October 29, 2006, 7:45 PM CT

Untold Stories Of Elk Skeleton

Seeing the well-preserved antlers, skull and partial skeleton of a very large elk that was found in northern Wisconsin was impressive enough. But what really intrigued Jean Hudson was what was found nearby - a Clovis point, a type of spearhead used by hunters from about 10,000 years ago.

Very few have been found this far north, and this spearhead may be the one that doomed the animal all those millennia ago, says Hudson, an associate professor of anthropology. Or the two specimens could be completely unrelated, she says.

If the two are linked, it would mean that the elk remains are particularly rare. More physical evidence of animals such as mastodons, wooly mammoths and giant bison exists than that of elk, says Hudson.

But decoding the secrets of an animal skeleton requires asking the same questions you would at a crime scene investigation: What were the time, cause and circumstances of death? It also involves sometimes getting it wrong, leading to new questions.

A swimmer discovered the antlers of what appears to be a prehistoric elk at the bottom of Middle Eau Claire Lake in Barnes, Wis., last summer. Matt McKay of the Department of Natural Resources in Hayward, who is assigned to the maintenance of the Clam Lake elk herd, estimated the elk would have been between 1,000 and 1,100 pounds when it was alive.........

Posted by: Ashley      Permalink         Source

October 27, 2006, 9:02 PM CT

Mate-attracting Chemicals in Silk worms

It's all about "the birds and the bees." And now, "the silkworm moths and the fruit flies".

A chemical ecologist and a genetics researcher at the University of California, Davis, have joined forces to trick fruit flies into thinking that silkworm moths are potential mates.

Groundbreaking research in the labs of chemical ecologist Walter Leal and genetics researcher Deborah Kimbrell shows that genetically engineered fruit flies responded to the silkworm moth scent of a female.

The practical implications of the findings could be widespread. Methods that can attract or repel insects have important applications for agricultural pests and medical entomology. The research could lead to designing better chemicals to attract insects and designing better chemicals to suppress insect communication. That is because insects communicate or smell through their antennae.

Many insect species, including silkworm moths, release sex pheromones or chemical signals to attract a mate. "Silkworm moths utilize smell more strongly than any other senses," said Leal, professor and chair of the Department of Entomology. "Moths keep on the trail of a scent until they find a female".

"We got a very clear response," he said. "Our electrophysiological recordings and direct stimulation testing showed that the transgenic fruit flies definitely responded to the moth pheromone".........

Posted by: Ashley      Permalink         Source

October 26, 2006, 4:51 AM CT

Nuclear Receptors In Bee Genome

Susan Fahrbach, a Wake Forest University biologist, is among the more than 170 researchers who helped decode the honey bee genome. She contributed to the article on the bee genome sequence that appears in the Oct. 26 issue of Nature.

Her piece of the puzzle -- analyzing the nuclear hormone receptors found in the bee genome -- also appears in the current issue of Insect Molecular Biology.

The honey bee was chosen to have its genome sequenced because of its dual importance to agriculture and medicine. The well-known pollination activities of honey bees add billions of dollars of value to U.S. crops every year, but bees are also used in the laboratory to study issues related to human health such as immunity, longevity and diseases of the X chromosome. In addition, brain scientists are interested in the honey bee's complex social life and their ability to communicate the location of flowers to other members of the hive.

Fahrbach, Reynolds Professor of Developmental Neuroscience, and her co-researchers at Wake Forest and the University of Illinois, searched the genome sequence to find all of the nuclear receptors encoded in the bee genome. They found that the same nuclear receptors that control the development of the nervous system during the early.........

Posted by: Ashley      Permalink         Source

October 24, 2006, 8:23 PM CT

Soot from wood stoves impacts global warming

New measurements of soot produced by traditional cook stoves used in developing countries suggest that these stoves emit more harmful smoke particles and could have a much greater impact on global climate change than previously thought, as per a research studyscheduled to appear in the Nov. 1 issue of the American Chemical Society journal Environmental Science & Technology.

Perhaps as a number of as 400 million of these stoves, fueled by wood or crop residue, are used daily for cooking and heating by more than 2 billion people worldwide, as per the study's lead authors, Tami Bond, Ph.D., and doctoral candidate Chris Roden of the University of Illinois, Urbana-Champaign. In a field test in Honduras, the scientists observed that cook stoves there, which are similar to those used in other developing nations, produce two times more smoke particles than expected, based on prior laboratory studies. These dark, sooty particles, which are darker than those produced by grassland or forest fires, have a climate warming effect because they absorb solar energy and heat the atmosphere, as per Roden.

