May 23, 2007, 8:05 PM CT

One in six European mammals threatened with extinction

The first assessment of all European mammals, commissioned by the European Commission and carried out by the World Conservation Union (IUCN), shows that nearly one in every six mammal species is now threatened with extinction. The population trends are equally alarming: a quarter (27%) of all mammals has declining populations and a further 33% had an unknown population trend. Only 8% were identified as increasing, including the European bison, thanks to successful conservation measures.

Europe is now home to the world's most threatened cat species, the Iberian Lynx, and the world's most threatened seal, the Mediterranean Monk Seal, both classified as Critically Endangered.

Environment Commissioner Stavros Dimas said: "The results of the report highlight the challenge we currently face to halt the loss of biodiversity by 2010, as European governments have promised. It is clear that the full implementation of the Habitats Directive, which covers nearly all mammals found threatened in this assessment, is of utmost importance to protect Europe's species".

World Conservation Union (IUCN) Director-General Julia Marton-Lefèvre said: "This new assessment proves that a number of European mammals are declining at an alarming rate. However, we still have the power to reverse that trend, as the case of the European bison which was brought back from extinction clearly shows."........ Posted by: Kelly      Read more         Source

May 23, 2007, 8:02 PM CT

Plants that produce more vitamin C

UCLA and Dartmouth researchers have identified a crucial enzyme in plant vitamin C synthesis, which could lead to enhanced crops. The discovery now makes clear the entire 10-step process by which plants convert glucose into vitamin C, an important antioxidant in nature.

"If we can find ways to enhance the activity of this enzyme, it may be possible to engineer plants to make more vitamin C and produce better crops," said Steven Clarke, UCLA professor of chemistry and biochemistry, director of UCLA's Molecular Biology Institute and co-author of the research study, would be published as a 'Paper of the Week' in the Journal of Biological Chemistry and currently available online.

"We hit on gold," Clarke said, "because we now have a chance to improve human nutrition and to increase the resistance of plants to oxidative stress. Plants may grow better with more vitamin C, particularly with more ozone in the atmosphere due to pollution".

Carole Linster, a UCLA postdoctoral fellow in chemistry and biochemistry and lead author of the study, discovered the controlling enzyme, GDP-L-galactose phosphorylase, which serves as the biosynthetic pathway by which plants manufacture vitamin C.

"Our finding leads to attractive approaches for increasing the vitamin C content in plants," Linster said. "We now have two strategies to provide enhanced protection against oxidative damage: Stimulate the endogenous activity of the identified enzyme or engineer transgenic plants which overexpress the gene that encodes the enzyme"......... Posted by: Erica      Read more         Source

May 17, 2007, 7:27 PM CT

Colorado River streamflow history

An epic drought during the mid-1100s dwarfs any drought previously documented for a region that includes areas of Arizona, Colorado, New Mexico, Utah and Wyoming.

The six-decade-long drought was remarkable for the absence of very wet years. At the core of the drought was a period of 25 years in which Colorado River flow averaged 15 percent below normal.

The new tree-ring-based reconstruction documents the year-by-year natural variability of streamflows in the upper Colorado River basin back to A. D. 762, said the tree-ring researchers from The University of Arizona in Tucson who led the research team.

The work extends the continuous tree-ring record of upper Colorado streamflows back seven centuries earlier than prior reconstructions.

"The biggest drought we find in the entire record was in the mid-1100s," said team leader David M. Meko, an associate research professor at UA's Laboratory of Tree-Ring Research. "I was surprised that the drought was as deep and as long as it was.

Colorado River flow was below normal for 13 consecutive years in one interval of the megadrought, which spanned 1118 to 1179.

Meko contrasted that with the last 100 years, during which tree-ring reconstructed flows for the upper basin show a maximum of five consecutive years of below-normal flows......... Posted by: Erica      Read more         Source

May 17, 2007, 7:04 PM CT

Spread Of Rabies In Raccoon Outbreak

Analyzing 30 years of data detailing a large rabies virus outbreak among North American raccoons, scientists at Emory University have revealed how initial demographic, ecological and genetic processes simultaneously shaped the virus's geographic spread over time. The study appears online in the Proceedings of The National Academy of Sciences.

"Our study demonstrates the combined evolutionary and population dynamic processes characterizing the spread of a pathogen after its introduction into a susceptible host population," says Leslie Real, PhD, Emory University Asa G. Candler professor of biology. During invasion, emerging pathogens, such as rabies, ebola and hantavirus, undergo rapid evolution while expanding their numbers and geographic range; yet, it is difficult to demonstrate how these processes interact, says Dr. Real.

