Structure of the Core Oligosaccharide from the Lipopolysaccharide of Pseudomonas aeruginosa PAC1R and Its Defective Mutants

Abstract

Lipopolysaccharides were isolated from Pseudomonas aeruginosa PAC 1 R and its lipopolysaccharide-defective mutants. Core fractions were obtained from them following mild acid hydrolysis, by gel chromatography using Bio-Gel P6. The core fraction from the parent strain contained glucose, rhamnose, galactosamine, heptose and alanine in the approximate molar ratios 3 : 1 : 1 : 1 : 1 while core fractions from the defective mutants lacked rhamnose and/or one, two, or three glucose units. Methylation analysis of the core fractions including identification of the partially methylated alditol acetates by combined gas-liquid chromatography and mass spectroscopy allowed the formulation of possible structures. These were confirmed by 3C nuclear magnetic resonance spectroscopy. Fractions consisting of core to which was attached unpolymerised 0-antigen were isolated from the parent strain and one of the mutants and analysed in the same way to identify the attachment point of the 0-antigen.The combined data leads to the formulation of the core oligosaccharide of PAClR and its mutants as follows:

Cytokeratins mediate epithelial innate defense through their antimicrobial properties

“…(G) Bactericidal activity of 19-mer (200 μg/ml) was only slightly affected by mutations in LPS for P. aeruginosa (strain PAC1R, serotype 03). PAC1RalgC-and PAC605 have incomplete LPS core oligosaccharide and are O antigen deficient (27), and PAC557 has a complete core but is O antigen deficient, while PAC611 has mutations only in the core (64).…”

Variable cross-reactivity of Pseudomonas aeruginosa lipopolysaccharide-core-specific monoclonal antibodies and its possible relationship with serotype

“…In contrast, MH-4H7 did not react at all to these deep rough strains PAC556 and PAC611, as previously reported (Yokota et al, 1989). PAC556 is reported to lack only the L-rhamnose residue of the LPS outer core region compared with PAC557 (Rowe & Meadow, 1983). The other anti-core mAbs, OM-1D6 and NM-3G8, were not observed to bind to a series of strains, including a parental strain of serotype A, at all.…”

“…P . aeruginosa PAC1, PAClR (Habs serotype 3) and their LPSdefective mutant strains (Rowe & Meadow, 1983) were a kind gift from P. M. Meadow, University College of London, London, UK. Clinical isolates of P .…”

“…aeruginosa PAC1 and PAClR (Rowe & Meadow, 1983), of which LPS core structures had been well defined, was determined by ELISA using whole cells as a solid antigen (Table 2). First, we determined the serotype of these strains according to Homma's classification by agglutination testing using mAbs (Mei-assay).…”

“…aeruginosa, the outer core region commonly contains L-rhamnose, Dglucose, D-galactosamine and L-alanine, but the molar ratio of these constituents seems to be heterogeneous between strains (Wilkinson, 1983). However, the detailed chemical structure of this region has been reported only for strain NCTC1999 (Drewry et al, 1975), and PAClR and its defective mutants (Rowe & Meadow, 1983), and their proposed partial structures were different from each other. Thus, the extent of the heterogeneity of the LPS core region is still obscure.…”