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S G Wilkinson

Publications and source records attributed to S G Wilkinson.

112 records · Page 7Linked to original sources
PubMedDate not supplied

Structural alterations in the envelope of a gentamicin-resistant rough mutant of Pseudomonas aeruginosa.

Comparative studies of a gentamicin-sensitive strain (P28-0) of Pseudomonas aeruginosa and a gentamicin-resistant mutant (P23-800) have been carried out. No aminoglycoside-modifying enzymes were detected in extracts of the mutant. Electron microscopy of thin sections and the loss of O-antigenicity suggested that resistance of the mutant to gentamicin was related to an alteration in the outer membrane. Analysis of the lipopolysaccharide (LPS) components of the cell walls revealed significant differences. The LPS from strain P28-0 was typical of wild-type P. aeruginosa strains of Habs serotype O6, with quinovosamine and aminogalacturonic acid as O-specific aminocomponents. The LPS from the resistant mutant lacked the O-specific polymer, but had a core oligosaccharide similar to that of the parent strain. Both LPS were rich in phosphorus, part of which was present in triphosphate residues. Although the 31P nuclear magnetic resonance spectra of the LPS differed in some respects, these differences did not seem to correlate with the disparity in sensitivity to gentamicin of the two organisms.

Cell Wall↗
PubMedDate not supplied

Composition and structure of lipopolysaccharides from Pseudomonas aeruginosa.

Lipopolysaccharides from Pseudomonas aeruginosa seem to have the same general architecture as those from enterobacteria. Points of difference include the fatty acid composition and the unusually high degree of phosphorylation (triphosphate residues have been detected). The outer region of the core oligosaccharides is also distinctive; its components are D-glucose, L-rhamnose, D-galactosamine, and possibly L-alanine. Lipopolysaccharide preparations contain a relatively low proportion of complete (S-form) molecules, but in some cases contain a significant proportion of molecules that have a single O-specific repeating unit attached to the core oligosaccharide. The O-specific side chains are typically rich in amino sugars, including novel types. Components identified so far are 2-amino-2-deoxyglucose, 2-amino-2-deoxygalactose, 2-amino-2,6-dideoxyglucose, 2-amino-2,6-dideoxygalactose, 2-amino-2-deoxygalacturonic acid, 2,4-diamino-2,4,6-trideoxyglucose, 2,3-diamino-2,3-dideoxyhexuronic acids (with the D-gluco-, D-manno-, and L-gulo-configurations), and 2,3-(2-methyl-2-imidazolino-5,4)-2,3-dideoxymannuronic acid. In some cases, polymeric material enriched in neutral sugars can be isolated from the O-specific fractions of partly degraded polysaccharides.

Antigens, Bacterial↗