Abstract
ZnO nanoparticles (NPs) are widely used but exposure to them can cause the generation of reactive species and perturb the redox status of organisms. In this study, we synthesized ZnO NPs using a biosynthesis route and investigated their effects on oxidative stress parameters in Saccharomyces cerevisiae. Floral extracts from Tagetes erecta L. were reacted with 125 mM zinc acetate at a ratio of 1:50, 85°C, and pH 12, for 1 h to prepare the ZnO NPs. The NPs had a uniform hexagonal wurtzite structure, with a size of ∼18 nm and high stability. The ZnO NPs showed a concentration-dependent perturbation effects on cell growth and oxidative stress parameters in S. cerevisiae, and accelerated aging markers. Exposing stationary phase S. cerevisiae 699 and SP4 cells to different NP concentrations resulted in high levels of thiobarbituric acid reactive substances. Treatment of aged SP4 cells with NPs led to a decrease in the catalase activity and an increase in the CuZn superoxide dismutase (SOD) activity. In the 699 strain, the catalase and CuZnSOD activities decreased, while the MnSOD activity increased, thereby indicating the possible accumulation of hydrogen peroxide and superoxide anions within the cytosolcausing lipid peroxidation. Thus, the findings obtained in the present study suggest that stable biogenic ZnO NPs may induce oxidative stress conditions in living systems, especially at high concentrations, and caution is advised against their extensive use.
Published Version
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