[The efficacy and outlook for the study of live vaccines for the prevention of melioidosis]. / Effektivnost' i perspektivy issledovaniia zhivykh vaktsin dlia profilaktiki melioidoza.

The effect of immunization with Burkholderia pseudomallei, (Pur- and Ts), heterologous vaccines and the recombinant culture of Francisella tularensis RM2, carrying a plasmid with fragments of B. pseudomallei chromosome, was studied on four species of experimental animals, essentially differing by their sensitivity to melioidosis. B. pseudomallei mutants formed the statistically significant level of protection in subcutaneously challenged animals, moderately sensitive to melioidosis, but were not effective when tested, under the same conditions, in animals, highly sensitive to melioidosis. The effect produced by the experimental vaccines under study in animals of all species, subjected to aerogenic challenge, was leveled. The study showed good prospects for the use of tularemia vaccine with a view to create heterologous immunity to melioidosis and the possibility of its use as the basis of bivalent gene engineering vaccine.

[The outlook for the development of live vaccines for the prevention of melioidosis]. / Perspektivy razrabotki zhivykh vaktsin dlia profilaktiki melioidoza.

The effectiveness of immunization with Burkholderia pseudomallei attenuated strains (Pur and Ts), heterologous vaccines and the recombinant culture of Francisella tularensis RM2 carrying a plasmid with fragments of B. pseudomallei chromosome was studied in four species of experimental animals, essentially differing in their sensitivity to melioidosis. The most immunogenic B. pseudomallei mutants, introduced subcutaneously, created a statistically significant level of protection in animals, moderately sensitive to melioidosis, but proved to be ineffective in highly sensitive animal models when tested under the same conditions. In aerogenic infection the effectiveness of the experimental vaccines under study in all species of the animals was on the same level. The study showed good prospects of using tularemia vaccine for inducing heterologous immunity to melioidosis, as well as the possibility of its use as the basis of a bivalent gene-engineering vaccine.

[Thermostable Pseudomonas pseudomallei hemolysin]. / Termostabil'nyi gemolizin Pseudomonas pseudomallei.

The chemical nature of thermostable P.pseudomallei hemolysin has been determined. This substance is glycolipid, synthesized by bacteria at the stationary phase of growth under the conditions of the prevalence of the source of carbon over the source of nitrogen in the nutrient medium. The hemolytic activity of thermostable hemolysin has a delayed character and is more pronounced in P.pseudomallei R-forms.

[The isolation and characteristics of cloned strains of Pseudomonas pseudomallei phages]. / Poluchenie i kharakteristika klonirovannykh linii fagov Pseudomonas pseudomallei.

On the basis of museum strains of the melioidosis agent Pseudomonas pseudomallei, 14 pure lines of bacteriophages were isolated belonging to morphological groups IV and V according to the classification by A. S. Tikhonenko. These phages show a broad bacteriolytic range as far as museum P. pseudomallei cultures are concerned. It was determined that some phages isolated from the same melioidosis culture and belonging to the same morphological type display different bacteriolytic activity. It is demonstrated that some strains of melioidosis agent are characterized by polylysogeny.

[The effect of the acid exopolysaccharide produced by the causative agent of melioidosis on macrophage function]. / Vliianie kislogo ékzopolisakharida, produtsiruemogo vozbuditelem melioidoza, na funktsional'nuiu aktivnost' makrofagov.

Acid exopolysaccharide of the melioidosis agent, isolated from the slime of alysogenic strain of Pseudomonas pseudomallei SVBDO-141 inhibits the capture of sheep erythrocytes--55Fe by mouse peritoneal macrophages. Administration of the sheep erythrocytes--55Fe, sensibilized by acid exopolysaccharide was proved not to have an antiphagocytic effect. Inhibition of phagocytic macrophagal activity depends on the conditions of isolation of acid exopolysaccharide.

[Stability of bacterial aerosols in static conditions]. / Ustoichivost' bakterial'nykh aérozolei v staticheskikh usloviiakh.

The influence of acid exopolysaccharides of some Pseudomonas species on the viability and fractional disperse composition of Salmonella marcescens-9 aerosol under static conditions has been studied. Acid exopolysaccharides have been shown to form membranes around bacteria. These membranes, due to their adsorptive and water-retaining properties, seemingly enhance the viability of bacteria in aerosol, both in the process of its generation and during its suspension in the air under static conditions with different values of relative humidity.

[The level of spontaneous phage production and sensitivity to melioidosis phages of museum cultures of Pseudomonas pseudomallei]. / Uroven' spontannoi fagoproduktsii i chuvstvitel'nost' k melioidoznym fagam muzeinykh kul'tur Pseudomonas pseudomallei.

The phage-producing activity and sensitivity of museum cultures of a melioidosis agent to melioidosis phages have been studied. Most cultures show spontaneous phage-production, though its level differs in strains. Some of the melioidosis cultures demonstrate lack of phages. The fact that these strains have different sensitivity to chloroform lysate of cultures producing phages indicates their possible lysogenic state. Electron microscopy has shown the presence of at least tow morphological types of phages in P. pseudomallei C-141. These data confirm existence of polysogeny in the melioidosis agent.

[The morphological characteristics of mucoid variants of Pseudomonas pseudomallei]. / Morfologicheskaia kharakteristika slizistykh variantov Pseudomonas pseudomallei.

Two types of mucoid colonies formed by P. pseudomallei cultivated on solid culture media have been studied by the method of electron cytochemistry. The intercellular material of primary mucoid colonies has been found to positively react with ruthenium red, which is indicative of its polysaccharide nature. Slime is the product secreted by P. pseudomallei and participates in the formation of the pseudocapsule and colonies. The intercellular material seems to be a sum of biopolymers based on the products of destroyed bacterial cells.

[The polysaccharide component of Pseudomonas pseudomallei slime]. / Polisakharidnyi komponent slizi Pseudomonas pseudomallei.

The polysaccharide component contained in the slime of the causative agent of melioidosis was obtained. This component was found to be a biopolymer, mainly of the carbohydrate nature, consisting of galactose, glucose, mannose, rhamnose and two unidentified carbohydrates. The slime polysaccharide component contained two thermostable and acid-resistant antigens. The action of alkali led to the loss of one of these antigens. Rabbit antisera to the preparations of the slime polysaccharide component with titers of 1:64 to 1:256, determined in the immunodiffusion test, were obtained. In the precipitation test the slime polysaccharide component reacted with antisera from sick experimental animals, thus confirming the suggestion of its secretion in the process of the development of melioidosis infection.

[Nature of Pseudomonas pseudomallei antigens common to some species of microorganisms]. / K prirode antigenov Pseudomonas pseudomallei, obshchikh dlia nekotorykh vidov mikroorganizmov.

An antigen, common for the infective agents of glanders , tularemia, plague, pseudotuberculosis, cholera and brucellosis, has been obtained from the aqueous saline extract of P. pseudomallei by means of affinity chromatography on antibody sorbent. The isolated antigen has proved to be of a protein-polysaccharide-lipid nature, to have insignificant cathode mobility and to constitute a component of O-antigen. It has also been found to be antigenically related to the tissues of melioidosis-sensitive animals and localized in the surface structure of the bacterial cell.