1,720,959 research outputs found
Sequencing and Characterization of αs2-Casein Gene (CSN1S2) in the Old-World Camels Have Proven Genetic Variations Useful for the Understanding of Species Diversification
No full textThe CSN1S2 gene encodes αs2-casein, the third most abundant protein in camel milk. Despite its importance in foals, human nutrition, and dairy processing, the CSN1S2 gene in camels has received little attention. This study presents the first complete characterization of the CSN1S2 gene sequence in Old-World camels (Camelus bactrianus and Camelus dromedarius). Additionally, the gene promoter, consisting of 752 bp upstream of exon 1, was analyzed. The entire gene comprises 17 exons, ranging in length from 24 bp (exons 4, 8, 11, and 13) to 280 bp (exon 17). Interesting was the identification of the exon 12 in both species. The promoter analysis revealed 24 putative binding sites in the Bactrian camel and 22 in dromedary camel. Most of these sites were typical elements associated with milk protein, such as C/EBP-α, C/EBP-β, Oct-1, and AP1. The SNP discovery showed relatively high genetic diversity compared to other camel casein genes (CSN1S1, CSN2, and CSN3), with a total of 34 polymorphic sites across the two species. Particularly noteworthy is the transition g.311G>A in the CSN1S2 promoter, creating a new putative consensus binding site for a C/EBP-β in the Bactrian camel. At the exon level, two novel variants were found. One was detected in exon 6 of the Bactrian camel (g.3639C>G), resulting in an amino acid replacement, p.36Ile>Met. The second variant was found in noncoding exon 17 of dromedary CSN1S2 (g.1511G>T). Although this mutation occurs in the 3'-UnTranslated Region, it represents the first example of exonic polymorphism in the CSN1S2 for this species. This SNP also affects the binding sites of different microRNAs, including the seed sequence of the miRNA 4662a-3p, highlighting its role as a regulatory factor for CSN1S2 gene. A PCR-RFLP was set up for genotyping a dromedary Tunisian population (n = 157), and the minor allele frequency was found to be 0.27 for the G allele, indicating a potential yield improvement margin. The interspersed elements (INEs) analysis revealed 10 INEs covering 7.34% and 8.14% of the CSN1S2 sequence in the Bactrian and dromedary camels, respectively. Furthermore, six elements (A, B, F, H, I, and L) are shared among cattle and camels and are partially found in other ruminants, suggesting a common ancestral origin of these retrotransposons. Conversely, elements C, D, E, and G are specific to camels
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
Genetic variability among and within domestic Old and New World Camelids at the α-lactalbumin gene (LALBA) reveals new alleles and polymorphisms responsible of differential expression
No full textα-Lactalbumin (α-LA), which is encoded by the
LALBA gene, is a major whey protein that binds to
Ca2+ and facilitates lactose synthesis as a regulatory
subunit of the synthase enzyme complex. In addition, it
has been shown to play central roles in immune modu lation, cell-growth regulation, and antimicrobial activ ity. In this study, a multitechnical approach was used
to fully characterize the LALBA gene and its variants
in both coding and regulatory regions for domestic ca melids (dromedary, Bactrian camel, alpaca, and llama).
The gene analysis revealed a conserved structure among
the camelids, but a slight difference in size (2,012 bp
on average) due to intronic variations. Promoters were
characterized for the transcription factor binding sites
(11 found in total). Intraspecies sequence comparison
showed 36 SNPs in total (2 in the dromedary, none in the
Bactrian camel, 22 in the alpaca, and 12 in the llama),
whereas interspecies comparison showed 86 additional
polymorphic sites. Eight SNPs were identified as trans specific polymorphisms, and 2 of them (g.112A>G and
g.1229A>G) were particularly interesting in the New
World camels. The first creates a new binding site for
transcription factor SP1. An enhancing effect of the
g.112G variant on the expression was demonstrated by
3 independent pGL3 gene reporter assays. The latter
is responsible for the p.78Ile>Val AA replacement and
represents novel allelic variants (named LALBA A and
B). A link to protein variants has been established by
isoelectric focusing (IEF), and bioinformatics analysis
revealed that carriers of valine (g.1229G) have a higher
glycosylation rate. Genotyping methods based on restriction fragment length polymorphism (PCR-RFLP)
were set up for both SNPs. Overall, adenine was more frequent (0.54 and 0.76) at both loci. Four haplotypes
were found, and the AA and GA were the most com mon with a frequency of 0.403 and 0.365, respectively.
Conversely, a putative biological gain characterizes
the haplotype GG. Therefore, opportunities for rapid
directional selection can be realized if this haplotype
is associated with favorable milk protein properties.
This study adds knowledge at the gene and protein
level for α-LA (LALBA) in camelids and significantly
contributes to a relatively unexplored research area in
these specie
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
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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