July 2, 2009, 10:05 PM CT

Learning from locusts

A similarity in brain disturbance between insects and people suffering from migraines, stroke and epilepsy points the way toward new drug therapies to address these conditions.

Queen's University biologists studying the locust have observed that these human disorders are linked by a brain disturbance during which nerve cells shut down. This also occurs in locusts when they go into a coma after exposure to extreme conditions such as high temperatures or lack of oxygen.

The Queen's study shows that the ability of the insects to resist entering the coma, and the speed of their recovery, can be manipulated using drugs that target one of the cellular signaling pathways in the brain.

"This suggests that similar therapys in humans might be able to modify the thresholds or severity of migraine and stroke," says Gary Armstrong, who is completing his PhD research in Biology professor Mel Robertson's laboratory. "What especially excites me is that in one of our locust models, inhibition of the targeted pathway completely suppresses the brain disturbance in 70 per cent of animals," adds Dr. Robertson.

The Queen's research team previously demonstrated that locusts go into a coma as a way of shutting down and conserving energy when conditions are dangerous. The cellular responses in the locust are similar to the response of brain cells at the onset of a migraine......... Posted by: Kelly      Read more         Source

June 25, 2009, 7:29 PM CT

Long-term apple scab resistance remains elusive

There are hundreds of choices when picking a crabapple tree from the nursery, but a Purdue University expert says only a handful are resistant to a widespread fungus or other serious diseases.

After reviewing 33 years of data, Janna Beckerman, a Purdue assistant professor of botany and plant pathology, observed that only five of 287 crabapple varieties had durable resistance to a serious disease of crabapple trees. The results of her study were reported in the recent issue of the journal HortScience

Beckerman said data on crabapple trees and apple scab had only been done on a year-by-year basis until now. Looking over a prolonged period gives scientists a better idea of which trees have historically maintained or lost apple scab resistance.

"Whenever new plants are released, they are often touted as disease-resistant, but they have only been tested for a few years," Beckerman said. "That isn't enough time. From this data, you could see that varieties that did well for the first few years after planting often developed scab within 10 years".

The Venturia inaequalis fungus produces black scab-like lesions on the fruit and leaves. Crabapple trees with scab tend to defoliate, or lose all their leaves, in early summer, a condition that can weaken and eventually kill the trees......... Posted by: Erica      Read more         Source

June 25, 2009, 6:05 PM CT

How piranhas got their teeth

How did piranhas the legendary freshwater fish with the razor bite get their telltale teeth? Scientists from Argentina, the United States and Venezuela have uncovered the jawbone of a striking transitional fossil that sheds light on this question. Named Megapiranha paranensis, this previously unknown fossil fish bridges the evolutionary gap between flesh-eating piranhas and their plant-eating cousins.

Present-day piranhas have a single row of triangular teeth, like the blade on a saw, explained the researchers. But their closest relatives a group of fishes usually known as pacus have two rows of square teeth, presumably for crushing fruits and seeds. "In modern piranhas the teeth are arranged in a single file," said Wasila Dahdul, a visiting scientist at the National Evolutionary Synthesis Center in North Carolina. "But in the relatives of piranhas which tend to be herbivorous fishes the teeth are in two rows," said Dahdul.

Megapiranha shows an intermediate pattern: it's teeth are arranged in a zig-zag row. This suggests that the two rows in pacus were compressed to form a single row in piranhas. "It almost looks like the teeth are migrating from the second row into the first row," said John Lundberg, curator at the Academy of Natural Sciences in Philadelphia and a co-author of the study......... Posted by: Kelly      Read more         Source

June 23, 2009, 5:00 PM CT

Prairie dogs and plants?

Prairie dogs may seem like harmless little creatures, but they can inflict serious injury on plants simply by snacking on them. Plants cannot flee from their furry predators, so how do they avoid becoming a prairie dog's lunch?.

Dr. John Freeman and his colleagues explore the role of metal hyperaccumulation in plant defense in the June 2009 issue of the American Journal of Botany Certain plants species growing on soils with high metal content (such as arsenic, copper, selenium, and lead) accumulate large quantities of metals in their leaves and stems. The purpose of this metal hyperaccumulation is not fully known, but metal hyperaccumulation may increase a plant's ability to respond to drought, compete with other plants, or provide a defense against bacteria, viruses, and animals.

"It is interesting to think about the effect of the prairie dog, which was an amazing ecosystem engineer on a very large scale here in North America," said Dr. Freeman, Colorado State University. "From their prehistoric ancestors the ground squirrel to the modern prairie dog, these animals may have driven the evolution of selenium hyperaccumulation as an elemental defense against herbivory in a number of different plant species".

Dr. Freeman's research focused on the role of selenium hyperaccumulation in Stanleya pinnata (prince's plume), a wildflower correlation to mustard plants. Eventhough low levels of selenium are essential for a number of animals, consumption of high levels is toxic. But just because an overdose of selenium is toxic to animals does not mean that the presence of high levels in leaves deters animals from eating the plants; prairie dogs may not know to avoid S. pinnata until it is too late. Few studies have addressed this question and whether metal hyperaccumulation actually acts as a deterrent......... Posted by: Kelly      Read more         Source

June 21, 2009, 8:56 PM CT

Domestication of Capsicum annuum chile pepper

Without the process of domestication, humans would still be hunters and gatherers, and modern civilization would look very different. Fortunately, for all of us who do not relish the thought of spending our days searching for nuts and berries, early civilizations successfully cultivated a number of species of animals and plants found in their surroundings. Current studies of the domestication of various species provide a fascinating glimpse into the past.

A recent article by Dr. Seung-Chul Kim and his colleagues in the June 2009 issue of the American Journal of Botany explores the domestication of chiles. These hot peppers, found in everything from hot chocolate to salsa, have long played an important role in the diets of Mesoamerican people, possibly since as early as ~8000 B.C. Capsicum annuum is one of five domesticated species of chiles and is notable as one of the primary components, along with maize, of the diet of Mesoamerican peoples. However, little has been known regarding the original location of domestication of C. annuum, the number of times it was domesticated, and the genetic diversity present in wild relatives.

To answer these questions, Dr. Kim and his team examined DNA sequence variation and patterns at three nuclear loci in a broad selection of semiwild and domesticated individuals. Dr. Kim et al. found a large amount of diversity in individuals from the Yucatan Peninsula, making this a center of diversity for chiles and possibly a location of C. annuum domestication. Previously, the eastern part of central Mexico had been considered to be the primary center of domestication of C. annuum On the basis of patterns in the sequence data, Dr. Kim et al. hypothesize that chiles were independently domesticated several times from geographically distant wild progenitors by different prehistoric cultures in Mexico, in contrast to maize and beans which appear to have been domesticated only once......... Posted by: Erica      Read more         Source

June 21, 2009, 8:52 PM CT

Plant Communication

-"To thine own self be true" may take on a new meaning-not with people or animal behavior but with plant behavior.

Plants engage in self-recognition and can communicate danger to their "clones" or genetically identical cuttings planted nearby, says professor Richard Karban of the Department of Entomology, University of California, Davis, in groundbreaking research reported in the current edition of Ecology Letters.

Karban and fellow scientist Kaori Shiojiri of the Center for Ecological Research, Kyoto University, Japan, observed that sagebrush responded to cues of self and non-self without physical contact.

The sagebrush communicated and cooperated with other branches of themselves to avoid being eaten by grasshoppers, Karban said. Eventhough the research is in its early stages, the researchers suspect that the plants warn their own kind of impending danger by emitting volatile cues. This may involve secreting chemicals that deter herbivores or make the plant less profitable for herbivores to eat, he said.

What this research means is that plants are "capable of more sophisticated behavior than we imagined," said Karban, who researches the interactions between herbivores (plant-eating organisms) and their host plants.

"Plants are capable of responding to complex cues that involve multiple stimuli," Karban said. "Plants not only respond to reliable cues in their environments but also produce cues that communicate with other plants and with other organisms, such as pollinators, seed disperses, herbivores and enemies of those herbivores"......... Posted by: Erica      Read more         Source

June 21, 2009, 8:48 PM CT

Dino-not-so-soaring

The largest animals ever to have walked the face of the earth may not have been as big as previously thought, reveals a paper published recently in the Zoological Society of London's Journal of Zoology

Scientists have discovered that the original statistical model used to calculate dinosaur mass is flawed, suggesting dinosaurs have been oversized.

