Ce travail est en relation avec la thématique "Energies Propres". Le diméthoxyméthane estun composé adapté au stockage de l’hydrogène pour des applications mobiles, de par saforte teneur en hydrogène, sa très faible toxicité et son faible impact sur l'environnement.De ce fait, des catalyseurs mixtes, à base d’oxyde de vanadium et d’oxyde de titanesulfatés ont été préparés et testés dans la réaction d'oxydation sélective du méthanol enDMM, en vue de la production d'hydrogène. Les propriétés acides et redox de surface ontété corrélées aux performances catalytiques. Les mécanismes de réaction et l'identificationdes facteurs limitant l'activité et la sélectivité des catalyseurs ont été aussi étudiés. / This work is related to the subject “Clean Energy”. Dimethoxymethane (DMM) is asuitable H2 storage material for mobile application because of its high content of hydrogen,extremely low toxicity and environmentally benign. Therefore, sulfated vanadia-titania,sulfated binary vanadia-based and titania-based catalysts were prepared and evaluated inthe reaction of selective oxidation of methanol to DMM and further production ofhydrogen. The surface acidic and redox properties of the studied catalysts were correlatedto their catalytic performance. In addition, the reaction mechanisms and the identificationof factors limiting the activity and selectivity of catalysts were also studied.

Des catalyseurs à base d'oxyde de manganèse ont été préparés par différentes voies et évalués dans l'Oxydation en Voie Humide Catalytique de l'ammoniaque. Les catalyseurs sont actifs, sélectifs en diazote et stables dans les conditions de la réaction. Diazote et nitrite sont des produits primaires de la réaction. Une étude approfondie de l'effet des paramètres opératoires (teneur en manganèse, pression partielle en oxygène, concentration en ammoniaque, pH initial de la solution, charge de surface du catalyseur) sur les performances catalytiques a été réalisée. La sélectivité en diazote est favorisée lorsque i) la quantité de catalyseur est faible, ii) le rapport nO2/nNH4+ est proche de la stœchiométrie (˜ 0,75) et iii) le pH au point de charge nulle du catalyseur est neutre. Bien qu'un pH fortement basique (pH 13) améliore l'activité catalytique, la conversion nitrite en nitrate est inhibée et la sélectivité en diazote est dégradée. D'un point de vue cinétique, les ordres partiels par rapport à l'oxygène et à l'ammoniaque sont de 0 et 1, respectivement. L'étude de l'influence de l'état d'oxydation du manganèse (+II, +III et +IV), en présence d'oxydes de manganèse massiques commerciaux ou de catalyseurs à base d'oxyde de manganèse supporté sur cérine, montre que le site actif serait constitué d'une paire Mn(+III)/Mn(+IV). La réaction « fait son site » et les oxydes pour lesquels le manganèse est initialement présent à un faible degré d'oxydation se trouvent fortement modifiés en cours de réaction. Une synergie entre le manganèse et le cérium est également confirmé, impliquant les deux couples redox Mn(+III)/Mn(+IV) et Ce(+III)/Ce(+IV) de manière concertée / Manganese oxide-based catalysts have been synthesized through different routes and evaluated in the Catalytic Wet Air Oxidation of ammonia. Such catalysts are active, selective towards molecular nitrogen and stable under the applied reaction conditions. Molecular nitrogen and nitrite are primary products. A detailed study of the impact of the operating conditions (manganese content, oxygen partial pressure, ammonia concentration, initial pH, and charge at the catalyst surface) on the catalytic performances was carried out. The selectivity in molecular nitrogen is optimum when i) the amount of catalyst is low, ii) the ratio nO2:nNH4+ is close to stoichiometry (˜ 0.75) and ii) the pH at the point of zero charge of the catalyst is neutral. Although strongly basic conditions (pH 13) improve the catalytic activity, the conversion nitrite to nitrate is inhibited and the selectivity in molecular nitrogen is degraded. From a kinetic point of view, the reaction order with respect to oxygen and ammonia are 0 and 1, respectively. The influence of the oxidation state of manganese (+II, +III and +IV) in the presence of bulk manganese oxides or ceria-supported manganese oxides indicated that the active site would consist of a pair of Mn(+III) and Mn(+IV). The reaction makes the active site and the oxides where manganese is initially present at a low oxidation state are markedly modified upon reaction. A synergy between manganese and cerium is also confirmed, involving the two Mn(+III)/Mn(+IV) and Ce(+III)/Ce(+IV) redox couples in a concerted way

Mercury (Hg) is a global pollutant and potent neurotoxin that bioaccumulates in aquatic and terrestrial food webs as monomethylmercury (MeHg). Anaerobic microbes are largely responsible for MeHg production, which depends on the bioavailability of inorganic Hg substrates to methylators. Hg redox cycling pathways such as Hg reduction play a key role in determining Hg’s availability in the environment. Although abiotic photochemical Hg reduction typically dominates in oxic surface environments, Hg reduction pathways mediated by photosynthetic and anaerobic microbes are thought to play an important role in anoxic habitats where light is limited and MeHg production occurs. Currently, the physiological mechanisms driving phototrophic and anaerobic Hg reduction remain poorly understood. The main objective of my thesis is to provide mechanistic details on novel anaerobic and phototrophic Hg reduction