A Organização Mundial da Saúde recomenda o teste de Imunofluorescência Direta (IFD) para a realização do Diagnóstico Laboratorial e Avaliação Sorológica da raiva. Como reveladores deste teste, são utilizados conjugados fluorescentes antirribonucleoproteínas (RNPs) do vírus da raiva, produzidos a partir de anticorpos anti-RNPs obtidos da purificação de soros hiperimunes de animais imunizados com RNPs purificadas. Os objetivos deste estudo foram: avaliar os efeitos da radiação gama na imunogenicidade das RNPs e comparar dois métodos cromatográficos de purificação de imunoglobulinas anti-RNPs. Os soros de animais imunizados com RNPs irradiadas e não irradiadas foram avaliados nos testes de Imunfluorescência Indireta e Ensaio Imunoenzimático. A partir dos resultados obtidos pode-se concluir que os animais imunizados com RNPs irradiadas necessitam de um menor número de doses para uma resposta imunológica com alto título de anticorpos. Por meio da IFD verificou-se que o conjugado produzido com anticorpos anti-RNPs irradiadas apresentou especificidade semelhante a do conjugado produzido a partir de anticorpos anti-RNPs não irradiadas, mas com melhor definição das inclusões características do vírus. Os processos de purificação de anticorpos por cromatografia de troca iônica e cromatografia de afinidade foram avaliados utilizando-se os testes de Bradford e eletroforese (SDS-PAGE). Pelos resultados obtidos pode-se concluir que, neste estudo, o processo de purificação que utilizou a cromatografia de afinidade foi o método que apresentou melhor rendimento, menor tempo de execução e obtenção de anticorpos com maior grau de pureza. / The World Health Organization recommends the direct immunofluorescence test for laboratory diagnosis and serological evaluation of rabies. To achieve this test, fluorescent anti-ribonucleoproteins (RNPs) conjugates, produced from purified IgGs of RNP-immunized animals are employed. The aims of the present study were: investigate the effects of gamma radiation on the immunogenicity of RNPs, as well as to compare two chromatographic methodologies for the purification of anti-RNPs immunoglobulins. Sera from animals immunized with either native or irradiated RNPs were compared by direct immunofluorescence and immunoenzymatic assays. Our results indicate that the animals immunized with irradiated antigen requested a lower number of doses to reach high antibody titers. The immunofluorescence assays indicated that the conjugates produced with the anti-irradiated RNPs IgGs showed similar specificity to its anti-native counterpart, but with a higher definition of the virus inclusions. The purification methods were compared by Bradford and electrophoresis assays. According to the results, we concluded that the affinity-based process resulted in higher yields, lower execution time, and higher purity of the antibodies.

A purificação de subunidades do vírus da raiva pode ser realizada por diferentes metodologias, uma vez purificadas estas subunidades podem ter diversas aplicações em métodos altamente específicos para o diagnóstico laboratorial e pesquisa da raiva. A obtenção de ribonucleoproteínas (RNP) do vírus da raiva pode ser realizada por meio de ultracentrifugação em gradiente de Cloreto de Césio (CsCl), porém este método possibilita a obtenção de RNP semi purificadas. Neste estudo foi utilizado o método de cromatografia de imunoafinidade para obtenção das RNP, os resultados obtidos foram satisfatórios quanto a um maior grau de pureza dessas proteínas, além de propiciar a otimização do processo e redução do tempo operacional, quando comparado a ultracentrifugação em gradiente de CsCl. / Purification of subunits of the rabies virus can be accomplished by different methodologies, once purified these subunits can have several applications in highly specific methods for diagnostic and research laboratory for rabies. Obtaining ribonucleoprotein (RNP) of rabies virus can be performed by ultracentrifugation in a Cesium Chloride (CsCl) gradient, but this method allows to obtain semi purified RNP. This study used the method of immunoaffnity chromatography to obtain the RNP; the results were satisfactory for a higher degree of purity of these proteins in addition to providing process optimization and reduced operating time compared to ultracentrifugation in a cesium chloride gradient.

