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October 4, 2011, 10:15 PM CT

Dragonflies: The Flying Aces of the Insect World

Dragonflies: The Flying Aces of the Insect World
Next time you see a dragonfly, try to watch it catch its next meal on the go. Good luck!

"Unless we film it in high speed, we can't see whether it caught the prey, but when it gets back to its perch, if we see it chewing, we know that it was successful," says Stacey Combes, a biomechanist at Harvard University. With support from the National Science Foundation (NSF), she and her team are studying how dragonflies pull off complicated aerial feats that include hunting and mating in mid-air. She set up her lab in typical "dragonfly country".

"Our lab is at the Concord Field Station in Bedford, Mass. This is a field station of Harvard University about a half-hour from the main campus," says Combes. "We're surrounded by woods and ponds, which is an ideal habitat to find dragonflies".

The scientists have already identified 20 species at the pond so far. On this outing, they hope to net a few to study. But, it's not easy to catch a dragonfly.

"Alright, I got one. I lost it," exclaims team member and biomechanist Jay Iwasaki. "It's a Libellula cyanea," he notes when he finally catches one. "It's in the family of Libellulidae, which are dragonflies known as skimmers; this is a male. You can tell this species in particular from the white dots on its wings".........

Posted by: Kelly      Read more         Source


August 4, 2011, 8:22 AM CT

Effects of Rising Carbon Dioxide on Rangelands

Effects of Rising Carbon Dioxide on Rangelands
ARS plant physiologist Jack Morgan is leader of a group replicating anticipated higher carbon dioxide and temperature levels to study their impact on semi-arid rangeland grasses.
Rising carbon dioxide (CO2) levels can reverse the drying effects of predicted higher temperatures on semi-arid rangelands, as per a research studypublished recently in the scientific journal Nature by a team of U.S. Department of Agriculture (USDA) and university scientists.

Warmer temperatures increase water loss to the atmosphere, leading to drier soils. In contrast, higher CO2 levels cause leaf stomatal pores to partly close, lessening the amount of water vapor that escapes and the amount of water plants draw from soil. This newly released study finds that CO2 does more to counterbalance warming-induced water loss than previously expected. In fact, simulations of levels of warming and CO2 predicted for later this century demonstrated no net change in soil water, and actually increased levels of plant growth for warm-season grasses.

"By combining higher temperatures with elevated CO2 levels in an experiment on actual rangeland, these scientists are in the process of developing the scientific knowledge base to help prepare managers of the world's rangelands for what is likely to happen as climate changes in the future," said Edward B. Knipling, administrator of the Agricultural Research Service (ARS), USDA's principal intramural scientific research agency.........

Posted by: Erica      Read more         Source


July 21, 2011, 10:04 PM CT

An eye gene colors butterfly wings red

An eye gene colors butterfly wings red
A single gene controls the repeated evolution of red color patten mimicry in passion-vine butterflies.

Credit: STRI
Red may mean STOP or I LOVE YOU! A red splash on a toxic butterfly's wing screams DON'T EAT ME! In nature, one toxic butterfly species may mimic the wing pattern of another toxic species in the area. By using the same signal, they send a stronger message: DON'T EAT US! .

Now several research teams that include Smithsonian researchers in Panama, have discovered that Heliconius butterflies mimic each other's red wing patterns through changes in the same gene.

Not only does this gene lead to the same red wing patterns in neighboring species, it also leads to a large variety of red wing patterns in Heliconius species across the Americas that result when it is turned on in other areas of the wings.

Because different butterfly species evolved red wing patterns independently, resulting in a huge variety of patterns we see today, scientists thought that different genes were responsible in each case.

"The variety of wing patterns in Heliconius butterflies has always fascinated collectors," said Owen McMillan, geneticist at the Smithsonian Tropical Research Institute, "People have been trying to sort out the genetics of mimicry rings since the 1970's. Now we put together some old genetics techniques and some newer genomics techniques and came up with the very surprising result that only one gene codes for all of the red wing patterns. The differences that we see in the patterns seems to be due to the way the gene is regulated".........

Posted by: Kelly      Read more         Source


July 20, 2011, 10:05 PM CT

Salt marsh sparrows beat the heat

Salt marsh sparrows beat the heat
The song sparrow is one of the several sparrow species that showed a difference in bill size depending on the daily high summer temperatures of their salt marsh breeding habitats.

Credit: Cephas

Birds use their bills largely to forage and eat, and these behaviors strongly influence the shape and size of a bird's bill. But the bill can play an important role in regulating the bird's body temperature by acting as a radiator for excess heat. A team of researchers have observed that because of this, high summer temperatures have been a strong influence in determining bill size in some birds, especially species of sparrows that favor salt marshes. The team's findings are published in the scientific journal Ecography, July 20.

Researchers at the Smithsonian Migratory Bird Center at the Smithsonian's Conservation Biology Institute and his colleagues examined five species of sparrow that inhabit salt marshes on the East, West and Gulf coasts of North America. While these marshes are very similar in makeup and structure, the main difference among them is summer temperatures. Focusing on 10 species and subspecies of tidal salt marsh sparrow, the team measured 1,380 specimens and observed that the variation in the sparrows' bill size was strongly correlation to the variation in the daily high summer temperatures of their salt marsh breeding habitats�the higher the average summer temperature, the larger the bill. Birds pump blood into tissue inside the bill at high temperatures and the body's heat is released into the air. Because larger bills have a greater surface area than smaller bills, they serve as more effective thermoregulatory organs under hot conditions. On average, the study found the bills of sparrows in marshes with high summer temperatures to be up to 90 percent larger than those of the same species in cooler marshes.........

Posted by: Kelly      Read more         Source


July 5, 2011, 9:00 PM CT

Termites' digestive system could act as biofuel refinery

Termites' digestive system could act as biofuel refinery
Mike Scharf's work with termites has shown that the insects' digestive systems may help break down woody biomass for biofuel production.

Credit: Purdue Agricultural Communication photo/Tom Campbell

Usage Restrictions: None

One of the peskiest household pests, while disastrous to homes, could prove to be a boon for cars, as per a Purdue University study.

Mike Scharf, the O. Wayne Rollins/Orkin Chair in Molecular Physiology and Urban Entomology, said his laboratory has discovered a cocktail of enzymes from the guts of termites that appears to be better at getting around the barriers that inhibit fuel production from woody biomass. The Scharf Laboratory observed that enzymes in termite guts are instrumental in the insects' ability to break down the wood they eat.

The findings, reported in the early online version of the journal PLoS One, are the first to measure the sugar output from enzymes created by the termites themselves and the output from symbionts, small protozoa that live in termite guts and aid in digestion of woody material.

"For the most part, people have overlooked the host termite as a source of enzymes that could be used in the production of biofuels. For a long time it was thought that the symbionts were solely responsible for digestion," Scharf said. "Certainly the symbionts do a lot, but what we've shown is that the host produces enzymes that work in synergy with the enzymes produced by those symbionts. When you combine the functions of the host enzymes with the symbionts, it's like one plus one equals four".........

Posted by: Kelly      Read more         Source


July 5, 2011, 8:56 PM CT

Cool-season grasses more profitable than warm-season grasses

Cool-season grasses more profitable than warm-season grasses
Access to swine effluent or waste water can help a producer grow more grass. But a Texas AgriLife Researcher says the grass is "greener" economically if it is a cool-season rather than a warm-season variety.

Dr. Seong Park, AgriLife Research economist in Vernon, said while the warm-season grasses appear to have a greater growth boost with swine effluent application, the cool-season grasses have marketing advantages that make it a more viable economic option for producers in the Oklahoma Panhandle and Southern Plains.

Park recently had the results of his study reported in the Journal of American Society of Farm Manager and Rural Appraisal. The study was funded by a U.S. Department of Agriculture grant for "Comprehensive Animal Waste Systems in Semiarid Ecosystems." Cooperators in the study were Dr. Jeffrey Vitale and Dr. Jeffory Hattey, both with Oklahoma State University.

The study reviewed the risk and economics of intensive forage production systems under four alternative types of forage and two alternative nitrogen sources, he said. The results will help farmers make better informed production decisions.

The study compared two cool-season grasses � orchard grass and wheatgrass � with two warm-season grasses � Bermuda grass and buffalo grass, he said. The two nitrogen sources used to fertilize the crop were urea or swine effluent.........

Posted by: Erica      Read more         Source


July 5, 2011, 8:15 PM CT

Arrival of Whooping Crane

Arrival of Whooping Crane
After an 88-year-long hiatus North America's tallest bird, the statuesque whooping crane (Grus americana), is once again on exhibit at the Bird House at the Smithsonian's National Zoological Park. An 11-year-old male whooping crane named Rocky left Homosassa Springs State Park in Florida and is now on exhibit in the nation's capital. Whooping cranes are one of only two crane species native to the United States. There are only eight other zoos in the U.S. which exhibit these birds.

"It is an honor for the National Zoo to once again exhibit this magnificent species," said Dennis Kelly, director of the Smithsonian's National Zoological Park. "Eventhough most people have heard of whooping cranes, very few have had the privilege of seeing one in person. We are thrilled to have Rocky here as an ambassador for his species".

Rocky is only the fourth whooping crane to call the National Zoo home. The Zoo's first crane, a wild-caught bird of unknown sex, arrived in 1897. Its last, a female, died in 1923.

By 1938, hunting and agricultural expansion had decimated wild whooping crane populations to an estimated 21 individuals. Zoos, research centers and nature preserves acted quickly to curtail the threat of extinction. Working together, they carefully matched individual birds that did not have mates in order to stabilize populations and achieve the greatest genetic diversity possible-a considerable challenge, given the population bottleneck.........

Posted by: Kelly      Read more         Source


June 21, 2011, 11:39 PM CT

New not-so-sweet potato resists pests and disease

New not-so-sweet potato resists pests and disease
Scientists from Clemson University and the USDA Agricultural Research Service have developed a new variety of not-so-sweet potato, called Liberty.
image by: Clemson University
Researchers from Clemson University and the USDA Agricultural Research Service have developed a new variety of not-so-sweet potato, called Liberty.

Known as a boniato, or tropical sweet potato, Liberty has a dark red skin and light yellow, dry flesh with a bland flavor. Boniato potatoes originated in the tropical Americas and are grown in south Florida in the United States. They can be served fried, mashed or in soup.

"We developed Liberty because other boniato varieties are susceptible to damage by nematodes (microscopic parasitic worms)," said John Mueller, plant pathologist and director of Clemson's Edisto Research and Education Center in Blackville.

Mueller worked with a team of researchers from the U.S. Vegetable Laboratory in Charleston led by entomologist Mike Jackson. Other USDA Agricultural Research Service team members included agronomist Howard Harrison, plant pathologist Judy Thies and plant geneticist Janice Bohac.

The Liberty potato is highly resistant to nematodes and moderately resistant to insect pests and fusarium wilt, a fungal disease. Liberty potatoes have good baking quality, store well and do not darken after peeling as most boniato potatoes do. Home gardeners, as well as commercial producers and organic growers, can grow the Liberty potato.........

