try," says Simon R. Bare, an X-ray spectroscopist at UOP in Des Plaines, 111. "This is a significant accomplishment,, Certain radioactive isotopes, such as 55 Fe, 57Co, and 54Mn, undergo frequent electron-capture events and so are ideal for this method. For example, the authors are using it to study die mysterious oxidation states of manganese in a manganese-containing species—known as oxygen-evolving complex—that catalyzes the photosynthetic oxidation of water to dioxygen in algae and plants. Additionally, surface Fe in a catalyst could be labeled and studied. A spectrum can be obtained in about a day, Bergmann says. Bare, however, is concerned by that time length, as well as the cost and availability of the radioactive isotopes. Cramer says, however, that the group hopes to reduce the datagathering time to several hours. Elizabeth Wilson
Bt corn pollen kills monarch caterpillars
U.K. moratorium on biotech crops urged The British Medical Association (BMA) has called for a moratorium on the commercial planting of genetically modified (GM) crops until scientists agree on their long-term environmental effects. "Once the GM genie is out of the botde, the impact on the environment is likely to be irreversible," says Sir William Asscher, chairman of BMA's Board of Science & Education. "That is why the precautionary principle is so particularly important on this issue." About 112,000 physicians, or 80% of the doctors in the U.K., belong to BMA. The BMA report cites three possible dangers of genetically modified crops and food. First, antibiotic-resistant marker genes, which have been inserted into most such crops, could be transferred to microbes in human or animal guts and result in antibiotic-resistant microbes. Second, modified crops could cross-pollinate with wild species and create superweeds. This is more likely to happen in the U.K. than in the U.S., the group says, because farm fields in Britain are generally small and surrounded by hedgerows containing wild species. And, third, the effects of genetically modified crops on the ecosystem are not yet known. BMA also warns that "transgenic products may adversely affect people suffering from allergies" and says more research is needed on the allergenicity and possible toxicity of genetically modified foodstuffs. It calls for clear label-
Pollenfromcorn genetically engineered to produce a bacterial toxin that protects the plant against European corn borers kills monarch butterfly larvae in lab tests [Nature, 399,214 (1999)]. When Cornell University researchers sprinkled pollen from genetically engineered disturbed areas near corn"Bt-corn" onto milkfields, especially in the weed leaves and fed the Corn Belt, and as a weed leaves to monarch caterin cornfields, he says. Catpillars, nearly half the erpillars feed on milkweed caterpillars died. In the at the same time corn is same lab test, caterpilpollinating, so they are lars fed milkweed leaves likely to be exposed to the dusted with nontranstoxic pollen, which is the formed corn pollen all reason that they are conlived. Bt-corn is corn Monarch caterpillars on cerned about this probthat has been altered by pollen-dusted milkweed leaf. lem, Losey explains. the insertion of genes In Losey's experiment, from the bacterium Bacillus thuringiensis Bt pollen was dusted on milkweed at the (Bt) into its genes. First sold in 1996, Bt same concentration found on milkweed corn will be grown on about 22 million leaves in cornfields. The caterpillars that acres this year out of a total of 80 million fed on the Bt-pollen-dusted leaves ate less U.S. acres planted with corn. and grew more slowly than those in the Field research has shown that pollen control group and suffered a high mortalfrom corn travels as far as 60 yards from ity after four days. the edge of cornfields, says John E. LoHowever, "we can't predict how sesey, the Cornell entomologist who led rious the risk is until we have a lot the study. Milkweed, the exclusive food more data," Losey says. He is now conof monarch caterpillars, grows in the ducting a study in which large num-
ing of all such foods. And BMA says applications for permits to grow genetically modified crops should be subject to rigorous comprehensive risk assessments. Current assessments address only a few selected potential hazards, the group says. Alan Goldhammer, executive director for technical affairs for the Washington, D.C.-based Biotechnology Industry Organization, says the BMA report does not raise any solid issues. "Basically, what*s being added to the crops is DNA, which makes protein," he says. "We all have a pretty good handle on which proteins cause either toxicity problems or might be potential allergens." Sen. John Ashcroft (R-Mo.) believes BMA's study is mainly an effort to bolster protectionist trade policies. "Studies, such as this, when coupled with Europe's record of intransigent protectionism, demonstrate with absolute clarity why progress must begin with action by President Clinton to address biotech trade . . . at the upcoming G-8 summit,'' he says. Ashcroft is leading a bipartisan effort to convince the President and other world leaders to give top priority to expanding world trade in biotechnology. As C&EN went to press, the U.K. House of Commons' Science & Technology Committee weighed in with a report saying, "We have seen no evidence to suggest that the risks associated with growing GM crops and eating GM crops are high enough to justify calls that have been made for a moratorium." Bette Hileman
bers of volunteers are scouting out areas where milkweed is growing. The next step will be to measure the levels of pollen found on milkweed in the wild and compare them with those used in the lab study. An academic/industry initiative is now being set up to study the effects of Bt-corn pollen on monarch caterpillars in the field, says Randy Krotz, spokesman for Monsanto, a large producer of Bt-corn seed. The Biotechnology Industry Organization, Washington, D.C., notes that there are many other threats to monarch butterflies, including threats to its winter habitat in Mexico's central highlands and the use of chemical insecticides, which typically kill 100% of the caterpillars living near cropland. Losey believes that "we need to objectively weigh the risks versus the benefits of this new technology." Bette Hileman MAY 24,1999 C&EN
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