Date
stringlengths 11
18
| Link
stringlengths 62
62
| Title
stringlengths 16
148
| Summary
stringlengths 1
2.68k
| Body
stringlengths 22
13k
⌀ | Category
stringclasses 20
values | Year
int64 2k
2.02k
|
|---|---|---|---|---|---|---|
June 1, 2017 | https://www.sciencedaily.com/releases/2017/06/170601135645.htm | Sour taste cells detect water | New research from Caltech shows that sour-sensing taste cells play an important role in detecting water on the tongue. | The work, appearing in a paper in the May 29 issue of the journal "The tongue can detect various key nutrient factors, called tastants -- such as sodium, sugar, and amino acids -- through taste," says Oka. "However, how we sense water in the mouth was unknown. Many insect species are known to 'taste' water, so we imagined that mammals also might have a machinery in the taste system for water detection."Taste cells relay information about tastants to the brain via nerves called the taste nerves. First author and graduate student Dhruv Zocchi measured the electrical responses from taste nerves in mice to various tastants as well as to water. The nerves responded in predictable ways to different basic tastes -- sweet, sour, bitter, salty, and umami -- but they were also stimulated by pure water. "This was exciting because it implied that some taste cells are capable of detecting water," Zocchi says.Each basic taste is mediated by distinct subsets of taste cells. In order to test which taste cells respond to water, the team genetically and pharmacologically blocked the function of individual cell fopulations. For example, when the salt taste receptor was blocked, salt no longer triggered activity in taste nerves, but responses to other tastes were not affected. "To our surprise, when we silenced sour taste cells, water responses were also completely blocked," Oka says. "The results suggested that water is sensed through sour taste cells."To prove that the sour cells indeed contribute to water detection, the team used a technique called optogenetics that allowed them to stimulate sour cells with light instead of water. The researchers removed water from the animals' water bottle and made it so that the bottle's spout emitted a blue light when the animals touched it. They discovered that thirsty genetically engineered mice would go to the spout for water, encounter the light, and "drink" it. Though the mice were not rehydrated, they kept licking the water source because the light created a sensory cue of water.A sour taste is often associated with an unpleasant taste quality that reduces animals' preference toward fluid -- for example, mice avoid drinking lemon juice. Interestingly, when the team stimulated sour cells with light, they did not observe that kind of aversive behavior in the engineered mice."These results raise the question: What information about taste are sour cells really relaying to the brain?" Zocchi says. "Maybe sour cells are not directly linked to the unpleasant sourness that we perceive, but instead they may induce a different type of taste, like water, when stimulated.""It's important to note that stimulation of these cells does not alleviate thirst," says Oka. "But this finding helps us understand how the brain interprets water signals under normal and thirsty states. Next, we would like to tackle the mechanisms by which the hedonic value or 'pleasantness' of sensory inputs are regulated by brain activity." | Genetically Modified | 2,017 |
May 29, 2017 | https://www.sciencedaily.com/releases/2017/05/170529133711.htm | Remembrance of things past: Bacterial memory of gut inflammation | The microbiome, or the collections of microorganisms present in the body, is known to affect human health and disease and researchers are thinking about new ways to use them as next-generation diagnostics and therapeutics. Today bacteria from the normal microbiome are already being used in their modified or attenuated form in probiotics and cancer therapy. Scientists exploit the microorganisms' natural ability to sense and respond to environmental- and disease-related stimuli and the ease of engineering new functions into them. This is particularly beneficial in chronic inflammatory diseases like inflammatory bowel disease (IBD) that remain difficult to monitor non-invasively. However, there are several challenges associated with developing living diagnostics and therapeutics including generating robust sensors that do not crash and are capable of long-term monitoring of biomolecules. | In order to use bacteria of the microbiome as biomarker sensors, their genome needs to be modified with synthetic genetic circuits, or a set of genes that work together to achieve a sensory or response function. Some of these genetic alterations may weaken or break normal signaling circuits and be toxic to these bacteria. Even in cases where the probiotic microbes tolerate the changes, the engineered cells can have growth delays and be outcompeted by other components of the microbiome. As a result, probiotic bacteria and engineered therapeutic microbes are rapidly cleared from the body, which makes them inadequate for long period monitoring and modulation of the organism's tissue environment.A team at the Wyss Institute of Biologically Inspired Engineering led by Pamela Silver, Ph.D., designed a powerful bacterial sensor with a stable gene circuit in a colonizing bacterial strain that can record gut inflammation for six months in mice. This study offers a solution to previous challenges associated with living diagnostics and may bring them closer to use in human patients. The findings are reported in Silver, who is a Core Faculty member at the Wyss Institute and also the Elliot T. and Onie H. Adams Professor of Biochemistry and Systems Biology at Harvard Medical School, thought of the gut as a first application for this system due to its inaccessibility by non-invasive means and its susceptibility to inflammation in patients suffering from chronic diseases like IBD. "We think about the gut as a black box where it is hard to see, but we can use bacteria to illuminate these dark places. There is great interest from patients and doctors that push us to build sensors for biomarkers of gut conditions like IBD and colon cancer," said Silver, "We believe that our work opens up enormous possibilities that can exploit the flexibility and modularity of our diagnostic tool and expand the use of engineered organisms to a wide variety of applications."Key to the team's work is the introduction of a memory module to the circuit that is able to detect a molecule of interest and respond to this exposure long after the stimulus is gone. As bacteria can be rapidly cleared from the intestinal tract, the team used a strain of bacteria that is part of the microbiome of mice, and engineered it to contain the sensory and memory elements capable of detecting tetrathionate. Tetrathionate is a transient metabolic molecule produced in the inflamed mouse intestine as a result of either infection with pathogenic bacteria like The synthetic genetic circuit designed by the Wyss team contains a "trigger element" that is adopted from the natural system specifically recognizing the biomarker (in this case tetrathionate) in cells, or that can be developed using synthetic approaches when no prior sensor exists. The second element in the circuit is the "memory element" that resembles a toggle switch and has been adapted from a virus that attacks bacteria. It consists of two genes (A and B for simplicity) that regulate each other depending on whether the stimulus is present. In the tetrathionate sensor, the product of gene A blocks expression of gene B when tetrathionate is absent. When tetrathionate is produced during inflammation and is sensed by the trigger element, levels of A decrease and the gene B is induced and begins to shut off expression of gene A. The expression of the B gene is also coupled to a reporter gene which turns bacteria from colorless to blue only when they have switched the memory element on. The switch can be maintained in the on state long after the first tetrathionate exposure.After verifying the functionality of the sensor in a liquid culture of bacteria, David Riglar, Ph.D., the study's first author, was able to show that it detected tetrathionate in a mouse model of gut inflammation caused by infection with S. typhimurium up to six months after administration of the sensor-containing probiotic bacteria. Through simple analysis of fecal matter, the synthetic circuit's memory state was confirmed to be on and its DNA unchanged and stable. "Our approach is to use the bacteria's sensing ability to monitor the environment in unhealthy tissue or organs. By adding gene circuits that retain memory, we envision giving humans probiotics that record disease progression by a simple and non-invasive fecal test," said Riglar.Silver's team plans to extend this work to sensing inflammation in the human gut and also to develop new sensors detecting signs of a variety of other conditions."Pam's work demonstrates the power of synthetic biology for advancing medicine as it provides a way to rationally and rapidly design sophisticated sensors for virtually any molecule. If successful in humans, their technology would offer a much less expensive and more specific way to monitor gut function at home than sophisticated imaging instruments used today," said Donald Ingber, M.D., Ph.D., Founding Director of the Wyss Institute, the Judah Folkman Professor of Vascular Biology at Harvard Medical School and the Vascular Biology Program at Boston Children's Hospital, as well as Professor of Bioengineering at the Harvard John A. Paulson School of Engineering and Applied Sciences. | Genetically Modified | 2,017 |
May 25, 2017 | https://www.sciencedaily.com/releases/2017/05/170525141607.htm | Viral protein may help chickenpox virus spread within the body | The virus that causes chickenpox -- varicella zoster virus (VZV) -- possesses a protein that could enhance its ability to hijack white blood cells and spread throughout the body, according to new research published in | The findings, presented by Víctor González-Motos of Hannover Medical School, Germany, and colleagues, may provide new insight into the poorly understood mechanism by which VZV spreads after initial infection in the respiratory tract.VZV causes chickenpox in children and can reactivate later in life to cause shingles. After infecting the respiratory tract, the virus hijacks the immune system's white blood cells, using them to spread in the body -- including to the skin to cause chickenpox.To better understand this process, the researchers investigated whether VZV influences the function of chemokines, small immune system proteins that attract white blood cells to sites of infection and guide their movement within the body.The scientists focused on a VZV protein known as glycoprotein C, since previous research suggested it may play an important role in the infection cycle. In the lab, they performed chemotaxis experiments and found that the addition of glycoprotein C enhances the ability of chemokines to attract white blood cells, including white blood cells from the tonsils, which are a major target of VZV during initial infection.Further experiments uncovered the molecular details of the interaction between glycoprotein C and chemokines. The researchers also showed that VZV viral particles that had been genetically engineered to remove glycoprotein C had a reduced ability to enhance chemokine attraction of white blood cells, indicating the importance of glycoprotein C for this process.Overall, these results suggest that glycoprotein C may interact with chemokines to attract more white blood cells to the site of VZV infection, where the virus can hijack the white blood cells to spread to other parts of the body. Further research is needed to investigate whether this hypothesis holds up in human tissue. | Genetically Modified | 2,017 |
May 18, 2017 | https://www.sciencedaily.com/releases/2017/05/170518140232.htm | Brain blood vessel lesions tied to intestinal bacteria | A study in mice and humans suggests that bacteria in the gut can influence the structure of the brain's blood vessels, and may be responsible for producing malformations that can lead to stroke or epilepsy. The research, published in | Cerebral cavernous malformations (CCMs) are clusters of dilated, thin-walled blood vessels that can lead to seizures or stroke when blood leaks into the surrounding brain tissue. A team of scientists at the University of Pennsylvania investigated the mechanisms that cause CCM lesions to form in genetically engineered mice and discovered an unexpected link to bacteria in the gut. When bacteria were eliminated the number of lesions was greatly diminished."This study is exciting because it shows that changes within the body can affect the progression of a disorder caused by a genetic mutation," said Jim I. Koenig, Ph.D., program director at NINDS.The researchers were studying a well-established mouse model that forms a significant number of CCMs following the injection of a drug to induce gene deletion. However, when the animals were relocated to a new facility, the frequency of lesion formation decreased to almost zero."It was a complete mystery. Suddenly, our normally reliable mouse model was no longer forming the lesions that we expected," said Mark L. Kahn, M.D., professor of medicine at the University of Pennsylvania, and senior author of the study. "What's interesting is that this variability in lesion formation is also seen in humans, where patients with the same genetic mutation often have dramatically different disease courses."While investigating the cause of this sudden variability, Alan Tang, a graduate student in Dr. Kahn's lab, noticed that the few mice that continued to form lesions had developed bacterial abscesses in their abdomens -- infections that most likely arose due to the abdominal drug injections. The abscesses contained Gram-negative bacteria, and when similar bacterial infections were deliberately induced in the CCM model animals, about half of them developed significant CCMs."The mice that formed CCMs also had abscesses in their spleens, which meant that the bacteria had entered the bloodstream from the initial abscess site," said Tang. "This suggested a connection between the spread of a specific type of bacteria through the bloodstream and the formation of these blood vascular lesions in the brain."The question remained as to how bacteria in the blood could influence blood vessel behavior in the brain. Gram-negative bacteria produce molecules called lipopolysaccharides (LPS) that are potent activators of innate immune signaling. When the mice received injections of LPS alone, they formed numerous large CCMs, similar to those produced by bacterial infection. Conversely, when the LPS receptor, TLR4, was genetically removed from these mice they no longer formed CCM lesions. The researchers also found that, in humans, genetic mutations causing an increase in TLR4 expression were associated with a greater risk of forming CCMs."We knew that lesion formation could be driven by Gram-negative bacteria in the body through LPS signaling," said Kahn. "Our next question was whether we could prevent lesions by changing the bacteria in the body."The researchers explored changes to the body's bacteria (microbiome) in two ways. First, newborn CCM mice were raised in either normal housing or under germ-free conditions. Second, these mice were given a course of antibiotics to "reset" their microbiome. In both the germ-free conditions and following the course of antibiotics, the number of lesions was significantly reduced, indicating that both the quantity and quality of the gut microbiome could affect CCM formation. Finally, a drug that specifically blocks TLR4 also produced a significant decrease in lesion formation. This drug has been tested in clinical trials for the treatment of sepsis, and these findings suggest a therapeutic potential for the drug in the treatment of CCMs, although considerable research remains to be done."These results are especially exciting because they show that we can take findings in the mouse and possibly apply them at the human patient population," said Koenig. "The drug used to block TLR4 has already been tested in patients for other conditions, and it may show therapeutic potential in the treatment of CCMs, although considerable research still remains to be done."Kahn and his colleagues plan to continue to study the relationship between the microbiome and CCM formation, particularly as it relates to human disease. Although specific gene mutations have been identified in humans that can cause CCMs to form, the size and number varies widely among patients with the same mutations. The group next aims to test the hypothesis that differences in the patients' microbiomes could explain this variability in lesion number. | Genetically Modified | 2,017 |
May 17, 2017 | https://www.sciencedaily.com/releases/2017/05/170517132941.htm | Same genes, same environment, different personality: Is individuality unavoidable? | Genetically identical Amazon mollies raised individually and under identical environmental conditions, nevertheless develop different personality types. Additionally, increasing the opportunity for social interactions early in life appears to have no influence of the magnitude of personality variation. These results of a recent study by the Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB) shed a new light on the question of which factors are responsible for the individuality of vertebrate animals. | Both the genetics and the environment have an effect on the individual behavior of animals -- or at least that is the common doctrine. But what happens when individuals whose genes are identical are raised in environments that are identical -- do they then develop identical behavioral patterns?A team headed by IGB researchers Dr. David Bierbach and Dr. Kate Laskowski investigated this question in a study, which was published in the journal The IGB team used the Amazon molly, a livebearing Poecilid species. These animals are natural clones, meaning all the offspring of one mother have exactly the same genetic material. Newborn Amazon mollies were placed in three different experimental setups: In the first treatment the animals were kept individually from and under identical conditions from birth. In two other treatments the fish lived for one or three weeks, respectively, in groups of four individuals and were then later separated. After seven weeks, the researchers examined all the Amazon mollies to determine whether and how the individual fish differed in activity and exploratory behavior."We were very surprised to find such distinct personality differences in genetically identical animals that grew up under nearly equal environmental conditions," says Dr. David Bierbach, behavioral ecologist at the IGB and one of the two leading authors of the study. The fish which developed initially in small groups, also showed behavioral differences of nearly the same degree -- no matter whether the development phase with social interactions lasted one or three weeks."Our results suggest that other factors must influence the development of personality in a more substantial way than previously thought: potentially minute differences in environmental conditions, which are impossible to remove completely from any experiment, or potentially epigenetic processes, i.e. random changes of chromosomes and gene functions. Altogether our results suggests that these factors deserve closer inspection as causes of personality variation in future work," explains behavioral ecologist Dr. Kate Laskowski. The IGB study suggests that the development of individuality in vertebrate animals may be an inevitable and ultimately unpredictable result of the developmental process. | Genetically Modified | 2,017 |
May 11, 2017 | https://www.sciencedaily.com/releases/2017/05/170511115938.htm | Rare feline genetic disorders identified through whole genome sequencing | Whole genome sequencing (WGS), which is the process of determining an organism's complete DNA sequence, can be used to identify DNA anomalies that cause disease. Identifying disease-causing DNA abnormalities allows clinicians to better predict an effective course of treatment for the patient. Now, in a series of recent studies, scientists at the University of Missouri are using whole genome sequencing through the 99 Lives Cat Genome Sequencing Consortium to identify genetic variants that cause rare diseases, such as progressive retinal atrophy and Niemann-Pick type 1, a fatal disorder in domestic cats. Findings from the study could help feline preservationists implement breeding strategies in captivity for rare and endangered species such as the African black-footed cat. | The 99 Lives project was established at Mizzou by Leslie Lyons, the Gilbreath-McLorn Endowed Professor of Comparative Medicine in the College of Veterinary Medicine, to improve health care for cats through research. The database has genetically sequenced more than 50 felines and includes DNA from cats with and without known genetic health problems. The goal of the database is to identify DNA that causes genetic disorders and have a better understanding of how to treat diseases.In the first study, Lyons and her team used the 99 Lives consortium to identify a genetic mutation that causes blindness in the African black-footed cat, an endangered species often found in U.S. zoos. The team sequenced three cats ? two unaffected parents and an affected offspring ? to determine if the mutation was inherited or spontaneous. The genetic mutation identified was located the IQCB1 gene and is associated with progressive retinal atrophy, an inherited degenerative retinal disorder that leads to blindness. The affected cat had two copies of the genetic mutation, indicating that it was an inherited disorder."African black-footed cats are closely related to domestic cats, so it was a good opportunity to use the 99 Lives database," Lyons said. "When sequencing DNA, we are looking for the high priority variants, or genetic mutations that result in disease. Variants in the IQCB1 gene are known to cause retinal degeneration in humans. We evaluated each gene of the African black-footed cat, one at a time, to look for the genetic mutation that is associated with vision loss."In another study representing the first time precision medicine has been applied to feline health, Lyons and her team used whole genome sequencing and the 99 Lives consortium to identify a lysosomal disorder in a 36-week-old silver tabby kitten that was referred to the MU Veterinary Health Center. The kitten was found to have two copies of a mutation in the NPC1 gene, which causes Niemman-Pick type 1, a fatal disorder. The NCP1 gene identified is not a known variant in humans; it is a rare mutation to the feline population."Genetics of the patient is a critical aspect of an individual's health care for some diseases," Lyons said. "Continued collaboration with geneticists and veterinarians could lead to the rapid discovery of undiagnosed genetic conditions in cats. The goal of genetic testing is to identify disease early, so that effective and proactive treatment can be administered to patients."Identification of both the IQCB1 gene in the African black-footed cat and the NCP1 in the silver tabby will help to diagnose other cats and allow them to receive appropriate treatment. Using results of the black-footed cat study, zookeepers will be implementing species survival plans to help manage the cats in captivity in North America. | Genetically Modified | 2,017 |
May 11, 2017 | https://www.sciencedaily.com/releases/2017/05/170511113519.htm | Dramatic cooperation between two infectious bacteria | Brucellosis is an infectious disease of livestock that may be transmitted to farm workers or consumers of unpasteurized dairy products. Easy to spread and hard to detect, the bacteria that cause the illness, Brucella species, are considered potential bioterror weapons. Yet, precisely because Brucella species are so dangerous to handle, research on this important disease-causing agent, or pathogen, has lagged behind that of other infectious diseases. | Using an innovative method they developed to study the infectious process, investigators at Beth Israel Deaconess Medical Center (BIDMC) established a safer way to study Brucella. In an early test of the model, the research team observed a surprising and previously undocumented interaction during the infectious process. The presence of another pathogen appeared to improve the infectious potential of Brucella. The report was published in the journal "Our toolkit is simple, versatile and applicable to any type of pathogen," said James Kirby, MD, Director of the Clinical Microbiology Laboratory at BIDMC and Associate Professor of Pathology at Harvard Medical School. "This will be something that will help the scientific community study infectious disease more efficiently going forward because bacterial strains of interest can be constructed so easily, saving a lot of time and effort."Kirby and co-author Yoon-Suk Kang, PhD, a post-doctoral fellow in Kirby's lab used their technique to engineer a special strain of Brucella designed to emit colored light so they could more easily observe it infect host cells the lab.Common in goats, sheep, cattle, pigs and dogs, the four Brucella species capable of infecting humans are classified as potential biothreat organisms that must be studied in designated biosafety level 3 laboratories specially equipped to contain them. But Kirby and Kang, used another Brucella species, B. neotomae -- known to infect only rodents -- to see if it had enough in common with its more dangerous relatives to serve as a safer-to-handle investigational model for all Brucella species.While observing their custom strain, Kirby and Kang witnessed an unprecedented interaction between B. neotomae and Legionella pneumophila, the pathogen that causes Legionnaires' disease in humans.In addition to emitting light, the genetically-altered strain of B. neotomae was also designed to lack the physical structure it needs -- a molecular syringe -- to attack host cells. On their own, these engineered bacteria can't grow and multiply inside the host cell. However, when the host cells were co-infected with this strain of Brucella and L. pneumophila -- also engineered to emit colored light -- at the same time, the harmless B. neotomae thrived. In fact, Kirby notes this de-fanged version of B. neotomae grew better in the presence of L. pneumophila than virulent Brucella normally does without it."Legionella provided all the factors Brucella needs for infection," said Kirby. "It was completely out of the blue. It highlights that pathogens can interact in unexpected ways. The whole is greater than the sum of its parts."The researchers' new technique creates the light-emitting bacteria by introducing genes for fluorescent proteins into their genomes. The concept itself is not new, but the genetic "tool kit" developed by Kirby and Kang greatly streamlines the process by using easy-to-manipulate genes called transposons -- sometimes called jumping genes -- to quickly and safely label the bacteria.Kirby and Kang's technique avoids one significant drawback to traditional means of labeling bacteria for study. Typically, scientists isolate bacteria for study by engineering drug-resistant strains and growing them in a petri dish infused with antibiotics, which will kill any bacteria not relevant to the experiment."That's something we've been concerned about," said Kirby, whose lab also seeks to develop novel antimicrobials as drug-resistant bacteria become an increasing problem globally. "We don't want to make bacteria more resistant to antibiotics. Our toolkit won't confer resistance to anything that might be used in human therapy."This work was supported by grants to Kirby from the National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health, under award numbers R01AI099122, R21AI112694 and R21AI076691. | Genetically Modified | 2,017 |
May 10, 2017 | https://www.sciencedaily.com/releases/2017/05/170510115311.htm | Sugar or protein? How fruit fly brains control what they choose to eat | Using fruit flies, Johns Hopkins researchers say they have identified a specific and very small set of brain cells -- dubbed dopamine wedge neurons -- responsible for driving the insects' food preferences toward what they need, rather than what they like. | When the investigators deprived flies of protein in their diets, those neurons released a chemical signal (dopamine) that appeared to direct the flies craving for their main protein source -- yeast -- overriding their natural tendency to seek out sugar, they report.In a summary of the experiments, published online on May 5 in Although experimenters have identified sensors and hormones in fruit flies and mammals that control how many calories we consume, the Johns Hopkins researchers say they believe this is the first time a protein-specific hunger mechanism has been identified in any animal."We showed that just a few neurons forming a circuit in the fruit fly brain adopts processes used in learning and memory to control persistent, motivated behaviors, food preference in this case," says Mark Wu, M.D., Ph.D., associate professor of neurology at the Johns Hopkins University School of Medicine. Last year, Wu's research team found a similar type of circuit in fruit fly brains that controls sleepiness the longer a fruit fly stays awake.In the search for the neurons that control eating behavior, the researchers used recently mated females that tend to feed on higher protein sources to load up nutrients in their eggs. They searched through different fruit flies lines each engineered using a genetic tool that stopped certain different groups of neurons in the brain from firing. They tested the females from each line for ones that no longer preferred eating high-protein yeast after mating. To measure how much high-protein yeast the flies ate, they put a dye in their yeast food source, then ground up the flies and used an instrument that detects the amount of dye ingested.Initially, Wu's team found a set of dopamine neurons that controlled protein preference. But as they continued to analyze the neurons, they say they were able to assign the food preference signals to just two neurons on each side of the insects' brains in a region referred to as the wedge because of its shape, leading them to call these food preference cells dopamine wedge neurons.The researchers then used tiny electrodes to measure the electrical firing (signaling) behavior of these neurons in fruit flies deprived of protein-rich yeast in their diets. After eight days of protein deprivation, their dopamine-wedge neurons fired four times faster than those in fruit flies fed a normal protein diet.In nature, after protein deprivation, flies tend to seek out high-protein yeast as a food source instead of the fruit sugar they normally prefer for their quick energy boost, so the researchers wondered if the dopamine wedge neurons also suppressed sugar cravings.Using genetically engineered male fruit flies with silenced dopamine wedge neurons, the researchers deprived the flies of high-protein yeast and then measured how much sugar and yeast they ate. Those flies ate on average about twice as much sugar per fly compared with those whose food-preference neurons had not been silenced.When the scientists genetically engineered the dopamine wedge neurons to fire on command, sugar consumption fell to normal levels, whereas protein consumption increased.Wu says there are four dopamine receptors in fruit flies, and the researchers believed that one of more of these were likely involved in controlling food preferences. They looked at food preferences (yeast versus sugar) in each of four fruit fly lines bred to be missing each of these receptors.When given a single food choice, those flies without the DopR2 ate about half as much yeast, and those flies without DopR1 ate double the amount of sugar.Wu's team also searched for structural changes in the dopamine wedge neurons after protein deprivation. They put an additional protein tagged with a green fluorescent protein that hung out on the edges of the neuron at the places where it sends signals to other neurons -- at the synapses.In normally fed fruit flies, the dopamine-wedge neurons had two branches reaching out. But after the flies were deprived of high-protein yeast, they saw one of these branches increase in size and this increase in size persisted for hours after the flies began eating protein."We found that each of these food preference neurons has two branches, one that controls protein feeding and the other sugar feeding," says Wu."Typically flies need sugar as a quick source of calories to fly around, so their neurons bypass the protein circuit," Wu notes. After protein deprivation, they bypass the sugar circuit that makes them seek out protein. "Once you relieve pressure on the protein side by feeding them yeast, the flies can eat sugar again, but they still have a strong craving for protein because it takes time for the fly to replenish its protein stores and for its neuron branches to go back to their original state," he adds.Wu says that his next steps will be to understand the chemical molecules involved in causing the neurons in the hunger circuit to fire, so they can look for similar molecules in mammals like mice or rats. | Genetically Modified | 2,017 |
May 8, 2017 | https://www.sciencedaily.com/releases/2017/05/170508184925.htm | Reversing pest resistance to biotech cotton: The secret is in the mix | Insect pests that are rapidly adapting to genetically engineered crops threaten agriculture worldwide. A new study published in the | The study is the result of a long-standing collaboration between researchers at the University of Arizona and in China. Over 11 years, they tested more than 66,000 pink bollworm caterpillars from China's Yangtze River Valley, a vast region of southeastern China that is home to millions of smallholder farmers.According to the study's authors, this is the first reversal of substantial pest resistance to a Bt crop. "We have seen blips of resistance going up and down in a small area," said senior author Bruce Tabashnik, a Regents' Professor in the UA's College of Agriculture and Life Sciences. "But this isn't a blip. Resistance had increased significantly across an entire region, then it decreased below detection level after this novel strategy was implemented."Cotton, corn and soybean have been genetically engineered to produce pest-killing proteins from the widespread soil bacterium Bacillus thuringiensis, or Bt. These Bt proteins are considered environmentally friendly because they are not toxic to people and wildlife. They have been used in sprays by organic growers for more than 50 years, and in engineered Bt crops planted by millions of farmers worldwide on more than 1 billion acres since 1996. Unfortunately, without adequate countermeasures, pests can quickly evolve resistance.The primary strategy for delaying resistance is providing refuges of the pests' host plants that do not make Bt proteins. This allows survival of insects that are susceptible to Bt proteins and reduces the chances that two resistant insects will mate and produce resistant offspring. Before 2010, the U.S. Environmental Protection Agency required refuges in separate fields or large blocks within fields. Planting such non-Bt cotton refuges is credited with preventing evolution of resistance to Bt cotton by pink bollworm in Arizona for more than a decade. By contrast, despite a similar requirement for planting refuges in India, farmers there did not comply and pink bollworm rapidly evolved resistance.The ingenious strategy used in China entails interbreeding Bt cotton with non-Bt cotton, then crossing the resulting first-generation hybrid offspring and planting the second-generation hybrid seeds. This generates a random mixture within fields of 75 percent Bt cotton plants side-by-side with 25 percent non-Bt cotton plants."Because cotton can self-pollinate, the first-generation hybrids must be created by tedious and costly hand pollination of each flower," said Tabashnik, who also is a member of the UA's BIO5 Institute. "However, hybrids of the second generation and all subsequent generations can be obtained readily via self-pollination. So, the hybrid mix and its benefits can be maintained in perpetuity."Tabashnik calls this strategy revolutionary because it was not designed to fight resistance and arose without mandates by government agencies. Rather, it emerged from the farming community of the Yangtze River Valley. While most previous attention has focused on the drawbacks of interbreeding between genetically engineered and conventional plants, the authors point out that the new results demonstrate gains from such hybridization."For the growers in China, this practice provides short-term benefits," Tabashnik added. "It's not a short-term sacrifice imposed on them for potential long-term gains. The hybrid plants tend to have higher yield than the parent plants, and the second-generation hybrids cost less, so it's a market-driven choice for immediate advantages, and it promotes sustainability. Our results show 96 percent pest suppression and 69 percent fewer insecticide sprays."Although seed mixtures of corn have been planted in the U.S. since 2010, the effects of seed mixtures on pest adaptation were not tested before on a large scale, he explained. "Our study provides the first evidence that planting mixtures of Bt and non-Bt seeds within fields has a resistance-delaying or, in this case, resistance-reversing effect," Tabashnik said.Unlike the strategy in China, the corn seed mixtures planted in the U.S. do not involve interbreeding. Also, the corn seed mixtures have as little as 5 percent non-Bt corn, which may not be enough to battle resistance effectively."This study gives a new option for managing resistance that is very convenient for small-scale farmers and could be broadly helpful in developing countries like China and India," explained coauthor Kongming Wu, who led the work conducted in China and is a professor in the Institute of Plant Protection in Beijing."A great thing about this hybrid seed mix strategy is that we don't have to worry about growers' compliance or regulatory issues," Tabashnik said. "We know it works for millions of farmers in the Yangtze River Valley. Whether it works elsewhere remains to be determined." | Genetically Modified | 2,017 |
May 8, 2017 | https://www.sciencedaily.com/releases/2017/05/170508083419.htm | What silver fir aDNA can tell us about Neolithic forests | A new technique makes it possible to cost-effectively analyse genetic material from fossil plant and animal remains. Researchers from the Swiss Federal Institute for Forest, Snow and Landscape Research WSL and the universities of Lausanne and Bern have used this technique to examine the DNA of silver fir needles found in lake sediment in Ticino. They found clues as to how forests reacted to the emergence of agriculture. | The new process utilises the latest advances in DNA technology to isolate ancient DNA (aDNA) from prehistoric plants and animals. The techniques used to date are, however, expensive. "As population geneticists often need several dozens samples to make reliable statements, many research ideas are not currently financially viable," says Nadir Alvarez, a professor at the University of Lausanne's Department of Ecology and Evolution.The research team led by Alvarez and his colleagues Christoph Sperisen (a population geneticist at the WSL), Willy Tinner (a professor of palaeoecology at the University of Bern) and Sarah Schmid (a biologist from the University of Lausanne) has now developed a cost-effective alternative and demonstrated its potential with subfossil silver fir needles found at Origlio lake in Ticino. The team showcased the results in the research journal Methods in Ecology and Evolution.Working with subfossil genetic material is a challenge. "aDNA is often fragmented, chemically damaged and contaminated with the genetic material of bacteria and fungi," explains Sperisen. "In samples collected in lake sediment, for instance, only every hundredth DNA molecule comes from silver firs." Extracting aDNA is therefore like looking for a needle in a haystack.Until now researchers have extracted aDNA by introducing chemically manufactured counterparts of DNA sequences to the sample solution, as DNA consists of two strands with virtually mirror-image sequences of building blocks attached to one another. Tiny metal beads are attached to the manufactured DNA. Once the artificial DNA is bound to the aDNA, the whole structure can be extracted with a magnet.However, up to over 90% of plant and animal DNA consists of sections with no known function, like a cookbook with mostly blank pages. The new technique, hyRAD-X, does not analyse the entire DNA strand but uses specifically the fraction of the genome that is expressed (i.e. those sections containing the instructions for building a protein). These sections are furthermore generated using an enzyme, an innovation that cuts the cost of an aDNA analysis by tenfold. As every speck of dust contains foreign DNA, this work must be conducted in a clean room, like the one at the WSL's new national plant protection laboratory.The researchers used the new technique to investigate the genetic diversity of silver firs before and during the advent of agriculture at lake Origlio. Palaeobotanist Tinner studied the core of the lake sediment and discovered charcoal deposits as well as cereal pollen and invasive weeds, pointing to the first agricultural activities between 7,500 and 5,000 years ago, when people burned forests to clear space for farmland and pastures. This killed off all of Ticino's heat-loving silver fir stands in the second half of the Holocene; chestnut trees now grow in their place.The results show that the silver fir stand (and thus its genetic diversity) shrank with the dawn of agriculture and recovered around 6,200 years ago. "DNA comparisons of silver firs of varying ages show that the domestic stand genetically regenerated itself afresh without involving silver firs from other regions," says Sperisen.Genetic diversity is key to determining a population's ability to cope with environmental changes. High genetic diversity increases the chances of adapting to a drier climate, for instance. Understanding how ecosystems previously genetically recovered from human intervention indicates how they could react to global climate change and current changes to the way land is used. As such, researchers now want to use the hyRAD-X technique on other subfossil plant samples to clarify, for example, whether the extinct, heat-loving silver fir stands in Ticino had specific genetic properties that could prove important in warmer climates.In 2015, the WSL opened a clean room where researchers work under excess pressure, which prevents pollen, dust or any other impurities from entering the lab. Population geneticists use subfossil material from plants and animals to analyse DNA and thus gain insight into past ecosystems. The clean room is housed in the national plant protection laboratory, which was built by the WSL together with Switzerland's Federal Office for the Environment FOEN and Federal Office for Agriculture FOAG.* Subfossil = any prehistoric organism which has not fossilized, or only partially. Unlike fossils, subfossils can be dated using the C14 method. | Genetically Modified | 2,017 |
