September 2, 1997
ARS News Service
Agricultural Research Service, USDA
Jim De Quattro
(301) 344-2756
[email protected]
1. Do Children's Growth Standards Need Refinement?
A new study adds to previous evidence that children's body composition standards may need a closer look to make sure they reflect the ethnic diversity of American teenagers. Growth standards currently refer only to age, gender and weight. The new study is the latest evidence that including body composition--the ratio of fat, bone and lean muscle--might help assess more accurately whether a child is growing up healthy.
The study--of 297 healthy white, black and Hispanic boys ages 3 to 18--was done in Houston at the Children's Nutrition Research Center. The center is a cooperative facility of USDA's Agricultural Research Service (ARS) and Baylor College of Medicine.
Preliminary findings suggest black, white and Hispanic boys develop differences in body composition as they reach puberty. Among the three groups, the black teens stored relatively more muscle and bone, and Hispanic teens stored relatively more fat. An earlier study--of girls--at the center also suggested considering ethnic diversity in body composition standards.
Scientific contact: Kenneth J. Ellis, USDA-ARS/Baylor College of Medicine, Body Composition Laboratory, Children's Nutrition Research Center, Houston, Texas, phone (713) 798-7131, fax 798-7130, [email protected]
2. Eastern Gamagrass Surviving Drought
Green patches in a brown field are making researchers smile in Beltsville, Md. The green is eastern gamagrass. A native species, it was grazed into near-oblivion decades ago, but rediscovered during a 1980 drought. This "new old grass," a perennial that grows as high as its relative corn, is again surviving severe drought at ARS' Beltsville (Md.) Agricultural Research Center. Nearby corn is parched: about an inch of rain fell from the first of July to mid-August. But gamagrass has been cut twice, yielding 6,600 pounds of 14-percent-protein hay per acre, on par with alfalfa.
Eastern gamagrass gets its edge against drought from air-filled root passages called aerenchyma [pronounced air-ENK-a-ma]. With aerenchyma, roots penetrate so deep they draw water shallow-rooted plants can't touch. Researchers plan further studies to see if eastern gamagrass' deep roots can loosen compacted soils and provide channels for roots of other crops. They also want to test the grass in buffer strips to reduce soil erosion.
To see a photo of Beltsville's eastern gamagrass on the World Wide Web, point your browser to http://www.ars.usda.gov/is/graphics/photos/k7820-6.htm. A feature story on aerenchyma research, from the August issue of Agricultural Research magazine, is at http://www.ars.usda.gov/is/pr/aerenchyma0897.htm.
Scientific contacts: ARS Climate Stress Laboratory, Beltsville, Md. Donald Krizek, phone (301) 504-5324, fax 504-6626, [email protected]; and Charles Foy, phone (301) 504-5522, fax 504-7521.
3. Squeezing Fat Out of Foods
It sounds like a dieter's dream: finding a way to squeeze the fat out of foods we love, like big juicy hamburgers. ARS scientists have developed a way to do just that--not for counting calories, but for food analysis--while reducing the steps and chemical solvents now used to analyze foods' fat content for nutritional labeling.
By teaming a technology called supercritical fluid extraction with an enzyme called lipase, the scientists can simultaneously extract fat from hamburger samples and complete the chemical reaction needed to release the fats. In conventional fat analysis, the sample must first be treated with chemical solvent, and more chemicals are required to extract the fat.
Scientific contact: Janet M. Snyder, USDA-ARS Food Quality and Safety Laboratory, NCAUR, Peoria, Ill.; phone 309-681-6236, [email protected].
4. Smoking Out Bee Mites
Calming bees with smoke is a long-established beekeeping practice. Now scientists have found that smoke from burning certain plants contains natural chemicals that control honey bee mites. It may have potential as an alternative to using chemicals to control varroa mites, the domestic honey bee's worst threat.
Frank Eischen with ARS in Weslaco, Texas, has tested smoke from 40 different plants to control varroa mites. The most promising are dried grapefruit leaves and creosote bush, a woody perennial. Creosote bush smoke drove 90 to 100 percent of the mites off bees after a one-minute cage test. Grapefruit leaf smoke drove off 90 to 95 percent of the mites in 30 seconds. More research is needed before scientists could recommend that beekeepers use these plant smokes to control mites.
The standard treatment for the mites is fluvalinate, a synthetic pyrethroid. Beekeepers put fluvalinate-impregnated strips in their hives to kill mites. But they can only use the strips when bees are not collecting nectar and pollen.
A story on the research can be found on the World Wide Web at: http://www.ars.usda.gov/is/pr/mitesmoke0897.htm
Scientific contact: Frank Eischen, ARS Honey Bee Research Lab, Weslaco, Texas, phone (956) 969-5007, fax (956) 969-5033, [email protected]
5. Mouth-Watering New Fruits
Flavorful new peaches and nectarines from California should please growers and shoppers alike. The treefruits are the latest from ARS' Horticultural Crops Research Laboratory in Fresno, where scientists have produced 26 flavorful new fruits in the past 25 years.
The lab's most recent varieties include Spring Baby, Spring Gem and Autumn Red peaches, and Crimson Baby and September Free nectarines. Cuttings of the new fruits are available to growers. Consumers may begin seeing them at markets in about 5 years.
"Embryo rescue" techniques perfected by the Fresno scientists enable them to produce fruits that ripen earlier in spring than before. Embryos from early-season parents are usually too small to survive on their own, so researchers rescue them from the developing stone, or pit. In the lab, the embryos thrive on a gel-like bed of nutrients until they grow into plants.
The August issue of the agency's magazine Agricultural Research carries an in-depth article on the new fruits. The story also is on the World Wide Web at: http://www.ars.usda.gov/is/pr/fruit0897.htm
Scientific contact: David W. Ramming, USDA-ARS Horticultural Crops Research Laboratory, Fresno, Calif., phone (209) 453-3061, fax (209) 453-3088, [email protected]
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