Exposure to environmental pollutants poses numerous risk factors for human health, including increasing incidence of cardiovascular disease and diabetes. Persistent organic pollutants, such as polychlorinated biphenyls (PCBs) have been strongly linked to the development of these chronic inflammatory diseases and the primary route of exposure is through consumption of contaminated food products. Thus, the gastrointestinal tract is susceptible to the greatest levels of these pollutants and is an important facet to study. The first two hypotheses of this dissertation tested that exposure to PCBs disrupts gut microbiota directly (in vitro) and within a whole body system. PCB exposure disrupted microbial metabolism and production of metabolites (i.e. short chain fatty acids) in vitro. These disruptions in microbial populations were consistent in our mouse model of cardiometabolic disease, where we observed reductions in microbial diversity, an increase in the putative pro-inflammatory ratio of Firmicutes to Bacteroidetes, and reductions in beneficial microbial populations in exposed mice. Furthermore, observed greater inflammation was observed both within the intestines and peripherally in PCB exposed mice as well as disruptions in circulating markers associated with glucose homeostasis. Nutritional interventions high in prebiotic dietary fiber such as inulin may be able to attenuate the toxic effects of pollutant exposure. To test the hypothesis that consumption of the prebiotic inulin can decrease PCB-induced disruption in gut microbial and metabolic homeostasis, LDLr-\- mice were fed a diet containing inulin and exposed to PCB 126. Mice fed an inulin-containing diet and exposed to PCBs exhibited improved glucose tolerance, lower hepatic inflammation and steatosis, and distinct differences in gut microbial populations. Overall, these data suggests that nutritional intervention, specifically prebiotic consumption, may reduce pollutant-induced disease risk.

Orientador: Carlos Augusto Araujo Valadão / Resumo: A microbiota bacteriana intestinal dos equinos é heterogênea e complexa, podendo ser alterada por variações introduzida na dieta. A ingestão excessiva de carboidrato solúvel altera a microbiota intestinal com possíveis consequências catastróficas sistêmicas. Com este estudo, buscou-se avaliar as implicações da sobrecarga dietética experimental com amido sobre a microbiota fecal, correlacionando-a com a indução de laminite aguda. Foram utilizados 10 equinos (fêmeas ou machos castrados) SRD, idade média de 13±5,6 anos, e peso médio de 353±28 kg. Os animais foram distribuídos num delineamento inteiramente casualizado em arranjo fatorial 2x2 com medidas repetidas no tempo, sendo quatro grupos: controle (GC) - água (10L) por sonda nasogástrica e, após oito horas, solução fisiológica 0,9% (5L) pela cânula cecal; controle-tampão (GCT) - água (10L) por sonda nasogástrica e, após oito horas, solução alcalinizante (3,5g de Al(OH)3, 65,6g de Mg(OH)2) e 1,2g de simeticona pela cânula cecal; amido-controle (GAC) - amido (17,6g/kg) diluído em água (10L) e, após oito horas, solução fisiológica 0,9% (5L) pela cânula cecal; amido-tampão (GAT) - amido (17,6g/kg) diluído em água (10L) e, após oito horas, solução alcalinizante (3,5g de Al(OH)3, 65,6g de Mg(OH)2) e 1,2g de simeticona pela cânula cecal. Amostras de fezes foram colhidas da ampola retal em seis intervalos de tempo: T0 (basal); T8; T12; T24; T48; T72 horas, respectivamente, após a indução com amido. Em período imediato à colheita, av... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The horses’ intestinal bacteria microbiota is heterogeneous and complex and can variate according to diet changes. The excessive intake of soluble carbohydrate changes the intestinal microbiota with possible consequences systemic catastrophic. The goal of this study is to evaluate possible changes by starch overload in the fecal microbiota, correlating it with acute laminitis. Ten mixed breed horses (females and geldings), with age 13±5,6 years and weighting 353±28 kg, were used. They were distributed in a completely randomized design in 2x2 factorial arrangement with repeated measurements over time, being four groups: control (GC) - water (10L) by nasogastric tube and, after eight hours, physiological solution 0,9% (5L) by cecal cannula; buffer-control (GCT) - water (10L) by nasogastric tube and, after eight hours, buffer solution (3,5g of Al(OH)3, 65,6g of Mg(OH)2) and 1,2g of simethicone by cecal cannula; starch-control (GAC) - starch (17,6g/kg) diluted in water (10L) and, after eight hours, physiological solution 0,9% (5L) by cecal cannula; and buffer-starch (GAT) - starch (17,6g/kg) diluted in water (10L) and, after eight hours, buffer solution (3,5g of Al(OH)3, 65,6g of Mg(OH)2) and 1,2g of simethicone by cecal cannula. The fecal samples were collected from rectal ampoule in six different times: T0 (basal); T8; T12; T24; T48; T72 hours, respectively, after the starch overload. Following this, the lameness, the abdominal pain sings, the water and hay intake, the quality ... (Complete abstract click electronic access below) / Mestre

