Dissertação(mestrado) - Universidade Federal do Rio Grande, Programa de Pós-Graduação em Engenharia e Ciência de Alimentos, Escola de Química e Alimentos, 2007. / Submitted by Caroline Silva (krol_bilhar@hotmail.com) on 2012-10-22T16:47:04Z No. of bitstreams: 1 anlise de perigos e pontos crticos de controle.pdf: 1012043 bytes, checksum: a178ea7de80daa5097795f55e1f95573 (MD5) / Approved for entry into archive by Bruna Vieira(bruninha_vieira@ibest.com.br) on 2012-11-06T15:05:02Z (GMT) No. of bitstreams: 1 anlise de perigos e pontos crticos de controle.pdf: 1012043 bytes, checksum: a178ea7de80daa5097795f55e1f95573 (MD5) / Made available in DSpace on 2012-11-06T15:05:02Z (GMT). No. of bitstreams: 1 anlise de perigos e pontos crticos de controle.pdf: 1012043 bytes, checksum: a178ea7de80daa5097795f55e1f95573 (MD5) Previous issue date: 2007 / O programa de qualidade Análise de Perigos e Pontos Críticos de Controle – APPCC, segundo a NBR/ANVISA no 14.900, estabelece como princípios, a prevenção de riscos à saúde humana, bem como a redução ou eliminação de alterações nos alimentos através da aplicação de práticas de controles operacionais ao longo da cadeia produtiva. Desta maneira, a aplicação deste programa é considerada uma importante ferramenta para a segurança alimentar e controle de qualidade dos alimentos destinados ao consumo humano. São pré-requisitos fundamentais, as Boas Práticas de Fabricação - BPF, constituindo-se na base higiênico-sanitária para implantação do sistema. A implantação destas práticas simplifica e viabiliza o plano, assegurando sua integridade e eficiência operacional. Como partes da metodologia de avaliação do programa, foram identificadas as fases operacionais relacionadas ao processamento e estabelecido um sistema de vigilância para cada Pontos Críticos de Controle-PCC. Foram determinados os limites críticos e suas medidas preventivas e corretivas. Em função dos perigos de natureza biológica, associados à saúde pública deve ser avaliada a presença de microrganismos relacionados com a segurança alimentar, deterioradores e/ou patogênicos: Salmonella sp., coliformes a 45 oC, Staphylococcus coagulase positiva e Pseudomonas sp. As Pseudomonas sp. são as bactérias de maior incidência neste tipo de matéria-prima e indicadoras da extensão da deterioração. A decomposição por este microrganismo produz sabores e odores sulfidrílicos. O odor de frutas podres é produzido pela Pseudomonas fragi através da decomposição de aminoácidos monoamínicos ou monocarboxílicos com formação de aldeídos, sulfitos voláteis, cetonas e ésteres. Foi realizado o monitoramento deste microrganismo, através de uma avaliação microbiológica durante o recebimento, no pescado in natura, nos filés processados e pré-embalados e no produto final, congelado. O trabalho objetiva a avaliação dos PCC no processamento do filé congelado de tilápia (Oreochromis niloticus) na modalidade Individual Quick Frozen – IQF, produzido pela Costa Sul Pescados Ltda. /SC. / The quality program Analysis of Dangers and Critical Points of Control - HACCP, according to NBR/ANVISA no.14.900, establishes as principles, the prevention of risks to the human health, as well as the reduction or elimination of alterations to food via the application of practices of operational controls along the productive chain. Thus, the application of this program is considered an important tool for the alimentary safety and control of quality of food destined to human consumption. They are fundamental requirements, the Good Practices of Production – GPP, making up the hygienic-sanitary base for implantation of the system. The implantation of these practices simplifies and it makes possible the plan, assuring its integrity and operational efficiency. As part of the methodology of evaluation of the program, it was identified the operational phases related to processing and established a surveillance system for each CPC. The critical limits were established and its preventive and corrective measures. Concerning to the dangers of biological nature, associated to the public health the presence of microorganisms related with the alimentary safety, deteriorating and/or pathogenic agents should be evaluated: Salmonella sp., coliforms to 45 oC, Staphylococcus positive coagulase and Pseudomonas sp. The Pseudomonas sp. are bacteria of large incidence in this type of raw material and indicative of the extension of deterioration. The decomposition for Pseudomonas sp. produces sulfidrilic flavors and scents. The scent of rotten fruits is produced by the Pseudomonas fragi through the decomposition of monoamine or monocarboxyl aminoacids with formation of aldehydes, volatile sulfites, acetones and esters. It was intended, through an microbiological evaluation, to monitor this microorganism, during the process of receiving fish in natura, in the filets processed and pre-packed and final product under storage. The work aims at the evaluation of the Critical Points of Control in the processing of the frozen filet of tilapia (Oreochromis niloticus) in the Individual modality Quick Frozen - IQF, produced by Costa Sul Pescados Ltd. /SC.

