April 26, 2010, 7:27 PM CT

New monitor lizard discovered

A newly discovered species of monitor lizard, a close relative of the Komodo dragon, was published in the journal Zootaxa this week by a professor at UC Santa Barbara and a researcher from Finland.

Sam Sweet, a professor in the department of Ecology, Evolution and Marine Biology at UCSB, and Valter Weijola, a graduate student at Abo Akademi University in Turku, Finland, are the first to describe the distinctive lizard, which lives in the Moluccan islands of east Indonesia. Sweet is an authority on monitor lizard biology.

The scientific name of this lizard is Varanus obor; its popular names are Torch monitor and Sago monitor. It's called Torch monitor because of its bright orange head with a glossy black body. Obor means torch in Indonesian. It is a close relative of the fruit-eating monitor lizard recently reported from the Philippines. The Torch monitor can grow to nearly four feet in length, and thrives on a diet of small animals and carrion.

The Torch monitor exists only on the small island of Sanana in the western Moluccan islands. A unique aspect of this geographical region is the lack of mammalian predators, which may have given reptiles the space to evolve as the top terrestrial predators and scavengers. Several million years ago, this island was situated near New Guinea, and it is possible that the lizard lives on as a relic from that period. It is the only black monitor in its lineage, and the only monitor species anywhere that has evolved red pigmentation......... Posted by: Kelly      Read more         Source

April 25, 2010, 1:43 PM CT

Multiple defenses act synergistically in aspen

If plants did not defend themselves in some way, they would certainly be gobbled up by a whole suite of voracious predators ranging from little insects to large mammalian herbivores. Indeed, not only do plants defend themselves, they typically have more than one kind of defense. When a plant has several options, how does it choose? Does it allocate multiple defenses to the same tissues or defend different tissues in different ways?

Diane Wagner and his colleagues from the University of Alaska, Fairbanks, examined how two defensesphenolic glycosides (a direct chemical defense) and extrafloral nectaries (an indirect defense) were distributed among leaves of a plant in the trembling aspen (Populus tremuloides) in Alaska. They found unique findings contradicting all expectations and published them in the recent issue of the American Journal of Botany (http://www.amjbot.org/cgi/content/full/97/4/601).

Diane Wagner has had a long-standing interest in extrafloral nectaries, or EFNs, which in general serve as an indirect plant defense. EFNs are found on the petiole at the base of a leaf and serve to attract insect predators who consume both the nectar produced by the plant and herbivorous insects that attack the plant.

"After noticing EFNs on aspen leaves about 7 years ago, I was surprised to find that very few biologists had studied their function in aspen," Wagner noted. Trembling aspen is common and widespread in North America and is a species of considerable aesthetic and ecological importance. So Wagner joined forces with Pat Doak, an insect population ecologist, to look at the functional significance of EFNs in trembling aspen. The study was funded by the National Science Foundation......... Posted by: Erica      Read more         Source

April 25, 2010, 1:39 PM CT

Worm genes KO'd

Knocking genes out of action allows scientists to learn what genes do by seeing what goes wrong without them. University of Utah biologists pioneered the field. Mario Capecchi won a Nobel Prize for developing knockout mice. Kent Golic found a way to cripple fruit fly genes. Now, biologist Erik Jorgensen and his colleagues have devised a procedure for knocking out genes in nematode worms.

"We developed a method that allows us to walk through the worm genome and determine the function of each gene, and thereby infer the function of these genes in humans," says Jorgensen, a biology professor, senior author of a newly released study outlining the technique, and an investigator with the Howard Hughes Medical Institute.

The study shows how a transposon or "jumping gene" can be used to delete specific genes from the 1-millimeter-long nematode worm, Caenorhabditis elegans. It was scheduled for online publication Sunday, April 25 in the journal Nature Methods

"We are trying to understand how genes work and are regulated, and the easiest way to do that is to use a simple organism," says University of Utah postdoctoral fellow Christian Frkjr-Jensen, the study's first author. "The amazing thing is that cellular processes in a lowly worm are similar to the biology in humans. We've made it much easier and faster to change the genetic blueprint of a simple worm so we can study and understand how genes are regulated"......... Posted by: Janet      Read more         Source

April 24, 2010, 9:36 AM CT

Ten Most Wanted Plants

Students, gardeners, retirees and other volunteers across the nation who are taking part in a nationwide initiative--Project BudBurst--are finding hints that certain plants are blooming uncommonly early, perhaps as a result of climate change.