pathways. I used a combination of physiological, biochemical and trace Hg analytical techniques to study Hg reduction pathways in a variety of anaerobic and photosynthetic bacteria. I demonstrated that Hg redox cycling was directly coupled to anoxygenic photosynthesis in aquatic purple non-sulphur bacteria that reduced HgII when cells incurred a redox imbalance. I discovered that terrestrial fermentative bacteria reduced Hg through pathways that relied on the generation of reduced redox cofactors. I also showed that sulphur assimilation controlled Hg reduction in an anoxygenic phototroph isolated from a rice paddy. In addition, I developed methods to explore cryptic anaerobic Hg redox cycling pathways using Hg stable isotope fractionation. At its core, my thesis underscores the intimate relationship between cell redox state and microbial Hg reduction and suggests a wide diversity of microbes can participate in anaerobic Hg redox cycling.

Changes in lifestyle of people has been dynamically observed in recent decades, emphasis is given to dietary issues. In this case, as directly responsible for chronic diseases, along with other aspects of lifestyle such as inactivity, smoking, quality of life. In the context of chronic diseases of high incidence and prevalence, the metabolic syndrome has gained prominence in clinical and experimental research in the search for early diagnostic methods for its various components such as the vascular, biochemical and liver, all also associated with diet. In this context, there was the inclusion of non-alcoholic fatty liver disease as liver component of the metabolic syndrome, which is the central object of this work. Objective: To evaluate the profile morphological, functional and redox balance in the liver of a novel induced-diet mice model for metabolic syndrome. Methods: Eleven isogenic male C57BL/6J mice were randomly divided into control (CT) and hypercaloric (HC) groups and fed with chow and hypercaloric diet, respectively, for 26 weeks. We did ratings serum markers of liver function (ALT, AST, ALP, γ-GT, LDH, albumin and total protein), analysis of local redox status (SOD, CAT and lipid peroxidation) and histological study of tissue. Results: There were significant elevations of the statistical point of view in the main markers of liver function in HC animals. This increase was approximately 1.5 times for ALT, 2.5 for AST and 7.4 for ALP. The activity of γ-GT followed the pattern of significant increase in the HC group, despite its low activity. There re no differences in the concentrations of albumin and total protein. On the local redox state, the activity of SOD was not different between groups, the catalase activity was significantly decreased in HC group and there re high levels of peroxidation in this same group. The histological findings corroborate these results, which corresponds to advanced liver disease in animals HC (default cirrhotic). Conclusion: The hepatic component in the novel induced-diet mice model for metabolic syndrome shows changes in your profile functional, redox balance and morphological. Keywords: Metabolic Syndrome, Liver Functions, Redox Balance, Novel Diet-induced Mice Model. / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / As alterações no estilo de vida das pessoas vem sendo dinamicamente observadas nas últimas décadas; destaque especial é dado aos aspectos dietéticos. Neste caso, como responsável direto por doenças crônicas, juntamente com outros aspectos do estilo de vida como sedentarismo, tabagismo, qualidade de vida. No contexto das doenças crônicas de elevada incidência e prevalência, a síndrome metabólica vem ganhando destaque nas pesquisas experimentais e clínicas na busca de métodos diagnósticos precoces para seus vários componentes a exemplo dos vasculares, bioquímicos e hepáticos, todos com associação também dietética. Neste contexto, destaca-se a inserção das doenças hepáticas gordurosas não alcoólicas como componente hepático da síndrome, sendo este o objeto central do presente trabalho. Objetivo: Avaliar o perfil morfológico, funcional e o balanço redox do fígado de um novo modelo murino dietético para síndrome metabólica. Métodos: Onze camundongos isogênicos machos C57BL/6J foram randomicamente divididos nos grupos Controle (CT) e Hipercalórico (HC) e alimentados com dieta chow e hipercalórica, respectivamente, durante 26 semanas. Foram procedidas avaliações plasmáticas de marcadores de função hepática (ALT, AST, ALP, γ-GT, LDH, albumina e proteínas totais), análise do estado redox local (SOD, CAT e peroxidação lipídica) e estudo histológico do tecido. Resultados: Foram encontradas elevações significativas do ponto de vista estatístico nos principais marcadores de função hepática nos animais HC. Esse aumento foi de aproximadamente 1,5 vezes para ALT, 2,5 para AST e de 7,4 para ALP. A atividade de γ-GT seguiu o padrão observado de elevação significativa no grupo HC, apesar de sua baixa atividade. Não foram observadas diferenças nas concentrações de albumina e proteínas totais. Relativo ao estado redox local, a atividade de SOD não foi diferente entre os grupos, a de catalase foi significativamente diminuída nos HC e os níveis de peroxidação elevados. Os achados histológicos corroboram esses resultados, sendo corresponde a doença hepática avançada nos animais HC (padrão cirrótico). Conclusão: O componente hepático no novo modelo murino dietético para síndrome metabólica estudado apresenta alterações em seu perfil morfológico, funcional e no balanço redox.

