March 27, 2008, 9:28 PM CT

Small desert beetle found to engineer ecosystems

The mesquite girdler Oncideres rhodosticta may only be 13mm long, but it has a big role in shaping the landscape. Research carried out by Benjamin Duval and Walter Whitford at New Mexico State University has revealed that the beetle is speeding up the degradation of grasslands in the Chihuahua desert, the landscape so stunningly depicted in this years Oscar-winning film No Country for Old Men.

The mesquite girdler does this by regulating the growth of the mesquite shrub, ensuring their offspring have a plentiful supply of food. The beetles chew girdles around the older stems of the shrub, which forces the plant to regrow new stems the following year. The new stems supply the beetle larvae with food, but the mesquite shrub takes more nutrients from the soil for its increased growth, leaving less for the other plant species such as grasses.

Up to 150 years ago, the North Chihuahuan Desert was completely covered in grassland. The picture today is very different dunes and mesquite shrubs cover much of the landscape.

Duval said: Eventhough the desertification process was likely started by overgrazing cattle, the ecosystem engineering impact of the mesquite girdler could finish off the process......... Posted by: Kelly      Read more         Source

March 27, 2008, 9:21 PM CT

Can you rescue a rainforest?

Half a century after most of Costa Rica's rainforests were cut down, scientists from the Boyce Thompson Institute took on a project that a number of thought was impossible - restoring a tropical rainforest ecosystem.

When the scientists planted worn-out cattle fields in Costa Rica with a sampling of local trees, native species began to move in and flourish, raising the hope that destroyed rainforests can one day be replaced.

Carl Leopold and his partners in the Tropical Forestry Initiative began planting trees on worn-out pasture land in Costa Rica in 1992. For 50 years the soil was compacted under countless hooves, and its nutrients washed away. When it rained, Leopold says, red soil appeared to bleed from the hillsides.

The group chose local rainforest trees, collecting seeds from native trees in the community. "You can't buy seeds," Leopold says. "So we passed the word around among the neighbors." When a farmer would notice a tree producing seeds, Leopold and his wife would ride out on horses to find the tree before hungry monkeys beat them to it.

The group planted mixtures of local species, trimming away the pasture grasses until the trees could take care of themselves. This was the opposite of what commercial companies have done for decades, planting entire fields of a single type of tree to harvest for wood or paper pulp......... Posted by: Erica      Read more         Source

March 27, 2008, 9:11 PM CT

'Wildcat Power Cord' repairs cruciate ligament

An 8-year-old Jersey dairy cow is back at her Kansas farm thanks to a decade of research and an experimental surgery performed at Kansas State University's Veterinary Medical Teaching Hospital.

The cow, named Wilhelmina Jolene by the veterinary students assigned to her case, sustained a breeding injury in December 2007 when the cruciate ligament in her right knee ruptured. Dr. David Anderson, professor and head of agricultural practices at K-State's College of Veterinary Medicine, replaced the ligament using synthetic material called monofilament nylon. The procedure's success could have enormous implications for breeding quality cows and bulls with the same injury.

Fortunately, Wilhelmina's owner recognized the value of saving her. Mike Frey is the son of Dr. Russ Frey, a prominent professor at K-State's College of Veterinary Medicine. "She's owned by the son of an important faculty member in our college's history," Anderson said. "It's wonderful that there is a connection to Dr. Frey with this case and that Mike understands the teaching value."

Mike Frey said he was happy to be part of an effort that could help animals, producers and students.

"I was always under the assumption that an animal with this problem was going to be heading down the road," he said. "If they could perfect this so that a cow could be kept in production, that would be worth quite a bit"......... Posted by: Kelly      Read more         Source

March 25, 2008, 7:57 PM CT

Pepper Spray For Deterring Bears

Hikers and campers venturing into bear country this spring may be safer armed with 8-ounce cans of bear pepper spray than with guns, as per a new study led by a Brigham Young University bear biologist.

Thomas S. Smith, associate professor of wildlife science, has conducted field work among bears for 16 years and has never used bear spray, eventhough he carries it faithfully. "I wish I had more scary stories to share, but I've behaved myself," said Smith, emphasizing that caution and wisdom are the best way to prevent bear attacks.

