Peptidoglycan-Free Bacterial Ghosts Confer Enhanced Protection against Infection.

To develop a modern plague vaccine, we used hypo-endotoxic   bacterial ghosts (BGs) with combinations of genes encoding the bacteriophage ɸX174 lysis-mediating protein E and/or holin-endolysin systems from λ or L-413C phages. Expression of the protein E gene resulted in the BGs that retained the shape of the original bacterium. Co-expression of this gene with genes coding for holin-endolysin system of the phage L-413C caused formation of structures resembling collapsed sacs.

Draft Genome Sequences of Six Yersinia kristensenii Strains.

Yersinia kristensenii is one of the Yersinia enterocolitica-like bacterial species, which are considered nonpathogenic to humans. In this work, we reported the draft genome sequences of six Yersinia kristensenii strains. These draft genomes will help to better characterize Yersinia kristensenii at the genomic level.

Complete Genome Assembly of Yersinia pestis subsp. bv. Medievalis SCPM-O-B-6530, a Proline-Dependent Strain Isolated from the Central-Caucasian High-Mountain Plague Focus in Kabardino-Balkar Republic (Russia).

We report the complete genome assembly of Yersinia pestis subsp. bv. Medievalis SCPM-O-B-6530, a strain belonging to the most ancient phylogenetic group (group 2.

Lipopolysaccharide of the Complex.

Lipopolysaccharide (LPS), localized in the outer leaflet of the outer membrane, serves as the major surface component of the Gram-negative bacterial cell envelope responsible for the activation of the host's innate immune system. Variations of the LPS structure utilized by Gram-negative bacteria promote survival by providing resistance to components of the innate immune system and preventing recognition by TLR4. This review summarizes studies of the biosynthesis of Yersinia pseudotuberculosis complex LPSs, and the roles of their structural components in molecular mechanisms of yersiniae pathogenesis and immunogenesis.

Whole-Genome Assembly of Yersinia pestis 231, the Russian Reference Strain for Testing Plague Vaccine Protection.

We report the whole-genome sequence of subsp. bv. Antiqua strain 231 belonging to the 0.

Outer Membrane Vesicles as Potential Vaccine Candidates in Protecting against Plague.

Despite the relatively low incidence of plague, its etiological agent, , is an exceptional epidemic danger due to the high infectivity and mortality of this infectious disease. Reports on the isolation of drug-resistant strains indicate the advisability of using asymmetric responses, such as phage therapy and vaccine prophylaxis in the fight against this problem. The current relatively effective live plague vaccine is not approved for use in most countries because of its ability to cause heavy local and system reactions and even a generalized infectious process in people with a repressed immune status or metabolic disorders, as well as lethal infection in some species of nonhuman primates.

Structure elucidation and gene cluster characterization of the O-antigen of Yersinia kristensenii С-134.

Mild acid degradation of the lipopolysaccharide of Yersinia kristensenii C-134 afforded a glycerol teichoic acid-like O-polysaccharide, which was studied by sugar analysis, O-deacetylation and dephosphorylation along with 1D and 2D NMR spectroscopy. The following structure of the O-polysaccharide was established: This structure is related to those of other Y. kristensenii O-polysaccharides studied earlier.

Six Whole-Genome Assemblies of Yersinia pestis subsp. microtus bv. ulegeica (Phylogroup 0.PE5) Strains Isolated from Mongolian Natural Plague Foci.

Here, we report the draft genome sequences of six subsp. bv. ulegeica strains isolated from the territory of Mongolia and representing the 0.

Full structure and insight into the gene cluster of the O-specific polysaccharide of Yersinia intermedia H9-36/83 (O:17).

Lipopolysaccharide was isolated from bacteria Yersinia intermedia H9-36/83 (O:17) and degraded with mild acid to give an O-specific polysaccharide, which was isolated by GPC on Sephadex G-50 and studied by sugar analysis and 1D and 2D NMR spectroscopy. The polysaccharide was found to contain 3-deoxy-3-[(R)-3-hydroxybutanoylamino]-d-fucose (d-Fuc3NR3Hb) and the following structure of the heptasaccharide repeating unit was established: The structure established is consistent with the gene content of the O-antigen gene cluster. The O-polysaccharide structure and gene cluster of Y.

Nine Whole-Genome Assemblies of subsp. bv. Altaica Strains Isolated from the Altai Mountain Natural Plague Focus (No. 36) in Russia.

We report here the draft genome sequences of nine subsp. bv. Altaica strains isolated from the Altai Mountain plague focus (no.

Eight Whole-Genome Assemblies of subsp. bv. caucasica Isolated from the Common Vole () Plague Focus in Dagestan, Russia.

We here report the draft genome sequences of 8 subsp. bv. caucasica strains isolated from the East Caucasian (previous name, Dagestan) mountain focus (no.

Two Isoforms of Yersinia pestis Plasminogen Activator Pla: Intraspecies Distribution, Intrinsic Disorder Propensity, and Contribution to Virulence.