Widely cited estimates for the mass of Apatosaurus louisae, one of the largest of the dinosaurs, may be double that of its actual mass (38 tonnes vs. 18 tonnes).

"Paleontologists have for 25 years used a published statistical model to estimate body weight of giant dinosaurs and other extraordinarily large animals in extinct lineages. By re-examining data in the original reference sample, we show that the statistical model is seriously flawed and that the giant dinosaurs probably were only about half as heavy as is generally believed" says Gary Packard from Colorado State University.

The new predictions have implications for numerous theories about the biology of dinosaurs, ranging from their energy metabolism to their food requirements and to their modes of locomotion......... Posted by: Kelly      Read more         Source

June 16, 2009, 9:45 PM CT

Global sunscreen won't save corals

Emergency plans to counteract global warming by artificially shading the Earth from incoming sunlight might lower the planet's temperature a few degrees, but such "geoengineering" solutions would do little to stop the acidification of the world oceans that threatens coral reefs and other marine life, report the authors of a newly released study in the journal Geophysical Research Letters*. The culprit is atmospheric carbon dioxide, which even in a cooler globe will continue to be absorbed by seawater, creating acidic conditions.

"There would be a slight reduction in this problem, because land plants would be expected to be able to grow more vigorously in a high CO₂, but cool world," says Ken Caldeira of the Carnegie Institution's Department of Global Ecology, a co-author of the study with main author Damon Matthews of Concordia University, Canada, and Carnegie geochemist Long Cao. Land plants and soils would hold onto more carbon in this scenario, so less would find its way into the oceans. "However this expansion of the land biosphere, while it's a slight help to ocean acidification is not enough to make a big difference".

A widely-discussed proposal for countering warming with geoengineering involves injecting small, reflective particles into the upper atmosphere. This would partially block incoming sunlight before it reached the Earth's surface, lowering global temperatures just as volcanic ash from the Mount Pinatubo did following its eruption in 1991. But critics have warned that such a scheme might also alter rainfall patterns, damage the planet's ozone layer, or have other unexpected effects......... Posted by: Janet      Read more         Source

June 12, 2009, 5:16 AM CT

Zebra mussels hang on while quagga mussels take over

The zebra mussels that have wreaked ecological havoc on the Great Lakes are harder to find these days not because they are dying off, but because they are being replaced by a cousin, the quagga mussel. But zebra mussels still dominate in fast-moving streams and rivers.

Research conducted by Suzanne Peyer, a doctoral candidate in the University of Wisconsin-Madison Department of Zoology, shows that physiological differences between the two species might determine which mollusk dominates in either calm or fast-moving waters.

"Zebra mussels quite rapidly colonized rivers close to the Great Lakes right after their introduction, within a year or two," Peyer explains. "Quagga mussels were introduced in the Great Lakes around 20 years ago, but they are not yet found in the rivers or tend to be present in low numbers".

The mussels are similar in a number of ways. Their habitats overlap, and both are suspension feeders that filter water to extract their food. But the cousin species are different in a number of ways, too. Zebra mussels prefer to attach to a hard surface, while quagga mussels can live on soft bottoms, such as sand or silt. Zebra mussels also prefer warmer water temperatures and do not grow as big as quagga mussels.

Peyer's research focused on the ability of the mussels to attach to underlying material. Both species attach to rocks, sand, silt or each other by producing tiny but strong "byssal" threads, string-like strands of protein. These threads act as an adhesive that enable the mussels to attach to surfaces, regardless of how slippery the surface is. Byssal threads are the reason mussels are so difficult to remove from boats or water intake pipes......... Posted by: Kelly      Read more         Source

June 10, 2009, 9:41 PM CT

Reviving American chestnuts may mitigate climate change

A Purdue University study shows that introducing a new hybrid of the American chestnut tree would not only bring back the all-but-extinct species, but also put a dent in the amount of carbon in the Earth's atmosphere.

Douglass Jacobs, an associate professor of forestry and natural resources, observed that American chestnuts grow much faster and larger than other hardwood species, allowing them to sequester more carbon than other trees over the same period. And since American chestnut trees are more often used for high-quality hardwood products such as furniture, they hold the carbon longer than wood used for paper or other low-grade materials.

"Maintaining or increasing forest cover has been identified as an important way to slow climate change," said Jacobs, whose paper was reported in the recent issue of the journal Forest Ecology and Management "The American chestnut is an incredibly fast-growing tree. Generally the faster a tree grows, the more carbon it is able to sequester. And when these trees are harvested and processed, the carbon can be stored in the hardwood products for decades, maybe longer".

At the beginning of the last century, the chestnut blight, caused by a fungus, rapidly spread throughout the American chestnut's natural range, which extended from southern New England and New York southwest to Alabama. About 50 years ago, the species was nearly gone......... Posted by: Erica      Read more         Source

June 10, 2009, 8:56 PM CT

The Secret of a Snake's Slither

Snake locomotion may seem simple in comparison to walking or galloping. But in reality, it's no easy task to move without legs. Prior research has assumed that snakes move by pushing off of rocks and debris around them. But a study published this week in the Proceedings of the National Academy of Sciences says that it's all in their design--specifically, their scales.

Overlapping belly scales provide friction with the ground that gives snakes a preferred direction of motion, like the motion of wheels or ice skates. Like wheels and ice skates, sliding forward for snakes takes less work than sliding sideways.

In addition, snakes aren't lying completely flat against the ground as they slither. They redistribute their weight as they move, concentrating it in areas where their bodies can get the most friction with the ground and therefore maximize thrust. In this way, snake slithering is not unlike human walking--we, too, shift our weight from left to right to enable us to move.

See the video........ Posted by: Kelly      Read more         Source

June 10, 2009, 8:50 PM CT

Evolution can occur in less than 10 years

How fast can evolution take place? In just a few years, as per a newly released study on guppies led by UC Riverside's Swanne Gordon, a graduate student in biology.

Gordon and her colleagues studied guppies small fresh-water fish biologists have studied for long from the Yarra River, Trinidad. They introduced the guppies into the nearby Damier River, in a section above a barrier waterfall that excluded all predators. The guppies and their descendents also colonized the lower portion of the stream, below the barrier waterfall, that contained natural predators.

Eight years later (less than 30 guppy generations), the scientists observed that the guppies in the low-predation environment above the barrier waterfall had adapted to their new environment by producing larger and fewer offspring with each reproductive cycle. No such adaptation was seen in the guppies that colonized the high-predation environment below the barrier waterfall.

"High-predation females invest more resources into current reproduction because a high rate of mortality, driven by predators, means these females may not get another chance to reproduce," explained Gordon, who works in the lab of David Reznick, a professor of biology. "Low-predation females, conversely, produce larger embryos because the larger babies are more competitive in the resource-limited environments typical of low-predation sites. Moreover, low-predation females produce fewer embryos not only because they have larger embryos but also because they invest fewer resources in current reproduction"......... Posted by: Kelly      Read more         Source

June 8, 2009, 10:19 PM CT

Complexity of animal mating choices

When female tiger salamanders choose a mate, it turns out that size does matter - tail size that is - and that's not the only factor they weigh.

Findings of a Purdue University study show that animals make more complex decisions about choosing mates than once thought. The results of Andrew DeWoody's study, released Monday (June 8) in the journal Molecular Ecology, refute a theory that animals use major histocompatibility complex (MHC) genes as the sole basis for mate choice. Immunologists have long known that MHC genes play key roles in the immune response, but more recently behavioral ecologists have postulated that animal mate choice is often based on MHC-type because of the function of those genes.

"Our data indicate that mate-choice decisions aren't solely dependent on MHC, tail length, body size or any other single factor," said DeWoody, a professor of genetics. "Mate choice is a complex process that takes a number of factors into account".