Posted by: Erica      Read more         Source


June 21, 2011, 11:30 PM CT

Where will grizzly bears roam?

Where will grizzly bears roam?
Three grizzly bears walk within the Crown of the Continent.

Credit: WCS

The independent evaluation, written by WCS Senior Conservation Scientist Dr. John Weaver, is a compilation and synthesis of the latest information on these species � and how climate change may affect them � from 30 biologists in the region and from nearly 300 scientific papers. In addition, Weaver spent four months hiking and riding horseback through these remote roadless areas to evaluate their importance for conservation.

The Crown of the Continent is a trans-border ecosystem of dramatic landscapes, pristine water sources, and diverse wildlife that stretches more than 250 miles along the Rocky Mountains from Glacier National Park-Bob Marshall Wilderness in Montana north to the Canadian Rockies. Weaver focused his evaluation on public lands in the Montana portion �one of the most spectacular and intact ecosystems remaining in the lower 48 states. Since 1910 when Glacier National Park was established, citizens and government representatives have worked hard to protect the core wildlands and wildlife in this region.

"These visionary leaders left a great gift and remarkable legacy," said Dr. Weaver, "But new data and emerging threats like climate change indicate it may not have been enough. There is a rare opportunity now to complete the legacy of conservation for present and future generations".........

Posted by: Kelly      Read more         Source


June 13, 2011, 7:48 AM CT

Life-history traits may affect DNA mutation rates

Life-history traits may affect DNA mutation rates
A composite image of 4 of the 32 mammal species whose life-history traits and DNA mutation rates are studied in the Penn State University laboratory of Kateryna Makova. From the top left corner, moving clockwise: a wild dog, a hyrax, a bat, and an elephant. Individual images are online at http://www.science.psu.edu/news-and-events/2011-news/Makova6-2011.

Credit: Anton Nekrutenko, Makova lab, Penn State University

For the first time, researchers have used large-scale DNA sequencing data to investigate a long-standing evolutionary assumption: DNA mutation rates are influenced by a set of species-specific life-history traits. These traits include metabolic rate and the interval of time between an individual's birth and the birth of its offspring, known as generation time. The team of scientists led by Kateryna Makova, a Penn State University associate professor of biology, and first author Melissa Wilson Sayres, a graduate student, used whole-genome sequence data to test life-history hypotheses for 32 mammalian species, including humans. For each species, they studied the mutation rate, estimated by the rate of substitutions in neutrally evolving DNA segments -- chunks of genetic material that are not subject to natural selection. They then correlated their estimations with several indicators of life history. The results of the research would be reported in the journal Evolution on 13 June 2011.

One of the a number of implications of this research is that life-history traits of extinct species now could be discoverable. "Correlations between life-history traits and mutation rates for existing species make it possible to develop a hypothesis in reverse for an ancient species for which we have genomic data, but no living individuals to observe as test subjects," Makova explained. "So, if we have information about how extant species' life history affects mutation rates, it becomes possible to make inferences about the life history of a species that has been extinct for even tens of thousands of years, simply by looking at the genomic data".........

Posted by: Kelly      Read more         Source


May 29, 2011, 2:41 PM CT

Solving mouse genome dilemma

Solving mouse genome dilemma
Laboratory research has always been limited in terms of what conclusions researchers can safely extrapolate from animal experiments to the human population as a whole. A number of promising findings in mice have not held up under further experimentation, in part because laboratory animals, bred from a limited genetic foundation, don't provide a good representation of how genetic diversity manifests in the broader human population.

Now, thanks to an in-depth analysis by a team led by Fernando Pardo-Manuel de Villena, PhD, in the UNC Department of Genetics and Gary Churchill, PhD, at The Jackson Laboratory in Bar Harbor, Maine, scientists will be able to use an online resource dubbed the Mouse Phylogeny Viewer to select from among 162 strains of laboratory mice for which the entire genome has been characterized. Phylogeny refers to the connections among all groups of organisms as understood by ancestor/descendant relationships. Pardo-Manuel de Villena is also a member of UNC Lineberger Comprehensive Cancer Center and the Carolina Center for Genome Sciences.

The results of the analysis that make this tool possible were published online today in the journal Nature Genetics

"The viewer provides researchers with a visual tool where they can actually go and look at the genome of the mouse strains they are using or considering, compare the differences and similarities between strains and select the ones most likely to provide the basis for experimental results that can be more effectively extrapolated to the diverse human population," said Pardo-Manuel de Villena.........

Posted by: Kelly      Read more         Source


May 8, 2011, 9:36 PM CT

Zombie ants have fungus on the brain

Zombie ants have fungus on the brain
Tropical carpenter ants (Camponotus leonardi) live high up in the rainforest canopy. When infected by a parasitic fungus (Ophiocordyceps unilateralis) the behaviour of the ants is dramatically changed. They become erratic and zombie-like, and are manipulated by the fungus into dying at a spot that provides optimal conditions for fungal reproduction. New research, published in BioMed Central's open access journal BMC Ecology, looks at altered behaviour patterns in Zombie ants in Thailand and shows how the fungus manipulates ant behaviour.

A multinational team of scientists investigated O. unilateralis infected carpenter ants in Thailand's rainforest. The growing fungus fills the ant's body and head causing muscles to atrophy and forcing muscle fibres apart. The fungus also affects the ant's central nervous system and while normal worker ants rarely left the trail, zombie ants walked in a random manner, unable to find their way home. The ants also suffered convulsions which caused them to fall to the ground. Once on the ground the ants were unable to find their way back to the canopy and remained at a lower, leafy, 'understory' which, at about 25cm above the soil was cooler and moister than the canopy, provided ideal conditions for the fungus to thrive.........

Posted by: Kelly      Read more         Source


April 5, 2011, 7:06 PM CT

Hotspots of genetic rearrangement

Hotspots of genetic rearrangement
In this image, hundredfold magnification of a single sperm precursor cell shows the chromosomes - in green - and the places where these chromosomes are most likely to break apart and re-form, called genetic recombination hotspots - in red. Genetic rearrangements at these hotspots have the potential to shuffle maternal and paternal chromosomes, the end results of which ensure that the genetic information in every sperm cell is unique. Source: Fatima Smagulova, Ph.D., USU, and Kevin Brick, Ph.D., NIDDK, NIH.
Scientists have zoomed in on mouse chromosomes to map hotspots of genetic recombination - sites where DNA breaks and reforms to shuffle genes. The findings of the researchers at the National Institutes of Health and Uniformed Services University of Health Sciences (USU) have the potential to improve the detection of genes associated with disease and to help understand the root causes of genetic abnormalities. The research, published online April 3 in Nature, moves researchers one step closer to understanding how mammals evolve and respond to their environments.

Genetic recombination occurs at hotspots in cells that form sperm and eggs. At these sites, rearrangements ensure that the combination of genes passed on to every sperm and egg cell is unique. By studying precursors of mouse sperm cells during the early stages of genetic recombination, the researchers have created a precise, first-of-its-kind map of recombination hotspots in a multi-celled organism.

With this map, scientists also hope to pinpoint where, how and why abnormalities in the number of chromosomes can occur. Such abnormalities - for instance, the extra copy of chromosome 21 that gives rise to Down syndrome - are the leading known cause of miscarriages, congenital birth defects, and mental retardation in the United States.........

Posted by: Janet      Read more         Source


April 1, 2011, 7:32 AM CT

Sun and shade leaves play different roles in tree canopies

Sun and shade leaves play different roles in tree canopies
'Outer' tree canopy leaves influence the sunlight reaching inner canopy leaves by changing their shape, says a newly released study.

The shape and physiology of leaves within the tree canopy is not constant, and can vary depending on their position within the tree crown. This phenomenon is expected to have important consequences for how trees cope with stress and use resources.

A newly released study describes how the leaves in the outer canopy of olive trees can influence the light environment within the canopy by changing their shape, as more elongated leaves resulted in higher levels of solar radiation inside the crown.

Author Rafael Rubio de Casas and his colleagues found that inner canopy leaves appear to be especially adapted to the use of diffuse solar radiation, which is more constant than direct radiation. They propose that outer canopy leaves change not only to maximize their own performance, but also to create a beneficial environment for the inner canopy leaves. They also suggest that leaves in various positions of the canopy can use different types of solar radiation for photosynthesis and operate at different time windows. Exposed leaves are expected to use direct solar radiation and be more active when the sun is close to the horizon, while shaded leaves specialize in the capture of diffuse radiation and are more active when the sun is higher.........

Posted by: Erica      Read more         Source


March 30, 2011, 10:53 PM CT

Killer whales in Antarctic waters prefer weddell seals

Killer whales in Antarctic waters prefer weddell seals
A Killer Whale circles an ice floe with a resting Weddell seal off the western Antarctic Peninsula. Researchers found the killer whales hunting in pack ice (pack ice killer whales) preferred Weddell seals to all other available prey.

Credit: Robert Pitman/NOAA

NOAA's Fisheries Service researchers studying the cooperative hunting behavior of killer whales in Antarctic waters observed the animals favoring one type of seal over all other available food sources, as per a research studyreported in the journal Marine Mammal Science.

Scientists Robert Pitman and John Durban from NOAA's Southwest Fisheries Science Center in La Jolla, Calif., observed killer whales hunting in ice floes, off the western Antarctic Peninsula during January of 2009. While documenting the whales' behavior of deliberately creating waves to wash seals off ice floes, the scientists noticed Weddell seals as their primary target, despite the availability of other prey species, especially the more abundant crabeater seals.

"These killer whales would identify and then attack Weddell seals almost exclusively, even though they made up only about 15 percent of the available seal population," said Pitman.

Killer whales creating waves to wash seals off ice floes in Antarctica had previously been observed only a handful of times. The whales, sometimes as a number of as seven abreast, charge the ice floe creating a wave that either washes the seal off the ice or breaks the ice into smaller pieces and more vulnerable to another attack. A prior study involving the authors suggested that this very distinctive killer whale population, which they refer to as "pack ice killer whales," is a separate species.........

Posted by: Kelly      Read more         Source


March 30, 2011, 10:48 PM CT

Declining rainfall is a major influence for migrating birds

Declining rainfall is a major influence for migrating birds
male American redstart.

Credit: Dan Pancamo

Instinct and the annual increase of daylight hours have long been believed to be the triggers for birds to begin their spring migration. Researchers at the Smithsonian Conservation Biology Institute, however, have observed that that may not be the case. Scientists have focused on how warming trends in temperate breeding areas disrupt the sensitive ecology of migratory birds. This new research shows that changes in rainfall on the tropical wintering grounds could be equally disruptive. The team's findings appear in scientific journal Proceedings of the Royal Society B, today, March 30.