Introduction: Diabetes is characterized by insufficient production of insulin and/or incapacity of this hormone in playing its functions. Such disease impairs the function of the endothelium, the latter capable of regulating the vascular tone and important in the control of inflammatory response as well. Once dysfunctional, the endothelium no longer exhibits such functions, occurring mostly redox imbalance, this one evident in diabetic patients. Nowadays, several studies point to endothelial dysfunction as a contributor in the development of diabetic vascular complications, while the practice of physical activity, although of low intensity, brings benefits in the handling of type 2 diabetes, including reduction of cardiovascular risk factors. Physical intervention as a therapeutic proposal appears to be a promising way in the clinical management of diabetes mellitus, probably avoiding the progression of systemic complications. Aim: To assess the vascular function and the REDOX balance in patients with type 2 diabetes mellitus (T2DM) before and after the cardiovascular rehabilitation for six weeks. Methods: 43 diabetic female patients aged 57.50 ± 2.02 years were selected from the ambulatory of Endocrinology at Prof. Alberto Antunes Teaching Hospital (Federal University of Alagoas). The diagnosis for T2DM was established according to the criteria of the Brazilian Society of Diabetes (2007). Initial assessment was performed by laboratory and clinical evaluation. The cardiovascular rehabilitation program consisted of six weeks of aerobic training (50 to 70% of the maximum heart rate), associated to endurance training. Four patients have completed the six weeks rehabilitation program. Assessment of biochemical profile (fasting and postprandial glucose, glicosilated hemoglobin, total cholesterol, VLDL, LDL, HDL, triglycerides, uric acid, albumin and creatinin), REDOX balance (SOD and catalase activity and lipid peroxidation) and quality of life (through the application of the SF-36) were performed before and after the rehabilitation program period. Indirect assessment of vascular function was performed by the Augmentation Index (AI), wave reflection, systolic and diastolic blood pressure and pulse pressure, which were obtained by the left radial artery tonometry (HEM-9000 AI device). Physical capacity was assessed by the six-minute walk test. Results: After rehabilitation, there was a significant reduction in the serum albumin levels (3.52 ± 0.478 vs 3.85 ± 0.50 mg/dL, P=0.0159) and an increase in the serum acid uric levels (5.00 ± 0.25 vs 4.57 ± 0.21 mg/dL, P=0.0298), without, however, alterations in the creatinin levels (P=0.3760). It was observed a reduction in the systolic and diastolic blood pressure (141.50 ± 3.67 vs 117.00 ± 6.01 mmHg, p<0.01; 77.75 ± 1.48 vs 71.25 ± 3.03 mmHg, P<0.05, respectively) and in the pulse pressure (63.75 ± 2.29 vs 45.750 ± 3.68 mmHg, P<0.01), without improvement in the Augmentation Index, with an improvement in five parameters during the assessment of the quality of life: physical functioning (25.00 ± 17.56 vs 93.75 ± 6.25 %, P<0.05), vitality (31.250 ± 10.48 vs 87.50 ± 5.20 %, P<0.05), social functioning (50.00 ± 17.68 vs 100.00 ± 0.00 %, P<0.05), role physical (47.50 ± 8.53 vs 92.50 ± 3.22 %, P<0.01) and bodily pain (21.62 ± 10.68 vs 65.75± 12.49 %, P<0.01). There were no statistically significant changes neither in the glycemic and lipid profiles nor in the functional capacity. Conclusion: The cardiovascular rehabilitation program during six weeks in diabetic patients was capable of promoting improvement in hemodynamic parametres and in the quality of life, without greater changes in the biochemical profile and functional capacity. These observations permit to consider that in diabetic patients the cardiovascular rehabilitation should be initiated as soon as possible to promote a reduction in the cardiovascular