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December 11, 2020
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https://www.sciencedaily.com/releases/2020/12/201211115507.htm
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Gut microbiota plays a role in brain function and mood regulation
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Depression is a mental disorder that affects more than 264 million people of all ages worldwide. Understanding its mechanisms is vital for the development of effective therapeutic strategies. Scientists from the Institut Pasteur, Inserm and the CNRS recently conducted a study showing that an imbalance in the gut bacterial community can cause a reduction in some metabolites, resulting in depressive-like behaviors. These findings, which show that a healthy gut microbiota contributes to normal brain function, were published in
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The bacterial population in the gut, known as the gut microbiota, is the largest reservoir of bacteria in the body. Research has increasingly shown that the host and the gut microbiota are an excellent example of systems with mutually beneficial interactions. Recent observations also revealed a link between mood disorders and damage to the gut microbiota. This was demonstrated by a consortium of scientists from the Institut Pasteur, the CNRS and Inserm, who identified a correlation between the gut microbiota and the efficacy of fluoxetine, a molecule frequently used as an antidepressant. But some of the mechanisms governing depression, the leading cause of disability worldwide, remained unknown.Using animal models, scientists recently discovered that a change to the gut microbiota brought about by chronic stress can lead to depressive-like behaviors, in particular by causing a reduction in lipid metabolites (small molecules resulting from metabolism) in the blood and the brain.These lipid metabolites, known as endogenous cannabinoids (or endocannabinoids), coordinate a communication system in the body which is significantly hindered by the reduction in metabolites. Gut microbiota plays a role in brain function and mood regulationEndocannabinoids bind to receptors that are also the main target of THC, the most widely known active component of cannabis. The scientists discovered that an absence of endocannabinoids in the hippocampus, a key brain region involved in the formation of memories and emotions, resulted in depressive-like behaviors.The scientists obtained these results by studying the microbiotas of healthy animals and animals with mood disorders. As Pierre-Marie Lledo, Head of the Perception and Memory Unit at the Institut Pasteur (CNRS/Institut Pasteur) and joint last author of the study, explains: "Surprisingly, simply transferring the microbiota from an animal with mood disorders to an animal in good health was enough to bring about biochemical changes and confer depressive-like behaviors in the latter."The scientists identified some bacterial species that are significantly reduced in animals with mood disorders. They then demonstrated that an oral treatment with the same bacteria restored normal levels of lipid derivatives, thereby alleviating the depressive-like behaviors. These bacteria could therefore serve as an antidepressant. Such treatments are known as "psychobiotics.""This discovery shows the role played by the gut microbiota in normal brain function," continues Gérard Eberl, Head of the Microenvironment and Immunity Unit (Institut Pasteur/Inserm) and joint last author of the study. If there is an imbalance in the gut bacterial community, some lipids that are vital for brain function disappear, encouraging the emergence of depressive-like behaviors. In this particular case, the use of specific bacteria could be a promising method for restoring a healthy microbiota and treating mood disorders more effectively.
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Zoology
| 2,020 |
December 10, 2020
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https://www.sciencedaily.com/releases/2020/12/201210145814.htm
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Embryonic development in a petri dish
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By growing mouse stem cells in a special gel, a Berlin research team succeeded to grow structures similar to parts of an embryo. The trunk-like structures develop the precursors for neural, bone, cartilage and muscle tissues from cellular clumps within five days. This could allow the investigation of the effects of pharmacological agents more effectively in the future -- and on a scale that would not be possible in living organisms. The results were published in the journal
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It would certainly spare mothers the hardships of pregnancy, but mammals do not grow in eggs. In a way, this is also impractical for science. While embryos of fish, amphibians or birds can be easily watched growing, mammalian development evades the gaze of the observer as soon as the embryo implants into the uterus. This is precisely the time when the embryo undergoes profound changes in shape and develops precursors of various organs -- a highly complex process that leaves many questions unanswered.But now a research team at the Max Planck Institute for Molecular Genetics (MPIMG) in Berlin succeeded in replicating a central phase of embryonic development in a cell culture approach by growing the core portion of the trunk from mouse embryonic stem cells for the first time. The method recapitulates the early shape-generating processes of embryonic development in the Petri dish.The structures are roughly a millimeter in size and possess a neural tube from which the spinal cord would develop. Furthermore, they have somites, which are the precursors of skeleton, cartilage and muscle. Some of the structures even develop the precursors of internal organs such as the intestine. After about five days, the parallels to normal development end."This model of embryonic development starts a new era," says Bernhard G. Herrmann, Director at the MPIMG and head of the Institute of Medical Genetics at Charité -- Universitätsmedizin Berlin. "This allows us to observe embryogenesis of the mouse directly, continuously, and with large parallel numbers of samples -- which would not be possible in the animal."It is considered quite easy to isolate early embryos from the tube or the uterus and grow them in the Petri dish, as long as they are still free to move. But once the embryo has implanted in the endometrium, isolation becomes extremely difficult."We can obtain more detailed results more quickly, and without the need for animal research," says Alexander Meissner, who like Herrmann is Director at the MPIMG and jointly supervised the study that was published in the current issue of the journal Science. "Of the more complex processes such as morphogenesis, we usually only get snapshots -- but this changes with our model."So far, it has only been possible to grow cell clusters from embryonic stem cells, so-called gastruloids. "Cellular assemblies in gastruloids develop to a similar extent like in our trunk-like structures, but they do not assume the typical appearance of an embryo," says Jesse Veenvliet, one of the two lead authors of the study. "The cell clusters lack the signals that trigger their organization into a meaningful arrangement."In the cell culture, the required signal is generated by a special gel that mimics the properties of the extracellular matrix. This jelly-like substance consists of a complex mixture of extended protein molecules that is secreted by cells and is found throughout the body as an elastic filling material, especially in connective tissues. The utilization of this gel is the crucial "trick" of the new method."The gel provides support to the cultured cells and orients them in space; they can distinguish inside from outside, for example," says Veenvliet. It also prevents secreted molecules such as the matrix protein fibronectin from leaking into the cell culture medium. "The cells are able to establish better communication, which leads to better self-organization."After four to five-days, the team dissolved the structures into single cells and analyzed them individually. "Even though not all cell types are present in the trunk-like structures, they are strikingly similar to an embryo of the same age," says Adriano Bolondi, who is also lead author of the paper. Together with bioinformatician Helene Kretzmer, Bolondi and Veenvliet compared the genetic activity of the structures with actual mouse embryos. "We found that all essential marker genes were activated at the right time in the right places in the embryoids, with only a small number of genes being out of line," says Bolondi.The researchers introduced a mutation with known developmental effects into their model and could recreate the results from "real" embryos, further validating their model. They also provide examples of manipulating the developmental process with chemical agents.
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Zoology
| 2,020 |
December 10, 2020
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https://www.sciencedaily.com/releases/2020/12/201210145719.htm
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Natural environmental conditions facilitate the uptake of microplastics into living cells
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The environment is polluted by microplastics worldwide. The tiny particles enter food chains, and thereby the digestive systems of animals and humans; moreover, they can be inhaled. Instead of being excreted, small microplastics can be incorporated into the body tissue. A research team at the University of Bayreuth has now discovered that microplastic particles find their way into living cells more easily if they were exposed to natural aquatic environments, i.e. fresh water and seawater. Biomolecules occurring in the water are deposited on the microplastic surfaces, which promote the internalization of the particles into cells. The researchers present their results in "
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The interdisciplinary research team led by Prof. Dr. Christian Laforsch (Animal Ecology) and Prof. Dr. Holger Kress (Biological Physics) focused on microplastic particles with a diameter of around three micrometres for the new study. Particles of this size are often found in the environment. To simulate their exposure in the environment, some microplastic particles were placed in fresh water from an artificial pond, while other microplastic particles were placed in salt water from a marine aquarium. Biomolecules were deposited on the surfaces of these particles within two weeks exposure time."Spectroscopic examinations indicate that these biomolecules are carbohydrates, amino acids, nucleic acids, and proteins. We are talking about an 'eco-corona' that forms on the microplastic particles in a natural environment," explains Anja Ramsperger M.Sc., first author of the new study and PhD student at the Department of Animal Ecology I and in the Biological Physics group.The research team has now examined the microplastic particles coated with biomolecules to see how they interact with living cells. For this purpose, cells from an established mouse cell line were used. In order to distinguish whether the particles are actually internalized or only adhere to the exterior of the cells, important components of the cell interior, the actin filaments, were stained. On the resulting microscopic images, the internalized particles could be recognised as "dark holes." "The fluorescent labeling of the actin filaments enabled us to see exactly which particles were internalized by the cells. Based on spectroscopic methods, we verified that these particles were indeed microplastics -- or more precisely: polystyrene particles -- and not accidental impurities," says Prof. Dr. Holger Kress, Professor of Biological Physics at the University of Bayreuth. The control group in this experiment consisted of microplastic particles that had been incubated in ultra pure water and were therefore not coated with an eco-corona. It turned out that these untreated microplastic particles were only occasionally internalized by the cells."Our study supports the assumption that microplastics which were exposed to the natural environment -- and are therefore coated with biomolecules -- not only pass through the digestive tract when ingested with food, but may also be incorporated into tissue. The coating of biomolecules may act as a kind of Trojan horse that allows plastics to be internalized into living cells. The precise damage that the particles can cause here has not yet been sufficiently investigated. It is also still largely unclear which of the properties of microplastics are actually responsible for any negative effects. These questions represent a central topic for the 'Microplastics' Collaborative Research Centre in Bayreuth. Finding precise answers to these questions is important in order to be able to develop new materials and solutions in this area in the future," says Prof. Dr. Christian Laforsch, spokesperson of the DFG-funded "Microplastics" Collaborative Research Centre at the University of Bayreuth, and Chair of Animal Ecology I."The interdisciplinary network in the 'Microplastics' Collaborative Research Centre enables us to examine the complex questions that this topic poses with the necessary diversity of research approaches and perspectives. The need for an interdisciplinary approach is evident in the study now published. Scientists from various scientific disciplines at the University of Bayreuth have contributed to it -- from animal ecology, to polymer chemistry, to biological physics," says Laforsch.
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Zoology
| 2,020 |
December 9, 2020
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https://www.sciencedaily.com/releases/2020/12/201209140356.htm
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New 'sea dragon' discovered off UK coastline
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An amateur fossil hunter has unearthed a new type of prehistoric 'sea dragon' on the beach of the UK's Dorset coast.
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The new 2m-long ichthyosaurus is named 'Etches sea dragon', after fossil collector Dr Steve Etches MBE, who found it buried head-first in limestone. Ichthyosaurs are called sea dragons for their usually very large teeth and eyes.He thought its teeth were unusual, so he passed it on to experts at the University of Portsmouth to identify.There, a Masters student, Megan Jacobs, who has spent several years working on ichthyosaurs, identified it as a new genus and species, which lived 150 million years ago.The find is the UK's fifth known ichthyosaur from the Late Jurassic period, and by far the smallest so far.The research is published in the online journal The specimen was found near Kimmeridge Bay -- part of the Jurassic Coast World Heritage Site -- in a limestone known as the white stone band. When it died, the seafloor would have been a very soft ooze, allowing the front half of the animal to sink into the mud, before scavengers came along and ate the tail end.Being buried in a bed of soft ooze meant it was preserved in exceptional condition and even some of its soft tissues were preserved.Megan said: "Skeletons of Late Jurassic ichthyosaurs in the UK are extremely rare, so, after doing some research, comparing it with those known from other Late Jurassic deposits around the world, and not being able to find a match was very exciting."Thalassodraco etchesi is a beautifully preserved ichthyosaur, with soft tissue preservation making it all the more interesting."Steve's incredible collection contains many new and exciting animals, and being given the chance to describe this ichthyosaur was a real privilege."Ichthyosaurs were highly adapted marine predators, with a streamlined body for gliding through the water, incredibly large eyes for enhanced vision, and elongated jaws full of conical teeth, well suited for catching slippery fish and squid.Thalassodraco etchesi has a deep ribcage, small forelimbs and hundreds of tiny, delicate, smooth teeth.Professor David Martill, who leads the vertebrate palaeontology research at the University of Portsmouth, said: "Steve is an exceptional fossil collector and although he is sometimes referred to as an amateur collector, he has done so much for palaeontology that he has been awarded an MBE, and is truly a pro."If it were not for collectors like Steve, scientists would have very few specimens to work on."Now that the new sea dragon has been named, work will begin on investigating its biology.Professor Martill said: "There are a number of things that make this animal special, not least of which is its unusual rib cage and small flippers. It may have swum with a distinctive style from other ichthyosaurs."The specimen is on display alongside Dr Etches' other many fossils in his museum in Dorset, the Etches Collection, which he built to house the many discoveries he's made over a lifetime of fossil hunting.Dr Etches said: "I'm very pleased that this ichthyosaur has been found to be new to science, and I'm very honoured for it to be named after me."It's excellent that new species of ichthyosaurs are still being discovered, which shows just how diverse these incredible animals were in the Late Jurassic seas."Thalassodraco etchesi is closely related to Nannopterygius, a genus widespread across Europe, Russia and the Arctic.Ichthyosaurs were highly successful marine reptiles, living in the seas for most of the Mesozoic, appearing around 248 million years ago in the Triassic period, and becoming extinct in the Late Cretaceous at around 90 million years ago.Some of the last surviving ichthyosaurs have been found in the chalk on the Isle of Wight, but the first specimens to be described scientifically were found by Mary Anning at Lyme Regis at the beginning of the 19th century from rocks of Early Jurassic age.The largest ichthyosaurs are from the Triassic period of North America some of which had a skull length of nearly five metres -- 10 times bigger than the skull of this newest discovery.
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Zoology
| 2,020 |
December 9, 2020
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https://www.sciencedaily.com/releases/2020/12/201209140336.htm
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'Spooky Interactions', shocking adaptations discovered in electric fish of Brazil's Amazon
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A study of weakly electric fishes from a remote area of the Brazilian Amazon Basin has not only offered a unique window into how an incredibly rare fish has adapted to life in caves over tens of thousands of years, it has also revealed for the first time that electric fish are able to interact with each other over longer distances than known possible in a way similar to AM radio.
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In findings published in the journal The study, which analyzed the fishes' electric-based communication and behavior, has detailed the discovery that weakly electric fishes tap into a special channel for long-distance messaging via changes in the amplitude of electrical signals sent to one another. Researchers have adapted Einstein's famous quote on the theory of quantum entanglement -- "spooky interaction at a distance" -- to describe how the weakly electric fishes perceive these social messages, altering each other's behavior at distances up to several meters apart.Of the nearly 80 species of cavefish known today to have evolved from surface-dwelling fish, all have developed sensory enhancements of some kind for enduring cave life, commonly adapting over millions of years while losing sensory organs they no longer need in the process.However, biologists have questioned how weakly electric fishes, which use their electrical senses for navigating the dark and murky conditions of the Amazon River, might also adapt -- either evolving heightened electric senses to see and communicate in absolute darkness, or by powering down their electric fields to save on energetic cost when most caves have few food resources."One of the big questions about fish that successfully adapt to living in caves is how they adapt to life without light," said Eric Fortune, lead author of the study and biologist at New Jersey Institute of Technology (NJIT). "My colleagues were split between two groups ... one group that predicted that the electric fields of the cavefish would be weaker due to limited food supplies, and another that bet that the electric fields would be stronger, allowing the fish to use their electric signals to see and talk more clearly in the complete darkness of the cave."It seems that using their electric sense to detect prey and communicate with each other is quite valuable to these animals; they have greater electric field strengths. Interestingly, our analysis of their electric fields and movement shows that they can communicate at distances of meters, which is quite a long way for fish that are around 10cm in length.""Nearly all research of cavefish species until now has been limited to behavioral experiments in labs, and that is why this study is special," said Daphne Soares, NJIT associate professor of biology and co-author on the study. "This is the first time we've been able to continuously monitor the behavior of any cavefish in their natural setting over days. We've gained great insight into their nervous system and specialized adaptations for cave life, but it's just as exciting to learn how sociable and chatty they are with each other ... it's like middle school."For the investigation, NJIT and Johns Hopkins researchers teamed with biologist Maria Elina Bichuette from the Federal University of São Carlos, who began studying the two groups of fish nearly two decades ago in the remote São Vicente II Cave system of Central Brazil's Upper Tocantins river basin.Over several days, the team applied a customized electric fish-tracking technique involving placing electrode grids throughout the fishes' water habitats to record and measure the electric fields generated by each fish, allowing the team to analyze the fishes' movements and electricity-based social interactions.The researchers were able to track more than 1,000 electrical-based social interactions over 20-minute-long recordings taken from both surface and cavefish populations, discovering hundreds of specialized long-distance exchanges."When I began studying these fishes, we could watch behavior associated with these fishes' unique and specialized morphology, but in this project, it was fascinating to apply these new technical approaches to reveal just how complex and refined their communication could be," said Bichuette."Basically, our evidence shows that the fishes are talking to each other at distance through electricity using a secret hidden channel, amplitude modulations that emerge through the summation of their electric signals. It is not unlike how an AM radio works, which relies on amplitude modulations of a radio signal." said Fortune.The recordings also showed that strengths of electric discharges in the cavefish were about 1.5 times greater than those of surface fish despite coming at a cost of up to a quarter of their overall energy budget. The team conducted CT scans of both species, showing that the cavefish also possess relatively larger electric organs than their stream-mates, which could explain the source of the cavefishes' extra electrical power.Another consequence of trading their eyes and surface life for heightened electrosensory perception is that the cavefish were more social and territorial at all hours. Unlike their freely-foraging surface relatives that sleep during the day and forage at night, the cavefish lacked a day-night cycle.For now, the discovery of the fishes' AM radio-style distant interactions is noted by Fortune as the first of its kind reported among electric cavefish, though he says similar phenomena is now being reported in some other species as well, recently by researchers in Germany who have observed a form of long-distance electrical communication among a group of fish known as Apteronotus. Fortune says the finding could have implications for the field of neurobiology, where weakly electric fish is a unique and powerful model for exploring the nature of the brain-body connection in other animals including humans."Electric fish are great systems for understanding the neural basis of behavior, so we have been studying their brains for decades," said Fortune. "These new data are forcing a reexamination of the neural circuits used for the control of behavior of these fishes."
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Zoology
| 2,020 |
December 9, 2020
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https://www.sciencedaily.com/releases/2020/12/201209124925.htm
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DeepLabCut-Live! real-time marker-less motion capture for animals
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Gollum in "The Lord of the Rings," Thanos in the "Avengers," Snoke in "Star Wars," the Na'vi in "Avatar": we have all experienced the wonders of motion-capture, a cinema technique that tracks an actor's movements and "translates" them into computer animation to create a moving, emoting -- and maybe one day Oscar-winning -- digital character.
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But what many might not realize is that motion capture isn't limited to the big screen, but extends into science. Behavioral scientists have been developing and using similar tools to study and analyze the posture and movement of animals under a variety of conditions. But motion-capture approaches also require that the subject wears a complex suit with markers that let the computer "know" where each part of the body is in three-dimensional space. That might be okay for a professional actor, but animals tend to resist dressing up.To solve the problem, scientists have begun combining motion-capture with deep learning, a method that lets a computer essentially teach itself how to optimize performing a task, e.g., recognizing a specific "key-point" in videos. The idea is to teach the computer to track and even predict the movements or posture of an animal without the need for motion capture markers.But to be of meaningful use to behavioral science, "marker-less" tracking tools must also allow scientists to quickly -- literally in real-time -- control or stimulate the neural activity of the animal. This is particularly important in experiments that try to work out which part of the nervous system underlies a specific movement of posture.One of the scientists spearheading the marker-less approach is Mackenzie Mathis who recently joined EPFL's School of Life Sciences from Harvard. Mathis' lab has been developing a deep-learning software toolbox named DeepLabCut, that can track and identify animal movements in real time directly from video. Now, in a paper published in DeepLabCut was originally developed in order to study and analyze the way animals adapt their posture in response to changes in their environment. "We're interested in how neural circuits control behavior and in particular in how animals adapt to quick changes in their environment," says Mathis."For example, you pour coffee in a mug and when it's full it has a particular weight. But, as you drink it the weight changes, yet you don't need to actively think about changing your grip force or how much you have to lift your arm to reach your mouth. This is a very natural thing we do and we can adapt to these changes very quickly. But this actually involves a massive amount of interconnected neurocircuitry, from the cortex all the way to the spinal cord."DLC-Live!, the new update to a state-of-the-art "animal pose estimation package" that uses tailored networks to predict the posture of animals based on video frames, which offline allows for up to 2,500 FPS on a standard GPU. Its high-throughput analysis makes it invaluable for studying and probing the neural mechanisms of behavior. Now, with this new package, it's low-latency allows researchers to give animals feedback in real time and test the behavioral functions of specific neural circuits. And, more importantly, it can interface with hardware used in posture studies to provide feedback to the animals."This is important for things in our own research program where you want to be able to manipulate the behavior of an animal," says Mathis. "For example, in one behavioral study we do, we train a mouse to play a video game in the lab, and we want to shut down particular neurons or brain circuits in a really specific time window, i.e., trigger a laser to do optogenetics or trigger an external reward.""We wanted to make DLC-Live! super user-friendly and make it work for any species in any setting," she adds. "It's really modular and can be used in a lot of different contexts; the person who's running the experiments can set up kind of the conditions and what they want to trigger quite easily with our graphical user interface. And we've also built in the ability to use it with other common neuroscience platforms." Two of those commonly used platforms are Bonsai and Autopilot, and in the paper, Mathis and her colleagues who developed those software packages show how DLC-Live! can easily work with them."It's economical, it's scalable, and we hope it's a technical advance that allows even more questions to be asked about how the brain controls behavior," says Mathis.
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Zoology
| 2,020 |
December 9, 2020
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https://www.sciencedaily.com/releases/2020/12/201209115201.htm
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Archaeopteryx fossil provides insights into the origins of flight
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Flying birds moult their feathers when they are old and worn because they inhibit flight performance, and the moult strategy is typically a sequential molt. Moulting is thought to be unorganised in the first feathered dinosaurs because they had yet to evolve flight, so determining how moulting evolved can lead to better understanding of flight origins.
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However, evidence of the transition to modern moulting strategies is scarce in the fossil record. Recently, Research Assistant Professor Dr Michael PITTMAN from the Research Division for Earth and Planetary Science, as well as Vertebrate Palaeontology Laboratory, at the Faculty of Science of the University of Hong Kong (HKU), Thomas G KAYE of the Foundation for Scientific Advancement (Arizona, USA) and William R WAHL of the Wyoming Dinosaur Center (Wyoming, USA), jointly discovered the earliest record of feather moulting from the famous early fossil bird Archaeopteryx found in southern Germany in rocks that used to be tropical lagoons ~150 million years ago. The findings were published in The most common moult strategy in modern birds is a sequential moult, where feathers are lost from both wings at the same time in a symmetrical pattern. The sequence of feather loss follows two different strategies: The first strategy is a numerically sequential molt where feathers are lost in numerical order and is the most common among passerines birds, also known as songbirds and perching birds; the second strategy is a centre-out strategy where a centre feather is lost first, and then subsequent feathers are shed outwards from this centre point; this is more common in non-passerine birds such as falcons. This strategy minimises the size of the aerodynamic hole in the wing, which allows falcons to better maintain their flight performance during the moult for hunting.Laser-Stimulated Fluorescence imaging co-developed at HKU revealed feather sheaths on the Thermopolis specimen of Archaeopteryx that are otherwise invisible under white light. "We found feather sheaths mirrored on both wings. These sheaths are separated by one feather and are not in numerical sequential order. This indicates that Archaeopteryx used a sequential centre-out moulting strategy, which is used in living falcons to preserve maximum flight performance," said Kaye. This strategy was therefore already present at the earliest origins of flight."The centre-out moulting strategy existed in early flyers and would have been a very welcome benefit because of their otherwise poor flight capabilities. They would have appreciated any flight advantage they could obtain," said Pittman. "This discovery provides important insights into how and when birds refined their early flight capabilities before the appearance of iconic but later flight-related adaptations like a keeled breastbone (sternum), fused tail tip (pygostyle) and the triosseal canal of the shoulder," added Pittman.This study is part of a larger long-term project by Pittman and Kaye and their team of collaborators to better understand the origins of flight (see notes).
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Zoology
| 2,020 |
December 8, 2020
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https://www.sciencedaily.com/releases/2020/12/201208090022.htm
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Smellicopter: An obstacle-avoiding drone that uses a live moth antenna to seek out smells
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One huge advantage of drones is that these little robots can go places where people can't, including areas that might be too dangerous, such as unstable structures after a natural disaster or a region with unexploded devices.
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Researchers are interested in developing devices that can navigate these situations by sniffing out chemicals in the air to locate disaster survivors, gas leaks, explosives and more. But most sensors created by people are not sensitive or fast enough to be able to find and process specific smells while flying through the patchy odor plumes these sources create.Now a team led by the University of Washington has developed Smellicopter: an autonomous drone that uses a live antenna from a moth to navigate toward smells. Smellicopter can also sense and avoid obstacles as it travels through the air. The team published these results Oct. 1 in the journal "Nature really blows our human-made odor sensors out of the water," said lead author Melanie Anderson, a UW doctoral student in mechanical engineering. "By using an actual moth antenna with Smellicopter, we're able to get the best of both worlds: the sensitivity of a biological organism on a robotic platform where we can control its motion."The moth uses its antennae to sense chemicals in its environment and navigate toward sources of food or potential mates."Cells in a moth antenna amplify chemical signals," said co-author Thomas Daniel, a UW professor of biology who co-supervises Anderson's doctoral research. "The moths do it really efficiently -- one scent molecule can trigger lots of cellular responses, and that's the trick. This process is super efficient, specific and fast."The team used antennae from the Manduca sexta hawkmoth for Smellicopter. Researchers placed moths in the fridge to anesthetize them before removing an antenna. Once separated from the live moth, the antenna stays biologically and chemically active for up to four hours. That time span could be extended, the researchers said, by storing antennae in the fridge.By adding tiny wires into either end of the antenna, the researchers were able to connect it to an electrical circuit and measure the average signal from all of the cells in the antenna. The team then compared it to a typical human-made sensor by placing both at one end of a wind tunnel and wafting smells that both sensors would respond to: a floral scent and ethanol, a type of alcohol. The antenna reacted more quickly and took less time to recover between puffs.To create Smellicopter, the team added the antenna sensor to an open-source hand-held commercially available quadcopter drone platform that allows users to add special features. The researchers also added two plastic fins on the back of the drone to create drag to help it be constantly oriented upwind."From a robotics perspective, this is genius," said co-author and co-advisor Sawyer Fuller, a UW assistant professor of mechanical engineering. "The classic approach in robotics is to add more sensors, and maybe build a fancy algorithm or use machine learning to estimate wind direction. It turns out, all you need is to add a fin."Smellicopter doesn't need any help from the researchers to search for odors. The team created a "cast and surge" protocol for the drone that mimics how moths search for smells. Smellicopter begins its search by moving to the left for a specific distance. If nothing passes a specific smell threshold, Smellicopter then moves to the right for the same distance. Once it detects an odor, it changes its flying pattern to surge toward it.Smellicopter can also avoid obstacles with the help of four infrared sensors that let it measure what's around it 10 times each second. When something comes within about eight inches (20 centimeters) of the drone, it changes direction by going to the next stage of its cast-and-surge protocol."So if Smellicopter was casting left and now there's an obstacle on the left, it'll switch to casting right," Anderson said. "And if Smellicopter smells an odor but there's an obstacle in front of it, it's going to continue casting left or right until it's able to surge forward when there's not an obstacle in its path."Another advantage to Smellicopter is that it doesn't need GPS, the team said. Instead it uses a camera to survey its surroundings, similar to how insects use their eyes. This makes Smellicopter well-suited for exploring indoor or underground spaces like mines or pipes.During tests in the UW research lab, Smellicopter was naturally tuned to fly toward smells that moths find interesting, such as floral scents. But researchers hope that future work could have the moth antenna sense other smells, such as the exhaling of carbon dioxide from someone trapped under rubble or the chemical signature of an unexploded device."Finding plume sources is a perfect task for little robots like the Smellicopter and the Robofly," Fuller said. "Larger robots are capable of carrying an array of different sensors around and using them to build a map of their world. We can't really do that at the small scale. But to find the source of a plume, all a robot really needs to do is avoid obstacles and stay in the plume while it moves upwind. It doesn't need a sophisticated sensor suite for that -- it just needs to be able to smell well. And that's what the Smellicopter is really good at."
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Zoology
| 2,020 |
December 2, 2020
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https://www.sciencedaily.com/releases/2020/12/201202192719.htm
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What social distancing does to a fish brain
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Have you recently wondered how social-distancing and self-isolation may be affecting your brain? An international research team led by Erin Schuman from the Max Planck Institute for Brain Research discovered a brain molecule that functions as a "thermometer" for the presence of others in an animal's environment. Zebrafish "feel" the presence of others via mechanosensation and water movements -- which turns the brain hormone on.
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Varying social conditions can cause long-lasting changes in animal behavior. Social isolation, for instance, can have devastating effects on humans and other animals, including zebrafish. The brain systems that sense the social environment, however, are not well understood. To probe whether neuronal genes respond to dramatic changes in the social environment, graduate student, Lukas Anneser, and colleagues raised zebrafish either alone or with their kin for different periods of time. The scientists used RNA sequencing to measure the expression levels of thousands of neuronal genes."We found a consistent change in expression for a handful of genes in fish that were raised in social isolation. One of them was parathyroid hormone 2 (pth2), coding for a relatively unknown peptide in the brain. Curiously, pth2 expression tracked not just the presence of others, but also their density. Surprisingly, when zebrafish were isolated, pth2 disappeared in the brain, but its expression levels rapidly rose, like a thermometer reading, when other fish were added to the tank," explains Anneser.Thrilled by this discovery, the scientists tested if the effects of isolation could be reversed by putting the previously isolated fish into a social setting. "After just 30 minutes swimming with their kin, there was a significant recovery of the pth2 levels. After 12 hours with kin the pth2 levels were indistinguishable from those seen in socially-raised animals," says Anneser. "This really strong and fast regulation was unexpected and indicated a very tight link between gene expression and the environment."So which sensory modality do the animals use to detect others and drive changes in gene expression? "It turned out that the sensory modality that controls pth2 expression was not vision, taste or smell, but rather mechanosensation -- they actually 'felt' the physical movements of the swimming neighboring fish," explains Schuman.Fish perceive movement ("mechano-sense") in their immediate vicinity via a sensory organ called the lateral line. To test the role of mechanosensation in driving pth2 expression, the team ablated the mechanosensitive cells within the fish's lateral line. In previously isolated animals, the ablation of the lateral line cells prevented rescue of the neuro-hormone that was usually induced by the presence of other fish.Just as we humans are sensitive to touch, zebrafish appear to be specifically tuned to swimming motion of other fish. The scientists saw changes in pth2 levels caused by water movements that is triggered by conspecifics in the tank. "Zebrafish larvae swim in short bouts. We mimicked this water stimulation by programming a motor to create artificial fish movements. Intriguingly, in previously isolated fish the artificial movements rescued pth2 levels just like the real neighboring fish," explains Anneser."Our data indicate a surprising role for a relatively unexplored neuropeptide, Pth2- it tracks and responds to the population density of an animal's social environment. It is clear that the presence of others can have dramatic consequences on an animal's access to resources and ultimate survival -- it is thus likely that this neuro-hormone will regulate social brain and behavioral networks," concludes Schuman.
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Zoology
| 2,020 |
November 30, 2020
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https://www.sciencedaily.com/releases/2020/11/201130113552.htm
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Getting to the core of nuclear speckles
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When the famous Spanish physician Santiago Ramón y Cajal looked through his microscope in 1910, he discovered irregular and "transparent lumps" that appeared throughout the nucleus of a neuron. What these nuclear speckles are all about is still largely unclear, even though the biological and medical sciences have experienced several revolutions since then. "Even though we know quite a bit about their function, we didn't know how nuclear speckles originate, i.e. what their core consists of," says Tuçe Akta from the Max Planck Institute for Molecular Genetics.
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A Berlin team of scientists led by the Max Planck Research Group leader now identified the molecules that form the scaffold of nuclear speckles.The two proteins in question are SON and SRRM2, which are present in different variations throughout the entire animal kingdom. Both molecules are involved in the processing of RNA, which is produced when genes are transcribed. Without these proteins, the speckles dissolve.Unlike other cell structures, speckles do not have a membrane envelope. They consist of an aggregation of molecules that can dynamically dissolve and reassemble, exhibiting the properties of solids as well as those of liquids. These "condensates" can be found throughout the cell. "Each cellular condensate has a protein that represents its nucleus -- in the case of nuclear speckles, there are two," says Akta.It is no coincidence that past attempts to identify the lowest common denominator of the mysterious structures have not been successful. "For 30 years scientists have been staining nuclear speckles with a reagent that they did not know very well," says Akta. "We did not realize that we have been in the dark for decades."Since the early nineties, nuclear speckles have been visualised with a substance called SC35, which is an antibody that specifically attaches to certain sites in the speckles and can stain them with the help of pigments. Until recently, however, it was assumed that the antibody only recognizes the small protein SRSF2 -- an assumption that now turned out to be wrong. "We wanted to use the antibody as a bait to fish for speckles in the cell," says brahim Avar Ilk, the lead author of the study. "It was a great surprise to find the protein SRRM2, which was not the intended prey for our experiment." It turned out that the antibody not only adheres to the already known SRSF2, but especially and particularly well to SRRM2.While the sequence of SRRM2 varies widely in different animal species, the protein has a small section that has been preserved over hundreds of millions of years of evolution. Looking for similar proteins in the evolutionary family tree, the researchers also noticed the protein SON, which was considered by other research groups as a possible critical component of the speckles, too. "We had the idea that the combination of the two proteins could be the fundamental building block of the speckles," says Ilk.To test their hypothesis, the team grew human cells with the genes for either SRRM2 or SON switched off. This resulted in only spherical remnants of the speckles in the cell's nuclei. Once the researchers knocked down both proteins simultaneously, all the speckles dissolved completely and associated proteins were found to be distributed throughout the cell nucleus. "We concluded that SRRM2 and SON must be the scaffold for nuclear speckles," says Ilk. "Next, we will investigate how the two proteins bind to other molecules and how this process is controlled."But the results have even more, and perhaps far-reaching consequences. "Now that it is clear that SC35 binds to a different protein than assumed, previous research results on nuclear speckles must be carefully reevaluated," says Akta.The antibody SC35 has also been widely used in disease research, since the speckles have been implicated in several neurodegenerative conditions such as Huntington's disease, spinocerebellar ataxia and dentatorubro-pallidoluysis atrophy. "There may be entirely new perspectives for research into these diseases," says Akta.
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Zoology
| 2,020 |
November 27, 2020
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https://www.sciencedaily.com/releases/2020/11/201127085456.htm
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Study of threatened desert tortoises offers new conservation strategy
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In Nevada's dry Ivanpah Valley, just southeast of Las Vegas, a massive unintended experiment in animal conservation has revealed an unexpected result.
