1,720,957 research outputs found
The role of homeodomain-leucine zipper class I transcription factors in the drought response of wheat.
Full text linkTraditional breeding for increased yield under water limiting conditions has been hampered by the complexity of the polygenic plant response and the unpredictability of seasonal conditions. This has made it difficult to observe the hereditability of a selected trait. Given these difficulties, breeders have been selecting for yield improvement under water deficit by phenotyping methods rather than by genetic association. Hence, an improvement in yield under water limited conditions is often seen under well-watered conditions and so selection has been for yield increase and not “drought tolerance”. Understanding the plant drought response at the molecular level will aid efforts to increase yield under water limited conditions. An approach to reveal the molecular mechanisms of the plant drought response is to study the role of transcription factors which act as global regulators of gene expression. Members of the homeodomain-leucine zipper class I (HD-Zip I) γ-clade TFs show drought and ABA inducible expression and are believed to act in plant adaptation to abiotic stress. It was therefore considered that, HD-Zip I γ-clade TFs pose good candidates for studying a part of the drought response mechanism. To this end three wheat γ-clade HD-Zip I TFs were isolated, TaHDZipI-3, TaHDZipI-4 and TaHDZipI-5, and studies of their function were performed. Studies were performed to confirm the relationship of the isolated γ-clade TFs with homologues. The three wheat γ-clade HD-Zip I TFs show patterns of induction by abiotic stresses and interaction with the putative HD-Zip I cis element that suggests differences exist between dicot and monocot homologues. Transgenic wheat and barley plants constitutively over-expressing wheat γ-clade HD-Zip I TFs have been produced. Investigations were made to analyse any role of HD Zip I TFs in stem development and the regulation of lignin deposition in anther development. Wheat constitutively over-expressing TaHDZipI-4 displayed no differences in stem length contrary to other reported observations made on γ-clade HD-Zip I TFs. However, a stem developmental series showed that there is an increase in endogenous expression correlating with internode maturity and a developmentally specific spike in expression in the entire stem. Analysis of lignin deposition was performed using barley expressing TaHDZipI-3, TaHDZipI-4, and ZmHDZip1 under the 35S promoter. Results suggest that no differences in anther lignin deposition have occurred. Transgenic wheat was grown under two different drought scenarios, sustained water deficit or cyclic drought, to assess the effect of γ-clade HD-Zip I TFs under the regulation of a strong drought inducible promoter. No improvement in yield under water deficit was observed. It appears that wheat HD-Zip I γ-clade TFs have diversified from known dicot homologues in their expression characters and role as transcription factors. Hence, the mechanisms of action of these TFs in monocots may be different from that in Arabidopsis. Despite the efforts and analyses presented here as part of the PhD project, the role of γ-clade HD-Zip I TFs in the plant drought response remains elusive.Thesis (Ph.D.) -- University of Adelaide, School of Agriculture, Food and Wine, 201
Analysis of the stress-inducible promoter of TdDHN8/WCOR410 from wheat using transient expression assays.
Full text linkThe master research project went through eight months from February 5th to September 27th, and has successfully been completed as we planned at the beginning. The research was mainly focusing on the analysis of a new wheat promoter, pTdDHN8/WCOR410, which was originally presumed as a drought-inducible promoter. As a backup research plan, we also tested nine lines of the T1 transgenic barley plants transformed with the pRab17-GUS fusion under 250mM salt stress.
We spent nearly five months to optimize the experimental conditions of transient expression assay using cell suspension cultures that are rarely used for the analysis of inducible promoter in plants. The effort included: 1) which plant tissue was optimum to characterize the activity and inducibility of the TdDHN8/WCOR410 promoter; 2) how to minimize the factors that affected the transformation efficiency in cell suspension cultures via particle bombardment; 3) how to precisely induce the osmotic stress in the growth medium. Finally, we efficiently optimized the experiment conditions, paving the way to further dissect the TdDHN8/WCOR410 promoter activity using transient expression assay in cell suspension cultures. In term of the backup research, we got four transgenic plants that were qualified using GUS staining assay, and they have been transplanted into soil for T2 seeds.
In the present thesis, the revised version of literature review, which has been examined by Dr. Andrew Jacobs, Dr. Oliver Cotsaftis, and Prof. John Randles on March, is present in the first part. The second part is the revised manuscript of the TdDHN8/WCOR410 promoter analysis according to the format of The Plant Journal. The final version of my master thesis was revised based on the critical suggestions by Prof. Peter Langridge, Dr. Oliver Cotsaftis, and Dr. Bujun Shi. Although some big progress was made in last few months, yet we recognize that more hard work is still needed to address the problem of the big variation of transformation efficiency in cell suspension cultures via particle bombardment, and extend our findings in the thesis in the next few months. At the end of my master study, I thank those lovely persons who help me for the master research in plant genomics center. The big gratitude are also given to our program coordinator Dr. Amanda Able for her assistance during my two-year master study in The University of Adelaide, and my supervisors Dr. Sergiy Lopato and Dr. Serik Eliby for their kindness and patience in my master research project.Thesis (M.Bio (PB)) - University of Adelaide, School of Agriculture, Food and Wine, 200
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
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