Lipid A mutants of Vibrio cholerae: isolation and partial characterization

Vibrio cholerae mutants resistant to common antibiotics and neutral and anionic detergents were isolated. Analysis of isolated outer membranes revealed a significant deficiency in the acylation of lipid A in the resistant strains. The content of amide-linked and ester-bound fatty acids in the lipid A of the mutant strains compared to that of the wild type was about 50-56% and 29-37% respectively. This defect was specific for lipid A as there was no change in the acylation of phospholipids. The reduction in fatty acid content of lipid A was reflected in the altered endotoxic properties in the mutant strains.