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Watching cholesterol - in worms and oysters.

Watching Cholesterol--in Worms and Oysters

Fewer pesky crop-attacking nematodes and more tasty oysters: A boost toward both goals may come from a new test to pinpoint sterols.

Nematodes cost U.S. farmers $7 billion a year in pesticides and damage to corn, soybeans, and other crops. But the test could speed efforts to find safer alternatives to current pesticides against nematodes, says zoologist David J. Chitwood, who devised the test.

The test more quickly and accurately pinpoints cholesterol and other sterols needed by nematodes--worms that live in soil and prey on roots. Needed by all plants and animals, sterols form chemical building blocks for fats and hormones.

"Nematodes convert sterols from plants into cholesterol and other forms that they need to grow on, make hormones, and reproduce," Chitwood says. "Safe compounds to short-circuit this conversion would be a boon to farmers."

Chitwood's test, which was developed at the ARS Nematology Laboratory in Beltsville, Maryland, is a modification of a method called reversed-phase high-pressure liquid chromatography. With fewer steps than present techniques, the new one takes as little as 30 minutes.

He used it to identify 28 sterols in the corn root lesion nematode, including 9 found for the first time in any nematode.

That's good sign compounds could be developed to thwart this worm's sterol pathways without harming anything else in the environment.

It's not underground pests but underwater treats that captivate a University of Maryland botanist. Glenn W. Patterson has adapted Chitwood's test to his studies of oysters. Patterson's objective is to learn which algae supply the best sources of sterols and other nutrients for oysters in the Chesapeake Bay.

While the mollusks get some sterols from green algae, they may get more from brownish to yellowish algae, called diatoms. "In some studies," he says, "big, healthy, fast-growing oysters had higher sterol levels than slow-growing oysters. We want to learn which sterols are most important in oysters and which algae--green ones or diatoms--best supply them. Then we'll have a scientific basis for knowing what improvements in the bay's water quality would best promote oyster growth."

David J. Chitwood is at the USDA-ARS Nematology Laboratory, Bldg. 467, BARC-East, 10300 Baltimore Ave., Beltsville, MD 20705-2350. Phone (301) 504-8634.
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Title Annotation:Agnotes
Author:De Quattro, Jim
Publication:Agricultural Research
Date:Jan 1, 1992
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