May 4, 2017 | https://www.sciencedaily.com/releases/2017/05/170504083229.htm | Scientists engineer baker's yeast to produce penicillin molecules | The synthetic biologists from Imperial College London have re-engineered yeast cells to manufacture the nonribosomal peptide antibiotic penicillin. In laboratory experiments, they were able to demonstrate that this yeast had antibacterial properties against | The authors of the study, which is published in the journal Nonribosomal peptides are normally produced by bacteria and fungi, forming the basis of most antibiotics today. Pharmaceutical companies have long experimented with nonribosomal peptides to make conventional antibiotics. The rise of antimicrobial resistance means there is a need to use genetic engineering techniques to find a new range of antibiotics from bacteria and fungi. However, genetically engineering the more exotic fungi and bacteria- the ones likely to have antibacterial properties -- is challenging because scientists don't have the right tools and they are difficult to grow in a lab environment, requiring special conditions.Baker's yeast on the other hand is easy to genetically engineer. Scientists can simply insert DNA from bacteria and fungi into yeast to carry out experiments, offering a viable new host for antibiotic production research. The rise of synthetic biology methods for yeast will allow researchers to make and test many new gene combinations that could produce a whole new range of new antibiotics.However, the authors are keen to point out that the research is still in its early stages. While this approach does show promise, they have so far produced nonribosomal peptide antibiotic penicillin in small quantities. More research needs to be done to see if it can be adapted to finding other compounds and to get production up to commercially viable quantities.Dr Tom Ellis, from the Centre for Synthetic Biology at Imperial College London, explains: "Humans have been experimenting with yeast for thousands of years. From brewing beer to getting our bread to rise, and more recently for making compounds like anti-malarial drugs, yeast is the microscopic workhorse behind many processes."The rise of drug-resistant superbugs has brought a real urgency to our search for new antibiotics. Our experiments show that yeast can be engineered to produce a well-known antibiotic. This opens up the possibility of using yeast to explore the largely untapped treasure trove of compounds in the nonribosomal peptide family to develop a new generation of antibiotics and anti-inflammatories."Previously, scientists have demonstrated that they could re-engineer a different yeast to make penicillin. However, that species of yeast is not as well understood or amenable to genetic manipulation compared to baker's yeast, used by the authors in today's study, making it less suitable for the development of novel antibiotics using synthetic biology.In their experiments, the team used genes from the filamentous fungus, from which nonribosomal peptide penicillin is naturally derived. These genes caused the yeast cells to produce the nonribosomal peptide penicillin via a two-step biochemical reaction process. First the cells made the nonribosomal peptide base -- the 'backbone' molecule -- by a complex reaction, and then this was modified by a set of further fungal enzymes that turn it into the active antibiotic.During the experimentation process, the team discovered that they didn't need to extract the penicillin molecules from inside the yeast cell. Instead, the cell was expelling the molecules directly into the solution it was in. This meant that the team simply had to add the solution to a petri-dish containing Dr Ali Awan, co-author from the Department of Bioengineering at Imperial College London, explains: "Fungi have had millions of years to evolve the capability to produce bacteria-killing penicillin. We scientists have only been working with yeast in this context for a handful of years, but now that we've developed the blueprint for coaxing yeast to make penicillin, we are confident we can further refine this method to create novel drugs in the future."We believe yeast could be the new mini-factories of the future, helping us to experiment with new compounds in the nonribosomal peptide family to develop drugs that counter antimicrobial resistance."The team are currently looking for fresh sources of funding and new industrial collaborators to take their research to the next level.Dr Ellis added: "Penicillin was first discovered by Sir Alexander Fleming at St Mary's Hospital Medical School, which is now part of Imperial. He also predicted the rise of antibiotic resistance soon after making his discovery. We hope, in some small way, to build on his legacy, collaborating with industry and academia to develop the next generation of antibiotics using synthetic biology techniques." | Genetically Modified | 2,017 |
May 4, 2017 | https://www.sciencedaily.com/releases/2017/05/170504083048.htm | First EPA-approved outdoor field trial for genetically engineered algae | Scientists at the University of California San Diego and Sapphire Energy have successfully completed the first outdoor field trial sanctioned by the U.S. Environmental Protection Agency for genetically engineered algae. | In a series of experiments funded by the U.S. Department of Energy, the researchers tested a genetically engineered strain of algae in outdoor ponds under real-world conditions. As reported in the journal "Just as agricultural experts for decades have used targeted genetic engineering to produce robust food crops that provide human food security, this study is the first step to demonstrate that we can do the same with genetically engineered algae," said Stephen Mayfield, a professor of biology and an algae geneticist at UC San Diego.Under the EPA's purview over a 50-day experiment, the scientists cultured strains of the algae species Acutodesmus dimorphus -- genetically engineered with genes for fatty acid biosynthesis and green fluorescent protein expression -- in parallel with non-engineered algal species. Testing both algae strains in water samples taken from five regional lakes showed strikingly similar levels of growth in the tests, and that the genetic modification did not change the impact of the cultivated strains on native algae communities."This study showed the framework for how this type of testing can be done in the future," said study coauthor Jonathan Shurin, an ecologist in UC San Diego's Division of Biological Sciences. "If we are going to maintain our standard of living in the future we are going to need sustainable food and energy, and ways of making those that do not disrupt the environment. Molecular biology and biotechnology are powerful tools to help us achieve that. Our experiment was a first-step towards an evidence-based evaluation of genetically engineered algae and their benefits and environmental risks.""Progress made in the lab means little if you can't reproduce the phenotype in a production setting," said Shawn Szyjka, the study's lead author, formerly of Sapphire Energy.Future testing will include additional gene types in experiments that run several months, allowing the researchers to further evaluate influences from weather, seasonal shifts and other environmental factors."Algae biomass can address many needs that are key to a sustainable future," said Mayfield, director of the California Center for Algae Biotechnology and the Food and Fuel for the 21st Century initiative. "This is the first of many studies testing this technology in field settings." | Genetically Modified | 2,017 |
May 3, 2017 | https://www.sciencedaily.com/releases/2017/05/170503151935.htm | Modified soybeans yield more in future climate conditions | By 2050, we will need to feed 2 billion more people on less land. Meanwhile, carbon dioxide levels are predicted to hit 600 parts per million -- a 50% increase over today's levels -- and 2050 temperatures are expected to frequently match the top 5% hottest days from 1950-1979. In a three-year field study, researchers proved engineered soybeans yield more than conventional soybeans in 2050's predicted climatic conditions. | "Our climate system and atmosphere are not changing in isolation from other factors -- there are actually multiple facets," said USDA/ARS scientist Carl Bernacchi, an associate professor of plant biology at the Carl R. Woese Institute for Genomic Biology at the University of Illinois. "The effect of carbon dioxide in and of itself seems to be very generalized, but neglects the complexity of adding temperature into the mix. This research is one step in the right direction towards trying to figure out a way of mitigating those temperature-related yield losses that will likely occur even with rising carbon dioxide concentrations."Published in the This work suggests that we can harness genetic changes to help offset the detrimental effects of rising temperature. In addition, Bernacchi said, it illustrates that we cannot deduce complicated environmental and plant systems to increasing carbon dioxide levels increase yields and increasing temperature reduce yields."Experiments under controlled conditions are great to understand concepts and underlying mechanisms," said first author of the study Iris Köhler, a former postdoctoral researcher in the Bernacchi lab. "But to understand what will happen in a real-world situation, it is crucial to study the responses in a natural setting -- and SoyFACE is perfect for this kind of study."SoyFACE (Soybean Free Air Concentration Enrichment) is an innovative facility that emulates future atmospheric conditions to understand the impact on Midwestern crops. These findings are especially remarkable because the crops in this SoyFACE experiment were exposed to the same environmental conditions (i.e. the sun, wind, rain, clouds, etc.) as other Illinois field crops."It's actually a bit of a surprise," Bernacchi said. "I've been doing field research for quite some time, and variability is one of the things that's an inherent part of field research. Of course, we did see variability in yields from year to year, but the difference between the modified and unmodified plants was remarkably consistent over these three years."These modified soybeans are just one part of the equation to meet the demands of 2050. This modification can likely be combined with other modifications -- a process called "stacking" -- to further improve yields. "When we're trying to meet our food needs for the future, this specific modification is one of the many tools that we're going to need to rely upon," Bernacchi said. "There is a lot of research across the planet that's looking at different strategies to make improvements, and many of these are not mutually exclusive." | Genetically Modified | 2,017 |
May 3, 2017 | https://www.sciencedaily.com/releases/2017/05/170503131927.htm | Spotted skunk evolution driven by climate change, suggest researchers | Climate plays a key role in determining what animals can live where. And while human-induced climate change has been causing major problems for wildlife as of late, changes in Earth's climate have impacted evolution for millions of years -- offering tantalizing clues into how to protect animals facing climate change today. In a new paper in | "By analyzing western spotted skunk DNA, we learned that Ice Age climate change played a crucial role in their evolution," says lead author Adam Ferguson, Collections Manager of Mammals at The Field Museum in Chicago and affiliate of Texas Tech University. "Over the past million years, changing climates isolated groups of spotted skunks in regions with suitable abiotic conditions, giving rise to genetic sub-divisions that we still see today."Western spotted skunks are really stinkin' cute -- at two pounds, they're smaller than the striped Pepe Le Pew variety, their coats are an almost maze-like pattern of black and white swirls, and when they spray, they often do a hand-stand, hind legs and fluffy tail in the air as they unleash smelly chemicals to ward off predators. They're found throughout the Western US and Mexico, in a wide variety of climates -- they thrive everywhere from Oregon's temperate rainforests to the Sonoran, the hottest desert in Mexico.There are three genetic sub-groups, called clades, of western spotted skunks. Often, clades develop when a species is split up by geography. If a species is separated by, say, a mountain range, the groups on either side of the mountain may wind up splitting off from each other genetically. However, the division of the skunks into three clades doesn't seem to have been driven solely by geographical barriers -- populations separated by mountains are more or less genetically identical. Instead, the skunks vary genetically from one historic climate region to another, due to Ice Age climate change."Western spotted skunks have been around for a million years, since the Pleistocene Ice Age," explains Ferguson. "During the Ice Age, western North America was mostly covered by glaciers, and there were patches of suitable climates for the skunks separated by patches of unsuitable climates. These regions are called climate refugia. When we analyzed the DNA of spotted skunks living today, we found three groups that correspond to three different climate refugia.""That means that for spotted skunk evolution, climate change appears to have been a more important factor than geographical barriers," says Ferguson.In the study, scientists used DNA samples from 97 skunks from a variety of regions and climates in the American Southwest. Upon sequencing the DNA, the scientists were surprised to see that the skunks split into three clades based on pockets of suitable climate present during the Pleistocene."Small carnivores like skunks haven't been well-studied when it comes to historical climate change," says Ferguson. "We know how small mammals like rodents respond to changing climates, and we know how bigger carnivores like wolves respond, but this study helps bridge the gap between them."Ferguson also notes that skunks don't deserve the bad rap they get. "Skunks are a really interesting family of North American carnivores -- they're well-known, but not well-studied. And studying them comes with a cost -- they stink, even their tissues stink, and you run the risk of getting sprayed. But they're important to their ecosystems -- for example, they eat insects and rodents that damage our crops," he says.Moreover, Ferguson says, the study can illuminate the bigger picture of biodiversity in the face of climate change -- an issue that grows increasingly relevant as human-driven climate change affects more and more of the world's animals."What we know about the past can inform what we expect to see in the future," says Ferguson. "Understanding these genetic subdivisions that happened as a result of changing climatic conditions can help us conserve skunks and other animals in the future."Before working at The Field Museum, Adam Ferguson was affiliated with Texas Tech University and completed this research there. Ferguson's co-authors are affiliated with Angelo State University, the National Museum of Natural History, the National Zoological Park, the US Fish and Wildlife Service, and the University of New Mexico. | Genetically Modified | 2,017 |
May 1, 2017 | https://www.sciencedaily.com/releases/2017/05/170501112514.htm | Gene editing strategy eliminates HIV-1 infection in live animals | A permanent cure for HIV infection remains elusive due to the virus's ability to hide away in latent reservoirs. But now, in new research published in print May 3 in the journal | The team is the first to demonstrate that HIV-1 replication can be completely shut down and the virus eliminated from infected cells in animals with a powerful gene editing technology known as CRISPR/Cas9. The work was led by Wenhui Hu, MD, PhD, currently Associate Professor in the Center for Metabolic Disease Research and the Department of Pathology (previously in the Department of Neuroscience) at LKSOM; Kamel Khalili, PhD, Laura H. Carnell Professor and Chair of the Department of Neuroscience, Director of the Center for Neurovirology, and Director of the Comprehensive NeuroAIDS Center at LKSOM; and Won-Bin Young, PhD. Dr. Young was Assistant Professor in the Department of Radiology at the University of Pittsburgh School of Medicine at the time of the research. Dr. Young recently joined LKSOM.The new work builds on a previous proof-of-concept study that the team published in 2016, in which they used transgenic rat and mouse models with HIV-1 DNA incorporated into the genome of every tissue of the animals' bodies. They demonstrated that their strategy could delete the targeted fragments of HIV-1 from the genome in most tissues in the experimental animals."Our new study is more comprehensive," Dr. Hu said. "We confirmed the data from our previous work and have improved the efficiency of our gene editing strategy. We also show that the strategy is effective in two additional mouse models, one representing acute infection in mouse cells and the other representing chronic, or latent, infection in human cells."In the new study, the team genetically inactivated HIV-1 in transgenic mice, reducing the RNA expression of viral genes by roughly 60 to 95 percent, confirming their earlier findings. They then tested their system in mice acutely infected with EcoHIV, the mouse equivalent of human HIV-1."During acute infection, HIV actively replicates," Dr. Khalili explained. "With EcoHIV mice, we were able to investigate the ability of the CRISPR/Cas9 strategy to block viral replication and potentially prevent systemic infection." The excision efficiency of their strategy reached 96 percent in EcoHIV mice, providing the first evidence for HIV-1 eradication by prophylactic treatment with a CRISPR/Cas9 system.In the third animal model, latent HIV-1 infection was recapitulated in humanized mice engrafted with human immune cells, including T cells, followed by HIV-1 infection. "These animals carry latent HIV in the genomes of human T cells, where the virus can escape detection," Dr. Hu explained. Following a single treatment with CRISPR/Cas9, viral fragments were successfully excised from latently infected human cells embedded in mouse tissues and organs.In all three animal models, the researchers utilized a recombinant adeno-associated viral (rAAV) vector delivery system based on a subtype known as AAV-DJ/8. "The AAV-DJ/8 subtype combines multiple serotypes, giving us a broader range of cell targets for the delivery of our CRISPR/Cas9 system," Dr. Hu said. They also re-engineered their previous gene editing apparatus to now carry a set of four guide RNAs, all designed to efficiently excise integrated HIV-1 DNA from the host cell genome and avoid potential HIV-1 mutational escape.To determine the success of the strategy, the team measured levels of HIV-1 RNA and used a novel live bioluminescence imaging system. "The imaging system, developed by Dr. Young while at the University of Pittsburgh, pinpoints the spatial and temporal location of HIV-1-infected cells in the body, allowing us to observe HIV-1 replication in real-time and to essentially see HIV-1 reservoirs in latently infected cells and tissues," Dr. Khalili explained.The new study marks another major step forward in the pursuit of a permanent cure for HIV infection. "The next stage would be to repeat the study in primates, a more suitable animal model where HIV infection induces disease, in order to further demonstrate elimination of HIV-1 DNA in latently infected T cells and other sanctuary sites for HIV-1, including brain cells," Dr. Khalili said. "Our eventual goal is a clinical trial in human patients." | Genetically Modified | 2,017 |
April 27, 2017 | https://www.sciencedaily.com/releases/2017/04/170427111206.htm | We are more than our DNA: Discovering a new mechanism of epigenetic inheritance | Giacomo Cavalli's team at the Institute of Human Genetics (University of Montpellier / CNRS), in collaboration with the French National Institute for Agricultural Research (INRA), has demonstrated the existence of transgenerational epigenetic inheritance (TEI) among Drosophila fruit flies. By temporarily modifying the function of Polycomb Group (PcG) proteins -- which play an essential role in development -- the researchers obtained fruit fly lines having the same DNA sequence but different eye colors. An example of epigenetic inheritance, this color diversity reflects varying degrees of heritable, but reversible, gene repression by PcG proteins. It is observed in both transgenic and wild-type lines and can be modified by environmental conditions such as ambient temperature. The scientists' work is published in | Same DNA, different color. Researchers have obtained drosophila epilines -- that is, genetically identical lineages with distinct epigenetic characteristics -- with white, yellow, and red eyes respectively. They achieved this by transiently disturbing interactions between target genes and PcG proteins, which are complexes involved in the repression of several genes governing development. Cavalli and his team at the Institute of Human Genetics (University of Montpellier / CNRS) are the first to show that regulation of gene position can lead to transgenerational inheritance.DNA is not the only medium for communicating information necessary for cell function. Cell processes are also determined by the chemical labeling (or marks) and specific spatial organization of our genomes, which are epigenetic characteristics -- that is, nongenetic but nonetheless inheritable traits. Epigenetic marks include modifications of histones, the proteins around which DNA is wound. PcG proteins, on the other hand, play a regulatory role by affecting 3D chromosomal configuration, which establishes certain interactions between genes in the cell nucleus. The position of a gene at any given moment determines whether it is active or repressed.Through temporary disruption of these interactions, the scientists were able to produce Drosophila epilines characterized by different levels of PcG-dependent gene repression or activation. They verified that these epilines were indeed isogenic, or genetically identical, by sequencing the genome of each. Despite their identical DNA, the integrity of epilines -- and the unique phenotypic characteristics they program -- can be maintained across generations. But this phenomenon is reversible. Crosses between drosophilas with over- or underexpressed genes and others having no such modifications to gene activity "reset" eye color without altering the DNA sequence, thus demonstrating the epigenetic nature of this inheritance.The researchers then showed that new environmental conditions, such as a different ambient temperature, can affect the expression of epigenetic information over several generations, but they do not erase this information. Such transient effects of environmental factors to which earlier generations were exposed on the expression of characteristics in their progeny illustrate the unique, pliable nature of this epigenetic mechanism. By conducting "microcosm" experiments that recreated natural environmental conditions, the researchers -- working with INRA -- confirmed that epigenetic inheritance in Drosophila can be maintained in the wild.Giacomo Cavalli's crew has therefore proven the existence of Polycomb-mediated stable transgenerational epigenetic inheritance dependent on 3D chromosomal structure. Their findings offer new horizons for biomedical science. They suggest that epigenetics could partly solve the mystery of "missing heritability" -- that is, the absence of any apparent link between genetic makeup and certain normal hereditary traits and diseases. | Genetically Modified | 2,017 |
April 24, 2017 | https://www.sciencedaily.com/releases/2017/04/170424141347.htm | Nanosponges lessen severity of streptococcal infections | In a new study, researchers show that engineered nanosponges that are encapsulated in the membranes of red blood cells can reduce the severity of infections caused by group A | Tamara Escajadillo, graduate student researcher at the University of California in San Diego, will present the new study at the American Society for Pharmacology and Experimental Therapeutics annual meeting during the Experimental Biology 2017 meeting, to be held April 22-26 in Chicago.One reason group A "Our engineered nanosponges capture and inactivate the toxins produced by bacteria, thus reducing damage to cells," said Escajadillo. "By demonstrating their effectiveness with live Streptococcal infections, we provide compelling evidence for the potential functionality of the nanosponges in a clinical setting."The researchers created the nanosponges by separating the membranes of human red blood cells from their internal contents and stabilizing the membranes with an engineered core designed to absorb the toxins produced by pathogenic bacteria. Experiments with cultured cells showed that in the presence of group A "The use of human cellular membranes as a decoy has the potential to block a large family of related microbial toxins and reduce the severity of invasive bacterial infections in vulnerable patients," said Escajadillo.The researchers are now testing their nanosponges with a variety of important bacterial toxins and live infections. They also want to develop a version that could counteract the dangerous inflammatory cascade that occurs in bacterial sepsis, a life-threatening condition that arises when the body is overwhelmed with an infection. | Genetically Modified | 2,017 |
April 24, 2017 | https://www.sciencedaily.com/releases/2017/04/170424141205.htm | Does the microbiome play a role in the effectiveness of colorectal cancer treatment? | The bacteria residing in your digestive tract, or your gut microbiota, may play an important role in your ability to respond to chemotherapy drugs in the clinic, according to a new study by scientists at the University of Massachusetts Medical School. Published in | Cancer doctors have long been puzzled by how dramatically different two patients with the same disease can respond to the same treatment -- even in cases where twins, who are genetically identical, have the same diagnosis. "Two twins, genetically identical, who have colorectal cancer could potentially respond very differently to the same treatment because of their microbiome," said Dr. Walhout, PhD, the Maroun Semaan Chair in Biomedical Research, co-director of the Program in Systems Biology and professor of molecular medicine at UMMS. "If we can learn how bacteria affect the efficacy or toxicity of chemotherapies, it's not hard to imagine developing personalized medicine built on probiotics that could improve the clinical benefits of some cancer treatments."Walhout and colleagues used the humble model organism Worms fed a diet of To produce this effect, the bacteria needed to be alive in order to actively metabolize the drug or to produce a metabolite when exposed to FUDR. "Because these are bacteria already in your microbiome," said Aurian Garcia Gonzalez, a MD/PhD candidate in the Walhout lab, "any pill or treatment you take orally would be exposed to the bacteria and the efficacy of the drug may be modulated by different bacteria."Genetic screens were then used to determine which bacterial genes are responsible for increasing or decreasing drug efficiency in "This isn't a model that indisputably demonstrates a therapeutic finding but the implications are quite interesting nonetheless," said Walhout. "Using the humble worm and powerful genetic tools, we can potentially use probiotics to develop a personalized medicine that might maximize the benefit of some chemotherapy treatments."Any bacteria that can be fed to a worm can be tested and any drug that has an observed phenotype can be tested," explained Walhout. "This gives scientists a huge space to test because of the thousands of combinations of drugs and bacteria that could conceivably be tested. "We hope this study inspires more people to look at this space, and explore the use of our findings to clinical settings in the future." | Genetically Modified | 2,017 |
April 20, 2017 | https://www.sciencedaily.com/releases/2017/04/170420141852.htm | New tools visualize where bacterial species live in the gut, control their activity | Gut microbes play wide-ranging roles in health and disease, but there has been a lack of tools to probe the relationship between microbial activity and host physiology. Two independent studies in mice published April 20 in the journal | "We found that tools from synthetic biology can allow us to ask new questions about the gut microbiota," says Andrew Goodman of Yale University School of Medicine, senior author of one of the studies. "We also imagine these strategies may provide a starting point for on-demand delivery of therapeutics or other molecules from the microbiota."Advances in sequencing technology have enabled in-depth characterization of bacterial species found in the gut, but tools to manipulate the gut microbiome have lagged far behind. Although tools have been developed for model organisms such as Escherichia coli, these systems do not work in In one of the studies, Justin Sonnenburg of the Stanford University School of Medicine and his team developed a way to engineer Using this panel of promoters, the researchers genetically engineered six different In a separate experiment, Sonnenburg and his team genetically engineered two In future research, Sonnenburg and his team will continue to develop these tools to engineer bacteria to produce proteins at a precise time or location. "On the commercial side, the expression tools may allow us to deliver therapeutic proteins to the gut by producing them in the microbes that live inside of us," says Weston Whitaker, lead author of the Stanford study. "The use of bacterial cells for drug delivery opens the door to smart therapeutics that are produced at the right time and location."In the other study, Yale's Andrew Goodman and his team also developed a panel of synthetic promoters enabling the fine-tuned control of gene activity in diverse In the OFF state, gene activity controlled by the synthetic promoters was completely shut off, but in the presence of anhydrotetracycline, gene activity rapidly increased by a factor of 9,000. The researchers next introduced the engineered bacteria into mice and confirmed that their tools allow gene activity in gut bacteria to be tightly controlled, simply by adding different amounts of anhydrotetracycline to the drinking water of mice.If extended to humans, this approach could potentially enable on-demand delivery of therapeutic compounds. Moreover, precise control of bacterial gene activity in specific locations in the gastrointestinal tract could be achieved by administering anhydrotetracycline through different routes, for example, via time- or pH-dependent delayed release capsules or surgically through catheterization. In future studies, Goodman and his team will apply their system to other microbes and other types of interactions between gut microbes and their hosts."These tools open the door to new types of studies to better understand our microbiota and to define how gut commensal bacteria can be engineered for therapeutic purposes," Sonnenburg says. "However, before gut commensals can be engineered for therapeutics, it will be important to develop methods of safely and reliably colonizing the human gut, which will require more research." | Genetically Modified | 2,017 |
April 20, 2017 | https://www.sciencedaily.com/releases/2017/04/170420141822.htm | Discovering the basics of 'active touch' | Working with genetically engineered mice -- and especially their whiskers -- Johns Hopkins researchers report they have identified a group of nerve cells in the skin responsible for what they call "active touch," a combination of motion and sensory feeling needed to navigate the external world. The discovery of this basic sensory mechanism, described online April 20 in the journal | Study leader Daniel O'Connor, Ph.D., assistant professor of neuroscience at the Johns Hopkins University School of Medicine, explains that over the past several decades, researchers have amassed a wealth of knowledge about the sense of touch. "You can open up textbooks and read all about the different types of sensors or receptor cells in the skin," he says. "However, almost everything we know is from experiments where tactile stimulation was applied to the stationary skin -- in other words, passive touch."Such "passive touch," O'Connor adds, isn't how humans and other animals normally explore their world. For example, he says, people entering a dark room might search for a light switch by actively feeling the wall with their hands. To tell if an object is hard or soft, they'd probably need to press it with their fingers. To see if an object is smooth or rough, they'd scan their fingers back and forth across an object's surface.Each of these forms of touch combined with motion, he says, is an active way of exploring the world, rather than waiting to have a touch stimulus presented. They each also require the ability to sense a body part's relative position in space, an ability known as proprioception.While some research has suggested that the same populations of nerve cells, or neurons, might be responsible for sensing both proprioception and touch necessary for this sensory-motor integration, whether this was true and which neurons accomplish this feat have been largely unknown, O'Connor says.To find out more, O'Connor and his team developed an experimental system with mice that allowed them to record electrical signals from specific neurons located in the skin, during both touch and motion.The researchers accomplished this, they report, by working with members of a laboratory led by David Ginty, Ph.D., a former Johns Hopkins University faculty member, now at Harvard Medical School, to develop genetically altered mice. In these animals, a type of sensory neuron in the skin called Merkel afferents were mutated so that they responded to touch -- their "native" stimulus, and one long documented in previous research -- but also to blue light, which skin nerve cells don't normally respond to.The scientists trained the rodents to run on a mouse-sized treadmill that had a small pole attached to the front that was motorized to move to different locations. Before the mice started running, the researchers used their touch-and-light sensitized system to find a single Merkel afferent near each animal's whiskers and used an electrode to measure the electrical signals from this neuron.Much like humans use their hands to explore the world through touch, mice use their whiskers, explains O'Connor. Consequently, as the animals began running on the treadmill, they moved their whiskers back and forth in a motion that researchers call "exploratory whisking."Using a high-speed camera focused on the animals' whiskers, the researchers took nearly 55,000,000 frames of video while the mice ran and whisked. They then used computer-learning algorithms to separate the movements into three different categories: when the rodents weren't whisking or in contact with the pole; when they were whisking with no contact; or when they were whisking against the pole.They then connected each of these movements -- using video snapshots captured 500 times every second -- to the electrical signals coming from the animals' blue-light-sensitive Merkel afferents.The results show that the Merkel afferents produced action potentials -- the electrical spikes that neurons use to communicate with each other and the brain -- when their associated whiskers contacted the pole. That finding wasn't particularly surprising, O'Connor says, because of these neurons' well-established role in touch.However, he says, the Merkel afferents also responded robustly when they were moving in the air without touching the pole. By delving into the specific electrical signals, the researchers discovered that the action potentials precisely related to a whisker's position in space. These findings suggest that Merkel afferents play a dual role in touch and proprioception, and in the sensory-motor integration necessary for active touch, O'Connor says.Although these findings are particular to mouse whiskers, he cautions, he and his colleagues believe that Merkel afferents in humans could serve a similar function, because many anatomical and physiological properties of Merkel afferents appear similar across a range of species, including mice and humans.Besides shedding light on a basic biological question, O'Connor says, his team's research could also eventually improve artificial limbs and digits. Some prosthetics are now able to interface with the human brain, allowing users to move them using directed brain signals. While this motion is a huge advance beyond traditional static prosthetics, it still doesn't allow the smooth movement of natural limbs. By integrating signals similar to those produced by Merkel afferents, he explains, researchers might eventually be able to create prosthetics that can send signals about touch and proprioception to the brain, allowing movements akin to native limbs. | Genetically Modified | 2,017 |
April 20, 2017 | https://www.sciencedaily.com/releases/2017/04/170420090211.htm | 'Eating with the eyes' is hard-wired in the brain | Have you ever wondered why just seeing food can make your mouth start to water? By visualizing neuronal activity in specific areas of the zebrafish brain, scientists at the National Institute of Genetics (NIG) in Japan have revealed a direct link between visual perception of food and feeding motivation. The study, published in the April 20, 2017 issue of | "In vertebrate animals, feeding behavior is regulated by a brain area called the hypothalamus. The hypothalamic feeding center integrates information about bodily energy requirements and environmental food availability. Zebrafish, like humans, mostly use vision for recognition of food or prey. It was not known how the hypothalamus receives visual information about prey. We first demonstrated that neurons in the hypothalamus do indeed respond to the sight of prey. Then we looked for neurons in the visual system that responded to prey and discovered 'prey detector' neurons in an area called the pretectum. Furthermore, we found a direct neural link connecting the prey detector neurons to the hypothalamic feeding center," Dr. Muto, the leading author of the study, explained.The key to this discovery has been recent progress in the development and improvement of the highly sensitive, genetically encoded calcium indicator GCaMP, which can be used to monitor neuronal activity in the form of calcium signals. Another important technology is the ability to control the specific neurons in which GCaMP is expressed. This was critical for recording distinct calcium signals from identifiable neurons.Prof. Kawakami, the senior author, showed us his zebrafish facility where thousands of fish tanks can be seen, each of which contains genetically different fish that can turn on, or drive the GCaMP expression in different types of cells in the brain or in the body. This collection of driver fish lines is being used to study various tissues and cell types by zebrafish researchers all over the world. Of the nearly 2,000 such driver fish lines in the lab, two played important roles in the current study: one for the imaging of the prey detector neurons, and the other for the feeding center in the hypothalamus."Successful brain imaging was made possible through development of our genetic resources on which I have spent more than twenty years. This is the power of zebrafish genetics. This work showcases a successful application of our genetic resources in the study of brain function," Prof. Kawakami said."Our study demonstrates how tightly visual perception of food is linked to motivational feeding behavior in vertebrate animals. This is an important step toward understanding how feeding is regulated and can be modulated in normal conditions as well as in feeding disorders," Dr. Muto said. | Genetically Modified | 2,017 |
April 10, 2017 | https://www.sciencedaily.com/releases/2017/04/170410095616.htm | New tool can help estimate genetically modified pollen spread | Food purists may have cause to celebrate thanks to a recent international study directed by the University of British Columbia. The study, which evaluated the spread of genetically modified (GM) organisms to non-modified crops, has implications from farm to family. | "Trying to figure out how far GM pollen will travel is really difficult," says study co-author Rebecca Tyson, associate professor of mathematics at UBC Okanagan."It is important to have accurate tools to estimate this, so that unintentional cross-pollination of GM material to non-GM crops can be minimized."According to stastista.com, genetically modified crops in Canada are mostly located in Ontario and Quebec and consist of canola, soybeans, corn and sugar beets. More than 90 per cent of the canola grown in Canada is genetically modified.Tyson suggests that the simplest way to minimize cross fertilization between crops is to separate them. Up until now, the isolation distances have been somewhat haphazardly determined. Previous estimates have been based on two standard models, which either overestimate or underestimate pollen movement. The gap between these two distances makes prediction difficult and thus necessitates improved calculations, she explains.Tyson's research offers a new analytical tool which can provide a much improved estimate of how far pollen will travel.Along with colleagues from the Université catholique de Louvain (Belgium) and Delft University (The Netherlands), she developed a mathematical model of pollen dispersal by bees, based on field experiments."Our results suggest that separation distances of several hundred metres, proposed by some European countries, is unnecessarily large but separation by 40 metres is not sufficient," says Tyson. "Using our model, we can calculate and suggest separation sizes with better accuracy. For example, we have estimated that for a 0.9 per cent cross-pollination rate, the ideal distance of separation between two crops is between 51 and 88 metres, depending on crop size and type."These numbers are specific to particular crops and landscapes, she explains, but the predictive ability is the same."We believe that our model provides a more accurate assessment of GM pollen cross-pollination than previous models," adds Tyson. "We are hopeful these findings will simplify the decision-making process for crop-growers and policy makers." | Genetically Modified | 2,017 |
April 6, 2017 | https://www.sciencedaily.com/releases/2017/04/170406121549.htm | Synthetic biologists engineer inflammation-sensing gut bacteria | Synthetic biologists at Rice University have engineered gut bacteria capable of sensing colitis, an inflammation of the colon, in mice. The research points the way to new experiments for studying how gut bacteria and human hosts interact at a molecular level and could eventually lead to orally ingestible bacteria for monitoring gut health and disease. | The research, published in a new study in "The gut harbors trillions of microorganisms that play key roles in health and disease," Tabor said. "However, it is a dark and relatively inaccessible place, and few technologies have been developed to study these processes in detail. On the other hand, bacteria have evolved tens of thousands of genetically encoded sensors, many of which sense gut-linked molecules. Thus, genetically engineered sensor bacteria have tremendous potential for studying gut pathways and diagnosing gut diseases."Synthetic biologists like Tabor specialize in programming single-celled organisms like bacteria in much the same way an engineer might program a robot. In particular, Tabor's team is working to develop bacterial sensors that can detect disease signals in the gut. Like electrical engineers who build circuits from wires and electronic components, Tabor's team uses genetic circuits to program single-celled creatures to carry out complex information processing.Previous work has suggested that alterations to the gut microbiota, genetic predisposition and other environmental factors may play key roles in inflammatory bowel disease, a condition that includes Crohn's disease and ulcerative colitis and which affects as many as 1.6 million Americans."Based on a number of previous studies, we hypothesized that the molecule thiosulfate may be elevated during colitis," Daeffler said. "It has been difficult for scientists to study this link because there aren't tools for reliably measuring thiosulfate in living animals. Our first goal in this project was to engineer such a tool."From the outset of the project in 2015, Daeffler said, the idea was to use sensor bacteria, in this case an engineered form of "There's a link between gut sulfur metabolism and inflammation, and we knew that we needed to be able to measure sulfur metabolites accurately to diagnose colon inflammation," she said.Tabor said study co-author Ravi Sheth, an undergraduate researcher in the group in 2015, used a computer program to identify potential sensors of thiosulfate and other sulfur compounds in the genome of Daeffler spent one year engineering The researchers administered orally two drops containing about a billion sensor bacteria to both healthy mice and to mice with colitis. They measured the activity of the sensor bacteria in each group six hours later. The tell-tale green fluorescent protein showed up in the feces of the mice. Though it was not visible to the unaided eye, it could easily be measured with a standard laboratory instrument called a flow cytometer.The team found that the thiosulfate sensor was activated in the mice with inflammation, and was not activated in the healthy mice. Furthermore, the researchers found that the more inflammation the mouse had, the more the sensor was activated.Tabor said the study shows that gut bacteria can be outfitted with engineered sensors and used to noninvasively measure specific metabolites and that this result could open the door to many new studies that could help elucidate a wide range of gut processes.Though it would likely take several additional years of development, and it remains unknown if thiosulfate is a biomarker of human colitis, the sensor bacteria might eventually be re-engineered to function as a diagnostic of human colitis, Tabor said. In particular, the green fluorescent protein could be replaced with an enzyme that makes a colored pigment."We'd like to develop a home inflammation test where a person prone to colitis flare-ups would eat yogurt that contained the engineered bacteria and see blue pigment in the toilet if they were sick," he said.Tabor said such a test could reduce unneeded and costly trips to the doctor and unneeded colonoscopy procedures, which are both expensive and invasive. He said his team has begun collaborations with gastroenterologists at Baylor to achieve this goal. | Genetically Modified | 2,017 |