Em consultórios odontológicos são utilizadas canetas rotatórias que durante seu uso entram em contato com a microbiota oral, podendo trazer conseqüências para o próprio paciente ou para outros que utilizarem o mesmo equipamento, se não houver um tratamento apropriado para sua reutilização. Para avaliar a eficiência de diferentes tratamentos utilizados rotineiramente na limpeza e desinfecção de equipamentos odontológicos, este trabalho descreve a produção de biofime in vitro em superfície de canetas odontológicas e a eficiência dos biocidas glutaraldeído, ácido peracético e álcool 70%, do detergente enzimático e da lavagem ultra-sônica para remoção do biofilme induzido, utilizando amostras de Pseudomonas aeruginosa e Staphylococcus aureus. Para a padronização dos métodos, além de curvas de crescimento de ambos os micro-organismos, foram realizados testes de adesão em cupons obtidos pelo corte das canetas. Foram testados diferentes tempos de incubação para a produção do biofilme, cujo valor máximo foi obtido em 14 dias. A avaliação da formação de biofilme foi realizada pelo método de contagem de bactérias viáveis (CBV), por microscopia eletrônica de varredura (MEV) e pelo método Cristal Violeta. A eficiência dos tratamentos na remoção do biofilme foi determinada pela diferença entre o número de células aderidas aos cupons submetidos ao tratamento e os cupons não submetidos. Maior remoção foi observada nos cupons tratados com ácido peracético, glutaraldeído e álcool 70% comparados aqueles tratados com detergente enzimático, lavagem ultra-sônica e solução salina. Os três primeiros tiveram eficiências similares, demonstradas pelos métodos CBV e MEV. O efeito dos tratamentos em S.aureus foi semelhante ao observado em P. aeruginosa, exceto a lavagem ultra-sônica que em S.aureus demonstrou melhor desempenho. Os tratamentos utilizados neste trabalho reduziram o biofilme em cupons de canetas odontológicas, mas não o removeram completamente, comprometendo a biossegurança na reutilização das canetas. / Rotating pens during its use in dental offices come into contact with the oral microbiota and may bring consequences to the patient or to others who use the same equipment, if there is not a clean suitable for reuse. To evaluate the efficiency of different treatments utilized routinely for cleaning dental equipments, this study describes the in vitro biofilm production on surfaces of dental pens and the efficiency of the biocides glutaraldehyde, peracetic acid, alcohol 70%, detergent enzyme and ultrasound rinsing for biofilm removal, using Pseudomonas aeruginosa and Staphylococcus aureus strains. For the standardization of methods, and growth curves of both microorganisms, adhesion tests were performed on coupons obtained by cutting the pens. We tested different incubation times for the production of biofilm, whose maximum value was obtained in 14 days. Evaluation of biofilm formation was performed by the method of counting viable bacteria (CBV) and scanning electron microscopy (SEM) and Crystal Violet method.The efficiency of treatments on biofilm removal was determined by the difference between the number of cells attached to coupons submitted and not submitted to treatment. Higher removal was observed on the coupons treated with peracetic acid, glutaraldehyde and 70% alcohol than in those treated with enzyme detergent, ultrasonic washing and saline. The first three had similar efficiencies, as demonstrated by CBV and SEM. The effect of treatment on S. aureus was similar to that observed in P. aeruginosa, except for ultrasonic washing in S. aureus that showed better performance. Therefore, the treatments used in this work reduced but not completely removed the biofilm in dental coupons pens, which can compromise the biological safety when they are reused.

