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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Desenvolvimento e aplicação de RT-PCR em tempo real para Vesiculovirus brasileiros / Development and application of a real-time RT-PCR for brazilian Vesiculovirus

Tolardo, Aline Lavado 06 February 2015 (has links)
Os Vesiculovirus são um gênero de vírus de RNA da família Rhabdoviridae que inclui os sorotipos Carajás, Cocal, Marabá, Piry, Alagoas e Indiana. Estes são causadores de estomatite vesicular em ruminantes e doença febril humana no Brasil. As vesiculoviroses e suas epidemiologias são pouco conhecidas em seres humanos. Ainda, os Vesiculovirus (VSV) são pouco diagnosticados no homem e em animais pela escassez de métodos laboratoriais diagnósticos. Por isso, objetivamos neste trabalho desenvolver e testar uma RT-PCR em tempo real, pelo método SYBR Green, visando à detecção de VSV brasileiros. Primers que amplificam parte do gene da proteína G dos VSV foram utilizados no teste o qual mostrou-se capaz de detectar genomas dos VSV Piry, Indiana, Alagoas e Carajás. O método foi usado para testar amostras séricas de pacientes com doença febril aguda, de bovinos, de equinos e de macerados de artrópodos. A RT-PCR em tempo real mostrou-se 100 vezes mais sensível que a RT-PCR convencional para Vesiculovirus e também, permitiu detectar até 10 cópias de RNA do vírus Piry. Ainda, a RT-PCR em tempo real para Vesiculovirus mostrou-se capaz de diagnosticar e quantificar o VSV Alagoas nas amostras séricas de bovinos e de equinos. Portanto, a RT-PCR em tempo real desenvolvida neste trabalho, provavelmente, será muito útil no diagnóstico e também, em futuras pesquisas, que permitirão ampliar o conhecimento epidemiológico, ainda pouco conhecido, sobre os Vesiculovirus. / The Vesiculovirus is a Rhabdoviridae family genre of RNA virus that includes serotypes Carajás, Cocal, Maraba, Piry, Alagoas and Indiana. These are causes of vesicular stomatitis in ruminants and human febrile illness in Brazil. The vesiculoviroses and its epidemiology are little known in humans. Still, Vesiculovirus (VSV) are poorly diagnosed in humans and laboratory animals by the lack of diagnostic methods. Therefore, we proposed in this work to develop and test a real-time RT-PCR by SYBR Green method, focusing on the detection of Brazilian VSV. Primers that amplify part of the VSV G protein gene were used in the test which proved capable of detecting genomes of VSV Piry, Indiana, Alagoas and Carajás. The method was used to test serum samples from patients with acute febrile disease, cattle, horses and macerated arthropods. Real time RT-PCR showed to be 100 times more sensitive than conventional RT-PCR for Vesiculovirus and also was possible to detect up to 10 RNA copies of the Piry virus. Also, the real-time RT-PCR for Vesiculovirus proved able to diagnose and quantify Alagoas VSV in serum samples from cattle and horses. Therefore, the real-time RT-PCR developed in this work will probably be very useful in the diagnosis and in future research, which will increase the epidemiological knowledge, as it is still little known about the Vesiculovirus.
2

Desenvolvimento e aplicação de RT-PCR em tempo real para Vesiculovirus brasileiros / Development and application of a real-time RT-PCR for brazilian Vesiculovirus

