23 research outputs found

    Trends of the major porin gene (ompF) evolution

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    OmpF is one of the major general porins of Enterobacteriaceae that belongs to the first line of bacterial defense and interactions with the biotic as well as abiotic environments. Porins are surface exposed and their structures strongly reflect the history of multiple interactions with the environmental challenges. Unfortunately, little is known on diversity of porin genes of Enterobacteriaceae and the genus Yersinia especially. We analyzed the sequences of the ompF gene from 73 Yersinia strains covering 14 known species. The phylogenetic analysis placed most of the Yersinia strains in the same line assigned by 16S rDNA-gyrB tree. Very high congruence in the tree topologies was observed for Y. enterocolitica, Y. kristensenii, Y. ruckeri, indicating that intragenic recombination in these species had no effect on the ompF gene. A significant level of intra- and interspecies recombination was found for Y. aleksiciae, Y. intermedia and Y. mollaretii. Our analysis shows that the ompF gene of Yersinia has evolved with nonrandom mutational rate under purifying selection. However, several surface loops in the OmpF porin contain positively selected sites, which very likely reflect adaptive diversification Yersinia to their ecological niches. To our knowledge, this is a first investigation of diversity of the porin gene covering the whole genus of the family Enterobacteriaceae. This study demonstrates that recombination and positive selection both contribute to evolution of ompF, but the relative contribution of these evolutionary forces are different among Yersinia species

    Molecular Evolution of the Yersinia Major Outer Membrane Protein C (OmpC)

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    The genus Yersinia includes species with a wide range of eukaryotic hosts (from fish, insects, and plants to mammals and humans). One of the major outer membrane proteins, the porin OmpC, is preferentially expressed in the host gut, where osmotic pressure, temperature, and the concentrations of nutrients and toxic products are relatively high. We consider here the molecular evolution and phylogeny of Yersinia ompC. The maximum likelihood gene tree reflects the macroevolution processes occurring within the genus Yersinia. Positive selection and horizontal gene transfer are the key factors of ompC diversification, and intraspecies recombination was revealed in two Yersinia species. The impact of recombination on ompC evolution was different from that of another major porin gene, ompF, possibly due to the emergence of additional functions and conservation of the basic transport function. The predicted antigenic determinants of OmpC were located in rapidly evolving regions, which may indicate the evolutionary mechanisms of Yersinia adaptation to the host immune system

    Trends of the Major Porin Gene (ompF) Evolution: Insight from the Genus Yersinia

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    OmpF is one of the major general porins of Enterobacteriaceae that belongs to the first line of bacterial defense and interactions with the biotic as well as abiotic environments. Porins are surface exposed and their structures strongly reflect the history of multiple interactions with the environmental challenges. Unfortunately, little is known on diversity of porin genes of Enterobacteriaceae and the genus Yersinia especially. We analyzed the sequences of the ompF gene from 73 Yersinia strains covering 14 known species. The phylogenetic analysis placed most of the Yersinia strains in the same line assigned by 16S rDNA-gyrB tree. Very high congruence in the tree topologies was observed for Y. enterocolitica, Y. kristensenii, Y. ruckeri, indicating that intragenic recombination in these species had no effect on the ompF gene. A significant level of intra- and interspecies recombination was found for Y. aleksiciae, Y. intermedia and Y. mollaretii. Our analysis shows that the ompF gene of Yersinia has evolved with nonrandom mutational rate under purifying selection. However, several surface loops in the OmpF porin contain positively selected sites, which very likely reflect adaptive diversification Yersinia to their ecological niches. To our knowledge, this is a first investigation of diversity of the porin gene covering the whole genus of the family Enterobacteriaceae. This study demonstrates that recombination and positive selection both contribute to evolution of ompF, but the relative contribution of these evolutionary forces are different among Yersinia species

    Location of positively selected sites in OmpF porins of <i>Yersinia</i>.

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    <p>Group VII-<i>Y. enterocolitica</i> WA220; Group XIII-<i>Y. intermedia</i> 1948; Group IX-<i>Y. frederiksenii</i> 4648; Group I-<i>Y. intermedia</i> ATCC 29909; Group X-<i>Y. kristensenii</i> 5868; Group VIII-<i>Y. pseudotuberculosis</i> IP 31758. Sites that show positive selection (P<0.05) are depicted as yellow spheres and (P<0.01)-as red spheres.</p

    Phylogenetic relationships among 16S rDNA-<i>gyrB</i> sequences of <i>Yersinia</i>.

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    <p>The unrooted dendrogram was generated using neighbour-joining algorithm. The evolutionary distances were computed using the Kimura 2-parameter method and are expressed in number of base substitutions per site. The percentages of replicate trees in which the associated taxa clustered together in the bootstrap test are shown in nodes.</p

    Phylogenetic relationships among <i>ompF</i> sequences of <i>Yersinia</i>.

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    <p>The unrooted dendrogram was generated using neighbour-joining algorithm. The evolutionary distances were computed using the Kimura 2-parameter method and are expressed in number of base substitutions per site. The percentages of replicate trees in which the associated taxa clustered together in the bootstrap test are shown in nodes.</p

    Nucleotide divergence (Pi) in 73 <i>ompF</i> sequences.

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    <p>The regions predicted to correspond to the external loops (L1–L8) are colored green, regions putatively exposed to the periplasm and predicted transmembrane strands (1-16β) are indicated by black shading, the signal sequence (Sig.s.) is colored blue.</p

    Schematic representation of recombination events with brake-points location in the <i>ompF</i> gene of <i>Yersinia</i>.

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    <p>Schematic representation of recombination events with brake-points location in the <i>ompF</i> gene of <i>Yersinia</i>.</p

    The Metabolite Profiling of <i>Aspergillus fumigatus</i> KMM4631 and Its Co-Cultures with Other Marine Fungi

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    An Aspergillus fumigatus KMM 4631 strain was previously isolated from a Pacific soft coral Sinularia sp. sample and was found to be a source of a number of bioactive secondary metabolites. The aims of this work are the confirmation of this strain’ identification based on ITS, BenA, CaM, and RPB2 regions/gene sequences and the investigation of secondary metabolite profiles of Aspergillus fumigatus KMM 4631 culture and its co-cultures with Penicillium hispanicum KMM 4689, Amphichorda sp. KMM 4639, Penicillium sp. KMM 4672, and Asteromyces cruciatus KMM 4696 from the Collection of Marine Microorganisms (PIBOC FEB RAS, Vladivostok, Russia). Moreover, the DPPH-radical scavenging activity, urease inhibition, and cytotoxicity of joint fungal cultures’ extracts on HepG2 cells were tested. The detailed UPLC MS qTOF investigation resulted in the identification and annotation of indolediketopiperazine, quinazoline, and tryptoquivaline-related alkaloids as well as a number of polyketides (totally 20 compounds) in the extract of Aspergillus fumigatus KMM 4631. The metabolite profiles of the co-cultures of A. fumigatus with Penicillium hispanicum, Penicillium sp., and Amphichorda sp. were similar to those of Penicillium hispanicum, Penicillium sp., and Amphichorda sp. monocultures. The metabolite profile of the co-culture of A. fumigatus with Asteromyces cruciatus differed from that of each monoculture and may be more promising for the isolation of new compounds
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