1,721,037 research outputs found
Detecção de Bunyavírus em flebotomíneos coletados em duas áreas do estado do Amazonas, Brasil
No full textArbovírus são um grupo de vírus que apresenta um ciclo biológico bastante
complexo, que envolve hospedeiros vertebrados suscetíveis e um ou mais
vetor artrópode. Os Phlebovirus são arbovírus da família Bunyaviridae transmitidos por insetos do gênero Lutzomyia no novo mundo e hlebotomus no velho mundo. Estes insetos são importantes vetores de doenças tropicais, como a leishmaniose e vem causando surtos de síndromes febris pelo mundo. Mesmo com uma vasta fauna de flebotomíneos na região Amazônica poucos estudos tiveram como objetivo principal detectar vírus nestes vetores. Em função do descrito anteriormente o presente trabalho teve como objetivo a detecção de Bunyavirus em flebotomíneos coletados na Reserva Florestal Adolpho Ducke, Manaus e no Ramal Nova Esperança, Manacapuru, Amazonas. Os flebotomíneos foram coletados em armadilhas de luz do tipo CDC adaptadas, além de coletas paralelas com aspiradores manuais. Os espécimes foram agrupados em pools, por sexo e armadilha, sendo posteriormente macerados. O material macerado foi inoculado em culturas de células VERO, seguido por técnicas de imunofluorescência indireta para família Bunyaviridae. As amostras positivas pela citometria de fluxo foram submetidas a ensaios moleculares, na tentativa de amplificação dos segmentos S e L de Bunyavirus. Dos 243 pools coletados foi identificada a presença de vírus da família Bunyaviridae em 17 pools através dos resultados obtidos pela citometria de fluxo, com base no deslocamento de células positivas que variaram entre 1,19 - 71,6%. Nesse projeto foi utilizado pela primeira vez um protocolo para Citometria de fluxo para Bunyavirus. Foram aplicadas também metodologias moleculares para detecção de Bunyavirus, seguidos de sequenciamento capilar e de Nova Geração. Entretanto, não foi possível a identificação viral por técnicas moleculares. As amostras estão armazenadas para experimentos futuros, na tentativa de elucidar questões como: a circulação de arbovírus de importância médica em flebotomíneos na Amazônia Ocidental Brasileira.The arbovirus are virus group with a complex life cycle, once vertebrate hosts as well as arthropod vectors are involved. The Phlebovirus are arboviruses of the Bunyaviridae family transmitted mainly by Lutzomyia insects in the new world and Phlebotomus in the old world. These insects are important vectors of tropical diseases, such as leishamaniasis, causing outbreaks of febrile syndromes worldwide. A large fauna of phlebotomus is observed in the Amazon region and a few studies aimed to detect virus at those vectors. The present study aimed to the detection of arboviruses in phlebotomus collected in the Reserva Florestal Adolpho Ducke, Manaus and at the Ramal Nova Esperança, Manacapuru, Amazonas. The phlebotomus were collected using adapted CDC light traps, including parallel collections with manual aspirators. Speciemens were grouped in pools by sex and trap, and subsequently macerated. The macerated samples were inoculated into VERO cells, following by indirect
immunofluorescence. The positives samples by flow cytometry were submitted to molecular assays, in order to amplify segments S and L of the Bunyavirus. Among the collected pools, 17 out of 243 were positive by flow cytometry, those samples presented displacement of positive cells within a range 1.19 – 71.6%. Also, molecular methods were applied for detection of Bunyavirus, following capillary and next generation sequencing. However, no virus was identified with this techniques. The samples are stored for futures studies, in order elucidate questions related to the presence of medical important arbovirus infecting phlebotomus at the Brazilian Western Amazon
Detecção de Bunyavírus em flebotomíneos coletados em duas áreas do estado do Amazonas, Brasil
No full textFundação Oswaldo Cruz, Instituto Leônidas & Maria Deane. Manaus, AM, Brasil.Arbovírus são um grupo de vírus que apresenta um ciclo biológico bastante
complexo, que envolve hospedeiros vertebrados suscetíveis e um ou mais