Aline Lavado Tolardo 06 February 2015 (has links)
Os Vesiculovirus são um gênero de vírus de RNA da família Rhabdoviridae que inclui os sorotipos Carajás, Cocal, Marabá, Piry, Alagoas e Indiana. Estes são causadores de estomatite vesicular em ruminantes e doença febril humana no Brasil. As vesiculoviroses e suas epidemiologias são pouco conhecidas em seres humanos. Ainda, os Vesiculovirus (VSV) são pouco diagnosticados no homem e em animais pela escassez de métodos laboratoriais diagnósticos. Por isso, objetivamos neste trabalho desenvolver e testar uma RT-PCR em tempo real, pelo método SYBR Green, visando à detecção de VSV brasileiros. Primers que amplificam parte do gene da proteína G dos VSV foram utilizados no teste o qual mostrou-se capaz de detectar genomas dos VSV Piry, Indiana, Alagoas e Carajás. O método foi usado para testar amostras séricas de pacientes com doença febril aguda, de bovinos, de equinos e de macerados de artrópodos. A RT-PCR em tempo real mostrou-se 100 vezes mais sensível que a RT-PCR convencional para Vesiculovirus e também, permitiu detectar até 10 cópias de RNA do vírus Piry. Ainda, a RT-PCR em tempo real para Vesiculovirus mostrou-se capaz de diagnosticar e quantificar o VSV Alagoas nas amostras séricas de bovinos e de equinos. Portanto, a RT-PCR em tempo real desenvolvida neste trabalho, provavelmente, será muito útil no diagnóstico e também, em futuras pesquisas, que permitirão ampliar o conhecimento epidemiológico, ainda pouco conhecido, sobre os Vesiculovirus. / The Vesiculovirus is a Rhabdoviridae family genre of RNA virus that includes serotypes Carajás, Cocal, Maraba, Piry, Alagoas and Indiana. These are causes of vesicular stomatitis in ruminants and human febrile illness in Brazil. The vesiculoviroses and its epidemiology are little known in humans. Still, Vesiculovirus (VSV) are poorly diagnosed in humans and laboratory animals by the lack of diagnostic methods. Therefore, we proposed in this work to develop and test a real-time RT-PCR by SYBR Green method, focusing on the detection of Brazilian VSV. Primers that amplify part of the VSV G protein gene were used in the test which proved capable of detecting genomes of VSV Piry, Indiana, Alagoas and Carajás. The method was used to test serum samples from patients with acute febrile disease, cattle, horses and macerated arthropods. Real time RT-PCR showed to be 100 times more sensitive than conventional RT-PCR for Vesiculovirus and also was possible to detect up to 10 RNA copies of the Piry virus. Also, the real-time RT-PCR for Vesiculovirus proved able to diagnose and quantify Alagoas VSV in serum samples from cattle and horses. Therefore, the real-time RT-PCR developed in this work will probably be very useful in the diagnosis and in future research, which will increase the epidemiological knowledge, as it is still little known about the Vesiculovirus.
3

Development of Vesiculovirus-based Therapeutics for Acute Leukemia

Conrad, David Paul January 2014 (has links)
Outcomes for most patients with acute leukemia remain dismal. In-vitro, vesiculovirus members induced rapid apoptosis of acute leukemia cells. Intravenous injection of lymphoblastic leukemia cells infected ex-vivo with attenuated Vesicular Stomatitis Virus or Maraba Virus followed by gamma-irradiation, controlled leukemic progression in murine recipients. Essential properties of this autologous vaccine [immunotherapy by Leukemia-Oncotropic Virus (iLOV)] and the host’s immune system were characterized. iLOV durability was restricted to the leukemia used to manufacture the vaccine. At administration, virion cell-entry was required but vesiculovirus lifecycle completion was not essential. Apoptotic or necrotic leukemia cells, with/without co-injection of virus, were ineffective vaccines. Similarly ineffective were leukemia cells activated by, or injected with, Toll-like receptor agonists. Naïve recipients of adoptive splenocyte transfer from vaccine-treated immunocompetent donors were protected from leukemic challenge. Efficacy was notably diminished following matched allogeneic bone marrow transplantation; this correlated with isolated depletion of cytotoxic T-cells. iLOV was ineffective in athymic mice. Taken together, iLOV therapy relies on immediate spaciotemporal interactions between infected-dead/dying leukemia cells and the immune system; this promotes adaptive anti-tumor responses. Clinical translation could target patients in remission to control relapse. During the above I discovered that under specific conditions, live vesiculovirus exposed to a precise window of UV fluence reproducibly generates unique “non-replicating rhabdovirus-derived particles” (NRRPs) that maintain cell-entry and cytopathic properties. A gamut of leukemia cells, including multidrug-resistant blasts, underwent rapid NRRPs-induced apoptosis. Normal cell lines and healthy bone marrow mononuclear cells were resistant, in part through interferon-mediated signaling responses. Administering NRRPs intravenously was curative in a murine acute leukemia model, versus uniform disease progression using maximal tolerated dose of replicating virus. Serum levels of an array of immunomodulatory cytokines were significantly elevated after injection of NRRPs. iLOV prepared with NRRPs protected recipients from otherwise lethal leukemia. Intracranial administration of NRRPs proved nonlethal as opposed to neurotoxic live vesiculovirus. Following treatment, neutralizing antibodies were diminished with NRRPs compared to replicating virus. Together, NRRPs exhibit enhanced therapeutic index over replication-competent vesiculovirus. Leukemocidal activity of NRRPs is exerted through a plurality of immune-related and direct cytotoxic effects. This novel approach now extends vesiculovirus-based therapeutics into upfront treatment for acute leukemia.
4

