1,721,013 research outputs found
Identification and Exploitation of Petunia Transposable Elements: a brief history
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Transcript profiling on developing Petunia hybrida floral organs
No full textThe cDNA-AFLP transcript profiling technique was used to analyse gene expression during flower development in Petunia hybrida. Reproductive and vegetative floral organs were sampled at five developmental stages and gene expression profiles were compared. This allowed us to assemble an inventory of genes expressed mainly in anthers during microspore development and in ovaries during macrosporogenesis. About 6,000 transcript tags were generated, 354 of which showed a modulated and/or organ-specific expression pattern. Stamen-specific transcripts exhibiting an upregulation in gene expression were well represented in our screening. Ovary-specific transcripts were less frequently observed and often displayed a constant level of gene expression. Of 194 fragments characterised further by sequencing, 35% showed homology with known genes in a database search. They belong to a wide range of gene classes, such as proteases, transcription factors and genes involved in metabolism, cell cycle and disease resistance. The usefulness of cDNA-AFLP transcript profiling as a tool to unravel complex developmental processes at the molecular level is discussed
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
Benzenoids dominate the fragrance of Petunia flowers
No full textIn the last decade Petunia hybrida has emerged as the model of choice to study volatile benzenoid and phenylpropanoid synthesis, emission and regulation. These volatiles are synthesized predominantly in the corolla limb and emission is highly regulated, with a circadian rhythm, during corolla development, pollination and senescence. With all the biochemical and molecular tools available, much of our understanding of volatile benzenoids/phenylpropanoids has been obtained with Petunia, as illustrated in this chapter
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