The distinctive features 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 macromolecular 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 polysaccharide--were isolated and characterized. 3-Hydroxydecanoic, 2-hydroxydodecanoic, 3-hydroxydodecanoic, and dodecanoic acids proved to be the main lipid A fatty acids. Glucosamine, phosphoethanolamine, and phosphorus were identified as the components of the lipid A hydrophilic portion. Glucose, galactose, arabinose, rhamnose, glucosamine, alanine, phosphoethanolamine, 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 consisting of L-rhamnose (L-Rha), 3,6-dideoxy-3-(S)-3-hydroxybutyramido]-D-glucose (D-Qui3NHb), 2-acetamido-2,4,6-trideoxy-4(S)-3-hydroxybutyramido-D-glucose (D-QuiNAc4NHb), and 2-acetamido-2-deoxy-D-galacturonic acid (D-GalNAcA) residues. A peculiarity of the O-specific polysaccharide was that it released, upon partial acid hydrolysis, the nonreducing disaccharide GalNAcA-->QuiNAc4NHb with a 3-hydroxybutyryl group glycosylated intramolecularly with a QuiN4N residue. Double immunodiffusion in agar and lipopolysaccharide precipitation reactions revealed no serological interrelationship between the strain studied and the P. fluorescens strains studied earlier.