1,721,226 research outputs found
Amino acid supplements improve native antioxidant enzyme expression in the skeletal muscle of diabetic mice
No full textOxidative stress plays an important role in the pathogenesis of diabetic complications. We investigated the effects of a specific oral mixture of amino acid (AA) supplements on the antioxidant defense system, superoxide dismutase (SOD), and heat shock proteins (HSPs: HspB1, similar to Hsp 20 kDa, and HspB7) in the soleus muscle of streptozotocin (STZ)-diabetic mice by bidimensional electrophoresis and mass spectrometry. Four groups of 5 mice were considered: nondiabetic control mice, nondiabetic mice given AA supplements (0.1 g/kg per day for 15 days), diabetic mice (induced with STZ 65 mg/kg), and diabetic mice given AAs. AA supplements in the nondiabetic animals were associated with a statistical increase of SOD and no changes in expression of HSPs. Diabetes mellitus decreased antioxidant SOD and increased cellular stress as demonstrated by the overall upregulated HSPs. Administration of AAs counteracted the effects of diabetes, producing upregulation of SOD and downregulation of HSPs. These data suggest a role for AA supplements in controlling the antioxidant defense system and reducing the oxidative stress in diabetic skeletal muscle
Searching for specific motifs in affinity capture in proteome analysis
No full textIn analysing the red blood cell cytoplasmic proteome, in search for low abundance proteins, 15 amino acid (AA; Arg, Asn, Asp, Gln, Gly, His, Ile, Lys, Phe, Pro, Ser, Thr, Trp, Tyr, and Val) probes, used individually, captured a total of 787 unique gene products. Of those, 76 were found to be the common catch of all AA probes, 497 were captured by more than one (but not all) probe, and 214 were captured by only one probe. By using the InterPro database, for 151 of the 214 IPIs associated with proteins captured by a single amino acid, we have found 265 annotations of motifs (231 protein domains, 3 binding sites, 3 active sites, 13 conserved sites, and 15 repeats). Among these 151 proteins annotated, there are 75 domains, 2 active sites, 5 conserved sites, and 3 repeats (a total of 85 motifs) that are at all effects amino acid strictly specific. As a result of these findings, these 85 amino acid specific motifs singled out 40 (18.69%) of the total list of 214 proteins representing the total capture of the 15 AAs here reported. If one considers that only for 151 (70.56%) of the 214 proteins data about interacting motifs could be collected, the percentage of proteins for which the 85 amino acid strictly specific motifs have been found increases to the even more relevant value of 26.49%. The identified motifs can partially explain the exclusive protein capture of the 15 amino acid probes. The unique general and specific capturing ability of two of these AA probes, Phe and Arg, is evaluated, discussed and put in perspective
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
Purified box C/D snoRNPs are able to reproduce site-specific 2'-O-methylation of target RNA in vitro
No full textSmall nucleolar RNAs (snoRNAs) are associated in ribonucleoprotein particles localized to the nucleolus (snoRNPs). Most of the members of the box C/D family function in directing site-specific 2′-O-methylation of substrate RNAs. Although the selection of the target nucleotide requires the antisense element and the conserved box D or D′ of the snoRNA, the methyltransferase activity is supposed to reside in one of the protein components. Through protein tagging of a snoRNP-specific factor, we purified to homogeneity box C/D snoRNPs from the yeast Saccharomyces cerevisiae. Mass spectrometric analysis demonstrated the presence of Nop1p, Nop58p, Nop56p, and Snu13p as integral components of the particle. We show that purified snoRNPs are able to reproduce the site-specific methylation pattern on target RNA and that the predicted S-adenosyl-l-methionine-binding region of Nop1p is responsible for the catalytic activity
Engineering of Lactobacillus jensenii to secrete RANTES and a CCR5 antagonist analogue as live HIV-1 blockers
No full textThe development of effective microbicides for the prevention of HIV-1 sexual transmission represents a primary goal for the control of AIDS epidemics worldwide. A promising strategy is the use of bacteria belonging to the vaginal microbiota as live microbicides for the topical production of HIV-1 inhibitors. We have engineered a human vaginal isolate of Lactobacillus jensenii to secrete the anti-HIV-1 chemokine RANTES, as well as C1C5 RANTES, a mutated analogue that acts as a CCR5 antagonist and therefore is devoid of proinflammatory activity. Full-length wild-type RANTES and C1C5 RANTES secreted by L. jensenii were purified to homogeneity and shown to adopt a correctly folded conformation. Both RANTES variants were shown to inhibit HIV-1 infection in CD4+ T cells and macrophages, displaying strong activity against HIV-1 isolates of different genetic subtypes. This work provides proof of principle for the use of L. jensenii-produced C1C5 RANTES to block HIV-1 infection of CD4+ T cells and macrophages, setting the basis for the development of a live anti-HIV-1 microbicide targeting CCR5 in an antagonistic manner. Copyright © 2010, American Society for Microbiology. All Rights Reserved
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