[Role of trehalose and glycogen in the survival of aging Saccharomyces cerevisiae cells]. / Rol' tregalozy i glikogena v podderzhanii zhiznesposobnosti stareiushchikh kletok Saccharomyces cerevisiae.

The role of the storage carbohydrates trehalose and glycogen in the survival of aging Saccharomyces cerevisiae cells was studied. Culture aging for one week did not reduce cell viability. During this period, the cells accumulated the storage carbohydrates and raised the activity of the glycolytic enzymes hexokinase and phosphofructokinase. However, further aging led to a drastic drop in cell viability and to a decrease in the cellular content of trehalose and glycogen and in the activity of hexokinase and phosphofructokinase. The possible reasons for these changes are discussed.

[Effect of a low concentration of hydrogen peroxide on metabolism of blood cells]. / Vliianie nizkoi kontsentratsii perekisi vodoroda na metabolizm kletok krovi.

Hydrogen peroxide is known to posses a wide range of physiological effects towards functional activity of cells. We have investigated the influence of H2O2 on the activity of glycolys in the native blood cells. Adding of hydrogen peroxide up to final concentration 50 microM led to decrease of activity some glycolytic enzymes. H2O2 inhibited consumption of glucose by blood cells. Despite the fact that H2O2 is well known as prooxidant, we observed decrease of the level of thiobarbituric acid reactive species in the blood cells after their incubation in the presence of hydrogen peroxide for 2 hours. Based on these data we supposed that effects of hydrogene peroxide occur via signal transduction pathways.

[Arsenite-induced lipid peroxidation in Saccharomyces cerevisiae]. / Arsenit kak induktor processov perekisnogo okisleniia lipidov v kletkakh drozhzhei Saccharomyces cerevisiae.

The ability of sodium arsenite at concentrations of 10(-2), 10(-4), and 10(-6) M to induce lipid peroxidation in Saccharomyces cerevisiae cells was studied. Arsenite at the concentrations 10(-2) and 10(-4) M enhanced lipid peroxidation and inhibited the growth of yeast cells. Enhanced lipid peroxidation likely induced oxidative damage to various cellular structures, which led to suppression of the metabolic activity of cells. Arsenite at the concentration 10(-6) M did not activate lipid peroxidation in cells. All of the tested arsenite concentrations inhibited the activity of alpha-ketoglutarate dehydrogenase and pyruvate dehydrogenase in cells. The inference is made that the toxicity of arsenite may be related to its stimulating effect on intracellular lipid peroxidation.