However, this particular outbreak, which went largely unchecked until relatively recently, was uncommonly well documented both spatially and temporally. Data were methodically collected and stored since the outbreak began in the mid-1970s. In addition, the Centers for Disease Control and Prevention (CDC) had been stockpiling viral samples from the outbreak since 1982, giving researchers a treasure trove of genetic data ripe for analysis......... Posted by: Kelly      Read more         Source

May 16, 2007, 5:13 PM CT

Useful Traits in Wild Cottons

If you have Mom's smile, Dad's eyes and Grandpa's laugh, you might wonder what other traits you picked up from the genealogic fabric of the ol' family tree.

Researchers at the Texas A&M University System Agricultural Research and Extension at Lubbock are studying the family tree of cotton for much the same reason.

"Cotton genetic diversity has narrowed in recent years," said Dr. John Gannaway, Texas Agricultural Experiment Station cotton breeder. "A number of of today's successful commercial varieties share common parents and grandparents.

"A number of researchers believe today's varieties are flexible enough genetically to handle minor changes but lack enough diversity for really spectacular change. Aside from limiting fiber quality and yield potential, narrow genetics makes them more susceptible to insects and disease."

Gannaway and other researchers believe future progress in cotton breeding can only be achieved if sufficient genetic variability remains in global breeding stocks.

The mission of the center's Crops Genetic Research Facility is to investigate the potential of useful traits lying undiscovered in the gene pool or germplasm of obsolete and wild cottons contained in U.S., Russian and French cotton collections. These traits could help diversify the gene pool from which breeders draw new varieties in the future......... Posted by: Erica      Read more         Source

May 14, 2007, 10:45 PM CT

Remote Sensing Tools To Predict Bird Species Richness

Researchers at the Woods Hole Research Center, NASA Goddard Space Flight Center and the University of Maryland have taken a novel approach to studying biological diversity by making use of laser remote sensing (lidar). Lidar data provide unique measurements of the 3-dimensional structure of vegetation, an important aspect of habitat diversity. Habitat heterogeneity and complexity have been shown in a number of places to be directly correlation to animal species richness a more complex environment provides a greater number of ecological niches to be filled by different species. Using this basic principle, WHRC researchers examined the relationships between bird species richness and habitat metrics derived from lidar data acquired by aircraft. They then explored the efficacy of predicting bird richness and abundance based on these metrics. The first phase of this research, profiled in the current issue of Remote Sensing of Environment, focuses on results from study sites in the Patuxent Wildlife Refuge in Maryland.

As per Scott Goetz, a senior scientist at the Center who is leading the project, "Lidar is the most unique and exciting technology to come along in the past decade in the remote sensing research community. We now have the ability to characterize vegetation in three dimensions, and that has implications not only for biodiversity research but also for improved estimates of biomass and carbon stocks."........ Posted by: Erica      Read more         Source

May 14, 2007, 10:39 PM CT

Attach Genes To Minichromosomes

A team of researchers at the University of Missouri-Columbia has discovered a way to create engineered minichromosomes in maize and attach genes to those minichromosomes. This discovery opens new possibilities for the development of crops that are multiply resistant to viruses, insects, fungi, bacteria and herbicides, and for the development of proteins and metabolites that can be used to treat human illnesses.

In a paper reported in the Proceedings of the National Academy of Sciences (PNAS), Weichang Yu, Fangpu Han, Zhi Gao, Juan M. Vega and James A. Birchler built on a prior MU discovery about the creation of minichromosomes to demonstrate that genes could be stacked on the minichromosomes.

This has been sought for a long time in the plant world, and it should open a number of new avenues. If we can do this in plants, a number of advances could be done in agriculture that would not otherwise be possible, from improved crops to inexpensive pharmaceutical production to other applications in biotechnology, said Birchler, professor of biological sciences in the MU College of Arts and Science.

A minichromosome is an extremely small version of a chromosome, the threadlike linear strand of DNA and associated proteins that carry genes and functions in the transmission of hereditary information. Whereas a chromosome is made of both centromeres and telomeres with much intervening DNA, a minichromosome contains only centromeres and telomeres, the end section of a chromosome, with little else. However, minichromosomes have the ability to accept the addition of new genes in subsequent experiments......... Posted by: Janet      Read more         Source

May 14, 2007, 10:29 PM CT

Species Distribution Patterns In Tropical Forests

Looking at a rainforest its easy to see that there are hundreds of different tropical plant species that inhabit the forest. Eventhough the patterns of plant distributions in tropical forests have been widely studied, the reasonings behind these patterns are not as well known. This study, published in Nature, explores these patterns.