April 5, 2017 | https://www.sciencedaily.com/releases/2017/04/170405131009.htm | The redomestication of wolves | On landscapes around the world, environmental change is bringing people and large carnivores together -- but the union is not without its problems. Human-wildlife conflict is on the rise as development continues unabated and apex predators begin to reoccupy their former ranges. Further complicating matters, many of these species are now reliant on anthropogenic, or human, foods, including livestock, livestock and other ungulate carcasses, and garbage. | Writing in Other instances of these phenomena abound. In a similar case in Australia, dingoes gained access to anthropogenic foods from a waste facility. The result, according to the authors, was "decreased home-range areas and movements, larger group sizes, and altered dietary preferences to the extent that they filled a similar dietary niche to domestic dogs." Moreover, wrote the authors, "the population of subsidized dingoes was a genetically distinct cluster," which may portend future speciation events. Hybridization among similar predator species may also contribute to evolutionary divergence: "Anthropogenic resources in human-modified environments could increase the probability of non-aggressive contact" between species. According to the authors, "If extant wolves continue to increase their reliance on anthropogenic foods, we should expect to observe evidence of dietary niche differentiation and, over time, the development of genetic structure that could signal incipient speciation."Wolves' use of anthropogenic food could have serious implications for wider conservation efforts, as well. In particular, Newsome and his colleagues raise concerns about whether wolf reintroduction and recolonisation programs will meet ecosystem-restoration goals in human-modified systems. Managers will need to consider "how broadly insights into the role played by wolves gleaned from protected areas such as Yellowstone can be applied in areas that have been greatly modified by humans," say the authors.Newsome and his colleagues call for further research -- in particular, "studies showing the niche characteristics and population structure of wolves in areas where human influence is pervasive and heavy reliance on human foods has been documented." Through such studies, they argue that "we might be able to ask whether heavy reliance of anthropogenic subsidies can act as a driver of evolutionary divergence and, potentially, provide the makings of a new dog." | Genetically Modified | 2,017 |
April 5, 2017 | https://www.sciencedaily.com/releases/2017/04/170405101940.htm | Fish eyes to help understand human inherited blindness | Newborns babies can be at risk of congenital blindness, presenting sight defects due to lesions or to genetic mutations in their genome. Among the latter, Leber Congenital Amaurosis -- or LCA -- is one of the most widespread causes of child blindness and accounts for nearly 5% of vision impairments overall. The syndrome can be genetically transmitted to a child when both parents possess at least one dysfunctional copy of a gene involved in eye development. However, the molecular mechanism behind the disease remains unclear. Now OIST researchers in the Developmental Neurobiology Unit have exposed a similar syndrome in zebrafish, which are an excellent model for studying human diseases. From this research published in | LCA affect the retina, the thin layer of tissue at the back of the eye that detects light as well as differentiates colors and communicates the information to the brain via the optic nerve. A healthy retina usually features light-sensitive cells -- photoreceptors -- called cones and rods. Cones are specialized in bright environment and detect colors while rods are used in dim light but are monochrome, which is why we see in black and white at night. A person with LCA will display deformed or absent cones and rods, thus preventing the detection of light. A total of 24 genes including a gene called Aipl1 -- standing for aryl hydrocarbon receptor interacting protein like 1 -- have been linked to LCA in humans and mice. The illness occurs when a DNA mutation within one of the genes affects the normal ocular development or induces photoreceptor -- the cones and rods -- degeneration.OIST scientists selected the zebrafish as an animal model because its retina is rich in cones and its visual acuity can be measured with a simple device. The researchers studied a genetically mutated zebrafish embryo that did not react to visual stimuli. They discovered that zebrafish DNA contains two Aipl1 genes, namely Aipl1a and Aipl1b, which are respectively active in rods and cones. The mutant -- called gold rush (gosh) -- presents a genetic mutation in the Aipl1b DNA sequence, losing Aipl1 activity in cone photoreceptors. Consequently, the cone photoreceptors showed a deformed morphology and sustained degeneration. Rods however were not affected, suggesting the degeneration is cone-specific.Probing further, the authors of the study also revealed that Aipl1 is critical for the stability of two enzymes -- the cGMP-phosphodiesterase 6 and the guanylate cyclase -- which mediate phototransduction, the process of converting light into an electrical signal. Without these enzymes, the zebrafish is unable to react to light stimulus as the information is stopped in photoreceptors and fails to initiate the transmission of visual information into the brain through the optic nerve.The research indicates that Aipl1b gene is important for visual functions and maintenance of cone photoreceptors in the zebrafish. Without it, cones do not detect light stimuli and degenerate during development, which are clues for treating the illness in humans. Dr. Maria Iribarne, first author of this study, commented: "The gosh mutant is a good model for understanding the molecular and cellular mechanism of cone cell death and the pathological process of human LCA. Hopefully, this new knowledge will help to find a future cure for patients who suffer such a devastating disease as LCA." | Genetically Modified | 2,017 |
April 4, 2017 | https://www.sciencedaily.com/releases/2017/04/170404160055.htm | Scientists engineer sugarcane to produce biodiesel, more sugar for ethanol | A multi-institutional team led by the University of Illinois have proven sugarcane can be genetically engineered to produce oil in its leaves and stems for biodiesel production. Surprisingly, the modified sugarcane plants also produced more sugar, which could be used for ethanol production. | The dual-purpose bioenergy crops are predicted to be more than five times more profitable per acre than soybeans and two times more profitable than corn. More importantly, sugarcane can be grown on marginal land in the Gulf Coast region that does not support good corn or soybean yields."Instead of fields of oil pumps, we envision fields of green plants sustainably producing biofuel in perpetuity on our nation's soil, particularly marginal soil that is not well suited to food production," said Stephen Long, Gutgsell Endowed Professor of Plant Biology and Crop Sciences. Long leads the research project Plants Engineered to Replace Oil in Sugarcane and Sweet Sorghum (PETROSS) that has pioneered this work at the Carl R. Woese Institute for Genomic Biology at Illinois."While fuel prices may be considered low today, we can remember paying more than $4 per gallon not long ago," Long said. "As it can take 10-15 years for this technology to reach farmers' fields, we need to develop these solutions to ensure our fuel security today and as long as we need liquid fuels into the future."Published in They recovered 0.5 and 0.8 percent oil from two of the modified sugarcane lines, which is 67% and 167% more oil than unmodified sugarcane, respectively. "The oil composition is comparable to that obtained from other feedstocks like seaweed or algae that are being engineered to produce oil," said co-author Vijay Singh, Director of the Integrated Bioprocessing Research Laboratory at Illinois."We expected that as oil production increased, sugar production would decrease, based on our computer models," Long said. "However, we found that the plant can produce more oil without loss of sugar production, which means our plants may ultimately be even more productive than we originally anticipated."To date, PETROSS has engineered sugarcane with 13 percent oil, 8 percent of which is the oil that can be converted into biodiesel. According to the project's economic analyses, plants with just 5 percent oil would produce an extra 123 gallons of biodiesel per acre than soybeans and 350 more gallons of ethanol per acre than corn. | Genetically Modified | 2,017 |
April 4, 2017 | https://www.sciencedaily.com/releases/2017/04/170404084436.htm | New rice fights off drought | Scientists at the RIKEN Center for Sustainable Resource Science (CSRS) have developed strains of rice that are resistant to drought in real-world situations. Published in | As the amount of rice needed to help feed the global population increases, the consequences of drought-related crop reduction are becoming more severe. RIKEN scientists and their collaborators tackled this issue by developing transgenic strains of rice that are more resistant to drought.Normally, plants adapt to drought-related stress by producing osmoprotectants -- molecules like soluble sugars that help prevent water from leaving cells. Galactinol synthase (GolS) is an enzyme needed to produce one these important sugars called galactinol. In previous work, RIKEN scientists showed that "The For this study, they created several lines of transgenic Brazilian and African rice that overexpress this gene, and with their CIAT and JIRCAS collaborators, tested how well the rice grew in different conditions in different years.The results were very promising. First, they grew the different rice lines in greenhouse conditions and showed that the modified Brazilian and African rice did indeed show higher levels of galactinol than the unmodified control rice. Next, they tested tolerance to drought during the seedling growth period because this period often overlaps with seasonal drought. In order to precisely control this part of the experiment, it was conducted in a rainout shelter that allowed them to artificially create drought-like conditions. After three weeks, the modified strains had grown taller and showed less leaf-rolling, a common response to drought stress.Drought tolerance was next confirmed at the reproductive stage in three rainout field trials in Colombia. These trials were during different seasons and different locations. Nevertheless, transgenic lines in both species of rice showed higher yield, greater biomass, lower leaf-rolling, and greater fertility than the unmodified rice. Closer examination showed that five of the most promising strains had greater relative water content during drought conditions, and also used more light for photosynthesis, and contained more chlorophyll.Finally, they tested the transgenic rice over a three-year period in different natural environments. Again, several of the transgenic strains showed higher grain yield under mild and severe natural drought.When might we see this useful rice on the market? According to Takahashi, the greatest barrier to commercial availability is that they used genetically modified (GM) technology to generate the | Genetically Modified | 2,017 |
April 3, 2017 | https://www.sciencedaily.com/releases/2017/04/170403123328.htm | Ways to encourage 'refuge' planting, slow resistance to Bt crops | A new study from North Carolina State University finds a significant shortfall in the amount of "refuge" cropland being planted in North Carolina -- likely increasing the rate at which crop pests will evolve the ability to safely devour genetically engineered Bt crops. However, the study also identified actions that may make farmers more likely to plant refuge crops in the future. | For about 20 years, growers have made use of Bt crops to limit crop damage from pests. Bt crops, including corn, are genetically engineered to produce proteins from the Bacillus thuringiensis (Bt) bacterium. These proteins are harmless to vertebrates, but toxic to a specific class of invertebrate crop pests.To date, these Bt crops have been remarkably successful. However, insect pests have shown the ability to evolve resistance to Bt proteins. In order to slow down the development of Bt resistance, farmers who plant Bt crops are urged to plant a certain percentage of their fields with non-Bt crops -- called refuge crops. In fact, in the case of Bt corn, farmers are required to plant a section of their fields with refuge crops.That's because refuge crops provide fodder for insect pests that are not resistant to Bt proteins. These pests are then able to breed with their Bt-resistant counterparts, diluting Bt resistance in the overall pest population.But compliance with planting refuge crops is variable. Some growers plant too little of their fields with Bt crops, and some don't plant refuge crops at all.This raised some interesting questions for Dominic Reisig, an associate professor of entomology at NC State and an extension specialist at the Vernon James Research & Extension Center in eastern North Carolina. Reisig divides his time between conducting research and helping farmers deal with problems related to insect crop pests. Recently, Reisig began to wonder: How many growers aren't planting sufficient refuge crops? Do growers understand the rationale behind refuge crops? What can influence whether growers plant refuge crops? And what factors affect a grower's willingness to plant refuge crops?To address these questions, Reisig talked with several hundred corn growers in more than a dozen counties in eastern North Carolina.Reisig found that approximately 40 percent of corn growers who used Bt corn would not plant refuge crops in the next growing season, while another 25 percent weren't sure. However, a majority of growers did understand the value of refuge crops -- and felt they should be planting them.Reisig also found that there was a high correlation between how much land was devoted to corn, cotton and soybeans in a county, and how likely farmers in that county were to plant refuge crops. The more land being devoted to crops, the more likely farmers were to plant refuge."Some of the resistance to planting refuge may be due to a lack of understanding about how important refuge crops are," Reisig says. "But it's also likely to be a function of the fact that many of the farms in counties with low refuge crop compliance are smaller operations. Growers may simply be trying to get more crop yield from their acreage -- though there is little evidence of short-term benefit, and ample evidence of long-term risk from Bt-resistant pests."Reisig also found that better enforcement and peer pressure from other farmers weren't seen as making farmers more likely to plant refuge crops. Instead, growers said that financial incentives -- such as rebates on non-Bt seed -- would make them more likely to plant refuge crops, as would the availability of high-yield non-Bt seed."This study is really a starting point," Reisig says. "We know this is a problem. I'm looking for partners in the social sciences to help me figure out how we can help growers make informed decisions and protect the long-term viability of their crops." | Genetically Modified | 2,017 |
March 30, 2017 | https://www.sciencedaily.com/releases/2017/03/170330092820.htm | Napping flies have higher resistance to deadly human pathogen | A new University of Maryland study has found that fruit flies genetically coded to take frequent naps had the strongest resistance to both a fungal infection and to a bacteria that the World Health Organization says is one of the world's most dangerous superbugs for humans. | Researchers study the common fruit fly, Such fly research also may inform efforts to develop new methods to control other insects, such as mosquitoes, which have been called the most dangerous animals on Earth because they are vectors for major human diseases such as malaria, encephalitis and Zika.The current study, recently published in the peer-reviewed journal "We found that flies resistant to the fungus were also resistant to the Pseudomonas bacteria and that the most resistant flies were those that tend to take lots of naps," said senior author Raymond St. Leger, a Distinguished University Professor in UMD's department of Entomology, which is part of both the university's College of Agriculture and Natural Resources and its College of Computer Mathematical and Natural Sciences. "We speculate that frequent naps charge up the immune system allowing the fly to meet new disease challenges when it's awake."St. Leger and his two UMD colleagues, graduate student and first author of the paper Jonathan Wang, and post-doctoral associate Hsiao-Ling Lu also found some of the flies carried variants of genes that greatly increased resistance to either the fungus or the bacteria. However, these disease resistance variants were rare, indicating that they also carried negative consequences that kept them from being evolutionarily advantageous enough to increase in the overall population over time."The finding that flies resistant to the fungus were also resistant to the bacteria was surprising, because some components of the fly immune system tackle bacteria while other components tackle fungi, just as it happens in humans," said Wang. "We had assumed before the study began that there might be a tradeoff so that resistance to the fungus might be at the expense of resistance to the bacteria. The finding of dual resistance to the two different pathogens indicates that the genes regulating generalized physiological factors played a bigger role in overall resistance than did the genes conferring disease-specific resistance."The authors write that their new findings provide a "starting point for further research on these important traits." | Genetically Modified | 2,017 |
March 23, 2017 | https://www.sciencedaily.com/releases/2017/03/170323132532.htm | Scientists reveal hidden structures in bacterial DNA | DNA contains the instructions for life, encoded within genes. Within all cells, DNA is organised into very long lengths known as chromosomes. In animal and plant cells these are double-ended, like pieces of string or shoelaces, but in bacteria they are circular. Whether stringy or circular, these long chromosomes must be organised and packaged inside a cell so that the genes can be switched on or off when they are required. | Working together with colleagues in Spain, Japan and Australia, researchers led by Luis Serrano, ICREA research professor and leader of the Design of Biological Systems laboratory at the Centre for Genomic Regulation, focused their attention on the organisation of DNA within an organism with an extremely small genome -- the pneumonia pathogen Using a technique called Hi-C, which reveals the interactions between different pieces of DNA, the researchers created a three-dimensional 'map' of the Notably, the CRG team, which counted with the expertise in The scientists also used the Hi-C technique to study more detailed patterns of organisation within the However, it was thought that these domains would not be found in Intriguingly, the CRG team found that even the tiny Marie Trussart, the lead author on the paper, said: "Studying bacteria with such a small genome was a big technical challenge, especially because we were using super-resolution microscopy, and it took us five years to complete the project. We had suspected that the The discovery suggests that this level of organisation and genetic control is common to all living cells, from the largest to the smallest, and can be achieved with little more than a handful of DNA binding proteins and the structural properties of the DNA itself.The CRG team has been working for a long time to achieve detailed quantitative analyses of | Genetically Modified | 2,017 |
March 22, 2017 | https://www.sciencedaily.com/releases/2017/03/170322153247.htm | Research questions effectiveness of translocation conservation method | New research by University of Arkansas biologists suggests that supplementing the numbers of a threatened species with individuals from other locations might not be as effective for some species as previously thought. | The technique, known as translocation, is a valid conservation measure and offers the potential of increasing genetic diversity in small, isolated populations threatened with extinction. Examples of its use include the European adder, bighorn sheep, the Florida panther and the greater prairie chicken in Illinois.But a recent study of the prairie chicken using modern DNA genotyping indicated a translocation program that took place in the 1990s temporarily increased the populations of birds in two Illinois counties but did not increase overall genetic diversity."We can now look back and say they faded again very quickly," said Michael Douglas, a professor in the Biological Sciences Department. "It really wasn't a rescue; it was an enhancement."Douglas co-authored the study, published in the journal Royal Society Open Science, with his wife Marlis, also a U of A biology professor, and U of A graduate student Steven Mussmann, who was the lead author. Colleagues at the Illinois Natural History Survey and the Illinois Department of Natural Resources were also co-authors.Prairie chickens once numbered in the millions in Illinois, but the populations dwindled to just 46 birds by 1998, primarily due to habitat loss. A translocation program in the mid 1990s moved birds from Kansas, where they are not threatened, and was thought to have rescued the Illinois population from harmful effects of low genetic diversity -- inbreeding.U of A biologists extracted DNA from 1,831 shed feathers gathered in six "leks," or breeding areas, in two Illinois counties. They found little evidence that genetic diversity had improved in the established populations, indicating that many of the translocated birds may not have extensively interbred with the local birds or may have simply wandered off."It didn't have the genetic rescue effect," said Marlis Douglas. "That doesn't mean translocations are wrong. They bought time."Augmenting habitat suitable for prairie chickens by conserving natural prairie and rehabilitating farmland would help increase population and genetic diversity, she said. "The best way to maintain a genetically diverse population is to increase population size. To do that you need more habitat." | Genetically Modified | 2,017 |
March 16, 2017 | https://www.sciencedaily.com/releases/2017/03/170316120505.htm | New plant research solves a colorful mystery | Research led by scientists at the John Innes Centre has solved a long-standing mystery by deducing how and why strange yet colourful structures called 'anthocyanic vacuolar inclusions' occur in some plants. | Pansy petals, blueberries and autumn leaves all have something in common -- their characteristic purple, blue and orange-red colours are all caused by the accumulation of pigment molecules called anthocyanins.As well as contributing to a wide range of plant colours, the patterns and shading caused by anthocyanins can help to guide pollinators towards flowers, or animals towards fruits for seed dispersal. Anthocyanins also help to protect plants against the destructive photo-oxidative damage that can be caused by various stresses including high levels of ultraviolet light.It has been known for some time that anthocyanins accumulate in the vacuoles of plant cells and, being soluble, they are usually uniformly distributed throughout the vacuole. However, previous research has also noted that, in some plants, distinct, densely coloured clusters of anthocyanins can form within the vacuoles.Until now, it was not known how these unusual 'anthocyanic vacuolar inclusions' (AVIs) formed -- or indeed why. However, a study led by the John Innes Centre's Professor Cathie Martin and published in the journal Several other John Innes Centre researchers were also involved in the research, along with international collaborators from China, New Zealand and Norway.The tobacco plant (Nicotiana tabacum), which is commonly used as a model organism in plant research, does not normally produce high levels of anthocyanins. However, by genetically modifying tobacco plants to produce proteins from the magenta-coloured snapdragon flower, the team observed the formation of the vacuole-soluble form of anthocyanins.The study's first author, Dr Kalyani Kallam of the John Innes Centre, said, "By crossing our soluble anthocyanin-producing tobacco plants with genetically modified lines expressing proteins from plants that modify anthocyanins we generated progeny tobacco plants that formed AVIs. By experimenting with different genes and conditions, we could work out the chemical steps involved in forming AVIs. Furthermore, we deduced that AVIs are not bound by a membrane, they are formed when anthocyanins precipitate out of solution in the vacuole, and this is dependent upon pH."Professor Cathie Martin said, "In many plants, the formation of AVIs is most likely an unavoidable chemical behaviour of specific anthocyanins under certain conditions. However, in some plants -- like Lisianthus (also known as Prarie Gentian), which has a very darkly pigmented central region in its flower petals -- AVIs may help to increase the intensity of pigmentation to help attract pollinators or seed dispersers." | Genetically Modified | 2,017 |
March 16, 2017 | https://www.sciencedaily.com/releases/2017/03/170316112147.htm | Viruses created to selectively attack tumor cells | Scientists at the IDIBAPS Biomedical Research Institute and at the Institute for Research in Biomedicine (IRB Barcelona) lead a study in which they have designed a new strategy to get genetically modified viruses to selectively attack tumor cells without affecting healthy tissues. The study, published today by the journal | Conventional cancer treatment may cause undesirable side effects as a result of poor selectivity. To avoid them it is important that new therapies can efficiently remove cancer cells and preserve the healthy ones. One of the new approaches in cancer therapy is based on the development of oncolytic viruses, ie, viruses modified to only infect tumor cells. In recent years several studies have been focused on the development of viruses created by genetic engineering to maximize their anticancer effect but, as their potency increases, so does the associated toxicity. Limiting this effect on healthy cells is now the key for the application of this promising therapy.In the study published in the journal CPEB is a family of four RNA binding proteins (the molecules that carry information from genes to synthesize proteins) that control the expression of hundreds of genes and maintain the functionality and the ability to repair tissues under normal conditions. When CPEBs become imbalanced, they change the expression of these genes in cells and contribute to the development of pathological processes such as cancer. "We have focused on the double imbalance of two of these proteins in healthy tissues and tumors: on the one hand we have CPEB4, which in previous studies we have shown that it is highly expressed in cancer cells and necessary for tumor growth; and, on the other hand, CPEB1, expressed in normal tissue and lost in cancer cells. We have taken advantage of this imbalance to make a virus that only attacks cells with high levels of CPEB4 and low CPEB1, that means that it only affects tumor cells, ignoring the healthy tissues," says Méndez."In this study we have worked with adenoviruses, a family of viruses that can cause infections of the respiratory tract, the urinary tract, conjunctivitis or gastroenteritis but which have features that make them very attractive to be used in the therapy against tumors," explains Cristina Fillat. To do this, it is necessary to modify the genome of these viruses. In the study researchers have inserted sequences that recognize CPEB proteins in key regions for the control of viral proteins. Their activity was checked in in vitro models of pancreatic cancer and control of tumor growth was observed in mouse models.The oncoselective viruses created in this study were very sophisticated, being activated by CPEB4 but repressed by CPEB1. Thus, researchers achieved attenuated viral activity in normal cells, while in tumor cells the virus potency was maintained or even increased. "When the modified viruses entered into tumor cells they replicated their genome and, when going out, they destroyed the cell and released more particles of the virus with the potential to infect more cancer cells," says Fillat. She adds that, "this new approach is very interesting since it is a therapy selectively amplified in the tumor."Since CPEB4 is overexpressed in several tumors, this oncoselective strategy may be valid for other solid tumors. Researchers are now trying to combine this treatment with therapies that are already being used in clinical practice, or that are in a very advanced stage of development, to find synergies that make them more effective. | Genetically Modified | 2,017 |
March 16, 2017 | https://www.sciencedaily.com/releases/2017/03/170316092847.htm | Outwitting climate change with a plant 'dimmer'? | Plants possess molecular mechanisms that prevent them from blooming in winter. Once the cold of win-ter has passed, they are deactivated. However, if it is still too cold in spring, plants adapt their blooming behavior accordingly. Scientists from the Technical University of Munich (TUM) have discovered genetic changes for this adaptive behavior. In light of the temperature changes resulting from climate change, this may come in useful for securing the production of food in the future. | Everyone knows that many plant species bloom at different times in spring. The time at which a plant blooms in spring does not follow the calendar, but is instead determined by environmental factors such as temperature and day length. Biologists have discovered that plants recognize these environmental factors via genetically determined programs and adapt their growth accordingly.In order to adapt to new climate zones and to ensure the evolutionary success of the species, these genetic programs may be adapted over the course of evolution. These adaptive processes take place passively: Minor changes (mutations) take place in the genetic material (DNA sequence) of the genes involved. If an adaptation proves successful over the following years, a new population establishes itself as a genetically distinct subspecies.In order to find out which mutations were used particularly frequently over the course of evolution, scientists compare biological adaptations such as shifts in the point in time at which blooming takes place with existing genetic changes. For many plant species, such as the thale cress (In the journal FLM binds directly to DNA, allowing it to influence the creation of other genes (transcription), which delays bloom-ing. Via comparisons of the FLM DNA sequence from over a thousand subspecies, Lutz was able to determine which genetic changes occurred frequently as this plant evolved: Generally speaking, these are the changes that provide the plant with an adaptive advantage found in a large number of subspecies. Mutations that did not pro-vide an advantage, on the other hand, were lost over time. The frequency of the changes is therefore an indication that these mutations were the most successful from an evolutionary point of view.For the FLM gene he characterized, Lutz was able to demonstrate that the genetic changes that occur worldwide have an influence on how frequently and efficiently the FLM gene is read. As FLM is able to delay the point in time at which blooming occurs, a more intensive reading of the gene directly corresponds to later blooming. FLM be-haves much like a light dimmer that the plant uses to regulate gene activity -- and hence blooming -- on a continuous scale.The underlying gene changes influenced this reading of FLM. Modified DNA was found in the area of the gene 'switch' (promoter), which regulates how much of the FLM gene is produced. In addition, the mechanism of gene splicing could also be observed: As part of this process, parts are cut out of the interim gene product. The quantity of active FLM can also be adapted via genetic changes that impact gene splicing. Hence, a direct dependency was found between the point in time of blooming and the quantity of the FLM gene, which in "The FLM variants we identified are ideal candidate genes that thale cress can use to adapt the point in time at which blooming takes place to the temperature changes caused by climate change," said Professor Claus Schwechheimer from the Chair of Plant Systems Biology at TUM.Temperature changes of just a few degrees Celsius during the growth phase of crop plants such as canola or sugar beets have a negative impact on agricultural production. In the future, the findings obtained by the team including the TUM scientists may allow the FLM gene to be used as a regulator to help adapt the blooming period to different temperatures as a result of climate change. With this knowledge, the goal of efficient food production over the long term is now within reach. | Genetically Modified | 2,017 |
March 9, 2017 | https://www.sciencedaily.com/releases/2017/03/170309171120.htm | Federal U.S. agencies need to prepare for greater quantity, range of biotechnology products | A profusion of biotechnology products is expected over the next five to 10 years, and the number and diversity of new products has the potential to overwhelm the U.S. regulatory system, says a new report from the National Academies of Sciences, Engineering, and Medicine. The U.S. Environmental Protection Agency, the Food and Drug Administration, the U.S. Department of Agriculture, and other agencies involved in regulating biotechnology products should increase their scientific capabilities, tools, and expertise in key areas of expected growth, said the committee that conducted the study and wrote the report. | "The rate at which biotechnology products are introduced -- and the types of products -- are expected to significantly increase in the next five to 10 years, and federal agencies need to prepare for this growth," said committee chair Richard Murray, Thomas E. and Doris Everhart Professor of Control and Dynamical Systems and Bioengineering, California Institute of Technology. "We hope this report will support agency efforts to effectively evaluate these future products in ways that ensure public safety, protect the environment, build public confidence, and support innovation."The U.S. biotechnology economy is growing rapidly, with the scale, scope, and complexity of products increasing. More types of organisms will likely be engineered, the report notes, and the kinds of traits introduced with biotechnology will also increase. Some future biotechnology products are likely to use genome-editing techniques such as CRISPR for familiar applications, such as modifying agricultural crops. Other future products are expected to be entirely new -- plants that can serve as sentinels of environmental contamination, for example, and collections of microorganisms that can produce chemical compounds efficiently. Engineered microbes, plants, and insects designed to live in the environment with little or no human management are likely to be more common. With few exceptions, products such as these have not yet been evaluated by the current regulatory system.Current staffing levels, expertise, and resources available at EPA, FDA, USDA and other agencies may not be sufficient to address the expected scope and scale of future biotechnology products, the report says. It is critical that the agencies involved in regulation develop and maintain scientific capabilities, tools, and expertise in key evolving areas. Examples of such areas include understanding relationships between intended genetic changes and an organism's observable traits, the unintended effects of genetic changes on target and non-target organisms, predicting and monitoring ecosystem responses, and quantifying the economic and social costs and benefits of biotechnologies.To respond to the expected increase and diversity of products, the agencies should develop risk-analysis approaches tailored to the familiarity of products and the complexity of their uses, the report says. For biotechnology products that are similar to products already in use, established risk-analysis methods can be applied or modified, and a more expedited process could be used. For products that have less-familiar characteristics or more complex risk pathways, new risk-analysis methods may need to be developed. Regulatory agencies should build their capacity to rapidly determine the type of risk-analysis approaches most appropriate for new products entering the regulatory system.EPA, FDA, and USDA should identify products that could serve as pilot projects to develop new approaches to assess risks and benefits and to inform regulatory decisions, the report says. Pilot projects could also be used by the agencies to evaluate future products as they move from laboratory scale, to field- or prototype-scale, to full-scale operation.One challenge regulators will face is finding jurisdiction under existing statutes to regulate the diverse range of anticipated biotech products, the report says. The current collection of statutes and regulations that provide the basis for agencies' oversight, known as the Coordinated Framework for Regulation of Biotechnology, appears to have considerable flexibility to cover a wide range of biotechnology products, but in some cases the agencies' jurisdiction has been defined in ways that could leave gaps or overlaps in regulatory oversight. At times, FDA, EPA, and USDA may need to make use of the flexibility under their statutes to minimize gaps in jurisdiction.Even when statutes do allow agencies to regulate products, the current statutes may not adequately equip regulators with the tools to regulate the products effectively, the committee said. For example, the statutes may not empower regulators to require product sponsors to share in the burden of generating information about product safety, and may place the burden of proof on regulators to demonstrate that a product is unsafe before they can take action to protect the public. This implies that adequate federal support for research will be crucial to protect consumer and occupational safety and the environment.Biotechnology products on the horizon are likely to generate substantial public debate, the report notes. Many members of society have concerns over the safety and ethics of various biotechnologies, while others see prospects for biotechnology addressing social or environmental problems. The U.S. regulatory system will need to achieve a balance among competing interests, risks, and benefits when considering how to manage development and use of new biotech products.In addition, more research may be needed to develop methods for governance systems that integrate ethical, cultural, and social implications into risk assessments in ways that are meaningful. This may not be feasible or even justified for all new biotechnology products -- such as products with which there is already familiarity or products that will not be released into the environment. For example, genetically engineered organisms used in the research laboratory to develop new chemical synthesis methods are not likely to require the same level of public dialogue as products that have more uncertainty associated with them, such as organisms with gene drives, which enhance organisms' ability to pass certain genetic traits on to their offspring.Overall, the federal government should develop a strategy that scans the horizon for new biotechnology products, identifying and prioritizing those products that are less familiar or that present a need for more complex risk analysis, the report says. The federal government should also work to establish appropriate federal funding levels for sustained, multiyear research to develop the necessary advances in regulatory science. To this end, the National Science Foundation, the U.S. Department of Defense, the U.S. Department of Energy, the National Institutes of Standards and Technology, and other agencies that fund biotechnology research should increase their investments in regulatory science. | Genetically Modified | 2,017 |
March 8, 2017 | https://www.sciencedaily.com/releases/2017/03/170308145347.htm | Dampened immunity during pregnancy promotes evolution of more virulent flu | During pregnancy, a mother's immune system is suppressed to protect the fetus, which is perceived as a foreign body because it is genetically different. A study in mice found that suppressed immunity during pregnancy creates a window of opportunity for the H1N1 influenza virus to infect the mother and to rapidly, within a few days, mutate into a more virulent strain. The findings appear in | "The first line of defense of the immune system, the innate immune response, is not acting quickly enough to clear the virus," says co-lead author Gülsah Gabriel, a virologist at the Heinrich Pette Institute, Leibniz Institute for Experimental Virology in Hamburg, Germany. "The virus takes advantage of this permissive environment and mutates very fast. This is what influenza viruses do best. The new variants are responsible for increased virulence."For the last century, study after study has shown that pregnant women suffer more severely from influenza than non-pregnant women. A 2010 World Health Organization analysis of the 2009 H1N1 influenza pandemic found that pregnant women were 7 times more likely to be hospitalized and twice as likely to die from H1N1 infection than non-pregnant women.In response, Gabriel and co-lead author Petra Clara Arck, a reproductive immunologist at the University Medical Center in Hamburg, joined forces to understand the biology behind these observations. Previous studies of influenza evaluated mice that were pregnant with genetically identical fetuses, called syngenic pregnancies. These pregnancies do not mimic natural human pregnancies, in which babies are the product of the combined genes of a mother and father.So, using mice, Gabriel and Arck also studied allogenic pregnancies, in which the fetuses differ genetically from the mother. In allogenic pregnancies, they found that the immune system is more suppressed than in syngenic pregnancies.The immune system typically mounts waves of defense against viral infections. Cells in the innate immune system respond immediately by secreting inflammatory factors called cytokines to stop the spread of infection. As the infection progresses, adaptive immune cells called T cells move to the area of infection, where they detect and kill infected cells.To understand immune suppression in mice with genetically distinct pregnancies, the researchers examined gene expression patterns in immune cells during infection. They found that the genes responsible for releasing cytokines were suppressed, resulting in a weak initial response to infection. In addition, genes responsible for activating and recruiting T cells to an infection were also suppressed. "The entire immune system is damped down to protect the fetus," says Arck.Influenza appears to take immediate advantage of the mother's vulnerability, according to the study. During the first days of infection, a typical innate immune response will stop the spread. But during pregnancy, the initial response is not strong enough to stop the virus. Rather, surviving viral invaders have time to mutate and produce a range of variants, some of which are more likely to cause a severe infection.The most frequent mutation the researchers found in influenza in pregnant mice was a variant that further dampens the innate immune response, giving the virus an even better chance to survive and thrive. "In this environment of a dampened innate immune system, the virus has a chance to escape and become more virulent," says Gabriel. "This suggests that during pregnancy, a typical influenza infection could hit very hard."To determine if pregnant women experience a similar evolution of influenza infection, Gabriel and Arck are planning to look for similar mutations in samples from pregnant women who suffered from influenza. Similar mutations have been seen in other influenza cases in pregnant women, but not in studies large enough to confirm that they are more frequent than other variants.If a larger study confirms that these variants are seen more commonly in pregnant women, that would further strengthen the importance of influenza vaccinations for pregnant women. "The best bet for pregnant women is to be vaccinated to prevent infection, because influenza viruses are very good at escaping," says Gabriel.In response to the 2009 H1N1 influenza pandemic, the World Health Organization made pregnant women the number one priority for vaccination, with a goal of vaccinating 75% of this population. The flu shot is safe and protects both the mother and the fetus from infection. According to the CDC, in the US in 2016, about 50% of pregnant women got the flu shot, an improvement over the 20% vaccinated in 2009. | Genetically Modified | 2,017 |
