[Characteristics of isogenic variants of Bacillus anthracis with various content of virulence plasmids].

AIM: Production and characteristics by main cultural-morphologic and antigenic properties of isogenic variants Bacillus anthracis, that differ by the presence of virulence plasmids. MATERIALS AND METHODS: B. anthracis 81/1, 575/122 virulent and B. anthracis STI, 55, Sterne vaccine strains were used in the study. Isogenic variants, that differ by the presence of virulence plasmids, were obtained by temperature elimination of plasmids, as well as during cultivation of anthrax strains in medium with kanamycin. The strains were characterized by cultural-morphologic, biochemical properties. The presence of virulence plasmids was determined by polymerase chain reaction method. Antigenic properties were studied in immune diffusion reaction with growing cultures with sera against protective antigen and S-layer proteins, electrophoresis, immune blotting. RESULTS: Isogenic variants were produced from virulent strains B. anthracis 81/1, 575/122 and vaccine strains STI, 55, Sterne: mono-plasmid toxin-producing (81/1 R01, 575/122 R01) and capsule-containing (81/1 R02, 575/122 R02), and plasmid-less (81/1 R00, 575/122 R00, STI R00, 55 R00, Sterne R00), that differ by the presence of virulence plasmids. Strains had typical cultural-morphologic properties, differed by biochemical and antigenic properties. Cultural filtrates of toxin-producing strains had protein of anthrax toxin; plasmid-less strains--had proteins, that had molecular masses corresponding to molecular masses of S-layer EA1 and Sap proteins. CONCLUSION: These strains may be used to study variability and proteomic analysis of anthrax causative agent, as well as for isolation of antigens with the aim of evaluating their immune diagnostic significance.

[Epidemiologic situation of West Nile fever in Russia in 2010].

Problem of tropical arbovirus infection--West Nile fever (WNF)--spread in Russian Federation is discussed. Biology of WNF is discussed, WNF sources and reservoir are characterized. WNF outbreaks in Russia during the past 2 decades are presented in detail. Outbreaks of different years, possible causes and epidemiology are discussed. Features of WNF clinical course during various outbreaks and WNF diagnostic problems are presented.

[Pathogenicity of West Nile virus: molecular markers].

The review describes the phenotypic properties, structure, and expression pattern of West Nile virus genome (Flaviviridae, Flavivirus, Japanese encephalitis antigenic complex), as well as the clinical picture and pathogenesis of its etiologically related disease West Nile fever. It also analyzes the available data on the impact of genetic mutations in the genome on the biological properties of the virus.

[Species-specific sera against surface antigens of Bacillus anthracis strains].

The species-related specificity of sera against 94-KD proteins isolated from culture filtrates of B. anthracis strains with different levels of virulence plasmids was studied to determine whether they might be used to identify the pathogen of anthrax. Sera against fractions 1 of culture filtrates of B. anthracis strains CTI (pXO1+ pXO2-), 81/1TR (pXO1- pXO2-), Davies (pXO1- pXO) separated by gel chromatography on Sephacryl S-300 were examined. In the gel immunodiffusion test with growing cultures, the sera exhibited non-identical antigens and differed in the presence of antibodies to antigens of related bacilli. The sera against fractions 1 of culture filtrates of toxin-producing and plasmidless strains displayed antigens produced only by B. anthracis strains into nutrient agar. Electroimmunotransblotting revealed that they contained antibodies mainly to 94-kD proteins and failed to react with B. cereus proteins with a molecular weight of 94 kD and with B. thuringiensis proteins with a molecular weight of 97 kD, which were extracted from autonomous cells. In the immunofluorescence test, immunoglobulins of sera against fractions 1 of culture filtrates of three strains stained autonomous cells and spores of 23 B. anthracis strains with different levels of virulence plasmids. In working dilutions, they did not react with antigens of 18 strains of related bacilli, which presents a possibility of using them for species identification of B. anthracis.

[Identification of the agents of coccidioidomycosis using polymerase chain reaction].

Two pairs of primers for diagnosis of coccidioidomycosis using the method of PCR were constructed. One pair was used for identification of the two species of Coccidioides (C. immitis and C. posadasil) on the basis of MBP-1 gene. The other pair was chosen on the basis of SOWgp82 gene, which encodes an immunodominant, spherule outer wall glycoprotein for detecting only C. posadasii. The used primers allowed the agents of coccidioidomycosis to be detected using PCR with high sensitivity and specificity. The effective method of isolation of fungus DNA from soil contaminated with arthroconidia of Coccidioides spp. was developed. It includes guanidinthiocyanate-phenol-chloroform deproteinization followed by DNA purification using nuclear sorption.

[Induction of Bacillus anthracis hemolytic activity with the use of Myxococcus xanthus].

