Brovarskaya O. Lipopolysaccharides and extracellular glycopolymers of Ralstonia solanacearum: composion, structure and biological activity.

The dissertation is devoted to investigations of Ralstonia solanacearum lipopolyssaccharides (LPS). LPS have been isolated from 7 strains of R. solanacearum ICMP 750, 6524, 7859, 8115, 7864, 8169, 6189. Their chemical idenfication showed that LPS tested contain all components which are characteristic for this type of polymers. The structures of O-specific polysaccharides (O-PS) of R. solanacearum 6524 and 7859 have been established. They characterized by linear tetrasaccharide units, including three residues of -L-rhamnose and one residue of N-acetylglucosamine. The LPS tested were toxic and pyrogenic. Modifications of LPS lead to the loss of their endotoxic activity, in particular toxicity and pyrogenicity. It was settled, that dephosphorylation and deacylation don't influence the LPS serological activity while succinylation leads to its loss. The comparative studies of phytotoxic activity of R. solanacearum culture liquids (without cells) on germination and growth of seeds showed that R. solanacearum strains 6524 and 6189 displayed the highest activity. Extracellular glycopolymers contained both proteins and carbohydrates. It was shown that charged glycopolymers exerted phytotoxic activity.