Em consultórios odontológicos são utilizadas canetas rotatórias que durante seu uso entram em contato com a microbiota oral, podendo trazer conseqüências para o próprio paciente ou para outros que utilizarem o mesmo equipamento, se não houver um tratamento apropriado para sua reutilização. Para avaliar a eficiência de diferentes tratamentos utilizados rotineiramente na limpeza e desinfecção de equipamentos odontológicos, este trabalho descreve a produção de biofime in vitro em superfície de canetas odontológicas e a eficiência dos biocidas glutaraldeído, ácido peracético e álcool 70%, do detergente enzimático e da lavagem ultra-sônica para remoção do biofilme induzido, utilizando amostras de Pseudomonas aeruginosa e Staphylococcus aureus. Para a padronização dos métodos, além de curvas de crescimento de ambos os micro-organismos, foram realizados testes de adesão em cupons obtidos pelo corte das canetas. Foram testados diferentes tempos de incubação para a produção do biofilme, cujo valor máximo foi obtido em 14 dias. A avaliação da formação de biofilme foi realizada pelo método de contagem de bactérias viáveis (CBV), por microscopia eletrônica de varredura (MEV) e pelo método Cristal Violeta. A eficiência dos tratamentos na remoção do biofilme foi determinada pela diferença entre o número de células aderidas aos cupons submetidos ao tratamento e os cupons não submetidos. Maior remoção foi observada nos cupons tratados com ácido peracético, glutaraldeído e álcool 70% comparados aqueles tratados com detergente enzimático, lavagem ultra-sônica e solução salina. Os três primeiros tiveram eficiências similares, demonstradas pelos métodos CBV e MEV. O efeito dos tratamentos em S.aureus foi semelhante ao observado em P. aeruginosa, exceto a lavagem ultra-sônica que em S.aureus demonstrou melhor desempenho. Os tratamentos utilizados neste trabalho reduziram o biofilme em cupons de canetas odontológicas, mas não o removeram completamente, comprometendo a biossegurança na reutilização das canetas. / Rotating pens during its use in dental offices come into contact with the oral microbiota and may bring consequences to the patient or to others who use the same equipment, if there is not a clean suitable for reuse. To evaluate the efficiency of different treatments utilized routinely for cleaning dental equipments, this study describes the in vitro biofilm production on surfaces of dental pens and the efficiency of the biocides glutaraldehyde, peracetic acid, alcohol 70%, detergent enzyme and ultrasound rinsing for biofilm removal, using Pseudomonas aeruginosa and Staphylococcus aureus strains. For the standardization of methods, and growth curves of both microorganisms, adhesion tests were performed on coupons obtained by cutting the pens. We tested different incubation times for the production of biofilm, whose maximum value was obtained in 14 days. Evaluation of biofilm formation was performed by the method of counting viable bacteria (CBV) and scanning electron microscopy (SEM) and Crystal Violet method.The efficiency of treatments on biofilm removal was determined by the difference between the number of cells attached to coupons submitted and not submitted to treatment. Higher removal was observed on the coupons treated with peracetic acid, glutaraldehyde and 70% alcohol than in those treated with enzyme detergent, ultrasonic washing and saline. The first three had similar efficiencies, as demonstrated by CBV and SEM. The effect of treatment on S. aureus was similar to that observed in P. aeruginosa, except for ultrasonic washing in S. aureus that showed better performance. Therefore, the treatments used in this work reduced but not completely removed the biofilm in dental coupons pens, which can compromise the biological safety when they are reused.

