1,721,005 research outputs found
Host Cell-dependent Modulatory Role of Ras Homolog Enriched in Brain-Like-1 (RhebL1) Protein in Influenza A/NWS/33 Virus-infected Mammalian Cells
No full textBackground: The Mammalian Target of Rapamycin (mTOR) signaling pathway regulates protein phosphorylation and exerts control over major cellular processes. mTOR is activated by the small G-protein Ras Homolog Enriched in Brain (Rheb), which is encoded by the Rheb1 and Rheb-like-1 (RhebL1) genes. There is currently a paucity of information on the role of RhebL1, and specifically its involvement in viral infection. In the present study we investigated the role of RhebL1 during human influenza A/NWS/33 (NWS/33) (H1N1) virus infection of rhesus monkey-kidney (LLC-MK2) cells and human type II alveolar epithelial (A549) cells. Methods: To assess the efficiency of NWS/33 virus replication, the expression of viral nucleoprotein was examined by indirect immunofluorescence (IIF) and the viral yield by fifty percent tissue culture infectious dose assay. An RNA-mediated RNA interference approach was used to investigate the role of RhebL1 during NWS/33 infection. RhebL1 expression was evaluated by IIF, Western blotting, and enzyme-linked immunosorbent assays. A two-tailed Student’s t-test was applied to evaluate differences between groups. Results: RhebL1 was differentially expressed in the cell models used in this study. Silencing of the RhebL1 gene led to increased NWS/33 virus infection in A549 cells, but not in LLC-MK2 cells. Moreover, the expression of hyperphosphorylated cytokeratin 8, a marker of NWS/33 virus infection efficiency, increased in A549 cells depleted of RhebL1 but remained almost unchanged in LLC-MK2 cells. Conclusions: These are the first results showing involvement of the endogenous RhebL1 protein during viral infection. Our data suggests that RhebL1 exerts a host cell-dependent modulatory role during influenza virus infection. RhebL1 appears to be a restrictive factor against NWS/33 virus replication in A549 cells, but not in LLC-MK2
Avian Influenza A Viruses Modulate the Cellular Cytoskeleton during Infection of Mammalian Hosts
No full textInfluenza is one of the most prevalent causes of death worldwide. Influenza A viruses (IAVs) naturally infect various avian and mammalian hosts, causing seasonal epidemics and periodic pandemics with high morbidity and mortality. The recent SARS-CoV-2 pandemic showed how an animal virus strain could unpredictably acquire the ability to infect humans with high infection transmissibility. Importantly, highly pathogenic avian influenza A viruses (AIVs) may cause human infections with exceptionally high mortality. Because these latter infections pose a pandemic potential, analyzing the ecology and evolution features of host expansion helps to identify new broad-range therapeutic strategies. Although IAVs are the prototypic example of molecular strategies that capitalize on their coding potential, the outcome of infection depends strictly on the complex interactions between viral and host cell factors. Most of the studies have focused on the influenza virus, while the contribution of host factors remains largely unknown. Therefore, a comprehensive understanding of mammals' host response to AIV infection is crucial. This review sheds light on the involvement of the cellular cytoskeleton during the highly pathogenic AIV infection of mammalian hosts, allowing a better understanding of its modulatory role, which may be relevant to therapeutic interventions for fatal disease prevention and pandemic management
Highly Dynamic Cytoskeletal Networks Support Productive Viral Infection and Host Innate Immune Response Activation
No full textPurpose of ReviewIncreasing evidence shows that the onset of the host cytoskeleton changes during the viral infection process. The attainment of in-depth knowledge about the molecular pathways coopted by viruses to induce cytoskeleton remodeling represents a useful premise for designing broad-spectrum antivirals.Recent FindingsCurrent investigations suggest that viruses coopt specific host factors to induce cell type-related cytoskeleton modifications for successful cell invasion and viral progeny spread to neighboring cells. On the other hand, it has been argued that cytoskeletal dynamics represent the first line of innate antiviral response activation.SummaryHere, we highlight the role of the main cytoskeletal regulatory mechanisms responsible for modulating the structure/function of specific cytoskeletal proteins at the global and local levels, which may affect the outcome of virus infection
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
Epidemiological and molecular features of norovirus infections in Italian children affected with acute gastroenteritis.
No full textDuring a 5-year (2007-2011) surveillance period a total of 435 (15·34%) of 2834 stool specimens from children aged <14 years with acute gastroenteritis tested positive for norovirus and 217 strains were characterized upon partial sequence analysis of the polymerase gene as either genogroup (G)I or GII. Of the noroviruses, 99·2% were GII with the GII.P4 genotype being predominant (80%). GII.P4 variants (Yerseke 2006a, Den Haag 2006b, Apeldoorn 2008, New Orleans 2009) emerged sequentially during the study period. Sequence analysis of the capsid gene of 57 noroviruses revealed that 7·8% were recombinant (ORF1/ORF2) viruses including GII.P7_GII.6, GII.P16_GII.3, GII.P16_GII.13, GII.Pe_GII.2, and GII.Pe_GII.4, never identified before in Italy. GII.P1_GII.1, GII.P2_GII.1, GII.P3_GII.3 and GII.P6_GII.6 strains were also detected. Starting in 2011 a novel GII.4 norovirus with 3-4% nucleotide difference in the polymerase and capsid genes from variant GII.4 New Orleans 2009 was monitored in the local population. Since the epidemiology of norovirus changes rapidly, continuous surveillance is necessary to promptly identify the onset of novel types/variants
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
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