Submitted by Rosivalda Pereira (mrs.pereira@ufma.br) on 2017-05-05T19:27:14Z No. of bitstreams: 1 AdrianoPereira.pdf: 4552452 bytes, checksum: c5dc1a24e3fc6e843a7a494ecc39cb39 (MD5) / Made available in DSpace on 2017-05-05T19:27:14Z (GMT). No. of bitstreams: 1 AdrianoPereira.pdf: 4552452 bytes, checksum: c5dc1a24e3fc6e843a7a494ecc39cb39 (MD5) Previous issue date: 2016-07-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPQ) / Fundação de Amparo à Pesquisa e ao Desenvolvimento Científico e Tecnológico do Maranhão (FAPEMA) / Materials consisting of amino acids are of great interest in the application in nonlinear optical (NLO) and are being studied more carefully because they have properties better than the potassium dihydrogen phosphate (KDP), the material most commonly used for Second Generation Harmonic (SHG). In this work, the crystals of L-arginine hydrobromidric monohydrate (LAHBr) and L-arginine hydrochloridric monohydrate (LAHCl) were grown at room temperature (25° C) by the method of slow evaporation of solvent. Were also synthesized hydrochlorobromidric L-arginine monohydrate crystals (LAHClBr) from the mixture of the compounds in equimolar proportions 1:3, 1:1 and 3:1. These five crystals were characterized by the techniques of X-Ray Fluorescence (XRF), Diffraction X-Ray (XRD), Raman Spectroscopy, Thermogravimetry (TG), Differential Thermal Analysis (DTA) and Differential Scanning Calorimetry (DSC). The chemical composition of the single crystal was analyzed by X-ray Fluorescence (XRF) and compositions obtained were: C6H14N4O2•HCL0.14BR0.86•H2O (LAHCl0,14Br0,86), C6H14N4 O2•HCL0.42BR0.58•H2O (LAHCl0,42Br0,58), e C6H14N4O2•HCL0.63BR0.37•H2O (LAHCl0,63Br0,37). The structural parameters of the crystals were characterized by X-ray diffraction (XRD) in association with the Rietveld refinement. The all samples crystallize with the monoclinic structure (space group P21) and the unit cell volume of LAHClxBr1-x series decreases with increasing concentration of chlorine in the composition of the samples. The vibrational modes were observed by Raman Spectroscopy. The Raman spectrum experiments have shown that bands associated with lattice modes undergo blue shifts as the concentration of chorine ion is increased in addition to complement the results obtained by XRD technique. The thermal analysis of TG, DTA and DSC showed that the crystals analyzed show a decrease in temperature of the characteristic exothermic phase transition event, as well as increasing in the melting temperature of the material, with increasing chlorine concentration. The crystals LAHBr, LAHClBr and LAHCl to lose water of hydration suffer phase transformation goes to anhydrous phase without change in structure (monoclinic-monoclinic) and present structural phase transition around 150 oC. / Materiais constituídos por aminoácidos são de grande interesse na aplicação em óptica nãolinear (NLO) e estão sendo estudados com maior atenção por apresentarem propriedades melhores do que o material mais utilizado para Geração de Segundo Harmônico (SHG); dihidrogenofosfato de potássio (KDP). Neste trabalho os monocristais de L-arginina hidrobromídrica monohidratada (LAHBr) e L-arginina hidroclorídrica monohidratada (LAHCl) foram crescidos à temperatura ambiente (25°C), pelo método de evaporação lenta do solvente. Também foram sintetizados cristais de L-arginina hidroclorobromídrica monohidratada (LAHClBr), a partir da mistura dos dois compostos, nas proporções molares 1:3, 1:1 e 3:1. Esses cinco cristais foram caracterizados pelas técnicas de Fluorescência de raios-X (FRX), Difração de raios-X (DRX), Espectroscopia Raman, Termogravimetria (TG), Análise Diferencial Térmica (DTA) e Calorimetria Exploratória Diferencial (DSC). A composição química dos monocristais foi analisada por FRX e as composições são: C6H14N4O2•HCL0.14BR0.86•H2O (LAHCl0,14Br0,86), C6H14N4O2•HCL0.42BR0.58•H2O (LAHCl0,42Br0,58), e H14N4O2•HCL0.63BR0.37•H2O (LAHCl0,63Br0,37), para as amostras de LAHClBr 1:3, LAHClBr 1:1 e LAHClBr 3:1, respectivamente. Os parâmetros estruturais dos cristais foram caracterizados por DRX em associação com o refinamento de Rietveld, onde observamos que todas as amostras se cristalizam com a estrutura monoclínica (grupo espacial P21) e que o volume da célula unitária da série LAHClxBr1-x diminue com o aumento da concentração de Cloro na composição das amostras. Os modos vibracionais foram observados por Espectroscopia Raman. Os espectros Raman mostraram que as bandas associadas aos modos de rede sofreram blue shifts com o aumento da concentração de Cl, além de complementar os resultados obtidos pela técnica de DRX. As análises térmicas de TG, DTA e DSC mostraram que os cristais analisados apresentaram uma diminuição de temperatura do evento exotérmico característico de transição de fase com o aumento da concentração de Cl, bem como, aumento da temperatura em que ocorre a fusão do material. Os cristais de LAHBr, LAHClBr e LAHCl ao perderem água de hidratação sofrem transformação de fase indo para a fase anidra sem mudança na estrutura cristalina monoclínicamonoclínica) e apresentam uma transição de fase estrutural em torno de 150 oC.