A number of of the bird species that breed in the temperate forests, marshes and backyards of North America spend the winter months in the tropics of the Caribbean, and Central and South America. Insects are the primary food for a number of birds during the winter, and rainfall largely determines the amount of insects available. Climactic warming, however, is causing declining and more variable rainfall cycles in a number of areas, affecting the availability of insects and delaying when birds leave for their northern breeding grounds. To examine this, the Smithsonian researchers focused on American redstarts (Setophaga ruticilla), a member of the warbler family, at a non-breeding site in Jamaica where they conduct long-term studies.........

Posted by: Kelly      Read more         Source


March 30, 2011, 7:04 AM CT

Whale and dolphin death toll may have been greatly underestimated

Whale and dolphin death toll may have been greatly underestimated
The Deepwater Horizon oil spill of 2010 devastated the Gulf of Mexico ecologically and economically. However, a newly released study published in Conservation Letters reveals that the true impact of the disaster on wildlife appears to be gravely underestimated. The study argues that fatality figures based on the number of recovered animal carcasses will not give a true death toll, which appears to be 50 times higher than believed.

"The Deepwater oil spill was the largest in US history, however, the recorded impact on wildlife was relatively low, leading to suggestions that the environmental damage of the disaster was actually modest," said main author Dr Rob Williams from the University of British Columbia."This is because reports have implied that the number of carcasses recovered, 101, equals the number of animals killed by the spill".

The team focused their research on 14 species of cetacean, an order of mammals including whales and dolphins. While the number of recovered carcasses has been assumed to equal the number of deaths, the team argues that marine conditions and the fact that a number of deaths will have occurred far from shore mean recovered carcasses will only account for a small proportion of deaths.

To illustrate their point, the team multiplied recent species abundance estimates by the species mortality rate. An annual carcass recovery rate was then estimated by dividing the mean number of observed strandings each year by the estimate of annual mortality.........

Posted by: Kelly      Read more         Source


March 26, 2011, 10:29 PM CT

Primordial Soup Gets Spicier

Primordial Soup Gets Spicier
Scripps Oceanography Professor of Marine Chemistry Jeffrey Bada holds a preserved sample from a 1958 experiment done by "primordial soup" pioneer Stanley Miller. The residue in the sample contains amino acids created by the experiment. The samples had not undergone analysis until recently when Bada and colleagues discovered a wide range of amino acids using modern detection methods.
Stanley Miller gained fame with his 1953 experiment showing the synthesis of organic compounds believed to be important in setting the origin of life in motion. Five years later, he produced samples from a similar experiment, shelved them and, as far as friends and his colleagues know, never returned to them in his lifetime.

More 50 years later, Jeffrey Bada, Miller's former student and a current Scripps Institution of Oceanography, UC San Diego professor of marine chemistry, discovered the samples in Miller's laboratory material and made a discovery that represents a potential breakthrough in the search for the processes that created Earth's first life forms.

Former Scripps undergraduate student Eric Parker, Bada and his colleagues report on their reanalysis of the samples in the March 21 issue of Proceedings of the National Academy of Sciences. Miller's 1958 experiment in which the gas hydrogen sulfide was added to a mix of gases thought to bepresent in the atmosphere of early Earth resulted in the synthesis of sulfur amino acids as well as other amino acids. The analysis by Bada's lab using techniques not available to Miller suggests that a diversity of organic compounds existed on early planet Earth to an extent researchers had not previously realized.

"Much to our surprise the yield of amino acids is a lot richer than any experiment (Miller) had ever conducted," said Bada.........

Posted by: Janet      Read more         Source


March 26, 2011, 10:24 PM CT

Research brings habitat models into the future

Research brings habitat models into the future
MSU's wildlife habitat monitors track changes in Wolong Nature Reserve in southwestern China, home of the giant panda.
Models of wildlife habitat now can monitor changes over time more accurately and more easily, thanks to Michigan State University research.

"Monitoring and projecting future changes are essential for sustainable management of coupled human and natural systems, including wildlife habitat," said Jianguo "Jack" Liu, Rachel Carson Chair in Sustainability at MSU. "Innovative computer models are urgently needed for effective monitoring and projection".

Mao-Ning Tuanmu, doctoral student in MSU's Center for Systems Integration and Sustainability, and colleagues combine habitat modeling and remote sensing technology, then gain the ability to use one model to monitor various changes over time. Their work is published online in the Journal of Biogeography.

Tuanmu focused on panda habitat in Wolong Nature Reserve in southwestern China as part of an ongoing interdisciplinary effort to understand changes in the home of the giant panda. Models of habitat that portray information such as sources of food and forest cover are important tools. The trick has been to take these detailed models and expand them to help monitor changes over time.

"We built an integrated model at one point in time and then used that same model over different time periods," Tuanmu said. "We need more models like this one with good transferability to monitor short-term and project long-term changes in species distribution and habitat quality".........

Posted by: Kelly      Read more         Source


March 26, 2011, 10:16 PM CT

stranglers of the tropics

stranglers of the tropics
Credit: National Science Foundation

Kudzu, the plant scourge of the U.S. Southeast. The long tendrils of this woody vine, or liana, are on the move north with a warming climate.

But kudzu appears to be no match for the lianas of the tropics, researchers have found. Data from sites in eight studies show that lianas are overgrowing trees in every instance.

If the trend continues, these "stranglers-of-the-tropics" may suffocate equatorial forest ecosystems.

Tropical forests contain more than half of Earth's terrestrial species, and contribute more than a third of global terrestrial carbon and a third of terrestrial net primary productivity, says ecologist Stefan Schnitzer of the University of Wisconsin-Milwaukee.

Schnitzer is co-author with Frans Bongers of Wageningen University in the Netherlands of a paper on lianas in the current issue of the journal Ecology Letters.

"Any alteration of tropical forests has important ramifications for species diversity, productivity--and ultimately the global carbon cycle," says Schnitzer.

Tropical forests are indeed experiencing large-scale structural changes, the most obvious of which appears to be the increase in lianas, as per Robert Sanford, an NSF program director. The research was funded by the National Science Foundation (NSF)'s Division of Environmental Biology.........

Posted by: Erica      Read more         Source


March 25, 2011, 7:20 AM CT

Wild Birds May Play a Role in the Spread of Bird Flu

Wild Birds May Play a Role in the Spread of Bird Flu
Wild migratory birds may indeed play a role in the spread of bird flu, also known as highly pathogenic avian influenza H5N1.

A study by the U.S. Geological Survey, the United Nations Food and Agriculture Organization and the Chinese Academy of Sciences used satellites, outbreak data and genetics to uncover an unknown link in Tibet among wild birds, poultry and the movement of the often-deadly virus.

Scientists attached GPS satellite transmitters to 29 bar-headed geese - a wild species that migrates across most of Asia and that died in the thousands in the 2005 bird flu outbreak in Qinghai Lake, China. GPS data showed that wild geese tagged at Qinghai Lake spend their winters in a region outside of Lhasa, the capitol of Tibet, near farms where H5N1 outbreaks have occurred in domestic geese and chickens.

This is the first evidence of a mechanism for transmission between domestic farms and wild birds, said Diann Prosser, a USGS biologist at the USGS Patuxent Wildlife Research Center. "Our research suggests initial outbreaks in poultry in winter, followed by outbreaks in wild birds in spring and in the breeding season. The telemetry data also show that during winter, wild geese use agricultural fields and wetlands near captive bar-headed geese and chicken farms where outbreaks have occurred."........

Posted by: Kelly      Read more         Source


March 20, 2011, 10:16 PM CT

Researchers urge more prominent role for zoos

Researchers urge more prominent role for zoos
Two examples of the success of captive breeding in supporting species protection: the Asiatic wild horse (Przewalskis horse) and the Californian condor, both whose risk status has been downgraded thanks to breeding at zoos.

Credit: Wikipedia Chuck Szmurlo / BS Thurner Hof

Of around seven land vertebrate species whose survival in the wild is threatened one is also kept in captivity. These and other data on the protection of species in zoos and aquaria have now been revealed by researchers at the Max Planck Institute for Demographic Research (MPIDR) in Rostock. Writing in the journal Science, the team of scientists and the International Species Information System (ISIS) advocate the establishment of targeted captive breeding programmes to supplement the protection of animals in the wild. To do this, zoos should team up in networks and shelter these animals, as a form of life insurance, until they can be released back into the wild.

The scientists used data from the International Species Information System (ISIS) to calculate how a number of of the endangered species can already be found at zoological gardens: 20 to 25 percent of all endangered mammal species are kept at zoos. The overall figure for birds is only slightly less than that, but is much lower for avian species that are acutely at risk of extinction: only nine percent of these are found in captivity. Only three percent of endangered amphibian species are kept in captivity.

The role of zoos for species conservation must not be underestimated, Dalia Conde and Alexander Scheuerlein have stressed. "While it is true that the number of endangered species and individual animals at any one zoo is small", say the biologists, who conduct their research at the MPIDR's Laboratory of Evolutionary Biodemography, "if several institutions link up, zoological gardens will have a considerable collective potential to breed endangered animal species."........

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March 18, 2011, 10:18 PM CT

Accountants of the animal kingdom

Accountants of the animal kingdom
A puzzling example of altruism in nature has been debunked with scientists showing that purple-crowned fairy wrens are in reality cunningly planning for their own future when they assist in raising other birds' young by balancing the amount of assistance they give with the benefits they expect to receive in the future.

Dr Anne Peters, of the Monash University School of Biological Sciences, together with co-authors Sjouke Kingma from the Max Planck Institute for Ornithology and Michelle L. Hall of the Australian National University, have conducted a long term study of the cooperative breeding behaviour of fairy-wrens in tropical Australia.

The results, reported in the prestigious journal The American Naturalist, show that helpers are not motivated by kindness.

"The study showed that the seemingly selfless little helpers are in fact carefully calculating accountants" said Dr Peters, senior author of the study.

Cooperative breeding, where birds apparently selflessly raise others' offspring, has long perplexed biologists as this behaviour runs counter to Darwin's theory of natural selection, which predicts that individuals invest only in their own reproduction.

Fairy-wrens are habitual cooperative breeders. The helpers are generally older silblings or half-siblings of the current nestlings, and their behaviour is likely explained by an instinctive desire to see more of their shared genes entering the gene pool.........

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March 18, 2011, 6:26 PM CT

Gender roles in animals

Gender roles in animals
In a recent study published in "Animal Behaviour", biology scientists Kristina Karlsson Green and Josefin Madjidian at Lund University in Sweden have shown that animals' and plants' traits and behaviour in sexual conflicts are coloured by a human viewpoint. They want to raise awareness of the issue and provoke discussion among their colleagues in order to promote objectivity and broaden the research field.

Lund scientists Kristina Karlsson Green and Josefin Madjidian have studied and measured how male and female traits and behaviour in animals' and plants' sexual conflicts are described in academic literature and also what parameters are incorporated for each sex in mathematical models of sexual conflict.

"We have found evidence of choices and interpretations that may build on researchers' own, possibly subconscious, perception of male and female. We have now identified and quantified terms used to describe male and female in sexual conflict research and seen that different terms are used depending on the sex being described. It is not just something we think and suppose", says Kristina Karlsson Green from the Department of Biology at Lund University.

