May 17, 2006, 10:16 PM CT

What Do Black Bears Eat?

Black bears may be the least carnivorous of the "carnivores" of North America. They consume a wide variety of seasonally abundant herbs, forbs, fruits, berries, nuts, and other plant parts and products. The specific plants may differ among the a number of ecoregions of North America. However, certain trends are evident. Spring foods are predominantly grasses, sedges, shoots and other high-protein lush green vegetation. Deer and other carcasses may be scavenged, as well as leftover nuts. Skunk cabbage is important in Massachusetts and squaw root in the southern Appalachians. During summer, bears shift to energy-rich "soft mast" foods such as huckleberries, blackberries, raspberries, grapes, and cherries. Protein-rich insects such as ants, wasps, and beetle larvae are usually taken.

Crayfish, frogs, birds' eggs, mice, red squirrels, woodchucks, snowshoe hare, and other animal food are occasionally eaten. Then, in autumn (where available), "hard mast" items including acorns, hickory nuts, beechnuts, hazelnuts, pine nuts, and similar foods are taken. Corn is also eaten where available. Bears can make tremendous weight gains in fall, as much as 3 to 4 lbs. per day. However, in northern areas, where hard mast is lacking, bears must rely only on berry crops for weight gain and den after those are exhausted. Bears, especially adult males, and especially when foods are scarce, may travel up to 125 miles outside their home range in late summer and early fall to a concentrated food source before returning home to den. A number of historical accounts from Louisiana, Minnesota, New England, Ontario, Wisconsin, and elsewhere mention these "migrations" or "forays", which often followed well-defined trails beaten down over time.........

Posted by: Kelly      Permalink         Source

May 16, 2006, 11:00 PM CT

Small Molecule Interactions Were Central To The Origin Of Life

In an important new paper forthcoming in the recent issue of The Quarterly Review of Biology, Robert Shapiro (New York University) argues against the widely held theory that the origin of life began with the spontaneous appearance of a large, replicating molecule such as RNA. Instead, Shapiro raises an alternative that does not depend on a "stupendously improbable accident," presenting the more plausible idea that life began within a mixture of simple organic molecules, multiplied through catalyzed reaction cycles and an external source of available energy.

"The diversity of organic chemistry, with its harvest of competing, interconnected reactions, becomes an asset rather than a liability in the case of the energy-driven system," explains Shapiro. "The existence of side reaction paths can provide the network with the capacity of reacting to circumstances."

Shapiro outlines how replicator theories, though they have been supported by "prebiotic" syntheses carried out by chemists using modern apparatus and purified reagents, are highly unlikely. The creation of a molecule that can self-replicate requires the combination of diverse chemicals in a long sequence of reactions in a specific order, interspersed by complicated separations, purifications, and changes in locale.........

Posted by: Erica      Permalink         Source

May 16, 2006, 0:14 AM CT

Plants Tell Caterpillars When It's Safe To Forage

The world is filled with cues that could influence the daily feeding patterns of an organism. A number of plants, for example, respond to foraging damage by releasing specialized chemical signals - volatile organic compounds that evaporate in the air - that attract the forager's natural enemies. This strategy is obviously no use against a cow, but proves effective when the offender is a caterpillar and the summoned predator is a wasp. Just how much control such biotic factors exert over a forager's daily routine has remained an open question. But in a new study in the open access journal PLoS Biology, Kaori Shiojiri, Rika Ozawa, and Junji Takabayashi show that plant signals can indeed regulate herbivore behavior.

When the larvae of beet armyworms (Spodoptera exigua) feed on corn, the plant releases volatile compounds that act as a magnet for parasitic wasps (Cotesia marginiventris), which deposit their eggs in the larvae. Production of volatile chemicals increases during the day (when wasps are active) and decreases at night, suggesting that variations in production might affect the daily activity patterns of foraging larvae, with low production sending the signal that the coast is clear. To test this hypothesis, Shiojiri et al. exposed larvae of a corn-munching nocturnal caterpillar, Mythimna separata, to volatile compounds from corn and varied the light and dark conditions for both corn and insect. Corn infested with M. separata releases volatiles that attract parasitic wasps (C. kariyai).........

