1,721,007 research outputs found
Characterization of the cytoplasmic chaperonin containing TCP-1 from the Antarctic fish Notothenia coriiceps.
No full textThe cytoplasmic chaperonin containing TCP-1 (CCT) plays a critically important role in the folding and biogenesis of many cytoskeletal proteins, including tubulin and actin. For marine ectotherms, the chronically cold Southern Ocean (-2 to +2 degrees C) poses energetic challenges to protein folding, both at the level of substrate proteins and with respect to the chaperonin/chaperone folding system. Here we report the partial functional and structural characterization of CCT from an Antarctic notothenioid fish, Notothenia coriiceps. We find that the mechanism of folding by the Antarctic. sh CCT differed from that of mammalian CCT: (1) the former complex was able to bind denatured beta-tubulin but (2) when reconstituted with rabbit Cofactor A, failed to release the protein to yield the tubulin/cofactor intermediate. Moreover, the amino acid sequences of the N. coriiceps CCT beta and theta chains contained residue substitutions in the equatorial, apical, and intermediate domains that would be expected to increase the flexibility of the subunits, thus facilitating function of the chaperonin in an energy poor environment. Our work contributes to the growing realization that protein function in cold-adapted organisms reflects a delicate balance between the necessity of structural flexibility for catalytic activity and the concomitant hazard of cold-induced denaturation
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
Different roles of two gamma-tubulin isotypes in the cytoskeleton of the Antarctic ciliate Euplotes focardii: remodelling of interaction surfaces may enhance microtubule nucleation at low temperature
No full textIn ciliates, different microtubular structures are nucleated from diverse Microtubule Organizing
Centers (MTOCs). c-Tubulin is a tubulin superfamily member that plays an essential role in
microtubule nucleation at the MTOCs. However, little is known about mechanisms regulating the
activity of c-tubulin on different MTOCs and during the cell cycle. In Tetrahymena thermophila, the
a- and b-tubulin expression is regulated mainly at the transcriptional level, and changes in the ratio of
polymerized/unpolymerized tubulin dimers lead to an increase or decrease of a- and b-tubulin
transcription. This study deals with the characterization of c-tubulin in the amicronuclear ciliate
Tetrahymena pyriformis. Sequence analysis revealed some specific substitutions in nucleotidebinding
loops characteristic of the Tetrahymena genus and putative conserved phosphorylation sites
located on the external surface of the c-tubulin molecule. c-Tubulin expression during the cell cycle, in
the presence of microtubular poisons and after deciliation, was also characterized. We found that
c-tubulin mRNA levels are correlated with basal body proliferation and c-tubulin nuclear localization.
We also found that c-tubulin expression changes during anti-microtubular drugs treatment, but does
not changes during reciliation. These findings suggest a relationship between the level of
unpolymerized tubulin dimers and c-tubulin transcription
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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