March 8, 2017 | https://www.sciencedaily.com/releases/2017/03/170308092502.htm | A new tool for genetically engineering the oldest branch of life | A new study by G. William Arends Professor of Microbiology at the University of Illinois Bill Metcalf with postdoctoral Fellow Dipti Nayak has documented the use of CRISPR-Cas9 mediated genome editing in the third domain of life, Archaea, for the first time. Their groundbreaking work, reported in | "Under most circumstances our model archaeon, "Even more," continues Nayak, "with our previous techniques, mutations had to be introduced one step at a time. Using this new technology, we can introduce multiple mutations at the same time. We can scale up the process of mutant generation exponentially with CRISPR."CRISPR, short for Clustered Regularly Interspaced Short Palindromic Repeats, began as an immune defense system in archaea and bacteria. By identifying and storing short fragments of foreign DNA, Cas (CRISPR-associated system) proteins are able to quickly identify that DNA in the future, so that it can then quickly be destroyed, protecting the organism from viral invasion.Since its discovery, a version of this immune system -- CRISPR-Cas9 -- has been modified to edit genomes in the lab. By pairing Cas9 with a specifically engineered RNA guide rather than a fragment of invasive DNA, the CRISPR system can be directed to cut a cell's genome in an arbitrary location such that existing genes can be removed or new ones added. This system has been prolifically useful in editing eukaryotic systems from yeast, to plant, to fish and even human cells, earning it the American Association for the Advancement of Science's 2015 Breakthrough of the Year award. However, its implementation in prokaryotic species has been met with hurdles, due in part to their different cellular processes.To use CRISPR in a cellular system, researchers have to develop a protocol that takes into account a cell's preferred mechanism of DNA repair: after CRISPR's "molecular scissors" cut the chromosome, the cell's repair system steps in to mend the damage through a mechanism that can be harnessed to remove or add additional genetic material. In eukaryotic cells, this takes the form of Non-Homologous End Joining (NHEJ). Though this pathway has been used for CRISPR-mediated editing, it has the tendency to introduce genetic errors during its repair process: nucleotides, the rungs of the DNA ladder, are often added or deleted at the cut site.NHEJ is very uncommon in prokaryotes, including Archaea; instead, their DNA is more often repaired through a process known as homology-directed repair. By comparing the damage to a DNA template, homology-directed repair creates what Nayak calls a "deterministic template" -- the end result can be predicted in advance and tailored to the exact needs of the researcher.In many ways, homology-directed repair is actually preferable for genome editing: "As much as we want CRISPR-Cas9 to make directed edits in eukaryotic systems, we often end up with things that we don't want, because of NHEJ," explains Nayak. "In this regard, it was a good thing that most archaeal strains don't have a non-homologous end joining repair system, so the only way DNA can be repaired is through this deterministic homologous repair route."Though it may seem counter-intuitive, one of Nayak and Metcalf's first uses of CRISPR-Cas9 was to introduce an NHEJ mechanism in Methanosarcina acetivorans. Though generally not preferable for genome editing, says Nayak, NHEJ has one use for which it's superior to homologous repair: "If you just want to delete a gene, if you don't care how ... non-homologous end joining is actually more efficient."By using the introduced NHEJ repair system to perform what are known as "knock-out" studies, wherein a single gene is removed or silenced to see what changes are produced and what processes that gene might affect, Nayak says that future research will be able to assemble a genetic atlas of M. acetivorans and other archaeal species. Such an atlas would be incredibly useful for a variety of fields of research involving Archaea, including an area of particular interest to the Metcalf lab, climate change."Methanosarcina acetivorans is the one of the most genetically tractable archaeal strains," says Nayak. "[Methanogens are] a class of archaea that produce gigatons of this potent greenhouse gas every year, play a keystone role in the global carbon cycle, and therefore contribute significantly to global climate change." By studying the genetics of this and similar organisms, Nayak and Metcalf hope to gain not only a deeper understanding of archaeal genetics, but of their role in broader environmental processes.In all, this research represents an exciting new direction in studying and manipulating archaea. "We began this research to determine if the use of CRISPR-Cas9 genome editing in archaea was even possible," concludes Nayak. "What we've discovered is that it's not only possible, but it works remarkably well, even as compared to eukaryotic systems." | Genetically Modified | 2,017 |
March 3, 2017 | https://www.sciencedaily.com/releases/2017/03/170303143229.htm | Microbiome diversity is influenced by chance encounters | Within the human digestive tract, there are trillions of bacteria, and these communities contain hundreds or even thousands of species. The makeup of those populations can vary greatly from one person to another, depending on factors such as diet, environmental exposure, and health history. | A new study of the microbe populations of worms offers another factor that may contribute to this variation: chance.MIT researchers found that when they put genetically identical worms into identical environments and fed them the same diet, the worms developed very different populations of bacteria in their gut, depending on which bacteria happened to make it there first."This study shows that you can have heterogeneity that's driven by the randomness of the initial colonization event. That's not to say the heterogeneity between any two individuals has to be driven by that, but it's a potential source that is often neglected when thinking about this variation," says Jeff Gore, the Latham Family Career Development Associate Professor of Physics at MIT.Gore is the senior author of the study, which appears in the March 3 issue of the journal Variations in the human gut microbiome have been shown to contribute to gastrointestinal disorders such as colitis and Crohn's disease, and studies suggest that microbiome composition can also influence diabetes, heart disease, and cancer."We know that gut communities are different within different individuals, and that this could have really important implications for health and disease, but it's often difficult to figure out the origin of this diversity between different individuals," Gore says.The researchers chose to study the worm "What you would like to do is take a bunch of identical individuals, place them in identical environments, and then look to see whether the microbial communities are the same or different. That's a very difficult experiment to do with people, but with model organisms it's feasible," Gore says.The researchers explored this further by feeding the worms a mix of only two types of bacteria, making it easier to study their interactions. In this scenario, all of the bacteria were After a week of this diet, each worm had about 30,000 bacteria in its digestive tract. However, these populations were not evenly divided between red and green. Instead, each population was dominated by one or the other. This happens, Gore says, because the initial colonization of the gut is a rare event, so whichever microbe makes it there first tends to dominate the entire population."Whichever color bacteria is lucky and happens to survive getting eaten and sticks to the gut, this bacterium starts growing, and it can grow to dominate the gut community," he says.This randomness tends to prevail when the colonization rate is low. When the researchers fed the worms larger amounts of bacteria, the colonization rate went up and the researchers found much less variation among individuals' microbe populations.The researchers also found the same effect when they fed the worms two different species of bacteria: Gore says that this random variability may contribute to the differences in microbe populations seen in the human gut as well, since usually only a small fraction of bacteria consumed by humans and other animals survives the digestion process. However, many other factors such as environmental exposure also play roles, he says."I don't believe that stochastic colonization is the only or dominant source of heterogeneity between individuals, but I think it's a source of heterogeneity that is often overlooked," Gore says.His lab is now studying many different pairs of bacterial species in the worm gut to see if the outcome of competition between two species can be used to predict the outcome when three or more species are competing. | Genetically Modified | 2,017 |
March 1, 2017 | https://www.sciencedaily.com/releases/2017/03/170301130511.htm | Nature can beat back scientific tinkering with genes of entire species | Rest easy, folks. Armies of genetically modified super-species are unlikely to conquer Earth anytime soon. | In a paper recently appearing in the journal For decades, scientists have proposed various methods of genetically altering natural populations to solve problems that plague human beings."A lot of times nature interferes with how humans would like the world to be," said lead author Robert Unckless, assistant professor of molecular biosciences at KU. "Good examples of that are pests in crops and insect-vectored diseases, like the Zika virus or dengue or malaria."Discussions of modifying specific genes at the population level had been mostly theoretical, because genetic edits pushed through a population also tended to have a "fitness cost," decreasing the life span of altered individuals, or rendering them sterile. So natural selection favors individuals lacking modified genes and purges a given genetic alteration within a population within a few generations.But scientists gained a new edge with the advent of techniques using "selfish genes" that take advantage of natural elements to cheat genetic "Mendelian inheritance" -- whereby offspring of modified and nonmodified organisms are just as likely to inherit traits from either parent -- and overcome the fitness cost."There are several examples of selfish genetic elements that cheat Mendelian laws, so instead of 50 percent chance of a modified gene transferring to offspring, they have an 80 or 90 percent chance," said Unckless. "By doing that they spread through a population much more quickly."The KU researcher said by tying the mutation for shorter lifespan, or resistance to dengue fever in mosquitoes, for example, to one of these selfish genetic elements that can drive through populations, scientists found a way to overcome fitness cost. "It's compensated for by the Mendelian cheating going on, so you can spread it through a population. It's known as it 'gene drive.'" Unckless said despite its promise, the approach "more or less stalled out" until two years ago when researchers in California incorporated CRISPR/Cas9 into their gene drive constructs. Suddenly, dreams of creating super mosquitoes to eradicate disease were alive again."This gene drive idea, CRISPR/Cas9, in nature is a bacterial immune defense system -- but it's been co-opted in genetics labs all over the world to target particular sequences and create mutations of those sequences," he said.The KU researcher said the CRISPR/Cas9 approach identifies a targeted genetic sequence and creates a mutation there -- inserting itself as the genetic mechanism of that sequence of DNA."So science has now created a mechanism to recognize a sequence, cut it and insert the genetic material that we want," Unckless said. "That might include the CRISPR/Cas9 machinery but also a new gene that provides resistance to dengue fever in the mosquito, for example, so the two spread together. In only a handful of generations you go from having almost no copies of the mutation in the population to it being 'fixed' so every individual in the population has it -- at least that was the simple theory." Yet, faced with the new and sophisticated CRISPR/Cas9 method of gene drive, nature is still likely to fight back to resist the mutation successfully, Unckless said."We expect that resistance alleles will pop up either before the drive can spread, or after the drive spreads, and eventually replace the drive," he said. "If your goal is to get resistance to dengue into the population, you might do that -- and it might persist for a few generation or a few hundred generations -- but then it decays and leaves behind resistance alleles." In the new "Basically, looking at the numbers and assuming a simple gene drive system, it's a foregone conclusion that resistance will evolve," Unckless said. "That's the main idea. We argue resistance could be thought of as a good thing -- if we know it's going to evolve, we can plan around it, and understand a gene drive is a temporary solution. Say we know the half-life of this genetic solution is x number of generations, we can monitor it and as resistance starts to evolve we can create a new one."Unckless said CRISPR/Cas9 creates a double-strand break of DNA, which the organism repairs via one of two methods, known as "nonhomologous end joining" (NHEJ) and "homology-directed repair.""If you had to fix your car because you knew a piece of the engine was missing, and your solution was 'I'm going to just take connect pieces in a random way -- that's NHEJ," he said. "Obviously that doesn't work most of the time. On the other hand, there's homology-directed repair. It uses a template, which is usually another chromosome -- because there's usually two copies. It's like the perfect template for repairing your 2007 Honda Civic. You go to your neighbor who has the same car and compare them and say, 'That's what's wrong and you fix it based on that."But organisms use both NHEJ and homology-directed repair. For a CRISPR/Cas9 gene drive to be most effective, it must be "tuned" toward homology-directed repair."If you don't, NHEJ is going to screw things up because it creates resistance alleles," Unckless said.The researchers conclude that, like other attempts to manipulate populations, gene drive is likely to lead to resistance alleles. However, with this known, scientists can prepare appropriately for a dynamic gene drive system with new constructs responding to the appearance of resistance alleles."You need to monitor gene drive," he said. "As you see resistance come up you introduce something new that will overcome resistance." | Genetically Modified | 2,017 |
February 22, 2017 | https://www.sciencedaily.com/releases/2017/02/170222131439.htm | Scientists discover how essential methane catalyst is made | New ways to convert carbon dioxide (CO | Recycling COThis challenge inspired a team of scientists led by Professor Martin Warren, of the University of Kent's School of Biosciences, to investigate how a key molecule, coenzyme F430, is made in these bacteria.Although F430 -- the catalyst for the production process -- is structurally very similar to the red pigment found in red blood cells (haem) and the green pigment found in plants (chlorophyll), the properties of this bright yellow coenzyme allow methanogenic bacteria to breathe in carbon dioxide and exhale methane.By understanding how essential components of the process of biological methane production, methanogenesis, such as coenzyme F430 are made scientists are one step closer to being able to engineer a more effective and obliging methane-producing bacterium.The research teams have shown that coenzyme F430 is made from the same starting molecular template from which haem and chlorophyll are derived, but uses a different suite of enzymes to convert this starting material into F430. Key to this process is the insertion of a metal ion, which is glued into the centre of the coenzyme.If the process of biological methane production (methanogenesis) could be engineered into bacteria that are easier to grow, such as the microbe E. coli, then engineered strains could be employed to catch carbon dioxide emissions and convert them into methane for energy production. | Genetically Modified | 2,017 |
February 22, 2017 | https://www.sciencedaily.com/releases/2017/02/170222102629.htm | Hybrid plant breeding: Secrets behind haploid inducers, a powerful tool in maize breeding | A common strategy to create high-yielding plants is hybrid breeding -- crossing two different inbred lines to obtain characteristics superior to each parent. However, getting the inbred lines in the first place can be a hassle. Inbred lines consist of genetically uniform individuals and are created through numerous generations of self-crossing. In maize, the use of so-called "haploid inducers" provides a short cut to this cumbersome procedure, allowing to produce inbred lines in just one generation. | A study by Laurine Gilles and colleagues, published today in Haploid inducers were first discovered in the 1950s. Pollination of female flower with pollen of a haploid inducer strain will yield offspring that are haploid, meaning that they will only contain one single copy of each gene as opposed to the usual two copies. All their genetic material comes from the mother. Treating these haploid plants with a chemical that causes chromosome doubling will lead to plants with two identical copies of all genes in just one generation. With classical inbreeding, this condition takes seven to ten years to achieve.Haploid offspring in maize are not unusual; they emerge naturally, albeit at a very low rate. Haploid inducers can bring this rate up to about 10% of the progeny being haploid -- enough to make it a useful tool for breeders. More than 50 years after the discovery of haploid inducers, Widiez and his team, in collaboration with Limagrain, have now identified the gene that mainly causes the phenomenon and termed it Not Like Dad to highlight the fact that its dysfunction induces embryos without genetic contribution from the father. The gene product is necessary for successful fertilization so that its failure promotes the formation of haploid embryos. Two other research groups have in parallel identified the same gene and come to similar conclusions.Haploid inducers are nowadays powerful breeding tools, but as yet the technology is restricted to maize, while in-vitro haploid induction in certain crops is labor-intense. Understanding the genes and molecular mechanism behind the process will help translate this technology to other crops. The identification of Not Like Dad is an important step to this end. While Not Like Dad is the most important contributor to haploid induction in inducer lines, there are at least seven more genes that play a role in increasing the rate of haploid offspring. Revealing their molecular identity, as well as understanding their mode of action, will be important to fully understand the process. | Genetically Modified | 2,017 |
February 21, 2017 | https://www.sciencedaily.com/releases/2017/02/170221130655.htm | Microbe, virus co-evolution: Model of CRISPR, phage co-evolution explains confusing experimental results | A Rice University study suggests that researchers planning to use the CRISPR genome-editing system to produce designer gut bacteria may need to account for the dynamic evolution of the microbial immune system. | CRISPR is an acquired immune system that allows bacteria and other single-celled organisms to store snippets of DNA to protect themselves from viruses called phages. The system allows a cell to "remember" and mount a defense against phages it has previously battled.Beginning in 2012, scientists discovered they could use CRISPR proteins to precisely edit the genomes of not only bacteria but also of animals and humans. That discovery captured Despite rapid advances in the use of CRISPR for editing genomes, scientists still have many questions about how CRISPR defenses evolved in bacteria and other single-celled prokaryotic organisms. Michael Deem, a physicist and bioengineer from Rice, was first drawn to CRISPR in 2010 and has created a number of computer models to explore CRISPR's inner workings.In a new study in the "There's a co-evolution between the phages and the bacteria," Deem said. "The bacteria are incorporating DNA from the phages, and this allows the bacteria or their offspring to be protected against those phages.Like all living things, phages, which attack only single-celled organisms, are constantly evolving. Deem said the rate at which they mutate and change their DNA sequence is one variable that can affect how well CRISPR can recognize and fight them. Another factor that must be taken into account in modelling CRISPR is that the limited space available for storing phage DNA. CRISPR is constantly acquiring new snippets and throwing out old ones. An additional parameter is the encounter rate, or how often the bacteria and phages come into contact."If we plot the results from a simple model that incorporates these parameters, we would see that the results fall into three regions, or phases, one where CRISPR wins out and drives the phages to extinction, one where the phages win and kill off the bacteria and a third phase where the two coexist," Deem said.Physicists often use such phase diagrams to probe the dynamics of systems. By altering the encounter and mutation rates, scientists can explore how particular combinations drive the system from one phase to another.In the new study, Deem and Han, who is now a software engineer at Google, found that certain combinations of encounter and mutation rates produced an unexpected result, a five-region phase diagram where phages twice thrived and were twice nearly killed off, thanks to the complex interplay between the CRISPR add-drop rates and the rate at which the bacteria were exposed to phages."Generally speaking, we might expect that at high rates of exposure, the CRISPR immune system would drive the phages to extinction because it would encounter them often enough to have a current copy of their DNA in the CRISPR," Deem said. "In our phase diagram, we refer to this as region four, and our first interesting finding is that while extinction is likely in this case, there is always a probability, which we can calculate, that the phages will escape and not go extinct. That natural variability is of interest."The second point is that as we lower the exposure rate of the phages to the bacteria, and there are now fewer phages infecting the bacteria per unit of time, the bacteria have decreased opportunities to acquire DNA from the phages, and the phages can now coexist with the bacteria" he said. "We call this region three. So, we've gone from extinction to nonextinction, and we now have coexistence. That's expected and very reasonable."Surprisingly, we found that lowering the exposure rate even more -- a case in which the bacteria now have even fewer opportunities to copy DNA into the CRISPR -- resulted in another phase where the phages were driven to extinction. That's region two. And people would not have expected that."In examining this result, Deem and Han found that the second extinction event occurred because the infection rate and the bacterial growth rate were the same, and any bacteria that acquired immunity to the phages would reproduce quickly enough to out-compete both all other bacteria and the phages. In this extinction event, a single copy of viral DNA in the CRISPR allowed the bacteria to defeat the phages. This differed from region four -- the high exposure case -- where many copies of DNA in the CRISPR allowed multiple strains of bacteria to defeat the phages.Deem said the results help explain previous experimental results that have confused the CRISPR research community."There's been some controversy about whether CRISPR can control phages and what circumstances lead to coexistence," Deem said. "The reason for this is that various experiments have produced results from regions two, three and four. Our results clarify the range of possibilities and confirm that this range has been at least partially measured."Deem said the findings apply only to CRISPR's use in bacterial and prokaryotic systems. In cases where researchers are trying to use CRISPR gene-editing tools to modify those organisms or the phages that affect them, the dynamics should be taken into account."For example, people will eventually start editing the microbiome, the community of beneficial gut bacteria and phages that help keep people healthy," Deem said. "There's a great deal of work being done now on engineering the microbiome to make people more healthy, to control obesity or mood, for instance. For those interested in engineering the phage-microbiome interaction, it will be important to account for these co-evolutionary subtleties." | Genetically Modified | 2,017 |
February 20, 2017 | https://www.sciencedaily.com/releases/2017/02/170220084156.htm | Switched-on DNA: Sparking nano-electronic applications | DNA, the stuff of life, may very well also pack quite the jolt for engineers trying to advance the development of tiny, low-cost electronic devices. | Much like flipping your light switch at home -- only on a scale 1,000 times smaller than a human hair -- an ASU-led team has now developed the first controllable DNA switch to regulate the flow of electricity within a single, atomic-sized molecule. The new study, led by ASU Biodesign Institute researcher Nongjian Tao, was published in the advanced online journal "It has been established that charge transport is possible in DNA, but for a useful device, one wants to be able to turn the charge transport on and off. We achieved this goal by chemically modifying DNA," said Tao, who directs the Biodesign Center for Bioelectronics and Biosensors and is a professor in the Fulton Schools of Engineering. "Not only that, but we can also adapt the modified DNA as a probe to measure reactions at the single-molecule level. This provides a unique way for studying important reactions implicated in disease, or photosynthesis reactions for novel renewable energy applications."Engineers often think of electricity like water, and the research team's new DNA switch acts to control the flow of electrons on and off, just like water coming out of a faucet.Previously, Tao's research group had made several discoveries to understand and manipulate DNA to more finely tune the flow of electricity through it. They found they could make DNA behave in different ways -- and could cajole electrons to flow like waves according to quantum mechanics, or "hop" like rabbits in the way electricity in a copper wire works -- creating an exciting new avenue for DNA-based, nano-electronic applications.Tao assembled a multidisciplinary team for the project, including ASU postdoctoral student Limin Xiang and Li Yueqi performing bench experiments, Julio Palma working on the theoretical framework, with further help and oversight from collaborators Vladimiro Mujica (ASU) and Mark Ratner (Northwestern University).To accomplish their engineering feat, Tao's group, modified just one of DNA's iconic double helix chemical letters, abbreviated as A, C, T or G, with another chemical group, called anthraquinone (Aq). Anthraquinone is a three-ringed carbon structure that can be inserted in between DNA base pairs but contains what chemists call a redox group (short for reduction, or gaining electrons or oxidation, losing electrons).These chemical groups are also the foundation for how our bodies' convert chemical energy through switches that send all of the electrical pulses in our brains, our hearts and communicate signals within every cell that may be implicated in the most prevalent diseases.The modified Aq-DNA helix could now help it perform the switch, slipping comfortably in between the rungs that make up the ladder of the DNA helix, and bestowing it with a new found ability to reversibly gain or lose electrons.Through their studies, when they sandwiched the DNA between a pair of electrodes, they careful controlled their electrical field and measured the ability of the modified DNA to conduct electricity. This was performed using a staple of nano-electronics, a scanning tunneling microscope, which acts like the tip of an electrode to complete a connection, being repeatedly pulled in and out of contact with the DNA molecules in the solution like a finger touching a water droplet."We found the electron transport mechanism in the present anthraquinone-DNA system favors electron "hopping" via anthraquinone and stacked DNA bases," said Tao. In addition, they found they could reversibly control the conductance states to make the DNA switch on (high-conductance) or switch-off (low conductance). When anthraquinone has gained the most electrons (its most-reduced state), it is far more conductive, and the team finely mapped out a 3-D picture to account for how anthraquinone controlled the electrical state of the DNA.For their next project, they hope to extend their studies to get one step closer toward making DNA nano-devices a reality."We are particularly excited that the engineered DNA provides a nice tool to examine redox reaction kinetics, and thermodynamics the single molecule level," said Tao. | Genetically Modified | 2,017 |
February 17, 2017 | https://www.sciencedaily.com/releases/2017/02/170217012456.htm | Honey bee genetics sheds light on bee origins | Where do honey bees come from? A new study from researchers at the University of California, Davis and UC Berkeley clears some of the fog around honey bee origins. The work could be useful in breeding bees resistant to disease or pesticides. | UC Davis postdoctoral researcher Julie Cridland is working with Santiago Ramirez, assistant professor of evolution and ecology at UC Davis, and Neil Tsutsui, professor of environmental science, policy and management at UC Berkeley, to understand the population structure of honey bees (Apis mellifera) in California. Pollination by honey bees is essential to major California crops, such as almonds. Across the U.S., the value of "pollination services" from bees has been estimated as high as $14 billion."We're trying to understand how California honey bee populations have changed over time, which of course has implications for agriculture," Ramirez said.To understand California bees, the researchers realized that they first needed to better understand honey bee populations in their native range in the Old World."We kind of fell into this project a little bit by accident," Cridland said. "Initially we were looking at the data as a preliminary to other analyses, and we noticed some patterns that weren't previously in the literature."The new study combines two large existing databases to provide the most comprehensive sampling yet of honey bees in Africa, the Middle East and Europe.Unrelated Bee Lineages in Close ProximityPreviously, researchers had assumed an origin for honey bees in north-east Africa or the Middle East. But the situation turns out to be more complicated than that, Cridland said."You might think that bees that are geographically close are also genetically related, but we found a number of divergent lineages across north-east Africa and the Middle East," she said.There are two major lineages of honey bees in Europe -- C, "Central European," including Italy and Austria and M, including Western European populations from Spain to Norway -- which give rise to most of the honey bees used in apiculture worldwide. But although C and M lineage bees exist side by side in Europe and can easily hybridize, they are genetically distinct and arrived in different parts of the world at different times.M lineage bees were the first to be brought to north America, in 1622. The more docile C lineage bees came later, and today many California bees are from the C lineage, but there is still a huge amount of genetic diversity, Ramirez said."You can't understand the relationships among bee populations in California without understanding the populations they come from," Cridland said.In the Middle East, the O lineage hails from Turkey and Jordan, and Y from Saudia Arabia and Yemen. The main African lineage is designated A.At this point, the researchers cannot identify a single point of origin for honey bees, but the new work does clear up some confusion from earlier studies, they said. In some cases, diverged lineages that happen to be close to each other have mixed again. Previous, more limited studies have sampled those secondarily mixed populations, giving confusing results."We're not making any strong claim about knowing the precise origin," Cridland said. "What we're trying to do is talk about a scientific problem, disentangling these relationships between lineages, the genetic relationships from the geography." | Genetically Modified | 2,017 |
February 15, 2017 | https://www.sciencedaily.com/releases/2017/02/170215084057.htm | Plant-made virus shells could deliver drugs directly to cancer cells | Viruses are extremely efficient at targeting and delivering cargo to cells. In the journal | For this work, Frank Sainsbury and colleagues copied the core protein shell of the Bluetongue virus, a pathogen that affects ruminant animals. Previous research has shown that the capsid is stable, has a large cavity for small molecules or proteins to pack into, and is easy to produce with high purity. The researchers wanted to try making the virus-shell nanoparticles using plants. This is an increasingly popular approach to producing pharmaceuticals as it minimizes possible contamination by human pathogens, which plants don't carry. But first they needed to understand the structure of the shells.Using single particle cryo-electron microscopy, the team showed for the first time that the recombinant shell nanoparticles produced by plants were different from the natural virus capsid. With the nanoparticles' detailed structure in hand, the researchers then genetically and chemically engineered them to their specifications, and loaded proteins and small molecules inside the shells. Lab testing showed that the plant-made virus particles, which naturally bind to receptors on cancer cells, were taken in by human breast cancer cells. The findings suggest the nanoparticles can potentially be used for the targeted delivery of drugs. | Genetically Modified | 2,017 |
February 13, 2017 | https://www.sciencedaily.com/releases/2017/02/170213131507.htm | Scientists create mouse that resists cocaine's lure | Scientists at the University of British Columbia have genetically engineered a mouse that does not become addicted to cocaine, adding to the evidence that habitual drug use is more a matter of genetics and biochemistry than just poor judgment. | The mice they created had higher levels of a protein called cadherin, which helps bind cells together. In the brain, cadherin helps strengthen synapses between neurons -- the gaps that electrical impulses must traverse to bring about any action or function controlled by the brain, whether it's breathing, walking, learning a new task or recalling a memory.Learning -- including learning about the pleasure induced by a stimulant drug -- requires a strengthening of certain synapses. So Shernaz Bamji, a Professor in the Department of Cellular and Physiological Sciences, thought that extra cadherin in the reward circuit would make their mice more prone to cocaine addiction.But she and her collaborators found the opposite to be true, as they explain in an article published today in Dr. Bamji and her collaborators injected cocaine into mice over a number of days and immediately placed in a distinctly decorated compartment in a three-room cage, so that they would associate the drug with that compartment. After several days of receiving cocaine this way, the mice were put into the cage and allowed to spend time in any compartments they preferred. The normal mice almost always gravitated to the cocaine-associated compartment, while the mice with extra cadherin spent half as much time there -- indicating that these mice hadn't formed strong memories of the drug.To understand that unexpected result, Dr. Bamji and her associates in UBC's Life Sciences Institute analyzed the brain tissue of the genetically engineered mice.They found that extra cadherin prevents a type of neurochemical receptor from migrating from the cell's interior to the synaptic membrane. Without that receptor in place, it's difficult for a neuron to receive a signal from adjoining neurons. So the synapses don't strengthen and the pleasurable memory does not "stick.""Through genetic engineering, we hard-wired in place the synapses in the reward circuits of these mice," says graduate student Andrea Globa, a co-lead author with former graduate student Fergil Mills. "By preventing the synapses from strengthening, we prevented the mutant mice from 'learning' the memory of cocaine, and thus prevented them from becoming addicted."Their finding provides an explanation for previous studies showing that people with substance use problems tend to have more genetic mutations associated with cadherin and cell adhesion. As studies such as this one illuminate the biochemical underpinnings of addiction, it could lead to greater confidence in predicting who is more vulnerable to drug abuse -- and enable people to act on that knowledge.Unfortunately, finding a way of augmenting cadherin as a way of resisting addiction in humans is fraught with pitfalls. In many cases, it's important to strengthen synapses -- even in the reward circuit of the brain."For normal learning, we need to be able to both weaken and strengthen synapses," Dr. Bamji says. "That plasticity allows for the pruning of some neural pathways and the formation of others, enabling the brain to adapt and to learn. Ideally, we would need to find a molecule that blocks formation of a memory of a drug-induced high, while not interfering with the ability to remember important things." | Genetically Modified | 2,017 |
February 13, 2017 | https://www.sciencedaily.com/releases/2017/02/170213131437.htm | Chemical engineers boost bacteria's productivity | MIT chemical engineers have designed a novel genetic switch that allows them to dramatically boost bacteria's production of useful chemicals by shutting down competing metabolic pathways in the cells. | In a paper appearing in the Feb. 13 issue of "We can engineer microbial cells to produce many different chemicals from simple sugars, but the cells would rather use those sugars to grow and reproduce. The challenge is to engineer a system where we get enough growth to have a productive microbial 'chemical factory' but not so much that we can't channel enough of the sugars into a pathway to make large quantities of our target molecules," says Kristala Prather, an associate professor of chemical engineering at MIT and the senior author of the study.The paper's lead author is Apoorv Gupta, an MIT graduate student. Other authors are Irene Brockman Reizman, a former MIT graduate student who is now an assistant professor at Rose-Hulman Institute of Technology; and Christopher Reisch, a former MIT postdoc who is now an assistant professor at the University of Florida.For decades, scientists have been manipulating the genes of microbes to get them to produce large quantities of products such as insulin or human growth hormone. Often this can be achieved by simply adding the gene for the desired product or ramping up expression of an existing gene.More recently, researchers have been trying to engineer microbes to generate more complex products, including pharmaceuticals and biofuels. This usually requires adding several genes encoding the enzymes that catalyze each step of the overall synthesis.In many cases, this approach also requires shutting down competing pathways that already exist in the cell. However, the timing of this shutdown is important because if the competing pathway is necessary for cell growth, turning it off limits the population size, and the bacteria won't produce enough of the desired compound.Prather's lab has previously engineered To generate large quantities of glucaric acid, the researchers had to come up with a way to shut down the glucose-breakdown pathway, allowing glucose-6-phosphate to be diverted into their alternative metabolic pathway. However, they had to carefully time the shutdown so that the cell population would be large enough to produce a substantial amount of glucaric acid. More importantly, they wanted to do so without adding any new chemicals or changing the process conditions in any way."The idea is to autonomously stop the cells from growing, midway through the production run, so that they can really focus all the available glucose sugars into glucaric acid production," Gupta says.To achieve this, the researchers took advantage of a phenomenon known as quorum sensing, which is used by many species of bacteria to coordinate gene regulation in response to their population density.In addition to adding the genes for glucaric acid production, the researchers engineered each cell to produce a protein that synthesizes a small molecule called AHL. The cells secrete this molecule into their environment, and when the concentration surrounding the cells gets to a certain point, it activates a switch that makes all of the cells stop producing an enzyme called phosphofructokinase (Pfk), which is part of the glucose breakdown pathway. With this enzyme turned off, glucose-6-phosphate accumulates and gets diverted into the alternative pathway that produces glucaric acid. By constructing a library of cells that produce AHL at different rates, the researchers could identify the best time to trigger shutdown of Pfk.Using this switch, the researchers were able to generate about 0.8 grams of glucaric acid per liter of the bacterial mixture, while cells that were engineered to produce glucaric acid but did not have the metabolic switch produced hardly any.This type of switch should also be applicable to other engineered metabolic pathways because the genetic circuit can be targeted to shut off other genes.To demonstrate this versatility, the researchers tested their approach with a metabolic pathway that produces a molecule called shikimate, which is a precursor to several different amino acids and is also an ingredient in some drugs including the influenza drug Tamiflu. They used the AHL quorum-sensing molecule to shut off an enzyme that moves shikimate further along in the amino acid synthesis pathway, allowing shikimate to build up in the cells. Without the switch, the cells could not accumulate any shikimate.The MIT team is now working on strategies to set up multiple layers of autonomous control, allowing them to shut off one pathway while also turning another one on. | Genetically Modified | 2,017 |