Posted by: Erica      Permalink         Source

May 16, 2006, 0:07 AM CT

Global Warming May Have Damaged Coral Reefs Forever

Global warming has had a more devastating effect on some of the world's finest coral reefs than previously assumed, suggests the first report to show the long-term impact of sea temperature rise on reef coral and fish communities.

Large sections of coral reefs and much of the marine life they support may be wiped out for good, say the international team of researchers, who surveyed 21 sites and over 50,000 square metres of coral reefs in the inner islands of the Seychelles in 1994 and 2005.

Their report is the first to show the long-term impact of the 1998 event where global warming caused Indian Ocean surface temperatures to increase to unprecedented and sustained levels, killing off (or 'bleaching') more than 90 per cent of the inner Seychelles coral.

The team, led by the University of Newcastle upon Tyne, and which comprises scientists from the UK, Australia and the Seychelles, publishes its findings today, Monday May 15, in the Proceedings of the National Academy of Sciences.

The research showed that, while the 1998 event was devastating in the short term, the main long-term impacts are down to the damaged reefs being largely unable to reseed and recover. A number of simply collapsed into rubble which became covered by unsightly algae.........

Posted by: Erica      Permalink         Source

May 10, 2006, 0:18 AM CT

Importance Of Fungi In Arctic Nitrogen Cycle

A new method to calculate the transfer of nitrogen from Arctic mushrooms to plants is shedding light on how fungi living symbiotically on plant roots transfer vital nutrients to their hosts. The analytical technique, developed by John E. Hobbie, MBL Distinguished Scientist and co-director of the laboratory's Ecosystems Center and his son, Erik A. Hobbie of the University of New Hampshire, may be applied to nearly all conifers, oaks, beeches, birch and shrubs such as blueberry and cranberry-all nitrogen-poor ecosystems-and will be an important tool for future studies of plant nitrogen supply.

It has long been known when soil nitrogen is in short supply, mycorrhizal fungi (those living symbiotically on the roots of plants) transfer nutrients to their host plants in exchange for plant sugars derived from photosynthesis, but the rates of transfer have never been quantified in the field. John and Erik Hobbie's study, published in the April 2006 issue of the journal Ecology, quantifies the role.

of mycorrhizal fungi in nitrogen cycling for the first time through measurements of the natural abundance of nitrogen isotopes in soils, mushrooms and plants. The researchers tested their technique using data from the Arctic LTER (Long Term Ecological Research) site near Toolik Lake, Alaska, in the northern foothills of the Brooks Range.........

Posted by: Erica      Permalink

May 8, 2006, 9:14 PM CT

Two New Varieties of Non-Allergenic Soybeans

Soy is also a very common ingredient in a lot of food products, usually as fillers and extenders. For a lot of vegetarians, it is also a common alternative to meat because of its high protein cotent. However, a considerable number of people, particularly children, show allergic reactions such as skin rashes, gastrointestinal problems, or in more serious cases, swelling and diffulty of breathing and swallowing. If not for this, soy would have been an ideal food item, considering its nutritional value and relatively cheap price.

This is why scientists have tried to create genetically modified soybeans that are non-allergenic. They simply shut off that gene called p34, which has been found to be responsible for producing the protein that invokes allergic reactions. However, because of public resistance to GMOs, they tried other traditional approaches as well.

Alas, researchers from the University of Illinois and the USDA-Agricultural Research Service have been rewarded. After screening more than 16,000 soybean lines in the USDA's National Soybean Germplasm Collection, they found two varieties that are naturally deficient in the allergy-causing P34 protein. They said they will release these soybean varieties without patents to companies and breeders. Hopefully it doesn't take long before we consumers see them on the store shelves!........

Posted by: Erica      Permalink         Source

May 6, 2006, 5:50 PM CT

No-Mow Grass May Be Coming Soon

For anyone tethered to a lawnmower, the Holy Grail of horticultural accomplishment would be grass that never grows but is always green.

Now, that vision of suburban bliss-and more-seems plausible as scientists have mapped a critical hormone signaling pathway that regulates the stature of plants. In addition to lawns that rarely require mowing, the finding could also enable the development of sturdier, more fruitful crop plants such as rice, wheat, soybeans, and corn.

In a paper published in the May 4, 2006, issue of the journal Nature, Howard Hughes Medical Institute scientists report they have deciphered the signaling pathway for a key class of steroid hormones that regulates growth and development in plants.

