Biological damage in the mature sperm of Drosophila virilis in oxygen and nitrogen with different dose intensities of gamma rays.

Abstract

Modifications in the percentages of dominant lethal and translocation damage were not obtained by varying the dose rate of gamma rays in treatments of mature sperm of Drosophila virilis. Nineteen experiments in five series of tests were perforraed using radiation dose rates from 50 to 2000 r/minute or two fractionated doses divided by periods of from 15 to 60 minutes. The dose rates of gamma rays did not modify the amount of two break, reattachment types of chromosome damage, translocations, or dominant lethal damage when treatments were made in either a completely oxygen-saturated atmosphere or an anoxic atmosphere of nitrogen. Postirradiation recovery periods were not detected by testing with alternate radiation treatments in oxygen and nitrogen. Different time intervals of 15 to 40 minutes between treatments failed to produce modifications in the percentages of dominant lethals. Therefore, there is no indication of a postirradiation time limit for recovery mechanisms in Drosophila sperm. ln all the radiation tests using mature sperm of Drosophila virilis, the genetic damage was characterized by the induction of genetic damage which was not modified by the dose rate tested in external enviroments of oxygen or anoxic atmospheres of gases. The possibility of genetic repair mechanisms operatingmore » after chronic doses of radiations of spermatogonial cells and postirradiation effects in raetabolically active cells are discussed briefly. (auth)« less