August 23, 2007, 10:20 PM CT

Emphasis on conifer forests places multiple species at risk

CORVALLIS, Ore. The traditional emphasis on dense, fast-growing, conifer-dominated forests in the Pacific Northwest raises questions about the health of dozens of animal species that depend on shrubs, herbs and broad-leaf trees, a new analysis by Oregon State University and the U.S. Geological Survey suggests.

At least 78 vertebrate species have been documented that require, in one way or another, the food or habitat provided by non-coniferous vegetation, and may be at increasing risk whenever forest management reduces the prevalence of these shrubs or trees, or specifically targets them for removal.

Wildlife species that depend on the resources provided by non-coniferous vegetation may not persist in forests where these components are scarce, the report said.

The study was just published in Forest Ecology and Management, by Joan Hagar, an affiliate faculty member of the Department of Forest Science at Oregon State University, and a wildlife biologist with the Forest and Rangeland Ecosystem Science Center of the U.S. Geological Survey, which funded the study.

Natural forests of the Pacific Northwest, Hagar said, have always been dominated by conifers. But they also provided a continuity of trees that are young and old, short and tall; diverse shrubs, particularly in the early stages of forest re-growth; gaps, snags and cavities; often a dozen or more hardwood tree species; and possibly hundreds of grass and herbacious plant species......... Posted by: Erica      Read more         Source

August 21, 2007, 6:22 PM CT

Molecules In Living Cells

Clemson University chemists have developed a method to dramatically improve the longevity of fluorescent nanoparticles that may someday help researchers track the motion of a single molecule as it travels through a living cell.

The chemists are exploiting a process called resonance energy transfer, which occurs when fluorescent dye molecules are added to the nanoparticles. Their findings will be reported at the 234th annual national American Chemical Society meeting Aug.19-24 in Boston.

If scientists could track the motion of a single molecule within a living cell it could reveal a world of information. Among other things, scientists could determine how viruses invade a cell or how proteins operate in the body. Such technology also could help doctors pinpoint the exact location of cancer cells in order to better focus treatment and minimize damage to healthy tissue. Outside the body, the technology could help speed up detection of such toxins as anthrax.

The key to developing single-molecule tracking technology may be the development of better fluorescent nanoparticles.

Fluorescent nanoparticles are thousands of times smaller than the width of a human hair and are similar in size to protein molecules, to which they can be attached. When illuminated by a laser beam inside a light microscope equipped with a sensitive digital camera, the nanoparticle attached to a protein will light up, allowing scientists to get a precise fix on the position of the protein and monitor its motion inside a cell......... Posted by: Janet      Read more         Source

August 21, 2007, 5:55 PM CT

Elephantnose fish 'see' with their chin

Originating in Central Africa, Peters' elephantnose fish (Gnathonemus petersii), finds its bearings by means of weak electrical fields. Researchers from the University of Bonn have now been able to show how well this works. In complete darkness the animals can even distinguish the material of objects at a distance or dead organisms from living ones. The results have now been reported in the Journal of Experimental Biology.

The fish, which is as long as a cigar, hovers with its head inclined, close to the gravel-covered bed. While it swims forward slowly, its trunk-like elongated chin sweeps steadily from right to left, always at a distance of a few millimetres from the bottom. This way the fish behaves like treasure hunters searching for buried gold coins on the beach with their metal detector. Basically, this is precisely what the fish is doing. Hidden in the sediment there are large numbers of dead nematocera larvae waiting for it, its favourite food.

Zoologists from the University of Bonn have hidden the larvae there. 'We wanted to see whether it can find them and if the answer is yes, then down to what depth,' Professor Gerhard von der Emde explains. 'It', that is the African Peters' elephantnose fish. Yet its characteristically shaped chin does not work like a especially sensitive nose. Instead, it contains more than 500 electric sensors with which it senses its surroundings. With this sense the animal has conquered the night. During the day it hides, only under cover of darkness does it goes searching for food......... Posted by: Kelly      Read more         Source

August 21, 2007, 5:11 PM CT

Antibiotic Resistance From Swine Farms To Groundwater

The routine use of antibiotics in swine production can have unintended consequences, with antibiotic resistance genes sometimes leaking from waste lagoons into groundwater.

In a new study, scientists at the University of Illinois report that some genes found in hog waste lagoons are transferred - "like batons" - from one bacterial species to another. The scientists observed that this migration across species and into new environments sometimes dilutes - and sometimes amplifies - genes conferring antibiotic resistance.

