Zimberknopf E.,Centro Universitario Da Fundacao Of Ensino Octavio Bastos |
Xavier G.F.,Biosciences Institute |
Kinsley C.H.,University of Richmond |
Felicio L.F.,University of Sao Paulo
Comparative Medicine | Year: 2011
Reproductive experience in female rats modifies acquired behaviors, induces long-lasting functional neuroadaptations and can also modify spatial learning and memory. The present study supports and expands this knowledge base by employing the Morris water maze, which measures spatial memory. Age-matched young adult (YNG) nulliparous (NULL; nonmated) and primiparous (PRIM; one pregnancy and lactation) female rats were tested 15 d after the litter's weaning. In addition, corresponding middle-aged (AGD) PRIM (mated in young adulthood so that pregnancy, parturition, and lactation occurred at the same age as in YNG PRIM) and NULL female rats were tested at 18 mo of age. Behavioral evaluation included: 1) acquisition of reference memory (platform location was fixed for 14 to 19 d of testing); 2) retrieval of this information associated with extinction of the acquired response (probe test involving removal of the platform 24 h after the last training session); and 3) performance in a working memory version of the task (platform presented in a novel location every day for 13 d, and maintained in a fixed location within each day). YNG PRIM outperformed NULL rats and showed different behavioral strategies. These results may be related to changes in locomotor, mnemonic, and cognitive processes. In addition, YNG PRIM exhibited less anxiety-like behavior. Compared with YNG rats, AGD rats showed less behavioral flexibility but stronger memory consolidation. These data, which were obtained by using a welldocumented spatial task, demonstrate long lasting modifications of behavioral strategies in both YNG and AGD rats associated with a single reproductive experience. Copyright 2011 by the American Association for Laboratory Animal Science.
News Article | March 2, 2017
Researchers at the University of Arkansas recently took a step toward answering a question for the ages: Is there life on Mars? Answer: they can’t rule it out. Two recent publications suggest that life, in the form of ancient, simple organisms called methanogens, could survive the harsh conditions found near the surface of Mars, and deep in its soils. Using methanogens to test for survivability is particularly relevant because scientists have detected their byproduct, methane, in the Martian atmosphere. On Earth, methane is strongly associated with organic matter, though there are non-organic sources of the gas, including volcanic eruptions. Scientists aren’t yet sure what the presence of Martian methane means. But one possibility is that tenacious life flourishes on Mars despite the rocky soil, thin atmosphere and scarcity of liquid water. “We consider methanogens ideal candidates for possible life on Mars because they are anaerobic, and non-photosynthetic, meaning that they could exist in the subsurface,” said Rebecca Mickol, a Ph.D. candidate at the Arkansas Center for Space and Planetary Science. “Just a few millimeters of Martian regolith is enough to protect the organisms from the dangerous UV and cosmic radiation that hits the surface. Additionally, methane has been detected in the Martian atmosphere, via multiple space-based and ground-based sources, including the Martian rover, Curiosity. Although these findings are still controversial, the presence of methane on Mars is particularly exciting because most methane on Earth is biological in origin.” Mickol is the lead author on a study titled “Low Pressure Tolerance by Methanogens in an Aqueous Environment: Implications for Subsurface Life on Mars,” published in September in the journal Origins of Life and Evolution of Biospheres. Using the planetary simulator at the University’s W.M. Keck Laboratory, Mickol and her team subjected four species of methanogens to the low atmospheric pressure that would exist in a Martian subsurface liquid aquifer. All four survived the exposure for between three and 21 days. The underlying idea, Mickol said, is that life is found almost everywhere on Earth, so it’s not out of the question to find it thriving in harsh conditions elsewhere. “The prevalence of life on Earth, in all kinds of ‘extreme’ environments, and the fact that life arose fairly early on in Earth's history, makes it hard to believe there isn't some sort of microscopic life on the other planets and moons in our solar system,” she said. Pradeep Kumar, an assistant professor in the Physics Department, is looking at the implications for life deeper on Mars: as far down as 30 kilometers — more than 18 miles — under the planet’s surface. Geothermal models suggest that liquid water could exist at that depth, though it would be under extreme pressure and at high temperature. Nonetheless, water is essential to life as we know it, so researchers base their assumptions on where it might be found. On Earth, methanogens that survive in hydrothermal environments do so despite a wide range of pressures, pH levels and temperatures. In the test, funded by a grant from the Arkansas Biosciences Institute, sKumar and his team — grad students Navita Sinha and Sudip Nepal of the Center for Space Planetary Sciences and the Microelectronics and Photonics department, respectively; and Timothy Kral, a professor in the Department of Biological Sciences – used a hydrostatic chamber and generated atmospheric pressures as high as 1,200 times that found on the surface. They held temperatures at 55 degrees centigrade, about 131 degrees Fahrenheit, and varied pH levels from 4.96 to 9.13. (A pH level of 7.0 is neutral, below that is considered acidic and above is considered alkaline.) The results, published in February the journal Planetary and Space Science, show that the methanogen M. wolfeii, one the species Mickol experimented with, survived all pressure and pH levels. In acidic conditions, its growth rate increased with higher pressures. In neutral and alkaline conditions, the growth rate increased initially, then decreased with higher pressures. “Given the discovery of methane in Martian atmosphere, our study raises an exciting possibility of methanogenic archaea to be a viable organism that can survive and possibly thrive in the subsurface conditions of Mars,” Kumar said. The search for life on Mars continues. At the very least, we know it could be there.
