1,720,983 research outputs found
An Overview of the Potentialities of Antimicrobial Peptides Derived from Natural Sources
Full text linkAntimicrobial peptides (AMPs) are constituents of the innate immune system in every kind of living organism. They can act by disrupting the microbial membrane or without affecting membrane stability. Interest in these small peptides stems from the fear of antibiotics and the emergence of microorganisms resistant to antibiotics. Through membrane or metabolic disruption, they defend an organism against invading bacteria, viruses, protozoa, and fungi. High efficacy and specificity, low drug interaction and toxicity, thermostability, solubility in water, and biological diversity suggest their applications in food, medicine, agriculture, animal husbandry, and aquaculture. Nanocarriers can be used to protect, deliver, and improve their bioavailability effectiveness. High cost of production could limit their use. This review summarizes the natural sources, structures, modes of action, and applications of microbial peptides in the food and pharmaceutical industries. Any restrictions on AMPs’ large-scale production are also taken into consideration
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
Genotyping at the CSN1S1 locus by PCR-RFLP and AS-PCR in a Neapolitan Goat Population
Full text linkThe goat CSN1S1 gene has for many years been an excellent model for demonstrating that most of the variability observed in the as1-casein content in goat’s milk is due to the presence of autosomal alleles at a single structural locus. Until now, about 17 alleles associated to at least four levels of as1-casein expression in milk have been described at the CSN1S1 locus in the domestic goat (Capra hircus). The great importance of goat as1-casein polymorphism is due to its qualitative as well as quantitative implications. In the present work five PCR protocols (PCR-RFLPs, AS-PCR) were set up for rapid genotyping of B1, B2*, B3, B4 and C CSN1S1 alleles, until nowdetectable only by milk electrophoresis. Application of these protocols, together with previously described methods to identify CSN1S1 01, E, M, F, N and A* (CSN1S1 A, G, I, H) alleles, allow us to define, at DNA level, the genetic structure of the autochthonous goat reared in the province of Naples for the highest number of possible alleles at this locus. Monitoring of CSN1S1 variability in the Neapolitan goat population indicates a high frequency of low (F, 0.368) and null (N, 0.227) alleles
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
Gene structure analysis of caprine and ovine Mannose Binding Lectin (MBL)
No full textThe Mannose Binding Lectin (MBL) is an important factor of natural immunity which acts as a primordial antibody, capable to activate the complement and to link to some sugars (such as mannose) present on the surface of some bacteria as Brucella. In the present study, we report the partial structure of the gene coding for the MBL in sheep and goat as well as the analysis of their promoters. By using as template genomic DNA from leukocytes obtained from individual blood samples we sequenced from -961 nt of the promoter to the 397th nt of the 4th exon of four sheep (EMBL Acc. no. AM933378) and from -978 nt to the 471th nt of the 4th exon of four goats (EMBL Acc. no. AM933377), for a total of 4461 bp and 4515 bp, respectively. By comparing the homologous sequence of the bovine MBL gene (EMBL Acc. no. NC007327), it was possible to determine the size of the exons, similar in both investigated species: 200 bp (exon 1), 117 bp (exon 2), and 69 bp (exon 3). The comparison of the sequences between goat and sheep shows an homology of 92.2%. The differences are due essentially to insertions/deletions at intronic level: the sheep presents with respect to the goat a deletion at the 1st intron of 11 nt, two insertions at the 2nd intron, respectively of 29 and 41 nt, and at the 3rd intron a stretch of eight Guanine in the goat vs. eight Thymine in the sheep. The length of the three introns was 395 bp vs. 385 (intron 1), 1278 bp vs. 1347 (intron 2), and 1028 bp vs. 1019 (intron 3) respectively in goat and sheep. For both species, all the splice junctions follow the common role 5'GT/ 3'AG. The ORF (Open Reading Frame) encodes for 249 amino acid residues, whereas the leader peptide is composed by 19 amino acids. The starting codon (ATG, Methionine) is located between the 10th and the 12th nt of the 1st exon, while the stop codon (TGA) between the 372th and the 374th nt of the 4th exon. While from the comparison of the exonic sequences, 23 SNPs were identified, 10 of which give rise to an amino acidic change. The sequence analysis of the promoter region in sheep shows the presence of the following putative binding sites for transcription factors: TATA-box (ATAAA) and CCAAT-box (CCAAAT) in position -49 and -140 nt, respectively. Furthermore, two glucocorticoid responsive elements (GRE) were identified: in position -765 (AGATCAGA) and -971 (ACTGATCT). The promoter analysis for goat was found to be analogous to that of sheep but it shows the disappearance of the regulatory site GRE (ACTGATCT). Further studies need to be performed in order to verify whether the markers identified in the present study can be associated to the resistance to pathogens such as Brucella melitensis by carrying out suitable test for antimicrobial activity
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