Thesis (Ph. D.)--West Virginia University, 2005. / Title from document title page. Document formatted into pages; contains ix, 166 p. : ill. Includes abstract. Includes bibliographical references.

Le virus de la rougeole est un agent pathogène responsable d’immunosuppressions transitoires mais sévères chez les individus infectés. L’infection par ce virus peut ainsi mener à l’établissement d’infections secondaires opportunistes, souvent décrites chez les patients rougeoleux. Cependant, la contribution du virus de la rougeole sur des infections secondaires à l’échelle de la cellule co-infectée n’a jamais fait l’objet d’études. Notre équipe à précédemment démontré que le virus de la rougeole induit une autophagie productive dans les cellules infectées, requise pour une réplication optimale du virus. À l’opposé, certains pathogènes comme la bactérie Salmonella typhimurium sont restreints par l’autophagie. Le but de cette thèse est d’étudier la contribution de l’autophagie sur la prolifération bactérienne en condition de co-infection avec le virus de la rougeole. Au cours du projet, nous avons identifié que dans les cellules co-infectées avec le virus de la rougeole, la bactérie Salmonella typhimurium hyperprolifère. Cette prolifération intense prend place essentiellement dans des cellules multinucléées géantes (syncytia) formées par le virus. En outre, la bactérie, normalement localisée dans une vacuole cellulaire, se localise dans le cytosol de ces syncytia et semble insensible à l’autophagie. Au cours de cette thèse, nous avons identifié que le facteur antimicrobien TBK1 pourrait être détourné par l’infection virale, contribuant ainsi à l’échappement de la bactérie à l’autophagie. Ce travail de thèse met ainsi en évidence une nouvelle possibilité d’échappement de bactéries à l’autophagie lors d’une co-infection virale. / Measles virus is a pathogenic agent responsible for transient but severe immunosuppression in infected individuals. The infection can lead to the establishment of secondary infections, frequently described in measles virus infected patients. Nevertheless, Measles virus contribution to secondary infection at cell scale level have never been studied yet. Our team has previously described that Measles virus induce a fully functional autophagy in infected cells, which is mandatory for an efficient viral replication. On the opposite, some pathogens, as the bacteria Salmonella typhimurium are restricted by autophagy. The aim of this PhD project is to study the contribution of autophagy on bacterial proliferation upon Measles virus co-infection at cell level. During this project, we have identified that in Measles virus coinfected cells, Salmonella typhimurium hyperproliferates. This exacerbated proliferation takes place in multinucleated giant cells induced by the virus, which are called syncytia. In addition, the bacteria, which is normally localized in cellular vacuole, is localized directly inside the cytosol of syncytia. Furthermore, cytosolic bacteria appears to be insensitive to autophagy. During this PhD project, we have identified that the cellular factor TBK1 could be hijack by the viral infection. Thus, this could allow the auophagic escape of the bacteria. This study highlight a new opportunity of autophagic escape of bacteria during a viral co-infection.

Orientador: Raphael Lucio Andreatti Filho / Banca: Adriano Sakai Okamoto / Banca: Julio Lopes Sequeira / Banca: Maristela Lovato / Banca: Guilherme Augusto Marietto Gonçalves / Resumo: Utilizou-se o método de Separação Imunomagnética associada a Bacteriófago para detectar os seguintes sorovares: Salmonella Heidelberg, Salmonella Enteritidis e Salmonella Typhimurium, em amostras de sobrecoxas de frango contaminadas artificialmente. Para certificarmo-nos da eficiência do método, comparamos esta técnica com os testes de diagnóstico usuais para este patógeno: a análise bacteriológica padrão, que inclui a etapa de pré-enriquecimento, enriquecimento seletivo, realização de testes bioquímicos de triagem e sorologia, e a reação em cadeia da polimerase (PCR). Na avaliação da capacidade dos testes na detecção de Salmonella em carne de frango, submetemos amostras de sobrecoxas de frango à contaminação artificial com 5, 10 e 100 UFC/25mL de bactéria, para cada um dos sorovares listados anteriormente, totalizando 270 análises, divididas em 90 testes para cada um dos três sorovares, e assim comparamos os resultados obtidos com a análise bacteriológica, PCR e o teste de Separação Imunomagnética associada a Bacteriófago. Ao aferirmos os resultados constatamos que a Separação Imunomagnética associada a Bacteriófago é equiparável ao método bacteriológico recomendado pelo Ministério da Agricultura, Pecuária e Abastecimento (MAPA) e com a técnica de PCR, pois 99,6% das amostras foram positivas ao realizarmos o teste de Separação Imunomagnética associado a Bacteriófago e apenas uma amostra de Salmonella Enteritidis foi negativa neste ensaio, na concentração de 5 UFC/25mL. Já no método bacteriológico verificamos 95,5% de positividade, com nove amostras negativas para S. Heidelberg, duas negativas para S. Enteritidis e duas no ensaio com S. Typhimurium. Na técnica de PCR obtivemos 98,5% de positivos, com uma amostra negativa para S. Enteritidis na concentração de 5 UFC/25mL e três negativas para S. Typhimurium. O tempo despendido para a realização de cada teste foi aferido e constatamos... / Abstract: We used the Immunomagnectic Separarion Assay