risk in these individuals. / Introdução: O diabetes caracteriza-se pela produção insuficiente de insulina e/ou pela incapacidade desse hormônio em desempenhar suas funções. Tal doença prejudica a função do endotélio, tecido este capaz de regular o tônus vascular e a resposta inflamatória. Quando disfuncional, esta camada celular não mais exibe tais funções, ocorrendo, principalmente, o desbalanço redox, evidente em pacientes diabéticos. Atualmente, diversos estudos apontam para a disfunção endotelial como contribuinte para o desenvolvimento das complicações vasculares diabéticas, ao passo que a prática de atividade física, ainda que de baixa intensidade, traz benefícios no manejo do diabetes mellitus tipo 2, incluindo redução dos fatores de risco cardiovascular. Desta forma, a intervenção física como proposta terapêutica apresenta-se promissora no manejo clinico do diabetes mellitus, podendo evitar a progressão de complicações sistêmicas. Objetivo: Avaliar a função vascular e o balanço redox em pacientes portadores de diabetes mellitus tipo 2 (DMII), antes e após a reabilitação cardiovascular por seis semanas. Método: 43 pacientes do sexo feminino com idade média de 57,50 ± 2,02 foram selecionadas do ambulatório de Endocrinologia do Hospital Universitário Prof. Alberto Antunes (Universidade Federal de Alagoas). O diagnóstico de DMII foi estabelecido de acordo com os critérios da Sociedade Brasileira de Diabetes (2007). A avaliação inicial foi feita através de exames clínicos e laboratoriais. O programa de reabilitação cardiovascular consistiu de seis semanas de exercício aeróbio (50 a 70% da freqüência cardíaca máxima) associado a exercícios resistidos. Quatro pacientes completaram as seis semanas de reabilitação. Avaliação do perfil bioquímico (glicemia de jejum e pós-prandial, hemoglobina glicosilada, colesterol total, VLDL, LDL, HDL, triglicerídeos, ácido úrico, albumina e creatinina), balanço REDOX (atividades da SOD e catalase e peroxidação lipídica) e qualidade de vida (através da aplicação do SF-36) foram realizadas antes e após o programa de reabilitação. A avaliação indireta da função vascular foi realizada através do Augmentation Index (AI), onda de reflexão, pressões arteriais sistólica e diastólica e pressão de pulso, obtidos por tonometria da artéria radial esquerda (com o equipamento HEM-9000 AI). A capacidade física foi avaliada através do teste de caminhada de seis minutos. Resultados: Após a reabilitação, houve redução significativa dos níveis séricos albumina (3,52 ± 0,478 vs 3,85 ± 0,50 mg/dL, P=0,0159) e aumento dos níveis de ácido úrico (5,00 ± 0,25 vs 4,57 ± 0,21 mg/dL, P=0,0298), sem, entretanto, alterações dos níveis de creatinina (p=0,3760). Também foram reduzidas as pressões arteriais sistêmicas sistólica e diastólica (141,50 ± 3,67 vs 117,00 ± 6,01 mmHg, P<0,01; 77,75 ± 1,48 vs 71,25 ± 3,03 mmHg, P<0,05, respectivamente) e a pressão de pulso (63,75 ± 2,29 vs 45,750 ± 3,68 mmHg, P<0,01), sem redução no Augmentation Index, com melhora em cinco parâmetros da qualidade de vida: aspectos físicos (25,00 ± 17,56 vs 93,75 ± 6,25 %, P<0,05), vitalidade (31,250 ± 10,48 vs 87,50 ± 5,20 %, P<0,05), aspectos sociais (50,00 ± 17,68 vs 100,00 ± 0,00 %, P<0,05), capacidade funcional (47,50 ± 8,53 vs 92,50 ± 3,22 %, P<0,01) e dor (21,62 ± 10,68 vs 65,75 ± 12,49 %, P<0,01). Não foram observadas variações estatisticamente significativas para o perfil glicêmico, lipídico e capacidade funcional. Conclusão: O programa de reabilitação cardiovascular por seis semanas em pacientes diabéticas foi capaz de promover melhora em parâmetros hemodinâmicos e na qualidade de vida, sem maiores mudanças no perfil bioquímico e capacidade funcional. Estas observações permitem considerar que em pacientes diabéticos a reabilitação cardiovascular deve ser iniciada o mais precoce possível a fim de promover redução do risco cardiovascular nestes indivíduos.