DeWoody and David Bos, a former postdoctoral assistant who is now a continuing lecturer at Purdue, set out to see how much MHC genes affected mate choice in wild animals. Most previous research showed that an animal would choose a mate with MHC that is the most divergent from its own so that offspring will have more effective immune systems......... Posted by: Kelly      Read more         Source

June 5, 2009, 4:57 AM CT

Bats recognize the individual voices of other bats

Bats can use the characteristics of other bats' voices to recognize each other, as per a research studyby scientists from the University of Tuebingen, Gera number of and the University of Applied Sciences in Konstanz, Gera number of. The study, published June 5 in the open-access journal PLoS Computational Biology, explains how bats use echolocation for more than just spatial knowledge.

The scientists first tested the ability of four greater mouse-eared bats to distinguish between the echolocation calls of other bats. After observing that the bats learned to discriminate the voices of other bats, they then programmed a computer model that reproduces the recognition behaviour of the bats. Analysis of the model suggests that the spectral energy distribution in the signals contains individual-specific information that allows one bat to recognize another.

Animals must recognize each other in order to engage in social behaviour. Vocal communication signals are helpful for recognizing individuals, particularly in nocturnal organisms such as bats. Little is known about how bats perform strenuous social tasks, such as remaining in a group when flying at high speeds in darkness, or avoiding interference between echolocation calls. The finding that bats can recognize other bats within their own species based on their echolocation calls may therefore have some significant implications......... Posted by: Kelly      Read more         Source

June 5, 2009, 4:50 AM CT

Corals' "Internal Communication"

Corals, it appears, have a genetic complexity that rivals that of humans, have sophisticated systems of biological communication that are being stressed by global change, and are only able to survive based on proper function of an intricate symbiotic relationship with algae that live within their bodies, say researchers in a paper published in this week's issue of the journal Science.

Disruptions in these biological and communication systems are the underlying cause of the coral bleaching and collapse of coral reef ecosystems around the world.

"We've known for some time the general functioning of corals and the problems they are facing from climate change," said Virginia Weis, a zoologist at Oregon State University.

"But until just recently, much less has been known about their fundamental biology, genome structure and internal communication. Only when we really understand how their physiology works will we know if they can adapt to climate changes, or ways we might help".

Reef-building corals are facing severe environmental threats, said Clayton Cook, program director in the National Science Foundation (NSF)'s Division of Integrative and Organismal Systems, which funded the research. "The most evident are bleaching events linked to higher ocean temperatures, and the effects of ocean acidification on reef-building......... Posted by: Janet      Read more         Source

June 5, 2009, 4:47 AM CT

Different genes cause loss of body parts

New research shows that when two species of stickleback fish evolved and lost their pelvises and body armor, the changes were caused by different genes in each species.

That surprised researchers, who expected the same genes would control the same changes in both related fish.

Results of the study, funded by the National Science Foundation (NSF)'s Divisions of Environmental Biology and Integrative Organismal Systems, are published online today in the journal Current Biology

"Earth's climate and biosphere are changing rapidly and in unpredictable ways," says Penny Firth, deputy director of NSF's Division of Environmental Biology. "A major challenge for biology is understanding the connections among evolving genomes, evolving populations and changing ecosystems. This research takes an important step by illuminating the genetic basis of evolutionary change in long-separated lineages".

Biologists knew that in a number of cases of evolution, "the same gene has been used over and over again--even in different species--to result in the same anatomy," says Mike Shapiro, first author of the paper and a biologist at the University of Utah. "What we are finding now is that different genes can have similar effects".

The findings shed new light on how evolution produces diversity in nature, and on the evolution of limb loss--and not just the loss of the pelvis and leg-like pelvic spines in certain sticklebacks......... Posted by: Kelly      Read more         Source

June 1, 2009, 7:17 PM CT

Coryphodon

Ancestors of tapirs and ancient cousins of rhinos living above the Arctic Circle 53 million years ago endured six months of darkness each year in a far milder climate than today that featured lush, swampy forests, as per a newly released study led by the University of Colorado at Boulder.

CU-Boulder Assistant Professor Jaelyn Eberle said the study shows several varieties of prehistoric mammals as heavy as 1,000 pounds each lived on what is today Ellesmere Island near Greenland on a summer diet of flowering plants, deciduous leaves and aquatic vegetation. But in winter's twilight they apparently switched over to foods like twigs, leaf litter, evergreen needles and fungi, said Eberle, curator of fossil vertebrates at the University of Colorado Museum of Natural History and chief study author.

The study has implications for the dispersal of early mammals across polar land bridges into North America and for modern mammals that likely will begin moving north if Earth's climate continues to warm. A paper on the subject co-authored by Henry Fricke of Colorado College in Colorado Springs and John Humphrey of the Colorado School of Mines in Golden appears in the recent issue of Geology

The team used an analysis of carbon and oxygen isotopes extracted from the fossil teeth of three varieties of mammals from Ellesmere Island -- a hippo-like, semi-aquatic creature known as Coryphodon, a second, smaller ancestor of today's tapirs and a third rhino-like mammal known as brontothere. Animal teeth are among the most valuable fossils in the high Arctic because they are extremely hard and better able to survive the harsh freeze-thaw cycles that occur each year, Eberle said......... Posted by: Kelly      Read more         Source

May 28, 2009, 5:12 AM CT

City rats loyal to their neighborhoods

n the rat race of life, one thing is certain: there's no place like home.

Now, a study published this week in the journal Molecular Ecology finds the same is as true for rats as for humans.

Eventhough inner city rodents appear to roam freely, most form distinct neighborhoods where they spend the majority of their lives.

Like any major city, Baltimore, Md., has a number of lively neighborhoods--each with its own personality. But researchers from the Johns Hopkins University Bloomberg School of Public Health say humans aren't the only Baltimoreans loyal to their 'hoods.

Rats typically stay close to home, rarely venturing more than a city block away. In the face of danger, however, some rodents can travel as far as seven miles to repopulate abandoned areas.

An understanding of how rats in urban areas are connected provides information about which populations may spread disease, as per Sam Scheiner, program director in the National Science Foundation (NSF)'s Division of Environmental Biology, which funded the research through the joint NSF-National Institutes of Health Ecology of Infectious Diseases program.

Baltimore's port was a once major delivery point for grain, likely how Norway rats were first introduced to the city. Norway rats, also called wharf rats, sewer rats or brown rats, can weigh nearly two pounds and transmit a variety of diseases to humans......... Posted by: Kelly      Read more         Source

May 24, 2009, 8:53 PM CT

Thanks to spillover from landscape corridors

Recently, images of melting sea ice and shrinking rainforests have highlighted the world's biodiversity crisis and made us aware of the need to find a balance between preserving natural ecosystems while still having enough land for human use.

"About 10 percent of the world's land surface is afforded formal protection. We need to manage that 10 percent as best as we possibly can to preserve biodiversity but also be mindful of human needs, such as food and fiber production," said Lars A. Brudvig, Ph.D., post-doctoral researcher in biology in Arts & Sciences at Washington University in St. Louis.

"One way to do this is by managing the land in a way that promotes biodiversity beyond the habitat's borders."

One of the most popular ways to manage landscapes fragmented by humans is to connect the isolated patches of habitat with skinny strips of land called corridors.

Brudvig and Ellen I. Damschen, Ph.D., assistant professor of biology at Washington University, in collaboration with scientists at the University of Washington, North Carolina State University and University of Florida, have discovered that the biodiversity in a patch of habitat can extend outside the borders of a protected area; this effect is magnified when the habitats are connected by corridors......... Posted by: Erica      Read more         Source

May 21, 2009, 6:10 AM CT

Contaminants in Marine Mammals' Brains

The most extensive study of pollutants in marine mammals' brains reveals that these animals are exposed to a hazardous cocktail of pesticides such as DDTs and PCBs, as well as emerging contaminants such as brominated flame retardants.

Eric Montie, the main author on the study currently in press and published online April 17 in Environmental Pollution, performed the research as a student in the Woods Hole Oceanographic Institution-MIT Joint Graduate Program in Oceanography and Ocean Engineering and as a postdoctoral fellow at the Woods Hole Oceanographic Institution (WHOI). The final data analysis and writing were conducted at College of Marine Science, University of South Florida, where Montie now works in David Mann's marine sensory biology lab.

