1,720,972 research outputs found
The Role of Decapping Factors During Nonsense-Mediated Decay (NMD) in Aspergillus nidulans
No full textRNA degradation is ubiquitous and it is clear that it must be carefully controlled to accurately recognise and target appropriate transcripts. There are several pathways for mRNA degradation and decapping is one of the critical steps in determining transcript stability. The focus of this study was the identification and characterisation of factors involved in decapping and their involvement in nonsense-mediated mRNA decay (NMD) in Aspergillus nidulans. Our studies have shown that disruption of two decapping factors, Dcp1 and the Nudix protein Dcp2, lead only to partial suppression of NMD. This distinguishes A. nidulans from Saccharomyces cerevisiae, where the two decapping factors are required for NMD. Deletion of lsm1, which encodes a component of a heptomeric complex, Lsm1-7, a known promoter of decapping, also partially supressed NMD. To our knowledge this is the first time that the role of Lsm’s in NMD has been described. A similar result was observed when another Nudix family protein, NdxD, was disrupted. We propose that NdxD is a second decapping factor in A. nidulans. Disruption of other factors known to promote decapping and subsequent RNA degradation, Pat1, Dhh1 and Xrn1, did not affect NMD, demonstrating these factors are not required for NMD in A. nidulans. In order to quantify decapping, we set out to establish a simple and reliable assay to quantify the decapped transcripts. The method utilised splinted-ligation through which an RNA adaptor is ligated specifically to the 5’ end of decapped transcripts with the help of splint primer. The primer has a complementary sequences to the RNA adaptor at its 3’ end and the eight random nucleotides at the 5’ end to facilitate hybridisation to any decapped transcript. qRT-PCR was utilised to amplify the ligation products for a specific transcript and used internal primers as a control to assess the relative level of decapped transcripts. This gave a good basis for quantifying the decapped transcripts, however further optimisation is required in order to develop a robust assay. Although it has been known that both Dcp1 and Dcp2 form a decapping complex in yeast, our studies showed that Dcp2 has a significant role in stabilising the uaZ+ transcript, while deletion of dcp1 did not. Fluorescence microscopy has shown that both of these proteins localise primarily to the expected P-body like structures, however, the major proportions of Dcp2 and Dcp1 did not co-localise and were therefore not interacting. These data suggest that the Dcp2 activity is not solely dependent on Dcp1, suggesting a divergence between A. nidulans and S. cerevisiae. Additionally, confocal microscopy was used to characterise the intracellular distribution of CutA and CutB, which are involved in 3’ pyrimidine-tagging of transcripts, promoting decapping and degradation of mRNA. Using GFP and RFP tagged proteins, we determined that CutA is primarily localised in the cytoplasm whereas CutB is primarily, but not exclusively, located in the nuclei. Interestingly deletion of cutB lead to increased levels of CutA in the nuclei suggesting an interplay between the two proteins. Deletion of dcp1 produces an aberrant polysome profile as determined by sucrose gradient centrifugation. The predominant peak correlated with the large (60S) subunit rather than the monosome (80S) peak observed for WT. The small (40S) subunit was also relatively high. These observations distinguished ∆dcp1 from WT and the phenotype of the ∆dcp2 strain was intermediate between the two. The accumulation of 60S peak in ∆dcp1 included a relatively high proportion of 28S rRNA derived fragments. Northern analysis of these putative 60S degradation products and sequencing of two specific fragments suggest that in the ∆dcp1 strain the ribosomes are being cleaved, possibly as part of an rRNA turnover mechanism. Although genetic analysis showed that both ∆dcp2 and a point mutation, dcp2 E148Q, which is likely to disrupt the nuclease activity, are both epistatic to dcp1 with respect to this phenotype. Northern analysis indicates that the degradation products observed in ∆dcp1, ∆dcp2 and WT strains appear very similar, even though the levels vary dramatically. This implies that Dcp2 is probably not directly responsible for these cleavage events or it is one of a number of activities cleaving the rRNA in what appears to be a similar way
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
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
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