1,720,954 research outputs found
Role of miRNAs in carbon metabolism and stress responses in Arabidopsis thaliana mitochondrial uncoupling protein mutants ucp1/2/3 and activation-tagged transcription factor allele PRODUCTION OF ANTHOCYANIN PIGMENT/PAP1-D/MYB75
No full textPlant sugars, specifically the transported disaccharide primary product of photosynthesis sucrose, control multiple aspects of the plant life cycle including structure, growth, and development. Notably, sucrose functions as a signaling molecule by unknown molecular mechanisms to facilitate various stress adaptations. Accumulation of high sugar concentrations in plants is a hallmark associated with many environmental stimuli, abiotic, and biotic stresses, resulting in accumulation of antioxidant secondary carbon metabolites anthocyanins and flavanoids. From a regulatory perspective, some microRNAs (miRNAs) are potentially components of sucrose signaling pathways because of their established roles in secondary carbon metabolism. However, current understanding of the role of miRNAs in sucrose signaling pathway is very scarce. In this study, I endeavored to uncover the effect of exogenous high sucrose stress on miRNA profiles in Arabidopsis mitochondrial uncoupling protein mutants (ucp) that are defective in reactive oxygen species (ROS) homeostasis and pap1-D, a positive effector transgene mutant of secondary metabolite anthocyanin pathway. My aim is to better understand the UCP protein roles in response to oxidative stress and subject to regulatory control by sugar signaling, and to ascertain the importance of miRNAs impacting primary metabolism and regulation of carbon partitioning to the secondary metabolite pathways antioxidant anthocyanins and flavanols. Qualitative measurements of ROS hydrogen peroxide and superoxide abundance with specific chromogenic stains showed higher endogenous ROS in sucrose-treated samples. My analysis of small RNA deep sequencing datasets from sucrose-treated mutant and wild-type seedlings shows that high exogenous sucrose treatment altered the expression of many miRNAs inferred to be involved in primary metabolism, stress responses, hormone and nutrient signaling pathways, secondary metabolism and vegetative and reproductive development. Moreover, messenger RNA transcriptomic datasets from the same experiments shows a substantial reduction of photosynthesis- related genes and an induction of the genes and regulatory transcription factors involved in flavonoid pathway which was further evidenced by a very high accumulation of anthocyanin in all genotypes, especially pap1-D/MYB75 overexpression which showed some genotype-by-sucrose interaction effects. My sRNA-/mRNA-seq systems approach revealed evidence of a retrograde signaling mechanism from UCP family member proteins in the mitochondrial inner membrane to the genome-wide reprogramming of gene expression for carbon partitioning pathways from primary to secondary antioxidant metabolites, including post-transcriptional control.Embargo status: Restricted until 01/2025. To request the author grant access, click on the PDF link to the left
Role of miRNAs in carbon metabolism and stress responses in Arabidopsis thailiana mitochondrial uncoupling protein mutants ucp1/2/3 and activation-tagged transcription factor allele PRODUCTION OF ANTHOCYANIN PIGMENT/PAP1-D/MYB75
No full textPlant sugars, specifically the transported disaccharide primary product of photosynthesis sucrose, control multiple aspects of the plant life cycle including structure, growth, and development. Notably, sucrose functions as a signaling molecule by unknown molecular mechanisms to facilitate various stress adaptations. Accumulation of high sugar concentrations in plants is a hallmark associated with many environmental stimuli, abiotic, and biotic stresses, resulting in accumulation of antioxidant secondary carbon metabolites anthocyanins and flavanoids. From a regulatory perspective, some microRNAs (miRNAs) are potentially components of sucrose signaling pathways because of their established roles in secondary carbon metabolism. However, current understanding of the role of miRNAs in sucrose signaling pathway is very scarce. In this study, I endeavored to uncover the effect of exogenous high sucrose stress on miRNA profiles in Arabidopsis mitochondrial uncoupling protein mutants (ucp) that are defective in reactive oxygen species (ROS) homeostasis and pap1-D, a positive effector transgene mutant of secondary metabolite anthocyanin pathway. My aim is to better understand the UCP protein roles in response to oxidative stress and subject to regulatory control by sugar signaling, and to ascertain the importance of miRNAs impacting primary metabolism and regulation of carbon partitioning to the secondary metabolite pathways antioxidant anthocyanins and flavanols. Qualitative measurements of ROS hydrogen peroxide and superoxide abundance with specific chromogenic stains showed higher endogenous ROS in sucrose-treated samples. My analysis of small RNA deep sequencing datasets from sucrose-treated mutant and wild-type seedlings shows that high exogenous sucrose treatment altered the expression of many miRNAs inferred to be involved in primary metabolism, stress responses, hormone and nutrient signaling pathways, secondary metabolism and vegetative and reproductive development. Moreover, messenger RNA transcriptomic datasets from the same experiments shows a substantial reduction of photosynthesis- related genes and an induction of the genes and regulatory transcription factors involved in flavonoid pathway which was further evidenced by a very high accumulation of anthocyanin in all genotypes, especially pap1-D/MYB75 overexpression which showed some genotype-by-sucrose interaction effects. My sRNA-/mRNA-seq systems approach revealed evidence of a retrograde signaling mechanism from UCP family member proteins in the mitochondrial inner membrane to the genome-wide reprogramming of gene expression for carbon partitioning pathways from primary to secondary antioxidant metabolites, including post-transcriptional control
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
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