1,721,274 research outputs found
Functional characterization of the newly identified HCMV envelope glycoprotein UL116
Full text linkHuman Cytomegalovirus (HCMV) è un b-herpesvirus, la cui infezione può causare gravi patologie negli adulti immunocompromessi e nei feti infetti in utero. I complessi gH/gL/gO e gH/gL/UL128/UL130/UL131 (Pentamero) svolgono un ruolo chiave nell’ingresso e nel tropismo cellulare del HCMV. La variabilità della quantità relativa dei due complessi sulla superficie del virione si riflette nel diverso tropismo cellulare, e sembra essere regolata dall’interazione della proteina virale UL148 con gH favorendo la formazione del complesso gH/gL/gO. Recentemente è stato dimostrato che il gene UL116 codifica una proteina, precedentemente sconosciuta, che forma un eterocomplesso con gH sulla superficie di HCMV in maniera gLindipendente, e dalla funzione ignota. In un esperimento preliminare, il complesso ricombinante gH/UL116 è stato purificato ed utilizzato come sonda su un microarray rappresentante un chip di proteine umane alla ricerca di interattori, portando all’identificazione dei putativi recettori cellulari TREM-1, IL-6R e TARM-1. In questo lavoro abbiamo verificato che non vi sono interazioni tra il complesso ricombinante gH/UL116 ed i suoi putativi recettori cellulari TREM-1, IL-6R e TARM-1 su cellule trasfettate e neanche sulla superficie di diverse linee cellulari utilizzate in saggi di binding. Inoltre, sembra che in assenza della proteina gL, essenziale per la formazione dei complessi gH/gL/gO e Pentamerico, il complesso gH/UL116 non sia sufficiente per la rigenerazione e propagazione del virus. Tuttavia, qui mostriamo che l’assenza della proteina UL116 compromette l’infezione e la diffusione del virus in cellule epiteliali, oltre a ridurre l’incorporazione dei complessi gH/gLbased nel virione. Inoltre, proviamo che UL116 interagisce direttamente con UL148, suggerendo un coinvolgimento di UL116 nel corretto assemblaggio dei complessi gH/gL-based. Infine, sebbene sia ancora da verificare, l’assenza di UL116 sembra compromettere la presenza della proteina virale pp71 nei virioni, il che potrebbe influenzare una corretta replicazione di HCMV.Human Cytomegalovirus (HCMV) is a b-herpesvirus, whose infection can cause serious diseases in immunocompromised adults and in utero infected fetuses. The gH/gL/gO and gH/gL/UL128/UL130/UL131 (Pentamer) complexes play a key role in HCMV entry and cell tropism. The variability of the relative amount of the two complexes on the virion surface is reflected in different cell tropism and it appears to be regulated by UL148 viral protein interaction with gH favoring the formation of the gH/gL/gO complex. Recently it has been shown that the UL116 gene encodes a previously unknown protein that forms a heterocomplex with gH on the surface of HCMV in a gLindependent manner and by unknown function. In a preliminary experiment, the recombinant gH/UL116 complex was purified and used as a probe on a microarray representing a human protein chip searching interactors and leading to the identification of the putative cellular receptors TREM-1, IL-6R and TARM-1. In this work we verified that there are no interactions between the recombinant gH/UL116 complex and its putative cellular receptors TREM-1, IL-6R and TARM-1 on transfected cells and not even on the surface of different cell lines used in binding assays. Furthermore, it seems that in the absence of gL protein, therefore without formation of gH/gL/gO complexes and Pentamer, gH/UL116 complex is not sufficient for virus regeneration and
propagation. However, here, we show that the absence of UL116 protein compromises virus infection and spreading in epithelial cells as well as it causes the incorporation reduction of gH/gL-based complexes into the virion. Furthermore, we prove that UL116
interacts directly with UL148, suggesting an involvement of UL116 in the correct assembly of gH/gL-based complexes. Finally, although it is yet to be verified, the absence of UL116 seems to compromise the presence of pp71 viral protein in virions, which could influence a correct HCMV replication
Functional and structural characterization of HCMV complexes by dissecting molecular interactions
Full text linkHuman cytomegalovirus (HCMV) is a virus infecting the majority of adults worldwide. In healthy individuals, a strong immune response to HCMV is able to limit and contain the spread of the disease [1]. HCMV can infect a remarkably broad cell range within its host. The broad cell tropism of HCMV may reflect the abundance of distinct glycoprotein complexes in the virion envelope [10]. The core machinery for Herpesvirus entry comprises three highly conserved viral glycoproteins, glycoprotein B (gB), glycoprotein H (gH), and glycoprotein L (gL) [21].
In addition to gB and gH/gL, most Herpesviruses encode additional glycoproteins that are able to interact with gH/gL. For HCMV, this addition consist of the glycoprotein gO, to form gH/gL/gO complex, or the trimer UL128/UL130/UL131A (referred as “ULs”), to form a pentameric structure often designated as “Pentamer”. Viral entry into fibroblast or epithelial/endothelial and lymphoid cells relies on the presence of gH/gL/gO or Pentamer respectively [35, 40].
In an in vitro system, specific cysteines have been identified to stabilize these complexes and impairment of disulfide bonds formation abolishes complexes maturation and cellular trafficking [41]. Here we addressed the relevance of these disulfide bonds in the formation of HCMV entry complexes and on the infectivity of point mutated viruses. To this purpose, four recombinant Cys-mutated viruses, generated through mutagenesis of a Bacterial Artificial Chromosome (BAC) containing the entire genome of HCMV TR strain, were analysed for viral tropism on three different cell types. We also checked by Western blot the content of the pentameric proteins expressed by these mutants both in the extracts of infected fibroblasts and monocytic cells (HFF and THP-1, respectively) and in virions produced by infection of human fibroblasts. Surprisingly, results from our analysis showed that mutation on two specific cysteines involving gL disulfide bonds to gO or UL128 and to gH resulted in the loss of intracellular gL or expression level under the detection power of Wb. Two other Cys mutated viruses showed no differences in the levels of viral structural proteins compared to wt. These results suggest that the impairment of the disulfide bond involving binding of gL to UL128 or gO and gL to gH, cause instability of the gL protein with loss or reduced ability to form higher order complexes and likely cellular degradation.
However, our results show that infectious viruses can achieve a complete life cycle in absence of a crucial protein like as gL but it also raise the question of which pattern of factors, likely interacting with gH, are necessary as “surrogate” gL
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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