A Study of the Oxygen Effect and Radiosensitization of Hypoxic Cells by Metronidazole in Wild-type and Radiosensitive Mutants of Yeast

Summary

Radiosensitization of hypoxic yeast cells by oxygen and metronidazole was compared in wild-type and various X-ray radiosensitive mutants. The oxygen-enhancement ratio (o.e.r.) depended markedly on cell genotypes. Yeast strains which were deficient in ability to repair radiation damage had lower o.e.r. values than their more radioresistant parents. The relationship between o.e.r. and D_o was almost linear. Metronidazole was found to enhance radiosensitivity of hypoxic cells only of those strains that showed an o.e.r. more than 2·2. Some possible explanations of these effects are discussed.