Co-author Chris Reddy, an associate scientist in the WHOI Marine Chemistry and Geochemistry Department, describes the work as "groundbreaking because Eric measures a variety of different chemicals in animal tissues that had not been previously explored. It gives us greater insight into how these chemicals appears to behave in marine mammals."

The work represents a major collaborative effort between the laboratories of Reddy and Mark Hahn in the WHOI Biology Department, where Montie was a graduate student and post doc, as well as Robert Letcher at Environment Canada. Montie traveled to Environment Canada in Ottawa to learn the painstaking techniques mandatory to extract and to quantify more than 170 different pollutants and their metabolites. He then brought the methods back to WHOI and performed the analyses in Reddy's laboratory. Reddy describes the methods as extremely unforgiving and explains, "This is not making Toll House cookies. The fact that Eric pulled it off so seamlessly is amazing considering that he did this by himself far away from Ottawa"......... Posted by: Kelly      Read more         Source

May 21, 2009, 6:07 AM CT

Important Role For Junk Dna

Researchers have called it "junk DNA." They have long been perplexed by these extensive strands of genetic material that dominate the genome but seem to lack specific functions. Why would nature force the genome to carry so much excess baggage?.

Now scientists from Princeton University and Indiana University who have been studying the genome of a pond organism have observed that junk DNA may not be so junky after all. They have discovered that DNA sequences from regions of what had been viewed as the "dispensable genome" are actually performing functions that are central for the organism. They have concluded that the genes spur an almost acrobatic rearrangement of the entire genome that is necessary for the organism to grow.

It all happens very quickly. Genes called transposons in the single-celled pond-dwelling organism Oxytricha produce cell proteins known as transposases. During development, the transposons appear to first influence hundreds of thousands of DNA pieces to regroup. Then, when no longer needed, the organism cleverly erases the transposases from its genetic material, paring its genome to a slim 5 percent of its original load.

"The transposons actually perform a central role for the cell," said Laura Landweber, a professor of ecology and evolutionary biology at Princeton and an author of the study. "They stitch together the genes in working form." The work appeared in the May 15 edition of Science......... Posted by: Janet      Read more         Source

May 20, 2009, 7:34 PM CT

Endangered right whales found where presumed extinct

Using a system of underwater hydrophones that can record sounds from hundreds of miles away, a team of researchers from Oregon State University and the National Oceanic and Atmospheric Administration has documented the presence of endangered North Atlantic right whales in an area they were believed to be extinct.

The discovery is especially important, scientists say, because it is in an area that appears to be opened to shipping if the melting of polar ice continues, as expected.

Results of the study were presented this week at a meeting of the Acoustical Society of America in Portland, Ore.

The researchers are unsure of exactly how a number of whales were in the region, which is off the southern tip of Greenland and site of an important 19th-century whaling area called Cape Farewell Ground. But they recorded more than 2,000 right whale vocalizations in the region from July through December of 2007.

"The technology has enabled us to identify an important unstudied habitat for endangered right whales and raises the possibility that contrary to general belief a remnant of a central or eastern Atlantic stock of right whales still exists and might be viable," said David Mellinger, an assistant professor at OSU's Hatfield Marine Science Center in Newport and chief scientist of the project......... Posted by: Kelly      Read more         Source

May 20, 2009, 7:30 PM CT

Green fluorescent proteins in marine creature

Scientists at Scripps Institution of Oceanography at UC San Diego and the Salk Institute for Biological Studies have discovered a family of green fluorescent proteins (GFPs) in a primitive sea animal, along with new clues about the role of the proteins that has nothing to do with their famous glow.

GFPs recently gained international attention with the awarding of the 2008 Nobel Prize in Chemistry, shared by UC San Diego's Roger Tsien, as word spread of their extensive presence in nature as well as benefit to researchers. GFPs, originally isolated from a luminous jellyfish, have gained scientific ubiquity in uses ranging from biomedical tracers to probes for testing environmental quality. But while the value of GFPs in biomedicine and bioengineering has become evident, their diversity across the tree of life and their role in nature haven't been as easily deciphered.

New hints have emerged as Erin Bomati, a former postdoctoral researcher at Scripps Oceanography, Gerard Manning of the Salk Institute for Biological Studies and Scripps lead-scientist Dimitri Deheyn discovered the largest known family of GFPs. They found 16 related types of GFPs in amphioxus, a thin, non-luminous fish-like animal that lives in coastal areas and spends most of its time burrowed in ocean sand. The discovery, described in the journal BioMed Central (BMC) Evolutionary Biology, was made in Branchiostoma floridae, an amphioxus species collected off Tampa, Fla......... Posted by: Kelly      Read more         Source

May 20, 2009, 6:51 PM CT

Bird songs change with the landscape

When the going gets rough, the tough apparently sing slower.

As vegetation reclaimed formerly cleared land in California, Oregon and Washington over the last 35 years, male white-crowned sparrows have lowered their pitch and slowed down their singing so that their love songs would carry better through heavier foliage.

"This is the first time that anyone has shown that bird songs can shift with rapid changes in habitat," says biologist Elizabeth Derryberry who made the finding as part of her dissertation research at Duke University.

She compared recordings of individual birds in 15 different areas with some nearly forgotten recordings made at the same spots in the 1970s by a California Academy of Sciences researcher, and observed that the musical pitch and speed of the trill portion of the sparrows' short songs had dropped considerably. "I was really surprised to find that songs had changed in a similar way in so a number of different populations".

She then used archival aerial photography to see how the foliage had changed in a subset of those spots, and observed that the one population whose song hadn't slowed down lived in an area where the foliage hadn't changed either.

The physics is clear, but the biology is a little less certain. A lower, slower song suffers less reverberation in denser foliage and will be heard more accurately. In turn, that means it is more likely to be copied by young males who are choosing which song they will learn. Over generations, that should cause the song to slow down and drop in pitch as the foliage changes......... Posted by: Kelly      Read more         Source

May 20, 2009, 6:49 PM CT

Snail venoms reflect reduced competition

A study of venomous snails on remote Pacific islands reveals genetic underpinnings of an ecological phenomenon that has fascinated researchers since Darwin.

The research, by University of Michigan evolutionary biologists Tom Duda and Taehwan Lee, is scheduled to be published online May 20 in the open-access journal PLoS ONE

In the study, Duda and Lee explored ecological release, a phenomenon believed to be responsible for some of the most dramatic diversifications of living things in Earth's history. Ecological release occurs when a population is freed from the burden of competition, either because its competitors become extinct or because it colonizes a new area where few or no competitors are found. When this happens, the "released" population typically expands its diet or habitat, taking over resources that would be off-limits if competitors were present. This expansion is believed to drive the evolution of adaptations for taking advantage of the new resources, such as venoms tailored to a broader array of prey.

"Eventhough there are plenty of examples of populations expanding into a variety of niches after experiencing ecological release, little is known about the evolution of genes linked to this phenomenon," said Duda, an assistant professor in the U-M Department of Ecology and Evolutionary Biology......... Posted by: Kelly      Read more         Source

May 20, 2009, 6:27 PM CT

Small evolutionary shifts make big impacts

In the developing fetus, cell growth follows a very specific schedule. In the eye's retina, for example, cones -- which help distinguish color during the day -- develop before the more light-sensitive rods -- which are needed for night vision.

But minor differences in the timing of cell proliferation can explain the large differences found in the eyes of two species -- owl monkeys and capuchin monkeys -- that evolved from a common ancestor.

Scientists from Cornell, St. Jude's Children's Research Hospital in Tennessee and the Federal University of Para, Brazil, have found an evolutionary mechanism that provides insight into how important changes in brain structure of primates can evolve.

That evolution appears to proceed via simple genetic changes that affect the timing of development of brain regions, they report in a paper published May 18 online and in a future print issue of Proceedings of the National Academy of Sciences.