<p>Lichens are fascinating symbiotic systems, where a fungus and a unicellular alga, most often green (bipartite green algal lichens; 90% of all lichens), or a fi lamentous cyanobacterium (bipartite cyanobacterial lichens; 10% of all lichens) form a new entity (a thallus) appearing as a new and integrated organism: in about 500 lichens the fungus is associated with both a cyanobacterium and an alga (tripartite lichens). In the thallus, the lichen bionts function both as individual organisms, and as a symbiont partner. Hence, in lichens, the participating partners must both be able to receive and acquire resources from the other partner(s) in a controlled way.</p><p>Lichens are particularly successful in harsh terrestrial environments. In part this is related to their poikilohydric nature and subsequent ability to repeatedly become desiccated and hydrated. Metabolic activity, i.e. photosynthesis, respiration, and for cyanobacterial lichens N2-fixation, is limited to periods when the thallus is suffi ciently hydrated. Mineral nutrients are mainly acquired from dry or wet deposition directly on the thallus. Taken together it then appears that lichens are to a large extent passively controlled by their environment, making their control over resource allocation and acquisition particularly challenging.</p><p>The aim of this thesis was to investigate resource acquisition and allocation processes in different lichens, and to see how these respond to changes in resource availability. This was done by following lichen growth in the fi eld during manipulation of water, light, and nutrient supply, and by assessing the responses of both the integrated thallus as well as the individual bionts. As a fi rst step, resource allocation and acquisition was investigated for a broad range of lichens aiming to determine the magnitude of metabolic variation across lichens. Seventy-fi ve lichen species were selected to cover as broad a spectrum as possible regarding taxonomy, morphology, habitat, and nitrogen requirements. The lichens had invested their nitrogen resources so that photosynthetic capacity matched respiratory carbon demand around a similar equilibrium across the contrasting species. Regulation of lichen growth was investigated in another study, using the two tripartite species <i>Nephroma arcticum</i> and <i>Peltigera aphthosa</i>, emphasizing the contribution of both internal and external factors. The empirical growth models for the two lichens were similar, showing that weight gain is to a higher extent dependent on those external factors that regulate their photosynthesis, whilst area gain is more controlled by internal factors, such as their nitrogen metabolism. This might be inferred from another study of the same species, where nitrogen manipulations resulted in an undisturbed weight gain, a similar resource allocation pattern between the bionts, but a distorted area gain. </p><p>Aiming to investigate lichen nitrogen relations even further, lichens’ capacities to assimilate combined nitrogen in the form of ammonium, nitrate and amino acids were assessed using 14 contrasting boreal species. All these had the capacity to assimilate all the three nitrogen forms, with ammonium absorption being more passive, and nitrate uptake being low in bipartite cyanobacterial lichens. Differences in uptake capacities between species were more correlated to photobiont than to morphology or substrate preferences. Finally, to investigate intra-specifi c plasticity in relation to altered nutrient supply, resource investments between photo- and mycobiont were investigated in the two bipartite green algal lichens <i>Hypogymnia physodes </i>and and <i>Platismatia glauca</i> in a low and a high nutrient environ- in a low and a high nutrient environ- ment. In both species, more of the resources had been directed to the photobiont in the high nutrient environment also increasing their overall carbon status. Taken together, my studies indicate that in spite of the apparent passive environmental control on lichen metabolism, these symbiotic organisms are able to both optimize and control their resource acquisition and allocation processes.</p>

