Effect of dimethyl sulfoxide (DMSO) on radiation-induced heteroallelic reversion in diploid yeast.

Dimethyl sulfoxide has cryoprotective and radioprotective properties. It is also an efficient scavenger of radicals produced by raiolysis of water. Gamma-induced reversions of diploid yeast in the presence of this chemical during irradiation have been studied. The dose-modifying factor was in the same range as for survival. When the yeast was irradiated in the frozen state the observed protection by DMSO disappeared. The results are discussed in terms of direct and indirect actions of radiations and the radical-scavenging ability of this chemical.