associated with Bacteriophage to detect the following serovars: Salmonella Enteritidis, Salmonella Heidelberg and Salmonella Typhimurium, in poultry drumstick samples artificially contaminated. We compared the efficiency of this technique to the usual diagnostic tests for Salmonella in food samples: the standard bacteriological analysis, which includes the step of pre-enrichment and selective enrichment, biochemical and serological screening tests, and polymerase chain reaction (PCR). To evaluate the tests capability of Salmonella detection poultry meat samples were submitted to artificial contamination with 5, 10 and 100 CFU/25mL of bacteria, for each of the serovars listed above, totaling 270 analyzes divided into 90 tests for each of the three serovars, and so compare the results obtained with the bacteriological analysis, PCR and Immunomagnetic Separation Bacteriophage assay. We found that the Immunomagnetic Separation Bacteriophage assay was comparable to bacteriological method recommended by the Ministry of Agriculture, Livestock and Supply (MAPA) and the PCR technique, because 99.6% of the samples were positive to accomplish Immunomagnetic Separation Bacteriophage assay and only a sample of Salmonella Enteritidis was negative in this test, in the concentration of 5 CFU/25mL. The bacteriological method check 95.5% positivity, with nine samples negative for S. Heidelberg, two negative for S. Enteritidis and two in the test with S. Typhimurium. In PCR 98.5% positives samples were obtained, with one S. Enteritidis negative sample in the concentration of 5 CFU/25ml and three negative samples for S. Typhimurium. The time for performing each test was measured and the Immunomagnetic Separation Bacteriophage assay was the most rapid test for Salmonella diagnosis, since 20 hours, the conventional bacteriological took 88h and PCR 44h approximately. In this study we confirm the effectiveness of the ... / Doutor

Made available in DSpace on 2014-06-11T19:23:46Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-05-25Bitstream added on 2014-06-13T20:51:04Z : No. of bitstreams: 1 avila_lg_me_jabo.pdf: 747621 bytes, checksum: 76d19c9f28a893a44749a9fd2afda1cb (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O estudo teve como objetivo avaliar as alterações clínicas e laboratoriais de bezerros infectados experimentalmente com Salmonella Typhimurium e verificar o efeito do tratamento desses bezerros com antibiótico florfenicol associado ou não à fluidoterapia. Para isso, foram constituídos quatro grupos experimentais, compostos por seis bezerros cada, os quais receberam, por via oral, aproximadamente 109 UFC de Salmonella Typhimurium (exceto o grupo 1) e que foram submetidos aos seguintes procedimentos: controle (grupo 1); infectados, mas sem tratamento (grupo 2); tratamento apenas com florfenicol (grupo 3) e tratamento com florfenicol associado à fluidoterapia (grupo 4). Todos os bezerros foram submetidos ao exame físico imediatamente antes da inoculação experimental e a cada 12 horas, até o sexto dia após a inoculação. Foram coletadas amostras de sangue, uma vez ao dia, para a realização de exames hematológicos, hemogasométricos, bioquímicos e proteinograma. Foram também coletadas, diariamente, amostras de fezes por meio de suabes retais para o isolamento de Salmonella através de exames microbiológicos. Durante a fase experimental, os animais foram alojados em bezerreiros individuais e não houve a ocorrência de óbito em nenhum dos grupos, mostrando que este sorotipo tem importância epidemiológica devido à eliminação do agente no ambiente ter ocorrido de forma intermitente ou contínua. A S. Typhimurium foi capaz de causar febre, diarréia de grau variável, tendência a leucocitose, diminuição do teor sérico de ferro, hipoglicemia e hiperfibrinogenemia. Os bezerros que receberam tratamento à base de florfenicol associado ou não à fluidoterapia tiveram menos dias de diarréia e febre e apresentaram menor período de excreção do agente etiológico pelas fezes. / The aim of the study was to evaluate clinical and laboratorial changes in experimentally Salmonella Typhimurium-infected calves and the effect of florfenicol antibiotic treatment associated or not to fluid therapy. Four experimental groups, comprising six calves, were formed. With the exception of group 1, animals orally received about 109 CFU of S. Typhimurium and underwent the following procedures: control (group 1), without any treatment (group 2), treatment with florfenicol only (group 3) and treatment with florfenicol associated to fluid therapy (group 4). All calves were submitted to physical examination before experimental inoculation and at every 24 hours up to the 6th day after infection. Blood samples were collected for hematological, hemogasometric, biochemical and protein analysis. Rectal swabs were performed for the isolation of Salmonella by standard microbiological techniques. The calves were maintained individually and there were no deaths during the experiment, which means that this sorovar has an epidemiological importance related to the intermitent or continuous elimination of the bacteria. S. Typhimurium experimental infection was able to cause fever, different degrees of diarrhea, increased values of leukocytes and fibrinogen concentration and decreased values of seric iron and glicemia. The groups treated with antibiotic associated or not to fluid therapy had a shorter period of diarrhea and elimination of the bacteria in the feces.

