Studies Regarding Cytotoxicity of Copper, Lead and Zinc Ions Solutions on Living Saccharomices Cerevisae Cells

Andreea Stănilă, Tania Mihăiescu, Antonia Odagiu

Abstract


Brewer’s yeast is a type of fungus formally known as Saccharomyces cerevisae. Along with other Saccharomyces species, brewer’s yeast is used to brew beer and can be also used as a nutritional supplement in active form. To evaluate the cytotoxicity of some heavy metal ions on living Saccharomyces cerevisae cells it were used copper, lead and zinc solutions at different concentrations ranged between 10-3M to 10-5M. The end points for cytotoxicity evaluation are: proliferation rate, lactate dehydrogenase quantification and lipid peroxidation.       Regarding the proliferation rate all the metal ions inhibit the growth of the cells, especially copper ions and the optimal pH was established to be 5.5. Concentrations of 10-3M of Cu2+, Pb2+ and Zn2+ inhibit the proliferation rate about 18% for lead, 24.5% for zinc and 27% for copper after 24h at pH=5.5 and 31.8%, 35% and 43.5% at pH=8. Concerning the cytotoxicity test, if the level of lactate dehydrogenase released is under 0.15 nmoli NADH/min/10.000 cells it is considered that there is no cytotoxic activity in the cell. The results obtained demonstrated that only lead and zinc ions at the concentration of 10-5M could be considered non-cytotoxic on Saccharomyces cerevisae cells. The peroxidation level measured by MDA-TBA complex formed was higher for Cu2+ ions at all concentrations; for Pb2+ and Zn2+ the higher prooxidant activity was determined for the concentration of 10-3M and 10-4M, so the maximum level admitted for this study is 10-5M.


Keywords


grape; brewer’s yeast, heavy metals, cells proliferation

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