<p>The pathogenic bacteria Yersinia pestis and Y. pseudotuberculosis are related to the degree where the former is considered a subspecies of the latter, and still they cause disease of little resemblance in humans. Y. pestis is the causative agent of lethal bubonic and pneumonic plague, while Y. pseudotuberculosis manifests itself as mild gastroenteritis. An important virulence determinant for these species is their ability to secrete and inject toxins (Yop effectors) into immune cells of the infected host, in a bacterium-cell contact dependent manner. This ability depends on the extensively studied type III secretion system, a highly complex multicomponent structure resembling a needle. The induction of Yop secretion is a strictly controlled event. The two structural type III secretion components YscU and YscP are here shown to play a crucial role in this process, which is suggested to require an YscP mediated conformational change of the C-terminus of YscU. Proteolytic cleavage of YscU within this domain is further revealed to be a prerequisite for functional Yop secretion. The needle subcomponent itself, YscF, is recognised as a regulatory element that controls the induction of Yop effectors and their polarised delivery into target cells. Potentially, the needle might act as a sensor that transmits the inducing signal (i.e. target cell contact) to activate the type III secretion system. Secondly a, for Yersinia, previously unexplored system, the Twin arginine translocation (Tat) pathway, is shown to be functional and absolutely required for virulence of Y. pseudotuberculosis. A range of putative Yersinia Tat substrates were predicted in silico, which together with the Tat system itself may be interesting targets for future development of antimicrobial treatments.</p>

Lichens are fascinating symbiotic systems, where a fungus and a unicellular alga, most often green (bipartite green algal lichens; 90% of all lichens), or a fi lamentous cyanobacterium (bipartite cyanobacterial lichens; 10% of all lichens) form a new entity (a thallus) appearing as a new and integrated organism: in about 500 lichens the fungus is associated with both a cyanobacterium and an alga (tripartite lichens). In the thallus, the lichen bionts function both as individual organisms, and as a symbiont partner. Hence, in lichens, the participating partners must both be able to receive and acquire resources from the other partner(s) in a controlled way. Lichens are particularly successful in harsh terrestrial environments. In part this is related to their poikilohydric nature and subsequent ability to repeatedly become desiccated and hydrated. Metabolic activity, i.e. photosynthesis, respiration, and for cyanobacterial lichens N2-fixation, is limited to periods when the thallus is suffi ciently hydrated. Mineral nutrients are mainly acquired from dry or wet deposition directly on the thallus. Taken together it then appears that lichens are to a large extent passively controlled by their environment, making their control over resource allocation and acquisition particularly challenging. The aim of this thesis was to investigate resource acquisition and allocation processes in different lichens, and to see how these respond to changes in resource availability. This was done by following lichen growth in the fi eld during manipulation of water, light, and nutrient supply, and by assessing the responses of both the integrated thallus as well as the individual bionts. As a fi rst step, resource allocation and acquisition was investigated for a broad range of lichens aiming to determine the magnitude of metabolic variation across lichens. Seventy-fi ve lichen species were selected to cover as broad a spectrum as possible regarding taxonomy, morphology, habitat, and nitrogen requirements. The lichens had invested their nitrogen resources so that photosynthetic capacity matched respiratory carbon demand around a similar equilibrium across the contrasting species. Regulation of lichen growth was investigated in another study, using the two tripartite species Nephroma arcticum and Peltigera aphthosa, emphasizing the contribution of both internal and external factors. The empirical growth models for the two lichens were similar, showing that weight gain is to a higher extent dependent on those external factors that regulate their photosynthesis, whilst area gain is more controlled by internal factors, such as their nitrogen metabolism. This might be inferred from another study of the same species, where nitrogen manipulations resulted in an undisturbed weight gain, a similar resource allocation pattern between the bionts, but a distorted area gain. Aiming to investigate lichen nitrogen relations even further, lichens’ capacities to assimilate combined nitrogen in the form of ammonium, nitrate and amino acids were assessed using 14 contrasting boreal species. All these had the capacity to assimilate all the three nitrogen forms, with ammonium absorption being more passive, and nitrate uptake being low in bipartite cyanobacterial lichens. Differences in uptake capacities between species were more correlated to photobiont than to morphology or substrate preferences. Finally, to investigate intra-specifi c plasticity in relation to altered nutrient supply, resource investments between photo- and mycobiont were investigated in the two bipartite green algal lichens Hypogymnia physodes and and Platismatia glauca in a low and a high nutrient environ- in a low and a high nutrient environ- ment. In both species, more of the resources had been directed to the photobiont in the high nutrient environment also increasing their overall carbon status. Taken together, my studies indicate that in spite of the apparent passive environmental control on lichen metabolism, these symbiotic organisms are able to both optimize and control their resource acquisition and allocation processes.