A Organização Mundial da Saúde recomenda o teste de Imunofluorescência Direta (IFD) para a realização do Diagnóstico Laboratorial e Avaliação Sorológica da raiva. Como reveladores deste teste, são utilizados conjugados fluorescentes antirribonucleoproteínas (RNPs) do vírus da raiva, produzidos a partir de anticorpos anti-RNPs obtidos da purificação de soros hiperimunes de animais imunizados com RNPs purificadas. Os objetivos deste estudo foram: avaliar os efeitos da radiação gama na imunogenicidade das RNPs e comparar dois métodos cromatográficos de purificação de imunoglobulinas anti-RNPs. Os soros de animais imunizados com RNPs irradiadas e não irradiadas foram avaliados nos testes de Imunfluorescência Indireta e Ensaio Imunoenzimático. A partir dos resultados obtidos pode-se concluir que os animais imunizados com RNPs irradiadas necessitam de um menor número de doses para uma resposta imunológica com alto título de anticorpos. Por meio da IFD verificou-se que o conjugado produzido com anticorpos anti-RNPs irradiadas apresentou especificidade semelhante a do conjugado produzido a partir de anticorpos anti-RNPs não irradiadas, mas com melhor definição das inclusões características do vírus. Os processos de purificação de anticorpos por cromatografia de troca iônica e cromatografia de afinidade foram avaliados utilizando-se os testes de Bradford e eletroforese (SDS-PAGE). Pelos resultados obtidos pode-se concluir que, neste estudo, o processo de purificação que utilizou a cromatografia de afinidade foi o método que apresentou melhor rendimento, menor tempo de execução e obtenção de anticorpos com maior grau de pureza. / The World Health Organization recommends the direct immunofluorescence test for laboratory diagnosis and serological evaluation of rabies. To achieve this test, fluorescent anti-ribonucleoproteins (RNPs) conjugates, produced from purified IgGs of RNP-immunized animals are employed. The aims of the present study were: investigate the effects of gamma radiation on the immunogenicity of RNPs, as well as to compare two chromatographic methodologies for the purification of anti-RNPs immunoglobulins. Sera from animals immunized with either native or irradiated RNPs were compared by direct immunofluorescence and immunoenzymatic assays. Our results indicate that the animals immunized with irradiated antigen requested a lower number of doses to reach high antibody titers. The immunofluorescence assays indicated that the conjugates produced with the anti-irradiated RNPs IgGs showed similar specificity to its anti-native counterpart, but with a higher definition of the virus inclusions. The purification methods were compared by Bradford and electrophoresis assays. According to the results, we concluded that the affinity-based process resulted in higher yields, lower execution time, and higher purity of the antibodies.

