MODIFICATION OF GENOTOXICITY OF RADIATION BY POSTIRRADIATION TREATMENT WITH CAFFEINE

The effect of caffeine during post-irradiation growth period on surviv al, gene conversion, back mutation, aberrant colony formation (ACF) an d mitotic crossing over (MCO) was investigated in the diploid yeast st rain Saccharomyces cerevisiae D7. The presence of caffeine in growth m edia reduced the radiation-induced cell killing and the frequency of a ll the genetic end points except MCO. The increase in MCO frequency mi ght be related to the enhanced cell survival brought about by caffeine . It is suggested that post-irradiation division delay introduced by c affeine may alter the post-irradiation repair processes and may help t he process of recovery by error-free repair pathways.