involves a mechanism that is more widespread than assumed. Until now, it was believed that the expulsion of harmful intruders was self-initiated to evade the in part highly specialised immune responses of the potential host cell. The study of the Aiptasia model, however, suggests that this process can also be triggered by the host cell. The researchers therefore assume that vomocytosis is an evolutionarily ancient immune mechanism that corals or cnidarians like Aiptasia use to select appropriate symbionts. Prof. Guse: "This suggests that vomocytosis is an important process that led in the first place to the emergence of the intracellular lifestyle of the coral symbionts."
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Biology
| 2,021 |
April 29, 2021
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https://www.sciencedaily.com/releases/2021/04/210429112409.htm
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Baby's first stool can help predict risk of developing allergies
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It may seem like an unusual place to go looking for answers, but the contents of a baby's first diaper can reveal a lot about a newborn's future health.
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In a new study published today in "Our analysis revealed that newborns who developed allergic sensitization by one year of age had significantly less 'rich' meconium at birth, compared to those who didn't develop allergic sensitization," says the study's senior co-author Dr. Brett Finlay, a professor at the Michael Smith Laboratories and departments of biochemistry and molecular biology, and microbiology and immunology at UBC.Meconium, which is typically passed within the first day of life, is made up of a variety of materials ingested and excreted during development, ranging from skin cells, amniotic fluid and various molecules known as metabolites."Meconium is like a time capsule, revealing what the infant was exposed to before it was born. It contains all sorts of molecules encountered and accumulated from the mother while in the womb, and it then becomes the initial food source for the earliest gut microbes," says the study's lead author Dr. Charisse Petersen, a research associate in UBC's department of pediatrics.As part of the study, the researchers analyzed meconium samples from 100 infants enrolled in the CHILD Cohort Study (CHILD), a world-leading birth cohort study in maternal, newborn and child health research.They discovered that the fewer different types of molecules a baby's meconium contained, the greater the child's risk of developing allergies by one year. They also found that a reduction in certain molecules was associated with changes to key bacterial groups. These bacteria groups play a critical role in the development and maturation of a vast ecosystem of gut microbes, known as the microbiota, which is a powerful player in health and disease."This work shows that the development of a healthy immune system and microbiota may actually start well before a child is born -- and signals that the tiny molecules an infant is exposed to in the womb play a fundamental role in future health," says Dr. Petersen.Using a machine-learning algorithm, the researchers combined meconium, microbe and clinical data to predict with a high degree of accuracy (76 per cent), and more reliably than ever before, whether or not an infant would develop allergies by one year of age.The study findings have important implications for at-risk infants, say the researchers."We know that children with allergies are at the highest risk of also developing asthma. Now we have an opportunity to identify at-risk infants who could benefit from early interventions before they even begin to show signs and symptoms of allergies or asthma later in life," says the study's senior co-author Dr. Stuart Turvey, a professor in UBC's department of pediatrics, investigator at BC Children's Hospital and co-director of the CHILD Cohort Study.
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Biology
| 2,021 |
April 29, 2021
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https://www.sciencedaily.com/releases/2021/04/210429104947.htm
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Molecular biologists travel back in time 3 billion years
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A research group working at Uppsala University has succeeded in studying 'translation factors' -- important components of a cell's protein synthesis machinery -- that are several billion years old. By studying these ancient 'resurrected' factors, the researchers were able to establish that they had much broader specificities than their present-day, more specialised counterparts.
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In order to survive and grow, all cells contain an in-house protein synthesis factory. This consists of ribosomes and associated translation factors that work together to ensure that the complex protein production process runs smoothly. While almost all components of the modern translational machinery are well known, until now scientists did not know how the process evolved.The new study, published in the journal The researchers looked at several nodes in the evolutionary history of EF-Tu. The oldest proteins they created were approximately 3.3 billion years old."It was amazing to see that the ancestral EF-Tu proteins matched the geological temperatures prevailing on Earth in their corresponding time periods. It was much warmer 3 billion years ago and those proteins functioned well at 70°C, while 300 million year old proteins were only able to withstand 50°C," says Suparna Sanyal.The researchers were able to demonstrate that the ancient elongation factors are compatible with various types of ribosome and therefore can be classified as 'generalists', whereas their modern descendants have evolved to fulfil 'specialist' functions. While this makes them more efficient, they require specific ribosomes in order to function properly. The results also suggest that ribosomes probably evolved their RNA core before the other associated translation factors."The fact that we now know how protein synthesis evolved up to this point makes it possible for us to model the future. If the translation machinery components have already evolved to such a level of specialisation, what will happen in future, for example, in the case of new mutations?" ponders Suparna Sanyal.The fact that researchers have demonstrated that it is possible to recreate such ancient proteins, and that extremely old translation factors work well with many different types of ribosome, indicates that the process is of potential interest for protein pharmaceuticals research. If it turns out that other ancient components of protein synthesis were also generalists, it might be possible to use these ancient variants to produce therapeutic proteins in future with non-natural or synthetic components.
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Biology
| 2,021 |
April 29, 2021
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https://www.sciencedaily.com/releases/2021/04/210429104944.htm
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Light, in addition to ocean temperature, plays role in coral bleaching
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A study by University of Guam researchers has found that shade can mitigate the effects of heat stress on corals. The study, which was funded by the university's National Science Foundation EPSCoR grant, was published in February in the peer-reviewed Marine Biology Research journal.