The development of a new method for the induction of the B. anthracis hemolytic activity with the use of M. xanthus and the differentiation of pure cultures of the causative agent of anthrax from those contaminated with myxobacteria is presented. To demonstrate the induction of the hemolytic acivity of B. anthracis with the use of M. xanthus, conditions for the symbiosis of B. anthracis cells STI, exhibiting no hemolytic activity, with M. xanthus non-hemolytic cells were created by mixing them and inoculating the symbiotic biomass on the surface of blood agar.

[Venezuelan equine encephalitis: state-of-the-art].

The paper provides the currently available data on the global prevalence of Venezuelan equine encephalitis (VEE), its epidemiology, clinical picture, and specific prevention in human beings. It also discussed the problem of potential use of the causative agent of VEE as a subject of bioterrorism.

[The effect of heterologous bacilli on the infectious process in anthrax in an experiment]. / Vliianie geterologicheskikh batsill na infektsionnyi protsess pri sibirskoi iazve v éksperimente.

The possibility of the survival of guinea pigs after the simultaneous administration of different doses of Bacillus anthracis virulent strain 81/1 in combination with both B. anthracis vaccine strain STI and heterologous bacilli (B. subtilis strain PAC) has been experimentally shown. On the basis of the results of these experiments suggestion has been made that the "survival phenomenon" is the process involving the lysosomal systems of polymorphonuclear and mononuclear phagocytes.

[The characteristics of the interaction of Bacillus anthracis with host phagocytes in relation to the plasmid spectrum of the causative agent]. / Osobennosti vzaimodeistviia Bacillus anthracis s fagotsitami khoziaina v zavisimosti ot plazmidnogo spektra vozbuditelia.

The study revealed that after the intraperitoneal inoculation of spores of B. anthracis strains with different plasmid composition into guinea pigs the active germination of the spores both outside and inside the cells of the host occurred as early as on hour 2 of their interaction with the macroorganism. The further fate of the infective agent and the character of its interaction with peritoneal exudate cells depended on the plasmid composition of the bacilli. Thus, the presence of toxin-formation plasmid PXO1 and capsule-formation plasmid PXO2 in B. anthracis permitted the successful adaptation of these bacilli to the conditions of the macroorganism, while the absence of such plasmids made them nonviable in this environment. The presence of plasmid PXO1 in B. anthracis permitted the manifestation of their cytopathic effort on the cells and the presence of plasmid PXO2 only gave the bacilli incomplete protection from phagocytosis.

[A species-specific DNA probe for identifying toxic strains of anthrax pathogens]. / Vidospetsificheskii DNK-zond dlia identifikatsii toksigennykh shtammov vozbuditelia sibirskoi iazvy.

On the plasmid DNA pOX01 of the anthrax pathogen two BamHI fragments were localized which facilitate detection of the Bacillus anthracis strains carrying pXO1 replicon. These fragments, after complete hydrolysis of plasmid DNA by HindIII, were cloned on the vector plasmids pUC19 and pBR322 by the "shot-gun" method in Escherichia coli cells. It is shown that the 900 bp BamHI/HindIII fragment from the pZAT1 recombinant plasmid has an ability for specific hybridization with DNA of toxigenic strains of B. anthracis and could be used as species-specific anthracic DNA probe which identifies toxigenic strains of the anthrax pathogen differentiating it from the other species of Bacillus genus as well as from the bacteria of other taxonomy groups.

[Dimorphism in the fungus Coccidioides immitis Rixford et Gilchrist under the action of saprophytic bacilli]. / Dimorfizm griba Coccidioides immitis Rixford et Gilchrist pod vozdeistviem batsill-saprofitov.

It is shown that there are specific substances produced and secreted into the environment by saprotrophic bacilli. These inhibit the growth of the coccidioidal fungus in its mycelial form and some cells are converted into the yeast form, which leads to the destruction of the fungi (in natural environment) or, if the conditions allow, to their growth in the yeast form. This phenomenon, existence of a large amount of bacilli antagonistic to Coccidioides immitis, may be one of reasons why the latter has not been isolated so far from the soil in the territory of the USSR.

Immunobiological characteristic of antigens from the parasitic phase of Coccidiodes immitis.

The possibility of obtaining serologically active antigens from tissue spherules extracted from the lungs of albino mice infected with C. immitis has been demonstrated. Unlike the method of obtaining spherules in vitro, the accumulation of sufficient quantities of tissue spherules does not involve special difficulties. To obtain more pure and specific antigens from crude tissue spherules material, chromatographic separation on a column with Sephadex G-100 is recommended. Antigens obtained from the spherules in vivo have been found to be more specific and active in serological and allergic reactions in comparison with the corresponding antigens from the mycelial form or from spherules in vitro and can be used in the diagnosis of coccidioidosis as well as in the study of the mechanism of cellular immunity.