Cell membrane phospholipids and their constituent fatty acids in dividing and nondividing cells of Micrococcus lysodeikticus

Abstract

Changes occurring in the cell membrane of nondividing cells of Micrococcus lysodeikticus disIIp+ grown in the presence of the mucopeptide synthesis inhibitor D-cycloserine include (a) an increase in the relative amount of diphosphatidylglycerol with a concomitant decrease in the relative content of phosphatidylglycerol, (b) a small increase in the relative palmitic acid content of phosphatidylinositol, and (c) leakage of membrane components into the growth medium. Growth of the organism in the presence of both D-cycloserine and D-alanine (which prevents the effects of D-cycloserine on cell division and mucopeptide synthesis) prevents the above changes in the cell membrane, demonstrating that secondary damage to the cell membrane can occur as a result of inhibition in mucopeptide synthesis. Growth of the organism in the presence of D-cycloserine and pantoyl lactone prevents the leakage of membrane components and cell division inhibition. Possible relationships of these changes to cell division are discussed.