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Proteomic insights into the polyketide pathways of Monascus
No full text紅麴菌屬 (Monascus species) 能經由聚酮 (polyketide) 生成路徑產生具有生理活性的聚酮類二次代謝物；由於紅麴二次代謝相當複雜，目前對於聚酮生合成路徑之調控機制尚未明瞭。M. purpureus BCRC 31615、M. ruber BCRC 31534、M. pilosus BCRC 31526 以及 M. purpureus NTU 568 四種 Monascus 菌株可生產的二次代謝物種類及產量皆不相同，由本研究室所分離出的 M. purpureus NTU 568，在相同培養條件下，其黃色素 (monacin 與 ankaflavin) 產量高於其他菌株，而橘黴素 (citrinin) 產量則是低於 M. purpureus BCRC 31615；M. ruber BCRC 31534 和 M. pilosus BCRC 31526 雖然在 dextrin-MSG-mineral 培養基中不生成黃色素及橘黴素，但 M. ruber BCRC 31534 之紅色素產量顯著高於 M. pilosus BCRC 31526。各菌株 polyketide 產物量之差異，應與代謝途徑酵素調控有關。因此本研究藉由蛋白質體學方法，比較菌株間之蛋白質基礎表現量，藉以了解可能參與調控 polyketides 生成路徑之機制。和 M. purpureus BCRC 31615 相比，M. purpureus NTU 568 細胞中可能與 polyketide synthases (PKSs) 有關之蛋白質 monooxygenase 表現量相對較高，且同為二次代謝路徑之一的 mevalonate 生成路徑較不活絡；分支胺基酸代謝之相關蛋白質以及 aldehyde dehydrogenase (ALDH) 皆在 M. purpureus NTU 568 細胞中有較高之基礎表現量。分支胺基酸降解可產生 malonyl-CoA 或是 butanoyl-CoA，而 ALDH 表現量的上升則可增加 acetate 的產量，malonyl-CoA、butanoyl-CoA 以及 acetate 皆可作為合成 polyketides 的前趨物。當 NTU 568 培養於含有 4% 酒精之培養基時，其分支胺基酸代謝以及 ALDH 之蛋白表現量皆下降，且橘黴素以及黃色素產量被抑制，同時誘導熱衝擊反應 (heat shock response)。另外酒精也會抑制與 polyketides 生成相關之蛋白質 fatty acid synthases (FASs) 及 epoxide hydroxylase (EH) 之表現量，且 shikimate pathway 此二次代謝途徑亦受到抑制。紅色素產量較高之菌株 M. ruber BCRC 31534 和 M. pilosus BCRC 31526 相比，其 pyruvate dehydrogenase complex 表現量相對較高，可能使細胞產生較多的 acetyl-CoA；另外參與甘油代謝之蛋白質 dihydroxyacetone kinase 表現量則是較低，甘油代謝若較不活絡可能使細胞中累積較多甘油，進而增加 propionyl-CoA 的生成，acetyl-CoA 與 propionyl-CoA 皆可做為合成 polyketides 之前趨物。透過上述結果得知紅麴生成 polyketides 產量的高低，除了與本身參與二次代謝路徑之蛋白質表現量有關外，亦可透過改變一次代謝路徑，增加polyketides 之生成前趨物使 polyketides 產量上升。此研究結果對 Monascus 如何調控 polyketides 生成路徑有更進一步瞭解，並且提供增加紅麴 polyketides 之二次代謝物產量有用的資訊。Monascus species produce several potent bioactive metabolites through polyketide secondary metabolic pathways. However, there is little known about the metabolic regulation processes of Monascus. We observed that four strains, M. purpureus BCRC 31615, M. ruber BCRC 31534, M. pilosus BCRC 31526 and M. purpureus NTU 568, have different expression pattern of secondary metabolites inherently. M. purpureus NTU 568, isolated by our research group, could produce higher amount of yellow pigments than other Monascus strains but lower citrinin compared with M. purpureus BCRC 31615. On the other hand, M. ruber BCRC 31534 and M. pilosus BCRC 31526 produced red pigment instead of yellow pigment and citrinin in dextrin-MSG-mineral (DMM) medium cultivation. Furthermore, the production level of red pigment was higher in M. ruber BCRC 31534 compared with M. pilosus BCRC 31526. Assuming the different expression pattern of secondary metabolites might reflect on protein expression level of Monascus species identically, in order to understand the regulatory processes of polyketide pathway in Monascus, we used a comparative proteomic approach to identify proteins with significant expression change among different strains. The protein expression level of monooxygenase, the enzyme that might correlated with polyketide synthases, is higher in M. purpureus NTU 568 compared with M. purpureus BCRC 31615; meanwhile, mevalonate secondary metabolic pathway might be inactive. The proteins involved in branched-chain amino acids degradation, together with aldehyde dehydrogenase (ALDH), were expressed higher level basically in M. purpureus NTU 568. Malonyl-CoA and butanoyl-CoA, synthesized through BCAA degradation, and acetate, produced by ALDH, could be starter units of polyketides. However, after cultured in DMM medium containing 4% EtOH, M. purpureus NTU 568’s BCAA degradation and ALDH expression level were inversely down-regulated, the ability of producing yellow pigment and citrinin was inhibited, and heat shock response was induced as well. Furthermore, both polyketide synthesis related proteins fatty acid synthase and epoxide hydrolase and shikimate secondary metabolic pathway were inhibited by EtOH treatment. M. ruber BCRC 31534, higher red pigment producing strain, has higher expression level of pyruvate dehydrogenase complex compared with M. pilosus BCRC 31526, might resulted in increasing acetyl-CoA pool in cell. Moreover, the decreasing protein level of dihydroxyacetone kinase which participated in glycerol metabolism might result in propionyl-CoA synthesis. These results suggested that higher production of polyketide metabolites result from not only protein expression level of polyketide synthesis pathway, but also elevating starter units from primary metabolism as substrates for polyketide synthesis. This study provides further understanding of the polyketide secondary metabolism of Monascus, together with useful information to improve the production of bioactive secondary metabolites in Monascus species
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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