Orientador: José Jurandir Fagliari / Banca: Mario Roberto Hatayde / Banca: Roberto Calderon Gonçalves / Resumo: O estudo teve como objetivo avaliar as alterações clínicas e laboratoriais de bezerros infectados experimentalmente com Salmonella Typhimurium e verificar o efeito do tratamento desses bezerros com antibiótico florfenicol associado ou não à fluidoterapia. Para isso, foram constituídos quatro grupos experimentais, compostos por seis bezerros cada, os quais receberam, por via oral, aproximadamente 109 UFC de Salmonella Typhimurium (exceto o grupo 1) e que foram submetidos aos seguintes procedimentos: controle (grupo 1); infectados, mas sem tratamento (grupo 2); tratamento apenas com florfenicol (grupo 3) e tratamento com florfenicol associado à fluidoterapia (grupo 4). Todos os bezerros foram submetidos ao exame físico imediatamente antes da inoculação experimental e a cada 12 horas, até o sexto dia após a inoculação. Foram coletadas amostras de sangue, uma vez ao dia, para a realização de exames hematológicos, hemogasométricos, bioquímicos e proteinograma. Foram também coletadas, diariamente, amostras de fezes por meio de suabes retais para o isolamento de Salmonella através de exames microbiológicos. Durante a fase experimental, os animais foram alojados em bezerreiros individuais e não houve a ocorrência de óbito em nenhum dos grupos, mostrando que este sorotipo tem importância epidemiológica devido à eliminação do agente no ambiente ter ocorrido de forma intermitente ou contínua. A S. Typhimurium foi capaz de causar febre, diarréia de grau variável, tendência a leucocitose, diminuição do teor sérico de ferro, hipoglicemia e hiperfibrinogenemia. Os bezerros que receberam tratamento à base de florfenicol associado ou não à fluidoterapia tiveram menos dias de diarréia e febre e apresentaram menor período de excreção do agente etiológico pelas fezes. / Abstract: The aim of the study was to evaluate clinical and laboratorial changes in experimentally Salmonella Typhimurium-infected calves and the effect of florfenicol antibiotic treatment associated or not to fluid therapy. Four experimental groups, comprising six calves, were formed. With the exception of group 1, animals orally received about 109 CFU of S. Typhimurium and underwent the following procedures: control (group 1), without any treatment (group 2), treatment with florfenicol only (group 3) and treatment with florfenicol associated to fluid therapy (group 4). All calves were submitted to physical examination before experimental inoculation and at every 24 hours up to the 6th day after infection. Blood samples were collected for hematological, hemogasometric, biochemical and protein analysis. Rectal swabs were performed for the isolation of Salmonella by standard microbiological techniques. The calves were maintained individually and there were no deaths during the experiment, which means that this sorovar has an epidemiological importance related to the intermitent or continuous elimination of the bacteria. S. Typhimurium experimental infection was able to cause fever, different degrees of diarrhea, increased values of leukocytes and fibrinogen concentration and decreased values of seric iron and glicemia. The groups treated with antibiotic associated or not to fluid therapy had a shorter period of diarrhea and elimination of the bacteria in the feces. / Mestre

Os herbicidas são destinados ao controle das ervas daninhas e seu uso torna o fornecimento de alimentos abundante e livre de pragas, porém a exposição ocupacional e ambiental a esses compostos pode trazer riscos à saúde. O Brasil é o maior consumidor de praguicidas desde 2008, e os herbicidas correspondem por 45% do volume dessas substâncias. O tebutiurom e a trifluralina são herbicidas muito utilizados em culturas de cana-de-açúcar, e apesar de serem descritos como seletivos em seu mecanismo de ação, seus efeitos em organismos não alvo, como células humanas, são pouco conhecidos. O objetivo do trabalho foi avaliar os efeitos dos herbicidas tebutiuron e trifluralina em organismos não alvo. Para isso, utilizou-se a linhagem celular HepG2, e as concentrações testadas dos herbicidas foram de 1 a 100 ?mol/L e o tempo de exposição variou de 4 h à 14 dias de acordo com o ensaio. Utilizou-se também as linhagens TA98 TA100, TA97a e TA1535 da bactéria S typhimurium. Neste caso, as concentrações testadas dos herbicidas variaram de 0,1 à 5000 ?g/placa e o tempo de exposição foi de 66 h. As análises indicaram que o tebutiurom não apresenta potencial citotóxico, genotóxico, ou mutagênico nas condições testadas, evidenciando sua seletividade. Testes com a trifluralina, no entanto, mostraram que HepG2 apresentaram uma diminuição da capacidade em formar clones quando expostas à 100 ?mol/L por 14 dias, e uma redução na densidade celular quando expostas à 50 e 100 ?mol/L por 24, 48 e 72h. Tais efeitos ocorreram devido a uma diminuição da viabilidade celular, observada em 50 e 100 ?mol/L pelo ensaio MTT, e devido a um bloqueio no ciclo celular na fase S, evidenciado em 100 ?mol/L, ambos nos tempos de 24, 48 e 72h. O tipo de morte celular inicialmente observada foi a apoptose, através da marcação por anexina V em 100 ?mol/L após 48 e 72 h de exposição, e através da condensação e fragmentação nuclear em 100 ?mol/L após 24 e 48 h de exposição. Em 72 h, observou-se também necrose em 100 ?mol/L, por meio dos testes anexina V/PI e liberação de LDH. A morte celular pode estar relacionada à diminuição do potencial de membrana mitocondrial, observada em 50 e 100 ?mol/L após 24, 48 e 72h, e a um aumento na produção de espécies reativas, efeito observado em células expostas à 100 ?mol/L de trifluralina por 24 e 48 h. No entanto, observou-se que a via de resposta ao estresse oxidativo Keap1/Nrf2-ARE não foi ativada no tempo analisado de 24 h. Além disso, os testes de cometa e micronúcleo não indicaram potencial da trifluralina em provocar danos no material genético de HepG2. Complementarmente, o teste de Ames em linhagens de S typhimurium também não evidenciaram potencial mutagênico do herbicida. As análises com a trifluralina mostraram que o herbicida, apesar de não induzir genotoxicidade e mutagenicidade, possui potencial citotóxico em HepG2, indicando que pode afetar organismos não alvo, como células humanas / Herbicides are used to control weeds in agriculture. The use of these chemicals makes possible an abundant and pest free supply of food. However, occupational and environmental exposure to these compounds can lead to health risks. Brazil is the largest consumer of pesticides since 2008, and herbicides match for 45% of the volume of these substances. The tebutiurom and trifluralin herbicides are widely used in sugarcane crops, and although they are described as selective in its mechanism of action, effects on non-target organisms, such as human cells, are are poorly known. The aim of this work was to evaluate the effects