1,720,968 research outputs found
Entwicklung und Anwendung ribosomal gerichteter Hybridisierungssonden und Phylogenie aquatischer Pilze
No full textDas Ziel der Arbeit war die molekulare phylogenetische Charakterisierung aquatischer Pilze, die Evaluierung und Optimierung der Fluoreszenz in situ Methode (FISH) für filamentöse Pilze sowie die Entwicklung taxonspezifischer Oligonukleotidsonden für aquatische Pilze und deren Anwendung in dem Tieflandfluß Elbe und dem österreichischen Gebirgsbach Oberer Seebach. In der Elbe war innerhalb dreier Jahre mit elf verschiedenen Spezies nur eine geringe Diversität an aquatischen Pilzen nachweisbar. Die Mehrzahl der aus der Elbe isolierten Pilze waren den Bodenpilzen oder durch die Luft verbreiteten Arten zuzuordnen. Fixierte Schaumproben aus der Elbe wiesen mit durchschnittlich 3,75 Konidien pro 10 ml sehr niedrige Konidienzahlen auf, während in Schaumproben aus dem Oberen Seebach 5635 (Herbst) und 2654 Konidien (Sommer) pro 10 ml gefunden wurden. Während zwei dreiwöchigen Probenahmen am Oberen Seebach wurden 36 verschiedene Spezies aquatischer Pilze nachgewiesen. Die phylogenetische Analyse unterschiedlicher ribosomaler DNS-Regionen von elf Spezies bestätigt einen polyphyletischen Ursprung aquatischer Pilze. Auf der Basis von 18S rRNS-Sequenzdaten wurden neun Spezies (Tetracladium marchalianum, Lemonniera terrestris, L. aquatica, Varicosporium elodeae, Tricladium angulatum, T. splendens, Alatospora acuminata, Anguillospora crassa und A. furtiva) in die Klasse der Leotiomycetes eingeordnet. Zwei Spezies wurden in die Klasse der Sordariomycetes (Heliscus lugdunensis) bzw. der Dothideomycetes (Anguillospora longissima) eingeordnet. Die Analysen der ITS und LSU-Sequenzbereiche stellten T. marchalianum in die Nähe der Ordnung Helotiales. Auf der Basis von ITS-Sequenzdaten wurden die sensu stricto und sensu lato Morphotypen von A. acuminata separiert. Die Ergebnisse der ITS-Sequenzanalysen von T. splendens und A. crassa weisen auf eine enge Verwandtschaft beider Arten untereinander und zu dem marinen Pilz Zalerion varium (Helotiales) hin. T. angulatum wurde in ITS-Analysen den Helotiales zugeordnet und zeigt enge Beziehungen zur Familie Hyaloscyphaceae. Während A. crassa der Ordnung Helotiales näher steht, wurde A. longissima in die Ordnung Pleosporales eingeordnet. Hier zeigte A. longissima eine nähere Verwandtschaft zu Arten der Gattung Lophiostoma als zu Arten der vermuteten Teleomorph-Gattung Massarina. Folglich muß die Gattung Anguillospora auch aufgrund der Ergebnisse der Sequenzanalysen überarbeitet werden. Für die phylogenetischen Analysen und die Entwicklung taxonspezifischer Oligonukleotidsonden wurde das ARB Softwareprogramm an die Bearbeitung von pilzlichen Sequenzdaten angepaßt. Die bestehende Datenbank wurde um umfangreiche Datensätze von 18S, ITS und 28S rRNS- Pilzsequenzen erweitert. Die neu entwickelten Sonden FUN1429 und MY1574, spezifisch für einen breiten phylogenetischen Bereich der Eumycota, die gattungspezifische Sonde TCLAD1395 (Tetracladium) sowie die artspezifischen Sonden ALacumi1698 (A. acuminata), TRIang322 (T. angulatum), Alongi340 (A. longissima) und Hlug1698 (H. lugdunensis) sind gegen die 18S rRNS gerichtet. Die artspezifischen Sonden für T. marchalianum (TmarchB10, TmarchC1_1, TmarchC1_2) und A. longissima (AlongiB16) sind 28S rRNS gerichtet. Die Spezifität aller neu entwickelten Sonden konnte durch computergestützte Sequenzanalyse und in situ Hybridisierungen gegen Zielorganismen und Vertreter anderer phylogenetischer Gruppen bestätigt werden. Umfangreiche Testserien ergaben, daß die durch die Sonden vermittelten Fluoreszenzsignale sowohl qualitativ als auch quantitativ durch die Fixierungsmethode, das Myzelalter, unterschiedliche Stoffwechselaktivität verschiedener Strukturen im Myzel, Autofluoreszenzen, die Mikroskopiertechnik sowie die Permeabilität der Pilzzellwände wesentlich beeinflußt werden. Durch Markierung der Sonden mit roten Fluoreszenzfarbstoffen konnte die natürliche Autofluoreszenz der Pilze im Bereich des grünen Lichts umgangen werden. Mit steigendem Alter des Myzels erhöhte sich in der Regel auch die Intensität der Autofluoreszenz. Die Autofluoreszenz von Organismen und Substraten konnte durch Verwendung von Natriumborhydrid reduziert werden. Bei Verwendung von konfokaler Laser-Scanning-Mikroskopie wurden Fluoreszenz-Emissionen außerhalb der Fokusebene minimiert und die dreidimensionale Darstellung von Pilzen auf Blättern ermöglicht. Die Intensität der Sondensignale war positiv korreliert mit dem metabolischen Status unterschiedlicher Strukturen im Myzelkörper. Die Durchlässigkeit der Pilzzellwände für Oligonukleotidsonden konnte durch eine Behandlung mit Chitinase verbessert werden. Erheblich konnte die Intensität sowie die Reproduzierbarkeit der Sondensignale durch den Einsatz der neu entwickelten Electroporation-FISH Methode gesteigert werden. Durch Einsatz der Sonden MY1574 und Hlug1698 konnten stoffwechselaktive Pilze in der Elbe nachgewiesen werden. Ebenso wurden Pilze aus dem Oberen Seebach auf Blättern und Polyethylen-Objektträgern mit den neu entwickelten, pilzspezifischen