Sexual conflicts among animals and plants mean that the male and the female disagree in various ways on mating and the raising of young. Research on these sexual conflicts is an area that is growing rapidly. Therefore, it is particularly important to make other scientists aware of and alert to the fact that their own frames of reference pose a risk, say Kristina Karlsson Green and Josefin Madjidian.........

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March 18, 2011, 6:23 PM CT

Pollen also appears outside flowering season

Pollen also appears outside flowering season
A pollen trap.

Credit: AeroUEx

"There is of course a very close relationship between the moment at which pollen is released by plants and the data gathered by the traps used to measure these grains, but this is not always the case", Rafael Tormo, a botanist from the University of Extremadura and co-author of the paper, tells SINC.

His team found delays or advances of up to a week between the time when the pollen of allergenic grass species (from genuses such as Poa, Agrostis, Bromus and Avena) and cupressaceae (cypresses and Arizona pine) are present in the air and their flowering period.

As per the study, which has been reported in the International Journal of Biometeorology, these differences are probably due to the phenomenon of "resuspension" of the grains, caused by the wind and by pollen being transported from distant sources.

"Now, for example, the Holm oaks in Extremadura have not yet flowered, but those in Andalusia have done. If the wind blows from the south, the pollen traps in Extremadura will already be able to detect Holm oak pollen", explains Tormo, who highlights the importance of understanding the phenology of plant flowering in order to draw up precise pollen prognoses for people with allergies.

On the Iberian Peninsula and in the rest of Europe, the process of flowering moves from south to north, in such a way that the pollen traps "anticipate flowering" if the wind blows from the south. Conversely, if the wind blows from the north they may record pollen from more northerly latitudes even if the pollination period in the region they are located in is already over.........

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March 17, 2011, 11:05 PM CT

Optimizing yield and fruit size of figs

Optimizing yield and fruit size of figs
This is a photo showing Breba figs developing on one-year-old shoots.

Credit: Photo by Hein Gerber

The common fig is a subtropical, deciduous fruit tree grown in most Mediterranean-type climates. Eventhough some think that figs appears to be the oldest cultivated fruit species on earth, global expansion of fig crops has been hindered by the narrow research base pertaining to production practices and the limited number of fig cultivars currently available. Recently, three black figs were established in the Mediterranean-type climate of Western Cape Province of South Africa to provide fruit for fresh markets throughout South Africa and Europe.

Hein J. Gerber, Willem J. Steyn, and Karen I. Theron from the Department of Horticultural Science at South Africa's University of Stellenbosch reported on a study they conducted on three fig cultivars in HortScience. The research, conducted as part of Gerber's MScAgric degree requirements, was developed to establish the optimum 1-year-old shoot length to maximize fig fruit yield and quality.

"To maximize yield of good-quality fruit, the most productive shoot lengths (in terms of yield and fruit size) should be determined and strategies devised to maximize the number of these shoots on trees on an annual basis. It is important to study the phenological characteristics of a cultivar to establish optimum shoot characteristics", said Theron, corresponding author of the study. "The objective of our research was to identify the most suitable types of shoots and complete a detailed, comparative study of processes such as budbreak, shoot growth, and yield for each shoot length category".........

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March 17, 2011, 10:58 PM CT

Systems Biology and Cellular Networking

Systems Biology and Cellular Networking
Systems biology is the classic whole being greater than the sum of its parts, where researchers seek to understand how complex organisms emerge from the interactions of the individual elements that make up its constituent cells.
Systems biology is a holistic approach to the study of how a living organism emerges from the interactions of the individual elements that make up its constituent cells. Embracing a broad range of disciplines, this field of science that is just beginning to come into public prominence holds promise for advances in many important areas, including safer, more effective pharmaceuticals, improved environmental remediation, and clean, green, sustainable energy. However, the most profound impact of systems biology, as per one of its foremost practitioners, is that it might one day provide an answer to the central question: What is life?

Adam Arkin, director of the Physical Biosciences Division of the U.S. Department of Energy (DOE)'s Lawrence Berkeley National Laboratory and a leading computational biologist, is the corresponding author of an essay in the journal Cell which describes in detail key technologies and insights that are advancing systems biology research. The paper is titled "Network News:Innovations in 21st Century Systems Biology." Co-authoring the article is David Schaffer, a chemical engineer with Berkeley Lab's Physical Biosciences Division. Both Arkin and Schaffer also hold appointments with the University of California (UC) Berkeley.

"System biology aims to understand how individual elements of the cell generate behaviors that allow survival in changeable environments, and collective cellular organization into structured communities," Arkin says. "Ultimately, these cellular networks assemble into larger population networks to form large-scale ecologies and thinking machines, such as humans".........

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March 17, 2011, 10:53 PM CT

Multimedia in nursery management

Multimedia in nursery management
Instructional multimedia can be effectively used to create virtual field trips in a variety of horticulture-related classes.

Credit: Photo courtesy of Amy N. Wright

Students at land-grant universities are a major source of educated, highly qualified employees for the U.S. nursery industry. To prepare future employees for work in "green" occupations, land-grant institutions have traditionally offered classes in nursery management and production, but availability of qualified faculty, integration of departments, and cutbacks in horticulture programs have contributed to a reduction in the number of nursery management and production (NMP) courses being offered.

In a recent issue of HortTechnology, Amy N. Wright, James A. Robbins, and Mengmeng Gu report on an online survey they designed to gather information about nursery management and production (NMP) course content and enrollment, attitudes regarding the use of multimedia resources in the classroom, and opinions about the use of virtual field trips to supplement or replace traditional field trips.

To find out more about current practices in NMP, a survey was sent to instructors of courses that cover topics in NMP at 97 institutions in the U.S. As per Wright, corresponding author of the study; "Results reflected current organizational and curriculum changes that have impacted traditional horticulture courses such as NMP and in a number of cases have resulted in the merging of NMP courses with other courses such as greenhouse or garden center management." Most of the respondents indicated that the NMP course in their department included at least one field trip.........

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March 15, 2011, 10:39 PM CT

Dairy Farmer fInds Unusual Forage Grass

Dairy Farmer fInds Unusual Forage Grass
A U.S. Department of Agriculture (USDA) grass breeder has rediscovered a forage grass that seems just right for today's intensive rotational grazing.

A farmer's report of an unusual forage grass led Michael Casler, an Agricultural Research Service (ARS) geneticist at the agency's U.S. Dairy Forage Research Center in Madison, Wis., to identify the grass as meadow fescue. Meadow fescue has been long forgotten, eventhough it was popular after being introduced about 50 to 60 years before tall fescue.

ARS is USDA's principal intramural scientific research agency.

Casler has developed a new variety of meadow fescue called Hidden Valley, and its seed is being grown for future release.

Non-toxic fungi called endophytes live inside meadow fescue, helping it survive heat, drought and pests. Unlike the toxic endophytes that inhabit a number of commercial varieties of tall fescue and ryegrass, meadow fescue does not poison livestock.

Charles Opitz found the grass growing in the deep shade of a remnant oak savannah on his dairy farm near Mineral Point, Wis. He reported that the cows love it and produce more milk when they eat it. Casler used DNA markers to identify Opitz's find.

Meadow fescue is very winter-hardy and persistent, having survived decades of farming. It emerged from oak savannah refuges to dominate a number of pastures in the Midwest's driftless region, named for its lack of glacial drift, the material left behind by retreating continental glaciers.........

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March 15, 2011, 10:06 PM CT

Casey Dunn to Receive NSF Waterman Award

Casey Dunn to Receive NSF Waterman Award
The National Science Foundation (NSF) has named its awardee for this year's Alan T. Waterman Award: Casey Dunn, a biologist at Brown University.

Dunn's work involves genome analyses to better understand relationships between groups of animals.  He investigates the origins of biological complexity through work with deep-sea creatures called siphonophores. His research holds clues about how complex multicellular organisms, including humans, were formed.

Dunn will receive $500,000 over three years to continue his studies of animal evolution.

"The Waterman Award is designed to recognize outstanding young scientists like Casey Dunn," said NSF Director Subra Suresh. "His research has already made substantial contributions to our understanding of the origins of a diversity of life. His insights should further this important field of study in the years to come.".

Dunn serves as assistant professor of biology in the Department of Ecology and Evolutionary Biology at Brown University where he also runs the Dunn Lab, which investigates how evolution has produced a diversity of life.

The lab primarily studies morphology, a branch of biology that deals with the form and structure of animals. Research there also pursues learning about the actual history of life on Earth, as well as the general properties of evolution that have contributed to life's historical patterns. The type of questions the lab asks require marine, laboratory and computational work.........

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March 15, 2011, 7:41 AM CT

How the Slime Mold Gets Organized

How the Slime Mold Gets Organized
When food is scarce, the separate cells of the slime mold aggregate and form what is called a fruiting body. Cells at the tip of the fruiting body organize into a formation very similar to the epithelial layer of cells found in many organs of higher animals. Researchers found that the proteins responsible for organizing cells at the tip of the slime mold's fruiting body are genetically very similar to those that perform the same function in animal cells.

Credit: Zina Deretsky, National Science Foundation

The so-called cellular slime mold, a unicellular organism that may transition into a multicellular organism under stress, has just been found to have a tissue structure that was previously thought to exist only in more sophisticated animals. What's more, two proteins that are needed by the slime mold to form this structure are similar to those that perform the same function in more sophistical animals.

Shortly after an animal embryo forms, it develops a single layer of cells that, shaped like a hollow ball, is empty at its center. Acting as a kind of "man behind the curtain" that directs these cells to organize into this hollow formation are several proteins that help each cell touch its neighbors but keep its top surface exposed to the formation's empty interior.

Even after animals grow beyond the embryo stage, the cells in a number of organs of their bodies maintain this type of hollow structure. These organs include those in the digestive tracts of animals, which feature a layer of cells, called epithelial cells, that face inward to form a hollow structure and are shaped asymmetrically to give organs their directionality. For example, the asymmetric epithelial cells of animal intestines face inward to form a hollow structure through which nutrients are absorbed. Likewise, the asymmetric epithelial cells of animal glands, such as salivary and endocrine glands, also face inward to form a hollow structure. But instead of absorbing substances as do the epithelial cells of animal intestines, these glandular epithelial cells secrete into their hollow structure substances that they produce.........

Posted by: Janet      Read more         Source


March 13, 2011, 11:47 AM CT

Host change alters toxic cocktail

Host change alters toxic cocktail
Adult Chrysomela lapponica beetle.

