The major glycerophospholipids of the predatory and parasitic bacterium Bdellovibrio bacteriovorus HID5

Bdellovibrio are small motile bacteria that attack and parasitize larger Gram-negative bacteria and since they might have practical applications, these organisms are attracting the attention of researchers as indicated by the sequencing of the B. bacteriovorus genome. There is an earlier report showing that B. bacteriovorus scavenges fatty acids from the host cell during its parasitic phase otherwise the biochemical nature of its lipids, particularly its complex lipids, remains unknown. We here report on the phospholipid classes of an axenically cultured host-independent strain (HID5). Phospholipids and fatty acids were identified by a variety of chromatographic procedures and high-resolution mass spectrometric techniques. Phosphatidylethanolamine was the major phospholipid and phosphatidylserine, cardiolipin, phosphatidylglycerol, and N-acylphosphatidylethanolamine were also identified. The major fatty acids were 16:0, 16:1, 18:1, and 9,10-Mt C16:0 (cyC17:0). Unlike another predatory bacterium, Bacteriovorus stolpii strain UKi2, sphingolipids were not detected in B. bacteriovorus by the procedures used in this study. This is consistent with the apparent lack of genes coding for sphingolipid biosynthesis enzymes in the B. bacteriovorus genome database. The results are consistent with the separation of Bdellovibrio and Bacteriovorus into separate genera.