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Dissertations / Theses on the topic 'Vibrios'

Author: Grafiati
Published: 4 June 2021
Last updated: 11 March 2023

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1

Dias, Graciela Maria. "Genômica comparativa de vibrios." Laboratório Nacional de Computação Científica, 2010. http://www.lncc.br/tdmc/tde_busca/arquivo.php?codArquivo=221.

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Genomas de vibrios ambientais ainda são pouco conhecidos. O presente trabalho de dissertação de mestrado envolveu a anotação de quatro genomas parciais de vibrios ( V. alginolyticus 40B, V. communis 1DA3, V. mimicus VM603 e VM573), a comparação da performance de três sistemas automáticos de anotação de genomas (SABIA, RAST, e GRC) e a determinação de genes putativos únicos de cada um dos quatro genomas. Os genomas de vibrios apresentaram entre 3.745 e 4.977 genes, dos quais em média 2.900 são válidos, 898 são conservados hipotéticos e 385 são hipotéticos. Os genomas apresentaram similaridade em termos de classes de grupos ortólogos com a maioria dos genes válidos identificados nas classes: funções gerais e desconhecidas(R e S), transporte e metabolismo de aminoácidos(E) e transcrição(K) de acordo com as classes de grupos ortólogos (COG) e a maioria das classes foram similares. A comparação entre os anotadores automáticos sugeriu que cada anotador apresenta prós e contras. O anotador SABIA apresenta uma grande interatividade com os bancos de dados biológicos, tais como o InterPro e Swiss-Prot. O anotador RAST é muito útil para comparação genômica do organismo de interesse com os diversos genomas e metagenomas presentes nos bancos públicos, enquanto que o anotador GRC pode ser utilizado localmente, sem a necessidade de acesso à internet. De acordo com as análises comparativas por meio da anotação realizada com o auxílio do BLAST e BLAST Atlas, os genomas de vibrios ( V. alginolyticus 40B, V. communis 1DA3, V. mimicus VM603 e VM573) também apresentaram diferenças em termos de conteúdo gênico, indicando que cada linhagem de vibrio possui sub-grupos de genes únicos. Cada um dos quatro genomas apresentaram de 289 a 1.6432 genes únicos de acordo com o as comparações pareadas com os vizinhos filogenéticos mais próximos disponíveis nos bancos de dados. Assim, a comparação entre os genomas das linhagens V. alginolyticus 40B e V. alginolyticus 12G01 resultou na descoberta de 541 genes únicos na linhagem V. alginolyticus 40B. A comparação entre os genomas de V. communis 1DA3 e V. campbellii ATTC BAA-1116 resultou na descoberta de 1.432 genes únicos na linhagem V. communis 1DA3 e a comparação entre os genomas de V. mimicus VM603 e VM573 resultou na descoberta de 334 e 289 genes únicos, em cada uma destas linhagens. Há um predomínio de genes únicos, sobretudo, pertencentes as classes relacionadas com carboidratos, resposta ao estresse, virulência, aminoácidos e derivados, parede celular e cápsula, sugerindo que estes genes estariam associados com a adaptação das linhagens à diferentes condições ambientais e diferentes nichos ecológicos.
Vibrios genomes are not fully known. This thesis focused on the annotation of four draft genomes ( V. alginolyticus 40B, V. communis 1DA3, V. mimicus VM603 e VM573), the performance comparison of three automated genome annotations (SABIA, RAST and GRC) and the identification of putative unique genes (strain specific genes) in the genomes. The genomes of Vibrios contained between 3,745 and 4,977 genes, of which 2,900 were real genes, 898 were hypothetic conserved genes and 385 were hypothetic genes. The majority of known gene products were related to general functions and unknown functions (R and S), metabolism and amino acid transport (E) and transcription (K) on the basis of the COG (clusters of ortologs group). The comparison of three automated genome annotation systems indicated that each system had advantages and disadvantagens. The SABIA Server revealed interactivity with many biologic databases, such as InterPro and Swiss-Prot. The RAST server was useful for comparative genomics of specific genomes and metagenomes. The GRC server was useful annotation offline as it can be installed and run on a local computer. The genomes of Vibrios showed differences in the genic content revealled by BLAST atlas and BLAST. Each genome showed 289 to 1,432 unique genes, resulting of comparisons with organisms phylogenetically closest related. The comparison of the genomes of V. alginolyticus 40B and V. alginolyticus 12G01 revealed that 40B has 541 unique genes. The comparison of V. communis 1DA3 and V. campbellii ATTC genome revealed 1,432 unique genes in 1DA3. V. mimicus VM573 and VM603 genomes showed 334 and 289 unique genes, respectively. The vast majority of unique genes were related with carbohidrates, stress response, virulence, cell wall and capsule, indicating that this sub-group of genes may be associated with adaptation of strains to differents habitats and ecologic niches.
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2

Campeão, Mariana Esteves. "Diversidade genômica e diagnostico fenotípico de vibrios." Laboratório Nacional de Computação Cientifica, 2014. https://tede.lncc.br/handle/tede/184.

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Vibrios sao bacterias amplamente distribuidas no meio aquatico e podem ser encontradas em associacao com organismos marinhos, tanto como causadores de doencas quanto como simbiontes. O advento das tecnicas de sequenciamento de nova geracao e de alto desempenho tem possibilitado o acesso cada vez mais amplo a dados genomicos microbianos, incluindo vibrios. Tal quantidade e disponibilidade de dados permitem analises in silico, que podem compreender desde caracteristicas genomicas ate fenotipicas. A taxonomia microbiana e fundamentada na abordagem polifasica, que mede as relacoes evolutivas a partir do uso de sequencias de genes, especialmente o RNAr 16S, similaridade genomica, por meio de hibridizacao de DNA, e ampla caracterizacao fenotipica. A caracterizacao fenotipica requer testes experimentais, que muitas vezes sao demorados, caros e requerem grande experiencia. Neste estudo propomos o uso de genomas para a analise da diversidade e identificacao fenotipica de vibrios. Para tanto, foram avaliadas caracteristicas basicas de vibrios (tais como tamanho do genoma, conteudo genico e posicao logenetica); analisaram-se genes unicos e suas possiveis funcoes ecologicas; e desenvolveu-se uma ferramenta prototipo para identificacao de fenotipos diagnosticos de vibrios, denominada vibriophenotyping 1.0. A logenia construida a partir do genoma minimo recuperou os diferentes generos e clados descritos na literatura para o grupo vibrio, bem como posicionou as especies consideradas irmas em relacao a um ancestral comum proximo. Os genes unicos, por sua vez, puderam ainda revelar peculiaridades entre especies irmas. Por m, o programa de identificacao fenotipica desenvolvido foi testado com genomas de linhagens tipo de vibrios e apresentou uma media de similaridade superior a 70% entre os fenotipos obtidos in vitro e in silico, sendo alcançada uma similaridade de 100% para genomas integros. Dessa forma, concluiu-se que analises do pangenoma permitem a recontrucao logenetica dentro do grupo vibrios e a identificacao de genes unicos relevantes para o papel ecologico da especie no ambiente de origem, e, ainda, que a identificacao fenotipica atraves da automatizacao por uma ferramenta computacional e possivel a partir da analise de genomas.
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3

Rubio, Galleguillos Felipe Andrés. "Implementación de técnica para la detección de vibrios y análisis de Vibrio vulnificus en muestras de alimentos." Tesis, Universidad de Chile, 2006. http://repositorio.uchile.cl/handle/2250/105607.

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Unidad de práctica para optar al título de Químico Farmacéutico
No autorizada por el autor para ser publicada a texto completo en el Portal de Tesis Electrónicas
La practica prolongada fue realizada en Departamento de Microbiología de Alimentos del Instituto se Salud Pública de Chile, durante los meses de Junio a Diciembre del año 2005. Mi labor en la práctica constó de tres etapas simultáneas: La primera consistió en recibir capacitación durante todo el período de mi práctica, en detección y cuantificación de los patógenos bacterianos más frecuentes encontrados en alimentos. La segunda etapa fue implementar el último método de detección de Vibrios (principalmente Vibrio vulnificus en mi caso) según el Manual Analítico Bacteriológico (BAM) año 2004 impuesto por la Food and Drugs Administration (FDA) (1), para la cual se utilizaron cepas de diversos Vibrios tales como Vibrio vulnificus, Vibrio parahaemolyticus, Vibrio cholerae, etc. Dicha labor será necesaria para actualizar los métodos de detección en los laboratorios de la red de vigilancia epidemiológica de Chile. En la otra etapa, se evaluó según el método que se estaba desarrollando la población de Vibrio vulnificus existente en Puerto Montt, ésta etapa se comenzó a trabajar a partir aproximadamente en julio ya que primero debía estar desarrollada en alguna medida la técnica de detección, además de que estuvieran los materiales necesarios para el trabajo. Las muestras analizadas son ensayos de rutina que llegan al SEREMI de Salud de la región Metropolitana para evaluar durante todo el año la población de Vibrio parahaemolyticus y Vibrio cholerae en Puerto Montt, las cuales se reciben todos los martes y consta de 5 muestras de los cuales se analizan 12 especimenes de cada una, para luego cuantificarlas por el método de tubos múltiples según la tabla de número más probable (anexo, Tabla 1). Es importante que el ISP, como centro de referencia posea información sobre todo patógeno que pueda ser encontrado en alimentos, es por eso que esta etapa culminará con la entrega del procedimiento de detección de Vibrio vulnificus al Departamento de Microbiología de Alimentos
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4

Robino, Etienne. "Etude des amibes marines et de leurs interactions avec les vibrios pathogènes d’huître." Thesis, Montpellier, 2019. http://www.theses.fr/2019MONTG041.

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Les amibes libres dans les environnements aquatiques utilisent la phagocytose des bactéries pour leur nutrition. Selon l’hypothèse de l’évolution fortuite de la virulence, les mécanismes cellulaires et moléculaires de la phagocytose étant conservés des amibes aux cellules immunitaires des animaux, la prédation exercée par les amibes pourraient favoriser l’émergence de bactéries pathogènes résistantes à la phagocytose. Depuis 2008, les huîtres creuses Crassostrea gigas sont victimes d’épisodes de surmortalités en France. Cette pathologie poly-microbienne implique le virus Herpes OsHV-1 µvar qui provoque une immunosuppression des huîtres qui sont alors colonisées par divers bactéries pathogènes opportunistes dont des vibrios induisant la mort de l’animal. V. tasmaniensis LGP32 est un pathogène intracellulaire facultatif des hémocytes d’huître qui résiste à la phagocytose et détruit les hémocytes en utilisant un certain nombre de facteurs de virulence. Nous avons donc entrepris d’étudier les interactions entre les amibes libres de l’environnement ostréicole et les vibrios afin de vérifier si certains mécanismes de virulence pouvaient aussi jouer un rôle dans ce type d’interactions. En réalisant des échantillonnages sur le terrain, nous avons mis en évidence que l’interaction entre vibrios et amibes est écologiquement réaliste, et observé une faible diversité de protistes hétérotrophes près des tables ostréicoles de la lagune de Thau par rapport à d’autres environnements moins anthropisés. Des études fonctionnelles entre LGP32 et l’amibe Vannella sp. AP1411 ont montré que LGP32 est capable de résister à la prédation par les amibes impliquant certains facteurs de virulence comme la métalloprotéase Vsm et la pompe d’efflux du cuivre de type P-ATPase CopA qui sont aussi impliqués dans l’interaction de LGP32 avec les huîtres. En revanche, d’autres facteurs de virulence impliqués chez l’huître ne le sont pas dans la résistance à la prédation par les amibes indiquant que certains facteurs sont impliqués dans des interactions avec divers hôtes tandis que d’autres seraient impliqués dans des interactions plus spécifiques
Free living amoebae inhabit aquatic environments and use phagocytosis of bacteria for their nutrition. According to the hypothesis of coincidental evolution of virulence, the cellular and molecular mechanisms of phagocytosis being preserved from amoebae to the immune cells of animals, the predation exerted by amoebae could favor the emergence of pathogenic bacteria resistant to phagocytosis. Since 2008, Crassostrea gigas oysters have suffered from over-mortality in France. This poly-microbial disease involves the Herpes OsHV-1 μvar virus which causes an immunosuppression of oysters that are then colonized by various opportunistic pathogenic bacteria including vibrios inducing the death of the animal. V. tasmaniensis LGP32 is a facultative intracellular pathogen of oyster hemocytes that resists phagocytosis and destroys hemocytes using different virulence factors. We have therefore undertaken to study the interactions between marine amoebae of the oyster environment and the vibrios in order to verify if some mechanisms of virulence could also play a role in this type of interactions. By performing field sampling, we demonstrated that the interaction between vibrios and amoebae is ecologically realistic and observed a low diversity of heterotrophic protists near the oyster tables of the Thau Lagoon compared to other less anthropogenic environments. Functional studies between LGP32 and the amoeba Vannella sp. AP1411 showed that LGP32 is able to resist amoeba predation involving certain virulence factors such as Vsm metalloprotease and CopA P-ATPase copper efflux pump which are also involved in the interaction of LGP32 with oysters. In contrast, other virulence factors implicated in the oyster are not involved in amoeba-predation resistance indicating that some factors are involved in interactions with various hosts while others would be involved in more specific interactions
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5

Oyanedel, Trigo Daniel. "Bases moléculaires et cellulaires des interactions Vibrios Crassostrea gigas en contexte sain et pathologique." Thesis, Montpellier, 2020. http://www.theses.fr/2020MONTG032.

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Les bactéries du genre Vibrio sont ubiquitaires dans les milieux aquatiques. Elles adoptent des modes de vie libres et associés. Elles établissent des symbioses mutualistes, commensales et parasitaires avec de nombreux métazoaires. Chez l'huître Crassostrea gigas saine, un microbiote abondant et diversifié qui comprend de nombreux Vibrio est maintenu sous homéostasie immunitaire. Toutefois, sous l'influence de stress biotiques ou abiotiques une dysbiose se crée favorisant la prolifération d'espèces opportunistes de Vibrio qui peuvent induire la mort des huîtres. C’est notamment le cas lors du syndrome de mortalité des huîtres du Pacifique (POMS) provoqué par un virus immunosuppresseur, OsHV-1 µvar. Nous avons ici caractérisé les interactions Vibrio / C. gigas en contexte sain et pathologique. Nous montrons que chez des populations de V. splendidus associées à des huîtres saines, la virulence et la capacité de colonisation peuvent être contraintes par la sélection de structures de l’antigène O qui sont plus facilement reconnues par le système immunitaire de l'hôte mais qui confèrent une résistance au broutage par des amibes marines. Ce compromis entre la capacité à coloniser son hôte et la persistance environnementale est vraisemblablement à l’origine de la grande diversité structurale observée pour l’antigène O dans cette espèce. En contexte pathologique, nous avons montré que les espèces associées à l’huître sont en grande majorité cytotoxiques pour les cellules immunitaires de leur hôte, et ce, quel que soit l’environnement considéré (Atlantique, Méditerranée). Cette cytotoxicité est un déterminant clé de l’échappement aux puissantes défenses cellulaires de l’huître et du succès infectieux. Nous avons observé que les bases moléculaires de la cytotoxicité sont spécifiques à chaque espèce de Vibrio étudiée. Enfin, au-delà des agents pathogènes opportunistes qui utilisent la cytotoxicité (V. tasmaniensis, V. crassostreae, V. splendidus, V. harveyi), nous avons identifié de simples opportunistes, comme V. rotiferianus, qui non seulement bénéficient de l'activité immunosuppressive des autres agents pathogènes mais également adoptent des stratégies d'acquisition non coopérative de biens publics, tels que les sidérophores produits par la communauté microbienne hébergée par leur hôte
Bacteria of the genus Vibrio are ubiquitous in aquatic environments. They adopt free and associated lifestyles. They establish mutualistic, commensal and parasitic symbioses with numerous metazoa. In the healthy Crassostrea gigas oyster, an abundant and diverse microbiota that includes many Vibrio is maintained under immune homeostasis. However, under the influence of biotic or abiotic stressors a dysbiosis is created favoring the proliferation of opportunistic Vibrio species, which can induce the death of oysters. This occurs during the Pacific Oyster Mortality Syndrome (POMS), which is caused by an immunosuppressive virus, OsHV-1 µvar. We have here characterized the Vibrio / C. gigas interactions in health and disease. We show that in populations of V. splendidus associated with healthy oysters, virulence and colonization capacity can be constrained by the selection of O-antigen structures that are more easily recognized by the host immune system but which confer resistance to grazing by marine amoebae. This trade-off between the ability to colonize its host and environmental persistence is likely the cause of the great structural diversity observed for the O-antigen in this species. In a pathological context, we have shown that the species associated with the oyster are for the most part cytotoxic for the immune cells of their host, regardless of the environment considered (Atlantic, Mediterranean). This cytotoxicity is a key determinant of the escape from the oyster's powerful cellular defenses and determines the infectious success. We observed that the molecular bases of cytotoxicity are specific to each Vibrio species studied. Finally, beyond opportunistic pathogens that use cytotoxicity (V. tasmaniensis, V. crassostreae, V. splendidus, V. harveyi), we have identified simple opportunists, such as V. rotiferianus, which not only benefit from the immunosuppressive activity of other pathogens but also adopt strategies of non-cooperative acquisition of public goods, such as siderophores produced by the microbial community hosted by their host
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6

Silveira, Ana Cristina Gomes. "Identification of Non-Coding RNAS in Marine Vibrios." Laboratório Nacional de Computação Científica, 2010. http://www.lncc.br/tdmc/tde_busca/arquivo.php?codArquivo=212.

