Bacteriophage content of M49 strains of Streptococcus pyogenes

Bacteriophages are common autonomous migrating mobile genetic elements in group A Streptococcus (GAS) and are often associated with the carriage of various virulence genes, including toxins, mitogens and enzymes. Two collections of GAS type M49 strains isolated from invasive (22 strains) and noninvasive (16 strains) clinical cases have been studied for the presence of phage and phage-associated virulence genes. All the GAS strains carried from at least two to six phage genomes as determined by the number of known phage integrase genes found. A sampling of the invasive M49 strains showed that they belonged to the same multilocus sequence typing type, carried two specific integrase genes ( int 5 and int 7), and contained the toxin genes spe A, spe H and spe I. Other invasive strains lacking this gene profile carried the prophage integrating in mutL–mutS region and inducing the 'mutator' phenotype. We suggest that this specific phage-related virulence gene constellation might be an important factor increasing M49 GAS pathogenicity.     

Immunogenicity of modified by dextran recombinant fragment of Bac protein of group B streptococci

Opportunity to increase of immunogenicity of recombinant polypeptide P6 constructed on the basis of surface protective Bac protein by its chemical conjugation with dextran (D) 40 was studied. 3 preparations with different quantity of protein and polysaccharide components were obtained. Their testing with standard serum showed that antigenic determinants of the polypeptide were preserved although partly enclosed and structure of antigenic determinants did not significantly changed. On the model of subcutaneous immunization of mice it has been shown that two preparations--P6D2 and P6D3--have improved immunological characteristics. Conjugation of polypeptide P6 with dextran let to increase of immune response to P6 and affinity of P6-specific antibodies. Injection of nonconjugated P6 and dextran mixture showed that free dextran is not immunogenic and it suppress synthesis of P6-specific antibodies without effect on their affinity. Intranasal administration of nonconjugated P6 did not lead to P6-specific IgG in serum. After conjugation with dextran polypeptide P6 was recognized as an antigen and stimulated production of small quantity of antibodies. Technological process of chemical binding of protein antigen with polysaccharides, which let to regulate protein and polysaccharide components ratio, can be the effective method to increase immunogenicity of recombinant polypeptides.     

Comparative sensitivity of cholinesterases in vertebrates and invertebrates to highly specific organophosphorus inhibitors,diisopropyl fluorophosphate (DFP) and (2-ethoxymethyl phosphoryl thioethyl) ethyl (methyl) sulphonium sulphomethylate (GD-42)

The review presents the data on a comparative reactivity of 68 cholinesterase preparations from various organs and tissues in a number of vertebrates and invertebrates based on the sensitivity to the two highly specific and most studied organophosphorus inhibitors, diisopropyl fluorophosphates (DFP) and (2-ethoxymethyl phosphoryl thioethyl) ethyl (methyl) sulphonium sulphomethylate (GD-42). An analysis of the data obtained suggests a great diversity of enzymologic characteristics of cholinesterase preparations in vertebrates and invertebrates observed even in closely related enzymes in animals at virtually the same level of evolutionary development.     

Evaluation of Different Reference Based Annotation Strategies Using RNA-Seq – A Case Study in Drososphila pseudoobscura

RNA-Seq is a powerful tool for the annotation of genomes, in particular for the identification of isoforms and UTRs. Nevertheless, several software tools exist and no standard strategy to obtain a reliable annotation is yet established. We tested different combinations of the most commonly used reference-based alignment tools (TopHat, GSNAP) in combination with two frequently used reference-based assemblers (Cufflinks, Scripture) and evaluated the potential of RNA-Seq to improve the annotation of Drosophila pseudoobscura. While GSNAP maps a higher proportion of reads, TopHat resulted in a more accurate annotation when used in combination with Cufflinks. Scripture had the lowest sensitivity. Interestingly, after subsampling to the same coverage for GSNAP and TopHat, we find that both mappers have similar performance, implying that the advantage of TopHat is mainly an artifact of the lower coverage. Overall, we observed a low concordance among the different approaches tested both at junction and isoform levels. Using data from both sexes of two adult strains of D. pseudoobscura we detected alternative splicing for about 30% of the FlyBase multiple-exon genes. Moreover, we extended the boundaries for 6523 genes (about 40%). We annotated 669 new genes, 45% of them with splicing evidence. Most of the new genes are located on unassembled contigs, reflecting their incomplete annotation. Finally, we identified 99 additional new genes that are not represented in the current genome contigs of D. pseudoobscura, probably due to location in genomic regions that are difficult to assemble (e.g. heterochromatic regions).     

Reversible lupininin inhibitors of cholinesterases of mammalian blood and of optical ganglia of individuals of the commander squid Berryteuthis magister from different zones of species areal

Arylsulfoesters and carbonic lupinin esters are studied for the first time as reversible inhibitors of mammalian blood cholinesterases. Studied in detail is sensitivity of cholinesterases to mono- and bislupinin inhibitors in Commander squid individuals from different habitation zones.     

Clinical strains of <Emphasis Type="Italic">Streptococcus agalactiae</Emphasis> carry two different variants of pathogenicity island XII

Streptococcus agalactiae or Group B streptococci (GBS) are a common cause of serious diseases of newborns and adults. GBS pathogenicity largely depends on genes located on the accessory genome including several pathogenicity islands (PAI). The present paper is focused on the structure and molecular epidemiological analysis of one of the GBS pathogenicity islands—the pathogenicity island PAI XII (Glaser et al. Mol Microbiol 45(6):1499–1513, 2002). This PAI was found to be composed of three different mobile genetic elements: a composite transposon (PAI-C), a genomic islet (PAI-B), and a pathogenicity island associated with gene sspB1 (PAI-A). PAI-A in GBS has a homolog——PAI-A1 with similar, but a different genetic constellation. PCR-based analysis of GBS collections from different countries revealed that a strains lineage with PAI-A is less common than PAI-A1 and was determined to be present only among the strains obtained from Russia. Our results suggest that PAI-A and PAI-A1 have the same progenitor, which evolved independently and appeared in the GBS genome as separate genetic events. Results of this study reflect specific geographical distribution of the GBS strains with the mobile genetic element under study.     

Destruction of a Bacterial Biofilm with an Electrochemically Activated Solution

Biophysics - The action of electrochemically activated water on the fine structure of biofilms formed by the plankton forms of lactic acid bacteria and E. coli was investigated. Bacterial biofilms...