Die Besiedlung des kindlichen Darms beginnt unmittelbar mit der Geburt. Hier findet der erste Kontakt mit verschiedensten Bakterien statt. Deshalb war die zentrale Fragestellung unserer Untersuchung, wie sich die Bakterienarten bei den Geburtsmodi unterscheiden und wie sich die bakterielle Zusammensetzung im Stuhl von Neugeborenen im Laufe der Jahre verändert hat. Wir untersuchten die Stuhlproben von 42 Neugeborenen, wovon 22 vaginal und 20 per Sectio entbunden wurden, am ersten, zweiten und dritten Lebenstag auf Bakterienwachstum. Es wurden die aufgetretenen Bakteriengattungen mittels Kultur bestimmt und von den aufgetretenen Staphylokokken und Enterokokken die Arten und deren Resistenzen mittels des Phönix-Vollautomaten untersucht. Wir konnten zeigen, dass im Gegensatz zu früheren Untersuchungen heutzutage vermehrt Staphylokokken den Darm von Neugeborenen besiedeln. Außerdem fiel auf, dass per Sectio entbundene Kinder eine verminderte Heterogenität in ihrer Stuhlflora haben und erst später besiedelt werden als vaginal entbundene Kinder.

Allergic diseases, for example asthma and eczema, are nowadays considered belonging to the most common chronic diseases amongst children in the West, but the cause for this increase in allergy prevalence is unknown. Since studies have indicated a connection between children's exposure of microorganisms during infancy and risk of developing allergic disease, it is suggested that this exposure is a crucial factor in question of allergy development or not. Other studies have established differences in microflora composition between healthy children and children with allergic disease, and several studies have shown that probiotic therapy can give positive results in both prevention and treatment of allergic diseases. The aim of this master's thesis was to develop a method, using PCR and denaturing gradient gel electrophoresis, to study the diversity of Lactobacillus spp. in fecal samples retrieved from a study of the probiotic strain L. reuteri ATCC 55730. The developed method was successful in detecting lactobacilli in fecal samples, but three other bacterial genera commonly found in humans were also amplified. Comparison of average numbers of detected bacterial strains and lactobacilli strains between samples belonging to the probiotics and placebo groups, respectively, showed higher numbers for the probiotics group. Also, the only fecal samples that contained L. reuteri belonged to the probiotics group. Although the results are far from statistically significant, they support the theories that probiotics may influence the intestinal microbiota.

Les élevages des poissons sont soumis à des épisodes de mortalité anormale. Les bactéries du genre Vibrio sont connues comme des pathogènes opportunistes et ont été associées à ces épisodes de mortalité. Pour faire face à ces problèmes d’épizooties, les pisciculteurs ont le plus souvent recours à l’utilisation des antibiotiques. Néanmoins, des abus dans son utilisation ont malheureusement conduit à l’apparition des souches résistantes et à des fréquents échecs de traitement. Actuellement, les traitements par des bactéries lactiques probiotiques permettent d’améliorer la qualité des alevins produits pour les besoins de l’aquaculture, tout en limitant le recours aux antibiotiques. Pour qu’un micro-organisme soit reconnu comme étant potentiellement probiotique, une évaluation de ce produit basée sur plusieurs critères doit être établie. Dans une première étape, nous avons sélectionné et caractérisé 55 souches de bactéries lactiques isolées en écloserie. Le premier critère de sélection a porté sur l’inhibition de souches de vibrions pathogènes in vitro. Les bactéries lactiques ayant un effet anti Vibrio ont subi des tests de formation de biofilms et des tests de caractérisations phénotypiques, enzymatiques, physiologiques et génétiques, afin de procéder à leur identification. Puis des tests de compétition avec V. aligonlyticus ont été pratiqués in vivo sur des larves d’Artemia. Ce travail nous a permis de sélectionner la souche Lactobacillus casei (X2), car elle présentait la meilleure combinaison de propriétés requises pour un probiotique. Elle possède en effet une bonne activité antagoniste, elle n’est pas hémolytique, elle présente une forte adhérence sur plaque polystyrène et elle offre la meilleure protection contre V. alginolyticus lors du test de challenge avec Artemia. Dans une deuxième étape, la souche retenue (La. casei X2) et une autre déjà commercialisée sous le nom de Bactocell (Pediococcus acidilactici) ont été testées sur des larves de bar, afin d'évaluer les effets sur la qualité des alevins, leur réponse immunitaire et la microflore associée. Nous avons vérifié que les deux probiotiques (La. Casei et P. acidilactici) diminuaient la charge en vibrions et en microflore totale chez les larves de bar. La souche P. acidilactici a également affecté les profils de la communauté bactérienne intestinale des larves de bar. Par contre, La. casei n’a pas affecté la structure de la communauté bactérienne, bien