Credit: MPI for Chemical Ecology/Kirsch



Leaf beetles fascinate us because of their amazing variety of shapes and rich coloring. Their larvae, however, are dangerous plant pests. Larvae of the leaf beetle Chrysomela lapponica attack two different tree species: willow and birch. To fend off predator attacks, the beetle larvae produce toxic butyric acid esters or salicylaldehyde, whose precursors they ingest with their leafy food. Researchers of the Max Planck Institute for Chemical Ecology in Jena, Gera number of, now observed that a fundamental change in the genome has emerged in beetles that have specialized on birch: The activity of the salicylaldehyde producing enzyme salicyl alcohol oxidase (SAO) is missing in these populations, whereas it is present in willow feeders. For birch beetles the loss of this enzyme and hereby the loss of salicylaldehyde is advantageous: the enzyme is not needed anymore because its substrate salicyl alcohol is only present in willow leaves, but not in birch. Birch beetles can therefore save resources instead of costly producing the enzyme. First and foremost, however, the loss of salicylaldehyde also means that birch feeding populations do not betray themselves to their own enemies anymore, who can trace them because of the odorous substance. (PNAS Early Edition, DOI 10.1073/pnas.1013846108).........

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March 13, 2011, 11:41 AM CT

Around 40 percent of hake is mislabeled

Around 40 percent of hake is mislabeled
The DNA studies carried out by a team of Spanish and Greek researchers, and reported in the Journal of Agricultural and Food Chemistry, show that more than 30% of the hake products sold in Spain and Greece are wrongly labelled.

"We have observed that hake caught in Africa are being labelled as American or European, meaning consumers pay a higher price for them", Eva Garc�a V�zquez, a professor at the University of Oviedo (Spain) and co-author of the study, tells SINC.

The scientists analysed 93 packages of fresh hake and several frozen brands in various hypermarkets between 2004 and 2006. After comparing what appeared on the label with the DNA results, it was observed that 31.5% of the batches were mislabelled with the wrong scientific name for the hake, or gave the wrong place of origin.

The study was repeated in 2010 with a further 18 batches, confirming that the information appearing on 38.9% of labels was wrong. For example, species from South Africa, such as Merluccius capensis, were labelled as hake from South America (M. hubbsi) or as the only hake species that exists in European waters (M. merluccius). The worst-labelled products were those containing the fillets or tails of these fish.

This error could be due to confusion during the marking of fish in distribution centres, but it is curious that the "cheap" African hake are the ones that are labelled as the "expensive" European or American ones, and not the other way around, which is why the study suggests that fraud is being committed.........

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March 12, 2011, 9:57 PM CT

Mouse Nose Nerve Cells Mature After Birth

Mouse Nose Nerve Cells Mature After Birth
For rodent pups, bonding with mom isn't hard-wired in the womb. It develops over the first few weeks of life, which is achieved by their maturing sense of smell, possibly allowing these mammals a survival advantage by learning to identify mother, siblings, and home.

Blended electrophysiological, biochemical, and behavioral experiments, Minghong Ma, PhD, an associate Professor of Neuroscience at the University of Pennsylvania School of Medicine, led a study published in a recent issue of the Journal of Neuroscience. With students Anderson Lee and Jiwei He, she demonstrated that neurons in the noses of mice mature after birth.

Using patch-clamping - a technique that measures electrical signals at the cellular level -- Ma's team observed that between birth and day 30 of development, normal neurons become six times more sensitive to their sibling's scent, in this case, a fragrance called lyral. In addition, the mice transition from a relative indiscriminate response to different odors to being highly attuned to one specific smell. They also respond to that specific odor with a faster speed over time.

The olfactory marker protein (OMP) likely mediates this developmental maturation. In olfactory sensory neurons lacking OMPs, response fails to speed up over 30 days as in comparison to normal neurons. The authors suggest this could be due to altered intracellular communication, since loss of the protein is linked to decreased phosphorylation of an associated enzyme called adenylate cyclase, a key player in the chemical signaling underlying the sense of smell.........

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March 10, 2011, 7:41 AM CT

Bonobos and Chimpanzees

Bonobos and Chimpanzees
Brian Hare, assistant professor of evolutionary anthropology at Duke University, spends several months of the year in the Democratic Republic of Congo, where he studies bonobos. He focuses on their behavior, specifically on how they solve problems and interact with other bonobos. Bonobos are genetically close to humans, yet most people know very little about them. Recently, Hare and his colleagues found that bonobos are natural sharers. The researchers' work described how bonobos enjoy sharing food with other bonobos, and never outgrow their willingness to do so--unlike chimpanzees that become more selfish when they reach adulthood.
Humans share 98.7 percent of our DNA with chimpanzees, but we share one important similarity with one species of chimp, the common chimpanzee, that we don't share with the other, the bonobo. That similarity is violence. While humans and the common chimpanzee wage war and kill each other, bonobos do not. "There has never been a recorded case in captivity or in the wild of a bonobo killing another bonobo," notes anthropologist Brian Hare.

Hare is an assistant professor in evolutionary anthropology at Duke University. With support from the National Science Foundation (NSF), he and his wife and colleague, Vanessa Woods, studied bonobo behavior at Lola ya Bonobo in the Democratic Republic of the Congo, an orphanage for young bonobos whose parents were killed for the bush meat trade. The war-torn Congo is the only place in the world where these endangered apes can be found.

"We go to this sanctuary and we play these fun problem-solving games with them to just try and get inside their heads and figure out exactly how they think," says Woods. "They're wonderful animals to be correlation to. It's a shame so few people have heard of them."

Woods is author of the book "Bonobo Handshake," a memoir about her experiences with these peaceful, playful primates, and some of the differences she noted between bonobos and common chimpanzees.........

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March 7, 2011, 7:19 AM CT

Environmental impact of animal waste

Environmental impact of animal waste
Swine houses and wastewater lagoon in North Carolina.

Credit: Terry A. Matheny

North and South Carolina have seen a steady increase in swine production over the last 15 years. In North Carolina alone, swine production generates approximately a quarter of the state's gross farm receipts. The presence of so a number of large-scale pig farms leads to the problem of proper animal waste disposal.

The most common practice in the Carolinas is storing animal waste in anaerobic lagoons. They are primarily used to concentrate and passively treat urine and feces but because of the widespread use of this practice, the environmental impact could be quite severe. Conflicting reports implicate lagoon sites to be responsible for high emission rates of nitrogen gas and volatized ammonia.

A team of ARS-USDA scientistsexamined a series of commercial, anaerobic, swine wastewater lagoons in North and South Carolina for genes involved in the nitrogen cycling process. Nitrification and denitrification are the parts of the process responsible for turning ammonia into nitrogen gas. After analyzing eight lagoons and measuring the abundance of four nitrogen cycling genes, scientists concluded that the denitrifying and nitrifying organisms were not active despite there being a thriving amount. Acidification and eutrophication of the surrounding ecosystem could be the result of prolonged exposure to volatilized ammonia.........

Posted by: Janet      Read more         Source


March 7, 2011, 7:17 AM CT

Cell's cytoskeleton and its surface receptors

Cell's cytoskeleton and its surface receptors
CD36 trajectories in a primary human macrophage from a 10 Hz/10 s single-molecule movie. Scale bar, 2 µm. Red, linear trajectories; cyan, isotropic trajectories. The linear motion of receptors, which depends on the actin meshwork and on microtubules, enhances receptor clustering in the absence of ligand, priming the macrophages to respond when exposed to ligand.

Credit: K. Jaqaman/Harvard Medical School.

New findings from scientists at Harvard Medical School in Boston and the Hospital for Sick Children in Toronto may shed light on the mechanisms that regulate the organization of receptors on the cell surface, a critical aspect of cell signaling not well understood at this time.

The group reports on their use of the macrophage protein CD36, a clustering-responsive class B scavenger receptor, as a model for studying the processes governing receptor clustering and organization. The protein is involved in many cellular and physiological functions that range from lipid metabolism to immunity, but it is unknown how the CD36 protein is organized in the cell (as monomers or as oligomers) and how that organization leads to its biological functions.

The scientists employed a combination of powerful tools: quantitative live-cell single-molecule imaging and biochemical/pharmacological approaches to study the dynamics, oligomerization and signaling of CD36 in primary human macrophages.

The group reports that movement of CD36 in the macrophage plasma membrane is regulated by the sub-membranous actin meshwork and by microtubules, demonstrating that these cytoskeletal components might play a critical role in receptor function, in general.

In terms of the impact of this research, lead researcher Khuloud Jaqaman says: "In the long run, establishing the relationship between receptor organization and cell signaling might aid in the development of drugs since receptors on the cell surface are the most accessible to pharmacological manipulation".........

Posted by: Janet      Read more         Source


February 22, 2011, 7:59 AM CT

In Absence of Western Lizards

In Absence of Western Lizards
Areas in California where Western fence lizards were removed had a subsequent drop in numbers of the ticks that transmit Lyme disease, researchers have discovered.

"Our expectation was that removing the lizards would increase the risk of Lyme disease, so we were surprised by this finding," said ecologist Andrea Swei, who conducted the study while she was a Ph.D. student in integrative biology at University of California, Berkeley.

"We observed that the result of lizard removal was a decrease in infected ticks, and therefore decreased Lyme disease risk to humans.".

Results of the study, published online today in the journal Proceedings of The Royal Society B, illustrate the complex role the Western fence lizard (Sceloporus occidentalis) plays in the abundance of disease-spreading ticks.

"This study demonstrates the complexity of infectious disease systems, and how the removal of one player--lizards--can affect disease risk," said Sam Scheiner, program director at the National Science Foundation (NSF), which funded the research through a joint Ecology of Infectious Diseases (EID) Program with the National Institutes of Health.

At NSF, the EID Program is supported by the Directorates for Biological Sciences and Geosciences.........

Posted by: Kelly      Read more         Source


February 22, 2011, 7:39 AM CT

Genome of the first of algal bloom species

Genome of the first of algal bloom species
This is an aerial view of Great South Bay, N.Y., during a brown tide bloom in June 2008. Billions of A. anophagefferens cells per liter crowded into the coastline and turned the water brown.

Credit: Suffolk County Department of Health Services

Algae play key roles in the global carbon cycle, helping sequester significant amounts of carbon. Some algal species can bloom, or become so numerous, that they discolor coastal waters and reduce the amount of light and oxygen available in the ecosystem. Previously known as "red tide," the term "harmful algal blooms" (HABs) was introduced two decades ago to note accumulation of algal biomass can sometimes also turn the ocean waters brown or green and disrupt an ecosystem, or that red-colored waters can sometimes be harmless.

Published online the week of February 21 in the Proceedings of the National Academy of Sciences, a team of scientists including U. S. Department of Energy (DOE) Joint Genome Institute (JGI) researchers led by Igor Grigoriev, reported the first complete and annotated genome sequence of a HAB species: Aureococcus anophagefferens

At first glance the marine phytoplankton, so tiny that 50 of them side by side span the width of a single human hair, seems innocuous. "It's a photosynthetic organism that plays a big role in carbon cycling, especially in coastal ecosystems, and can degrade organic carbon," noted first author Christopher Gobler of Stony Brook University. "When one of these blooms occurs and you get a billion cells per liter, it represents milligrams of carbon per liter, which is much higher than you typically see in coastal ecosystems." By sequencing its genome, or biological source code, researchers can examine its "parts list" for clues to Aureococcus' ability to capture CO2, survive in varying marine environments, exploit selenium in its proteins, and outgrow a number of of its competitors.........