News Article | February 15, 2017
The scallop is one of the largest edible molluscs, and gourmets consider it to be a great delicacy. To meet this demand, the fishing industry cultivates these shellfish in coastal aquafarms. In a new analysis, behavioural ecologists at Bielefeld University have confirmed that cultivated scallops developed their own genetic structure that differs from that of natural scallops. The biologists studied a total of nine populations of scallops (Pecten maximus) along the coast of Northern Ireland. They are presenting their results this Wednesday (8.2.2017) in the research journal 'Royal Society Open Science'. 'Of the nine scallop populations studied, only one shows a marked genetic difference from the others and that is the artificially cultivated type,' reports Joseph I. Hoffman, head of the Molecular Behavioural Ecology research group. New breeds are cultivated in, for example, mesh cages in coastal waters. Now and then, young scallops escape through the mesh and are thereby able to impact on natural populations. Biologists use the term population to describe a group of organisms of one species that live together in one area and are linked together genetically through reproduction over successive generations. The researchers analysed the genetic architecture of the mollusc populations. 'Studying the genetic architecture of animal populations helps us to understand which external appearance an organism can adopt - for example, how large a mollusc can become or whether it can develop red streaks on its surface,' says David Vendrami. The doctoral student has analysed a total of 180 mollusc samples. The Agri-Food and Biosciences Institute in Belfast (Northern Ireland) collected these in February 2015 during an excursion along the Northern Irish Atlantic coast. The researchers have not just confirmed how breeding affects scallop populations. Their study also confirms that these molluscs adapt their shape and internal colouring very flexibly to conditions in their environment, and that they do this independently of whether they belong to the one cultivated or the eight natural populations. 'We have tested how far genes relate to appearance. However, that is very probably not the case. It is highly likely that the external characteristics of the molluscs depend on their surroundings,' says Vendrami. Scientists at Bielefeld also used this study to compare a classical DNA analysis with a new procedure. The classical analysis proceeds by evaluating repeated short DNA sequences (microsatellites) in order to compare samples from different organisms. The modern procedure (RAD sequencing) takes less time to analyse thousands of times more DNA sequences. 'The new procedure is markedly better at finding differences in the populations than the classical approach,' says David Vendrami. In their future research, Hoffman, Vendrami, and their colleagues will be going beyond Northern Ireland and studying samples along the entire Atlantic coast from Norway to Portugal as well as in the Mediterranean. Their aim is to find out how scallops as well as other crustaceans react to different environmental conditions in terms of their growth. For the current study, researchers at Bielefeld cooperated with a series of partners: the University of Cambridge (England), der University of Duisburg-Essen, the British Antarctic Survey research institute (Cambridge), and the Agri-Food and Biosciences Institute in Belfast (Northern Ireland). David Vendrami is a member of the Marie Sk?odowska-Curie action 'Calcium in a Changing Environment' (CACHE) in which ten doctoral students of different disciplines from all over Europe are studying Europe's commercially most important molluscs. The action is being funded by the European Union. Marie Sk?odowska-Curie actions are part of the European Union's Framework Programme for Excellent Research and Innovation. David L. J. Vendrami, Luca Telesca, Hannah Weigand, Martina Weiss, Katie Fawcett, Katrin Lehman, Melody S. Clark, Florian Leese, Carrie McMinn, Heather Moore, Joseph I. Hoffman: RAD sequencing resolves fine-scale population structure in a benthic invertebrate: implications for understanding phenotypic plasticity. Royal Society Open Science, http://dx. , published on the 8th of February 2017.
