A transient and rapid activation of plasma-membrane ATPase during the initial stages of osmoregulation in the salt-tolerant yeastZygosaccharomyces rouxii

Abstract

Effects of various inhibitors on the intracellular accumulation of glycerol and inorganic ions in a salt-tolerant yeast, Zygosaccharomyces rouxii, were examined for several hours during NaCl-induced salt stress. Cycloheximide strongly inhibited the intracellular accumulation of glycerol during salt stress but chloramphenicol did not. Rapid activation of plasma-membrane ATPase was apparent within 5 min after the start of salt stress and after 1 h a second, slower activation occurred. ATP was maintained at a higher level during salt stress than that in its absence. Experiments with various other inhibitors demonstrated a close relationship between synthesis of glycerol, activation of plasma membrane ATPase and increases in levels of ATP. These results suggest that activation by salt stress of plasma-membrane ATPase may trigger the synthesis of glycerol for osmoregulation.