Resposta antiviral em células LL5 de Lutzomyia longipalpiscomparativo entre infecção por vírus da Estomatite Vesicular (VSV) e dsRNA

Carvalho, Eudislaine Fonseca de January 2013 (has links)
Made available in DSpace on 2016-04-20T12:39:28Z (GMT). No. of bitstreams: 2 eudislaine_carvalho_ioc_mest_2013.pdf: 1777151 bytes, checksum: 5c17debede158ac9bc7692a3a408b4ba (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2013 / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Rio de Janeiro, RJ, Brasil / As doenças transmitidas por insetos vetores são de grande importância para saúde pública. No Brasil, as principais doenças compreendem a malária, doença de Chagas, leishmaniose, dengue e febre amarela. O inseto vetor flebotomíneo é o principal transmissor da leishmaniose. Porém, também são vetores de outros agentes patogênicos e hospedeiros de diversos outros microrganismos, tais como bactérias, fungos e arbovírus. Os arbovírus são biologicamente transmitidos entre hospedeiros vertebrados por insetos hematófagos. Sua distribuição ocorre de forma global, porém a maioria é encontrada em áreas tropicais, onde as condições climáticas permitem a transmissão durante todo o ano. Os arbovírus do gênero Vesiculovírus, Orbivírus e Phlebovírus são os mais comuns encontrados em flebotomíneos. Além destes gêneros isolados do próprio inseto, os vírus Mayaro e do Oeste do Nilo também são capazes de infectar uma linhagem celular (LL5) da espécie Lutzomyia longipalpis. A resposta imune é essencial para os artrópodes sobreviverem aos agentes patogênicos, as principais vias envolvidas na resposta imune de artrópodes incluem a via Imd, Toll e Jak/Stat. Os artrópodes possuem diversos mecanismos contra infecção viral, entre eles a apoptose, a via de RNA de interferência (RNAi) e a autofagia. O mecanismo utilizado pela maioria dos vetores é o silenciamento da expressão gênica dos vírus através da via do RNAi Esta via é amplamente conservada em diferentes espécies e se baseia na complementariedade do RNA dupla fita (dsRNA) para degradação de mRNA, sendo assim uma resposta sequência específica. A via Jak/Stat também tem sido associada à resposta antiviral. O gene responsivo a vírus, Vago, atua como um interferon like e é responsável pela ativação de Jak/Stat. A única descrição que existe sobre a resposta antiviral em flebotomíneos é uma resposta inespecífica, que é ativada por qualquer dsRNA. Como não se tem conhecimento preciso dos mecanismos de defesa antiviral neste inseto, nosso trabalho avalia o papel de diferentes componentes do sistema imune no mecanismo de defesa antiviral em células LL5. Realizamos dois modelos eficientes de infecção com vírus VSV e mimetização da infecção, através de transfecção de poly I:C (dsRNA), em células LL5 e em células Aag2 de A. aegypti para o estudo da resposta antiviral. Após a infecção ou transfecção de dsRNA avaliamos o perfil de expressão de alguns genes da resposta antiviral: Dicer 2, Vago, Stat, Defensina e Atg18. LL5 apresentou uma resposta a infecção com VSV diferente das células Aag2, sendo que nestas células a dsRNA é capaz