1,720,958 research outputs found
Small heat shock proteins characterization in a probiotic model.
No full textSmall heat shock proteins (sHSP) are ubiquitous, low molecular weight proteins with chaperon-like activity. sHSP protect cell under stress conditions, critically contributing to survival to heat shock. Lactobacillus plantarum (Lp), a member of the lactic acid bacteria (LAB), is a probiotic species with biomedical and biotechnological applications. Unlike most lactobacilli, which have single shsp genes, three sHSP-encoding genes were identified in Lp WCFS1. Such redundancy might endow Lp with the capacity to cope with a broad range of stresses, thus accounting for its extraordinary environmental adaptability.
To unravel the role of Lp sHSP, knock out (KO) mutants for hsp1 and hsp3 were generated and phenotypically characterized. Growth and survival rates under diverse stress conditions, which are typical for probiotics, revealed a different contribute of the two sHSP to thermotolerance induction and cryprotection. However, neither hsp seemed essential to tackle such challenges. Accordingly, cellular protein aggregation in both mutants was not significantly different from the wild type. Comparative transcriptional patterns revealed that in the mutant genetic backgrounds there is an up-regulated basal expression of the un-mutated mate hsp and other stress-related genes genes, which may compensate for the loss of sHSP function, hence underlying the lack of a marked susceptibility to stress. hsp KO affected biofilm adhesive capacity, changed cell surface physicochemical properties, and drastically modified membrane fluidity upon stress.
These findings indicate that hsp1 and hsp3 have pleiotropic effects, fulfill overlapping activities in stress tolerance and housekeeping functions, and regulate membrane fluidity by a plausible direct association
Effect of abiotic stress conditions on expression of the Lactobacillus brevis IOEB 9809 tyrosine decarboxylase and agmatine deiminase genes.
Full text linkLactobacillus brevis IOEB 9809, isolated from red wine, is able to produce both tyramine and putrescine. Using a real-time quantitative reverse transription PCR (qRT-PCR) we analyzed the relative expression of L. brevis IOEB 9809 tdc and aguA1 genes, encoding, respectively, a tyrosine decarboxylase and an agmatine deiminase enzyme. Relative gene expression was monitored either during the different growth phases under optimal conditions or under abiotic stress commonly found in wine. The tdc and aguA1 specific cDNA were amplified with specific primers. Our results indicate that tdc and aguA1 genes are differently expressed during the different growth phases and transiently induced by ethanol (12% v/v) and acidic stresses (pH 3.2 and 5.0)
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
- …
