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N-linked glycosylation in Campylobacter jejuni and Campylobacter fetus and N-linked glycans as targets for antibody-based detectionWeaver, Danielle January 2017 (has links)
Campylobacter spp., especially C. jejuni and C. coli, are the leading cause of bacterial gastroenteritis in Europe. There is a recognised need to develop detection tools which can be performed on farms to facilitate reducing the presence of Campylobacter in poultry. A similar application could be beneficial for detection of C. fetus, a veterinary pathogen which causes significant economic loss in the cattle industry. Campylobacter species perform protein N-linked glycosylation and in C. jejuni at least 150 proteins, many of which are surface-exposed, may be modified. Therefore, the first portion of this thesis investigated the feasibility of using N-linked glycans as targets for antibody-based detection of Campylobacter species. To do this, a His-tagged N-glycoprotein was expressed and purified from C. fetus and used as immunogen to raise an antiserum termed CfNgp. The Campylobacter N-glycan reactivity of this antiserum was characterised and it was shown to react with N-glycoproteins and cells of C. fetus and other emerging Campylobacter species such as C. concisus. Immunoblotting techniques and flow cytometry were used to characterise an antiserum (CjNgp) raised against a C. jejuni N-linked glycoprotein and demonstrated that it can specifically detect cells of C. jejuni, C. coli and other emerging Campylobacter species found in poulty. This thesis also describes the investigation of the relatively uncharacterised C. fetus N-linked glycosylation system. Functional analysis of C. fetus predicted glycosyltransferases was acheived by developing glycocompetent E. coli containing a hybrid C. jejuni/C. fetus pgl system. The N-glycan structures biosynthesised were analysed using mass spectrometry and this novel approach discovered the activity of two C. fetus glycosyltransferase enzymes. Finally, this work used a bioinformatics pipeline to produce a C. fetus predicted N-linked glycoproteome and experimentally verified a newly identified N-linked glycoprotein. This pipeline was also applied to investigate the putative conservation of N-linked glycoproteins throughout the Campylobacter genus and highlighted âcoreâ N-linked glycoproteins which are key targets for experimental investigation. Overall, this work demonstrates that Campylobacter N-linked glycans are attractive targets for antibody-based detection, expands our knowledge of C. fetus N-linked glycosylation and contributes to the broader understanding of this intriguing aspect of Campylobacter biology.
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Thiofonctions insolites sur charpentes saccharidiques / Uncommon thiofunctions on saccharidic frameworksSchleiss, Julie 09 December 2009 (has links)
Les glucosinolates (GLs) sont des métabolites secondaires très présents dans la famille des Brassicaceae, une famille de végétaux connus dans l’alimentation humaine pour leurs propriétés gustatives et aussi pour leurs effets chimio-préventifs. La myrosinase (E.C. 3.2.1.147) est la seule enzyme capable d’hydrolyser les GLs. Nous nous sommes intéressés aux produits obtenus lors de cette dégradation - les isothiocyanates (ITCs) mais aussi à la fonction thiohydroximate, et plus particulièrement à la synthèse de nitrones thiofonctionnalisées. La synthèse d’analogues d’ITC ainsi que de certains de leurs thio-conjugués a conduit à une large gamme de molécules permettant de cerner les implications chimio-préventives et les potentiels en bio-activité (notamment contre Plasmodium falciparum). Partant d’observations analytiques relatives à certains GLs comme la glucoraphénine, il a été découvert qu’un thiohydroximate pouvait présenter un caractère nucléophile comparable à celui d’une oxime dans un processus cyclisant du type Grigg. Nous avons dès lors cherché à développer de nouvelles voies d’accès à un système fonctionnel très peu décrit dans la littérature : les N-oxydes de thioimidate (OTI). Une étude de réactivité d’un OTI-modèle a révélé des comportements originaux, en particulier dans des réactions de couplage pallado-catalysées qui ouvrent un accès à des nitrones cycliques originales et peu aisées à préparer par des voies plus classiques. / Glucosinolates (GLs) are widespread secondary metabolites in Brassicaceae, a family of vegetables known in human feeding for their tastes and also for their chemo-prevention effects. Myrosinase (E.C. 3.2.1.147) is the only enzyme able to hydrolyze GLs. We have been interested in products acquired during this degradation - isothiocyanates (ITCs) but also in the thiohydroximate function, and more particularly in the synthesis of thiofunctionalized nitrones. The synthesis of ITC analogues as well as some of their thio-conjugates has led to a broad range of molecules allowing to surround chemo-preventive involvements and potentials in bio-activity (namely against Plasmodium falciparum). Starting from analytical observations related to some GLs such as glucoraphenin, it has been disclosed that a thiohydroximate could display a nucleophilic character comparable to that of an oxime in a Grigg-type cyclic process. We have developed new pathways to a scarcely described functional system : thioimidate N-oxides (OTI). Reactivity studies on a model-OTI have revealed an atypical behaviour, notably in palladium-catalyzed coupling reactions : those open the way to original cyclic nitrones which are not easily available via standard methods.