of tebuthiuron and trifluralin herbicides on non-target organisms. To this end, we used the cell line HepG2, and herbicides were tested at concentrations of 1 to 100 ?M and the exposure time ranged from 4 h to 14 days in accordance with the assay. We also used the strains TA100 TA98, TA97a and TA1535 of the bacterium S. typhimurium. In this case, the herbicide concentrations tested ranged from 0.1 to 5000 ?g / plate and the exposure time was 66 h. Analyzes indicated that the tebutiurom has no cytotoxic, genotoxic or mutagenic potential at tested conditions, highlighting its selectivity. Tests with the Trifluralin, however, showed that HepG2 had a decreased ability in forming clones when exposed to 100 ?M for 14 days, and a reduction in cell density when exposed to 50 and 100 ?M of the herbicide for 24, 48 and 72h. These effects occurred due a decrease in cell viability observed at 50 and 100 ?M by MTT assay, and due to a block in the cell cycle into S phase, as evidenced in 100 ?M, both at 24, 48 and 72h. The type of cell death detected first was apoptosis. It was observed by staining with annexin V in cells exposed to 100 ?M of trifluralin during 48 and 72 h, and through the nuclear condensation and fragmentation in exposure with 100 ?M during 24 and 48 h of exposure. At 72 h, necrosis was also observed in 100 ?M through the annexin V / PI and LDH assays. Cell death occurrence may be associated with decreased mitochondrial membrane potential observed in 50 and 100 ?M after 24, 48 and 72h of exposure, and also may be associated with incresed production of reactive species, observed in cells exposed to 100 ?M of trifluralin for 24 and 48 h. However, it was observed that the oxidative stress response pathway Keap1 / Nrf2-ARE was not activated within 24 hours. Furthermore, comet assay and micronucleus test indicated no potential of trifluralin in causing DNA damage of HepG2. In addition, the Ames test using S. typhimurium strains also showed no mutagenic potential of the herbicide. The analyzes showed that the trifluralin, despite not induce genotoxicity and mutagenicity, have cytotoxic potential in HepG2, indicating that can affect non-target organisms, such as human cells.

Infecções pulmonares de potros jovens por Rhodococcus equi resultam em grave pneumonia levando à morte um grande número de animais todos os anos. Até o momento não há nenhuma vacina aceita globalmente para a prevenção da rodococose equina. O único tratamento preconizado é baseado em antibioticoterapia, porém os protocolos clínicos são longos, de alto custo, com efeitos colaterais e tem favorecido a seleção de cepas resistentes aos antibióticos. Diversas estratégias no desenvolvimento de uma vacina segura e eficiente contra a rodococose foram propostas, porém, não induziram um efeito protetor considerável. O principal fator de virulência do R. equi descrito e amplamente estudado é a proteína vapA, no entanto, outras proteínas localizadas na ilha de patogenicidade estão presentes em amostras de R. equi virulento extraídos de animais infectados. Trabalhos recentes têm demonstrado a presença do gene vapG em todas as cepas virulentas e este gene é altamente expresso quando a bactéria reside no interior de macrófagos, tornando-o um possível alvo vacinal. Nosso grupo já possui experiência prévia no uso de linhagem de Salmonella enterica Typhimurium atenuada carreando a proteína vapA. Baseado nos resultados positivos obtidos, foi construída uma linhagem atenuada de S. enterica Typhimurium 3987 expressando a proteína vapG. A administração desta linhagem em camundongos foi capaz de induzir proteção contra R. equi virulento. Os resultados observados foram a colonização e persistência da Salmonella nos órgãos alvo, a redução da carga bacteriana de R. equi, e a indução de um perfil imune protetor semelhante ao observado em animais adultos resistentes. Observou-se o aumento da produção de IL-12p70 e IFN-, alem da presença de níveis aumentados de IL-4 e a redução dos níveis de TNF-. Observou-se também o aumento na subpopulação de células T auxiliares (CD4+) com perfil de memória, além de aumento na população de linfócitos B totais quando comparado aos grupos controles. Este conjunto de resultados indica que a imunização com Salmonella enterica Typhimurium expressando a proteína vapG gera uma resposta imune celular eficiente tornando esta linhagem uma possível candidata a vetor vacinal. Alem disso, sugere que outros antígenos do R. equi podem ser / Pulmonary infections in young foals by Rhodococcus equi result in severe pneumonia, leading to death a large number of animals every year. There is no globally accepted vaccine for the prevention of equine rhodococosis so far. To date, the only acceptable treatment is based on antibiotics, but the clinical protocols are long lasting, expensive, having side effects and favoring the emergence of drug resistant strains. Several strategies for developing a safe and effective vaccine against rhodococosis have been proposed, however, none has induced a significant protective effect. The main virulence factor of R. equi described and extensively studied is the protein vapA, although other proteins encoded by genes in pathogenicity islands are detected in samples of virulent R. equi, isolated from infected animals. Recent works have demonstrated that the vapG gene is present in all virulent strains, and that this gene is highly expressed when bacteria reside within macrophages, making it a potential vaccine target. Our group has already been working with an attenuated Salmonella enterica Typhimurium strain expressing the VapA protein. Even though our results were very promising, we decided to construct a second vaccine strain expressing the VapG protein. Based on the positive results, it was constructed an attenuated strain of S. enterica Typhimurium 3987 expressing the vapG protein. Interestingly, the VapG-expressing strain induced protection against virulent R. equi in mouse model of infection. We could observe colonization and persistence of Salmonella vaccine cells in target organs, with reduction of bacterial loads of R. equi and induction of a protective immune profile similar to that seen in resistant adult animals. We could also observe increased production of IL-12p70 and IFN- in addition to the presence of increased levels of IL-4 and reduced levels of TNF-. Moreover, we detected an increase in the subpopulation of T helper cells (CD4), with a profile of memory, as well as in the population of B lymphocytes, when compared to control groups. This set of results shows that immunization with Salmonella enterica Typhimurium expressing the VapG protein raises an efficient cellular immune response, making this strain a potential candidate for vaccine vector. Furthermore, this work suggests that other R. equi antigens may be taken into account for vaccine construction, besides the VapA protein utilized in the majority of studies.