Posted by: Janet      Read more         Source


February 14, 2011, 7:30 AM CT

Firefly Glow

Firefly Glow
Bioluminescent signal from firefly luciferase lights up mouse 30 minutes after injection with PCL-1, a probe that can be used to monitor hydrogen peroxide levels without harming the animal. (Photo from Christopher Chang group)
A unique new probe based on luciferase, the enzyme that gives fireflies their glow, enables scientists to monitor hydrogen peroxide levels in mice and thereby track the progression of infectious diseases or malignant tumors without harming the animals or even having to shave their fur. Developed by scientists with the Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California (UC) Berkeley, this new bioluminescent probe has already provided the first direct experimental evidence that hydrogen peroxide is continuously made even in a healthy animal.

"We are reporting the design, synthesis, and in vivo applications of Peroxy Caged Luciferin-1 (PCL-1), a chemoselective bioluminescent probe for the real-time detection of hydrogen peroxide within living animals," says Christopher Chang, a chemist who holds appointments with Berkeley Lab's Chemical Sciences Division and UC Berkeley's Chemistry Department, as well as the Howard Hughes Medical Institute.

Chang is the corresponding author of a paper in the Proceedings of the National Academy of Science (PNAS) that describes this research. The paper is titled "In vivo imaging of hydrogen peroxide production in a murine tumor model with a chemoselective bioluminescent reporter." Co-authoring with Chang were Genevieve Van de Bittner, Elena Dubikovskaya and Carolyn Bertozzi.........

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February 14, 2011, 7:13 AM CT

Pheromone increases foraging honey bees

Pheromone increases foraging honey bees
The application of a naturally occurring pheromone to honey bee test colonies increases colony growth resulting in stronger hives overall, as per a newly released study conducted by researchers at Oregon State University and Texas A&M University.

The study, which appeared this week in the journal, PLoS ONE, comes amid national concern over the existence of honey bee Colony Collapse Disorder (CCD) - a combination of events that result in the death of a bee colony. The causes behind CCD remain unknown, but scientists are focusing on four possible contributing factors: disease, pests, environmental conditions and nutrition.

As per Ramesh Sagili, coauthor on the study, "Division of labor linked to brood rearing in the honey bee: how does it translate to colony fitness?" resiliency to CCD appears to be increased through -better hive management and the use of optimal dose of brood pheromone -- a chemical released by honey bee larvae that communicates the presence of larvae in the colony to adult bees. Optimal dose of brood pheromone that can stimulate colony growth may vary depending on the colony size, time of application and several other factors.

The number of larvae present in the hive affects the ratio of adult foraging bees to non-foragers in favor of foragers, said Sagili. In our study, when low levels of brood pheromone were introduced to experimental hives foragers collected more pollen.........

Posted by: Kelly      Read more         Source


February 14, 2011, 6:48 AM CT

Vines overtaking the American tropics

Vines overtaking the American tropics
Sleeping Beauty's kingdom was overgrown by vines when she fell into a deep sleep. Scientists at the Smithsonian in Panama and the University of Wisconsin at Milwaukee received more than a million dollars from the U.S. National Science Foundation to discover why real vines are overtaking the American tropics. Data from eight sites show that vines are overgrowing trees in all cases.

"We are witnessing a fundamental structural change in the physical make-up of forests that will have a profound impact on the animals, human communities and businesses that depend on them for their livelihoods," said Stefan Schnitzer, research associate at the Smithsonian Tropical Research Institute in Panama and associate professor at the University of Wisconsin at Milwaukee.

Tropical forests hold more than half of the Earth's terrestrial species and much of the planet's carbon. If vines take over tropical forests the rules used to model ecosystem services, such as regulation of the water cycle and carbon storage may no longer apply.

"In 2002, Oliver Phillips, a professor at the University of Leeds in the U.K., published a controversial study claiming that vines were becoming more common in the Amazon," said Schnitzer. "By pulling together data from eight different studies, we now have irrefutable evidence that vines are on the rise not only in the Amazon, but throughout the American tropics".........

Posted by: Erica      Read more         Source


February 8, 2011, 6:50 AM CT

New findings in India's Bt cotton controversy

New findings in India's Bt cotton controversy
Crop yields from India's first genetically modified crop may have been overemphasized, as modest rises in crop yields may come at the expense of sustainable farm management, says a newly released study by a Washington University in St. Louis anthropologist.

The study, by Glenn Stone, PhD, professor of anthropology in Arts & Sciences, appears in the recent issue of the journal World Development.

In his paper, Stone compares village yields in 2003 and 2007, which conveniently had very similar levels of rainfall. "Cotton yields rose 18 percent with the adoption of genetically modified seeds," Stone says. "This is less than what has been reported in some economics studies, but much better than activists have claimed".

Pesticide sprayings also were down by 55 percent with the switch to genetically modified seed.

The crop in question is Bt cotton, genetically modified to produce its own insecticide. Approved for Indian farmers since 2002, the technology is being closely watched because it is the most widely planted GM crop on small farms in the developing world.

A number of activists and commentators, including England's Prince Charles, have accused Bt cotton of failing, ruining small farmers and causing suicides, Stone claims.

Several studies by economists, however, have shown Bt cotton farmers to be getting higher yields when compared with planters of conventional cotton.........

Posted by: Erica      Read more         Source


February 8, 2011, 6:39 AM CT

Phosphorus: Too Much or Too Little?

Phosphorus: Too Much or Too Little?
Fertilizer is rarely an inspiration for an art show, but this week at Arizona State University (ASU), sustainability, fertilizer and phosphorus scarcity will provide fuel for creative vision.

The art show, a juried exhibition with works by artists from Phoenix, Chicago, Portland and Houston, was created in partnership with researchers engaged in the Sustainable Phosphorus Summit, to take place Feb. 3-5, 2011, at ASU.

The summit is funded by the National Science Foundation (NSF).

Phosphate is a type of salt, which is mined for use in industry and as a fertilizer in agriculture.  It is an essential nutrient for life. Without it, people cannot grow food or build bones.

"We need to be concerned about the emerging threat of phosphorus scarcity, as well as the impacts of too much phosphorus through run-off into lakes and oceans," says Matt Kane, program director in NSF's Division of Environmental Biology, which supports the phosphorus summit.

Human activities have increased bioavailable phosphorus in the environment, or phosphorus from runoff, by some 400 percent, but the demand for it continues to increase. Meanwhile, phosphate available in mines--the only viable source--is on the decline.

The summit will explore phosphorus as a limited resource. It will bring together international experts to discuss issues ranging from the biological importance of phosphorus to concerns about national security.........

Posted by: Erica      Read more         Source


February 8, 2011, 6:38 AM CT

Wolverines Threatened by Climate Change

Wolverines Threatened by Climate Change
The aggressive wolverine may not be powerful enough to survive climate change in the contiguous United States, new research concludes.

Wolverine habitat in the northwestern United States is likely to warm dramatically if society continues to emit large amounts of greenhouse gases, as per new computer model simulations carried out at the National Center for Atmospheric Research (NCAR) in Boulder, Colo.

"The scientists have combined regional-scale climate projections with knowledge of a single species and its unique habitat to examine its vulnerability to a changing climate," says Sarah Ruth, program director in NSF's Directorate for Geosciences, which funds NCAR.

"This study is an example of how targeted climate predictions can produce new insights that could help us reduce the impact of future climate change on delicate ecosystems.".

Climate change is likely to imperil the wolverine in two ways: reducing or eliminating the springtime snow cover that wolverines rely on for raising their young, and increasing August temperatures well beyond what the species appears to be able to tolerate.

"Species that depend on snow cover for their survival are likely to be very vulnerable to climate change," says NCAR scientist Synte Peacock, the main author of a paper reporting the study's results.........

Posted by: Kelly      Read more         Source


February 8, 2011, 6:38 AM CT

The Most Genes in an Animal?

The Most Genes in an Animal?
Researchers have discovered that the animal with the most genes--about 31,000--is the near-microscopic freshwater crustacean Daphnia pulex, or water flea.

By comparison, humans have about 23,000 genes. Daphnia is the first crustacean to have its genome sequenced.

The water flea's genome is described in a Science paper published this week by members of the Daphnia Genomics Consortium, an international network of researchers led by the Center for Genomics and Bioinformatics (CGB) at Indiana University (IU) Bloomington and the U.S. Department of Energy's Joint Genome Institute.

"Daphnia's high gene number is largely because its genes are multiplying, creating copies at a higher rate than other species," said project leader and CGB genomics director John Colbourne.

"We estimate a rate that is three times greater than those of other invertebrates and 30 percent greater than that of humans.".

"This analysis of the Daphnia genome significantly advances our understanding of how an organism's genome interacts with its environment both to influence genome structure and to confer ecological and evolutionary success," says Saran Twombly, program director in the National Science Foundation (NSF)'s Division of Environmental Biology, which funded the research.........

Posted by: Kelly      Read more         Source


February 7, 2011, 3:51 PM CT

What keeps bears healthy while hibernating?

What keeps bears healthy while hibernating?
Hibernating, it turns out, is much more complicated than one might think.

Research reported in the latest issue of the journal Physiological and Biochemical Zoology illustrates a complex series of changes that occur in grizzly bears' hearts as they hibernate. The changes guard against complications that could arise from greatly reduced activity.

A grizzly hibernates five to six months of the year. During that time, its heart rate slows drastically from around 84 beats per minute when active to around 19. "If a human heart were to slow down like this, you'd see very detrimental things happening," said Bryan Rourke, a professor at Cal State Long Beach who worked on the research with his graduate student, Nathan Barrows.

Such a slow beat causes blood to pool in the heart's four chambers. In a human, the increased pressure would cause the chambers to stretch out. The dilated muscle would be weaker and less efficient, leading ultimately to congestive heart failure.

"Bears are able to avoid this," Rourke said, "and we're interested in how they do it".

Barrows and Rourke worked with Lynne Nelson and Charles Robbins, scientists at Washington State University who have been studying bears for years. They operate a facility at Washington State where grizzlies have been raised since birth and acclimated to echocardiogram testing. Research at the facility is providing crucial insight into the mysteries of the hibernating heart.........

Posted by: Kelly      Read more         Source


February 7, 2011, 7:58 AM CT

Clay-armored bubbles may have formed first protocells

Clay-armored bubbles may have formed first protocells
Fatty-acid liposomes compartmentalize inside a clay vesicle.

Credit: Photo courtesy of Anand Bala Subramaniam, Harvard School of Engineering and Applied Sciences.

A team of applied physicists at Harvard's School of Engineering and Applied Sciences (SEAS), Princeton, and Brandeis have demonstrated the formation of semipermeable vesicles from inorganic clay.

The research, published online this week in the journal Soft Matter, shows that clay vesicles provide an ideal container for the compartmentalization of complex organic molecules.

