Lipids of Pseudomonas

Abstract

Lipids are generally defined as fatty acids, alcohols, hydrocarbons, and compounds containing these substances which are soluble in organic solvents. The lipids most commonly found in bacteria are phospholipids, glycolipids, ornithine amide lipids, fatty acids, and lipopolysaccharides. Phospholipids generally constitute ~40% of the cytoplasmic membrane of bacteria and up to 25% of the outer membrane (mainly localized in the inner leaflet). A generalized structure for a Pseudomonas membrane is shown in Figure 1. It has been found that the predominant phospholipid in both the inner and outer membranes in most Pseudomonas species is phosphatidylethanolamine (Wilkinson, 1988). Ornithine amide lipids are localized in the outer membrane. Lipopolysaccharides are located in the outer leaflet of the outer membrane of gram-negative bacteria. Glycolipids are generally found as storage lipids located in intracellular inclusions but can also be found in the membranes of P. diminuta and P. vesicularis and gram-positive bacteria (Wilkinson, 1988). Carotenoids and hydrocarbons may be found in the cytoplasmic membrane.