The non-alcoholic fat liver diseases (NAFLD) have been presented, recently, as a novel component of the Metabolic Syndrome (MetS), representing the oxidative stress a critical role in their progression. In this context, the present study aimed to assess the morphofunctional hepatic alterations and the redox balance in a murine model for the MetS induced by a high calorie diet, after treatment with tempol and apocinina. C57Bl/6 male mice, young (6-8 weeks) and elderly (53-57 weeks), were divided in four groups: control group (CT; n young=8 and n elderly=5), fed with chow diet (14% calories from lipids); DHC group ( n young=9 and n elderly=5), receiving hypercaloric diet for 14 weeks (58,4% calories from lipids); DHC + Tempol group ( n young=4 and n elderly=9), which received hypercaloric diet and treatment with tempol (50mg/kg) in the water for drinking; DHC + Apocinin group ( n young=4 and n elderly=9), fed with a hypercaloric diet and under apocinin treatment (50mg/kg) in the water for drinking. Metabolic and the redox state assessment, as well as the histological analyses were performed. After the end of the experimental period, young DHC animals were not shown to present significant weight gain, being the latter observed in the elderly DHC animals, when compared to CT group. The treatment with tempol and apocinin was not effective in modifying this parameter in both groups. The DHC animals, both young and elderly, showed fasting hyperglicaemia, and the treatment with tempol and apocinin did not change this profile. A significant improvement in the glucose tolerance was observed in the young animals after the treatment with apocinin, but the treatment with tempol failed to show so. In the elderly animals, a significant improvement in the glucose tolerance and insulin sensitivity was identified after the treatment with tempol and apocinin. An elevated accumulation of visceral fat was identified in the DHC animals (young and elderly), so that the treatment with tempol and apocinin did not alter this profile. An elevated serum concentration of total cholesterol was shown in the young and elderly DHC animals when compared to the CT group, the same not happening to triglycerides, VLDL and lipid peroxidation in both groups, young and elderly. The pharmacological treatment was not shown to be effective in altering these serum parameters. In the young DHC animals, it was not observed significant changes in the enzymatic activities of the AST and ALT, as well as AST/ALT ratio, ALP, &#947;-GT, LDH, albumin and total proteins, when compared to the CT group. However, in the DHC elderly animals, and increased AST activity and AST/ALT ratio were observed among these parameters of hepatic assessment. The DHC animals, young and elderly, presented elevated lipid peroxidation and fat liver accumulation, with numerous fat vacuoles at histology. The pharmacological treatment with tempol and apocinin ameliorated, in a qualitative manner, the fat accumulation in the liver, both in the young and elderly animals, without, however, modifying the hepatic lipid peroxidation. Furthermore, the DHC elderly animals presented high hepatic levels of total lipids, triglycerides, total cholesterol and VLDL cholesterol, with a similar condition not being observed in the DHC young animals. The hepatic activity of the antioxidant enzymes (SOD and CAT) was not shown to be significantly different after the dietary and pharmacological treatments. An increase in the NADPH oxidase activity, and consequently the increased production of superoxide anion ( O2-), may be involved in the mechanisms associated to the MetS and the NAFLD. / Conselho Nacional de Desenvolvimento Científico e Tecnológico / As doenças hepáticas gordurosas não-alcoólicas (DHGNA) foram apresentadas, recentemente, como um novo componente da Síndrome Metabólica (SMet), desempenhando o estresse oxidativo papel fundamental na progressão destas. Nesse contexto, o presente estudo objetivou avaliar as alterações morfo-funcionais hepáticas e do balanço redox em um modelo murino para a SMet induzida por uma dieta hipercalórica, após tratamentos com tempol e apocinina. Camundongos machos C57Bl/6, jovens (6-8 semanas) e idosos (53-57 semanas), foram divididos em quatro grupos: grupo controle (CT; n jovem=8 e n idoso=5), alimentado com dieta chow (14% calorias provenientes dos lipídios); grupo DHC ( n jovem=9 e n idoso=5), que recebeu dieta hipercalórica por 14 semanas (58,4% calorias provenientes dos lipídios); grupo DHC + Tempol ( n jovem=4 e n idoso=9), que recebeu dieta hipercalórica e tratamento com tempol (50mg/kg) na água de beber; grupo DHC + Apocinina ( n jovem=4 e n idoso=9), alimentado com dieta hipercalórica e tratado com apocinina (50mg/kg) na água de beber. Avaliações metabólicas, do estado redox e análise histológica hepática foram realizadas. Após o término do período experimental, os animais DHC jovens não apresentaram significativo ganho de peso corporal, sendo este observado nos animais DHC idosos quando comparados ao grupo CT. O tratamento com tempol e apocinina não