Bailiak M. Enhancement of the adaptive capacity of the yeast Saccharomyces cerevisiae and the fruit fly Drosophila melanogaster by using plant extracts, keto acids, and arginine

The dissertation is devoted to the study of stress-protective and geroprotective properties of plant derived substances (quercetin and Rhodiola rosea extracts), as well as cellular metabolites, alpha-ketoglutarate and arginine. In vitro experiments and experiments with model organisms, yeast S. cerevisiae and fruit fly D. melanogaster, showed, that depending on the conditions, the studied natural factors could act as antioxidants and prooxidants. The antioxidant activity of the plant extracts was higher at low pHs, whereas the prooxidant activity was higher at alkaline pHs. The aqueous extract from R. rosea root showed adaptogenic and geroprotective effects in S. cerevisiae in a concentration-dependent manner. The adaptogenic action of R. rosea required the presence of Msn2/4 and Yap1 transcription factors, and the protective action of quercetin required only Msn2/Msn4 proteins. Exogenous alpha-keroglutarate has stress-protective and geroprotective effects in S. cerevisiae and D. melanogaster via affecting amino acid metabolism and stimulation of antioxidant defense. Dietary arginine had beneficial effects on larval development and metabolism of young D. melanogaster adults, but long-term consumption of arginine-supplemented food decreased fecundity and lifespan of flies.