Lack of hypergravity-associated longevity extension in Drosophila melanogaster flies overexpressing hsp70

Previous studies have shown that Drosophila melanogaster males live longer if exposed to hypergravity at young age. Similarly, thermotolerance and climbing activity in old age are enhanced and it has been hypothetized that the 70 kDa inducible heat-shock protein (hsp70) may play a role in some of these effects. In this article, longevity, thermotolerance and climbing activity were studied in transgenic flies (OE+ strain) overexpressing hsp70 and in control flies harboring the transfection vector at the same chromosomal location but no extra-copies of the hsp70 gene (OE-strain). No positive effect from exposure to hypergravity at a young age was observed for longevity and climbing activity. Thermotolerance was increased by hypergravity but to the same extent in OE+ and OE-strains. Since no positive effect from hypergravity exposure or similar effects were observed in the two strains, it may be concluded that overexpression of hsp70 does not provide an advantage to flies subjected to a mild stress and that it may not be of any help during aging.