The pathogenic bacteria Yersinia pestis and Y. pseudotuberculosis are related to the degree where the former is considered a subspecies of the latter, and still they cause disease of little resemblance in humans. Y. pestis is the causative agent of lethal bubonic and pneumonic plague, while Y. pseudotuberculosis manifests itself as mild gastroenteritis. An important virulence determinant for these species is their ability to secrete and inject toxins (Yop effectors) into immune cells of the infected host, in a bacterium-cell contact dependent manner. This ability depends on the extensively studied type III secretion system, a highly complex multicomponent structure resembling a needle. The induction of Yop secretion is a strictly controlled event. The two structural type III secretion components YscU and YscP are here shown to play a crucial role in this process, which is suggested to require an YscP mediated conformational change of the C-terminus of YscU. Proteolytic cleavage of YscU within this domain is further revealed to be a prerequisite for functional Yop secretion. The needle subcomponent itself, YscF, is recognised as a regulatory element that controls the induction of Yop effectors and their polarised delivery into target cells. Potentially, the needle might act as a sensor that transmits the inducing signal (i.e. target cell contact) to activate the type III secretion system. Secondly a, for Yersinia, previously unexplored system, the Twin arginine translocation (Tat) pathway, is shown to be functional and absolutely required for virulence of Y. pseudotuberculosis. A range of putative Yersinia Tat substrates were predicted in silico, which together with the Tat system itself may be interesting targets for future development of antimicrobial treatments.

Diabetic nephropathy is the main cause for initiation of renal replacement therapy and early symptoms in patients include increased glomerular filtration rate (GFR), decreased oxygen tension and albuminuria, followed by a progressive decline in GFR and loss of kidney function. Experimental models of diabetes display increased GFR, decreased tissue oxygenation and nitric oxide bioavailability. These findings are likely to be intertwined in a mechanistic pathway to kidney damage and this thesis investigated their roles in the development of diabetic nephropathy. In vivo, diabetes-induced oxidative stress stimulates renal tubular Na+ transport and in vitro, proximal tubular cells from diabetic rats display increased transport-dependent oxygen consumption, demonstrating mechanisms contributing to decreased kidney oxygenation. In control animals, endogenous adenosine reduces vascular resistance of the efferent arteriole via adenosine A2-receptors resulting in reduced filtration fraction. However, in diabetes, adenosine A2-signalling is dysfunctional resulting in increased GFR via increased filtration fraction. This is caused by reduced adenosine A2a receptor-mediated vasodilation of efferent arterioles. The lack of adenosine-signaling in diabetes is likely due to reduced local adenosine concentration since adenosine A2a receptor activation reduced GFR only in diabetic animals by efferent arteriolar vasodilation. Furthermore, sub-optimal insulin treatment also alleviates increased filtration pressure in diabetes. However, this does not affect GFR due to a simultaneously induction of renal-blood flow dependent regulation of GFR by increasing the filtration coefficient. In diabetes, there is decreased bioavailability of nitric oxide, resulting in alterations that may contribute to diabetes-induced hyperfiltration and decreased oxygenation. Interestingly, increased plasma concentration of l-arginine, the substrate for nitric oxide production, prevents the development of increased GFR and proteinuria, but not increased oxygen consumption leading to sustained intra-renal hypoxia in diabetes. This thesis concludes that antioxidant treatment directed towards the NADPH oxidase as well maneuvers to promote nitric oxide production is beneficial in diabetic kidneys but is targeting different pathways i.e. transport-dependent oxygen consumption in the proximal tubule by NADPH oxidase inhibition and intra-renal hemodynamics after increased plasma l-arginine. Also, the involvement and importance of efferent arteriolar resistance in the development of diabetes-induced hyperfiltration via reduced adenosine A2a signaling is highlighted.

For the past 45 years, QKI has been studied for its role in the processes of development and central nervous system myelination using the qkv mouse. The presence of a single KH domain and the recent identification of a high-affinity binding site in mRNAs, suggests that it can bind to and regulate mRNAs through processes such as stability, splicing and transport. As a member of the STAR RNA binding family of proteins the QKI isoforms may also be involved in cell signaling pathways. / QKI's involvement in all of these processes, lead us to examine both the protein partners and the mRNA targets of the QKI complex in order to identify potentially new pathways regulated by QKI. In doing so, we identified a novel direct protein-protein interaction with PABP and for the first time described the relocalization of QKI to cytoplasmic granules following oxidative stress. In addition, in vivo mRNA interaction studies were performed and allowed the identification of approximately 100 new mRNA targets in human glioblastoma cells. One of the targets identified was VEGF mRNA. / Another QKI target mRNA is MBP, a major protein component of the myelin sheath and the candidate auto-antigen in multiple sclerosis (MS). In vivo MBP is symmetrically dimethylated on a single arginine residue. To further establish the role of the methylation of MBP in myelination, a methyl-specific antibody and an adenovirus expressing a recombinant protein arginine methyltransferase 5 (PRMT5) was generated. We show that methylated MBP is found in areas of mature myelin and that overexpression of the PRTM5 blocked the differentiation of oligodendrocytes. / Taken together these datas implicate QKI for the first time in the process of human cancer angiogenesis and could explain the vascularization defects observed in some of the qkI mutant mice. In addition, arginine methylation of MBP may prove to have an important role in the process of myelination and in the pathogenesis of demyelination and the autoimmune reaction in diseases such as MS.