News Article | November 18, 2015
In a pasture outside Edmonton, Canada, you’ll find a few dozen cows doing what cows do: mostly eating. The average animal spends eight-plus hours a day filling its belly, or as is the case with cows, bellies. Along with that enormous appetite, cows are born with the ability to digest almost any plant they can chew, thanks to a multichambered stomach and a helpful army of gut microbes that break down food that most mammals cannot. The system is an evolutionary bonanza for cattle, but it’s not so easy on the environment — which is why the animals at the Lacombe Research Centre are no ordinary grazers. Through a transponder clipped to the ear of each cow, scientists record when a cow sticks her head into a bin of tasty feed pellets. As she eats, a solar-powered fume hood above captures her exhalations. Laser beams surround the pasture, reading gases in the atmosphere. Livestock is a major source of methane emissions from human activity in the United States. The gas is produced as part of the digestive process of cattle and other ruminants and from microorganisms that grow in manure (numbers in chart at top are rounded). Source: Inventory of U.S. greenhouse gas emissions and sinks: 1990–2013/EPA 2015 All this fuss is over bovine burps. While cattle and other ruminants like sheep and goats have been gassy for around 50 million years, scientists have only recently begun to pay keen attention to their exhaust as concern grows over climate change. The belches contain methane, an odorless compound that is the main component of natural gas. In the atmosphere, methane warms the Earth. It isn’t the most abundant greenhouse gas created by human activity (that prize goes to carbon dioxide), but methane is one of the most powerful at trapping heat. In a “pound for pound” comparison, over a century, methane has an impact on climate change that is 25 times as great as CO , according to the U.S. Environmental Protection Agency. Citing methane’s impact, a recent CNN story referred to beef as “the new SUV.” But the old SUVs, along with the rest of the oil and gas industry, are a larger source of atmospheric methane in the United States, EPA data indicate, contributing 29 percent of U.S. methane emissions. Livestock is responsible for 26 percent, the agency estimates. Yet while that’s the official number, a paper last year in the Journal of Geophysical Research: Atmospheres raised the possibility that the EPA’s measurements are off, and that the biggest source of methane from human activity may in fact be ruminants — more than 90 percent of them cows raised for beef and dairy production. While methane emissions from the energy sector declined between 1990 and 2013, the contribution from agriculture rose by 11 percent, according to the EPA. (Though in later years cattle populations fell and so did livestock-related methane.) The World Bank estimates that overall global methane emissions rose 17 percent between 1990 and 2010. In 2014, the U.S. government announced a goal to reduce methane output from dairy cattle by 25 percent by 2020. That’s why scientists worldwide are looking for ways to produce a less noxious cow. Experiments target the animal inside and out, testing variations in feed, antimethane additives and experimental vaccines. The Canadian project goes deeper, using genetics to develop and breed animals that are naturally less burpy. All approaches are promising, but no single one has hit the sweet spot: reducing methane dramatically while not harming the cow or dampening production of farms and ranches. Any solution can’t be too impractical or too expensive, either. The good news is that this is one issue where the interests of the $44 billion beef industry and environmentalists may converge — cattle that pollute less might live longer or get by with less feed, improving the profit margins of farms and ranches. “We’ve been selling the greenhouse gas story as a win-win to farmers,” says Conrad Ferris, head of dairy research at the Agri-Food and Biosciences Institute in Hillsborough, Northern Ireland. Most methane-reducing experiments don’t concern the cow per se; they go after the microscopic ecosystem huddled inside the animal’s gut. When a cow eats, hay, grass and other plant material land inside the rumen, the largest of the four compartments of the bovine stomach, which can hold 150 to 190 liters of food and water. Ruminant digestion is a microbial marvel: A portion of the stomach is sectioned off into a sophisticated vat for fermentation, which occurs when microorganisms slice sugar and other large molecules into smaller ones. (Without fermentation, grapes and agave couldn’t become wine and tequila.) Trapped inside the rumen, bacteria digest the components of the forage, especially cellulose, the large chains of glucose that form the main