In both monkey species, the specialized eye cells develop in the growing embryo from a single retinal progenitor cell. In their basic design, the eyes of these primates have the capability and necessary architecture to be either nocturnal or diurnal, based on a species' ecological niche and needs, said Cornell neurobiologist and psychology expert Barbara Finlay......... Posted by: Kelly      Read more         Source

May 19, 2009, 5:11 AM CT

New insight into primate eye evolution

Scientists comparing the fetal development of the eye of the owl monkey with that of the capuchin monkey have observed that only a minor difference in the timing of cell proliferation can explain the multiple anatomical differences in the two kinds of eyes.

The findings help researchers understand how a structure as complex as the eye could change gradually through evolution, yet remain functional. The findings also offer a lesson in how seemingly simple genetic changes in the brain and nervous system could produce the multiple evolutionary changes seen in more advanced brains, without compromising function.

Analysis for this study waccording toformed at St. Jude Children's Research Hospital. The primates were housed at the Centro Nacional de Primates in Brazil. Contributing scientists at Cornell University and Universidade Federal do Par, Brazil, approved all procedures. The scientists published their findings in the early online issue of Proceedings of the National Academy of Sciences

"The molecular, cellular and genetic pathways that coordinate proliferation during development have been fine-tuned since the first multicellular organisms emerged millions of years ago," said Michael Dyer, Ph.D., member of St. Jude Developmental Neurobiology and the paper's first author. "When these pathways are deregulated during human development, one of the consequences is childhood cancer. Therefore, by studying how changes in the regulation of proliferation during development can lead to dramatic changes in form and function during evolution, we can gain a deeper understanding of these ancient pathways that lie at the heart of a number of pediatric cancers"......... Posted by: Kelly      Read more         Source

May 18, 2009, 5:32 AM CT

World's largest leatherback turtle population

An international team of researchers has identified a nesting population of leatherback sea turtles in Gabon, West Africa as the world's largest. The research, reported in the recent issue of Biological Conservation, involved country-wide land and aerial surveys that estimated a population of between 15,730 and 41,373 female turtles using the nesting beaches. The study highlights the importance of conservation work to manage key sites and protected areas in Gabon.

Leatherbacks are of profound conservation concern around the world after populations in the Indo-Pacific crashed by more than 90 percent in the 1980s and 1990s. The International Union for Conservation of Nature (IUCN) lists leatherback turtles as critically endangered globally, but detailed population evaluations in much of the Atlantic, particularly Africa, are lacking.

The research was led by the University of Exeter working in collaboration with the Wildlife Conservation Society (WCS) which spearheads the Gabon Sea Turtle Partnership, a network of organisations concerned with the protection of marine turtles in Gabon.

During three nesting seasons between 2002 and 2007, the team's members carried out the most comprehensive survey of marine turtles ever conducted in Gabon. This involved aerial surveys along Gabon's 600 km (372 mile) coast, using video to capture footage for assessment, and detailed ground-based monitoring. By covering the entire coastline, they were not only able to estimate the number of nests and nesting females, but also to identify the key sites for leatherback nesting, data which are crucial to developing conservation management plans for the species. Leatherbacks were first described nesting in Gabon in 1984......... Posted by: Kelly      Read more         Source

May 13, 2009, 5:25 AM CT

Predators ignore peculiar prey

Rare traits persist in a population because predators detect common forms of prey more easily. Scientists writing in the open access journal BMC Ecology observed that birds will target salamanders that look like the majority even reversing their behavior in response to alterations in the ratio of a distinguishing trait.

Benjamin Fitzpatrick, from the University of Tennessee, worked with Kim Shook and Reuben Izally to study the effects of the prevalence of a dorsal stripe among a group of model salamanders on the foraging behavior of a flock of Blue Jays. He said, "Maintenance of variation is a classic paradox in evolution because both selection and drift tend to remove variation from populations. If one form has an advantage, such as being harder to spot, it should replace all others. Likewise, random drift alone will eventually result in loss of all but one form when there are no fitness differences. There must therefore be some advantage that allows unusual traits to persist".

The authors placed a selection of food-bearing model salamanders into a field for six days, with striped models outnumbering the unstriped by nine to one, or vice versa. On test days, the numbers were evened out. In each case, Blue Jays were more likely to attack the models that had been most prevalent over the prior six-day period. As per Fitzpatrick, "We think that the different color forms represent different ways of blending in on the forest floor. Looking for something cryptic takes both concentration and practice. Predators concentrating on finding striped salamanders might not notice unstriped ones"......... Posted by: Kelly      Read more         Source

May 13, 2009, 5:10 AM CT

New dinosaur species possible

EdmontonThe discovery of a gruesome feeding frenzy that played out 73 million years ago in northwestern Alberta may also lead to the discovery of new dinosaur species in northwestern Alberta.

University of Alberta student Tetsuto Miyashita and Frederico Fanti, a paleontology graduate student from Italy, made the discovery near Grande Prairie, 450 kilometres northwest of Edmonton.

Miyashita and Fanti came across a nesting site and found the remains of baby, plant-eating dinosaurs and the teeth of a predator. The scientists matched the teeth to a Troodon, a raptor-like dinosaur about two metres in length. This finding has opened new doors in dinosaur research on this part of the continent: "It established that dinosaurs were nesting at this high latitude," said Miyashita. "It also shows for the first time a significant number of Troodons in the area [who] hunted hatchling dinosaurs".

Over the course of two summers of field work Miyashita and Fanti began building a theory that Grande Prairie is a "missing link" between known dinosaur species that existed much further to the north and south. "Previous to this there were no localities with a variety of dinosaurs and other animals between Alaska and southern Alberta," said Myiashita. The list of new finds for the area includes armoured and thick-headed plant eaters and fossilized freshwater fish and reptiles......... Posted by: Kelly      Read more         Source

May 12, 2009, 10:15 PM CT

Bacteria create aquatic superbugs

For bacteria in wastewater therapy plants, the stars align perfectly to create a hedonistic mating ground for antibiotic-resistant superbugs eventually discharged into streams and lakes.

In the first known study of its kind, Chuanwu Xi of the University of Michigan School of Public Health and his team sampled water containing the bacteria Acinetobacter at five sites in and near Ann Arbor's wastewater therapy plant.

They found the so-called superbugs-bacteria resistant to multiple antibiotics-up to 100 yards downstream from the discharge point into the Huron River. Xi stresses that while the finding appears to be disturbing, it is important to understand that much work is still needed to assess what risk, if any, the presence of superbugs in aquatic environments poses to humans.

"We still need to understand the link between aquatic and human multiple drug resistant bacteria," said Xi, assistant professor of public health.

Xi and his colleagues observed that while the total number of bacteria left in the final discharge effluent declined dramatically after therapy, the remaining bacteria was significantly more likely to resist multiple antibiotics than bacteria in water samples upstream. Some strains resisted as a number of as seven of eight antibiotics tested. The bacteria in samples taken 100 yards downstream also were more likely to resist multiple drugs than bacteria upstream......... Posted by: Janet      Read more         Source

May 12, 2009, 10:08 PM CT

Global warming driving Michigan mammals north

Some Michigan mammal species are rapidly expanding their ranges northward, apparently in response to climate change, a newly released study shows. In the process, these historically southern species are replacing their northern counterparts.

The finding, by scientists at the University of Michigan, Michigan State University and Ohio's Miami University, appears in the recent issue of the journal Global Change Biology.

"When you read about changes in flora and fauna correlation to climatic warming, most of what you read is either predictive-they're talking about things that are going to happen in the future-or it's restricted to single species living in extreme or remote environments, like polar bears in the Arctic," said main author Philip Myers, professor of ecology and evolutionary biology at U-M. "But this study documents things that are happening right now, here at home".

What will be the ultimate impact of Michigan's changing mammal communities?