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The discovery of the non-coding RNA (ncRNA) has been primarily focused on the genomes of eukaryotes and pathogenic bacteria. In vibrios, all that is known up to now regarding ncRNAs involves V. cholerae N16961 e V. campbellii ATCC BAA-1116. In this study, ncRNA candidate genes were identified in the genomes of V. campbellii ATCC BAA-1116, V. alginolyticus 40B, V. communis 1DA3 e V. mimicus VM573. V. alginolyticus 40B and V. campbellii ATCC BAA-1116 are abundant in brazilian corals, whereas V. mimicus VM573 is a toxic strain (carrying the Vibrio pathogenicity island) atypical to this species. In order to identify the ncRNAs in silico, the tools Infernal and Rfam database were used. Perl programs were developed in the present work. The Infernal tool and the Rfam database are based on the Covariance Model (CM), a special case of Stochastic Context Free Grammars (SCFG). Up to 38 ncRNAs were identified per species. They were classified into seven classes according to their regulatory function and/or structural (1. riboswitches, 2. modulators of protein activity, 3. RNA's antisensus of trans action, 4. RNA's antisensus of cis action, 5. ribonucleoproteins, 6. regulation by transcription termination and 7. unknown classification). The most abundant group was the riboswitch, whereas the less abundant group was the ribonucleoprotein. This work demonstrated that the ncRNAs show a great diversity in functional classes, possibly associated with the regulation of different cellular processes in vibrios, including regulation of pathogenicity.
A descoberta de RNA não-codificante (ncRNA) tem focado principalmente nos genomas de eucariontes e de bactérias patogênicas. Em vibrios, o que se conhece até o momento sobre ncRNAs envolve V. cholerae N16961 e V. campbellii ATCC BAA-1116. Neste estudo, são identificados genes candidatos de ncRNAs no genoma de V. campbellii ATCC BAA-1116, V. alginolyticus 40B, V. communis 1DA3 e V. mimicus VM573. V. alginolyticus 40B e V. campbellii ATCC BAA-1116 são abundantes em corais brasileiros, enquanto que V. mimicus VM573 é uma linhagem toxigênica (CT e TCP positiva) atípica desta espécie. Para identificar os ncRNAs através de análise in silico foram utilizadas ferramentas já disponíveis (Infernal e a base de dados Rfam) e programas em Perl desenvolvidos no presente trabalho. A ferramenta Infernal e a base de dados Rfam são baseados em modelo de covariância (CM), um caso especial de gramáticas estocásticas livres de contexto (SCFG). Foram identificados até 38 ncRNAs por espécie, os quais foram classificados em sete classes de acordo com sua função regulatória e /ou estrutural (riboswitches, moduladores da atividade de proteínas, RNAs antisenso de ação trans, RNAs antisenso de ação cis, ribonucleoproteinas, regulação por término de transcrição e classificação desconhecida). O grupo mais abundante foi o riboswitch, enquanto que o grupo menos abundante foi o ribonucleoproteina. Este trabalho demonstrou que os ncRNAs apresentam uma ampla diversidade de classes funcionais, estando possivelmente associados com a regulação de diferentes processos celulares em vibrio, incluindo a regulação da patogenicidade.
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7

Matte, Glavur Rogerio. "Isolamento de vibrios potencialmente patogênicos em moluscos bivalves." Universidade de São Paulo, 1994. http://www.teses.usp.br/teses/disponiveis/6/6134/tde-14072016-152410/.

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Neste estudo, 26 amostras de ostras (Crassostrea gigas) comercializadas na cidade de São Paulo e em alguns pontos do litoral de São Paulo, e 36 amostras de mexilhões (Perna perna) colhidas mensalmente em 3 pontos do litoral de Ubatuba - SP, foram submetidas à pesquisa de vibrios potencialmente patogênicos. As amostras desses moluscos eram submetidas a enriquecimento em água peptonada alcalina sem cloreto de sódio e com 1 por cento de cloreto de sódio, e GSTB. O isolamento foi realizado em ágar TCBS. Colônias sacarose positivas e negativas, sugestivas de espécies de Vibrio foram identificadas presuntivamente em meio de ágar ferro de Kligler, sendo confirmadas através de provas bioqufmicas complementares. Uma parte das amostras de vibrios potencialmente patogênicos isoladas foi submetida ao teste de Dean e teste de alça ligada em íleo de coelhos. Os vibrios potencialmente patogênicos encontrados em amostras de ostras foram V. alginolyticus (81 por cento ), V.parahaemolyticus (77 por cento ), V. cholerae não 0:1 (31 por cento ), V. fluvialis (27 por cento ), V. furnissii (19 por cento ), V. mimicus (12 por cento ) e V. vulnificus (12 por cento ) e em amostras de mexilhões foram V. alginolyticus(97 por cento ), V. parahaemolyticus(75 por cento ), V. fluvialis (47 por cento ), V. vulnificus (11 por cento ), V. cholerae não 0:1 (6 por cento ), V. furnissii (6 por cento ) e V. mimicus (6 por cento ). Observou-se acúmulo de fluido em alça ligada de íleo de coelho entre 0,25 e 0,49 ml/cm em 6,9 por cento das amostras, entre 0,5 e 0,99 ml/cm em 15,6 por cento e maior ou igual a 1 ml/cm em 15,1 por cento , e/ou intestino de camundongos lactentes (Teste de Dean) em 26,6 por cento das amostras testadas, confirmando o elevado potencial desses microrganismos em causar gastrenterite. Verificou-se ausência de variação sazonal e também, de correlação entre os vibrios potencialmente patogênicos isolados e os indicadores de contaminação fecal, confirmando que a presença desses microrganismos ocorre de forma autóctone e que, as condições climáticas foram favoráveis à sobrevivência dessas espécies em todas as épocas do ano. Considerando-se os resultados obtidos no presente estudo e o fato de que ostras e mexilhões são habitualmente ingeridos crus ou insuficientemente cozidos, pode-se concluir que sua ingestão constitui-se em um determinado grau de risco para a saúde do consumidor.
In this work, 26 oysters samples (Crassostrea gigas), found in the market of São Paulo city and some coastal areas of São Paulo State, and 36 mussels samples (Perna perna), that were collected monthly in 3 coastal areas of Ubatuba city - SP., were analyzed for the potential patogenic vibrios occurrence. Samples were enriched in alcalin peptone water with (1 per cent ) and without sodium cloride and GSTB. Isolation was performed on TCBS agar. suspect sacharosis positive and negative colonies, resembling vibrio species, were presumptively identified on Kligler iron agar, and confirmed by complementary biochemical tests. Some of this potential patogenic vibrios were submitted to suckling mouse assay and rabbit ileal loop assay. Potential patogenic vibrios isolated from oyster samples were: V. alginolyticus (81 per cent ), V. parahaemolyticus (77 per cent ), V. cholerae non 0:1 (31 per cent ), V. fluvialis (27 per cent ) I V. furnissii (19 per cent ), V. mimicus (12 per cent ) and V. vulnificus (12 per cent ) and from mussels samples were: V. a.1ginolyticus (97 per cent ), V. parabaemolyticus (75 per cent ), V. fluvialis (47 per cent ), V. vulnificus (11 per cent ), V. cholerae non 0:1 (6 per cent ), V. furnissii (6 per cent ) and V. mimicus (6 per cent ). It was found 6,9 per cent of samples between 0,25 and 0,49 ml/cm of fluid accumulation in ileal loop assay, 15,6 per cent between 0,5 and 0,99 ml/cm and 15,1 per cent was equal or higher than 1 ml/cm. Among the samples assayed for suckling mouse 26,6 per cent were positive. These results confirm the high potential of these microrganisms to induce gastroenteritis. Seasonal variation as well as correlation between the potential patogenic vibrios isolated and the fecal contamination indicators were not found, confirming that the presence of such microrganisms occurs autochthonously and that the climate conditions were favourable to these species survival during the whole year. with the results of this work and considering that oyster and mussels are usually ingested raw or insufficiently cooked, the conclusion is that the ingestion of such mollusks presents a certain degree of risk for the consumer\'s health.
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8

Silveira, Ana Cristina Gomes. "Identificação de RNAs não-codificantes em vibrios marinhos." Laboratório Nacional de Computação Científica, 2010. https://tede.lncc.br/handle/tede/13.

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The discovery of the non-coding RNA (ncRNA) has been primarily focused on the genomes of eukaryotes and pathogenic bacteria. In vibrios, all that is known up to now regarding ncRNAs involves V. cholerae N16961 e V. campbellii ATCC BAA-1116. In this study, ncRNA candidate genes were identified in the genomes of V. campbellii ATCC BAA-1116, V. alginolyticus 40B, V. communis 1DA3 e V. mimicus VM573. V. alginolyticus 40B and V. campbellii ATCC BAA-1116 are abundant in brazilian corals, whereas V. mimicus VM573 is a toxic strain (carrying the Vibrio pathogenicity island) atypical to this species. In order to identify the ncRNAs in silico, the tools Infernal and Rfam database were used. Perl programs were developed in the present work. The Infernal tool and the Rfam database are based on the Covariance Model (CM), a special case of Stochastic Context Free Grammars (SCFG). Up to 38 ncRNAs were identified per species. They were classified into seven classes according to their regulatory function and/or structural (1. riboswitches, 2. modulators of protein activity, 3. RNA's antisensus of trans action, 4. RNA's antisensus of cis action, 5. ribonucleoproteins, 6. regulation by transcription termination and 7. unknown classification). The most abundant group was the riboswitch, whereas the less abundant group was the ribonucleoprotein. This work demonstrated that the ncRNAs show a great diversity in functional classes, possibly associated with the regulation of different cellular processes in vibrios, including regulation of pathogenicity.
A descoberta de RNA não-codificante (ncRNA) tem focado principalmente nos genomas de eucariontes e de bactérias patogênicas. Em vibrios, o que se conhece até o momento sobre ncRNAs envolve V. cholerae N16961 e V. campbellii ATCC BAA-1116. Neste estudo, são identificados genes candidatos de ncRNAs no genoma de V. campbellii ATCC BAA-1116, V. alginolyticus 40B, V. communis 1DA3 e V. mimicus VM573. V. alginolyticus 40B e V. campbellii ATCC BAA-1116 são abundantes em corais brasileiros, enquanto que V. mimicus VM573 é uma linhagem toxigênica (CT e TCP positiva) atípica desta espécie. Para identificar os ncRNAs através de análise in silico foram utilizadas ferramentas já disponíveis (Infernal e a base de dados Rfam) e programas em Perl desenvolvidos no presente trabalho. A ferramenta Infernal e a base de dados Rfam são baseados em modelo de covariância (CM), um caso especial de gramáticas estocásticas livres de contexto (SCFG). Foram identificados até 38 ncRNAs por espécie, os quais foram classificados em sete classes de acordo com sua função regulatória e /ou estrutural (riboswitches, moduladores da atividade de proteínas, RNAs antisenso de ação trans, RNAs antisenso de ação cis, ribonucleoproteinas, regulação por término de transcrição e classificação desconhecida). O grupo mais abundante foi o riboswitch, enquanto que o grupo menos abundante foi o ribonucleoproteina. Este trabalho demonstrou que os ncRNAs apresentam uma ampla diversidade de classes funcionais, estando possivelmente associados com a regulação de diferentes processos celulares em vibrio, incluindo a regulação da patogenicidade.
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Chen, Desheng, and chen desheng@deakin edu au. "Development of monoclonal antibodies against Vibrio pathogens." Deakin University. Department of Biological Science, 1991. http://tux.lib.deakin.edu.au./adt-VDU/public/adt-VDU20080626.140825.

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Monoclonal antibodies were developed against pathogenic vibrios for use in rapid identification in disease situations of humans, fish and shellfish. Of the 12 fusions performed using V. alginolyticus, V. anguillarum, V. carchariae, V. cholerae, V. damsela, V. furnissii, V. harveyi, V. ordalii, V. parahaemolyticus and V. vulnificus, a total of 102 hybridomas were obtained. Based on cross-reactivity of a wide range of Vibrio strains and other gram-negative bacteria, three broad types of monoclonal antibodies were found. The three categories were: (1) ones that were species-specific or specific to a particular surface antigen, (2) a large number that reacted with several Vibrio species, and (3) three that reacted with most Vibrio strains but no other gram-negative bacteria. Each species-specific monoclonal antibody only recognized its corresponding Vibrio species and was used for identifying unknown species, confirming diagnosis of clinical isolates. In addition, several monoclonal antibodies only cross-reacted with similar Vibrio species, e.g. V. parahaemolyticus and V. alginolyticus which share a common H-antigen. Monoclonal antibodies reacting with several Vibrio species were not of particular use in diagnostic situations. Three monoclonal antibodies of the last group did not react with other genera of the family Vibrionaceae, namely Aeromonas, Photobacterium and Plesiomonas nor a wide range of gram-negative enteric bacteria. These data indicated the existence of an antigenic surface determinant common to Vibrio species. One monoclonal reacted with the heat-stable antigenic determinants on the cell surface as v as lipopolysaccharide extracted from all the vibrios studied, thus making it useful for large- scale screening of acute infections of vibrios. In a blind test, seven Vibrio species, isolated from 6 marine and a freshwater source were identified by two laboratories using phenetic tests. Results of immunotyping using monoclonals, three of seven were diagnosed as the same species, another three were designated as Vibrio species but could not be classified further due to the library not having the corresponding monoclonal, and one was diagnostically questionable. Two further tests were carried out. An unknown Vibrio formalin-fixed isolated from diseased marine animal was identified as V. parahaemolyticus by ELISA and FITC. Clinical human isolates of V. alginolyticus, V. parahaemolyticus and V. vulnificus were confirmed by monoclonals. Australian isolates of V. anguillarum appeared to be mostly of serotype O1. monoclonals raised to V. anguillarum AFHRL 1 reacted with only serotype O1 from Denmark but also most Australian isolates. All vibrios pathogenic to fish and shellfish, i.e. V. anguillarum, V. ordalii, V. alginolyticus, V. carchariae, V. cholerae, V. damsela, V. harveyi, V. parahaemolyticus and V. vulnificus, were used for attachment studies to fish cells using phase contrast and FITC-immunofluorescence microscopy. Of these vibrios, V. anguillarum, V. ordalii and V. perahaemolyticus, were found to adhere to different cells and tissues of rainbow trout while others did not appear to attach. However, attachment was inhibited by monoclonal antibodies specific to only these three vibrios. Lipopolysaccharide is well known as being a contributing factor in pathogenicity of gram-negative bacteria. PAGE electrophoresis of extracted LPS from 9 strains covering 6 Vibrio species showed the presence of a common 15,000 D fragment. This fragment was verified by immunoblotting with a genus-specific monoclonal antibody (i.e. F11P411F) recognizing nearly all vibrios. The common LPS fragment was separated and used to raise polyclonal antisera in mouse which reacted strongly with LPS itself, live as well as sodium azide-killed vibrios, but not with other gram-negative bacteria. This raised the possibility of developing vaccine from Vibrio LPS. Monoclonal antibodies developed in the present study enabled rapid identification of a number of pathogenic Vibrio species. There is still further work to produce monoclonal antibodies against additional vibrios that are probably pathogenic. These included V. fluvialis, V. hollisae, V. metschnikovii, V. minicus, V. salmonella and V. tubiashii. Together the application will be of significance in clinical diagnostic work, in the monitoring of vibriosis in fish farms and in quarantine.
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TASSISTRO, GIOVANNI. "Vibrios involved in Crassostrea gigas infections during mass mortality episodes." Doctoral thesis, Università degli studi di Genova, 2019. http://hdl.handle.net/11567/944830.