structural support of the cell walls of plants. Cellulose is the reason green plants tend to be stiff and rigid. People aren’t born with the enzymes to cope with cellulose, which is why we don’t eat grass. When humans eat foods such as fruits and vegetables, the cellulose acts as dietary fiber. Because it resists digestion, cellulose doesn’t provide energy. It does help a person feel full with fewer calories and maintain the health of the intestine, and of the microbiome inside. Thanks to a multichambered stomach and helpful microbes, cattle can digest food that humans cannot. The largest chamber, the rumen, is a fermentation vat that breaks down cellulose. Microbes soak up the resulting hydrogen, producing methane (CH ), which the cow releases, mainly in burps. But a ruminant animal’s microorganisms can extract the energy locked up in cellulose. Its digestive system includes microbes called methanogens, ancient entities distinct from bacteria and other microorganisms. Methanogens can live in other oxygen-starved environments, such as the bottom of lakes. When microbes in the rumen digest cellulose, they leave behind nutrients that the cow needs plus methane gas, created when methanogens soak up the hydrogen left over from fermentation. The relationship is straightforward: The more the cow eats, the more it ferments, the more methane produced. Emissions from a grown dairy cow can amount to about 260 to 650 grams of methane per day. Consider that the nation has 98 million head of cattle and you see the scope of the problem. One mid-sized animal could put out about 150 kilograms of methane every year, which has the same environmental impact as driving from New York to Los Angeles — three times. Scientists are trying to interfere with the chemical steps that lead to methane production in ways that don’t harm the overall health or productivity of the cows. Over the last few years, researchers have tried adding natural and laboratory-made substances to cow feed. One of them is nitrate. The idea is that, given the extra nitrogen, methanogens sopping up excess hydrogen will form ammonia (composed of one nitrogen and three hydrogen atoms) instead of methane (one carbon and four hydrogens). Last year, scientists from the Lethbridge Research Centre in Canada, writing in the Canadian Journal of Animal Science, reviewed nitrate-adding experiments dating back to the 1960s. Some laboratory tests yielded dramatic results, reducing cow methane emissions by as much as 70 percent. In other studies, the nitrate didn’t affect the growth or appetite of the cows, or milk or meat production. Problem is, in the rumen, nitrate is broken down into nitrite, which can interfere with the action of red blood cells. One cow died in an experiment and six others had to be rescued. “One of the challenges is, how do you deliver it in a way that prevents nitrate toxicity in the animal,” says Wendy Powers, director of environmental stewardship for animal agriculture at Michigan State University in East Lansing. Other scientists have experimented with plants that can influence microbes and change the methane-producing chemistry of the rumen, with the hope that “the public will more readily accept something that is natural,” says Alexander Hristov, a professor of dairy nutrition at Penn State University. He and his colleagues added a by-product of cashew nut processing to feed and reduced methane emissions by a modest 8 percent, they reported in June in the Journal of Dairy Science. He has also experimented with adding oregano to feed, which reduced methane. But it got to be too much. “We were feeding 500 grams of oregano per cow per day,” he says. “That is not going to be economical.” Different approaches are under study to reduce bovine methane emissions. Most try to change the chemistry or microbial makeup of the rumen. Promotes formation of ammonia instead of methane Alters the chemistry of the rumen Substitutes feed that relies less on fermentation Increases milk production in dairy cows; already available Can be expensive; environmental cost if transportation needed Blocks enzyme that drives last step of methane formation In one experiment, methane dropped 30 percent and cows gained weight Cows require less feed for same growth Changes are slow; may affect other traits, such as health or fertility Sources: C. Lee and K.A. Beauchemin/Can. J. Anim. Sci. 2014; G. Wischer et al/Animal 2013; H.P. Jiao et al/J. Dairy Sci. 2014; A.N. Hristov et al/Proc. Natl. Acad. Sci. 2015; M. Aspin; J.A. Basarab et al/Animal 2013 Powers mentored a Michigan State grad student who tried adding an extract from tea to feed, which raised yet another complication: “You had to get so much in there to be effective, palatability became an issue,” she says. Cows will shun a solution that tastes bad. Overall, she says, experiments