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作者：dck 在 罕见奇谈 发贴, 来自 http://www.hjclub.org
USDA Backs Production of Rice With Human Genes
By Rick Weiss
Washington Post Staff Writer
Friday, March 2, 2007; A02
The Agriculture Department has given a preliminary green light for the first commercial production of a food crop engineered to contain human genes, reigniting fears that biomedically potent substances in high-tech plants could escape and turn up in other foods.
The plan, confirmed yesterday by the California biotechnology company leading the effort, calls for large-scale cultivation in Kansas of rice that produces human immune system proteins in its seeds.
The proteins are to be extracted for use as an anti-diarrhea medicine and might be added to health foods such as yogurt and granola bars.
"We can really help children with diarrhea get better faster. That is the idea," said Scott E. Deeter, president and chief executive of Sacramento-based Ventria Bioscience, emphasizing that a host of protections should keep the engineered plants and their seeds from escaping into surrounding fields.
But critics are assailing the effort, saying gene-altered plants inevitably migrate out of their home plots. In this case, they said, that could result in pharmacologically active proteins showing up in the food of unsuspecting consumers.
Although the proteins are not inherently dangerous, there would be little control over the doses people might get exposed to, and some might be allergic to the proteins, said Jane Rissler of the Union of Concerned Scientists, a science policy advocacy group.
"This is not a product that everyone would want to consume," Rissler said, adding that other companies grow such plants indoors or in vats. "It is unwise to produce drugs in plants outdoors."
Consumer advocacy groups, including Consumers Union and the Washington-based Center for Food Safety, have also opposed Ventria's plans. "We definitely have big concerns," said Joseph Mendelson, the center's legal director.
Ventria has developed three varieties of rice, each endowed with a different human gene that makes the plants produce one of three human proteins. Two of them -- lactoferrin and lysozyme -- are bacteria-fighting compounds found in breast milk and saliva.
A recent company-sponsored study done in Peru concluded that children with severe diarrhea recovered a day and a half faster if the salty fluids they were prescribed were spiked with the proteins.
Deeter said production in plants is far cheaper than other methods, which should help make the therapy affordable in the developing world, where severe diarrhea kills 2 million children each year.
"Plants are phenomenal factories," Deeter said. "Our raw materials are the sun, soil and water."
The company is also talking to the Food and Drug Administration about putting the proteins into health foods. Its third variety of rice makes serum albumin, a blood protein used in medical therapies.
Until now, plants with human genes have been restricted to small test plots. In October, Ventria sought permission to grow its rice commercially on as many as 3,200 acres in Geary County, Kan., starting with 450 acres this spring.
A previous plan to grow the rice in southern Missouri was dropped when beermaker Anheuser-Busch -- the nation's largest rice buyer, which has expressed concern about the safety and consumer acceptance of gene-altered rice -- threatened to stop buying rice from the state if the deal went through.
Because no other rice is grown in Kansas and because rice can only grow in flooded areas, the risk of escape or cross-fertilization with other rice plants is nil there, Deeter said. The company will mill virtually all the seeds on site -- using dedicated equipment -- to minimize the risk of seeds getting mistakenly released or sold.
On Wednesday, the Agriculture Department published its draft environmental assessment, which concluded that the project posed no undue risks. The public can comment until March 30.
Also on Wednesday, the agency revealed that a type of rice seed in Arkansas had become contaminated with a different variety of genetically engineered rice, LL62, that was never released for marketing. The error was discovered in the course of an ongoing investigation into the widespread contamination of U.S. rice by yet another gene-altered variety, LL601, which has seriously disrupted rice exports.
Those problems, along with the previous discovery of unapproved, gene-altered StarLink corn in food and the accidental release of crops that had been engineered to make a vaccine for pig diarrhea, undermine the USDA's credibility, critics said.
"USDA's record is not good," Rissler said, pointing to several recent court judgments against the department and a December 2005 inspector general report that savaged the department for its poor oversight of biotechnology. "We don't think they can enforce even the inadequate system that is in place."
作者：dck 在 罕见奇谈 发贴, 来自 http://www.hjclub.org |
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