1,720,978 research outputs found
Reprogramación del polen y obtención de plantas doble-haploide de Capsisum annuum L.: Marcadores celulares y expresión de moléculas señalizadoras de estrés.
No full textUniversidad: Complutense De Madrid
Departamento: Genetica
Fecha De Lectura: 11/04/2008
Dirección:
Director: Maria Del Carmen Risueño Almeida
Codirector: Pilar Sanchez Testillano
Tribunal:
Presidente: Benjamín Fernández Ruiz
Secretario: Cristina Pardo Martín
Vocal: María Ángeles Bueno Pérez
Vocal: Óscar Visente Meana
Vocal: José María Seguí SimarroEl polen es capaz de cambiar su proceso de desarrollo, reprogramarse y entrar en una nueva ruta denominada embriogénica, tras un tratamiento de estrés. Tras su reprogramación, la microspora comienza a dividirse simétricamente dando lugar a proembriones y embriones que posteriormente continúan su desarrollo Regenerando plantas haploides o doble-haploides. En este contexto, el cultivo de anteras es, hoy en día, uno de los métodos más eficientes para la obtención de plantas doble-haploides, de gran utilidad para generar nuevas líneas isogénicas y variedades, así como para Estudios genéticos y de mutagénesis.
El pimiento (capsicum annuum l.) Es uno de los cultivos hortícolas más importantes desde el punto de vista Económico en españa, siendo éste el país con mayor producción de la unión europea.
En esta tesis doctoral, un primer objetivo ha sido la obtención plantas doble-haploides a partir de cultivos de Anteras de capsicum annuum yolo Wonder var. B. Hemos optimizado los protocolos existentes (Mitykó et al.,1995), estudiando diversos factores tales como la correlación entre la morfología de los botones florales, el tamaño y la coloración de las anteras con antocianina y el estadio de desarrollo de las microsporas, así como diversos aspectos del cultivo in vitro y el tratamiento de estrñes inductor de la embriogénesis. Por otro lado, se ha llevado a cabo la caracterización celular de las primeras etapas de desarrollo hasta el estado de torpedo en la embriogénesis de microsporas de Capsicum annuum L. Se ha determinado el nivel de ploidía de las plantas
procedentes del cultivo de microsporas, mediante citometría de flujo.
Un segundop objetivo ha sido el análisis de distintos aspectos del proceso de reprogramación del polen a embriogénesis, concretamente la identificación de marcadores en etapas clave y la expresión de proteínas de estrés y señalizadoras.Un segundo objetivo ha sido el análisis de distintos aspectos del proceso de reprogramación del polen a embriogénesis, concretamente la identificación de marcadores en etapas clave y la expresión de proteínas de estrés y señalizadoras.
Existe una estrecha relación entre las proteínas de choque térmico (HSPs) y el abandono de la ruta gametofítica hacia la embriogénesis. Hemos estudiado los cambios en la expresión y en la localización subcelular de dos proteínas de choque térmico, HSP70 y HSP90, en la ruta gametofítica y en varias etapas de la ruta embriogénica. Tras el tratamiento inductor se observó un gran aumento de la expresión de HSP70, y una traslocación al nucleolo de la misma; sugiriendo una función específicamente protectora de la maquinaria nuclear y reguladora de la expresión génica.
Se ha realizado una caracterización celular y ultraestructural (gametofítico y embriogénico) secuencial de todas las etapas de los procesos de desarrollo, mediante el empleo de técnicas histoquímicas e inmunocitoquímicas específicas, para elegir las fases fundamentales de estudio donde aparecen las características celulares y funcionales diferentes. Ha sido objeto de especial atención la definición de marcadores celulares que caracterizan y diferencian los do programas de desarrollo del polen, el gametofítico y el embriogénico, y que
indican los principales cambios de actividad metabólica que están asociados a la reprogramación del polen.Entre estos marcadores se han identificado los cambios en el tamaño y forma celular y nuclear, el patrón de condensación cromatínica, la organización funcional de la región intercromatínica y la arquitectura nucleolar, la población ribosómica y la densidad citoplásmica, la presencia y tamaño de gránulos de almidón y por último, la estructura y composición de las paredes celulares.
Se ha analizado la expresión in situ de moléculas señalizadoras como las ERKs, P-MAPKs y LOX, encontrándose diferencias en su expresión y localización subcelular entre las microsporas que se reprograman hacia proliferación (ruta embriogénica) frente a las que siguen su proceso normal de diferenciación (ruta
gametofítica). Asimismo se han detectado cambios en la composición de las paredes celulares en relación a los procesos de proliferación y diferenciación.
Muchos de los anticuerpos empleados han resultado ser buenos marcadores que nos permiten identificar de forma temprana en el cultivo las microsporas que se reprograman e inician la proliferación (ruta embriogénica): mayor proporción de ERK y MAPK en núcleo, aumento de cuerpos de Cajal nucleares, expresi¿¿on de PCNA asociado a replicación y mayor proporción de pectinas esterificadas (marcadas por JIM7) en las paredes celulares; frente a las que siguen su proceso normal de diferenciación (ruta gametofítica): acumulación de almidón, mayor proporción de ERK y PMAPK en citoplasma, y de pectinas no esterificadas (marcadas por JIM5), xiloglucanos (XG) y ramnogalacturonano II (RGII) en las paredes celulares.
Los resultados obtenidos aportan nueva información muy valiosa sobre los mecanismos que controlan el proceso de reprogramación del polen a embriogénesis en Capsicum annuum L, una especie de gran interés económico; información que puede ayudar a su explotación de forma más eficiente y a dirigir futuras estrategias en la mejora de este cultivo.Peer reviewe
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
- …