February 13, 2017 | https://www.sciencedaily.com/releases/2017/02/170213131238.htm | How to be a successful pest: Lessons from the green peach aphid | UK Scientists, in collaboration with groups in Europe and the US, have discovered why the green peach aphid ( | Unlike most plant-colonising insects, which have adapted to live on a small range of closely related plants, green peach aphids can colonise over four hundred plant species. Developing resistance to over 70 different pesticides, coupled with the ever changing climate affecting crop losses in the EU and UK, the pest wreaks havoc on crop yields.The green peach aphid transmits over a hundred different plant viruses and this notorious insect feeds on essential crops such as oilseed rape, sugar beet, tomato and potato, as well as wild plant species, which may serve as sources of the plant viruses. An example being the Turnip yellows virus (TuYV) and related viruses, which if left uncontrolled can reduce yields of multiple crops, such as oilseed rape and sugar beet, by up to 30%, rendering some crops unprofitable in the UK.The aphids spend winter living on host plants such as peach, apricot or plum, but in the summer months can colonise a huge range of vegetables -- from potatoes to spinach, squash, parsley and parsnip.Generally, the insect parasites that live on a certain species are genetically very well adapted to live on just that plant. Yet, research led by the Earlham Institute (EI) and the John Innes Centre (JIC), has found that the green peach aphid foregoes this specialisation for a more flexible approach involving turning gene activity 'up' or 'down' in response to different plant hosts and environments.Dr David Swarbreck, Group Leader at the Earlham Institute, said: "Our study has shed light on the genetic plasticity1 that allows the green peach aphid to survive so well on a multitude of plant species, giving us a greater insight into the survival strategies of one of the most challenging of crop pests."More intriguing about the insect's strategy is that aphids can reproduce clonally -- i.e. they produce genetically identical lineages. This allows biologists to compare individual aphids with the same genetic background and see precisely what genes are more active than others in aphids living on different plant species.By growing aphid clones on three different plant species, it was possible for the scientists to find the specific genes that were involved in colonising the different host plants. It appears that the genes responsible for helping aphids adjust to different plants are found in clusters within the genome and are rapidly increased or decreased in two days of transfer to a new host plant species.Dr Yazhou Chen, Postdoctoral Scientist at the John Innes Centre, said: "The genes rapidly turn up or down in single aphids in just two days upon transfer to a new host plant. Given that a single aphid can produce her own offspring, and a lot of it, new aphid infestations may start with just a single aphid."The team found that rapid changes in gene expression were vital for the green peach aphid's generalist lifestyle. Interfering with the expression of one particular gene family, cathepsin B, reduced aphid offspring production, but only on the host plant where the expression of these genes is increased.Thomas Mathers, Postdoctoral Scientist at the Earlham Institute, said: "Surprisingly, many of the genes involved in host adjustment arose during aphid diversification and are not specific to the green peach aphid. This suggests that it may be the ability to rapidly adjust the expression of key genes in a coordinated fashion that enables generalism, rather than the presence of an expanded genomic toolbox of genes."Professor Saskia Hogenhout at the John Innes Centre, added: "Future research is expected to reveal mechanisms involved in the amazing plasticity of the green peach aphid leading to new ways to control this notorious pest. More generally, the research will help understand how some organisms are able to adjust quickly to a broad range of environmental conditions, whereas others are pickier and go extinct more easily, research that is central given our rapidly changing environment due to, for instance, climate change." | Genetically Modified | 2,017 |
February 9, 2017 | https://www.sciencedaily.com/releases/2017/02/170209133509.htm | Bacteria fed synthetic iron-containing molecules turn into electrical generators | The bacterial world is rife with unusual talents, among them a knack for producing electricity. In the wild, "electrogenic" bacteria generate current as part of their metabolism, and now researchers at the University of California, Santa Barbara (UCSB), have found a way to confer that ability upon non-electrogenic bacteria. This technique could have applications for sustainable electricity generation and wastewater treatment, the researchers report February 9 in the journal | "The concept here is that if we just close the lid of the wastewater treatment tank and then give the bacteria an electrode, they can produce electricity while cleaning the water," says co-first author Zach Rengert, a chemistry graduate student at UCSB. "And the amount of electricity they produce will never power anything very big, but it can offset the cost of cleaning water."The bacteria that inspired this study, The researchers, under the guidance of senior author Guillermo Bazan at UCSB, built a molecule called DFSO+, which contains an iron atom at its core. To add the DFSO+ to bacteria, the researchers dissolved a small amount of the rust-colored powder into water and added that solution to bacteria. Within a few minutes, the synthetic molecule found its way into the bacteria's cell membranes and began conducting current through its iron core, providing a new pathway for the bacteria to shuttle electrons from inside to outside the cell.Because the DFSO+ molecule's shape mirrors the structure of cell membranes, it can quickly slip into the membranes and remain there comfortably for weeks. The approach might need some tweaking before being applied to long-term power generation, the researchers say, but it's an encouraging initial finding.This chemical approach to changing bacteria's capabilities will most likely be cheaper than bacteria genetically engineered to do the same job. "It's a totally different strategy for microbial electrical energy generation," says the other co-first author, Nate Kirchhofer (@natekirchhofer), formerly a grad student at UCSB and now a postdoctoral researcher at Asylum Research in Santa Barbara, CA. "Before, we were building these devices, and we were limited to optimizing them by changing reactor materials and architectures or using genetic engineering techniques."The researchers call the DFSO+ molecule a "protein prosthetic" because it is a non-protein chemical that does a protein's job. "It's sort of analogous to a prosthetic limb, where you're using a plastic limb that's not actually made out of someone else's body," says Rengert.Understanding how electrogenic bacteria consume organic fuels and use their metabolic processes to generate electric currents could lead to more efficient biological electricity-generating technology. "It's useful to have a well-defined, well-understood molecule that we can interrogate," says Kirchhofer. "We know how it's interfaced with the bacteria, so it gives us very precise electrochemical control over the bacteria. While this molecule might not be the best one that will ever exist, it's the first generation of this kind of molecule." | Genetically Modified | 2,017 |
February 9, 2017 | https://www.sciencedaily.com/releases/2017/02/170209092827.htm | In-cell molecular sieve from protein crystal | In nature, proteins are assembled into sophisticated and highly ordered structures, which enable them to execute numerous functions supporting different forms of life. The exquisite design of natural proteins prompted scientists to exploit it in synthetic biology to engineer molecules that can self-assemble into nanoparticles with desired structure and that may be used for various purposes such as gas storage, enzyme catalysis, intracellular drug delivery, etc. | Cytoplasmic polyhedrosis viruses (cypoviruses) infecting insects are embedded in protein crystals called polyhedra which shield the virus from damage. The structure of polyhedra crystals (PhCs) suggests that they can serve as robust containers which can incorporate and protect foreign molecules from degradation, ensuring their compositional and functional stability.Extreme stability of polyhedra under harsh conditions is provided by dense packing of polyhedrin monomers in crystals with solvent channels of very low porosity, which, however, limits the incorporation of foreign particles. Research group led by Satoshi Abe and Takafumi Ueno at Tokyo Institute of Technology hypothesized that if a porous framework inside PhCs is extended without compromising crystal stability, PhCs can be used for accumulation and storage of exogenous molecules in living cells. As in natural PhCs, polyhedrin monomers form a trimer, the scientists assumed that if amino acid residues at the contact interface of each trimer are deleted, the porosity of the resulting crystals would be increased. To achieve this goal, they genetically engineered polyhedrin monomers, which were then expressed and self-assembled in Spodoptera frugiperda IPLB-Sf21AE, the larva of an armyworm moth, infected with baculovirus. The mutant PhCs maintained crystal lattice of the wild-type PhC but had significantly extended porosity due to the deletion of amino acid residues with the rearrangement of intra- and intermolecular hydrogen bonds. As a result, the engineered crystals could adsorb 2-4 times more exogenous molecules (fluorescent dyes) compared to the wild type PhC, with up to 5,000-fold condensation of the dyes from the 10 uM solution.As a next step, the scientists examined the performance of the mutant crystals in living insect cells. PhCs showed high stability in the intracellular environment. Most importantly, the mutant crystals could accumulate and retain the dyes in live cells, while the natural crystals could not.Rationale crystal design used by scientists at Tokyo Institute of Technology provides a powerful tool for structural manipulation of self-assembled protein crystals to obtain porous nanomaterials with regulated adsorption properties. The engineered porous PhCs can be used as protein containers for in vivo crystal structure analysis of the cellular molecules and bioorthogonal chemistry in various types of living cells.Since tiny crystals with only a few microns size were obtained, the structure analyses were performed at beamlines BL32XU and BL41XU at SPring-8, a large synchrotron radiation facility which delivers the most powerful synchrotron radiation. The high-resolution structures were rapidly analyzed with the help of an automated data collection system developed in RIKEN. | Genetically Modified | 2,017 |
February 8, 2017 | https://www.sciencedaily.com/releases/2017/02/170208094210.htm | Rethink needed to save critically endangered black rhinoceros | A new strategy of conservation must be adopted if the black rhinoceros is to be saved from extinction, concludes a study involving scientists from Cardiff University. | An international team of researchers compared, for the first time, the genes of all living and extinct black rhinoceros populations and found a massive decline in genetic diversity, with 44 of 64 genetic lineages no longer existing. The new data suggest that the future is bleak for the black rhinoceros unless the conservation of genetically distinct populations is made a priority.Professor Mike Bruford from Cardiff University's School of Biosciences said: "Our findings reveal that hunting and habitat loss has reduced the evolutionary potential of the black rhinoceros dramatically over the last 200 years. The magnitude of this loss in genetic diversity really did surprise us -- we did not expect it to be so profound."The decline in the species' genetic diversity threatens to compromise its potential to adapt in the future as the climate and African landscape changes due to increased pressure from man. The new genetic data we have collected will allow us to identify populations of priority for conservation, giving us a better chance of preventing the species from total extinction."The research team used DNA extracted from a combination of tissue and fecal samples from wild animals, and skin from museum specimens. They sequenced DNA from maternal mitochondrial genome and used classical DNA profiling to measure genetic diversity in past and present populations and compared the profiles and sequences of animals in different regions of Africa. Their next step is to sequence the black rhino genome to see how the loss of genetic diversity is likely to affect populations across all of its genes, vital information given the current poaching epidemic and the fact that some populations are being targeted more than others.The black rhinoceros has already been hunted to extinction in many parts of Africa and now survives in only five countries: South Africa, Namibia, Kenya, Zimbabwe and Tanzania.Renewed poaching has threatened this recovery as rhinoceros horn has attained an unprecedented and steadily rising value.The research 'Extinctions, genetic erosion and conservation options for the black rhinoceros' is published in This project was funded by the International Rhino Foundation. | Genetically Modified | 2,017 |
February 1, 2017 | https://www.sciencedaily.com/releases/2017/02/170201121527.htm | Genetically modified insects could disrupt international food trade | 'There's a fly in my soup.' This statement conjures up the image of a dead fly in a bowl of soup rather than a genetically modified insect being served up with organic vegetables. However, this is not a totally unrealistic scenario as experimental releases of genetically modified insects have been approved by US regulators in 2014 very near farming areas. The question is whether fruit and vegetables exported from the USA to Europe and China can be sold under the "organic" label if genetically modified insects have developed on them. Guy Reeves from the Max Planck Institute for Evolutionary Biology in Plön, Germany, and Martin Phillipson Dean of Law at the University of Saskatchewan, Canada, are drawing attention to this problem. In their view, clarifying statements on the part of US regulators is required to ensure that producers of organic commodities do not have to fear for their reputation. | All around the world for the last 50 years, males sterilised by transient exposure to radiation have been used to successfully control a wide range of insect species (e.g. screw worm and medfly). While these males can still mate, the resulting eggs are not viable. A new elaboration of this technique that utilises genetically modified males that only produce sons has recently been approved for open field-testing in the USA. In both approaches where sufficient males are released over several generations the size of the wild female populations will decline and the pest population will gradually be reduced or become locally extinct.The following applications for mass open release of genetically modified insects for agricultural pest control have been submitted:The permit allowed for the of release genetically modified diamondback moths 72 times per year until the end of March 2017. With releases of up to 100,000 moths per week on cabbage or broccoli fields totalling 40,500 square metres.The big advantage of releasing sterile insects is that pests can be controlled without the need to spray chemical insecticides into the environment. This is true for both the conventional irradiation approach and the new genetically modified approach. However, if the use of genetically modified insects in agriculture is to become a widespread solution for pest control, the implications stemming from the fact that genetically modified insects are intended to fly between farms needs to be adequately considered. Realistically this must be done in the context of the regulations on the presence of genetically modified contaminants in food that have developed over the past 30 years around the world.The release of genetically modified insects has potential consequences for organic farmers, which are a particularly sensitive group in this respect. "There are some realistic circumstances where the mass release of flying genetically modified insects could harm organic farmers and erode consumer confidence in their products. Unfortunately, we can find little evidence of efforts to reduce this risk or even discuss the issue," explains Reeves from the Max Planck Institute in Plön.Using legal case studies around the world (Australia, China, Canada, EU and the USA) Reeves and Phillipson establish that any detected or conceivably perceived contamination of crops imported into countries that have not approved its presence is likely to be met with import bans, disrupting international trade. The situation for crop products internationally certified as "100 percent organic" has additional levels of complexity. These include the costs of any negative perceptions of involvement in this technology by organic consumers and the potential loss of organic certification by farms located near releases.The article also focuses on the situation of a hypothetical certified organic spinach farmer located near a widely reported approved release of genetically modified diamondback moths in New York State (USA). Currently, there is no obligation to inform local farmers of mass releases, which makes it difficult for them to plan or mitigate risks. This is even the case within the three kilometre area indicated by a published experimental study that may be appropriate for diamondback moth control programs.In addition, a letter from the European Commission Health and Consumers Directorate-General indicates that inadvertent presence of genetically modified insects imported into the EU would be unapproved and that it is the responsibility of Member States to prevent this occurring. In order for genetically modified insects to be used successfully (potentially on organic farms), it is essential that all of the affected groups be involved in the development process and have access to regularly updated information. "While the introduction of driverless cars has the potential to bring a wide range of benefits it would be misguided to introduce them without making it clear that cyclists will not be knocked over by them. Likewise releasing flying genetically modified insects without considering the likely impact on sensitive groups of farmers is unwise and unnecessary," says Reeves. | Genetically Modified | 2,017 |
January 23, 2017 | https://www.sciencedaily.com/releases/2017/01/170123115157.htm | Switching off the brain | Switching off specific brain regions in a laboratory animal is an important type of experiment used to better understand how the brain works. A study published in | Neurons (brain cells) process information and control behaviour by sending signals to other neurons, hormone-releasing cells and muscles. A fuller understanding of the neuronal control of behaviour would accelerate the development of therapies for neurological and psychiatric disorders.One of the ways researchers have tried to understand the neuronal control of behaviour is with optogenetics, a technique that uses light-sensitive proteins to control neuronal activity in living tissue. In optogenetics, neurons are genetically modified to express light-sensitive ion channels (proteins that conduct electricity), such that light exposure may be used to activate or inhibit electrical activity."There are many useful optogenetic tools to stimulate neural activity but not as many effective inhibitors," explained Assistant Professor Adam Claridge-Chang, who led the research at Duke-NUS Medical School (Duke-NUS) and A*STAR's Institute of Molecular and Cell Biology (IMCB).Being able to inhibit neural circuits provides researchers the ability to determine the importance of a particular circuit in defining behaviour. In view of that, Asst Prof Claridge-Chang with Dr Farhan Mohammad and other colleagues explored the use of anion channelrhodopsins (ACRs) from an alga species (Guillardia theta) to inhibit neural activity.In reading the paper that first described the ACRs, Dr Mohammad realized that ACRs conducted more current compared to other tools. "They are rapidly responsive, require low light intensities for actuation, so they seemed ideal for inhibiting brain activity in fly behaviour experiments," said Dr Mohammad, a Research Fellow in the Claridge-Chang group.The group genetically modified flies to express ACRs, and exposed these animals to light of different colours and intensities. In one of the experiments, ACR actuation paralysed climbing flies, causing them to fall abruptly. In another, illumination of ACRs in the animals' sweet-sensing cells resulted in flies that avoided green light, as though they were avoiding the silencing of a sweet taste. At the cellular level, light actuation of ACRs produced dramatic reductions in electrical activity.The work done at Duke-NUS and A*STAR's IMCB indicated that ACRs are highly effective optogenetic tools for the inhibition of behavioural circuits."Since they are as powerful as existing methods, but much faster and easier to use, there has been huge interest from the "Understanding any system is greatly aided by being able to remove components from that system and examine the resulting behaviour," explained Asst Prof Claridge-Chang. "The ACRs are the seventh generation of optogenetic inhibitors, but the first that robustly inhibit | Genetically Modified | 2,017 |
January 19, 2017 | https://www.sciencedaily.com/releases/2017/01/170119163343.htm | Research findings could help prevent crop-killing pathogen from coming to U.S. | New findings by University of Florida Institute of Food and Agricultural Sciences researchers could help prevent more genetic strains of the potato- and tomato-killing late-blight pathogen from entering the United States. | These findings may provide further evidence to help researchers solve the $6 billion-a-year disease that continues to evolve and torment potato and tomato growers around the world.Erica Goss, a UF/IFAS assistant professor of plant pathology, who published a study in 2014 showing Toluca, Mexico as the origin of the late-blight pathogen, has now discovered the pathogen in other parts of Mexico. Goss and her team also found that each strain varies genetically.Goss and her research team analyzed the genes of potato late-blight pathogens and found the pathogen in western Mexico (Michoacan, Mexico) differs genetically from the one in central (Toluca) and eastern Mexico (Tlaxcala and Puebla)."This genetic difference allowed us to track the potential source of strains that show up in the U.S., just like genetic analysis of an American person of European ancestry would tell you if their family was more likely to have originated from western Europe or eastern Europe," Goss said.This finding could be crucial to helping feed more people, said Goss, who also is affiliated with the UF Emerging Pathogens Institute."What our study shows is that there is more potential trouble that could make its way here, replace the existing genetic types of the pathogen in the U.S., and affect disease control," she said.To increase U.S. food security, scientists should study the genetic variation in Mexico and try to track how the strains are coming to America so they can prevent future introductions, Goss said."By doing more extensive sampling across Mexico, we could do more to pinpoint the source of strains that are showing up in the U.S.," she said.In the 1840s, the late-blight pathogen caused the Irish Potato Famine, which killed most of that country's potatoes. Today, it costs Florida tomato farmers millions each year in lost yield, unmarketable crop and control expenses.A late-blight pandemic in 2009 made the pathogen a household term in much of the eastern U.S. It made its way to the Northeast via tomatoes in big-box retailers.After planting the tomatoes, many home gardeners and organic producers lost most, if not all, of their crop, Goss said.The study is published in the journal | Genetically Modified | 2,017 |
January 16, 2017 | https://www.sciencedaily.com/releases/2017/01/170116160534.htm | New tools will drive greater understanding of wheat genes | Howard Hughes Medical Institute scientists have developed a much-needed genetic resource that will greatly accelerate the study of gene functions in wheat. The resource, a collection of wheat seeds with more than 10 million sequenced and carefully catalogued genetic mutations, is freely available to wheat breeders and researchers, and is already aiding in the development of wheat plants with improved traits. | Jorge Dubcovsky, a Howard Hughes Medical Institute-Gordon and Betty Moore Foundation investigator at the University of California, Davis, and his collaborator Cristobal Uauy, a crop geneticist at the John Innes Institute in the United Kingdom, led the development of the new genetic tool, which was reported in the Wheat is a vital crop, supplying 20 percent of the calories consumed by humans worldwide. To maintain food security, wheat breeders are working to develop plants that offer more nutritional value, have greater yields, and can thrive in a changing climate. A key genetic feature makes the plant difficult to study and manipulate, however. Like many plants, wheat is polyploid, meaning it has multiple copies of its genome in every cell: Pasta wheat has two copies of every gene, and bread wheat has three.To study the function of an individual gene, researchers typically mutate or eliminate that gene to find out what happens -- an approach known as reverse genetics. But in a polyploid organism such as wheat, mutations in individual genes often have no apparent effect, because additional copies of the mutated gene compensate for the loss. Researchers must cross plants with mutations in different copies of the gene several times to obtain a generation of plants in which the gene's function is lost. The gene copies also hide natural variation in the wheat genome that could create opportunities to selectively breed plants with useful traits.Wheat researchers knew that a comprehensive collection of wheat lines with defined genetic mutations would transform the way they worked. "We didn't have any reverse genetics resource for wheat, and it was absolutely necessary for us to study gene function," Dubcovsky says. But because of the complexity of the wheat genome, developing that resource was a massive undertaking.Dubcovsky and his colleagues chemically induced random genetic mutations in thousands of wheat seeds and began developing and characterizing their collection of wheat mutant lines more than five years ago. To make it possible to analyze the DNA of all of the lines, the researchers developed an approach that let them focus on the small fraction of the genome that encodes proteins. Focusing on this small portion of each plant's genome, the team sequenced 400 billion bases of DNA using sophisticated sequencing technology to analyze the plants that grew from the mutated seeds -- a total of 2,735 mutant lines. Seeds from each plant line were increased and saved for distribution.Because wheat's polyploidy enables it to tolerate many mutations without impairing growth, the researchers were able to develop lines with a high density of genetic mutations -- thousands were detected in every plant. More than 90 percent of the plants' genes are disrupted by the ten million mutations catalogued in the collection, making it a powerful resource for studying the function of nearly any wheat gene. | Genetically Modified | 2,017 |
January 12, 2017 | https://www.sciencedaily.com/releases/2017/01/170112141301.htm | Genetically engineered mosquitoes resist dengue fever virus | After decades of research and countless control attempts, dengue fever -- a mosquito-borne viral disease -- continues to infect an estimated 390 million people around the world each year. Now, researchers have reported in | When a mosquito bites someone infected with DENV, the virus needs to complete its lifecycle in the mosquito's gut, eventually infecting its salivary glands, before it can infect another person. Previous studies have shown that mosquitoes rely on a molecular pathway dubbed JAK/STAT to try to fight DENV infection and stop this cycle. Proteins known as Dome and Hop are involved in turning on the JAK/STAT when the mosquito is infected with DENV.In the new work, George Dimopoulos, of Johns Hopkins University, and colleagues genetically engineered mosquitoes with engineered versions of Dome or Hop that were then infected with DENV had 78.18% (Dome) and 83.63% (Hop) fewer copies of the virus in their guts, as well as significantly less virus in their salivary glands. mosquitoes with the altered genes had normal lifespans, but produced fewer eggs than normal mosquitoes. When the researchers repeated the experiments with Zika virus and chikungunya virus, no impact was seen on infection, suggesting that the importance of the JAK/STAT pathway in the fatbody tissue is unique to DENV."It may be possible to achieve improved or total resistance to dengue and other viruses by expressing additional transgenes in multiple tissues that block the virus through different mechanisms," the researchers write. "Recently developed powerful mosquito gene-drive systems, that are under development, are likely to make it possible to spread pathogen resistance in mosquito populations in a self-propagating fashion, even at a certain fitness cost." | Genetically Modified | 2,017 |
January 12, 2017 | https://www.sciencedaily.com/releases/2017/01/170112141146.htm | Researchers create mosquito resistant to dengue virus | Researchers from the Johns Hopkins Bloomberg School of Public Health have genetically modified mosquitoes to resist infection from dengue virus, a virus that sickens an estimated 96 million people globally each year and kills more than 20,000, mostly children. | The research, published Jan. 12 in "If you can replace a natural population of dengue-transmitting mosquitoes with genetically modified ones that are resistant to virus, you can stop disease transmission," says study leader George Dimopoulos, PhD, a professor in the Department of Molecular Microbiology and Immunology and a member of the Johns Hopkins Malaria Research Institute. "This is a first step toward that goal."While the new mosquitoes significantly suppressed dengue virus infection they did not show any resistance to Zika or chikungunya, two other viruses carried by Mosquitoes acquire viruses by feeding on the blood of humans who are sickened with them. Once the mosquitoes are infected, they bite other healthy humans and pass the disease along to them. Many efforts are underway to figure out how to break that cycle, and most scientists agree that the use of multiple methods will be required to eliminate dengue and other mosquito-borne diseases.Researchers say that The genetic modification resulted in fewer mosquitoes becoming infected, and most of those that did had very low levels of dengue virus in their salivary glands, the location from which it gets transmitted to humans. These experiments, however, didn't lower the level of virus in all mosquitoes to zero, something that puzzled the scientists. They say more research is needed to understand whether this level of virus suppression would be enough to halt disease transmission, and they are working on other experiments to see if they can produce antiviral factors in the gut, which could assist in inducing a stronger immune response and possibly confer resistance to the other viruses.The researchers found that the dengue-resistant mosquitoes live as long as the wild mosquitoes, though they do produce fewer eggs, most likely because the same mechanism involved in dialing up the immune system to fight dengue also plays a role in egg production."It's likely if we turn this on in the gut we could have a much stronger effect, without compromising egg production," Dimopoulos says.Once genetically modified mosquitoes resistant to dengue are developed, scientists would test them in large field cages to see how they compete with wild mosquitoes in very controlled experiments.The best way to ensure that the genetically modified mosquitoes become the dominant type is for researchers to add something known as a "gene drive" to the new mosquitoes. This essentially makes them genetically superior mosquitoes by ensuring that all offspring of wild- type and genetically modified mosquitoes will be disease resistant."In this way, you could convert a disease-transmitting mosquito population to one that does not transmit disease," Dimopoulos says.Scientists acknowledge there are concerns with the release of genetically modified mosquitoes in the environment since they can't be recaptured. They are there to stay."This is why extensive lab and semi-field studies are required to get it right," he says. If the scientists can get this to work, however, it could become a very effective way of controlling disease. It could be done without people having to actively participate. They would get long-lasting protection without having to take medication, get vaccinated or use bed nets or repellants.Dimopoulos and other researchers are working on similar models in The entire process of developing and introducing disease-resistant mosquitoes into the wild could take a decade or more. | Genetically Modified | 2,017 |
January 11, 2017 | https://www.sciencedaily.com/releases/2017/01/170111151845.htm | Genetic opposites attract when chimpanzees choose a mate | When it comes to hookups in the animal world, casual sex is common among chimpanzees. In our closest animal relatives both males and females mate with multiple partners. But when taking the plunge into parenthood, they're more selective than it seems. | A study appearing online Jan. 11 in the journal Many animals avoid breeding with parents, siblings and other close relatives, said first author Kara Walker, a postdoctoral associate in evolutionary anthropology at Duke University. But chimpanzees are unusual in that even among nonrelatives and virtual strangers they can tell genetically similar mates from more distant ones.The researchers aren't sure yet exactly how they discriminate, but it might be a best guess based on appearance, smell or sound, said senior author Anne Pusey, professor of evolutionary anthropology at Duke.Researchers took DNA samples from the feces of roughly 150 adult chimpanzees in Gombe National Park, Tanzania, and analyzed eight to 11 variable sites across the genome. From these, they were able to estimate the genetic similarity between every possible male-female pair.In chimpanzees, as in other animals, only some sexual encounters lead to offspring. When the researchers compared pairs that produced infants with those that didn't, they found that females conceived with sires that were less similar to them than the average male.Chimps are somehow able to distinguish degrees of genetic similarity among unfamiliar mates many steps removed from them in their family tree, the study shows.In Gombe National Park, some females stay in the same group for life, but most move out as they reach adolescence, leaving their fathers and brothers behind to reproduce in a new group. These immigrant females, which have few or no male relatives in their community, showed even stronger preference for genetically dissimilar mates than the native females did.Part of what's driving their mate choices, the researchers say, is inbreeding depression, which is when offspring inherit the same harmful version of a gene from both parents and genetic vulnerabilities that are normally masked become active.Conception between parents and offspring or between siblings is rare in chimpanzees, but studies suggest that when it occurs, the infants that result are less likely to survive to maturity than their outbred counterparts.Unlike humans, chimpanzees can't take genetic tests to help them find their perfect match.Now the researchers are trying to figure out how chimpanzees recognize and favor mates whose DNA is more different from theirs, even among unfamiliar partners. The animals do more than simply avoid mates they grew up with and are therefore likely to be related to, the study shows.In addition to whatever means they are using to distinguish relatedness, they could also rely on timing, being pickier about their sexual partners during the part of a female's cycle when she is most likely to conceive. Processes that take place after mating may also play a role, such as a female unconsciously choosing some males' sperm over others, or influencing the fertilized egg's implanting or the fate of the embryo, Walker said. | Genetically Modified | 2,017 |
January 11, 2017 | https://www.sciencedaily.com/releases/2017/01/170111151834.htm | Strep spreads by harnessing immune defenses of those infected | The bacteria that cause most cases of pneumonia worldwide secrete a toxin that helps them jump from one body to the next -- with help from the hosts' immune defenses. This is the finding of a study led by researchers from NYU Langone Medical Center and published online January 11 in | The study explains survival "strategies" used by the bacteria Streptococcus pneumoniae, or pneumococcus, which causes millions of infections each year. Most often infecting the nasal cavity, sinuses and lungs, these infections can be deadly in patients with weak immune systems, especially young children and the elderly.In the current study, conducted in mice, researchers determined that Researchers argue that these bacteria have evolved to take advantage of being expelled, riding the secretions out of the body and on to their next host. Researchers found that "Factors that allow for the host-to-host transmission of disease-causing bacteria have not been thoroughly investigated by the field as a means of prevention," says Jeffrey Weiser, MD, chair of the Department of Microbiology at NYU Langone. "Our findings provide evidence of the tool used by these bacteria to spread, which promises to guide the design of new kinds of countermeasures."Bacteria trying to survive on the surfaces of human airways must overcome two challenges not encountered by organisms that infect the gut. Firstly, healthy hosts do not regularly expel contents of their airways the way they do from their guts, which frees microbes to travel to their next host. Secondly, airways do not offer the same regular food supply to bacteria as the gut.By emitting the pneumolysin toxin, Framing the current results is past work that explains how The current study authors modified a mouse model of bacterial transmission recently developed by another lab to study for the first time pneumococcal transmission when the flu is absent.The authors show that inflammation induced by pneumococcal colonization alone, particularly in response to pneumolysin, was capable of causing bacterial shedding needed for transmission between hosts.The study results also answered a long-held question in the field about why bacteria that depend on their relationship with their host give off such a destructive toxin. Why not live on over time in relative "peace," allowing your host to feed you? The answer, say the researchers, is that the benefit to the organism of a higher rate of transmission compensates for the damaging effects of the toxin on the host."Our study results argue that toxins made by bacteria are central mediators of transmission between hosts, which makes them attractive as a potential ingredient in vaccines, to which they could be added specifically to block transmission," says Weiser. "There are precedents in using disarmed bacterial toxins, or toxoids, as vaccine ingredients, as with existing vaccines against diphtheria, tetanus and pertussis." | Genetically Modified | 2,017 |
January 11, 2017 | https://www.sciencedaily.com/releases/2017/01/170111093430.htm | 'Gene-silencing' technique is a game-changer for crop protection | Researchers at the University of Surrey and University of Queensland have developed a revolutionary new crop protection technique which offers an environmentally-friendly alternative to genetically-modified crops and chemical pesticides. | The breakthrough research, published in The researchers have found that by combining clay nanoparticles with designer 'RNAs' (molecules with essential roles in gene biology), it is possible to silence certain genes within plants. The spray they have developed -- known as BioClay -- has been shown to give plants virus protection for at least 20 days following a single application. When sprayed with BioClay, the plant 'thinks' it is being attacked by a disease or pest insect and responds by protecting itself.The latest research overcomes the instability of 'naked' RNAs sprayed on plants, which has previously prevented them from being used effectively for virus protection. By loading the agents on to clay nanoparticles, they do not wash off, enabling them to be released over an extended period of time before degrading.The BioClay technology, which is based on nanoparticles used in the development of human drug treatments, has a number of advantages over existing chemical-based pesticides. Since BioClay is non-toxic and degradable, there is less risk to the environment and human health. It can also be used in a highly targeted way to protect crops against specific pathogens.Professor G.Q. Max Lu, President and Vice-Chancellor of the University of Surrey and co-author of the research paper, said: "This is one of the best examples of nanoparticles being effective for biological molecular delivery with a controlled release rate for combating diseases in plants or animals. The same nanoparticle technology invented and patented in my laboratory at the University of Queensland was used for effective targeted drug delivery. It was licensed to an Oxford-based pharmaceutical company and is now being commercialised for drug development.""I am very pleased to see the exciting results of this project and the publication of our research in the | Genetically Modified | 2,017 |
January 10, 2017 | https://www.sciencedaily.com/releases/2017/01/170110153937.htm | Eastern Russian plant collection could improve cold hardiness in miscanthus | Winters in eastern Russia are intensely cold, with air temperatures regularly reaching -30 degrees Fahrenheit in some locations. It is a seemingly inhospitable climate, but native plants have found ways to thrive there. University of Illinois plant geneticist Erik Sacks suspected one of these plants may hold the key to breeding cold-tolerant food and biomass crops. To find out, the modern-day botanical explorer set off across eastern Russia with colleagues from the N. I. Vavilov All-Russian Institute of Plant Genetic Resources (VIR) to collect specimens of the perennial grass | "Miscanthus is part of a tribe of grasses, the Andropogoneae, that includes sorghum, sugarcane, and corn," Sacks explains. "Because it is found so far north, this population of Sacks and his colleagues collected miscanthus from 47 locations across eastern Russia, including at least one location where Sacks wasn't expecting to find it; in that case, he used his bare hands to pull it from the ground. Live rhizome fragments were sent back to U of I to be genetically analyzed and to USDA's National Plant Germplasm System to be maintained and distributed to scientists worldwide for use in breeding and research. Samples were also provided to the VIR genebank.While in the field, Sacks' team also measured traits that can be used to predict biomass production: height, number of stems, and stem diameter. When plant geneticist and the report's lead author Lindsay Clark analyzed the plant material at U of I, she found several genetic markers associated with the traits measured in the field."Normally, breeders have to grow up plants from these collections and evaluate them in a replicated field trial," Sacks says. "That's very expensive and takes a lot of time. In the future when people go collecting, if there are heritable traits of value that can be measured quickly in the field, our results suggest it may be worthwhile to do so. It may not be as perfect as a replicated field trial in multiple sites, but it gives you a place to start."The analysis also showed that plants in the collection were genetically diverse, a fact that could potentially be exploited by breeders to express desirable traits in new miscanthus varieties or to add greater cold hardiness to its relatives, sugarcane and maize.Furthermore, most of the plants were diploid -- with each cell containing two copies of each chromosome -- but 2 percent were tetraploid, with four copies. The most widely grown miscanthus variety in the United States, "We have this one genotype of "If we used the tetraploids from this collection to make new sterile The research team has a lot more work to do before new miscanthus varieties are commercially available, but Sacks sees the exploration as a success. "Genetic diversity is the basis for all crop improvement, and germplasm collections play a key role. Without them, plant breeders can't make great improvements in our crops in terms of yield, hardiness, and a variety of different abiotic and biotic stresses," he says.The article, "Ecological characteristics and | Genetically Modified | 2,017 |