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From 1997 to 2014, the U.S. Fish and Wildlife Service moved more than 9,100 Mojave desert tortoises to the 100-square-kilometer (about 39 miles square) Large Scale Translocation Site. The newcomers, many of which were abandoned pets or had been displaced by development, joined nearly 1,500 desert tortoises already living there.Conventional wisdom would suggest that tortoises from areas closest to the translocation site would fare best. But a new UCLA study, published today in Tortoises with lots of genetic variation were much more likely to survive after their relocation, said UCLA conservation ecologist Brad Shaffer, the study's senior author. Like most organisms, tortoises have two copies of their entire genome, with one copy from each parent. The more those copies differ from each other, the higher the organism's heterozygosity.The researchers compared translocated tortoises that lived or died over the same time period after being relocated to the site. They found that survivors averaged 23% greater heterozygosity than those that perished. Simply put, tortoises with more genetic variation had higher survival rates."It flies in the face of what we know from other translocation studies, but lots of genetic variation was hands-down the best predictor of whether a tortoise lived or died," said Shaffer, a professor of ecology and evolutionary biology and director of the UCLA La Kretz Center for California Conservation Science. "Relocating endangered plants and animals is increasingly necessary to counteract the effects of climate change, and this gives us a new tool to increase survival rates."Although the relationship between heterozygosity and survival was well supported by the study, it's unclear why greater genetic variation is linked to survival rates, said former UCLA postdoctoral scholar Peter Scott, the study's lead author."Potentially, individuals with higher heterozygosity have more genomic flexibility," said Scott, who is now an assistant professor at West Texas A&M University. "It's likely that tortoises with more variation have a better chance of having one copy of a gene that works really well in stressful or new environments compared to those individuals with two identical copies that only work really well in their environment of origin."The researchers wanted to make tortoise conservation efforts more effective, and uncover trends that would help other species as well, Scott said."Oftentimes, the chances of success for relocating plants or animals is pretty dismal," he said. "We wanted to understand why, and use that understanding to increase survival."Over the years, tortoises that were given up as pets, or removed from places like developments in suburban Las Vegas and solar farms in the desert, were surrendered to the U.S. Fish and Wildlife Service.The agency took blood samples to screen for diseases and marked each animal before releasing them into the Ivanpah Valley site, which enabled the animals to be tracked in later surveys. The UCLA researchers sequenced blood samples drawn from 79 tortoises that were released to the site and were known to be alive in 2015, and from another 87 known to have died after they were released at the site.Although the Large Scale Translocation Site provided an intriguing dataset, it's not the same as a controlled experiment. Additional studies would be needed to understand why more heterozygous tortoises had a higher survival probability and precisely how much of an increase in genetic variation improves a tortoise's odds of surviving."The only reason we could do this study was because the U.S. Fish and Wildlife Service was incredibly forward-thinking when they set up the translocation site and tracked who lived and died," Shaffer said. "Many died, and no one was happy about that. But we can learn a lot from that unfortunate result to help conservation management improve."When thinking about moving animals or plants out of danger, or repopulating an area emptied by wildfire, now we can easily and economically measure genetic variability to better gauge the survival probability of those translocated individuals. It's not the only criteria, but it's an important piece of the puzzle."
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Zoology
| 2,020 |
November 26, 2020
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https://www.sciencedaily.com/releases/2020/11/201124111332.htm
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Only dinosaurs found in ireland described for the first time
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The only dinosaur bones ever found on the island of Ireland have been formally confirmed for the first time by a team of experts from the University of Portsmouth and Queen's University Belfast, led by Dr Mike Simms, a curator and palaeontologist at National Museums NI.
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The two fossil bones were found by the late Roger Byrne, a schoolteacher and fossil collector, who donated them along with many other fossils to Ulster Museum. Analysis has confirmed they are from early Jurassic rocks found in Islandmagee, on the east coast of County Antrim.Ulster Museum has announced plans to put them on display when it reopens after the latest rounds of restrictions are lifted.Dr Simms, National Museums NI, said: "This is a hugely significant discovery. The great rarity of such fossils here is because most of Ireland's rocks are the wrong age for dinosaurs, either too old or too young, making it nearly impossible to confirm dinosaurs existed on these shores. The two dinosaur fossils that Roger Byrne found were perhaps swept out to sea, alive or dead, sinking to the Jurassic seabed where they were buried and fossilised."The article, published in the Originally it was assumed the fossils were from the same animal, but the team were surprised to discover that they were from two completely different dinosaurs. The study, employing the latest available technology, identified the type of dinosaur from which each came. One is part of a femur (upper leg bone) of a four-legged plant-eater called Scelidosaurus. The other is part of the tibia (lower leg bone) of a two-legged meat-eater similar to Sarcosaurus.The University of Portsmouth team, researcher Robert Smyth, originally from Ballymoney, and Professor David Martill, used high-resolution 3D digital models of the fossils, produced by Dr Patrick Collins of Queen's University Belfast, in their analysis of the bone fragments.Robert Smyth said: "Analysing the shape and internal structure of the bones, we realised that they belonged to two very different animals. One is very dense and robust, typical of an armoured plant-eater. The other is slender, with thin bone walls and characteristics found only in fast-moving two-legged predatory dinosaurs called theropods.""Despite being fragmentary, these fossils provide valuable insight on a very important period in dinosaur evolution, about 200 million years ago. It's at this time that dinosaurs really start to dominate the world's terrestrial ecosystems."Professor Martill said: "Scelidosaurus keeps on turning up in marine strata, and I am beginning to think that it may have been a coastal animal, perhaps even eating seaweed like marine iguanas do today."To find out when the fossils will go on display at the Ulster Museum follow @ulstermuseum on Twitter, @ulstermuseumbelfast on Facebook and @ulstermuseum on Instagram.
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Zoology
| 2,020 |
November 25, 2020
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https://www.sciencedaily.com/releases/2020/11/201125091525.htm
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New plant-based gel to fast-track 'mini-organs' growth, improve cancer treatment
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- Monash University researchers have created the world's first bioactive plant-based nanocellulose hydrogel to support organoid growth for biomedical applications. This includes cancer development and treatment.
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Monash University researchers have created the world's first bioactive plant-based nanocellulose hydrogel to support organoid growth and help significantly reduce the costs of studies into cancer and COVID-19.This discovery by researchers at BioPRIA (Bioresource Processing Institute of Australia), Monash University's Department of Chemical Engineering and the Monash Biomedicine Discovery Institute will develop organoids cheaper, faster and more ethically.The hydrogel can also improve drug screening and disease modelling for infectious diseases, like COVID-19; metabolic diseases, such as obesity and diabetes; and cancer.The findings, published in Nanocellulose gels cost just cents for every 10ml used, compared to $600 or more for the current gold standard.Above all, nanocellulose gels are completely plant-based, preventing the harvesting of animal organs and unknown biomolecules for any advanced medical testing.Professor Gil Garnier and Dr Rodrigo Curvello from BioPRIA within Monash University's Department of Chemical Engineering led the study."Organoids provide a robust model for key applications in biomedicine, including drug screening and disease modelling. But current approaches remain expensive, biochemically variable and undefined," Professor Garnier, Director of BioPRIA, said."These are major obstacles for fundamental research studies and the translation of organoids to clinics. Alternative matrices able to sustain organoid systems are required to reduce costs drastically and to eliminate the unreliability of unknown biomolecules."As nanocellulose hydrogel is animal-free, its composition is controlled perfectly and reproducible -- unlike the current progress -- and fully mimic the human body conditions."Organoids are three-dimensional, miniaturised and simplified versions of organs produced in vitro that can replicate behaviours and functionalities of developed organs.Commonly referred to as 'organs in a dish' or 'mini-organs', organoids are an excellent tool to study basic biological processes. Through organoids, we can understand how cells interact in an organ, how diseases affect them and the effects of drugs in disease reduction.Organoids are generated from embryonic, adult, pluripotent or induced pluripotent stem cells, as well as from primary healthy or cancerous tissues. For long-term use, organoids are commonly embedded within an Engelbreth-Holm Swarm (EHS) matrix derived from the reconstituted basement membrane of mouse sarcoma.Currently, organoid culture is dependent of this expensive and undefined tumour-derived material that hinders its application in high-throughput screening, regenerative medicine and diagnostics."Our study was essentially able to use an engineered plant-based nanocellulose hydrogel that can replicate the growth of small intestinal organoids derived from mice," Dr Curvello said."It is essentially made from 99.9% water and only 0.1% solids, functionalised with a single cell adhesive peptide. Cellulose nanofibers are linked with salts that provide the microenvironment needed for small intestinal organoid growth and proliferation."Engineered nanocellulose gel represents a sustainable alternative for the growth of organoids, contributing to reducing the costs of studies on diseases of global concern, particularly in developing countries."
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Zoology
| 2,020 |
November 23, 2020
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https://www.sciencedaily.com/releases/2020/11/201123112504.htm
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How moving slower allows groups of bacteria to spread across surfaces
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Scientists have found that bacterial groups spread more rapidly over surfaces when the individuals inside them move slowly, a discovery that may shed light on how bacteria spread within the body during infections.
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Researchers from the University of Sheffield and the University of Oxford studied Pseudomonas aeruginosa, a species of bacteria responsible for deadly lung infections, which moves across surfaces using tiny grappling hook-like appendages called pili. Similar to the fable of the tortoise and the hare, they found that bacteria engineered to individually move faster actually lost the race against slower strains when moving in densely packed groups.Using a combination of genetics, mathematics, and sophisticated tracking algorithms that can simultaneously follow the movement of tens of thousands of cells, the researchers demonstrated that collisions between the fast-moving bacteria cause them to rotate vertically and get stuck.In contrast, slower-moving cells remain lying down, allowing them to keep moving. The slower-moving cells therefore win the race into new territory, acquire more nutrients, and ultimately outcompete the faster moving cells. This research suggests that bacteria have evolved slow, restrained movement to benefit the group as a whole, rather than individual cells.The findings have been published in the journal Dr William Durham, a Lecturer in Biological Physics at the University of Sheffield, said: "We routinely experience gridlock in our own lives while traveling by foot or in cars. These traffic jams often occur because individuals have prioritised their own movement over that of their neighbours. In contrast, bacteria have evolved to move carefully and effectively in crowds, likely because their neighbours tend to be genetically identical, so there is no conflict of interest. Bacteria accomplish this by moving more slowly than their top speed."To understand these phenomena, the researchers used a theory that was originally developed to study materials known as liquid crystals.Dr Oliver Meacock, a postdoctoral researcher at the University of Sheffield and lead author of the study, said: "Liquid crystals are everywhere around us, from smartphone screens to mood rings. Although we initially didn't expect that the mathematical tools developed to understand these human-made materials could be applied to living systems, our findings show that they can also shed light on the challenges faced by microbes."Patterns of collective movement that occur in flocks of birds and schools of fish have long been a source of fascination to onlookers. This new research shows that similarly spectacular forms of collective movement also occur in the microscopic world.
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Zoology
| 2,020 |
November 23, 2020
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https://www.sciencedaily.com/releases/2020/11/201123085322.htm
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Identical evolution of isolated organisms
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Palaeontologists at Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) and the University of Calgary in Canada have provided new proof of parallel evolution: conodonts, early vertebrates from the Permian period, adapted to new habitats in almost identical ways despite living in different geographical regions. The researchers were able to prove that this was the case using fossil teeth found in different geographical locations.
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One of the most convincing arguments proving the theory of evolution is that it is fairly easy to predict how animals and plants will evolve to adapt to changes in their habitats. There is no shortage of proof that organisms with a common ancestor evolve in the same way even if they are entirely isolated from each other. One of the most prominent examples is the Midas cichlid in Nicaragua. Approximately 6,000 years ago, individual fish colonised various crater lakes. Interestingly, they developed identical morphologies in their new habitats. One group specialised in catching small shrimps and developed a stocky body with a flat mouth. Another group hunts fish in deeper water and is considerably more streamlined. 'These subspecies are found in each of the crater lakes, although there is no connection whatsoever between the habitats,' says Dr. Emilia Jarochowska from GeoZentrum Nordbayern at FAU. 'This is an example of parallel evolution.'Emilia Jarochowska's research focuses on evolution in different ecosystems, but rather than studying animals which are still alive today she concentrates on conodonts, organisms which lived in the sea approximately 500 to 200 million years ago and were one of the first vertebrates. The cone-shaped teeth of the eel-like organisms can still be found as micro fossils in sedimentary rocks across the globe. Scientists estimate that there were roughly 3000 different species of conodonts. 'Scientists have suspected for several years now that a certain subspecies known as Conodont Sweetognathus developed several parallel evolutionary adaptations,' says Emilia Jarochowska.The researchers from Erlangen set out with palaeontologists from the University of Calgary to prove this theory. The Canadian researchers had collected fossilised Sweetognathus teeth from various locations across the world, including Bolivia and Russia. Emilia Jarochowska explains, 'As we now have such a good knowledge of tectonics over the history of the Earth, we can rule out the possibility that organisms from these regions were ever in contact with each other.' The fossils measuring a mere two to three millimetres in length were scanned at GeoZentrum Nordbayern in a scanner with a spatial resolution of four micrometres, which delivers even higher definition pictures than a CT in a hospital. Precise 3D models and mathematical descriptions were made of more than 40 samples.The painstaking analysis of the morphologies in the dental elements confirmed what scientists have suspected for years: Conodont Sweetognathus adapted repeatedly in response to different food sources after emigrating to new habitats in an almost identical fashion in spite of these habitats being isolated from each other. Comparing samples from a large number of fossils over a number of years has now allowed researchers to confirm without a doubt that the teeth found in Bolivia and Russia come from organisms with a common ancestor. 'We were able to prove that two lineages of Sweetognathus in two different parts of the world followed the same developmental pattern,' Emilia Jarochowska explains. 'That is further proof for the theory of evolution -- and for the effectiveness of international collaboration.'
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Zoology
| 2,020 |
November 20, 2020
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https://www.sciencedaily.com/releases/2020/11/201120091142.htm
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Alternative gene control mechanism based on organization of DNA within nucleus
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Researchers at the University of Tokyo have identified how the architecture of the cell nucleus can change gene activity in plants. This discovery reveals fundamental knowledge about genome regulation and points towards future methods for potentially manipulating the expression of many genes simultaneously.
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The long strands of DNA and the protein machinery needed to turn gene expression on or off are contained, floating within the nuclei of cells. The nucleus is essentially a sack made of a flexible, double-membrane envelope that is supported by an inner, fine-mesh frame of proteins called the nuclear lamina."DNA does not drift aimlessly within the nucleus. We expect that there is nonrandom spatial positioning of genes around the nuclear lamina," said Professor Sachihiro Matsunaga who led the research project from the University of Tokyo Graduate School of Frontier Sciences, recently published in Gene regulation is often studied at the one-dimensional level of reading the DNA sequence. Additional layers of gene regulation exist in 3D by changing the shape of the DNA strand. Examples include the epigenetic code that dictates how tightly to wind up the strands of DNA and the phenomenon of "kissing genes," where distant segments of the DNA strand fold together and change the activity of the genes that touch each other.These new results provide evidence for another 3D method of gene regulation involving not just the architecture of the genome, but the architecture of its container, the nucleus.The scientific community has long known that the shape and size of the nucleus can fluctuate dramatically during a cell's life and that these changes can even be timed as an "internal clock" to determine the age of a cell. However, these discoveries have been made using animal cells. Plants do not possess any genes evolutionarily related to the genes responsible for the nuclear lamina in animals."Textbooks usually have a few sentences about animal lamina, but nothing at all to say about plant lamina," said Matsunaga.Prior work in 2013 by some members of the research team identified a group of four proteins known as CROWDED NUCLEI (CRWN) as the most likely components of the plant nuclear lamina.To confirm the presence of CRWN proteins in the lamina, researchers first attached fluorescent tags onto the proteins and isolated nuclei out of root cells from young thale cress plants, the roadside weed commonly used in research labs. Then they measured the proteins' location in ultrahigh-resolution microscopy images.These extremely zoomed-in images show weblike patterns formed by the CRWN proteins around the shell of the nucleus.Healthy plant cells have an oval-shaped nucleus, looking like a large egg in the center of the cell. Plants genetically altered to lack CRWN proteins have nuclei that are smaller and rounder than normal, likely creating a more crowded environment for the DNA inside.Researchers then screened the genetically altered plants to see if any other genes had different activity levels when crwn genes were inhibited. Multiple genes known to be involved in responding to copper were less active, indicating that somehow the nuclear lamina is connected to copper tolerance.Plants that lack CRWN proteins grow shorter than healthy plants even in normal soil. Thale cress with inactive crwn genes planted in soil with high copper levels grew even smaller with a significantly weaker appearance, further evidence that the nuclear lamina has a role in plants' response to environmental stress.Researchers also visualized the physical location of copper tolerance genes within the nucleus of both normal and high copper levels. In healthy plants in the high copper condition, the copper tolerance genes clustered together and moved even closer to the periphery of the nucleus. The copper tolerance genes appeared to spread out and drift around the nuclei in plants with inactive crwn genes."If the plant nucleus has distinct regions for active transcription of DNA, it is likely that those regions will be near the nuclear lamina. This is important and interesting because it is opposite to animal cells, which we know have active regions in the center of nuclei while the periphery is inactive," said Matsunaga.Most gene editing technologies to increase or decrease gene activity work directly at the one-dimensional level of altering the DNA sequence of the individual gene. Understanding how the nuclear lamina affects gene expression could reveal future methods for altering the activity of many genes at the same time by resculpting the genome and nuclear lamina.
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Zoology
| 2,020 |
November 20, 2020
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https://www.sciencedaily.com/releases/2020/11/201118141900.htm
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Sexual lineage plays key role in transgenerational plasticity
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A new pair of papers published in the
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Bell's research group is interested in how experience (nurture) and genetic information (nature) merge to influence how animals develop and behave. Between parents and offspring, this can happen through transgenerational plasticity, when parental environments alter future generations.Dr. Jennifer Hellmann (assistant professor, University of Dayton, former postdoctoral researcher in the Bell lab) led the study, which examined how maternal versus paternal exposure to the same environmental condition can have different effects on offspring and future generations.In the first paper of the study, researchers exposed mothers, fathers or both parents to visual cues of predation risk. The team then measured the offspring antipredator traits and brain gene expression in the offspring. Stickleback fish typically have paternal care, and previous research in the Bell lab found that a predator-exposed father will change his behavior towards his offspring. However, in this study the stickleback offspring were separated from their father, meaning that subsequent behavioral differences were due only what the offspring inherited from their father through sperm."Originally, we thought that there would be sex specific effects," said Alison Bell, professor of evolution, ecology and behavior and co-author of the study. "Sons would be more impacted (than daughters) by what happened to their fathers. That's not what we found at all."Results from the study showed that predator-exposed fathers produced sons that were more risk-prone, whereas predator-exposed mothers produced more anxious sons and daughters. In addition, the ways in which daughters and sons were impacted by the same inherited exposure were different. "If you scare a mother, those changes look different than if you had scared a father," said Bell. "Different traits are affected. The sex of the parent matters and the sex of the offspring matters."In the second paper of the study, the researchers tested one generation further to see how long these brain gene expression and behavioral trait changes persisted. Given what researchers had previously found about sex-dependent inheritance, they once again tracked the sex lineage of which now-grandparent(s) were exposed. "We were evaluating four different groups through maternal, paternal, both or neither grandfather exposed, which was an incredible amount of work -- but these effects are clearly sex-dependent and we wanted to understand that further," said Bell. "How many generations will have this effect persist, and how does the grandparent source of the change matter?"Here again, the researchers' results were surprising. Findings suggested unique patterns of inheritance -- for example, predator-exposed fathers would impact their daughters, who would produce grandsons that were affected by their maternal grandfather's exposure. Along another inheritance line -- exposed grandfather to son to granddaughters, for example -- those exposure impacts would look different."So sex and where these traits came from matters," explained Bell. "Fathers don't just contribute DNA in their sperm, they're also passing down information about their environment in their sperm. Both parents are passing down this kind of environmental information, and what those changes look like depends on sex every step of the way -- grandparent, parent, and offspring."This study is one of the most careful to date examining the sex lineage in transgenerational plasticity, and was supported by a Postdoctoral National Research Service Award from the National Institutes of Health to Hellmann, NIH and the School of Integrative Biology.
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Zoology
| 2,020 |
November 19, 2020
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https://www.sciencedaily.com/releases/2020/11/201119131030.htm
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Understanding lung infections in patients with cystic fibrosis
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For young people with cystic fibrosis, lung infection with
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Previous research models have often looked at To see if they could find a better way to mimic human CF lungs, and decrease the use of animal testing, the researchers used pig lungs from a butcher, and adding synthetic CF mucus. They then introduced the Due to the lack of knowledge of how Dr Esther Sweeney, from the School of Life Sciences at the University of Warwick comments:"The model we have used with pig lung has shown that S.aureus preferentially grows within mucus. We think this potentially represents the clinical situation for people with CF better than historical research models and our model could be used to further investigate the best ways of treating MRSA infection associated with cystic fibrosis. In future this may help to reduce inappropriate use of antibiotics."Dr Freya Harrison, from the School of Life Sciences at the University of Warwick adds:"Knowing how exactly how the lungs are affected by different bacteria is key to treating infection efficiently. We need to know which bacteria do the most damage, and how best to target them to get rid of them. We decided to make a new model using a pig lung, rather than mice, because pig lungs are more similar to human lungs, and we can combine them with artificial CF mucus. We think this makes bacteria behave more like they would in the lungs of a person with CF."
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Zoology
| 2,020 |
November 19, 2020
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https://www.sciencedaily.com/releases/2020/11/201119103101.htm
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Bacteria convince their squid host to create a less hostile work environment
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Bacteria living symbiotically within the Hawaiian bobtail squid can direct the host squid to change its normal gene-expression program to make a more inviting home, according to a new study published in
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Nearly every organism and environment hosts a collection of symbiotic microbes -- a microbiome -- which are an integral component of ecological and human health. In bacteria, small RNA (sRNA) is a key element influencing gene expression in the microscopic organisms, however, there has been little evidence that beneficial bacteria use these molecules to communicate with their animal hosts.In the new study, lead author Silvia Moriano-Gutierrez, a postdoctoral fellow in the Pacific Biosciences Research Center at SOEST, and co-authors found a specific bacterial sRNA that is typically responsible for quality control of the production of protein in the bacterium plays an essential role in the symbiosis between Vibrio fischeri and the squid.The Hawaiian bobtail squid recruits V. fischeri to inhabit the squid's light-organ, as the bacterium are luminescent and camouflage the squid during its nighttime hunting.Through RNA-sequencing, the scientists found in squid's blood sRNA sequences that were produced by bacteria inhabiting the light-organ and found a high concentration of a specific sRNA within the host cells lining the crypts where the bacteria live."The presence of this particular sRNA results in a 'calming' the immune reaction of the squid, which will increase the opportunity for the bacteria to persistently colonize the host tissue, and deliver their beneficial effects," said Dr. Moriano-Gutierrez. "This work reveals the potential for a bacterial symbiont's sRNAs not only to control its own activities but also to trigger critical responses that promote a peaceful partnership with its host."The researchers, including co-author and UH Manoa undergraduate Leo Wu, determined the bacteria load sRNA into their outer membrane vesicles, which are transported into the cells surrounding the symbiont population in the light organ -- decreasing the squid's antimicrobial activities in just the right location."It was unexpected to find a common bacterial sRNA that had evolved for a house-keeping function in the bacterium to be specifically recruited into a bacterium-host communication during the initiation of symbiosis," said Dr. Moriano-Gutierrez."We anticipate that a host's recognition and response to specific symbiont sRNAs will emerge as a major new mode of communication between bacteria and the animal tissues they inhabit," said Dr. Moriano-Gutierrez. "Other symbiont RNAs that get into host cells remain to be explored."
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Zoology
| 2,020 |
November 18, 2020
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https://www.sciencedaily.com/releases/2020/11/201118080745.htm
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Review examines sexual aggression in mammals
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A recent review of published studies in non-human mammals examines "sexual disturbance," or male behavior towards a female around mating that can be costly for the female -- for example, that might inflict physical harm or cause mother-offspring separation. The findings are published in
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The author, Marcelo H. Cassini, PhD, of the Laboratorio de Biología del Comportamiento, in Argentina, found that sexual disturbance was frequent in 4 of the 32 mammalian orders examined: Primates, Artiodactyla, Carnivora, and Cetacea, which all include species with polygyny (in which a male mates with multiple females). The most common response of females to sexual disturbance was grouping around a dominant male.The most common expression of sexual conflict around copulation was seen in behaviors associated with female retention attempts that cause minor harm. Research suggests that the most common response of females to sexual disturbance comprises female grouping around a dominant male.Additional research is needed to see whether sexual disturbance affects the reproductive success of males and females."This review suggests that sexual aggression is a rare behavior among the thousands of species of mammals," Dr. Cassini said.
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Zoology
| 2,020 |
November 17, 2020
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https://www.sciencedaily.com/releases/2020/11/201117085936.htm
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Spiny dogfish eat Atlantic cod: DNA may provide some answers
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Conventional observations show that spiny dogfish in the western North Atlantic rarely eat Atlantic cod. However, some believe the rebuilding dogfish populations are limiting depleted cod numbers by competition or predation. To find out what is going on, NOAA Fisheries scientists looked to genetic testing to confirm cod presence in dogfish stomachs.
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To get the samples they needed, scientists at the Northeast Fisheries Science Center asked local fishermen for help. Commercial fishing boats from New Bedford, Gloucester, Plymouth and Newburyport in Massachusetts stepped up. All participate in the Study Fleet, a program in the center's Cooperative Research Branch. Spiny dogfish were collected on 15 fishing trips during normal trawling operations between May 2014 and May 2015 in the Gulf of Maine and on Georges Bank."This was an excellent example of how cooperating fishing partners supplied fish for a pilot study of interest, and have helped advance this field of study," said Richard McBride, chief of the center's Population Biology Branch and a co-author of the study. "We were able to demonstrate that identifying cod in predator stomachs with environmental DNA works. It let us show fishermen that these innovative laboratory techniques can work on samples collected in the open ocean."Study findings, published in Dogfish primarily eat other fish, but also jellyfish, squid and bivalves in some locations. Cod as dogfish prey is rare. Only 14 cod have been visually observed in the stomachs of 72,241 dogfish collected by the science center's bottom trawl surveys from 1977 to 2017. This suggests low predation rates on cod. However, small cod are much more likely to be well-digested when the samples are taken. If dogfish have eaten these smaller cod, it is difficult to identify the species by observation alone. Molecular-level studies, using DNA, offered some answers.In the recently published study, researchers examined the stomach contents of 295 dogfish samples collected throughout the year. Using the conventional visual method, they observed 51 different prey types and nearly 1600 individual prey items. NOAA Fisheries scientists paired these visual observations with a laboratory technique (real-time polymerase chain reaction, or PCR) to detect small amounts of cod DNA. Using this technique, researchers examined 291 of the 295 available samples and detected cod DNA in 31 of them.Fishermen have also reported seeing dogfish eating cod during fishing operations. Sometimes this is dogfish actively foraging on live prey. Other times it is due to dogfish depredation - dogfish eating the fish in the net before it can be brought aboard the fishing vessel. In this study, 50 percent of the sampling trips where cod was eaten indicate scavenging by spiny dogfish.Members of the study fleet who helped collect the samples recognize the value of their participation in the study."It's always good to have more information on the species that live in our waters. I'm happy to contribute to work that furthers our understanding of these populations, especially in regard to cod," said Captain Jim Ford of the F/V Lisa Ann III from Newburyport. "I know there are some different opinions on what role dogfish play in the ecosystem, so the more data we can provide to inform that, the better."While the findings suggest higher interaction rates between dogfish and cod than previously observed, further study is needed to determine just how much cod dogfish eat. Studies are ongoing to better integrate factors such as predator-prey relationships into stock assessment models used to estimate both current and future fish population numbers.Researchers say the next step is to use a statistically robust sampling design to examine a population-level assessment of the effects of dogfish predation on cod population size. Estimates of spiny dogfish digestion rates, and ways to consider dogfish scavenging during fishing operations, are also needed."The Northeast Fisheries Science Center has the laboratory facilities to detect cod DNA in predator stomachs, and a bottom trawl survey that is designed to measure population level effects among groundfish," said McBride. "We just need to put these two pieces together to estimate the effect of spiny dogfish predation on Atlantic cod. Easier said than done, but all the pieces are there."
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Zoology
| 2,020 |
November 12, 2020
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https://www.sciencedaily.com/releases/2020/11/201112144020.htm
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Mimicking SARS-CoV-2 nasal infection in monkeys
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A new rhesus macaque animal model recapitulates the clinical and pathological manifestations of coronavirus disease 2019 (COVID-19) observed in humans by mimicking natural infection via the nasal route, according to a study published November 12 in the open-access journal
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The first step of all effective means to control COVID-19 and develop vaccines is to understand the viral infection process. Toward that goal, an effective animal model of SARS-CoV-2 infection is urgently needed. In the new study, the researchers developed a rhesus macaque model to mimic natural infection via the nasal route. The rhesus macaques displayed similar clinical and pathological manifestations of COVID-19 observed in humans.The results revealed SARS-CoV-2 virus shedding- the release of virus progeny following successful reproduction -- in the nose and stool for up to 27 days. This pattern of long-term viral shedding in rhesus macaques is strikingly similar to that observed in humans. The authors also observed similar pathological changes between humans and rhesus macaques in the progression from mild to marked interstitial pneumonia -- an inflammatory condition affecting the tissue and space around the air sacs of the lungs. The results further revealed immune responses involving T cells, which contributed to the progression of COVID-19, and inflammation-promoting, cell-signaling molecules called inflammatory cytokines in the respiratory tract. The findings suggest that the development of COVID-19 treatments and vaccines should focus not only on viral shedding and interstitial pneumonia, but also T cell responses and cytokine changes in the lungs.The authors conclude that their study of "nasal infection in rhesus monkey revealed the immune response and pathologic process of COVID-19."
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Zoology
| 2,020 |
November 11, 2020
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https://www.sciencedaily.com/releases/2020/11/201111122832.htm
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Scientists release genomes of birds representing nearly all avian families
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Since the first bird evolved more than 150 million years ago, its descendants have adapted to a vast range of ecological niches, giving rise to tiny, hovering hummingbirds, plunge-diving pelicans and showy birds-of-paradise. Today, more than 10,000 species of birds live on the planet -- and now scientists are well on their way to capturing a complete genetic portrait of that diversity.
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In the Nov. 11 issue of the journal Together, the data constitute a rich genomic resource that is now freely available to the scientific community. The release of the new genomes is a major milestone for the Bird 10,000 Genomes Project (B10K), an international collaboration organized by researchers at the Smithsonian's National Museum of Natural History, the Kunming Institute of Zoology, the Institute of Zoology in Beijing, the University of Copenhagen, The Rockefeller University, BGI-Shenzen, Curtin University (Perth), the Howard Hughes Medical Institute, Imperial College London and the Natural History Museum of Denmark, which aims to sequence and share the genome of every avian species on the planet."B10K is probably the single most important project ever conducted in the study of birds," said Gary Graves, curator of birds at the National Museum of Natural History and one of B10K's seven organizers. "We're not only hoping to learn about the phylogenetic relationships among the major branches of the tree of life of birds, but we're providing an enormous amount of comparative data for the study of the evolution of vertebrates and life itself."Comparing genomes across bird families will enable B10K researchers and others to explore how particular traits evolved in different birds, as well as to better understand evolution at the molecular level. Ultimately, B10K researchers aim to build a comprehensive avian tree of life that charts the genetic relationships between all modern birds. Such knowledge will not only reveal birds' evolutionary past but will also be vital in guiding conservation efforts in the future.More than 150 ornithologists, molecular biologists and computer scientists came together to obtain specimens and analyze more than 17 trillion base pairs of DNA for the family-level phase of the B10K project. Sequencing and analysis began in 2011, but the data represent several decades of work by field collectors and collections management staff who have collected and preserved birds from every continent, Graves said.Approximately 40% of the newly sequenced bird genomes were obtained using tissue samples preserved in the National Museum of Natural History's Avian Genetic Resources Collection, which Graves started in 1986 and has since become part of the Smithsonian's Global Genome Initiative biorepository. Also contributing to the project were Michael Braun, a research zoologist at the National Museum of Natural History; Rebecca Dikow, who leads the Smithsonian Data Science Lab; and researchers with the Smithsonian's National Zoo and Conservation Biology Institute and the Smithsonian Tropical Research Institute in Panama."It might seem that having a genome for each bird family or species is a bit like stamp collecting, but this massive cooperative effort has given us a set of very important genomic resources for conservation," said Rob Fleischer, one of the authors and head of the Smithsonian Conservation Biology Institute's Center for Conservation Genomics. "For example, it provides a ready source of genetic markers useful to map population declines, identify kin and reduce inbreeding when managing rescue populations of endangered species. Having the genomes simplifies the search for genes responsible for important survival traits such as resistance to deadly introduced diseases.""Through 34 years of field work and dozens of expeditions, we were able to get the stockpile of high-quality DNA that actually makes this project possible," Graves said. "Many of those resources were stored long before DNA sequencing technology had been developed, preserved for future analyses their collectors could not have imagined at the time. It's one of the many reasons why natural history museum collections and museum-based research programs are so important!"With 363 genomes complete, B10K is expanding its efforts to encompass the next level of avian classification. In this phase, the team will sequence thousands of additional genomes, aiming to represent each of the approximately 2,300 genera of birds.Funding and support for this research were provided by the Smithsonian, China National Genebank, the Chinese Academy of Sciences, the Carlsberg Foundation, the Villum Foundation, the National Natural Science Foundation of China, the European Research Council, the Howard Hughes Medical Institute, the National Institutes of Health, the University of Denmark and Louisiana State University.
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Zoology
| 2,020 |
November 11, 2020
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https://www.sciencedaily.com/releases/2020/11/201111122757.htm
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Prenatal thyroid hormones influence 'biological age' at birth
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The environment provided by the mother during embryo development has major consequences on later-life health and lifespan. This can arise through effects on cellular ageing which is often estimated with the length of telomeres. Telomeres are the protective end caps of chromosomes and their length is a marker of 'biological age'.
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While telomeres normally shorten with age, short telomeres at a given age predict higher disease and mortality risks. Prenatal exposure to maternal stress hormones as well as instability during embryo development have previously been found to result in short telomeres, i.e. accelerated cellular ageing.A new study funded by the Academy of Finland and the Turku Collegium for Science and Medicine manipulated prenatal exposure to maternal thyroid hormones using egg injection in an avian model."The telomere biology of humans is closer to the telomere biology of birds than those of traditional laboratory models. In both human and birds, telomere length is measured in a minimally-invasive way from small blood samples," says Collegium Researcher Antoine Stier from the University of Turku (Finland), the main author of the research article.While authors of the study had reasons to expect shorter telomeres in chicks born from eggs injected with thyroid hormones, they were quite surprised to find that those chicks actually exhibited longer telomeres right after birth."Based on the natural decline of telomere length observed with age in the same collared flycatcher population, we estimated that chicks hatching from thyroid hormones injected eggs were approximately 4 years 'younger at birth' than chicks hatched from control eggs," adds Collegium Researcher Suvi Ruuskanen.Although the molecular mechanisms underlying such effects remain to be discovered, the new findings suggest that prenatal thyroid hormones might have a role in setting the 'biological age' at birth."Considering the interest and controversies surrounding gene therapy trials in humans to elongate telomeres as an anti-ageing therapy, this discovery opens potential avenues to better understand the influence of telomere elongation in animal models," Stier says.The study was conducted on a long-term monitored population of wild collared flycatcher breeding in Gotland island, and relied on extensive collaborations with the University of Uppsala (Sweden), Lyon, Glasgow and Aberdeen.