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Expression of the heparan sulfate biosynthesis enzymes NDST1 and NDST2 and their major splice variants in human tissues.Kristoffersson, Fredrik January 2018 (has links)
The aim of the study was to investigate the expression NDST transcripts in a wide variety of tissues using RNA-sequencing experimental data from five published studies, using two common in silico tools: the Tophat-Cufflink pipeline and the HTSeq-DEXSeq pipeline. We show that to detect NDST alternative transcripts, paired-end sequencing should be used with replicates of samples or conditions together with 100 base read length to allow for reliable detection of the low expressed transcripts in the NDST family. As a demonstration project, we also characterized HS synthesized by the adrenal carcinoma (ACC) cell line H295R and determined expression of NDSTs in the cells and in ACC tumor samples. We could show that roughly 65% of newly synthesized proteoglycans isolated after metabolic 35S-sulfate labeling of the cells are made up of heparan sulfate (HS) with an average chain length of 45 kDa. The HS chains show a high frequency of N-sulfation and a high total degree of sulfation. Interestingly, disaccharide analysis demonstrated a three-time higher amount of stored chondroitin sulfate (CS) compared to HS in the ACC cell line.
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Development and understanding of III-N layers for the improvement of high power transistors / Développement et compréhension des couches III-N pour l'amélioration des transistors de haute puissanceBouveyron, Romain 31 October 2017 (has links)
Cette thèse est principalement axée sur le développement des matériaux III-N pour les transistors de puissance HEMTs, ainsi que les multipuits quantiques et les applications optroniques qui en découlent dans une moindre mesure. Suite à un rappel des propriétés des nitrures, des différentes applications possibles, du principe de la MOCVD et des différentes caractérisations retenues pour ce travail, nous avons traité dans un premier temps la croissance de GaN à basse température, c'est-à-dire en dessous de 1050degres C. La fabrication de multipuits impliquant l’alternance des couches de GaN et d'InAlN ou InGaAlN nous contraint de travailler à ces températures ce qui génère l’apparition d’un défaut en surface du GaN que l’on nomme V-defect. Une étude expérimentale poussée nous a permis de comprendre comment apparaissent et évoluent ces défauts selon les paramètres de croissance. Un modèle basé sur les énergies de surface à pu être élaboré et explique l’évolution de ces défauts. Ensuite nous avons défini l'influence de nombreux paramètre de croissance par MOCVD et tiré, des multiples tendances mises en relief, des modèles et explications justifiant telle ou telle propriété physique et chimique du matériau. En aval, ce sont des caractérisations électriques et principalement des mesures de résistivités qui ont été traitées afin de comparer la performance de nos échantillons à base d'indium à ceux de type AlGaN/GaN. Le problème de la pollution au gallium dans les réacteurs MOCVD verticaux a été mis en évidence et nous avons proposé différentes solutions pour la limiter, voire l’annihiler. Pour terminer ce sont des couches de protection à base de SiN et GaN que nous avons tenté de développer afin de protéger nos alliages à base d’indium pour la suite des étapes technologiques nécessaires à la fabrication d’un composant par exemple. / This thesis is mainly focused on the development of III-N materials for HEMTs power transistors, as well as quantum wells and optronics applications that result to a lesser extent. Following a reminder of the properties of nitrides, the different possible applications, the principle of the MOCVD and the different characterizations used for this work, we first treated the growth of GaN at low temperature, that is to say below 1050degres C. The manufacture of multiple quantum wells involving the alternation of GaN and InAlN or InGaAlN layers forces us to work at these temperatures, which generates the appearance of a defect in surface of the GaN which is called V-defect. An advanced experimental study allowed us to understand how these defects appear and evolve according to the growth parameters. A model based on surface energies could be developed and explains the evolution of these defects. Then we defined the influence of many MOCVD growth parameters by MOCVD and derived, from the multiple trends highlighted, the models and explanations justifying this or that physical and chemical property of the material. Downstream, these are electrical characterizations and mainly resistivity measurements that have been processed to compare the performance of our indium-based samples to those of AlGaN/GaN type. The problem of gallium pollution in vertical MOCVD reactors has been highlighted and we have proposed different solutions to limit or even annihilate it. Finally, we have tried to develop protective layers based on SiN and GaN in order to protect our indium-based alloys for the next technological steps required to manufacture a component, for example.