January 10, 2017 | https://www.sciencedaily.com/releases/2017/01/170110151408.htm | For viral predators of bacteria, sensitivity can be contagious | Bacteriophages (phages) are probably the most abundant entities in nature, often exceeding bacterial densities by an order of magnitude. As viral predators of bacteria, phages have a major impact on bacterial communities by reducing some bacteria and enabling others to flourish. Phages also occasionally package host DNA and deliver it to other bacteria, in a process known as horizontal gene transfer (HGT). | The biology of phage infection has been extensively studied since the beginning of the 20th century. However, the fate of phages in complex bacterial communities resembling their natural ecosystem has not been studied at the cellular level. To investigate the biology of phage infection in complex bacterial communities, researchers followed phage dynamics in communities harboring phage-resistant (R) and phage-sensitive (S) bacteria, a common scenario in nature.Now, in new research in the January 12 edition of The researchers show how phage-sensitive bacteria harboring phage receptor can deliver the receptor to nearby phage-resistant cells that lack the phage receptor, via a molecular transfer they call "acquisition of sensitivity" (ASEN). This process involves a molecular exchange driven by membrane vesicles (MVs), in which phage-resistant cells transiently gain phage attachment molecules released from neighboring phage-sensitive cells. By exploiting this novel delivery system, phages can invade bacteria lacking their receptor.The researchers further posit that this mechanism enables phages to expand their host range and deliver DNA into new species, thus facilitating the attachment of phages to non-host species, providing an as-yet unexplored route for horizontal gene transfer (HGT)."In the present study, we show for the first time how bacteria entirely resistant to a given phage become susceptible upon co-incubation with sensitive bacteria. Phage invasion into resistant cells could have a major impact on transfer of antibiotic resistance and virulence genes among bacteria. This aspect should be carefully considered when employing phage therapy, as phage infection of a given species may result in gene transmission into neighboring bacteria resistant to the phage," said Prof. Sigal Ben-Yehuda, who led the research at the Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada, in the Hebrew University's Faculty of Medicine."Our work indicates that, similarly to the remarkable arsenal of entry and spreading strategies employed by viruses, phages utilize alternative, as yet unidentified spreading mechanisms, which could expedite the infection process and promote phage spread within cells of the same and different species," said the PhD student Elhanan Tzipilevich, who carried out this research. | Genetically Modified | 2,017 |
January 9, 2017 | https://www.sciencedaily.com/releases/2017/01/170109113803.htm | For chemicals, mega is out and bio is in | Ramon Gonzalez sees flares burning methane from the stacks above Houston's refineries and thinks, "What a waste." He believes that methane represents an opportunity for biomanufacturing that should not be missed. | The Rice University professor and director of its new Advanced Biomanufacturing Initiative, aka iBIO, already knows what an entire sector of the chemical manufacturing industry is beginning to realize: Waste methane can and should be turned into profit.Given the steady advance of biomanufacturing -- the use of wild-type or genetically modified bacteria to turn carbon-rich methane and other substances into valuable chemicals -- it should be possible to produce chemicals on a smaller, more environmentally friendly scale, he said. But it would require a shift from current thinking that economic viability can come only from the economies of unit scale afforded by large facilities.Biomanufacturing's promise is the subject of a perspective paper in Gonzalez, who specializes in the creation of genetically engineered bacteria for biotechnology, has taken on the role of a seer informed both by his own research and by his years as a program director at the government's Advanced Research Projects Agency-Energy, where he sharpened his eye for emerging technologies.In the online paper, also summarized in the current print version of Science, the authors point out that advances in metabolic engineering, genomics and industrial process design have pushed industrial biomanufacturing closer than ever to widespread adoption. They argue it could and should go much further."Biotech in general has four branches of applications: Medical, agricultural, environmental and industrial, the one in which we primarily work," said Gonzalez, a professor of chemical and biomolecular engineering and of bioengineering based at Rice's BioScience Research Collaborative. "The industrial side aims at generating molecules that are produced these days from many feedstocks, including oil and natural gas."What has not been explored much in this space is what biology brings to the table, regardless of whether you use starting materials that are renewable or not."Renewable feedstocks include corn and lignocellulosic biomass used to produce ethanol and other molecules. Nonrenewables include oil and gas used to produce thousands of chemicals required by industry, typically at immense facilities that offer economies of scale. Gonzalez said small-scale biomanufacturing tends to be associated primarily with renewable sources, but he and his team don't necessarily see that as the only use of the growing technology."You don't need to go big," he said. "This is an area that almost nobody explores. Actually, companies are doing the contrary: They are saying, 'Let's go big with biology' and forcing it to do things that are not a natural fit for biomanufacturing. That's not necessarily what biology is good at."He said that among the findings, the most surprising may be that waste methane burned off in 2014 alone could have been transformed via biomanufacturing into seven important organic chemicals -- methanol, ethylene, propylene, butadiene, xylene, benzene and toluene -- in amounts sufficient to meet 100 percent of industry's needs that year."Between flared methane, waste-treatment facilities situated near population centers and agricultural facilities around the country, we have a lot of feedstock," Gonzalez said. "You might say these are little things, but when you add them up -- and we have run that number -- we find we can produce most of the chemicals that we need today."Few if any of these feedstocks are easily accessible to megafacilities that require the efficient delivery of large quantities of mostly fossil-based raw materials, he said. In contrast, biomanufacturing facilities operate at much smaller scales and require quantities of feedstocks that match the output of distributed (and often wasted) methane-generating sites.A distribution of small factories puts them closer not only to feedstocks but also to point of need. That would also facilitate faster innovation and a more rapid response to the needs of the market, Gonzalez said. The lower cost of entry would allow for a more diverse group of technology players, he said.He noted as an example that small, strategically placed bioconversion facilities have increased the nation's ethanol output tenfold over the past two decades.The researchers pointed out that environmental, geopolitical and economic factors are already pushing manufacturers to look at smaller, better-distributed solutions to pressing needs. The science of programming bacteria like fast-growing Escherichia coli to make chemicals using genome-editing techniques like CRISPR/Cas-9 is rapidly catching up to the demand, Gonzalez said."Do you need to produce millions of tons of chemicals?" he asked. "How are you going to do that if you have a small plant and still make an impact? Well, if you have hundreds or thousands of small plants, of course you're going to make an impact."You can leverage an 'economies of unit number' model, which can be defined as a shift from a small number of high-capacity units or facilities to a large number of units or facilities operating at a smaller scale. The good news is that, as we demonstrate in this paper, industrial biomanufacturing can both support and benefit from economies of unit number."Gonzalez said developing nations may benefit greatly from decentralized biomanufacturing, and then he looked even farther afield."The atmosphere of Mars is 95 percent carbon dioxide, and to plant a flag there, you really have to start with that and solar energy, whether you like it or not," he said. "And you can do it with something like I'm describing here."You don't need to bring a chemical plant to Mars. You could bring microbes in a vial that replicate and grow and produce what you need from the abundant carbon already there." | Genetically Modified | 2,017 |
January 4, 2017 | https://www.sciencedaily.com/releases/2017/01/170104192311.htm | Scientists learn how to ramp up microbes' ability to make memories | Some microbes can form memories -- although, inconveniently for scientists who study the process, they don't do it very often. | Rockefeller University researchers and their colleagues at the University of California, Berkeley, have found a way to make bacteria encode memories much more frequently. Their discovery was described December 22 in "CRISPR, the adaptive immune system found within many bacteria, remembers viruses by storing snippets of their DNA. But in nature, these recording events happen only rarely," says senior author Luciano Marraffini, head of the Laboratory of Bacteriology."We have identified a single mutation that causes bacterial cells to acquire genetic memories of viruses 100 times more frequently than they do naturally," he adds. "This mutation provides a powerful tool for experiments in our lab and elsewhere, and could facilitate the creation of DNA-based data storage devices."If a virus that a bacterium's CRISPR system has recorded shows up again, an enzyme known as Cas9 is dispatched to destroy it. The system's precision has already made it an important tool for editing genomes, and scientists are looking toward other potential applications.For the current study, the team randomly introduced mutations into the gene for Cas9 and found that one of them prompts bacteria to acquire genetic memories more readily. Under normal conditions, if researchers expose 100,000 bacterial cells to the same potentially deadly virus, only one will typically acquire a DNA snippet that could enable it to survive a future attack. In cells engineered to carry this new mutation, the ratio increases to one in 1,000.The mutation quickly became useful to nearly all of the projects going on in Marraffini's lab. Working with microbes whose genetic memories have been enhanced this way, the scientists are able to generate much more data about various aspects of CRISPR.There may be other applications, though some are far off on the horizon. Some synthetic biologists -- scientists who design and build novel biological machines -- think a CRISPR-like system could be adapted to capture information about the activity of neurons, how cells respond to environmental stimuli, or the trajectory of metastasizing cancer cells. Although many hurdles remain for the development of a CRISPR-based recording system, this mutation could potentially make it more realistic, the researchers say.The discovery also raises a question: If this mutation makes bacteria more capable of defending themselves, why haven't they evolved to carry it naturally? "There is a trade-off with CRISPR," explains first author Robert Heler, a graduate student in the lab. Although the system defends cells, it can sometimes misfire by acquiring DNA snippets from its host rather than from an invading virus, leading the cell to kill itself. "Unless they are beseiged by an exceedingly high volume of viruses that require a potent CRISPR-Cas defense, microbes without the mutation have a survival advantage because they are less prone to this type of suicide," Heler says. | Genetically Modified | 2,017 |
December 1, 2016 | https://www.sciencedaily.com/releases/2016/12/161201165922.htm | Modifying a live virus in a vaccine to be just strong enough | By genetically tweaking the constituent live virus, scientists have created a vaccine against influenza in which the virus is capable of activating the immune system but cannot replicate in healthy cells -- an approach that may become more widely used for generating live virus vaccines adapted to other viruses. | The vaccine proved effective in mice, guinea pigs and ferrets. A major challenge in developing viral vaccines is incorporating enough of the virus to elicit an immune response, while not allowing the virus to run rampant through the body, infecting healthy cells. To overcome this issue, Longlong Si and colleagues modified the genetic code of influenza A virus so that it could only infect and replicate in a cell line they engineered to be dependent on an unnatural amino acid; critically, their modified virus -- though still just as potent in terms of activating the immune system -- cannot replicate in conventional cells.In mice, administering the modified, infected cells in the form of a vaccine offered full protection against influenza.The new vaccine was found to offer an antibody response comparable to an existing live-virus vaccine, and a second dose further increased antibody titers by a factor of six to eight. Similar beneficial effects were seen when the viral vaccine was tested against several different strains of influenza, and tested in guinea pigs and ferrets.These types of virus vaccines can be potentially adapted to almost any virus, the authors say, as long as their genome could be manipulated and packaged in a cell line. | Genetically Modified | 2,016 |
December 1, 2016 | https://www.sciencedaily.com/releases/2016/12/161201122159.htm | Gut microbes promote motor deficits in a mouse model of Parkinson's disease | Gut microbes may play a critical role in the development of Parkinson's-like movement disorders in genetically predisposed mice, researchers report December 1 in | "We have discovered for the first time a biological link between the gut microbiome and Parkinson's disease. More generally, this research reveals that a neurodegenerative disease may have its origins in the gut, and not only in the brain as had been previously thought," says senior study author Sarkis Mazmanian of the California Institute of Technology. "The discovery that changes in the microbiome may be involved in Parkinson's disease is a paradigm shift and opens entirely new possibilities for treating patients."Parkinson's disease affects an estimated one million people and 1% of the United States population over 60 years of age. The disease is caused by the accumulation of abnormally shaped α-synuclein proteins in neurons, leading to particularly toxic effects in dopamine-releasing cells located in brain regions that control movement. As a result, patients experience debilitating symptoms such as tremors, muscle stiffness, slowness of movement, and impaired gait. First-line therapies currently focus on increasing dopamine levels in the brain, but these treatments can cause serious side effects and often lose effectiveness over time.To address the need for safer and more effective treatments, Mazmanian and first author Timothy Sampson of the California Institute of Technology turned to gut microbes as an intriguing possibility. Patients with Parkinson's disease have an altered gut microbiome, and gastrointestinal problems such as constipation often precede motor deficits by many years in these individuals. Moreover, gut microbes have been shown to influence neuronal development, cognitive abilities, anxiety, depression, and autism. However, experimental evidence supporting a role for gut microbes in neurodegenerative diseases has been lacking.The researchers raised genetically modified mice with a Parkinson's-like disease either in normal, non-sterile cages or in a germ-free environment. Remarkably, mice raised in the germ-free cages displayed fewer motor deficits and reducedaccumulation of misfolded protein aggregates in brain regions involved in controlling movement. In fact, these mice showed almost normal performance on tasks such as traversing a beam, removing an adhesive from their nose, and climbing down a pole.Antibiotic treatment had a similar effect as the germ-free environment on ameliorating motor symptoms in mice predisposed to Parkinson's-like disorders. By contrast, mice raised in the germ-free cages showed worse motor symptoms when they either were treated with microbial metabolites called short-chain fatty acids or received fecal transplants of gut microbes from patients with Parkinson's disease. Taken together, the results suggest that gut microbes exacerbate motor symptoms by creating an environment that could favor the accumulation of misfolded protein aggregates.It is important to note that, in this study, gut microbes cooperate with a specific genetic factor to influence the risk for developing Parkinson's disease. The researchers used a specific genetic mouse model that recapitulates motor symptoms through α-synuclein accumulation, and genetically normal mice that were not predisposed to Parkinson's disease did not develop motor symptoms after receiving fecal transplants from patients. Other genetic and environmental factors, such as pesticide exposure, also play a role in the disease.The findings suggest that probiotic or prebiotic therapies have the potential to alleviate the symptoms of Parkinson's disease. However, antibiotics or fecal microbe transplants are far from being viable therapies at this time. "Long-term, high-strength antibiotic use, like we utilized in this study, comes with significant risk to humans, such as defects in immune and metabolic function," Sampson cautions. "Gut bacteria provide immense physiological benefit, and we do not yet have the data to know which particular species are problematic or beneficial in Parkinson's disease."It is therefore critical to identify which pathogenic microbes might contribute to a higher Parkinson's disease risk or to development of a more severe symptomatology -- a research direction the researchers are planning to take. They will also look for specific bacterial species that may protect patients against motor decline. In the end, the identification of microbial species or metabolites that are altered in Parkinson's disease may serve as disease biomarkers or even drug targets, and interventions that correct microbial imbalances may provide safe and effective treatments to slow or halt the progression of often debilitating motor symptoms."Much like any other drug discovery process, translating this innovative work from mice to humans will take many years," Mazmanian says. "But this is an important first step toward our long-term goal of leveraging the deep, mechanistic insights that we have uncovered for a gut-brain connection to help ease the medical, economic, and social burden of Parkinson's disease." | Genetically Modified | 2,016 |
November 28, 2016 | https://www.sciencedaily.com/releases/2016/11/161128113752.htm | Genes, early environment sculpt the gut microbiome | Genetics and birthplace have a big effect on the makeup of the microbial community in the gut, according to research to be published in the journal | The findings by a team of scientists from the Department of Energy's Pacific Northwest National Laboratory (PNNL) and Lawrence Berkeley National Laboratory (Berkeley Lab) represent an attempt to untangle the forces that shape the gut microbiome, which plays an important role in keeping us healthy.In the study, scientists linked specific genes in an animal -- in this case, a mouse -- to the presence and abundance of specific microbes in its gut."We are starting to tease out the importance of different variables, like diet, genetics, and the environment, on microbes in the gut," said PNNL's Janet Jansson, a corresponding author of the study. "It turns out that early life history and genetics both play a role."Scientists studied more than 50,000 genetic variations in mice and ultimately identified more than 100 snippets that affect the population of microbes in the gut. Some of those genes in mice are very similar to human genes that are involved in the development of diseases like arthritis, colon cancer, Crohn's disease, celiac disease, and diabetes.The abundance of one microbe in particular, a probiotic strain of "We know the microbiome likely plays an important role in fighting infections," said first author Antoine Snijders of Berkeley Lab. "We found that the level of T-helper cells in the blood of mice is well explained by the level of To do the research, the team drew upon a genetically diverse set of "collaborative cross" mice that capture the genetic variation in human populations. Scientists studied 30 strains of the mice, which were housed in two facilities with different environments for the first four weeks of their lives. The scientists took fecal samples from the mice to characterize their gut microbiomes before transferring them to a third facility.The researchers found that the microbiome retained a clear microbial signature formed where the mice were first raised -- effectively their "hometown." Moreover, that microbial trait carried over to the next generation, surprising the scientists."The early life environment is very important for the formation of an individual's microbiome," said Jian-Hua Mao, a corresponding author from Berkeley Lab. "The first dose of microbes one gets comes from the mom, and that remains a strong influence for a lifetime and even beyond."In brief, the team found that:• Both genetics and early environment play a strong role in determining an organism's microbiome• The genes in mice that were correlated to microbes in the gut are very similar to genes that are involved in many diseases in peopleThe researchers also found indications that moderate shifts in diet play a role in determining exactly what functions the microbes carry out in the gut."Our findings could have some exciting implications for people's health," said Jansson. "In the future, perhaps people could have designer diets, optimized according to their genes and their microbiome, to digest foods more effectively or to modulate their susceptibility to disease." | Genetically Modified | 2,016 |
November 22, 2016 | https://www.sciencedaily.com/releases/2016/11/161122182355.htm | New grasses neutralize toxic pollution from bombs, explosives, and munitions | On military live fire training ranges, troops practice firing artillery shells, drop bombs on old tanks or derelict buildings and test the capacity of new weapons. | But those explosives and munitions leave behind toxic compounds that have contaminated millions of acres of U.S. military bases -- with an estimated cleanup bill ranging between $16 billion and $165 billion.In a paper published online Nov. 16 in UW engineers introduced two genes from bacteria that learned to eat RDX and break it down into harmless components in two perennial grass species: switchgrass (Panicum virgatum) and creeping bentgrass (Agrostis stolonifera). The best-performing strains removed all the RDX from a simulated soil in which they were grown within less than two weeks, and they retained none of the toxic chemical in their leaves or stems.It is the first reported demonstration of genetically transforming grasses to supercharge their ability to remove contamination from the environment. Grasses are hearty, fast-growing, low-maintenance plants that offer practical advantages over other species in real-world cleanup situations."This is a sustainable and affordable way to remove and destroy pollutants on these training ranges," said senior author and UW professor of civil and environmental engineering Stuart Strand, whose lab focuses on taking genes from microorganisms and animals that are able to degrade toxic compounds and engineering them into useful plants."The grasses could be planted on the training ranges, grow on their own and require little to no maintenance. When a toxic particle from the munitions lands in a target area, their roots would take up the RDX and degrade it before it can reach groundwater," Strand said.RDX is an organic compound that forms the base for many common military explosives, which can linger in the environment in unexploded or partially exploded munitions. In large enough doses, it has been shown to cause seizures and organ damage, and it's currently listed by the Agency for Toxic Substances & Disease Registry as a potential human carcinogen.Unlike other toxic explosives constituents such as TNT -- which binds to soils and tends to stay put -- RDX dissolves easily in water and is more prone to spread contamination beyond the limits of a military range, manufacturing facility or battleground."Particles get scattered around and then it rains," Strand said. "Then RDX dissolves in the rainwater as it moves down through the soil and winds up in groundwater. And, in some cases, it flows off base and winds up in drinking water wells."Wild grass species do remove RDX contamination from the soil when they suck water up through their roots, but they don't significantly degrade it. So when the grasses die, the toxic chemical is re-introduced into the landscape.Co-authors Neil Bruce and Liz Rylott, biotechnology professor and research scientist, respectively, at the University of York and colleagues had previously isolated enzymes found in bacteria that evolved to use the nitrogen found in RDX as a food source. That digestion process has the added benefit of degrading the toxic RDX compound into harmless constituents.The bacteria themselves aren't an ideal cleanup tool because they require other food sources that aren't always present on military training ranges. So Bruce and Rylott tried inserting the bacterial genes into plant species commonly used in laboratory settings. Those experiments proved that the new plant strains were able to remove RDX contamination much more successfully than their wild counterparts."Considering the worldwide scale of explosives contamination, plants are the only low cost, sustainable solution to cleaning up these polluted sites," said Bruce.The UW team of civil and environmental engineers spent eight years working to express the same genes in plant species that could stand up to real-world use. They needed a hearty perennial species that grows back year after year and that has strong root systems that can bounce back after fires.Grasses fit that bill, but they are more difficult to manipulate genetically. In particular, the UW engineers had to build into their gene constructs robust monocot "promoters" -- or regions of DNA that cause a particular gene to be expressed -- for the process to work in grass species."For cleaning up contaminated soils, grasses work best, but they're definitely not as easy to transform, especially since flexible systems to express multiple genes in grasses have not been used before," said first author and acting UW instructor Long Zhang.The research team also found another unexpected side benefit: because the genetically modified grasses use RDX as a nitrogen source, they actually grow faster than wild grass species.Next steps for the UW research team include limited field trials on a military training range to test how the strains perform under different conditions. Wider use would require USDA approval to ensure that the genetic modifications pose no threat to wild grass species."I think it would be ecologically acceptable because the genes we've introduced degrade real pollutants in the environment and cause no harm," Strand said. "From my perspective, this is a useful technology that's beneficial to the environment and has the potential to remove dangerous legacy contamination from decades of military activity." | Genetically Modified | 2,016 |
November 17, 2016 | https://www.sciencedaily.com/releases/2016/11/161117152501.htm | DNA evidence from 5,310-year-old corn cob fills gaps in history | Researchers who have sequenced the genome of a 5,310-year-old corn cob have discovered that the maize grown in central Mexico all those years ago was genetically more similar to modern maize than to its wild ancestor. For example, the ancient maize already carried genetic variants responsible for making kernels soft, a common feature of modern corn. The findings are reported in | "Around 9,000 years ago in modern-day Mexico, people started collecting and consuming teosinte, a wild grass," says Nathan Wales of the Natural History Museum of Denmark. "Over the course of several thousand years, human-driven selection caused major physical changes, turning the unproductive plant into modern maize, commonly known as corn. Maize as we know it looks so different from its wild ancestor that a couple of decades ago scientists had not reached a consensus regarding the true ancestor of maize."To better understand the domestication history of the world's most produced crop, Wales and his colleagues, including Jazmín Ramos-Madrigal, sequenced the genome of a 5,310-year-old maize cob from central Mexico. The cob, known as Tehuacan162, was excavated from a cave in the Tehuacan Valley in the 1960s, during a major archaeological expedition lead by Richard MacNeish.Fortunately, the Robert S. Peabody Museum in Andover, MA, took excellent care of the ancient maize specimen -- one of the five oldest known in the world -- for decades. Wales explains that this particular cob and the DNA within it had been unusually well preserved."Archaeological specimens frequently have high levels of bacterial DNA due to decomposition and soil contaminants," he says. "However, during genetic testing of ancient cobs, we were astonished to find that 70 percent of the DNA from the Tehuacan162 cob was from the plant!" Most other ancient samples contain less than 10 percent plant DNA.Tehuacan162 didn't have hard seed coats like its wild ancestor would have. But, the ancient cob is less than a tenth of the size of modern cobs, at less than two centimeters long. In addition, the ancient cob produced only eight rows of kernels, about half that of modern maize. That led the researchers to suspect that its genes would offer clues on the early stages of maize domestication.To make the most of the small sample, Wales and Ramos-Madrigal used cutting-edge paleogenomic techniques. They extracted DNA with a method designed to recover ultra-short DNA, taking special care to avoid losing any genetic material. As a result, the researchers were able to prepare sufficient DNA for sequencing while still preserving enough of the sample to determine the cob's precise age via radiocarbon dating.The new findings offer an informative snapshot in the 10,000-year evolutionary history of maize and its domestication, the researchers say. In addition to elucidating how maize provided a dietary foundation for ancient civilizations like the Maya, such studies can also aid in understanding and improving commercially important lines of modern maize, the researchers say."This is only the beginning of the story," Ramos-Madrigal says. "Humans dispersed maize across the Americas very quickly and very successfully. We want to know how humans dispersed it, which routes they took, and how maize adapted to such diverse environments." | Genetically Modified | 2,016 |
November 17, 2016 | https://www.sciencedaily.com/releases/2016/11/161117134629.htm | Tasting light: New type of photoreceptor is 50 times more efficient than the human eye | An international team of scientists led by the University of Michigan has discovered a new type of photoreceptor -- only the third to be found in animals -- that is about 50 times more efficient at capturing light than the rhodopsin in the human eye. | The new receptor protein, LITE-1, was found among a family of taste receptors in invertebrates, and has unusual characteristics that suggest potential future applications ranging from sunscreen to scientific research tools, the team noted in findings scheduled to be published Nov. 17 in the journal "Our experiments also raise the intriguing possibility that it might be possible to genetically engineer other new types of photoreceptors," said senior study author Shawn Xu, a faculty member of the U-M Life Sciences Institute, where his lab is located.The LITE-1 receptor was discovered in the eyeless, millimeter-long roundworms known as nematodes, a common model organism in bioscience research."LITE-1 actually comes from a family of taste receptor proteins first discovered in insects," said Xu, who is also a professor in the Department of Molecular and Integrative Physiology at the U-M Medical School. "These, however, are not the same taste receptors as in mammals."Xu's lab previously demonstrated that although they lack eyes, the worms will move away from flashes of light. The new research goes a step further, showing that LITE-1 directly absorbs light, rather than being an intermediary that senses chemicals produced by reactions involving light."Photoreceptors convert light into a signal that the body can use," Xu said. "LITE-1 is unusual in that it is extremely efficient at absorbing both UV-A and UV-B light -- 10 to 100 times greater than the two other types found in the animal kingdom: opsins and cryptochromes. The next step is to better understand why it has these amazing properties."The genetic code of these receptor proteins is also very different from other types of photoreceptors found in plants, animals and microbes, Xu said.Characterizing the current research as an "entry point," the researchers said the discovery might prove useful in a variety of ways.With further study, for example, it might be possible to develop LITE-1 into a sunscreen additive that absorbs harmful rays, or to further scientific research by fostering light sensitivity in new types of cells, the scientists wrote in the paper.Several characteristics make LITE-1 unusual, Xu said.Animal photoreceptors typically have two components: a base protein and a light-absorbing chromophore (a role played by retinal, or vitamin A, in human sight). When you break these photoreceptors apart, the chromophore still retains some of its functionality.This is not the case for LITE-1. Breaking it apart, or "denaturing" it, completely stops its ability to absorb light, rather than just diminishing it -- showing that it really is a different model, Xu said.The researchers also determined that within the protein, having the amino acid tryptophan in two places was critical to its function.When a nonlight-sensitive protein in the same family, GUR-3, was modified to add the corresponding tryptophan residues, it reacted strongly to ultraviolet light -- with about a third the sensitivity to UV-B as LITE-1."This suggests scientists may be able to use similar techniques to genetically engineer other new photoreceptors," Xu said. | Genetically Modified | 2,016 |
November 14, 2016 | https://www.sciencedaily.com/releases/2016/11/161114142353.htm | Biologists give bacteria thermostat controls | A new helper in the fight against cancer and other diseases of the gut may be genetically altered bacteria that release medicines to tumors or the gut. | Now, a new study performed using mice demonstrates how doctors might one day better regulate those therapeutic microbes by engineering them to respond to temperature. For instance, if engineered bacteria were administered to a patient with a disease, doctors could, in theory, instruct the bacteria to release medicine to just the site of interest, and nowhere else in the body, by using ultrasound to gently heat up the tissue."Bacteria can be designed to act like special agents fighting disease in our bodies," says Caltech's Mikhail Shapiro, assistant professor of chemical engineering and Heritage Principal Investigator, whose overall research goal is to create new ways to both visualize and control cells -- bacterial cells and human cells -- for medicinal purposes. "We're building walkie-talkies for the cells so we can both listen and talk to them."Shapiro is principal investigator on a paper about the new research published November 14 in the journal The research also shows how these engineered bacteria, once in a patient, could be programmed to stop administering a therapeutic or to self-destruct if the patient's temperature rises from a fever. A fever might signal that the therapy is not working, and thus it would be in the patient's best interest for the bacteria to terminate its activity.In another application of the technology, the researchers demonstrated how the bacteria could be designed to destroy themselves once they leave a patient's body through defecation. The lower temperature outside of a host's body would signal the engineered bacteria to activate a genetic kill switch, thereby alleviating concerns about the genetically altered microbes spreading to the environment."We can use these thermal switches in bacteria to control a variety of behaviors," says Shapiro.The strategy of using engineered bacteria to fight disease -- part of a growing field called microbial therapeutics -- has shown some promise in animal models and humans. Previous research has demonstrated that some bacteria naturally make their way to tumor sites because they prefer the tumors' low-oxygen environments. Studies have shown that these bacteria can be directed to release a medicine onto tumors, such as the tumor-destroying drug hemolysin. Other studies have shown that bacteria administered to the gut can release molecules to reduce inflammation. But these bacteria might end up in other portions of the body, and not just at the sites of interest.The method developed by Shapiro's lab solves this problem by providing a mechanism through which bacteria can be instructed to direct drugs only to a specific anatomical site. The idea is that the genetically engineered bacteria would activate their therapeutic program at a certain temperature induced via ultrasound tools, which gently heat tissues with millimeter precision. A doctor could, in theory, administer genetically altered bacteria to a cancer patient and then, by focusing ultrasound at the tumor site, trigger the bacteria to fight the tumor."We can spatially and temporally control the activity of the bacteria," says Abedi. "We can communicate with them and tell them when and where something needs to be done."To create thermally controllable bacteria, the team first needed to find candidate genetic switches whose activity depends on temperature changes. They ultimately identified two candidates. The first is a protein in Next, the scientists used a protein engineering technique -- "directed evolution," pioneered by Caltech's Frances Arnold -- to evolve the proteins in the lab and tune their switching temperatures. For instance, the "When we were thinking about how to get bacteria to sense temperature, we looked at nature and found a few systems where bacteria can do this," says Piraner. "We tested the performance, found the ones that had the best switching performance. From there, we went on to find that they could be tuned and amplified. It all started with what nature gave us, and engineering took us the rest of the way." | Genetically Modified | 2,016 |
November 9, 2016 | https://www.sciencedaily.com/releases/2016/11/161109181906.htm | People who know about genetically modified food agree with science: They're safe | People who know a lot about genetically modified foods are inclined to agree with the scientific consensus that such foods are safe to eat. But, those who know plenty about global warming are cautious about the science that says humans cause the phenomenon, a new University of Florida Institute of Food and Agricultural Sciences study shows. | Furthermore, the study showed some people still make what researchers call "illusionary correlations," such as "genetically modified foods cause autism."Perhaps science communication should address people's perceptions about illusionary correlations versus their knowledge of global warming and genetically modified foods, said Brandon McFadden, a UF/IFAS assistant professor of food and resource economics and author of the study. Merely providing people with information is insufficient to change behavior, McFadden said.Genetically modified (GM) foods are defined by the World Health Organization as foods derived from organisms whose genetic material has been modified in a way that does not occur naturally, for example, through the introduction of a gene from a different organism. Most genetically modified crops have been modified to be resistant to plant diseases or to increase tolerance of herbicides, according to the WHO website (McFadden cited in his paper a recent Pew Research Center survey of scientists and the U.S. general public. Most of the scientists (88 percent) agreed that GM foods are safe to eat, compared to 37 percent of U.S. adults. The survey also found that most scientists (87 percent) agree that human activities cause global warming, compared to 50 percent of American adults.McFadden wanted to know more about the reasons for the gap between public opinion and scientific consensus.In a study published Nov. 9 in the online journal McFadden asked any array of questions. Among those questions trying to find out participants' knowledge about genetically modified food, he asked "true/false" questions such as: "Ordinary tomatoes do not contain genes while genetically modified tomatoes do." Only 31.9 percent said that was true.He also asked questions to measure illusory correlations such as, "To what extent do you agree with the following statement: 'Genetically modified crops have caused an increase in food allergies.'" To that, 36 percent either agreed or strongly agreed.And there were several questions about global warming, including: "True or false: The greenhouse effect is the same thing as global warming." Some 45 percent said this was true."Intuitively, it would seem that greater knowledge would be associated with being more agreeable with science," McFadden said. "Indeed, individuals with greater knowledge are more agreeable with science in general; however, people with greater knowledge become less agreeable when the issues are contentious." | Genetically Modified | 2,016 |
November 9, 2016 | https://www.sciencedaily.com/releases/2016/11/161109100722.htm | Targeting pathogenic bacteria | Bacterial pathogens pose serious health risks, especially for infants, young children, elderly and those with compromised immune systems. The evolution of drug-resistant bacteria is particularly concerning in the fight against disease. A research team in Canada is exploring a new platform for detecting pathogenic bacteria using bacteriophages, viruses that use bacteria as their host. | During the AVS 63rd International Symposium and Exhibition being held November 6-11, 2016, in Nashville, Tennessee, Stephane Evoy, an applied physicist from the University of Alberta, will explain how the team recognized the limited reliability of antibodies in providing bacteria detection with specificity. Instead they used phage-derived proteins, proteins developed from the bacteria-invading viruses, for detection of pathogenic bacteria to address this deficiency. This work has implications not only in disease diagnosis, but also in food and water safety."The high specificity of phages offers a potent alternative for the targeting of pathogens," Evoy said. "More specifically, recombinant phage-receptor-binding proteins (RBPs) responsible for phage-host specificity can be used as biological probes and present numerous advantages over the use of a whole phage."The study used skim cow milk spiked with different phages or combinations of phages, such as mycobacteria (MAP) and Escherichia coli cells, and a unique process to capture the DNA after incubation. The entire process took less than 24 hours and resulted in significantly better sensitivity of detecting targeted DNA."The use of phage-derived proteins in such a manner was quite unique when we started that work back in 2005, but since then the approach thrived, and multinational companies integrated this into their product line," Envoy said. "However, there is still a lot of work to be done in terms of applying the technology to diseases such as tuberculosis and staphylococcus infections."In addition to demonstrating this capture technique, the research team designed and developed a sophisticated bacteria detector comprised of an array of microresonators, able to enumerate bacteria over a large area and detect the attachment of a single cell anywhere on the array. The devices were prepared with their phage proteins, adding this high specificity of detection to the spatial precision offered by the array design."We are looking forward to adapting this technology for the rapid diagnosis of drug-resistant bacteria," Evoy said. "It could go a long way toward make microbial testing methods both more rapid and affordable." | Genetically Modified | 2,016 |