The prevalence of cardiovascular disease is a major public health concern worldwide. It has been theorized that diets rich in fruits and vegetables may be protective against the development of cardiovascular disease mainly through their high content of flavonoids. Flavonoids were thought to influence traditional risk factors of cardiovascular disease such as blood pressure, lipid profile, and systemic inflammation. Recent clinical studies have shown that this may not be the case. The production of trimethylamine oxide (TMAO) by the gut microbiota from dietary sources of choline has been associated with an increased risk of cardiovascular events. The objectives of this study were to determine the effects of a high flavonoid diet on gut microbiota composition and plasma trimethylamine oxide concentrations. Potential benefits of this research include the determination of a potential correlation between diet and markers of traditional and non-traditional risk factors for cardiovascular disease. Also, the effects that a high flavonoid diet has on the composition of the gut microbiota and plasma trimethylamine oxide concentrations may provide insight into possible dietary interventions to prevent cardiovascular disease.

The gut microbiome is a complex ecosystem of bacteria, viruses, and fungi that strongly influences animal health. The bacterial component, for example, contributes orders of magnitude more gene products to host physiology than the host genome; thus, changes to the composition of these bacterial communities can have profound influences on the health of the animal. By infecting and lysing their hosts, viruses (particularly viruses infecting bacteria or phages) can affect critical functions in these environments, yet the consequences of these infections remain to be fully described. Most studies investigating gut viromes to date have focused on double-stranded DNA (dsDNA) phages and, consequently, little is known about the smaller single-stranded DNA (ssDNA) phages, which also inhabit gut environments. In this study, we investigated ssDNA phages of the Microviridae family within the gut of an invertebrate organism, Ciona robusta, used as a model system to better understand gut microbial interactions. As a filter feeder, Ciona concentrates dissolved organics and microbes as part of its diet, yet maintains a microbiome distinct from the surrounding water column. We identified 258 unique ssDNA phage genomes representing a diversity of Microviridae subgroups including novel members of the established Gokushovirinae subfamily and several proposed phylogenetic groups (Alpavirinae, Aravirinae, Group D, Parabacteroides prophages, and Pequeñovirus). Over 70% of the genomes belonged to the Gokushovirinae; however, 155 of these genomes did not group with previously described sequences. Our results highlight an unprecedented diversity of ssDNA phages from an animal gut. Furthermore, comparative analysis between samples collected from Ciona specimens with full and cleared guts as well as the surrounding water indicated that Ciona retains a unique and highly diverse community of ssDNA phages. The present study significantly expands the known diversity within the Microviridae family and suggests that Ciona is a promising system for studying the role of ssDNA phages within animal guts.

Introduction: Diabetes is a global and rapidly increasing disease that in 2014 affected morethan 422 million people, and takes 1,2 million lives per year. The importance of identifyingnew ways to manage and prevent the disease has led science to a new area – modulation ofthe gut microbiota. It is well known that the composition of gut microbiota differs betweennon-diabetic and diabetic adults, and that nutrition is the main way to modulate gutmicrobiota composition. Food and lifestyle are of great importance for the development andtreatment of type 2 diabetes and pre-diabetes, but less is known about whether gut microbiotamodulation is mediating that link. Aim: The aim is to examine whether there is a scientifically well-supported link between diet,gut microbiota and the development or treatment of type 2 diabetes or pre-diabetes in humans. Methods: Systematic review with literature search via PubMed and Cochrane, following themanual from the Swedish Agency for Health Technology Assessment and Assessment ofSocial Services (SBU). Results: Of 12 articles finally included, two studies found a strong impact of diet on diabetesrelatedvariables via modulation of gut microbiota. Another four studies did not find anassociation, and six studies lacked sufficient data to be able to draw a conclusion. Dietinterventions and study design differed between studies, which led to heterogeneous results. Conclusions: This review demonstrates a large knowledge gap in how dietary modificationscan prevent or treat type 2 diabetes or pre-diabetes via changes in gut microbiota.

