Metabolism of the Glucosyl Diglycerides and Phosphatidylglucose of Staphylococcus aureus

Abstract

A glucose containing lipid, phosphatidylglucose (probably 3- sn -phosphatidyl-1′-glucose) and a lipid tentatively identified as phosphatidylethanolamine have been characterized in the lipids of Staphylococcus aureus . These lipids together comprise less than 2% of the total phospholipids of exponentially growing S. aureus and accumulate to 14% of the total phospholipid in stationary-phase cells. These lipids lost no ³² P when cells grown with H ₃ ³² PO ₄ were transferred to nonradioactive medium during the exponential growth phase. This was in marked contrast to the other phospholipids which lost ³² P rapidly. The loss of ³² P from phosphatidic acid and cardiolipin in exponentially growing cells was biphasic, suggesting heterogeneity of phospholipid phosphate metabolism. The mono- and diglucosyl diglycerides showed a rapid loss of ¹⁴ C-glucose during growth in nonradioactive medium but no loss of ¹⁴ C from the fatty acids of these lipids. The ¹⁴ C in the glucose and fatty acids of the glucosyl diglycerides was derived from glucose.