Made available in DSpace on 2016-06-02T19:31:43Z (GMT). No. of bitstreams: 1 2506.pdf: 900946 bytes, checksum: 97bcd58db188bc414e74218995bbe7c1 (MD5) Previous issue date: 2009-05-27 / Financiadora de Estudos e Projetos / A hundred sixty samples of water were collected to assess the sanitary and ecoepidemiological conditions of collective swimming pools in São Carlos SP. The samples were collected between August/2007 and Abril/2008. The pools were characterized by application of a questionnaire, answered by people responsable for the water treatment. Physical and chemical analysis included: pH, temperature, alkalinity, free chlorine concentration and turbidity. All water samples were analyzed for heterotrophic plate counts by pour plate method. Membrane filter technique was used to isolate amoebae and other bacteria. Eleven pools were heated and nine were unheated. Half of the pools was indoors and the other half was outdoors. Seventeen pools were chlorinated and three pools had a combined disinfection, two using chlorine and UV and one using chlorine and ozone. Only 13 samples (8%) conformed within the desired standards for pH, turbidity and free chlorine concentration at the same time. Twelve samples (7.5 %) were unacceptable for heterotrophic bacteria and 63 (39 %) were unsatisfactory for the presence of total coliforms. Escherichia coli was detected in two samples. Moreover, 102 samples (64 %) were contaminated with at least one microorganism.The percentages of occurrence were: 14 % for Staphylococcus spp, 35 % for Pseudomonas spp, 33 % for Mycobacterium spp and 21 % for free-living amoebae. The amoebae identified were used to recover bacteria possibly present intracellularly . Of these 33 samples positive for protozoa, 18 (54 %) harbored Mycobacterium spp, 15 (45 %) harbored Pseudomonas spp and one (3 %) harbored Staphylococcus spp. Escherichia coli was not recovered from amoebae. The physical and chemical parameters most related to the occurrence of microorganisms in the samples studied were pH and chlorine. No significant relationship was identified between water temperature and occurrence of microorganisms. Overall, the inappropriate forms of treatment and maintenance of swimming pools studied might create conditions for the development of microorganisms, including those potentially pathogenic for human. / Com o intuito de avaliar as condições ecoepidemiológicas e sanitárias de piscinas coletivas da cidade de São Carlos SP, foram coletadas 160 amostras de água em 20 piscinas, entre Agosto/2007 e Abril/2008. As piscinas foram caracterizadas através de aplicação de questionário junto aos responsáveis pelo tratamento da água. Os parâmetros físico-químicos analisados foram: pH, temperatura, alcalinidade, concentração de cloro livre e turbidez. A análise microbiológica foi realizada através de contagem de bactérias heterotróficas (método de pour plate ) e de concentração em membrana filtrante para a pesquisa de coliformes totais, Escherichia coli, Staphylococcus spp, Pseudomonas spp, Mycobacterium spp e amebas de vida livre. Entre as piscinas analisadas, 11 eram aquecidas e nove não-aquecidas. Metade das piscinas localizava-se em ambiente interno e a outra metade em ambiente externo. Dezessete piscinas eram cloradas e três delas faziam tratamento de desinfecção combinado: duas utilizando cloro e UV e uma utilizando cloro e ozônio. Apenas 13 amostras (8 %) se apresentaram dentro dos padrões desejados para pH, turbidez e concentração de cloro livre ao mesmo tempo. Doze amostras (7,5 %) estavam fora do padrão sugerido para bactérias heterotróficas e 63 (39 %) foram consideradas insatisfatórias quanto à presença de coliformes totais. Escherichia coli foi detectada em duas amostras apenas. Em relação aos outros microrganismos pesquisados, 102 amostras (64 %) apresentaram-se com pelo menos um deles. As porcentagens de ocorrência foram: 14 % para Staphylococcus spp, 35 % para Pseudomonas spp, 33 % para Mycobacterium spp e 21 % para amebas de vida livre. As amebas detectadas foram utilizadas para recuperar bactérias possivelmente presentes em seu interior. Das 33 amostras positivas para esses protozoários, 18 (54 %) demonstraram hospedar Mycobacterium spp, 15 (45 %) abrigavam Pseudomonas spp e uma (3 %) apresentava Staphylococcus spp internalizados. Escherichia coli não foi recuperada a partir de células amebianas. Os parâmetros físico-químicos mais relacionados com a ocorrência de microrganismos nas amostras estudadas foram o pH e o cloro. Não foi identificada relação significativa entre a temperatura da água e a ocorrência de microrganismos. De forma geral, foi possível observar certo descuido quanto às formas adequadas de tratamento e manutenção das águas das piscinas estudadas, o que pode colocar em risco a saúde dos freqüentadores, ao criar condições para o desenvolvimento de microrganismos, inclusive para aqueles potencialmente patogênicos.