with various plant extracts have been inconsistent. Hristov’s team devised another approach that appears to pass the taste test. Researchers experimented with a synthetic feed additive designed to interfere with an enzyme that drives the last step of methane formation. In the Aug. 25 Proceedings of the National Academy of Sciences, the researchers reported that 48 cows given the additive for 12 weeks produced 30 percent less methane than cows that ate only their normal feed. The additive did not affect the animals’ appetite or milk production. “This is the most promising feed additive we have worked with,” Hristov says. “In my opinion, this is the answer to the gut problem.” The Irish scientists are also trying to reduce methane by decreasing the proportion of roughage (the grass and hay that leads to methane production) and increasing the amount of concentrates, which are plants that are easier to digest without fermentation, such as corn and soybeans. Last year, in the Journal of Dairy Science, the researchers described one such experiment in 40 grazing cows. As concentrates increased, so did milk production. The cows’ overall methane emissions weren’t affected, but with higher production, the amount of methane that accompanied each liter of milk was reduced, which eases the environmental impact. That experiment was on animals in the field. Experiments in barns have also demonstrated that more concentrates mean less methane per liter of milk produced, Ferris says. But concentrates are costly. “There comes a point when even the higher milk production doesn’t cover the cost of concentrates,” he says. Also, if the overall goal is to ease the impact on the environment, the production and shipping of concentrates has its own carbon footprint. A concern with food additives is that the methanogens in the rumen might adapt to their new diet after a time and resume methane production at the same level. For that reason, an additive would probably need to be repeatedly fed and monitored through the animal’s life span, potentially adding to cost and labor, says Mark Aspin, manager of the Pastoral Greenhouse Gas Research Consortium in Wellington, New Zealand, which partners with the government research agency AgResearch. Researchers in New Zealand — a country with more cows than people — are developing an antimethane vaccine that could reduce the population of methanogens in the rumen without affecting an animal’s weight, milk production or breeding. The advantage of a vaccine, Aspin says, is that it could theoretically be administered just once, or at least only annually. Also, farmers and ranchers are used to vaccinations; adding one more shot wouldn’t be much of a burden on existing agricultural practices. It could be used across other economically important ruminants, such as sheep (which outnumber his country’s human population 7-to-1), he says. The technology is still far from the farm, however. The New Zealand research team has identified antibodies to the gut microbes and is in the process of amplifying the important pieces of those antibodies and incorporating them into a vaccine. In the journal Animal in 2013, the New Zealand team reported finding genetic sequences in methanogens that are attractive targets for a vaccine. They’ve also developed a vaccine injection that produces methanogen antibodies in saliva, which would then travel into the rumen. This is one key to delivery, since an average cow produces 100 to 150 liters of spit a day to aid in digestion. Further experiments would have to demonstrate that lowering methanogens won’t affect the animal’s overall health. “The concern is that removing methanogens from the rumen may allow hydrogen to accumulate,” Aspin says. However, “in the limited studies that have been done to date, it doesn’t appear that this is the case.” Sidestepping digestion altogether, some researchers are focusing on breeding a cleaner cow. In Ireland, Ferris and his colleagues experiment with livestock management. Part of the idea is to lengthen the life span of any given animal. “It takes over two years from when a calf is born until she produces her first liter of milk,” he says. If a cow lives longer, her lifetime methane production is spread out over more liters of milk. Also, a farmer does not have to replace as many members of the herd with young, all-methane, no-milk youngsters. In a paper published last year in the Journal of Dairy Science, his research team reported that Norwegian breeds had greater longevity than Holsteins, which make up more than 80 percent of U.S. dairy cows. At the Lacombe Research Centre in the Canadian province of Alberta, researchers collect cow burps when the animals eat from a specially designed fume hood made by C-Lock, Inc. The scientists are breeding animals that naturally produce lower amounts of methane (CH ). Researchers in Alberta are developing lines of cattle that produce less methane because they are born that way. “If you use a feed additive, you’ve got to add it all the time,” says John Basarab, a research scientist for beef cattle production and genetics at Alberta Agriculture and Forestry. But a naturally more efficient cow can get by on less feed for the same growth. Over the last two decades, Basarab and his research team have measured about 5,000 cattle for feed efficiency, and report that old-fashioned selective breeding can produce animals that release up to 25 percent less methane. “In every breed there are animals that are efficient, or inefficient,” he says. The researchers began the research not with methane in mind, but with the idea that animals that extract the most calories from their feed will ultimately be more economical. “Essentially there are animals that eat less for the same amount of growth,” Basarab says. Approaching the methane issue through genetics is slow (the gestation period for a cow is about 280 days), he concedes, but it also has the advantage of being “cumulative and permanent.” He and others say the day may come for cows — just as it did for cars — when governments require certain limits on emissions. And just as organic foods have risen in popularity, consumers may start demanding low-methane products. More and more consumers want to know where their food comes from and whether it’s being produced in a sustainable way, Basarab says. “If you don’t take care of these things, the public might just say that’s a bad way of producing food and we’re not going to buy it.” Making the most of manure The average dairy cow generates about 45 kilograms of manure daily. Next to the animal’s burps, its droppings are a substantial source of methane : Manure accounts for 10 percent of U.S. methane emissions. (For all their gassiness, farts release just a tiny fraction of a cow’s methane.) Much of the focus of the U.S. government’s methane-tackling “Biogas Opportunities Roadmap” was on cow patties. Unlike burps that waft into the air, the methane from manure can be captured by devices called digesters. The airtight devices use the methane generated by the methanogens in manure, which thrive in oxygen-poor environments, to produce energy. The output — either fuel or electricity — powers farm operations or is sold. Digesters are popular at landfills — including one that collects waste at Disney World in Florida — but they are rare in agriculture. Just 239 manure digesters are in operation on U.S. farms (of which there are just over 2 million), according to the Environmental Protection Agency. Yet they generate enough electricity to power the equivalent of about 70,000 homes. — Laura Beil This story appears in the November 28, 2015, Science News with the headline, "Greener cows: Research rounds up less burpy bovines." Editor's note: On November 20, 2015, a clarification was added to the caption for the illustration "As fumes flow" and the credit was corrected.
Seito L.N.,Biosciences Institute |
Sforcin J.M.,São Paulo State University |
Bastos J.K.,University of Sao Paulo |
Di Stasi L.C.,Biosciences Institute
Journal of Pharmacy and Pharmacology | Year: 2015
Objectives Zeyheria montana is a medicinal plant used in Brazilian folk medicine for treating skin affections, ulcers, inflammation and diarrhoea, and as an antisyphilitic and antiblenorrhagic agent, but little is known about its mechanisms of action. Herein, a bio-guided assay was carried out to further evaluate its antioxidant and immunomodulatory effects, and the possible benefits on experimental intestinal inflammation. Methods Extracts, partitions, fractions and isolated compounds were tested for inhibition of lipid peroxidation. Isolated compounds were tested in vitro for its antioxidant and immunomodulatory action prior to in-vivo evaluation in trinitrobenzenesulfonic acid-induced rat colitis. Key findings Two major compounds were identified in the leaf dichloromethane extract: 3′-hydroxy-5,7,4′-trimethoxyflavone and 6-hydroxy-5,7-dimethoxyflavone, which exhibited an antioxidant activity. The compounds protected the colonic glutathione levels in more than 90% despite the absence of protection against the gross macroscopic colonic damage. In addition, the compounds inhibited IL-1ß secretion by macrophages in 91.5% and 72.7% respectively, whereas both reduced IL-6 secretion in about 44.5%. Conclusions The major active compounds from Z. montana leaves exerted antioxidant and immunomodulatory effects, endorsing the use of Z. montana in folk medicine as an anti-inflammatory agent. However, further investigation is still needed regarding medicinal plants and the identification of candidate compounds for the treatment of the inflammatory bowel diseases. © 2014 Royal Pharmaceutical Society.
