Cytotoxic effects of menadione on normal and cytochrome c-deficient yeast cells cultivated aerobically or anaerobically

Abstract

Cytotoxic effects of menadione on normal and cytochrome c-deficient yeast cells were examined on the basis of the cell growth rate, NAD(P)H concentration, reactive oxygen production, plasma membrane H+-ATPase activity, and ethanol production. In aerobically or anaerobically cultured yeast cells, NAD(P)H concentration decreased with increasing concentration of menadione, and the recovery of NAD(P)H concentration was proportional to the cell growth rate. However, there was no relationship among the inhibition of the cell growth and reactive oxygen production, plasma membrane H+-ATPase activity, and ethanol production. Among them, ethanol production showed resistance to the cytotoxicity of menadione, suggesting the resistance of glycolysis to menadione. The growth inhibitory effect of menadione depended on the rapid decrease and the recovery of NAD(P)H rather than production of reactive oxygen species regardless of aerobic culture or anaerobic culture and presence or absence of mitochondrial function. The recovery of NAD(P)H concentration after the addition of menadione might depend on menadione-resistant glycolytic enzymes.

Keywords

• Yeast
• Menadione: NAD(P)H
• Growth rate
• Reactive oxygen species
• Proton release