que la souche soit présente chez les larves au jour 40 à une concentration élevée. Ces deux bactéries ont pu améliorer la croissance en longueur des larves aux jours 30 et 45 et la croissance en poids au jour 20. L’étude de l’influence des deux probiotiques sur des marqueurs de la physiologie des larves a montré qu’au jour 41, P. acidilactici était plus efficace que La. casei dans la régulation du stress oxydatif. Néanmoins, P. acidilactici a engendré des effets inflammatoires chez les larves à j20, et elle a induit un retard dans le développement osseux. Bien que La. casei ait accéléré le processus d’ossification chez les larves à j20, l’étude histopathologique a révélé une forte incidence des malformations vertébrales avec les larves à j62. A l’inverse, les larves alimentées avec P. acidilactici ont présenté un taux supérieur d’ossification normale et complète. / Diseases cause major production losses in fish farms. Bacteria of the genus Vibrio are known as opportunistic pathogens, and have been associated with mass-mortality episodes. To cope with these disease outbreaks, fish farmers often resort to the use of antibiotics. However, preventive overuse has led to the emergence of resistant strains and frequent treatment failures. Probiotic lactic acid bacteria are increasingly used to improve the quality of seed production in aquaculture, while limiting antibiotic treatments. Microbial strains must fulfil several criteria to be evaluated as potential probiotics.In a first step, we selected and characterized 55 strains of lactic acid bacteria isolated from fish hatchery. The first selection criterion focused on the in-vitro inhibition of pathogenic Vibrio strains. Lactic acid bacteria with antagonistic properties were tested for biofilm formation. The strains were characterised with the phenotypes, based on enzymatic and physiological tests, and identified by genotyping. In-vivo challenges with Vibrio aligonlyticus were then performed on Artemia. Lactobacillus casei X2 was thus selected, due to the best combination of the attributes that are required for probiotics. The strain showed antagonistic activity, adhered strongly to polystyrene plate, and secured Artemia with the best protection against V. alginolyticus. In a second step, La. casei X2 and a commercial strain of probiotics (Bactocell, Pediococcus acidilactici) were tested on European sea bass larvae, with a view to assess the effects on alevin quality, immune response and associated microbiota. Both of the lactic acid bacteria, La. casei and P. acidilactici, decreased the bacterial load and Vibrio in sea bass larvae. P. acidilactici changed significantly the profile of the bacterial community associated with fish larvae, compared to the control group. La. casei did not affect the structure of the bacterial community, although the strain was detected at high concentration in the larvae at 40 day post hatch (dph). Both probiotic treatments increased fish larval growth in body mass at 20 dph, and in length at 30 and 45 dph. Two physiological markers for gene expression suggested that P. acidilactici was more efficient than La. casei for the regulation of oxidative stress in sea bass at 41 dph. P. acidilactici induced some delay in bone development, and inflammatory signs were observed in the larvae at 20 dph. Though La. casei accelerated the early ossification process in the larvae by 20 dph, the histopathological study revealed a high incidence of vertebral malformations at 62 dph. In contrast, the treatment with P. acidilactici produced the highest proportion of fish with normal and complete ossification.

Submitted by Michele Mologni (mologni@unoeste.br) on 2019-01-29T18:40:59Z No. of bitstreams: 1 Sandra Cristina Genaro.pdf: 1632390 bytes, checksum: 89f6ec224705d20a5ce967976b70a4c3 (MD5) / Made available in DSpace on 2019-01-29T18:40:59Z (GMT). No. of bitstreams: 1 Sandra Cristina Genaro.pdf: 1632390 bytes, checksum: 89f6ec224705d20a5ce967976b70a4c3 (MD5) Previous issue date: 2018-11-22 / Among the existing types, colorectal cancer (CRC) affects approximately one million people per year, considered the second most common cause of death among women and the third most prevalent in men. Risk factors are genetic syndromes; inflammatory bowel diseases; family history; sedentary lifestyle; obesity, low fiber, high saturated fats, smoked foods or built-in food, excess red meat (> 300g/week), preparation mode in high temperatures and on the ember; medications; smoking, and excessive alcohol. These factors alter the intestinal microbiome which is colonized by pathogenic bacteria capable of provoking a local inflammatory response that, in chronic cases, activates carcinogenic components. Probiotics have increasingly attracted the attention of researchers in order to understand their action in the intestinal microbiota, aiding in the prevention and treatment of colorectal cancer. The objective of this study was to evaluate the effect of a probiotic In aggressiveness of the chemically induced colorectal tumor in rats. Twenty-five