Em consultórios odontológicos são utilizadas canetas rotatórias que durante seu uso entram em contato com a microbiota oral, podendo trazer conseqüências para o próprio paciente ou para outros que utilizarem o mesmo equipamento, se não houver um tratamento apropriado para sua reutilização. Para avaliar a eficiência de diferentes tratamentos utilizados rotineiramente na limpeza e desinfecção de equipamentos odontológicos, este trabalho descreve a produção de biofime in vitro em superfície de canetas odontológicas e a eficiência dos biocidas glutaraldeído, ácido peracético e álcool 70%, do detergente enzimático e da lavagem ultra-sônica para remoção do biofilme induzido, utilizando amostras de Pseudomonas aeruginosa e Staphylococcus aureus. Para a padronização dos métodos, além de curvas de crescimento de ambos os micro-organismos, foram realizados testes de adesão em cupons obtidos pelo corte das canetas. Foram testados diferentes tempos de incubação para a produção do biofilme, cujo valor máximo foi obtido em 14 dias. A avaliação da formação de biofilme foi realizada pelo método de contagem de bactérias viáveis (CBV), por microscopia eletrônica de varredura (MEV) e pelo método Cristal Violeta. A eficiência dos tratamentos na remoção do biofilme foi determinada pela diferença entre o número de células aderidas aos cupons submetidos ao tratamento e os cupons não submetidos. Maior remoção foi observada nos cupons tratados com ácido peracético, glutaraldeído e álcool 70% comparados aqueles tratados com detergente enzimático, lavagem ultra-sônica e solução salina. Os três primeiros tiveram eficiências similares, demonstradas pelos métodos CBV e MEV. O efeito dos tratamentos em S.aureus foi semelhante ao observado em P. aeruginosa, exceto a lavagem ultra-sônica que em S.aureus demonstrou melhor desempenho. Os tratamentos utilizados neste trabalho reduziram o biofilme em cupons de canetas odontológicas, mas não o removeram completamente, comprometendo a biossegurança na reutilização das canetas. / Rotating pens during its use in dental offices come into contact with the oral microbiota and may bring consequences to the patient or to others who use the same equipment, if there is not a clean suitable for reuse. To evaluate the efficiency of different treatments utilized routinely for cleaning dental equipments, this study describes the in vitro biofilm production on surfaces of dental pens and the efficiency of the biocides glutaraldehyde, peracetic acid, alcohol 70%, detergent enzyme and ultrasound rinsing for biofilm removal, using Pseudomonas aeruginosa and Staphylococcus aureus strains. For the standardization of methods, and growth curves of both microorganisms, adhesion tests were performed on coupons obtained by cutting the pens. We tested different incubation times for the production of biofilm, whose maximum value was obtained in 14 days. Evaluation of biofilm formation was performed by the method of counting viable bacteria (CBV) and scanning electron microscopy (SEM) and Crystal Violet method.The efficiency of treatments on biofilm removal was determined by the difference between the number of cells attached to coupons submitted and not submitted to treatment. Higher removal was observed on the coupons treated with peracetic acid, glutaraldehyde and 70% alcohol than in those treated with enzyme detergent, ultrasonic washing and saline. The first three had similar efficiencies, as demonstrated by CBV and SEM. The effect of treatment on S. aureus was similar to that observed in P. aeruginosa, except for ultrasonic washing in S. aureus that showed better performance. Therefore, the treatments used in this work reduced but not completely removed the biofilm in dental coupons pens, which can compromise the biological safety when they are reused.