vetor artrópode. Os Phlebovirus são arbovírus da família Bunyaviridae transmitidos por insetos do gênero Lutzomyia no novo mundo e hlebotomus no velho mundo. Estes insetos são importantes vetores de doenças tropicais, como a leishmaniose e vem causando surtos de síndromes febris pelo mundo. Mesmo com uma vasta fauna de flebotomíneos na região Amazônica poucos estudos tiveram como objetivo principal detectar vírus nestes vetores. Em função do descrito anteriormente o presente trabalho teve como objetivo a detecção de Bunyavirus em flebotomíneos coletados na Reserva Florestal Adolpho Ducke, Manaus e no Ramal Nova Esperança, Manacapuru, Amazonas. Os flebotomíneos foram coletados em armadilhas de luz do tipo CDC adaptadas, além de coletas paralelas com aspiradores manuais. Os espécimes foram agrupados em pools, por sexo e armadilha, sendo posteriormente macerados. O material macerado foi inoculado em culturas de células VERO, seguido por técnicas de imunofluorescência indireta para família Bunyaviridae. As amostras positivas pela citometria de fluxo foram submetidas a ensaios moleculares, na tentativa de amplificação dos segmentos S e L de Bunyavirus. Dos 243 pools coletados foi identificada a presença de vírus da família Bunyaviridae em 17 pools através dos resultados obtidos pela citometria de fluxo, com base no deslocamento de células positivas que variaram entre 1,19 - 71,6%. Nesse projeto foi utilizado pela primeira vez um protocolo para Citometria de fluxo para Bunyavirus. Foram aplicadas também metodologias moleculares para detecção de Bunyavirus, seguidos de sequenciamento capilar e de Nova Geração. Entretanto, não foi possível a identificação viral por técnicas moleculares. As amostras estão armazenadas para experimentos futuros, na tentativa de elucidar questões como: a circulação de arbovírus de importância médica em flebotomíneos na Amazônia Ocidental Brasileira.The arbovirus are virus group with a complex life cycle, once vertebrate hosts as well as arthropod vectors are involved. The Phlebovirus are arboviruses of the Bunyaviridae family transmitted mainly by Lutzomyia insects in the new world and Phlebotomus in the old world. These insects are important vectors of tropical diseases, such as leishamaniasis, causing outbreaks of febrile syndromes worldwide. A large fauna of phlebotomus is observed in the Amazon region and a few studies aimed to detect virus at those vectors. The present study aimed to the detection of arboviruses in phlebotomus collected in the Reserva Florestal Adolpho Ducke, Manaus and at the Ramal Nova Esperança, Manacapuru, Amazonas. The phlebotomus were collected using adapted CDC light traps, including parallel collections with manual aspirators. Speciemens were grouped in pools by sex and trap, and subsequently macerated. The macerated samples were inoculated into VERO cells, following by indirect
immunofluorescence. The positives samples by flow cytometry were submitted to molecular assays, in order to amplify segments S and L of the Bunyavirus. Among the collected pools, 17 out of 243 were positive by flow cytometry, those samples presented displacement of positive cells within a range 1.19 – 71.6%. Also, molecular methods were applied for detection of Bunyavirus, following capillary and next generation sequencing. However, no virus was identified with this techniques. The samples are stored for futures studies, in order elucidate questions related to the presence of medical important arbovirus infecting phlebotomus at the Brazilian Western Amazon
Microevolução In Vitro do vírus Dengue, sorotipo-4: estudo de variações genéticas associadas ao aumento da competência viral
No full textO vírus Dengue (DENV) pertence à família Flaviviridae e ao gênero Flavivirus, sendo reconhecidos quatro sorotipos distintos denominados DENV-1 a DENV-4. Assim como os demais vírus RNA, o DENV exibe variação em suas sequências, com uma taxa de erro durante o ciclo de replicação estimada em 10-3 a 10-5 erros/nucleotídeo. Essas variações são observadas não só quando analisadas amostras de diferentes indivíduos, mas também dentro de um mesmo hospedeiro. Considerando a necessidade de uma maior compreensão dos mecanismos relacionados ao processo evolutivo do DENV e a emergência de subpopulações virais, o presente trabalho teve por objetivo avaliar a microevolução in vitro do vírus dengue, sorotipo-4, analisando a existência de variações genéticas associadas ao aumento da competência viral (viral fitness). Para tanto, uma amostra do DENV-4 denominada BrAM005/2011 foi inoculada
em células C6/36, sendo realizadas passagens seriadas do vírus nesta linhagem celular até a