male Fisher 344 rats, 250 g, receiving ration and water ad libitum, were randomly divided into 5 groups (5 rats/group): GControl, without treatment; GTumor, tumor induction; GTumor + 5FU, tumor induction, 5-fluorouracil applied; GTumor + prob, tumor induction, supplemented with probiotic; GTumor + 5-FU + prob, tumor induction, applied 5-fluorouracil, supplemented with probiotic. For tumor induction, the animals received four intraperitoneal injections of the carcinogen 1.2-dimethylhidrazine (DMH) at the dose of 20 mg/kg body weight, being two applications per week, for four consecutive week. A 15-day interval was given and DMH applications were repeated for another four week. After 5 weeks of the last dose of the carcinogen, the treatment was initiated for ten consecutive weeks, applying a weekly dose of 15 mg/kg body weight of 5-fluorouracil, Intraperitoneal route and commercial probiotic containing Lactobacillus and Bifidobacterium at the dose of 1x109 UFC, administered by gavage, daily. Datas were analyzed by the analysis of variance One Way and the averages compared by the test of Dunnett. Used Software Statistical GraphPad Prism. The histopathologic analyses evaluated by the Chi-square ratio test. It was considered type-I error of 5% as statistically significant. Compared to the GTumor, the GTumor + prob (P < 0,0373) and GTumor + 5-FU + prob (P < 0,0003) showed attenuating effect on the aggressiveness of the colorectal tumor, with a reduction in the count of Aberrant Crypts Foci; and lower percentage of malignant neoplastic lesions in the GTumor + prob (40% of low-grade tubular adenoma, 40% of carcinoma in situ, 20% of low-grade adenocarcinoma) and GTumor + 5-FU + prob (40% of low-grade tubular adenoma and 60% of carcinoma in situ). The suplementation with probiotic has the potential to decrease the formation of aberrant crypts and mitigate the progression of tumor malignancy, potentializing the antitumor effect of 5-fluorouracil chemotherapy in the colic segments. / O câncer colorretal (CCR) acomete aproximadamente um milhão de pessoas por ano, considerado a segunda causa de morte mais comum entre mulheres e a terceira mais prevalente em homens. Os fatores de risco incluem as síndromes genéticas; doenças inflamatórias intestinais; história familiar; sedentarismo; obesidade, alimentação pobre em fibras, rica em gorduras saturadas, alimentos defumados ou embutidos, carne vermelha em excesso (>300g/sem), modo de preparação em altas temperaturas e na brasa; medicamentos; tabagismo e bebida alcoólica em excesso. Esses fatores levam a alteração da microbiota intestinal a qual é colonizada por bactérias patogênicas capazes de provocar uma resposta inflamatória local que, em casos crônicos, ativam componentes cancerígenos. Os probióticos têm atraído cada vez mais a atenção de pesquisadores com o intuito de compreender a sua ação na microbiota intestinal, auxiliando na prevenção e tratamento do câncer colorretal. O objetivo desse estudo foi avaliar o efeito de um probiótico na agressividade do tumor colorretal induzido quimicamente em ratos. Vinte e cinco ratos machos Fisher 344, 250 g, recebendo ração e água ad libitum, foram divididos aleatoriamente em 5 grupos (5 ratos/grupo): GControle, sem tratamento; GTumor, indução do tumor; GTumor+5FU, indução do tumor, aplicado 5-Fluorouracil; GTumor+Prob, indução do tumor, suplementado com probiótico; GTumor+5-FU+Prob, indução do tumor, aplicado 5-Fluorouracil, suplementado com probiótico. Para indução do tumor colorretal, os animais receberam quatro injeções intraperitoneais do carcinógeno 1,2-dimetilhidrazina (DMH) na dose de 20 mg/kg de peso corporal, sendo duas aplicações por semana, durante quatro semanas consecutivas. Deu-se um intervalo de 15 dias e as aplicações de DMH foram repetidas por mais quatro semanas. Após 5 semanas da última dose do carcinógeno, iniciou-se o tratamento por dez semanas consecutivas, com 5-Fluorouracil: uma dose de 15 mg/kg por semana, via intraperitoneal e probiótico comercial: 1x109 UFC, diariamente, por gavagem. Os dados foram analisados pela Análise de Variância One Way e as médias comparadas pelo teste de Dunnett. Utilizado software estatístico GraphPad Prism. As análises histopatológicas avaliadas pelo teste de proporção Qui-quadrado. Foi considerado erro tipo-I de 5% como estatisticamente significante. Comparados com o GTumor, o GTumor+Prob (p<0,0373) e GTumor+5-FU+Prob (p<0,0003) exibiram efeito atenuante na agressividade do tumor colorretal obervando redução na contagem de Focos de Criptas Aberrantes; e menor porcentagem de lesões neoplásicas malignas no GTumor+Prob (40% de adenoma tubular de baixo grau, 40% de carcinoma in situ, 20% de adenocarcinoma de baixo grau) e GTumor+5-FU+Prob (40% de adenoma tubular de baixo grau e 60% de carcinoma in situ). Concluimos que a suplementação com probiótico tem potencial para diminuir a formação de criptas aberrantes e amenizar a progressão da malignidade do tumor, potencializando o efeito antitumoral da quimioterapia com 5-Fluorouracil nos segmentos cólicos.