<p>Microorganisms, including two fungi, <i>Phytophthora cryptogea</i> and <i>Fusarium oxysporum</i> strain Fo-(IMI 386351), and one bacterium, <i>Pesudomonas</i> sp. strain MF30, were tested for their abilities to stimulate plant defence responses in tomato (<i>Lycopersicon esculentum</i> –L.) and to serve as effective biocontrol agents (<b>Bs</b>). The study included <i>in vivo</i> and <i>in vitro</i> characterization of biological attributes of the microorganisms, pertaining to their abilities to stimulate plant immunity against a fungal pathogen, <i>Fusarium oxysporum</i> f. sp. <i>lycopersici</i> (Fol), the causal agent of tomato wilt disease. Using <i>Lycopersicon esculentum</i> –L. as a model plant for examining some fundamental elements of the plant-microorganism interaction, the study reveals and clarifies some aspects of the close association and the complexity of such systems.</p><p>For each <b>B</b>, the results revealed a <b>B</b>-distinct plant-microorganism interaction, which included systemic induced resistance (SIR). A phylogenetic analyses of the partial sequences of two Fo-(IMI 386351) genes, a mitochondrial small subunit ribosomal DNA (mtSSU rDNA) and the nuclear translation elongation factor 1α (EF-1α), provided phylogenetic trees confirming that Fo-(IMI 386351) might be a member of Fol or of <i>F. oxysporum</i> f. sp. <i>melonis</i>, which have polyphyletic evolutionary origins. RFLP analysis (mtDNA), suggested that Fo-(IMI 386351) probably belongs to Fol. For routine and accurate differentiation between two morphologically indistinguishable <i>F. oxysporum formae speciales</i> strains, <i>F. oxysporum</i> f. sp. <i>lycopersici</i> and <i>F. oxysporum</i> f. sp. <i>radicis-lycopersici</i>, a molecular method (mtDNA RFLP analysis) was developed, and its usefulness for such differentiation was compared with that of two other methods: isozyme analysis and an osmotic method, revealed with high performance liquid chromatography (HPLC). The HPLC-spectra of Fo-(IMI 386351) had an extra peak for the two tested fractions, indicating that activation of the observed plant defence mechanism could have been at least partially the result of one of the products of the eliciting microbe. Preliminary results obtained by nuclear magnetic resonance spectrometry of those fractions suggest that the extra peak probably represents an oligosaccharide, which may have acted as a mobile signal and triggered the plant defence mechanisms.</p><p>We concluded that (1) our three tested microorganisms are able to stimulate plant defence mechanisms by triggering SIR (plant immunity), (2) the complexity and elaborateness of evolved plant-microbe interactions involving plant defence can, at least in some cases, be observed and studied in the laboratory, and (3) molecular tools can be a powerful means for identifying fungal strains and for clarifying their taxonomical relationships.</p>

Microorganisms, including two fungi, Phytophthora cryptogea and Fusarium oxysporum strain Fo-(IMI 386351), and one bacterium, Pesudomonas sp. strain MF30, were tested for their abilities to stimulate plant defence responses in tomato (Lycopersicon esculentum –L.) and to serve as effective biocontrol agents (Bs). The study included in vivo and in vitro characterization of biological attributes of the microorganisms, pertaining to their abilities to stimulate plant immunity against a fungal pathogen, Fusarium oxysporum f. sp. lycopersici (Fol), the causal agent of tomato wilt disease. Using Lycopersicon esculentum –L. as a model plant for examining some fundamental elements of the plant-microorganism interaction, the study reveals and clarifies some aspects of the close association and the complexity of such systems. For each B, the results revealed a B-distinct plant-microorganism interaction, which included systemic induced resistance (SIR). A