CHARACTERIZATION OF O-ANTIGENS FROM DIFFERENT STRAINS OF PSEUDOMONAS-SYRINGAE PV TABACI

O-Antigens (lipopolysaccharides, LPS) were isolated by NaCl extraction from microbial biomass of Pseudomonas syringae pv. tabaci and purifie d by ultracentrifugation. Individual structural components of the LPS macromolecule (O-specific polysaccharide (O-PS), core oligosaccharide, and lipid A) were obtained and characterized. Fatty acids 3-OH-C-10:0 , C-12:0, 2-OH-C-12:0, 3-OH-C-12:0, C-16:1, C-16:0, C-18:0, and C18:0 were identified in the lipid A composition. Glucosamine, ethanolamine, and phosphoethanolamine were found in the hydrophilic part of the lip id A macromolecule in all strains tested. Lipid A preparations contain ed phosphorus and amino acids. Rhamnose, glucose, glucosamine, 2-keto- 3-deoxyoctulosonic acid, heptose, alanine, and phosphorus were identif ied as the main core components. The strains differed in O-PS structur e. We describe the O-chain of LPS in strain P-28. It contains repeatin g units of the following structure: [GRAPHICS] The O-PS structures of LPS from strains P-28 and 225 are identical, however, they differ subs tantially from that of strain 223. Both structures from strains 223 an d 225 were reported previously. Antibodies to antigenic epitopes of O- PS, core, and lipid A were revealed in O-serum against the whole bacte rial cells. Correlation of O-PS structure with the serological groupin g of strains was observed.