"We're talking about the commonest mammals there, mammals that have considerable ecological impact," Myers said. "They disperse seeds, they eat seeds, they eat the insects that kill trees, they disperse the fungus that grows in tree roots that is necessary for trees to grow, and they're the prey base for a huge number of carnivorous birds, mammals and snakes. But we don't know enough about their natural history to know whether replacing a northern species with a southern equivalent is going to pass unnoticed or is going to be catastrophic. It could work either way......... Posted by: Kelly      Read more         Source

May 7, 2009, 10:18 PM CT

Northern Shrimp Populations in the North Atlantic

Even for Northern shrimp (Pandalus borealis), which support commercial fisheries worldwide, timing is everything in life. The tiny creatures, eaten in shrimp rolls and shrimp salad, occupy a pivotal role in the oceanic food chain and may serve as early indicators of changing climate due to their sensitivity to temperature. Northern shrimp also seem to have an uncanny sense of reproductive timing, releasing their larvae to match the arrival of food and thus maximizing larval survival.

In a study to be published May 8 in the journal Science, Anne Richards of NOAA's Northeast Fisheries Science Center (NEFSC) laboratory in Woods Hole, Mass. and international colleagues reviewed the timing of the annual shrimp hatch between 1998 and 2007 in populations or stocks at different latitudes across the North Atlantic Ocean from Maine to Norway. The scientists also estimated the timing of spring phytoplankton blooms - the major source of food for the shrimp larvae - in each location using satellite images that show biological productivity in surface waters, usually called ocean color.

"In the Gulf of Maine we have seen years when there is a good match in timing between when shrimp larvae are released and when the annual spring bloom begins. In these years larvae tend to have high survival rates, resulting in large year classes and a very successful fishery," said Richards, who has been studying Northern shrimp for almost two decades. "In other years that timing is off, leading to lower survival rates and a poorer fishery. The match or mismatch between the larvae and their food may be a key factor in shrimp production."........ Posted by: Kelly      Read more         Source

May 7, 2009, 9:35 PM CT

Gecko vision

Rockville, MD Nocturnal geckos are among the very few living creatures able to see colors at night, and scientists' discovery of series of distinct concentric zones may lead to insight into better cameras and contact lenses.

The key to the exceptional night vision of the nocturnal helmet gecko is a series of distinct concentric zones of different refractive powers, as per a research studyreported in the Association for Research in Vision and Ophthalmology's peer-evaluated, online Journal of Vision ("The pupils and optical systems of gecko eyes," http://www.journalofvision.org/9/3/27).

This multifocal optical system is comprised of large cones, which the scientists calculated to be more than 350 times more sensitive than human cone vision at the human color vision threshold.

"We were interested in the geckos because they and other lizards differ from most other vertebrates in having only cones in their retina," said project leader Lina Roth, PhD, from the Department of Cell and Organism Biology at Lund University in Sweden. "With the knowledge from the gecko eyes we might be able to develop more effective cameras and maybe even useful multifocal contact lenses".

The nocturnal geckos' multifocal optical system gives them an advantage because light of different ranges of wavelengths can focus simultaneously on the retina. Another possible advantage of their optical structure is that their eyes allow them to focus on objects at different distances. Therefore the multifocal eye would generate a sharp image for at least two different depths. Geckos that are active during the day do not possess the distinct concentric zones and are considered monofocal, Roth said......... Posted by: Kelly      Read more         Source

May 1, 2009, 5:27 AM CT

Wildlife Trade And Ecosystems

Wildlife imports into the United States are fragmented and insufficiently coordinated, failing to accurately list more than four in five species entering the country.

So reports a team of researchers from the Wildlife Trust, Brown University, Pacific Lutheran University, the Centers for Disease Control and Prevention, and the Global Invasive Species Programme.

A paper on their findings is published in this week's issue of the journal Science.

The poorly regulated U.S. wildlife trade can lead to devastating effects on ecosystems, native species, food supply chains and human health.

"As our world, in a number of senses, grows smaller and smaller with the ease of international travel, the network of connections has increased, facilitating the spread of diseases," said Rita Teutonico, senior advisor for integrative activities in the National Science Foundation's (NSF) Directorate for Social, Behavioral & Economic Sciences (SBE).

SBE co-funded this research through the agency's Human and Social Dynamics (HSD) priority area. HSD was supported by all NSF Directorates, and by NSF's Office of International Science and Engineering and Office of Polar Programs.

"These researchers report a pattern of trade in wildlife that includes a very large number of animals, coupled with a poor understanding of what species are traded," said James Collins, NSF Assistant Director for Biological Sciences. "The findings highlight the need for further research because of the unknown effects these animals and their pathogens can have on native organisms"......... Posted by: Kelly      Read more         Source

May 1, 2009, 5:11 AM CT

Dolphins maintain round-the-clock visual vigilance

Dolphins have a clever trick for overcoming sleep deprivation. Sam Ridgway from the US Navy Marine Mammal Program explains that they are able to send half of their brains to sleep while the other half remains conscious. What is more, the mammals seem to be able to remain continually vigilant for sounds for days on end. All of this made Ridgway and colleagues from San Diego and Tel Aviv wonder whether the dolphins' unrelenting auditory vigilance tired them and took a toll on the animals' other senses? Ridgway and his team set about testing two dolphins' acoustic and visual vigilance over a 5 day period to find out how well they functioned after days without a break. The team publish their results on May 1 2009 in the Journal of Experimental Biology at http://jeb.biologists.org.

First Ridgway and colleagues, Mandy Keogh, Mark Todd and Tricia Kamolnick, trained two dolphins to respond to a 1.5 s beep sounded randomly against a background of 0.5 s beeps every 30 s. Ridgway explains that the sounds were low enough for the dolphins to barely notice them as they swam through their enclosure, but the animals sprung into action every time they heard the 1.5 s tone, even after listening to the sounds for 5 days without a break. Their auditory vigilance remained as sharp as it had been 5 days earlier......... Posted by: Kelly      Read more         Source

April 30, 2009, 9:35 PM CT

Fish may feel pain and react like humans

Fish don't make noises or contort their faces to show that it hurts when hooks are pulled from their mouths, but a Purdue University researcher believes they feel that pain all the same.

Joseph Garner, an assistant professor of animal sciences, helped develop a test that found goldfish do feel pain, and their reactions to it are much like that of humans. A paper detailing the finding was reported in the early online version of the journal Applied Animal Behaviour Science.

"There has been an effort by some to argue that a fish's response to a noxious stimuli is merely a reflexive action, but that it didn't really feel pain," Garner said. "We wanted to see if fish responded to potentially painful stimuli in a reflexive way or a more clever way".

Garner and Janicke Nordgreen, a doctoral student in the Norwegian School of Veterinary Science, attached small foil heaters to the goldfish and slowly increased the temperature. The heaters were designed with sensors and safeguards that shut off the heaters to prevent any physical damage to a fish's tissue.

Half of the fish were injected with morphine, and the others received saline. The scientists believed that those with the morphine would be able to withstand higher temperatures before reacting if they actually felt the pain. However, both groups of fish showed a response at about the same temperature......... Posted by: Kelly      Read more         Source

April 24, 2009, 5:03 AM CT

US shorts critical farm animal research

Dwindling federal funding jeopardizes important animal and biomedical research, together with the institutional research programs that focus on them, a group of Michigan State University researchers warn.

The alarm was sounded today in the journal Science by MSU scientists James Ireland, George Smith, Jose Cibelli and five colleagues from other institutions. It comes just as the landmark sequencing of the domestic cattle genome is published in the same issue.

Only $32 million of the $88 billion 2007 U.S. Department of Agriculture budget went toward competitive farm animal research grants, the group wrote. The proportion of the National Institutes of Health budget for extramural support of human health research is more than 900 times larger, they said, while U.S. livestock and poultry sales exceed $132 billion annually.

Animal science programs are withering at American institutions as a consequence, they warned. Not only are certain farm animal species themselves facing threats -- poultry in particular face loss of breed genetic diversity but human health studies might also suffer from lack of funding for large-animal research.

Seventeen Nobel laureates have used farm animals as research models, they wrote, and new information on animal genetics such as the bovine genome sequence reported today promise new insights into gene function as well as genetic and environmental influences on animal production and human disease......... Posted by: Kelly      Read more         Source

April 22, 2009, 10:11 PM CT

Plants could override climate change effects on wildfires

Researchers predict that global climate change will make a number of regions around the world warmer and drier, a factor which, taken by itself, would seem to increase the risk of wildfires.

