Personne :
Rousseau, Geneviève M.

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Rousseau
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Geneviève M.
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Département de biochimie, de microbiologie et de bio-informatique, Faculté des sciences et de génie, Université Laval
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https://orcid.org/0000-0002-1792-626X
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ncf12004028
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2006 - 200952010 - 201918
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Voici les éléments 1 - 10 sur 23
  • Publication
    Restreint
    Lactococcus lactis type III-A CRISPR-Cas system cleaves bacteriophage RNA
    (Tandfonline, 2018-10-02) Millen, Anne M.; Tremblay, Denise; Moineau, Sylvain; Samson, Julie; Magadán, Alfonso H.; Rousseau, Geneviève M.; Romero, Dennis A.
    CRISPR-Cas defends microbial cells against invading nucleic acids including viral genomes. Recent studies have shown that type III-A CRISPR-Cas systems target both RNA and DNA in a transcriptiondependent manner. We previously found a type III-A system on a conjugative plasmid in Lactococcus lactis which provided resistance against virulent phages of the Siphoviridae family. Its naturally occurring spacers are oriented to generate crRNAs complementary to target phage mRNA, suggesting transcription-dependent targeting. Here, we show that only constructs whose spacers produce crRNAs complementary to the phage mRNA confer phage resistance in L. lactis. In vivo nucleic acid cleavage assays showed that cleavage of phage dsDNA genome was not detected within phage-infected L. lactis cells. On the other hand, Northern blots indicated that the lactococcal CRISPR-Cas cleaves phage mRNA in vivo. These results cannot exclude that single-stranded phage DNA is not being targeted, but phage DNA replication has been shown to be impaired.
  • Publication
    Restreint
    Peptidoglycan hydrolase fusions maintain their parental specificities
    (American Society for Microbiology, 2006-04-01) Donovan, David M.; Moineau, Sylvain; Dong, Shengli; Rousseau, Geneviève M.; Garrett, Wes; Pritchard, David G.
    The increased incidence of bacterial antibiotic resistance has led to a renewed search for novel antimicrobials. Avoiding the use of broad-range antimicrobials through the use of specific peptidoglycan hydrolases (endolysins) might reduce the incidence of antibiotic-resistant pathogens worldwide. Staphylococcus aureus and Streptococcus agalactiaeare human pathogens and also cause mastitis in dairy cattle. The ultimate goal of this work is to create transgenic cattle that are resistant to mastitis through the expression of an antimicrobialprotein(s) in their milk. Toward this end, two novel antimicrobials were produced. The (i) full-length and (ii)182-amino-acid, C-terminally truncatedS. agalactiae bacteriophage B30 endolysins were fused to the mature lysostaphin protein of Staphylococcus simulans. Both fusions display lytic specificity for streptococcal pathogensandS. aureus. The full lytic ability of the truncated B30 protein also suggests that the SH3b domain at the Cterminus is dispensable. The fusions are active in a milk-like environment. They are also active against some lactic acid bacteria used to make cheese and yogurt, but their lytic activity is destroyed by pasteurization (63°Cfor 30 min). Immunohistochemical studies indicated that the fusion proteins can be expressed in cultured mammalian cells with no obvious deleterious effects on the cells, making it a strong candidate for use in future transgenic mice and cattle. Since the fusion peptidoglycan hydrolase also kills multiple human pathogens, it also may prove useful as a highly selective, multipathogen-targeting antimicrobial agent that could potentially reduce the use of broad-range antibiotics in fighting clinical infections.
  • Publication
    Restreint
    Comparison of polycarbonate and polytetrafluoroethylene filters for sampling of airborne bacteriophages
    (Elsevier, 2010-01-22) Duchaine, Caroline; Gendron, Louis; Moineau, Sylvain; Massé, Daniel; Verreault, Daniel; Rousseau, Geneviève M.
    Aerosolized coliphage phiX174 and lactococcal phage P008 were sampled with two types of filter, polycarbonate (PC) and polytetrafluoroethylene (PTFE). The recovery was determined by plaque assays and quantitative polymerase chain reaction (qPCR). Recovery by qPCR was greater than by culture and PC filters outperformed PTFE filters both by culture and by qPCR relative recovery. The results of the plaque assays showed that the infectivity of the recovered phages was affected by the aerosolization/air sampling. The presence of viruses in air samples should be determined by culture-independent assays.
  • Publication
    Accès libre
    Étude de l'évolution des phages de l'espèce 936 de Lactococcus lactis
    (2007) Rousseau, Geneviève M.; Moineau, Sylvain
    Lactococcus lactis transforme le lait en produits fermentes, mais parfois des bactériophages virulents peuvent altérer ce processus. Les phages de l'espèce 936 de L. lactis sont principalement retrouvés dans l'industrie de la transformation du lait. Une meilleure compréhension de leurs mécanismes évolutifs pourrait permettre un meilleur contrôle de cette espèce de phages. Dans ce travail, l'analyse de six phages de l'espèce 936 infectant la même souche industrielle de L. lactis et isolés dans la même fromagerie québécoise a été effectuée. Le séquençage complet de leur génome à ADN, une identification des protéines structurales ainsi que des hybridations de type ADN-ADN ont été réalisées. Après analyses comparatives, deux phages se sont révélés à 100% identiques et ce, même s'ils ont été isolés à 14 mois d'intervalle. De plus, aucun ADN des phages à l'étude n'a été retrouvé dans le génome des bactéries hôtes. Ces résultats suggèrent que ces phages sont capables de persister dans une usine et de s'échanger du matériel génétique entre eux.