Concerned about hikers' and campers' persistent doubts that a small can of liquid pepper spray could stop half a ton of claws, muscle and teeth, Smith and his colleagues analyzed 20 years of bear spray incidents in Alaska, home to 150,000 bears. He observed that the spray effectively halted aggressive bear behavior in 92 percent of the cases, whether that behavior was an attack or merely rummaging for food. Of all 175 people involved in the incidents studied, only three were injured by bears, and none mandatory hospitalization. Smith and his research team report their findings in the recent issue of the Journal of Wildlife Management.

"People working or recreating in bear habitat should feel confident they are safe if carrying bear spray," Smith said......... Posted by: Kelly      Read more         Source

March 24, 2008, 8:38 PM CT

A fly's tiny brain may hold huge human benefits

COLUMBIA, Mo. Before swatting at one of those pesky flies that come out as the days lengthen and the temperature rises, one should probably think twice. A University of Missouri researcher has found, through the study of Drosophila (a type of fruit fly), that by manipulating levels of certain compounds linked to the circuitry of the brain, key genes correlation to memory can be isolated and tested. The results of the study may benefit human patients suffering from Parkinsons disease and could eventually lead to discoveries in the therapy of depression.

The implication for human health is that it could influence our understanding of the cognitive decline linked to Parkinsons disease and depression in humans, said Troy Zars, MU assistant professor of biological science in the College of Arts and Science.

The idea that animals have a system that can match the quality of a memory with the significance of the memory is well established. If the event is significant, the memory and detail surrounding it is much stronger, lasts longer and is more easily recalled in comparison to more insignificant or common events. The problem the study addresses is the understanding of the mechanism by which that occurs.

We have developed a strategy to address how this matching occurs, so we can turn that crank over and over again. It allows us to answer the questions, What gene is it" How does it function" How does it interact with other proteins" We can find brand-new, completely unexpected things, Zars said......... Posted by: Kelly      Read more         Source

March 24, 2008, 8:25 PM CT

Corn's roots dig deeper into South America

Corn has long been known as the primary food crop in prehistoric North and Central America. Now it appears it may have been an important part of the South American diet for much longer than previously thought, as per new research by University of Calgary archaeologists who are cobbling together the ancient history of plant domestication in the New World.

In a paper reported in the March 24 advanced online edition of the Proceedings of the National Academy of Sciences (PNAS), U of C PhD student Sonia Zarrillo and archaeology professor Dr. Scott Raymond report that a new technique for examining ancient cooking pots has produced the earliest directly dated examples of domesticated corn (maize) being consumed on the South American continent. Their discovery shows the spread of maize out of Mexico more than 9,000 years ago occurred much faster than previously believed and provides evidence that corn was likely a vital food crop for villages in tropical Ecuador at least 5,000 years ago.

The domestication and dispersal of maize has been a hot topic in archaeology for decades and these are the earliest indisputable dates for its presence in South America, Raymond said. It has long been thought that maize may have been used south of Panama at this time for ritual purposes but this shows it was also being consumed as food......... Posted by: Erica      Read more         Source

March 24, 2008, 7:36 PM CT

Ants as fungus farmers

It turns out ants, like humans, are true farmers. The difference is that ants are farming fungus.

Entomologists Ted Schultz and Sen Brady at the Smithsonians National Museum of Natural History have published a paper in the March 24 issue of the journal Proceedings of the National Academy of Sciences, providing new insight into the agricultural abilities of ants and how these abilities have evolved throughout time. Using DNA sequencing, the researchers were able to construct an evolutionary tree of fungus-growing ants, which revealed a single pioneering ancestor that discovered agriculture approximately 50 million years ago.

In the past 25 million years, four different specialized agricultural systems have evolved, leading to the most recently evolved and best-known fungus-growing ant speciesleaf-cutter ants. The ants do not eat the leaves; they grow their fungus gardens on them and then eat the fungus. By studying the agricultural evolution of leaf-cutter ants, as well as various other species, researchers may be able to develop improved human agricultural and medical methods.