"By manipulating the steroid pathway.we think we can regulate plant stature and yield," said Joanne Chory, a Howard Hughes Medical Institute investigator at the Salk Institute for Biological Studies, and the senior author of the new report.

Manipulation of plant stature has been a longstanding goal in horticulture, agronomy, and forestry. The ability to precisely control plant size would have broad implications for everything from urban forestry to crop and garden plant development. Beyond perpetually short grass, trees could be made more compact for better growth in crowded cities, and berry bushes could be made taller for ease of harvesting.........

Posted by: Erica      Permalink         Source

May 4, 2006, 5:06 PM CT

'Cellular Antennae' On Algae

By studying microscopic hairs called cilia on algae, scientists at UT Southwestern Medical Center have found that an internal structure that helps build cilia is also responsible for a cell's response to external signals.

Cilia perform a number of functions on human cells; they propel egg and sperm cells to make fertilization possible, line the nose to pick up odors, and purify the blood, among other tasks.

With such a range of abilities, cilia serve as both motors and "cellular antennae," said Dr. William Snell, a professor of cell biology at UT Southwestern and senior author of new research on cilia reported in the May 5 issue of Cell.

Genetic defects in cilia can cause people to develop debilitating kidney disease or to be born with learning disabilities, extra fingers or toes, or the inability to smell.

But no one really knows how cilia work, or, in some parts of the body, what their function is.

"There are cilia all over within our brain, and we don't have a clue about what they're doing," Dr. Snell said.

He and his team use the microscopic green alga, Chlamydomonas reinhardtii, which has two individual cilia. This alga allows scientists to manipulate genes and study the resulting effects on cilia in a way that would be impossible in animals such as mice.........

Posted by: Erica      Permalink         Source

May 4, 2006, 4:44 PM CT

Use Of Switchgrass Could Solve Energy Woes

Carnegie Mellon University researchers say the use of switchgrass could help break U.S. dependence on fossil fuels and curb costly transportation costs.

"Our report indicates the time is right for America to begin a transition to ethanol derived from switchgrass," said Scott Matthews, an assistant professor in the Civil and Environmental Engineering Department. A 25 percent hike in gas prices at the pump since December adds to the researchers' call for more ethanol derived from switchgrass, a perennial tall grass used as forage for livestock. Gasoline prices in the U.S. are approaching an average of $3 a gallon. The Carnegie Mellon findings were published in the May 1 issue of the American Chemical Society's Journal "Environmental Science and Technology".

Matthews, along with W. Michael Griffin, executive director of the Green Design Institute at Carnegie Mellon's Tepper School of Business, and William R. Morrow, a researcher in the university's Department of Civil and Environmental Engineering, said using switchgrass as a supplement to corn to make ethanol would help ensure the availability of large volumes of inexpensive ethanol to fuel distributors and consumers.

"We need to be thinking about how we can make and deliver ethanol once our corn and land resources are maxed out. Switchgrass can be that next step," Griffin said.........

Posted by: Erica      Permalink         Source

May 3, 2006, 10:56 PM CT

African Wetland Managers Armed With New Technology

Wetlands are a global environmental resource, both in terms of biodiversity and water management.
Earth's wetlands are vital to the water cycle and havens for wildlife, but they are under threat. GlobWetland, an ESA-led initiative in collaboration with the Ramsar Convention Secretariat, has been addressing this issue by using satellite imagery to provide detailed wide-area views of individual wetlands to aid national and local conservation efforts.

Because the success of wetland conservation ultimately comes down to individual wetland managers, the GlobWetland products and services are user-oriented and based on specific requests of users across 50 sites in 21 countries worldwide.

Based on user requirements, GlobWetland products include base maps, land use-land cover (LULC) maps and change detection maps - with historical Earth Observation (EO) satellite images being compared with current acquisitions to see what changes have occurred during the last ten years or more.

Integrating the EO-derived products and services into the user's traditional working procedures requires training to secure capacity building and to achieve a well-defined amount of competence. This is particularly important in Africa where the lack of updated geo-information and the inefficient in-situ monitoring networks hinder the conservation efforts of wetland managers and water authorities.........

Posted by: Erica      Permalink         Source