1,720,981 research outputs found
Antibacterial and haemolytic peptides containing D-alloisoleucine from the skin of Bombina variegata
No full textA family of bombinin-related peptides is present in the skin of Bombina variegata. These peptides contain 27 residues with Gly as N-terminus and display antimicrobial activity. From sequence analysis of the cDNAs encoding for the corresponding peptide precursors, the presence of a novel 20-residue peptide with Ile as N-terminus was predicted. We have now purified a family of hydrophobic peptides named H1-H5, whose sequences correspond to the predicted peptide with some variability in positions 1, 2 and 8. In particular, H3-H5 contain a D-alloisoleucine residue in the second position. All these peptides display antibacterial and haemolytic activity
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
BSTI, a trypsin inhibitor from skin secretion of Bombina bombina related to protease inhibitors of nematodes
No full textFrom skin secretions of the European frog Bombina bombina, a new peptide has been isolated that contains 60 amino acids, including 10 cysteine residues. Its sequence was determined by automated Edman degradation and confirmed by analysis of the cDNA encoding the precursor. A search in the databanks demonstrated that the pattern of cysteine residues in this skin peptide is similar to the ones found in protease inhibitors from Ascaris and in a segment of human von Willebrand factor. The 3D structure of the trypsin inhibitor from Ascaris suum could be used as a template to build a model of the amphibian peptide. In addition, we have demonstrated that this constituent of skin secretion is indeed an inhibitor of trypsin and thrombin, with K(i) values in the range of 0.1 to 1 microM. The new peptide was thus named BSTI for Bombina skin trypsin/thrombin inhibitor
Tachykinins and other biologically active peptides from the skin of the Costa Rican phyllomedusid frog Agalychnis callidryas.
No full textPeptides present in a methanol extract prepared from skin of the Costa Rican frog Agalychnis callidryas of the Phyllomedusinae subfamily were studied by sequence analysis and pharmacological tests. Members of five different peptide families-tachykinins, bradykinins, caerulein, opioid peptides and sauvagine-were found. In particular, the extract contained a number of tachykinins with the following sequences: Gly-Pro-Pro-Asp-Pro-Asn-Lys-Phe-Ile-Gly-Leu-Met-NH2, Gly-Pro-Pro-Asp-Pro-Asp-Arg(Lys)-Phe-Tyr-Pro-Gly-Met-NH2, pGlu-Pro-Asp-Pro-Asp-Arg-Phe-Tyr-Pro-Gly-Met-NH2, Gly-Pro-Pro-Asp-Pro-Asn-Lys-Phe-Tyr-Pro-Val-Met. The latter three peptides have the unusual C-terminal sequence Pro-Gly(or Val)-Met-NH2 rather than Gly-Leu-Met-NH2 found in many other members of the tachykinin family. The observed amino acid substitutions may be the reason for the marked decrease in the biological activity observed in all in vitro and in vivo tests, even through the spectrum of tachykinin activities was retained. A kassinin-like peptide, with the sequence Gly-Pro-Pro-Asp-Pro-Asn-Lys-Phe-Ile-Gly-Leu-Met-NH2, was also found in the A. callidryas skin. While kassinin has a much higher affinity for NK-3 than for NK-1 receptors, the opposite is true for this A. callidryas peptide. The extract from A. callidryas skin also contained a new caerulein (pGlu-Asp-Tyr(HSO3)-Lys-Gly-Trp-Met-Asp-Phe-NH2) and a phyllokinin (Arg-Pro-Hyp-Gly-Phe-Ser-Pro-Phe-Arg-Ile-Tyr), as well as the opioid peptides dermorphin and [Hyp6]dermorphin, both previously isolated from different Phyllomedusa species
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
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