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Zoology
| 2,020 |
November 10, 2020
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https://www.sciencedaily.com/releases/2020/11/201110133143.htm
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Group size and makeup affect how social birds move together
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Scientists have shown that the size and makeup of groups of social birds can predict how efficiently they use and move through their habitat, according to new findings published today in
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The study suggests that intermediate-sized groups of vulturine guineafowl -- a ground-dwelling social bird found in east African savannahs -- exhibit the most effective balance between a decreased ability to coordinate movements and increased accuracy of navigation.These findings add to our understanding of a key question in animal sociality -- namely, whether groups have an optimal size -- by showing that the number of individuals in a group determines the ability of that group to make the most effective use of their environment."For many social animals, larger groups benefit from information pooling, where inputs from multiple individuals allow for more accurate decisions about navigation," explains first author Danai Papageorgiou, IMPRS Doctoral Student at the Department of Collective Behaviour, Max Planck Institute of Animal Behavior, and at the Centre for the Advanced Study of Collective Behaviour, University of Konstanz, Germany. "However, as groups become larger they start to face challenges in coordinating their actions, such as reaching a consensus about where to go next or maintaining cohesion as they move through vegetation."Papageorgiou and her PhD advisor, Professor Damien Farine, investigated the relationship between the size and collective movement of groups of vulturine guineafowl. They predicted that the optimal group size of these birds would be determined by the balance between their ability to coordinate movement and their ability to make accurate decisions when navigating.The team fitted individual birds from 21 distinct social groups with GPS tags and collected movement data over five two-month-long seasons. They used these data to calculate the groups' habitat use, including their home-range size, the distance that they travelled each day and their movement speed while 'on the go'. By observing the groups each week, they could also measure the size of each group and record their makeup. Specifically, they recorded the number of chicks in each group, as they predicted that the birds' movement abilities may be restricted when there are more chicks because they are slower and much more vulnerable to predators.The researchers found that intermediate-sized groups, consisting of 33-37 birds, ranged over larger areas and achieved this by travelling shorter distances each day, compared to smaller and larger groups. They also explored the most new areas. These results suggest that intermediate-sized groups were more efficient in using the space, potentially encountering more resources while spending less energy and lowering their chances of being tracked by predators. Additionally, data collected on the birds' reproductive success reinforced the fact that intermediate-sized groups benefited from these movement characteristics, as they also had more chicks.However, the study also found interesting consequences of having a beneficial group size for movements. Groups with many chicks, despite being the optimal size, had more restricted home ranges. This was likely because the chicks needed more protection from predators, and therefore stayed in the protected vegetation for longer periods of time, and their small sizes slowed down the group while moving.As a result, the study showed that intermediate-sized groups were in fact rarer than smaller and larger groups. Papageorgiou and Farine suggest this is because the benefits of being in an optimal-sized group makes the size of these groups less stable. For example, higher reproductive success inevitably pushes the group past its optimal group size."Our study highlights how all groups are not equal, with the effects of group size and composition playing a major role in shaping how social species use their habitat," Farine says. "What is particularly interesting is that optimally sized groups are not expected to be common. Future studies should investigate whether these relationships change across different environmental conditions, and how animal groups cope with the different challenges that each season brings."
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Zoology
| 2,020 |
November 10, 2020
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https://www.sciencedaily.com/releases/2020/11/201110102527.htm
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Fish give insight on sound sensitivity in autism
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A tiny fish is helping scientists understand how the human brain processes sound, while also giving insight to autism spectrum disorder.
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Queensland Brain Institute's Associate Professor Ethan Scott and Dr Lena Constantin used zebrafish that carry the same genetic mutations as humans with Fragile X syndrome and autism, and discovered the neural networks and pathways that produce the hypersensitivities to sound in both species."Loud noises often cause sensory overload and anxiety in people with autism and Fragile X syndrome -- sensitivity to sound is common to both conditions," Dr Constantin said."We think the brain is transmitting more auditory information because it is being filtered and adjusted differently."Half of males and one fifth of females with Fragile X syndrome also meet the diagnostic criteria for autism spectrum disorder."Dr Gilles Vanwalleghem and Rebecca Poulsen were part of the team that studied how zebrafish make sense of their world, in order to explore how neurons work together to process information."Fragile X syndrome is caused by the disruption of one gene, so we can disrupt that single gene in zebrafish and see the effects," Dr Vanwalleghem said."We are able to study the whole brain of the zebrafish larvae under the microscope and see the activity of each brain cell individually."Dr Constantin said the team recorded the brain activity of zebrafish larvae whilst showing them movies or exposing them to bursts of sound."The movies simulate movement or predators -- the reaction to these visual stimuli was the same for fish with Fragile X mutations, and those without," Dr Constantin said."But when we gave the fish a burst of white noise, there was a dramatic difference in the brain activity in Fragile X model fish."After seeing how the noise radically affected the fish brain, the team designed a range of 12 different volumes of sound and found the Fragile X model fish could hear much quieter volumes than the control fish."The fish with Fragile X mutations had more connections between different regions of their brain and their responses to the sounds were more plentiful in the hindbrain and thalamus," Dr Constantin said.She said the thalamus worked as a control centre, relaying sensory information from around the body to different parts of the brain, while the hindbrain co-ordinated behavioural responses."How our neural pathways develop and respond to the stimulation of our senses gives us insights into which parts of the brain are used and how sensory information is processed," Dr Constantin said."Using the zebrafish, we've been able to see a lot more detail and for the first time, seen more activity in the hindbrain which we're keen to explore further."We hope that by discovering fundamental information about how the brain processes sound, we will gain further insights into the sensory challenges faced by people with Fragile X syndrome and autism."This research was published in
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Zoology
| 2,020 |
November 10, 2020
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https://www.sciencedaily.com/releases/2020/11/201110102524.htm
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Scientists develop AI-powered 'electronic nose' to sniff out meat freshness
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A team of scientists led by Nanyang Technological University, Singapore (NTU Singapore) has invented an artificial olfactory system that mimics the mammalian nose to assess the freshness of meat accurately.
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The 'electronic nose' (e-nose) comprises a 'barcode' that changes colour over time in reaction to the gases produced by meat as it decays, and a barcode 'reader' in the form of a smartphone app powered by artificial intelligence (AI). The e-nose has been trained to recognise and predict meat freshness from a large library of barcode colours.When tested on commercially packaged chicken, fish and beef meat samples that were left to age, the team found that their deep convolutional neural network AI algorithm that powers the e-nose predicted the freshness of the meats with a 98.5 per cent accuracy. As a comparison, the research team assessed the prediction accuracy of a commonly used algorithm to measure the response of sensors like the barcode used in this e-nose. This type of analysis showed an overall accuracy of 61.7 per cent.The e-nose, described in a paper published in the scientific journal Co-lead author Professor Chen Xiaodong, the Director of Innovative Centre for Flexible Devices at NTU, said: "Our proof-of-concept artificial olfactory system, which we tested in real-life scenarios, can be easily integrated into packaging materials and yields results in a short time without the bulky wiring used for electrical signal collection in some e-noses that were developed recently."These barcodes help consumers to save money by ensuring that they do not discard products that are still fit for consumption, which also helps the environment. The biodegradable and non-toxic nature of the barcodes also means they could be safely applied in all parts of the food supply chain to ensure food freshness."A patent has been filed for this method of real-time monitoring of food freshness, and the team is now working with a Singapore agribusiness company to extend this concept to other types of perishables.The e-nose developed by NTU scientists and their collaborators comprises two elements: a coloured 'barcode' that reacts with gases produced by decaying meat; and a barcode 'reader' that uses AI to interpret the combination of colours on the barcode. To make the e-nose portable, the scientists integrated it into a smartphone app that can yield results in 30 seconds.The e-nose mimics how a mammalian nose works. When gases produced by decaying meat bind to receptors in the mammalian nose, signals are generated and transmitted to the brain. The brain then collects these responses and organises them into patterns, allowing the mammal to identify the odour present as meat ages and rots.In the e-nose, the 20 bars in the barcode act as the receptors. Each bar is made of chitosan (a natural sugar) embedded on a cellulose derivative and loaded with a different type of dye. These dyes react with the gases emitted by decaying meat and change colour in response to the different types and concentrations of gases, resulting in a unique combination of colours that serves as a 'scent fingerprint' for the state of any meat.For instance, the first bar in the barcode contains a yellow dye that is weakly acidic. When exposed to nitrogen-containing compounds produced by decaying meat (called bioamines), this yellow dye changes into blue as the dye reacts with these compounds. The colour intensity changes with an increasing concentration of bioamines as meat decays further.For this study, the scientists first developed a classification system (fresh, less fresh, or spoiled) using an international standard that determines meat freshness. This is done by extracting and measuring the amount of ammonia and two other bioamines found in fish packages wrapped in widely-used transparent PVC (polyvinyl chloride) packaging film and stored at 4°C (39°Fahrenheit) over five days at different intervals.They concurrently monitored the freshness of these fish packages with barcodes glued on the inner side of the PVC film without touching the fish. Images of these barcodes were taken at different intervals over five days.
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Zoology
| 2,020 |
November 9, 2020
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https://www.sciencedaily.com/releases/2020/11/201109184918.htm
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Why do bats fly into walls?
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Bats excel in acoustic perception and detect objects as tiny as mosquitoes using sound waves. Echolocation permits them to calculate the three-dimensional location of both small and large objects, perceiving their shape, size and texture. To this end, a bat's brain processes various acoustic dimensions from the echoes returning from the object such as frequency, spectrum and intensity.
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But sometimes bats collide with large walls even though they detect these walls with their sonar system. Researchers from Tel Aviv University (TAU) have concluded that these collisions do not result from a sensory limitation but rather from an error in acoustic perception.The study was led by Dr. Sasha Danilovich, a former PhD student in the lab of Prof. Yossi Yovel, Head of the Sagol School for Neuroscience and faculty member at the School of Zoology at the George S. Wise Faculty of Life Sciences. Other participants included Dr. Arian Bonman and students Gal Shalev and Aya Goldstein of the Sensory Perception and Cognition Laboratory at the School of Zoology and the Sagol School of Neuroscience. The paper was published on October 26, 2020, in The TAU researchers released dozens of bats in a corridor blocked by objects of different sizes and made of different materials. To their surprise, the researchers discovered that the bats collided with large sponge walls that produce a weak echo as if they did not exist. The bats' behavior suggested that they did this even though they had detected the wall with their sonar system, indicating that the collision did not result from a sensory limitation, but rather from an acoustic misperception.The researchers hypothesize that the unnatural combination of a large object and a weak echo disrupts the bats' sensory perception and causes them to ignore the obstacle, much like people who bump into transparent walls.The researchers then methodically changed the features of the objects along the corridor, varying their size, texture and echo intensity. They concluded that the bats' acoustic perception depends on a coherent, typical correlation of the dimensions with objects in nature -- that a large object should produce a strong echo and a small object a weak echo."By presenting the bats with objects whose acoustic dimensions are not coherent, we were able to mislead them, creating a misconception that caused them to repeatedly try to fly into a wall even though they had identified it with their sonar," Danilovich explains. "The experiment gives us a peek into how the world is perceived by these creatures, whose senses are so unique and different from ours."
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Zoology
| 2,020 |
November 9, 2020
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https://www.sciencedaily.com/releases/2020/11/201109120321.htm
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Half-a-billion year old microfossils may yield new knowledge of animal origins
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When and how did the first animals appear? Science has long sought an answer. Uppsala University researchers and colleagues in Denmark have now jointly found, in Greenland, embryo-like microfossils up to 570 million years old, revealing that organisms of this type were dispersed throughout the world. The study is published in
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"We believe this discovery of ours improves our scope for understanding the period in Earth's history when animals first appeared -- and is likely to prompt many interesting discussions," says Sebastian Willman, the study's first author and a palaeontologist at Uppsala University.The existence of animals on Earth around 540 million years ago (mya) is well substantiated. This was when the event in evolution known as the "Cambrian Explosion" took place. Fossils from a huge number of creatures from the Cambrian period, many of them shelled, exist. The first animals must have evolved earlier still; but there are divergent views in the research community on whether the extant fossils dating back to the Precambrian Era are genuinely classifiable as animals.The new finds from the Portfjeld Formation in the north of Greenland may help to enhance understanding of the origin of animals. In rocks that are 570-560 mya, scientists from Uppsala University, the University of Copenhagen and the Geological Survey of Denmark and Greenland have found microfossils of what might be eggs and animal embryos. These are so well preserved that individual cells, and even intracellular structures, can be studied. The organisms concerned lived in the shallow coastal seas around Greenland during the Ediacaran period, 635-541 mya. The immense variability of microfossils has convinced the researchers that the complexity of life in that period must have been greater than has hitherto been known.Similar finds were uncovered in southern China's Doushantuo Formation, which is nearly 600 million years old, over three decades ago. Since then, researchers have been discussing what kinds of life form the microfossils represented, and some think they are eggs and embryos from primeval animals. The Greenland fossils are somewhat younger than, but largely identical to, those from China.The new discovery means that the researchers can also say that these organisms were spread throughout the world. When they were alive, most continents were spaced out south of the Equator. Greenland lay where the expanse of the Southern Ocean (surrounding Antarctica) is now, and China was roughly at the same latitude as present-day Florida."The vast bedrock, essentially unexplored to date, of the north of Greenland offers opportunities to understand the evolution of the first multicellular organisms, which in turn developed into the first animals that, in their turn, led to us," Sebastian Willman says.
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Zoology
| 2,020 |
November 7, 2020
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https://www.sciencedaily.com/releases/2020/11/201107133927.htm
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Indian fossils support new hypothesis for origin of hoofed mammals
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New research published today in the
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With more than 350 new fossils, the 15-year study pieces together a nearly complete picture of the skeletal anatomy of the Cambaytherium -- an extinct cousin of perissodactyls that lived on the Indian subcontinent almost 55 million years ago.Among the findings includes a sheep-sized animal with moderate running ability and features that were intermediate between specialized perissodactyls and their more generalized mammal forerunners. Comparing its bones with many other living and extinct mammals, revealed that Cambaytherium represents an evolutionary stage more primitive than any known perissodactyl, supporting origin for the group in or near India -- before they dispersed to other continents when the land connection with Asia formed.This new landmark article was selected for publication as a part of the Society of Vertebrate Paleontology Memoir Series, a special yearly publication that provides a more in-depth analysis of the most significant vertebrate fossils.Cambaytherium, first described in 2005, is the most primitive member of an extinct group that branched off just before the evolution of perissodactyls, providing scientists with unique clues to the ancient origins and evolution of the group."The modern orders Artiodactyla (even-toed ungulates), Perissodactyla, and Primates appeared abruptly at the beginning of the Eocene around 56 million years ago across the Northern Hemisphere, but their geographic source has remained a mystery," explained Ken Rose, emeritus professor at Johns Hopkins University and lead author of the study.Prof. Rose became intrigued by a new hypothesis suggesting that perissodactyls may have evolved in isolation in India. Then India was an island continent drifting northwards, but it later collided with the continent of Asia to form a continuous landmass."In 1990, Krause & Maas proposed that these orders might have evolved in India, during its northward drift from Madagascar, dispersing across the northern continents when India collided with Asia."Armed with this new hypothesis, Rose and colleagues obtained funding from The National Geographic Society to explore India for rare fossil-bearing rocks of the correct age that might provide critical evidence for the origin of perissodactyls and other groups of mammals.The first trip to Rajasthan in 2001 had little success, "Although we found only a few fish bones on that trip, the following year our Indian colleague, Rajendra Rana, continued exploring lignite mines to the south and came upon Vastan Mine in Gujarat."This new mine proved much more promising. Rose added: "In 2004 our team was able to return to the mine, where our Belgian collaborator Thierry Smith found the first mammal fossils, including Cambaytherium."Encouraged, the team returned to the mines and collected fossilized bones of Cambaytherium and many other vertebrates, despite challenging conditions."The heat, the constant noise and coal dust in the lignite mines were tough -- basically trying to work hundreds of feet down near the bottom of open-pit lignite mines that are being actively mined 24/7," he said.Through the cumulation of many years of challenging fieldwork, the team can finally shed light on a mammal mystery. Despite the abundance of perissodactyls in the Northern Hemisphere, Cambaytherium suggests that the group likely evolved in isolation in or near India during the Paleocene (66-56 million years ago), before dispersing to other continents when the land connection with Asia formed.
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Zoology
| 2,020 |
November 7, 2020
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https://www.sciencedaily.com/releases/2020/11/201107133925.htm
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Variety in the migratory behavior of blackcaps
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Through a large-scale study with so-called geolocators, researchers led by Miriam Liedvogel of the Max Planck Institute for Evolutionary Biology in Plön, Germany, were able to uncover some of the mysteries surrounding the phenomenon of the blackcap's bird migration.
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Many species of birds have always migrated south in the fall to spend the winter there, including the small blackcap, which often weighs only a few grams and yet covers thousands of kilometers. However, changes in our landscapes and climate change are not leaving migratory birds unaffected. They change their behavior, the destinations of their journey, the time of their departure or even the decision whether to fly away at all. So far, these habits have been studied either experimentally with birds in captivity or by irregular recaptures of ringed birds.A group of international researchers led by Miriam Liedvogel from the Max Planck Institute for Evolutionary Biology in Plön has now for the first time conducted a large-scale study with geolocators. These are ultra-light, tiny devices that are attached to the backs of free-flying birds and record the light intensity with exact time data. After the birds have been caught again, the respective flight route can be calculated exactly. Altogether the scientists could document and analyze the migrations of 100 individual birds.It was already known beforehand that there is a migration divide in Europe: east of this imaginary line, the blackcaps migrate southeast in the fall, and west of this line, they move southwest. Through targeted breeding experiments, it was already successfully shown in the 1990s that the direction of migration is inherited by the parents. These experiments also showed that offspring crossed in captivity between western- and easterly blackcaps show an intermediate orientation, i.e. they migrate exactly in the direction of the south. The assumption was that this would be avoided in nature, since the southern route would lead the birds over the Alps, the Mediterranean and possibly over the Sahara desert.The scientists were now able to show that this intermediate orientation direction does indeed occur in nature and that the birds that choose this migratory direction also successfully return to their breeding areas despite the ecological barriers they have to overcome in this way. The area in which the orientation preference changes is surprisingly narrow and covers only 27 kilometers.Another exciting finding from the data obtained concerns a group of birds which, at the end of the year, do exactly the opposite of what one would expect: they do not migrate to the warm south but northwards and spend the winter in Great Britain. Since the 1960s, there has been a steady increase in the number of blackcaps that choose this strategy, probably due to milder winters and the winter feeding in English gardens. The new investigations show for the first time that these birds come from brood-areas scattered over whole Europe. Why do they not let themselves be dissuaded from this strategy by uncomfortable winters?On the basis of the evaluated data it was to be recognized that these birds returned in the spring approximately ten days earlier to their breeding places than those which spent the winter in the south. The hibernators from Great Britain possibly had an advantage in the search for breeding places. For the evolutionary scientists, these findings are only a beginning. Bird migration behavior is largely genetic, and this study now lays the groundwork for finding the genes that control where birds migrate and when they fly.
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Zoology
| 2,020 |
November 6, 2020
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https://www.sciencedaily.com/releases/2020/11/201106123313.htm
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Baby dinosaurs were 'little adults'
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Long neck, small head and a live weight of several tons -- with this description you could have tracked down the Plateosaurus in Central Europe about 220 million years ago. Paleontologists at the University of Bonn (Germany) have now described for the first time an almost complete skeleton of a juvenile Plateosaurus and discovered that it looked very similar to its parents even at a young age. The fact that Plateosaurus showed a largely fully developed morphology at an early age could have important implications for how the young animals lived and moved around. The young Plateosaurus, nicknamed "Fabian," was discovered in 2015 at the Frick fossil site in Switzerland and is exhibited in the local dinosaur museum.
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The study was published in the journal In order to study the appearance of dinosaurs more closely, researchers today rely on a large number of skeletons in so-called bone beds, which are places where the animals sank into the mud in large numbers during their lifetime. However, juvenile animals had hardly been found in these until now. Researchers described fossils of still juvenile plateosaurs for the first time just a few years ago, but these were already almost as large as the adults. One possible reason: "The smaller individuals probably did not sink into the mud quite as easily and are therefore underrepresented at the bone beds," suspects study leader Prof. Martin Sander of the University of Bonn.He and his team used comparative anatomy to examine the new skeleton, which was immediately remarkable because of its small size. "Based on the length of the vertebrae, we estimate the total length of the individual to be about 7.5 feet (2.3 meters), with a weight of about 90 to 130 lbs. (40 to 60 kilograms)," explains Darius Nau, who was allowed to examine the find for his bachelor's thesis. For comparison: Adult Plateosaurus specimens reached body lengths of 16 to 33 feet (five to ten meters) and could weigh more than four tons. Because of its small size alone, it was obvious to assume that "Fabian" was a juvenile animal. This assumption was confirmed by the fact that the bone sutures of the spinal column had not yet closed. Background: Similar to skull sutures in human babies, bone sutures only fuse over the course of life.Researchers found that the young dinosaur resembled its older relatives both in anatomical details, such as the pattern of the laminae on the vertebrae (bony lamellae connecting parts of the vertebrae, which are important anatomical features in many dinosaurs), and in the rough proportions of its body. "The hands and neck of the juveniles may be a little longer, the arm bones a little shorter and slimmer. But overall, the variations are relatively small compared to the variation within the species overall and also compared to other dinosaur species," stresses Nau. The juveniles of the related Mussaurus for instance were still quadrupeds after hatching, but the adults were bipeds."The fact that the Plateosaurus juvenile already looked so similar to the adults is all the more remarkable considering that they were ten times heavier," emphasizes paleontologist Dr. Jens Lallensack from the University of Bonn. It is however conceivable that the morphological development differed greatly from animal to animal, depending on the climatic conditions or the availability of food. Such differences are still seen in reptiles today.The well-known descendants of Plateosaurus, the sauropods, are the subject of a current exhibition at the Zoological Research Museum Alexander Koenig in Bonn. The largest Plateosaurus skeleton ever found can be seen there.The study received financial support for the excavation and preparation of the skeleton from the municipality of Frick and the Canton of Argonia (Swisslos-Fonds) of Switzerland.
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Zoology
| 2,020 |
November 6, 2020
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https://www.sciencedaily.com/releases/2020/11/201106113856.htm
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phyloFlash: New software for fast and easy analysis of environmental microbes
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Researchers at the Max Planck Institute for Marine Microbiology in Bremen are developing a user-friendly method to reconstruct and analyze SSU rRNA from raw metagenome data.
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First the background: Microbiologists traditionally determine which organisms they are dealing with using the small subunit ribosomal RNA or in short SSU rRNA gene. This marker gene allows to identify almost any living creature, be it a bacterium or an animal, and thus assign it to its place in the tree of life. Once the position in the tree of life is known, specific DNA probes can be designed to make the organisms visible in an approach called FISH (fluorescence in situ hybridization). FISH has many applications, for example to sort cells, or to microscopically record their morphology or spatial position. This approach -- which leads from DNA to gene to tree and probe to image -- is called the "full-cycle rRNA approach." To make the SSU rRNA measurable, it is usually amplified with polymerase chain reaction (PCR). Today, however, PCR is increasingly being replaced by so-called metagenomics, which record the entirety of all genes in a habitat. Rapid methodological advances now allow the fast and efficient production of large amounts of such metagenomic data. The analysis is performed using significantly shorter DNA sequence segments -- much shorter than the SSU gene -- which are then laboriously assembled and placed into so-called metagenomically assembled genomes (MAGs). The short gene snippets do not provide complete SSU rRNA, and even in many assemblies and MAGs we do not find this important marker gene. This makes it hard to molecularly identify organisms in metagenomes, to compare them to existing databases or even to visualize them specifically with FISH.Researchers at the Max Planck Institute for Marine Microbiology in Bremen now present a method that closes this gap and makes it possible to reconstruct and analyze SSU rRNA from raw metagenome data. "This software called phyloFlash, which is freely available through GitHub, combines the full-cycle rRNA approach for identification and visualization of non-cultivated microorganisms with metagenomic analysis; both techniques are well established at the Max Planck Institute for Marine Microbiology in Bremen," explains Harald Gruber-Vodicka, who chiefly developed the method. "phyloFlash comprises all necessary steps, from the preparation of the necessary genome database (in this case SILVA), data extraction and taxonomic classification, through assembly, to the linking of SSU rRNA sequences and MAGs." In addition, the software is very user-friendly and both installation and application are largely automated.Gruber-Vodicka and his colleague Brandon Seah -- who are shared first authors of the publication now presenting phyloFlash in the journal phyloFlash is an OpenSource software. Extensive documentation and a very active community ensure its continuous testing and further development. "phyloFlash is certainly not only interesting for microbiologists," emphasizes Gruber-Vodicka. "Already now, numerous scientists from diverse fields of research make use of our software. The simple installation was certainly helpful in this respect, as it lowers the threshold for use." This easy access and interactive character is also particularly important to Brandon Seah, who now works at the Max Planck Institute for Developmental Biology: "The most satisfying thing for me about this project is to see other people using our software to drive their own research forward," says Seah. " From the beginning, we've added features and developed the software in response to user feedback. These users are not just colleagues down the hall, but also people from the other side of the world who have given it a try and gotten in touch with us online. It underlines how open-source is more productive and beneficial both for software development and for science."The software phyloFlash at GitHub: phyloFlash manual available at
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Zoology
| 2,020 |
November 5, 2020
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https://www.sciencedaily.com/releases/2020/11/201105115201.htm
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Nervous systems of insects inspire efficient future AI systems
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Zoologists at the University of Cologne studied the nervous systems of insects to investigate principles of biological brain computation and possible implications for machine learning and artificial intelligence. Specifically, they analysed how insects learn to associate sensory information in their environment with a food reward, and how they can recall this information later in order to solve complex tasks such as the search for food. The results suggest that the transformation of sensory information into memories in the brain can inspire future machine learning and artificial intelligence applications to solving complex tasks. The study has been published in the journal
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Living organisms show remarkable abilities in coping with problems posed by complex and dynamic environments. They are able to generalize their experiences in order to rapidly adapt their behaviour when the environment changes. The zoologists investigated how the nervous system of the fruit fly controls its behaviour when searching for food. Using a computer model, they simulated and analysed the computations in the fruit fly's nervous system in response to scents emanated from the food source. 'We initially trained our model of the fly brain in exactly the same way as insects are trained in experiments. We presented a specific scent in the simulation together with a reward and a second scent without a reward. The model rapidly learns a robust representation of the rewarded scent after just a few scent presentations and is then able to find the source of this scent in a spatially complex and temporally dynamic environment,' said computer scientist Dr Hannes Rapp, who created the model as part of his doctoral thesis at the UoC's Institute of Zoology.The model created is thus capable to generalize from its memory and to apply what it has learned previously in a completely new and complex odour molecule landscape, while learning required only a very small database of training samples. 'For our model, we exploit the special properties of biological information processing in nervous systems,' explained Professor Dr Martin Nawrot, senior author of the study. 'These are in particular a fast and parallel processing of sensory stimuli by means of brief nerve impulses as well as the formation of a distributed memory through the simultaneous modification of many synaptic contacts during the learning process.' The theoretical principles underlying this model can also be used for artificial intelligence and autonomous systems. They enable an artificial agent to learn much more efficiently and to apply what it has learned in a changing environment.
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Zoology
| 2,020 |
November 4, 2020
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https://www.sciencedaily.com/releases/2020/11/201104150014.htm
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Mimicking moth eyes to produce transparent anti-reflective coatings
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There is a huge number of human problems that scientists and engineers have solved by drawing ideas directly from mechanisms found in other lifeforms, from Velcro to Japan's famous bullet trains, the Shinkansen. Thus, it should not come as a surprise to know that many remarkable advances in anti-reflective coating were inspired by the peculiar biostructures found in moth eyes.
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As mainly nocturnal animals that wish to stay hidden from surrounding predators, moths have evolved to develop eyes that are non-reflective. Their eyes have a periodic nanometric structure that makes the eye surface graded, as opposed to polished. This causes most incident light to bend at the surface and therefore, be transmitted through the eye instead of being reflected off it. This nanoscale arrayed structure is so effective that researchers have tried to mimic it using other materials to create anti-reflective coatings with varying degrees of success.However, in spite of the recent progress in nanoscience that allows the adoption of this idea for various practical applications, there are still barriers to overcome in terms of scalability and cost of manufacturing. To tackle these problems, scientists from Tokyo University of Science and Geomatec Co., Ltd., Japan, have been working on a novel strategy to produce moth-eye nanostructures and transparent films. In their latest study, published in Though this research team had previously succeeded in creating moth-eye molds made of glassy carbon etched with an oxygen ion beam, this approach was not scalable. "Producing glassy carbon substrates requires the use of powder metallurgy technology, which is difficult to use to produce molds with a large area," explains Professor Jun Taniguchi from Tokyo University of Science, "To overcome this limitation, we tried using only a thin layer of glassy carbon deposited on top a large regular glass substrate."Moreover, to make this new strategy feasible, the team opted this time to use an inductively coupled plasma (ICP) system as opposed to the previously used electron-cyclotron resonance ion source. While both devices can etch glassy carbon using a concentrated beam of oxygen ions, ICP technology produces a wider ion beam irradiation range, which is more suitable for working on large-area structures.After testing with different ICP parameters, the researchers determined that a two-step ICP etching process was best to obtain a high-quality nanostructured mold. Then, they used this mold to produce a transparent film with a moth-eye nanostructure using a UV-curable resin.The optical properties of this film were remarkable; its reflectance toward light in the visible range was only 0.4%, ten times lower than that of a similar film without the moth-eye nanostructure. What's more, the transmittance of light through the material was also increased, meaning that no trade-off in optical properties occurred as a result of using the film to reduce reflected light.Mr Hiroyuki Sugawara, Chief Technical Officer at Geomatec, highlights the many possible applications of such anti-reflective films if it were possible to produce them at the meter scale: "We could use these films to improve visibility in flat panel displays, digital signs, and the transparent acrylic plates used everywhere since the start of the COVID-19 pandemic. Moreover, anti-reflective coating could also be an efficient way to improve the performance of solar panels."This study showcases how to expand the uses of biologically inspired structures by making their fabrication more easily scalable. Let us hope these technological advances help us preserve nature so that we can keep obtaining useful ideas from other species.
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Zoology
| 2,020 |
October 29, 2020
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https://www.sciencedaily.com/releases/2020/10/201029142019.htm
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Spring-run and fall-run Chinook salmon aren't as different as they seem
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Historically, spring-run and fall-run Chinook salmon have been considered as separate subspecies, races, ecotypes, or even as separate species of fish. A new genetic analysis, however, shows that the timing of migration in Chinook salmon is determined entirely by differences in one short stretch of DNA in their genomes.
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The new findings, published October 29 in "It's like blue and brown eye color in humans -- it just depends on what genotype you inherit from your parents," said corresponding author John Carlos Garza, adjunct professor of ocean sciences at UC Santa Cruz and a research geneticist with NOAA's Southwest Fisheries Science Center.The study has profound implications for conservation and management of Chinook salmon, the largest species of salmon, and makes restoration of the beleaguered Klamath River spring run more feasible if plans for the removal of dams on the river move forward."We view this as very good news," Garza said.Garza's team began by sequencing the complete genomes of 160 Chinook salmon from the Klamath River and Sacramento River drainages. The only consistent differences they found between spring-run and fall-run fish occurred within a single region on chromosome 28. Within that region, they identified a shorter "Region of Strongest Association" (RoSA) that occurs in two versions, "E" for early migration and "L" for late migration.RoSA includes parts of two genes and the stretch of DNA between them. The E and L versions differ in multiple places, making them "haplotypes," the term for a set of DNA variations that are inherited together. Salmon, like all vertebrates, inherit two sets of chromosomes, one from each parent, so their RoSA "genotype" can be either EE, LL, or EL.Armed with genetic markers for the E and L haplotypes, the researchers sampled 502 Chinook salmon harvested by the Yurok Tribe in the Klamath River Estuary. For fish with the "homozygous" EE and LL genotypes, there was no overlap in the timing of migration, when the fish leave the ocean to swim up the Klamath and spawn. EE fish migrate early (spring run), and LL fish migrate later (fall run).Fish with the "heterozygous" EL genotype had intermediate migration times, overlapping with those of the homozygous genotypes. The migration times of EL salmon were skewed toward the spring run, but some overlapped with fall-run salmon.According to Garza, these results show that seasonal differences in migration are completely attributable to the RoSA genetic variants. "That was an extraordinary finding," he said. "I know of no other gene region that so completely determines a complex migratory behavior in the wild in a vertebrate."This finding is especially striking because people have long noted differences between spring-run and fall-run salmon in their fat content and other features, which were presumed to be part of a suite of heritable traits characterizing the different runs. But in fact, Garza said, all those differences are tied to the timing of migration as determined by the RoSA genotype.Spring-run salmon enter freshwater early in the year, where they encounter different environmental conditions, notably warmer water, which likely accelerates their maturation. The fish spend the summer in cool, deep pools near their spawning habitat before spawning in the fall."Spring-run and fall-run fish all start maturing at the same time in the ocean, but during that period after the spring run enters freshwater, they experience different environmental conditions, leading to differences in where and when they spawn," Garza said. "Also, people notice differences in fat content and body condition because they are encountering spring-run fish earlier in the maturation process than fall-run fish."When the researchers sampled the carcasses of salmon that had died after spawning in the Salmon River, a major tributary of the Klamath, they found evidence that the spring-run and fall-run salmon were freely interbreeding. The ratios of EE, LL, and EL genotypes were close to what would be expected for random mating patterns. Garza noted that if two EL fish mate, their offspring will include EE, LL, and EL fish.In other words, a spring-run salmon can have a fall-run sibling."It's hard to come up with any scenario where you could classify individuals from the same nest as belonging to different populations," he said. "For me, one of the underlying messages is that, in our attempt to categorize things, we've overlooked the fact that these are fundamentally the same animal."The researchers extended their survey of post-spawning carcasses to rivers throughout northern California and the Siletz River in Oregon. Again, they found that heterozygous (EL) fish were widespread where early-migrating fish occur and suitable habitat for them exists.The researchers also found that the RoSA haplotypes are the same in all the Chinook salmon lineages found in different rivers, indicating that they predate the evolution of genetically distinct lineages adapted to specific drainages along the coast."Those haplotypes are ancestrally the same everywhere, which is good news because it means that there are no variants related to the spring-run migration trait that have been lost with the extirpation of the historically abundant spring run in the upper Klamath River," Garza said.Dams have blocked migrating salmon from the upper reaches of the Klamath River since 1912. Salmon lineages that used to spawn in the upper Klamath now stop at the Iron Gate Dam and spawn below there. The dams also reduced the cool-water habitat needed by spring-run salmon to survive during the summer, selecting against the EE and EL genotypes. But Garza's team found that Chinook salmon with the genetic traits for local adaptation to the upper Klamath still persist below the dam."It highlights the importance of taking those dams out, because descendants of the historic upper Klamath spring run are still there -- they've just lost the E haplotype," Garza said. "Simple crossing with other populations in the Klamath to put the E haplotype back into the genetic background of upper Klamath Chinook salmon could restore that spring run."
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Zoology
| 2,020 |
October 29, 2020
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https://www.sciencedaily.com/releases/2020/10/201029105115.htm
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Boo! How do Mexican cavefish escape predators?
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The ability to detect threatening stimuli and initiate an escape response is critical for survival and under stringent evolutionary pressure. To detect predators, fish use a number of sensory systems including olfaction (smell) and vision, which contribute to the activation of arousal systems. Surprisingly, little is known about the neural mechanisms through which ecological perturbation shapes the evolution of escape response. When startled, do all fish respond the same way?