Neonates are generally thought to be more likely to suffer from gastrointestinal disease, owing in part to diminished immune cell function. To gain insight into the development of mucosal immune responses during early life, we developed a model of orogastric infection with the Gram-negative bacterium Yersinia enterocolitica using murine neonates. Remarkably, neonatal mice of either the BALB/c or C57BL/6 mouse strains showed markedly enhanced survival after infection compared to adult mice. Both innate and adaptive immune components appear to contribute to this phenomenon. First, the increased resistance of neonates coincided with containment of the bacteria in the intestinal tissue with low dissemination into the spleen and liver. In contrast, the bacteria readily disseminated to the peripheral tissues in adult mice. Flow cytometric and histological studies revealed increased levels of neutrophils and macrophages in the neonatal mesenteric lymph nodes (MLN) compared to adult mice. Similar results were obtained using two different high virulence Y. enterocolitica strains. The rapid mobilization of innate cells sequestered the bacteria to the intestinal tissue, since in vivo neutrophil depletion led to efficient dissemination of Y. enterocolitica to the spleen and liver of neonates. Together, these results support the hypothesis that the neonatal intestinal immune system is competent to mount a strong antibacterial response by rapidly mobilizing innate phagocytes and thereby confining the bacterial infection to the gut, resulting in a high level of resistance. Second, we have also demonstrated that the adaptive immune system was mobilized during primary and secondary infection with this pathogen and that some of these factors may contribute to the enhanced resistance of neonatal mice to infection. Primary infection in neonates led to increased levels of antigen presenting cells, B and T cells with an activated phenotype in the MLN. MLN CD4+ Th cells from infected neonates were found to produce greater levels of IFN-gamma and IL-17A, compared to CD4+ Th cells from adult mice. These Th responses are likely to be functionally significant because neonatal mice deficient in CD4+ T cells were found to be more susceptible than adult mice to primary infection. CD4+ T cells adoptively transferred into CD4 deficient mice rescued the majority of mice from lethal infection and led to the production of IFN-gamma and IL-17A by MLN cells. In addition, primary T cell-dependent IgG1 and IgG2a serum antibodies specific for the Yersinia immunogen LcrV were increased compared to adult mice, and the absence of B cells partially increased the susceptibility of neonatal mice to primary infection. During secondary infection, however, neonatal and adult mice mounted quantitatively and qualitatively similar Yersinia-specific memory antibody responses, demonstrating that infection with Y. enterocolitica promotes mature B cell responses in neonatal mice. Finally, primed neonatal and adult mice were protected from colonization of the Peyer's patches, weight loss and mortality after a lethal infection in adulthood, demonstrating the development of long-lived protective memory responses at the intestinal interface. Together, these results indicate that both B and T cell responses, in particular Th1 and Th17 associated immunity, are important for the development of long lasting immunity to this pathogen in early life. Third, infection of neonatal mice with a Y. enterocolitica strain deleted of the anti-inflammatory protein YopP led to massive infiltration and/or accumulation of innate phagocytes in the intestine and MLN. This effect was not detectable in infected adult mice. Thus, we have identified a novel negative regulator of intestinal inflammation which might be valuable in preventing or ameliorating inflammatory conditions. This model system has revealed the unprecedented potential of neonatal mice to develop protective inflammatory innate and adaptive immunity at mucosal surfaces. The combined results presented here demonstrate that neonatal mice may be well equipped to mount robust innate and adaptive intestinal inflammatory responses that are highly protective toward Y. enterocolitica. These findings have implications for understanding how pediatric intestinal adaptive immune responses develop in response to naturally occurring gastroenteric pathogens and offer a new biological platform for development of vaccines aimed at improving mucosal and systemic immunity in early life.

HIV infects over 33 million people worldwide with a new infection occurring every 9 seconds. Sex is the primary mode of transmission and the majority of new infections occur during unprotected sexual contact between an HIV-infected individual and an uninfected sexual partner(s) since HIV infected individuals tend to shed virus in their genital secretions. The infectiousness of an individual is closely tied to the amount of virus in blood, which is closely associated with HIV levels shed in semen or vaginal fluid or rectal secretions. Although, Highly Active Antiretroviral Therapy (HAART) is associated with complete suppression of HIV RNA in blood to undetectable levels, the impact of HAART on semen HIV RNA levels is less clear. I evaluated the correlation between systemic and mucosal HIV-specific CD8+ T cell immune responses and HIV RNA levels in blood and semen. Overall, there was a strong positive correlation between HIV RNA levels in blood and semen. Neither systemic nor mucosal (in semen) HIV-specific CD8+ responses were associated with HIV RNA levels in blood or semen, in fact CD8+ T cell immune responses in semen correlated with increased HIV RNA levels in semen. Furthermore, inflammatory cytokines (IL-6, and IL-8) CMV levels in semen were associated with increased semen HIV RNA shedding. HAART initiation was associated with complete suppression of HIV viremia, but a significant proportion of individuals on suppressive HAART continue to shed HIV RNA in semen even after 6 months, and this isolated virus was infectious and often present at high levels (> 5000 copies/mL). Nevertheless, long-term HAART was associated with complete immune reconstitution of CD4+ T cells in the sigmoid colon of HIV-infected individuals on long-term therapy. These findings demonstrate that neither systemic nor mucosal HIV-specific CD8+ responses, when assayed with IFN- production as an endpoint, were associated with reduced HIV RNA levels in blood or semen. Semen HIV RNA levels did correlate with local inflammatory cytokines and CMV reactivation. Furthermore, despite effective HAART a significant proportion of HIV-infected men continued to shed HIV RNA in semen. However, long-term completely suppressive HAART was associated with complete immune reconstitution of the sigmoid colon.

