The dissertation is devoted to the study of the peculiarities of the chemical composition, functional and biological activity of lipopolysaccharides (LPS) and their structural components of the representatives of Pantoea agglomerans species. LPSs were isolated from 14 strains of P. agglomerans by a water-phenol method and chemically characterized. The yield of LPS was from 3,4 to 14,0 % (depending on the strain). Relatively high content of carbohydrates (29,0-51,0 %), trace amounts of protein (up to 0,8 %), and the high content of nucleic acids (7,7-13,5 %) have been determined in the studied LPS. LPSs of tested P. agglomerans strains were heterogeneous on the monosaccharide and fatty acid composition and on the basis of which the strains can be divited into eight and seven groups, respectively.
It was established that the structures of P. agglomerans 8674т, 7604 and 7969 lipids A are heterogeneous and characterized by different degrees of acylation and are represented by hexa-, penta- and tetracylated types. It was established that the O-specific polysaccharide (OPS) structure of type P. agglomerans strain is represented by branched pentasaccharide, which includes three residues of rhamnose and two glucose residues, one of which is in the lateral position and has a β-configuration. The same structure was characteristic also for P. agglomerans 7604 OPS, but only difference was that the glucose residue in the lateral position has the α-configuration. Structures of P. agglomerans 7969 OPS essentially differs from the previous two structures. It was represented by a linear heteropolymer consisting of rhamnose, fucose, mannose and 2-acetamido-2-deoxyglucose residues. This structure is heterogeneous due to non-stoichiometric replacement of the glucosamine residue in position 6 with glycero-1-phosphate. Based on the results of cross-reactive serological reactions, strains of P. agglomerans were divided into ten serogroups.
Investigated LPS are characterized by varying degrees of toxicity and pyrogenicity. According to the pyrogenic activity investigated LPS can be divided into 3 groups: non pyrogenic (P. agglomerans 7960a, 8488, P1a and 9668), weakly pyrogenic (P. agglomerans 8674т, 8456, 7969, 7460 and 9637) and pyrogenic (P. agglomerans 8490, 8606, P324, 7604 and 9649). The highest toxic effect was shown for LPS of P. agglomerans 9637, 9649 and P324. The lowest toxic activity was character for LPS of the P. agglomerans 8674т strain. P. agglomerans LPS, modified with complex compounds of germanium and stanum, completely loss the ability to exhibit toxic activity in LD50 parameters.
It was shown that P. agglomerans LPSs participate in adhesive processes: the higher LPS concentration in the reaction mixture, the lesser interaction occurred between Escherichia coli cells and the surface structures of erythrocytes. A comparative study of complex indicators of peripheral blood cells of a healthy donor before and after treatment with LPS solutions, show that almost all indicators do not exceed the normal values. LPS of two P. agglomerans 8674т and P324 strains showed an essential influence on peptidase activity of bacillus.