The citizen researchers are recording the timing of flowers and foliage, amassing thousands of observations from across the nation to give scientists a detailed picture of our changing climate.

The project, which started as a pilot program in 2007, now focuses on a list of the "10 most wanted species"--flowers and trees such as the common lilac, red maple and Virginia bluebell.

Such widely distributed plants can provide important early signs of the impact of warming temperatures on the environment, as per the researchers who designed the project.

"Project BudBurst empowers people living anywhere in the country to make a contribution that will lead to better understanding of our environment," said Project BudBurst director Sandra Henderson of the University Corporation for Atmospheric Research (UCAR) Office of Education and Outreach. "This is needed data to help researchers who are studying the impacts of climate change".

Project BudBurst is operated by UCAR and the Chicago Botanic Garden, and is a partner in the USA National Phenology Network......... Posted by: Erica      Read more         Source

March 24, 2010, 10:27 AM CT

Petri Sheep

In the winter of 2003, a large herd of bison in an Idaho feedlot was cut in half when a disease outbreak swept through, killing 825 animals.

Two years ago, 19 cattle, most owned by FFA students, died after being shown in Washington's Puyallup State Fair.

In both instances, Washington State University scientists determined the animals died of cancerous catarrhal fever because they had been kept near flocks of sheep, which routinely carry a disease called ovine herpes virus 2. Scientists have known of the disease for decades, but have repeatedly been frustrated in their attempts to grow it in a lab-a major step in developing a vaccine.

So they use the next best thing to a Petri dish: sheep.

USDA and WSU researchers, writing in an upcoming issue of the journal Veterinary Microbiology, say they have propagated the virus in sheep and for the first time identified specific cells where it can replicate. Their discovery opens the door for growing these cells and the virus in a laboratory setting, where they can then begin developing vaccines.

Naomi Taus, main author and veterinary medical officer for the Pullman unit of the USDA's Agricultural Research Service, says she and her colleagues collected secretions from sheep-snot, actually-and aerosolized it to expose other sheep. They then took tissue samples from the sheep and searched for infections by looking for fluorescent markers designed to bind with proteins linked to the virus and certain cell types......... Posted by: Kelly      Read more         Source

March 19, 2010, 10:50 AM CT

Mexican Cave Scorpions

Blind scorpions that live in the stygian depths of caves are throwing light on a long-held assumption, showing that specialized adaptations aren't always an evolutionary dead-end. Looking at the phylogenetic relationships among species of the scorpion family Typhlochactidae, endemic to Mexico, Associate Curator Lorenzo Prendini and his colleagues observed that species currently living closer to the surface (under stones and in leaf litter) evolved independently on more than one occasion from specialized deep-cave ancestors adapted to life further below the surface (in caves). This finding puts a dent in both Cope's Law of the unspecialized, which assumes that novel evolutionary traits tend to originate from a generalized member of an ancestral taxon, and Dollo's Law of evolutionary irreversibility, which theorizes that specialized evolutionary traits are unlikely to reverse.

Scorpions are predatory, venomous, nocturnal arachnids correlation to spiders, mites, and other arthropods. About 2,000 species are distributed throughout the world, but only 23 species found in ten different families are adapted to a permanent life in caves. One of these families is the Typhlochactidae, comprising four genera and nine species.

"Scorpions have been around for 450 million years, and their biology is obviously flexible," says Prendini. "This unique group of eyeless Mexican scorpions may have started re-colonizing niches closer to the surface from the deep caves of Mexico after their surface-living ancestors were wiped out by the nearby Chicxuluxb impact along with non-avian dinosaurs, ammonites, and other species"......... Posted by: Kelly      Read more         Source

March 19, 2010, 10:48 AM CT

Dogs likely originated in the Middle East

Dogs likely originated in the Middle East, not Asia or Europe, as per a new genetic analysis by an international team of researchers led by UCLA biologists. The research, funded by the National Science Foundation and the Searle Scholars Program, appears March 17 in the advance online edition of the journal Nature.

"Dogs seem to share more genetic similarity with Middle Eastern gray wolves than with any other wolf population worldwide," said Robert Wayne, UCLA professor of ecology and evolutionary biology and senior author of the Nature paper. "Genome-wide analysis now directly suggests a Middle East origin for modern dogs. We have observed that a dominant proportion of modern dogs' ancestry derives from Middle Eastern wolves, and this finding is consistent with the hypothesis that dogs originated in the Middle East.

"This is the same area where domestic cats and a number of of our livestock originated and where agriculture first developed," Wayne noted.

