A NOVEL SULFONIC-ACID ANALOG OF CERAMIDE IS THE MAJOR EXTRACTABLE LIPID OF THE GRAM-NEGATIVE MARINE BACTERIUM CYCLOBACTERIUM-MARINUS WH

The extractable lipids of the gram-negative, sea-water bacterium Cyclo bacterium marinus strain WH contain about 94% of polar components whic h consist of two phospholipids, phosphatidylethanolamine (29% of the t otal lipids) and phosphatidylcholine (7%), and two phosphorus-free lip ids. One of the latter has been shown to be a novel sulfonic-acid anal ogue of ceramide, 2-D-(2'-D-hydroxy-13'-methyltetradecanoyl) amino-3-D -hydroxy-15-methylhexadec-4 (E)-en-1-sulfonic acid (48%), and other is a lipodipeptide, 13'-methyltetradecanoyloxy)-15-methylhexadecanoyl] g lycyl-L-serine (11%), which has so far been found only in a Flavobacte rium sp. strain. The dominant fatty acid residues of the phospholipids are iso-15:0, n-16:0, 16:1 and 18:1, the acyl residues linked to the sn-1 carbon of the glycerol moiety being somewhat more saturated as co mpared with those located at the sn-2 position. A new procedure for de termination of the absolute configuration of 2- and 3-hydroxy fatty ac ids is briefly described. (C) 1998 Elsevier Science B.V.