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Formas de nitrogênio orgânico em solos tratados com esterco bovino / Forms of organic nitrogen in soils treated with cattle manureAdame, Cássia Rita [UNESP] 23 April 2018 (has links)
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Previous issue date: 2018-04-23 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O conhecimento das alterações na distribuição do N entre os reservatórios existentes no solo após aplicação de esterco bovino permite melhorar a compreensão dos efeitos da aplicação do adubo orgânico na disponibilidade de N para as plantas. Os objetivos com o presente foram avaliar as transformações do nitrogênio do esterco bovino em função da textura do solo e do tempo, e associar as formas de N orgânico com o N potencialmente disponível. O experimento foi conduzido em esquema fatorial, delineamento inteiramente ao acaso e quatro repetições. Os tratamentos foram resultantes da combinação de dois solos (argiloso, com 440 g kg-1 de argila, e arenoso, com 120 g kg-1 de argila), duas doses de esterco bovino (0 e o equivalente a 20 t ha-1) e quatro tempos de incubação (15, 45, 90 e 180 dias). Nas amostras de solo foram determinados pHCaCl2, C orgânico, N total, N extraído por destilação a vapor direta, N-NH4+, N-NO3-, e as seguintes frações do N orgânico: N-NH4+ hidrolisável, N-aminoaçúcares, N-aminoácidos, N-total hidrolisável e N-insolúvel em ácido. Por cálculo foi obtido o N-não identificado. A aplicação de esterco aumenta as frações de N orgânico de mais fácil mineralização até próximo de 100 dias após a aplicação, e posteriormente, aumenta as frações de N orgânico de maior estabilidade, principalmente no solo argiloso. O N potencialmente disponível determinado por destilação a vapor direta correlacionou com as frações de N mais disponíveis, N-NH4+ hidrolisável, N-aminoaçúcares e N-aminoácidos. / The knowledge of the changes in the N distribution among the soil existing N pools after cattle manure additions, allows to improve the understanding of the effects of organic fertilizer additions on N availability to plants. The aim of this study was to evaluate the nitrogen transformations of cattle manure as a function of soil texture and of time, and to associate organic N forms with the potentially available N. The experiment was carried out in a factorial scheme, completely randomized design with four replicates. The treatments were the result of a combination of two soils (typic Hapludox clayey, with 440 g kg-1 clay, and arenic Hapludult, sand, with 120 g kg-1 clay), two doses of cattle manure (0 and 20 t ha-1) and four incubation times (15, 45, 90 and 180 days). In the soil samples were determined, pHCaCl2, organic C, total N, N extracted by direct steam distillation, NH4 + -N, NO3 - -N and the following organic N fractions: ammonia-N, amino sugar-N, amino acid-N, total hydrolysable-N and non-hydrolyzable-N. By calculation it was obtained the hydrolyzable unknown-N. The cattle manure additions increases the organic N fractions of easier mineralization until about 100 days after the addition, and later, it increases the fractions of organic N of greater stability, mainly in the clay soil. Potentially available N determined by direct steam distillation correlated with the most available N fractions, NH4 + -N hydrolysable, amino sugars-N and amino acids-N.
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Multi-scale approach of the formation and evolution of star clusters / Approche multi-échelle de la formation et l'évolution des amas d'étoilesDorval, Julien 30 September 2016 (has links)
Les jeunes amas d'étoiles sont sous-structurés et évoluent dynamiquement pour former des amas sphériques à l'équilibre. Je présente une nouvelle méthode pour générer des conditions initiales réalistes pour simuler ce processus: la fragmentation de Hubble-Lemaitre. Je laisse le système développer spontanément des surdensités au cours d'une expansion du système. Le modèle résultant se compare bien aux simulations hydrodynamiques de formation stellaire et aux observations des jeunes amas. Le modèle fragmenté s'effondre de manière plus douce qu'un modèle uniforme. L'injection d'une population d'étoile binaire avant l'effondrement a montré qu'un système sous-structuré détruisait bien plus de binaires qu'un système à l'équilibre. Des binaires particulièrement larges ou serrées, jusqu’à 0.01 AU, ont également été détectées dans ces modèles. Cette méthode est très prometteuse, un exemple d'application est la génération d'observations synthétiques de régions de formation stellaire. / Young star clusters are substructured and undergo a dynamical evolution erasing this substructure to form relaxed spherical clusters. I present a new method to generate realistic initial conditions to perform N-body simulations of this process: the Hubble-Lemaitre fragmentation. By expanding an initially uniform sphere, I allow spontaneous overdensities to grow, creating a realistic model for young clumpy stellar systems. This method is validated by analysing the distribution and content of the clumps and comparing them to hydrodynamical simulations of star formation as well as observations of star forming regions. These systems undergo a softer collapse than uniform ones. I injected binary stars in the fragmented models and found they were heavily processed when substructure was present. I also found extreme short and tight binaries, down to 0.01 AU, to formin the models. The method has a lot of potential, such as the generation of mock observations of star-forming regions.