Prior genetic research suggested an East Asian origin for dogs, "which was unexpected," Wayne said, "because there was never a hint in the archaeological record that dogs evolved there".

"We were able to study a broader sampling of wolves globally than has ever been done before, including Middle Eastern wolves," said the paper's main author, Bridgett vonHoldt, a UCLA graduate student of ecology and evolutionary biology in Wayne's laboratory who studies the genetics of dog domestication. "In our analysis of the entire genome, we observed that dogs share more unique markers with Middle Eastern wolves than with East Asian wolves. We used a genome-wide approach, which avoids the bias of single genome region"......... Posted by: Kelly      Read more         Source

March 17, 2010, 8:17 PM CT

Spider silk reveals a paradox

Since its development in China thousands of years ago, silk from silkworms, spiders and other insects has been used for high-end, luxury fabrics as well as for parachutes and medical sutures. Now, National Science Foundation-supported scientists are untangling some of its most closely guarded secrets, and explaining why silk is so super strong.

Scientists at the Massachusetts Institute of Technology's Center for Materials Science and Engineering say the key to silk's pound-for-pound toughness, which exceeds that of steel, is its beta-sheet crystals, the nano-sized cross-linking domains that hold the material together.

Markus Buehler, the Esther and Harold E. Edgerton Associate Professor in MIT's department of civil and environmental engineering, and his team recently used computer models to simulate exactly how the components of beta sheet crystals move and interact with each other. They observed that an unusual arrangement of hydrogen bonds--the "glue" that stabilizes the beta-sheet crystals--play an important role in defining the strength of silk.

They observed that hydrogen bonds, which are among the weakest types of chemical bonds, gain strength when confined to spaces on the order of a few nanometers in size. Once in close proximity, the hydrogen bonds work together and become extremely strong. Moreover, if a hydrogen bond breaks, there are still a number of hydrogen bonds left that can contribute to the material's overall strength, due to their ability to "self-heal" the beta-sheet crystals......... Posted by: Kelly      Read more         Source

March 15, 2010, 8:06 PM CT

3-D cell culture

The film "Avatar" isn't the only 3-D blockbuster making a splash this winter. A team of researchers from Houston's Texas Medical Center this week unveiled a new technique for growing 3-D cell cultures, a technological leap from the flat petri dish that could save millions of dollars in drug-testing costs. The research is reported in Nature Nanotechnology

The 3-D technique is easy enough for most labs to set up immediately. It uses magnetic forces to levitate cells while they divide and grow. Compared with cell cultures grown on flat surfaces, the 3-D cell cultures tend to form tissues that more closely resemble those inside the body.

"There's a big push right now to find ways to grow cells in 3-D because the body is 3-D, and cultures that more closely resemble native tissue are expected to provide better results for preclinical drug tests," said co-author of study Tom Killian, associate professor of physics at Rice. "If you could improve the accuracy of early drug screenings by just 10 percent, it's estimated you could save as much as $100 million per drug".

For cancer research, the "invisible scaffold" created by the magnetic field goes beyond its potential for producing cell cultures that are more reminiscent of real tumors, which itself would be an important advance, said co-author Wadih Arap, professor in the David H. Koch Center at The University of Texas M.D. Anderson Cancer Center......... Posted by: Janet      Read more         Source

March 15, 2010, 7:57 PM CT

How sea lilies got their get-up-and-go

Nature abounds with examples of evolutionary arms races. Certain marine snails, for example, evolved thick shells and spines to avoid be eaten, but crabs and fish foiled the snails by developing shell-crushing claws and jaws.

Common as such interactions appears to be, it's often difficult to trace their origins back in evolutionary time.

Now, a study by University of Michigan paleontologist Tomasz Baumiller and his colleagues finds that sea urchins have been preying on marine animals known as crinoids for more than 200 million years and suggests that such interactions drove one type of crinoid---the sea lily---to develop the ability to escape by creeping along the ocean floor. The work, which builds on prior research on present-day sea lilies and urchins, is scheduled to be published online this week in the Proceedings of the National Academy of Sciences

With their long stalks and feathery arms, sea lilies look a lot like their garden-variety namesakes. Perhaps because of that resemblance, researchers long had thought that sea lilies stayed rooted instead of moving around like their stalkless relatives, the feather stars. But in the 1980s, Baumiller and collaborator Charles Messing of Nova Southeastern University's Oceanographic Center in Dania Beach, Fla., observed sea lilies shedding the ends of their stalks to release themselves from their anchor points and using their feathery arms to crawl away, dragging their stalks behind them......... Posted by: Janet      Read more         Source