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A few fish, like Mexican cavefish, Astyanax mexicanus, have evolved in unique environments without any predators. To determine how this lack of predation impacts escape responses that are highly stereotyped across fish species, researchers from Florida Atlantic University's Charles E. Schmidt College of Science and Harriet L. Wilkes Honors College explored the tiny A. mexicanus to determine if there are evolved difference in the species. A. mexicanus exist as surface fish that inhabit rivers in Mexico and Southern Texas and as more than 30 geographically isolated cave-dwelling populations of the same species.The ecology of caves differs dramatically from the surface habitat, resulting in distinct morphological and behavioral phenotypes in A. mexicanus. Cave populations live in environments without light, which is thought to contribute to the evolution of albinism, eye-loss, and circadian rhythm. Because they lack predators they might also lack the selective pressure to avoid predators. Dramatic differences in these cavefish populations combined with the robust ecological differences suggest that the startle reflex could indeed differ between populations of A. mexicanus.To put this theory to the test, researchers elicited "C-start" responses using acoustic stimuli and high-speed videography in multiple cavefish populations and compared responses to eyed surface fish. The C-start escape response represents a primary mechanism for predator avoidance in fish and amphibians. C-start gets its name from the "c-shaped" curve a fish's body forms during the first stage of the escape response, which is followed by a smaller counter-bend and then rapid swimming.Results of the study, published in a special issue of the In diverse fish species, acoustic stimuli activate Mauthner neurons, which initiate a C-start escape response. Mauthner cells receive input from multiple sensory modalities including visual, olfactory, and mechanosensory systems. To compare C-start kinematics between surface fish and cavefish, researchers examined and quantified response latency, maximum change in orientation (referred to as "peak bend angle") and angular speed. They used six-day post-fertilization larvae instead of adult surface fish and cavefish to eliminate the confounding variable of learned behavior.Researchers found that C-start is present in river-dwelling surface fish and multiple populations of cavefish, but response kinematics and probability differed between populations. The Pachon population of cavefish exhibited an increased response probability, a slower response latency and speed, and reduction of the maximum bend angle, revealing evolved differences between surface and cave populations. Analysis of the responses of two other independently evolved populations of cavefish, revealed the repeated evolution of reduced angular speed. Investigation of surface-cave hybrids showed a correlation between angular speed and peak angle, suggesting that these two kinematic characteristics are related at the genetic or functional levels."These findings show that even the most highly conserved behaviors have evolved differences in the cave environment," said Alex Keene, Ph.D., lead author and an associate professor of biological sciences, FAU's Charles E. Schmidt College of Science. "It puts us in a position to identify the biological causes that underlie the reduced response probability and other changes we observed between cavefish and surface fish."Keene notes that perhaps most interesting, is the difference in response probability in which Molino cavefish which diverged from surface fish more recently, were significantly more responsive than any of the other populations, with Pachon larvae, originating from the more ancestral stock, exhibiting the second highest response probability."The finding that multiple populations independently evolved similar phenotypes gives us a way to examine how escape circuits can be modified," said Keene.Despite having no eyes, cavefish could detect light and sense looming stimuli, raising the possibility that light modulates their C-start response. To assess the influence of visual input on the C-start responses of surface fish and cavefish, researchers assayed both populations under light and dark conditions. The presence of light had no detectable effect on response probability, response latency, or angular speed in cavefish or surface fish. It did however, influence peak bend angle. In the dark conditions, surface fish displayed an increase in peak bend angle compared to cavefish. Although they were able to perceive light at this age, the presence or absence of light had no observable effect on the responses of Pachon cavefish.To assess differences in responsiveness to acoustic stimuli, researchers quantified the probability of C-start initiation in surface fish and Pachon cavefish at multiple vibration intensities. They found that Pachon cavefish were more likely than surface fish to initiate a C-start in response to vibrations of higher intensities (31 and 35 decibels, but not 28 decibels)."Interestingly, all cave populations analyzed in our study exhibited decreased angular speed. Furthermore, it is likely that a slower latency, such as that of Pachon larvae, decreases the likelihood of successful evasion," said Alexandra Paz, first author, an FAU doctoral student and a research assistant in the Department of Biological Sciences. "These data suggest that the C-start responses of cavefish, especially from the Pachon population, may be less effective for successful predator evasion. Because no predators have been identified in the caves, it is possible that this change is a result of diminished predation in the cave environment."
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Zoology
| 2,020 |
October 28, 2020
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https://www.sciencedaily.com/releases/2020/10/201028143120.htm
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Multi-drone system autonomously surveys penguin colonies
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Stanford University researcher Mac Schwager entered the world of penguin counting through a chance meeting at his sister-in-law's wedding in June 2016. There, he learned that Annie Schmidt, a biologist at Point Blue Conservation Science, was seeking a better way to image a large penguin colony in Antarctica. Schwager, who is an assistant professor of aeronautics and astronautics, saw an opportunity to collaborate, given his work on controlling swarms of autonomous flying robots.
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That's how, three-and-a-half years later, Schwager's graduate student, Kunal Shah, found himself at the famous McMurdo Station, ready for the first Antarctic test flight of their new multi-drone imaging system, which coordinates the flight of multiple high-end autonomous drones -- but can also work with hobby drones.The project did not have an auspicious start. "My hands were freezing. The drone batteries were too cold to work. The drone remote control was too cold. My phone was too cold and was flashing warnings," recalled Shah. "I just thought, 'I'm down here for two-and-a-half months and this is day one?"Undeterred, Shah and his colleagues quickly adapted and their system, which is the subject of a paper published Oct. 28 in "Just moving all of that equipment down to a remote site and being able to prepare it, field it and deploy it with nothing other than tents and a small warming hut at your disposal, that's really phenomenal," said Schwager, who is senior author of the paper but, to his disappointment, was not able to join the field team. "It really goes to show how practical autonomous robotic systems can be in remote environments."Aerial surveys of penguin colonies have been conducted before, usually with helicopters or a single drone. The helicopter method produces great image quality but is expensive, fuel-inefficient and risks disturbing the birds. The single drone survey is time-consuming and -- because the drones must be launched from a safe distance, about five kilometers (three miles) from the colony -- difficult to navigate. Another shortcoming of drones is that they must fly to, over and back from the colony with only 12-15 minutes of battery life. The continuous threat of sudden changes in flying conditions further adds to the importance of a fast survey.The use of multiple drones circumvents these challenges, and it was made possible by a unique route planning algorithm developed by the Stanford researchers. Given a survey space, the algorithm partitioned the space, assigned destination points to each drone and figured out how to move the drones through those points in the most efficient way, limiting backtracking and redundant travel. One crucial additional requirement was that each drone exit the space at the same place where it entered, which saves precious flight time. The algorithm also maintained a safe, constant, distance from the ground despite the changes in elevation, and had a tunable image overlap percentage to assure a complete survey. Unlike the back-and-forth action of a robotic vacuum, Schwager described the algorithm's paths as "organic and spidery.""The process was quick. What had been just the algorithm's squiggles on a screen the day before turned into a massive image of all the penguins in the colonies," said Shah, who is lead author of the paper. "We could see people walking around the colonies and all the individual birds that were nesting and coming to and from the ocean. It was incredible."The researchers envision other uses for their multi-drone system, such as traffic monitoring and tracking wildfires. They've already performed tests in some varied settings. They have flown over a large ranch in Marin, California, to assess the vegetation available for livestock grazing. They also took their drones out to Mono Lake near the California-Nevada border to survey the California gull population that lives near Paoha Island in the lake's center. Like Antarctica, the Mono Lake test had its own challenges -- the birds were smaller, the researchers had to boat out to the site before releasing the drones and there was a risk of losing drones in the water (which, fortunately, did not happen).For their part, the penguin biologists remain focused on measuring population size, birth rates and nesting density and will conduct a second round of penguin observation this year. Due to the pandemic, however, the Point Blue Conservation Science team will be on their own this time.Thinking about the big picture -- in the figurative sense -- the researchers hope their system stands as evidence for the positive potential of autonomous robots and systems."Humans could never leap into the sky and count 300,000 penguins or track a forest fire," said Schwager. "I think that teams of autonomous robots can really be powerful in helping us manage our changing world, our changing environment, at a scale that we never could before."The researchers from Point Blue Conservation Science are also co-authors of the paper. This work was funded by the National Science Foundation.
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Zoology
| 2,020 |
October 28, 2020
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https://www.sciencedaily.com/releases/2020/10/201028082952.htm
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Mountain gorillas are good neighbors - up to a point
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Mountain gorilla groups are friendly to familiar neighbours -- provided they stay out of "core" parts of their territory -- new research shows.
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Gorillas live in tight-knit groups, foraging, resting and sleeping together around a "core home range" and a wider "peripheral" range.These groups sometimes split permanently, separating gorillas that may have lived together for years and may be closely related.The new study -- by the Dian Fossey Gorilla Fund (Fossey Fund) and the University of Exeter -- shows groups that were previously united are more than four times as likely to be friendly to each other when they meet, even if they had split over a decade earlier.Gorillas tend to react aggressively when another group strays into their core territory -- regardless of whether the intruders are familiar. But in the peripheries of their home range, this heightened aggression only applies to less familiar groups, with groups that were previously united more tolerant of each other."Meetings of groups are fairly rare, and at first both groups are usually cautious," said Dr Robin Morrison, of the Fossey Fund and Exeter's Centre for Research in Animal Behaviour."They often beat their chests and show off their strength, but the interaction can then either become aggressive -- with fighting and screaming -- or 'affiliative'."In affiliative interactions, the initial tension passes and the groups intermingle. They may rest together, and younger gorillas will often play with youngsters from the other group."Humans have an unrivalled capacity for cooperation based on the friendships that extend beyond our immediate group, and one theory for the evolutionary benefit of these wider friendships is that they allow shared access to space and resources with a reduced risk of aggression.The new study is the first to test this theory beyond humans -- and the findings suggest gorillas may indeed benefit in this way from maintaining "friendships" between groups."The pattern we found mirrors what we see in humans," Dr Morrison said."We also have concepts of public spaces outside our 'range' where we tolerate anyone, spaces like our homes where we tolerate certain individuals, and private spaces within those homes reserved for close family or just ourselves."Understanding these patterns is also important for conservation."Mountain gorillas have less than 800 km2 of habitat remaining," said Jean Paul Hirwa, Gorilla Program Manager at the Fossey Fund and co-author on the study."As a result of extreme conservation efforts, the population has been growing over the last 30 years while their habitat has not.""Understanding how groups interact and share their limited space is important for estimating future population dynamics and trends in this endangered species."
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Zoology
| 2,020 |
October 27, 2020
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https://www.sciencedaily.com/releases/2020/10/201027092211.htm
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Gut bacteria associated with animal-based diet may mitigate risk of cardiovascular disease
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Oregon State University researchers have found that a type of common gut bacteria sometimes associated with inflammation, abscesses, bowel disease and cancer has a major silver lining: It seems to help prevent cardiovascular disease.
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The findings suggest the possibility of probiotic treatments for atherosclerosis, the dangerous buildup of fats, cholesterol and other substances in arteries that cause strokes and heart attacks and is linked to smoking, diet, age and a range of genetic causes.Diets heavy in animal-based foods have long been considered a risk factor for cardiovascular disease as such diets are a major source of TMA -- trimethylamine -- which is converted by the liver to another compound, TMAO, that promotes the buildup of fatty plaque in arteries. TMAO is short for trimethylamine-N-oxide."The connection between TMAO and cardiovascular disease has tended to focus the conversation on how animal-based diets cause negative health consequences," said Veronika Kivenson, the study's lead author and a postdoctoral fellow in the OSU College of Science. "But in analyzing data from foundational gut microbiome studies, we uncovered evidence that one type of bacteria associated with meat consumption can take the TMA, as well as precursors to TMA, and metabolize them without producing any TMAO. That means those bacteria are in effect severing a key link in the cardiovascular disease chain."The bacteria are of the Bilophila genus and evidence suggests an expanded genetic code enables their metabolism, via a demethylation pathway, to avoid making TMAO. Furthermore, Kivenson said, research shows animal-based diets cause a rapid increase in Bilophila in the gut."The organisms in your stomach have been shown to affect the development of myriad disease states," said co-author Steve Giovannoni, distinguished professor of microbiology at OSU. "But the mechanisms -- what is actually happening behind the connections among diet, health and microbiota -- have generally been hard to pin down. More research into Bilophila cell biology and ecology is needed, but our study presents a clearly defined mechanism with potential for a big impact on human health."Identified only 31 years ago, in an infected appendix, Bilophila is a gram-negative anaerobic rod that's classified as a pathobiont -- an organism that normally has a symbiotic relationship with its host but can become disease-causing under certain circumstances. It's commonly present in the microbiomes of people who are healthy."The data we reviewed show significantly more Bilophila in the microbiomes of healthy people compared to those with cardiovascular disease, and that Bilophila numbers go up in response to a diet based on meat compared to a plant-based diet," Kivenson said. "Our findings suggest Bilophila's role in the microbiome and human health might depend on the specific context and that their potential as a probiotic that mitigates animal products' role in heart disease should be studied further."Findings were published today in
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Zoology
| 2,020 |
October 26, 2020
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https://www.sciencedaily.com/releases/2020/10/201026081453.htm
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Robots help to answer age-old question of why fish school
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A fish school is a striking demonstration of synchronicity. Yet centuries of study have left a basic question unanswered: do fish save energy by swimming in schools? Now, scientists from the Max Planck Institute of Animal Behavior (MPI-AB), the University of Konstanz, and Peking University have provided an answer that has long been suspected but never conclusively supported by experiments: yes.
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Using biomimetic fish-like robots, the researchers show that fish could take advantage of the swirls of water generated by those in front by applying a simple behavioural rule. By adjusting their tail beat relative to near neighbours -- a strategy called vortex phase matching -- robots were shown to benefit hydrodynamically from a near neighbour no matter where they are positioned with respect to that neighbour. The previously unknown rule, revealed by the robots, was subsequently shown to be the strategy used by free swimming fish. The study is reported on 26 October 2020 in"Fish schools are highly dynamic, social systems," says senior author Iain Couzin, Director of the MPI-AB who also co-directs the Cluster of Excellence 'Centre for the Advanced Study of Collective Behaviour' at the University of Konstanz. "Our results provide an explanation for how fish can profit from the vortices generated by near neighbours without having to keep fixed distances from each other."Answering the question of whether or not fish can save energy by swimming with others requires measuring their energy expenditure. Accurately doing so in free swimming fish has so far not been possible, and so past studies have sought to answer this question instead through theoretical models and predictions.The new study, however, has overcome this barrier to experimental testing. The researchers developed a 3D robotic fish that has a soft tail fin and swims with an undulating motion that mimics accurately the movement of a real fish. But unlike their live counterparts, the robots allow for direct measurement of the power consumption associated with swimming together versus alone."We developed a biomimetic robot to solve the fundamental problem of finding out how much energy is used in swimming," says Liang Li, a postdoctoral fellow at the MPI-AB and first author on the study. "If we then have multiple robots interacting, we gain an efficient way to ask how different strategies of swimming together impact the costs of locomotion."The researchers studied robotic fish swimming in pairs versus alone. Running over 10,000 trials, they tested follower fish in every possible position relative to leaders -- and then compared energy use with solo swimming.The results showed a clear difference in energy consumption for robots that swam alone versus those that swam in pairs. The cause of this, they discovered, is the way that fish in front influence the hydrodynamics of fish behind. The energy consumed by a follower fish is determined by two factors: its distance behind the leader and the relative timing of the tail beats of the follower with respect to that of the leader. In other words, it matters whether the follower fish is positioned close to the front or far behind the leader and how the follower adjusts its tail beats to exploit the vortices created by the leader.To save energy, it turns out that the secret is in synchronisation. That is, follower fish must match their tail beat to that of the leader with a specific time lag based on the spatial position -- a strategy the researchers called "vortex phase matching." When followers are beside leader fish, the most energetically effective thing to do is to synchronise tail beats with the leader. But as followers fall behind, they should go out of synch having more and more lag as compared to the tail beat of the leader.In order to visualise the hydrodynamics, researchers emitted tiny hydrogen bubbles into the water and imaged them with a laser -- a technique that made the vortices created by the swimming motion of the robots visible. This showed that vortices are shed by the leader fish and move downstream. It also showed that robots could utilise these vortices in various ways. "It's not just about saving energy. By changing the way they synchronise, followers can also use the vortices shed by other fish to generate thrust and help them accelerate," says co-author Mate Nagy, head of the Collective Behaviour 'Lendület' Research Group in the Hungarian Academy of Sciences and Eötvös University, who conducted the work when he was a postdoctoral fellow at the MPI-AB.But do real fish use the strategy of vortex phase matching to save energy? To answer that, the researchers created a simple hydrodynamic model that predicts what real fish should do if they are using vortex phase matching. They used AI-assisted analysis of body posture of goldfish swimming together and found, indeed, that the strategy is being used in nature.Says Couzin: "We discovered a simple rule for synchronising with neighbours that allows followers to continuously exploit socially-generated vortices. But before our robotic experiments, we simply didn't know what to look for, and so this rule has been hidden in plain sight."Video:
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Zoology
| 2,020 |
October 23, 2020
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https://www.sciencedaily.com/releases/2020/10/201023191027.htm
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Fipronil, a common insecticide, disrupts aquatic communities in the U.S.
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The presence of insecticides in streams is increasingly a global concern, yet information on safe concentrations for aquatic ecosystems is sometimes sparse. In a new study led by Colorado State University's Janet Miller and researchers at the United States Geological Survey, the team found a common insecticide, fipronil, and related compounds were more toxic to stream communities than previous research has found.
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The study, "Common insecticide disrupts aquatic communities: A mesocosm to field ecological risk assessment of fipronil and its degradates in U.S. streams," is published Oct. 23 in Fipronil is used in the U.S. for insect control on pets, structures, yards and crops. Most of the streams where fipronil compounds were found to exceed toxic levels were in the relatively urbanized Southeast region.Miller said the insecticide is likely affecting stream insects and impairing aquatic ecosystems across the country at lower levels than previously thought. In addition, fipronil degrades into new compounds, some of which this study found to be more toxic than fipronil itself.The research team also found delayed or altered timing of when these insects emerged from streams, which has implications for the connections between stream and land-based communities."The emerging insects serve as an important food source," Miller explained. "When we see changes, including a drop in emergence rates or delayed emergence, it's worrisome. The effects can reverberate beyond the banks of the stream."In experimental settings that had a high concentration of fipronil, the researchers also saw a reduced number of insects that scrape or eat algae off the rocks, leading to an increase of algae in those streams.In this study, the research team studied the effects of fipronil compounds on aquatic macroinvertebrates, insects that live on the rocks and sediment of stream bottoms. Examples of these insects include mayflies, stoneflies and caddisflies. These creatures spend the larval life stage in streams as aquatic invertebrates, later emerging from streams as flying insects."These macroinvertebrates serve as an important food source for fish and other organisms while also playing an important role in nutrient cycling ," said Miller, an aquatic ecologist with the Colorado Natural Heritage Program, which is part of the Warner College of Natural Resources at Colorado State University.As one part of the study, the research team built rock trays to mimic the invertebrate's habitat, and placed them in the Cache La Poudre River in northern Colorado. In these habitats, the macroinvertebrates colonized naturally with algae to mimic communities that exist in nature.Next, the scientists moved the rock trays containing macroinvertebrates into the lab, mimicking a natural environment while also controlling temperature, light and water flow. The team then added a range of concentrations of the insecticide fipronil or one of four associated fipronil degradate compounds -- sulfone, sulfide, desulfinyl and amide -- and observed the effects on macroinvertebrates.Scientists found these degradates to be as toxic, if not more so than fipronil. Yet Miller said there is generally a lack of data for the compounds.As an additional prong of the research, Miller and the team applied results from the laboratory experiment to data from a large field study conducted by the United States Geological Survey that sampled streams across the U.S. in five major regions.Miller said fipronil compounds were detected at unsafe concentrations in 16% of streams sampled across the U.S. and were most prevalent in streams of the Southeast region of the country. Scientists found fipronil compounds much less widespread in other regions, suggesting use patterns of the insecticide differ across the country."We found that 51% of sampled streams in the southeast revealed the presence of fipronil, while in the Pacific Northwest, we detected only around 9% of streams with the insecticide," she said.Miller said that while the results are concerning, it's helpful to have this scientific-based evidence to share with the scientific community and regulating agencies."We hope our findings provide greater understanding of the prevalence of fipronil compounds across the country and the levels at which these compounds are harmful to stream health," she said.
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Zoology
| 2,020 |
October 23, 2020
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https://www.sciencedaily.com/releases/2020/10/201023123100.htm
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Fish exposed to even small amounts of estrogen produce fewer males
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Water tainted with even a small concentration of human hormones can have profound effects on fish, according to a University of Cincinnati biologist.
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UC assistant professor Latonya Jackson conducted experiments with North American freshwater fish called least killifish. She found that fish exposed to estrogen in concentrations of 5 nanograms per liter in controlled lab conditions had fewer males and produced fewer offspring.Scientists have found estrogen at as much as 16 times that concentration in streams adjacent to sewage treatment plants.The study suggests that even this small dose of estrogen could have significant consequences for wild fish populations living downstream from sewage treatment plants.The study was published this week in the journal What's special about least killifish is they have a placenta and give birth to live young, Jackson said. It's uncommon among fish, who more typically lay eggs.Jackson studied a synthetic estrogen called 17α-ethinylestradiol, an active ingredient in oral contraceptives also used in hormone replacement therapy. Estrogen been found in streams adjacent to sewage treatment plants in concentrations of as high as 60 nanograms or more per liter."Anything you flush down the toilet or put in the sink will get in the water supply," she said.This includes not only medicine people flush (never do that) but also unmetabolized chemicals that get flushed when people use the bathroom."Our wastewater treatment systems are good at removing a lot of things, but they weren't designed to remove pharmaceuticals," Jackson said. "So when women on birth control or hormone therapy go to the bathroom, it gets flushed into wastewater treatment plants."Chronic exposure of fish to estrogen led to smaller populations and a gender ratio imbalance with more females than males.Now Jackson wants to know how the exposure to hormones such as estrogen and androgen in a female fish affects her offspring. She is collaborating with the U.S. Environmental Protection Agency to examine local waters in southwestern Ohio.Jackson said the impacts on streams are not limited to fish. Hormones and other chemicals that are not removed during treatment can bioaccumulate in the food chain or end up in our drinking water."Our drinking water is not a renewable resource. When we run out of clean drinking water, it's gone," Jackson said. "It's very important that we keep this resource clean."
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Zoology
| 2,020 |
October 21, 2020
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https://www.sciencedaily.com/releases/2020/10/201021111611.htm
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Animal-based research: New experimental design for an improved reproducibility
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In research, the results of studies must be precise and reproducible. For this reason, researchers carried out experiments under strictly standardized laboratory conditions. However, despite the high standards applied, results from individual studies cannot always be reproduced in practice. Especially in cases in which animals are used for research purposes and the original study cannot be repeated, this raises severe ethical questions. For a long time now, researchers have been debating this aspect under the heading "reproducibility crisis." Behavioural scientists at the University of Münster have now been able to demonstrate that a new experimental design can improve the reproducibility and validity of results from studies involving animal experiments. The study has been published in the journal
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What animal scientists usually understand by "standardized experimental conditions" is that for example all the animals are tested on the same day in spring, at the same time and by the same person. Just taking a different season or time, however, can lead to different findings. Nowadays, there are debates more and more often as to whether the very strict standardization might not actually be the cause of numerous non-reproducible results. This is where the empirical study carried out by the Münster researchers comes in.Instead of testing all the animals used in an experiment under strictly standardized conditions and at one point in time, the researchers split up the one big experiment into smaller, individual ones -- so-called 'mini-experiments'. As a result, there were slight differences between 'mini-experiments' in laboratory-specific ambient conditions such as noise level or temperature. "It's important that the biological variation found in real life is reflected in the lab," explains Vanessa von Kortzfleisch, a PhD student with Prof. Helene Richter at the Institute of Neuro- and Behavioural Biology at Münster University and first author of the study. "We were able to demonstrate," she adds, "that changing the design of the experiment slightly has enormous consequences for the knowledge gained."The new experimental design was tried out on mice from different breeding lines, with several weeks between each 'mini-experiment'. In order to evaluate the reproducibility of the results in both experimental designs, the researchers repeated the same behavioural experiment four times in each design. "The results from the mini-experiment design turned out to be better reproducible than the results from the conventionally used standardized design," says Vanessa von Kortzfleisch.Improving study designs is one important step towards better reproducible experiments in animal-based research. Although many animal experiments are still indispensable, there is agreement on limiting them to the minimum necessary, with guidance being provided by the "3R concept": replacement, reduction and refinement. The newly developed experimental design is not only easy to implement in research work, it also makes a significant contribution to the refinement and reduction of such experiments.
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Zoology
| 2,020 |
October 19, 2020
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https://www.sciencedaily.com/releases/2020/10/201019155918.htm
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Immune protein orchestrates daily rhythm of squid-bacteria symbiotic relationship
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Nearly every organism hosts a collection of symbiotic microbes -- a microbiome. It is now recognized that microbiomes are major drivers of health in all animals, including humans, and that these symbiotic systems often exhibit strong daily rhythms.
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New research led by University of Hawai'i at Manoa scientists revealed that, in the mutually beneficial relationship between with the Hawaiian bobtail squid, Euprymna scolopes, and the luminescent bacterium, Vibrio fischeri, an immune protein called "macrophage migration inhibitory factor" or "MIF," is the maestro of daily rhythms. This finding, published in the To survive, the nocturnal Hawaiian bobtail squid depends on V. fischeri, which gives it the ability to mimic moonlight on the surface of the ocean and deceive monk seals and other predators, as it forages for food. The symbiotic bacteria also require nutrition, especially at night when they are more numerous and their light is required for the squid's camouflage.The research team, led by Eric Koch, who was a graduate researcher at the Pacific Biosciences Research Center (PBRC) in the UH Manoa School of Ocean and Earth Science and Technology (SOEST) at the time of the study, determined the squid regulates production of MIF as a way to control the movement of specialized immune cells, called hemocytes, which provide chitin for bacteria to feed on.At night, when the team found MIF was low in the squid's light organ, hemocytes were allowed into the regions where the bacteria reside and chitin was delivered. During the day, MIF was very high, which inhibits the hemocytes from coming into the symbiotic tissues and dumping their chitin at the wrong time.This cycling of nutrients has cascading effects on all of the other rhythms associated with the symbiotic system -- perhaps affecting overall health, development or reproduction.For nearly three decades, professors Margaret McFall-Ngai and Edward Ruby at PBRC have used the squid-bacterial symbiosis system to characterize animal microbiomes."We had recognized daily rhythms in the squid-vibrio symbiosis since 1996, but how the rhythm is controlled was not known," said McFall-Ngai. "This study brought the whole thing into sharp focus, allowing us to understand how the rhythm works and how it matures in the animal."Such discoveries can pave the way for understanding how microbiomes function -- what they do and how they do it -- in other organisms and environments."A recent study of the mammalian, and human, gut microbiome has shown that MIF is present at high levels and controls the interactions of the microbes with the host cell," said McFall-Ngai. "As has happened with other phenomena, such a developmental inducers, the simplicity of the squid-vibrio system has provided a window into the mechanisms of symbiosis. Because these mechanisms appear to be highly conserved among all animals, including humans, understanding how they function promises to give us the tools to foster healthy people and resilient ecosystems."
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Zoology
| 2,020 |
October 15, 2020
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https://www.sciencedaily.com/releases/2020/10/201015003441.htm
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Australian carp virus plan 'dead in the water'
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Plans to release a virus to reduce numbers of invasive Common Carp in Australia are unlikely to work and should be dropped, researchers say.
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Australian Government scientists have asked for approval to release Koi Herpesvirus (KHV) into the continent's largest freshwater supply to kill non-native carp.The new study, by the University of Exeter and the University of East Anglia, demonstrates that Common Carp would evolve resistance to the virus and carp numbers would soon recover.Carp can cause ecological damage in large numbers by uprooting vegetation and increasing sediment in the water, with significant knock-on effects for other species in the ecosystem.This means control is required -- but the study says releasing KHV is not the answer."Viral biocontrol is highly questionable and, as our study shows, it is unlikely to reduce carp numbers in the long term," said Dr Jackie Lighten, of the University of Exeter."Our modelling shows that even under the most optimal conditions for biocontrol, populations quickly recover."Releasing KHV carries significant risks to human and ecosystem health, which likely outweigh the benefits, and we have previously urged further detailed research to avoid an unnecessary ecological catastrophe."Based on our findings, we believe the plan to control Australia's carp with KHV is dead in the water."Dr Lighten previously argued in the Australian Senate that the country's National Carp Control Program (NCCP) was omitting key areas of research from its work.A key component of this is computer simulation modelling to assess if the virus would effectively kill the fish in light of the genetic component of resistance to KHV, which resides in the global carp population.Dr Katie Mintram, of the University of Exeter, said: "Modelling the epidemiology of proposed viral releases is essential for risk assessment and estimation of likely outcomes."We built a simulation model which allowed us to examine realistic interactions among carp, virus and disease resistance, to estimate how long it would take carp populations to recover even if 95% of them were wiped out."We show that the biological characteristics of the carp, including their rapid breeding rates, allow infected populations to recover rapidly with individuals that are KHV resistant."The authors modelled a "best-case scenario" for the virus to eradicate carp -- but the carp population still evolved resistance, making future outbreaks of the virus ineffective."The modelling strategy that we took is a very powerful way to assess how disease can spread among individuals within a population," said Professor Cock van Oosterhout, of the University of East Anglia."It's an 'Individual Based Model', which is similar to those used by scientists around the world to understand and prevent the spread of Covid-19."It is widely accepted as the current gold standard in projecting disease outcomes but, worryingly, the NCCP chose to ignore this approach."Also, they didn't model the impact of disease resistance, which is crucial in understanding the epidemiology of infectious disease."KHV appeared in European aquaculture (fish farming) facilities in the late 1990s and rapidly spread around the world, resulting in the deaths of millions of carp.Common Carp are among the world's most farmed fish for food, popular pets (Koi) and a prized fish for recreational angling. KHV has caused millions of dollars of damage worldwide.Dr Lighten said: "We recommend that the Australian Government takes bold steps to significantly improve the health of its waterways, rather than releasing a potentially catastrophic virus into its ecosystems."Freshwater is in desperate shortage in large parts of Australia, so the first step must be to reduce the amount of water extracted for thirsty crops such as cotton."This would help to restore habitat for native species, thereby reducing habitat for carp."Proper governance is what's needed, rather than giving an unhealthy and fragile ecosystem a foreign virus, which could significantly tip the balance out of favour for native species."Dr Lighten added: "If the current global Covid-19 pandemic has reminded of anything, it's that viruses are hard to predict and manage."It is madness that the release of a high pathogenic virus is being considered as one of the first steps to restore a damaged and fragile ecosystem."This is even more so, considering that very little progress has been made in reducing the volume of water extracted from the Murray-Darling Basin, which should be primary in restoring river health over releasing a pathogen that could have significant ecological repercussions."
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Zoology
| 2,020 |
October 14, 2020
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https://www.sciencedaily.com/releases/2020/10/201014140956.htm
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An alternative to animal experiments
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The human intestine is vital for both digestion and absorbing nutrients as well as drugs. For any type of research that involves intestines, scientists require research models that reflect the physiological situation inside human beings with the highest possible accuracy.
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Standard cell lines and animal experiments have certain disadvantages. One main issue is the lack of applicability of the results to humans. Now, a multidisciplinary research team covering the areas of nutritional science, general medicine, and chemistry has demonstrated how a modern in vitro model -- made from human intestinal biopsies -- can answer various questions regarding the molecular processes inside the human gut.A few years ago, researchers Eva Rath and Tamara Zietek have already demonstrated some areas of application of intestinal organoids. These are microstructures similar to the gut, which possess utility for the scientific field examining the gastro-intestinal system.For instance, these miniature intestines can serve as models for investigating hormone release and transport mechanisms of food or medication inside the digestive tract. Previously, these microstructures with their similarity to intestines were grown from mouse tissue. Now the team has found a way to apply this method to miniature intestines grown from human tissue, thereby expanding the methodological spectrum.Organoids consist of so-called epithelial cells -- a cell layer serving as barrier between the content of the bowels including the enteric flora, scientifically known as "microbiota," and the inside of the body. These cells are not only responsible for absorbing nutrients and drugs; their metabolism has an effect on various functions in all parts of the body."Many molecular aspects of nutrient absorption in the intestines are still unknown. We do know, however, that some nutrient transporters also play a role in drug absorption," explained Eva Rath, scientist at the Chair of Nutrition and Immunology at TUM.In their latest publication, the researchers illustrate how the transport of nutrients and drugs and the subsequent metabolic changes can be measured in organoids. "This paves the way for this model to be used in medical and pharmaceutical applications such as drug screening," Rath added."When studying diseases or performing drug screenings, it is critical to have access to a human test system such as human organoids in order to prevent obtaining species specific test results," said Tamara Zietek, who is part of the Chair of Nutritional Physiology at TUM.She added that, "over the course of the last few years, organoids have become one of the most promising in vitro models due to their high physiological relevance; they also present a human-based alternative method to animal experiments."The processes established by the research team are of particular importance for both fundamental research and drug development, but also regarding regulation in terms of safety testing for chemicals and other agents.
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Zoology
| 2,020 |
October 12, 2020
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https://www.sciencedaily.com/releases/2020/10/201012103146.htm
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Ancient tiny teeth reveal first mammals lived more like reptiles
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Pioneering analysis of 200 million-year-old teeth belonging to the earliest mammals suggests they functioned like their cold-blooded counterparts -- reptiles, leading less active but much longer lives.
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The research, led by the University of Bristol, UK and University of Helsinki, Finland, published today in Fossils of teeth, the size of a pinhead, from two of the earliest mammals, Morganucodon and Kuehneotherium, were scanned for the first time using powerful X-rays, shedding new light on the lifespan and evolution of these small mammals, which roamed the earth alongside early dinosaurs and were believed to be warm-blooded by many scientists. This allowed the team to study growth rings in their tooth sockets, deposited every year like tree rings, which could be counted to tell us how long these animals lived. The results indicated a maximum lifespan of up to 14 years -- much older than their similarly sized furry successors such as mice and shrews, which tend to only survive a year or two in the wild."We made some amazing and very surprising discoveries. It was thought the key characteristics of mammals, including their warm-bloodedness, evolved at around the same time," said lead author Dr Elis Newham, Research Associate at the University of Bristol, and previously PhD student at the University of Southampton during the time when this study was conducted."By contrast, our findings clearly show that, although they had bigger brains and more advanced behaviour, they didn't live fast and die young but led a slower-paced, longer life akin to those of small reptiles, like lizards."Using advanced imaging technology in this way was the brainchild of Dr Newham's supervisor Dr Pam Gill, Senior Research Associate at the University of Bristol and Scientific Associate at the Natural History Museum London, who was determined to get to the root of its potential."A colleague, one of the co-authors, had a tooth removed and told me they wanted to get it X-rayed, because it can tell all sorts of things about your life history. That got me wondering whether we could do the same to learn more about ancient mammals," Dr Gill said.By scanning the fossilised cementum, the material which locks the tooth roots into their socket in the gum and continues growing throughout life, Dr Gill hoped the preservation would be clear enough to determine the mammal's lifespan.To test the theory, an ancient tooth specimen belonging to Morganucodon was sent to Dr Ian Corfe, from the University of Helsinki and the Geological Survey of Finland, who scanned it using high-powered Synchrotron X-ray radiation."To our delight, although the cementum is only a fraction of a millimetre thick, the image from the scan was so clear the rings could literally be counted," Dr Corfe said.It marked the start of a six-year international study, which focused on these first mammals, Morganucodon and Kuehneotherium, known from Jurassic rocks in South Wales, UK, dating back nearly 200 million years."The little mammals fell into caves and holes in the rock, where their skeletons, including their teeth, fossilised. Thanks to the incredible preservation of these tiny fragments, we were able to examine hundreds of individuals of a species, giving greater confidence in the results than might be expected from fossils so old," Dr Corfe added.The journey saw the researchers take some 200 teeth specimens, provided by the Natural History Museum London and University Museum of Zoology Cambridge, to be scanned at the European Synchrotron Radiation Facility and the Swiss Light Source, among the world's brightest X-ray light sources, in France and Switzerland, respectively.In search of an exciting project, Dr Newham took this up for the MSc in Palaeobiology at the University of Bristol, and then a PhD at the University of Southampton."I was looking for something big to get my teeth into and this more than fitted the bill. The scanning alone took over a week and we ran 24-hour shifts to get it all done. It was an extraordinary experience, and when the images started coming through, we knew we were onto something," Dr Newham said.Dr Newham was the first to analyse the cementum layers and pick up on their huge significance."We digitally reconstructed the tooth roots in 3-D and these showed that Morganucodon lived for up to 14 years, and Kuehneotherium for up to nine years. I was dumbfounded as these lifespans were much longer than the one to three years we anticipated for tiny mammals of the same size," Dr Newham said."They were otherwise quite mammal-like in their skeletons, skulls and teeth. They had specialised chewing teeth, relatively large brains and probably had hair, but their long lifespan shows they were living life at more of a reptilian pace than a mammalian one. There is good evidence that the ancestors of mammals began to become increasingly warm-blooded from the Late Permian, more than 270 million years ago, but, even 70 million years later, our ancestors were still functioning more like modern reptiles than mammals"While their pace-of-life remained reptilian, evidence for an intermediate ability for sustained exercise was found in the bone tissue of these early mammals. As a living tissue, bone contains fat and blood vessels. The diameter of these blood vessels can reveal the maximum possible blood flow available to an animal, critical for activities such as foraging and hunting.Dr Newham said: "We found that in the thigh bones of Morganucodon, the blood vessels had flow rates a little higher than in lizards of the same size, but much lower than in modern mammals. This suggests these early mammals were active for longer than small reptiles but could not live the energetic lifestyles of living mammals."
