EXTRACTABLE LIPIDS OF PSEUDOMONAS AERUGINOSA

1. 1. The composition, distribution and turnover of the extractable lipids of Pseudomonas aeruginosa 8602 have been studied. 90% of these extractable lipids were phospholipids, phosphatidyl ethanolamine being the major component under all conditions of growth. There were smaller amounts of bis-phosphatidyl glycerol and phosphatidyl glycerol and a fourth unidentified phospholipid. The phospholipids contained myristic acid, A-hexadecanoic acid, N-octadecanoic acid, hexadec-9-enoic acid and octadec-11-enoic acids as well as the C17 cyclopropane acid, methenyl-hexadecanoic acid, and the C19 cyclopropane acid, methenyloctadecanoic acid. No differences were detected between the extractable lipids of various cell fractions. 2. 2. The major changes in phospholipid and fatty acid composition throughout the growth cycle and under various growth conditions were in the proportion of cyclopropane acids present. These acids increased during the stationary phase and when the cells were grown under conditions of O2 limitation and decreased in limiting Mg2+. 3. 3. Cyclopropane acid synthesis was measured by the incorporation of [Me-14C] methionine during the stationary phase. It occurred faster in phosphatidyl glycerol than in phosphatidyl ethanolamine. Bis-phosphatidyl glycerol apparently was not a substrate. The amount of octadecenoic acid converted into C19 cyclopropane acid was higher in the 1 than in the 2 position of the phospholipids. © 1969.