But a newly released study led by a Montana State University researcher shows that changes in the types of vegetation covering an area play a major role in determining how often that area is burned by fires and could even counteract the effects of changes in temperature and moisture.

In the study, MSU earth sciences post-doctoral researcher Philip Higuera and colleagues show that the risk of wildfires can be either reduced or increased by changes in the distribution and abundance of plants. The study would be reported in the recent issue of the journal Ecological Monographs.

"Climate affects vegetation, vegetation affects fire and both fire and vegetation respond to climate change," Higuera said. "Our work emphasizes the need to consider the multiple drivers of fire regimes when we anticipate how they will respond to climate change."

Higuera and colleagues studied fire history in northern Alaska by analyzing sediments at the bottom of lakes, some dating as far back as 15,000 years. In the samples from the lakes, the researchers measured the abundance of different preserved plant parts, such as pollen, to determine what types of vegetation dominated the region in the past. Like rings in a tree, different sediment layers represent different times in the past......... Posted by: Erica      Read more         Source

April 22, 2009, 5:17 AM CT

How genes are controlled in mammals

Researchers at the Omics Science Center (OSC) of the RIKEN Yokohama Institute in Japan along with scientists from McGill University and other institutions worldwide are challenging current notions of how genes are controlled in mammals. Three years of intensive research by members of the international FANTOM consortium will culminate with the publication of several milestone scientific papers in Nature Genetics and other journals on April 20.

FANTOM4, the fourth stage of the Functional Annotation of the Mammalian cDNA collaboration, is led by Dr. Yoshihide Hayashizaki of OSC. Dr. Jose Dostie, a biochemist at McGill's Faculty of Medicine joined the FANTOM4 collaboration in 2007 and is its only Canadian member.

For several years, FANTOM scientists have provided the scientific community with extensive data on the genome of mammals, including detailed information on molecular function, biology and individual cell components. Now, the FANTOM4 stage of the collaboration has culminated in a breakthrough that will alter the way researchers understand transcription, the process of cellular copying and reproduction.

"This study really challenges the way we understand cellular differentiation," explained Dr. Dostie, who participated in the primary FANTOM4 research and also authored a satellite paper for publication in the journal Genome Biology. "The dogma right now is that there are so-called 'master regulators,' a series of protein switches that sit in specific places on the genome and induce genes. This is supposed to lead to a cascade that leads to cellular differentiation......... Posted by: Kelly      Read more         Source

April 21, 2009, 5:20 AM CT

Lizards bask for more than warmth

Keeping warm isn't the only reason lizards and other cold-blooded critters bask in the sun. As per a research studyreported in the May/recent issue of Physiological and Biochemical Zoology, chameleons alter their sunbathing behavior based on their need for vitamin D.

"It's a longstanding assumption that thermoregulation is the only reason that lizards bask," says Kristopher Karsten, a biologist at Texas Christian University who led the study. "Our results suggest that in addition to thermoregulation, vitamin D regulation appears to have a significant impact on basking behavior as well".

Chameleons, like humans and most other vertebrates, get vitamin D in two ways: They can absorb it from food, and they can produce it in their skin. In order to produce vitamin D, however, the skin must be exposed to UV radiation.

To test whether chameleons alter their sunning behavior based on dietary vitamin D intake, Karsten observed the behavior of two different groups of chameleons. One group had high internal vitamin D levels, thanks to a diet of crickets dusted with a vitamin D powder. The other group ate regular crickets and had low vitamin D. The chameleons were then placed in individual outdoor enclosures that offered open area for direct sun, and a tree to offer filtered sun and shade......... Posted by: Kelly      Read more         Source

April 21, 2009, 5:19 AM CT

How cells change gears

Bioinformatics scientists from UC San Diego just moved closer to unlocking the mystery of how human cells switch from "proliferation mode" to "specialization mode." This computational biology work from the Jacobs School of Engineering's bioengineering department could lead to new ideas for curbing unwanted cell proliferationincluding some cancers. This research, published in Nature Genetics, could also improve our understanding of how organs and other complex tissues develop.

The UC San Diego bioengineers are part of a Japan-based global research consortium, the Genome Network Project, which generated one of the first close-to-comprehensive looks at a human cell's entire network of proteins called "transcription factors." Each human cell contains approximately 2,000 transcription factors, which are proteins that bind to specific locations on the cell's DNA. Once bound to DNA, transcription factors work to either encourage or prevent "transcription"the process by which messenger RNA is generated from DNA. These messenger RNA strands then travel to cellular factories called ribosomes which churn out proteins based on the specifications of the mRNA.

"Transcription is one of the most important events in the cellit determines cell morphology and cell function," said Timothy Ravasi, a UC San Diego research scientist from the bioengineering department and author on the new Nature Genetics paper......... Posted by: Janet      Read more         Source

April 20, 2009, 9:54 PM CT

Nitrogen-fixing bacteria protect soybeans

An invasion of soybean aphids poses a problem for soybean farmers requiring application of pesticides, but a team of Penn State entomologists thinks a careful choice of nitrogen-fixing bacteria may provide protection against the sucking insects.

Soybeans are legumes, plants that can have a symbiotic relationship with nitrogen-fixing bacteria - rhizobia - and therefore do not need additional nitrogen fertilizer. Each type of legume - peas, beans, lentils, alfalfa - have their own rhizobia.

"Soybeans are from Asia and so there were originally no nitrogen-fixing bacteria that would colonize soybeans in U.S. soils," said Consuelo De Moraes, associate professor of entomology. "The rhizobia had to be transferred here".

The soybean aphid is also not native to North America. This pest only began to infest soybean fields about 10 years ago but are now fully established pests requiring pesticide applications to avoid the loss of as much as 40 percent of the crop. The scientists investigated the relationship between the type of rhizobia colonizing soybean plants and the plants' infestation with the aphids.

"Our results demonstrate that plant-rhizobia interactions influence plant resistance to insect herbivores and that some rhizobia strains confer greater resistance to their mutualist partners than do others," the scientists report in the journal Plant and Soil online......... Posted by: Janet      Read more         Source

April 20, 2009, 9:42 PM CT

New Chemical Reaction for DNA Production

A team of scientists has discovered a new chemical reaction for producing one of the four nucleotides, or building blocks, needed to build DNA. The reaction includes an unusual first step, or mechanism, and unlike other known reactions that produce the DNA building block, uses an enzyme that speeds up, or catalyzes, the reaction without bonding to any of the compounds, or substrates, in the reaction.

The chemical reaction discovered by the scientists uses an enzyme called flavin-dependent thymidylate synthase, or FDTS. The enzyme is coded by the thyX gene and has been found primarily in bacteria and viruses, including several human pathogens and biological warfare agents. In the future, researchers may use this knowledge for the development of new antibacterial and antiviral drugs.

Supported with partial funding from the National Science Foundation (NSF) and led by Amnon Kohen, an associate professor in the departments of chemistry and molecular and cellular biology at the University of Iowa, the team reports their findings in the April 16, 2009, issue of Nature, Letters section.

Previous to the team's discovery, it was thought that thymidylate synthase, or TS, was the primary enzyme catalyzing a reaction that produced one of the four DNA building blocks called deoxy-thymidine monophosphate......... Posted by: Janet      Read more         Source

April 20, 2009, 9:37 PM CT

Unusual Antarctic Microbes Lived in Extreme Conditions

An unmapped reservoir of briny liquid chemically similar to sea water, but buried under an inland Antarctic glacier, appears to support unusual microbial life in a place where cold, darkness and lack of oxygen would previously have led researchers to believe nothing could survive, as per newly published research.

After sampling and analyzing the outflow from below the Taylor Glacier, an outlet glacier of the East Antarctic Ice Sheet in the otherwise ice-free McMurdo Dry Valleys of Antarctica, scientists think that, lacking enough light to make food through photosynthesis, the microbes have adapted over the past 1.5 million years to manipulate sulfur and iron compounds to survive.