modificou este parâmetro em ambos os grupos. Os animais DHC, tanto jovens quanto idosos, apresentaram hiperglicemia de jejum e o tratamento com tempol e apocinina não modificou este perfil. Uma significante melhora na tolerância à glicose dos animais jovens foi observada após o tratamento com a apocinina, o mesmo não ocorrendo após o tratamento com o tempol. Nos animais idosos, uma melhora significativa foi observada na tolerância à glicose e sensibilidade à insulina após o tratamento com tempol e apocinina. Acentuado acúmulo de gordura visceral foi identificado nos animais DHC (jovens e idosos), de modo que o tratamento com o tempol e a apocinina não alterou este perfil. Elevada concentração plasmática de colesterol total foi observada nos animais DHC jovens e idosos comparado ao CT, o mesmo não ocorrendo para triglicerídeos, VLDL e peroxidação lipídica plasmática em ambos grupos DHC, jovens e idosos. O tratamento farmacológico em questão não modificou estes parâmetros plasmáticos. Nos animais DHC jovens, não foram observadas mudanças significativas na atividade das enzimas AST, ALT, razão AST/ALT, ALP, &#947;-GT, LDH, albumina e proteínas totais, quando comparado ao grupo CT. Contudo, nos animais idosos DHC, elevada atividade da AST e da razão AST/ALT foram observadas dentre estes parâmetros de avaliação hepática. Os animais DHC, jovens e idosos, apresentaram elevada peroxidação lipídica e acúmulo de gordura hepática, com numerosos vacúolos gordurosos à histologia. O tratamento farmacológico com tempol e apocinina melhorou, de forma qualitativa, o acúmulo de gordura hepática, tanto nos animais jovens quanto nos idosos, sem, entretanto, modificar a peroxidação lipídica hepática. Além disso, os animais idosos DHC apresentaram elevados níveis hepáticos de lipídios totais, triglicerídeos, colesterol total e VLDL colesterol, não sendo observado o mesmo nos animais jovens DHC. A atividade hepática das enzimas antioxidantes (SOD e CAT) não diferiu significativamente após os tratamentos dietético e farmacológico. O aumento na atividade da NADPH oxidase, e consequentemente a produção de anion superóxido ( O2-), pode estar envolvida nos mecanismos associados à SMet e às DHGNA.

Le paludisme est une maladie parasitaire tropicale menaçant les populations dans les zones tropicales et sub-tropicales, en particulier les jeunes enfants en Afrique. En raison des résistances aux médicaments antipaludiques qui se sont propagées dans le monde entier au cours des 50 dernières années, de nouveaux médicaments sont vraiment nécessaires. La plasmodione (série benzylmenadione) a été identifiée comme un médicament-candidat antipaludique puissant, agissant selon une bioactivation rédox sur les stades sanguins asexués et sexués jeunes, mais son métabolisme est inconnu. Par conséquent, afin d'identifier les structures des métabolites actifs générés par la plasmodione antipaludique, la synthèse complète de la plasmodione 13C18-enrichie a été conçue et réalisée en 10 étapes. En outre, le procédé d'extraction pour l'étude du métabolisme de la molécule a été établi à partir de globules rouges parasités traités par la plasmodione 13C18-enrichie. D'autre part, la préparation de dérivés oxétane et N-alkylaryl de plasmodione avec une solubilité potentielle améliorée a également été réalisée par substitution nucléophilie aromatique (SNAr) et réaction de couplage Buchwald-Hartwig catalysée par le palladium, respectivement. Enfin, un complexe d'or (I) phosphole, connu comme un inhibiteur irréversible et puissant de la thiorédoxine réductase séléno-dépendante humaine, a été synthétisé et son profil antiparasitaire a été étudié sur de nombreux parasites pathogènes pour l’homme, protozoaires et helminthes en cultures. / Malaria is a tropical parasitic disease threatening populations in tropical and sub-tropical areas, especially young children in Africa. Due to the drug resistance spread all over the world in the past 50 years, new drugs are urgently needed. Plasmodione (benzylmenadione series) had been identified as a potent anti-malarial early lead drug, acting through a redox bioactivation on asexual and young sexual blood stages, but its drug metabolism is unknown. Therefore, in order to identify the structures of the active drug metabolites generated from the antimalarial plasmodione, fully 13C18-enriched-plasmodione synthesis was designed and performed in 10 steps. Furthermore, the extraction method for the drug metabolism study was established from 13C18-enriched plasmodione-treated parasitized red blood cells. On the other hand, the preparation of oxetane and N-alkylaryl derivatives of plasmodione with potential improved solubility was also investigated through aromatic nucleophilic substitution (SNAr) and palladium-catalyzed Buchwald-Hartwig coupling reaction, respectively. Finally, a gold(I) phosphole complex, known as an irreversible and potent inhibitor of the human seleno-dependent thioredoxin reductase, was synthetized and its antiparasitic profile investigated against a panel of parasites, protozoans and helminthes in cultures.