O presente estudo buscou avaliar os efeitos dos Mananoligossacarídeos (MOS) como aditivo alimentar no desempenho de primíparas suínas em final de gestação e em lactação, bem como no desempenho e na saúde dos leitões até os 65 dias de idade. O experimento foi realizado no Laboratório de Pesquisa em Suínos (VNP-FMVZ-USP) Pirassununga SP. O delineamento experimental foi inteiramente casualizado em arranjo fatorial de tratamentos, sendo um fator o fornecimento dos MOS para fêmeas e o segundo para os leitões. Foram utilizadas 17 primíparas prenhes, tratadas a partir de 81 &plusmn;1,36 dias de gestação com 0,2% de MOS na dieta. Aos 82 &plusmn; 1,36 dias de gestação as fêmeas foram submetidas à coleta de sangue e à vacinação contra rinite atrófica progressiva, sendo pesadas quinzenalmente até a transferência para a maternidade, aos 109 &plusmn; 1,36 dias de gestação. Na segunda quinzena as fêmeas tratadas apresentaram uma vantagem numérica no ganho de peso médio diário (P=0,063). Durante o parto foram colhidas amostras de sangue e colostro para titulação de anticorpos contra o antígeno vacinal, sendo consideradas positivas 66,67% das fêmeas MOS e 42,86% das fêmeas controle. Os leitões aleitados por fêmeas tratadas tiveram um maior ganho numérico de peso na primeira semana (p=0,0614), significativo na segunda semana (p=0,047). Na terceira semana foi introduzido o segundo fator através do oferecimento de alimento sólido (0,4% de MOS). No período total, do nascimento aos 21 dias, foi observada uma vantagem numérica (p=0,0989) no ganho de peso a favor dos leitões de fêmeas MOS. As fêmeas, contudo, não diferiram quanto à variação de peso ou consumo durante a fase de lactação. Aos 23 &plusmn; 1,91 dias de idade dos leitões foi realizado o desmame abrupto com a transferência dos leitões para unidade de creche, onde foram alojados em gaiolas para 4 animais. O peso ao desmame foi maior nos leitões aleitados por fêmeas tratadas (p<0,0001), bem como em todas as pesagens semanais até a quinta semana pós-desmame. O consumo na primeira semana sofreu influência da suplementação de MOS nas fêmeas e do maior peso à desmama se mostrando superior nesses animais (P=0,049) influenciando diretamente o ganho de peso, superior na segunda semana (p=0,002). O MOS para os leitões aumentou o consumo de alimento (p=0,0784), e a conversão alimentar na segunda semana (p=0,0103). Aos 14 dias pós-desmame foram colhidas amostras de sangue para hemograma e realizada a aplicação oral de 108 UFC de Salmonella Typhimurium. Foram observadas diariamente a consistência das fezes por 28 dias e aferidas as temperaturas retais por 9 dias. Leitões tratados com MOS e os leitões oriundos de fêmeas MOS tenderam a apresentar o pico de hipertermia mais cedo que os demais (p=0,0629 e p=0,0976, respectivamente) e os leitões alimentados com MOS tenderam a ter uma temperatura de pico mais baixa (p=0,0989). Na última semana os leitões de fêmeas MOS apresentaram um maior consumo (p=0,0007) e uma incidência de Salmonella numéricamente inferior em linfonodos mesentéricos e nas fezes colhidas aos 36 dias pós-desafio. Pode-se concluir que a suplementação de MOS para primíparas prenhes e lactentes pode melhorar o desempenho e a saúde entérica de seus leitões nas fases de aleitamento e creche. / The present study evaluated the effects of mananoligossacarides (MOS) as a feed additive on the performance of primiparous sows in late gestation and lactation, as well as on performance and health status of their progeny up to 65 days of age. The experiment was conducted in the Laboratory of Swine Research (FMVZ/USP) Pirassununga SP. For this purpose a completely random factorial design was used, factors which corresponded to (1) feeding sows with MOS and (2) feeding piglets with MOS, characterizing 4 treatments: MM Feeding MOS to both sows and piglets, MC Feeding MOS only to the sows, CM Feeding MOS only to piglets, CC Control diets for both sows and piglets. A total of seventeen pregnant gilts were used, and divided into 2 groups: MOS (n=9) and Control (n=8). MOS gilts had 0,1% MOS added to their diets from 81 &plusmn; 1,36 days of gestation onward. On day 82 &plusmn; 1,36 blood was collected and vaccination against Progressive Atrophic Rhinitis was conducted. Animals were weighted biweekly until 109 &plusmn; 1,36 days of gestation, when transference to the farrowing unit was conducted. Between the first and second weighing, MOS gilts show a numerical advantage in daily weight gain (p=0,063). At farrowing, blood and colostrum samples were collected for determination antibodies titles against vaccine antigen, being considered positive 66,67% and 42,86% of MOS and Control sows, respectively. Piglets nursed by MOS sows had a numerical advantage in weight gain in the first week (p=0,0614), with statistical significance in the second week (p=0,047). On the third week, the second factor was introduced by the offering of solid feed (0,4% MOS). During the suckling period, from birth to 21 days of age, a numerical advantage in weight gain was observed for MOS sows piglets (p=0,0989). The sows themselves did not differ in weight change or feed consumption. At 23 &plusmn; 1,91 days of age, weaning was conducted, as piglets were transferred to nursing facilities and allocated in pens of 4 animals. Weight of MOS sows piglets was higher at weaning (p<0,001) and until the 5th week port-weaning. Feed consumption was affected by MOS supplementation of sows and by the higher weaning weight (p=0,0049), directly influencing weight gain, which was superior in the 2nd week. Feeding MOS to piglets enhanced feed consumption (p=0,0784) and feed conversion (p=0,0103) on the 2nd week. At 14 days of age, blood samples were collected for hemogram analysis and an oral dose of 108 CFU of Salmonella Typhimurium administered. Fecal consistency and rectal temperature were evaluated for 28 and 9 days, respectively. Piglets treated with MOS and MOS sows\' piglets tended to show a peek of hyperthermia earlier (p=0,0629 e p=0,0976, respectively). Piglets fed with MOS tended to show a lower temperature peek (p=0.0989). In the last week, MOS sows\' piglets show a higher feed consumption (p=0.0007) and a numerically inferior Salmonella incidence in mesenteric lymph nodes and feces 36 days after the bacterial challenge. In conclusion, supplementing primiparous sows with MOS during gestation and lactation can enhance their body weight gain and the performance and intestinal health of the offspring during the suckling and nursing period.