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Camargo Guarnieri: uma análise das sonatinas n.3 e n.6 para pianoRibas, Geraldo Majela Brandão January 2002 (has links)
O presente trabalho pretende analisar as fugas das Sonatinas nº3 e nº6 para piano de Camargo Guarnieri, através de uma análise estilística e tendo em vista os procedimentos utilizados pelo compositor especificamente no tratamento da fuga como técnica composicional. Guarnieri compôs 8 sonatinas para piano escritas entre 1928 e 1982, período que abrange grande parte da vida criativa do compositor. A análise das duas as fugas enfocará cinco parâmetros, conforme o esquema analítico de Jan LaRue: Som, Harmonia, Melodia, Ritmo e Crescimento. Através desses parâmetros, verificaremos como se desenvolvem estruturalmente as fugas, destacando os aspectos mais importantes que caracterizarão o discurso musical desenvolvido pelo compositor.
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Avaliação do desempenho de catalisadores do tipo Pt-Re-Sn/Al2O3 na reforma de n-octano.Carvalho, Luciene Santos de January 2003 (has links)
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Previous issue date: 2003 / Catalisadores Pt-Re-Sn/Al2O3-Cl foram avaliados na reforma de n-octano para produção de compostos aromáticos, especialmente xilenos, e foram comparados com o catalisador monometálico (Pt/Al2O3) e catalisadores bimetálicos (Pt-Re e Pt-Sn/Al2O3) correspondentes. As amostras foram preparadas por coimpregnação e impregnações sucessivas da alumina, com as soluções dos precursores metálicos. Os sólidos foram, então, secos (120oC), calcinados (500oC, 4h, ar) e reduzidos (500oC, 4h, H2). No caso das impregnações sucessivas, os sólidos foram calcinados e reduzidos após cada adição de metal. Os catalisadores contendo rênio foram previamente sulfetados com dissulfeto de carbono. As seguintes amostras foram preparadas (0,3% p/p de cada metal): Pt/Al2O3, Re/Al2O3 e Sn/Al2O3; (Pt+Re)/Al2O3, (Pt+Sn)/Al2O3, (Re+Sn)/Al2O3 e (Pt+Re+Sn)/Al2O3, preparados por coimpregnação; Pt-Re/Al2O3, Pt-Sn/Al2O3, Pt-Re-Sn/Al2O3, Pt-Sn-Re/Al2O3, Re-Pt-Sn/Al2O3, Re-Sn-Pt/Al2O3, Sn-Pt-Re/Al2O3, Sn-Re-Pt/Al2O3, preparados por impregnações sucessivas. As funções ácida e metálica dos catalisadores foram avaliadas através das reações modelo de isomerização de n-pentano e desidrogenação de ciclohexano, respectivamente. A tiotolerância dos catalisadores foi avaliada na desidrogenação de ciclo-hexano. As amostras também foram caracterizadas por análise elementar, redução à temperatura programada (TPR), espectroscopia de infravermelho com transformadas de Fourier (FTIR) de CO adsorvido, quimissorção de H2, microscopia eletrônica de transmissão (TEM) e difração de elétrons (ED). Após os testes de isomerização de n-pentano e reforma de n-octano, as amostras foram analisadas por oxidação à temperatura programada (TPO). Observou-se que a atividade de desidrogenação da platina foi reduzida por rênio e/ou estanho, e este efeito foi mais forte com o estanho. As energias de ativação na desidrogenação de ciclo-hexano foram mais afetadas pelo estanho, que modificou os sítios ativos, produzindo outros de atividade mais baixa. Ambos os metais podem formar ligas com a platina, como mostrado pelos experimentos de TPR e ED. Estes metais tornam a platina mais rica em elétrons, diminuindo sua capacidade de quimissorção. A existência deste efeito eletrônico foi confirmada por FTIR de CO adsorvido. O enriquecimento eletrônico da platina também afetou a tiotolerância, uma vez que a ligação Pt-S tornou-se mais forte. Por isso, os catalisadores bimetálicos apresentaram uma tiotolerância mais baixa do que o catalisador monometálico, e os trimetálicos foram ainda mais susceptíveis ao envenenamento por enxofre, devido à ação conjunta dos dois metais sobre a platina. Nas amostras preparadas por coimpregnação, o envenenamento foi mais severo, por causa do melhor contato entre os metais. A função ácida