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Labrie, Simon

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Simon

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Université Laval.Département de biochimie et de microbiologie

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Voici les éléments 1 - 10 sur 12
  • PublicationRestreint
    Genomic diversity of phages infecting probiotic strains of Lactobacillus paracasei
    (American Society for Microbiology, 2015-12-22) Mercanti, Diego J.; Tremblay, Denise; Moineau, Sylvain; Capra, María Luján; Labrie, Simon; Luján Quiberoni, Andrea del; Rousseau, Geneviève M.
    Strains of the Lactobacillus casei group have been extensively studied because some are used as probiotics in foods. Conversely, their phages have received much less attention. We analyzed the complete genome sequences of five L. paracasei temperate phages: CL1, CL2, iLp84, iLp1308, and iA2. Only phage iA2 could not replicate in an indicator strain. The genome lengths ranged from 34,155 bp (iA2) to 39,474 bp (CL1). Phages iA2 and iLp1308 (34,176 bp) possess the smallest genomes reported, thus far, for phages of the L. casei group. The GC contents of the five phage genomes ranged from 44.8 to 45.6%. As observed with many other phages, their genomes were organized as follows: genes coding for DNA packaging, morphogenesis, lysis, lysogeny, and replication. Phages CL1, CL2, and iLp1308 are highly related to each other. Phage iLp84 was also related to these three phages, but the similarities were limited to gene products involved in DNA packaging and structural proteins. Genomic fragments of phages CL1, CL2, iLp1308, and iLp84 were found in several genomes of L. casei strains. Prophage iA2 is unrelated to these four phages, but almost all of its genome was found in at least four L. casei strains. Overall, these phages are distinct from previously characterized Lactobacillus phages. Our results highlight the diversity of L. casei phages and indicate frequent DNA exchanges between phages and their hosts.
  • PublicationRestreint
    Involvement of the major capsid protein and two early-expressed phage genes in the activity of the lactococcal abortive infection mechanism abiT
    (American Society for Microbiology, 2012-09-07) Tremblay, Denise; Moisan, Maxim; Moineau, Sylvain; Labrie, Simon; Magadán, Alfonso H.; Campanacci, Valérie; Villion, Manuela; Cambillau, Christian
    The dairy industry uses the mesophilic, Gram-positive, lactic acid bacterium (LAB) Lactococcus lactis to produce an array of fermented milk products. Milk fermentation processes are susceptible to contamination by virulent phages, but a plethora of phage control strategies are available. One of the most efficient is to use LAB strains carrying phage resistance systems such as abortive infection (Abi) mechanisms. Yet, the mode of action of most Abi systems remains poorly documented. Here, we shed further light on the antiviral activity of the lactococcal AbiT system. Twenty-eight AbiT-resistant phage mutants derived from the wild-type AbiT-sensitive lactococcal phages p2, bIL170, and P008 were isolated and characterized. Comparative genomic analyses identified three different genes that were mutated in these virulent AbiT-insensitive phage derivatives: e14 (bIL170 [e14bIL170]), orf41 (P008 [orf41P008]), and orf6 (p2 [orf6p2] and P008 [orf6P008]). The genes e14bIL170 and orf41P008 are part of the early-expressed genomic region, but bioinformatic analyses did not identify their putative function. orf6 is found in the phage morphogenesis module. Antibodies were raised against purified recombinant ORF6, and immunoelectron microscopy revealed that it is the major capsid protein (MCP). Coexpression in L. lactis of ORF6p2 and ORF5p2, a protease, led to the formation of procapsids. To our knowledge, AbiT is the first Abi system involving distinct phage genes.
  • PublicationAccès libre
    Characterization of two polyvalent phages infecting Enterobacteriaceae
    (Nature Publishing Group, 2017-01-16) Hamdi, Sana; Tremblay, Denise; Moineau, Sylvain; Labrie, Simon; Rousseau, Geneviève M.; Kourda, Rim Saïed; Ben Slama, Karim
    Bacteriophages display remarkable genetic diversity and host specificity. In this study, we explore phages infecting bacterial strains of the Enterobacteriaceae family because of their ability to infect related but distinct hosts. We isolated and characterized two novel virulent phages, SH6 and SH7, using a strain of Shigella flexneri as host bacterium. Morphological and genomic analyses revealed that phage SH6 belongs to the T1virus genus of the Siphoviridae family. Conversely, phage SH7 was classified in the T4virus genus of the Myoviridae family. Phage SH6 had a short latent period of 16 min and a burst size of 103 ± 16 PFU/infected cell while the phage SH7 latent period was 23 min with a much lower burst size of 26 ± 5 PFU/infected cell. Moreover, phage SH6 was sensitive to acidic conditions (pH < 5) while phage SH7 was stable from pH 3 to 11 for 1 hour. Of the 35 bacterial strains tested, SH6 infected its S. flexneri host strain and 8 strains of E. coli. Phage SH7 lysed additionally strains of E. coli O157:H7, Salmonella Paratyphi, and Shigella dysenteriae. The broader host ranges of these two phages as well as their microbiological properties suggest that they may be useful for controlling bacterial populations.
