SUMMARY: The lipopolysaccharides (LPSs) from four isolates of were examined. One isolate was virulent and capsulate, and it produced extracellular polysaccharide (EPS). Three were avirulent, of which one was capsulate and produced EPS; the remainder were non-capsulate and did not produce EPS. LPS was recovered from the cells and from the culture medium. Material extracted from the cells using phenol-water was indistinguishable from LPS extracted with phenol-chloroform-light petroleum. Acid hydrolysis released lipid A which contained in all cases glucosamine, phosphate and the fatty acids 12:0, 14:0 and 3-OH 14:0. The carbohydrate released by mild acid hydrolysis was resolved by gel permeation chromatography into three components: I, a partially included species identified as core substituted with a short sidechain of fucose, galactose and glucose; II, an unsubstituted core oligosaccharide containing heptose, glucose, uronic acid, amino compounds and 3-deoxy-2-octulosonic acid (KDO); III; a totally-included low fraction containing KDO, phosphate and amino compounds. The sidechain component was missing from LPS of one of the non-capsulate strains that did not produce EPS. This strain is believed to lack UDP-glucose-4-epimerase, a key enzyme in the biosynthesis of galactose. Galactose (with glucose and uronic acid) is known also to be a component of EPS. Defects in galactose synthesis may therefore affect the assembly of LPS as well as EPS.


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