September 14, 2006, 6:15 PM CT
Mechanisms of Sudden Oak Death
California Bay Laurel leaves infected with Phytophthora ramorum
By comparing the complete genome sequences of two plant-killing pathogens and related organisms, scientists from the U.S. Department of Energy Joint Genome Institute (DOE JGI), in collaboration with the Virginia Bioinformatics Institute (VBI) and others, have uncovered crucial aspects of the disease-causing mechanisms of "Sudden Oak Death" (SOD) and soybean root rot disease. The research, the result of a four-year, $4 million multi-agency project supported by DOE, U.S. Department of Agriculture (USDA), and the National Science Foundation (NSF), appears in the Sept. 1, 2006, edition of Science (vol. 313, No. 5791).
"This project best exemplifies how the capabilities that were established at the DOE JGI for sequencing the human genome are now proving to be essential for addressing important environmental challenges," said Eddy Rubin, DOE JGI Director. "We are now capable of rapidly responding to the urgent needs of the nation's largest industry, agriculture, where genome sequence information can be brought to bear on characterizing such economically important microorganisms as those that cause sudden oak death and soybean root rot. For these pathogens, the genome sequence is the wiring diagram of the cellular processes that can be targeted for novel detection systems and for safe and effective means of control".........
Posted by: Erica Permalink Source
September 14, 2006, 6:10 PM CT
The First Tree Genome is Published
Wood from a common tree may one day factor prominently in meeting transportation fuel needs, as per researchers whose research on the fast-growing poplar tree is featured on the cover of tomorrow's edition of the journal Science.
The article, highlighting the analysis of the first complete DNA sequence of a tree, the black cottonwood or Populus trichocarpa, lays the groundwork that may lead to the development of trees as an ideal "feedstock" for a new generation of biofuels such as cellulosic ethanol. The research is the result of a four-year scientific and technical effort, led by the U.S. Department of Energy's Joint Genome Institute (DOE JGI) and Oak Ridge National Laboratory (ORNL), uniting the efforts of 34 institutions from around the world, including the University of British Columbia, and Genome Canada; Umeå Plant Science Centre, Sweden; and Ghent University, Belgium.
"Biofuels could provide a major answer to our energy needs by giving the United States a homegrown, environmentally friendlier alternative to imported oil," said DOE's Under Secretary for Science Dr. Raymond L. Orbach. "Fine-tuning plants for biofuels production is one of the keys to making biofuels economically viable and cost-effective. This research, employing the latest genomic technologies, is an important step on the road to developing practical, biologically-based substitutes for gasoline and other fossil fuels."........
Posted by: Janet Permalink Source
September 14, 2006, 4:31 AM CT
Warming might affect polar bear population
Some travel agencies touting Arctic tours have been revving up their recent promotions to tourists about the increased likelihood they will spot polar bears in this region where several populations of polar bears live. According to scientists from NASA and the Canadian Wildlife Service, these increased Arctic polar bear sightings are probably related to retreating sea ice triggered by climate warming and not due to population increases as some may believe.
The new research suggests that progressively earlier breakup of the Arctic sea ice, stimulated by climate warming, shortens the spring hunting season for female polar bears in Western Hudson Bay and is likely responsible for the continuing fall in the average weight of these bears. As females become lighter, their ability to reproduce and the survival of their young decline. Also, as the bears become thinner, they are more likely to push into human settlements for food, giving the impression that the population is increasing. The study will be published this week in the recent issue of the Journal Arctic.
Claire Parkinson, a scientist at NASA's Goddard Space Flight Center, Greenbelt, Md., and Ian Stirling, a senior scientist with the Canadian Wildlife Service, Edmonton, Alberta, used NASA satellite observations captured from 1979 to 2004 to show the reduction in sea ice cover in several specific areas where there are known polar bear populations. In most of the areas studied, they found that ice break-up in these areas has been occurring progressively earlier.........
Posted by: Kelly Permalink Source
September 13, 2006, 9:52 PM CT
Arctic Sea Ice Diminishing Rapidly
The Arctic Ocean's perennial sea ice, which survives the summer melt season and remains year-round, shrank abruptly by 14 percent between 2004 and 2005, as per a newly published study. Scientists observed that the loss of perennial ice in the East Arctic Ocean, above Europe and Asia, neared 50 percent during that time as some of the ice moved to the West Arctic Ocean, above North America.
