EFFECT OF LOW-TEMPERATURE ON RADIATION-INDUCED GENETIC-DAMAGE IN DROSOPHILA-MELANOGASTER - RESPONSE OF MOTILE SPERM AND LATE SPERMATIDS

The response of fully mature motile sperm and late spermatids when challenged with X-radiation at 0-degrees-C has been studied in sex-linked recessive lethals, II-III translocations and dominant lethality experiments. At 0-degrees-C a significant increase in both mutagenic and clastogenic damage was detected compared to that obtained at 24-degrees-C. Furthermore, the results of experiments performed with different postirradiation temperatures demonstrate that the low temperature during irradiation was the sole factor responsible for the observed increase. In the recessive lethal and translocation tests the response of late spermatids was higher than that shown by motile spermatozoa. As a whole, the results, which are rather similar to data reported on the effect of irradiation in oxygen of the same cell stages, suggest that the low temperature acted as a dose-modifying factor.