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Zoology
| 2,020 |
October 8, 2020
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https://www.sciencedaily.com/releases/2020/10/201008142108.htm
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There's a gene for detecting that fishy smell, olfactory GWAS shows
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For many people, the smell of fish is rather strong and unpleasant. But some people carry a mutation in a particular gene that makes that fish odor less intense, reports a paper publishing October 8 in the journal
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"We discovered sequence variants that influence how we perceive and describe fish, licorice, and cinnamon odors," said Rosa Gisladottir of deCODE Genetics in Reykjavik, Iceland. "Since our sense of smell is very important for the perception of flavor, these variants likely influence whether we like food containing these odors."Researchers have known that people perceive odors based on olfactory receptors encoded by 855 olfactory genes. But about half of those genes in people are thought to lack function, leaving us with a relatively small repertoire of about 400 olfactory genes. The reason humans have lost so many olfactory genes has remained mysterious. It is also not well understood how variation in these genes might influence differences among people in their sense of smell.To explore this in the new study, Gisladottir and her colleagues including Kari Stefansson, also of deCODE, enlisted 9,122 Icelanders in a GWAS in search of variants that influence odor perception. To do it, they asked study participants to smell odors presented to them in pen-like devices that released a particular scent when uncapped. After sniffing each odor "pen," the researchers asked them to name the smell. Participants also rated the intensity and pleasantness of the smell. Those odors included key ingredients found in licorice, cinnamon, fish, lemon, peppermint, and banana.Their search turned up variants in three genes or genetic loci of interest, which they were able to confirm in a separate sample of 2,204 Icelanders. One of them is in a non-canonical olfactory receptor gene called trace amine-associated receptor 5 (TAAR5). The TAAR5 variant affects perception of fish odor containing trimethylamine, a compound found in rotten and fermented fish, as well as other animal odors and various bodily secretions. In the smell tests, people with a particular variant of this gene were more likely to not smell anything when presented with the fish odor or to use descriptors for it that were neutral or positive and not seafood related, such as "potatoes," "caramel," and "rose." The findings are the first to show an important role for this gene in people, the researchers say."Carriers of the variant find the fish odor less intense, less unpleasant, and are less likely to name it accurately," Gisladottir said. "There is a lot of animal research on TAAR5 in relation to its role in hard-wired aversive responses to trimethylamine. Our findings extend the implications of this research to human odor perception and behavior."The other two discoveries were found in more typical and common olfactory gene variants. They influenced an individual's ability to name licorice and cinnamon odors. They also influenced the intensity and pleasantness associated with those odors."We discovered a common variant in a cluster of olfactory receptors which is associated with increased sensitivity to trans-anethole, found in black licorice products but also in spices and plants such as anise seed, star anise, and fennel," Gisladottir said. "Carriers of the variant find the licorice odor more intense, more pleasant, and can name it more accurately. Interestingly, the variant is much more common in East Asia than in Europe."The cinnamon variant influenced the perception of trans-cinnamaldehyde, the major ingredient in both Chinese and Ceylon cinnamon. Carriers of the variant can name the cinnamon odor more accurately, they report. They also find it more intense.Overall, the findings show that variation in olfactory genes influences odor perception in humans. They also show that, while humans have fewer olfactory genes compared to other species, some of the genetic variation that people do carry makes them more sensitive to particular smells such as licorice or cinnamon, not less."When coupled with evidence for geographical differences in allele frequencies, this raises the possibility that the portion of the extensive sequence diversity found in human olfactory receptor genes that affects our sense of smell is still being honed by natural selection," the researchers wrote.The researchers say they will continue to collect data on odor perception in people. They also plan to use the same olfactory tasks to investigate smell deficits in the context of COVID-19.
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Zoology
| 2,020 |
October 8, 2020
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https://www.sciencedaily.com/releases/2020/10/201008104257.htm
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Airdropping sensors from moths
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There are many places in this world that are hard for researchers to study, mainly because it's too dangerous for people to get there.
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Now University of Washington researchers have created one potential solution: A 98 milligram sensor system -- about one tenth the weight of a jellybean, or less than one hundredth of an ounce -- that can ride aboard a small drone or an insect, such as a moth, until it gets to its destination. Then, when a researcher sends a Bluetooth command, the sensor is released from its perch and can fall up to 72 feet -- from about the sixth floor of a building -- and land without breaking. Once on the ground, the sensor can collect data, such as temperature or humidity, for almost three years.The team presented this research Sept. 24 at MobiCom 2020."We have seen examples of how the military drops food and essential supplies from helicopters in disaster zones. We were inspired by this and asked the question: Can we use a similar method to map out conditions in regions that are too small or too dangerous for a person to go to?" said senior author Shyam Gollakota, a UW associate professor in the Paul G. Allen School of Computer Science & Engineering. "This is the first time anyone has shown that sensors can be released from tiny drones or insects such as moths, which can traverse through narrow spaces better than any drone and sustain much longer flights."While industrial-sized drones use grippers to carry their payloads, the sensor is held on the drone or insect using a magnetic pin surrounded by a thin coil of wire. To release the sensor, a researcher on the ground sends a wireless command that creates a current through the coil to generate a magnetic field. The magnetic field makes the magnetic pin pop out of place and sends the sensor on its way.The sensor was designed with its battery, the heaviest part, in one corner. As the sensor falls, it begins rotating around the corner with the battery, generating additional drag force and slowing its descent. That, combined with the sensor's low weight, keeps its maximum fall speed at around 11 miles per hour, allowing the sensor to hit the ground safely.The researchers envision using this system to create a sensor network within a study area. For example, researchers could use drones or insects to scatter sensors across a forest or farm that they want to monitor.Once a mechanism is developed to recover sensors after their batteries have died, the team expects their system could be used in a wide variety of locations, including environmentally sensitive areas. The researchers plan to replace the battery with a solar cell and automate sensor deployment in industrial settings.
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Zoology
| 2,020 |
October 7, 2020
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https://www.sciencedaily.com/releases/2020/10/201007145301.htm
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Boosting chickens' own immune response could curb disease
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Broiler chicken producers the world over are all too familiar with coccidiosis, a parasite-borne intestinal disease that stalls growth and winnows flocks. Various approaches, developed over decades, have been used to control coccidiosis, but the disease remains widespread.
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Recent research from the University of Illinois supports the use of immunomodulatory and antioxidant feed additives to reduce the effects of coccidiosis."In the last two decades, partially to get around the parasite's resistance to pharmaceuticals, vaccination has become more prevalent. That's when I got interested, because nutrition is a key element in the effectiveness of vaccines. Diet and health go together in that way," says Ryan Dilger, associate professor in the Department of Animal Sciences at Illinois and principal investigator on the research. "So, what we're talking about here is not a vaccine. Instead, we used nutritional technologies to disrupt the normal reproductive cycle of the parasite."When a chicken picks up the parasite, of which there are seven major Eimeria species affecting broilers, its body mounts an immune response, starting with a cascade of inflammatory proteins known as cytokines. These cause the bird to stop eating and rest, so the immune system can do its work. In normal disease progression, an anti-inflammatory mediator known as interleukin-10 (IL-10) is eventually produced to keep the inflammation from ramping up too high and causing tissue damage through oxidative stress.However, Eimeria tricks chickens into over-producing IL-10 earlier than expected, before the immune system can produce enough cytokines to effectively attack the invader. "It's like the parasite is saying, 'Everything's fine. I'm not actually here!' It's really trying to evade the immune response," Dilger says.To reverse that effect, doctoral student Muhammed Shameer Abdul Rasheed included a novel feed ingredient, a dried egg product with IL-10 antibody activity, in the diet of broiler chickens before inducing coccidiosis."We want the bird to have an acute pro-inflammatory response in order to clear the parasite, and that response is dampened when the parasite tricks the bird into overproducing IL-10 antibody. We're trying to take away the parasite's ability to manipulate the bird's own immune system against itself," Rasheed says.The IL-10 dried egg product has been shown to be effective against mild Eimeria infection in other studies, but it hadn't been tested in severe cases and in the absence of vaccine administration."Our results suggested that dietary dried egg product could be beneficial in promoting gut health during severe infection for particular strains of the parasite, even though suppression of the IL-10 response may promote an exaggerated inflammatory reaction in the intestinal epithelium, which may cause subsequent tissue damage," Dilger says.Uncontrolled inflammatory responses can lead to oxidative stress, where chemicals with unpaired electrons, known as free radicals, start to damage healthy tissue. When Rasheed saw the intestinal damage in this study, he decided to test the combined effects of the IL-10 antibody and an antioxidant known as methylsulfonylmethane or MSM. He had previously tested MSM in chickens and found it had no adverse effects on health or growth, but it had never been tried as a treatment for oxidative stress during coccidiosis."The IL-10 antibody works to combat the infection through an immune mechanism, which may inadvertently cause oxidative stress, so MSM was used in combination to specifically combat that tissue damage," Rasheed says. "So the hypothesis was that if these two interventions are working through different mechanisms, combining them together may actually give us a better response than either of them alone."When the research team fed infected birds a combination of MSM and IL-10 antibody, the treatment showed promise. First, chickens that got the treatment showed greater body weight gain 7-14 days post-infection than birds that didn't consume the dietary products. Also, total antioxidant capacity, an overall indicator of how well an animal can counteract oxidative stress, remained higher in treated birds three and four weeks after infection, suggesting lasting dietary effects."In the end, the birds still got sick; they still had an infection that reduced their growth for a certain amount of time. Just like with some pharmaceutical agents designed to lessen the effects of the flu in humans, it's not actually going to prevent you from getting the disease in the first place. However, our goal is to shorten the length of time you're sick," Dilger says. "That's just as meaningful for broiler chickens."Dilger thinks the dietary interventions may be even more effective in real-world production settings. In the clean, controlled environment of a laboratory study, these broiler chickens were raised on wire flooring to separate the birds from their excrement. However, broiler chickens raised on a commercial farm would be raised on the floor, in direct contact with litter, which is partly how the Eimeria infection cycle continues. In the end, the nutritional strategies studied here may act as a kind of insurance for producers to help birds bounce back sooner."Producers may not have coccidiosis when they mix this in the feed, but by the time the chickens consume it, the disease may have reared up again. So if the product is already there, you have some protection," Dilger says. "Again, it's not going to prevent the birds from getting coccidiosis, but hopefully it can reduce the untoward effects and allow them to get back to a healthy state faster and continue growing, such that they can remain productive during that time. It's another important tool in the arsenal for producers."
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Zoology
| 2,020 |
October 7, 2020
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https://www.sciencedaily.com/releases/2020/10/201007123057.htm
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Invisible threat: Listeria in smoked fish
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In 2018, 701 cases of severe invasive listeriosis were communicated to the Robert Koch Institute (RKI), which translates into 0.8 cases per 100,000 inhabitants. Most listeriosis illnesses reported are severe and are associated with blood poisoning, meningitis or miscarriages, for example. In 2018, the disease was fatal in 5% of cases. Elderly people, people with weakened immune defences, pregnant women and their new-born babies are particularly vulnerable. Listeria can be found in a large variety of foods of plant and animal origin. Cold or hot-smoked fish are often contaminated and are, therefore, also suspected of transmitting this illness. Other fish products and seafood eaten raw, such as sushi, sashimi and oysters or cured products such as graved fish, may also be affected. "Pregnant women, elderly people or those with weakened immune defences should only eat fish and seafood that have been thoroughly heated," says BfR President Professor Dr. Dr. Andreas Hensel.
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Not all Listeria bacteria cause illness. Of the 20 Listeria species described, only Listeria (L.) monocytogenes is a significant cause of infection in humans. Infections during pregnancy can lead to miscarriage, premature birth, stillbirth or the birth of a sick child. Furthermore, listeriosis mainly develops in people whose immune system is weakened by old age, pre-existing medical conditions or medication intake. They often suffer from blood poisoning, encephalitis or meningitis as well as e.g. from endocarditis or bacterial joint inflammation. Listeriosis is associated with relatively high mortality in risk groups. In healthy individuals who do not belong to one of the risk groups, an infection can lead to inflammation of the gastrointestinal tract plus a fever, with progression generally being mild.The bacterium L. monocytogenes is widespread in the environment and can be found in many foods. High detection rates are found in minced meat, raw meat dishes (e.g. tartare), raw sausage meat (e.g. "Mettwurst" raw minced pork) and raw milk, for example. However, numerous other ready-to-eat foods of animal and plant origin, which are not subjected to further germicidal treatment (e.g. heating) after processing, may also contain L. monocytogenes. Examples include cheese (made from raw or pasteurised milk), pre-cut salads and vegetables, deli salads or sliced sausage products. This is because listeria can survive for a long time in food processing plants in recesses that are difficult to reach for cleaning and disinfection. As a result, the continuous entry of the germs during food production is possible.Raw, smoked or cured fish products and seafood such as sushi, sashimi, oysters, cold or hot smoked fish (e.g. smoked salmon) and cured fish (e.g. graved salmon) are frequently contaminated with listeria. 7 to 18 % of the samples of cold-smoked or cured fish products examined by the food monitoring authorities in Germany between 2007 and 2017, and 3 to 9 % of the samples of hot-smoked fish products contained L. monocytogenes. Even low germ concentrations are hazardous to risk groups, for example when products are stored at home above the temperatures recommended by the manufacturer or when they are eaten after their best-before date. What's more, handling contaminated products risks transferring listeria to other foods.The German Nutrition Society (DGE) recommends at least one fish meal every week. Fish notably contains special fatty acids and the long-chain omega-3 fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA).The BfR recommends that people who have an increased risk of developing listeriosis should not generally avoid fish, but rather only eat fish or seafood that has been thoroughly heated. Listeria can be reliably killed off by heating food to a core temperature of 70 °C for at least two minutes. Risk groups should refrain from eating raw, smoked and cured fish products and seafood.
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Zoology
| 2,020 |
October 7, 2020
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https://www.sciencedaily.com/releases/2020/10/201007123025.htm
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Aerodynamicists reveal link between fish scales and aircraft drag
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The team's findings have been published in
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Reducing drag means faster aircraft speeds and less fuel consumption -- an important area of study for aerodynamicists such as Professor Bruecker, City's Royal Academy of Engineering Research Chair in Nature-Inspired Sensing and Flow Control for Sustainable Transport, and City's Sir Richard Oliver BAE Systems Chair for Aeronautical Engineering.Through their biomimetic study, Professor Bruecker's team has discovered that the fish-scale array produces a zig-zag motion of fluid in overlapping regions of the surface of the fish, which in turn causes periodic velocity modulation and a streaky flow that can eliminate Tollmien-Schlichting wave induced transition to reduce skin friction drag by more than 25 percent.An examination of oil flow visualisation using computational fluid dynamics (CFD) on sea bass and common carp enabled the authors to come up with a working hypothesis:"Computation Fluid Dynamics (CFD) was used to study the flow pattern over the surface and revealed a hitherto unknown effect of the scales as a mechanism to generate a regular pattern of parallel streamwise velocity streaks in the boundary layer. To prove their existence also on the real fish skin, oil flow visualisation was done on sea bass and common carp, which indeed confirmed their presence in a regular manner along their real body, with the same arrangement relative to the scale array as observed along the biomimetic surface. These results let the authors hypothesize about a possible mechanism for transition delay, inspired by various previous fundamental transition studies, where streaky structures generated by cylindrical roughness elements or vortex generator arrays have shown a delay of transition."Using the specially equipped laminar water tunnel at the University of Stuttgart in Germany, Professor Bruecker and Professor Rist (University of Stuttgart) have tested the hypothesis of a transition (drag) delay by experimenting with a smooth flat plate and a flat plate covered with biomimetic fish scale arrays.Their surprising research outcome runs counter to the common belief that roughness promotes by-pass transition. Instead, the scales largely increase the stability of the base flow similar to an array of vortex generators.A technical realisation of such patterns on aerodynamic surfaces will pave the way towards the drastic reduction in fuel consumption and future zero-emission flight.
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Zoology
| 2,020 |
October 6, 2020
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https://www.sciencedaily.com/releases/2020/10/201006165746.htm
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This 'squidbot' jets around and takes pics of coral and fish
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Engineers at the University of California San Diego have built a squid-like robot that can swim untethered, propelling itself by generating jets of water. The robot carries its own power source inside its body. It can also carry a sensor, such as a camera, for underwater exploration.
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The researchers detail their work in a recent issue of "Essentially, we recreated all the key features that squids use for high-speed swimming," said Michael T. Tolley, one of the paper's senior authors and a professor in the Department of Mechanical and Aerospace Engineering at UC San Diego. "This is the first untethered robot that can generate jet pulses for rapid locomotion like the squid and can achieve these jet pulses by changing its body shape, which improves swimming efficiency."This squid robot is made mostly from soft materials such as acrylic polymer, with a few rigid, 3D printed and laser cut parts. Using soft robots in underwater exploration is important to protect fish and coral, which could be damaged by rigid robots. But soft robots tend to move slowly and have difficulty maneuvering.The research team, which includes roboticists and experts in computer simulations as well as experimental fluid dynamics, turned to cephalopods as a good model to solve some of these issues. Squid, for example, can reach the fastest speeds of any aquatic invertebrates thanks to a jet propulsion mechanism.Their robot takes a volume of water into its body while storing elastic energy in its skin and flexible ribs. It then releases this energy by compressing its body and generates a jet of water to propel itself.At rest, the squid robot is shaped roughly like a paper lantern, and has flexible ribs, which act like springs, along its sides. The ribs are connected to two circular plates at each end of the robot. One of them is connected to a nozzle that both takes in water and ejects it when the robot's body contracts. The other plate can carry a water-proof camera or a different type of sensor.Engineers first tested the robot in a water testbed in the lab of Professor Geno Pawlak, in the UC San Diego Department of Mechanical and Aerospace Engineering. Then they took it out for a swim in one of the tanks at the UC San Diego Birch Aquarium at the Scripps Institution of Oceanography.They demonstrated that the robot could steer by adjusting the direction of the nozzle. As with any underwater robot, waterproofing was a key concern for electrical components such as the battery and camera.They clocked the robot's speed at about 18 to 32 centimeters per second (roughly half a mile per hour), which is faster than most other soft robots."After we were able to optimize the design of the robot so that it would swim in a tank in the lab, it was especially exciting to see that the robot was able to successfully swim in a large aquarium among coral and fish, demonstrating its feasibility for real-world applications," said Caleb Christianson, who led the study as part of his Ph.D. work in Tolley's research group. He is now a senior medical devices engineering at San Diego-based Dexcom.Researchers conducted several experiments to find the optimal size and shape for the nozzle that would propel the robot. This in turn helped them increase the robot's efficiency and its ability to maneuver and go faster. This was done mostly by simulating this kind of jet propulsion, work that was led by Professor Qiang Zhu and his team in the Department of Structural Engineering at UC San Diego. The team also learned more about how energy can be stored in the elastic component of the robot's body and skin, which is later released to generate a jet.Video:
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Zoology
| 2,020 |
October 6, 2020
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https://www.sciencedaily.com/releases/2020/10/201006114237.htm
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Sprat, mollusks and algae: What a diet of the future might look like
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At a time when food production is one of the biggest climate culprits, it is essential that we seek out new food sources which can nourish us and, at the same time, not overburden the planet.
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More and more people are opting to become vegetarians or, even more radically, vegans.However, the large majority of people find it difficult to entirely shelve meat in the name of preventing climate change, according to Professor Ole G. Mouritsen of the University of Copenhagen's Department of Food Science."Many people simply crave the umami flavor that is, for example, found in meat. Therefore, it may be more realistic to consider a flexitarian diet, where one consumes small quantities of animal products, such as meat, eggs and milk, alongside vegetables. However, one can also begin thinking about alternatives to the juicy steak -- of which there are many," he says.In a new meta-study, Professor Mouritsen and PhD student Charlotte Vinther, his colleague at the Department of Food Science, pick up on today's food trends.They present alternative sources for protein and healthy fatty acids, while giving their take on what a sustainable diet of the future might look like.Among other things, the researchers recommend that we look to the sea for foods of the future.More specifically, we need to get to the bottom, where species typically associated with being bycatch and industrial fish live. These species emit far less CO"The climate-friendly bycatch fish currently used for pig feed or fish oil live near the bottom of the ocean. They include: sand lance, a fish which digs into the sandy bottom to lay eggs; sprat, a relative of herring which is widespread in Danish waters; and the black-mouthed gobi, another small, but tasty and overlooked fish," explains Mouritsen.Sprat alone could satisfy 20 percent of Denmark's protein needs. And by fishing for sprat, we can avoid the over-exploitation of more well-known fish species such as cod, plaice and salmon, explains the professor.Seaweed and algae are also an overlooked and extremely climate-friendly food source.However, only 500 of 10,000 species are currently exploited and recognized as food -- despite the fact that marine algae are packed with incredibly healthy nutrients and vitamins.Similarly, cephalopods are only fished to a small extent, with 30 out of approximately 800 species being used for food globally."Among other things, this has much to do with our culture and traditions. Food consumption habits take time to change. We have been eating and preparing meat for more than a million years. So even though seaweed, squid and mollusks contain important fatty acids and vitamins, and can taste great, we remain reluctant to count these species among our food sources," says Ole G. Mouritsen.One possible explanation for the fact that we find it difficult to green our diet is that we have an innate preference for sweetness and foods with an umami flavor. According to the professor:"Sweetness signals calories and survival to the brain, and umami signals that we are consuming something good for our muscles. However, many seafoods, marine algae and vegetables have the potential to taste great, and that's something that we can use technology to help develop."For example, by fermenting or adding enzymes to vegetables, sweet and umami tastes can be brought out, says Ole G. Mouritsen."Several Asian food producers have something called 'shio-koji', which can also be made at home. Koji is a salty solution of dead microscopic fungi with active enzymes. By adding it to sliced broccoli and putting them in the fridge for a few hours, you'll be able to taste more sweetness and umami in the pieces of vegetable," he says, concluding:"It is essential that we continue to communicate these new opportunities to eat sustainably. By doing so, we will gradually effectuate change upon our eating habits and traditions. We hope that this study plays a part."
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Zoology
| 2,020 |
October 5, 2020
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https://www.sciencedaily.com/releases/2020/10/201005112142.htm
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High throughput screening identifies molecules that reduce cellular stress
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For many, getting older can unfortunately mean an increased risk of illness from cardiovascular disease to cancer. University of Michigan scientists are actively researching the biological underpinnings of aging with the aim of developing interventions that could potentially help people live longer, healthier lives.
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A new paper in the journal Science Advances describes the discovery of several promising small molecules that appear to reduce cellular stress in mouse skin cells and could lengthen life."Cellular stress resistance appears to be a common feature of long-lived organisms, such as invertebrates and mice," says the paper's lead author David Lombard, M.D., Ph.D., associate professor of pathology. Lombard is part of a multidisciplinary group at U-M's Paul F. Glenn Center for Aging. Recent research from colleague and fellow study author Richard Miller, M.D., Ph.D., found several promising drugs, including rapamycin, a cancer drug, and acarbose, a diabetes drug, that extended life in mice.The new study, which uses high throughput screening, a technique that allows for the examination of hundreds of compounds at once, gets around some of the limitations posed by mouse studies."Mice live on average three years, which makes using them for longevity studies time-consuming and expensive," Lombard explains. By using cells to examine how a cell responds to stress, they hope to develop a proxy system with which to look at aging.For the study, mouse skin cells were exposed to three types of environmental stress: a toxic herbicide called paraquat, the heavy metal cadmium and methyl methansulfonate, which damages DNA. After treatment with more than 4500 compounds, the team identified hundreds of small molecules that conferred some degree of protection against one or more of the stressors. The team then focused on eight compounds for a closer examination of how they worked at the molecular level.Lombard explains that two candidates, AEG 3482 and cardamonin (found in spices such as cardamom), appeared to activate the Nrf2/SKN-1 pathway. Previous research has shown that this pathway helps cells resist stress and is implicated in the life-lengthening effects of several other interventions in C. elegans, a worm frequently used for aging studies, and can even extend the lifespan of male mice.Comparing their findings to a different study of longevity in C. elegans, they found some of the same compounds that protected worms from stress were of the same class as those that their team identified as effective in mouse cells.The team notes that their method has limitations. For example, they found that rapamycin and acarbose, previously shown to extend life in mice, did not protect against the stressors they used. And, says Lombard, a lot more work needs to occur before the findings can be extrapolated to humans. "I think the bottom line is we're fairly different than worms and flies, and some of these drugs have similar effects in different organisms, but it's not a one to one relationship."Lombard says the promise of the method is its ability to find interesting drugs for follow up, especially to study their mechanism of action. "I don't think any are ready for lifespan studies, but what we've identified is an interesting group of compounds that have some intriguing effects in cells and in invertebrates."
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Zoology
| 2,020 |
October 1, 2020
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https://www.sciencedaily.com/releases/2020/10/201001200238.htm
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More crickets and katydids 'singing in the suburbs'
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The songs that crickets and katydids sing at night to attract mates can help in monitoring and mapping their populations, according to Penn State researchers, whose study of Orthoptera species in central Pennsylvania also shed light on these insects' habitat preferences.
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"We were surprised to find more species in suburban areas than in either urban or rural areas," said the study's lead researcher, D.J. McNeil, postdoctoral fellow in Penn State's Insect Biodiversity Center and the Department of Entomology.The study was the first to show that the use of aural point count surveys -- a method commonly used by wildlife biologists to study birds and other vertebrates by listening to their songs -- can be effective in exploring the population dynamics of night-singing insect species, the researchers said."Insect populations are showing declines globally, and several studies have indicated that Orthopterans, such as grasshoppers, crickets and katydids, are among the most threatened insect groups," said study co-author Christina Grozinger, Publius Vergilius Maro Professor of Entomology, Penn State College of Agricultural Sciences. "Having a nondestructive way to monitor and map these species is vital for understanding how to conserve and expand their populations."McNeil explained that Orthoptera species -- such as those in suborder Ensifera, which consists of crickets and katydids -- are known to be highly sensitive to variation in habitat conditions. Since they feed on plants, these species also can be affected negatively when insecticides and herbicides are applied to vegetation.McNeil noted that few efficient, standardized monitoring protocols exist for Ensifera, and many involve lethal trapping or time-intensive collection efforts such as mark-recapture. In addition, other collection methods such as sweep-netting are challenging in densely vegetated habitats, especially for katydid species, many of which live high in trees. The researchers pointed out that the conspicuous stridulations, or mating calls, produced by singing Ensifera make them excellent candidates for aural population surveys."Although researchers have used acoustic sampling methods for crickets and katydids in the past, these methods often require specialized audio gear and complex machine-learning algorithms to disentangle the insects' calls from the background noise," McNeil said. "This is very expensive, and it requires a very high-tech skill set. Developing a simple and efficient monitoring protocol can greatly improve our ability to study and understand Ensifera population ecology."To address this need, McNeil drew on his background in ornithology -- his doctoral research focused on birds -- to develop a protocol that required only a human being to conduct aural point count surveys."You can identify birds by their calls really easily, and I came to realize that this was true for crickets and katydids," he said. "For example, one cricket species makes a particular type of chirp, and another one has a different pattern. So, over the course of a few years, I've taught myself the different breeding calls of the crickets and katydids, and I've reached the point where I can confidently identify a large portion of the species that we have in this region."The researchers defined the study area by selecting a central point in downtown State College, Pennsylvania, and plotting four transects extending 10 kilometers east, west, north and south. Along each transect, they selected 10 points, about 1 km apart, as survey locations. The resulting 41 roadside sampling points encompassed deciduous forest, row-crop agricultural fields, pastures, and varying degrees of urban and suburban cover types."That allowed us not only to get different habitat types, but to capture a smooth gradient across the entire spectrum of what a cricket might experience," McNeil said.McNeil conducted all of the surveys by standing stationary for three minutes at each location and using a checklist to record the number of Ensifera species detected. Because the study focused on crickets and katydids that sing mostly after dark, sampling was performed between sunset and midnight, and each location was sampled five times from July to November in 2019, a time of year that includes the seasonal singing periods for most local Ensifera. He then used occupancy modeling approaches to map the species distributions across the urban-to-rural gradient.The findings, reported Sept. 29 in the "We found that intermediate levels of urbanization, such as what you'd find in suburban areas, hosted the highest number of species, perhaps because areas with intermediate levels of disturbance host the greatest number of habitat niches and can support more species than heavily disturbed or totally undisturbed ecosystems," McNeil said."We hope that this study inspires people to listen carefully to the diverse insect songs in their backyards at night and think about ways to improve the habitat for these important species," Grozinger said.
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Zoology
| 2,020 |
October 1, 2020
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https://www.sciencedaily.com/releases/2020/10/201001113638.htm
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Survey finds American support for human-animal chimera research
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In September 2015, the US National Institutes of Health placed a funding moratorium on research that involves introducing human pluripotent stem cells into animal embryos -- a practice that experts say is vital for advancing the field of regenerative medicine. To assess attitudes on human-animal chimeric embryo research, investigators conducted a survey among 430 Americans. The results of the survey, which found that 82% of people are supportive of at least some parts of this research, appear October 1 in the journal
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"The take-home point is that the overall support for this kind of research across the American public is strong," says co-author Francis Shen, a professor of law at the University of Minnesota and executive director of the Harvard Massachusetts General Hospital Center for Law, Brain, and Behavior. "I think this speaks to the public's interest in the transformative potential of regenerative medicine for addressing disease in a variety of organs.""Public attitudes were more supportive than I thought would have been possible in the current political climate," says first author Andrew Crane, a researcher in the Department of Neurosurgery at the University of Minnesota.Crane and senior author Walter Low, a professor in the Department of Neurosurgery and Stem Cell Institute at the University of Minnesota, conduct research on stem cell applications for neurological disorders like Parkinson's disease. One project focuses on generating human neural stem cells within pig brains. After learning that colleagues in Japan had done a survey on public attitudes about this type of research, they decided to conduct a similar study in the United States. Low and Crane began a collaboration with the Japan group and with Shen, who specializes in ethics at the intersection of law and neuroscience.The study included two waves of data collection: 227 participants were surveyed in July 2018 and 203 additional participants were surveyed in June 2020. The participants were recruited through an Amazon service called Mechanical Turk and were paid $1 for completing the survey. The questions in the survey were similar to those included in the Japanese study.The participants knew "next to nothing "about this research going into the survey, Shen explains. "We used images, and we clarified how this research might be done, breaking it down into steps."The survey questions were designed to assess opinions on the progressive steps of human-animal chimeric embryo research, by asking participants which aspects of research they were willing to accept based on their personal feelings. For example, it included scenarios about first injecting human stem cells into a pig embryo, then transplanting that embryo into a pig uterus to produce a pig with a human organ, and finally transplanting that organ into a human patient. It also broke down research by organ, with support for some tissue types being higher than others: 61% for heart, 64% for blood, 73% for liver, and 62% for skin, versus 44% for sperm/eggs and 51% for brain."With regard to putting human brain cells into animal brains, we've heard concerns about the animals having some sort of human consciousness, but that's quite far off from where the science is right now and from anything that we've tried to advocate for in our research," Crane says. "We understand this is a concern that should not be taken lightly, but it shouldn't prohibit us from moving the research forward."The survey was also designed to assess cultural differences, and the researchers were surprised to find that support was relatively high even among religious and cultural conservatives. The largest factor influencing opposition to the research was concern about animal rights."As investigators in the US, we've hit a roadblock with a lot of this research with regard to funding," Crane says. He adds that a lack of funding could lead to the research moving to countries with fewer ethical safeguards in place."The three biggest concerns about this research are animal welfare, human dignity, and the possibility of neurological humanization," Shen concludes. "We would love to do focus groups to look deeper at some of these questions."
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Zoology
| 2,020 |
September 30, 2020
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https://www.sciencedaily.com/releases/2020/09/200930085159.htm
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Dinosaur feather study debunked
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A new study provides substantial evidence that the first fossil feather ever to be discovered does belong to the iconic Archaeopteryx, a bird-like dinosaur named in Germany on this day in 1861. This debunks a recent theory that the fossil feather originated from a different species.
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The research published in "There's been debate for the past 159 years as to whether or not this feather belongs to the same species as the Archaeopteryx skeletons, as well as where on the body it came from and its original color," said lead author Ryan Carney, assistant professor of integrative biology at USF. "Through scientific detective work that combined new techniques with old fossils and literature, we were able to finally solve these centuries-old mysteries."Using a specialized type of electron microscope, the researchers determined that the feather came from the left wing. They also detected melanosomes, which are microscopic pigment structures. After refining their color reconstruction, they found that the feather was entirely matte black, not black and white as another study has claimed.Carney's expertise on Archaeopteryx and diseases led to the National Geographic Society naming him an "Emerging Explorer," an honor that comes with a $10,000 grant for research and exploration. He also teaches a course at USF, called "Digital Dinosaurs." Students digitize, animate and 3D-print fossils, providing valuable experience in paleontology and STEAM fields.
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Zoology
| 2,020 |
September 29, 2020
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https://www.sciencedaily.com/releases/2020/09/200929123354.htm
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Brain circuitry shaped by competition for space as well as genetics
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Complex brain circuits in rodents can organise themselves with genetics playing only a secondary role, according to a new computer modelling study published today in
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The findings help answer a key question about how the brain wires itself during development. They suggest that simple interactions between nerve cells contribute to the development of complex brain circuits, so that a precise genetic blueprint for brain circuitry is unnecessary. This discovery may help scientists better understand disorders that affect brain development and inform new ways to treat conditions that disrupt brain circuits.The circuits that help rodents process sensory information collected by their whiskers are a great example of the complexity of brain wiring. These circuits are organised into cylindrical clusters or 'whisker barrels' that closely match the pattern of whiskers on the animal's face."The brain cells within one whisker barrel become active when its corresponding whisker is touched," explains lead author Sebastian James, Research Associate at the Department of Psychology, University of Sheffield, UK. "This precise mapping between the individual whisker and its brain representation makes the whisker-barrel system ideal for studying brain wiring."James and his colleagues used computer modelling to determine if this pattern of brain wiring could emerge without a precise genetic blueprint. Their simulations showed that, in the cramped quarters of the developing rodent brain, strong competition for space between nerve fibers originating from different whiskers can cause them to concentrate into whisker-specific clusters. The arrangement of these clusters to form a map of the whiskers is assisted by simple patterns of gene expression in the brain tissue.The team also tested their model by seeing if it could recreate the results of experiments that track the effects of a rat losing a whisker on its brain development. "Our simulations demonstrated that the model can be used to accurately test how factors inside and outside of the brain can contribute to the development of cortical fields," says co-author Leah Krubitzer, Professor of Psychology at the University of California, Davis, US.The authors suggest that this and similar computational models could be adapted to study the development of larger, more complex brains, including those of humans."Many of the basic mechanisms of development in the rodent barrel cortex are thought to translate to development in the rest of cortex, and may help inform research into various neurodevelopmental disorders and recovery from brain injuries," concludes senior author Stuart Wilson, Lecturer in Cognitive Neuroscience at the University of Sheffield. "As well as reducing the number of animal experiments needed to understand cortical development, exploring the parameters of computational models like ours can offer new insights into how development and evolution interact to shape the brains of mammals, including ourselves."