Les radicaux organiques tiennent une place de choix dans de nombreux domaines et il est établi que ceux-ci peuvent exister coordinés à des centres métalliques dans les métalloenzymes. La Galactose Oxydase par exemple contient une entité cuivre(II)-radical phénoxyle indispensable à sa réactivité pour l'oxydation aérobie d'alcools en aldéhydes. Ces travaux de thèse ont consisté en l'élaboration de complexes de métaux de transitions (cuivre, nickel, cobalt) à partir de ligands noninnocents. Les caractérisations des espèces sous divers degrés d'oxydation ont été réalisées par différentes techniques complémentaires d'analyse (l'électrochimie, la RPE, l'UV-visible-proche-IR, la resonance raman ainsi que la diffraction des rayons X) combinées à des études de chimie théorique. Nous avons synthétisé des complexes Ni(II)-salen symétriques et dissymétriques et montré que l'espèce oxydée radicalaire pouvait acquérir un caractère localisé (composé de classe II) ou délocalisé (composé de classe III selon Robin-Day) en fonction des substituants phénoliques. Dans des complexes Cu(II)-salophen nous avons mis en évidence une activité redox centrée sur le pont, conduisant à des espèces Cu(II)-radicaux π diaminobenzène. Dans le cas des complexes de cobalt, les orbitales redox actives du métal et du ligand sont si proches en énergie que l'espèce oxydée est un hybride de résonance entre les formes Co(III)-phénolate et Co(II)-phénoxyle. Nous avons évalué l'influence du remplacement des oxygènes du salen par des azotes sur la structure électronique des espèces oxydées. Enfin, des complexes ont été mis au point à partir d'un ligand bis(phénol)-dipyrrine et les espèces oxydées radicalaires ont été caractérisées structuralement. Elles ont un caractère mixte porphyrinyle-phénoxyle jamais mis en évidence au préalable. / Organic radicals play key roles in various fields and it is established that they could coordinate metal centers in metalloenzymes. For example, Galactose Oxydase exhibits a copper-phenoxyl entity, essential for its reactivity (aerobic oxidation of alcohols to aldehydes). This thesis is focused on the design of transition metal complexes (copper, nickel, cobalt) from non innocent ligands. The characterization of species at various oxidation states has been performed by complementary analytical techniques (electrochemistry, EPR, UV-vis-NIR, raman resonance, X-ray crystallography) and theoretical chemistry. Several Ni-salen complexes were synthetized (symmetrical or not) and the resulting oxidized species could be either localized (class II compound) or delocalized (class III compound) radicals depending on the phenolic substituents. In Cu(II)-salophen complexes we successfully shed light on a bridge-centered redox activity, leading to Cu(II)-diaminobenzene π radical species. In the case of cobalt, both metal and ligand redox active orbitals are isoenergetic and the oxidized species is a resonance hybrid between the Co(III)-phenolate and the Co(II)-phenoxyl forms. We evaluated the influence of the replacement of the salen oxygen atoms by nitrogen ones on the electronic structure of the resulting oxidized species. Finally, original complexes were synthesized from a bis(phénol)-dipyrrine ligand and the radical oxidized species were structurally characterized. They exhibit a unprecedented mixed porphyrinyl-phenoxyl character.

Mutations in the AAAS gene coding for the nuclear pore complex protein ALADIN lead to the autosomal recessive disorder triple A syndrome. Triple A patients present with a characteristic phenotype including alacrima, achalasia and adrenal insufficiency. Patient fibroblasts show increased levels of oxidative stress, and several in vitro studies have demonstrated that the nucleoporin ALADIN is involved in both the cellular oxidative stress response and adrenal steroidogenesis. It is known that ALADIN knock-out mice lack a phenotype resembling human triple A syndrome. The objective of this study was to determine whether the application of chronic oxidative stress by ingestion of paraquat would generate a triple A-like phenotype in ALADIN null mice. Adult male mice were fed either a paraquat (0.25 g/kg diet) or control diet for 11 days. After application of chronic oxidative stress, ALADIN knock-out mice presented with an unexpected compensated glutathione metabolism, but lacked a phenotype resembling human triple A syndrome. We did not observe increased levels of oxidative stress and alterations in adrenal steroidogenesis in mice depleted for ALADIN. This study stresses the species-specific role of the nucleoporin ALADIN, which in mice involves a novel compensatory mechanism for regulating the cellular glutathione redox response.

