Phospholipid Biosynthesis in the Moderately Halophilic Bacterium Vibvio costicola During Adaptation to Changing Salt Concentrations

Abstract

The metabolism of phospholipids in Vibrio costicola, a moderately halophilic bacterium, has been investigated in relation to sudden changes in salinity. Both the absolute and relative rates of biosynthesis of phosphatidylglycerol and phosphatidylethanolamine depend on the salt concentration of the medium; a sudden rise in salt concentration has an instantaneous inhibitory effect on phospholipid biosynthesis, but this inhibition lessens as. the bacteria adapt to the higher salinity. There is no turnover of phospholipids during isotonic growth, nor when the salt concentration is suddenly altered. The alterations in biosynthetic rates of phosphatidylglycerol and phosphatidylethanolamine that occur after sudden changes in salt concentration are consistent with the known compositional changes. We conclude that the mechanisms of changes in phospholipid composition during adaptation to raised or lowered salt concentrations are not necessarily the same.