The authors say the discovery opens the possibility that primitive cells might have formed inside inorganic clay microcompartments.

"A lot of work, dating back several decades, explores the role of air bubbles in concentrating molecules and nanoparticles to allow interesting chemistry to occur," says main author Anand Bala Subramaniam, a doctoral candidate at SEAS.

"We have now provided a complete physical mechanism for the transition from a two-phase clay�air bubble system, which precludes any aqueous-phase chemistry, to a single aqueous-phase clay vesicle system," Subramaniam says, "creating a semipermeable vesicle from materials that are readily available in the environment".

"Clay-armored bubbles" form naturally when platelike particles of montmorillonite collect on the outer surface of air bubbles under water.

When the clay bubbles come into contact with simple organic liquids like ethanol and methanol, which have a lower surface tension than water, the liquid wets the overlapping plates. As the inner surface of the clay shell becomes wet, the disturbed air bubble inside dissolves.........

Posted by: Janet      Read more         Source


February 5, 2011, 7:23 AM CT

Scientists discover 7 new species of fish

Scientists discover 7 new species of fish
Female Starksia robertsoni -- one of the seven new species of blenny discovered by Smithsonian scientist Carole Baldwin and her team.

Credit: Smithsonian

Things are not always what they seem when it comes to fish�something researchers at the Smithsonian Institution and the Ocean Science Foundation are finding out. Using modern genetic analysis, combined with traditional examination of morphology, the researchers discovered that what were once believed to be three species of blenny in the genus Starksia are actually 10 distinct species. The team's findings appear in the scientific journal ZooKeys, Feb. 3.

Starksia blennies, small (less than 2 inches) fish with elongated bodies, generally native to shallow to moderately deep rock and coral reefs in the western Atlantic and eastern Pacific oceans, have been well-studied for more than 100 years. It would have been reasonable to assume that there was little about the group left to discover. Modern DNA barcoding techniques, however, suggested otherwise. While trying to match larval stages of coral reef fish to adults through DNA, the team of researchers noticed contradictions between the preliminary genetic data and the current species classification. Further investigation revealed that the team was dealing with a number of species new to science, including the new Starksia blennies.

"DNA analysis has offered science a great new resource to examine old questions," said Carole Baldwin, a zoologist at Smithsonian's National Museum of Natural History and main author of the paper. "This discovery is a perfect example of how DNA barcoding is illuminating species that we've missed before, especially small cryptic reef fishes like Starksia blennies. We don't know where we stand in terms of understanding species diversity, and our work suggests that current concepts appears to be surprisingly incomplete".........

Posted by: Kelly      Read more         Source


February 3, 2011, 7:37 AM CT

Oysters at risk

Oysters at risk
A new, wide-ranging survey that compares the past and present condition of oyster reefs around the globe finds that more than 90 percent of former reefs have been lost in most of the "bays" and ecoregions where the prized molluscs were formerly abundant. In a number of places, such as the Wadden Sea in Europe and Narragansett Bay, oysters are rated "functionally extinct," with fewer than 1 percent of former reefs persisting. The declines are in most cases a result of over-harvesting of wild populations and disease, often exacerbated by the introduction of non-native species.

Oysters have fueled coastal economies for centuries, and were once astoundingly abundant in favored areas. The new survey is reported in the recent issue of BioScience, the journal of the American Institute of Biological Sciences. It was conducted by an international team led by Michael W. Beck of The Nature Conservancy and the University of California, Santa Cruz. Beck's team examined oyster reefs across 144 bays and 44 ecoregions. It also studied historical records as well as national catch statistics. The survey suggests that about 85 percent of reefs worldwide have now been lost. The BioScience authors rate the condition of oysters as "poor" overall.

Most of the world's harvest of native oysters comes from just five ecoregions in North America, but even there, the condition of reefs is "poor" or worse, except in the Gulf of Mexico. Oyster fisheries there are "probably the last opportunity to achieve large-scale oyster reef conservation and sustainable fisheries," Beck and his coauthors write. Oysters provide important ecosystem services, such as water filtration, as well as food for people. The survey team argues for improved mapping efforts and the removal of incentives to over-exploitation. It also recommends that harvesting and further reef destruction should not be allowed wherever oysters are at less than 10 percent of their former abundance, unless it can be shown that these activities do not substantially affect reef recovery.........

Posted by: Kelly      Read more         Source


February 2, 2011, 10:31 PM CT

Biology milestone with hard X-ray laser

Biology milestone with hard X-ray laser
This image shows a schematic picture of the principle of femtosecond nanocrystallography. The Arizona State University protein beam injector, left, ejects photosystem I nanocrystals, which are so small that they are not visible under the microscope, in a fully hydrated stream of mother liquor. The stream of crystals interacts with the LCLS free-electron laser X-ray beam, where the crystals instantly explode. The free-electron laser X-ray beam is so strong that it destroys any solid material in its focus, forming a plasma that reaches temperatures higher than the inside of the sun. However, each laser pulse is so short that diffraction can be detected from each nanocrystal before it is destroyed. The size and shape of every single nanocrsytal can be reconstructed from the shape transforms, visible on the back detector image, that make reflections look like galaxies in the universe. With a frequency of 30 images per second, millions of diffraction patterns were collected. Data evaluation of just 10,000 diffraction patterns allowed the unraveling of the structure of the protein at molecular resolution, shown in the top right of this image.

Credit: Petra Fromme/Arizona State University

Unraveling the molecular basis of life is an age-old quest of humanity. A breakthrough towards this goal was reported in a pair of studies published Feb. 3 in the scientific journal Nature, detailing a new method developed to determine structures of biomolecules based on diffraction from protein nanocrystals that are so small that they are not even visible under the microscope. A tiny aerojet nozzle provides a fully hydrated constant stream of nanocrystals, both supplied from an interdisciplinary research team at Arizona State University.

These developments allowed an international team of nearly 90 scientists to collect more than 3 million exquisitely clear diffraction pattern "snapshots" just before the crystals exploded in the extreme strong ultra-short femtosecond X-ray pulses that are so intense it will ultimately vaporize any solid material in its focus. The experiments show the great potential of the X-ray free-electron laser � the Linac Coherent Light Source located at the Department of Energy's SLAC National Accelerator Laboratory � for new discoveries in biology and medicine.

"From the beginning, the resolution of images recorded by biologists has been limited by damage due to the radiation used," said physicist John C.H. Spence, a Regents' Professor in ASU's College of Liberal Arts and Sciences, one of the main authors of the studies. "But what happens if a pulse of imaging radiation is used that terminates before damage begins, yet contains sufficient photons to generate a useful scattering pattern?".........

Posted by: Janet      Read more         Source


February 2, 2011, 7:59 AM CT

Technology protects cotton from caterpillar's appetite

Technology protects cotton from caterpillar's appetite
Aerial photographs show that while the genetically modified crop survived intact, the unprotected plants were destroyed by the caterpillars.
image by: Jeremy Greene
The furry-looking insects start their development smaller than the head of a pin, but the caterpillars soon develop an appetite for cotton as big as the crop.

To demonstrate the insects' destructive power, Clemson University entomologist Jeremy Greene planted two cotton varieties - one genetically modified to provide protection from caterpillars, one not - in a demonstration field at the Edisto Research and Education Center.

The non-protected cotton was planted in a pattern that spelled the word "Tigers." Aerial photographs taken near harvest show that while the genetically modified crop survived intact, the unprotected plants provided three square meals a day for the crop-hungry herbivores.

The demonstration crop was planted in late May last year and grew through the summer.

"We wanted to show the kind of damage caterpillars can do when they're allowed to eat unprotected cotton freely," Greene said.

Cotton is a multimillion dollar crop in the Palmetto State involving hundreds of farms and thousands of jobs.

Nearly all cotton varieties planted in South Carolina contain genes found in the naturally occurring Bacillus thuringiensis, or Bt, that help the plant make its own insecticide.

Bt cotton is genetically modified with specific genes from Bacillus thuringiensis. Think of it as in-plant insecticide, Greene said. This technology has been commercially available since 1996, but improvements over the years have enhanced the control of major pests.........

Posted by: Erica      Read more         Source


February 2, 2011, 7:54 AM CT

Seeking Social Genes

Seeking Social Genes
In order understand the evolution of complex societies, scientists are sequencing the genomes of social insects. The most recent data, published this week in the Early Edition of Proceedings of the National Academy of Sciences, come from several species of ants, including the red harvester ant, Pogonomyrmex barbatus

A team, lead by Arizona State University organismal and systems biology professor Juergen Gadau, sequenced one of the genomes and set out to decipher which genes might be responsible for defining which ants work and which ants reproduce in a red harvester ant colony.

Division of labor and reproduction are two crucial characteristics researchers think are important to the evolution of social structure. "Having multiple independently evolved social genomes helps us to better understand which genes are involved in crucial social traits, because those should be highly conserved," Gadau said.

In addition to specialization of roles within a colony, scientists argue that development of methods to communicate information is another key aspect of eusociality, the extreme form of social behavior exhibited by certain bees, termites and ants.

This study was funded by the Division of Integrative Organismal Systems, part of the National Science Foundation's Biology Directorate. The Developmental Systems Cluster within the division supports research aimed at understanding how interacting developmental processes give rise to the emergent properties of organisms.........

Posted by: Kelly      Read more         Source


February 2, 2011, 7:52 AM CT

Home and Away: Are Invasive Plant Species Really That Special?

Home and Away: Are Invasive Plant Species Really That Special?
Invasive plant species are a serious environmental, economic and social problem worldwide. Their abundance can lead to lost native biodiversity and ecosystem functions, such as nutrient cycling.

Despite substantial research, however, little is known about why some species dominate new habitats over native plants that technically should have the advantage.

A common but rarely tested assumption, say biologists, is that these plants behave in a special way, making them more abundant when introduced into communities versus native plants that are already there.

If true, it would mean that biosecurity screening procedures need to address how species will behave once introduced to nonnative communities--very difficult to get right, scientists have found.

Researchers in a global collaboration called the Nutrient Network tested this "abundance assumption" for 26 plant species at 39 locations on four continents and found numerous problems with it.

The results are published in a paper in the current issue of the journal Ecology Letters

"Predicting success of invading species is difficult and uncertain, but very important," says Henry Gholz, program director in the National Science Foundation (NSF)'s Division of Environmental Biology, which funds the Nutrient Network.........

Posted by: Erica      Read more         Source


February 1, 2011, 7:53 AM CT

Road may disrupt migration

Road may disrupt migration
Building a highway through Serengeti National Park may devastate one of the world's last large-scale herd migrations and the region's ecosystem, as per new research by an international team of ecologists, including a University of Guelph professor.

The study by John Fryxell, a Guelph integrative biology professor, and four other researchers from the United States and Canada appears in a recent issue of PLoS ONE, a peer-evaluated international journal published by the Public Library of Science.

The scientists studied the effects of a proposal by the Tanzanian government to build a road that would bisect the northern portion of Serengeti National Park.