  • Publication
    Accès libre
    Le système CRISPR-Cas : au-delà de l’édition génomique
    (2018-11-19) Moineau, Sylvain; Croteau, Félix R.; Rousseau, Geneviève M.
    CRISPR-Cas est un système immunitaire adaptatif utilisé par de nombreux microbes pour se défendre contre l’invasion d’acides nucléiques tels que les génomes viraux et autres éléments génétiques mobiles. Le système microbien utilise son locus CRISPR pour stocker de l’information génétique afin de produire des ARN guides. Ces derniers, de concert avec des endonucléases (Cas), empêchent des invasions futures. Des parties de ce système microbien ont été exploitées pour développer un puissant outil d’édition des génomes dans une panoplie d’organismes. La capacité de CRISPR-Cas9 à couper efficacement et à des endroits très précis de l’ADN pourrait peut-être permettre un jour de guérir certaines maladies génétiques humaines. La malléabilité de cet outil d’édition rend possible une variété d’applications allant de la modulation de l’expression de gènes à des modifications épigénétiques. Les locus CRISPR représentent également une mine d’informations pouvant servir de méthode de typage de souches microbiennes ou encore une façon d’étudier les interactions entre les bactéries et leurs habitats.
  • Publication
    Accès libre
    Identification and characterization of the phage gene sav, involved in sensitivity to the lactococcal abortive infection mechanism AbiV
    (American Society for Microbiology, 2009-04-06) Haaber, Jakob; Moineau, Sylvain; Rousseau, Geneviève M.; Hammer, Karin
    Lactococcus lactis phage mutants that are insensitive to the recently characterized abortive infection mechanism AbiV were isolated and analyzed in an effort to elucidate factors involved in the sensitivity to AbiV. Whole-genome sequencing of the phage mutants p2.1 and p2.2 revealed mutations in an orf that is transcribed early, indicating that this orf was responsible for AbiV sensitivity. Sequencing of the homologous regions in the genomes of other AbiV-insensitive mutants derived from p2 and six other lactococcal wild-type phages revealed point mutations in the homologous orf sequences. The orf was named sav (for sensitivity to AbiV), and the encoded polypeptide was named SaV. The purification of a His-tagged SaV polypeptide by gel filtration suggested that the polypeptide formed a dimer in its native form. The overexpression of SaV in L. lactis and Escherichia coli led to a rapid toxic effect. Conserved, evolutionarily related regions in SaV polypeptides of different phage groups are likely to be responsible for the AbiV-sensitive phenotype and the toxicity.
  • Publication
    Accès libre
    Complete genome sequence of Escherichia coli Siphophage BRET
    (American Society for Microbiology, 2019-01-31) Ngazoa-Kakou, Solange; Tremblay, Denise; Moineau, Sylvain; Plante, Pier-Luc; Addablah, Audrey A.; Lemire, Nicolas; Corbeil, Jacques; Hutinet, Geoffrey; Rousseau, Geneviève M.; Shao, Yuyu; Koudou, Aristide; Soro, Benjamin K.; Coulibaly, David N.; Aoussi, Serge; Dosso, Mireille
    The lytic Escherichia coli siphophage BRET was isolated from a chicken obtained at a local market in Abidjan, Côte d’Ivoire. Its linear genome sequence consists of 59,550 bp (43.4% GC content) and contains 88 predicted genes, including 4 involved in archaeosine biosynthesis. Phage BRET is related (95% nucleotide identity) to Enterobacteria phage JenK1
  • Publication
    Restreint
    The cell lysis activity of the Streptococcus agalactiae bacteriophage B30 endolysin relies on the cysteine, histidine-dependent amidohydrolase/peptidase domain
    (American Society for Microbiology, 2006-07-01) Donovan, David M.; Moineau, Sylvain; Foster-Frey, Juli; Rousseau, Geneviève M.; Dong, Shengli; Pritchard, David G.
    The Streptococcus agalactiae bacteriophage B30 endolysin contains three domains : cysteine, histidine-dependent amidohydrolase/peptidase (CHAP), Acm glycosidase, and the SH3b cell wall binding domain. Truncations and point mutations indicated that the Acm domain requires the SH3b domain for activity, while the CHAP domain is responsible for nearly all the cell lysis activity.
  • Publication
    Restreint
    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.
  • Publication
    Restreint
    Comparison of polycarbonate and polytetrafluoroethylene filters for sampling of airborne bacteriophages
    (Elsevier, 2010-01-22) Duchaine, Caroline; Moineau, Sylvain; Massé, Daniel; Verreault, Daniel; Rousseau, Geneviève M.; Gendron, Louis
    Aerosolized coliphage phiX174 and lactococcal phage P008 were sampled with two types of filter, polycarbonate (PC) and polytetrafluoroethylene (PTFE). The recovery was determined by plaque assays and quantitative polymerase chain reaction (qPCR). Recovery by qPCR was greater than by culture and PC filters outperformed PTFE filters both by culture and by qPCR relative recovery. The results of the plaque assays showed that the infectivity of the recovered phages was affected by the aerosolization/air sampling. The presence of viruses in air samples should be determined by culture-independent assays.