Enhancement by methylated oxypurines of the frequency of induced chromosomal aberrations. IV. The dependence of the potentiation on the type of material.

Abstract

In Vicia faba, Allium proliferum and Nigella damascena root-tips, Cricetulus griseus and Potorous tridactylis cells an enhancement of the chromosome aberration frequency induced by Mitomycin C and Thiotepa was obtained in all materials after long post-treatments with 5 times 10-4 M caffeine, at various fixation times. In Vicia faba it was demonstrated that the most sensitive period for caffeine potentiation was 9–12 h after the beginning of the inducer treatment. This period corresponded to the middle-late S phase after Mitomycin C treatment in Vicia faba root-tips. Synergism was also evident after maleic hydrazide plus caffeine exposure in Vicia faba and Allium proliferum root-tips. The threshold value for caffeine potentiation after Mitomycin C was found to be the same for both Vicia faba root-tips and Chinese hamster cells (Cricetulus griseus), that is between 2–3 times 10-4 M. In all the materials, except Allium proliferum, the potentiation factor was higher for Thiotepa than Mitomycin C.