O estudo fundamentou-se na utilização de probióticos como promotores de crescimento alternativos na alimentação de suínos dada a proibição, por parte da União Européia, do uso de alguns antibióticos, que podem causar resistência aos antimicrobianos e riscos à saúde humana pelo consumo da carne. O experimento foi conduzido no Laboratório de Pesquisa em Suínos (LPS), com 160 leitões desmamados aos 23 dias de idade até os 138 dias de idade. O delineamento experimental foi o de blocos ao acaso em função do peso e sexo, sendo a unidade experimental considerada a baia com 4 animais, constituindo, portanto, 5 repetições por tratamento. Aos 51 dias de idade os animais foram inoculados com uma cepa de Salmonella Typhimurium via oral. Os tratamentos foram: PA 44: Probiótico A: 4 Kg/tonelada de ração, dos 23 aos 44 dias de idade; PB 44: Probiótico B: 2 Kg/ tonelada de ração, dos 23 aos 44 dias de idade; PA 65: Probiótico A: 4 Kg/tonelada de ração, dos 23 aos 44 e 2 kg/tonelada de ração dos 45 aos 65 dias de idade; PB 65: Probiótico B: 2 Kg/tonelada de ração, dos 23 aos 44 e 1 kg/tonelada de ração dos 45 aos 65 dias de idade; PA 138: Probiótico A: 4 Kg/tonelada de ração, dos 23 aos 44 e 2 kg/ tonelada de ração dos 45 aos 138 dias de idade; PB 138: Probiótico B: 2 Kg/tonelada de ração, dos 23 aos 44 e 1 kg/tonelada de ração dos 45 aos 138 dias de idade; controle positivo: ração com antimicrobiano e sem probióticos e controle negativo: ração sem antimicrobiano e sem probióticos. Foram analisados os parâmetros peso, ganho de peso, consumo de ração e conversão alimentar. Aspectos clínicos e sanitários também foram avaliados, incluindo freqüência de diarréia, temperatura retal, swabs retais para verificação da freqüência da salmonela nas fezes e parâmetros sanguíneos. As variáveis foram analisadas por medidas repetidas no tempo com contrastes. Foi utilizado o SAS 9.0. Em relação ao peso médio, observou-se, no período de creche, que o controle positivo se sobressaiu frente aos probióticos, mas no período de crescimento, por volta dos 106 dias de idade, os grupos se igualaram, não havendo diferenças significativas. No período total de creche e crescimento/terminação, o ganho de peso dos animais do controle positivo foi numericamente superior comparativamente aos probióticos (p=0,0876 para o probiótico A e p=0,0635 para o probiótico B). O consumo de ração foi menor para o controle negativo em relação aos probióticos. A conversão alimentar foi melhor para o controle positvo em relação aos probióticos, na fase de creche. Na freqüência de diarréia o efeito do desafio programado foi evidenciado, mostrando no controle negativo maior freqüência, ressaltada principalmente pela classificação em fezes líquidas, em comparação aos probióticos e controle positivo. A temperatura retal e a presença do agente nas fezes não se mostraram diferentes nos tratamentos, o mesmo ocorrendo com relação aos parâmetros sanguíneos. Portanto, as evidências encontradas quanto aos parâmetros clínicos e sanitários demonstraram de uma maneira geral, que os probióticos e os antimicrobianos podem agir de forma diferenciada, mas apresentando as mesmas respostas que repercutem em desempenhos semelhantes até o final da fase de terminação. Concluiu-se na avaliação de desempenho associada aos aspectos econômicos, que o probiótico A, dentre os tratamentos, foi mais viável, com a administração até 44 e 65 dias de idade dos leitões. A continuidade dos estudos com probióticos é necessária, dada a variabilidade de fatores que interferem no seu melhor aproveitamento como promotor de crescimento. / The study was based on the use of probiotics as growth promoter in the swine feeding due to the prohibition, by the European Union, on the use of some antibiotics by its possibility of causing antimicrobial resistance and risks for human health by meat consumption. The experiment was conducted in LPS, with 160 piglets weaned at 23 days of age until 138 days of age. The experimental design was a randomized block according to weight and sex, the experimental unit considered was the pen holding 4 animals each, thus with 5 repetitions per treatment. At 51 days of age the animals were inoculated with a strain of Salmonella Typhimurium orally. The treatments were: PA44= Probiotic A: 4 kg/ton of ration, from 23 to 44 days of age; PB44= Probiotic B: 2 Kg/ton of ration, from 23 to 44 days of age; PA65= Probiotic A: 4 kg/ton of ration from 23 to 44 days of age and 2 kg/ton of ration from 45 to 65 days of age, PB65= Probiotic B: 2 kg/ton of ration, from 23 to 44 days of age and 1 kg/ton of ration from 45 to 65 days of age; PA138= Probiotic A: 4 kg/ton of ration from 23 to 44 days of age and 1 kg/ton of ration from 45 to 138 days of age; PB138= Probiotic B: 2 kg/ton of ration from 23 to 44 days of age and 1 kg/ton of ration from 45 to 138 days of age; Positive Control= ration with antimicrobial and no probiotics and Negative Control= ration with no antimicrobials nor probiotics. The parameters analyzed were weight, weight gain, ration intake and feed conversion. Clinical and sanitary aspects were also evaluated, diarrhea frequency, rectal temperature, rectal swabs for salmonella verification and blood parameters. The variables were analyzed by repetitive measures on time with the established contrasts. SAS 9.0 was used. Regarding average weight, it was observed, during the nursery period, that the positive control stood out compared to the probiotics, but during growing, around 106 days of age, the groups equaled, with no significant differences. During the total period of nursery and growing/finishing, the weight gain from the animals of the positive control was numerically superior compared to the probiotics (p=0,0876 for probiotic A and p=0,0635 for probiotic B). Feed intake was lower for negative control when compared to probiotics. In the nursery period feed conversiom