também foi afetada pela presença de estanho e rênio, principalmente na forma de óxidos. Nos catalisadores trimetálicos, efeitos positivos foram encontrados quando o estanho foi adicionado primeiro, porque o óxido de estanho reduziu a quantidade de sítios ácidos mais fortes da alumina, produzindo uma acidez mais conveniente às reações de isomerização e ciclização. Dessa forma, o catalisador Sn-Pt-Re-S/Al2O3 foi o mais promissor em reforma de n-octano, com a mais alta seletividade a xilenos, maior estabilidade e produção de gases mais baixa. O catalisador trimetálico coimpregnado mostrou um desempenho similar e tem a vantagem adicional de não precisar ser previamente sulfetado. / Salvador
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Camargo Guarnieri: uma análise das sonatinas n.3 e n.6 para pianoRibas, Geraldo Majela Brandão January 2002 (has links)
O presente trabalho pretende analisar as fugas das Sonatinas nº3 e nº6 para piano de Camargo Guarnieri, através de uma análise estilística e tendo em vista os procedimentos utilizados pelo compositor especificamente no tratamento da fuga como técnica composicional. Guarnieri compôs 8 sonatinas para piano escritas entre 1928 e 1982, período que abrange grande parte da vida criativa do compositor. A análise das duas as fugas enfocará cinco parâmetros, conforme o esquema analítico de Jan LaRue: Som, Harmonia, Melodia, Ritmo e Crescimento. Através desses parâmetros, verificaremos como se desenvolvem estruturalmente as fugas, destacando os aspectos mais importantes que caracterizarão o discurso musical desenvolvido pelo compositor.
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Efeitos da ayahuasca na memoria emocional de ratos / Effects of ayahuasca on emotional memory in ratsSilva, Daiana Aparecida da [UNIFESP] January 2012 (has links) (PDF)
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Previous issue date: 2012 / A ayahuasca e uma palavra da lingua nativa americana Quechua comumente traduzida como cipo das almas. E uma decoccao alucinogena preparada com plantas psicoativas. O cha contem N, N-dimetiltriptamina (DMT), um potente agente psicodelico proveniente da Psychotria viridis e tambem contem os alcaloides β-carbolinicos contidos na Banisteriopsis caapi. Estas carbolinas β- carbolinas inibem a enzima monoaminaoxidase e, desta maneira as β-carbolinas protegem DMT de ser degradada. Assim, DMT e capaz de atravessar a barreira hematoencefalica, se liga a receptores 5-HT2, exercendo o seu efeito. Estudos mostram que os voluntarios relataram um estado altamente emocional e, correspondentemente, a inGestão da ayahuasca causou uma elevada atividade cerebral na amigdala e giro parahipocampal, estruturas envolvidas na aprendizagem emocional e memoria. Utilizando os modelos de condicionamento de medo ao contexto e ao som, nos verificamos se a administracao oral de ayahuasca antes, imediatamente apos a o treino, e a manipulacao farmacologica pre-teste poderia interferir com os processos mnemonicos. Os nossos resultados mostraram que as administracoes das doses 250, 500 ou 750 mg/kg nao afetaram a aquisicao das tarefas de CMC e CMS. Diferentes doses de ayahuasca (50 ou 500 mg/kg) administradas imediatamente apos o treino nao afetaram a consolidacao do CMC. Alem disso, as doses 50 e 500 mg/kg nao alteraram a consolidacao do CMS. A administracao pre-teste de ayahuasca (50 e 500 mg/kg) nao alterou o teste de evocacao 1 em ambas as tarefas (CMC/CMS), e nem o teste de evocacao 2 para o CMS. No entanto, a administracao pre-teste de ayahuasca 500 mg/kg causou um decrescimo significativo no comportamento de congelamento dos ratos do teste de evocacao 1 para o teste 2, na tarefa de condicionamento de medo ao contexto. Estes resultados sugerem que a ayahuasca pode facilitar a extincao da memoria aversiva dependente principalmente do hipocampo e possivelmente da amigdala / BV UNIFESP: Teses e dissertações
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