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Zoology
| 2,020 |
September 28, 2020
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https://www.sciencedaily.com/releases/2020/09/200928191215.htm
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Study traces the evolution of gill covers
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The emergence of jaws in primitive fish allowed vertebrates to become top predators. What is less appreciated is another evolutionary innovation that may have been just as important for the success of early vertebrates: the formation of covers to protect and pump water over the gills. In a new study published in the
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The scientists started by creating zebrafish with mutations in a gene called Pou3f3. Strikingly, fish lacking this gene, or the DNA element controlling its activity in the gills, failed to form gill covers. Conversely, zebrafish producing too much Pou3f3 developed extra rudimentary gill covers.Intrigued by these findings, co-corresponding authors Gage Crump and Lindsey Barske collaborated with scientists from several universities to explore whether changes in Pou3f3 might account for the wide variation in gill covers across vertebrates. Crump is a professor of stem cell biology and regenerative medicine at the Keck School of Medicine of USC. Barske initiated the study in the Crump Lab, and is now an assistant professor at Cincinnati Children's Hospital Medical Center.In jawless fish such as sea lampreys, which lack gill covers, the scientists found that the control element to produce Pou3f3 in the gill region is missing.In contrast, in cartilaginous fish such as sharks and skates, the control element for Pou3f3 is active in all gills. Correspondingly, nearly all cartilaginous fish have a separate cover over each gill. In bony fish, including zebrafish, the control element produces Pou3f3 in one particular region, leading to a single cover for all gills."Remarkably, we have identified not only a gene responsible for gill cover formation," said Crump, "but also the ancient control element that allowed Pou3f3 to first make gill covers and then diversify them in cartilaginous versus bony fish."Barske and Crump even showed that humans retain this control element, reflecting the presence of gill cover-like structures in human embryos that are inherited from our distant fish ancestors.
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Zoology
| 2,020 |
September 28, 2020
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https://www.sciencedaily.com/releases/2020/09/200928152916.htm
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'Insect Armageddon': Low doses of the insecticide, Imidacloprid, cause blindness in insects
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New research has identified a mechanism by which low levels of insecticides such as, the neonicotinoid Imidacloprid, could harm the nervous, metabolic and immune system of insects, including those that are not pests, such as our leading pollinators, bees.
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A study published today in the With insect populations declining around the world and intense use of insecticides suspected to play a role, the findings provide important evidence that even small doses of insecticides reduce the capacity of insects to survive, even those that are not pests."Our research was conducted on one insecticide, but there is evidence that other insecticides cause oxidative stress, so they may have similar impacts," Professor Philip Batterham, from the School of BioSciences and Bio21 Institute, at the University of Melbourne, said."Our findings emphasize the importance of better understanding the mechanisms of action of insecticides, in particular on beneficial insects. Without further research we do not know if other insecticides are any safer."Imidacloprid, has been banned from agricultural use by the European Union because of concerns about impacts on honeybees, but remains one of the top selling insecticides in the world. Attacking the central nervous systems of the insects, it increases the transmission of stimuli in the insect nervous system, activating receptors resulting in the insect's paralysis and eventual death.The researchers arrived at the findings by studying the effects of Imidacloprid in vinegar fly larvae. In the field, the insecticide is generally used at concentrations of up to 2,800 parts per million (ppm). In the lab, researchers tested lower doses, identifying that the very small dose 2.5 ppm was enough to reduce the movement of fly larvae by 50 percent after just two hours of exposure."That's an indication of the impact of the insecticide on the function of the brain," said Dr Felipe Martelli, whose PhD work conducted at the University of Melbourne and the Baylor College of Medicine in the laboratory of Professor Hugo Bellen led to the current research paper."From there, the accumulation of massive amounts of reactive oxygen species (ROS) or free radicals inside the brain triggers a cascade of damaging events that spread to many other tissues."Researchers also tested the insecticide on adult flies, finding that flies exposed to very low doses (4 ppm) over 25 days became blind and developed movement problems that affected their ability to climb, symptomatic of neurodegeneration in other parts of the brain."Although many studies have shown that low doses of insecticides can affect insect behaviour, they have not uncovered how insecticides trigger changes at the cellular and molecular levels," Dr Martelli, now a research fellow in the School of Biological Sciences at Monash University, said.
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Zoology
| 2,020 |
September 28, 2020
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https://www.sciencedaily.com/releases/2020/09/200928133152.htm
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Evidence that prehistoric flying reptiles probably had feathers refuted
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The debate about when dinosaurs developed feathers has taken a new turn with a paper refuting earlier claims that feathers were also found on dinosaurs' relatives, the flying reptiles called pterosaurs.
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Pterosaur expert Dr David Unwin from the University of Leicester's Centre for Palaeobiology Research, and Professor Dave Martill, of the University of Portsmouth have examined the evidence that these creatures had feathers and believe they were in fact bald.They have responded to a suggestion by a group of his colleagues led by Zixiao Yang that some pterosaur fossils show evidence of feather-like branching filaments, 'protofeathers', on the animal's skin.Dr Yang, from Nanjing University, and colleagues presented their argument in a 2018 paper in the journal While this may seem like academic minutiae, it actually has huge palaeontological implications. Feathered pterosaurs would mean that the very earliest feathers first appeared on an ancestor shared by both pterosaurs and dinosaurs, since it is unlikely that something so complex developed separately in two different groups of animals.This would mean that the very first feather-like elements evolved at least 80 million years earlier than currently thought. It would also suggest that all dinosaurs started out with feathers, or protofeathers but some groups, such as sauropods, subsequently lost them again -- the complete opposite of currently accepted theory.The evidence rests on tiny, hair-like filaments, less than one tenth of a millimetre in diameter, which have been identified in about 30 pterosaur fossils. Among these, Yang and colleagues were only able to find just three specimens on which these filaments seem to exhibit a 'branching structure' typical of protofeathers.Unwin and Martill propose that these are not protofeathers at all but tough fibres which form part of the internal structure of the pterosaur's wing membrane, and that the 'branching' effect may simply be the result of these fibres decaying and unravelling.Dr Unwin said: "The idea of feathered pterosaurs goes back to the nineteenth century but the fossil evidence was then, and still is, very weak. Exceptional claims require exceptional evidence -- we have the former, but not the latter."Professor Martill noted that either way, palaeontologists will have to carefully reappraise ideas about the ecology of these ancient flying reptiles. He said, "If they really did have feathers, how did that make them look, and did they exhibit the same fantastic variety of colours exhibited by birds. And if they didn't have feathers, then how did they keep warm at night, what limits did this have on their geographic range, did they stay away from colder northern climes as most reptiles do today. And how did they thermoregulate? The clues are so cryptic, that we are still a long way from working out just how these amazing animals worked."The paper "No protofeathers on pterosaurs" is published this week in
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Zoology
| 2,020 |
September 28, 2020
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https://www.sciencedaily.com/releases/2020/09/200928125018.htm
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Shorebirds more likely to divorce after successful breeding
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An international team of scientists studying shorebirds, led by the University of Bath, has found that successful plover parents are more likely to divorce after nesting than those that did not successfully breed, in contrast to most other bird species which tend to split up after nest failure.
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The researchers studied the mating behaviour of eight different species of Charadrius plovers, covering 14 populations in different locations across the world.These shorebirds tend to lay 2-4 eggs per nest and can have up to four breeding attempts per season.Plover chicks mature quickly and fly the nest around a month after hatching; in most plover species both parents care for the hatchlings, but in some species either parent can desert the nest to breed again with a new mate.Surprisingly, the researchers found that pairs that successfully raised chicks were more likely to divorce, whereas unsuccessful pairs tended to stick together and try breeding again.Females were more likely to desert the nest than males, and those that did often produced more offspring within a season than parents that retained their mate.Plovers that divorced also dispersed across greater distances between breeding attempts to look for new mates.The findings, published in the journal Naerhulan Halimubieke, PhD student at the Milner Centre for Evolution at the University of Bath and first author of the paper, said: "Our findings go against what you'd intuitively expect to happen -- that divorce would be triggered by low reproductive success."Interestingly, we found that mate fidelity varied amongst different populations of the same species -- for example, Kentish plovers in Europe and China are serial polygamists and are migratory, whereas those found on Cape Verde are exclusively monogamous."This shows that mating behaviour is not simply down to which species they belong, but that other factors affecting the population are also important, such as ratio of males to females and temperature variation of the habitat."Tamás Székely, Professor of Biodiversity at the Milner Centre for Evolution, said: "Our previous work has shown that in populations where there are more females than males, the female tends to leave the nest after breeding to make another nest with a new mate."Since plover chicks don't need much work in bringing them up, one of the parents can free themselves from the nest early and go on to breed elsewhere."Females are more likely to leave their partners if the population is skewed towards males, because they have a greater choice of potential partners and so are more likely to increase their reproductive success by breeding with another mate."More research is needed to fully understand how factors such as the adult sex ratio and the climate of the populations affects the breeding behaviour of these birds."
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Zoology
| 2,020 |
September 25, 2020
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https://www.sciencedaily.com/releases/2020/09/200925113354.htm
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The surprising organization of avian brains
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Some birds can perform amazing cognitive feats -- even though their forebrains seem to just consist of lumps of grey cells, while mammalian forebrains harbour a highly complex neocortex. A study reveals for the first time amazing similarities between the neocortex of mammals and sensory brain areas of birds: both are arranged in horizontal layers and vertical columns.
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These findings refute 150-year-old assumptions. The team, published its findings in the journal Birds and mammals have the largest brains in relation to their body. Apart from that, however, they have little in common, according to scientific opinion since the 19th century: mammalian brains have a neocortex, i.e. a cerebral cortex that's made up of six layers and arranged in columns perpendicular to these layers. Avian brains, on the other hand, look like clumps of grey cells."Considering the astonishing cognitive performance that birds can achieve, it seemed reasonable to suspect that their brains are more organised than expected," says Professor Onur Güntürkün, Head of the Biopsychology Research Unit at the RUB Faculty of Psychology. He and his former doctoral students Dr. Martin Stacho and Dr. Christina Herold proved this in several experiments.In the first step, the researchers deployed a new method perfected by the Düsseldorf and Jülich teams: so-called 3D polarized light imaging, or 3D PLI for short, is capable of displaying the orientation of individual nerve fibres. To the researchers' surprise, an analysis of the brains of various birds revealed an organisation that is similar to that in the mammalian brain: here too, the fibres are arranged horizontally and vertically in the same way as in the neocortex.In further experiments, the researchers used tiny crystals, which are absorbed by nerve cells in brain slices and transport them to their smallest dendrites, to examine the interconnection of cells in the bird brain in detail. "Here, too, the structure was shown to consist of columns, in which signals are transmitted from top to bottom and vice versa, and long horizontal fibres," explains Onur Güntürkün. However, this structure is only found in the sensory areas of the avian brain. Other areas, such as associative areas, are organised in a different way.Some birds are capable of astonishing cognitive performances to rival those of higher developed mammals such as primates. For example, ravens recognise themselves in the mirror and plan for the future. They are also able to put themselves in the position of others, recognise causalities and draw conclusions. Pigeons can learn English spelling up to the level of six-year-old children.The study was funded by the German Research Foundation as part of Collaborative Research Centres 1280 (project no. A01 316803389) and 1372 (project no. Neu04 395940726). Additional funding was supplied by the European Union under the umbrella of the Horizon 2020 Programme (project no. 785907 and 945539).
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Zoology
| 2,020 |
September 25, 2020
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https://www.sciencedaily.com/releases/2020/09/200925113621.htm
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Tracking shape changes in Amazon fish after major river is dammed
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A team of biologists led by Craig Albertson and Ph.D. student Chaise Gilbert at the University of Massachusetts Amherst report this week on their comparison between museum collections of cichlid fishes collected before a dam was closed in 1984 on the Tocantins River in the Amazon and contemporary specimens taken from the Tucuruí Reservoir by fishermen 34 years later.
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Working with others in Brazil, Albertson's team tested the idea that these fish could be expected to show changes in body shape as a consequence to shifts in habitat and foraging behavior after the dam rapidly changed environmental conditions from a clear, flowing river to a deep, murky reservoir."The once-historic rapids and streams that characterized the system have disappeared from the surrounding area, which in turn has affected the abundance and variety of food sources available to native fishes," they write in Cichlid fishes are known in the scientific world for their ability to alter, in as little as a single season, aspects of body shape to match feeding conditions and other changes in the environment, Albertson says. The skeleton is especially sensitive to such environmental inputs, and studying cichlid fishes offers insights into how organisms, in general, may adapt to major human-induced environmental change.Using geometric morphometrics, the researchers evaluated changes in six native species -- from large fish-eating species to small opportunistic omnivores -across five genera representing distinct local varieties whose body shapes reflect their ecological roles.To accomplish this, the researchers used many specimens from fish inventories collected before the dam closure in 1980-1982 now housed in the Instituto Nacional de Pesquisas da Amazônia fish collection, plus even earlier river survey specimens housed now at the Museu de Zoologia da Universidade de São Paulo.Albertson explains, "Our overarching hypothesis is that the damming of the Tocantins and subsequent formation of the Tucuruí reservoir has induced shifts in habitat and foraging behavior and that the anatomy of resident cichlid populations has change in ways that allow them to adapt to this novel environmental conditions. This study represents a first step toward assessing this hypothesis."Gilbert adds, "Was anything surprising? Yes! While we expected to see changes in generalist species -- those that are already predisposed toward living in a variety of habitats -- we were surprised to see shape changes in the specialists as well. Evolving to specialize on a particular prey-type or habitat, can provide a competitive advantage in the near term, but it can also be an evolutionary dead end in the face of a major environmental changes."Not only are these specialist species still found in the area, but they seem to be just as capable of changing body shape as the generalists, the authors report.Albertson reports further thatchanges across all species "tended to be associated with functionally relevant aspects of anatomy, including head, fin and body shape." They found that the regions of the body that changed over time are exactly those most likely to allow them to survive in their new environment, he adds.
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Zoology
| 2,020 |
September 24, 2020
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https://www.sciencedaily.com/releases/2020/09/200924082704.htm
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A new strategy of cell entry for some types of parvoviruses
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Researchers at the Institut national de la recherche scientifique (INRS), in collaboration with American scientists, have uncovered a new parvovirus strategy for reaching the cell nucleus which is their site of replication.
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This new method of entry is a good example of host-driven evolution. Their results were published in the journal However, some types of parvoviruses, as well as other nonenveloped viruses, do not have this enzyme domain and must therefore escape from the vesicle by some other means. Using molecular biology and structural studies, INRS researchers have discovered that a new virus targeting the giant tiger shrimp uses a more mechanical response. This type of parvovirus contains an inner pentamer helix bundle held together by calcium ions. When the microorganism is in the vesicle, where the calcium concentration is decreased by the elimination of toxic substances, the bundle is released and opens-up the protein shell (capsid) enclosing its genetic material and the membrane, allowing viral DNA to escape into the nucleus for replication."It turns out the incorporation of a PLA2 enzymatic domain is only one strategy, even as far as the family of parvoviruses is concerned. Here, we show yet a new strategy that may not be limited to one parvovirus lineage, but to other economically very important parvoviruses, such as parvoviruses of domestic fowl and farmed mink," says Judit Pénzes, a former postdoctoral fellow at INRS and first author of the paper published on August 18, 2020.INRS Professor Emeritus Peter Tijssen, lead author of the publication, raises another interesting point: the host-driven convergent evolution of this method of entry into the cell. "Two parvoviruses with different DNA sequences, which both targeting shrimps, have adopted similar strategies for reaching the nucleus," he says.Using a microscope nearly two floors high, the FEI Titan Krios, Judit Pénzes was able to solve the complete structure of the virus on a near-atomic scale. "You could already feel the energy rumbling through the enormous machine upon entering the facility. I think that it's probably the same to what scientists involved in space exploration must have felt when they saw a rocket ready to lift off for the first time," says the postdoctoral student.Eventually, the discovery of this mechanism could lead to a better understanding of how viruses enter cells and even to a cure. "If we know how the parvovirus manages to release its DNA into the nucleus of the host cell, we can try to find a molecule to block this action," concludes Professor Tijssen. The collaboration with the Florida-based research team will allow them to deepen the knowledge on this subject and possibly find other methods of entry that are yet unknown.
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Zoology
| 2,020 |
September 23, 2020
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https://www.sciencedaily.com/releases/2020/09/200923164617.htm
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PFAS in seabirds: Narragansett Bay, Massachusetts Bay, Cape Fear
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Evidence continues to accumulate about human and wildlife exposure to chemical compounds called per- and polyfluoroalkyl substances, collectively referred to as PFAS, and their deleterious effects on the environment. The latest study, by a University of Rhode Island graduate student, found high levels of the compounds in seabirds from offshore Massachusetts and coastal Rhode Island and North Carolina.
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Chief among the findings was the discovery that one type of PFAS, perfluorooctanesulfonic acid or PFOS, which has not been produced since the early 2000s, is the most dominant PFAS compound in the birds from all three sites, further illustrating how these chemicals do not breakdown in the environment and can remain in animal tissues for many years."Wildlife is being inundated with PFAS," said Anna Robuck, a doctoral student at the URI Graduate School of Oceanography, who has been studying PFAS with Professor Rainer Lohmann since 2016. "We don't really understand what that means for wildlife health overall, since scientists are just catching up with what PFAS means for human health. What we do know is that we're seeing significant concentrations that laboratory studies tell us are concerning."Her research was published this month in the journal The concentrations of PFAS Robuck found in seabird livers are comparable to levels found in other bird studies that suggested that the compounds may be causing negative reproductive health outcomes."This speaks to the incredible persistence of these compounds," she said. "Once in the environment, it's there in perpetuity for it to be accumulated by wildlife. And even though we no longer produce PFOS, we still produce a series of related compounds that, once in the environment, readily transform into PFOS."Robuck, a native of Chadds Ford, Pennsylvania, measured the levels of PFAS in the livers of herring gulls from Narragansett Bay, Rhode Island, great shearwaters in the offshore waters of Massachusetts Bay, and royal and sandwich terns from Cape Fear, North Carolina. All of the birds were juveniles found dead near their breeding or feeding grounds. The three sites were chosen to represent birds from an urban area where PFAS exposure is common (Narragansett Bay), an offshore area of birds that seldom approach land (Massachusetts Bay), and an area downstream of a major PFAS producer (Cape Fear)."We studied their livers because there is a specific protein in the liver that PFAS love to bind to," Robuck said. "We also know that in humans, PFAS exposure leads to liver damage and impairment of function."Among her other findings, Robuck discovered that the North Carolina birds that hatched downstream from a PFAS production site contained several novel PFAS compounds that have been created in recent years to replace those that have been phased out."The nesting colonies where we got the Cape Fear birds from are 90 miles from the production facility," she said. "This is the first detection of these compounds in liver tissue and the furthest distance from the known industrial source."Surprisingly, we also found those same novel PFAS in birds that have no connection to Cape Fear -- in one gull from Narragansett Bay and two shearwaters in Massachusetts Bay," she added. "It suggests that these replacement compounds are highly persistent and capable of migrating further in the environment than we were aware of. There also may be more sources of the compounds than we know about."Of particular note, Robuck also found that as PFAS levels increased in the birds, the phospholipid levels in their liver decreased, a finding that is especially concerning."That's a really big deal because fats are important for reproductive health, migration, raising their young successfully, and other elements of their life cycle," Robuck said. "The fact that there is an observable relationship between PFAS and fats deserves a lot more investigation to see what it could be doing to wildlife populations."In addition, Robuck detected the same PFAS levels in the offshore birds as those from inshore Rhode Island."They didn't have the same kind of PFAS, but they had the same total level," she said. "I expected offshore birds to be a lot lower, since those birds never come to land. It suggests that even our most remote and most pristine habitats are facing exposure to these compounds."Robuck's next study will analyze the PFAS concentrations in other tissues from the same birds. She hopes the resulting data will be included in future government assessments of the impact of PFAS in wildlife and the environment.
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Zoology
| 2,020 |
September 22, 2020
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https://www.sciencedaily.com/releases/2020/09/200922172628.htm
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Silk offers homemade solution for COVID-19 prevention
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With personal protective equipment still in short supply, researchers at the University of Cincinnati examined what common household fabrics might work best as a face covering.
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Next to a single-use N95 respirator or surgical mask, UC found the best alternative could be made by a hungry little caterpillar. Silk face masks are comfortable, breathable and repel moisture, which is a desirable trait in fighting an airborne virus.Perhaps best of all, silk contains natural antimicrobial, antibacterial and antiviral properties that could help ward off the virus, said Patrick Guerra, assistant professor of biology in UC's College of Arts and Sciences.Studies have shown that copper, in particular, can kill bacteria and viruses on contact. And that's where the little caterpillars have their own superpower, Guerra said."Copper is the big craze now. Silk has copper in it. Domesticated silk moths eat mulberry leaves. They incorporate copper from their diet into the silk," Guerra said.Many health care providers wear a surgical mask in combination with an N95 respirator. The outer covering helps prolong the life of the N95 respirator by keeping it clean. Guerra, whose wife, Evelyn, is a medical doctor, said silk might be an especially good choice for this outer cover as they perform similarly to surgical masks that are in short supply."Cotton traps moisture like a sponge. But silk is breathable. It's thinner than cotton and dries really fast," Guerra said.With COVID-19 surging in parts of the United States, face masks have become a focal point of prevention.In the UC biology lab, researchers tested cotton and polyester fabric along with multiple types of silk to see how effective a barrier each is for repelling water, representing respiratory droplets containing the virus. They found that silk worked far better as a moisture barrier than either polyester or cotton, both of which absorb water droplets quickly.UC's study concluded that silk performs similarly to surgical masks when used in conjunction with respirators but has the added advantages of being washable and repelling water, which would translate to helping to keep a person safer from the airborne virus."The ongoing hypothesis is that coronavirus is transmitted through respiratory droplets," Guerra said. "If you wore layers of silk, it would prevent the droplets from penetrating and from being absorbed. Recent work by other researchers also found that increasing layers of silk improves filtration efficiency. This means that silk material can repel and filter droplets. And this function improves with the number of layers."The study was published this month in the journal "We're trying to address this critical problem. Health care workers still don't have enough personal protective equipment, namely N95 respirators or basic surgical masks," Guerra said.Previously, Guerra studied the neurobiology behind the incredible multigenerational migration of monarch butterflies across North America. Now UC students raise silk moths (UC postdoctoral researcher Adam Parlin wrote an undergraduate instruction manual for care and feeding of the moths he titled, "How to Train Your Bombyx," a riff on the DreamWorks' animated dragon movies. The cover features a picture of the adult moth. With its big head, enormous eyes and fanned wings, the silk moth indeed resembles a night fury from the films."These little guys are entertaining," he said.As part of his research, Parlin studied how the caterpillars make their protective silk cocoons. When they reach a point in their life cycle, the caterpillars become manic workaholics. For 72 straight hours they spin and spin their silk to create a luxurious, breathable fortress where they can pupate safely into a fuzzy white moth.Researchers created cardboard arenas with a wooden dowel in the center upon which the caterpillars can spin their silk cocoons. The caterpillars work methodically and nonstop, initially spinning silk from the top of the dowel at an angle to the cardboard like a tent. Once the tent is finished, they work in earnest on building their grape-sized cocoon in a corner of it."If the cocoon gets damaged, they just build a second layer around it," Parlin said.The moisture-trapping cocoon provides an ideal microclimate to keep the caterpillars happy despite any sudden changes in the weather."The silk cocoons prevent moisture from getting in and keeps the animal from desiccation or drying out," Guerra said.Now Guerra is investigating how long the virus survives on silk and other materials.As shortages of personal protective equipment continue to plague health care providers, Guerra said homemade masks will continue to play an important role in keeping people safe from COVID-19."Silk has been with us for a while -- since the days of the Silk Road," Guerra said. "It's not a new fabric, yet now we're finding all these new uses for it."
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Zoology
| 2,020 |
September 22, 2020
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https://www.sciencedaily.com/releases/2020/09/200922112310.htm
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Better conservation planning can improve human life too
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Conservation planning can be greatly improved to benefit human communities, while still protecting biodiversity, according to University of Queensland research.
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PhD candidate Jaramar Villarreal-Rosas, from UQ's School of Earth and Environmental Sciences, said the benefits people receive from ecosystems -- known as ecosystem services -- are under increasing threat globally due to the negative impacts of human activities."There's been a substantial decrease in the quality and quantity of freshwater from wetland ecosystems in the Americas since European settlement, according to the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services," Ms Villarreal-Rosas said."The same data shows that, at the same time, pollination services -- from insects and birds -- are declining in Europe and Central Asia."These are critical services we sometimes don't even think about -- the food we eat, the air we breathe, or the sense of relaxation after a walk in a park."And to date, landscape planning decisions have largely been made without fully considering the multiple benefits people obtain from nature."The researchers analysed 326 scientific papers that applied systematic conservation planning for ecosystem services worldwide, classifying them based on the extent to which they correctly integrated the benefits people receive from ecosystems, and whether multiple values and connections to land were considered.They revealed that only two per cent of conservation plans globally considered all ecosystem services components that determine benefit people, acknowledging different values of the land."This means we're largely making planning decisions that may put ecosystem services at risk, and in turn, people's livelihoods and lifestyles may be greatly affected," Ms Villarreal-Rosas said."Conservation plans are falling short of maximising benefits for both people and nature."There is an urgent need to develop efficient and effective planning strategies to protect and restore ecosystem services for multiple stakeholders."Senior author Professor Jonathan Rhodes said the research team did just that -- outlining a formal process that governments and policy makers can use when putting together their conservation plans."Solutions must explicitly include benefits to different people in space, time and socioeconomic status," Professor Rhodes said."People have different values and connections to land and these should be acknowledged to ensure planning decisions have positive outcomes for multiple people."Through the principles we've outlined in this study, we're hoping to not only improve ecosystem services globally, but to increase efficiency, transparency and equity in decision making processes."We see conservation planning shifting towards holistic approaches, where both the diversity of people and nature is valued, respected, and protected."Making these changes is essential to achieve international policy agendas such as the United Nations Sustainable Development Goals."
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Zoology
| 2,020 |
September 21, 2020
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https://www.sciencedaily.com/releases/2020/09/200921111709.htm
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Dino teeth research prove giant predatory dinosaur lived in water
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A discovery of more than a thousand dinosaur teeth, by a team of researchers from the University of Portsmouth, proves beyond reasonable doubt that Spinosaurus, the giant predator made famous by the movie Jurassic Park III as well as the BBC documentary Planet Dinosaur was an enormous river-monster.
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Research published today in the journal Until recently it was believed that dinosaurs lived exclusively on land. However, research published earlier this year showed that Spinosaurus was well adapted to an aquatic lifestyle, due to its newly discovered tail. This latest research of 1,200 teeth found in the same region further supports this theory.Scientists from the University of Portsmouth collected the fossilised remains from the site of an ancient river bed in Morocco. After analysing all of them it was discovered there was an abundance of Spinosaurus teeth, which are distinct and easily identifiable.David Martill, Professor of Palaeobiology at the University of Portsmouth, said:"The huge number of teeth we collected in the prehistoric river bed reveals that Spinosaurus was there in huge numbers, accounting for 45 per cent of the total dental remains. We know of no other location where such a mass of dinosaur teeth have been found in bone-bearing rock."The enhanced abundance of Spinosaurus teeth, relative to other dinosaurs, is a reflection of their aquatic lifestyle. An animal living much of its life in water is much more likely to contribute teeth to the river deposit than those dinosaurs that perhaps only visited the river for drinking and feeding along its banks."From this research we are able to confirm this location as the place where this gigantic dinosaur not only lived but also died. The results are fully consistent with the idea of a truly water-dwelling, "river monster." "Professor Martill worked alongside two students studying for their Masters Degree in Paleontology at the University of Portsmouth.Thomas Beevor said: "The Kem Kem river beds are an amazing source of Spinosaurus remains. They also preserve the remains of many other Cretaceous creatures including sawfish, coelacanths, crocodiles, flying reptiles and other land-living dinosaurs. With such an abundance of Spinosaurus teeth, it is highly likely that this animal was living mostly within the river rather than along its banks."Aaron Quigley, explained the process of sorting through the teeth: "After preparing all the fossils, we then assessed each one in turn. The teeth of Spinosaurus have a distinct surface. They have a smooth round cross section which glints when held up to the light. We sorted all 1200 teeth into species and then literally counted them all up. Forty-five per cent of our total find were Spinosaurus teeth."
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Zoology
| 2,020 |
September 21, 2020
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https://www.sciencedaily.com/releases/2020/09/200921102538.htm
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Bird beak revealed by laser imaging informs early beak function and development
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Confuciusornis was a crow-like fossil bird that lived in the Cretaceous ~120 million years ago. It was one of the first birds to evolve a beak. Early beak evolution remains understudied. Using an imaging technique called Laser-Stimulated Fluorescence, researchers at the University of Hong Kong (HKU) address this by revealing just how different the beak and jaw of Confuciusornis were compared to birds we see today.
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Laser-Stimulated Fluorescence (LSF) is an imaging technique co-developed at HKU that involves shining a laser onto a target. It is well-known in palaeontology for making fossil bones and the soft tissues preserved alongside them glow-in-the-dark. LSF has revealed fine skin details and other previously-invisible soft tissue in a wide range of fossils, especially those of early birds and other feathered dinosaurs.HKU PhD student Case Vincent Miller and his supervisor Research Assistant Professor Dr. Michael Pittman (Vertebrate Palaeontology Laboratory, Division of Earth and Planetary Science & Department of Earth Sciences) led this study with Thomas G. Kaye of the Foundation for Scientific Advancement (Arizona, USA) and colleagues at the Shandong Tianyu Museum of Nature (Pingyi, China). Under LSF, which was co-developed by Dr. Pittman and Mr. Kaye, the team revealed the fingernail-like 'soft beak' of Confuciusornis, a feature that covers the beak of every bird and is called the rhamphotheca. The example the team found in Confuciusornis was preserved detached from the bony part of the beak. "Fossilised rhamphothecae have been reported in fossil birds before," said Dr. Pittman, "but no one has really asked what they tell us about the earliest beaked birds."The international research team reconstructed what the beak looked like in life, and used this to consolidate knowledge of the beak of Confucusornis across all known specimens. In highlighting that the rhamphotheca was easily-detachable and by performing the first test of jaw strength in a dinosaur-era bird, the team suggested that this early beaked bird was suited to eating soft foods. Finally, the team highlight differences in how the beak is assembled to show that despite looking like living birds, the early beaks of Confuciusornis and its close relatives are fundamentally different structures to those seen in modern birds.Regarding future plans, Mr. Miller said, "Our research has raised a lot of interesting questions going forward. We know so little about fossil rhamphothecae and plan on using LSF to study even more fossils to find more of these hidden gems. I am particularly interested in seeing whether beak attachment strength in living birds has any correlation with the overall strength of their jaw. This might help us to better understand fossil birds. This study is only the first glimpse into this interesting and new line of study into early beaks, so I am very excited."
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Zoology
| 2,020 |
September 18, 2020
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https://www.sciencedaily.com/releases/2020/09/200918104244.htm
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How researchers look at the bird brain in action
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How do birds make decisions and which brain regions are particularly active when they solve tasks? Researchers from the Department of Biopsychology at Ruhr-Universität Bochum (RUB) are investigating these questions. So far, only anesthetized birds and therefore passive experiments could be examined using the functional magnetic resonance imaging (fMRI). Thus, the examination of brain processes during active tasks was not possible. Now the cognitive neuroscientists at the Biopsychology lab have constructed an experimental set-up which allows them to carry out fMRI examinations on awake pigeons and thus also investigate cognitive processes for the first time. They published their results online in the journal "
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Within the new experimental setup, the animals can be presented with tasks that they actively work on. During this time, fMRI recordings are continuously made so that the activity of the brain areas that are active during task processing is recorded. In contrast to fMRI examinations in humans, in which the participants can respond to tasks by pressing buttons, the pigeons respond by opening and closing their beak, which is registered by a sensor below the beak.The researchers checked the quality of the gained fMRI images in a test study. The pigeons had to learn to differentiate between two colours. The animals learned to react to the appearance of the correct colour by opening their beak and received a reward for correct answers. "This study was just a test run to show whether the scan in awake behaving birds works as we had expected," explains Mehdi Behroozi, the first author of the study."The fMRI data of the test study showed that even with this simple discrimination task, a whole network of areas in the pigeon's brain is active, which could not yet be represented in its entirety," says Onur Güntürkün, Professor of Biopsychology at RUB about the results of the test study. "Now the way is open for investigations with more complex cognitive tasks. Especially at a time when we are amazed to find out more and more how intelligent birds are, this breakthrough will help to identify the brain basis of these abilities," adds Güntürkün.In functional magnetic resonance tomography, slice images of the brain are generated using a strong magnet. They show how well individual parts of the brain are supplied with oxygen. Brain areas that are very active have a lower oxygen saturation than less active areas. Therefore one can for instance see which areas of the brain are particularly challenged when solving a task.
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Zoology
| 2,020 |
September 16, 2020
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https://www.sciencedaily.com/releases/2020/09/200916131041.htm
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Scientists identify gene family key to unlocking vertebrate evolution
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New University of Colorado Boulder-led research finds that the traits that make vertebrates distinct from invertebrates were made possible by the emergence of a new set of genes 500 million years ago, documenting an important episode in evolution where new genes played a significant role in the evolution of novel traits in vertebrates.
