Abstract
Inhibition of the growth of Saccharomyces cerevisiae was evident at concentrations of 0.5 mM Mn2+ or higher, but a tolerance to lower Mn2+ concentrations was observed. The inhibitory effects of 2.0 mM Mn2+ were eliminated by supplementing the medium with excess Mg2+ (10 mM), whereas addition of excess Ca2+ and K+ had negligible effect on Mn2+ toxicity. Growth inhibition by Mn2+, in the absence of a Mg2+ supplement, was attributed to Mn2+ accumulation to toxic intracellular levels. Mn levels in S. cerevisiae grown in Mg2+-supplemented medium were severalfold lower than those of cells growing in unsupplemented medium. Mn2+ toxicity was also influenced by intracellular Mg, as Mn2+ toxicity was found to be more closely correlated with the cellular Mg:Mn ratio than with cellular Mn levels alone. Cells with low intracellular levels of Mg were more susceptible to Mn2+ toxicity than cells with high cellular Mg, even when sequestered Mn2+ levels were similar. A critical Mg:Mn ratio of 2.0 was identified below which Mn2+ toxicity became acute. The results demonstrate the importance of intracellular and extracellular competitive interactions in determining the toxicity of Mn2+.
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Received: 18 June 1997 / Received last revision: 10 January 1998 / Accepted: 24 January 1998
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Blackwell, K., Tobin, J. & Avery, S. Manganese toxicity towards Saccharomyces cerevisiae : Dependence on intracellular and extracellular magnesium concentrations. Appl Microbiol Biotechnol 49, 751–757 (1998). https://doi.org/10.1007/s002530051242
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DOI: https://doi.org/10.1007/s002530051242