Studies of Lipopolysaccharides from Pseudomonas aeruginosa

Abstract

Lipopolysaccharides from 13 strains of Pseudomonas aeruginosa representing seven serotypes of the Habs scheme have been analysed. The lipid A fractions, obtained by mild acid hydrolysis of the lipopolysaccharides, contained phosphorylated glucosamine residues substituted with dodecanoic, hexadecanoic, 2-hydroxydodecanoic, 3-hydroxydecanoic, and 3-hydroxydodecanoic acids (hexadecanoic acid and 2-hydroxydodecanoic acid were absent from one lipid A). Low-molecular-weight solutes released during the mild hydrolyses included 2-keto-3-deoxyoctonic acid, inorganic orthophosphates and pyrophosphates, ethanolamine mono, pyro and triphosphates. For most strains two polysaccharide fractions, one of which appeared to be the common core polysaccharide, were obtained. The major identifiable components and their approximate proportions in the core polysaccharides were glucose (3 -4), rhamnose (l), galactosamine (l), alanine (1 -1.5), phosphorus (4-6) and heptose (1 -2). Rhamnose was absent from one polysaccharide; another lacked both rhamnose and alanine but contained glucosamine. Small amounts of various amino sugars found in other core polysaccharides could be associated with the presence of higher-molecular-weight material. Such material was isolated from strain NCIB 8626.The high-molecular-weight polysaccharides obtained from ten strains were probably heterogeneous and consisted mainly of amino compounds, though rhamnose was a major component of four polysaccharides and arabinose was present in another. Fucosamine was the most common amino sugar, but quinovosamine, glucosamine, galactosamine, a possible aminohexuronic acid and unidentified amino compounds were also detected.The results of the survey are discussed in terms of the serological classification of the bacteria and of their sensitivity to EDTA.Although studies of bacterial lipopolysaccharides have broadened considerably in recent years, compositional and structural data remain rather fragmentary and superficial for most organisms outside the family Enterobacteriaceae. For various reasons, efforts to rectify this situation for pseudomonads are being made in several laboratories, with the focus of interest being Pseudomonas aeruginosa. Despite the existence for P. aeruginosa of several serological typing schemes based on thermostable antigens (presumptively lipopolysaccharides), the chemical foundations for these schemes are not known. Thus, the elaboration and elucidation of the chemistry of 0-antigens from P. aeruginosa are important objec-

Heterogeneity of lipopolysaccharides from Pseudomonas aeruginosa: analysis of lipopolysaccharide chain length

“…It has been shown that S. paratyphi B and S. typhimurium can synthesize a Ti polysaccharide and an 0 polysaccharide attached to the same core (37,41) and that the synthesis of the two molecules is independent (37). Other P. aeruginosa strains may also be able to synthesize more than one type of LPS with different 0-antigenic side chains (8,30,57,58). The highmolecular-weight polysaccharide released from LPS of these strains has been resolved into amino sugar-rich and neutral sugar-rich fractions when separated by gel permeation chromatography (30, 57, 58).…”

“…charides has been complicated in some cases by chemical heterogeneity of the polysaccharide chains (8,9,30,58). In some instances, the polymeric material has been resolved into amino sugar-rich and neutral sugar-rich fractions (30,58). The biological significance of such fractions is unclear, but a possible explanation is that P. aeruginosa strains produce multiple types of molecules with chemically distinct polysaccharide chains.…”

“…The characterization of P. aeruginosa 0-specific polysac-* Corresponding author. charides has been complicated in some cases by chemical heterogeneity of the polysaccharide chains (8,9,30,58). In some instances, the polymeric material has been resolved into amino sugar-rich and neutral sugar-rich fractions (30,58).…”

“…The most outstanding differences include the unusually high phosphate content (33,58), the presence of L-alanine in the core (33,57), and the high levels of amino sugars and uronic acids in the 0 side chain (8,33). The characterization of P. aeruginosa 0-specific polysac-* Corresponding author.…”

Studies on the Chemical Composition of Lipopolysaccharide from Neisseria meningitidis Group B

“…Acid-hydrolysed samples of the cleaved polysaccharide (1 M-HCl at 100 "C for 30 min) were chromatographed on plates of silica gel GF (Analtech) in methanol/pyridine/lO M-HCI/ water (32:4: 1 :7, by vol.) (Wilkinson & Galbraith, 1975). Standards of 2,6-diaminopimelic acid and ethanolamine were run with the samples.…”