1,720,958 research outputs found
Role of Bovine Ileal Sub-epithelial Myofibroblasts and Epithelial Cells in Innate Immunity
Get PDFGastro-intestinal (GI) tract harbors largest number of microbiota as well as the largest number of immune cells for a given tissue. The host needs to mount an effective immune response against invading pathogens and tolerance against commensals. Thus, regulatory mechanism and barrier function of the GI tract are of utmost importance for appropriate host microbe interaction and gut homeostasis. Intestinal epithelial cells (IECs) act as the first line of defense against invading pathogens. IECs recognize pathogens and commensals and mount an effective innate immune response. Such recognition of pathogens is mediated through germ line encoded pattern recognition receptors (PRRs). Intestinal sub-epithelial myofibroblasts (ISEMFs) reside just beneath the surface epithelium and are involved in maturation and differentiation of epithelium. ISEMFs protect from pathogens that breach surface epithelium by expressing PRRs. Lack of stable intestinal epithelial and sub-epithelial myofibroblast cell lines has slowed down scientific studies on these cells. In this study, we established and characterized ISEMF cells from the ileum of a 2-day old calf. We also had generated stable bovine ileal epithelial cell (BIEC-c4) cultures in our lab. On real time-quantitative polymerase chain reaction (RT-qPCR) analysis both these cell types expressed Toll-like receptors (TLRs) 1-9. To investigate their responses to various pathogen-associated molecular patterns (PAMPs), we stimulated both cell types for 3 hours and 24 hours with various PAMPs. The RT-qPCR assay was used to investigate changes in TLR gene expression and in cytokine genes following stimulation. Lipopolysaccharide, peptidoglycan, and flagellin were used as bacterial ligands of surface PRRs. Similarly, γ-D-Glu-mDAP, muramyl dipeptide, polyinosonic:polycytidylic acid, poly I:C complexed with lyovec, and imiquimod were used as ligands of cytosolic and endosomal PRRs. Bovine ileal ISEMFs responded to bacterial PAMPs and to ligands of cytosolic and endosomal PRRs by significantly altering TLR gene expression. Unlike bovine ISEMFs, BIEC-c4 cells responded only to bacterial ligands. Thus, we conclude that bovine ileal ISEMF can be a good model to study innate immune responses and signaling pathways occurring at subepithelial compartment. However, BIEC-c4 cells may serve as a good in-vitro model to study enteric infectious disease pathogenesis and innate immune responses associated with them
RECEPTOR USAGE AND INFECTION BIOLOGY OF INFLUENZA D VIRUS
No full textInfluenza D virus (IDV) utilizes bovines as a primary reservoir with periodical spillover to other hosts. We have previously demonstrated by the traditional hemagglutination assay coupled with sialoglycan microarray and functional assays that IDV can recognize and bind both 9-O-acetylated N-acetylneuraminic acid (Neu5,9Ac2) and 9-O-acetylated N-glycolylneuraminic acid (Neu5Gc9Ac). Agricultural animals such as cattle can produce both Neu5,9Ac2 and Neu5Gc9Ac, while humans are genetically unable to synthesize Neu5Gc9Ac. The bifunctional enzyme, glucosamine (UDP-N-acetyl)-2-epimerase/N-acetylmannosamine kinase (GNE) is a master regulator of de-novo sialic acid synthesis while 9-O-Acetylation of sialic acids is catalyzed by CASD1 via a covalent acetyl-enzyme intermediate. To characterize in more detail, the role of human and non-human 9-O-acetylated sialic acids in IDV infection and determine which form of 9-O-acetylated sialic acids drives IDV entry and productive infection, we took advantage of cells either deficient in 9-O-acetylated sialic acid or completely devoid of sialic acid, and synthetic receptor analog-based feeding experiment in combination with the single-round and multi-round IDV infection assays. The data from our study indicated that IDV can utilize human Neu5,9Ac2 or non-human Neu5Gc9Ac as a functional receptor for infection. Ferret is a gold standard model for the study of human influenza viruses. Ferrets, like humans, can only synthesize Neu5,9Ac2 and lack Neu5Gc9Ac. We used ferrets to study the replication fitness and transmission of the influenza D virus and to evaluate its zoonotic potential. We demonstrated that IDV can utilize Neu5,9Ac2 for infection and transmission. Our studies provide compelling evidence that IDV has acquired the unique ability to infect and transmit in agricultural animals such as bovines that are relatively enriched in non-human Neu5Gc9Ac as well as in ferrets only expressing human Neu5,9Ac2. Results of this work provide the foundation for further investigation of infection biology and zoonosis of influenza D virus
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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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