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Kolonisierung mit Escherichia coli
No full textTo increase our understanding of bacterial intestinal colonization in animal populations lacking anthropogenic influence we devised the first objective and studied the diversity of E. coli in pristine wild animal population. Overall, E. coli in cormorants maintained a high diversity under minimal anthropogenic influences. E. coli were isolated from individual birds of two cormorant colonies located on small islands in lakes at least 100 km away from human settlements. Diversity of the isolates was studied using pulsed field gel electrophoresis (PFGE). 137 isolates of cormorant colony-1 and 75 isolates of cormorant colony-2 resulted in 60 and 33 PFGE types, respectively. Representative strains of each PFGE type were analysed in terms of phylogroups, extraintestinal virulence associated genes (exVAGs), adhesion to the chicken intestinal cell line and antimicrobials. Most isolates belonged to phylogroup B1 (68.3%) followed by B2 and E with B2 harbouring the highest total number of exVAGs per isolate. Surprisingly, a PFGE type with relatively few exVAGs displayed the highest isolation frequency, also showing a high adhesion rate. Comparative analysis of exVAGs to other E. coli populations of wildlife origin revealed that the secreted autotransporter toxin encoding sat gene was only present in cormorants.
The second objective was to characterize and identify factors contributing to the novel adhesion phenotype, known as Clumpy adhesion by the strain 4972 E. coli when incubated on human urinary bladder 5637 cell line. Transcriptome and proteome of adhered bacteria clustered together and diverged from bacteria in the supernatant. The clumpy structure was further explored in terms antibiotic stress where sessile structures could tolerate high antibiotic pressure of ampicillin up to 16 mg/ml and gentamicin up to 2 µg/ml. Data analysis unveiled differential expression of 623 genes between bacteria forming clumps and in supernatant. 148 genes were hypothetical and five hypothetical genes i.e., ffp, espX1, pilV, spnT and yggT along with four known genes i.e., dnaK, spy, flgH and fimH were targeted for deletion. Seven genes deletion mutants, three known (i.e., spy, flgH and fimH) and four hypothetical (ffp, pilV, spnT and yggT) genes were successfully generated and analysed for various parameters. ΔflgH showed loss of clumpy phenotype and adhesion ability up to 80% was regenerated by complementation. When antibiotic stress by ampicillin was applied after clump formation, Δffp depicted no effect of high concentration of ampicillin. In case of ΔpilV, adhesion significantly increased to 151% and upon complementation, adhesion was reduced to 53%. ΔspnT during ampicillin stressed adhesion fared almost 8.5 times better than the wild type strain. ΔyggT exhibited high adhesion of 145.5 % and upon reintroduction, adhesion decreased to 13%. Overall, we were able characterize a new phenotype and determined the role of genes contributing to clumpy adhesion phenotype.Um das Verständnis von der bakteriellen Darmbesiedlung in Tierpopulationen ohne anthropogene Einflüssne zu verbessern, wurde die Vielfalt von E. coli in unberührten Wildtierpopulationen untersucht. Die Diversität von E. coli in Kormoranen unter minimalen anthropogenen Einflüssen ist hoch. E. coli wurden von einzelnen Komoranen aus zwei Kolonien isoliert, die sich auf kleinen Inseln in Seen befinden (>100 km von menschlichen Siedlungen entfernt). Die Diversität der Isolate wurde mittels Pulsfeldgelelektrophorese (PFGE) untersucht. 137 Isolate von Kolonie-1 und 75 Isolate von Kolonie-2 ergaben 60 bzw. 33 PFGE-Typen. Repräsentative Stämme jedes PFGE-Typs wurden hinsichtlich Phylogruppen, extraintestinale Virulenz-assoziierte Gene (exVAGs), Adhäsion an einer Hühnerdarmzelllinie und Antibiotikaresistenzen analysiert. Die meisten Isolate gehörten zur Phylogruppe B1 (68,3 %), gefolgt von B2 und E, wobei B2 die höchste Gesamtzahl an exVAGs pro Isolat aufwies. Überraschenderweise wies ein PFGE-Typ mit relativ wenigen exVAGs die höchste Isolationshäufigkeit auf und zeigte eine hohe Adhäsionsrate. Eine vergleichende Analyse der exVAGs mit anderen E. coli - Populationen aus Wildtieren ergab, dass das sat-Gen (sekretierte Autotransporter-Toxin) nur bei Kormoranen vorkommt.
Das 2. Ziel war die Charakterisierung und Identifizierung von Faktoren, die zu einem neuartigen Adhäsionsphänotyp beitragen; wird E. coli-Stamm 4972 auf der Zelllinie 5637 inkubiert, adhäriert dieser in Klumpen. Transkriptom und Proteom der anhaftenden Bakterien gruppierten sich zusammen und unterschieden sich von den Bakterien im Überstand. Die klumpige Struktur wurde auf Antibiotikastress untersucht, wobei die sessilen Strukturen einen hohen Antibiotikadruck tolerierten (bis zu 16 mg/ml Ampicillin und bis zu 2 µg/ml Gentamicin). Die Datenanalyse ergab eine unterschiedliche Expression von 623 Genen zwischen Bakterien, die Klumpen bilden, und solchen im Überstand. 148 Gene waren hypothetisch. Fünf hypothetische Gene (ffp, espX1, pilV, spnT, yggT) sowie vier bekannte Gene (dnaK, spy, flgH, fimH) wurden gezielt deletiert. Sieben Gen-Deletionsmutanten (spy, flgH, fimH und ffp, pilV, spnT, yggT) wurden erfolgreich erzeugt und auf verschiedene Parameter untersucht. ΔflgH zeigte einen Verlust des klumpigen Phänotyps und die Adhäsionsfähigkeit wurde durch Komplementierung zu 80 % wiederhergestellt. Wurde nach der Klumpenbildung eine antibiotische Belastung mit Ampicillin durchgeführt, zeigte Δffp keine Wirkung bei hohen Konzentration. Bei ΔpilV erhöhte sich die Adhäsion signifikant auf 151 %, und nach der Komplementierung betrug die Adhäsion 53 %. ΔspnT schnitt bei Ampicillin-belasteter Adhäsion fast 8,5 Mal besser ab als der Wildtyp-Stamm. ΔyggT wies eine hohe Adhäsion von 145,5 % auf, und sank nach Wiedereinführung auf 13 %. Insgesamt konnten wir einen neuen Phänotyp charakterisieren und die Rolle von Genen bestimmen, die zum Phänotyp der klumpigen Adhäsion beitragen
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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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