Skip To Content
NSF Logo Search GraphicGuide To Programs GraphicImage Library GraphicSite Map GraphicHelp GraphicPrivacy Policy Graphic
OLPA Header Graphic

News Tip


July 8, 2002

For more information on these science news and feature story tips, contact the public information officer listed at (703) 292-8070. Editor: Josh Chamot

New Evidence Found for "Oxidative Stress" Theory of Aging

Researchers have uncovered strong evidence for the long-held theory that the very oxygen we require to live is a contributor to aging, and antioxidant molecules can offset these effects.

The support for the "oxidative stress" model of aging comes from experiments that boosted fruit fly life spans in direct proportion to antioxidant production from manipulated genes. Researchers from the University of Southern California (USC) and University of California at Irvine reported their findings in the June 19 issue of the journal Genetics. The study was funded in part by NSF.

Many researchers believe that antioxidant substances such as vitamins C and E protect cells from the damaging effects of oxidation by neutralizing free-radicals - charged molecules that cells produce when they burn oxygen fuel. To test this theory directly, the researchers created fruit flies that had an extra copy of either of two antioxidant-producing genes known as superoxide dismutases, or SODs.

In control fruit flies, the researchers left the extra SOD genes inactive. Unsurprisingly, these flies lived a normal life span. In the experimental flies, the researchers activated the extra copy, causing the flies' cells to produce far more antioxidant enzymes than normal. These flies enjoyed a longevity boost of up to 40 percent, says lead researcher John Tower, a biologist at USC. And the magnitude of the boost was exactly proportional to the amount of extra SOD production, suggesting that the antioxidants were directly responsible, Tower says.

"It demonstrates that antioxidant activity is a rate-limiting factor for fly lifespan," he says. "There was no negative effect on metabolism from the SOD over-expression. So we're extending life span without some kind of trade-off or deficit in the creatures' metabolism," says Tower.

But now at least, says Tower, it's known that the beneficial effects of antioxidants occur when the genes are made to supply the substance. Drugs or gene therapy might some day be used to stimulate human cells to over-express SOD or similar genes, though it won't happen soon, he says. [Cheryl Dybas]

Top of Page

A Fish-Eye View of Management Through an Evolutionary Lens

Fishing, whether for business or pleasure, is regulated by agencies that impose size and catch limits on commonly exploited species. But the practice of selectively harvesting only the largest fish may be causing the average size of fish to decrease. David Conover, scientist at the Marine Sciences Research Center at Stony Brook University, reveals this finding in his paper "Sustaining Fisheries Yield over Evolutionary Time Scales," which appeared in the July 5 issue of Science.

Conover posits that fishery management plans ignore the possibility of evolutionary changes in harvestable fish populations. The researchers have observed such evolutionary trends in experimental fish populations. In a study jointly funded by NSF, NOAA, and the New York Sea Grant Program, Conover and his colleagues observed the Atlantic silverside (Menidia menidia), a small, common, marine fish. The researchers found that by removing large individuals, the average size in the population declined dramatically in just four generations. Conversely, when the smaller individuals were selected out, the average size increased.

Conover believes that fish harvesting has impacts beyond the immediate ecological response to changes in fish abundance. "Our study illustrates how well-intentioned management plans that appear to maximize yield on ecological time scales may have the opposite effect after accounting for evolutionary dynamics," reports Conover. Fishing may have evolutionary impacts that lead to genetic changes in the population that affect the growth rates of fish, and ultimately the productivity of harvested populations, he adds.

"More work is needed to determine whether or not evolutionary changes are occurring in wild populations," says Conover. But if so, the author suggests reevaluating our reliance on minimum size restriction as a basic management tool establishing no-take reserves or marine protected areas that may, if properly designed, maintain the natural genetic variation of marine life. [Cheryl Dybas]

Top of Page

NSF Accountability Reporting Lauded Twice

The Association of Government Accountants (AGA) will honor NSF again this year for the third consecutive year with its Certificate of Excellence in Accountability Reporting (CEAR), the AGA announced July 8. AGA established the certificate program in 1997 -- in conjunction with the Chief Financial Officers Council and the Office of Management and Budget -- to improve federal financial accountability. The award recognizes federal agencies for financial soundness and for excellent preparation, issuance and timeliness of their accountability reports. NSF is one of eight federal agencies so honored.

In an effort to meet accountability and performance reporting requirements while also communicating to the public in an engaging and meaningful way, NSF this year also developed a user-friendly brochure of management and performance highlights to complement the formal and statutory accountability report. This brochure was recognized by the League of American Communications Professionals (LACP) in its 2001 Annual Report Competition. LACP ranked it 4th overall in a competition of more than 600 entries. [Mary Hanson]

For NSF's Managment and Performance Highlights brochure, see:
For NSFs FY01 Accountability Report, see:
For more on AGA, see: http://AGACGFM.ORG/cear/index.htm
For more on LACP, see:

Top of Page



National Science Foundation
Office of Legislative and Public Affairs
4201 Wilson Boulevard
Arlington, Virginia 22230, USA
Tel: 703-292-8070
FIRS: 800-877-8339 | TDD: 703-292-5090

NSF Logo Graphic