Les virus ne sont rien de plus que des particules composées de lipides et/ou de protéines qui encapsulent de l'information génétique composée d'ARN ou d'ADN. Au cours du cycle viral, les virus entrent dans la cellule hôte où ils dupliquent leur génome, puis forment de nouvelles particules virales qui ressortiront de la cellule pour se diffuser. Alors que pour produire leurs protéines virales les virus détournent la machinerie cellulaire, ils utilisent pour la plupart leur propre polymérase spécifique pour répliquer leur génome.Les Bunyaviridae sont une grande famille des virus à ARN simple brin segmenté de polarité négative. Les Arenaviridae et les Orthomyxoviridae sont les deux autres familles de ce type. Certains bunyavirus provoquent des maladies humaines graves, comme des fièvres hémorragiques, des encéphalites et des méningites. D'autres infectent des plantes et animaux, posant une menace économique sérieuse en agronomie.Les ARN polymérases ARN-dépendante de virus à ARN négatif segmenté sont des machineries multi-fonctionnelles, capables de répliquer le génome viral et de le transcrire en ARNs messagers. La réplication est effectuée de novo, en utilisant un intermédiaire d'ARN complémentaire de polarité positive, alors que la transcription est initiée par vol de coiffe d'ARN cellulaire. Chaque segment du génome viral est recouvert par des nucléoprotéines et fixé à la polymérase par ses extrémités 3' et 5' conservées. Le complexe ARN viral/nucléoprotéines/polymérase forme une ribonucléoprotéine, qui est l'unité fonctionnelle de la réplication/transcription.L'objectif de mon projet de thèse était la caractérisation structurale et fonctionnelle de la polymérase du virus La Crosse, également nommée protéine L. Ce projet était basé sur l'hypothèse que toutes les polymérases de virus à ARN négatif segmenté pourraient partager une organisation et un mode d'action similaire. Lors de la première année de ma thèse, j'ai tenté de caractériser le domaine C-terminal, que nous supposions être responsable de la fixation de coiffe. Au cours de la deuxième année, j'ai étendu mes recherches sur l'étude de l'interaction entre les extrémités de l'ARN viral et la protéine L (protéine entière et construction tronquée en C-terminal). Confronté à des difficultés pour établir des tests de réplication et de transcription in vitro, j'ai poursuivi mes recherches en troisième année avec l'étude d'interactions et de co-cristallisation entre polymérase et ARN viral. Cela a finalement conduit au résultat principal de ma thèse - la détermination de la structure par cristallographie aux rayons X de la polymérase de virus de La Crosse en complexe avec les extrémités 3' et 5' de l‘ARN viral. La structure obtenue constitue une percée dans le domaine de bunyavirus. Elle révèle – à la différence de ce qui avait été initialement proposé – que les extrémités 3' et 5' de l'ARN se lient dans deux sites séparés et conservés. La liaison de l'extrémité 5' de l'ARN viral stabilise de façon allostérique l'un des motifs catalytiques du site actif de la polymérase. La structure révèle l'existence de deux tunnels séparés pour l'ARN produit et l'ARN matrice de sortir, ce qui suggère que le brin d'ARN naissant est séparé de la matrice et quitte la polymérase comme ARN simple brin. La proximité des tunnels d'entrée et de sortie de la matrice explique comment la polymérase peut se déplacer le long de l'ARN génomique avec une perturbation minimale de la ribonucléoprotéine.En parallèle de la structure de la polymérase du virus La Crosse, les structures des polymérases hétérotrimériques de la grippe A et B en complexe avec l'ARN viral ont également été déterminées au sein du groupe du Dr. Stephen Cusack. La comparaison de l'organisation des polymérases des deux familles et de la nature de leur liaison avec l'ARN viral montre que, malgré une homologie de séquence minimale, des similitudes structurelles sont frappantes. Cela suggère fortement la présence d'un ancêtre commun. / Viruses are not more than particles composed of lipids and/or proteins with genetic information – the viral RNA or DNA genome – embedded inside. In order to be efficient, once they enter the host cell they need to multiply this genetic information, package it into new viral particles and spread out from the cell. While in order to produce viral proteins viruses highjack cellular machinery, for replicating their genome most viruses use their own, specialized polymerases.Bunyaviridae is the largest viral family of segmented negative-strand RNA viruses, comprising also Arenaviridae and Orthomyxoviridae families. Some bunyaviruses are causative agents of severe human diseases including heamorrhagic fevers, encephalitis and meningitis. Others infect a variety of plants and animals posing a significant economic threat to the crop cultivation and cattle breeding.RNA-dependent RNA polymerases of segmented negative-strand RNA viruses are multifunctional machines, able to perform both de novo genome replication via positive-strand cRNA intermediate, and viral mRNA transcription using cap-snatched host-derived mRNA primer. Viral RNA genome of bunyaviruses, arenaviruses, and orthomyxoviruses is divided into three, two, and eight segments respectively. Each segment, coated by nucleoproteins and attached through its conserved 3′ and 5′ ends to the polymerase, constitutes an individual ribonucleoprotein particle – an autonomous RNA synthesis unit.The scope of the PhD project described in this thesis was the structural and functional characterization of the La Crosse orthobunyavirus polymerase, also named the L protein. It was based on the hypothesis that all polymerases of segmented negative-strand RNA viruses share a similar domain organization and mode of action. During the 1st year attempts were made to confirm and characterize a putative C-terminal cap-binding domain. During the 2nd year project was extended to study 3′ and 5′ vRNA ends interactions with the full length and C-terminus truncated L protein. Facing difficulties to establish replication and transcription assays in vitro, vRNA binding studies and co-crystallizastion were continued during the 3rd year. This finally led to the main achievement of the thesis – the x-ray structure of La Crosse orthobunyavirus polymerase in complex with vRNA. Obtained structure is a breakthrough in the bunyavirus field. It reveals – unlike it was initially believed – conserved, sequence specific and separate binding sites for 3′ and 5′ vRNA ends located within the polymerase. The 5′ vRNA end binding allosterically structures one of the conserved catalytic motifs within the polymerase active site. The structure sheds also some new light on bunyaviral replication and transcription mechanisms. There exist two distinct product and template exit channels, suggesting that the nascent RNA strand is separated from the template and leaves the polymerase as the single-strand RNA. Close proximity of the template entry and exit channels explains how the polymerase can translocate along the genomic template with minimal disruption of the RNP.In parallel to the La Crosse polymerase structure, structures of Influenza A and B heterotrimeric polymerases in complex with vRNA were also obtained in Stephen Cusack group. This gave a great opportunity to compare the domain organization and the nature of vRNA binding by viral polymerases belonging to Bunyaviriadae and Orthomyxoviridae families, and proved that despite minimal sequence homology the structural similarities are striking. This strongly suggests an evolutionary common ancestor, which can possibly be shared with non-segmented negative-strand RNA viruses as well.

