Phospholipids of marine proteobacteria of the genus Pseudoalteromonas

The study of the phospholipid composition of 14 type strains of marine prot eobacteria of the genus Pseudoalteromonas showed that phospholipids are the main polar lipid constituents of membranes in these proteobacteria. The ph ospholipid patterns of the strains studied were found to be similar and inv olved five phospholipids typical of gram-negative bacteria, namely, phospha tidylethanolamine, phosphatidylglycerol, bisphosphatidic acid, lysophosphat idylethanolamine, and phosphatidic acid. The major phospholipids were phosp hatidylethanolamine and phosphatidylglycerol, which add up to 89-97% of the total phospholipids; bisphosphatidic acid was dominant among minor phospho lipids. The prevalence of phosphatidylethanolamine (62-77% of the total pho spholipids) and the absence of diphosphatidylglycerol are the characteristi c features of most bacteria of this genus. As in Escherichia coil, the phos pholipid composition of the marine proteobacteria depended on the presence of magnesium in the medium.