Gensonden nachgewiesen.The aim of the study was the molecular phylogenetic characterisation of aquatic hyphomycetes, the evaluation of the factors influencing their accessibility for fluorescence in situ hybridisation and the application of newly developed taxon specific rRNA-targeted oligonucleotide probes in the German lowland river Elbe and the Austrian alpine 2nd order stream Oberer Seebach. During 24 sampling campaigns in three years performed in the Elbe river, with only eleven different species a remarkable low diversity of aquatic hyphomycetes could be distinguished while the majority of fungi observed were terrestrial and airborne fungi. Conidial numbers in fixed foam samples of 3.75 10 ml -1 (autumn) were extremely low in the Elbe river compared to conidial numbers of 5635 10 ml -1 (autumn) and 2654 10 ml -1 (summer) in foam samples from the Oberer Seebach. During two short term, three week campaigns 36 different species of aquatic hyphomycetes could be observed and isolated from different substrates in the Oberer Seebach. Phylogenetic analyses of sequences of different rDNA regions of 11 species of aquatic hyphomycetes confirmed the assumption of a polyphyletic origin of aquatic hyphomycetes. On the basis of 18S rDNA data, nine species (Tetracladium marchalianum, Lemonniera terrestris, L. aquatica, Varicosporium elodeae, Tricladium angulatum, T. splendens, Alatospora acuminata, Anguillospora crassa, and A. furtiva) were placed in the Ascomycota class Leotiomycetes. The species Heliscus lugdunensis and Anguillospora longissima were placed in the classes Sordariomycetes and Dothideomycetes, respectively. In ITS and LSU sequence analyses T. marchalianum showed most likely phylogenetic affinities to the Helotiales. On the basis of ITS sequence data, two morphotypes of A. acuminata were separated into two clades containing the sensu lato and the sensu stricto type, respectively. T. splendens showed close relationships to A. crassa and to the marine hyphomycete Zalerion varium (Helotiales) in ITS analyses. T. angulatum is related to the Helotiales and showed close relation to members of the family Hyaloscyphaceae as revealed from ITS analyses. A. crassa was placed most likely within the Helotiales. In contrast A. longissima is a member of the Pleosporales with closer relation to the genus Lophiostoma than to the suspected teleomorph genus Massarina. Thus the genus Anguillospora has to be revised. For the phylogenetic analyses and subsequent probe design, the ARB software environment for sequence data was adapted to properly work with fungi by incorporating 18S rRNA and 28S rRNA secondary structure information and extending and generating 18S rRNA, ITS and 28S rRNA sequence databases. Newly developed 18S rRNA-targeted taxon-specific probes termed FUN1429, MY1574 are specific for a wide range of Eumycota. The genus specific probe TCLAD1395 (Tetracladium) as well as the species specific probes ALacumi1698 (A. acuminata), TRIang322 (T. angulatum), Alongi340 (A. longissima) and Hlug1698 (H. lugdunensis) are targeted against the 18S rRNA. The probes TmarchB10, TmarchC1_1, TmarchC1_2 and AlongiB16, specific for T. marchalianum and A. longissima, respectively, are targeted on the 28S rRNA. The specificity of all newly designed probes was successfully tested in whole fungal hybridisations against target and non-target organisms. The fixation method, the fungal inherent and substrate mediated autofluorescence, the imaging technique, the age of the mycelium, the different mycelial parts, and the permeability of fungal cell walls were shown to be the most obvious influencing factors for the detection of fungal FISH signals. Autofluorescence scans revealed that many freshwater fungi showed inherent fluorescence in the green visible light spectrum. This could be successfully overcome by use of probe labels emitting red fluorescence. Generally, autofluorescence intensities increased with the age of the fungal mycelium. Bleaching of autofluorescing organisms and substrates with sodiumborohydrid was useful for enhanced probe signal detection. Employing epifluorescence microscopy, fungal FISH signals were often insufficient to detect due to high background noise. In contrast, confocal laser scanning microscopy significantly enhanced the detection of fungal FISH signals. Additionally, the spatial distribution of freshwater fungi on leaves could be documented more clearly by CLSM. The FISH signal intensity and rRNA content resembling the metabolical status of different structures of the mycelium were positively correlated. The cell wall permeability could be enhanced by chitinase treatment. However, the most reliable results for FISH signal detection were yielded by employing the Electroporation-FISH method newly developed in this study. Application of the probes MY1574 and Hlug1698 yielded FISH signals of metabolically active hyphae in the Elbe river. In the Oberer Seebach aquatic hyphomycetes were successfully detected on PE slides, leaves and in germination experiments using the set of newly developed fungal FISH probes
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
- …
