Differential "liquid holding recovery" for the lethal effect and cytoplasmic "petite" induction by UV light in Saccharomyces cerevisiae.

Abstract

Haploid and diploid wild types and UV-sensitive (uvs1–3) strains were exposed to UV light in stationnary phase of growth and in log phase. The liquid hold recovery (LHR) was studied in both conditions. 1. It appears that haploid wild type resting cells (1st type of repair) are less capable of repair during dark holding than dividing cells (2nd type of repair). 2. The mutant uvs1–3, which behaves like an excision defective strain, has lost the 1st type of repair. In contrast, the 2nd type of repair is still present. 3. The LHR is not additive to photorestoration (PR) for the 1st type of repair. On the contrary LHR and PR are additive for the 2nd type of repair. 4. Caffeine suppresses the 1st type of recovery and has only a slight effect on the 2nd type. 5. Both types of repair are functionning in diploid wild type cells where only the 2nd type of repair is present in UV-sensitive homozygous diploids uvs1/uvs1.