1,720,963 research outputs found
Novel interactions of transglutaminase-2 with heparan sulphate proteoglycans: reflection on physiological implications
Full text linkThis mini-review brings together information from publications and recent conference proceedings that have shed light on the biological interaction between transglutaminase-2 and heparan sulphate proteoglycans. We subsequently draw hypothesis of possible implications in the wound healing process. There is a substantial overlap in the action of transglutaminase-2 and the heparan sulphate proteoglycan syndecan-4 in normal and abnormal wound repair. Our latest findings have identified syndecan-4 as a possible binding and signalling partner of fibronectinbound TG2 and support the idea that transglutaminase-2 and syndecan-4 acts in synergy
Inhibition of pollen tube growth is controlled by the inhibition of a novel extracellular transglutaminase activity: is transglutaminase involved in the subsequent pollen self-incompatibility PCD events?
No full textPlant sexual reproduction involves the interaction between male and female gametophytes, which still remains an enigma, and requires the Ca2+-dependent growth of pollen tube (male gametophyte).
We report the detection of the first extracellular plant TGase and demonstration that its extracellular protein crosslinking activity is essential for pollen germination. Transglutaminases (TGase or TG) are Ca2+-dependent widespread enzymes able to post-translationally modify proteins by forming bridges between protein-bound glutaminyl residues and -lysines or polyamines (1). TGases are also involved in apoptosis: for instance, crosslinking by TG2 facilitates the phagocytic clearance of dead cells (1). The research on plant TGases lags much more behind that in mammalian cells, however TGase is also involved in flower PCD (2).
In our model, extracellular inhibition of transamidating activity either by a monoclonal anti-TGase antibody or irreversible site directed inhibitors blocked pollen tube growth. TGase, immunolocalised on the pollen tube surface, was also capable of crosslinking labelled amines and the H6-Xpr-GFP substrate into extracellular proteins in immediate contact with the pollen tube. Contribution of TGase-mediated crosslinking in the pollen tube wall formation was confirmed also by the immunodetection of (-glutamyl)lysine crosslinks. These findings suggest that the enzyme functions in the attachment of the pollen tube to the female style and in the stabilisation of the pollen tube wall. Plant cell wall has been described as a cellular compartment important in cell communication. A well-documented case of this sort is the rejection of self-pollen in the self-incompatiblility (SI) reaction. SI-specific events involved in a PCD signalling pathway are subsequent to inhibition of pollen tube growth. As the extracellular matrix (ECM) is a key regulator of gametophyte communication, ongoing work is focusing on the putative involvement of the extracellular pollen TGase in the SI events that follows the inhibition of incompatible pollen tube growth.
1. Lorand L and Graham R M. (2003). Transglutaminases: crosslinking enzymes with pleiotropic functions. Nature Reviews Molecular Cell Biology Vol. 4, February 2003.
2. Serafini-Fracassini D, Del Duca S, Monti F, Poli F, Sacchetti G, Bregoli AM, Biondi S, Della Mea M. (2002). Transglutaminase activity during senescence and programmed cell death in the corolla of tobacco (Nicotiana tabacum) flowers.Cell Death Differ.: 9(3):309-21
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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