1,721,071 research outputs found
Characterization of the blaKPC gene across three different bacterial genera
No full textInitially discovered in 1996, Klebsiella pneumoniae Carbapenemase (KPC) encodes for an enzyme which can hydrolyze the entire β-lactam drug class. Predominantly found in K. pneumoniae and to a lesser extent other species of Gram-negative bacteria, KPC is typically encoded on a Tn-3 like transposon found on plasmids which harbor additional resistance genes. Infections with KPC producing bacteria are associated with increased morbidity and mortality due to difficulties in detection of organisms that produce KPC in addition to having few effective therapeutic agents to treat such infections.|The impact KPC-producing pathogens have on the outcome of antibiotic therapy and the ability to detect the enzyme in susceptibility assays relies in part on the levels of protein product produced by the organism. Two promoters have been identified upstream of the KPC structural gene. However, upstream regions capable of binding potential transcription factors have not been identified. In addition, eight different deletion isotypes have been described involving deletions within the KPC promoter ranging from no deletion to a 256 bp deletion. Previous research has shown that a 99 bp and a 188 bp deletion in the promoter lead to an increase in gene expression but the effects on the level KPC protein production have yet to be evaluated. In this study, we characterize the RNA and protein production of KPC in both K. pneumoniae and E. coli isolates with and without deletions in the KPC promoter. Additionally, we evaluated the KPC promoter region for possible DNA binding proteins using electrophoretic mobility shift assays and whole cell lysates from three different genera, K. pneumoniae, E. coli, and Enterobacter cloacae. Sequence homology of the distal promoter to the σ70 sequence, suggest that the distal promoter was responsible for driving gene expression. Additionally, factors which regulate initiation of transcription must bind upstream of the distal promoter of the KPC gene. Therefore, we hypothesized that the distal promoter was the dominant promoter driving KPC RNA and protein production in clinical isolates of K. pneumoniae, E. coli and E. cloacae.|A series of eight clones with systematic deletions to the promoter region were utilized to determine which promoter was dominant. In addition, clinical isolates of K. pneumoniae and E. coli possessing the full-length or 99 base pair deletion in the promoter were evaluated and compared for RNA and protein production levels. The E. coli isolates were of various sequence types (ST) including ST131, ST964, ST2521, ST648, ST372, and ST404. Expression and protein analysis were measured by real-time reverse transcription PCR and western blot analysis. Carbapenem MICs were measured using Etest®, agar and microbroth dilutions. Gel-shift mobility assays were performed using whole cell lysates from K. pneumoniae, E. coli and E. cloacae and a 50 base pair (bp) fluorescently labeled probe with DNA sequence specific to a region located eight bp upstream of the distal promoter.|The deletion clones identified the distal promoter as the only promoter responsible for RNA and protein production resulting in carbapenem MICs at or above the resistant breakpoint. Interestingly, when E. coli ST131 isolates were evaluated for RNA and protein production, these isolates had an increase in RNA expression that did not correspond to increased levels of KPC protein production compared to non-ST131 isolates. Comparisons of clinical isolates with a deletion of 99 bps in the promoter vs. isolates with the full-length promoter showed the RNA and protein levels varied regardless of the presence of the 99 bp deletion. Very little correlation was observed among the isolates with respect to KPC protein production and carbapenem MICs. Although some isolates had increased protein production that correlated with increased carbapenem MICs, many isolates had elevated carbapenem MICs in the presence of very low levels of KPC protein production. These data suggest that additional resistance mechanisms contribute to the carbapenem MICs and would be of interest of further study. Finally, using whole cell lysates from three different genera, EMSA identified a single band in the presence of K. pneumoniae and E. cloacae protein lysates while the E. coli isolates resulted in two shifted bands.|Taken together, the data presented in this thesis work shows that the distal promoter of the KPC gene is required to drive expression resulting in protein production that in the deletion clones correlates with carbapenem MICs that reflect a resistant phenotype. Additionally, regions within the upstream sequence of the distal promoter interact with DNA binding proteins. However, in clinical isolates the correlation is not clear with no decisive impact with respect to deletions within the full-length promoter or sequence type of the E. coli expressing the gene.ProQuest Traditional Publishing Optio
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
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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