MICROGRAVITY EFFECTS ON DROSOPHILA-MELANOGASTER BEHAVIOR AND AGING - IMPLICATIONS OF THE IML-2 EXPERIMENT

Earlier Space experiments had indicated that young male Drosophila fli es exposed to microgravity showed an acceleration in aging. In a 14.5- day Space Shuttle Flight we sent 300 young male flies with the purpose of confirming these findings and to establish whether changes in the behavior of the flies were responsible for the effect in accordance wi th the proposal that alterations in mitochondrial metabolism may be in volved in the aging response. By repeatedly video-recording, we have f ound a very marked increase in the locomotor activity of the fruitflie s in Space. The males showed an accelerated aging response upon recove ry, both in terms of physiological vitality assays (mating and negativ e geotaxis) and of life-span curves. The involvement of mitochondrial metabolism is also suggested by the finding of a greater decrease in m itochondrial 16S ribosomal RNA in the microgravity exposed flies than in ground controls. On the other hand, a parallel 1 x g centrifuge con trol did not show such differences in the Life-span curves when compar ed to flies exposed to a similar centrifugation on the ground. Drosoph ila females also increased their locomotor activity but did not show d ifferential changes in the life-span curves. These results are discuss ed in terms of the current mechanisms of aging in multicellular eukary otic organisms.