The microbes also are remarkably similar in nature to species found in marine environments, leading to the conclusion that the populations under the glacier are the remnants of a larger population of microbes that once occupied a fjord or sea that received sunlight. A number of of these marine lineages likely declined, while others adapted to the changing conditions when the Taylor Glacier advanced, sealing off the system under a thick ice cap.

The research would be reported in the April 17 edition of the journal Science.

The research answers some questions and raises others about the persistence of life in extreme environments such as under glaciers, or even in liquid lakes trapped kilometers under the Antarctic ice sheet, environments that until recently researchers would not have believed could support living creatures......... Posted by: Janet      Read more         Source

April 20, 2009, 5:15 AM CT

Antioxidant benefits of tart cherries

Eating just one and a half servings of tart cherries could significantly boost antioxidant activity in the body, according to new University of Michigan research reported at the 2009 Experimental Biology meeting in New Orleans.¹ In the study, healthy adults who ate a cup and a half of frozen cherries had increased levels of antioxidants, specifically five different anthocyanins the natural antioxidants that give cherries their red color.

Twelve healthy adults, aged 18 to 25 years, were randomly assigned to eat either one and a half cups or three cups of frozen tart cherries. Researchers analyzed participants' blood and urine at regular intervals after they ate the cherries and found increased antioxidant activity for up to 12 hours after eating cherries.

"This study documents for the first time that the antioxidants in tart cherries do make it into the human bloodstream and is coupled with increased antioxidant activity that could have a positive impact," said Sara L. Warber, MD, Co-Director of University of Michigan Integrative Medicine and principal investigator of the study. "And, while more research is needed, what's really great is that a reasonable amount of cherries could potentially deliver benefits, like reducing risk factors for heart disease and inflammation." ......... Posted by: Erica      Read more         Source

April 17, 2009, 5:22 AM CT

Museum specimens aid conservation efforts

There is a new tool for those developing conservation strategies for threatened species and landscapes: museum specimens. Richard Pearson and Christopher Raxworthy of the American Museum of Natural History dusted off many collections from Madagascar and used the location information linked to each species to test different ideas regarding the evolution of locally distributed endemism (unique species confined to small regions). The research paper published this month in Evolution found support for alternative hypotheses, suggesting that multiple processes develop local endemism. This improved knowledge of the processes that lead to endemism can help to identify priorities in conservation planning.

"Museum records can be used for conservation purposes, particularly because they tie together generations of data," says Pearson, a Biodiversity Scientist at the Museum's Center for Biodiversity and Conservation. "Madagascar is a unique natural laboratory for this project because of the large amount of local endemism and because the government's decision to set aside land has spurred an effort to prioritize the location of reserves within the landscape".

Madagascar is an island nation in the Indian Ocean that has been completely isolated from other land masses for the last 80 million years. Isolation has led to a high number of unique species like chameleons (Furcifer petteri), lemurs (Lemur catta), and day geckos (Phelsuma madagascariensis) which, in turn, has led Madagascar to be labeled a biodiversity "hotspot" by conservation groups. The Malagasy government pledged to set aside 10 percent of the land for conservation purposes as part of the 2003 World Parks Congress in Durban. Prior research papers have attempted to use species location records to determine which areas of the island would conserve the largest number of species......... Posted by: Kelly      Read more         Source

April 17, 2009, 5:20 AM CT

Size and suitability as a mate

A new study by scientists at the University of Alaska Fairbanks offers evidence that in one breed of northern seabird, the size of males' feather crests appears to be more than simple ornamentation.

Their study, published this month in of the Journal of Comparative Physiology B, shows that crest size appears to be a physical indicator of a male crested auklet's quality as a mate.

Researchers have long noted that female auklets prefer males with larger crests. But until recently, they did not know why. Low levels of stress hormones in males with larger crests indicate that they cope better with the stresses of reproduction, such as finding food, competing with thousands of other birds for mates and nest sites, and helping rear chicks.

"Females will divorce shorter-crested mates for the opportunity to mate with longer-crested males. Our study suggests that longer-crested males could contribute more to reproductive success because they have greater capacity to meet the social and physiological costs," said Hector Douglas, assistant professor of biology at the Kuskokwim Campus in Bethel.

Douglas and collaborator Alexander Kitaysky, an associate professor at the UAF Institute of Arctic Biology, say their results fit into a larger theory about animal societies......... Posted by: Kelly      Read more         Source

April 17, 2009, 5:17 AM CT

What life may have been like for dinosaurs?

During the last 540 million years, the earth's oxygen levels have fluctuated wildly. Knowing that the dinosaurs appeared around the time when oxygen levels were at their lowest at 12%, Tomasz Owerkowicz, Ruth Elsey and James Hicks wondered how these monsters coped at such low oxygen levels. But without a ready supply of dinosaurs to test their ideas on, Owerkowicz and Hicks turned to a modern relative: the alligator. 'We knew testing the effects of different oxygen levels would work with alligators,' Owerkowicz explains, 'because crocodilians have survived in their basic shape and form for 220 million years. They must be doing something right to have survived the oxygen fluctuations.' Choosing to start at the beginning of alligator development, the trio decided to try incubating alligator eggs at different oxygen levels, to find out how the youngsters grew and developed and publish their results on April 17 2009 in The Journal of Experimental Biology at http://jeb.biologists.org.

Receiving newly laid alligator eggs from Elsey at the Rockefeller Wildlife Refuge, Owerkowicz divided the eggs into groups incubated at 12% (low) oxygen, 21% (normal) oxygen and 30% (high) oxygen, and waited to see what would happen. After almost 10 weeks of waiting, the eggs began hatching and Owerkowicz could see that there were no obvious differences between the alligators that developed in normal and high oxygen atmospheres......... Posted by: Kelly      Read more         Source

April 16, 2009, 5:26 AM CT

Red pandas and sweet tooth

PHILADELPHIA (April 15, 2009) -- Scientists from the Monell Center report that the red panda is the first non-primate mammal to display a liking for the artificial sweetener aspartame. This unexpected affinity for an artificial sweetener may reflect structural variation in the red panda's sweet taste receptor.

The findings may shed light on how taste preferences and diet choice are shaped by molecular differences in taste receptors.

"The red panda's unique taste receptor gives us a tool to broaden our understanding of how we detect sweet taste," said the paper's senior author, Joseph G. Brand, PhD, a biophysicist at Monell. "Greater insight into why we like artificial sweeteners could eventually lead to the development of more acceptable sugar substitutes, potentially benefiting diabetics and other individuals on sugar-restricted diets".

A number of species like sweet-tasting foods, but there are some exceptions. In an earlier study, Brand and Monell comparative geneticist Xia Li, PhD, reported that cats both domestic and wild can not taste sweets due to a defect in one of the genes that codes for the sweet taste receptor.

The current research extended those findings by relating sweet preferences to genetic analyses of sweet receptor structure in six related species. Like the cat, each of the species tested -- red panda, ferret, genet, meerkat, mongoose, and lion -- belongs to the Order Carnivora......... Posted by: Kelly      Read more         Source

April 16, 2009, 5:23 AM CT

Researcher names lichen after President Obama

A researcher at UC Riverside has discovered a new species of lichen a plant-like growth that looks like moss or a dry leaf and named it after President Barack Obama.

"I discovered the new species in 2007 while doing a survey for lichen diversity on Santa Rosa Island in California," said Kerry Knudsen, the lichen curator in the UCR Herbarium. "I named it Caloplaca obamae to show my appreciation for the president's support of science and science education".

Knudsen published his discovery in the recent issue of the journal Opuscula Philolichenum

"I made the final collections of C. obamae during the suspenseful final weeks of President Obama's campaign for the United States presidency, and this paper was written during the international jubilation over his election," Knudsen said. "Indeed, the final draft was completed on the very day of President Obama's inauguration".

C. obamae, the first species of any organism to be named in honor of President Obama, grows on soil and almost became extinct during the days of cattle ranching that spanned nearly a hundred years on Santa Rosa Island.

"This species barely survived the intensive grazing of cattle, elk and deer on Santa Rosa Island," Knudsen said. "But with cattle now removed, it has begun to recover. With future removal of elk and deer both of which were introduced to the island it is expected to fully recover"......... Posted by: Janet      Read more         Source