Respiratory mutant and liquid holding recovery inhibition in yeast cells

Background: Cell ability to recover from radia on damage is of great relevance in cancer treatment. It is o en believed that the inhibi on of cell ability to the liquid holding recovery (LHR) may be an indicator of the overall suppression of cell ability to recover from poten ally lethal radia on damage. However, the literature contains no experimental evidence whether the LHR inhibi on may always serve as marker of the significant increase in cell sensi vity to damaging agents. Materials and Methods: In experiments described here the yeast cells were used as a model for eukaryo c cells. The dose-response curves and recovery kine cs were determined by colony assay a er simultaneous treatment of heat with ionizing or UV radia ons as well as a er the simultaneous ac on of ionizing radia on and cispla n. The cell survival was es mated by both microscopic method and colony forming ability. Results: It is demonstrated that the recovery may take place on nutrient media. The complete inhibi on of cell recovery a er simultaneous heat treatment with ionizing radia on or UV light is accompanied with the significant increase in cell sensi vity to these agents, the actual increase being more appreciable than that expected a er the inhibi on of the LHR only. This rule is not universal as it was demonstrated for diploid yeast cells exposed to ionizing radia on and cispla n. Conclusion: The LHR takes place on nutrient media during the delay of the first pos rradia on division. The LHR inhibi on may not always indicate the suppression of other dark recovery processes and the corresponding increase in cell radiosensi vity.