Seventeen strains of multi drug-resistant strains were isolated from aquaculture farms in previous study, and 82% (14/17) of these strains are belong to Vibrio species, which is one of the major pathogens in the aquaculture farms. Vibrio disease (vibriosis) which caused by the Vibrio will cause the fish skin ulcer with bleeding and gastrointestinal symptoms such as swelling. The highest mortality rate of Vibrio infected marine fish is up to 100%. Two vibriophages, Vibrio parahaemolyticus vibriophage £pVP2 and Vibrio alginolyticus vibriophage £pVA2, were isolated from aquaculture environments in this study. The morphology of vibriophage was examined by electron microscopy. The £pVP2 phage has an oval head with a tail and six tail fibers. As £pVA2, an icosarhedral head with an short tail is observed. In the DNA electrophoresis analysis, a fragment at 17.8k bp was observed in both £pVA2 and £pVP2 sample. Restriction endonuclease digestion pattern revealed that the £pVA2 vibriophage DNA can be cut into various small size of DNA fragments by EcoR I and Xba I endonuclease. In the host-range analysis, £pVP2 can infect Vibrio parahaemolyticus and Vibrio alginolyticus, while £pVA2 and £pVP2 cannot infect other Vibrio spp., Pasteurella, E. Coli, and antibiotic-resistant bacteria isolated from aquaculture farms. £pVA2 and £pVP2 can survive at the temperature below 65¢XC and 63¢XC, respectively. To obtain the maximum proliferation of vibriophage, different conditions were tested, including infection time point, host bacteria age, MOI (multiplicity of infection) and various mediums. Vibriophage £pVA2 was proliferated under following conditions: (1) phage was add to the medium with host seed together; (2) the overnight cultured host bacteria was used as seed; (3) the host cells were infected at MOI= 10-6; (4) MSWYE media was used as culture media. Vibriophage £pVP2 was proliferated following £pVA2 conditions but MOI values was 10-4.

Submitted by Irene Nascimento (irene.kessia@ufpe.br) on 2016-09-28T17:50:15Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Tese Edivânia.pdf: 9678189 bytes, checksum: bc6e8c52a38eb49d616a9e268bd0a048 (MD5) / Made available in DSpace on 2016-09-28T17:50:15Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Tese Edivânia.pdf: 9678189 bytes, checksum: bc6e8c52a38eb49d616a9e268bd0a048 (MD5) Previous issue date: 2016-02-26 / PRH / A exploração da energia de petróleo e gás é um campo de importância atual no desenvolvimento da economia mundial a qual tem tomado gradualmente o centro das atenções nos ambientes econômico e científico, elevando a demanda por tecnologias no desenvolvimento de materiais mais resistentes como os aços da classe API. As plataformas de prospecção e produção de petróleo no mar, oleodutos e gasodutos em operação, são fabricados a partir de chapas com diferentes processos de soldagem. Estes equipamentos, quando submersos em água do mar, estão susceptíveis a corrosão por fatores diversos como zona termicamente afetada e salinidade. Esse conjunto de fatores pode enfraquecer o material, principalmente na região da junta de solda podendo ocasionar a nucleação e propagação de trincas em regiões preferenciais. A degradação de materiais metálicos pode tornar-se ainda mais severa quando houver associação do meio corrosivo com micro-organismos os quais se aderem às superfícies e, através do seu metabolismo modificam as condições do meio podendo comprometer alterar a durabilidade e desempenho dos materiais. Neste trabalho foi obtida uma melhor compreensão sobre a ação das bactérias redutoras de sulfato e do Vibrio alginolyticus isoladamente e em consórcio, na corrosão de corpos de prova com juntas de solda do aço API 5L X80 em presença de água do mar. Para tanto, foram expostos corpos de prova do aço X 80 em sistemas contendo água do mar estéril, acrescida dos respectivos micro-organismos, além de um sistema abiótico. Foram feitas quantificações de bactérias sésseis e planctônicas, determinação das taxas de corrosão, ensaio de impacto Charpy e tração, observação das superfícies por microscópio eletrônico de varredura (MEV). Os resultados mostraram que a adesão microbiana e as taxas de corrosão não foram afetadas pela presença da solda e que os micro-organismos provocaram um efeito passivante, na corrosão por perda de massa, porem a observação das superfícies por MEV mostrou ataque por corrosão localizada. Quanto às propriedades mecânicas, os corpos de prova com solda, expostos ao sistema contendo Vibrio alginolyticus apresentara uma queda na absorção de energia, mostrando um enfraquecimento do material nessas condições. / The exploitation of oil and gas energy is a current important field in the development of the world economy which has gradually taken center stage in the economic and scientific environments, increasing the demand for technologies in the development of more resistant materials such as grade steels API. The platforms of oil exploration and production offshore, oil and gas pipelines in operation are made from sheets with different welding processes. These devices, when submerged in seawater, are susceptible to corrosion by several factors such as heat affected zone and salinity. This set of factors can weaken the material, especially in the solder joint in the region may cause the nucleation and propagation of cracks in preferred regions. Deterioration of metallic materials may become even more severe when the corrosive environment associated with micro-organisms which adhere to surfaces and through metabolism modifying the conditions of the environment can compromise alter the durability and performance of the materials. In this work we obtained a better understanding of the action of sulfate-reducing bacteria and Vibrio alginolyticus alone and in consortium, the corrosion test specimens with steel solder joints API 5L X80 in the presence of seawater. For both, it was exposed X 80 steel specimens in water the barren sea, plus the respective micro-organisms, as well as an abiotic system. measurements were made of sessile and planktonic bacteria, determination of corrosion rates, Charpy impact test and pull, observation of surfaces by scanning electron microscope (SEM). The results showed that the microbial adhesion and corrosion rates were not affected by the presence of solder, and that micro-organisms caused a passivating effect on the corrosion weight loss, but the observation of the surface by SEM showed attack by pitting. As for the mechanical properties, the samples with solder, exposed to the system containing Vibrio alginolyticus presented a drop in energy absorption, showing a weakening of the material in these conditions.