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11

Collin, Betty. "Characterization and persistence of potential human pathogenic vibrios in aquatic environments." Doctoral thesis, Högskolan Kristianstad, Sektionen för lärande och miljö, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:hkr:diva-9789.

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Vibrio spp., natural inhabitants of aquatic environments, are one of the most common causes of bacterial gastroenteritis in the world, being spread to humans via the ingestion of seafood, contaminated drinking water or exposure to seawater. The majority of Vibrio spp. are avirulent, but certain strains may sporadically be human pathogenic. Vibrio cholerae may cause cholera and fatal wound infections, Vibrio parahaemolyticus may cause gastroenteritis and Vibrio vulnificus may cause wound infections and sepsis. To expand current knowledge of the occurrence, ecological niche and persistence of potential human pathogenic Vibrio spp. in aquatic environments, occurrence and laboratory studies were performed. The seasonal variation of Vibrio spp. in clams and mussels from Mozambique and Sweden were studied, with isolated strains characterized and compared with those isolated from water samples collected in India. Results showed that the numbers of Vibrio spp. in Mozambican clams peaked during the warmer rainy season and that the dominating species was V. parahaemolyticus. Biochemical fingerprinting and virulence screened by PCR revealed a high similarity among strains from the different aquatic environments. However, isolate functional hemolytic analyses and antibiotic resistance patterns differed between strains; Swedish and Indian strains were less sensitive to the tested antibiotics and had a lower hemolytic capacity than those from Mozambique. Molecular analysis of bacterial DNA from Swedish mussels showed the presence of the three Vibrio spp. most commonly linked with human illness, as well as their associated virulence genes. The strains isolated from marine and clinical environments were equally and highly harmful to the tested eukaryotic cells. The persistence of clinical V. cholerae in aquatic environments was investigated in vivo. Strains were exposed to mussels, with bacterial uptake and elimination then examined. The mussels were able to avoid the most potent strain by complete closure of shells. The less potent strain was accumulated in mussel tissue in low levels and one marine control strain to a higher degree. Mussels eliminated the pathogenic strain less efficiently than they did the marine strain. One clinical and one marine strain were then exposed to 4°C for 21 days, with the temperature then increased to 20°C. The clinical strain was more prone to lose culturability than the marine strain at 4°C, the former performed significantly better in regaining culturability after the temperature up-shift. Subsequently, the persistence of the clinical strain in natural bottom sediment, incubating as above, was studied and results showed a similar decrease in culturable numbers in the sediment as in the water. As the clinical V. cholerae strains did not carry any of the standard set of virulence genes, the ability to change from non-culturable to culturable may be of great importance to strain pathogenicity. The results also show that natural bottom sediment may be a potential reservoir of human pathogenic Vibrio spp.
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Augusto, Dora Susana Castro Rodrigues. "Teores de vibrios halófilos patogénicos humanos em ostras, por NMP-PCR." Master's thesis, Universidade de Aveiro, 2007. http://hdl.handle.net/10773/737.

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Mestrado em Microbiologia
O presente estudo foi levado a cabo com o objectivo de determinar a ocorrência e os níveis de Vibrio vulnificus, Vibrio parahaemolyticus (total e potencialmente patogénico) em ostras naturalmente contaminadas, usando dois métodos diferentes de Número Mais Provável (NMP) em conjugação com a técnica de reacção em cadeia da polimerase (PCR) de modo a seleccionar o mais apropriado para análise de rotina. As ostras foram adquiridas em lojas e supermercados locais. Os valores de V. vulnificus (portador do gene que codifica a hemolisina/citolisina da bactéria - vvhA), V. parahaemolyticus total (portador do gene específico da espécie – toxR) e V. parahaemolyticus potencialmente patogénico (portador dos genes que codificam as hemolisinas directa termoestável – tdh e directa termoestável relacionada – trh) foram determinados usando dois métodos de NMP-PCR: (1) enriquecimento em água peptonada alcalina (APW) seguido de PCR (APW-PCR); e (2) enriquecimento em APW e isolamento em agar de tiossulfato citrato bílis sacarose (TCBS) seguido de confirmação das estirpes por PCR (TCBS-PCR). Foi detectado V. vulnificus em quatro amostras de ostras pelo método APWPCR e em três amostras pelo método TCBS-PCR, mas nunca nas mesmas amostras. Foi possível encontrar V. parahaemolyticus em 14 amostras pelo método APW-PCR e em 13 amostras pelo método TCBS-PCR. Quanto aos factores de virulência, foi possível detectar o gene tdh em uma amostra somente pelo método APW-PCR; o gene trh foi detectado em cinco amostras por ambos os métodos, mas nem sempre na mesma amostra. O método APW-PCR demonstrou ser o mais adequado para detectar a presença de V. parahaemolyticus total em ostras, uma vez que gerou maior número de amostras positivas e detectou teores mais elevados, no entanto, recomenda-se o recurso a ambos os métodos para a detecção dos factores de virulência do V. parahaemolyticus e para a detecção de V. vulnificus. ABSTRACT: The present study was carried out to determine the occurrence and levels of Vibrio vulnificus and total and potentially pathogenic Vibrio parahaemolyticus bacteria in naturally contaminated oysters, using two Most Probable Number – Polymerase Chain Reaction (MPN-PCR) different methods in order to select the most appropriate for routine analysis. Oysters were collected from local stores and supermarkets. V. vulnificus (carrying the hemolysin/ cytolysin vvhA gene), total V. parahaemolyticus (carrying the species-specific toxR gene) and potentially pathogenic (carrying the thermostable direct hemolysin - tdh and TDH-related hemolysin - trh genes) V. parahaemolyticus were enumerated by two MPN-PCR methods: (1) Alkaline Peptone Water (APW) enrichment followed by PCR (APW-PCR); and (2) APW enrichment plus isolation on Thiosulfate Citrate Bile Sucrose (TCBS) agar followed by PCR strain confirmation (TCBS-PCR). V. vulnificus was found in four oyster samples by the APW-PCR method and in three by the TCBS-PCR method, but never in the same samples. V. parahaemolyticus was found in 14 oyster samples by the APW-PCR method and in 13 by the TCBS-PCR method. Concerning virulence factors, tdh positive organisms were only detected by the APW-PCR method in one sample; trh positive organisms were found in five oyster samples by both methods though not always in the same sample. The APW-PCR method has shown to be more adequate for the detection of total V. parahaemolyticus in oysters, since it yielded a larger number of positive samples, however, for detection of V. parahaemolyticus virulence factors and V. vulnificus, both methods should be used.
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13

Ostrander, Vicki C. "Survival of Vibro vulnificus and other Vibrios in raw oysters (Crassostrea virginica) during processing in Virginia and cold storage." Thesis, This resource online, 1996. http://scholar.lib.vt.edu/theses/available/etd-11012008-063712/.

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14

Daccord, Aurélie. "Étude de la mobilité d'une nouvelle classe d'îlots génomiques chez les vibrios." Thèse, Université de Sherbrooke, 2013. http://hdl.handle.net/11143/6543.

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Chaque année, de nombreux génomes bactériens sont séquencés et il devient de plus en plus évident que la participation des îlots génomiques à la plasticité bactérienne est prépondérante. Pourtant, bien que la définition même des îlots génomiques implique qu'ils aient été acquis par transfert horizontal, le mécanisme de transfert de nombre d'entre eux demeure inconnu. L'un des mécanismes employés par les îlots génomiques pour se transférer est le transfert conjugatif. Le but de ce projet de recherche était d'étudier le mécanisme de mobilisation d'une nouvelle classe d'îlots génomiques, initialement identifiés dans les genres Vibrio et Alteromonas. Les résultats obtenus ont permis la caractérisation d'un mécanisme de mobilisation inédit reposant sur la reconnaissance par un élément intégratif et conjugatif (ICE) d'une séquence similaire à son origine de transfert sur des îlots génomiques. Grâce à cette reconnaissance spécifique, ces îlots génomiques sont mobilisables par les ICE de la famille SXT/R391, retrouvés principalement chez Vibrio. Cette étude présente l'ensemble du mécanisme de mobilisation des îlots génomiques mobilisables (MGI) par les ICE SXT/R391 à partir de l'excision du chromosome de la cellule donneuse jusqu'à l'intégration dans le chromosome de la cellule réceptrice, en passant par l'initiation du transfert au niveau de l'origine de transfert et le transfert au travers du pore de conjugaison synthétisé par l'ICE. La diversité génétique de la famille des MGI a également été étudiée et apporte des précisions sur leurs rôles et leur possible origine évolutive.
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15

Hu, Xiaopei. "Application of Alternative Technologies to Eliminate Vibrios spp. in Raw Oysters." Diss., Virginia Tech, 2004. http://hdl.handle.net/10919/25940.

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High pressure processing (HPP) and gamma irradiation were applied to inactivate Vibrio vulnificus (MO624) and Vibrio parahaemolyticus (O3:K6 TX2103) in pure culture and in inoculated live oysters. Vibrio pure culture and inoculated oysters were exposed to pressures of 207 MPa (30 kpsi) to 552 MPa (80 kpsi) for 0 min to maximum of 20 min. More than 5.4 log reductions of V. vulnificus occurred at 345 MPa for 0 min in oysters; 345 MPa for 2 min can achieve 4 log reductions on V. parahaemolyticus. Dosage of 1 kGy gamma-irradiation was proved to be effective in producing Vibrio free oysters with comparable organoleptic quality to raw oysters. Thermal conductivity of shucked oysters was measured to be 0.58 to 0.68 W/m°C, as temperature increased from 0 to 50 °C, using a line heat source probe. The specific heat was measured by differential scanning calorimeter methods. It increased from 3.80 to 4.05 kJ/kg °C, when temperature rose from 10 to 50 °C. The thermal diffusivity was calculated employing the data of thermal conductivity, specific heat and density of shucked oysters. The results showed that, under the tested temperature range, thermal properties did not change significantly with temperature. The dielectric constant and loss factor of oysters were determined by an open-ended coaxial line probe connected to a network analyzer at frequency of 30 MHz to 3000 MHz from 1 to 55 °C. The penetration depth of dielectric heating was calculated to be 1.1 cm with the dielectric constant of 55 and loss factor of 14. A two-dimensional mathematical model was established to simulate the heat transfer of microwave heating using a fish gel. Finite difference method was utilized to solve partial differential heat transfer equations. The model was able to predict the temperature distribution in heated fish gel with an accuracy of ± 8°C. Applying the developed mathematical model, the lethality of Vibrio spp., artificially inoculated in live oysters, was estimated collectively by integrating the individual localized lethality of designated heating units. The predicted lethality was compared with microwave enumeration data on Vibrios in oysters. The observed maximum log reductions by microbial enumeration were 4.4 and 3.4 for V. vulnificus and V. parahaemolyticus, respectively. The lethality calculated by integrating temperature profiles was acceptable. The discrepancy between the estimated lethality and microbial test was attributed to the simplified model construction. The quality of processed oysters, including color, aroma and texture properties, was evaluated instrumentally by a digital image system, an electronic nose and universal testing machine. The performance of two electronic nose systems on their abilities to detect oyster aroma and classify the aroma data into distinct groups was evaluated using a trained sensory panel and microbial tests. Cyranose 320 system has demonstrated potential as a quality assessment tool due to its sound correlation with microbial quality data and sensory evaluation scores. According to the quality measurement results, high pressure processing conditions were recommended to be at 345 MPa for less than 3 min and 379 MPa for less than 1.5 min. Deterioration of the quality was distinct for oyster meats exposed to 60 °C or above by thermal processing. The critical thermal processing condition was identified to be 55 °C for 2 min. With careful control, microwave processing could be considered as a candidate for seafood processing to reduce potential bacterial hazard but still retain the quality of the product.
Ph. D.
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16

James, Adèle. "Ecology, evolution and virulence of environmental vibrios." Electronic Thesis or Diss., Sorbonne université, 2018. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2018SORUS477.pdf.

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Les changements globaux provoquent une augmentation des infections associées aux Vibrio. Les vibrioses affectent les humains, mais aussi des animaux marins. Un problème majeur est le manque de connaissances sur les vibrios présents dans l’environnement. Pour mieux comprendre et gérer ces maladies, nous nous sommes intéressés à l’écologie, l’évolution et la virulence de ces agents infectieux. Tout d’abord, nous avons montré que dans la nature, certains génotypes de Vibrio sont virulents pour les huîtres et que leurs mécanismes de virulence sont impliqués dans la différentiation écologique de ces souches. En France, les parcs ostréicoles font face à des évènements de mortalités massives associés à la présence d’un virus et de bactéries du genre Vibrio. Nous avons montré que le virus n’est ni essentiel, ni suffisant pour induire de fortes mortalités, contrairement aux vibrios qui jouent un rôle majeur. Les huîtres juvéniles malades sont toujours infectées par plusieurs populations, mais une seule, Vibrio crassostreae, est détectée en abondance. La virulence de cette population dépend d’un système de sécrétion de type IV codé par un plasmide conjugatif. Nos résultats suggèrent que V. crassostreae était un colonisateur peu virulent et que l’invasion du plasmide l’a rendu hautement pathogène. La distribution restreinte du plasmide de virulence suggère qu’il a été sélectionné par les hautes densités d’élevages. Enfin, nous avons montré que le transfert ou la sélection du plasmide était favorisé dans l’huître, suggérant que l’huître représente une niche propice aux transfert latéraux de gènes. Ce travail pourra permettre le développement d’outils de diagnostic et le suivi épidémiologique des vibrios pathogènes
Global change, including anthropogenic activities, have resulted in an increase in the incidence of Vibrio-associated illnesses. These diseases not only affect humans but also marine animals. Despite strong ecological and economic consequences, little is known about population structure and virulence mechanisms of vibrios in the environment. To better understand and manage those diseases, we explored the ecology, the evolution and the virulence of these infectious agents. First, we found that some environmental strains were virulent towards oyster and we identified original virulence mechanisms related to their ecology and evolution. In France, oyster-farms are facing massive mortality events associated with the presence of a virus and bacteria of the genus Vibrio. We showed that the virus appears neither essential nor sufficient to cause high mortality rates contrary to the vibrios that play a major role. Juvenile diseased oysters were always co-infected by several populations, but only one, Vibrio crassostreae, was detected systematically and in abundance. Its virulence is dependent on a type VI secretion system that is carried by a conjugative plasmid. Our results suggest that V. crassostreae first differentiated into a low-virulent oyster colonizer and turned into a pathogen after acquisition of the virulence plasmid. The narrow distribution of the plasmid suggests that it has been selected by high density farming areas. Finally, we showed that the plasmid transfer or selection was enhanced in oysters, which suggests that oysters represent a niche for horizontal gene transfer. Overall, this work can lead to the development of diagnostic tools and epidemiological monitoring of pathogenic vibrios
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Bienlien, Lydia M. "Influence of Perkinsus Marinus Infection and Oyster Health on Levels of Human-Pathogenic Vibrios in Oysters." W&M ScholarWorks, 2016. https://scholarworks.wm.edu/etd/1477068161.