November 8, 2016 | https://www.sciencedaily.com/releases/2016/11/161108115714.htm | Model predicts elimination of GMO crops would cause hike in greenhouse gas emissions | A global ban on genetically modified crops would raise food prices and add the equivalent of nearly a billion tons of carbon dioxide to the atmosphere, a study by researchers from Purdue University shows. | Using a model to assess the economic and environmental value of GMO crops, agricultural economists found that replacing GMO corn, soybeans and cotton with conventionally bred varieties worldwide would cause a 0.27 to 2.2 percent increase in food costs, depending on the region, with poorer countries hit hardest. According to the study, published Oct. 27 in the Conversely, if countries that already plant GMOs expanded their use of genetically modified crops to match the rate of GMO planting in the United States, global greenhouse gas emissions would fall by the equivalent of 0.2 billion tons of carbon dioxide and would allow 0.8 million hectares of cropland (about 2 million acres) to return to forests and pastures."Some of the same groups that want to reduce greenhouse gas emissions also want to ban GMOs. But you can't have it both ways," said Wally Tyner, the James and Lois Ackerman Professor of Agricultural Economics. "Planting GMO crops is an effective way for agriculture to lower its carbon footprint."GMOs have been a source of contention in the United States and abroad, as some believe genetically modified crops pose potential risks to human health and the environment. Three U.S. regulatory agencies -- the Department of Agriculture, the Food and Drug Administration and the Environmental Protection Agency -- have deemed GMO foods safe to eat, and the United States is the global leader in planting GMO crops and developing agricultural biotechnology.But in many European and Asian countries, consumer and economic concerns have led to strict regulations on GMO crops, with partial or full bans on their cultivation.Tyner and fellow researchers Farzad Taheripour, research associate professor of agricultural economics, and then-master's student Harry Mahaffey used an extension of the Purdue-developed Global Trade Analysis Project (GTAP-BIO) model to investigate two hypothetical scenarios: "What economic and environmental effects would a global ban on GMO corn, soybeans and cotton have?" and "What would be the additional impact if global GMO adoption caught up to the U.S. and then a ban were implemented?"The model is set to 2011 crop prices, yields and growing conditions and encompasses the ripple effects of how a change in one sector impacts other sectors.GTAP-BIO predicted a modest and region-specific rise in overall food costs under a global GMO ban, a result of the lower productivity of non-GMO crops. Tyner said people in poorer regions would be most burdened by the price increase, as they spend about 70 percent of their income on food, compared with about 10 percent in the U.S.Countries that export crops would gain economically by the increase in food prices, while countries that import crops would suffer. As a result, the U.S., despite being the biggest planter of GMO crops, would profit under a GMO ban because of its strength as a crop producer and exporter. China, a major crop importer, would suffer a welfare loss -- a measure of economic wellbeing -- of $3.63 billion."The U.S. is the largest agricultural exporter, so if the price of agricultural products goes up, we benefit," Tyner said.Banning GMO crops would also lead to an increase in global cropland of 3.1 million hectares (about 7.7 million acres), as land would be cleared to compensate for the lower yields of conventional crops. Converting forests and pastures into farmland is an environmentally-costly process that releases carbon stored in plants and soil, and this expansion of cropland would add the equivalent of 0.92 billion tons of carbon dioxide to the atmosphere.Tyner said the economic consequences of a GMO ban came as no surprise to him and his co-authors, but the toll such a ban would have on the environment was an eye-opener -- and a component that is notably missing from global discussion of GMOs."It's quite fine for people to be concerned about GMOs -- there's no scientific basis to those concerns, but that's their right," he said. "But the adverse impact on greenhouse gases without GMOs is something that is not widely known. It is important that this element enter into the public conversation." | Genetically Modified | 2,016 |
October 26, 2016 | https://www.sciencedaily.com/releases/2016/10/161026105132.htm | Mulberry extract activates brown fat, shows promise as obesity treatment | Good news for those who want to activate their brown fat (or BAT, brown adipose tissue) without having to be cold: New research, published in | "The beneficial effects of rutin on BAT-mediated metabolic improvement have evoked a substantial interest in the potential treatment for obesity and its related diseases, such as diabetes," said Wan-Zhu Jin, Ph.D., a researcher involved in the work from the Institute of Zoology at the Chinese Academy of Sciences in Beijing, China. "In line with this idea, discovery of more safe and effective BAT activators is desired to deal with obesity and its related diseases."To make their discovery, Jin and colleagues used both genetically obese mice and mice with diet-induced obesity as models. These mice were fed a regular diet, and supplemental rutin (1 mg/ml) was added to their drinking water. Rutin treatment significantly reduced adiposity, increased energy expenditure, and improved glucose homeostasis in both the genetically obese mice and the mice with diet-induced obesity. Specifically, the researchers found that rutin directly binds to and stabilizes SIRT1 (NAD-dependent deacetylase sirtuin-1), leading to hypoacetylation of PGC1α protein, which stimulates Tfam transactivation and eventually augments mitochondrial number and UCP1 activity in BAT. Rutin functions as a cold mimetic through activating a SIRT1-PGC1α-Tfam signaling cascade and increasing mitochondrial number and UCP1 activity in BAT. Rutin also induced brown-like (beige) adipocyte formation in subcutaneous adipose tissue in both obesity mouse models."Unlike hibernating animals, we humans have only a small spot of brown fat, and yet its importance in human metabolism has only recently come into view," said Thoru Pederson, Ph.D., Editor-in-Chief of | Genetically Modified | 2,016 |
October 20, 2016 | https://www.sciencedaily.com/releases/2016/10/161020142815.htm | Tobacco plants engineered to manufacture high yields of malaria drug | In 2015, the Nobel Prize in Physiology or Medicine was awarded in part for the discovery of artemisinin, a plant-derived compound that's proven to be a lifesaver in treating malaria. Yet many people who need the drug are not able to access it, in part because it's difficult to grow the plant that is the compound's source. Now, research has shown that tobacco plants can be engineered to manufacture the drug at therapeutic levels. The study appears October 20 in | "Artemisinin treats malaria faster than any other drug. It can clear the pathogen from the bloodstream within 48 hours," says senior author Shashi Kumar, of the International Centre for Genetic Engineering and Biotechnology in New Delhi, India. "Our research is focused on finding a way to make this drug available to more people."Malaria infects more than 200 million people every year, according to the World Health Organization, and kills more than 400,000, mostly in Africa and Southeast Asia. The majority of those who live in malaria-stricken areas cannot afford to buy artemisinin. The drug's high cost is due to the extraction process and largely to the fact that it's difficult to grow Artemisia annua (sweet wormword), the plant that is the original source of the drug, in climates where malaria is common, such as in India. Advances in synthetic biology have made it possible to produce the drug in yeast, but the manufacturing process is difficult to scale up.Earlier studies looked at growing the compound in tobacco -- a plant that's relatively easy to genetically manipulate and that grows well in areas where malaria is endemic. But yields of artemisinin from those plants were low.In the current paper, Kumar's team reports using a dual-transformation approach to boost the production of artemisinin in the tobacco plants: they first generated plants that contained transgenic chloroplasts, and the same plants were then manipulated again to insert genes into the nuclear genome as well. "We rationalized the expression of biosynthetic pathway's gene in different compartment that enabled us to reach the maximum yield from the double transgenic plants," he says.Extract from the plants was shown to stop the growth progression of pathogen-infected red blood cells in vitro. Whole cells from the plant were also fed to mice infected with Plasmodium berghei, one of the microbes that causes malaria. The plant product greatly reduced the level of the parasite in the blood. In fact, the researchers found, the whole plant material was more effective in attacking the parasite than pure artemisinin, likely because encapsulation inside the plant cells protected the compound from degradation by digestive enzymes.But Kumar and his colleagues acknowledge that convincing people to eat tobacco plants is likely to be a hard sell. For that reason, he is collaborating with Henry Daniell, a professor of biochemistry at the University of Pennsylvania and one of the study's coauthors, with a plan to genetically engineer lettuce plants for producing artemisinin. The lettuce containing the drug can then be freeze dried, ground into a powder, and put into capsules for cost-effective delivery."Plant and animal science are increasingly coming together," Kumar says. "In the near future, you will see more drugs produced inside plants will be commercialized to reduce the drug cost." | Genetically Modified | 2,016 |
October 18, 2016 | https://www.sciencedaily.com/releases/2016/10/161018133142.htm | Mystery species hidden in cave art appears to be unknown bison-cattle hybrid | Ancient DNA research has revealed that Ice Age cave artists recorded a previously unknown hybrid species of bison and cattle in great detail on cave walls more than 15,000 years ago. | The mystery species, known affectionately by the researchers as the Higgs Bison* because of its elusive nature, originated over 120,000 years ago through the hybridisation of the extinct Aurochs (the ancestor of modern cattle) and the Ice Age Steppe Bison, which ranged across the cold grasslands from Europe to Mexico.Research led by the Australian Centre for Ancient DNA (ACAD) at the University of Adelaide, published today in "Finding that a hybridisation event led to a completely new species was a real surprise -- as this isn't really meant to happen in mammals," says study leader Professor Alan Cooper, ACAD Director. "The genetic signals from the ancient bison bones were very odd, but we weren't quite sure a species really existed -- so we referred to it as the Higgs Bison."The international team of researchers also included the University of California, Santa Cruz (UCSC), Polish bison conservation researchers, and palaeontologists across Europe and Russia. They studied ancient DNA extracted from radiocarbon-dated bones and teeth found in caves across Europe, the Urals, and the Caucasus to trace the genetic history of the populations.They found a distinctive genetic signal from many fossil bison bones, which was quite different from the European bison or any other known species.Radiocarbon dating showed that the mystery species dominated the European record for thousands of years at several points, but alternated over time with the Steppe bison, which had previously been considered the only bison species present in Late Ice Age Europe."The dated bones revealed that our new species and the Steppe Bison swapped dominance in Europe several times, in concert with major environmental changes caused by climate change," says lead author Dr Julien Soubrier, from the University of Adelaide. "When we asked, French cave researchers told us that there were indeed two distinct forms of bison art in Ice Age caves, and it turns out their ages match those of the different species. We'd never have guessed the cave artists had helpfully painted pictures of both species for us."The cave paintings depict bison with either long horns and large forequarters (more like the American bison, which is descended from the Steppe bison) or with shorter horns and small humps, more similar to modern European bison."Once formed, the new hybrid species seems to have successfully carved out a niche on the landscape, and kept to itself genetically," says Professor Cooper. "It dominated during colder tundra-like periods, without warm summers, and was the largest European species to survive the megafaunal extinctions. However, the modern European bison looks genetically quite different as it went through a genetic bottleneck of only 12 individuals in the 1920s, when it almost became extinct. That's why the ancient form looked so much like a new species."Professor Beth Shapiro, UCSC, first detected the mystery bison as part of her PhD research with Professor Cooper at the University of Oxford in 2001. "Fifteen years later it's great to finally get to the full story out. It's certainly been a long road, with a surprising number of twists," Professor Shapiro says.*The Higgs Boson is a subatomic particle suspected to exist since the 1960s and only confirmed in 2012. | Genetically Modified | 2,016 |
October 16, 2016 | https://www.sciencedaily.com/releases/2016/10/161016141132.htm | California condors' genetic bottleneck: New evidence | The existing genetic diversity of California Condors, all of which are descended from just 14 individuals, is strikingly low. But were condors more genetically diverse before their 20th century population crash, or were they already, as one paleontologist put it in the 1940s, a Pleistocene relict with "one wing in the grave"? The researchers behind a new study in | Analyzing the museum specimens' mitochondrial DNA, Jesse D'Elia of the U.S. Fish and Wildlife Service and his colleagues showed that more than 80% of the unique haplotypes present in the birds of the past have disappeared from the gene pool of condors alive today. The low amount of genetic diversity in the current population, which is descended from only 14 genetic founders from the captive flock, was already well known, but this was the first study to show that there was substantial genetic diversity in the historical population.D'Elia and his colleagues used tissue samples from 93 California Condor specimens collected between 1825 and 1984 in locations ranging from Mexico to Washington state. "The value of museum collections for answering important questions when considering population translocations and species' reintroductions cannot be overstated," says D'Elia. "They provide a direct window into a population's history and as new genetic and genomic tools continue to be developed the value of these specimens only increases."The genetic bottleneck resulted in inbreeding and decreased fitness, and condors will continue to require intensive management for some time to recover. But there is a possible upside for condor conservation in the results of this study -- D'Elia and his colleagues did not find any evidence that the now-vanished Pacific Northwest population was genetically isolated from the condors in California. If Northwest condors weren't on a separate evolutionary track, there's no reason not to release today's captive-bred condors into those unoccupied areas of their historical range."These results document a significant decline in mitochondrial DNA diversity over the past century, which also suggests a corresponding reduction in nuclear DNA diversity," according to Jeff Johnson of the University of North Texas, an expert on incorporating genetic information into conservation efforts. "Therefore, the careful attention made to maintain founder lineages and prevent inbreeding is critical for improving the likelihood of producing an eventual self-sustainable wild population. Those involved in the California Condor recovery efforts are leading experts in captive propagation and release, and the methods developed and used, particularly those benefiting from whole nuclear genome approaches, acknowledge the importance of maintaining existing genomic diversity both at the individual and population level. These methods will also benefit other endangered species captive breeding programs that possess similar demographic histories." | Genetically Modified | 2,016 |
October 14, 2016 | https://www.sciencedaily.com/releases/2016/10/161014102652.htm | Human transport has unpredictable genetic, evolutionary consequences for marine species | New research, led by the University of Southampton, has found that human activities such as shipping are having a noticeable impact on marine species and their native habitats. | The research, published in the journal Lead author and PhD Student Jamie Hudson said: "Marine species are expected to develop populations whereby geographically close populations are more genetically similar than geographically distant populations. However, anthropogenic (environmental change caused by humans) activities such as shipping promote the artificial transport of species and bring distant populations together, leading to the crossing of individuals and therefore genetic material. The disruption of pre-modern genetic patterns through anthropogenic activities is an unprecedented form of global change that has unpredictable consequences for species and their native distributions."The researchers investigated the genetics of a native marine invertebrate species (the tunicate Ciona intestinalis) in the English Channel, an area with a high prevalence of shipping. Ciona intestinalis has restricted dispersal capabilities and is most often reported in artificial habitats, such as marinas, so are therefore readily transported by human activities.They collected specimens between June and December 2014 from 15 different locations on the English and French coasts. They looked at sections of DNA called microsatellites (areas of DNA that contain repeating sequences of two to five base pairs), which can be read and can help determine how similar populations are to each other.They found a mosaic of genetic patterns that could not be explained by the influence of natural or anthropogenic means alone.Jamie, who is based in the Ecology and Evolution Lab, added: "We found that C. intestinalis from some locations exhibited a shuffling of genetic material, as expected by human-mediated transport (boats can travel further distances than the larvae). However, unexpectedly some of the populations exhibited the opposite pattern (some populations were not genetically similar), despite there being evidence of artificial transport between these locations -- this may be due to natural dispersal or premodern population structure.Taken together, the authors found dissimilar patterns of population structure in a highly urbanised region that could not be predicted by artificial transport alone. They conclude that anthropogenic activities alter genetic composition of native ranges, with unknown consequences for species' evolutionary trajectories.The research was conducted by Jamie, under the supervision of Dr Marc Rius from the University of Southampton, and Dr. Frédérique Viard and Charlotte Roby at the Station Biologique de Roscoff, in France. This study was funded by the ANR project HYSEA and the University of Southampton. | Genetically Modified | 2,016 |
October 13, 2016 | https://www.sciencedaily.com/releases/2016/10/161013155130.htm | Antifungal RNA spray could help fight barley crop disease | Spraying barley crops with RNA molecules that inhibit fungus growth could help protect the plants against disease, according to a new study published in | Plant diseases caused by fungi that grow on crops seriously threaten the world's food supply, and fungi can develop resistance to traditional pesticides. To improve the antifungal arsenal, Aline Koch of Justus Liebig University, Germany, and colleagues are investigating RNA-based techniques that fight fungi at the genetic level.In the new study, Koch's team sprayed a double-stranded RNA molecule called CYP3-dsRNA onto barley leaves and exposed the plants to a common disease-causing fungus known as F. graminearum. When absorbed by fungal cells, CYP3-dsRNA is known to target and silence the expression of three key F. graminearum genes, inhibiting the pathogen's growth.The scientists found that CYP3-dsRNA inhibited fungus growth on sprayed plants but not on unsprayed plants. The researchers also found reduced F. graminearum growth on leaves that were not directly sprayed with CYP3-dsRNA, suggesting that the plant's vascular system can transport the RNA from sprayed leaves to distant infection sites. Further experiments demonstrated that a fungal protein known as DICER-LIKE 1 is important for CYP3-dsRNA to inhibit growth effectively.These findings will help inform future research into RNA-based control of plant pathogens. Koch's team had previously shown that barley plants can be genetically modified to produce CYP3-dsRNA themselves. However, scientific and societal obstacles to genetic engineering pose challenges for this technique. Spraying RNA directly onto crops could be a more viable, sustainable, and environmentally friendly alternative."The discovery that spraying of small RNAs targeting essential genes of the fungus Fungus graminearum," the authors report, "reduced its plant infection adverts to a new generation of environmentally-friendly fungicides." | Genetically Modified | 2,016 |
October 11, 2016 | https://www.sciencedaily.com/releases/2016/10/161011131301.htm | Virus carrying DNA of black widow spider toxin | A tiny virus that may sting like a black widow spider. | That is one of the surprise discoveries made by a pair of Vanderbilt biologists when they sequenced the genome of a virus that attacks Wolbachia, a bacterial parasite that has successfully infected not only black widow spiders but more than half of all arthropod species, which include insects, spiders and crustaceans."Discovering DNA related to the black widow spider toxin gene came as a total surprise because it is the first time that a phage -- a virus that infects bacteria -- has been found carrying animal-like DNA," said Associate Professor of Biological Sciences Seth Bordenstein. He and Senior Research Specialist Sarah Bordenstein reported the results of their study in a paper titled "Eukaryotic association module in phage WO genomes from Wolbachia" published Oct. 11 in the journal Nature Communications.Normally phages, like the WO phage that they studied, carry specialized genes that break open and defeat the defenses of the prokaryotic bacterial cells they target. But in this case, "the portion of DNA related to the black widow spider toxin gene is intact and widespread in the phage," said Bordenstein. "There is also evidence that the phage makes insecticidal toxins, but we are not certain yet how these are utilized and administered."The scientists also found that WO shares a number of other segments of DNA with animal genomes. These include a sequence that the eukaryotic cells found in animals use to sense pathogens, which is also involved in triggering cell death. In addition, there were several genes that the cells use to evade immune responses. "These sequences are more typical of eukaryotic viruses, not phages," Bordenstein commented.He speculated that the reason WO is exceptional in this regard is due to the life history of its target. Once Wolbachia infect a host arthropod, it wraps itself in a layer of the arthropod's membrane. As a result, the phage has to force its way through these eukaryotic membranes in order to enter or escape."We suspect it makes pores in the membranes of the arthropod cells that surround Wolbachia, thereby allowing the phage to overcome both the bacterial and arthropod membranes that surround it. That may be how it uses some of these proteins" he said.Their sequencing and bioinformatic efforts also allowed the Bordensteins to identify the genetic sequences that phage WO uses to insert its genome into theWolbachia chromosome. This information may provide a basic toolkit that can be used to genetically engineer the bacterium.This capability could be used to enhance ongoing efforts that use Wolbachia to fight dengue fever and Zika virus. It turns out that Wolbachia prevents these viruses from reproducing in Aedes aegypti mosquitoes that spread them. Infecting and spreading mosquitoes with Wolbachia has been successfully field tested in Australia, Brazil, Columbia, Indonesia and Vietnam.Use of the bacterial parasite has two potential advantages compared to other approaches: It doesn't rely on toxic chemicals and, once it is introduced, the bacteria spread rapidly through the mosquito population and sustain themselves."The ability to genetically engineer Wolbachia could lead to inserting genes that cause the bacteria to produce traits that increase the effectiveness of usingWolbachia against dengue and Zika viruses. It could also be used to combat other agricultural pests," the biologist said.Bordenstein began studying the WO 15 years ago because he was curious about how such a virus survives and flourishes in a symbiotic bacteria like Wolbachiathat has a very small genome. "At the time, some of my colleagues asked why I was studying such an obscure subject," he recalled.Several years ago, Bordenstein and his colleagues felt that they had answered the major scientific questions involving the phage, but they decided to sequence its genome for completeness sake. They had no idea that their analysis would produce information that provides fresh insights in virology and could possibly aid efforts to reduce or eradicate a number of diseases which have afflicted humans for millennia. | Genetically Modified | 2,016 |
October 6, 2016 | https://www.sciencedaily.com/releases/2016/10/161006092903.htm | Research increases by tenfold the mouse mutation resources of one type available to researchers worldwide | The world's supply of one type of mouse mutation available for research increased nearly tenfold with a recent transfer from the UT Southwestern Medical Center laboratory of Nobel Laureate Dr. Bruce Beutler to a repository supported by the National Institutes of Health (NIH) -- a significant contribution that will help further medical and scientific discoveries. | The induced (human-made) germline mouse mutations developed in Dr. Beutler's UT Southwestern laboratory are critical to support genetic research in all mammals, including humans. Germline DNA is the genetic material in egg and sperm cells.Dr. Beutler, Director of the Center for the Genetics of Host Defense at UT Southwestern, transferred the samples to the NIH-supported Mutant Mouse Resource and Research Centers (MMRRC), which collects, distributes, and flash-freezes scientifically valuable, genetically engineered mouse strains and cell lines. The repository, which makes these samples available to researchers worldwide, provides academic researchers with unique genetic models that are unavailable commercially.UT Southwestern President Dr. Daniel K. Podolsky hailed the transfer as part of the institution's bench-to-bedside priority to translate scientific advances into lifesaving, improved patient care."There are many striking similarities between the genomes of the mouse and human, such that some genes have the same effects in both species. This contribution will make these powerful resources available to investigators worldwide to accelerate the discovery of new treatments and means of disease prevention," said Dr. Podolsky, who holds the Philip O'Bryan Montgomery, Jr., M.D. Distinguished Presidential Chair in Academic Administration, and the Doris and Bryan Wildenthal Distinguished Chair in Medical Science. "We are proud that this work has been done on our campus, and we expect that sharing this scientific resource will exert far-ranging impacts across the fields of science and medicine."The estimated 175,000 mutations, cryopreserved in mouse sperm, represent nearly 90 percent of the human-made germline mutations available worldwide, said Dr. Beutler, also Professor of Immunology, a Regental Professor, and holder of the Raymond and Ellen Willie Distinguished Chair in Cancer Research, in Honor of Laverne and Raymond Willie, Sr. The mutations are found in 21,000 genes and include more than 16,000 characterized as "probably null," which to scientists and geneticists means the gene in question is essentially inactivated."Thousands of these null mutations -- which are usually equivalent to a knockout model -- are not available from any other source," Dr. Beutler said.Dr. Beutler's UTSW laboratory was designed for high-throughput mutagenesis and phenotyping, meaning identification of genetic traits based on the interaction of genetics and the environment. The approximately 175,000 transferred mutations are part of the current mutation tally surpassing 265,000 logged on his laboratory's Mutagenetix website, Dr. Beutler said. Professor Chris Goodnow of the Garvan Institute of Medical Research in Sidney, Australia -- a close collaborator of Dr. Beutler and co-recipient of funding from the NIH's National Institute of Allergy and Infectious Diseases (NIAID) -- archived an additional 91,000 induced mutations, which are viewable at the Australian Phenomics Facility.In addition to receiving primary funding from the NIAID, Dr. Beutler also received generous support from several sources, including the Kent and JoAnn Foster Family Foundation for the five-year effort that resulted in creating and characterizing the mutations.The mutagenesis project grew out of his Nobel-prize winning research done at UT Southwestern from 1993 to 1998 exploring the genetics of host defense, meaning when the host, or body, recognizes and responds to infection. One line of defense is the body's innate immune response, which is launched against newly encountered pathogens.A desire to find and understand all the genes and mutations involved in innate immunity led Dr. Beutler to create the Mutagenetix database to characterize every mutation responsible for immune abnormalities in mice and, ultimately, in humans."We are continuing to generate, index, and preserve close to 2,000 new mutations each week, and we would like all of the scientific community to benefit from them," Dr. Beutler said. | Genetically Modified | 2,016 |
September 30, 2016 | https://www.sciencedaily.com/releases/2016/09/160930090224.htm | Genetically engineered crops are safe, review of studies finds | Genetically engineered (GE) crops are no different from conventional crops in terms of their risks to human health and the environment, according to a report published in May 2016 by the U.S. National Academies of Sciences, Engineering, and Medicine. | Leland Glenna, associate professor of rural sociology and science, technology and society in Penn State's College of Agricultural Sciences, served on the committee that authored the report."The study committee found no substantiated evidence of a difference in risks to human health between currently commercialized GE crops -- specifically soybean, maize and cotton -- and conventionally bred crops, nor did it find conclusive cause-and-effect evidence of environmental problems from the GE crops," said Glenna. "These findings should not be interpreted to mean that there are not still many challenges related to both conventional and GE crops, just that currently available GE crops and conventional crops are not different in terms of their risks to human health and the environment."Glenna, a sociologist who studies how social institutions influence scientific research agendas and who, for the past 15 years, has studied the social impacts of agricultural science and technology, noted that GE crops commonly are portrayed either as the solution to social and economic problems or as the cause of them."GE crops are also commonly presented as though there are only two sides to this debate: either you are for them or against them," he said. "But new technologies bring both promises and perils; what seems promising to some might seem perilous to others."However, there is still insufficient research to make conclusive statements on the social and economic impacts of GE crop technologies. I hope that those who read and discuss this report do not shoehorn it into the existing paradigm but, instead, recognize the complexity and nuances of GE crops."The researchers used data published during the last two decades from more than 900 research and other publications to evaluate the positive and negative effects of GE crops -- crops that have been engineered to resist insects or herbicides. The scientists also heard from 80 diverse speakers and read more than 700 comments from members of the public to expand their understanding of GE crop issues.Nearly 180 million hectares of GE crops were planted globally in 2015, roughly 12 percent of the world's planted cropland that year.According to the report, Bt crops, those that contain an insect-resistant gene from the soil bacterium Bacillus thuringiensis, comprise a large segment of GE cropland. The researchers found that from 1996 to 2015, the use of Bt maize and cotton contributed to a reduction in synthetic insecticide use and in crop losses. Some pest-insect populations dropped; however, insect biodiversity increased overall. Insect resistance to Bt proteins was slow to develop only when the crops produced a dose of Bt protein that was large enough to kill insects. Damaging levels of resistance did evolve in some species when resistance-management strategies were not followed.The team found that the use of herbicide-resistant (glyphosate-resistant) crops contributed to greater crop yield by reducing weed pressure. When such crops first were adopted, total kilograms of herbicide applied per hectare of crop per year declined, although the decreases generally have not been sustained. Some weed species have evolved resistance to glyphosate; however, the team noted that delaying such resistance is possible with integrated weed management.To examine the human health effects of GE crops and foods, the team examined animal experimental studies and found a lack of evidence that animals are harmed by eating foods derived from GE crops."Many people are concerned that consuming GE foods may cause cancer, obesity and disorders such as autism spectrum and allergies," Glenna said. "However, the committee examined epidemiological datasets over time from the United States and Canada, where GE food has been consumed since the late 1990s, and similar datasets from the United Kingdom and western Europe, where GE food is not widely consumed. We found no differences among countries in specific health problems."The team also found that economic outcomes of GE crops have been favorable for most producers who have adopted these crops. However, the cost of GE seed may limit the adoption of GE crops by smaller, resource-poor farm holders. Furthermore, economic benefits tend to accrue for early adopters. The team concluded that enduring and widespread use of GE crops will depend on institutional support and access to profitable local and global markets.The report can be downloaded from the National Academies of Sciences, Engineering, and Medicine website: | Genetically Modified | 2,016 |
September 27, 2016 | https://www.sciencedaily.com/releases/2016/09/160927164049.htm | Researchers modify yeast to show how plants respond to a key hormone | Hormones are small signaling molecules that travel between cells and deliver messages to switch on and off specific genes -- affecting behavior, environmental responses and growth. Human hormones include testosterone, insulin and the aptly named growth hormone. Plant hormones are an entirely different set of chemical messengers, which modulate activities such as stem growth, leaf and flower production, root patterning and coping with environmental disruption. | These are just the sorts of tasks that plant biologists seek to understand with precision as the pressure increases to feed a growing population amid unchecked climate change. But hormones in plants affect such a wide variety of genes and plant activities that the fine details of hormone responses are -- at best -- murky.Researchers at the University of Washington have developed a novel toolkit based on modified yeast cells to tease out how plant genes and proteins respond to auxin, the most ubiquitous plant hormone. Their system, described in a paper published Sept. 19 in the Proceedings of the National Academy of Sciences, allowed them to decode auxin's basic effects on the diverse family of genes that plants utilize to detect and interpret auxin-driven messages."Auxin has different messages in different contexts," said senior author and UW biology professor Jennifer Nemhauser. "One cell responds to auxin one way, while its neighbor does the exact opposite -- two different responses from the same chemical. What inside these cells is happening to deliver opposite messages?"As the most widespread plant hormone, auxin affects nearly every aspect of plant biology, including growth, development and stress response. Biologists have long known that auxin acts on stretches of DNA, called promoters, to turn nearby genes on or off. But auxin doesn't simply turn all nearby genes on or off. With auxin, some genes turn on, others are switched off and even more nuanced responses are possible. Plant proteins mediate these varied responses by binding to auxin and then to promoters. Some proteins decrease gene expression, while others do the opposite."There is a large amount of cross-communication between proteins, and plants have a huge number of genes that are targets for auxin," said Nemhauser. "That makes it incredibly difficult to decipher the basic auxin 'code' in plant cells."So Nemhauser's team switched from plant cells to budding yeast -- a single-celled fungus and popular laboratory tool. The researchers engineered yeast cells to express proteins that responded to auxin, so they could measure how auxin modified the on/off state of key plant genes that they also inserted into the cells. In essence, they jury-rigged yeast to respond to auxin. To Nemhauser, this was a simple shift in approach with a potentially huge payoff."We changed the perspective of this problem," said Nemhauser. "By taking the question of auxin response out of plants and reconstructing it -- piece by piece -- in yeast, we were able to find out the parts that matter most."Nemhauser's team could introduce different auxin-response proteins into the modified yeast cells, each time measuring how they modified gene expression in the presence of auxin. Their experiments revealed the basic "code" of auxin signaling -- how specific combinations of repressing or activating proteins can bind to auxin, DNA and one another to affect cellular behavior. For example, their yeast experiments show that the gene-activating protein ARF19 must bind to an identical protein to fully switch on genes. On the other hand, many gene-silencing proteins don't need a partner to switch off genes.These and other simple rules were only shown clearly in the yeast system developed by Nemhauser's team. They shed light on the complex interplay within cells that produces clear auxin-mediated messages."These are a complicated combination of factors within cells that, when interpreted through this interplay, yield sophisticated output signals -- like 'Should this plant invest energy into making leaves or roots?'" said Nemhauser. "And it all begins with this complex dance between auxin and auxin-responding proteins."Nemhauser hopes this yeast-based tool, which she developed with UW electrical engineering professor Eric Klavins, will reveal more details of auxin's actions in plant cells. And she hopes that knowledge will empower both farmers and plant geneticists in their quest to increase crop yields and resilience in the face of droughts and climate change."These tools could do so much, because biological systems are more complex than anything we could engineer," said Nemhauser. "And with the right tools and knowledge of these hormone-signaling pathways, we will know exactly which changes -- minimal and targeted -- will produce desired traits in crops." | Genetically Modified | 2,016 |
September 27, 2016 | https://www.sciencedaily.com/releases/2016/09/160927111446.htm | New switch decides between genome repair, death of cells | The genetic information of every cell is encoded in the sequence of the DNA double helix. Double strand breaks in the DNA, which can be induced by radiation, are a dangerous threat to the cells, and if not properly repaired can lead to cancer. Damaged cells need to decide whether the breaks can be fixed or whether they should be removed by a cellular suicide program called "apoptosis" before initiating cancer. | Björn Schumacher, one of the senior authors, explains: "Within seconds after an harmful incident, different mechanisms start. In a schizophrenic way, the cell starts repairing as well as preparing for apoptosis. We identified an uncharacterized mechanism that integrates signals from the ongoing repair process and the cell death machinery. A protein called UFD-2 forms large complexes at the breaks and verifies whether to proceed with the repair or whether it's time to die." In the process, UFD-2 is a point of intersection that both receives and gives signals.The experiments were performed with the nematode Caenorhabditis elegans. "For our research we used different strains of C. elegans, including wild type and genetically modified ones. They were exposed to ionizing radiation to induce double strand breaks and then examined," says Leena Ackermann, lead author of the study. Schumacher adds: "The results are important to further understand how and why a cell decides to repair or to die. Is the repair still ongoing and successful or is apoptosis necessary? Cells lacking UFD-2 fail to undergo apoptosis. In humans such a situation could lead to a higher risk of a damaged cell becoming a cancer cell."All the proteins that play a part in this mechanism can be found in humans as well, and the findings could be highly relevant to better understanding how DNA damage leads to cancer. DNA damage is also an important driver of the aging process. Although apoptosis protects from cancer, excessive cell death can lead to tissue degeneration and aging. The senior author Thorsten Hoppe originally identified UFD-2 as a key regulator of protein degradation. Here, UFD-2 forms regulatory centers that coordinate DNA repair and cell death. Hoppe hopes for resulting advances in tumor therapy: "The knowledge we gained from this study provides new perspectives for fighting cancer pharmaceutically. It might be possible to manipulate the well-balanced process of apoptosis and protein degradation to make clearance of tumor cells more efficient."The original paper was published on September 26 in | Genetically Modified | 2,016 |
