The relationship of the processes of recovery from thermal and radiation damage in yeast cells

Synergistic enhancement coefficient (SEC) achieves the maximum value within 2-3 hours of holding overheated (50 degrees C) and gamma-irradiated diploid cells of Sacch. cerevisiae in water at 28 degrees C; further holding leads to SEC dropping almost to the initial value. The maximum in the curve involved disappears if gamma-irradiated (overheated) cells were held in water at 28 degrees C for 2-3 hours before hyperthermic treatment (gamma-irradiation). There is no maximum in the curve discussed for haploid yeast cells, which are incapable of "rapid" post-irradiation recovering. The experimental data are interpreted from the point of view of reversible inhibition of yeast post-irradiation recovery by hyperthermia.