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The eastern oyster Crassostrea virginica is an ecologically and commercially important species whose natural populations have been devastated by overharvesting, habitat destruction, and disease, but the rapid growth of oyster aquaculture has shown potential to restore the economic significance of this species. A key threat to the growth and sustainability of oyster aquaculture is the association of human-pathogenic Vibrio bacteria with product marketed for raw consumption. Two Vibrio species, Vibrio vulnificus and Vibrio parahaemolyticus, are the causes of the highest rates of seafood consumption-related mortality and gastrointestinal illness, respectively. Identification of the factors influencing V. vulnificus and V. parahaemolyticus prevalence and intensity in oysters is fundamental to better risk management. Within the oyster, these bacterial species interact with the same tissues as the prevalent oyster parasite, Perkinsus marinus, yet little is known about the effect of P. marinus infection on bacterial levels. Answering the fundamental question of whether P. marinus correlates with V. vulnificus and V. parahaemolyticus levels in oysters was the focus of this research. Oysters were deployed in the York River, Gloucester Point, VA, where both Vibrio species and P. marinus are endemic, and were sampled at five time points when levels of both P. marinus and Vibrio spp. were expected to be high in oysters. Abundance of all three organisms and pathogenic strains of V. parahaemolyticus were determined in individual oysters using molecular methods to investigate potential correlations between parasite and bacterial abundance. Additionally, the levels of V. vulnificus and V. parahaemolyticus in relation to histopathology associated with P. marinus infection and other conditions were determined. The following year, manipulation of P. marinus disease progression, which is slowed by lower salinities and favored by higher salinities, was attempted by deploying oysters at two additional sites of different salinities to gain insight into whether the timing of P. marinus infection emergence directly influences Vibrio levels. No correlation was observed between total abundance of P. marinus and either V. vulnificus or V. parahaemolyticus. Manipulation of P. marinus disease progression produced no effect on P. marinus emergence, so this yielded no insight into P. marinus-Vibrio interactions. Histopathological analyses did not reveal any correlations between P. marinus ranking, distribution, or associated tissue damage and Vibrio spp. levels. Though few in number, oysters infected by Haplosporidium nelsoni were characterized by higher levels of V. vulnificus, and oysters of peak gametogenic development had significantly higher levels of pathogenic strains of V. parahaemolyticus. The results with regard to H. nelsoni and gametogenic state warrant further study. The primary conclusion of this study is that oyster health has little influence on levels of human-pathogenic Vibrio species in oysters, inter-host variability in Vibrio levels is likely explained by other factors.
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Rubio, Tristan. "Diversité des mécanismes d’interactions des vibrios du clade Splendidus et de leur hôte, l'huître creuse Crassostrea gigas." Thesis, Montpellier, 2017. http://www.theses.fr/2017MONTT098/document.

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Au sein du clade Splendidus, Vibrio tasmaniensis et Vibrio crassostreae sont deux populations de vibrios virulentes pour l’huître qui ont été associées au syndrome de mortalité des huîtres juvéniles. Nous nous sommes intéressés à la diversité des mécanismes d'interaction entre ces vibrios et leur hôte, l'huître creuse Crassostrea gigas. Dans un premier temps, nous avons précisé le processus de pathogénèse de la souche V. tasmaniensis LGP32 et montré qu’elle possédait une activité cytotoxique sur les cellules immunitaires de l’huître, les hémocytes, qui dépendait de sa phagocytose. Le transcriptome intracellulaire de LGP32 a révélé le rôle important des systèmes antioxydants et de l’efflux du cuivre dans la survie du vibrio à l’intérieur du phagosome. D’un point de vue fonctionnel, nous avons montré que ces mécanismes jouaient un rôle important au cours de la pathogénèse in vivo. Dans un second temps, nous avons réalisé une étude comparative des interactions entre des souches représentatives des deux populations V. tasmaniensis et V. crassostreae et l’huître. Nous avons montré que les souches virulentes des deux populations étaient cytotoxiques pour les hémocytes mais que cette cytotoxicité était indépendante de la phagocytose chez les V. crassostreae, à l’inverse des V. tasmaniensis. Le transcriptome des huîtres a montré que les souches virulentes des deux populations réprimaient l’expression de gènes impliqués dans la réponse antibactérienne. Des réponses spécifiques à chaque souche virulente ont également été identifiées, révélant la diversité des interactions. In vivo, les souches virulentes se sont montrées capables de coloniser les tissus de l'huitre, contrairement aux souches non virulentes contrôlées par les hémocytes. L’ensemble de nos travaux montre que, bien qu’il existe un degré de diversité et de spécificité des interactions entre différents vibrios du clade Splendidus et l’huître, les deux populations virulentes sont cytotoxiques pour les cellules immunitaires, et ce processus est essentiel pour leur succès infectieux. Ainsi, la capacité de dépasser les défenses hémocytaires est un phénotype conservé entre les populations virulentes du clade Splendidus. Les processus évolutifs ayant conduits à l’émergence de ces traits de virulence communs entre populations de vibrios pathogènes différentes méritent d’être explorer
In the Splendidus clade, Vibrio tasmaniensis and Vibrio crassostreae are two populations of virulent vibrio for oysters that are associated to "juvenile oyster mortality syndrome". Here we were interested in the diversity of interaction mechanisms between the vibrios and their host, the oyster Crassostrea gigas. First, we investigated the pathogenesis process of the strain V. tasmaniensis LGP32 and showed that it exerts a cytotoxic activity against oyster immune cells, the hemocytes, which depend on its entry into the cells through phagocytosis. Transcriptomic analysis of LGP32 response during intracellular stage revealed a crucial role for antioxydant systems and copper efflux in intraphagosomal survival of the bacteria. From a functional point of view, we showed that this virulence mechanisms of LPG32 play a major role in pathogenesis in vivo. Second, we realized a comparative study of the interaction mechanisms between representative strains of the two populations V. tasmaniensis and V. crassostreae with the oyster. Virulent strains from both populations were cytotoxic for hemocytes but this cytotoxicity was independant of phagocytosis in the case of V. crassostreae, in contrary to V. tasmaniensis. Transcriptomic analysis of the oyster responses during infection showed that virulent strains of both populations repressed the expression of genes involved in antibacterial responses. However, some pecific responses were also identified for each virulent strain, highlighting some diversity of interactions. In vivo, virulent strains were able to colonize oyster tissues, in contrary to non-virulent strains, which were controlled by hemocytes. Our work show, although a certain degree of diversity and specificity exist in the interactions between different vibrios of the Splendidus clade and oysters, both virulent populations are cytotoxic for immune cells, and this process is essential for their infectious success. Thus, the capacity to overcome the hemocyte defenses is a conserved phenotype between distinct virulent populations of vibrios from the Splendidus clade. Hence, it would be of particular interest to determine the evolutionary processes that drove the emergence of common virulence traits in distinct populations of pathogens
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Romero, Ormazábal Jaime. "Microflora en ostras chilenas y su incidencia en la colonización por vibrios patógenos y en la descomposición post cosecha." Tesis, Universidad de Chile, 2002. http://www.repositorio.uchile.cl/handle/2250/106698.

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20

Lavezzo, Lígia Carolina. "Caracterização das especies de vibrios isoladas em amostras de água do mar, plâncton e bivalves da zona litorânea do Estado de São Paulo." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/87/87131/tde-18112015-192329/.

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Neste estudo, objetivou-se caracterizar ao nível molecular os vibrios isolados de amostras de água do mar, plâncton e bivalves do Canal de São Sebastião (n=78), Baixada Santista (n=37) e Ubatuba (n=17), analisar a susceptibilidade aos antibióticos e os principais genes associados à virulência. Observou-se sensibilidade à ciprofloxaxina, meropenem e ácido nalidíxico, resistência à ampicilina e à cefalotina, e alta porcentagem de múltipla resistência (Ubatuba: 64,7%; Baixada Santista:48,6%; Canal de São Sebastião: 43%) aos antimicrobianos. Quatro isolados foram positivos para o gene de virulência stn/sto. Por MLSA, foi possível identificar V.alginolyticus, V.fluvialis, V.campbellii e V.harveyi em Ubatuba; V.fluvialis, V.alginolyticus, V.campbellii, V.rotiferianus, V.harveyi, V.diabolicus, V.atypicus, V.coralliilyticus, V.maritimus, V.parahaemolyticus e V.tubiashii no Canal de São Sebastião; e, V.alginolyticus, V.parahaemolyticus, V.rotiferianus, V.campbellii, V.harveyi, V.communis, V.maritimus, V.fluvialis, V.fortis, V.natriegens e V.navarrensis na Baixada Santista.
The aim of this study was to characterize at the molecular level Vibrio species isolated from seawater, plankton, bivalves samples from Canal de São Sebastião (n=78), Baixada Santista (n=37) and Ubatuba (n=17), to analyze antimicrobial susceptibility and the major virulence-associated genes. The results showed ciprofloxacin, meropenem, nalidixic acid sensitivity, ampicillin, and cephalothin resistance, and a significant percentage of multidrug resistance (Ubatuba: 64.7%; Baixada Santista: 48.6%; Canal de São Sebastião: 43%). Four seawater isolates were found positive for the stn/sto virulence gene. MLSA allowed the identification of V.alginolyticus, V.fluvialis, V.campbellii, V.harveyi in Ubatuba; V.fluvialis, V.alginolyticus, V.campbellii, V.rotiferianus, V.harveyi, V.diabolicus, V.atypicus, V.coralliilyticus, V.maritimus, V.parahaemolyticus and V.tubiashii in Canal de São Sebastião, and V.alginolyticus, V.parahaemolyticus, V.rotiferianus, V.campbellii, V.harveyi, V.communis, V.maritimus, V.fluvialis, V.fortis, V.natriegens, and V.navarrensis in Baixada Santista.
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21

Badela, Andiswa Unathi. "Prevalence and pathogenicity of vibrios in treated final effluents of selected wastewater treatment plants in the Amathole District Municipality of Eastern Cape Province of South Africa." Thesis, University of Fort Hare, 2014. http://hdl.handle.net/10353/d1019774.

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Waterborne diarrhoeal infections continue to be a major health setback in developing countries, especially in rural areas which lack adequate supply of portable water and sanitation facilities. Globally, waterborne diarrhoeal infections occur with an estimated mortality rate of 10–25 million deaths per year, 95% of which are children under the age of 5 years. The Vibrio species is one of the major groups of enteric pathogens that are responsible for diarrhoeal infections. Many strains of these bacterial species continue to cause epidemics of diarrhoea throughout the world. In this study, the prevalence of Vibrio pathogens in wastewater final effluents was assessed. Wastewater final effluent and discharge point samples were collected monthly between September 2012 and August 2013. All samples were collected aseptically using sterile 1 L Nalgene bottles containing 0.5 ml of sterile sodium thiosulphate solution and transported on ice to the laboratory for analyses within 6 h of collection. The membrane filtration method was used for enumeration of presumptive Vibrio densities on thiosulfate citrate bile salt (TCBS) agar plates. Polymerase chain reaction (PCR) was then used to confirm the identities of the presumptive Vibrio species using the species-specific primers. The confirmed isolates were further subjected to molecular characterization to confirm their respective pathotypes. Presumptive Vibrio densities varied from 0 to 2.11 × 102 cfu/100 ml. Out of 300 confirmed Vibrio isolates; 13.3% (40/300) were Vibrio fluvialis, 22% (66/300) were confirmed to be Vibrio parahaemolyticus, and 24.7% (74/300) proved to be Vibrio vulnificus, and 40% (120/300) were other Vibrio species which were not assessed for in this study. The strains of Vibrio fluvialis were found to exhibit 100% resistance to Polymixin and Tetracycline. However, Gentamicin was active against all the three Vibrio species selected for the purpose of this research. The recovery of Vibrio species in the discharged effluents throughout the sampling period even in adequately disinfected effluents is not acceptable considering the fact that Vibrio is a pathogenic bacterium. The findings of this study underline the need for constant monitoring of the microbiological qualities of discharged effluents and might also be suggestive for a review of the disinfection methods used at the treatment works.
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22

Pretto, Tobia <1985&gt. "Vibriosi da Vibrio harveyi: studi di eziopatogenesi e di efficacia vaccinale nel branzino (Dicentrarchus labrax)." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amsdottorato.unibo.it/8699/1/pretto_tobia_tesi.pdf.

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Vibrio harveyi rappresenta un patogeno batterico emergente per l’acquacoltura marina a livello globale. Nel branzino V. harveyi è stato isolato in episodi di mortalità caratterizzati da atassia natatoria, lesioni cutanee ed enteriche. Un protocollo polifasico di identificazione per V. harveyi è stato standardizzato basandosi su metodi biochimici, molecolari e proteomici ed è stato valutato raffrontando una collezione di 81 isolati di campo di V. harveyi (specie ittiche e bivalvi) con ceppi di referenza di V. harveyi e di altre 22 specie della famiglia Vibrionaceae. La valutazione fenotipica si è basata su prove in macrometodo, micrometodo (API20E) e crescita su terreni TCBS e CHROMagar Vibrio. L’analisi molecolare ha impiegato il sequenziamento del gene housekeeping pyrH, e l’amplificazione specie-specifica del gene toxR. Il profilo proteico è stato determinato mediante MALDI-TOF analizzando il contenuto proteico ribosomiale. E’ stato valutato il profilo di sensibilità/resistenza agli antibiotici su 51 ceppi di V. harveyi, isolati da episodi clinici o da campioni ambientali, mediante metodo Kirby-Bauer e determinazione della minima concentrazione inibente (MIC). È stata indagata mediante infezioni sperimentali (immersione e inoculo intraperitoneale IP) la patogenicità di differenti isolati di V. harveyi in branzino valutando le lesioni anatomo-istopatologiche indotte. È stato inoltre sviluppato un protocollo vaccinale basato su vaccino spento polivalente da somministrare per immersione o per inoculo IP, addizionato con estratto extracellulare ed emulsionato o meno con adjuvante. Sono state condotte prove di sicurezza ed efficacia vaccinale determinando per i vari protocolli la percentuale relativa di sopravvivenza (RPS). Un metodo ELISA indiretto è stato sviluppato per comparare la risposta immunitaria (IgM sieriche) degli esemplari vaccinati con i differenti protocolli, evidenziando una risposta significativamente maggiore nei soggetti inoculati IP con vaccino adjuvato.
Vibrio harveyi is an emerging bacterial pathogen for marine aquaculture globally. In the European sea bass V. harveyi has been isolated in episodes of mortality characterized by ataxia, cutaneous and enteric lesions. In the present study, a polyphasic identification protocol for V. harveyi was standardized based on biochemical, molecular and proteomic methods and was evaluated by comparing a collection of 81 V. harveyi field isolates (fish and bivalve species) with V. harveyi reference strains and other 22 species of the family Vibrionaceae. The phenotypic evaluation was based on macromethod and micromethod (API20E) tests and growth on TCBS and CHROMagar Vibrio. Molecular analysis employed the sequencing of the housekeeping pyrH gene, and the species-specific amplification of the toxR gene. The protein profile was determined by MALDI-TOF analyzing the ribosomal protein content. The antibiotic susceptibility profile was evaluated on 51 V. harveyi strains, isolated from clinical episodes or environmental samples, applying the Kirby-Bauer method and determination of the minimum inhibitory concentration (MIC). The pathogenicity of different V. harveyi isolates in sea bass was investigated by experimental infections (immersion and intraperitoneal IP injection) and the induced anatomo-histopathological lesions were evaluated. A vaccine protocol based on a polyvalent bacterin was also developed to be administered by immersion or by IP, enriched with extracellular extract and emulsified or not with adjuvant. Safety tests and vaccine efficacy were carried out by determining the relative survival rate (RPS) for the various protocols. An indirect ELISA method was developed to compare the immune response (serum IgM) of the specimens vaccinated with the different protocols, highlighting a significantly greater response in the specimens inoculated IP with adjuvant vaccine.
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23

Piel, Damien. "Évolution de la virulence de V. crassostreae en lien avec l’huître en tant qu’hôte et les phages en tant que prédateurs." Electronic Thesis or Diss., Sorbonne université, 2019. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2019SORUS462.pdf.