The overall decrease in winter Arctic perennial sea ice totaled 730,000 square kilometers [280,000 square miles]--an area the size of Texas. Perennial ice can be three meters [10 feet] thick, or more. It was replaced in the winter by new, seasonal ice, which was only about 0.3 to two meters [one to seven feet] thick and more vulnerable to summer melt. The research was published 7 September in the journal Geophysical Research Letters.
The decrease in perennial ice raises the possibility that Arctic sea ice will retreat to another record low extent this year. This follows four summers of very low ice-cover, as observed by active and passive microwave instruments.
A team of seven scientists, led by Son Nghiem of NASA's Jet Propulsion Laboratory in Pasadena, California, used satellite data to measure the extent and distribution of perennial and seasonal sea ice in the Arctic. While the total area of all Arctic sea ice was stable in winter, the distribution of seasonal and perennial sea ice changed significantly.........
Posted by: Janet Permalink Source
September 13, 2006, 9:17 PM CT
The Machinery Of Cellular Protein Factories
Proteins of all sizes and shapes do most of the work in living cells, and the DNA sequences in genes spell out the instructions for making those proteins. The crucial job of reading the genetic instructions and synthesizing the specified proteins is carried out by ribosomes, tiny protein factories humming away inside the cells of all living things.
Harry Noller, the Sinsheimer Professor of Molecular Biology at the University of California, Santa Cruz, has been studying the ribosome for more than 30 years. His main goal is to understand how the ribosome works and how it evolved, but there are also practical reasons to pursue this research. A number of of the most effective antibiotics work by targeting bacterial ribosomes, and findings by Noller and others have led to the development of novel antibiotics that hold promise for use against germs that have developed resistance to current drugs. Drug-resistant staph infections, for example, are a serious problem in hospitals.
Noller's laboratory achieved breakthroughs in 1999 and 2001, producing the first high-resolution images of the molecular structure of a complete ribosome. Now, his team has made another major advance with an even higher-resolution image that enables them to construct an atom-by-atom model of the ribosome.........
Posted by: Janet Permalink Source
September 13, 2006, 9:14 PM CT
Expedition to polar research
What better way to engage students in science than to apply lessons learned from fieldwork? This is the philosophy of Alaska teachers participating in the Arctic Expedition for K-12 Teachers, a program organized by the International Arctic Research Center (IARC) at the University of Alaska Fairbanks and a handful of international agencies.
For 33 days teachers from Alaska, Canada, France, Germany, Russia, Sweden and England will take atmospheric measurements, collect ice cores, install ice mass balance sensors and more, all under the guidance of an international team of polar researchers. Teachers and scientists will work together to collect data. Their work is based on the Kapitan Dranitsyn, an icebreaker currently cruising through the Arctic Ocean.
Todd Hindman, a teacher from Nome City School District, said This will give my students an opportunity to learn about the environment they live in, which will engage them in a meaningful way both inside and outside of the traditional classroom walls.
The experience will enhance my teaching by increasing my understanding of ocean systems, said Katie Turner, a science teacher at West Anchorage High School. It will give me real world experience and knowledge to share with my students.
The expedition advances scientists work in the fields of meteorology, biology, chemistry and oceanography. Five IARC scientists are aboard the Kapitan Dranitsyn, too, as part of the Nansen and Amundsen Basins Observational System (NABOS). Their aim is to better understand a flow of anomalous warm Atlantic water entering the Arctic Ocean. Preliminary data suggests this infusion of water from the Atlantic is increasing the temperature of the Arctic waters.........
Posted by: Kelly Permalink Source
September 13, 2006, 5:14 AM CT
Greener Path To Iron Production
MIT engineers have demonstrated an eco-friendly way to make iron that eliminates the greenhouse gases commonly linked to its production.
The American Iron and Steel Institute (AISI) announced recently that the team, led by Donald R. Sadoway of the Department of Materials Science and Engineering, has shown the technical viability of producing iron by molten oxide electrolysis (MOE).
"What sets molten oxide electrolysis apart from other metal-producing technologies is that it is totally carbon-free and hence generates no carbon dioxide gases -- only oxygen," said Lawrence W. Kavanagh, AISI vice president of manufacturing and technology.
The work was funded by the AISI/Department of Energy Technology Roadmap Program (TRP). The TRP goal is to increase the competitiveness of the U.S. steel industry while saving energy and enhancing the environment. As per the AISI, the MIT work "marks one of TRP's breakthrough projects toward meeting that goal".
