RESUMO
The effect of zinc ions on the physiological state of Candida utilis VKM Y-1668 was studied during its chemostat cultivation. The concentration of zinc ions was maintained at a constant level. Zinc was found to inhibit the growth at a concentration of 300 mg/l. The cells were rapidly washed from the fermenter when zinc concentration was increased to 500 mg/l. Zinc uptake by the culture became greater when zinc concentration in the medium was gradually increased. If the yeast was cultivated in the presence of the inhibitor, the content of protein, RNA, DNA and polysaccharides fell while lipid content increased. Growth inhibition by zinc ions interfered with cell division; the cells could not separate from one another and formed catenae and conglomerates.
Assuntos
Candida/efeitos dos fármacos , Zinco/farmacologia , Candida/análise , Candida/citologia , Fenômenos Químicos , Química , Meios de Cultura/metabolismo , Depressão Química , Relação Dose-Resposta a DrogaRESUMO
The purpose of this work was to study the effect of zinc ions on the growth and physiological properties of the chemostat culture of Candida utilis BKM Y-1668. Zinc at a concentration of 250-300 mg/l was found to inhibit the growth of the culture. The resistance of the culture to zinc ions can be increased within 40 generations if the yeast is grown in the regime of chemostat and the concentration of zinc ions is gradually increased. The growth of the resistant culture by zinc ions was inhibited at a concentration of 500 mg/l. If the yeast was cultivated with an addition of the inhibitor, the economic coefficient decreased, while the utilization of glycerol, nitrogen and phosphorus per 1 g of the biomass increased twofold and more; the rate of oxygen uptake by the cells and the rate of carbon dioxide evolution decreased, whereas the concentration of keto and amino acids in the medium increased.