It has been shown previously that several endemic Y. pestis isolates with limited virulence contained the I259 isoform of the outer membrane protease Pla, while the epidemic highly virulent strains possessed only the T259 Pla isoform. Our sequence analysis of the pla gene from 118 Y.

Yersinia pestis Caf1 Protein: Effect of Sequence Polymorphism on Intrinsic Disorder Propensity, Serological Cross-Reactivity and Cross-Protectivity of Isoforms.

Yersinia pestis Caf1 is a multifunctional protein responsible for antiphagocytic activity and is a key protective antigen. It is generally conserved between globally distributed Y. pestis strains, but Y.

Effect of natural polymorphism on structure and function of the Yersinia pestis outer membrane porin F (OmpF protein): a computational study.

The Yersinia pestis outer membrane porin F (OmpF) is a transmembrane protein located in the outer membrane of this Gram-negative bacterium which is the causative agent of plague, where it plays a significant role in controlling the selective permeability of the membrane. The amino acid sequences of OmpF proteins from 48 Y. pestis strains representing all currently available phylogenetic groups of this Gram-negative bacterium were recently deduced.

Polymorphism of the Cysteine Protease YopT from Yersinia pestis.

Antibiotic therapy of plague is hampered by the recent isolation of Yersinia pestis strain resistant to all of antibiotics recommended for cure. This has constrained a quest for new antimicrobials taking aim at alternative targets. Recently Y.

Nineteen Whole-Genome Assemblies of Yersinia pestis subsp. microtus, Including Representatives of Biovars caucasica, talassica, hissarica, altaica, xilingolensis, and ulegeica.

The etiologic agent of plague, Yersinia pestis, includes two subspecies, of which Y. pestis subsp. microtus contains the strains that cause only occasional diseases in humans that are not accompanied by human-to-human transmission.

Revision of the O-polysaccharide structure of Yersinia pseudotuberculosis O:1a; confirmation of the function of WbyM as paratosyltransferase.

An O-polysaccharide was isolated by mild acid degradation at pH 4.5 of the long-chain lipopolysaccharide of Yersinia pseudotuberculosis PB1 (serotype O:1a) and studied using 2D NMR spectroscopy. It was found to contain two uncommon monosaccharides: paratose (3,6-dideoxy-d-ribo-hexose, Par) in the furanose form and 6-deoxy-d-manno-heptose (d-6dmanHep).

Identification of the lipopolysaccharide core of Yersinia pestis and Yersinia pseudotuberculosis as the receptor for bacteriophage φA1122.

φA1122 is a T7-related bacteriophage infecting most isolates of Yersinia pestis, the etiologic agent of plague, and used by the CDC in the identification of Y. pestis. φA1122 infects Y.

Amino acid and structural variability of Yersinia pestis LcrV protein.

The LcrV protein is a multifunctional virulence factor and protective antigen of the plague bacterium and is generally conserved between the epidemic strains of Yersinia pestis. We investigated the diversity in the LcrV sequences among non-epidemic Y. pestis strains which have a limited virulence in selected animal models and for humans.

Revision of the O-polysaccharide structure of Yersinia pseudotuberculosis O:1b.

The O-polysaccharide of Yersinia pseudotuberculosis O:1b was reinvestigated using (1)H and (13)C NMR spectroscopy, and the anomeric configuration of the mannose residue at the branching point was revised. The following is the revised structure of the O-polysaccharide: [structure: see the text] where Par stands for 3,6-dideoxy-D-ribo-hexose (paratose). The revised structure of the main chain is shared by the O-polysaccharide of Y.

Genotyping and phylogenetic analysis of Yersinia pestis by MLVA: insights into the worldwide expansion of Central Asia plague foci.

Background: The species Yersinia pestis is commonly divided into three classical biovars, Antiqua, Medievalis, and Orientalis, belonging to subspecies pestis pathogenic for human and the (atypical) non-human pathogenic biovar Microtus (alias Pestoides) including several non-pestis subspecies. Recent progress in molecular typing methods enables large-scale investigations in the population structure of this species. It is now possible to test hypotheses about its evolution which were proposed decades ago.

Structure of the O-antigen of Yersinia pseudotuberculosis O:4a revised.

The O-specific polysaccharide was isolated by mild acid degradation of the lipopolysaccharide of Yersinia pseudotuberculosis O:4a and studied by NMR spectroscopy, including 2D ROESY and (1)H, (13)C HMBC experiments. The following structure of the pentasaccharide repeating unit of the polysaccharide was established, which differs from the structure reported earlier [Gorshkova, R. P.

Structure of the O-polysaccharide of Yersinia pseudotuberculosis O:2b.

The O-polysaccharide was isolated by hydrolysis of the lipopolysaccharide of Yersinia pseudotuberculosis O:2b, and studied by 1D and 2D NMR spectroscopy. The following structure of the polysaccharide was established: alpha-Abep. 1-->3.

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.