Unlike other iron-making processes, MOE works by passing an electric current through a liquid solution of iron oxide. The iron oxide then breaks down into liquid iron and oxygen gas, allowing oxygen to be the main byproduct of the process.
Electrolysis itself is nothing new -- all of the world's aluminum is produced this way. And that is one advantage of the new process: It is based on a technology that metallurgists are already familiar with. Unlike aluminum smelting, however, MOE is carbon-free.........
Posted by: Erica Permalink Source
September 13, 2006, 5:10 AM CT
Do green markets actually lead to improvements in environmental quality?
Goods and services with environmental benefits are a growing part of a number of sectors of the economy, and a timely new paper from the current issue of the Journal of Political Economy analyzes how our willingness to pay more for environmentally friendly products actually influences environmental quality and social welfare. Surprisingly, the study finds that under certain reasonable conditions, green markets can actually discourage private support of public environmental entities.
Using a model of impure public goods, Matthew J. Kotchen (University of California, Santa Barbara) analyzes goods that have both private and public components, each of which is available individually. For example, shade-grown coffee is grown not on deforested plantations, but under the canopy of tropical forests. Thus, consumers are not only buying coffee, which is a traditional private good, but also biodiversity conservation. However, consumers also have the option to buy conventional coffee and donate directly to tropical conservation.
"Eventhough green markets are promoted to improve environmental quality and promote social welfare, their actual effects may be detrimental to both," writes Kotchen. "These results, along with the conditions sufficient to rule them out, provide new insight into the potential advantages and disadvantages of green markets as a decentralized mechanism of environmental policy".........
Posted by: Erica Permalink Source
September 13, 2006, 4:50 AM CT
Plastic Replicas Of Real Cells
Real or replica?
Call them genuine fakes. Brown University biomedical engineer Diane Hoffman-Kim and her research team have made plastic replicas of real cells through a novel two-part molding process. The copies looked so authentic, Hoffman-Kim couldn't tell if they were real or rubber at first.
"When I saw the images from the microscope, I said, 'OK, I can't tell the difference,'" Hoffman-Kim said. "It was pretty amazing - and just what we wanted".
A description of the replicas, their ability to support cell growth, and their possible applications in science and medicine are published in Langmuir, a journal of the American Chemical Society.
The main cells used in the experiments were Schwann cells, which protect peripheral nerves by wrapping around their axons to create insulating myelin sheaths. Schwann cells also direct axon growth during cell development and repair.
Hoffman-Kim, an assistant professor in the Department of Molecular Pharmacology, Physiology and Biotechnology and the Division of Engineering, said the realistic replicas could be used in laboratories to help scientists understand how these critical support cells sustain and direct nerve growth.
The replicas could also, eventually, be used in hospitals to help doctors regenerate nerves. If a patient's nerves are severed during an auto accident or other injury, a device coated with the imitation cells - a contraption called a nerve guidance channel - could be implanted into the injured area to help stimulate nerve growth and repair damaged tissue. Tissue engineers around the world are testing nerve guidance channels in animals and, in a few cases, in humans.........
Posted by: Janet Permalink Source
September 11, 2006, 8:15 PM CT
Sheep Need Virus for Reproduction
A team of researchers from Texas A&M University and The University of Glasgow Veterinary School in Scotland has discovered that naturally occurring endogenous retroviruses are mandatory for pregnancy in sheep.
In particular, a class of endogenous retroviruses, known as endogenous retroviruses correlation to Jaagsiekte sheep retrovirus or enJSRVs, are critical during the early phase of pregnancy when the placenta begins to develop.
Retroviruses, such as human immunodeficiency virus or HIV, are one class of viruses. They are best known for their ability to cause diseases, said Dr. Thomas Spencer, a reproductive biologist with the Texas Agricultural Experiment Station and Texas A&M University.
Findings published Sept. 11 in the Proceedings of the National Academy of Sciences demonstrate enJSRVs are essential for the development of the placenta in sheep.
Retroviruses are unique for their ability to permanently insert their genetic material into the DNA of host cells, he said. During evolution of mammals, some retroviruses infected the germline (cells of the ovary and testis that have genetic material that are passed to their offspring) of the host, which is then inherited by their children. These retroviruses, known as endogenous retroviruses, are present in the genome of all mammals, including humans. Consequently, endogenous retroviruses can be considered remnants of ancient retroviral infections, Spencer said.........
Posted by: Kelly Permalink Source
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