Energy Metabolism in Yeast Cells after U.V.- and X-irradiation

Summary

Respiration, fermentation and fermentation under anaerobic conditions were measured in yeast cells exposed to moderate doses of U.V.- or X-radiation to yield colony-forming abilities between 100 and 1 per cent. Energy metabolism was followed for up to six hours. Since irradiated cells suffer a dose-dependent delay in division, the data were calculated in a per cell basis. It was found that energy metabolism always increased after low doses and declined after higher doses. For the case of U.V., partial photoreactivability indicates the involvement of nuclear factors. The results are interpreted in terms of radiation-induced disturbance of cellular regulation.