Made available in DSpace on 2014-06-11T19:23:01Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-02-24Bitstream added on 2014-06-13T20:29:39Z : No. of bitstreams: 1 ambrosio_dl_me_arafcf.pdf: 2442154 bytes, checksum: cc3386b51bef3a73071ee6043f88fc0e (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Universidade Estadual Paulista (UNESP) / Alguns fatores importantes no funcionamento das células eucarióticas correspondem à pequenos complexos de RNA e proteínas; essas partículas de ribonucleoproteínas (UsnRNPs) têm um papel essencial no processamento do pré-mRNA, principalmente durante o splicing (corte de íntrons e união de éxons). Embora as snRNPs estejam definidas em mamíferos, ainda não estão bem caracterizadas em certos tripanosomatídeos como o Trypanosoma cruzi. Assim, este trabalho propôs a caracterização molecular dos snRNAs (U2, U4, U5 e U6), por PCR e RT-PCR de formas epimastigotas de T. cruzi (cepa Y). Essas seqüências amplificadas foram clonadas, seqüenciadas e comparadas entre os tripanosomatídeos e o alinhamento múltiplo apresentou mais de 70% de identidade, exceto da U5 snRNA, que se mostrou menos conservada. Árvores filogenéticas mostraram a proximidade evolutiva dos snRNAs analisados em Trypanosoma brucei e Trypanosoma cruzi. As respectivas estruturas secundárias foram preditas, confirmando-se também as semelhanças com aquelas de T. brucei. O alinhamento das snRNAs de T. cruzi com as seqüências de Homo sapiens mostrou regiões únicas em U2, U4 e U5 snRNAs, nessa espécie, enquanto U6 mostrou-se fortemente conservada. Até o momento, ainda não foi possível a obtenção da seqüência completa de U1 snRNA de T. cruzi. / Some important factors in functioning of the eucariotic cells are the small complexes of RNA and proteins; these particles of ribonucleoproteins (UsnRNPs) have an essential role in the pre-mRNA processing, mainly during splicing (cut of introns and union of exons). Even though they are well defined in mammals, snRNPs are still not characterized in certain Trypanosomatids, as well, Trypanosoma cruzi. So, this work proposed the molecular characterization of the snRNAs (U2, U4, U5 and U6), by PCR and RT-PCR with T. cruzi epimastigote forms (Y strain). These amplified sequences were cloned, sequenced and compared among the Trypanosomatids and the multiple alignment presented more than 70% of identity, except for U5 snRNA, which showed less conserved. Phylogenetic trees showed the evolutionary proximity between the Trypanosoma brucei and Trypanosoma cruzi snRNAs analysed. The respective secondary structures were predicted and also confirmed similarity with T. brucei. The alignment of T. cruzi snRNAs with Homo sapiens sequences showed unique regions in U2, U4 and U5 snRNAs in this species, while U6 was strongly conserved. Until this moment, it was not still possible to obtain U1 snRNA of T. cruzi complete sequence.