  • PublicationAccès libre
    First complete genome sequence of Staphylococcus xylosus, a meat starter culture and a host to propagate Staphylococcus aureus phages
    (American Society for microbiology, 2014-07-10) Dumaresq, Jeannot; Tremblay, Denise; Moineau, Sylvain; Labrie, Simon; Wasserscheid, Jessica; Dewar, Ken; Plante, Pier-Luc; Corbeil, Jacques; El Haddad, Lynn
    Staphylococcus xylosus is a bacterial species used in meat fermentation and a commensal microorganism found on animals. We present the first complete circular genome from this species. The genome is composed of 2,757,557 bp, with a G+C content of 32.9%, and contains 2,514 genes and 79 structural RNAs.
  • PublicationAccès libre
    A virulent phage infecting lactococcus garvieae, with homology to lactococcus lactis phages
    (American Society for Microbiology, 2015-11-13) Eraclio, Giovanni; Tremblay, Denise; Lacelle-Côté, Alexia; Moineau, Sylvain; Labrie, Simon; Fortina, Maria G.
    A new virulent phage belonging to the Siphoviridae family and able to infect Lactococcus garvieae strains was isolated from compost soil. Phage GE1 has a prolate capsid (56 by 38 nm) and a long noncontractile tail (123 nm). It had a burst size of 139 and a latent period of 31 min. Its host range was limited to only two L. garvieae strains out of 73 tested. Phage GE1 has a double-stranded DNA genome of 24,847 bp containing 48 predicted open reading frames (ORFs). Putative functions could be assigned to only 14 ORFs, and significant matches in public databases were found for only 17 ORFs, indicating that GE1 is a novel phage and its genome contains several new viral genes and encodes several new viral proteins. Of these 17 ORFs, 16 were homologous to deduced proteins of virulent phages infecting the dairy bacterium Lactococcus lactis, including previously characterized prolate-headed phages. Comparative genome analysis confirmed the relatedness of L. garvieae phage GE1 to L. lactis phages c2 (22,172 bp) and Q54 (26,537 bp), although its genome organization was closer to that of phage c2. Phage GE1 did not infect any of the 58 L. lactis strains tested. This study suggests that phages infecting different lactococcal species may have a common ancestor.
  • PublicationAccès libre
    A mutation in the methionine aminopeptidase gene provides phage resistance in Streptococcus thermophilus
    (Nature Publishing Group, 2019-09-25) Tremblay, Denise; Mosterd, Cas; Loignon, Stéphanie; Moineau, Sylvain; Dupuis, Marie-Ève; Labrie, Simon; Rousseau, Geneviève M.; Romero, Dennis A.; Desjardins, Philippe; Horvath, Philippe; Fremaux, Christophe
    Streptococcus thermophilus is a lactic acid bacterium widely used by the dairy industry for the manufacture of yogurt and specialty cheeses. It is also a Gram-positive bacterial model to study phagehost interactions. CRISPR-Cas systems are one of the most prevalent phage resistance mechanisms in S. thermophilus. Little information is available about other host factors involved in phage replication in this food-grade streptococcal species. We used the model strain S. thermophilus SMQ-301 and its virulent phage DT1, harboring the anti-CRISPR protein AcrIIA6, to show that a host gene coding for a methionine aminopeptidase (metAP) is necessary for phage DT1 to complete its lytic cycle. A single mutation in metAP provides S. thermophilus SMQ-301 with strong resistance against phage DT1. The mutation impedes a late step of the lytic cycle since phage adsorption, DNA replication, and protein expression were not afected. When the mutated strain was complemented with the wild-type version of the gene, the phage sensitivity phenotype was restored. When this mutation was introduced into other S. thermophilus strains it provided resistance against cos-type (Sf21dt1virus genus) phages but replication of pac-type (Sf11 virus genus) phages was not afected. The mutation in the gene coding for the MetAP induces amino acid change in a catalytic domain conserved across many bacterial species. Introducing the same mutation in Streptococcus mutans also provided a phage resistance phenotype, suggesting the wide-ranging importance of the host methionine aminopeptidase in phage replication.
