1,720,956 research outputs found
Capsid Assembly and Single Stranded DNA Genome Formation of Adeno-Associated Virus Type2 in Yeast Cells
Full text linkSaccharomyces cerevisiae has provided an array of genetic tools to study unknown aspects
of viral life cycles, supporting replication of many different RNA or DNA viruses (e.g. Tombusviruses or Papillomaviruses). It also provides means for up-scalable, cost- and time-effective production of various virus-like particles (e.g. Human Parvovirus B19 or Rotavirus) and as such represents a useful tool for vaccine development. To extend the utility of the S. cerevisiae expression system, we expressed AAV2 structural and nonstructural proteins in yeast cells, using both authentic AAV2 and heterologous yeast promoters. For the first time, we described the assembly of AAV2 virus-like particles from yeast-expressed AAV2 structural proteins. To do this we used AAV p40 promoter, whose activity in yeast cells resembled the one of yeast glycolytic promoters, resulting in the synthesis of the most abundant capsid protein VP3 when transformed yeast cells were
grown on glucose as a carbon source. The expression of other two VPs was induced from yeast, galactose inducible pGal1 promoter. Simultaneous production of all three VPs was achieved by growing the yeast cells in the medium containing both glucose and galactose, while their relative production levels were further optimized by varying amounts of each
carbon source in the induction medium, followed by the fine tuning of the induction time.
Moreover, we investigated the ability of the yeast Saccharomyces cerevisiae to carry out
the replication of a recombinant rAAV2. When a plasmid harboring the rAAV2 genome in
which the cap gene was replaced with the S. cerevisiae URA3 gene, was co-transformed in
yeast with a plasmid expressing Rep68 from constitutive yeast promoter pADH, a
significant number of URA3+ clones were scored (more than 30-fold over controls).
Molecular analysis of low molecular weight DNA revealed that the single stranded DNA is
formed, in Rep68 and ITR dependent manner, and that the plasmid is entirely replicated.
The ss DNA contained the ITRs, URA3 gene and also vector sequences suggesting that ss
rAAV genomes were not obtained by the canonical AAV replication mechanism.
These results could open new prospects for using yeast cell in two ways: (i) as a model
system for studying viral and cellular factors involved in AAV2 capsid assembly and
packaging of rAAV ss genomes; and (ii) as a novel cell factory for developing superior
recombinant rAAV production technologies
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
Draft Genome Sequence of the Probiotic Yeast Kluyveromyces marxianus fragilis B0399
Full text linkHere, we report the draft genome sequence of Kluyveromyces marxianus fragilis B0399, the first yeast approved as a probiotic for human consumption not belonging to the genus Saccharomyces The genome is composed of 8 chromosomes, with a total size of 11.44 Mb, including mitochondrial DNA
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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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