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La compréhension de la dynamique écologique et évolutive des agents infectieux est importante pour diagnostiquer, prédire et prévenir les maladies chez les espèces d'élevage et sauvages. L'objectif général de ce projet est d'étudier l'évolution de la virulence de V. crassostreae en relation avec l'huître en tant qu'hôte et les phages en tant que prédateurs. Nous avons identifié des mécanismes moléculaires à l’origine de l’adaptation des vibrios avec l’huître creuse. Nous avons démontré l’émergence de souches virulentes de V. crassostreae en zone impactée par le syndrome de mortalité des huîtres juvéniles. L’émergence de V. crassostreae plus virulent est liée à l’acquisition d’un plasmide codant un système de sécrétion de type 6 responsable d’une activité létale contre les hémocytes de l’huître. Ce projet fournit également des connaissances sur les interactions entre V. crassostreae et les phages tels que l’identification de l’unité de prédation ainsi que de potentiels mécanismes impliqués dans la résistance des souches et la virulence des phages. Il s’agit d’une première étape vers le développement de stratégies prophylactiques ou thérapeutiques respectueuses de l’environnement
Understanding the ecological and evolutionary dynamics of infectious agents is important for diagnosing, predicting and preventing diseases in farmed and wild species. This project was aimed at studying the evolution of V. crassostreae virulence in relation to the oyster as a host and to the phages as predators. We identified the molecular mechanisms leading to the adaptation of vibrios to oysters. We demonstrated the emergence of virulent strains of V. crassostreae in the area impacted by the juvenile oyster mortality syndrome. The emergence of more virulent V. crassostreae strains is linked to the acquisition of a plasmid encoding a type 6 secretion system responsible for lethal activity towards oyster hemocytes. This project also provides knowledge on the interactions between V. crassostreae and phages such as the identification of the predation unit as well as potential mechanisms involved in strain resistance and phage virulence. This represents a first step towards the development of prophylactic ecofriendly strategies
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24

Zhao, Weining [Verfasser], Stephan [Akademischer Betreuer] [Gutachter] Sieber, and Tobias [Gutachter] Gulder. "Investigation of Fimbrolide and Beta-Lactone Targets Related to the Inhibition of Quorum Sensing-Regulated Bioluminescence in Vibrios / Weining Zhao ; Gutachter: Tobias Gulder, Stephan Sieber ; Betreuer: Stephan Sieber." München : Universitätsbibliothek der TU München, 2016. http://d-nb.info/1117796701/34.

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25

Melo, Ligia Maria Rodrigues de. "Resistotipagem e transfer?ncia gen?tica de plasm?dios de resist?ncia entre coliformes e vibrios potencialmente patog?nicos para o homem isolados de camar?o (litopenaeus vannamei) comercializado em Natal-Rio Grande do Norte." Universidade Federal do Rio Grande do Norte, 2012. http://repositorio.ufrn.br:8080/jspui/handle/123456789/13261.

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Made available in DSpace on 2014-12-17T14:13:43Z (GMT). No. of bitstreams: 1 LigiaMRM_TESE.pdf: 4862678 bytes, checksum: 4e18ee0ba221a5515a64d23067db9388 (MD5) Previous issue date: 2012-02-28
Cinquenta amostras de camar?o fresco e refrigerado (Litopenaeus vannamei) foram coletadas em diferentes pontos de comercializa??o na cidade de Natal RN. As amostras foram maceradas em um gral est?ril e 25 gramas semeadas em 225mL de APA contendo 1% de NaCl e 25g em 225mL de CL incubadas a 35?C - 24 horas. O crescimento em APA foi semeado em placas de ?gar TCBS, incubadas a 35?C-24h para isolamento de Vibrio e Aeromonas. O crescimento do CL foi semeado em Agar EAM, para isolamento de coliformes. Dos 102 isolados, 91 (89,2%) pertenciam ao g?nero Vibrio e 11 (10,8%) ao g?nero Aeromonas, com predomin?ncia de V. cholerae n?o O1/n?o O139, V. alginolyticus, V. carchariae e V. parahaemolyticus K- e A. veronii biogrupo sobria , A. jandaei, A. schubertii, A. veronii biogrupo veronii e A. hydrophila. A menor efici?ncia entre os antimicrobianos foi da AMP (57,8% de resist?ncia) seguida da AMK (29,4%) e TCY (21,6%). As 39 cepas de Vibrio e Aeromonas multirresistentes se distribu?ram em 10 perfis distintos, sendo que um revelou cinco marcos (AMP, CHL, NIT, SXT e TCY) em um isolado de V. carchariae de camar?o, adquirido em supermercados. O ?ndice MAR, nas 39 cepas variou de 0,28 a 0,42, sugerindo que s?o de risco na transfer?ncia e difus?o da resist?ncia na cadeia alimentar. Ap?s a cura plasmidial pelo tratamento com AO de 24 cepas multirresistentes e com resist?ncia intermedi?ria de v?brio e aeromonas escolhidas aleatoriamente, 13 perderam totalmente a resist?ncia e 7 perderam parcialmente, sendo que o maior percentual de perda da resist?ncia ocorreu nas cepas de V. cholerae n?o O1 e n?o O139 (6 cepas), se concentrando nos marcos de resist?ncia a AMP (13), AMK (11), TCY(8) e CIP(3). Os resultados da conjuga??o realizada entre amostras de Vibrio xvi curadas e a E. coli K12C600 demonstraram que 78,5% das culturas de Vibrio testadas revelaram capacidade de transfer?ncia para o gene que confere resist?ncia a AMP e 28,5% para a TCY. Dos coliformes, E. coli foi a mais frequente, seguida de Citrobacter spp, isoladas em 40,3% e 27,5% das amostras respectivamente. AMP foi o antimicrobiano menos eficaz, seguido de TCY. As 11 cepas multirresistentes se distribu?ram em 9 perfis distintos, um deles constitu?do de cinco marcos (AMP, NIT, TCY, CHL, SXT), albergados em uma cepa de Klebsiella spp, oriunda de camar?o adquirido em supermercado, similar ao resultado obtido em V. carchariae. Conclui-se que, os camar?es marinhos frescos e refrigerados, comercializados em Natal-RN evidenciaram contamina??o com coliformes, v?brios e aeromonas multirresistentes a antimicrobianos comumente utilizados na terapia m?dica e veterin?ria, e que, possivelmente, a transfer?ncia de genes de resist?ncia entre bact?rias se constitui um s?rio problema de sa?de p?blica
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26

Travers, Marie-Agnès. "Interaction de la bactérie Vibrio harveyi avec son hôte, l’ormeau Haliotis tuberculata : approches physiologiques, cellulaires et moléculaires." Brest, 2008. http://www.theses.fr/2008BRES2007.

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Depuis quelques années seulement, l’aquaculture d’ormeau se développe en Europe, mais doit déjà faire face à de nombreuses maladies. Les populations naturelles, comme les élevages d’Haliotis tuberculatcz, ont subi de fortes pertes depuis les années 1997, principalement à cause d’une bactérie pathogène, Vibrio harveyi. La vibriose de l’ormeau européen, ses signes macroscopiques, ainsi que les conditions favorables à son développement ont été étudiés par des suivis in situ et des expériences en laboratoire. Ces études nous ont permis de démontrer l’importance de la température (>17°C), de la physiologie des animaux (période de reproduction) et de la présence d’une souche pathogène (porteuse du plasmide pVCR1) pour le développement de la vibriose. Un cycle de la maladie et une première localisation des tissus cibles des ormeaux (branchies, muscle et hémolymphe) ont été proposés. De plus, un lien clair entre la période de reproduction avec un déficit immunitaire et la sensibilité des animaux a également été établi. Par des approches moléculaires, il a été démontré que les souches virulentes de V. Harveyi interfèrent avec le système immunitaire probablement via une inhibition partielle de la voie d’activation des MAP Kinases dans les hémocytes. Enfin, nous avons pu mettre en évidence le rôle clé des plasmides pVCR dans la virulence des souches
Abalone aquaculture has only recently been developed in western Europe, and already it has had to face numerous pathologies. Since 1998, natural and farm stocks of Haliotis tuberculata have suffered high mortalities on a regular basis, mainly due to the pathogenic bacterium, Vibrio harveyi. The vibriosis ofthe European abalone, in particular its macroscopic signs, and the conditions necessary for its development have been studied in detail by field and laboratory experiments. We have been able to show the importance of the interplay between water temperature (>17°C), animaI physiology (reproduction period) and a pathogenic strain (harbouring the plasmid pVCR1) for the development of this abalone disease. A limited localisation study of the abalone target tissues (gills, muscle and haemolymph) has been performed and a 3 phase disease development model is hypothesized. A clear link between the reproduction period with its accompanying immune difficiency and the animals sensitivy to the pathogen has been established. Using a molecular, approach strains of virulent V. Harveyi were found to directly intervene with the animal’s immune system, probably through a partial inhibition of the MAP kinase pathway activation in the haemocyte. Finally, we were also able to show the utmost importance ofthe pVCR plasmids for the virulence phenotype of this pathogenic bacterium
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Cardinaud, Marion. "Étude multifactorielle de la vibriose chez l'ormeau européen Haliotis tuberculata : bases génomiques et physiologiques de la survie aux mortalités estivales chez l'ormeau européen Haliotis tuberculata." Thesis, Brest, 2013. http://www.theses.fr/2013BRES0062/document.

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Depuis une quinzaine d’années, des mortalités estivales d’ormeaux européens, Haliotis tuberculata, surviennent sur le littoral breton et normand, et en structures aquacoles. Ces mortalités sont attribuées à l’espèce bactérienne Vibrio harveyi, et se produisent chez des ormeaux sexuellement matures lorsque la température de l’eau dépasse 17°C.Ce travail de thèse visait en une approche multifactorielle de l’étude de cette interaction hôte-parasite, afin de spécifier les conditions intrinsèques aux ormeaux dans le déclenchement de cette vibriose, le cycle infectieux de V. harveyi chez l’ormeau européen et le rôle de la température dans l’accomplissement de ce cycle infectieux, et enfin la réponse physiologique de l’ormeau lors d’une exposition à V. harveyi.Les principaux résultats montrent un différentiel d’expression génomique entre des ormeaux résistants et des ormeaux sensibles au cours d’une exposition à V. harveyi, attestant ainsi l’importance du statut physiologique de l’hôte dans la survie à la vibriose chez l’ormeau européen. Ce constat est supplémenté de la mise en évidence de sensibilité à cette maladie chez des ormeaux sexuellement immatures, habituellement résistants, acclimatés à 19°C et exposés à des conditions contraignantes de type manipulation. Par ailleurs, l’étude de la voie d’entrée et de la dynamique d’infection de V. harveyi chez l’ormeau européen a révélé un tropisme particulier de ce vibrion pathogène vers les tissus branchiaux dès les premières heures de contact, et son invasion dans le système circulatoire dès 24h de contact. L’étude de la réponse hémocytaire des ormeaux et du métabolisme branchial, à l’échelle moléculaire et cellulaire, lors des premières heures de contact, démontre 1/ la genèse d’un stress oxydatif au niveau des branchies d’ormeaux sensibles à la vibriose et 2/ une altération du fonctionnement des hémocytes, ce qui présume de l’une des stratégies majeures de virulence de V. harveyi
For fifteen years, summer mortalities have been observed in wild and farmed populations of European abalone, Haliotis tuberculata, along the north French coast. These mortalities are attributed to the bacterial species Vibrio harveyi and occur in sexually mature animals, when the seawater temperature exceeds 17°C.A multifactorial approach to the study of this host-parasite interaction was done during this thesis, in order to specify the intrinsic abalone conditions in vibriosis mortalities, the infectious cycle of V. harveyi in European abalone and the role of temperature in the fulfillment of this infectious cycle, and finally the physiological response of abalone, at cellular and molecular level, when exposed to V. harveyi.The main results showed a differential gene expression between resistant and susceptible abalone during exposure to V. harveyi, indicating the importance of the physiological status of the host, in survival to vibriosis. This hypothesis is supplemented by the susceptibility of sexually immature abalone at 19°C to this disease, usually resistant, and exposed to manipulation stressor. Moreover, the study of the portal of entry and the dynamics of infection by V. harveyi in European abalone revealed a particular tropism of this vibrio pathogen for gill tissues, in the earlier hours of contact, and its invasion into the circulatory system from the first 24 hours of contact. The study of the response of abalone hemocyte and gill metabolism, at the cellular and molecular level, in the earlier hours of contact, shows 1/ a genesis of oxidative stress in gills of susceptible abalone, and 2/ an alteration of hemocyte functions, which may constitute one of the major strategies of virulence in V. harveyi
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Midonet, Caroline. "Mécanisme d'intégration du phage TLC dans le génome de Vibrio cholerae." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS314/document.

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La plupart des bactéries ont un unique chromosome circulaire. Lors de la réplication de l’ADN, la circularité lie topologiquement les deux chromatides sœurs résultant de la réplication (caténanes et dimères). Ces liens topologiques doivent être résolus afin de permettre une bonne ségrégation de l’information génétique entre les deux cellules filles au cours de la division cellulaire. Les bactéries possèdent une machinerie très conservée: les recombinases à tyrosines XerC et XerD, capables de résoudre les dimères et une partie des caténanes, en catalysant un crossover au site spécifique dif situé dans la région Ter du chromosome. Lors de ce processus elles réalisent successivement deux échanges de brins. La réaction Xer est spatio-temporellement contrôlée par une protéine du divisome: FtsK. FtsK est une translocase qui pompe l’ADN à travers le septum de division. Lorsqu’elle rencontre une synapse constituée de deux sites dif chargés de XerC et XerD, elle active la catalyse de XerD pour initier le premier échange de brins. Dans un second temps XerC catalyse un second échange de brins indépendamment de FtsK. A ce jour le mécanisme d’activation de XerD n’est pas bien compris. Certains éléments mobiles résolvent leur états multimériques (tels que les plasmides) ou intègrent leur génome dans celui de leur hôte en détournant les recombinases XerCD. On parle d’IMEXs (integrative Mobile Element using Xer). Les éléments mobiles étudiés avant ma thèse utilisaient tous des voies de recombinaison initiées par la catalyse de XerC et ne nécessitant pas l’activation de XerD. Au cours de ma thèse j’ai étudié dans un premier temps le mécanisme d’intégration / excision d’une nouvelle classe d’IMEXs en utilisant comme modèle le phage TLCphi de Vibrio cholerae, la bactérie responsable du choléra. Par des approches de génétique j’ai démontré que TLCphi utilise une voie de recombinaison initiée par la catalyse de XerD et indépendante de FtsK. Mes travaux ont également montré que l’excision du phage participe à l’évolution des souches pandémiques de V.cholerae. Dans une seconde partie, j’ai identifié un facteur phagique qui permet à TLCphi de contourner le contrôle de FtsK sur l’activation de XerD. Ce facteur était une protéine de fonction inconnue présentant un domaine HTH et un domaine DUF3653. Ce dernier est retrouvé dans de nombreux IMEXs. Par des approches de biologie moléculaire j’ai étudié le mécanisme d’action de cette protéine. J’ai reproduit la réaction de recombinaison in vitro et démontré qu’elle active XerD en interagissant directement avec elle. Enfin dans un troisième temps, nous nous sommes intéressés aux disparités observées entre la recombinaison Xer chez E.coli et V.cholerae. En particulier, la recombinaison Xer semble agir seulement sur les dimères chez E.coli alors qu’elle est active également sur les monomères chez V.cholerae. Nous avons démontré que ces divergences de comportement ne viennent pas des Xer elles-mêmes, ni de leurs propriétés d'activations par FtsK. Elles résultent des différentes chorégraphies de ségrégation des chromosomes entre ces deux bactéries et dépendent également des vitesses de croissance
Most of bacteria have a single circular chromosome. During replication of DNA, this circularity can lead to two sister chromatids topologically linked (catenanes and dimers). These topological links have to be solved in order to allow good segregation of genetic information between the two daughter cells during cell division. Bacteria possess a highly conserved machinery: the tyrosine recombinases XerC XerD that are capable to resolve dimers and some catenanes, by catalyzing a crossover at the specific site dif located in the Ter region of the chromosome. During this process they realize two sequentialstrand exchanges.The Xer reaction is spatiotemporally controlled by a protein of the divisome: FtsK. FtsK is a pump that translocates DNA through the septum of division. When FtsK meets a synapse that consists of two dif loaded by XerC and XerD, it activates XerD catalysis that initiates first strand exchange. Secondly XerC catalyzes a second strand exchange independently of FtsK. To date the activation mechanism of XerD is not well understood. Some mobile elements solve their multimeric states (like plasmids) or integrate their genome into the chromosome of their host by using XerCD recombinases. Such integrative elements are named IMEXs (Integrative Mobile Element using Xer). The mobile elements studied before my thesis all used recombination pathways initiated by catalysis of XerC and not requiring activation of XerD .During my PhD I studied at first the integration mechanism / excision of a new class IMEXs using as a model the TLC phage Vibrio cholerae, the bacterium responsible for cholera. By genetic approaches I demonstrated that TLCphi uses a recombination pathway initiated by XerD catalysis and independently of FtsK. My work has also shown that the phage excision participates in the evolution of pandemic strains of V. cholerae. In the second part, I identified a phage factor that allows TLC to bypass the activation of XerD by FtsK. This factor was a protein of unknown function with a HTH domain and a DUF3653 domain. DUF3653 are found in many IMEXs. Using molecular biology approaches, I studied the mechanism of action of this protein. I reproduced the recombination reaction in vitro and demonstrated that this factor activates XerD by directly interacting with it. Finally, we were interested to study disparities between Xer recombination in E.coli and V.cholerae. In particular, the Xer recombination seems to act only on dimers in E.coli while it is also active on monomers in V.cholerae. We have demonstrated that these differences in behaviors do not come from Xer themselves or their activation by FtsK. They result from different choreographies of chromosome segregation between these two bacteria and are also dependent on growth rates
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29

DOURADO, Joanna. "Vibriose em camarões marinhos ( Litopenaeus vannamei, Boone 1931) cultivados no litoral de Pernambuco, Brasil." Universidade Federal Rural de Pernambuco, 2009. http://www.tede2.ufrpe.br:8080/tede2/handle/tede2/5686.