News Article | February 15, 2017
The geneticist David Vendrami from Bielefeld University is studying ways in which populations of scallops differ. Credit: Bielefeld University The scallop is one of the largest edible molluscs, and gourmets consider it to be a great delicacy. To meet this demand, the fishing industry cultivates these shellfish in coastal aquafarms. In a new analysis, behavioural ecologists at Bielefeld University have confirmed that cultivated scallops developed their own genetic structure that differs from that of natural scallops. The biologists studied a total of nine populations of scallops (Pecten maximus) along the coast of Northern Ireland. They are presenting their results this Wednesday in the research journal 'Royal Society Open Science'. 'Of the nine scallop populations studied, only one shows a marked genetic difference from the others and that is the artificially cultivated type,' reports Joseph I. Hoffman, head of the Molecular Behavioural Ecology research group. New breeds are cultivated in, for example, mesh cages in coastal waters. Now and then, young scallops escape through the mesh and are thereby able to impact on natural populations. Biologists use the term population to describe a group of organisms of one species that live together in one area and are linked together genetically through reproduction over successive generations. The researchers analysed the genetic architecture of the mollusc populations. 'Studying the genetic architecture of animal populations helps us to understand which external appearance an organism can adopt - for example, how large a mollusc can become or whether it can develop red streaks on its surface,' says David Vendrami. The doctoral student has analysed a total of 180 mollusc samples. The Agri-Food and Biosciences Institute in Belfast (Northern Ireland) collected these in February 2015 during an excursion along the Northern Irish Atlantic coast. The researchers have not just confirmed how breeding affects scallop populations. Their study also confirms that these molluscs adapt their shape and internal colouring very flexibly to conditions in their environment, and that they do this independently of whether they belong to the one cultivated or the eight natural populations. 'We have tested how far genes relate to appearance. However, that is very probably not the case. It is highly likely that the external characteristics of the molluscs depend on their surroundings,' says Vendrami. Scientists at Bielefeld also used this study to compare a classical DNA analysis with a new procedure. The classical analysis proceeds by evaluating repeated short DNA sequences (microsatellites) in order to compare samples from different organisms. The modern procedure (RAD sequencing) takes less time to analyse thousands of times more DNA sequences. 'The new procedure is markedly better at finding differences in the populations than the classical approach,' says David Vendrami. In their future research, Hoffman, Vendrami, and their colleagues will be going beyond Northern Ireland and studying samples along the entire Atlantic coast from Norway to Portugal as well as in the Mediterranean. Their aim is to find out how scallops as well as other crustaceans react to different environmental conditions in terms of their growth. Explore further: New study on how shellfish create their shells More information: David L. J. Vendrami et al, RAD sequencing resolves fine-scale population structure in a benthic invertebrate: implications for understanding phenotypic plasticity, Royal Society Open Science (2017). DOI: 10.1098/rsos.160548
E Silva F.M.P.,Laboratory of Parasitic Diseases |
E Silva F.M.P.,Biosciences Institute |
Monobe M.M.,Laboratory of Parasitic Diseases |
Monobe M.M.,Biosciences Institute |
And 2 more authors.
Parasitology Research | Year: 2012
The intestinal protozoan parasite Giardia duodenalis (syn. Giardia intestinalis and Giardia lamblia) is a widespread enteric pathogen in human and domestic animals. This organism is one of the most common parasites in domestic dogs in Brazil. In this study, we determined the occurrence and genetic characterization of G. duodenalis isolated from dogs from south-central São Paulo state, Brazil. A total of 300 fecal samples were collected. Fecal specimens were screened for the presence of G. duodenalis using microscopy (zinc sulfate solution flotation technique) and polymerase chain reaction (PCR) targeting the small subunit ribosomal (SSU-rDNA) and glutamate dehydrogenase (GDH) genes. Genetic characterization was performed using restriction fragment length polymorphisms (RFLP) and sequencing analysis of the GDH gene. In addition, selected samples were further characterized by RFLP and sequencing of the β-giardin gene. The overall occurrence of G. duodenalis was 17.3% (52/300). The occurrence was higher in stray dogs (28%) than in household dogs (6.25%). Of the 36 PCR-positive samples that were selected for genotyping, only dog-specific genotype C (20 isolates), D (11 isolates) and mixed C+D (five isolates) isolates were detected in the study. This study provides current information on the infection rates of G. duodenalis genotypes in canine populations and describes for the first time the presence of mixed infections within host-specific C and D genotypes in dogs in Brazil. These genotypes were widespread and commonly found in domestic dogs living in urban and suburban environments of the studied area and confirmed the endemic status of Giardia in this region. © Springer-Verlag 2011.
