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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Structural studies of the cholera toxin catalytic subunit /

O'Neal, Claire J. January 2005 (has links)
Thesis (Ph. D.)--University of Washington, 2005. / Vita. Includes bibliographical references (leaves 186-202).
52

Genômica comparativa de vibrios / Genomic comparative of vibrios

Graciela Maria Dias 21 July 2010 (has links)
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.
53

VÃbrio em camarÃo e na Ãgua de trÃs fazendas de carcinicultura do Cearà / Vibrio in shrimp and water from three shrimp farms in CearÃ

Anahy de Souza Lima 03 June 2007 (has links)
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.
54

A study of the pharmacological effects of bacterial toxins

Dohadwalla, A. N. January 1970 (has links)
No description available.
55

Genetic and biochemical studies of Vibrio alginolyticus glutamine synthetase

Maharaj, Romilla January 1988 (has links)
Bibliography: pages 181-201. / A genomic library of the collagenolytic Vibrio alginolyticus strain was established in Escherichia coli HB101 employing the positive selection vector pEcoR251. A glutamine synthetase (GS) gene, glnA was identified by complementation of the glnA deletion in E. coli ET8051 glnA, glnL, glnG deletion strain. The glnA region of V. alginolyticus was cloned on a 5.7 kb insert in pRM210.
56

Studies on the Vibrio alginolyticus sucrose utilization system cloned into Escherichia coli

Scholle, Renate Regina January 1989 (has links)
Bibliography: pages 143-154. / This dissertation forms part of the study on the molecular biology of the aerobic, collagenolytic, halotolerant, gram-negative organism Vibrio alginolyticus. The cloning, expression and regulation of the v. alginolyticus sucrose utilization system in Escherichia coli is discussed and the results of a molecular analysis of the sucrase gene (scrA) are presented. The clone pVSlOO, containing a sucrose utilization system, was isolated from a genomic library of v. alginolyticus. Plasmid pVSlOO was mapped and the origin of its insert determined by Southern blotting and DNA hybridization. The number and sizes of the polypeptide products encoded by plasmid pVSlOO were determined by DNAdirected cell-free protein synthesis. The capsule, produced by transformed and untransformed E. coli JA221 cells, was shown to be independent of the presence of plasmid pVSlOO. The sucrase activity assay was optimized with respect to time, pH, temperature and salt requirements.
57

Eficacia de la fagoterapia contra la infección inducida por Vibrio alginolyticus en cultivos de Artemia franciscana

Fernández Espinel, Carla Ivonne January 2016 (has links)
Evalúa la eficacia de la fagoterapia para reducir la mortalidad en Artemia franciscana causada por una infección inducida con la cepa de Vibrio alginolyticus. Desarrolla las infecciones experimentales en recipientes con 100 ml de agua de mar estéril suplementada con peptona a una densidad de 100 nauplios por ml. Se toma como LD50, la dosis de inóculo bacteriano que causó el 50% de muerte de nauplios de Artemia franciscana a las 48 horas y realiza la cinética de infección de Vibrio alginolyticus para evaluar cómo disminuye la tasa de supervivencia en el cultivo experimental. Para evaluar la eficacia de la fagoterapia del fago Va1 se inoculan diferentes dosis del bacteriófago para determinar cuál de ellas es más efectiva y se trabaja con esta dosis para determinar en qué tiempo de comenzada la infección se debe inocular el bacteriófago para obtener una mayor supervivencia de los nauplios. Demuestra que el fago Va1 es efectivo para aumentar la supervivencia, una sola dosis de 400µl con un título de 8.108 UFP/mL al comienzo de la infección es suficiente para eliminar la infección inducida con Vibrio alginolyticus. El tiempo de aplicación del bacteriófago no puede exceder las 15 horas post infección, ya que dentro de este intervalo de tiempo el índice de supervivencia se encuentra entre 75 y 97%, resultados que muestran diferencias significativas con respecto al control. Concluye que el uso de bacteriófagos como tratamiento contra vibriosis utilizando a Artemia franciscana como modelo biológico es efectivo para la prevención y control de Vibrio alginolyticus. / Tesis
58

An Evaluation of the Role of Temperature on the Safety and Quality of Raw Shellstock Oysters and Bluefish