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Shrimp farming all over the world has been affected in the last years by many diseases, that have contributed to the development indexes decline in the production of farmed marine shrimp. On top of the losses due to diseases, it's important to mention that some of the vibrio species are zoonotic agents, meaning they can also cause diseases in humans. Given the importance of bacteria of the genus Vibrio to shrimp farming and public health, the aim of this study was to evaluate marine shrimp, correlate the clinical findings with the presence of the vibrio bacteria and identify the isolated species in the water of the ponds of cultivated marine shrimp in Pernambuco. The samples were collected from four coastal farms and the laboratory analysis consisted of the research and identification of the vibrio bacteria in the hepatopancreas and in the water of the tanks, and identification of any alteration by examination of fresh samples. Thiosulphate citrate bile salt agar (TCBS) was used as the culture media and the selected colonies were later biochemically tested. Four hundred and eighty shrimps were analyzed, of hose 424 (88.33%) showed to have vibrio and one or more alterations. There were identified a total of 903 alterations, the most frequent of muscle tissue (329; 36.43%) and the least frequent of the hepatopancreas tubules (121; 13.40%). When analizing the growth cycle, it was observed the largest number of alterations (503; 55.7%) in the dry season. Taking into account the weight of the shrimps, it was observed 540 (59.8%) alterations when the average weight was 8g. Out of all the analyzed animals, 314 (65.42%) showed to have vibrio, being 38 samples from the ponds water and 605 shrimp isolated. The most abundant species was V. mediterranei, (21.31%), considered an environmental species non pathogenic to shrimp, and the least abundant species were V. campbellii, V. rotiferanus, V. shiloni, V. splendidus, V. tapetis and V. wodanis (0.16 %). A dependency between the alterations found on the exam and the presence of the vibrio was noticed, showing that the aforementioned exam, combined to microbiological analyzes, is an important tool that should be used when monitoring the farms. It was also noticed a great variety of pathogenic and non pathogenic species of vibrio in the studied samples. Such microorganisms could, eventually, be related to shrimp and human infections, which could represent a risk for shrimp farming and public health respectively.
A carcinicultura mundial tem enfrentado nos últimos anos vários impactos causados por enfermidades, que contribuíram para a queda dos índices de desenvolvimento na produção de camarão marinho cultivado. Além das perdas causadas devido às enfermidades, ressalta-se que algumas espécies de víbrio são agentes zoonóticos, ou seja, podem causar doenças também em humanos. Dada a importância das bactérias do gênero Vibrio para a carcinicultura e saúde pública, objetivou-se avaliar camarões marinhos, associar os achados clínicos com a presença de bactérias do gênero Vibrio e identificar as espécies isoladas da água dos viveiros e de camarões marinhos (Litopenaeus vannamei) cultivados no litoral do estado de Pernambuco. As amostras foram coletadas em quatro carciniculturas do litoral e as análises laboratoriais compreenderam pesquisa e identificação de bactérias do gênero Víbrio no hepatopâncreas e na água dos viveiros, e identificação de alterações através do exame a fresco. Para o isolamento das espécies foi utilizado o meio de cultivo Ágar Tiossulfato Citrato Sais de Bile Sacarose (TCBS) e as colônias selecionadas foram posteriormente submetidas a provas bioquímicas. Foram analisados no total 480 camarões, destes 424 (88,33%) apresentaram um ou mais tipos de alteração. Foi identificado um total de 903 alterações, sendo a mais freqüente a da musculatura (329; 36,43%) e a menos freqüente a alteração dos túbulos do hepatopâncreas (121; 13,40%). Com relação ao ciclo de cultivo, foi observado o maior número de alterações (503; 55,7%) no período de estio. Levando-se em consideração a média de peso dos camarões verificou-se 540 (59,8%) alterações quando os mesmos estavam com peso médio de 8 g. Do total de animais analisados 314 (65,42%) apresentavam vibrio e uma ou mais alteração no exame a fresco. Foi obtido um total de 643 isolados de Vibrio, sendo 38 de amostras de água dos viveiros e 605 isolados de camarão. A espécie mais abundante foi V. mediterranei (21,31%), considerada espécie ambiental e não patogênica para o camarão, e as espécies de menor predominância foram V. campbellii, V. rotiferianus, V. shiloni, V. splendidus, V. tapetis e V. wodanis (0,16%). Foi verificada uma dependência entre as alterações encontradas no exame a fresco e a presença de vibrio, concluindo-se que o referido exame, associado à análise microbiológica é uma importante ferramenta que deve ser utilizada no monitoramento da saúde dos animais. Verificou-se também uma ampla variedade de espécies patogênicas e não patogênicas de víbrio nas amostras estudadas, que podem eventualmente estar relacionados a infecções nos camarões e nos humanos, representando um risco para a carcinicultura e para a saúde pública respectivamente.
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30

Navarro, Romain. "Etude structurale par RMN de la protéine TolAIII impliquée dans le mécanisme d'infection de Vibrio cholerae par le bactériophage CTXphi." Thesis, Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4079.

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Vibrio cholerae acquiert les gènes de la toxine cholérique suite à l’infection par le phage CTXphi et devient par la suite une bactérie pathogène. L'infection se déroule en deux étapes : une interaction entre le pilus TCP et le domaine pIIIN2ctx, puis la formation du complexe TolAIIIV.c/pIIIN1ctx. Cette seconde étape est l’étape limitante de l’infection. L’objectif général de ma thèse a été d’étudier les forces motrices associées à cette étape.1) J’ai étudié les mécanismes moléculaires associés à la spécificité phage/bactérie en ciblant les interactions électrostatiques et le feuillet intermoléculaire par RMN et double hybride bactérien.2) J’ai résolu la structure de TolAIIIV.c libre par RMN. La comparaison des structures de cette protéine à l’état libre et liée ont permis de mettre en évidence un changement conformationnel et de proposer un mécanisme moléculaire d’ajustement induit. De plus, l’étude de la flexibilité de la protéine par RMN à haute pression (HP) a montré l’importance de la cavité interne de la protéine TolAIII pour favoriser l’ajustement induit lors de la formation du complexe TolAIIIV.c/pIIIN1CTX.3) J’ai vérifié si l’ajustement induit observé précédemment était lié à la présence de cette cavité d’une manière générale chez les protéines TolAIII. Une étude de dispersion de relaxation et de RMN à HP de la protéine TolAIIIE.c a permis de vérifier l’importance de cette cavité pour le mécanisme d’ajustement induit essentiel à cette famille de protéine. De plus, nous avons corrélée la flexibilité particulière de la protéine TolAIIIE.c à la présence d’une boucle qui lui confère une certaines flexibilité nécessaires pour interagir avec plusieurs partenaires
Vibrio cholerae becomes a pathogen after CTXphi phage infection. The phagic infection is a wo step mechanism: first TCP pilus binds to pIIIN2ctx, then TolAIIIV.c binds to pIIIN1ctx. The second step is essential for the acquisition of genes of cholera toxins leading to cholera disease. The main goal of my thesis is to study the driving forces associated to the phage infection.First, I studied the molecular mechanism associated to phage/bacteria specificity targeting electrostatic bonds and hydrophobic interactions within the intermolecular sheet. These experiments use NMR and bacterial two hybrids methods. Our results show that electrostatic bonds are essential for the complex formation.Second, I solved the solution structure of TolAIIIV.c using NMR. The comparison of the structures of free and bound states of TolAIIIV.c, shows an associate conformational change and lead us to propose a model for the molecular mechanism of the induced fit. Then the study of the TolAIII flexibility, using high pressure NMR shows the importance of TolAIII cavity to promote the induced fit during TolAIIIV.c/pIIIN1ctx complex formation.Finally, we wanted to show if the induced fit is correlated to the presence of cavity in TolAIII family. A study using NMR relaxation dispersion and high-pressure NMR experiments on TolAIIIE.c shows the importance of this cavity for the induced fit. The presence of a loop at the top of the N-terminal helix in TolAIIIE.c leads to the protein to have several conformations necessary to interact with many partners
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Abi, Khalil Celina. "Effets apoptotiques du dinoflagellé Alexandrium catenella et de ses toxines sur les cellules immunitaires de l'huître creuse Crassostrea gigas : implications dans la susceptibilité de l'huître aux vibrioses." Thesis, Montpellier, 2016. http://www.theses.fr/2016MONTT108.

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En France, les sites ostréicoles de la méditerranée sont confrontés régulièrement à de fortes mortalités de juvéniles de Crassostrea gigas mais également à des efflorescences récurrentes du dinoflagellé producteur de toxines paralysantes (PSTs), Alexandrium catenella. Parmi les pathogènes associés de manière récurrente à ces mortalités, on retrouve des souches de Vibrio appartenant au clade Splendidus. Nous nous intéressons ici aux interactions entre A. catenella et l’huître C. gigas confrontée à des vibrios pathogènes. Dans une première partie, nous avons montré qu'en conditions expérimentales contrôlées, A. catenella augmentait la sensibilité de l’huître C. gigas au pathogène Vibrio tasmaniensis LGP32. In situ, nous avons également constaté la coïncidence entre la mortalité des huîtres en 2014 et la présence des PSTs dans leurs tissus. Dans une seconde partie, nous avons étudié les interactions entre les PSTs produites par A. catenella et les cellules immunitaires de l’huître, les hémocytes. Un résultat important de cette thèse a été de montrer que la saxitoxine, une des toxines produites par A. catenella, se lie à des structures granulaires présentes dans le cytoplasme des hémocytes de C. gigas et induit une mort hémocytaire caspases-dépendante. Cette mort est indépendante de la production d’espèces réactives de l’oxygène. Nous avons également démontré que la toxine majoritaire des cellules d’A. catenella, la gonyautoxine 5, est la plus toxique sur les hémocytes de C. gigas. Parmi les populations hémocytaires touchées, les hyalinocytes sont très sensibles à ce stress toxique. Les hémocytes étant les cellules immunocompétentes de l’huître qui jouent le rôle central dans la défense contre les infections, nous supposons que leur mort cellulaire induite par les PSTs affecte négativement la défense des mollusques bivalves et explique l'augmentation de la susceptibilité des huîtres à l'infection par Vibrio tasmaniensis LGP32 quand elles sont exposées à A. catenella
In France, oyster sites in the Mediterranean Sea are regularly confronted to high mortalities of Crassostrea gigas juveniles and to recurrent blooms of the dinoflagellate producer of Paralytic Shellfish Toxins (PSTs), Alexandrium catenella. Among the pathogens associated to these mortalities, we found Vibrio strains belonging to Splendidus clade. We here focus on the interactions between A. catenella and the oyster C. gigas challenged with pathogenic vibrios. In the first part of this work, we have shown that, in vivo, A. catenella increased the susceptibility of the oyster C. gigas to the pathogen Vibrio tasmaniensis LGP32. In situ, we also established the coincidence between oyster mortality in 2014 and the presence of PSTs in their tissues. In the second part of this work, we studied the interactions between the PSTs produced by A. catenella and oyster immune cells, the hemocytes. An important result of this thesis was that saxitoxin, a toxin produced by A. catenella, binds to granular structures in the cytoplasm of C. gigas hemocytes and induces their caspase-dependent cell death. This death is independent of the production of reactive oxygen species. We also demonstrated that the major toxin of A. catenella cells, the gonyautoxin 5, is the most toxic on C. gigas hemocytes. Among affected hemocyte populations, the hyalinocytes are very sensitive to this toxic stress. As hemocytes are oyster immunocompetent cells and therefore play the central role in the defense against infections, we can presume that their cell death induced by the PSTs negatively affects the defense of bivalve mollusks and explains the increased susceptibility of oysters to the infection by Vibrio tasmaniensis LGP32 when exposed to A. catenella
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32

Chow, Ka-hang. "Molecular characterization of RTX toxin of vibrio cholerae causing epidemics." Click to view the E-thesis via HKUTO, 2001. http://sunzi.lib.hku.hk/hkuto/record/B42575898.

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33

Naim, Sidrotun. "Growth, Vibriosis, and Streptococcosis Management in Shrimp-Tilapia Polyculture Systems, and the Role of Quorum Sensing Gene cqsS in Vibrio harveyi Virulence." Diss., The University of Arizona, 2012. http://hdl.handle.net/10150/268595.

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Tilapia culture in Indonesia was started with the Mozambique Tilapia (Oreochromis mossambicus) in the 1930’s, and the Nile Tilapia (Oreochromis niloticus) the 1960’s. The genetic improvement program of the Nile Tilapia, has led Indonesia to be one of the main tilapia producers in the world. On the other hand, shrimp aquaculture in the country was not started until the 1960’s, it became more popular after the eye ablation technology for broodstock maturation was developed in the early 1980’s. The first experimental study was conducted to investigate the feasibility of low salinity shrimp farming in a polyculture system with tilapia. Polyculture increased the survival for shrimp (77% compared to 62%), but at the same time decreased the survival of tilapia (87% compared to 97%). Together, the data on survival, specific growth rates, and feed conversion ratios showed that the shrimp performed well at low salinity. The second experimental study investigated the feasibility of brackishwater shrimp farming in a polyculture system with tilapia. Polyculture increased the survival for shrimp (82% compared to 65%), and had higher survival for the tilapia (60% compared to 43%). The Red hybrid Tilapia strain used in the study experienced mortalities after one month, suggesting the need for a salt tolerant strain. The presence of tilapia stimulated the growth of microalgae (Chlorella dominance), promoted higher numbers of heterotrophic bacteria in the water, and had lower presumptive vibrios on TCBS agar. A challenge study was conducted by mixing pathogenic luminescent Vibrio harveyi UAZ-651 into shrimp and tilapia feed. The survival of shrimp in monoculture were significantly lower (20%) compared to in polyculture systems (75 - 95%). Mortality was not found in tilapia. Based on 16S rRNA gene sequence, shrimp monoculture water was dominated by marine Vibrio spp., while the polyculture system had Bacillus spp. and Vibrio spp. with high homology to V. cholerae. The presence of Bacillus spp. which produce a lactonase enzyme AiiA, seems to inhibit vibrio growth. While providing advantages, shrimp-tilapia polyculture might also contribute to streptococcosis transmission. Injecting shrimp with Streptococcus iniae and S. agalactiae resulted in mortalities. S. iniae caused higher mortality in the shrimp cultured in 20 ppt (40%) compared to 10 ppt (20%), and no mortality in 5 ppt. S. agalactiae caused higher mortality in 5 ppt (40%) compared to 10 ppt (20%) and 20 ppt (20%). Quorum sensing (QS) is a density dependent cell to cell communication process in bacteria. Based on challenge studies in shrimp, the luminescent Vibrio harveyi BB120 wild-type strain caused 75-90 % mortality through injection of 106 CFU/shrimp. The mortality patterns in the QS mutants suggest that QS defined, when specific virulence genes were expressed or repressed. As QS in V. harveyi consists of three different circuits, further experiments deployed six mutants lacking either a synthase or a receptor for each circuit. The highest survival in the CqsS (a receptor for CAI-1 circuit) mutant group indicates that the CAI-1 circuit is the most crucial for virulence, followed by the AI-2 and HAI-1 cascades. Chitin acquisition and oxygen scavenging may be two reasons for luminescence in V. harveyi evolution and why they infect shrimp.
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34

Lambert, Christophe. "ETUDE DES INFECTIONS A VIBRIONACEAE CHEZ LES MOLLUSQUES BIVALVES, A PARTIR D'UN MODELE LARVES DE PECTEN MAXIMUS." Phd thesis, Université de Bretagne occidentale - Brest, 1998. http://tel.archives-ouvertes.fr/tel-00525764.