Lindsay A.J.,Biosciences Institute |
Lindsay A.J.,University Pierre and Marie Curie |
Jollivet F.,University Pierre and Marie Curie |
Horgan C.P.,Biosciences Institute |
And 5 more authors.
Molecular Biology of the Cell | Year: 2013
Myosin Va is a widely expressed actin-based motor protein that binds members of the Rab GTPase family (3A, 8A, 10, 11A, 27A) and is implicated in many intracellular trafficking processes. To our knowledge, myosin Va has not been tested in a systematic screen for interactions with the entire Rab GTPase family. To that end, we report a yeast two-hybrid screen of all human Rabs for myosin Va-binding ability and reveal 10 novel interactions (3B, 3C, 3D, 6A, 6A′, 6B, 11B, 14, 25, 39B), which include interactions with three new Rab subfamilies (Rab6, Rab14, Rab39B). Of interest, myosin Va interacts with only a subset of the Rabs associated with the endocytic recycling and post-Golgi secretory systems. We demonstrate that myosin Va has three distinct Rab-binding domains on disparate regions of the motor (central stalk, an alternatively spliced exon, and the globular tail). Although the total pool of myosin Va is shared by several Rabs, Rab10 and Rab11 appear to be the major determinants of its recruitment to intracellular membranes. We also present evidence that myosin Va is necessary for maintaining a peripheral distribution of Rab11- and Rab14-positive endosomes. © 2013 Lindsay et al.
Horgan C.P.,Biosciences Institute |
Hanscom S.R.,Biosciences Institute |
Jolly R.S.,University College London |
Futter C.E.,University College London |
McCaffrey M.W.,Biosciences Institute
Biochemical and Biophysical Research Communications | Year: 2010
The mechanochemical forces that move and position intracellular organelles and their intermediates in eukaryotic cells are provided by molecular motor proteins which include the cytoplasmic dynein-1 motor complex. Recently, we identified the Rab11 GTPase effector protein Rab11-FIP3 (henceforth, FIP3) as a novel binding-partner for dynein light intermediate chain 1 (DLIC-1, gene symbol DYNC1LI1), a subunit of cytoplasmic dynein-1. Here, we show that FIP3 also binds the dynein light intermediate chain 2 subunit (DLIC-2, gene symbol DYNC1LI2). We show that like DLIC-1, DLIC-2 binds the amino-terminal 435 amino acids of FIP3 and that FIP3 links Rab11a to DLIC-2. We also show that FIP3 recruits DLIC-2 onto membranes and that DLIC-2 is necessary for the accumulation of endocytosed-transferrin (Tfn) at the pericentrosomal endosomal-recycling compartment (ERC). Finally, we demonstrate that overexpression of FIP3 fragments the Golgi complex by sequestering cytoplasmic dynein-1. In conclusion, we have identified FIP3 as the first membrane-associated interacting-partner for DLIC-2 and propose that this interaction serves to control endosomal trafficking from sorting endosomes to the ERC. © 2010 Elsevier Inc.
Ryan R.P.,BioSciences Institute |
Dow J.M.,BioSciences Institute
Virulence | Year: 2010
In the plant pathogen Xanthomonascampestris pv. campestris (Xcc) a two component system comprising RpfG and the complex sensor kinase RpfC is implicated in sensing and responding to the cell-cell signaling molecule DSF to positively regulate the synthesis of virulence factors such as extracellularenzymes, bio film structure and motility. RpfG is a two-component regulator witha CheY-like receiver domain attached to an HD-GYP cyclic di-GMP phosphodiesterasedomain. In a recent paper weshowed that that the physical interaction of RpfG with two proteins with a diguanylatecyclase (GGDEF) domain, acts tocontrol a sub-set of RpfG-regulated virulence functions. These protein-proteininteractions required the conserved GYPmot if in the HD-GYP domain of RpfGand were dependent on DSF signaling. Here we discuss these findings, considering in particular different scenarios for the role of RpfG in multiple signaling pathways involving cyclic di-GMP that impinge on virulence. © 2010 Landes Bioscience.