X-Message-Number: 21797 Date: Sat, 24 May 2003 12:21:12 -0700 (PDT) From: Doug Skrecky <> Subject: free radical theory of aging falsified [...in flies at least. Motor neuron degeneration is known to limit maximum fly longevity. By comparison cancer is the main limiting factor in rodents, but not in humans. (Only 4% of human centenarians die of cancer.) In humans atherosclerosis is the main limiting factor, with declines in immunity playing a secondary role. These two factors may be connected... There may exist no general theory of aging at all. Instead the nature of "aging" may vary for different species.)] J Biol Chem 2003 May 12; [epub ahead of print] Effects of overexpression of Cu-Zn and Mn superoxide dismutases, catalase and thioredoxin reductase genes on longevity in Drosophila melanogaster. The overexpression of antioxidative enzymes such as Cu-Zn superoxide dismutase (SOD), Mn SOD and catalase has previously been reported to extend life span in transgenic flies (Drosophila melanogaster). The purpose of the present study was to determine whether life-extending effects persist if the recipient control strains of flies are relatively long-lived. Accordingly, the life spans of large numbers of replicate control and overexpressor lines were determined in two long-lived genetic backgrounds, involving a combined total of more than 90 000 flies. Significant increases in the activities of both Cu-Zn SOD and catalase had no beneficial effect on survivorship in relatively long-lived y w mutant flies, and were associated with slightly decreased life spans in wild type flies of the Oregon-R strain. The introduction of additional transgenes encoding Mn SOD or thioredoxin reductase in the same genetic background also failed to cause life span extension. In conjunction with data from earlier studies, the results show that increasing the activities of these major antioxidative enzymes above wild type levels does not decrease the rate of aging in long-lived strains of Drosophila, although there may be some effect in relatively short-lived strains. Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=21797