HIV infects over 33 million people worldwide with a new infection occurring every 9 seconds. Sex is the primary mode of transmission and the majority of new infections occur during unprotected sexual contact between an HIV-infected individual and an uninfected sexual partner(s) since HIV infected individuals tend to shed virus in their genital secretions. The infectiousness of an individual is closely tied to the amount of virus in blood, which is closely associated with HIV levels shed in semen or vaginal fluid or rectal secretions. Although, Highly Active Antiretroviral Therapy (HAART) is associated with complete suppression of HIV RNA in blood to undetectable levels, the impact of HAART on semen HIV RNA levels is less clear. I evaluated the correlation between systemic and mucosal HIV-specific CD8+ T cell immune responses and HIV RNA levels in blood and semen. Overall, there was a strong positive correlation between HIV RNA levels in blood and semen. Neither systemic nor mucosal (in semen) HIV-specific CD8+ responses were associated with HIV RNA levels in blood or semen, in fact CD8+ T cell immune responses in semen correlated with increased HIV RNA levels in semen. Furthermore, inflammatory cytokines (IL-6, and IL-8) CMV levels in semen were associated with increased semen HIV RNA shedding. HAART initiation was associated with complete suppression of HIV viremia, but a significant proportion of individuals on suppressive HAART continue to shed HIV RNA in semen even after 6 months, and this isolated virus was infectious and often present at high levels (> 5000 copies/mL). Nevertheless, long-term HAART was associated with complete immune reconstitution of CD4+ T cells in the sigmoid colon of HIV-infected individuals on long-term therapy. These findings demonstrate that neither systemic nor mucosal HIV-specific CD8+ responses, when assayed with IFN- production as an endpoint, were associated with reduced HIV RNA levels in blood or semen. Semen HIV RNA levels did correlate with local inflammatory cytokines and CMV reactivation. Furthermore, despite effective HAART a significant proportion of HIV-infected men continued to shed HIV RNA in semen. However, long-term completely suppressive HAART was associated with complete immune reconstitution of the sigmoid colon.

No description available.

Contaminated areas resulting from anthropogenic activities have, for the most part, concentrations of contaminants that exceed Tier 1 standards below which the risk is considered acceptable. However, contaminants that have been in soil for a prolonged period can become recalcitrant over time, due to various physico-chemical and biological processes. Sequestered and recalcitrant contaminants are not readily biologically available to living organisms. However, they are easily measured analytically because of the strong acid extractions that are used in the analytical methodologies. Because toxicity is a function of exposure concentration(s), exposure duration, and bioavailability, contaminants in soil can be present at concentrations that exceed established standards but they represent minimal risk to ecological receptors because the contaminants are not fully available. To predict toxicity and estimate risk, it is imperative that an accurate and reliable measure of bioavailability be available. Several surrogate measures of bioavailability were compared to the results of a battery of toxicity tests using Cu, Pb, and Zn-contaminated soils collected from a former industrial area and Cu and Zn-contaminated soils collected from a former mining site. CaCl₂extractions, hydroxypropyl-β-cyclodextrin (cyclodextrin) extractions, Simulated Earthworm Gut (SEG) tests, and bioaccumulation tests were performed using the soils. Overall, SEG-extractable Cu was most predictive of adverse effects in industrial soils, likely due to enzymatic activity and/or increased ionic strength of the solution. For the mining soils, all chemical measures of bioavailability correlated with several biological responses; however, CaCl₂-extractable Cu and SEG-extractable Cu and Zn best predicted earthworm responses. Total Cu concentrations in soil correlated best with adverse effects to plants. No method was a good predictor of all biological effects for a single organism when data from the two sites were combined. The SEG test may provide a good indication of metal toxicity at contaminated sites with varying soil physico-chemical characteristics but further validation is required.