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119 results on '"Prokhorov, N. A."'

18. OPTIMIZATION OF RADIATION DOSES TO PATIENTS IN X-RAY DIAGNOSTICS

Author

Okhrimenko, Sergei E., primary, Ilin, L. A., additional, Korenkov, I. P., additional, Morozov, S. P., additional, Birukov, A. P., additional, Gombolevskiy, V. A., additional, Prokhorov, N. I., additional, Lantukh, Z. A., additional, Rizhov, S. A., additional, Soldatov, I. V., additional, and Fomin, A. A., additional

Published
2019
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24. Lifestyle and health of students

Author

Ermakova, Nina A., primary, Melnichenko, P. I., additional, Prokhorov, N. I., additional, Timoshenko, K. T., additional, Matveev, A. A., additional, Kostina, E. V., additional, and Minnibaev, T. Sh., additional

Published
2019
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34. Variations in O-antigen biosynthesis and O-acetylation associated with altered phage sensitivity in Escherichia coli 4s

Author

Knirel Y., Prokhorov N., Shashkov A., Ovchinnikova O., Zdorovenko E., Liu B., Kostryukova E., Larin A., Golomidova A., and Letarov A.

Abstract

© 2015, American Society for Microbiology. The O polysaccharide of the lipopolysaccharide (O antigen) of Gram-negative bacteria often serves as a receptor for bacteriophages that can make the phage dependent on a given O-antigen type, thus supporting the concept of the adaptive significance of the O-antigen variability in bacteria. The O-antigen layer also modulates interactions of many bacteriophages with their hosts, limiting the access of the viruses to other cell surface receptors. Here we report variations of O-antigen synthesis and structure in an environmental Escherichia coli isolate, 4s, obtained from horse feces, and its mutants selected for resistance to bacteriophage G7C, isolated from the same fecal sample. The 4s O antigen was found to be serologically, structurally, and genetically related to the O antigen of E. coli O22, differing only in side-chain α-D-glucosylation in the former, mediated by a gtr locus on the chromosome. Spontaneous mutations of E. coli 4s occurring with an unusually high frequency affected either O-antigen synthesis or O-acetylation due to the inactivation of the gene encoding the putative glycosyltransferase WclH or the putative acetyltransferase WclK, respectively, by the insertion of IS1-like elements. These mutations induced resistance to bacteriophage G7C and also modified interactions of E. coli 4s with several other bacteriophages conferring either resistance or sensitivity to the host. These findings suggest that O-antigen synthesis and O-acetylation can both ensure the specific recognition of the O-antigen receptor following infection by some phages and provide protection of the host cells against attack by other phages.

Published
2015

35. Genomic sequencing and biological characteristics of a novel Escherichia Coli bacteriophage 9g, a putative representative of a new siphoviridae genus

Author

Kulikov E., Golomidova A., Letarova M., Kostryukova E., Zelenin A., Prokhorov N., and Letarov A.

Subjects
Feces, viruses, Modified DNA base, Pseudolysogeny, Horse, Bacteriophage genome
Abstract

© 2014 by the authors; licensee MDPI, Basel, Switzerland. Bacteriophage 9g was isolated from horse feces using Escherichia coli C600 as a host strain. Phage 9g has a slightly elongated capsid 62 × 76 nm in diameter and a non-contractile tail about 185 nm long. The complete genome sequence of this bacteriophage consists of 56,703 bp encoding 70 predicted open reading frames. The closest relative of phage 9g is phage PhiJL001 infecting marine alpha-proteobacterium associated with Ircinia strobilina sponge, sharing with phage 9g 51% of amino acid identity in the main capsid protein sequence. The DNA of 9g is resistant to most restriction endonucleases tested, indicating the presence of hypermodified bases. The gene cluster encoding a biosynthesis pathway similar to biosynthesis of the unusual nucleoside queuosine was detected in the phage 9g genome. The genomic map organization is somewhat similar to the typical temperate phage gene layout but no integrase gene was detected. Phage 9g efficiently forms stable associations with its host that continues to produce the phage over multiple passages, but the phage can be easily eliminated via viricide treatment indicating that no true lysogens are formed. Since the sequence, genomic organization and biological properties of bacteriophage 9g are clearly distinct from other known Enterobacteriaceae phages, we propose to consider it as the representative of a novel genus of the Siphoviridae family.

Published
2014

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