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The findings, published today in "Every animal essentially has the same basic core set of Lego pieces to make them. What this paper shows is that vertebrates have a few special pieces in addition to that, and we identify those special pieces," said Daniel Medeiros, senior author of the paper and associate professor of ecology and evolutionary biology.These special pieces in vertebrates are known as the Endothelin signaling pathway, a set of genes that influence how cells talk to each other. The researchers found this gene family is responsible for allowing neural crest cells -- cells that develop into unique vertebrate traits like skeletal parts, pigment cells and our peripheral nervous system -- to proliferate and specialize into different roles throughout the body.Evolutionary theories have given weight to the role of genome duplication in the evolution of new traits, and for good reason. When a genome duplicates, new copies of existing genes can take on new roles in an organism. But since previous ideas were based mostly on observation, Medeiros wanted to test if gene duplication could have allowed vertebrates to become so special, or if the appearance of brand new genes could have played a role.Medeiros and his colleagues tested the hypothesis that new gene families could also give rise to new traits by genetically modifying the larvae of sea lamprey, a type of jawless fish, through identifying and removing this specific gene family. If their prediction was correct, removing it would revert a sea lamprey during its larval development into a more invertebrate-like worm, a close evolutionary ancestor."And we found that by knocking out this new gene family, you can almost erase most of the key vertebrate traits that make vertebrates special," said Medeiros.While gene duplication is still an important part of the evolutionary process -- as this new gene family is also duplicated in vertebrates -- they found that duplication was not as critical in giving rise to the special neural crest cell types that vertebrates evolved as was the emergence of this new gene family.This finding is significant in part because it's rare to find clear roles for genes that are unique to vertebrates, said lead author Tyler Square, who recently completed his PhD in the Medeiros lab and is now at the University of California Berkeley."We thought that gene duplication was the most important thing. But here, we found both of those things [new genes and duplications] happening at once," said Square.Fish were the first vertebrates, from which all others evolved -- including humans. But there is a gap in the fossil record right when the first fish were evolving, because they had little, soft skeletons which were not preserved in the fossil record.So how can scientists work out where the first fish came from, and therefore how all vertebrates came to be?"Rather than looking at fossils, we use tools like molecular biology and genetics to try to understand how evolution has happened, kind of like genetic paleontology," said Medeiros. "In the deepest molecular genetic terms, we're trying to reverse engineer how a creature evolves. It's the closest you can get to Jurassic Park."The creature they chose to reverse engineer, however, might seem a bit monstrous."While most people think of a big ugly hurricane of teeth sticking on to fish and chewing on them, sea lamprey are surprisingly cute when they're little baby larvae," said Square.The sea lamprey, a jawless fish, diverged in evolution from other fish 500 million years ago. Because they hold onto several older vertebrate features, this gives the researchers the best snapshot of the early stage of vertebrate evolution with a living organism today."A lamprey and a human are extremely different. But by doing these kinds of studies, we can know what makes them the same," said Square. "This is stuff that's really fundamental, not just to mammals and humans, but to every vertebrate that exists."Square and his colleagues used the gene-editing tool CRISPR during its early days to find out how important this new gene family is to making vertebrates, well, vertebrates."It was the wild west of CRISPR days," said Square. "But we couldn't have done this whatsoever if it weren't for CRISPR."Not only did this technology allow the researchers to test hypotheses functionally, by knocking out genes, but they were also the first team to use CRISPR in sea lampreys. Previously, this technology had only been used in some vertebrates like mice, frogs and zebrafish."And that's a really narrow view of life on the planet," said Medeiros. "What CRISPR has done is democratized genetic studies across diverse organisms. It's super powerful for answering evolutionary questions."
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Zoology
| 2,020 |
September 15, 2020
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https://www.sciencedaily.com/releases/2020/09/200915194252.htm
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Extremely social robotic fish helps unravel collective patterns of animal groups
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The spectacular and complex visual patterns created by animal groups moving together have fascinated humans since the beginning of time. Think of the highly synchronized movements of a flock of starlings, or the circular motion of a school of barracudas. Using state-of-the-art robotics, a research team from the University of Konstanz, Science of Intelligence, and the Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB) shows that animals' speed is fundamental for collective behavioral patterns, and that ultimately it is the faster individuals that have the strongest influence on group-level behavior. The study, published in
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Researchers have long focused on identifying the emergence of collective patterns. Thanks to a combination of behavioral experiments, computer simulations, and field observations, it is clear that many seemingly complex patterns can actually be explained by relatively simple rules: move away from others if they get too near, speed up towards others if they get too far away, and otherwise move at the same speed and align with your group mates."Besides understanding the rules that individuals follow when interacting with others, we need to consider the behaviors and characteristics of those individuals that make up the group and determine their influence for collective outcomes"says Dr. Jolle Jolles, scientist at the Zukunftskolleg, University of Konstanz, and lead author of the study. "Across the animal kingdom, it has been found again and again that animals tend to differ considerably from one another in their behavior such as in terms of their activity, risk-taking, and social behavior." What are the consequences of this behavioral heterogeneity when it comes to collective behavior? And how can one test for its social consequences?To disentangle the role of individual differences in collective behavior and the mechanisms underlying this type of behavior, the research team built "Robofish," a robotic fish that not only realistically looks and behaves like a guppy -- a small tropical freshwater fish -- , but also interacts with the live fish in a natural way. The experimenters paired the robotic fish with a guppy and programmed it to always follow its partner and copy its movements, lacking however any movement preferences of its own. The team then used high-definition video tracking and a closed-loop feedback system to let the robotic fish respond to the live fish's actions in real-time."One of Robofish's simple interaction rules was to keep a constant distance to its shoal mate" explains Dr. David Bierbach, who works within the Berlin-based Excellence Cluster 'Science of Intelligence' at the HU Berlin and the IGB, and is senior author on the paper. "Using this rule, our Robofish tried to keep the same distance to the live fish by accelerating and decelerating whenever the live fish did. Also, programming the robotic fish without any own movement preferences gave us the unique opportunity to investigate how individual differences in the behavior of the live fish led to group-level differences. In short, with our unique approach, we could isolate the effect of the fish's movement speed on the pair's collective behavior."The researchers first quantified the guppies' natural movement speed by observing their movements when alone in an open environment, and found that there were large individual differences in how fast guppies tended to move. When the fish were subsequently tested with Robofish, the fish and Robofish tended to swim naturally together as a pair. However, the researchers observed that there were large differences in the social behaviors between the pairs: pairs in which the guppy had a faster movement speed tended to be much more aligned, more coordinated, and less cohesive, and the guppy emerged as a clearer leader. As Robofish behaved according to the same identical rules with each and every guppy, it is the individual speed of the guppies that must have led to these differences in group-level properties.By involving state-of-the-art robotics, this research shows that individual speed is a fundamental factor in the emergence of collective behavioral patterns. As individual differences in speed are associated with a broad range of phenotypic traits among grouping animals, such as their size, age, and hunger level, the results of this study may help understand the role of such heterogeneity in animal groups.Future studies using the interactive Robofish will focus on other aspects of collective behavior: For example, how can animals act in synchrony if they just respond to the actions of their neighbors? "We want to improve Robofish's software so that it can predict and anticipate the live fish's next steps, which is assumed to be how animals do it." says David Bierbach.Understanding these mechanisms is not only fundamentally important as it reveals information about the mechanisms that underlie collective behavior and decisions, but also because this knowledge can be applied to artificial systems and used to develop machines that move collectively, such as robot swarms, driverless cars, and drones.
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Zoology
| 2,020 |
September 15, 2020
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https://www.sciencedaily.com/releases/2020/09/200915155821.htm
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Fish oil without the fishy smell or taste
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A new study, co-led by University of Cincinnati researchers, describes the development of a refining process that scientists deem a superior method to help produce better dietary omega-3 health and dietary supplements containing fish oil.
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Fish oil is widely known to be an excellent dietary source of omega-3 polyunsaturated fatty acids (PUFAs) having positive effects on human health including heart and eye health, inflammation and bone density.The novel process uses a new tool called a vortex fluidic device (VFD) developed by research collaborators at Flinders University of Australia. The process is successful in lifting the quality of active ingredients of the PUFAs in fish oil, says Harshita Kumari, the study's co-author and associate professor of pharmaceutical sciences at UC's James L. Winkle College of Pharmacy.The study now appears in Nature Papers Journals Researchers applied the VFD-mediated encapsulated fish oil to enrich the omega-3 fatty acid content of apple juice."This novel process enriches the omega-3 fatty acid content of apple juice remarkably without changing its taste," says Kumari, adding that two common consumer complaints regarding fish oil supplements is the taste and odor. Liquid omega-3 oils can also break down over time when exposed to oxygen which leads to degradation.Compared to regular homogenization processing, Kumari says the device can raise PUFA levels and purity by lowering oxidation and dramatically improving shelf life. Natural bioactive molecules, also used in processing, reveal that the fish oil medium can absorb flavonoids and other health supplements.
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Zoology
| 2,020 |
September 15, 2020
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https://www.sciencedaily.com/releases/2020/09/200915105949.htm
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Rare pattern observed in migrating common swifts
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"Our study is very significant for understanding how organisms, in this case the common swift, can migrate from one part of the world to another, where access to food is much better at a given time," says Susanne Åkesson, professor at Lund University and principal investigator of the study.
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Common swifts that nest in Sweden and northern Europe arrive in sub-Saharan Africa four to six weeks later than the swifts that nest in southern Europe. By that time, the southern European swifts have already migrated even further south on the African continent. Hence the term chain migration, as opposed to the much more common pattern known as leap-frog migration, in which the populations that arrive first in a location claim the territory and occupy it, forcing populations that arrive later to leap-frog over the occupied area and fly further.The common swift is the most mobile terrestrial bird in the world. When it is not breeding, it spends 24 hours a day airborne, for a total of ten months a year. According to the researchers, this has contributed to the species developing its unique migration pattern. Life in the air means that the swifts need a steady supply of energy and therefore food in the form of insects. This explains why the southern European populations migrate even further south in Africa when food availability increases there in the second half of the wintering period. It also explains why they are larger than their relatives from northern Europe. Quite simply, they make sure always to be in the region with the greatest availability of insects.The researchers identified another factor determining the development of the common swift's chain migration: they cannot claim a territory in the same way as birds that spend more time on the ground."The core reason why the common swift engages in chain migration, whereas almost all other birds such as songbirds, ducks, geese and waders have leap-frog migration patterns, can probably be found in the amount of time they spend airborne. The common swift is unique in spending ten months in the air," says Susanne Åkesson."I think it is amazing that they know where food is to be found and when they should head for that specific location. They migrate over continents in such a way as to ensure continuous access to food and thereby to survive -- they have a lifespan of over 20 years," she continues.The researchers tracked 102 common swifts (Chain migration has previously only been observed in two species: the sharp-shinned hawk and the northern gannet.
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Zoology
| 2,020 |
September 14, 2020
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https://www.sciencedaily.com/releases/2020/09/200914083841.htm
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How civil wars affect wildlife populations
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A new study comprehensively reveals how civil wars impact wildlife in countries affected by conflict.
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Researchers at the University of East Anglia (UEA), in the UK, Federal University of Paraíba (UFPB), Brazil, and University of Agostinho Neto (UAN), Angola, found that the main impacts of civil wars on native mammals are often indirect, ultimately arising from institutional and socio-economic changes, rather than from direct military tactics.Increased access to automatic weapons and suspension of anti-poaching patrols were leading causes of wildlife population collapse, while installation of military bases within core conservation areas, overhunting of large-bodied mammals, and new settlements of displaced refugees also strongly impacted species.Published today in the journal The authors warn that even during post-war peace times, wild mammal populations will fail to recover as long as rural people living in war-torn countries remain armed and wildlife management regulations cannot be enforced. They call for robust international policies that can prevent the consequences of warfare, warning that restoring depleted wildlife populations may take many decades and require active intervention efforts.Civil wars often coincide with global biodiversity hotspots, however little is known about how they affect wildlife. This study drew local ecological knowledge to assess for the first time the main consequences of a prolonged civil war in Southwest Africa on forest and savannah mammals, using Angola as a case study. The country is home to at least 275 species of mammals, many of them historically hunted by the local communities before, during and after the intermittent 27-year Angolan civil war (1975-2002).In Angola's main protected area, Quiçama National Park and Quiçama Game Reserve, the abundance of 20 out of 26 wild mammal species studied was 77 per cent lower after the war compared to the pre-war baseline, particularly for large-bodied species such as elephants in open-savannah environments. Significantly, this decline was not reversed by the end of the post-war period (2002-2017).Franciany Braga-Pereira, a Zoology PhD candidate at UFPB, led the study. Ms Braga-Pereira said: "Currently, 36 countries worldwide are experiencing civil wars and most of these conflicts are either fuelled or funded by international interests or began after an external intervention."These internationalized conflicts are more prolonged and less likely to find a political resolution. Therefore, considering measures that can reduce the impact of warfare on wildlife, we emphasize the intentional or inadvertent complicity of foreign powers, which should promote policies that mitigate the detrimental environmental impacts of armed conflicts."Co-author Prof Carlos Peres, from UEA's School of Environmental Sciences, said: "Low-governance developing countries are struggling as it is, even during peacetimes, to protect their wildlife resources, never mind the colossal adverse consequences of breakdown in law-and-order brought about by a civil war. Yet there are no adequate international mechanisms to deploy peace forces to maintain the status quo of vulnerable wildlife populations in troubled parts of the world."The research involved interviews with expert local hunters, which revealed that large-bodied mammals, such as red buffalo, kudu and red sable, were preferred targets that had been overhunted during the war. As their populations became increasingly depleted, the size structure of prey species gradually shifted towards smaller-bodied species, for example bushpig, bushbuck kewel and blue duilker, during the post-war period. However, once the depletion in forest was lower than in the savannah, hunters operating in forest areas were occasionally able to kill larger species in the post-war period.In their model of how civil wars impact wildlife, the authors explain that civil war could be a double-edged sword, resulting also in declines in extractive industries such as oil, mining and agribusiness, which can benefit wildlife, and demilitarized and landmine zones, which severely discourage human settlements and game hunters, thereby creating potential game refuges as passive 'no-take' areas.
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Zoology
| 2,020 |
September 11, 2020
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https://www.sciencedaily.com/releases/2020/09/200911200006.htm
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Trout don't follow the weather forecast
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An endangered fish in California might use its internal clock to decide when to migrate, according to a study by the University of Cincinnati.
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UC visiting assistant professor of biology Michael Booth studied the migration patterns of steelhead, a subpopulation of rainbow trout that migrates to the Pacific Ocean, where the growing fish hunt and feed until they return to their natal freshwater streams to spawn.While working at the United Water Conservation District, Booth used 19 years of records from a designated fish trap on southern California's Santa Clara River to identify potential environmental drivers that spur some fish to make the arduous trip to the Pacific Ocean. The trap is part of a diversion off the river where fish can be counted and, if necessary, relocated downstream past the river's low or dry spots.He found that steelhead migration was triggered by the lengthening daylight of spring rather than factors like recent rains, which had little correlation to migration.The study was published in the The Santa Clara River is one of the largest coastal watersheds in southern California. It's an important source of water for Ventura County's $2 billion agriculture industry, famed for its strawberries, lemons, peppers and avocados.But sections of the river often go dry completely, isolating fish in upstream tributaries until the seasonal rains return."The Santa Clara River is a massive desert river," Booth said. "The river channel is braided with sand and gravel. It's about 1,000 feet wide in its lower sections and it's always changing."The river is fed by cold-water mountain streams typically associated with rainbow trout. Some of the fish remain in these tributaries their entire lives, spawning and dying not far from where they hatched. Others undergo physiological changes that allow them to tolerate the saltwater of the Pacific Ocean. While rainbow trout are typically green and pink, steelhead can take on a silvery sheen, giving them their name.Steelhead in southern California are federally protected as an endangered species. Anglers must release any they catch.Booth said there are big genetic benefits to making the dangerous trip to the Pacific Ocean. Steelhead grow much faster in the food-rich ocean than trout that remain in the freshwater streams. Fish that migrate to the ocean have an advantage in passing on their genes to subsequent generations when they return to spawn, he said."A 3-year-old resident trout might be a foot long, but a steelhead might be 3 feet long," he said. "Their fecundity is directly related to size. So the bigger the fish, the more eggs it can make. There's a really strong genetic advantage to making more babies."The study recommended limiting the extraction of water from the Santa Clara River during the migration months of mid-March to May. Likewise, Booth said the water flow in the river should be maintained where possible to allow late migrating steelhead to return upstream.The trout's migration opportunities might shrink from climate change, the study warned."There are a lot of challenges in the Santa Clara River. The water levels go up and down," he said. "This river has a massive sediment load. During a big storm, the river bed can erode 20 feet. The water looks like a smoothie coming downstream."Booth said steelheads likely wait for sediment-choked river water to settle before migrating.Since the river in most years is only navigable after storms get water flowing again, Booth hypothesized that heavy rains triggered the steelhead's movement to the ocean."We thought the fish would migrate when the river was flowing and wouldn't migrate in years without storm events," Booth said. "It turned out that wasn't the case. They migrated regardless of whether the river was flowing to the ocean."Booth isn't sure if the fish that reach dry spots head back upstream or simply perish in the main stem of the river.The study is significant because it could help wildlife managers and government regulators make more informed decisions about water use. The Santa Clara River is a major source of water for agriculture and people who live in the watershed. Knowing what months are crucial for steelhead migration could help wildlife managers avoid conflicts."It's really hard for a water manager to decide this is when we can and can't divert water if you have no data on when the fish are migrating," Booth said.For fish that miss the narrow window to navigate the Santa Clara while it's running, there are few practical solutions, Booth said."This is a very wicked problem. The water available is dependent on rain, snowfall and the recharge of the groundwater," he said. "We can avoid taking water from the river or reducing extractions but there isn't an extra water source to make the river flow during droughts."But Booth is optimistic the steelhead will persist in the Santa Clara River, at least for now."Steelhead are very resilient. They've been holding on for a while," he said
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Zoology
| 2,020 |
September 10, 2020
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https://www.sciencedaily.com/releases/2020/09/200910150326.htm
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Odors produced by soil microbes attract red fire ants to safer nest sites
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Newly mated queens of the red fire ant select nest sites with a relatively low pathogen risk by detecting odors produced by soil bacteria that inhibit the growth of ant-infecting fungi, according to a study published September 10 in the open-access journal
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Soil-dwelling insects are at risk of pathogen infection. When choosing nesting sites, insects could reduce this risk by avoiding contact with pathogens. Yet it has not been clear whether social insects can reliably detect and avoid pathogens at potential nesting sites. In the new study, the researchers show that newly mated queens of a soil-dwelling ant -- the red fire ant The ants are attracted to two volatile compounds produced by these bacteria. Queens in the actinobacteria-rich, pathogen-depleted soil benefit from a higher survival rate, enabling the ant population to grow. According to the authors, the results show for the first time that ants may be attracted to soil based on chemical cues produced by resident actinobacteria, which may provide protection against pathogenic fungi. The findings may help guide strategies that alter the soil microbiota to manage The authors note, "Queens of the red fire ant apply an interesting way to avoid potential pathogens infection when nesting."
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Zoology
| 2,020 |
September 9, 2020
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https://www.sciencedaily.com/releases/2020/09/200909154520.htm
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Velcro-like food sensor detects spoilage and contamination
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MIT engineers have designed a Velcro-like food sensor, made from an array of silk microneedles, that pierces through plastic packaging to sample food for signs of spoilage and bacterial contamination.
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The sensor's microneedles are molded from a solution of edible proteins found in silk cocoons, and are designed to draw fluid into the back of the sensor, which is printed with two types of specialized ink. One of these "bioinks" changes color when in contact with fluid of a certain pH range, indicating that the food has spoiled; the other turns color when it senses contaminating bacteria such as pathogenic The researchers attached the sensor to a fillet of raw fish that they had injected with a solution contaminated with The results, published today in the journal Such smart food sensors might help head off outbreaks such as the recent salmonella contamination in onions and peaches. They could also prevent consumers from throwing out food that may be past a printed expiration date, but is in fact still consumable."There is a lot of food that's wasted due to lack of proper labeling, and we're throwing food away without even knowing if it's spoiled or not," says Benedetto Marelli, the Paul M. Cook Career Development Assistant Professor in MIT's Department of Civil and Environmental Engineering. "People also waste a lot of food after outbreaks, because they're not sure if the food is actually contaminated or not. A technology like this would give confidence to the end user to not waste food."Marelli's co-authors on the paper are Doyoon Kim, Yunteng Cao, Dhanushkodi Mariappan, Michael S. Bono Jr., and A. John Hart.The new food sensor is the product of a collaboration between Marelli, whose lab harnesses the properties of silk to develop new technologies, and Hart, whose group develops new manufacturing processes.Hart recently developed a high-resolution floxography technique, realizing microscopic patterns that can enable low-cost printed electronics and sensors. Meanwhile, Marelli had developed a silk-based microneedle stamp that penetrates and delivers nutrients to plants. In conversation, the researchers wondered whether their technologies could be paired to produce a printed food sensor that monitors food safety."Assessing the health of food by just measuring its surface is often not good enough. At some point, Benedetto mentioned his group's microneedle work with plants, and we realized that we could combine our expertise to make a more effective sensor," Hart recalls.The team looked to create a sensor that could pierce through the surface of many types of food. The design they came up with consisted of an array of microneedles made from silk."Silk is completely edible, nontoxic, and can be used as a food ingredient, and it's mechanically robust enough to penetrate through a large spectrum of tissue types, like meat, peaches, and lettuce," Marelli says.To make the new sensor, Kim first made a solution of silk fibroin, a protein extracted from moth cocoons, and poured the solution into a silicone microneedle mold. After drying, he peeled away the resulting array of microneedles, each measuring about 1.6 millimeters long and 600 microns wide -- about one-third the diameter of a spaghetti strand.The team then developed solutions for two kinds of bioink -- color-changing printable polymers that can be mixed with other sensing ingredients. In this case, the researchers mixed into one bioink an antibody that is sensitive to a molecule in The researchers made a bioink containing antibodies sensitive to Kim then embedded pores within each microneedle to increase the array's ability to draw up fluid via capillary action. To test the new sensor, he bought several fillets of raw fish from a local grocery store and injected each fillet with a fluid containing either After about 16 hours, the team observed that the "E" turned from blue to red, only in the fillet contaminated with The researchers also found their new sensor indicates contamination and spoilage faster than existing sensors that only detect pathogens on the surface of foods."There are many cavities and holes in food where pathogens are embedded, and surface sensors cannot detect these," Kim says. "So we have to plug in a bit deeper to improve the reliability of the detection. Using this piercing technique, we also don't have to open a package to inspect food quality."The team is looking for ways to speed up the microneedles' absorption of fluid, as well as the bioinks' sensing of contaminants. Once the design is optimized, they envision the sensor could be used at various stages along the supply chain, from operators in processing plants, who can use the sensors to monitor products before they are shipped out, to consumers who may choose to apply the sensors on certain foods to make sure they are safe to eat.This research was supported, in part, by the MIT Abdul Latif Jameel Water and Food Systems Lab (J-WAFS), the U.S. National Science Foundation, and the U.S. Office of Naval Research.
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Zoology
| 2,020 |
September 9, 2020
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https://www.sciencedaily.com/releases/2020/09/200909114757.htm
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Gut microbiota not involved in the incidence of gestational diabetes mellitus
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Maternal overweight and obesity increase the risk of gestational diabetes mellitus. Gut microbiota composition has recently been associated with both overweight and a range of metabolic diseases. However, it has thus far been unclear whether gut microbiota is involved in the incidence of gestational diabetes.
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A clinical study with the purpose to investigate the impact of two food supplements, fish oil and probiotics (containing Lactobacillus rhamnosus HN001 and Bifidobacterium animalis ssp. lactis 420), on maternal and child health was conducted at the University of Turku and Turku University Hospital in Finland. The microbiota was analysed from fecal samples of 270 overweight and obese women using the state of the art analytical and bioinformatics methods based on deep sequencing metagenomics analysis."Metagenomics is a next-generation sequencing tool that provides species level resolution of the gut microbiota composition. Metagenomics also provides information on the bacterial genes and gives clues about the possible function of the gut microbiota," says Senior Researcher Kati Mokkala from the Institute of Biomedicine of the University of Turku, Finland."Our study shows that gut microbiota composition and function is not involved in the onset of gestational diabetes in overweight and obese women. Also, no difference were found in women with gestational diabetes when compared to women remaining free from the condition," explains Associate Professor Kirsi Laitinen from the Early Nutrition and Health research group.Probiotics have been shown to influence gut microbiota composition, but the impact of the combination of probiotics and fish oil is less well characterized. The women were randomised into four groups to consume two food supplements either as a combination or separately: fish oil + placebo, probiotics + placebo, fish oil + probiotics, or placebo + placebo. The women consumed the supplements from early pregnancy onwards until after the pregnancy."Interestingly, our study revealed that the combination of fish oil and probiotics modulated the composition of gut microbiota particularly in women who did not develop gestational diabetes," Mokkala explains.Whether the gut microbiota of women with gestational diabetes is less amenable for modification by food supplements needs to be confirmed in further studies.
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Zoology
| 2,020 |
September 8, 2020
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https://www.sciencedaily.com/releases/2020/09/200908200522.htm
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Skeletal study suggests at least 11 fish species are capable of walking
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An international team of scientists has identified at least 11 species of fish suspected to have land-walking abilities.
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The findings are based on CT scans and a new evolutionary map of the hillstream loach family, which includes the only living fish species caught in the act of walking: a rare, blind cavefish known as Cryptotora thamicola, or the cave angel fish. Pinpointing which species of hillstream loaches have walking capabilities can help scientists piece together how the first land-walking vertebrates might have come to be.In a new study, researchers from the Florida Museum of Natural History, the New Jersey Institute of Technology, Louisiana State University and Maejo University in Thailand analyzed the bone structure of nearly 30 hillstream loach species, describing for the first time three categories of pelvic shapes. Based on the shape of the bone that connects some loaches' spines to their pelvic fins, the team found that 10 other species of loach shared the cave angel fish's unusually hefty pelvic girdle."Fishes don't usually have any connection between their spine and pelvic fin," said biologist Zachary Randall, manager of the Florida Museum's imaging lab and one of the study's co-authors. "But before, the idea was that the cave angel fish was totally unique. What's really cool about this paper is that it shows with high detail that robust pelvic girdles are more common than we thought in the hillstream loach family."But not all loaches are so gifted: Though more than 100 species of hillstream loach are found throughout Southeast Asia, the cave angel fish is the only one whose walking capabilities have been observed and studied. Its salamander-like wiggle, powered by enlarged ribs bolstered with stabilizing muscle attachments, was first described in Randall said the cave angel fish's walk is a key adaptation for surviving fast-flowing cave streams. It can grip rocky streambeds and move between habitats -- even up waterfalls -- as water levels fluctuate in the dry season. The cave angel fish's increased mobility could help it access well-oxygenated stream regions with few or no occupants. Still, little is known about the species, including what it eats."These loaches have converged on a structural requirement to support terrestrial walking not seen in other fishes," said study lead author and NJIT Ph.D. candidate Callie Crawford in a statement. "The relationships among these fishes suggest that the ability to adapt to fast-flowing rivers may be what was passed on genetically," rather than a set of specific physical characteristics.The team used CT scanning and DNA analysis to trace the evolutionary history of the hillstream loach family and found that, rather than evolving from a single origin, a robust pelvic region appeared several times across the hillstream loach family."Even though the cave angel fish was first described in 1988, this is the first time it's been included in the hillstream loach family tree," Randall said. "With our Thai collaborators and using DNA analysis, we were able to use hundreds of genes to trace how pelvic shapes in these fish have evolved over time. Now, we have a much more accurate tree that adds a framework for studying how many species can walk and the extent to which they're able to.""This study brought together a team of researchers with interests and levels of expertise that varied from those of us who do fieldwork and study fishes in their natural habitats to geneticists to comparative anatomists," added Lawrence Page, Florida Museum curator of fishes and a co-principal investigator of the study. "The result is a greatly improved understanding of the evolution of an extremely uncommon event -- the ability of a fish to walk on land."Randall and his team most recently observed the cave angel fish on a 2019 cave excursion in northwest Thailand. Given the rarity of spotting a cave angel fish in the field, Randall said the team was surprised to find six of them clinging to the bed of a fast-flowing shallow stream among glittering stalagmites in one of the cave's chambers. He added that the cave angel fish's rarity meant that museum specimens and CT data were key to mapping the family's evolution."The beauty of CT scanning is that you can capture different types of high-resolution data without compromising the integrity of the specimen," Randall said. "For rare species like this one, it even allows you to capture things that are hard to observe in the field, even what it eats."The team published its work in the
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Zoology
| 2,020 |
September 8, 2020
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https://www.sciencedaily.com/releases/2020/09/200908170529.htm
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Cell in zebrafish critical to brain assembly, function
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New research from Oregon Health & Science University for the first time documents the presence of astrocytes in zebrafish, a milestone that will open new avenues of research into a star-shaped type of glial cell in the brain that is critical for nearly every aspect of brain assembly and function.
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The research was published this week in the journal With their transparent bodies, zebrafish larvae provide a unique opportunity to gaze into the inner workings of the central nervous system, including the brain, even in living animals. The identification of astrocytes and the generation of tools to work with them in zebrafish will enable researchers around the world to open new lines of research to advance scientific understanding of how astrocytes function.Astrocytes, it turns out, are the most abundant and mysterious cell type in the human brain, and OHSU is becoming a hub for research into their roles in development, brain function and disease."There is no neurodegenerative disease that I know of where astrocytes are not profoundly affected in some way," said senior author Kelly Monk, Ph.D., professor and co-director of the Vollum Institute at OHSU. "This gives us a powerful tool to get a handle on what these cells do and how they do it."Monk and co-author Marc Freeman, Ph.D., credit lead author Jiakun Chen, Ph.D., a post-doctoral researcher in the Monk and Freeman labs, with developing a panoply of tools, including a cell-specific approach using the gene editing tool CRISPR to label and manipulate astrocyte precursors and incisively study their development and functions."He was able to capture the birth of an astrocyte from a stem cell and its entire development, which has never been visualized before in a vertebrate animal," Monk said.Freeman said the discovery will dramatically enhance the study of how glia regulate brain development and physiology."This opens the door to experiments that you can't do in any other organism," Freeman said. "Zebrafish is the only animal in which you can now live-image all types of vertebrate glial cells -- astrocytes, microglia, oligodendrocytes and OPCs -- along with any neuron in intact neural circuits, from the earliest stages of development. Zebrafish is also the only vertebrate in which you can image the entire brain in live, behaving animals to figure out how it works. Understanding the role of these cells (astrocytes) in brain development will be key to understanding devastating neurodevelopmental disorders like autism spectrum disorder and schizophrenia."It's a major step forward and should power a lot of exciting work in the coming years."Support for the research was supported by the National Institutes of Health, award R01NS099254, R37NS053538 and R21NS115437.
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Zoology
| 2,020 |
September 8, 2020
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https://www.sciencedaily.com/releases/2020/09/200908085427.htm
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New insights into evolution of gene expression
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Vertebrate organs organize physiological activities, and the diverse expression patterns of thousands of genes determines organ identities and functions. Because of this, the evolution of gene expression patterns plays a central role in organismal evolution.
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Major organ-altering evolutionary events such as development of the hominoid brain are also associated with gene expression shifts. However, although gene duplication is well-known to play an important role in expression pattern shifts, the evolutionary dynamics of expression patterns with and without gene duplication remain poorly understood."An important question is whether long-term expression in one organ predisposes genes to be subsequently utilized in other organs. The answer is yes," says Dr. Kenji Fukushima from Julius-Maximilians-Universität (JMU) Würzburg in Bavaria, Germany. "There are preadaptive propensities in the evolution of vertebrate gene expression, and the propensity varies with the presence and type of gene duplication."Kenji Fukushima now reports this and other findings with his co-author David D. Pollock (University of Colorado, School of Medicine, Aurora, USA) in the journal For their study the scientists amalgamated 1,903 RNA-seq datasets from 182 research projects. The date include six organs (brain, heart, kidney, liver, ovary, and testis) from 21 vertebrate species, ranging from freshwater fish and frogs to lizards, birds, rodents and humans. So they revealed a complex history of gene family trees. This allowed them to analyse the evolutionary expression of a broad set of genes.
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Zoology
| 2,020 |
September 8, 2020
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https://www.sciencedaily.com/releases/2020/09/200908101604.htm
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Gulls pay attention to human eyes
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Herring gulls notice where approaching humans are looking, and flee sooner when they're being watched, a new study shows.
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Researchers approached gulls while either looking at the ground or directly at the birds.Gulls were slower to move away when not being watched -- allowing a human to get two metres closer on average.Newly fledged gulls were just as likely to react to human gaze direction as older birds, suggesting they are born with this tendency or quickly learn it.The study, by the University of Exeter, also confirms the widely held view that urban gulls are bolder than rural gulls -- letting a person get on average 2.5m closer before walking or flying away."Herring gulls are increasingly breeding and foraging in urban areas, and therefore have regular interactions with humans," said lead author Madeleine Goumas, of the Centre for Ecology and Conservation at Exeter's Penryn Campus in Cornwall."We know from previous research that gulls are less likely to peck a bag of chips if a human is watching -- but in that experiment the researcher either looked at the gulls or turned their head away."In our new study, the experimenter approached while facing the gull and only changed the direction of their eyes -- either looking down or at the gull."We were interested to find that gulls pay attention to human eye direction specifically, and that this is true for juveniles as well as adults -- so their aversion to human gaze isn't a result of months or years of negative interactions with people."The study was conducted in Cornwall, UK, targeting adult gulls (aged four years or older, evidenced by white and grey plumage) and juveniles (born in the year of the study, with completely brown plumage).A total of 155 gulls were included in the findings: 50 adults and 45 juveniles in urban settlements, and 34 adults and 26 juveniles in rural settlements.As well as being quicker to flee, rural gulls were also more than three times as likely to fly -- rather than walk -- away from an approaching human, suggesting they are less used to being approached."The growing number of herring gulls in urban areas may make them appear more common than they really are," Goumas said."The species is actually in decline in the UK, and we hope our ongoing research into human-gull interactions will contribute to conservation efforts."
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Zoology
| 2,020 |
September 7, 2020
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https://www.sciencedaily.com/releases/2020/09/200907112342.htm
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Acorn woodpeckers wage days-long battles over vacant territories, radio tag data show
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When acorn woodpeckers inhabiting high-quality territories die, nearby birds begin a battle royal to win the vacant spot. Researchers used radio tags to understand the immense effort woodpecker warriors expend traveling to and fighting in these dangerous battles. They also found spectator woodpeckers go to great lengths to collect social information, coming from kilometers around just to watch these chaotic power struggles. The work appears September 7 in the journal
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"When you're approaching a big tree with a power struggle from far away, you'll first hear a lot of acorn woodpeckers calling very distinctly, and see birds flying around like crazy," says first author Sahas Barve, currently a postdoctoral fellow at the Smithsonian National Museum of Natural History. "When you get closer, you can see that there are a dozen or more coalitions of three or four birds fighting and posturing on branches. One group has to beat all the others to win a spot in the territory, which is really, really rare in animals -- even in fantasy novels it usually boils down to one army against the other."The chaos of the battles makes studying behavior using direct observation difficult. But Barve and his team had an advantage: they used new radio telemetry technology that allowed them to track the birds' locations down to the minute. With radio tags, which "sit like a rock-climbing harness with a fanny pack on the woodpecker's back," the researchers could learn how much time was spent fighting at the power struggles and where the warriors came from.Power struggles for co-breeding positions in oak trees with "granaries" -- large acorn storage structures built by the birds consisting of acorns stuffed into thousands of individual holes in the bark -- involve fighting coalitions formed by groups of non-breeding brothers or sisters from neighboring territories. The radio tag data showed that some birds return day after day and fight for ten hours at a time. "We didn't think it could be that long because they have to be away from their home territory," says Barve. "When do they eat? We still don't know."The researchers hypothesized that woodpeckers would fight the hardest for territories closest to their current home, but found that deciding to fight may depend on more complex social cues as they recruit members to join their coalition. "These birds often wait for years, and when there's the right time and they have the right coalition size, they'll go and give it their all to win a really good territory," he says.The woodpeckers' complex social behavior also extends to the other group that comes to power struggles: the spectators. "We never really paid attention to them because we were always fixated on the birds that were actually fighting," Barve says. "We often forget that there are birds sitting on trees watching nearby." His team found that the biggest battles can attract more than 30 birds, or a third of all woodpeckers in the area, with some traveling more than three kilometers to "come with popcorn and watch the fight for the biggest mansion in the neighborhood."The radio tag data also showed that the spectators spend up to an hour a day watching the fights, despite many already having breeding position granaries of their own. For them, the benefits of social information must outweigh the costs of leaving their home territory unattended for considerable amounts of time. Acorn woodpeckers have tight social networks and know everyone's place due to frequent travels to other territories. "If anything is disruptive to that, or if anything weird happens, they want to go check it out," he says. "The spectators are probably as interested in the outcome as the fighter is, although the warriors benefit more directly."There's still a lot researchers don't know about the acorn woodpeckers' complex social structures, but radio telemetry provides a glimpse into their unique social behaviors. "They potentially have friendships, and they probably have enemies," Barve says. "With our radio tag data, we can tell when two birds are at the same place at the same time. The next step is to try and understand how their social networks are shaped, and how they vary across the year."