In earlier work, Bond estimated that burning firewood -- the principal fuel for cook stoves in the developing world -- produces 800,000 metric tons of soot worldwide each year. In comparison, diesel cars and trucks generate about 890,000 metric tons of soot annually. These two sources each account for about 10 percent of the soot emitted into the world's atmosphere each year, she said.........

Posted by: Tyler      Permalink         Source

October 24, 2006, 7:27 PM CT

New Theory For Mass Extinctions

A new theory on just what causes Earth's worst mass extinctions may help settle the endless scientific dust-up on the matter. Whether you favor meteor impacts, volcanic eruptions, cosmic rays, epidemics, or some other cause for the worst mass extinction events in Earth's history, no single cause has ever satisfied all researchers all the time for any extinction event. That may be because big extinctions aren't simple events.

The new Press/Pulse theory gets around the controversy by rejecting the all-or-nothing approach to mass extinction, calling instead on a combination of deadly sudden catastrophes - "pulses" - with longer, steadier pressures on species - "presses".

"What we wanted to do is move away from the idiosyncratic approach to extinction mechanisms and look for what these intervals had in common. If you have A and B you will get a mass extinction," said Ian West, a 2006 graduate of Hobart and William Smith Colleges in Geneva, NY.

West and Hobart and William Colleges paleontology professor Nan Crystal Arens are scheduled to present their work on the Press/Pulse theory on Wednesday, 25 October, at the Annual Meeting of the Geological Society of America in Philadelphia.

Using databases that chart genera of marine organisms and their extinctions through the fossil record, West and Arens divided the last 488 million years of geologic history into four groups: times of suspected impact events (Pulses), times of massive volcanic eruptions (Presses), times when neither Presses nor Pulses occurred, and times when Press and Pulse coincided. They compared average extinction rates in geologic stages in each of these groups.........

Posted by: William      Permalink         Source

October 24, 2006, 7:11 PM CT

Trotting With Emus To Walk With Dinosaurs

One way to make sense of 165-million-year-old dino tracks may be to hang out with emus, say paleontologists studying thousands of dinosaur footprints at the Red Gulch Dinosaur Tracksite in northern Wyoming. Because they are about the same size, walk on two legs and have similar feet, emus turn out to be the best modern version of the enigmatic reptiles that once trotted along a long-lost coastline in the Middle Jurassic.

"We don't have any documented dinosaur bones and teeth from that period in North America, except for some very scrappy material from Mexico," said Brent Breithaupt, curator and director of the University of Wyoming's Geological Museum in Laramie, Wyo. That makes it very hard to connect the tracks to a particular dinosaur. And of course, "We unfortunately can't go out and see walking dinosaurs today. Or can we?".

After scouring the dinosaur fossil record in other parts of the world and deciding that a human-sized, meat-eating dinosaur (theropod) fit the bill for the tracks at Red Gulch, Breithaupt and his colleagues and students did something unusual. Instead of speculating about what the dinosaurs were doing, they went hunting for a modern analog animal they could study to help decipher the tracks.

Large flightless birds are the most logical choice and are, along with all birds today, thought to be descended from dinosaurs. But not all of those alive today are good choices or easy to work with. Ostriches are two-toed and have an attitude problem, so that ruled them out, says Breithaupt. Rheas have three toes, but are "like working with a bunch of kindergarteners on too much sugar," he said.........

Posted by: William      Permalink         Source

October 22, 2006, 11:29 PM CT

Strange Bacteria Thriving Two Miles Underground

A Princeton-led research group has discovered an isolated community of bacteria nearly two miles underground that derives all of its energy from the decay of radioactive rocks rather than from sunlight. According to members of the team, the finding suggests life might exist in similarly extreme conditions even on other worlds.

The self-sustaining bacterial community, which thrives in nutrient-rich groundwater found near a South African gold mine, has been isolated from the Earth's surface for several million years. It represents the first group of microbes known to depend exclusively on geologically produced hydrogen and sulfur compounds for nourishment. The extreme conditions under which the bacteria live bear a resemblance to those of early Earth, potentially offering insights into the nature of organisms that lived long before our planet had an oxygen atmosphere.

The scientists, who hail from nine collaborating institutions, had to burrow 2.8 kilometers beneath our world's surface to find these unusual microbes, leading the scientists to their speculations that life could exist in similar circumstances elsewhere in the solar system.