Made available in DSpace on 2016-06-02T19:30:12Z (GMT). No. of bitstreams: 1 6741.pdf: 15167648 bytes, checksum: a9c6d1fafc3e61950d1dbffe3c66e1bf (MD5) Previous issue date: 2015-02-25 / Universidade Federal de Sao Carlos / The estuarine regions are distributed along the coasts worldwide and show gradients of environmental conditions. Flooding and salinity are often considered the most important factors to influence plant species distribution in estuarine communities. Nevertheless, other factors such as geographic localization, geomorphological formation and variations of the flooding cycles may influence plant community s organization. Some studies also indicate expressive differences in species distribution patterns between temperate and tropical estuaries. Functional diversity may support the understanding of diversity patterns through the distribution and composition of functional traits in plant communities and help us understand the differences among distinct estuaries. Functional traits may be directly measured from plant individuals or determined as categories for each species (or group of species) and must be related to relevant processes in the community. Using the information of functional traits and species composition (or abundance) in each community, we may calculate functional diversity indices and then evaluate its variation patterns along the estuarine gradients. In chapter 1 of this thesis, we investigated the variations of plant functional diversity in three salt marshes of the west coast of England. In salt marshes, soil redox potential water content and the relative tide height are important factors to determine the colonization and species diversity of plant communities. Our results showed that plant functional diversity increased along the flooding gradient and that soil redox potential and relative tide height were the main factors to influence the variation of functional diversity. In chapter 2, we investigated plant functional diversity of two estuaries with distinct flooding cycles (open and closed) in the coast of São Paulo State. We observed that functional diversity varied mainly along the flooding gradient, increasing at higher elevations at both estuaries. Salinity was also important to functional diversity in the open estuary. We also observed functional diversity indices showed higher values at closed estuary. This result might be related to the longer and less predictable flooding cycle in the closed estuary, which generates a less sharp pattern of species distribution, so traits combination and functional diversity are higher. The factor considered important filters for species distribution are also major determinants of plant functional diversity in estuarine communities. Nevertheless, the investigation of functional diversity patterns helps us identify and discuss how the effect of different flooding cycles on estuarine communities. / As regiões estuarinas estão distribuídas ao longo da costa de todo o mundo e apresentam condições ambientais distribuídas em gradientes. O alagamento e a salinidade são considerados os mais importantes fatores a influenciar a distribuição de espécies das comunidades vegetais estuarinas. No entanto, outros fatores como a localização geográfica, a formação geomorfológica e variações nos ciclos de alagamento influenciam a organização das formações vegetais. Alguns estudos apontam também para diferenças expressivas nos padrões de distribuição entre estuários de áreas temperadas e tropicais. A diversidade funcional pode contribuir na compreensão dos padrões de diversidade através da distribuição e composição de traços funcionais das plantas da comunidade e nos ajudar a entender as diferenças existentes entre estuários distintos. Os traços funcionais podem ser medidos diretamente nos indivíduos ou determinados categoricamente para cada espécie (ou grupo de espécies) e devem ser relacionados a processos relevantes na comunidade e às questões de estudo. A partir das informações sobre os traços funcionais e a composição (ou abundância) de suas espécies, podemos calcular os índices de diversidade funcional e, então, avaliar seus padrões de variação ao longo dos gradientes ambientais estuarinos. No capítulo 1, investigamos a diversidade funcional em três marismas da costa leste da Inglaterra. Nos marismas, o potencial redox, a quantidade de água e a altura relativa da maré são fatores importantes para determinar a colonização e a diversidade de espécies da comunidade vegetal. Nossos resultados indicaram que a diversidade funcional da comunidade aumentou em relação ao gradiente de alagamento e que o potencial redox e a altra relativa da maré foram os principais fatores medidos a influenciar a variação da diversidade funcional. No capítulo 2, investigamos a diversidade funcional de dois estuários com ciclos de alagamento distintos (aberto e fechado) no litoral do estado de São Paulo. Observamos que a diversidade funcional variou principalmente em relação ao gradiente de alagamento, aumentando em elevações mais altas nos dois estuários. A salinidade foi também importante 27! para a diversidade funcional no estuário aberto. Observamos também os índices de diversidade funcional atingem valores maiores no estuário fechado. Este resultado deve ser devido ao ciclo de alagamento mais longo e menos previsível do estuário fechado, que gera um padrão de distribuição de espécies menos claro, de forma que a combinação de traços e, consequentemente, a diversidade funcional sejam maiores. Os fatores considerados importantes filtros da distribuição de espécies também são significativamente determinantes da diversidade funcional de comunidade vegetais estuarinas. No entanto, a investigação da diversidade funcional permite identificar e discutir como as variáveis afetam as comunidades estuarinas de forma mais detalhada, permitindo entender a influência dos diferentes ciclos de alagamento sobre estas comunidades.