1,720,978 research outputs found
Characterization of an endoxylanase produced by an isolated strain of Bacillus sp
No full textMicroorganisms producing xylanase were screened for the enzymatic production of xylo-oligosaccharides from xylan. One of the bacteria isolated fi om compost produced an endoxylanase extracellularly. The bacterium was identified as Bacillus sp. according to its taxonomic characteristics examined. Xylanase production reached upto 5 U/ml after 22 h of culture in LB medium at 30 degrees C. The xylanase was purified by ammonium sulfate precipitation and gel filtration. The molecular weight of the xylanase was estimated to be 20,400 by SDS-PAGE. Optimal temperature and pH for the xylanase activity was 60 degrees C and 6.5, respectively. The enzyme was stable at temperatures upto 40 degrees C and pH values from 4 to 10. The xylanase was completely inhibited by the addition of 2 mM mercury ion. Apparent K-m and V-max values for oat spelt xylan were 9.2 mg/ml and 1954 U/mg protein, respectively. For birchwood xylan, the values were 6.3 mg/ml and 1009 U/mg protein, The predominant products of the xylan hydrolysis were xylobiose, xylotriose and xylotetraose, indicating that the enzyme is an endoxylanase. Upto 85% of the initially added enzyme (2 U/ml) was bound to 50 mg/ml of the insoluble fraction of oat spelt xylan after incubation at 30 degrees C for 30 min
Antifungal mechanism of a cysteine-rich antimicrobial peptide, Ib-AMP1, from Impatiens balsamina against Candida albicans
No full textThe antifungal mechanism of a 20-mer peptide, Ib-AMP1, derived from Impatiens balsamina was investigated. The oxidized (disulfide bridged) Ib-AMP1 showed a 4-fold increase in antifungal activity against Aspergillus flavus and Candida albicans than reduced (non-disulfide bridged) Ib-AMP1. Ib-AMP1 had very low activity for phospholipid disruption when compared with cecropin A(1-8)-magainin 2(1-12), a alpha-helical amphiphatic, antimicrobial peptide. Confocal microscopy showed that Ib-AMP1 binds on cell surface or penetrates into cell membranes. These results suggested that Ib-AMP1 may manifest its antifungal activity against Candida albicans by inhibiting a distinct cellular process rather than ion channel or pore formation in cell membrane
Cloning of novel trinucleotide-repeat (CAG) containing genes in mouse brain
No full textCAG trinucleotide repeat (CTR) sequence often appears in mammalian genome including transcription-regulatory protein and homeobox genes. Its expansion is associated with six genetic disorders in human. To identify novel CTR-containing genes expressed in mouse brain, a brain cDNA library was screened using an oligonucleotide, (CTG)(10). Eight clones were novel mouse genes and they were sequenced on both strands. The size of the cloned DNA ranged from 0.5 to 2.1 kb. The number of the CAG repeats in the clones ranged from 6 to 25. The inserts of the clones were analyzed for open reading frames and the peptide sequences were used for a GenBank homology search. Of the clones, one (CAG-6) shared 13 consecutive identical amino acid residues with the OB-cadherin gene, a member of cadherin family. CAG-14 showed high homology (657 nucleotides identity in 1022 nucleotides; 64%) with the 3'-untranslated region of rat leukocyte common antigen-related (LAR) tyrosine phosphatase receptor. All the 8 clones were originated from mouse DNA as judged by Southern blot analysis of mouse genomic DNA. The expression of the clones in mouse brain was addressed by RT-PCR and 4 clones showed specific expression. (C) 1997 Academic Press
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
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