"What really gets my juices flowing is the possibility of life below the surface of Mars," said Tullis Onstott, a Princeton University professor of geosciences and leader of the research team. "These bacteria have been cut off from the surface of the Earth for many millions of years, but have thrived in conditions most organisms would consider to be inhospitable to life. Could these bacterial communities sustain themselves no matter what happened on the surface? If so, it raises the possibility that organisms could survive even on planets whose surfaces have long since become lifeless".........

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October 22, 2006, 8:40 PM CT

How To Seal DNA Breaks

Scientists investigating an important DNA-repair enzyme now have a better picture of the final steps of a process that glues together, or ligates, the ends of DNA strands to restore the double helix.

The enzyme, DNA ligase, repairs the millions of DNA breaks generated during the normal course of a cell's life, for example, linking together the abundant DNA fragments formed during replication of the genetic material in dividing cells.

"Our study shows that DNA ligase switches from an open, extended shape to a closed, circular shape as it joins DNA strands together," says the study's senior author Tom Ellenberger, D.V.M, Ph.D., the Raymond H. Wittcoff Professor and head of the Department of Biochemistry and Molecular Biophysics at Washington University School of Medicine in St. Louis. "The ligase resembles a wristwatch that latches around the DNA ends that are being joined".

DNA is surprisingly reactive and under continuous assault from environmental toxins and reactive cellular metabolites. A means of repairing DNA damage is vital to maintaining the integrity of the genetic blueprint.

When these repair processes go awry, cells can malfunction, die or become cancerous, so researchers would like to know how "DNA mechanics" do their jobs. DNA ligases are attractive targets for the chemotherapy of cancer and other diseases.........

Posted by: Ashley      Permalink         Source

October 22, 2006, 7:46 PM CT

SRM Can Help Control Heavy Metal Content

A new reference material developed by the National Institute of Standards and Technology (NIST) can help the agriculture industry and state regulators monitor the concentrations of several potentially hazardous heavy metal contaminants in fertilizers.

Modern multi-nutrient fertilizers produced for home and agricultural use are formulated from multiple sources to provide significant amount of nitrogen, phosphorus and potassium, the major plant nutrients, and lesser or even trace amounts of other nutrients needed by different crops, such as boron, calcium, iron and zinc.

Until relatively recently, fertilizers were tested and certified for their nutrient content, but little attention was paid to the possibility of heavy metal contaminants introduced by the mineral sources used to prepare the fertilizer. However, in response to incidents of heavy metal contamination of cropland, several states have enacted regulations in the past seven years that limit the amounts of some potentially hazardous non-nutritive elements in fertilizers. Several countries, including Japan, China, and Australia, and the European Union, also limit the amount of selected elements in fertilizers.

While fertilizer manufacturers and state regulatory authorities have needed to develop analytical methods to implement these regulations, until now there have been no certified reference materials available that they could use to validate the accuracy of their measurements. It can be difficult to measure accurately trace levels of some metals in a chemically complex mixture like fertilizer.........

Posted by: Kevin      Permalink         Source

October 16, 2006, 10:14 PM CT

Harmful Algal Bloom Models

A new observation and modeling program focused on the southern Gulf of Maine and adjacent New England shelf waters could aid policymakers in deciding whether or not to re-open, develop, and manage offshore shellfish beds with potential sustained harvesting value of more than $50 million per year. These areas are presently closed to the harvest of certain species of shellfish due to the presence of red tide toxins.

Scientists at the Woods Hole Oceanographic Institution (WHOI) and his colleagues from seven other universities or agencies began the five-year Gulf of Maine Toxicity program, or GOMTOX, on September 1. The $7.5 million dollar program is funded by a grant from the National Oceanic and Atmospheric Administration's (NOAA) National Ocean Service, Center for Sponsored Coastal Ocean Research (NOS/CSCOR) through the ECOHAB program.

The new research effort expands past studies in the Gulf of Maine and builds on data collected during the historic 2005 red tide, which led to closure of both nearshore shellfish beds and offshore beds in federal waters out to Georges Bank. The toxicity also extended for the first time to the islands of Martha's Vineyard and Nantucket.

The Gulf of Maine (GoM) and its adjacent southern New England shelf is a vast region with extensive shellfish resources, large portions of which are frequently contaminated with paralytic shellfish poisoning (PSP) toxins produced by the dinoflagellate Alexandrium fundyense. The 2005 outbreak caused millions of dollars in economic damage, but monitoring programs and cooperation among federal, state and local officials, scientists, and shellfishermen prevented any reported cases of illness from people eating contaminated shellfish.........

Posted by: Tyler      Permalink         Source