Lorca, Tatiana A. 16 November 2000 (has links)
Raw oyster shellstock was subjected to abuse conditions (7, 13, and 21°C) and sampled over a ten day storage period to gather scientific data to aid in determining whether spoilage occurred in the raw product over time before proliferation of pathogenic flora (Vibrio vulnificus) made the product unsafe. Spoilage was evaluated through pH measurements of a homogenate of the shucked meat and liquor. The olfactory acceptability of the raw oysters was evaluated in concert with the microbial and chemical evaluations. At all storage conditions, halophilic bacteria outgrew V. vulnificus by a minimum of 1 log CFU/g oyster (Colony Forming Units per gram) (p < 0.05). Olfactory acceptability was below 40% when V. vulnificus growth was at its highest (p < 0.05). Refrigerated storage should be considered a CCP for raw shellstock since even moderate temperature control kept V. vulnificus below 10<sup>4</sup> approximately 1-2 Logs below the estimated infective dose for the majority of the population. / Master of Science
59

Lipids and Phospholipase Activity of Vibrio Cholerae

Brian, Buford Leo 08 1900 (has links)
One purpose of this investigation is to determine the fatty acid and lipid content of typical Vibrio cholerae cells. The comparison of cholera lipid constituents with those of closely-related bacteria might be of taxonomic value. Furthermore, chemical characterization of the cholera vibrio could provide useful criteria for identification of these disease-producing microorganisms.
60

Pesquisa de Vibrio parahaemolyticus em atum (Thunnus spp) comercializado na zona sul do município de São Paulo ? SP / Study of Vibrio parahaemolyticus in tuna (Thunnus spp) traded in the south region of the city of São Paulo ? SP.

Chen, Juliana 01 October 2004 (has links)
Com o objetivo de avaliar a presença de Vibrio parahaemolyticus em atum, foram coletadas 112 amostras, sendo 56 durante o inverno de 2003 (junho a julho) e 56, durante o verão de 2003-2004 (dezembro a janeiro), vendidos em diversos pontos comerciais da zona sul da cidade de São Paulo. Foi determinado o Número Mais Provável (NMP) de Vibrio parahaemolyticus, comparando a contaminação observada durante os dois períodos. As cepas foram estudadas quanto à produção de urease, ao fenômeno de Kanagawa e à sensibilidade a antibióticos. Apenas 2,68% das amostras foram positivas (3/112). Dessas, duas amostras foram coletadas no verão e uma, no inverno. A amostra positiva obtida no inverno apresentou 3 NMP/g, as outras duas, coletadas durante o verão, apresentaram respectivamente, 3 e 4 NMP/g. Todas as cepas isoladas de Vibrio parahaemolyticus foram negativas ao teste de Kanagawa e não produtoras de Urease, não apresentando nenhuma característica patogênica. Todas as cepas foram resistentes a ampicilina, eritromicina, estreptomicina penicilina G, polimixina B e vancomicina. Apresentaram susceptibilidade intermediária a ciprofloxacina, kanamicina e gentamicina, e sensibilidade a ácido nalixídico, cloranfenicol e tetraciclina. Conclui-se que, nas condições desse estudo, o sashimi de atum revelou-se um alimento de baixo risco ao consumidor, no que se refere a infecção (toxigênica) por Vibrio parahaemolyticus / In order to evaluate the presence of Vibrio parahaemolyticus in tuna traded in retail stores in the south region of the city of São Paulo, 112 samples were collected, 56 during the winter of 2003 (June and July) and 56, during the summer of 2003-2004 (December to January). Most probable number (MPN) of Vibrio parahaemolyticus was determined, comparing the contamination level observed in the two periods. Strains were analyzed in relation to urease production, Kanagawa phenomenon and sensitivity to antibiotics. Only 2.68% of the samples were positive (3/112), two of them collected in the summer, and one of them, in the winter. The positive sample obtained in the winter presented 3 NMP/g, and the other two samples, collected in the summer, presented 3 and 4 NMP/g, respectively. All Vibrio parahaemolyticus samples isolated were Kanagawa, urease negative. Therefore, they did not present any pathogenic characteristic. All strains were resistant to ampicillin, erythromycin, streptomycin, penicillin G, polymyxin B and vancomycin. They presented intermediate susceptibility to ciprofloxacin, kanamycin and gentamicin, and sensitivity to nalidixic acid, chloramphenicol and tetracycline. It may be concluded that, in the conditions of this study, tuna sashimi is considered low risk food in relation to toxigenic infection by Vibrio parahaemolyticus

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