passagem 25. Finalizadas as passagens, foi realizada extração do RNA viral e o cDNA foi
produzido utilizando iniciador específico para DENV-4. O genoma completo da amostra
BrAM005/2011 e das passagens 1, 5, 10, 15, 20 e 25 foi obtido pelo método Sanger utilizando
sequenciador automático ABI 3130 genetic analyzer e por meio de seq enciamento de nova
geração (NGS) utilizando a tecnologia Ion Torrent no equipamento Ion PGM™ System. Os
arquivos gerados após as reações de sequenciamento foram analisados utilizando o software
Geneious versão 7.1.7. A análise dos dados fornecidos pelo sequenciamento de Sanger mostrou
que no decorrer das passagens ocorreram duas mutações de nucleotídeos, sendo uma na região
codificante para a proteína do envelope que resultou na substituição de um resíduo de
aminoácido e outra na região da proteína NS1, porém esta foi uma mutação silenciosa. Os
resultados do NGS corroboraram com os obtidos pelo sequenciamento de Sanger e
apresentaram outras dezessete mutações não observadas pelo método anterior, sendo as mesmas
nas regiões codificantes para as proteínas E, NS1, NS2A, NS2B, NS3, NS4A, NS4B e NS5. Do
total de mutações observadas, seis delas resultaram em substituição de resíduo de aminoácido.
Considerando as mutações observadas, realizamos o estudo de cinética viral por RT-qPCR
utilizando o método de ΔΔCt que indicou um aumento do número de cópias de RNA viral,
dependente do tempo pós-infecção, tanto presente no sobrenadante de células infectadas quanto
no interior das células, indicando um possível aumento da competência viral. Outros estudos se
tornam necessários para confirmar se as mutações aqui encontradas também ocorrem em células
de mamíferos e em sistemas in vivo, de maneira a verificar se o aumento do fit ness viral
observado neste estudo se repete em outros sistemas.Dengue virus (DENV) belongs to the family Flaviviridae and the genus Flavivirus, being recognized as four distinct serotypes termed DENV-1 to DENV-4. Like other RNA viruses, DENV displays variation in their sequences, with an error rate during replication cycle estimated at 10-3 to 10-5 errors / nucleotide. These variations are observed not only when samples from different individuals are analyzed, but also within the same host. Considering the need for a better understanding of related mechanisms of DENV evolutionary process and the emergence of viral subpopulations, this study aimed to evaluate the in vitro microevolution of dengue virus serotype-4, analyzing the existence of genetic variations associated with increased viral fitness. For this purpose, a sample of DENV-4 called BrAM005/2011 was inoculated in C6/36 cells and 25 serial passages were performed. After these passages, viral RNA extraction
was performed and the cDNA was produced using a specific DENV-4 primer. The full-length genome of the sample BrAM005/2011 and passages 1, 5, 10, 15, 20 and 25 were obtained by the Sanger method using the ABI 3130 Genetic Analyzer and by Next-Generation Sequencing (NGS) using the Ion Torrent technology. The files generated after the sequencing reactions were analyzed using Geneious software version 7.1.7. The analysis of the data provided by the Sanger sequencing has shown that during the 25 passages, two nucleotide mutations occurred, one in the region which encodes for the envelope protein, resulting in the substitution of an amino acid residue T501P, and other silent mutation at NS1 gene. The results of NGS corroborate those obtained by Sanger sequencing. Moreover, seventeen other m tations not
previously observed, being the same in the coding regions for proteins E, NS1, NS2A, NS2B, NS3, NS4A, NS4B and NS5. Of the total observed mutations, six of them led to residue substitution. Considering the observed amino acids substitutions, we conducted a study of viral kinetics by RT-qPCR using the ΔΔCt method which indicated a time-dependent increase in the number of copies of viral RNA present in both the supernatant or inside the infected cells, indicating a possible increase of the viral fitness. Other studies are necessary to confirm if the mutations described here also occurs in mammalian cells or in vivo systems, as well as to verify if the observed increase in viral fitness occurs in other systems
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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