Spontaneous release of lipopolysaccharide by Pseudomonas aeruginosa

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Abstract
P. aeruginosa PAO grown in glucose mineral salts medium released lipopolysaccharide which was chemically and immunologically similar to the cellular lipopolysaccharide; it also possessed identical phage E79-inactivating properties. Through neutralization of phage activity and hemolysis inhibition assays, the organism was found to liberate lipopolysaccharide at a constant rate during log-phase growth equivalent to 1.3-2.2 ng/108 cells over a growth temperature range of 25-42.degree. C. AT 19.degree. C, a lipopolysaccharide was released which was deficient in phage-inactivating activity but retained its immunological properties. Chemical analysis of lipopolysaccharide extracted from cells grown at 19.degree. C showed a deficiency in the O-side-chain component fucosamine. Gel exclusion chromatography of the polysaccharide fraction derived from lipopolysaccharide isolated from cells grown at 19.degree. C exhibited a decreased content of side-chain polysaccharide and a difference in the hexosamine:hexose rati. The results of sodium dodecyl sulfate-polysacrylamide gel electrophoretic analysis confirmed these results and established that an essentially normal distribution of side-chain repeating unit lengths were found in the 19.degree. C preparation. A decrease in the frequency of capping R-form lipopolysaccharide at 19.degree. C is suggested.