phylogenetic analyses of the partial sequences of two Fo-(IMI 386351) genes, a mitochondrial small subunit ribosomal DNA (mtSSU rDNA) and the nuclear translation elongation factor 1α (EF-1α), provided phylogenetic trees confirming that Fo-(IMI 386351) might be a member of Fol or of F. oxysporum f. sp. melonis, which have polyphyletic evolutionary origins. RFLP analysis (mtDNA), suggested that Fo-(IMI 386351) probably belongs to Fol. For routine and accurate differentiation between two morphologically indistinguishable F. oxysporum formae speciales strains, F. oxysporum f. sp. lycopersici and F. oxysporum f. sp. radicis-lycopersici, a molecular method (mtDNA RFLP analysis) was developed, and its usefulness for such differentiation was compared with that of two other methods: isozyme analysis and an osmotic method, revealed with high performance liquid chromatography (HPLC). The HPLC-spectra of Fo-(IMI 386351) had an extra peak for the two tested fractions, indicating that activation of the observed plant defence mechanism could have been at least partially the result of one of the products of the eliciting microbe. Preliminary results obtained by nuclear magnetic resonance spectrometry of those fractions suggest that the extra peak probably represents an oligosaccharide, which may have acted as a mobile signal and triggered the plant defence mechanisms. We concluded that (1) our three tested microorganisms are able to stimulate plant defence mechanisms by triggering SIR (plant immunity), (2) the complexity and elaborateness of evolved plant-microbe interactions involving plant defence can, at least in some cases, be observed and studied in the laboratory, and (3) molecular tools can be a powerful means for identifying fungal strains and for clarifying their taxonomical relationships.

Les endophytes sont des microorganismes (généralement des bactéries et des champignons) qui vivent dans les tissus végétaux mais n'activent pas le système immunitaire/défense des plantes, contrairement aux pathogènes végétaux qui activent généralement les réponses immunitaires des plantes. Des recherches récentes ont montré que pratiquement toutes les plantes cultivées en plein champ contiennent un certain nombre d'endophytes, et que certains endophytes stimulent la croissance des plantes et renforcent la résistance contre les agents pathogènes. Les endophytes sécrètent des composés chimiques (métabolites secondaires) qui suppriment la croissance des agents pathogènes, un processus connu sous le nom de biocontrôle. En raison de ces propriétés de biocontrôle, les endophytes sont une alternative potentielle aux pesticides chimiques pour lutter contre les maladies des plantes. En conséquence, le biocontrôle est devenu un domaine de recherche important. Mon projet de recherche comportait les objectifs spécifiques suivants : (i) isoler les endophytes des plants de canneberges acquis auprès de deux producteurs commerciaux de canneberges de la variété Stevens situés au Québec, Canada (Bieler Cranberries Inc, et Gillivert Inc.) ; (ii) tester l'activité de biocontrôle des endophytes contre une collection de champignons pathogènes et ensuite inoculer les endophytes les plus actifs dans des plants de canneberges obtenus par germination de la variété Stevens (Bieler Cranberries Inc. ) et Scarlet Knight (Daniele Landreville) ; et (iii) identifier des groupes de gènes de métabolites secondaires en séquençant, assemblant et annotant le génome d'un endophyte qui présentait de fortes caractéristiques de biocontrôle. Dans le cadre de ce projet de recherche, des tests antagonistes in vitro ont été réalisés avec des endophytes de la canneberge et un champignon pathogène, qui ont montré que Pseudomonas sp. CSWB3, Pseudomonas sp. CLWB12 et la souche fongique Lachnum sp. EFK28 étaient les plus actifs et ces souches ont donc été sélectionnées pour des études