  • PublicationRestreint
    A new Microviridae phage isolated from a failed biotechnological process driven by Escherichia coli
    (American Society for Microbiology, 2014-10-17) Tremblay, Denise; Moineau, Sylvain; Dupuis, Marie-Ève; Labrie, Simon; Plante, Pier-Luc; Corbeil, Jacques
    Bacteriophages are present in every environment that supports bacterial growth, including manmade ecological niches. Virulent phages may even slow or, in more severe cases, interrupt bioprocesses driven by bacteria. Escherichia coli is one of the most widely used bacteria for large-scale bioprocesses; however, literature describing phage-host interactions in this industrial context is sparse. Here, we describe phage MED1 isolated from a failed industrial process. Phage MED1 (Microviridae family, with a single-stranded DNA [ssDNA] genome) is highly similar to the archetypal phage phiX174, sharing >95% identity between their genomic sequences. Whole-genome phylogenetic analysis of 52 microvirus genomes from public databases revealed three genotypes (alpha3, G4, and phiX174). Phage MED1 belongs to the phiX174 group. We analyzed the distribution of single nucleotide variants in MED1 and 18 other phiX174-like genomes and found that there are more missense mutations in genes G, B, and E than in the other genes of these genomes. Gene G encodes the spike protein, involved in host attachment. The evolution of this protein likely results from the selective pressure on phages to rapidly adapt to the molecular diversity found at the surface of their hosts.
  • PublicationAccès libre
    Characterization of the escherichia coli virulent myophage ST32
    (MDPI, 2018-11-07) Tremblay, Denise; Moineau, Sylvain; Geagea, Hany; Labrie, Simon; Liu, Honghui; Liu, Xinchun; Rousseau, Geneviève M.
    The virulent phage ST32 that infects the Escherichia coli strain ST130 was isolated from a wastewater sample in China and analyzed. Morphological observations showed that phage ST32 belongs to the Myoviridae family, as it has an icosahedral capsid and long contractile tail. Host range analysis showed that it exhibits a broad range of hosts including non-pathogenic and pathogenic E. coli strains. Interestingly, phage ST32 had a much larger burst size when amplified at 20 °C as compared to 30 °C or 37 °C. Its double-stranded DNA genome was sequenced and found to contain 53,092 bp with a GC content of 44.14%. Seventy-nine open reading frames (ORFs) were identified and annotated as well as a tRNA-Arg. Only nineteen ORFs were assigned putative functions. A phylogenetic tree using the large terminase subunit revealed a close relatedness with four unclassified Myoviridae phages. A comparative genomic analysis of these phages showed that the Enterobacteria phage phiEcoM-GJ1 is the closest relative to ST32 and shares the same new branch in the phylogenetic tree. Still, these two phages share only 47 of 79 ORFs with more than 90% identity. Phage ST32 has unique characteristics that make it a potential biological control agent under specific conditions.
  • PublicationAccès libre
    Complete genome sequence of Streptococcus thermophilus SMQ-301, a model strain for phage-host interactions
    (American Society for Microbiology, 2015-05-21) Tremblay, Denise; Moineau, Sylvain; Labrie, Simon; Wasserscheid, Jessica; Dewar, Ken; Plante, Pier-Luc; Corbeil, Jacques
    Streptococcus thermophilus is used by the dairy industry to manufacture yogurt and several cheeses. Using PacBio and Illumina platforms, we sequenced the genome of S. thermophilus SMQ-301, the host of several virulent phages. The genome is composed of 1,861,792 bp and contains 2,037 genes, 67 tRNAs, and 18 rRNAs.
  • PublicationAccès libre
    Characterization of five podoviridae phages infecting Citrobacter freundii
    (Frontiers Research Foundation, 2016-06-29) Hamdi, Sana; Tremblay, Denise; Moineau, Sylvain; Labrie, Simon; Kourda, Rim Saïed; Rousseau, Geneviève M.; Ben Slama, Karim
    Citrobacter freundii causes opportunistic infections in humans and animals, which are becoming difficult to treat due to increased antibiotic resistance. The aim of this study was to explore phages as potential antimicrobial agents against this opportunistic pathogen. We isolated and characterized five new virulent phages, SH1, SH2, SH3, SH4, and SH5 from sewage samples in Tunisia. Morphological and genomic analyses revealed that the five C. freundii phages belong to the Caudovirales order, Podoviridae family, and Autographivirinae subfamily. Their linear double-stranded DNA genomes range from 39,158 to 39,832 bp and are terminally redundant with direct repeats between 183 and 242 bp. The five genomes share the same organization as coliphage T7. Based on genomic comparisons and on the phylogeny of the DNA polymerases, we assigned the five phages to the T7virus genus but separated them into two different groups. Phages SH1 and SH2 are very similar to previously characterized phages phiYeO3-12 and phiSG-JL2, infecting, respectively, Yersinia enterocolitica and Salmonella enterica, as well as sharing more than 80% identity with most genes of coliphage T7. Phages SH3, SH4, and SH5 are very similar to phages K1F and Dev2, infecting, respectively, Escherichia coli and Cronobacter turicensis. Several structural proteins of phages SH1, SH3, and SH4 were detected by mass spectrometry. The five phages were also stable from pH 5 to 10. No genes coding for known virulence factors or integrases were found, suggesting that the five isolated phages could be good candidates for therapeutic applications to prevent or treat C. freundii infections. In addition, this study increases our knowledge about the evolutionary relationships within the T7virus genus.