EFFECTS OF HIGH-LET PARTICLES (A-40) ON BRAIN OF DROSOPHILA-MELANOGASTER

To investigate the effects of galactic heavy particles on nervous tissue, Drosophila melanogaster flies were exposed to 40A from the Super-HILAC accelerator at the Lawrence Berkeley Laboratory. The energy of the particles reaching the Drosophila neurons was 4.8 MeV/nucleon, and the fluence ranged from 6 .times. 104 to 8 .times. 107 particles/cm2. Thirty-five days after irradiation at the higher fluences, extensive tissue fragmentation and cysts were found. At fluences as low as 1 hit/2 cell bodies (about 5 .times. 106) and 1 hit/90 cell bodies (about 9 .times. 104 particles/cm2 or 21 rad average dose) swelling of neuronal cytoplasm and focally fragmented membranes were noted; at fluences ranging from 1 hit/6-1 hit/135 cell bodies, there was frequently a marked increase in glial lamellae around nerve-cell processes, which often had degenerative features. These findings support the view that single hits by heavy particles may injure nervous tissue.