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Zoology
| 2,020 |
September 7, 2020
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https://www.sciencedaily.com/releases/2020/09/200907112329.htm
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Ancient bony fish forces rethink of how sharks evolved
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Sharks' non-bony skeletons were thought to be the template before bony internal skeletons evolved, but a new fossil discovery suggests otherwise.
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The discovery of a 410-million-year-old fish fossil with a bony skull suggests the lighter skeletons of sharks may have evolved from bony ancestors, rather than the other way around.Sharks have skeletons made cartilage, which is around half the density of bone. Cartilaginous skeletons are known to evolve before bony ones, but it was thought that sharks split from other animals on the evolutionary tree before this happened; keeping their cartilaginous skeletons while other fish, and eventually us, went on to evolve bone.Now, an international team led by Imperial College London, the Natural History Museum and researchers in Mongolia have discovered a fish fossil with a bony skull that is an ancient cousin of both sharks and animals with bony skeletons. This could suggest the ancestors of sharks first evolved bone and then lost it again, rather than keeping their initial cartilaginous state for more than 400 million years.The team published their findings today in Lead researcher Dr Martin Brazeau, from the Department of Life Sciences at Imperial, said: "It was a very unexpected discovery. Conventional wisdom says that a bony inner skeleton was a unique innovation of the lineage that split from the ancestor of sharks more than 400 million years ago, but here is clear evidence of bony inner skeleton in a cousin of both sharks and, ultimately, us."Most of the early fossils of fish have been uncovered in Europe, Australia and the USA, but in recent years new finds have been made in China and South America. The team decided to dig in Mongolia, where there are rocks of the right age that have not been searched before.They uncovered the partial skull, including the brain case, of a 410-million-year-old fish. It is a new species, which they named Minjinia turgenensis, and belongs to a broad group of fish called 'placoderms', out of which sharks and all other 'jawed vertebrates' -- animals with backbones and mobile jaws -- evolved.When we are developing as foetuses, humans and bony vertebrates have skeletons made of cartilage, like sharks, but a key stage in our development is when this is replaced by 'endochondral' bone -- the hard bone that makes up our skeleton after birth.Previously, no placoderm had been found with endochondral bone, but the skull fragments of M. turgenensis were "wall-to-wall endochondral." While the team are cautious not to over-interpret from a single sample, they do have plenty of other material collected from Mongolia to sort through and perhaps find similar early bony fish.And if further evidence supports an early evolution of endochondral bone, it could point to a more interesting history for the evolution of sharks.Dr Brazeau said: "If sharks had bony skeletons and lost it, it could be an evolutionary adaptation. Sharks don't have swim bladders, which evolved later in bony fish, but a lighter skeleton would have helped them be more mobile in the water and swim at different depths."This may be what helped sharks to be one of the first global fish species, spreading out into oceans around the world 400 million years ago."
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Zoology
| 2,020 |
September 7, 2020
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https://www.sciencedaily.com/releases/2020/09/200904100618.htm
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Fatty acid receptor involved in temperature-induced sex reversal of Japanese medaka fish
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A research collaboration based at Kumamoto University (Japan) has found that activation of PPARα, a fatty acid receptor that detects fatty acids in cells and regulates physiological functions, causes masculinization of Japanese rice fish (medaka). The discovery of this molecular mechanism is expected to advance the development of new sex control technologies.
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The sex of mammals is determined in their genes, specifically the XX/XY combination of sex chromosomes. On the other hand, the sex-determination of fish, amphibians, and reptiles is greatly affected by ambient temperature. The medaka (In this study, researchers conducted an RNA sequencing analysis to search for genes activated by high temperature or cortisol. Many genes related to the fatty acid receptor "peroxisome proliferator-activated receptor alpha" (PPARα) were detected, and when a PPARα activator was administered to medaka larvae, XX medaka became male. Furthermore, when knockout medaka with inhibited PPARα function were produced, differentiation into males was completely suppressed, even after the administration of cortisol or a PPARα activator. To the researchers' knowledge, this is the first time that PPARα activation has been shown to be so involved with medaka sex-differentiation by cortisol or an activator."In fish farming for food production, such as flounder or eel, technology that produces only females is sought after because they grow faster than males," said study leader, Professor Takeshi Kitano. "Here, we have revealed the molecular mechanism that induces differentiation into males and we hope that new sexual control technologies using this mechanism will be developed in the future."
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Zoology
| 2,020 |
September 3, 2020
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https://www.sciencedaily.com/releases/2020/09/200903132958.htm
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A 400-year-old chamois will serve as a model for research on ice mummies
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At first glance, the chamois carcass did not seem to Hermann Oberlechner to be an unusual discovery as mountaineers often happen across the remains of wild animals during their high-altitude excursions. However, upon a close inspection of the chamois skin, the Ahrntal alpinist realised that he was faced with a highly unique discovery and informed the relevant ranger.
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The chamois had in fact been protected by the glacier for 400 years and only recently released due to the ice having receded. With the help of the Alpine Army Corps, the chamois mummy was brought back to the valley and entrusted to Eurac Research for scientific study by the Department of Cultural Heritage. Due to their age and state of preservation, the remains are in fact a perfect simulant of a human mummy and will allow researchers to improve the conservation techniques of ice mummies all over the world while determining methods for the safeguarding of ancient DNA -- a mine of valuable information for humanity.In mummified specimens, DNA has often degraded and is present only in minimal amounts. In fact, faced with a new discovery, the first question experts encounter is how to examine the mummy while continuing to preserve it, without damaging its ancient DNA. Every action has irreversible consequences on DNA fragments, which makes experimenting with new techniques on human finds impossible. Contrastingly, an intact animal mummy is a perfect simulant for research -- especially if its conditions are similar to those of the world's other ice mummies, of which Ötzi and the Inca girl Juanita are among the most famous."Thanks to our previous studies we know the optimal physical and chemical parameters for preservation from a microbiological point of view. In the laboratory we will bring the chamois to those conditions and focus on their effects on DNA. With repeated in-depth analysis we will verify what alterations the DNA undergoes when external conditions change," explains Marco Samadelli, conservation expert at Eurac Research. "Our goal is to use scientific data to develop a globally valid conservation protocol for ice mummies. This is the first time an animal mummy has been used in this way," adds Albert Zink, Director of the Institute for Mummy Studies at Eurac Research.Upon encountering the chamois, Hermann Oberlechner soon realised the importance of the find. "Only half of the animal's body was exposed from the snow. The skin looked like leather, completely hairless; I had never seen anything like it. I immediately took a photo and sent it to the park ranger, together we then notified the Department of Cultural Heritage."The discovery site, at 3200 m MSL, is impassable and can only be reached by a six-hour hike. For this reason, following their initial inspection, the researchers decided to ask for the support of the Alpine Army Corps in the recovery of the animal. "The request from Eurac Research came during a training phase of our military mountain rescue team. We plan regular exercises not only in order to always be ready to intervene and protect our personnel in high-altitude missions, but also if we are requested for civil protection too." commented Mario Bisica, Alpine Army Corps Head of Public Information and Communication.The helicopter flight was organised in collaboration with the army's specialised aviation corps, who have their own regiment in Bolzano, with pilots specifically trained to operate at high altitude. Thanks to the group effort, Eurac Research experts were able to reach the glacier and, with the help of the troops, carry out the scientific operation needed to recover the mummy. The chamois was then wrapped in an inert material casing made to measure by conservationist Marco Samadelli. The remains are now being kept at the Eurac Research Conservation Laboratory at NOI Techpark in refrigerated cell at -- 5 C°, ready to be studied.Glacier melt is leading to the increasingly frequent discovery of finds, including biological ones. Under the supervision of Eurac Research anthropologist Alice Paladin, the blanket of fresh snow and thick layer of ice covering the chamois mummy, were removed using various archaeological excavation tools. The precise operation required everyone's collaboration and commitment to avoid any kind of risk, minimise contamination and ensure the find's preservation.
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Zoology
| 2,020 |
September 2, 2020
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https://www.sciencedaily.com/releases/2020/09/200902115926.htm
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Birds can learn from others to be more daring
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House sparrows can be found on nearly every continent including North America, South America, Africa and Australia, where they are not native but an invasive species. New research into these highly social songbirds reveals that they can learn from each other and adapt their behavior.
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"Our study demonstrates that house sparrows can extrapolate information gleaned from the social environment and apply it to new experiences," said Tosha Kelly, LSU Department of Biological Sciences post-doctoral researcher and lead author in this study published in House sparrows can often be observed in large flocks and this research suggests they may watch and learn from each other. The ability of house sparrows to adjust their behavior after a social experience provides evidence of social learning."This is really important because as humans encroach upon and develop wildlife habitats, animals are exposed to a variety of environments and objects that they wouldn't naturally be exposed to. It's critical to understand how quickly new information can pass through a population, which can affect how a species, as a whole, is going to persevere in this era of human-induced environmental change," Kelly said.Kelly and colleagues video recorded, in a lab environment, how individual house sparrows reacted to a new object placed near the food bowl in their cage. Some sparrows did not hesitate to feed at their bowl despite the new object, while others were more reluctant to approach the bowl with the unusual object nearby. The new objects were harmless to the birds and were introduced one at a time. The objects included a blinking light, a white cover over part of the dish, yellow pipe cleaners, a purple plastic egg, a red-painted dish, a tinfoil hood, three gold bells, pink puffs and an open blue cocktail umbrella. Each bird was exposed to three of these objects one at a time to determine its "personality type."The researchers paired 10 individual birds with similar responses to the new objects and 14 birds with contrasting responses to the objects. Then, the pairs were exposed to unusual objects near the food dish that were new to both individuals in each pair's shared cage. Kelly and colleagues observed through video recordings that the more wary individual had the opportunity to observe the more daring individual feed at the bowl near the new object. Then, all of the birds were returned to their individual cages and a week later, they were tested alone again with new objects near the food dish. Surprisingly, the birds that had previously been more cautious but had watched a daring partner began to be more daring when feeding alone at their food bowl, even with a completely new object they had never seen before nearby.A week after being housed with a more daring partner, cautious house sparrows were on average 2.6 times more likely to feed in the presence of a new object than compared to when initially tested alone. This demonstrates that they learned from their partners that novel objects near the food dish were not a threat, write the authors."A lot of species that get introduced don't become established, but house sparrows are very successful. Our findings from this study might be part of what explains their success as an invasive species," said LSU Department of Biological Sciences Assistant Professor Christine Lattin, who is the senior author on this study. "How an individual species responds to novelty can have a big impact on whether or not they can coexist with people in cities and other human-altered environments. It may also indicate whether they are going to be able to benefit from increased food availability and other kinds of opportunities that humans bring along with them or if they are going to just be shut out."
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Zoology
| 2,020 |
September 2, 2020
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https://www.sciencedaily.com/releases/2020/09/200902082335.htm
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Eat more to grow more arms...if you're a sea anemone
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Your genetic code determines that you will grow two arms and two legs. The same fate is true for all mammals. Similarly, the number of fins a fish has and the number of legs and wings an insect has are embedded in their genetic code. Sea anemones, however, defy this rule and have a variable number of tentacle arms.
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Until now it's been unclear what regulates the number of tentacles a sea anemone can grow. Scientists from the Ikmi group at EMBL Heidelberg, in collaboration with researchers in the Gibson lab at the Stowers Institute for Medical Research in Kansas City, have shown that the number of tentacles is defined by the amount of food consumed. "Controlling the number of tentacle arms by food intake makes the sea anemone behave more like a plant developing new branches than an animal growing a new limb," explains group leader Aissam Ikmi. Defining what environmental factors trigger morphological changes is a particularly important question given the longevity of sea anemones, with some species living for more than 65 years. "As predominantly sessile animals, sea anemones must have evolved strategies to deal with environmental changes to sustain such a long lifespan," adds Ikmi.The scientists have shown that the growth of new tentacles happens not only when the sea anemone is a juvenile, but also throughout adulthood. "We can conclude that the number of tentacle arms must be determined by the interplay between genetic and environmental factors," says Ikmi, who started this project when he was still a postdoc in the lab of Matt Gibson. While the sea anemone uses different strategies to build tentacles in the different stages of its life, the final arms are morphologically indistinguishable from each other. "If humans could do the same, it would mean that the more we ate, the more arms and legs we could grow," says Ikmi. "Imagine how handy it would be if we could activate this when we needed to replace damaged limbs."When Ikmi's group studied the locations at which the new arms form, they found that muscle cells pre-mark the sites of new tentacles. These muscle cells change their gene expression signature in response to food. The same molecular signalling employed to build tentacles in sea anemones also exists in many other species -- including humans. So far, however, its role has been studied mainly in embryonic development. "We propose a new biological context in which to understand how nutrient uptake impacts the function of this developmental signalling: a situation that is relevant for defining the role of metabolism in guiding the formation of organs during adulthood" explains Ikmi. "Sea anemones show us that it is possible that nutrients are not converted into excess fat storage -- as it is the case in all mammals -- but instead transformed into a new body structure."While this finding is novel on its own, it also shows that sea anemones, which are traditionally used for evolutionary developmental studies, are well suited to study morphogenesis in the context of organism-environment interactions.To build the branching map of new tentacles, researchers analysed more than 1000 sea anemones one by one. "Scoring such a massive number of tentacles is, in some ways, a story in itself," says Mason McMullen, laughing. McMullen, a clinical pharmacist at the University of Kansas Health System, spent months imaging sea anemones' heads to score their tentacle number and location.Knowing that the number of tentacles in sea anemones is determined by their food intake, the group plans to define the key nutrients critical to this process. Ikmi and his group also want to further investigate the unconventional role of muscles in defining the sites where new tentacles form. "We're currently investigating this novel property of muscle cells and are eager to find out the mystery behind them," he concludes.
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Zoology
| 2,020 |
September 1, 2020
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https://www.sciencedaily.com/releases/2020/09/200901135436.htm
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Small fish populations accumulate harmful mutations that shorten lifespan
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Population bottlenecks contribute to the accumulation of several harmful mutations that cause age-related illnesses in killifish -- a finding that may help answer a key question about aging.
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The study, published today in The very short lives of turquoise killifish -- between three and nine months -- make them an ideal model for studying aging. Killifish live in temporary ponds in Africa that dry up for part of the year, meaning they must hatch, mature and reproduce before this happens. Their eggs survive the dry periods in a hibernation-like state and hatch when rains fill the pond again, starting a new generation."Different wild turquoise killifish populations have varying lifespans, and we wanted to explore the reasons behind this," explains lead author David Willemsen, Postdoctoral Research Fellow at the Max Planck Institute for Biology of Ageing, Cologne, Germany.For their study, Willemsen and senior author Dario Riccardo Valenzano carried out field work in savanna pools in Zimbabwe to catch and collect genome samples from the killifish for sequencing and analysing in the lab. The team then compared the genomes of killifish living in the driest environments, which have the shortest lives, with the genomes of killifish from wetter environments, which live for months longer.The short-lived killifish have very small, often isolated populations, leading to so-called population bottlenecks which, the team found, result in harmful mutations accumulating in their populations. By contrast, the longer-lived killifish have larger populations and new fish with new genetic material frequently join their populations. Over time, these larger populations make it more efficient for natural selection to remove harmful mutations."Limited population sizes caused by habitat fragmentation and repeated population bottlenecks increase the chance for harmful mutations to accumulate in the population," Willemsen says. "Our work may help answer a key question about aging by suggesting that population dynamics, rather than evolutionary selection for or against specific genes, contribute to this accumulation of harmful mutations that result in aging and shorter life."The results support a model where, given the brief rainy seasons, killifish are under strong selective constraints to survive in the absence of water as dormant embryos and to rapidly reach sexual maturation and reproduce before the water completely evaporates. However, the team believes that killifish are not selected to be short-lived. Instead, harmful mutations that affect late-life survival and reproduction (together causing aging in the killifish) accumulate over generations without being constrained by selection."Harmful mutations passively accumulate in killifish populations, and this is even more prominent in smaller populations which happen to live in drier environments," says senior author Dario Riccardo Valenzano, Group Leader at the Max Planck Institute for Biology and Ageing, and Principle Investigator at CECAD, the Cluster of Excellence for Ageing Research at the University of Cologne, Germany. "Our findings highlight the role of demographic constraints in shaping lifespan within species and could potentially be expanded to provide new insights on aging within other animal and human populations."
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Zoology
| 2,020 |
August 27, 2020
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https://www.sciencedaily.com/releases/2020/08/200827122108.htm
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How sticklebacks dominate perch
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A research project on algal blooms along the Swedish coast, caused by eutrophication, revealed that large predators such as perch and pike are also necessary to restrict these blooms. Ecologist Britas Klemens Eriksson from the University of Groningen and his colleagues from Stockholm University and the Swedish University of Agricultural Sciences, Sweden have now shown that stickleback domination moves like a wave through the island archipelagos, changing the ecosystem from predator-dominated to algae-dominated. Their study was published on 27 August in the journal
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Eriksson experimented with the effects of nutrients on algal blooms while working as a postdoctoral researcher in Sweden. When he added nutrients to exclusion cages in the brackish coastal waters, algae began to dominate. This was no surprise. However, when he excluded large predators, he saw similar algal domination. 'Adding nutrients and excluding large predators had a huge effect,' he recalls, 10 years later.The big question that arose from these results using small exclusion cages was whether the results would be the same for the real Swedish coastal ecosystem. This coast consists of countless archipelagos that stretch up to 20 kilometres into the sea, creating a brackish environment. Here, perch and pike are the top predators, feeding on sticklebacks, which themselves eat the small crustaceans that live off algae.To investigate how this food web developed over the past 40 years, Eriksson (who had moved to the University of Groningen in the Netherlands) connected with his colleagues at Stockholm University and the Swedish University of Agricultural Sciences to gather data on fish abundances and to carry out a series of field studies. They were inspired by recent suggestions that regime shifts can occur in closed systems such as lakes and wondered whether algal blooms in the Baltic sea could also be a consequence of such a regime change.Eriksson and his colleagues sampled 32 locations along a 400-kilometre stretch of coastline. 'We visited these sites in the spring and autumn of 2014 and sampled all levels of the food web, from algae to top predators.' These data were subsequently entered into a food web model, which helped them to find connections between species. The models showed that the small sticklebacks were important for the reproduction of the larger predators. And a local increase in sticklebacks means that a lot of the grazers in the ecosystem are eaten, which drives algal domination.'If you just look at the abundances of fish, you find a mixed system in which different species dominate,' Eriksson explains. But looking at the changes in these fishery data over time showed an increase in sticklebacks that started in the late 1990s, initially in the outer parts of the archipelagos. 'This is presumably caused by a reduction in the number of large predators. The reduction is the combined result of habitat destruction, fishing and increased predation by cormorants and seals.' Sticklebacks migrate from the outer archipelagos inwards to reproduce, linking coastal and offshore processes.Reduced predation increases the survival of sticklebacks, while both eutrophication and warming help to increase their numbers even further. As the sticklebacks reduced the number of grazers, algae began to replace seagrass and other vegetation. Furthermore, the sticklebacks also fed on the larvae of perch and pike, thereby further reducing their numbers. 'This is a case of predator-prey reversal,' explains Eriksson. Instead of top predators eating sticklebacks, the smaller fish strongly reduced the number of perch and pike larvae.Over time, the stickleback domination moved inwards like a wave: regional change propagated throughout the entire ecosystem. This has important consequences for ecosystem restoration. 'To counter algal blooms, you should not only reduce the eutrophication of the water but also increase the numbers of top predators.' It means that those organizations that manage fisheries must start working together with those that manage water quality. 'We should not look at isolated species but at the entire food web,' says Eriksson. 'This is something that the recent EU fishery strategy is slowly starting to implement.'Furthermore, the propagation of local changes throughout a system has wider implications in ecology, especially in natural ecosystems that have complex interaction and information pathways. 'And we know this from politics and human behaviour studies. A good example is the Arab Spring, which started locally and then propagated across the Middle East.'
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Zoology
| 2,020 |
August 27, 2020
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https://www.sciencedaily.com/releases/2020/08/200827122105.htm
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Decoded: The structure of the barrier between three cells
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Organs in animals and in humans have one thing in common: they are bounded by so-called epithelial cells. These, along with the muscle, connective and nervous tissues, belong to the basic types of tissue. Epithelial cells form special connections with one another in order to prevent substances or pathogens from passing between the cells, i.e. they have a protective and sealing function for the body. Researchers at the Institute of Animal Physiology at the University of Munster have now found out how two proteins called Anakonda and M6 interact in epithelial cells in fruit flies in order to produce a functioning barrier at so-called tricellular contacts.
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These corner points between three cells -- so-called tricellular junctions (TCJs) -- are a preferred route for migrating cells as well as for bacterial pathogens entering into the body. Although the formation of the barrier function between two epithelial cells has already been well examined, much less is known about the biology of the tricellular contacts. The working group headed by Prof. Dr. Stefan Luschnig is aiming to gain a better understanding of the structure and dynamics of epithelial barriers, hoping that this can contribute in the long term to developing more effective forms of diagnosis and treatment for example of bacterial infections or inflammation reactions. The study has been published in the journal "TCJs play an essential role in the functioning of the barrier between epithelial cells and in the migration of cells across tissue boundaries. Special protein complexes at the tricellular contacts are responsible for the sealing properties of these structures. Despite the fundamental roles of tricellular contacts in epithelial biology, their molecular structure and the dynamics of their assembly and remodelling have so far been insufficiently understood.In order to study this process, the researchers visualized the M6 protein in embryos of the fruit fly Drosophila with a fluorescent marker and, using a high-resolution confocal microscope, they observed the processes taking place in the tricellular contacts in the living cells. As a result of their studies, Stefan Luschnig and his team discovered that the M6 protein is responsible for keeping the Anakonda protein stable in its place at the cell membrane of the TCJs.When the researchers removed the M6 protein, the Anakonda protein -- though it still reached its destination at the cell membrane -- was not anchored stably there. The consequence is a permeable tricellular junction. These and other findings led the researchers to conclude that the two proteins depend on each other and form a complex, which is of crucial importance for the stabilising properties of cell contacts and consequently for survival of the animal. "On the basis of these results obtained from the model organism Drosophila," says Stefan Luschnig, "we can gain fundamental insights into the structure and development of epithelial tissues in more complex animals, as well as in humans."
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Zoology
| 2,020 |
August 27, 2020
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https://www.sciencedaily.com/releases/2020/08/200824105531.htm
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Birds of a feather flock together, but timing depends on typhoons
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Six black-naped terns -- a coastal seabird found in the Pacific and Indian Oceans -- have given researchers a glimpse into how they navigate tropical typhoons.
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The research team based in Japan published their analysis on May 30 in "Our goal was to examine the migration characteristics of the black-naped terns from the Okinawa Islands," said paper author Jean-Baptiste Thiebot, project researcher at the National Institute of Polar Research (NIPR) in Japan. "The bird is listed as vulnerable by Japan's Ministry of Environment."Thiebot and the team were specifically interested in finding where the birds spend their winters and how they manage to cross the Philippine Sea. The body of water lays just south of Japan, covering an area of two million square miles that suffers from frequent and strong typhoons."The birds have to cross the Philippine Sea during the peak of typhoon season," Thiebot said.The birds nest near Okinawa in mid-May, lay their eggs in June, and the hatchlings are ready to leave the nest near the end of August. The adults then spend September traveling to their wintering sites south of the Philippine Sea -- but, it appears the time and path of travel depends on typhoon season.The researchers outfitted a total of 20 terns with geographic logging trackers in 2012 and 2017. Of those 20, the researchers were able to collect movement data from two terns from 2012 to 2014 and from four birds from 2017 to 2018."The two birds tracked in years of medium-high typhoon activity from 2012 to 2014 seemed to target a stopover area in the northern Philippines several days after a typhoon hit," Thiebot said. "By contrast, in 2017, no strong typhoon hit in August, and the four study birds departed 23.8 days later, but moved significantly quicker with little or no stopover."Despite when they left the breeding grounds, the birds always arrived in the Indonesian islands south of the Philippine Sea within four days of October 1."The terns seemed to adjust the timing and path of their migration according to the level of typhoon activity," Thiebot said. "It is likely that terns respond to the typhoon activity because the storms modify the birds' feeding conditions at the water surface."The terns may use environmental cues, such as the low infrasound storms emit, to time their migration, according to Thiebot. The researchers plan to record the infrasound levels at the breeding area to test this hypothesis, and they hope to further study the terns' migration across years of typhoon activity to refine their understanding.This work was supported by the 'Monitoring Sites 1000 Project' of the Ministry of the Environment, and it was funded by the Suntory Fund for Bird Conservation (2017-19) and Bird Migration Research Center, Yamashina Institute for Ornithology in 2012.Other contributors include Noboru Nakamura, Naoki Tomita and project leader Kiyoaki Ozaki, all of whom are affiliated with the Yamashina Institute for Ornithology; and Yutaka Toguchi of Koboh Ryukyurobin.
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Zoology
| 2,020 |
August 26, 2020
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https://www.sciencedaily.com/releases/2020/08/200826183538.htm
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Following 'Eatwell Guide' diet could reduce your risk of dying early and lower your environmental footprint
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The research was led by the London School of Hygiene & Tropical Medicine, in collaboration with the University of Oxford and funded by the Wellcome Trust.
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It found that people who adhered to any five or more of the evaluated recommendations set out in the guidelines had an estimated 7% reduction in their mortality risk -- based on data from three major UK databases (UK Biobank, EPIC Oxford and the Million Women Study).They also found that the recommendation associated with the largest reduction, when adhered to alone, was the consumption of fruit and vegetables which reduced estimated risk by 10%.Additionally, the study showed that following Eatwell Guide recommendations could reduce the emission of greenhouse gases -- one of the biggest drivers of climate change. Diets that adhered to between five and nine of the evaluated recommendations were associated with 1.6kg less COHowever, data from the National Diet and Nutrition Survey revealed that less than 0.1% of people adhered to all nine guidelines. The majority of people (44%) followed three or four of the recommendations, with the consumption of dietary fibre and oily fish being the least commonly met category.Globally, around 1.9 billion adults are overweight or obese, 462 million are underweight and a third are suffering from essential nutrient deficiencies. Governments are putting more emphasis on the need for a balanced, healthy diet -- especially one which is more sustainable and environmentally friendly.The government's current Eatwell Guide (EWG), published in 2016, provides advice on balanced and healthy diets. The recommendations include advice to consume five portions of fruit and vegetables per day, wholegrain, higher fibre carbohydrates and lower fat and sugar dairy options. The EWG also recommends consumption of no more than 70g of red and processed meat a day, and replacing meat with lower fat, higher fibre proteins such as beans, pulses, fish and eggs.Other recommendations include choosing unsaturated oils and spreads, limiting consumption of foods high in fat, salt and sugar, and drinking six to eight glasses of fluid every day.Previous studies have shown that fruit, vegetable and fibre consumption, in combination with limited sugar and processed meat intake, is associated with improved cardiovascular health and reduced cancer risk.Dr Pauline Scheelbeek, Assistant Professor in Nutritional and Environmental Epidemiology at the London School of Hygiene & Tropical Medicine (LSHTM) and study lead author, said:"Our study demonstrates that the Eatwell Guide forms an effective first step towards more healthy and sustainable diets in the UK. Further adherence to the guidelines would not only result in population health benefits, but is also associated with lower environmental footprint due to reduced greenhouse gas emission."However, more transformational dietary shifts than those recommended in the Eatwell Guide will be necessary if we want to meet the Paris Agreement targets."The Eatwell Guide does not specifically target environmental sustainability of diets. We therefore need to investigate ways to further reduce environmental footprints of our diets in ways that would be culturally acceptable and could be implemented by the UK population, both from a consumption and a production side, without compromising population health."The research team used greenhouse gas emissions and water footprints -- the amount of ground or surface water a crop or livestock used -- to estimate the total environmental footprint of the diets. The dietary water footprints of those with low to high adherence to the recommendations differed very little.The consumption of red or processed meat has been shown to contribute considerably to greenhouse gas emissions. This study indicates that by limiting how much of them we eat in order to reduce our dietary footprint, instead eating more beans, pulses and sustainably sourced fish which typically have less impact on the environment, the dietary COProfessor Alan Dangour, Director of the Centre on Climate Change and Planetary Health at LSHTM and study senior author, said:"National dietary recommendations provide important evidence-based guidance for people on the components of a healthy diet. Our new analysis demonstrates that following the Eatwell Guide would substantially improve human health in the UK and reduce our nation's footprint on the planet.""Public Health England has an opportunity to reach across government and define national dietary guidelines that meet both health and environmental targets and we urge the UK government to develop a stronger joined-up approach to tackle the impending health and environmental crises."The authors acknowledge limitations in the analysis. The authors did not rank dietary recommendations, and their analyses assumed that all recommendations had equal value, regardless of which were adhered to. Finally, despite the fact that large UK-based studies were used for this analysis, the exact impact of adhering to specific dietary guidelines on disease and mortality risk is subject to some uncertainty.
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Zoology
| 2,020 |
August 26, 2020
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https://www.sciencedaily.com/releases/2020/08/200825110604.htm
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First review of SARS-CoV-2 and COVID-19 infection models aims to fast track research
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An international collaboration between leading respiratory scientists, immunologists and clinicians, led by Centenary UTS Centre for Inflammation, has completed the first comprehensive review of all relevant animal and cellular models of SARS-CoV-2 infection and COVID-19.
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The review, published in The researchers say that clinical trials have been hampered by the lack of this type of information derived from fundamental research.Lead author, Dr Matt Johansen from Centenary UTS Centre for Inflammation said that everyone understands COVID-19 is causing a major "once-in-a-century global pandemic" and that there is a race to develop vaccines and identify the most effective treatments."Using representative animal models of SARS-CoV-2 infection, including in the background of chronic diseases such as obesity and diabetes, with validation of findings in primary human cells and tissues is the most efficient strategy," Dr Johansen said."By discussing all the available models and their pro's and con's, this will enable other readers to make informed decisions about the advantages of each model and the suitability to their applications," he said.Among the key points of the review are that the clearest predictor of mortality is age, with the case fatality rate rising dramatically over 60 years of age. Other predisposing factors for heightened mortality are being male, social deprivation, and chronic disease particularly chronic obstructive pulmonary disease (COPD), cardiovascular disease (CVD), obesity and diabetes.Director of the Centenary UTS Centre for Inflammation and senior author, Professor Phil Hansbro said "Understanding the complex interactions between people with underlying diseases is critical to finding the most effective treatments for those susceptible individuals.""A key issue is why some individuals progress to more severe lower respiratory disease but others do not, and currently scientists aren't really sure why.""Within the Centre for Inflammation, one of the things we are trying to do is use cellular and animal models to comprehensively decipher why some people get more severe disease than others" Prof Hansbro said.Other institutions involved in the study are Zhejiang University-University of Edinburgh Institute (Hangzhou, China), Institut Pasteur (Paris, France), Hudson Institute of Medical Research (Victoria, Australia), Monash University (Victoria, Australia), Monash Children's Hospital (Victoria, Australia), Hunter Medical Research Institute and University of Newcastle (NSW, Australia), University of Queensland (QLD, Australia), The University of Sydney and Royal Prince Alfred Hospital (NSW, Australia), Centenary Institute (NSW, Australia), ANZAC Research Institute (NSW, Australia).
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Zoology
| 2,020 |
August 26, 2020
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https://www.sciencedaily.com/releases/2020/08/200826101632.htm
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How are information, disease, and social evolution linked?
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Animals use social information for a variety of reasons, including identifying new foraging areas or of threats from predators.
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However, gaining this information requires physical contact among individuals, an action that risks spreading contagion. This leads to an evolutionary trade-off: what information does an individual stand to gain at the risk of possible infection?Both social information and disease transmission are governed by our social structures, shaping how we live. Yet information and infection are rarely investigated as interactive factors driving social evolution.Publishing in "We live in an increasingly connected world, and these connections bind us together in nature," explains study coauthor Andrew MacIntosh."As such, we have always had to navigate the costs and benefits of social relationships, an experience that is shared with myriad other organisms that live in groups."But what governs the structures of our social worlds? Sharing information and cooperation ties us together, but the current global pandemic reminds us that there are limits to our social connectedness, demanding changes in our behavior."Social animals face two key needs: access to information about key resources, and avoidance of pathogens that can make them sick," continues lead author Valéria Romano.The team began by reviewing literature on social transmission and the strategies employed by animals to reduce the costs of connectedness. They found examples where evolution has resulted in potential solutions to our ongoing social dilemmas protecting us from infectious diseases.Common strategies include individuals self-isolating, or uninfected individuals actively avoiding infected peers.The team then introduced an integrative theoretical framework for studying social structure as a dynamic system in which individuals constantly update their social behaviors to reflect both the benefits and costs of interaction."British zoologist Robert Hinde -- one of the great thinkers in animal behavior -- established an evolutionary framework for studying the structures of animal societies," explains coauthor Cédric Sueur."But he missed assigning a role for deleterious forms social transmission, like infectious diseases. By extending our analysis of 'connection costs' to Hinde's analysis, we've modernized his classic model."Although humans have evolved with and developed tools to protect ourselves from the spread of diseases, our own social networks are embedded within a much broader ecological network."Covid-19 is the product not only of the global reach of our interactive networks, but also of our incautious exploitation of the natural world," MacIntosh concludes."Social distancing and digital communication can slow the spread of pathogens, but more responsible interaction with nature might have mitigated its emergence altogether."
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Zoology
| 2,020 |
August 25, 2020
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https://www.sciencedaily.com/releases/2020/08/200825110629.htm
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How zebrafish maintain efficient and fair foraging behaviors
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New insight on how zebrafish achieve near-optimal foraging efficiency and fairness among groups has been published today in the open-access journal
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The findings, based on analysis of the joint swimming patterns of individual zebrafish and groups, and detailed mathematical models of their behaviour, suggest that specialised social interactions allow the animals to forage efficiently and result in more equal distribution of food among group members.Living in a group has clear benefits, including the sharing of responsibilities and resources. Understanding the interactions among individuals that give rise to group behaviour is therefore central to studying and analysing collective behaviour in animal groups and other biological systems."In real-world situations, animals are likely to encounter several food sources or threats, where maintaining a tight group may not be beneficial for all group members," explains lead author Roy Harpaz, who was a PhD student at the Weizmann Institute of Science, Israel, at the time the study was carried out, and is now Postdoctoral Fellow at Harvard University, Cambridge, US. "Indeed, schooling and shoaling species have been shown to disperse when confronted with distributed resources. We aimed to characterise group foraging in complex environments and map the functional interactions among group members."Harpaz and his PhD advisor, Elad Schneidman of the Weizmann Institute, studied free foraging by groups of adult zebrafish in an open arena. They tracked the foraging behaviours of single adult zebrafish and of groups of three or six fish in a large circular arena with shallow water, where small food flakes were scattered on the surface. Tracking these activities revealed that fish picked up on their shoal mates' swimming maneuvers which indicated the presence of food, and responded by swimming to these locations.The team then compared the predictive power of a family of mathematical models, based on inferred functional and social interactions between zebrafish. The model which accurately described individual and group foraging behaviours suggests that the interactions among fish allow them to combine individual and social information to achieve near-optimal foraging efficiency and promote more equal food intake within groups."Of the different social models we tested, only the one based on the social interactions we inferred from observing real fish results in improved efficiency and equality," Harpaz says. "Also, our model shows that the interactions that would maximise efficiency in these social foraging models depend on group size, but not necessarily on food distribution. We therefore hypothesise that fish adaptively pick the subgroup of neighbours they 'listen to' to determine their own behaviour.""Building accurate models of individual behaviour of groups of fish allowed us to infer the details of effective social interactions among them and reveal a highly efficient and robust foraging strategy," concludes senior author Elad Schneidman. "This work is an example of the power of using detailed analyses of individuals in real groups to build data-driven models of social interactions, and of using these models to link the actions of individual animals to the collective behaviour of a group."
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Zoology
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