1,721,236 research outputs found
New anthracycline metabolites produced by the aklavinone 11-hydroxylase gene in Streptomyces galilaeus ATCC 31133
No full textTransformation of Streptomyces galilaeus ATCC 31133 with the aklavinone 11-hydroxylase gene (dnr F) resulted in the production of many red pigments. The new metabolites were purified and their structures were determined as 11-hydroxylated aclacinomycin A, B and T by spectral analysis. This result indicated that the dnrF was stably expressed in the strain S. galilaeus ATCC 31133 to give rise to hybrid aclacinomycins. In addition, a new aclacinomycin analog named 11-hydroxyaclacinomycin X was isolated from the same culture. Its structure was elucidated as 2'''amino-11-hydroxyaclacinomycin Y. It showed strong cytotoxicity against several human tumor cell lines, especially leukemia and melanoma cell lines
New anthracycline metabolites produced by the aklavinone 11-hydroxylase gene in Streptomyces galilaeus ATCC 31133
No full textTransformation of Streptomyces galilaeus ATCC 31133 with the aklavinone 11-hydroxylase gene (dnrF) resulted in the production of many red pigments. The new metabolites were purified and their structures were determined as 11-hydroxylated aclacinomycin A, B and T by spectral analysis. This result indicated that the dnrF was stably expressed in the strain S. galilaeus ATCC 31133 to give rise to hybrid aclacinomycins. In addition, a new aclacinomycin analog named 11-hydroxyaclacinomycin X was isolated from the same culture. Its structure was elucidated as 2'''-amino-11-hydroxyaclacinomycin Y. It showed strong cytotoxicity against several human tumor cell lines, especially leukemia and melanoma cell lines.open
Expression of Streptomyces peucetius genes for doxorubicin resistance and aklavinone 11-hydroxylase in Streptomyces galilaeus ATCC 31133 and production of a hybrid aclacinomycin
No full textThe aklavinone 11-hydroxylase gene and two doxorubicin resistance genes cloned from Streptomyces peucetius subsp. caesius ATCC 27952 were introduced into doxorubicin-sensitive Streptomyces galilaeus ATCC 31133, an aclacinomycin producer. The doxorubicin resistance genes drrA and drrB endowed S. galilaeus with high-level resistance to doxurubicin, indicating that the resistance mechanism for doxorubicin might be different from that for aclacinomycin A. Transformation of S. galilaeus ATCC 31133 with plasmid pMC213 containing the aklavinone 11-hydroxylase gene (dnrF) resulted in the production of many red pigments. A new metabolite was purified, and the position of the newly introduced hydroxyl group was determined. This result indicated that the aklavinone 11-hydroxylase gene was stably expressed in S. galilaeus ATCC 31133 and that it gave rise tn a hybrid aclacinomycin A which showed highly specific in vitro cytotoxicity against leukemia and melanoma cell lines.open
Aclacinomycin X, a novel anthracycline antibiotic produced by Streptomyces galilaeus ATCC 31133
No full textA new anthracycline antibiotic, designated as aclacinomycin X, was isolated from the culture broth of Streptomyces galilaeus ATCC 31133, and was identified as 7-(O-rhodosaminyl-deoxyfucosyl-red-nosyl)- aklavinone. Its in vitro cytotoxicity was tested against several human tumor cell lines.open
Aclacinomycin X, a novel anthracycline antibiotic produced by Streptomyces galilaeus ATCC 31133
No full textA new anthracycline antibiotic, designated as aclacinomycin X, was isolated from the culture broth of Streptomyces galilaeus ATCC 31133, and was identified as 7-(O-rhodosaminyl-deoxyfucosyl-rednosyl)-aklavinone. Its in vitro cytotoxicity was tested against several human tumor cell lines
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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