September 16, 2016 | https://www.sciencedaily.com/releases/2016/09/160916110634.htm | Genes essential to life found in mouse mutants are related to many human disease genes | About one-third of all genes in the mammalian genome are essential for life. An international, multi-institutional research collaboration identified, for the first time, mutant traits in the mouse for 52 human disease genes, which significantly contributes to the understanding of the genetic bases for some human diseases, including cardiovascular defects, spina bifida, and metabolic disorders, among many others. The study was published this week in | The group's work is part of the International Mouse Phenotyping Consortium (IMPC), which is generating and assessing the physiological characteristics (phenotyping) of mutations for all of the protein-coding genes in the mouse genome. The Consortium aims to discover new functions for the roughly 20,000 genes mice share with humans and makes all of these mouse strains available to provide a platform for better understanding the mechanisms of human disease. The research team includes investigators from the Perelman School of Medicine at the University of Pennsylvania, The Jackson Laboratory, the Baylor College of Medicine, the University of Toronto, and the MRC Harwell Institute, United Kingdom.The Nature study reports the results of the first 1,700-plus genes characterized by the IMPC, which includes 410 genes, that when mutated on both the maternal and paternal copy, are lethal to the mice and an additional 198 for which fewer than half of the expected number of mutants was identified.This study is set apart by its use of high-throughput imaging with automated analysis to identify novel features that would have easily been missed using older technology. Employing a new, standardized phenotyping pipeline and mouse strains of a single specific genetic background called C57BL/6N, the researchers established both the time of embryo death and the nature of the lethal phenotypes for these lines, discovering many novel phenotypes that shed light on the function of these genes. Incorporation of the high-resolution, three-dimensional imaging and automated, computational analysis of the images allowed the team to rapidly gather detailed data, enabling the discovery of new phenotypes at an unprecedented scale.The Penn team contributed to the bioinformatics analysis of essential genes in humans and showed their relevance to human disease. "The sheer amount of new data reported in this paper is impressive," said co-author Maja Bucan, PhD, a professor of Genetics. "For years, a phenotype for just one knockout mouse would form the basis of a single paper, and this paper includes analysis of 410 knockouts. We compared the genes analyzed in this paper with a list of known human disease genes, which made it possible to identify for the first time the mutant phenotypes in the mouse for 52 human disease genes." Mouse knockouts are genetically modified animals in which an existing gene has been inactivated for the purposes of studying the functions of sequenced genes."When looking across the seven or eight embryos generated for each of the 410 knockouts, we found variations in phenotype at a surprising frequency," said co-author Steve Murray, PhD, senior research scientist at the Jackson Lab. "We expect diversity when we look across different genetic backgrounds, but this is the first large-scale documentation of mice with the same mutation, and otherwise same genetic makeup, that have different individual phenotypes."In addition, in collaboration with the Exome Aggregation Consortium, another large, international DNA-sequencing initiative, the IMPC showed that human versions of mouse essential genes are significantly depleted for harmful mutations in humans. "As a result, we surmise that these essential genes are strong candidates for undiagnosed and rare diseases," said co-first author Xiao Ji, a doctoral student in the Bucan lab.The IMPC calculated that only a small percentage of genes are studied by the broad research community. From this, the systematic approach to phenotyping and unrestricted access to data and mouse models provided by the IMPC promises to fill this large gap in understanding mammalian gene function. All data and images generated by the project are available to researchers, disseminated via an open-source web portal. The mouse models generated are also available to other researchers who may be investigating particular pathways or disease phenotypes. | Genetically Modified | 2,016 |
September 14, 2016 | https://www.sciencedaily.com/releases/2016/09/160914142025.htm | Researcher calls for animal-human embryo research to proceed, but with strong animal protections | In a World View opinion column published in | Insoo Hyun, PhD, associate professor of bioethics, urges such research to proceed only after "knowing the right and wrong ways to treat sentient beings according to complexities of their attributes."Hyun's recommendations appear in the journal's September 15th issue and come a week after the National Institutes of Health closed a month-long public comment period on proposed new regulations, widely expected to be adopted, that would lift a moratorium that currently forbids federal funding for chimera embryo research.For decades, research has taken place on animal-human chimeras (after a Greek mythological figure with the head of a lion, the body of a goat, and the tail of a serpent), without much controversy in the United States, such as in the case of mice transplanted with human cancer cells. However, concerns have arisen about research using human pluripotent stem cells, the focus of the current NIH moratorium. These cells are made from skin or blood cells which are genetically modified to act like embryonic stem cells that can form any adult cell types including human organs.Hyun's recommendations come in response to concerns that the transfer of human stem cells into animal hosts would result in an animal with a human organ with at least partially human moral status, especially if the central nervous system is involved. He writes, however, that "The moral status of humans is not automatically assured by our genetic composition or the physical arrangement of our cells. Rather, it is sustained by a complex of mental traits …" which cannot develop in such chimeras.He notes that chimera studies that involve sentient animals are already tightly regulated via the US Animal Welfare Act and other national and international research policies. He adds, however, that since "the transfer of human stem cells could produce unpredicted effects on the resulting chimeras' equilibria and capacities for suffering, it is crucial that qualified veterinary staff and researchers monitor experiments" and if necessary, apply swift, humane care.Under the NIH's pending proposals, an internal steering committee would provide guidance on chimera research proposals, an approach consistent with new professional guidelines for stem cell research offered by the International Society for Stem Cell Research, which themselves are based on an advisory report which Hyun helped draft.In addition to protecting animals, Hyun notes that "[g]rounding the ethics and regulation of human-animal chimera research in anything other than animal welfare would invite serious practical and philosophical difficulties." He points out that for example, one argument used against transferring human stem cells into animal embryos is that this research is not overseen by animal research committees when it is limited to test-tube experiments. But, he says, the "challenge for these critics … is to explain why animal embryos containing human cells deserve serious consideration of their moral status - enough to potentially rule out their use - when standard human embryos can be used in other projects."The World View column in which Hyun's piece appears is described by | Genetically Modified | 2,016 |
September 12, 2016 | https://www.sciencedaily.com/releases/2016/09/160912161038.htm | Breakthrough in genetic modification of grains | Although the commercialization of transgenic, or "genetically modified," plants has stirred widespread controversy, much research remains focused on improving techniques to create such plants. As people familiar with the controversy likely know, transgenic technology allows breeders to add genes for desirable traits to valuable breeding materials. However, transgenic plants are also widely used in basic scientific research. The ability to add a single gene to a plant allows researchers to explore what that gene does, for instance. | Despite years of effort, it has been remarkably difficult to develop efficient methods for transformation (i.e., genetic modification) of grain crops. The preferred methods generally involve infecting tissue with Agrobacterium -- a bacterium that naturally transfers DNA to its host genome -- and then stimulating that tissue to regenerate into whole plants. However, Agrobacterium infects only a narrow range of grain cultivars, and many cultivars are recalcitrant to regeneration. A paper published in A team of researchers from DuPont added so-called morphogenic genes -- known from basic research to promote the production of embryonic tissue -- to the other genes being transformed (in this case to express green fluorescent protein as a marker of transformation). When they did so, transformation rates increased for a large number of maize cultivars -- in many cases going from essentially no transformation to rates high enough for efficient use in commercial and research applications. The technique also worked in sorghum, rice and sugarcane. This work extends the range of species, cultivars and tissues that can be used for efficient transformation and is a beautiful example of what can be accomplished by combining basic research, technical expertise, and knowledge of practical problems facing mainstream applications. | Genetically Modified | 2,016 |
September 9, 2016 | https://www.sciencedaily.com/releases/2016/09/160909112258.htm | Protein found that initiates DNA repair | Biologists, geneticists, and other scientists who study the cellular processes of aging have long focused on a gene known as sirtuin 6 ( | Now a research team led by Vera Gorbunova and Andrei Seluanov, professors of biology at the University of Rochester, has discovered a protein that may serve as a first responder, activating "We wanted to find how To find out what activates The findings have been published in the journal To communicate stress signals within cells, JNKs add phosphate groups to proteins, and the Rochester study found the amino acid residue on The study is the latest work by Gorbunova and Seluanov to shed light on the molecular mechanisms that drive the aging process. Their previous work involved understanding the prominence of an inferior DNA repair process later in life, as well as how errant DNA fragments -- called jumping genes -- are typically kept inactive.Understanding the molecular, chemical, and genetic process of aging has implications for both longevity and quality of life. While more research and clinical work need to be done, such studies help pave the way for possible treatments in the future.For example, Seluanov says the results may allow pharmaceutical researchers to one day design drugs that activate SIRT6 in ways that reduce molecular damage."These drugs may be used to protect our genomes from damage, and could ultimately prevent cancer and extend healthy lifespan," he says. | Genetically Modified | 2,016 |
September 5, 2016 | https://www.sciencedaily.com/releases/2016/09/160905114756.htm | Was a researcher just served a world first CRISPR meal? | For (probably) the first time ever, plants modified with the "genetic scissors" CRISPR-Cas9 has been cultivated, harvested and cooked. Stefan Jansson, professor in Plant Cell and Molecular Biology at Umeå University, served pasta with "CRISPRy" vegetable fry to a radio reporter. Although the meal only fed two people, it was still the first step towards a future where science can better provide farmers and consumers across the world with healthy, beautiful and hardy plants. | CRISPR (Clustered regularly interspaced short palindromic repeats)-Cas9 is a complicated name for an easy, but targeted, way of changing the genes of an organism. The decisive discovery was published in 2012 by researchers at Umeå University, and the "Swiss army knife of genetic engineering" has been predicted to change the world. With CRISPR-Cas9, researchers can either replace one of the billions of "letters" present in an organism's genome (i.e. the entire gene pool consisting of DNA) or remove short segments, similar to when you edit a written text in a word processor. The technology is called "gene editing" or "genome editing."The first clinical applications are underway; maybe we can soon cure hereditary disease using this technology. However, the situation differs somewhat in the agricultural field. There, the issue is not IF researchers can create plants leading to a more sustainable land management, but rather if these will be allowed in farming. Will plants whose genome has been edited using CRISPR-Cas9 fall under GMO legislation or not? If they do, it makes them illegal to plant in great parts of the world. If not, they will -- just like other plants -- be allowed to be grown at the farmers own discretion.The EU has avoided answering the question, but in November 2015 the Swedish Board of Agriculture interpreted the law as if only a segment of DNA has been removed and no "foreign DNA" has been inserted, it is not to be regarded as a genetically modified organism -- a GMO. That also means that the plant can be cultivated without prior permission. In spring 2016, American authorities stated that they agreed. The organism in question there was a mushroom who had lost the part of its DNA that made it go brown. This opens up for using the technology to develop plants of the future.This summer has been the first time that plants that have been gene-edited using CRISPR-Cas9 -- in a way that does not classify the plant as GMO -- have been allowed to be cultivated outside of the lab. This is definitely the first time in Europe, and even if it been done before in other parts of the world, it has been kept secret. This time, it was a cabbage plant and the Radio Sweden gardening show "Odla med P1" took part in the harvest leading to the probably first-ever meal of CRISPR-Cas9 genome-edited plants. The first CRISPR meal to have been enjoyed was "Tagliatelle with CRISPRy fried vegetables.""The CRISPR-plants in question grew in a pallet collar in a garden outside of Umeå in the north of Sweden and were neither particularly different nor nicer looking than anything else," says plant scientist Stefan Jansson. But they represent both a new phase of agriculture where scientific advances will be implemented in new plant species and that to a small or large extent will be made available to farmers across the world. In other words: a meal for the future. | Genetically Modified | 2,016 |
September 2, 2016 | https://www.sciencedaily.com/releases/2016/09/160902142228.htm | Placenta in females, muscle mass in males: Dual heritage of a virus | It was already known that genes inherited from ancient retroviruses[1] are essential to the placenta in mammals, a finding to which scientists in the | Retroviruses carry proteins on their surface that are able to mediate fusion of their envelope with the membrane of a target cell. Once released inside that cell, their genetic material becomes integrated in the host's chromosomes. In the rare cases where the infected cell is involved in reproduction, the viral genes may be transmitted to progeny. Thus nearly 8% of the mammalian genome is made up of vestiges of retroviruses, or "endogenous" retroviruses. Most of them are inactive, but some remain capable of producing proteins: this is the case of syncytins, proteins that are present in all mammals and encoded by genes inherited from retroviruses "captured" by their ancestors. A little more than five years ago, and thanks to inactivation of these genes in mice, the team led by Thierry Heidmann demonstrated that syncytins contribute to formation of the placenta. Because of their ancestral ability to mediate cell-cell fusion they give rise to the syncytiotrophoblast[3], a tissue formed by the fusion of a large number of cells derived from the embryo, at the fetomaternal interface.Using the same mice, the team has revealed a "collateral" and unexpected effect of these proteins: they endow males with more muscle mass than females! Like the syncytiotrophoblast, muscle mass develops from fused stem cells. In the genetically-modified male mice, these fibers were 20% smaller and displayed 20% fewer nuclei than in standard males; they were then similar to those seen in females, as was their total muscle mass. It therefore appears that the inactivation of syncytins leads to a fusion deficit during muscle growth, but only in males. The scientists observed the same phenomenon in the case of muscle regeneration following a lesion: the male mice incapable of producing syncytins experienced less effective regeneration than the other males, but it was comparable to that seen in females. Furthermore, the regenerating muscle fibers produced syncytin -- once again, only in males.If this discovery were to be confirmed in other mammals, it might account for the muscle dimorphism observed between males and females, a difference that is not seen so systematically in egg laying animals. By cultivating muscle stem cells from different mammalian species (mouse, sheep, dog, human), the scientists have advanced some way along the path: they indeed showed that syncytins contributed to the formation of muscle fibers in all the species tested. It is now necessary to demonstrate whether, in these species as well, the action of syncytins is also male-specific.[1] The particular feature of retroviruses is that they possess an enzyme that permits transcription of their RNA genome in a "complementary" DNA molecule which is able to integrate in the DNA of the host cell. The AIDS virus (HIV) is the best known example of a retrovirus.[2] In collaboration with colleagues working on muscles: the teams led by Julie Dumonceaux at the Centre de Recherche en Myologie (CNRS/UPMC/Inserm) and Laurent Tiret at the École Nationale Vétérinaire d'Alfort and the Institut Mondor de Recherche Biomédicale (Inserm/UPEC).[3] The syncytiotrophoblast is part of the placenta that permits implantation in the uterus and then constitutes the interface between the maternal bloodstream and that of the embryo, where the exchanges of gases and nutrients necessary for the latter's development occur. | Genetically Modified | 2,016 |
September 1, 2016 | https://www.sciencedaily.com/releases/2016/09/160901125246.htm | It's a boy: Controlling pest populations with modified males | Populations of New World screwworm flies -- devastating parasitic livestock pests in Western Hemisphere tropical regions -- could be greatly suppressed with the introduction of male flies that produce only males when they mate, according to new research from North Carolina State University, the USDA's Agricultural Research Service, the Panama-United States Commission for the Eradication and Prevention of Screwworm (COPEG) and the Smithsonian Tropical Research Institute. | Withholding tetracycline in the larval diet essentially means "It's a boy" when the genetically modified male flies successfully mate with females in the field, says Max Scott, an NC State entomologist who is the corresponding author of a paper describing the research."Genetic suppression of a pest population is more efficient if only males survive, so we manipulated screwworm genes to promote a female-lethal system that works when a common antibiotic is not provided at larval stages," Scott said. "If we feed the larvae the antibiotic both male and female survive and are as fit as the wild type strain."The study shows that the genetically modified males both compete well for the attention of fertile females and mate successfully with fertile females. The genetically modified flies also do not mate with other very closely related fly species.New World screwworm flies (Scott says that a sterile insect technique has been used to keep the South American flies at bay. This technique involves irradiating both male and female flies to make them sterile and then releasing them -- in an area between the Panama Canal and Colombia -- to mate with fertile flies in order to prevent screwworm re-introduction to Central and North America."This is a bit inefficient, as sterile males will mate with sterile females, which is totally unnecessary," Scott says. "Releasing only males, would cut down on the costs of rearing sterile female flies and should significantly increase the efficiency of the suppression program. Plus, it would take fewer resources to begin screwworm eradication program in other afflicted areas, like the west coast of South America, for example." In addition, the technology should be easily transferable to other flies that are pests of livestock such as the Old World screwworm.Scott added that COPEG will now evaluate one of the genetically modified screwworm fly lines. That commission has worked to prevent the reintroduction of the pest into North and Central America and is responsible for the current sterile insect technique program. All of the genetically modified strains were developed within the COPEG biosecure facility in Panama, which will facilitate incorporation of the strains into the ongoing operational program.The study was published online in the journal | Genetically Modified | 2,016 |
August 31, 2016 | https://www.sciencedaily.com/releases/2016/08/160831142856.htm | Forensic DNA analysis checks the origin of cultured cells | Cell lines are cultured cells that are commonly used in medical research. New results from Uppsala University show that such cells are not always what they are assumed to be. Using genetic analyses, the researchers showed that a commonly used cell line which was established in Uppsala, Sweden, almost fifty years ago does not originate from the patient it is claimed to stem from. The findings are published in the journal | A cell line consists of cultured cells that often originate from a tumor. In contrast to other cultured cells, such tumor cells can divide indefinitely and a cell line can therefore be cultured for many years. It is also easy to study, simple to handle and results can be obtained with high reproducibility. Cell lines are therefore indispensable in medical research and a large number of cell lines exist that originate from many different tumor types.Researchers studying the brain tumor type glioma often use a cell line called U87MG that was established at Uppsala University almost fifty years ago. It is presently publicly available from the American Type Culture Collection (ATCC), where researchers can order it to use it in their studies. Bengt Westermark is senior professor at the Department of Immunology, Genetics and Pathology, which is the present name for the department where U87MG was established. His research group has often used the original U87MG line and their experience led them to question the authenticity of the ATCC cell line.Marie Allen, an expert in DNA fingerprinting, works at the same department. DNA fingerprinting is an important tool for determining genetic identity, for instance in crime scene investigations.'Marie and her colleagues helped us genetically compare the cell lines with each other. We found that the U87MG cell line from ATCC had a different DNA profile than the original cell line in Uppsala', says Bengt Westermark.When the cell line was established in the 1960s, material from the original tumor was saved as thin sections on microscope slides. Using a very sensitive DNA analysis technique that can also be employed when only very small amounts of DNA from old tissue are available, the researchers could compare the two current cell lines with the tumor from which the cell line was established.'The comparison showed that the Uppsala cell line was genetically identical with the original tumor whereas the U87MG cell line from ATCC had a different, unknown origin. We don't know at which point during the fifty years of culturing the mix-up occurred but we have been able to show that the ATCC U87MG line is most likely from a human glioma tumor', says Bengt Westermark.Many scientific journals require researchers who report results based on cell line experiments to use DNA profiling to establish the identity of the used cells. The new findings show that proper identification of a cell line also requires that the DNA profile matches the tissue of origin. This is essential if one wants to claim that the cells, and thereby the research results, are true representatives of the original tumor. | Genetically Modified | 2,016 |
August 30, 2016 | https://www.sciencedaily.com/releases/2016/08/160830083807.htm | More tomatoes, faster: Accelerating tomato engineering | Tomatoes are already an ideal model species for plant research, but scientists at the Boyce Thompson Institute (BTI) just made them even more useful by cutting the time required to modify their genes by six weeks. | While looking for ways to make tomatoes and other crop plants more productive, BTI Assistant Professor Joyce Van Eck and former postdoctoral scientist Sarika Gupta developed a better method for "transforming" a tomato -- a process that involves inserting DNA into the tomato genome and growing a new plant. By adding the plant hormone auxin to the medium that supports growth of tomato cells, they can speed up the plant's growth, ultimately accelerating the pace of their research. They describe this advance in a study published in Typically, transformation works by using a soil bacterium called Agrobacterium tumefaciens to insert a new segment of DNA into the cells of tomato seedling tissues. The transformed cells are transplanted onto plant regeneration medium, which contains nutrients and hormones that cause the tissue to grow into a tiny new plant. These plantlets are then transferred to root induction medium where they grow roots, before being planted in soil and hardened in the greenhouse. In the new method, the Van Eck lab adds auxin to the regeneration and rooting media. The addition reduces the length of the procedure from 17 weeks to just 11."If you can speed up the plant development, which is what the auxin is doing, you can decrease the time it takes to get genetically engineered lines," said Van Eck.Researchers in the Van Eck lab perform tomato transformations routinely, as a research method to understand how individual genes affect tomato growth and development. Their new protocol not only saves time, but uses fewer materials, and saves money. The researchers can then finish experiments sooner and potentially run more projects at once.The project came out of a collaboration with Cold Spring Harbor Laboratory to identify gene pathways that could be used to breed crops with higher yields."We're looking at the genes and gene networks involved in stem cell proliferation, meristem development and flowering and branching," said Van Eck, "with the end goal being that maybe genes that we identify in tomato, which is strictly being used as a model, might help us understand what can be done to increase yield in other crops." | Genetically Modified | 2,016 |
August 18, 2016 | https://www.sciencedaily.com/releases/2016/08/160818145954.htm | Modifying a living genome with genetic equivalent of 'search and replace' | Researchers including George Church have made further progress on the path to fully rewriting the genome of living bacteria. Such a recoded organism, once available, could feature functionality not seen in nature. It could also make the bacteria cultivated in pharmaceutical and other industries immune to viruses, saving billions of dollars of losses due to viral contamination. | Finally, the altered genetic information in such an organism wouldn't be able to contaminate natural cells because of the code's limitations outside the lab, researchers say, so its creation could stop laboratory engineered organisms from genetically contaminating wildlife. In the DNA of living organisms, the same amino acid can be encoded by multiple codons -- DNA "words" of three nucleotide letters.Here, building on previous work that demonstrated it was possible to use the genetic equivalent of "search and replace" in The researchers attempted to reduce the number of codons in the Though they did not achieve a fully operational 57-codon | Genetically Modified | 2,016 |
August 16, 2016 | https://www.sciencedaily.com/releases/2016/08/160816182622.htm | Genetically modified soil bacteria work as electrical wires | Scientists sponsored by the Office of Naval Research (ONR) have genetically modified a common soil bacteria to create electrical wires that not only conduct electricity, but are thousands of times thinner than a human hair. | As electronic devices increasingly touch all facets of people's lives, there is growing appetite for technology that is smaller, faster and more mobile and powerful than ever before. Thanks to advances in nanotechnology (manipulating matter on an atomic or molecular scale), industry can manufacture materials only billionths of a meter in thickness.The ONR-sponsored researchers -- led by microbiologist Dr. Derek Lovley at the University of Massachusetts Amherst -- say their engineered wires can be produced using renewable "green" energy resources like solar energy, carbon dioxide or plant waste; are made of non-toxic, natural proteins; and avoid harsh chemical processes typically used to create nanoelectronic materials."Research like Dr. Lovley's could lead to the development of new electronic materials to meet the increasing demand for smaller, more powerful computing devices," said Dr. Linda Chrisey, a program officer in ONR's Warfighter Performance Department, which sponsors the research. "Being able to produce extremely thin wires with sustainable materials has enormous potential application as components of electronic devices such as sensors, transistors and capacitors."The centerpiece of Lovley's work is Geobacter, a bacteria that produces microbial nanowires -- hair-like protein filaments protruding from the organism -- enabling it to make electrical connections with the iron oxides that support its growth in the ground. Although Geobacter naturally carries enough electricity for its own survival, the current is too weak for human use, but is enough to be measured with electrodes.Lovley's team tweaked the bacteria's genetic makeup to replace two amino acids naturally present in the wires with tryptophan -- which is blamed (incorrectly, some say) for the sleepiness that results from too much Thanksgiving turkey. Food allegations aside, tryptophan actually is very good at transporting electrons in the nanoscale."As we learned more about how the microbial nanowires worked, we realized it might be possible to improve on nature's design," said Lovley. "We rearranged the amino acids to produce a synthetic nanowire that we thought might be more conductive. We hoped that Geobacter might still form nanowires and double their conductivity."The results surpassed the team's expectations as the synthetic, tryptophan-infused nanowires were 2,000 times more conductive than their natural counterparts. And they were more durable and much smaller, with a diameter of 1.5 nanometers (over 60,000 times thinner than a human hair) -- which means that thousands of nanowires could possibly be stored in the tiniest spaces.Lovley and Chrisey both say these ultra-miniature nanowires have numerous potential applications as electronic and computing devices continue to shrink in size. For example, they might be installed in medical sensors, where their sensitivity to pH changes can monitor heart rate or kidney function.From a military perspective, the nanowires could feed electrical currents to specially engineered microbes to create butanol, an alternative fuel. This would be particularly useful in remote locations like Afghanistan, where fuel convoys are often attacked and it costs hundreds of dollars per gallon to ship fuel to warfighters.Lovley's nanowires also may play a crucial role in powering highly sensitive microbes (which could be placed on a silicon chip and attached to unmanned vehicles) that could sense the presence of pollutants, toxic chemicals or explosives."This is an exciting time to be on the cutting edge of creating new types of electronics materials," said Lovley. "The fact that we can do this with sustainable, renewable materials makes it even more rewarding."Lovley's research is part of ONR's efforts in synthetic biology, which creates or re-engineers microbes or other organisms to perform specific tasks like improving health and physical performance. The field is a top ONR research priority because of its potential far-ranging impact on warfighter performance and fleet capabilities. | Genetically Modified | 2,016 |
August 5, 2016 | https://www.sciencedaily.com/releases/2016/08/160805115212.htm | Microscopic collisions help proteins stay healthy | Studies at The University of Texas Health Science Center at San Antonio are providing basic new understanding about "heat shock proteins," also called "chaperone proteins." These proteins, first identified in cells subjected to heat, are very important under many stressful and non-stressful metabolic conditions. They maintain proper protein function and, importantly, prevent the inappropriate accumulation of damaged proteins. For example, accumulation of damaged proteins such as beta amyloid, tau and synuclein are thought to be very important in the development of diseases of the brain such as Alzheimer's disease and Parkinson's disease. | Aug. 1 in the journal "No one knew how the heat shock proteins pull apart bad protein complexes," Dr. Sousa said. "At the molecular level, everything is moving, colliding and bumping, and smashing into other components of the cells. We found that the system moves Hsp70s to where they are needed. Once this occurs, collision pressures pull things apart."Previous attempts to glean this information failed because the proteins studied were too heterogeneous -- of too many different sizes, shapes and actions -- to isolate the Hsp70 behavior.The UT Health Science Center team studied clathrin, a protein that is uniform in size and shape and is important in making intracellular cages that transport other proteins. Previously clathrin was only available from animal specimens, making it very difficult to manipulate experimentally. Dr. Lafer made a technical breakthrough when she was able to grow clathrin in bacteria for the first time using recombinant DNA technology. The clathrin could then be genetically engineered for mechanistic studies.Dr. Lafer grew clathrin "cages" -- shaped like microscopic soccer balls -- that provided the biological raw material for Dr. Sousa and the team to study the force that occurs with Hsp70 collisions. The clathrin model system could be manipulated to yield precise results.Dr. Sousa gave this analogy of the study: The heat shock protein is like a worker with an ax who, when moved to a wood pile, begins swinging. The wood pile represents a protein complex. The scientists give the worker both thick trees and thin trees to swing at, and spindly wood and hard wood. They change the angle of the wood pile, and every other variable, to learn how this affects the chopping.By making variants of clathrin with recombinant DNA technology, team members were able to manipulate this biological material in ways that allowed them to determine the mechanism by which it is taken apart by Hsp70."This work was a tour de force, requiring the convergence of exceptional biochemical and molecular genetic skills with a deep understanding of the principles of physical chemistry," said Bruce Nicholson, Ph.D., chair of the Department of Biochemistry at the Health Science Center. "Such insights into the most basic aspects of protein chemistry and cell biology are often, as in this case, driven by a curiosity to find out how the molecular machines that drive our bodies work. But from these basic pursuits of scientific curiosity will often stem great benefits to human health."Understanding Hsp70 behavior may have relevance to human disease. By increasing Hsp70 function, scientists cured Huntington's, a neurodegenerative disease, in a fly model. Cancer is another interesting focus. Tumors rely on Hsp70s to survive, so lowering Hsp70 function is a topic in cancer research."This is an impressive study that not only improves our understanding of cellular biology, but could lead to therapeutic discoveries for neurodegenerative diseases," said Francisco González-Scarano, M.D., dean of the School of Medicine and executive vice president for medical affairs of the Health Science Center. "It is a tribute to scientists who ask hard questions and develop tools to answer them. My congratulations to the team.""We attacked this problem because it was a really important question in cellular biology," Dr. Lafer said. "We didn't do it because we wanted to cure neurodegenerative disease or cancer. We know, however, that when we attack really important questions in science and biology, it ultimately leads to translational applications down the line.""Sometimes as a scientist you just increase understanding of the way the world works," Dr. Sousa said. "This is something scientists have wanted to know." | Genetically Modified | 2,016 |
August 4, 2016 | https://www.sciencedaily.com/releases/2016/08/160804152725.htm | Biofuel production technique could reduce cost, antibiotics use | The cost and environmental impact of producing liquid biofuels and biochemicals as alternatives to petroleum-based products could be significantly reduced, thanks to a new metabolic engineering technique. | Liquid biofuels are increasingly used around the world, either as a direct "drop-in" replacement for gasoline, or as an additive that helps reduce carbon emissions.The fuels and chemicals are often produced using microbes to convert sugars from corn, sugar cane, or cellulosic plant mass into products such as ethanol and other chemicals, by fermentation. However, this process can be expensive, and developers have struggled to cost-effectively ramp up production of advanced biofuels to large-scale manufacturing levels.One particular problem facing producers is the contamination of fermentation vessels with other, unwanted microbes. These invaders can outcompete the producer microbes for nutrients, reducing yield and productivity.Ethanol is known to be toxic to most microorganisms other than the yeast used to produce it, Saccharomyces cerevisiae, naturally preventing contamination of the fermentation process. However, this is not the case for the more advanced biofuels and biochemicals under development.To kill off invading microbes, companies must instead use either steam sterilization, which requires fermentation vessels to be built from expensive stainless steels, or costly antibiotics. Exposing large numbers of bacteria to these drugs encourages the appearance of tolerant bacterial strains, which can contribute to the growing global problem of antibiotic resistance.Now, in a paper published today in the journal The researchers engineered microbes, such as What's more, because the engineered strains only possess this advantage when they are fed these unconventional chemicals, the chances of them escaping and growing in an uncontrolled manner outside of the plant in a natural environment are extremely low."We created microbes that can utilize some xenobiotic compounds that contain nitrogen, such as melamine," Stephanopoulos says. Melamine is a xenobiotic, or artificial, chemical that contains 67 percent nitrogen by weight.Conventional biofermentation refineries typically use ammonium to supply microbes with a source of nitrogen. But contaminating organisms, such as Lactobacilli, can also extract nitrogen from ammonium, allowing them to grow and compete with the producer microorganisms.In contrast, these organisms do not have the genetic pathways needed to utilize melamine as a nitrogen source, says Stephanopoulos."They need that special pathway to be able to utilize melamine, and if they don't have it they cannot incorporate nitrogen, so they cannot grow," he says.The researchers engineered When they experimented with a mixed culture of the engineered They then investigated engineering the yeast SThe engineered strain was then able to grow with cyanamide as its only nitrogen source.Finally, the researchers engineered both Like the engineered "So by engineering the strains to make them capable of utilizing these unconventional sources of phosphorus and nitrogen, we give them an advantage that allows them to outcompete any other microbes that may invade the fermenter without sterilization," Stephanopoulos says.The microbes were tested successfully on a variety of biomass feedstocks, including corn mash, cellulosic hydrolysate, and sugar cane, where they demonstrated no loss of productivity when compared to naturally occurring strains.The ROBUST strategy is now ready for industrial evaluation, Shaw says. The technique was developed with Novogy researchers, who have tested the engineered strains at laboratory scale and trials with 1,000-liter fermentation vessels, and with Felix Lam of the MIT Whitehead Institute for Biomedical Research, who led the cellulosic hydrosylate testing.Novogy now hopes to use the technology in its own advanced biofuel and biochemical production, and is also interested in licensing it for use by other manufacturers, Shaw says. | Genetically Modified | 2,016 |
August 2, 2016 | https://www.sciencedaily.com/releases/2016/08/160802172614.htm | What’s changed in genetics since your high school biology class? | The field of genetics has seen astonishing breakthroughs and the development of world-changing technologies in the past half century. With such rapid progress, the field has likely raced well beyond the high school biology textbook your class used to study alleles, fruit flies and eye color inheritance. | Joel Eissenberg, Ph.D., associate dean for research and professor of biochemistry and molecular biology at Saint Louis University School of Medicine, shares a recap to get up to speed on the remarkable advances that are changing not only science and medicine, but also fields like forensics and ancestry.Over the course of the last few decades, advances in genetics have shed light on inherited diseases, cancer, personalized medicine, genetic counseling, the microbiome, diagnosis and discovery of viruses, taxonomy of species, genealogy, forensic science, epigenetics, junk DNA, gene therapy and gene editing.From Angelina Jolie's proactive surgical strategy upon learning she carries BRCA cancer genes to Harvard University's project to bring back woolly mammoth traits, Jurassic Park-style, to millions learning about their ancestry through genetic testing, technologies using principles of genetics now surround us.Whether you're foggy on the concept of "epigenetics" or just want to recap the high points of the science of genetics, check out Eissenberg's overview of some of the most exciting advances in the last 50 years: Discoveries in DNA: What's New Since You Went to High School?If you took high school biology in the …Further information: | Genetically Modified | 2,016 |
July 29, 2016 | https://www.sciencedaily.com/releases/2016/07/160729132937.htm | Vaccination: Zika infection is caused by one virus serotype | Vaccination against a single strain of Zika virus should be sufficient to protect against genetically diverse strains of the virus, according to a study conducted by investigators from the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH); Washington University in St. Louis; and Emory University in Atlanta. | Zika virus strains are grouped into two distinct genetic lineages: African and Asian. The Zika virus strain circulating in the current outbreak affecting Central and South America and the Caribbean is of the Asian lineage. When individuals are infected with Zika virus, their immune systems produce neutralizing antibodies to fight the infection. These antibodies may offer immunity against future infections by strains of the same Zika virus lineage. Until now, it was unclear whether the antibodies could also protect against infection with strains of the other Zika virus lineage. Results from laboratory experiments and tests in mice now show this may be possible. Such protection indicates that, despite being genetically distinct, all strains of Zika virus have identical surface antigens and therefore are the same serotype. The closely-related Dengue virus has four serotypes, which is why people can be infected with dengue as many as four times, once with each serotype.In this study, scientists took serum samples from people infected by Zika virus strains circulating in South America and mixed them with multiple strains of the virus in the laboratory to see how well the serum antibodies neutralized the virus. Results showed that antibodies elicited after infection with Zika virus strains of the Asian lineage were able to potently inhibit both Asian lineage and African lineage strains. The researchers conducted similar experiments using serum samples from mice and found that sera from mice infected with either Asian or African Zika virus strains were equally effective in neutralizing virus strains from either lineage.The findings are important to the ongoing effort to rapidly develop a preventive Zika vaccine, according to the authors. Because there is only one Zika virus serotype, antibodies elicited by any Zika virus strain in a vaccine could conceivably confer protection against all Zika virus strains, the researchers conclude. | Genetically Modified | 2,016 |
Subsets and Splits