Effect of single and fractionated doses of gamma radiation on pupariation of housefly.

Abstract

Larvae of different ages from 40 hr to 72 hr were exposed to γ-rays ranging between 500R and 10000R ; all ages of the larvae showed dose-dependence pupariation delay up to 4000R. The shape of the puparia were not normal in the larvae irradiated with higher doses. Sparing effect of dose fractionation (SDF) was demonstrated for the pupariation delay. Sparing effect was quite marked at low dose-rate (15R/second) than at high dose-rate (80R/second) and maximum SDF was found with 2 hr interfraction interval as compared to 4.5 and 6.5 hr. The magnitude of SDF was comparatively less at 15°C than at 35°C indicating the occurrence of repair. Furthermore, the metabolic requirement of repair processes was evidenced by the abolition of SDF by inhibitors of energy metabolism, DNA binding agents and protein synthesis inhibitors.