A contingent of scientists from around the world, including Panama, Gera number of, USA and Canada, have uncovered that tropical plant species distribution patterns are associated with the plants drought sensitivity.

For this study, the scientists conducted irrigation experiments on 48 native tree and shrub species to determine drought sensitivity between dry and irrigated conditions, which confirmed that species vary widely in drought sensitivity. The scientists also assessed regional plant species distribution across two large plots on opposite sides of the Isthmus of Panama. Through this assessment it was observed that the plants densities at the dry Pacific side in comparison to the wet Atlantic side correlated negatively with drought sensitivity.

"Our results suggest that niche differentiation with respect to soil water availability is a direct determinant of the distributions of tropical plant species," said Dr. Mel Tyree, University of Alberta researcher......... Posted by: Erica      Read more         Source

May 10, 2007, 10:34 PM CT

A Zookeeper's Adventuresin Belize

In February, Prospect Park Zoo keeper Crystal DiMiceli visited Belize, but unlike most travelers to this Central American country, she didn't go there for sandy beaches and tropical drinks. Instead, she went for business. Monkey business.

DiMiceli joined other staff from the Wildlife Conservation Society (WCS) zoos to participate in a survey to identify and count black howler monkeys over a three-week period. WCS has been working since 1992 to re-establish a population of these monkeys in southern Belize's Cockscomb Basin Wildlife Sanctuary and Jaguar Reserve.

Howler monkeys disappeared from Cockscomb by the late 1970s, due to a series of natural and man-made disasters that occurred before the reserve was created. From 1992 to 1994, 14 troops-62 animals in total-were relocated from a sanctuary in northern Belize and released as family units in the reserve. Until the zoo staff returned in 2006, there had been no follow-up counts of the Cockscomb troops. Though visitors and scientists had reported seeing or hearing the howler monkeys-known for their deep, loud calls-it was unknown whether the population had grown in the intervening years.

During their time in the jungle, DiMiceli and the other WCS staff worked with volunteers, field assistants, and park wardens to track the monkeys, recording howling and other evidence of their nearby activity. The group hiked and camped throughout the Cockscomb reserve as they conducted their monkey business, trading conference calls for howler calls and power lunches for trail mix. They followed the monkey groups they encountered, recording their sex and estimating ages. With each sighting, they recorded the locations on a global positioning unit, later entering this data on a map......... Posted by: Janet      Read more         Source

May 10, 2007, 10:29 PM CT

Asymmetry due to Perfect Balance

Cortical polarity is a prerequisite for a variety of cellular processes like cell division, local cellular growth, the secretion of substances and a number of steps in the embryonic development of organisms. To establish an asymmetric distribution of membrane proteins, diffusion has to be countered for a long enough time to allow the molecules to accumulate and fulfill their functions. This is possible through active and directed transport whose net effects need to outdo diffusion till the necessary concentration of molecules is reached. "We wanted to know which principles allow the establishment and maintenance of cortical polarity - and to quantify their respective roles," says Wedlich-Soldner. Apart from diffusion which prevents locally elevated concentrations of molecules there are only two other cellular mechanisms that influence the distribution of membrane proteins. The already mentioned active transport processes rely on structures of the cytoskeleton to move molecules or whole organelles in specific directions. The process of endocytosis, conversely, allows cells to absorb membrane molecules by forming vesicles out of small portions of the cell membrane.

For their study the research team used a well-characterised model system: Budding yeast cells expressing activated Cdc42, a central regulator of cortical polarity. Mutations in Cdc42 can hinder the establishment or maintenance of cell polarity and thus lead to the development of cancer. As so-called oncogenes some of the protein's activators have also been shown to cause tumour growth. The asymmetric distribution of Cdc42 in the cell membrane creates an area with elevated concentrations of that molecule, which is defined as a cap. This site is used as a marker for the growth of a daughter cell during cell division. To establish a cap Cdc42 molecules have to accumulate in a small region of the cell membrane and it is important that this area is defined with high precision. The new data show that this is achieved mainly through endocytosis. This process internalises parts of the plasma membrane through small vesicles - in the process removing Cdc42 as well. As Cdc42 in the centre of a cap is replenished through directed transport, endocytosis mainly leads to a sharpening of the cap edges. "We've seen for the first time how cells are able to establish caps with near perfect spatial precision", says Wedlich-Soldner. "It looks almost like a cut-off"......... Posted by: Janet      Read more         Source