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"We wanted to see what role light has in coral bleaching," said UOG Assistant Professor Bastian Bentlage, the supervisor and co-author of the study. "Usually, people talk about temperature as a cause for bleaching, but we show that both light and temperature work together."Previous UOG research led by Laurie J. Raymundo found that more than one-third of all coral reefs in Guam were killed from 2013 to 2017 over the course of multiple bleaching events. Coral bleaching is the process in which corals stressed by environmental changes expel the essential symbiotic algae that live in their tissues, causing them to turn white and often die.This latest study examined the resilience of staghorn corals (Acropora cf. pulchra) in heightened seawater temperatures. This species of coral is one of Guam's dominant reef-builders, and its habitats experience temperatures up to 97 degrees Fahrenheit during the hottest months of the year, leaving it vulnerable to bleaching episodes and population decline.A team of researchers -- including lead author Justin T. Berg, a UOG graduate student studying biology; Charlotte M. David, an undergraduate student from the University of Plymouth (England), and Melissa Gabriel, a UOG graduate student studying environmental science -- took coral samples from the Hagåtña reef flat and examined their health in the UOG Marine Laboratory under normal and elevated temperatures."One group was subjected to consistent baseline temperatures observed on Guam's reef flats," Bentlage said, "and another was set to temperatures that are projected to become the new normal over the next couple of decades."The researchers found that the corals took three weeks to recover from a week-long heat stress event. The experiment was then replicated to see how the corals would react if they were given shade while subjected to warmer temperatures."We found that when we put the shading over coral with increased seawater temperatures, it greatly increased photosynthetic yield of the symbiotic algae. Shade made a huge difference for coral health when you have high temperatures," Berg said.Shading is a practice already used in coral nurseries, Bentlage said, but it may not be practical to shade whole reefs in the ocean. Future studies can look into practical ways to reduce the impact of light on corals, particularly as they recover from periods of elevated temperatures."We saw the corals recover rather slowly," Berg said. "The length of recovery indicates that corals are vulnerable during this time and management efforts may be particularly necessary during this period to reduce coral mortality."Berg said the new knowledge may also help inform the best locations to successfully outplant corals."For example, slightly turbid waters could provide some shading to corals, making them less likely to bleach during periods of elevated sea surface temperatures," Berg said.
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Biology
| 2,021 |
April 29, 2021
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https://www.sciencedaily.com/releases/2021/04/210429104939.htm
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Time for a mass extinction metrics makeover
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Researchers at Yale and Princeton say the scientific community sorely needs a new way to compare the cascading effects of ecosystem loss due to human-induced environmental change to major crises of the past.
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For too long, scientists have relied upon metrics that compare current rates of species loss with those characterizing mass extinctions in the distant past, according to Pincelli Hull, an assistant professor of Earth and planetary sciences at Yale, and Christopher Spalding, an astrophysicist at Princeton.The result has been projections of extinction rates in the next few decades that are on the order of a hundred times higher than anything observed in the last few million years of the fossil record."The problem with using extinction rates this way is that their assessment is riddled with uncertainty," said Hull, who has conducted extensive research on mass extinctions of marine life in the ancient world. "We need a better thermometer for biodiversity crises."Furthermore, the researchers said, mass extinction predictions do not fully convey the severity of damage done to an ecosystem when species are depleted but not entirely wiped out.In a new study in the journal Part of the problem, they said, has to do with comparing extinctions found in the fossil record over millions of years with human-influenced extinctions from only the past century. Mass extinctions in the ancient world were typically characterized by "pulses" of extinctions, preceded and followed by quieter periods; the longer time frame reduces the historic average because it includes the surrounding quiet periods.What's more, there are large gaps in the ancient fossil record. For example, it is well documented that frog species today are at high risk of extinction -- yet frogs are only rarely found in the fossil record. In addition, certain habitats with many extinctions today -- such as islands -- are also not represented in the ancient fossil record. Rather, the fossil record tends to be dominated by larger species and geographically larger habitats."It's difficult to confidently deduce whether today's rates are objectively higher than those of the fossil record," Spalding said. "Meanwhile, we know that ecosystems may be totally decimated, yet suffer very few extinctions. In that sense, extinction rates may even underestimate our influence upon the biosphere."Spalding and Hull took pains to describe the perilous state of the natural world today, beyond the numbers of species extinctions. According to an Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) report in 2019, nearly 75% of all freshwater resources on Earth are used by crop and livestock production; human activities have significantly altered 75% of all ice-free terrestrial environments and 66% of marine environments.Spalding and Hull's proposal is to change the metric from species loss to changes in the rocks beneath their feet."Humans change the rock record as soon as they enter an area, whether it is agrarian societies, beaver trapping, or the damming of rivers," Hull said. "We completely change the way the Earth forms itself and this can be seen in the rocks left behind."The researchers said a variety of measurable metrics -- such as the chemical composition of sediments and grains of rocks -- are more readably comparable to ancient timescales."Historical comparisons offer the hope that we might begin to understand the relative scope and the eventual ramifications of our modification of the biosphere," Spalding said. "If we think these comparisons are important, we need to get them right."
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Biology
| 2,021 |
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