[Biological activity of native and modified lipopolysaccharides of Pragia fontium].

Modified lipopolysaccharides (LPS) of Pragia fontium were obtained with germanium complexes (IV) of 2-aminobenzoylhydrazon of salicylic aldehyde (2-NH2-H2Bs), 2-hydroxybenzoylhydrazon salicylic aldehyde (2-OH-H2Bs) and nicotinoylhydrazon of salicylic aldehyde (H2Ns). The modification of LPS was confirmed by IR spectroscopy. Comparative investigations of pyrogenic activity of native and modified LPS showed, that only P. fontium 20125 LPS, modified by germanium complexes with 2-hydroxybenzoylhydrazon of salicylic aldehyde (2-OH-H2Bs) has lost the pyrogenic activity. In the homological reactions of double immunodiffusion in agar it was shown that all modified LPS unlike the native ones lose completely antigenic activity.

[Adhesive properties of Pragia fontium lipopolysaccharides].

Effect of lipopolysaccharides (LPS) and their structure components (lipid A, oligosaccharide core, and O-specific polysaccharides) from 8 strains of P. fontium on the adhesion process have been investigated for the first time. It was demonstrated, that LPS and their structural components may compete with E. coli adhesins and phytohemagglutinin under binding with receptors on the surface of the rabbit erythrocytes. An analysis of different structural components influence indicated, that in comparison with O-specific polysaccharides and core oligosaccharide lipids A of all investigated strains of P. fontium displayed the highest inhibitory action on the adhesion process. It was shown that there existed certain dependence between LPS composition and their effects on the adhesion process. LPS, obtained from P. fontium strains grown at different temperatures (36, 25, 4 degrees C) and characterized by various quantitative and qualitative monosaccharide and fatty acid composition, demonstrated different adhesion properties.

[Chemical characteristic of structure components of Pragia fontium lipopolysaccharides].

Structure components (lipid A. oligosaccharide core, and O-specific polysaccharide) of the lipopolysaccharide from 8 strains of Pragia fontium were obtained as a result of mild acidic hydrolysis. The macromolecular organization of lipopolysaccharides of studied strains was heterogeneous and presented both by S-forms, and R- or SR-forms. It was established that as to fatty acid composition lipids A of tested strains were represented by one chemotype with predominant 3-hydroxytetradecanoic fatty acid. An analysis ofmonosaccharide composition of core oligosaccharides has detected 5 chemotypes, and glucose, galactose, rhamnose, ribose, arabinose, xylose and mannose were identified in them. It was shown that O-specific polysaccharides consisted of glucose, galactose, rhamnose, and mannose that demonstrated their belonging to 4 chemotypes.

[Chemical characteristic and serological activity of Pragia fontium lipopolysaccharides].

Lipopolisaccharides (LPS) of 8 strains of Pragia fontium--representatives of a new genus of Enterobacteriaceae family, was isolated for the first time. It was demonstrated, that lipopolysaccharides yields were 10-20% of dry cells weight. Investigations of monosaccharide composition have determined the presence of glucose, galactose, rhamnose and mannose in lipopolysaccharides, that permitted to establish 4 chemotypes ofpolysaccharide part of LPS. Serological investigations showed immunochemical heterogeneity of Pfontium: 8 investigated strains were divided by the O-antigenicity into 7 serogroups.