de ativar uma resposta antiviral contra VSV, diferentemente das células LL5. Sugerimos também que a resposta antiviral de LL5 contra infecção com VSV ocorra através do mecanismo de autofagia, pois, outros genes clássicos da via de RNAi e Jak/Stat (Dicer, Vago e Stat) não foram modulados positivamente neste modelo / Insect-borne diseases have a great importance in public health. In Brazil, the main diseases transmitted by insects include malaria, Chagas disease, leishmaniasis, dengue and yellow fever. Sandflies are the main vectors of leishmania parasites, but may also harbors and even transmit other pathogens such as bacteria, fungi and arbovirus. The arboviruses are biologically transmitted between vertebrate hosts by hematophagous insects. Its distribution occurs globally, but mostly in tropical areas, where climatic conditions may allow transmission throughout the year. The arbovirus of the genus Vesiculovirus, Orbivirus and Phlebovirus are commonly found in sandflies. In addition, the Mayaro virus and West Nile virus are also able of infecting Lutzomyia longipalpis cell line (LL5). The immune response is essential for arthropods to survive the pathogens infection and the major pathways involved in this immune response are Imd, Toll and Jak/Stat pathways. The arthropods have diverse mechanisms against viral infection, including apoptosis, the RNA interference pathway (RNAi) and autophagy. The mechanism used by most of the vectors is the silencing of gene expression through the RNAi pathway. This pathway is conserved among different species and is based on degradation of mRNA complementary to double-strand RNA (dsRNA), thus being a sequence-specific response. The Jak/Stat pathway has also been associated with antiviral response The virus responsive gene, Vago, acts as an interferon-like and is responsible for activation of Jak/Stat. The only information regarding the antiviral response in sandflies is a non-specific response, which is activated by any dsRNA. Since there is no precise knowledge of the antiviral defense mechanism in this insect, our study evaluated the role of different components of the immune system in antiviral defense mechanism in LL5 cells. We used two efficient models of infection with VSV virus and mimicking the infection by transfection of poly I:C (dsRNA) in LL5 cells and Aag2 cells of Aedes aegypti to study the antiviral response. After infection or transfection of dsRNA we evaluated the expression profile of some genes related to antiviral response: Dicer 2, Vago, Stat and Atg18. LL5 and Aag2 showed different responses to VSV infection, and in Aag2 cells the dsRNA is able to activate and antiviral response against VSV, differently in LL5 cells. We also suggest that the antiviral response of LL5 against VSV infection occurs through the mechanism of autophagy, because other classical genes of the RNAi and Jak/Stat pathways were not positively modulated in this model
5

Caracterização genômica e evolutiva de vírus zoonóticos nas Américas / Genomic and evolutionary characterization of zoonotic viruses in the Americas

