Sci. Aging Knowl. Environ., 31 October 2001
Bye-bye Birdie: Short-lived fryers less resistant to molecular pecking than long-lived fliers
R. John Davenporthttp://sageke.sciencemag.org/cgi/content/abstract/sageke;2001/5/nw17
Key Words: bird budgerigar budgie quail mouse human oxidative damage oxygen hydrogen peroxide
Abstract: Our feathered friends might be hiding a few antiaging tricks under their wings: New results suggest that long-lived birds withstand damage caused by reactive oxygen molecules better than either mammals or short-lived birds do.
Pound for pound, birds survive much longer than do mammals, but they also break down food for energy at higher rates. Those observations seem paradoxical because metabolic activity produces reactive oxygen species (ROS)--destructive molecules that likely contribute to aging (see "The Two Faces of Oxygen"). Recent studies indicate, however, that compared to mammals, long-lived birds produce fewer ROS per molecule of oxygen processed. And those birds also appear more adept at preventing ROS from causing cellular damage. But no one had established whether all birds or only long-lived ones carry these traits.
To investigate this issue, Ogburn and colleagues cultured cells from two species of birds: quail, which live about 4 years, and budgerigars (common pets fondly known as budgies), whose longevity can top 20 years. They also tested short- and long-lived mammals: mice, with a life-span of 3 years, and humans, who can survive to ages greater than 100. The researchers subjected the cell cultures to oxidative stress by exposing them to high concentrations of oxygen or hydrogen peroxide, and then they counted the cells that persisted. A higher percentage of budgie cells survived the assault than did those from the other three species. Additional experiments indicate that the budgies' superior defenses require active genes: When the researchers added chemical inhibitors of either messenger RNA or protein synthesis to the cells, budgie cell survival after treatment dropped to the level measured in the other three species. The results indicate that long-lived birds fend off oxidative damage better than do their less-robust cousins.
It's unclear if the cell culture model accurately reflects the response of cells in vivo. But the system does give scientists a controlled way to compare species and flush out budgies' possible secrets to a longer life. Budgies could boast a greater quantity of the same antioxidant enzymes that shorter-lived species employ, or they might have developed unique strategies for dealing with oxidative injury. Pinpointing the genes responsible for the difference between species might reveal the answer. Such information could enhance our understanding of possible connections between oxidative damage and aging and hint at ways to give wings to our own defenses.
--R. John Davenport
C. E. Ogburn, K. Carlberg, M. A. Ottinger, D. J. Holmes, G. M. Martin, S. N. Austad, Exceptional Cellular Resistance to Oxidative Damage in Long-Lived Birds Requires Active Gene Expression. J. Gerontol. A Biol. Sci. Med. Sci. 56, B468-B474 (2001). [Abstract] [Full Text]
Citation: R. J. Davenport, Bye-bye Birdie: Short-lived fryers less resistant to molecular pecking than long-lived fliers. Science's SAGE KE (31 October 2001), http://sageke.sciencemag.org/cgi/content/abstract/sageke;2001/5/nw17
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