Submitted by (edna.saturno@ufrpe.br) on 2017-02-14T15:03:25Z No. of bitstreams: 1 Joana angelica L V Carvalho.pdf: 451922 bytes, checksum: 66f7ebcb01d8574ab7c4cced0c81dce6 (MD5) / Made available in DSpace on 2017-02-14T15:03:25Z (GMT). No. of bitstreams: 1 Joana angelica L V Carvalho.pdf: 451922 bytes, checksum: 66f7ebcb01d8574ab7c4cced0c81dce6 (MD5) Previous issue date: 2011-02-10 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This study aimed to evaluate the survival of Litopenaeus vannamei shrimp larvae treated with probiotic bacteria and subsequently infected by Vibrio harveyi and Vibrio alginolyticus. Shrimp were kept in two 80L tanks under similar culture conditions, but only one tank was previously treated with commercial probiotic (Bacillus spp.) added daily in the water at a concentration of 105 CFU/ml. This protocol was maintained until the animals reach the stage of development needed for the infection experiments by Vibrio spp. Three independent infection experiments were performed: Zoea1 to Zoea3, Mysis1 to Mysis3 and Postlarvae (PL)10 to PL14 with the following treatments with four replicates each: only V. harveyi; commercial probiotic + V. harveyi; only V. alginolyticus; commercial probiotic + V. alginolyticus; and without Vibrio spp. and probiotic (Control). In the experiment with PL, only the treatments with V. harveyi; commercial probiotic + V. harveyi and control were used. Vibrio species were inoculated only at the beginning of each experiment at a concentration of 107 CFU/ml. At the end of experiments, a sample of water and shrimp from each experimental unit was submitted to quantification of Vibrio spp. Additionally, was realized an antagonism test of Bacillus spp. against Vibrio spp. In the experiments with zoea and mysis, larvae cultured in treatment V. harveyi had a significantly lower survival when compared with treatments V. alginolyticus and control. There was a significant increase in survival of zoea and mysis larvae treated with probiotic + V. harveyi with 81.07 and 90.13%, differentiating the larvae infected only with V. harveyi with 12.80 and 69.13%, respectively. There were no significant differences in survival of postlarvae among treatments. Total Vibrio spp. counts decreased in the water and shrimp of treatments with the use of probiotic. The probiotic (Bacillus spp.) showed inhibitory activity against Vibrio spp. in vitro. The results indicated an increase in the survival of early larval stages (zoea and mysis) infected by V. harveyi after treatment with Bacillus spp. The administration of probiotic bacteria is a promising alternative for the prevention of Vibrio spp. in larviculture of L. vannamei. / O presente estudo teve como objetivo avaliar a sobrevivência de larvas de Litopenaeus vannamei tratadas com bactérias probióticas e posteriormente infectadas por Vibrio harveyi e Vibrio alginolyticus. Os camarões foram mantidos em dois tanques de 80L nas mesmas condições, mas apenas um deles foi previamente tratado com probiótico comercial (Bacillus spp.) adicionado diariamente na água na concentração de 105 UFC/ml. Este protocolo foi mantido até os animais alcançarem o estágio de desenvolvimento larval necessário para os experimentos de infecção por Vibrio spp. Foram realizados três experimentos independentes de infecção: Zoea1 a Zoea3, Mísis1 a Mísis3 e Pós-larvas (PL)10 a PL14 com os seguintes tratamentos com quatro repetições cada: somente V.harveyi; probiótico comercial + V. harveyi; somente V. alginolyticus; probiótico comercial + V. alginolyticus; sem Vibrio spp. e probiótico (controle). No experimento com PL, somente os tratamentos com V. harveyi; probiótico comercial + V. harveyi e controle foram utilizados. As espécies de Vibrio foram inoculadas apenas no início de cada experimento na concentração de 107 UFC/ml. Ao final dos experimentos, uma amostra de água e camarão de cada parcela experimental foi submetida à quantificação de Vibrio spp. Adicionalmente foi realizado um teste de antagonismo in vitro de Bacillus spp. contra Vibrio spp. Nos experimentos com zoea e mísis, as larvas cultivadas no tratamento V. harveyi apresentaram uma sobrevivência significativamente inferior quando comparadas com as dos tratamentos V. alginolyticus e controle. Houve um aumento significativo na sobrevivência de larvas zoea e mísis tratadas com probiótico + V. harveyi com 81,07 e 90,13%, em comparação com as larvas infectadas apenas com V. harveyi com 12,80 e 69,13%, respectivamente. Não foram observadas diferenças significativas na sobrevivência das pós-larvas entre tratamentos. A quantidade total de Vibrio spp. na água e camarões diminuiu nos tratamentos com o uso de probiótico. O probiótico (Bacillus spp.) apresentou atividade inibitória contra Vibrio spp. in vitro. Os resultados indicaram um aumento na sobrevivência dos estágios larvais iniciais (zoea e mísis) infectadas por V. harveyi após tratamento com Bacillus spp. A administração de bactérias probióticas é uma alternativa promissora para a prevenção de Vibrio spp. na larvicultura de L. vannamei.