Stories of modern science ... from UPI

By ELLEN BECK, United Press International  |  May 6, 2003 at 7:32 AM
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Researchers at Agriculture and Agri-Food Canada have devised a way to prevent the spread of genetically modified crops while allowing farmers to reseed the crops each year. A major concern is modified plants can interbreed with wild relatives or other related crop species. To prevent this the researchers inserted a gene for seed lethality into tobacco plants, which then grew normally but produced seeds that did not germinate. They also crossed the infertile plant with another engineered tobacco plant containing a gene that represses the seed lethality gene, creating a daughter generation with viable seeds that could theoretically be propagated repeatedly through self-pollination. When plants from that daughter generation were bred with wild-type tobacco plants, however, the SL gene and repressor gene were separated and seeds lacking the repressor gene failed to germinate.


Most treatment plants use chemical scrubbers and a environmentally hazardous caustic soda/bleach or peroxide combination to neutralize the rotten egg smell caused by hydrogen sulfide emissions. University of California Riverside scientists say biological filters can safely eliminate the odors. They packed polyurethane foam cubes covered with hydrogen sulfide-degrading bacteria into the scrubber and modified the pump and chemical supply systems. After the bacteria multiplied, the biotrickling filter proved just as efficient as chemical scrubbers, converting nearly 100 percent of the hydrogen sulfide into more innocuous sulfate. The bacteria also removed other pollutants, including ammonia and volatile organic compounds. The conversion cost approximately $50,000, but the researchers say the filters could save $30,000 a year in electricity and chemical costs.


The U.S. Department of Energy's Joint Genome Institute and Diversa Corp. are working to find and sequence microbial genomes found in unique habitats. Diversa will extract DNA from environmental samples and create gene libraries. JGI will do the DNA sequencing which will be deposited in GenBank for use by scientists around the world. "The microbial world is the next genomic frontier," said JGI Director Dr. Eddy Rubin. "The human genome has been sequenced, and now we're ready to tackle the larger and more complex challenge of sequencing microbial diversity." Microbes are the oldest life forms on Earth but more than 99 percent have not been cultured so their genomic diversity is unutilized. By studying the DNA, scientists hope to find ways to use microbes to develop new pharmaceutical and agricultural products, energy sources, industrial processes, and solutions to environmental problems.


On Wednesday the innermost planet in the solar system, Mercury, passes in front of the sun to produce a solar eclipse. The event could go by unnoticed as Mercury is so small that visually, it will barely be bigger than the point of a pencil. A powerful telescope is needed to observe the event. The disk of Mercury is only 13 arcseconds across, while the solar disk measures about 1,800 arcseconds -- like a coin located at the top of the Eiffel Tower as seen from the ground. These rare "Mercury Transits" -- when the planet is located directly between the Earth and the sun and also near one of two points in its orbit where Mercury's orbital plane intersects that of Earth -- occur about 13 times each century. The European Southern Observatory and the European Association for Astronomy Education are providing live images of the eclipse at


(EDITORS: For more information on GM CROPS, contact Johann P. Schernthaner at (613) 715-5397. For BIOLOGICAL FILTERS, Marc A. Deshusses, 64-3-364-2865, for SEQUENCING, Charles Osolin, (925) 296-5643 or, and for ECLIPSE, Richard West, 49-89-3200-6276 or

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