Chemical composition of Desulfovibrio desulfuricans lipid A

Abstract

Lipopolysaccharides also called endotoxins are an integral component of the outer membrane of Gram-negative bacteria. When released from the bacterial surface, they interact with a host immune system, triggering excessive inflammatory response. Lipid A is the biologically most active part of endotoxin, and its activity is modulated by the quantity, quality and arrangement of its fatty acids. Desulfovibrio desulfuricans is sulfate-reducing, Gram-negative bacterium that is supposed to be opportunistic pathogens of humans and animals. In the present study, chemical composition of lipid A from various strains of D. desulfuricans was analyzed by gas chromatography/mass spectrometry. It was found that the fatty acid component of the lipid A contains dodecanoic, tetradecanoic, 3-hydroxytetradecanoic and hexadecanoic acids, and its carbohydrate core is composed of glucosamine. The analysis of 3-acyloxyacyl residue of the lipid A revealed the presence of amide-bound 3-(dodecanoyloxy)tetradecanoic and 3-(hexadecanoyloxy)tetradecanoic acids and ester-bound 3-(tetradecanoyloxy)tetradecanoic acid. It was concluded that both fatty acid and 3-acyloxyacyl residue profiles of the lipid A from the studied bacteria were similar to those of E. coli and S.enterica.