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Le contrôle des pathologies est un élément primordial pour réduire les risques en élevage larvaire de mollusques bivalves. Il requiert une connaissance précise des maladies, des pathogènes et de leur mode d'action. Une nouvelle espèce de vibrio pathogène pour les larves de P. maximus, Vibrio pectenicida a été décrite par des caractères phénotypiques et génotypiques. Elle appartient au groupe de V. splendidus dans lequel se retrouvent d'autres nouvelles espèces pathogènes. La pathogénie de V. pectenicida a été étudiée en histologie et par des infections expérimentales sur des élevages larvaires conventionnels et axéniques. Ces études ont confirmé le caractère pathogène des souches de V. pectenicida et l'absence de symptômes spécifiques de la maladie. En ultrastructure, la localisation des bactéries à l'intérieur des tissus et de cellules peut être expliquée par un phénomène de translocation. L'activité toxique des vibrios pathogènes se manifeste vraisemblablement par des facteurs internes à la bactérie. En effet, une action létale de lysats bactériens de Vibrionaceae, et principalement de la fraction cytoplasmique, a été mise en évidence sur des larves axéniques. L'existence de facteurs toxiques internes a été confirmée par l'utilisation d'un test de chimioluminescence (CL) sur des hémocytes d'adultes. En effet, l'activité inhibitrice observée avec les bactéries entières, a été retrouvée dans la fraction cytoplasmique des vibrios pathogènes. D'après des essais de purification partielle, un des facteurs toxiques doit être une petite molécule (moins de 3kDa), hydrophile, résistante aux protéases, aux acides et à la chaleur. Cette toxine est éloignée des toxines bactériennes déjà décrites. Les relations entre l'immunité des adultes, très résistants aux attaques bactériennes, et celles des larves ont été abordées à partir de deux expériences: une infection expérimentale provoquée par une souche proche de V. splendidus sur des P. maximus adultes et l'injection de V. pectenicida à des animaux adultes entraînant la baisse de réactivité des hémocytes. Enfin quelques applications pratiques ont été proposées pour éviter l'utilisation d'antibiotiques durant la phase larvaire.
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Croxatto, Antony. "VanT, a central regulator of quorum sensing signalling in Vibrio anguillarum." Doctoral thesis, Umeå : Umeå University, Department of Molecular Biology, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-702.

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Altinoglu, Ipek. "Organization of Bacterial Cell Pole." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS367/document.

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Chez les bactéries, les pôles cellulaires servent de domaines subcellulaires impliqués dans plusieurs processus cellulaires. Chez l’agent pathogène du choléra, Vibrio cholerae, en forme de bâtonnet incurvé, le pole contenant l’unique flagelle est impliqué dans la virulence. La protéine d’ancrage polaire HubP interagit avec plusieurs ATPases telles que ParA1 (ségrégation des chromosomes), ParC (localisation polaire du système de chimiotaxie) et FlhG (biosynthèse des flagelles), organisant ainsi l'identité polaire de V. cholerae. Cependant, les mécanismes moléculaires exacts de cet ancrage polaire doivent encore être élucidés. L’objectif de cette thèse est d’établir une vue d'ensemble de l'organisation de pôle cellulaire ce qui implique le mécanisme d’orchestration des différentes fonctions cellulaires par l’identification de l’ensemble des partenaires d'interaction de HubP ainsi que la cartographie fine du pôle cellulaire par microscopie à super résolution (PALM). Afin d’identifier de nouveaux partenaires d'interaction de HubP, j'ai étudié la différence de composition en protéines polaires entre les contextes HubP+ et HubP-. La composition en protéines polaires a été quantifiée de manière relative et absolue en ajoutant des Tag isobares aux protéines extraites de mini-cellules. Ces mini-cellules correspondent des petits compartiments cellulaires issus d’un évènement de division anormal proche du pole et sont enrichies en protéines polaires. Parmi ~800 protéines identifiées, ~ 80 protéines ont été considérées comme enrichies en contexte HubP+ incluant de nombreuses protéines attendues (FlhG, ParC et en aval des protéines de chimiotaxie). J'ai étudié la localisation de 14 protéines par microscopie à fluorescence et pu révéler 4 nouvelles protéines présentant une localisation polaire dépendant de HubP : VbrX, VbrY, et 2 protéines hypothétiques MotV et MotW. La délétion de motV et motW provoque un défaut significatif de propagation dans une gélose molle suggérant une implication dans la chimiotaxie et/ou la motilité. Alors que la microscopie électronique a montré que les deux mutants ont bien un flagelle polaire unique, le suivi-vidéo de leur déplacement a révélé que les deux mutants présentaient des défauts de nage assez distincts: ∆motV est plutôt affecté dans le changement de direction et ∆motW dans la vitesse de déplacement. Des expériences de microscopie fluorescente ont montré que MotV, MotW et HubP présentaient des dynamiques de localisation polaire distinctes au cours du cycle cellulaire. Pour une observation fine du pôle cellulaire par PALM, de nouveaux outils d’analyse d’image à haut débit étaient exigés. La précision des contours des petites cellules bactériennes faiblement contrastées n’est pas suffisante par l’observation en fond clair, j'ai développé une nouvelle technique de marquage avec des protéines fluorescentes photo-activables pour un tracé précis de la membrane interne ou du périplasme. En outre, nous avons créé un logiciel utilisant Matlab appelé Vibio qui intègre le contour de cellule et la liste des molécules obtenues par microscopie à super résolution. La capacité d’analyse à haut débit du logiciel permet d’étudier la distribution des molécules de l’échelle de la cellule unique à une population en orientant les cellules par leur courbure longitudinale. J’ai pu révéler que HubP est principalement localisé du côté convexe du pôle de la cellule, tandis que ses partenaires se situaient principalement au milieu du pôle. Mon travail de thèse a révélé avec succès de nouveaux partenaires d'interaction de HubP et la fonction de certaines protéines dans la motilité cellulaire. J'ai développé une nouvelle technique de microscopie pour une localisation subpolaire précise qui fonctionne bien pour l'analyse d'images PALM dans Vibio. J’ai ainsi pu faire progresser les connaissances de l’orchestration des fonctions polaires chez V. cholerae
In rod shaped bacteria, cell poles serve as important subcellular domains involved in several cellular processes including motility, chemotaxis, protein secretion, antibiotic resistance, and chromosome segregation. In the cholera pathogen Vibrio cholerae, vibrioid rod shape and single polarized flagellum involve in the virulence. Polar landmark protein HubP was shown to interact with multiple ATPases, such as ParA1 (chromosome segregation), ParC (polar localization of chemotaxis apparatus), and FlhG (flagella biosynthesis), thus organizing the polar identity of V. cholerae by tethering proteins to cell pole. However, the exact molecular mechanisms are yet to be elucidated. In this thesis, I tackled to unveil comprehensive view of the cell pole organization which implies the orchestration of different cellular functions, by identifying further interaction partners of HubP as well as drawing conceivable picture of the cell pole by super-resolution photoactivated localization microscopy. To identify new interaction partners of HubP, I used minicells in which cell poles were enriched as they derived from cell division near the cell pole. Difference in protein composition between HubP+ and HubP- minicells were examined by isobaric tags for relative and absolute quantitation. Among ~800 proteins identified, ~80 proteins were considered to be enriched in HubP+ minicells including many expected proteins (FlhG, ParC and downstream chemotaxis proteins). I chose 14 proteins to investigate their subcellular localization with fluorescent microscopy. In conclusion, I discovered 4 proteins that showed polar localization in a HubP-dependent manner. These proteins are VbrX, VbrY, and 2 hypothetical proteins MotV and MotW. ∆motV and ∆motW showed significant defect in a diameter of travel in soft agar plate that suggesting the possible involvement in chemotaxis and/or motility. Whereas electron microscopy showed that both mutants possess intact monotrichous flagellum, video-tracking revealed that the two mutants showed rather distinct defects during swimming: MotV is rather turning mutant while MotW is a speed mutant. Fluorescent microscopy experiments indicated that MotV, MotW and HubP showed distinct polar dynamics over cell cycle. For fine-scale observation of the cell pole by PALM, it was appreciated that novel tools for high-throughput analysis was demanded. Since brightfield images are not sufficient to have accurate contours of small and low contrast bacterial cells, I developed new labeling technique with photoactivatable fluorescent proteins for precise outlining at either inner membrane or periplasm. Furthermore, we created Matlab-based software called Vibio which integrates cell outline and the list of molecules obtained by super-resolution microscopy. High-throughput capability of the software enabled to analyze distribution of detected molecules from single cell to whole bunch of cells in a manner that cells are oriented by cell curvature. These allowed me to discover that HubP is mostly lopsided at the convex side of the cell pole, while its partners mostly located middle of the pole. Altogether, I successfully unveiled 4 novel interaction partners of HubP. I revealed of the function of hypothetical proteins that are involved in cell motility. I developed new labeling technique for precise polar localization that works well for PALM image analysis in Vibio. Therefore, I observed precise polar localization of HubP and other polar proteins
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37

Kural, Ayse G. "Temperature-assisted pressure inactivation of Vibrio parahaemolyticus and Vibrio vulnificus in oysters." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 89 p, 2007. http://proquest.umi.com/pqdweb?did=1338870531&sid=16&Fmt=2&clientId=8331&RQT=309&VName=PQD.

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38

Leung, Y. Tai Ida. "Infections à vibrio vulnificus, revue de la littérature à propos d'une observation de septicémie." Bordeaux 2, 1996. http://www.theses.fr/1996BOR2M053.

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39

Limthammahisorn, Suttinee Brady Yolanda Juanita Arias Covadonga R. "In vitro and in vivo cold shock response in Vibrio vulnificus." Auburn, Ala., 2007. http://repo.lib.auburn.edu/Send%2002-04-08/LIMTHAMMAHISORN_SUTTINEE_24.pdf.

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40

Alvarez, Julia D. "Studies on Venezuelan fish and shrimp associated bacteria." Thesis, Heriot-Watt University, 1998. http://hdl.handle.net/10399/619.

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41

Lima, Anahy de Souza. "VÃbrio em camarÃo e na Ãgua de trÃs fazendas de carcinicultura do CearÃ." Universidade Federal do CearÃ, 2007. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=2876.

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O presente estudo teve por objetivo quantificar Vibrio, vibrios sac+ e sac â e identificar as espÃcies de Vibrio, presentes no cultivo do camarÃo Litopenaeus vannamei e na Ãgua onde à ele cultivado. Acompanharamse dois ciclos do cultivo do L. vannamei em trÃs fazendas (A, B e C),situadas nos estuÃrios dos rios AcaraÃ, Coreaà e Jaguaribe (CE), de agosto de 2005 a outubro de 2006, nas estaÃÃes de chuva e estiagem. Foram analisadas 60 amostras de camarÃo e 240 amostras de Ãgua de viveiro. Foram feitos os testes de Contagem PadrÃo em Placas (CPP) total de Vibrio; CPP das colÃnias de Vibrio sacarose positivas e negativas, e identificaÃÃo das espÃcies nas amostras de camarÃo e na Ãgua. O valor mÃnimo da CPP de Vibrio nas amostras de Ãgua foi de 2,0 x 102 UFC/mL nas fazendas A, e C no perÃodo de chuva e o mÃximo foi 1,42 x 108 UFC/mL na fazenda B, no perÃodo de estio. O valor mÃximo para CPP de Vibrio nas amostras de camarÃo (pÃs-larva e hepatopÃncreas) foi de 4,5 x 108 UFC/g, na fazenda B no perÃodo de estio. O valor mÃnimo de Vibrio sacarose positiva no hepatopÃncreas foi 1,00 x 102 UFC/g nas fazendas A e B no perÃodo de chuva e mÃximo foi 4,5 x 108 UFC/g na fazenda B, no perÃodo de estio. O valor mÃnimo de Vibrio sacarose negativa foi 0,98 x 10 UFC/g de hepatopÃncreas na fazenda A, no perÃodo de chuva e mÃximo foi de 9,50 x 105 na fazenda C no perÃodo da chuva. A CPP de vibrios das amostras de Ãgua e do camarÃo foi sempre menor no perÃodo da chuva. Das amostras de Ãgua e camarÃo das trÃs fazendas foram isoladas 145 cepas de Vibrio. Dessas, 62 foram isoladas da Ãgua de cultivo do camarÃo e 56 foram isoladas do camarÃo (pÃs-larva e hepatopÃncreas). A fazenda B apresentou maior nÃmero de diferentes espÃcies isoladas e identificadas (11). Durante a esquisa, os isolados de camarÃo e Ãgua do viveiro, Apresentaram uma predominÃncia de Vibrio mimicus, seguidos de V.alginolyticus e V. tubiashii. De todas as fazendas, A, B e C, a fazenda Afoi a que apresentou um viveiro com a menor taxa de sobrevivÃncia de camarÃes na despesca: 37,24%, no perÃodo da chuva.Nem a quantidade de vÃbrios total, nem a de sacarose positiva, ou negativa no hepatopÃncreas dos camarÃes, influencia o Ãndice de SobrevivÃncia dos animais nos viveiros das fazendas, no momento da despesca. A maior ou menor diversidade de vÃbrios nos camarÃes nÃo implicou numa maior ou menor taxa de sobrevivÃncia dos animais nos viveiros das fazendas, no momento da despesca. No entanto, quando o nÃmero de Vibrio foi alto na Ãgua e a diversidade baixa, caso da Fazenda A no perÃodo da chuva, a taxa de sobrevivÃncia foi afetada negativamente. O nÃmero de vÃbrios à proporcional ao teor de salinidade das Ãguas. Somente os dados da enumeraÃÃo de vÃbrios e/ou os dados da enumeraÃÃo de vÃbrio sacarose positiva ou negativa nÃo sÃo suficientes para se avaliar a probabilidade de camarÃes, de um determinado viveiro, virem a adoecer.
This study aimed to quantify Vibrio, Vibrio and sac + sac - and identify the species of Vibrio, in the cultivation of shrimp Litopenaeus vannamei and water where it is grown. Acompanharamse two cycles of cultivation of L. vannamei in three farms (A, B and C), located in river estuaries AcaraÃ, and Coreaà Jaguaribe (EC), August 2005 to October 2006, at the stations of rain and drought. We analyzed 60 samples of shrimp and 240 samples of water from nursery. The tests were made in Standard Plate Count (CPP) of total Vibrio; CPP of colonies of Vibrio sucrose positive and negative, and identification of species in samples of shrimp and water. The minimum value of the CPP of Vibrio in the water samples was 2.0 x 102 CFU / mL in farms A and C in the period of rain and the maximum was 1.42 x 108 CFU / mL in farm B, in the period of summer . The maximum value for CPP of Vibrio in samples of shrimp (post-larva and hepatopÃncreas) was 4.5 x 108 CFU / g in farm B during the summer. The minimum value of sucrose positive Vibrio in hepatopÃncreas was 1.00 x 102 CFU / g in farms A and B in the period of rainfall and maximum was 4.5 x 108 CFU / g in farm B, in the period of summer. The minimum value of sucrose negative Vibrio was 0.98 x 10 CFU / g of hepatopÃncreas in farm A, the maximum period of rain and was 9.50 x 105 C on the farm during the rain. The CPP of Vibrio from water samples and the shrimp was always lower during the rain. Of water samples and the three shrimp farms were isolated 145 strains of Vibrio. Of these, 62 were isolated from the water culture of shrimp and 56 were isolated from shrimp (post-larva and hepatopÃncreas). The farm B showed the largest number of species isolated and identified (11). During esquisa, isolated from the shrimp and water in the nursery, showed a predominance of Vibrio mimicus, followed by V.alginolyticus and V. tubiashii. Of all the farms, A, B and C, Afoi farm that had a nursery with the lowest survival rate of shrimps in despesca: 37.24%, during the chuva.Nem the amount of Vibrio total nor the sucrose positive or negative in hepatopÃncreas of shrimp, influences the rate of survival of animals in the nursery of the farms at the despesca. The greater or lesser diversity of Vibrio in shrimp did not involve a greater or lesser rate of survival of animals in the nursery of the farms at the despesca. However, when the number of Vibrio in the water was high and low diversity, the case of Finance during the rain, the survival rate was affected negatively. The number of Vibrio is proportional to the level of salinity of water. Only data from the enumeration of Vibrio and / or data from the enumeration of Vibrio sucrose positive or negative is not sufficient to assess the likelihood of shrimp in a nursery, will sicken.
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42

Oliveira, Karina Zupo de. "Construção de filogenias baseadas em genomas completos." [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/275803.

