Peculiarities of the structure of the Pseudomonas fluorescens IMV 247 (biovar II) lipopolysaccharide

The results of the study of the Pseudomonas fluorescens IMV 247 (biovar II) lipopolysaccharide (LPS) isolated from the dry bacterial mass by Westphal' s method and purified by repeated ultracentrifugation are presented. The ma cromolecular organization of the LPS is characterized by the presence of S and R forms of LPS molecules in a 1 : 1 ratio. The structural components of the LPS molecule-lipid A, the core oligosaccharide, and the O-specific pol ysaccharide-were isolated and characterized. 3-Hydroxydecanoic, 2-hydroxydo decanoic, 3-hydroxydodecanoic, and dodecanoic acids proved to be the main l ipid A fatty acids. Glucosamine, phosphoethanolamine, and phosphorus were i dentified as the components of the lipid A hydrophilic portion. Glucose, ga lactose, arabinose, rhamnose, glucosamine, galactosamine alanine, phosphoet hanolamine ne, phosphorus, and 2-keto-3-deoxyoctulonate (KDO) were revealed in the heterogeneous fraction of the core oligosaccharide. The O-specific polysaccharide chain was composed of repeating tetrasaccharide units consis ting of L-rhamnose (L-Rha), 3,6-dideoxy-3-[(S)-3-hydroxybutyramido]-D-gluco se (D-Qui3NHb), 2-acetamido-2,4,6-trideoxy-4[(S)-3-hydroxybutyramido]-D-glu cose (D-QuiNAc4NHb), and 2-acetamido-2-deoxy-D-galacturonic acid (D-GalNAcA ) residues. A peculiarity of the O-specific polysaccharide was that it rele ased, upon partial acid hydrolysis, the nonreducing disaccharide GalNAcA -- > QuiNAc4NHb with a 3-hydroxybutyryl group glycosylated intramolecularly wi th a QuiN4N residue. Double immunodiffusion in agar and lipopolysaccharide precipitation reactions revealed no serological interrelationship between t he strain studied and the P. fluorescens strains studied earlier.