Effects of Cu-Zn Superoxide Dismutase Overexpression on Life Span and Resistance to Oxidative Stress in Transgenic Drosophila melanogaster

Reactive oxygen species have been postulated to be a causal factor in the aging process due to their ability to inflict molecular damage. The role of the enzyme copper-zinc superoxide dismutase (Cu-Zn SOD; superoxide:superoxide oxidoreductase; EC 1.15.1.1), which scavenges superoxide anion radicals, as a longevity determinant was examined in transgenic Drosophila melanogaster. A genomic fragment containing the Drosophila Cu-Zn SOD gene was introduced into the germ cells via a P element containing Casper vector. In different transgenic lines, overexpression of SOD by 32-42% above normal had either a minor and/or an insignificant effect on life span of the flies and their ability to withstand experimental oxidative stress, induced by paraquat intake and exposure to hyperoxia (100% oxygen). Transgenics showing a small increase in mean life span also exhibited a corresponding improvement in their resistance to byperoxia but not paraquat. The maximum life span of populations was not affected.