plus approfondies. Des expériences de germination de semis in vitro et d'inoculation d'endophytes ont montré que les souches bactériennes Pseudomonas sp. CSWB3 et Pseudomonas sp. CLWB12 amélioraient la croissance des semis de canneberges de la variété Stevens. Comme les Pseudomonas sp. CSWB3 et Pseudomonas sp. CLWB12 ont tous deux un effet antagoniste élevé sur les champignons pathogènes, un seul (Pseudomonas sp. CSWB3) a été soumis à une analyse du génome. Le séquençage, l'assemblage, l'annotation et l'analyse du génome de Pseudomonas sp. CSWB3 a révélé que cette souche possède cinq groupes de gènes biosynthétiques de métabolites secondaires qui codent pour les protéines responsables de la biosynthèse des composés antifongiques/antimicrobiens : pyrrolnitrine, pyoluteorine, putisolvine, 2,4-diacétylephloroglucinol, bicornutine A1 et bicornutine A2. Sur la base des résultats de ces travaux, nous concluons que certains endophytes de la canneberge qui possèdent des groupes de gènes codant pour des métabolites secondaires antifongiques peuvent supprimer les pathogènes fongiques et améliorer la croissance des plantes. / Endophytes are microorganisms (typically bacteria and fungi) that live within plant tissue but do not activate the plant defense/immune system, unlike plant pathogens that typically do activate plant immune responses. Recent research has shown that virtually all plants grown under field conditions contain a number of endophytes, and that certain endophytes stimulate plant growth and enhance resistance against pathogens. Endophytes secrete chemical compounds (secondary metabolites) that suppress pathogen growth, a process known as biocontrol. Because of these biocontrol properties, endophytes are a potential alternative to chemical pesticides for combatting plant disease. Accordingly, biocontrol has become an important field of research. My research project was comprised of the following specific aims: (i) isolate endophytes from cranberry plants that were acquired from two commercial producers of cranberries of the Stevens variety located in Quebec, Canada (Bieler Cranberries Inc, and Gillivert Inc.); (ii) test the biocontrol activity of endophytes against a collection of fungal pathogens and then inoculate the most active endophytes into cranberry seedlings that were obtained by germinating Stevens (Bieler Cranberries Inc.) and Scarlet Knight (Daniele Landreville) seeds; and (iii) identify secondary metabolite gene clusters by sequencing, assembling, and annotating the genome of one endophyte that exhibited strong biocontrol characteristics. As part of this research project, in vitro antagonistic tests were conducted with cranberry endophytes and fungal pathogen, which showed that Pseudomonas sp. CSWB3, Pseudomonas sp. CLWB12, and the fungal strain Lachnum sp. EFK28 were the most active and therefore these strains were selected for further studies. In vitro seedling germination and endophyte inoculation experiments showed that the bacterial strains Pseudomonas sp. CSWB3 and Pseudomonas sp. CLWB12 enhanced the growth of cranberry seedlings of the Stevens variety. Since Pseudomonas sp. CSWB3 and Pseudomonas sp. CLWB12 both had a high antagonistic effect on fungal pathogens, only one (Pseudomonas sp. CSWB3) was subjected to genome analysis. Sequencing, assembly, annotation, and analysis of the Pseudomonas sp. CSWB3 genome revealed that this strain possesses five secondary metabolite biosynthetic gene clusters that encode proteins responsible for the biosynthesis of the antifungal/antimicrobial compounds pyrrolnitrin, pyoluteorin, putisolvin, 2,4-diacetylephloroglucinol, bicornutin A1, and bicornutin A2. Based on the results of this work, we conclude that certain cranberry endophytes that possess gene clusters encoding antifungal secondary metabolites can suppress fungal pathogens and enhance plant growth.