engleski

Morphological and physiological characteristics of the yeast Saccharomyces cerevisiae cells differing in the life span

S. cerevisiae has a special place among the model organisms currently in use for aging research. During their replicative lifespan yeast cells undergo age-related changes. The aim of this study was to observe morphological and physiological characteristics of the yeast S. cerevisiae cells during its replicative life span. Three different genetic background were analyzed (SP4, BY4741 and BMA64-1A), each consisting of a wild-type strain and its isogenic mutant (Δfob1 and Δsod1). Relative growth and rate of glucose consumption was determined as well as sensitivity to oxidative stress. Detection of the ROS was performed using dihydroethidium assay, while with the immunocytochemistry assay was determined the presence of protein carbonyl groups. Samples were also cultivated for 7 days, during which cellular alternations and metabolic activity were determined, both by corresponding fluorescence techniques. To interpret parametric results, ANOVA statistical tests were used. Results of experiments have shown that there is no significant difference in replicative life span between SP4 and BY4741 cells, whereas BMA64-1A cells showed higher sensitivity to growth conditions. Wild-type and Δfob1 strains of each genetic background demonstrated similar results in all experiments, showing the lower sensitivity to environmental conditions during the life span contrary to Δsod1 mutant. According to the hypothesis that reaching excessive volume by yeast cells limits their ability to undergo further reproduction resulting in cell senescence, stationary cells showed higher cell size than cells at exponential growth phase.

aging, yeast, S. cereviaise, life span, replicative life span

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