Souza, William Marciel de 10 November 2017 (has links)
O sequenciamento de alto desempenho, pela redução dos custos nos últimos anos, vem sendo cada vez mais utilizado para prospectar e identificar vírus. Estes métodos são extremamente mais sensíveis que outros métodos moleculares, e capazes de sequenciar genomas virais sem conhecimento prévio, clonagem ou isolamento. Neste estudo, utilizamos o sequenciamento de alto desempenho para conhecer, e caracterizar genomas completos de arbovírus isolados nas Américas, incluindo a prospecção de vírus em amostras de pequenos mamíferos do estado de São Paulo, Brasil. Assim, sequenciamos e caracterizamos 44 Bunyavirales, 35 no gênero Orthobunyavirus, família Peribunyaviridae, oito no gênero Phlebovirus, família Phenuiviridae, e um orthonairovírus, família Nairoviridae. Entre os Bunyavirales identificamos uma provável nova estratégia de codificação da proteína não estrutural do segmento pequeno, e ainda identificados sete vírus que são reassortants naturais. Caracterizamos o genoma completo do vesiculovírus Piry, determinando sua relação filogenética com arbovírus pertencentes ao gênero Vesiculovirus, família Rhabdoviridae. Prospectamos novos vírus, os quais incluímos em três famílias, Parvoviridae, Anelloviridae e Hepeviridae. Na família Parvoviridae, identificamos 20 chapparvovírus endógenos e exógenos, oriundos de grande diversidade de hospedeiros vertebrados e invertebrados, e que representam uma nova subfamília, a Chapparvovirinae. Também, descrevemos onze novas espécies de Anelloviridae em roedores silvestres e marsupiais, fornecendo importantes informações sobre a diversidade, a taxonomia, e ainda ampliamos a gama de hospedeiros de anellovírus conhecidos. Por fim, identificamos e caracterizamos uma nova espécie de Orthohepevirus de roedores Sigmodontinae, nomeada \"Orthohepevirus E\". Acreditamos que estamos a fornecer relevantes informações sobre genômica, epidemiologia molecular, evolução e taxonomia de 45 arbovírus americanos, bem como sobre 13 novas espécies virais encontradas em pequenos mamíferos. Tais informações deverão dar subsídios para múltiplos futuros estudos visando compreender a importância destes novos vírus e a desenvolver métodos diagnósticos. / In last years, high-throughput sequencing (HTS) has been cost-effective and increasingly used for prospection and identification of viruses. These methods are extremely more sensitive than other molecular methods and are capable of sequencing viral genomes without prior knowledge, cloning or isolation. In this study, we used HTS approach to identify and characterize complete genomes of arbovirus isolated in the Americas, as well as viral prospection in samples of small mammals from São Paulo State, Brazil. Thus, we sequenced and characterized 44 viruses from Bunyavirales order, including 35 in Orthobunyavirus genus, family Peribunyaviridae, eight in Phlebovirus genus, family Phenuiviridae, and one in Orthonairovirus genus, family Nairoviridae. Among the Bunyavirales we identified a novel putative strategy for encoding the non-structural protein of the small segment, as well as we identified seven viruses that are natural reassortants. Also, we characterized the complete genome of the Piry vesiculovirus, determining its phylogenetic relationship with arboviruses belonging to the Vesiculovirus genus, family Rhabdoviridae. On the other hand, we have prospected novel viruses, which included in three families, Parvoviridae, Anelloviridae, and Hepeviridae. In the Parvoviridae family, we identified 20 endogenous and exogenous chapparvoviruses from a broad diversity of vertebrate and invertebrate hosts, representing a new subfamily, the Chapparvovirinae. Also, we have described eleven new species of Anelloviridae in wild rodents and marsupials, providing important information on diversity, taxonomy and even broadening the range of known anelloviruses hosts. Finally, we identified and characterized a novel species of orthohepevirus in Sigmodontinae rodent, named \"Orthohepevirus E\". We believe that we are providing relevant relevant on genomics, molecular epidemiology, evolution and taxonomy of 45 American arboviruses, as well as on 13 new viral species found in small mammals. Thus, these informations should provide support for multiple future studies to understand the importance of these new viruses, as well as to develop diagnostic methods.
6

Caracterização genômica e evolutiva de vírus zoonóticos nas Américas / Genomic and evolutionary characterization of zoonotic viruses in the Americas

