Influence of RAS genes on yeast Saccharomyces cerevisiae cell viability in acid environment

  • Donaldas ČITAVIČIUS


During the yeast growth in SD medium (minimal medium with glucose), acidification of this medium can be observed. We determined that two RAS genes participate in both extracellular acidification and response to acid environment. In comparison with the wild-type SP1 strain, presence of the RAS2 gene deletion increases cell viability during gradual medium acidification as well as during acid stress induction. Increased cell viability causes a higher ΔRas2 strain growth rate and a higher medium acidification. The medium acidification rate of the strain containing deletion of RAS1 gene does not differ from SP1. However, cell viability during gradual acidification and in acid stress conditions is significantly higher as compared to SP1. These results suggest that RAS1 and RAS2 genes are negative regulators of cell viability in an acid environment, but their contribution to this regulation differs. Keywords: RAS genes, medium acidification, cell viability, acid stress