was better than the positive control in relation to probiotics. In the diarrhea frequency the effect from the programmed challenge was evidenced; showing a higher frequency in the negative control, emphasized mainly for the liquid feces classification in comparison to the probiotics and positive control. The rectal temperature and the presence of the agent in the feces did not differ between treatments, as well as the blood parameters. Therefore, the evidence found regarding clinical parameters and health in general demonstrated that probiotics ant antiotics may act differently, but with the same answer that echo in similar performaces until the end of the finishing period. In conclusion, the evaluation of performance associated with economic aspects, among the treatments, with the probiotics A, both 44 and 65, was better than the positive control. The continuation of studies with probiotics is necessary, given the variability of factors that interfere with its best use as growth promoter.

T lymphocytes are an essential component of the adaptive immune response and are highly versatile in function. Each T cell has a unique T cell receptor that can recognize an antigenic peptide in the context of the major his to compatibility complex (MHC) encoded molecules, thus offering a high degree of specificity to the immune response. T cells play a central role in the development of an effective host immune response and the quantitative and qualitative regulation of the T cell response is critical. T cells develop in the thymus, an important primary immune organ, where immature thymocytes undergo differentiation and maturation. Through the process of thymic differentiation, immature cluster of differentiation (CD)4-CD8- thymocytes progress to a CD4+CD8+ stage and are subjected to positive and negative selection to give rise to MHC restricted, single positive CD4+ or CD8+ naive T cells that emigrate from the thymus and populate the peripheral lymphocyte pool. Thymic atrophy is well known to occur naturally during the process of aging with thymocyte depletion and reduced thymic output. Along with age associated changes leading to atrophy, the thymus is exquisitely sensitive to starvation and several stresses. In addition, thymic atrophy is a characteristic feature during several viral, bacterial and parasitic infections. Egress of immature thymocytes, loss of thymic populations due to sensitivity to glucocorticoids and cytokine modulation, etc. have been variously proposed to be involved in this process. However there is limited understanding on the numerous mechanisms involved and the crosstalk between these diverse pathways. In this study, a model for thymic atrophy during acute Salmonella enterica serovar Typhimurium (S. typhimurium) infection was developed. S. typhimurium is a Gram negative bacterium that resides and grows in intracellular compartments within host cells. It causes gastroenteritis in humans but leads to typhoid like disease in mice, similar to that caused by S. typhi in humans. Initially, it was established that acute infection of C57BL/6 mice with 108 CFU S. typhimurium, via the oral, i.e. the physiological, route of infection leads to extensive depletion (8-10 fold) of thymocytes in an infection-dependent manner. Infected mice had higher CFU burden in the Peyer’s patches, spleen, liver, and mesenteric lymph node (MLN) as compared to the thymus. The thymic atrophy was dependent upon the infection caused by live S. typhimurium since oral feeding of mice even with higher doses (1010 CFU) of heat-killed bacteria did not lead to thymic atrophy. The susceptible populations in the thymus were identified by staining for expression of CD4 and CD8 on cell surface using specific monoclonal antibodies tagged to fluorophores, e.g. Fluorescein isothiocyanate (FITC) and phycoerythrin (PE), respectively. The double labelled samples were analyzed by flow cytometry. Interestingly, significant death of CD4+CD8+, the major population of thymocytes, but not single positive thymocytes or peripheral lymphocytes (MLN and spleen cells), was observed at later stages during infection. To gain greater understanding of the processes involved, the mechanisms leading to thymic atrophy were investigated. To this purpose, small molecule inhibitors and mice lacking key molecules important for the immune response were utilized. Also, various assays to assess death of thymocytes, including analysis of death markers such as Annexin V based detection of membrane flipping and caspase activation were performed. I. The extrinsic death pathway involving Fas/FasL interactions is a major death pathway. Therefore, the expression and functional role of the components of the pathway in this model of thymocyte death was investigated. It was observed that thymocytes from infected mice expressed more Fas and Fas ligand (FasL) on their surface than cells from uninfected mice. To address the role of the death receptor, Fas, infection studies were performed with lpr mice that lack functional Fas expression. The depletion of CD4+CD8+ thymocytes in lpr mice was comparable to that in C57BL/6 mice indicating that it was independent of the Fas pathway. However, extensive loss of mitochondrial membrane potential was observed upon analysis with mitochondrial potential specific dyes MitoTracker Red and DiOC6. Most likely, the intrinsic death pathway involving mitochondrial depolarization is involved in this model of thymic atrophy. II. Since thymocytes are known to be sensitive to glucocorticoids both in vitro and in vivo, the involvement of the same in this model of thymic atrophy was assessed. The amounts of cortisol, a glucocorticoid, as detected by ELISA, were elevated during infection. To investigate the functional implication of the increase in cortisol, studies were performed using RU486, a glucocorticoid receptor antagonist. RU486 did