Gastrointestinal microflora has been shown to have a bi-directional relationship with the host immune system. A variety of fermentable carbohydrate polymers largely pass through the small intestine, providing fermentable substrates for gut microflora. Dietary fibre supplementation may provide a strategy for manipulating the intestinal bacterial profile, changing the interaction with the mucosal immune system, thereby modulating the host immune system. We used a BBc rat animal model to evaluate the effects of oat bran and wheat bran dietary fibre on the immune system. Previous collaborative efforts have shown that these dietary fibres can change the intestinal microflora, with wheat bran fibre showing a greater ability to influence colonic microbial community diversity. We have shown that dietary wheat bran fibre led to reduced IL-4 levels in the liver and T lymphocyte numbers in the Mesenteric Lymph Node and may be involved in reduced IgA levels in the cecal contents. In addition, IgA in the cecal contents was decreased while MLN B cell numbers increased in response to dietary wheat bran fibre. It was observed that neither wheat bran or oat bran treatments exerted any pro-inflammatory effects, with oat bran actually improving antioxidant status. These results suggest that both oat and wheat bran fibre treatments induce changes in the intestinal microflora, and that the microflora changes due to wheat fibre are associated with immunomodulatory effects on the host. This type of dietary fibre supplementation could ultimately provide a potential strategy for promoting health through microflora-associated effects on the immune system.

Coeliac disease (CD) is a disorder resulting from interactions between diet, genome and immunity. This research seeks to further our understanding of the pathology of CD in regard to its secondary effects on the diversity of enteral microflora via changes in immune tolerance. It proposes that enteral mucosal pro-inflammatory change in CD is associated with a decrease in microbial diversity whilst remission from inflammation may result in an increase in enteral microbial diversity that could contribute to the restoration of tolerance. The first study analyses whether remission from active CD is associated with change in generic enteral microbial diversity by assessing people at diagnosis and following their response to gluten exclusion. A comparison is made to people without CD consuming a ’normal diet’. DGGE profiling of faecal microflora in subjects with CD at diagnosis (confirmed by serology and by duodenal biopsy) and over three consecutive months on a gluten-free diet (GFD) was performed and profiles were compared with those of age and gender matched control subjects taken at monthly intervals. Diversity of faecal microflora (measured as Simpsons Index ) was significantly lower in people with CD than in control subjects. It was possible to distinguish the profiles of coeliac subjects at diagnosis from those obtained after three months on a GFD but it was not possible to distinguish between the samples from control subjects taken at monthly intervals. The profiles of CD subjects after three months on a GFD were more dissimilar to those of the control subjects than those obtained prior to dietary treatment, chiefly on the basis of three bands that were not found in the faeces of any control subjects. The second study analyses dietary intake to determine if a lack of nutrients at diagnosis (before institution of a GFD) and at monthly intervals for three consecutive months post diagnosis (on a GFD) exists, as it is known that CD is associated with nutrient deficiencies resulting from malabsorption due to intestinal inflammation and damage. Subjects completed a customised food questionnaire at each sampling period. Dietary intake was analysed using Foodworks Professional 2007. Significant differences were identified in gluten, starch and carbohydrate intake but not in other macronutrients. Contrary to established literature, these analyses identified few significant differences in micronutrient intake within coeliac subjects over time, however, significant differences were found in iron and sodium.

Die Besiedlung des kindlichen Darms beginnt unmittelbar mit der Geburt. Hier findet der erste Kontakt mit verschiedensten Bakterien statt. Deshalb war die zentrale Fragestellung unserer Untersuchung, wie sich die Bakterienarten bei den Geburtsmodi unterscheiden und wie sich die bakterielle Zusammensetzung im Stuhl von Neugeborenen im Laufe der Jahre verändert hat. Wir untersuchten die Stuhlproben von 42 Neugeborenen, wovon 22 vaginal und 20 per Sectio entbunden wurden, am ersten, zweiten und dritten Lebenstag auf Bakterienwachstum. Es wurden die aufgetretenen Bakteriengattungen mittels Kultur bestimmt und von den aufgetretenen Staphylokokken und Enterokokken die Arten und deren Resistenzen mittels des Phönix-Vollautomaten untersucht. Wir konnten zeigen, dass im Gegensatz zu früheren Untersuchungen heutzutage vermehrt Staphylokokken den Darm von Neugeborenen besiedeln. Außerdem fiel auf, dass per Sectio entbundene Kinder eine verminderte Heterogenität in ihrer Stuhlflora haben und erst später besiedelt werden als vaginal entbundene Kinder.