963 resultados para B Virus
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Hepatitis C virus (HCV) genotype 3a accounts for similar to 80% of HCV infections in Pakistan, where similar to 10 million people are HCV-infected. Here, we report analysis of the genetic heterogeneity of HCV NS3 and NS5b subgenomic regions from genotype 3a variants obtained from Pakistan. Phylogenetic analyses showed that Pakistani genotype 3a variants were as genetically diverse as global variants, with extensive intermixing. Bayesian estimates showed that the most recent ancestor for genotype 3a in Pakistan was last extant in similar to 1896-1914 C.E. (range: 1851-1932). This genotype experienced a population expansion starting from similar to 1905 to similar to 1970 after which the effective population leveled. Death/birth models suggest that HCV 3a has reached saturating diversity with decreasing turnover rate and positive extinction. Taken together, these observations are consistent with a long and complex history of HCV 3a infection in Pakistan. Published by Elsevier B.V.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Câncer cervical é o segundo tipo mais comum em mulheres no mundo. Estudos apontam que a presença de certos tipos do HPV desempenha um papel central na formação do câncer. Apesar do grande sucesso da prevenção do câncer uterino com vacinas, o uso de produtos naturais para o tratamento de doenças é crescente e de grande importância econômica. Alcalóides guanidínicos isolados de Pterogyne nitens representam uma potencial fonte de novos tratamentos. O objetivo geral desse trabalho foi avaliar a atividade apoptótica induzida em células de carcinoma cervical infectadas (SiHa) e não infectadas pelo HPV (C33-A), tratadas com nitensidinas A e B, isoladas de folhas de Pterogyne nitens Tul. A citotoxicidade dos alcalóides foi avaliada utilizando o método de MTT. Para avaliar quantitativamente a apoptose e necrose celular, foi executado o ensaio de Anexina V por citometria de fluxo. Ambas as substâncias, nitensidinas A e B, apresentaram efeito citotóxico concentração-resposta em ambas as linhagens testadas (SiHa e C33A) e nos dois tempos de tratamento (24 horas e 48 horas). Não foi observada significância estatística quando comparados os perfis de ação citotóxica das duas substâncias em teste (nitensidinas A e B), em nenhuma das linhagens testadas (SiHa e C33A) e em nenhum dos dois tempos de tratamento (24 horas e 48 horas). Ambas as substâncias, nitensidina A e nitensidina B, apresentaram efeito indutor de apoptose precoce e, em menor número, de apoptose tardia/ necrose, em ambas as linhagens testadas (SiHa e C33A) e nos dois tempos de tratamento (24 horas e 48 horas)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Grapevine virus A (GVA), a flexible filament of approximately 800 nm in length is composed of capsid subunits that spontaneously assembles around a positive sense genomic RNA. In addition to encapsidation, plant viruses capsid proteins (CPs) participate in other processes throughout infection and GVA CP is involved in cell-to-cell translocation of the virus. A protocol was developed to obtain low-molecular weight GVA-CP that is not prone to aggregation and spontaneous assembly and this was characterized by circular dichroism and dynamic light scattering. These results indicate the suitably of GVA-CP for X-ray crystallographic and NMR studies that should lead to the elucidation of the first three-dimensional structure of a flexible filamentous virus from the Betaflexiviridae family.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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EQUINE influenza A virus (EIV) is a highly infectious respiratory pathogen of horses (Hannant and Mumford 1996, Palese and Shaw 2007). The illness is characterized by an abrupt onset of fever, depression, coughing and nasal discharge, and is often complicated by secondary bacterial infections that can lead to pneumonia and death. Two subtypes of EIV, H3N8 and H7N7, have been isolated. The H7N7 subtype was first isolated from a horse in Czechoslovakia in 1956 (Prague/56), and the H3N8 subtype was first isolated from a horse in Miami in 1963 (Sovinova and others 1958, Waddell and others 1963). The last confirmed outbreak of H7N7 occurred in 1979, and this subtype is now considered to be either extinct or circulating at low levels in a few geographical areas (Ismail and others 1990, Webster 1993, Singh 1994, Madic and others 1996, van Maanen and Cullinane 2002). The H3N8 subtype is a common cause of disease in horses worldwide, particularly in areas where vaccination is not routinely performed (Paillot and others 2006).
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The pathogenesis of South American and North American myxoma viruses was examined in two species of North American lagomorphs, Sylvilagus nuttallii (mountain cottontail) and Sylvilagus audubonii (desert cottontail) both of which have been shown to have the potential to transmit the South American type of myxoma virus. Following infection with the South American strain (Lausanne, Lu), S. nuttallii developed both a local lesion and secondary lesions on the skin. They did not develop the classical myxomatosis seen in European rabbits (Oryctolagus cuniculus). The infection at the inoculation site did not resolve during the 20-day time course of the trial and contained transmissible virus titres at all times. In contrast, S. audubonii infected with Lu had very few signs of disseminated infection and partially controlled virus replication at the inoculation site. The prototype Californian strain of myxoma virus (MSW) was able to replicate at the inoculation site of both species but did not induce clinical signs of a disseminated infection. In S. audubonii, there was a rapid response to MSW characterized by a massive T lymphocyte infiltration of the inoculation site by day 5. MSW did not reach transmissible titres at the inoculation site in either species. This might explain why the Californian myxoma virus has not expanded its host-range in North America.