1,721,696 research outputs found
Correction to: Bacterial association observations in Lucilia sericata and Lucilia cuprina organs through 16S rRNA gene sequencing (Applied Microbiology and Biotechnology, (2021), 105, 3, (1091-1106), 10.1007/s00253-020-11026-8)
No full textCorrection to: Bacterial association observations in Lucilia sericata and Lucilia cuprina organs through 16S rRNA gene sequencing (Applied Microbiology and Biotechnology, (2021), 105, 3, (1091-1106), 10.1007/s00253-020-11026-8
Molecular Cloning and Gene Expression of the Chitinase from Bacillus cereus BCRC 11026
No full text葡萄糖胺與幾丁寡糖為幾丁質 (chitin) 之水解產物，在許多工業及生物技術方面佔有重要角色。葡萄糖胺與幾丁寡糖可由幾丁質酶分解幾丁質而獲得，因而本研究主要之目的為純化、轉殖並於大腸桿菌系統表現仙人掌桿菌屬 Bacillus cereus BCRC 11026 中之幾丁質酶。實驗上自仙人掌桿菌屬之 B. cereus BCRC 11026 萃取粗蛋白，經硫酸銨沉澱、快速蛋白質液相層析及活性測試等步驟，分離出具有幾丁質分解能力之幾丁質水解酶，經由 SDS-PAGE 分析結果顯示蛋白質分子量約為 61 kDa，後續進行 N 端胺基酸序列分析，發現其 N 端胺基酸序列為 SDIKY。之後以 B. cereus BCRC 11026 之全 DNA 為模板，以N 端胺基酸序列搜尋基因庫所得之同源基因序列為引子進行聚合酶連鎖反應，獲得 B. cereus BCRC 11026 之幾丁質酶基因 GD1A4，並構築成含有幾丁質酶基因的質體 pET32a-GD1A。將 pET32a-GD1A 轉殖入 Escherichia coli BL-21 表現後，進行 SDS-PAGE 與 western blotting 分析，顯示此重組蛋白分子量約為 38.5 kDa。分析發現此重組幾丁質水解酶之純化倍率為 48.78，回收率為 1.67 %，比活性為 12.536 U/mg，其最適反應溫度約為 60℃，最適反應 pH 值為 6.0，在 60 ℃以下熱安定。此幾丁質水解酶可利用於葡萄糖胺與幾丁寡糖之生產。N-acetyl-D-glucosamine (GlcNAc) and N-acetyl chitooligosaccharides, the products of chitin, are important to several industries and biotechnology sectors. They could be hydrolyzed from chitin by chitinase. The aim of this study was to purify and clone the gene encoding chitinase from Bacillus cereus BCRC 11026 and to perform recombinant expression in a prokaryotic E. coli system. Chitinase was purified from B. cereus BCRC 11026 through ammonium sulfate fractionation and Mono S ion-exchange chromatography. Its molecular mass was about 61 kDa, as determined by SDS-PAGE. The N-terminal amino acid sequence of the purified chitinase was further determined. Cloning was carried out using PCR technique, using the homogeneous gene sequences of the purified chitinase as the primers. The chitinase fragment (GD1A4) amplified from the genomic DNA of B. cereus BCRC 11026 was ligated with pET-32a (+) vector to generate an expression vector, pET32a-GD1A4. In order to achieve successful expression of the recombinant chitinase, the plasmid pET32a-GD1A4 was then transferred into E. coli BL-21 to produce the recombinant protein with a molecular weight of 38.5 kDa. Furthermore, the recombinant chitinase were purified and concentrated by 48.78 fold with a recovery of 1.67 % and a specific activity of 12.536 U/mg. The optimal pH and temperature for the recombinant chitinase wase 6.0 and 60 ℃, respectively, and the enzyme activity was relatively stable below 60 ℃. This chitinase could be utilized for the production of N-acetyl-D-glucosamine and N-acetyl chitooligosaccharides.目錄、 中文摘要…………………………………………………………………… 1、 英文摘要…………………………………………………………………… 2、 研究目的…………………………………………………………………… 3、 研究背景…………………………………………………………………… 4 一、幾丁質與幾丁聚醣及其衍生物之介紹………………………………… 4 二、幾丁質酶與幾丁聚醣酶………………………………………………… 10 三、微生物幾丁質酶基因之選殖…………………………………………… 13、材料與方法…………………………………………………………………… 15 一、Bacillus cereus BCRC 11026幾丁質酶之純化……………………… 15 二、Bacillus cereus BCRC 11026幾丁質酶基因之選殖………………… 22、重組蛋白質生化性質分析……………………………………………… 33 、實驗結果…………………………………………………………………… 35 一、Bacillus cereus BCRC 11026 幾丁質酶之純化、檢定胺基酸序列之分析…………………………………………………… 35 二、幾丁質基因之選殖……………………………………………………… 36、以 Escherichia coli表現幾丁質酶之生化性質…………………… 41、討論…………………………………………………………………………… 43、引用文獻…………………………………………………………………… 45、圖表………………………………………………………………………… 5
Índice de higiene oral en niños de 8 a 10 años de la I.E.11026 Mariscal Cáceres, La Victoria, 2022
Get PDFLa presente investigación parte del problema; ¿Cuál es el Índice de higiene oral en
niños de 8 a 10 años de la I.E. 11026 Mariscal Cáceres, La Victoria, 2022, siendo su
objetivo general determinar el índice de higiene oral en niños de 8 a 10 años de la
I.E. 11026 Mariscal Cáceres, La Victoria, ¿2022? El presente estudio fue de tipo
cuantitativo con un diseño descriptivo transversal prospectivo. La población fueron
todos los niños de 8 a 10 años de la I.E "11026" Mariscal Andrés Avelino Cáceres
que hacen un total de 261; la muestra fue probabilística fue de 210 niños que
cumplieron los criterios de selección. El instrumento fue la ficha de recolección de
información usando el Índice de Higiene Oral Simplificado. Se obtuvo un IHOS
bueno en el 58,6%, 37,1% fue regular y 4,3% fue excelente. Concluyendo que el
Índice de Higiene Oral en nos niños de 8 a 10 años fue bueno.TesisCalidad de vida, promoción de la salud del individuo y la comunidad para el desarrollo de la sociedadAcceso y cobertura de los sistemas de atención sanitari
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
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