not modulate cortisol amounts and treatment of mice with RU486 did not affect CFU burden or survival of mice. However there was a moderate rescue in the number of viable CD4+CD8+ thymocytes, with only a 3-4 fold drop as compared to the 8-10 fold drop in vehicle treated infected mice. III. As glucocorticoids appeared to play a partial role in this model, it was reasonable to assume that other pathways were also involved in the thymic atrophy. The quantitative and qualitative modulation of the cytokine milieu has a profound effect upon the thymus. In fact, inflammatory cytokines, Tnfα and Ifnγ, increased upon infection. In order to study the role of Ifnγ mediated inflammatory responses in this model, infection studies with Ifnγ-/- mice were performed. Ifnγ-/- mice had higher CFU and lower survival; however the drop in thymocyte numbers was 3-4 fold as compared to the 8-10 fold drop in the infected C57BL/6 mice, again indicating a partial involvement of the Ifnγ mediated pathways. In order to study the interactions, if any, between the two pathways mentioned above, corticosteroid signaling was blocked in the Ifnγ-/- mice with RU486. Upon infection, the number of CD4+CD8+ thymocytes was significantly higher in Ifnγ-/- mice treated with RU486 (~1.5 fold drop in viable thymocyte numbers) along with lower caspase 3 activity and mitochondrial damage. Importantly, cortisol amounts in infected Ifnγ-/- mice were comparable to those in infected C57BL/6 mice and the administration of RU486 did not modulate Tnfα and Ifnγ cytokine amounts in sera. Thus, the glucocorticoid and Ifnγ mediated pathways are parallel but synergize in an additive manner to induce death of CD4+CD8+ thymocytes during S. typhimurium nfection. IV. Although thymic atrophy is known to occur, a detailed characterization of cell surface changes in thymocyte populations has not been performed. To investigate this aspect, thymocytes and MLN cells from uninfected and infected animals were stained for cell surface expression of CD3, CD4, CD5, CD8, CD24, CD25, CD44, CD69, MHC I and MHC II. This analysis was initially performed by studying the changes in expression of these molecules within the total thymocyte and MLN populations. Although there was no change in the expression of CD25 and MHC II in the total thymocyte population upon infection, CD24 expression reduced, whereas, the expression of CD3, CD5, CD44, CD69 and MHC I increased. Notably, changes in the frequency of expression of CD3, CD69 and MHC I were observed before the development of extensive thymic atrophy. The depletion of majority of the CD4+CD8+ thymocytes enriches the mature CD4+ or CD8+ thymocyte population This was corroborated with the observation that, upon in vitro stimulation with PMA and Ionomycin (pharmacological agents used to activate T cells) the residual thymocytes from infected mice produced more IL2 compared to thymocytes from uninfected mice. Subsequently, cells were stained with anti-CD4-FITC, anti-CD8-PE and a third biotinylated antibody, which was detected by a streptavidin-APC conjugate, against one of the remaining six markers. This three colour analysis made it possible to determine the changes in the expression of the third marker in each of the CD4-CD8-, CD4+CD8+, CD4+ and CD8+ populations upon infection. Distinct differences were observed in the phenotypes of uninfected and infected CD4+CD8+ thymocytes and the latter were CD3high, CD5high, CD24low, CD69high and MHC Ihigh indicating that the surviving population had a possibly more mature phenotype. Also, the changes in the phenotypes of the thymocyte populations were dependent upon the extent of thymic atrophy as indicated by time course and CFU studies with C57BL/6 and BALB/c mice respectively. Finally, the roles of glucocorticoids, Ifnγ and Nos2 in modulation of expression of these markers during infection were addressed. Interestingly, the expression of CD3, CD24 and MHC class I significantly correlated with increase in the number of surviving thymocytes upon inhibition of glucocorticoids signaling and in Ifnγ-/- mice. The implications of these changes in the thymocyte surface phenotype during thymic atrophy are discussed. V. Finally, the roles of downstream signalling molecules in S. typhimurium induced thymic atrophy were studied. Although the MAP kinase family members, Erk, Jnk and p38 have been implicated to play a role in the positive and/or negative selection of thymocytes during development, their role in infection induced thymocyte depletion has not been studied. Interestingly, the amounts of Jnk and pJnk, but not p38, increased in thymocytes upon infection. Importantly, pJnk amounts increased predominantly in CD3-/low thymocytes during infection. Furthermore, inhibition of Jnk signalling, using a specific inhibitor SP600125, lead to an increase in survival of CD4+CD8+ thymocytes during infection due to multiple reasons: lowering of cortisol, Tnfα and Ifnγ amounts, and better maintenance of thymic architecture. Thus, inhibition of Jnk mediated signaling protected CD4+CD8+ and CD3-/low thymocytes from death during S. typhimurium infection. Overall, the main conclusions of this study are as follows: First, extensive analysis of the surface phenotype of cells during thymic atrophy throws light on the sensitive and resistant thymocyte populations, thus offering a potential predictive marker profile. Second, glucocorticoids, Ifnγ and, importantly, Jnk mediated signaling play functional roles in the death of immature CD4+CD8+ thymocytes during S. typhimurium infection. The mechanistic details uncovered in this study may be important in designing effective strategies for reducing thymic atrophy during other infections. In fact, enhancement of thymic output may lead to greater numbers and diversity of thymic T cell emigrants in the periphery which is likely to enhance host responses during infections.