Investigation of Dependency of Boric Acid and Lithium Metaborate Induced Yeast Toxicity on the Expressions of Antioxidative and Apoptotic Genes

Abstract

Boric acid and its less-known derivative lithium metaborate are inorganic acids used in a wide and diverse array of industrial and clinical applications. In particular, boric acid is accepted as a natural antimicrobial agent due to its activity on many different microbial species. We have examined the possible dependency of boric acid and lithium metaborate-induced yeast toxicity on the deletion of antioxidative CTT1, TRR2 and GSH2 genes and the expressions of certain important pro- and anti-apoptotic genes. While the investigated antioxidative genes have no function in the protection against boric acid mediated toxicity, the cell proliferation percentages of △GSH2 and △TRR2 mutants significantly decreased to approximately 57% and 75%, respectively, after 0.25% LMB treatment for 12 h compared to the wild yeast strain. The relative expressions of the AIF and NDI genes were generally induced for the highest concentrations of the drugs compared to the control. Similarly, anti-apoptotic BIR1 was also generally induced compared to the control, which indicates the importance of this gene in the resistance of yeast cells against BA and its derivatives mediated toxicity. These new findings are significant in terms of adding new data to the literature on understanding the toxic effect mechanisms of boron compounds.