Agriculture is very rare in the animal world, said Schultz. We only know of four animal groups that have discovered agriculture: ants, termites, bark beetles and humans. By studying certain fungus-growing ants, which our study indicates are almost like living fossils, we might be able to better understand steps involved in the evolution of ant agriculture......... Posted by: Kelly      Read more         Source

March 24, 2008, 7:34 PM CT

Model offers new understanding of cell signaling

Looking for answers in the bright light of day, rather than the confined beam of a street light at night. Thats how University of Michigan researcher Sofia Merajver, M.D., Ph.D., describes the power of a new mathematical model that could have far-reaching impact on how researchers study cellular signaling pathways.

This has the potential to be a true paradigm shift, says Merajver, a professor in the U-M Department of Internal Medicine and co-director of the Breast Oncology Program at the U-M Comprehensive Cancer Center. She is the senior author of a study about the new model published online March 21 in Plos Computational Biology.

Around the world, scientists scrutinize the pathways inside cells where signals travel and activate or suppress thousands of cell functions. The scientists want to learn which cellular processes are key in causing disease conditions and how to target them with new drugs. Understanding the full complexity of signaling pathways and their interactions is critical in discovering effective therapys for cancer, inflammation and other conditions that affect millions of people.

The full description of the new model in the article immediately offers researchers the opportunity to improve current mathematical models with a superior tool that can take advantage of advances in computing power, says Merajver......... Posted by: Janet      Read more         Source

March 20, 2008, 7:15 PM CT

Deadly genetic disease prevented before birth

By injecting a customized "genetic patch" into early stage fish embryos, scientists at Washington University School of Medicine in St. Louis were able to correct a genetic mutation so the embryos developed normally.

The research could lead to the prevention of up to one-fifth of birth defects in humans caused by genetic mutations, as per the authors.

Erik C. Madsen, first author and an M.D./Ph.D. student in the Medical Scientist Training Program at Washington University School of Medicine, made the groundbreaking discovery using a zebrafish model of Menkes disease, a rare, inherited disorder of copper metabolism caused by a mutation in the human version of the ATP7A gene. Zebrafish are vertebrates that develop similarly to humans, and their transparency allows scientists to observe embryonic development.

Children who have Menkes disease have seizures, extensive neurodegeneration in the gray matter of the brain, abnormal bone development and kinky, colorless hair. Most children with Menkes die before age 10, and therapy with copper is largely ineffective.

The research is published this month in the Proceedings of the National Academy of Sciences' advance online edition.

The development of organs in the fetus is nearly complete at a very early stage. By that time, the mutation causing Menkes disease has already affected brain and nerve development......... Posted by: Kelly      Read more         Source

March 18, 2008, 9:09 PM CT

Conditions for Spanish brown bears

Brown bears from the Iberian Peninsula are not as genetically different from other brown bears in Europe as was previously thought. An international study being published this week in Proceedings of the National Academy of Sciences, PNAS, shows that, on the contrary, the Spanish bear was only recently isolated from other European strains. These findings shed new light on the discussion of how to save the population of Spanish bears.

The scientists extracted DNA and determined the gene sequence of bears from prehistoric material, primarily from the Iberian Peninsula. Some of the material was as much as 80,000 years old. When the data material was analyzed, what emerged was a totally unexpected pattern.

We expected to be able to follow the Spanish brown bear far back in time, but we found to our amazement that it had genetic material from bears in other parts of Europe. In fact, it seems that the Spanish bear was isolated for the first time in our own time, says doctoral student Cristina Valdiosera, who performed most of the laboratory and analytical work.

These bears have possibly been isolated in Spain for a few thousand years, which is a very short period in an evolutionary perspective. In other words, there has been a flow of genes to and from the Iberian Peninsula throughout most of the time brown bears have been there. This is extremely interesting data when we discuss transporting bears from other areas to Spain for the purpose of preservation, says Anders Gtherstam, who directed the study......... Posted by: Kelly      Read more         Source