The genome sequence of a non-capsular natural strain of A.Br.001/002 canSNP group isolated from permafrost in Yakutia, Russia.

We present the results of the whole-genome sequencing of a strain isolated from a permafrost sample collected in Yakutia, Russia. This strain was named YakM12. Phylogenetic analysis showed that YakM12 belongs to the canSNP group A.

Avirulence of a spontaneous Francisella tularensis subsp. mediasiatica prmA mutant.

Francisella tularensis, the causative agent of tularemia, is divided into three subspecies. Two of these, subspecies holarctica and tularensis, are highly pathogenic to humans and consequently relatively well studied. The third subspecies, mediasiatica, is rarely isolated and remains poorly studied.

New Research on the Genetic Diversity in Siberia.

Anthrax is a particularly dangerous infection of humans and ungulates caused by the Gram-positive spore-forming bacterium . The highly monomorphic and clonal species is commonly divided into three main lineages, A, B, and C, which in turn are divided into several canSNP groups. We report here a phylogenetic analysis based on the whole-genome sequence (WGS) data of fifteen strains isolated predominantly in Siberia or Central and Southern Russia.

Some Peculiarities of Anthrax Epidemiology in Herbivorous and Carnivorous Animals.

Anthrax is an especially dangerous zooanthroponosis caused by the Gram-positive spore-forming bacterium . A notable feature of this disease is the difference in susceptibility to it among different groups of animals. Anthrax primarily affects herbivorous ungulate mammals; they are easily infected, and their disease often leads to rapid, even sudden, death.

Using a Syrian (Golden) Hamster Biological Model for the Evaluation of Recombinant Anthrax Vaccines.

In this paper, we demonstrate that a Syrian hamster biological model can be applied to the study of recombinant anthrax vaccines. We show that double vaccination with recombinant proteins, such as protective antigen (PA) and fusion protein LF1PA4, consisting of lethal factor I domain (LF) and PA domain IV, leads to the production of high titers of specific antibodies and to protection from infection with the toxicogenic encapsulated attenuated strain 71/12. In terms of antibody production and protection, Syrian hamsters were much more comparable to guinea pigs than mice.

Russian isolates enlarge the known geographic diversity of Francisella tularensis subsp. mediasiatica.

Francisella tularensis, a small Gram-negative bacterium, is capable of infecting a wide range of animals, including humans, and causes a plague-like disease called tularemia-a highly contagious disease with a high mortality rate. Because of these characteristics, F. tularensis is considered a potential agent of biological terrorism.

[CONSTRUCTION AND PROPERTIES OF THE FRANCISELLA TULARENSIS VACCINE STRAIN WITHOUT ONE COPY OF THE IGLC GENE AND WITHOUT RECA GENE].

The live vaccine based on the Francisella tularensis subsp. holarctica vaccine strain 15 NIIEG line is used in Russia against tularemia. This vaccine is highly effective, but fairly unstable.

Magnetic field-enhanced sedimentation of nanopowder magnetite in water flow.

Sedimentation dynamics of magnetite (γ-Fe3O4) nanopowder (10-20 nm) in water in a gradient magnetic field Bmax=0.3 T, (dB/dz)max=0.13 T/cm was studied for different water flow speeds and starting particle concentrations (0.

[CITRULLINUREIDASE GENE DIVERSITY IN THE GENUS FRANCISELLA].

This work describes the results, of the in silico analysis of the genetic diversity of the citrullinureidase gene (ctu) in two species of bacteria of the genus Francisella: tularensis (ssp. tularensis, holarctica, mediasiatica, novicida) and philomiragia. The strains of the Central Asiatic subspecies possessing the citrullinureidase activity differ in the gene ctu from the ssp tularensis Schu by three nucleotide substitutions leading to two insignificant amino acid substitutions in the encoded polypeptide.

Functional characterization and biological significance of Yersinia pestis lipopolysaccharide biosynthesis genes.

In silico analysis of available bacterial genomes revealed the phylogenetic proximity levels of enzymes responsible for biosynthesis of lipopolysaccharide (LPS) of Yersinia pestis, the cause of plague, to homologous proteins of closely related Yersinia spp. and some other bacteria (Serratia proteamaculans, Erwinia carotovora, Burkholderia dolosa, Photorhabdus luminescens and others). Isogenic Y.

Biological properties and structure of the lipopolysaccharide of a vaccine strain of Francisella tularensis generated by inactivation of a quorum sensing system gene qseC.

A knockout mutant with a deletion in a quorum sensing system gene qseC was generated from the vaccine strain Francisella tularensis 15 by site-directed mutagenesis. The variant with the inactivated gene qseC differed from the parental strain in growth rate on solid nutrient medium but had the same growth dynamics in liquid nutrient medium. The mutation abolished almost completely the resistance of the vaccine strain to normal rabbit serum and its ability to survive in macrophages; in addition, the strain lost the residual virulence.