Orientador: Regina Maria Barretto Cicarelli / Banca: Marcia Aparecida Silva Graminha / Banca: Lucile Maria Floeter-Winter / Resumo: Alguns fatores importantes no funcionamento das células eucarióticas correspondem à pequenos complexos de RNA e proteínas; essas partículas de ribonucleoproteínas (UsnRNPs) têm um papel essencial no processamento do pré-mRNA, principalmente durante o splicing (corte de íntrons e união de éxons). Embora as snRNPs estejam definidas em mamíferos, ainda não estão bem caracterizadas em certos tripanosomatídeos como o Trypanosoma cruzi. Assim, este trabalho propôs a caracterização molecular dos snRNAs (U2, U4, U5 e U6), por PCR e RT-PCR de formas epimastigotas de T. cruzi (cepa Y). Essas seqüências amplificadas foram clonadas, seqüenciadas e comparadas entre os tripanosomatídeos e o alinhamento múltiplo apresentou mais de 70% de identidade, exceto da U5 snRNA, que se mostrou menos conservada. Árvores filogenéticas mostraram a proximidade evolutiva dos snRNAs analisados em Trypanosoma brucei e Trypanosoma cruzi. As respectivas estruturas secundárias foram preditas, confirmando-se também as semelhanças com aquelas de T. brucei. O alinhamento das snRNAs de T. cruzi com as seqüências de Homo sapiens mostrou regiões únicas em U2, U4 e U5 snRNAs, nessa espécie, enquanto U6 mostrou-se fortemente conservada. Até o momento, ainda não foi possível a obtenção da seqüência completa de U1 snRNA de T. cruzi. / Abstract: Some important factors in functioning of the eucariotic cells are the small complexes of RNA and proteins; these particles of ribonucleoproteins (UsnRNPs) have an essential role in the pre-mRNA processing, mainly during splicing (cut of introns and union of exons). Even though they are well defined in mammals, snRNPs are still not characterized in certain Trypanosomatids, as well, Trypanosoma cruzi. So, this work proposed the molecular characterization of the snRNAs (U2, U4, U5 and U6), by PCR and RT-PCR with T. cruzi epimastigote forms (Y strain). These amplified sequences were cloned, sequenced and compared among the Trypanosomatids and the multiple alignment presented more than 70% of identity, except for U5 snRNA, which showed less conserved. Phylogenetic trees showed the evolutionary proximity between the Trypanosoma brucei and Trypanosoma cruzi snRNAs analysed. The respective secondary structures were predicted and also confirmed similarity with T. brucei. The alignment of T. cruzi snRNAs with Homo sapiens sequences showed unique regions in U2, U4 and U5 snRNAs in this species, while U6 was strongly conserved. Until this moment, it was not still possible to obtain U1 snRNA of T. cruzi complete sequence. / Mestre

A purificação de subunidades do vírus da raiva pode ser realizada por diferentes metodologias, uma vez purificadas estas subunidades podem ter diversas aplicações em métodos altamente específicos para o diagnóstico laboratorial e pesquisa da raiva. A obtenção de ribonucleoproteínas (RNP) do vírus da raiva pode ser realizada por meio de ultracentrifugação em gradiente de Cloreto de Césio (CsCl), porém este método possibilita a obtenção de RNP semi purificadas. Neste estudo foi utilizado o método de cromatografia de imunoafinidade para obtenção das RNP, os resultados obtidos foram satisfatórios quanto a um maior grau de pureza dessas proteínas, além de propiciar a otimização do processo e redução do tempo operacional, quando comparado a ultracentrifugação em gradiente de CsCl. / Purification of subunits of the rabies virus can be accomplished by different methodologies, once purified these subunits can have several applications in highly specific methods for diagnostic and research laboratory for rabies. Obtaining ribonucleoprotein (RNP) of rabies virus can be performed by ultracentrifugation in a Cesium Chloride (CsCl) gradient, but this method allows to obtain semi purified RNP. This study used the method of immunoaffnity chromatography to obtain the RNP; the results were satisfactory for a higher degree of purity of these proteins in addition to providing process optimization and reduced operating time compared to ultracentrifugation in a cesium chloride gradient.

京都大学 / 0048 / 新制・課程博士 / 博士(医科学) / 甲第22698号 / 医科博第113号 / 新制||医科||8(附属図書館) / 京都大学大学院医学研究科医科学専攻 / (主査)教授 竹内 理, 教授 椛島 健治, 教授 河本 宏 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

No description available.

No description available.