Chemical Comparison of the Polysaccharide Portions of 'Shigella' Lipopolysaccharides and Their Relation to Virulence.

摘要

Lipopolysaccharides (LPS) were extracted from virulent and avirulent strains of Shigella flexneri 2a, S. flexneri 1b, S. sonnei, and E. coli-S. flexneri hybrids in an effort to determine if the difference in virulence could be explained by chemical differences in the polysaccharide portion of the lipopolysaccharides. Comparison of the monosaccharide content of LPS from virulent and avirulent strains grown under different conditions showed a decrease in length of the antigenic O side chains for avirulent organisms grown in BHI broth. Thus length of the O-side chain may be involved in virulence. Fatty acid analysis of the lipid A material from virulent and avirulent organisms showed no difference fatty acid content. Studies of LPS from Shigella-Salmonella hybrids indicate that some of these hybrids may produce LPS characteristic of both parents. LPS analysis of components from two strains of Neisseria gonorrhoeae are also presented.