DIVERSITY OF THE POLAR LIPIDS OF THE FOOD-BORNE PATHOGEN LISTERIA-MONOCYTOGENES

Listeria monocytogenes is a Gram-positive bacterium that can adapt to high salinity and cold. Because the membrane lipids may play a role in its survival and adaptation, we have examined the polar lipids of L. monocytogenes. Extraction of total lipids from L. monocytogenes yielde d 7 +/- 1 mg/mL wet cells. Polar lipids represented 64% of total lipid s and contained 9% lipid-phosphorus. Polar lipids were separated into 14 components by two-dimensional thin-layer chromatography. Eight comp onents (88% of polar lipids) contained lipid-phosphorus; among these w as one major component (34% of polar lipids). Two other phospholipids were ninhydrin-positive components and accounted for 15% of the polar lipids. Orcinol staining revealed two glyco- or sulfo-lipids accountin g for 9% of polar lipids. Five components (4% of polar lipids) were am ino components free of phosphorus. The major component contained 46% o f its fatty acids as 15:0 anteiso, 24% as 17:0 anteiso, and 11% as 15: 0 iso. The fatty acid profile of the remaining polar lipids was variab le, consisting primarily of 16:0, 18:0, 15:0 anteiso, and 17:0 anteiso . Their unsaturation level was less than or equal to 20%; however, the major phosphoaminolipid component was 46% unsaturated. The ratios of 15:0 anteiso/17:0 anteiso and 15:0 anteiso/15:0 iso were similar in al l classes, averaging 1.5 and 4.5, respectively. Since the adaptation p rocess to stressful environments involves activation of a membrane tra nsport system for the protectant glycine betaine, the membrane lipids may play a role in enabling transport.