Si l'intérêt nutritionnel des acides gras polyinsaturés (AGPI) n-3 dans la prise en charge et la prévention des dysfonctions associées au syndrome métabolique, est bien établi. Les mécanismes d'action spécifiques sous-jacents aux effets bénéfiques de cette famille d'acides gras sont encore en cours d'étude. L'objectif de ces travaux était d'explorer le rôle de l'acide alpha-linolénique ALA ou 18 :3 n-3, dans la modulation des voies affectant l'homéostasie de molécules bioactives dérivant du métabolisme secondaire des acides aminés (le monoxyde d'azote -NO- et le glutathion). L'hypothèse sous-jacente est que ces modulations pourraient expliquer, du moins en partie, le rôle des AGPI n-3 dans le maintien des fonctions biologiques contrôlées par ces métabolites (telles que la fonction endothéliale et le statut oxydant) et impliquées de près dans la physiopathologie du syndrome métabolique. Notre intérêt a porté particulièrement sur la voie de régulation génique via le PPARα et sur son implication dans le contrôle des gènes du métabolisme des acides aminés par l'ALA. Nous avons exploré chez la souris de type sauvage et invalidée pour le PPARα, l'effet de l'apport alimentaire d'ALA dans le cadre de régime normo- ou hyper-lipidiques sur les voies du métabolisme secondaire de l'arginine et de la cystéine. En parallèle nous nous sommes focalisés sur les effets de l'ALA au niveau vasculaire en utilisant un modèle de cellules endothéliales bovines en cultures. De ce travail de thèse s'est dégagé que l'ALA module effectivement le métabolisme secondaire de l'arginine et de la cystéine. L'apport d'ALA (à hauteur de 11% et 42% de l'apport énergétique) augmente la production de NO sans affecter l'expression hépatique des enzymes contrôlant l'utilisation de l'arginine (NOS et ARG). L'apport d'ALA (11%) augmente le pool hépatique du glutathion, alors que les plus forts apports d'ALA (42%) modulent l'expression des principales enzymes impliquées dans les voies d'utilisation de la cystéine (γGCL et CDO). Le PPARα ne semble pas être directement impliqué dans les effets observés de l'ALA, néanmoins, l'invalidation du PPARα rend le métabolisme secondaire des acides aminés plus sensible à la nature des acides gras alimentaire. Une meilleure biodisponibilité du NO et du glutathion suite à l'apport alimentaire d'ALA serait bénéfique pour la physiopathologie du syndrome métabolique. Il semble donc intéressant, à l'issus de ce travail, d'élaborer des études nutritionnelles validant ces effets de l'ALA chez l'homme dans une perspective de recommandations nutritionnelles.

Les "protéine arginine méthyltransférases" (PRMT) sont impliquées dans de nombreux processus cellulaires : transcription, maturation et transport des ARN, traduction, transduction du signal, réplication et réparation de l'ADN, et apoptose. Différents travaux ont montré que des dérégulations de ces mécanismes impliquant les PRMT peuvent induire certains cancers, faisant de ces enzymes de nouvelles cibles potentielles en chimiothérapie. Il s'avère donc crucial de comprendre le mode d'action des PRMT à l'échelle atomique, à la fois au niveau fondamental et pour le développement de nouveaux médicaments. Les travaux décrits ici s'intéressent à la protéine PRMT4/CARM1 et s'appuient sur des études structurales par bio-cristallographie, pour comprendre les mécanismes de la réaction de méthylation catalysée par CARM1 et découvrir des inhibiteurs spécifiques, mais aussi sur des études en solution, pour caractériser l'interaction entre CARM1 et ses substrats.

Tez (Tıpta Uzmanlık) - Süleyman Demirel Üniversitesi, Tıp Fakültesi, Çocuk Cerrahisi Anabilim Dalı, 2006. / Kaynakça var.