Lipids of Salmonella typhimurium and Escherichia coli: Structure and Metabolism

Abstract

The nature and quantity of the phospholipids of S. typhimurium and E. coli K-12 were examined. The main classes of phospholipids, phosphatidylethanolamine, phosphatidylglycerol and cardiolipin were completely characterized. Four minor compounds were detected: phosphatidylserine, phosphatidic acid and 2 partially characterized lipids. The phospholipid composition of the 2 organisms is quite similar, the only difference is the absence of one of the minor components and a decreased level of all components in E. coii. A study of the turnover of the phosphate in the phospholipids demonstrated no turnover in phosphatidylethanolamine, a slow turnover in phosphatidylglycerol and a slow turnover in cardiolipin with (possibly) a transfer of phosphate from phosphatidylglycerol to cardiolipin. The amino acid phenylalanine is shown to become incorporated intact into lipid compounds which were partially characterized. Methods for the isolation and separation of lipids were examined for their utility with these bacteria.