The subcutaneous inoculation of pH 6 antigen mutants of Yersinia pestis does not affect virulence and immune response in mice.

Two isogenic sets of Yersinia pestis strains were generated, composed of wild-type strains 231 and I-1996, their non-polar pH 6(-) mutants with deletions in the psaA gene that codes for its structural subunit or the whole operon, as well as strains with restored ability for temperature- and pH-dependent synthesis of adhesion pili or constitutive production of pH 6 antigen. The mutants were generated by site-directed mutagenesis of the psa operon and subsequent complementation in trans. It was shown that the loss of synthesis or constitutive production of pH 6 antigen did not influence Y.

Structural diversity and endotoxic activity of the lipopolysaccharide of Yersinia pestis.

The endotoxic activity of the lipopolysaccharides (LPS) with defined chemical structure from Yersinia pestis strains of various subspecies differing in their epidemic potential was studied. The LPS of two strains of Y. pestis ssp.

Relationship of the lipopolysaccharide structure of Yersinia pestis to resistance to antimicrobial factors.

Disruption of lipopolysaccharide (LPS) biosynthesis genes in an epidemiologically significant Yersinia pestis strain showed that the ability to synthesize the full inner core of the LPS is crucial for resistances to the bactericidal action of antimicrobial peptides and to complement-mediated serum killing. Resistance to polymyxin B also requires a high content of the cationic sugar, 4-amino-4-deoxy-L-arabinose, in lipid A.

Effect of deletion of the lpxM gene on virulence and vaccine potential of Yersinia pestis in mice.

Yersinia pestis undergoes an obligate flea-rodent-flea enzootic life cycle. The rapidly fatal properties of Y. pestis are responsible for the organism's sustained survival in natural plague foci.

[Anthrax: early steps of the intracellular stage of infection development].

It was shown that spore germination of different Bacillus anthracis strains in macrophage-like cells J774A.1 depended on the genotype of the strains. The virulent B.

Intraspecies and temperature-dependent variations in susceptibility of Yersinia pestis to the bactericidal action of serum and to polymyxin B.

Lipopolysaccharide (LPS) structure impacts the bactericidal action of cationic peptides, such as polymyxin B (PMB), and sensitivity to killing by normal human serum (NHS). Cultivation of different subspecies strains of Yersinia pestis isolated from unrelated geographic origins at various temperatures (mammals, 37 degrees C; fleas, 25 degrees C; or winter hibernation, 6 degrees C) affects LPS composition and structure. We tested the susceptibilities of various strains of Y.

Temperature-dependent variations and intraspecies diversity of the structure of the lipopolysaccharide of Yersinia pestis.

Yersinia pestis spread throughout the Americas in the early 20th century, and it occurs predominantly as a single clone within this part of the world. However, within Eurasia and parts of Africa there is significant diversity among Y. pestis strains, which can be classified into different biovars (bv.

[Specific features of minute structure of Mycobacteria cultured in murine macrophages].

In experimentally infected murine peritoneal macrophages and murine macrophage-like cells J-774 with different pathogen strains of tuberculos'is, Mycobacterium tuberculosis (MBT) underwent significant morphofunctional changes. In phagocytosis, several live and mycobacteria conventionally referred by the authors to as morphotype I cells come from the environment to the macrophage. Of them, single young and intact mycobacteria are able to multiply and form at 2-3 generations morphotype II microcolonies from 3-9 mycobacteria or more in the phasolysosomes within the first 24 hours after infection.

[Effect of fosfidomycin on development of various infections in mice].

Antibiotic fosmidomycin will know as inhibitor of the nonmevalonate pathway of isoprenoid biosynthesis and as possible antimalarial drug, was shown to possess a certain protective effect on mice experimentally infected with tularemia, tiphus or coli-septicemia. Positive effect on mice with chronic form of tuberculosis was not observed when the animals were given 1 mg of fosmidomycin per capita twice a day. Under oxidative conditions an ESR signal of long living nitroxil free radicals were registered in the water solution of fosmidomycin.

[Immunomodulatory properties of 2-C-methyl-D-erythritol-2,4-cyclopyrophosphate and search for its new derivatives].

A strong immunomodulatory effect of 2-C-methyl-D-erythritol-2,4-cyclopyrophosphate (MEC) responsible for the survival of bacteria was shown on isolated macrophages and in experimental infections in mice (typhoid and tularemia). Derivatives of MEC were found by 1H-NMR spectroscopy under stress conditions in colorless mutants of the bacteria and isolated to be subsequently purified and used for modulation of the immune system of animals.