The new report, in the recent issue of Applied and Environmental Microbiology, tracks the passage of tetracycline resistance genes from hog waste lagoons into groundwater wells at two Illinois swine facilities.

This is the first study to take a broad sample of tetracycline resistance genes in a landscape dominated by hog farming, said principal investigator R.I. Mackie. And it is one of the first to survey the genes directly rather than focusing on the organisms that host them. Mackie is a professor in the department of animal sciences and an affiliate of the Institute for Genomic Biology.

"At this stage, we're not really concerned about who's got these genes," Mackie said. "If the genes are there, potentially they can get into the right organism at the right time and confer resistance to an antibiotic that's being used to treat disease"......... Posted by: Kelly      Read more         Source

August 20, 2007, 9:41 PM CT

Tracking feline memories on the move

When a cat steps over an obstacle with its front legs, how do its hind legs know what to do" A new study in the August 21st issue of Current Biology, a publication of Cell Press, reveals that it is the foreleg stepping movement itself that leaves a lasting impression. By comparison, feline memories of having just seen an obstacle proved rather fleeting.

Indeed, the scientists observed that cats could remember having stepped over a hurdle for at least ten minutes. The findings suggest that cats working memories can extend much longer than earlier studies had shown, as per the researchers.

"We've observed that the long-lasting memory for guiding the hind legs over an obstacle requires stepping of the forelegs over the obstacle," said Keir Pearson of the University of Alberta, Canada. The main surprise was how short lasting the visual memory on its own wasjust a few seconds when animals were stopped before their forelegs stepped over the obstacle.

The scientists examined the animals memories by stopping cats after their forelegs, but not their hind legs, had cleared an obstacle. They then distracted the animals with food and lowered the obstacle into the walking surface. The nature of the subsequent step revealed whether the animal remembered having stepped over the disappearing obstacle. To find out whether the cats remembered what they saw versus what they did, Pearsons group repeated the experiment, but this time they stopped the cats just before they made their first step......... Posted by: Kelly      Read more         Source

August 16, 2007, 8:53 PM CT

Ginkgo: Tools for product analysis or quality

The National Institute of Standards and Technology (NIST) has issued a suite of Standard Reference Materials (SRMs) for ginkgo biloba, one of the most popular dietary supplements in the marketplace, with annual worldwide sales estimated at $1 billion.

The NIST reference materials are designed to help scientists validate the accuracy of analytical methods for flavonoids and terpene lactones (plant constituents that may be linked to the perceived effectiveness of ginkgo) as well as toxic elements in ginkgo*. In addition to supporting measurements linked to clinical trials or verifying product label claims, the reference materials also can be used by dietary supplement manufacturers to improve product consistency.

The fruits and seeds of the female ginkgo are used for a variety of purposes in traditional Chinese medicine. In the West, dietary supplements are more usually formulated from ginkgo leaves and standardized leaf extracts. They are used in the therapy of asthma, bronchitis, fatigue and tinnitus (ringing in the ears); for memory improvement and for the prevention and therapy of Alzheimers disease, eventhough these uses have not been backed by rigorous clinical trials. Ginkgo biloba contains a family of chemical constituents known as ginkgolides which have been linked to reduced platelet aggregation. The National Institute of Healths (NIH) National Center for Complementary and Alternative Medicine (NCCAM) notes promising results in many areas, but says larger, well-designed research studies are needed......... Posted by: Erica      Read more         Source

August 15, 2007, 9:28 PM CT

Avoiding incest by causing male relatives to leave home

Scientists at the University of Sheffield in the UK and Leibniz Institute for Zoo and Wildlife Research (IZW) in Berlin, Gera number of, have observed that female hyenas avoid inbreeding with their male relatives by giving them little choice but to leave their birth group.

Animals generally avoid inbreeding because it is genetically hazardous. They can either do this by moving away from home or, like humans, by learning who their relatives are and not mating with them.

Like most mammals though, male hyenas do not contribute to the rearing of their offspring, making it highly unlikely that females know who their father is. Instead males decide to leave the group in which they were raised, resulting in a low level of inbreeding.

But until now, little was known about why the males and not the females decided to move away from home. The new research on spotted hyenas, published in Nature this week, shows that the reason most males move from their natal group is because of female mate-choice the rules females use when choosing which of the a number of male group members will sire their offspring.