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Orientador: João Meidanis
Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Computação
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Resumo: Contexto: A classificação de espécies começou sendo determinada pelas características fenotípicas dos organismos. Logo que o DNA foi descoberto, o sistema de classificação passou também a utilizar-se das características genotípicas. Ao longo dos últimos anos, avanços científicos permitiram que fossem sequenciados genomas completos. A cada ano, o número de genomas completamente sequenciados aumenta, e, com isso, é cada vez maior o número de trabalhos que tentam utilizar-se do maior número possível de genes para comparar dois ou mais organismos com o objetivo de melhor entender o relacionamento entre as diversas espécies. Experimento: Este trabalho executa comparações de pares de cromossomos de um grupo de 10 genomas completos da família Vibrionaceae e um genoma completo da bactéria Escherichia coli como externo ao grupo. As homologias entre as proteínas são determinadas através da base de famílias Protein Clusters (NCBI). A seguir, arvores ultramétricas e a classificação COG das proteínas são utilizadas para resolver as paralogias correspondentes. Após isto, as proteínas únicas, que representam os eventos de perda e ganho de genes, são eliminadas, de forma a igualar o conteúdo dos cromossomos. Tipicamente, 50% das proteínas originais do pares de organismos de mesma família 'sobrevivem" para serem utilizadas no cálculo da distância de rearranjo. Menos proteínas sobrevivem nas comparações com a bactéria externa ao grupo. A distância total é calculada pela soma do número de proteínas eliminadas e da distância de ordenação, medida através da distância de rearranjo dos cromossomos. Resultados: As comparações produziram matrizes de distâncias utilizadas para inferir árvores filogenéticas através do algoritmo Neighbor-Joining (NJ). As árvores filogenéticas encontradas mostraram-se congruentes em topologia com a árvore produzida pelo gene 16S rRNA. Isto mostra que a comparação de genomas completos é uma proposta sensata. Os desafios agora são aperfeiçoar os detalhes. O material suplementar (Apêndice A) contém uma implementação computacional dos experimentos
Abstract: Context: Species classification was originally determined by phenotypic characteristics. With the advent of DNA sequencing, the classification system started using genotypes as well. Over the last decades, scientific progress allowed complete sequencing of genomes. Each year, the number of genomes completely sequenced increases, and with it, the number of works trying to use as much genes as possible to compare two or more organisms, in order to get a better understand of the relationship between several species. Experiment: This work executes a pairwise chromosome comparison from a set of 10 complete genomes from the Vibrionaceae family and one complete Escherichia coli genome as an outgroup. In our experiment, the homologies between proteins are assessed using the Protein Clusters (NCBI) database. In the next step, paralogies are resolved using ultrametric trees and COG classification. In the sequel, the loss and gain events are treated, thus, proteins present in only one chromosome from the pair are eliminated, in order to equalize the set of families in both chromosomes. Typically, 50% of the original proteins survive in comparisons between organisms of the same family (comparisons with the outgroup yield less survivors). The total distance is calculated by adding the number of eliminated proteins with the order distance, which is measured by the rearrangement distance beetween the chromosomes. Results: Genome comparison produces distance matrices used to infer the phylogenetic trees through the Neighbor-Joining (NJ) algorithm. The phylogenetic trees generated are congruent regarding the topology with the tree inferred using the 16S rRNA gene. Also, in order to run a deeper investigation, the experiment was executed with some variations such as not resolving the paralogies using ultrametric trees or only classifying proteins using COG database. Supplemental material (Appendix A) contains the experiment computational implementation
Mestrado
Biologia Computaçional
Mestre em Ciência da Computação
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43

Mayer, Cintia Carolina da Silva. "Detecção molecular e resistência a antimicrobianos no grupo V. fluvialis - V. furnissii." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/6/6135/tde-28102010-144542/.

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Introdução - Vibrio fluvialis é um microorganismo que provoca a gastroenterite muito semelhante à cólera, mas também há relatos de casos extra-intestinais como sepse, ferida, peritonite e celulite hemorrágica e encefalite. Acredita-se que a infecção por esse microorganismo esteja vinculada ao consumo de peixes crus ou mal cozidos contaminados e / ou frutos do mar. A identificação dessa bactéria por métodos fenotípicos continua a ser um problema devido à sua grande semelhança com Aeromonas hydrophila e V.furnissii; por isso, a utilização de uma ferramenta de diferenciação entre essas espécies é importante. Nas últimas décadas, o aumento da resistência aos antimicrobianos tem sido um fator preocupante, porque ela interfere na escolha dos medicamentos para o tratamento eficaz e há uma necessidade de rápida produção de novos antibióticos. Ambientes costeiros e estuários estão em perigo de serem contaminados por esgoto, que pode conter drogas que agem de forma seletiva, permitindo o desenvolvimento de resistência aos antimicrobianos. Vários estudos demonstraram que estirpes clínicas de V. fluvialis são resistentes a múltiplas drogas. Objetivos - Desenvolver um marcador molecular baseado no 16S rDNA capaz de detectar o grupo V. fluvialis-V. furnissii, e avaliar a susceptibilidade a antibióticos destas espécies, principalmente a partir de amostras ambientais. Métodos - Após a elaboração dos iniciadores a partir do alinhamento das espécies do gênero Vibrio, foram utilizadas cepas identificadas fenotipicamente como V. fluvialis e de V. furnissii para a sua detecção molecular. O perfil de susceptibilidade a antibióticos pelo método da disco-difusão foi realizada, assim como a investigação molecular da presença do elemento SXT e de seus genes de resistência a antimicrobianos. Resultados: Com a utilização dos iniciadores desenvolvidos foi possível confirmar corretamente as espécies. Observou-se alta porcentagem de resistência a ampicilina e cefalotina, sendo que 65,9por centode V. fluviais e 43,24por centode V. furnissi apresentaram resistência a pelo menos dois dos antibióticos utilizados. Somente em uma cepa de V. fluvialis detectou-se a presença de SXT e houve uma banda desconhecida de alto peso molecular quando da pesquisa do gene sulII. Conclusões: O método molecular mostrou ser um importante instrumento para se detectar espécies altamente relacionadas. Foram detectadas cepas resistentes a múltiplos antibióticos, indicando que o meio ambiente é um provável reservatório de genes de resistência; porém necessita-se de futuras investigações moleculares para se determinar o papel destes e sua possível associação com elementos genéticos. A detecção do elemento SXT sem a presença dos seus genes de resistência conhecidos atualmente reforça a idéia da extensão de seu papel adaptativo, além de ser o primeiro relato de sua existência na América do Sul
Introduction - Vibrio fluvialis is a microorganism that causes gastroenteritis very similar to cholera, however there are also reports of extraintestinal cases as sepse, skin wounds, peritonitis and hemorrhagic cellulitis and cerebritis. It is believed that infection by this organism is linked to the consumption of raw or undercooked contaminated fish and / or seafood. Identification of this bacteria by phenotypic methods remains a problem due to its great similarity with Aeromonas hydrophila and V.furnissii, therefore the use of a tool to differentiate these species is important. In recent decades, increasing antimicrobial resistance has been a concerning factor because it interferes in the choice of drugs for effective treatment and there is a need for rapid production of new antibiotics. Coastal and estuarine environments are in danger of being contaminated by sewage, which may contain drugs that will act selectively, allowing the development of antimicrobial resistance. Several studies have demonstrated that clinical strains of V. fluvialis are resistant to multiple drugs. Objectives - To develop a 16S rDNA - molecular marker able to detect the group V. fluvialis-V.furnissii, and to evaluate the antibiotic susceptibility of this species mainly from environmental samples. Methods - After the development of primers from alignment of the genus Vibrio strains phenotypically identified as V. fluvialis and V. furnissii were used for their molecular identification. The profile of antibiotic susceptibility was performed by the disk diffusion method, and the molecular investigation of the presence of the SXT element and their antimicrobial resistance genes. Results - The primers developed were able to confirm correctly the species. A high percentage of resistance to ampicillin and cephalothin was observed, V. fluvialis and V. furnissii showed resistance to at least two of the antibiotics used, 65.9 per cent and 43.24 per cent respectively. Only in one strain of V. fluvialis we detected presence of SXT and there was an unknown band of high molecular weight when we investigated gene sulII. Conclusions - Molecular identification has proved to be an important tool for differentiating highly related species. Strains resistant to multiple antibiotics were detected, indicating that the environment is likely a reservoir for resistance genes, but it is needed further molecular investigations to determine their role and their possible association with genetic elements. Detection of the SXT element without the presence of its known resistance genes reinforces the idea of the extent of its adaptive role, and this is the first report of its existence in South America
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44

Guidolin, Angelo. "Molecular biology of "Vibrio cholerae" bacteriophage CP-T1 and its host interactions." Title page, contents and abstract only, 1985. http://web4.library.adelaide.edu.au/theses/09PH/09phg948.pdf.

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45

Hardman, Andrea M. "Quorum sensing in vibrio anguillarum." Thesis, University of Nottingham, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363936.

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46

Chalker, Victoria J. "Quorum sensing in Vibrio anguillarum." Thesis, University of Nottingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325714.

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47

Chow, Ka-hang, and 周嘉恆. "Molecular characterization of RTX toxin of vibrio cholerae causing epidemics." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B42575898.

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48

Carvalho, Edirsana Maria Ribeiro de. "Quantificação e identificação de Vibrio spp. na hemolinfa de camarões Litopenaeus vannamei cultivados em fazendas no Estado do Ceará." reponame:Repositório Institucional da UFC, 2009. http://www.repositorio.ufc.br/handle/riufc/18264.

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CARVALHO, Edirsana Maria Ribeiro de. Quantificação e identificação de Vibrio spp. na hemolinfa de camarões Litopenaeus vannamei cultivados em fazendas no Estado do Ceará. 2009. 89 f. : Dissertação (mestrado) - Universidade Federal do Ceará, Centro de Ciências Agrárias, Departamento de Engenharia de Pesca, Fortaleza-CE, 2009
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Most of shrimp bacterial infections are caused by Vibrio bacteria genus. This study aims to quantify identify Vibrio in the hemolymph of the marine shrimp Litopenaeus vannamei cultivated in farms in State of Cear, Brazil. Related is also the time of coagulation of hemolymph with counts of Vibrio. Sixteen samples were performed on four farms (A, B, C and D), eight shrimps with 4 g, and eight with eight grams shrimps. The collections were made in seasonal periods: rainy and drought. A total of 480 samples, and 240 to shrimps with 4 g and 8 g each, respectively. The values in the Standard Plate Count (SPC) of total vibrio, Vibrio Suc+ and Suc- in the hemolymph of shrimp samples with 4 g, in the rainy season ranged from: 2. 74 x 10⁴ to 28.70 x 10⁶ CFU/mL (est.), <6.0 to 14.64 x 106CFU/mL and <6.0 to 12.72 x 106 CFU/mL, respectively. For hemolymph of shrimp with 8 g of the SPC and the total Vibrio Suc+ and Sucranged from 1.68 x 10⁴ to 15.18 x 10⁶ CFU/mL (est.), <6.0 to 1.8 x 105 CFU/mL and <6.0 to 15.18 x 106CFU/mL (est). During the period of drought for these values of shrimp haemolymph of four grams, were: 9.0 x 10² (est.) to 5.40 x 104 CFU mL total Vibrio, <6.0 to 1.71 x 10⁴CFU/mL (Suc-) and <6.0 to 5.40 x 104 CFU/mL (Suc+). For shrimp with 8 g a total Vibrio count was 9.0 x 10² (est.) CFU/mL to 2.0 x 10⁷, <6.0 to 4.02 x 106 CFU/mL (Suc-) and <6.0 to 2.0 x 10⁷CFU/mL (est.) (Suc+). The results show that the rates of colonies of Vibrio Suc- and Suc+ were higher in the rainy season than in the drought. There was no relationship between the time of coagulation and the counts of Vibrio in the hemolymph of shrimps. The species that predominated in the period were: V. coralliilyticus, V. parahaemolyticus, Vibrio pelagius II, Vibrio alginolyticus, Vibrio mediterranei, Vibrio mimicus, Vibrio vulnificus B1
As infecções bacterianas em camarões são causadas, freqüentemente, por bactérias do gênero Vibrio O presente estudo teve por objetivo quantificar e identificar Vibrio na hemolinfa do camarão marinho Litopenaeus vannamei cultivado em fazendas no Estado do Ceará, Brasil. Relacionou-se também o tempo de coagulação das hemolinfas com as contagens de Vibrio. Foram realizadas 16 coletas em quatro fazendas (A, B, C e D), sendo oito para camarões com 4 g, e oito para camarões com oito gramas. As coletas foram realizadas nos períodos sazonais: chuvoso e estiagem. Perfazendo um total de 480 amostras, sendo 240 para camarões com 4 g e 8 g cada, respectivamente. Os valores da Contagem Padrão em Placas (CPP) de víbrios totais, de víbrios Sac+ e Sac-, nas amostras de hemolinfa dos camarões com 4g, no período chuvoso, variaram de: 2,74 x 104 a 28,70 x 106 UFC/mL (est.); de < 6,0 a 14,64 x 106UFC/mL e de < 6,0 a 12,72 x 106 UFC/mL, respectivamente. Para a hemolinfa dos camarões com 8 g os valores obtidos foram: 1,68 x 104 a 15,18 x 106 UFC/mL (est.), de < 6,0 a 1,8 x 105 UFC/mL e de < 6,0 a 15,18 x 106UFC/mL (est.), respectivamente. No período de estiagem esses valores para a hemolinfa dos camarões de quatro gramas, foram: 9,0 x 102 (est.) a 5,40 x 104 UFC/mL víbrio total; < 6,0 a 1,71 x 10⁴UFC/mL (Sac–) e de < 6,0 a 5,40 x 104 UFC/mL (Sac+). Para os camarões com 8 g a contagem de Víbrio total foi de 9,0 x 102 (est.) a 2,0 x 107, de < 6,0 a 4,02 x 106 UFC/mL (Sac-) e de < 6,0 a 2,0 x 10⁷ UFC/mL (est.) (Sac +). Os resultados mostram que os índices de colônias de Vibrio Sac- e Sac+ foram maiores no período chuvoso do que no de estiagem. Não houve relação entre o tempo de coagulação e as contagens de Vibrio na hemolinfa dos camarões. As espécies que predominaram nos períodos estudados foram: V. coralliilyticus, V. parahaemolyticus, Vibrio pelagius II, Vibrio alginolyticus, Vibrio mediterranei, Vibrio mimicus, Vibrio vulnificus B1.
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49

Purins, Leanne Roslyn. "Molecular characterisation of the transcriptional activator, HLYU, of Vibrio cholerae O1 /." Title page, abstract and table of contents only, 2004. http://web4.library.adelaide.edu.au/theses/09PH/09php9857.pdf.

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Thesis (Ph.D.)--University of Adelaide, School of Molecular and Biomedical Science , Discipline of Microbiology and Immunology, 2005.
"May, 2004" Includes corrigenda. includes bibliographical references (leaves 118-156).
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50

Nygren, Erik. "A mouse model for direct evaluation of cholera vaccines /." Göteborg : Dept. of Microbiology and immunology, Institute of Biomedicine, The Sahlgrenska Academy at University of Gothenburg, 2009. http://hdl.handle.net/2077/19376.

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