1,720,962 research outputs found
Estudio de los determinantes moleculares involucrados en la traducción de los ARN mensajeros de arenavirus
Full text linkThe genome of Tacaribe virus (TCRV), prototype of the New World\narenaviruses, encodes four proteins which are expressed from subgenomic\nmessenger RNAs (mRNAs). These mRNAs contain Cap structure at the 5? end,\nand lack a 3? poly(A) tail, exhibiting a 3? untranslated region (UTR) predicted to\nform a stable secondary hairpin structure with a suspected role in translation.\nTo analyze the contribution of non-coding sequences to TCRV mRNAs\ntranslation, we generated a synthetic transcript mimicking the TCRV\nNucleoprotein (NP) mRNA, which contains the Firefly Luciferase (FLUC) open\nreading frame. Mutant mRNAs were designed to carry modifications in either\nthe 5? or the 3? UTR. Translation from these virus-like mRNAs in transfected\ncells was evidenced by FLUC activity, along with determination of mRNA\nstability by qPCR. Taken together, the data suggested that the predicted hairpin\nstability at the 3?UTR and/or its G/C content play a modulatory role in\ntranslation. In addition, both the sequence neighboring the stop codon in the 3?\nUTR, and the 5' UTR were found to contain sequence or structure elements\nwhich stimulate translation. It was also observed that the presence of NP or\nother viral proteins do not affect translation, and that this process requires the\neukaryotic translation factor eIF4GI. Also, this study succeeded in developing a\nreverse genetic system that directs the generation of recombinant TCRV, a\nvaluable tool that will allow performing mechanistic studies in the context of a\nviral infection.Fil: Foscaldi, Sabrina Andrea. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Buenos Aires, ArgentinaLas proteínas del virus Tacaribe (TCRV), prototipo de los arenavirus del\nNuevo Mundo, se expresan a partir de ARN mensajeros subgenómicos\n(ARNm), los cuales contienen estructura Cap en su extremo 5?, carecen de cola\nde poli(A) en el extremo 3?, pero presentan una región 3? no codificante que\npuede potencialmente formar una estructura secundaria de horquilla (hairpin II),\ncon un presunto papel en la traducción. Para analizar la contribución de las\nsecuencias no codificantes en la traducción de los ARNm de TCRV, se generó\nun transcripto sintético que imita al ARNm de la Nucleoproteina viral (NP), y\nque contiene el gen de la Luciferasa de luciérnaga (FLUC). Además, se\ngeneraron transcriptos mutantes con modificaciones en la secuencia 3' o 5? no\ntraducible. La eficiencia de traducción de esos transcriptos en células\ntransfectadas fue evidenciada mediante la determinación de la actividad FLUC,\njunto con la determinación de su estabilidad mediante PCR cuantitativa. En\nconjunto, los datos sugieren que la estructura secundaria en la secuencia\nhairpin II y/o su contenido de residuos G/C juegan un papel modulador en la\ntraducción. Por otra parte, tanto la secuencia proximal al codón de terminación\nen la región 3? no traducible, como la región 5' no codificante contienen motivos\nde secuencia o estructura que estimulan la traducción. Se encontró que la\npresencia de NP u otras proteínas virales no afectan la eficiencia de traducción,\ny que este proceso requiere del factor de traducción eucariota eIF4GI. Además,\nen este trabajo se desarrolló un sistema de genética inversa que dirige la\ngeneración de TCRV recombinante, una herramienta valiosa que permitirá la\nrealización de estudios mecanísticos en el contexto de la infección viral.Ciencias BiológicasDoctora de la Universidad de Buenos Aires en Farmacia y Bioquímic
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
Differential contribution of Tacaribe arenavirus Nucleoprotein N-terminal and C-terminal residues to nucleocapsid functional activity
Full text linkThe arenavirus nucleoprotein (NP) is the main protein component of viral nucleocapsids and is strictly required for viral genome replication mediated by the L polymerase. Homo-oligomerization of NP is presumed to play an important role in nucleocapsid assembly, albeit the underlying mechanism and the relevance of NP-NP interaction in nucleocapsid activity are still poorly understood. Here, we evaluate the contribution of the New World Tacaribe virus (TCRV) NP self-interaction to nucleocapsid functional activity. We show that alanine substitution of N-terminal residues predicted to be available for NP-NP interaction strongly affected NP self-association, as determined by coimmunoprecipitation assays, produced a drastic inhibition of transcription and replication of a TCRV minigenome RNA, and impaired NP binding to RNA. Mutagenesis and functional analysis also revealed that, while dispensable for NP self-interaction, key amino acids at the C-terminal domain were essential for RNA synthesis. Furthermore, mutations at these C-terminal residues rendered NP unable to bind RNA both in vivo and in vitro but had no effect on the interaction with the L polymerase. In addition, while all oligomerization-defective variants tested exhibited unaltered capacities to sustain NP-L interaction, NP deletion mutants were fully incompetent to bind L, suggesting that, whereas NP self-association is dispensable, the integrity of both the N-terminal and C-terminal domains is required for binding the L polymerase. Overall, our results suggest that NP self-interaction mediated by the N-terminal domain may play a critical role in TCRV nucleocapsid assembly and activity and that the C-terminal domain of NP is implicated in RNA binding. IMPORTANCE: The mechanism of arenavirus functional nucleocapsid assembly is still poorly understood. No detailed information is available on the nucleocapsid structure, and the regions of full-length NP involved in binding to viral RNA remain to be determined. In this report, novel findings are provided on critical interactions between the viral ribonucleoprotein components. We identify several amino acid residues in both the N-terminal and C-terminal domains of TCRV NP that differentially contribute to NP-NP and NP-RNA interactions and analyze their relevance for binding of NP to the L polymerase and for nucleocapsid activity. Our results provide insight into the contribution of NP self-interaction to RNP assembly and activity and reveal the involvement of the NP C-terminal domain in RNA binding.Fil: D'antuono, Alejandra Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Ciencias y Tecnología "dr. Cesar Milstein"; ArgentinaFil: Loureiro, Maria Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Ciencias y Tecnología "dr. Cesar Milstein"; ArgentinaFil: Foscaldi, Sabrina Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Ciencias y Tecnología "dr. Cesar Milstein"; ArgentinaFil: Marino, Cristina Ester. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Lopez, Nora Mabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Ciencias y Tecnología "dr. Cesar Milstein"; Argentin
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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