The scientists observed that young females prefer to mate with new arrivals in a group - those males born into, or who joined, the group after the female was born. Older females also apply this rule and in addition prefer males that have built friendly relationships with them for several years. These mate preferences of females mean that males have to choose groups with a high number of young females if they want to reproduce successfully......... Posted by: Kelly      Read more         Source

August 15, 2007, 9:13 PM CT

First all-African GM crop is resistant to maize streak virus

The first all-African genetically modified crop plant with resistance to the severe maize streak virus (MSV), which seriously reduces the continents maize yield, has been developed by researchers from the University of Cape Town and PANNAR PTY Ltd, a South African seed company. The research, published in Plant Biotechnology Journal represents a significant advance in African agricultural biotechnology, and will play an important role in alleviating Africas food shortages and famine.

Dr Dionne Shepherd, lead researcher explains, MSV is transmitted to maize by small insects called leafhoppers. The disease is therefore a result of a complex interplay between the plant, the virus and insect. Factors that can influence the severity of the disease include the age at which the plant is infected (the younger the plant, the more severe the infection), the maize variety (some are more susceptible than others), and environmental conditions.

We have created an MSV-resistant maize variety by genetic engineering, using an approach known as pathogen-derived resistance. This means that a gene from the viral pathogen is used to protect the plant from that pathogen. We mutated a viral gene that under normal circumstances produces a protein that is essential for the virus to replicate itself and inserted it into the maize plants genome, creating genetically modified maize. When the virus infects one of these transgenic maize plants, it displays a significant delay in symptom development, a decrease in symptom severity and higher survival rates than non-transgenic plants......... Posted by: Erica      Read more         Source

August 15, 2007, 8:26 PM CT

Male elephants get 'photo IDs' from scientists

Asian elephants dont carry photo identification, so researchers from the Wildlife Conservation Society and Indias Nature Conservation Foundation are providing the service free of charge by creating a photographic archive of individual elephants, which can help save them as well.

The scientists have developed a unique photographic capture-recapture survey method that identifies individual male elephants, specifically by the shape and size of their tusks, ears, and other features. This in turn can be used to monitor their survival rates and movement, as per a new study reported in the current issue of the Journal Animal Conservation (10: 391-399).

Unlike African elephants where both males and females have tusks, only male Asian elephants have valuable tusks, so they are specifically targeted by poachers, said WCS researcher Varun Goswami, the studys lead author. In light of this fact, just counting all elephants with generic techniques isnt enough. Our new method allows specific tracking of male elephant population dynamics, so it is a powerful conservation tool.

Working in collaboration with the Karantaka State Forest Department in Nagarahole and Bandipur reserves, scientists systematically took more than 2400 photographs of individual elephants, sampling game roads and waterholes over an 80-day period. Male elephants in particular were given special therapy, with the researchers recording data such as tusk length, thickness, angle, arrangement, as well as other characteristics ear shape, shoulder height, tail length, and scars. These data revealed some 134 individual male elephants in a population of 991 elephants, with an adult male/female ratio of 1 to 4.33. The data were analyzed using advanced open capture-recapture models......... Posted by: Kelly      Read more         Source

August 15, 2007, 8:25 PM CT

Emerging (disease) markets

Instead of attacking wild birds for our new disease problems, a far more cost effective approach should focus on keeping wild animals separate in the places where they often commingle: in wildlife markets and international trade, as per wildlife health experts from the Wildlife Conservation Society (WCS) and the United Nations Food and Agriculture Organization (FAO) in a recent issue of the prestigious Journal of Wildlife Diseases.

This is an ounce of prevention that we really need to use in trading hubs where human commerce of wild animals allows for the spread of diseases, said Dr. William Karesh, director of the Wildlife Conservation Societys Field Veterinary Program and lead author of the peer-evaluated paper titled Implications of wildlife trade on the movement of avian influenza and other infectious diseases. The wildlife trade, and markets in particular, serve as very dirty mixing bowls for diseases. We can significantly reduce the threat of avian flu and other emerging diseases by decreasing contact among different animal species in markets and thus giving pathogens fewer opportunities to mutate and spread.

In the paper, Karesh and his co-authors point out birds and other animals moving through wildlife markets give pathogens a chance to jump into new species and geographic regions via the global trade in wildlife. For example, two instances of highly pathogenic avian influenza traveling vast distances in bird hosts include two mountain hawk eagles that were illegally smuggled from Thailand to Belgium and wild songbirds shipped from Taiwan to the United Kingdom. Besides direct health effects, disease outbreaks damage regional and global economies by destabilizing trade. Disease outbreaks such as SARS, Nipah virus and others are thought to have cost some $80 billion in economic damage. Efforts to control avian influenza, such as a culling of 140 million chickens in Asia entailed a significant cost and in developing countries, a terrible loss of food and income for families dependent on those animals......... Posted by: Kelly      Read more         Source