The Serengeti is one of few remaining places where large-scale migrations still occur, with nearly two million wildebeest, antelope and zebras looping the plains from Tanzania to Kenya and back each year.

The scientists observed that the road may cause a 35-per-cent reduction in wildebeest herds, plus direct and indirect effects on a number of other species and ecosystem processes.

The study did not consider other potential negative effects, such as car accidents, development or increased poaching, which would reduce herd numbers even further.

"This project has the potential to transform one of the greatest wonders in the world and one of the world's most iconic national parks," said Fryxell, who worked on the study with main author Ricardo Holdo from the University of Missouri and professors from the University of British Columbia, Princeton University and the University of Florida.........

Posted by: Janet      Read more         Source


January 28, 2011, 7:13 PM CT

What Makes an Orangutan an Orangutan

What Makes an Orangutan an Orangutan
For the first time, researchers have mapped the genome--the genetic code--of orangutans. This new tool appears to be used to support efforts to maintain the genetic diversity of captive and wild orangutans. The new map of the orangutan genome may also be used to help improve our understanding of the evolution of primates, including humans.

Partially funded by the National Science Foundation, the orangutan study appears in the Jan. 27 issue of Nature It was conducted by an international team of researchers led by Devin P. Locke of the Genome Center at Washington University.

Conservation implications

The name "orangutan" is derived from the Malay term, "man of the forest," a fitting moniker for one of our closest relatives.

There are two species of orangutans, defined primarily by their island of origin--either Sumatra or Borneo. The outlook for orangutan survival is currently dire because there are estimated to be only about 7,500 orangutans in Sumatra, where they are considered critically endangered, and only about 50,000 orangutans in Borneo, where they are considered endangered.

The endangerment status of orangutans is determined by the International Union for Conservation of Nature. .........

Posted by: Kelly      Read more         Source


January 28, 2011, 8:01 AM CT

A Mix of Tiny Gold and Viral Particles

A Mix of Tiny Gold and Viral Particles
Crystal lattice created by Sung Yong Park and colleagues (Illustration by Adolf Lachman)
Researchers have created a diamond-like lattice composed of gold nanoparticles and viral particles, woven together and held in place by strands of DNA. The structure - a distinctive mix of hard, metallic nanoparticles and organic viral pieces known as capsids, linked by the very stuff of life, DNA - marks a remarkable step in scientists' ability to combine an assortment of materials to create infinitesimal devices.

The research, done by researchers at the University of Rochester Medical Center, Scripps Research Institute, and Massachusetts Institute of Technology, was published recently in Nature Materials.

While people usually think of DNA as a blueprint for life, the team used DNA instead as a tool to guide the precise positioning of tiny particles just one-millionth of a centimeter across, using DNA to chaperone the particles.

Central to the work is the unique attraction of each of DNA's four chemical bases to just one other base. The researchers created specific pieces of DNA and then attached them to gold nanoparticles and viral particles, choosing the sequences and positioning them exactly to force the particles to arrange themselves into a crystal lattice.

When researchers mixed the particles, out of the brew emerged a sodium thallium crystal lattice. The device "self assembled" or literally built itself.........

Posted by: Janet      Read more         Source


January 28, 2011, 7:09 AM CT

Call for regulation of rare plant sales

Call for regulation of rare plant sales
eople are increasingly obtaining endangered or threatened plants, often illegally, and moving them outside their native range, as per an article in the journal Nature by Patrick Shirey and Gary Lamberti in the department of biological sciences at the University of Notre Dame.

As per their research last year, nearly 10 percent of the 753 plants listed as threatened and endangered under the US Endangered Species Act are being sold � or, at least, advertised � online. A number of buyers are horticulturalists who want flowers for their gardens. But increasingly, anecdotal evidence suggests that online shoppers include individuals and citizen groups involved in 'assisted colonization' projects. Here, species or genetic subtypes at risk of extinction are moved to non-native environments in which they might thrive � in the face of climate change, for instance.

Some private groups who want to protect the plants, such as the Torreya Guardians, are legally planting seedlings of the Florida torreya outside its current range to aid species conservation. However, Shirey urges government agencies to take more of a leadership role to monitor translocations because of the risks linked to introducing new species. The widespread transfer of endangered or threatened plants poses both environmental and economic risks.........

Posted by: Erica      Read more         Source


January 26, 2011, 7:21 AM CT

Tiger numbers could triple if large-scale landscapes are protected

Tiger numbers could triple if large-scale landscapes are protected
The tiger reserves of Asia could support more than 10,000 wild tigers � three times the current number � if they are managed as large-scale landscapes that allow for connectivity between core breeding sites, a new paper from some of the world's leading conservation researchers finds. The study, co-authored by World Wildlife Fund (WWF) scientists, is the first evaluation of the political commitment made by all 13 tiger range countries at November's historic tiger summit to double the tiger population across Asia by 2022.

"A Landscape-Based Conservation Strategy to Double the Wild Tiger Population" in the current issue of Conservation Letters, finds that the commitment to double tiger numbers is not only possible, but can be exceeded. However, it will take a global effort to ensure that core breeding reserves are maintained and connected via habitat corridors.

"In the midst of a crisis, it's tempting to circle the wagons and only protect a limited number of core protected areas, but we can and should do better," said Dr. Eric Dinerstein, Chief Scientist at WWF and a co-author of the study. "We absolutely need to stop the bleeding, the poaching of tigers and their prey in core breeding areas, but we need to go much further and secure larger tiger landscapes before it is too late".........

Posted by: Kelly      Read more         Source


January 25, 2011, 7:37 AM CT

Rhythmic vibrations guide caste development

Rhythmic vibrations guide caste development
Future queen or tireless toiler? A paper wasp's destiny may lie in the antennal drumbeats of its caretaker.

While feeding their colony's larvae, a paper wasp queen and other dominant females periodically beat their antennae in a rhythmic pattern against the nest chambers, a behavior known as antennal drumming.

The drumming behavior is clearly audible even to human listeners and has been observed for decades, prompting numerous hypotheses about its purpose, says Robert Jeanne, a professor emeritus of entomology at the University of Wisconsin-Madison. A number of have surmised that the drumming serves as a communication signal.

"It's a very conspicuous behavior. More than once I've discovered nests by hearing this behavior first," he says.

Jeanne and colleagues have now linked antennal drumming to development of social caste in a native paper wasp, Polistes fuscatus The new work is described as per a research findings reported in the Feb. 8 issue of Current Biology by Jeanne, UW-Madison postdoctoral researcher Sainath Suryanarayanan and John Hermanson, an engineer at the USDA Forest Products Laboratory in Madison, Wis.

Paper wasp colonies, like a number of other social insects, have distinct castes � workers, which build and maintain the nest and care for young, and gynes, which can become queens, lay eggs and establish new nests.........

Posted by: Kelly      Read more         Source


January 25, 2011, 7:29 AM CT

Wheat resistance genes failing

Wheat resistance genes failing
Wheat with resistance genes (left) shows little damage from Hessian flies, while a non-resistant variety (right) has been largely destroyed. (Photo courtesy of Dr. Michael Boyd, University of Missouri)

A number of of the genes that allow wheat to ward off Hessian flies are no longer effective in the southeastern United States, and care should be taken to ensure that resistance genes that so far haven't been utilized in commercial wheat lines are used prudently, as per U.S. Department of Agriculture and Purdue University scientists.

An analysis of wheat lines carrying resistance genes from dozens of locations throughout the Southeast showed that some give little or no resistance to the Hessian fly, a major pest of wheat that can cause millions of dollars in damage to wheat crops each year. Others, even those considered the most effective, are allowing wheat to become susceptible to the fly larvae, which feed on and kill the plants.

Wheat resistance genes recognize avirulent Hessian flies and activate a defense response that kills the fly larvae attacking the plant. However, this leads to strains of the fly that can overcome resistant wheat, much like insects becoming resistant to pesticides.

"The number of genes available to protect wheat is limited. There really aren't that a number of," said Richard Shukle, a research scientist with the USDA Agricultural Research Service Crop Production and Pest Control Research Unit and Purdue adjunct associate professor of entomology. "In the Southeast, having multiple generations of Hessian fly each year enhances the ability of these flies to overcome wheat's resistance".........

Posted by: Erica      Read more         Source


January 25, 2011, 7:20 AM CT

Improving soft shell harvest at Chesapeake Bay

Improving soft shell harvest at  Chesapeake Bay
A research effort designed to prevent the introduction of viruses to blue crabs in a research hatchery could end up helping Chesapeake Bay watermen improve their bottom line by reducing the number of soft shell crabs perishing before reaching the market. The findings, reported in the journal Diseases of Aquatic Organisms, shows that the transmission of a crab-specific virus in diseased and dying crabs likely occurs after the pre-molt (or 'peeler') crabs are removed from the wild and placed in soft-shell production facilities.

Crab mortality in soft shell production facilities is common, where it is typical for a quarter of all crabs to perish. Researchers attribute this high loss to the pressures crabs face as they are harvested, handled and placed in the facilities. When combined with the large number of animals living in a confined area, the potential for infectious diseases to spread among the crabs increases.

The team, led by University of Maryland Center for Environmental Science (UMCES) researchers, developed an innovative way to identify this crab virus solely by isolating its genetic material. Local watermen working in the soft-shell industry provided crabs to the Baltimore-based Institute of Marine and Environmental Technology (IMET) for examination.........

Posted by: Kelly      Read more         Source


January 21, 2011, 10:21 PM CT

How isolated are mountain top plant populations?

How isolated are mountain top plant populations?
This is Penstemon pachyphyllus and a bumblebee.

Credit: Courtesy of Andrea Kramer, Chicago Botanic Garden.

Do mountain tops act as sky islands for species that live at high elevations? Are plant populations on these mountain tops isolated from one another because the valleys between them act as barriers, or can pollinators act as bridges allowing genes to flow among distant populations?

Dr. Andrea Kramer and his colleagues from the Chicago Botanic Garden and the University of Illinois at Chicago were interested in pursuing these questions, especially for a genus of plants, Penstemon (Plantaginaceae), endemic to the Great Basin region of the Western United States. They published their findings in the recent issue of the American Journal of Botany (http://www.amjbot.org/cgi/content/full/98/1/109).

The flow of genetic material between populations maintains a species. In plants, if populations are separated by a landscape barrier such that pollen or seeds are unable to traverse either over or through, then the populations will begin to differ, either via mutations or genetic drift over time. However, habitat fragmentation and distance may not always be barriers, depending on the species and their modes of dispersal. And sometimes studies surprise us with their findings.

"These questions become increasingly important in places like the Great Basin as we consider the effects of climate change on native plant communities and the wildlife that depend upon them," Kramer commented. "The majority of the Great Basin region's species diversity is located on mountain tops, and as a generally warming climate drives species to higher elevations, the distance between mountaintop plant populations increases and more is mandatory of the pollinators in order to traverse the arid valleys between them."........

Posted by: Erica      Read more         Source

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