1,721,011 research outputs found
Intravarietal DNA polymorphisms in grapevine (Vitis vinifera L.)
No full textThe high genetic variability of grapevines enabled the clear distinction of varieties by using different molecular markers as RFLPs, RAPDs and STRs. These markers, however show some limits in the differentiation of clones belonging to the same variety of Vitis vinifera. In this study a different approach was considered, the AFLP (Amplification Fragment Length Polymorphism) method was used in order to find intravarietal genetic diversity and to develop a method for the identification of clones. About sixty primer pairs on nine different international grape cultivars such as Chardonnay, Cabernet Sauvignon, Merlot were chosen, and in each reaction an average of 9 fragments were polymorphic. A number of clones belonging to these varieties were typed using the more informative primer combinations. Finally, only clones belonging to the varieties Pinot blanc, Pinot noir and Pinot gris were analysed using about further fifty primer pairs in order to investigate their genetic diversity. Amplification products were analysed with different techniques: by loading on 4.5% acrylamide gel and isotope detection, by loading on 8% acrylamide gel and detection by LI-COR (MWG-Biotech), and by capillary electrophoresis on the ABI PRISM 310 (Perkin Elmer) automated fluorescent sequencer using GeneScan 3.1 analysis. Some of the polymorphisms detected among clones were not reproducible when using newly digested DNA samples. Nevertheless, other polymorphisms have been confirmed using the different electrophoresis systems, and will be considered in the development of SCARs. All the data were used to estimate the genetic distance among the grapevines. The possible application of AFLPs as molecular markers for clonal selection, identification, certification and protection was discussed
Genotype-dependent expression of specific members of potato protease inhibitor gene families in different tissues and in response to wounding and nematode infection
No full text: Protease inhibitors (PIs) are small ubiquitous proteins with a variety of biological functions in plants, including protein stabilization, modulation of apoptosis and defense against pathogens. Kunitz-like inhibitors (PKPIs) and proteinase inhibitors 1 (PI-1) are abundant in storage organs of potato plants and are up-regulated in other tissues in response to biotic and abiotic stress. However, little information is available on genotype-dependent regulation of individual PKPI group- and PI-1 genes. We isolated, sequenced and characterized four novel full-length PI-1 cDNAs (PPI3A2, PPI3A4, PPI2C4 and PPI2C1A) from Solanum tuberosum cv. Desirée. Specific primers were developed for PI-1 genes PPI3A2, PPI3B2 and PPI2C4 and the three PKPI homology groups A, B and C. Their expression profiles were studied by semi-quantitative RT-PCR in comparison with transcripts of the PI-1, Pin2 and PR1 gene families in various tissues, after wounding and Globodera rostochiensis infection of nematode-resistant genotypes P40 and LB7/4/c-I-7, and susceptible cv. Desirée. Individual PI-1 genes and PKPI homology groups were expressed in a tissue- and genotype-dependent manner after wounding and nematode infection. The differences in PI expression patterns were related to the intensity, type of inhibitors produced, and the kinetics of induction. Therefore, different genotype-environment combinations produce different sets of PI transcripts. Potato plants reacted to G. rostochiensis infection by modulating PKPI, PI-1 and Pin2, but not PR1 gene expression, suggesting that the jasmonic acid but not the salicylic acid defense signaling pathway is activated. PI expression profiles were not correlated with the resistance status of the potato genotype infected with G. rostochiensis
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
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