William Marciel de Souza 10 November 2017 (has links)
O sequenciamento de alto desempenho, pela redução dos custos nos últimos anos, vem sendo cada vez mais utilizado para prospectar e identificar vírus. Estes métodos são extremamente mais sensíveis que outros métodos moleculares, e capazes de sequenciar genomas virais sem conhecimento prévio, clonagem ou isolamento. Neste estudo, utilizamos o sequenciamento de alto desempenho para conhecer, e caracterizar genomas completos de arbovírus isolados nas Américas, incluindo a prospecção de vírus em amostras de pequenos mamíferos do estado de São Paulo, Brasil. Assim, sequenciamos e caracterizamos 44 Bunyavirales, 35 no gênero Orthobunyavirus, família Peribunyaviridae, oito no gênero Phlebovirus, família Phenuiviridae, e um orthonairovírus, família Nairoviridae. Entre os Bunyavirales identificamos uma provável nova estratégia de codificação da proteína não estrutural do segmento pequeno, e ainda identificados sete vírus que são reassortants naturais. Caracterizamos o genoma completo do vesiculovírus Piry, determinando sua relação filogenética com arbovírus pertencentes ao gênero Vesiculovirus, família Rhabdoviridae. Prospectamos novos vírus, os quais incluímos em três famílias, Parvoviridae, Anelloviridae e Hepeviridae. Na família Parvoviridae, identificamos 20 chapparvovírus endógenos e exógenos, oriundos de grande diversidade de hospedeiros vertebrados e invertebrados, e que representam uma nova subfamília, a Chapparvovirinae. Também, descrevemos onze novas espécies de Anelloviridae em roedores silvestres e marsupiais, fornecendo importantes informações sobre a diversidade, a taxonomia, e ainda ampliamos a gama de hospedeiros de anellovírus conhecidos. Por fim, identificamos e caracterizamos uma nova espécie de Orthohepevirus de roedores Sigmodontinae, nomeada \"Orthohepevirus E\". Acreditamos que estamos a fornecer relevantes informações sobre genômica, epidemiologia molecular, evolução e taxonomia de 45 arbovírus americanos, bem como sobre 13 novas espécies virais encontradas em pequenos mamíferos. Tais informações deverão dar subsídios para múltiplos futuros estudos visando compreender a importância destes novos vírus e a desenvolver métodos diagnósticos. / In last years, high-throughput sequencing (HTS) has been cost-effective and increasingly used for prospection and identification of viruses. These methods are extremely more sensitive than other molecular methods and are capable of sequencing viral genomes without prior knowledge, cloning or isolation. In this study, we used HTS approach to identify and characterize complete genomes of arbovirus isolated in the Americas, as well as viral prospection in samples of small mammals from São Paulo State, Brazil. Thus, we sequenced and characterized 44 viruses from Bunyavirales order, including 35 in Orthobunyavirus genus, family Peribunyaviridae, eight in Phlebovirus genus, family Phenuiviridae, and one in Orthonairovirus genus, family Nairoviridae. Among the Bunyavirales we identified a novel putative strategy for encoding the non-structural protein of the small segment, as well as we identified seven viruses that are natural reassortants. Also, we characterized the complete genome of the Piry vesiculovirus, determining its phylogenetic relationship with arboviruses belonging to the Vesiculovirus genus, family Rhabdoviridae. On the other hand, we have prospected novel viruses, which included in three families, Parvoviridae, Anelloviridae, and Hepeviridae. In the Parvoviridae family, we identified 20 endogenous and exogenous chapparvoviruses from a broad diversity of vertebrate and invertebrate hosts, representing a new subfamily, the Chapparvovirinae. Also, we have described eleven new species of Anelloviridae in wild rodents and marsupials, providing important information on diversity, taxonomy and even broadening the range of known anelloviruses hosts. Finally, we identified and characterized a novel species of orthohepevirus in Sigmodontinae rodent, named \"Orthohepevirus E\". We believe that we are providing relevant relevant on genomics, molecular epidemiology, evolution and taxonomy of 45 American arboviruses, as well as on 13 new viral species found in small mammals. Thus, these informations should provide support for multiple future studies to understand the importance of these new viruses, as well as to develop diagnostic methods.
7

Implementation of molecular detection techniques in the field of veterinary virology : with special reference to the ligation-based methodologies /

Gyarmati, Péter, January 2008 (has links) (PDF)
Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2008. / Härtill 4 uppsatser.

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