1,720,963 research outputs found
Sisymbrium officinale, the Plant of Singers: A Review of Its Properties and Uses
No full textSisymbrium officinale (hedge mustard and formerly called Erysimum officinale) is a common plant in wild lands of Europe and Africa. It is also cultivated for its seeds and leaves to be used in salad or mustard. Sisymbrium officinale is useful not only in culinary preparations, but it also seems to possess interesting therapeutic properties, especially for throat diseases such as aphonia and hoarseness. For this reason, it is commonly called “herb of singers” (in Italian, “Erba dei cantanti”). Indeed a cup of Sisymbrium officinale infusion is frequently consumed by singers before artistic performance, even if its beneficial ability still needs to be scientifically demonstrated. Some preliminary data can be analyzed, but new efforts and resources should be devoted to study and investigate a plant with valuable therapeutic potential. This review summarizes the data available for Sisymbrium officinale
Plants as a Promising Reservoir of Tyrosinase Inhibitors
No full textThe process of melanogenesis, that takes place in the melanocytes of the epidermis, leads to hyperpigmentation. The biosynthetic pathway for production of melanin involves the enzyme tyrosinase that has been an attractive target for cosmaceutical research. Numerous synthetic, semisynthetic and natural, especially plant-based, inhibitors of tyrosinase have been reported in the literature. In plants, the secondary metabolites like flavonoids, chalcones, stilbenes, tannins, hydroquinone and kojic acid, etc... have been shown to possess the anti-tyrosinase activity. In the current review, we have covered the progress in this sphere that would be useful for not only further mechanistic investigations but also for the optimization of the structure of the metabolites for improved activity and selectivity. Thus the review presents a comprehensive report on tyrosinase inhibitors of plant origin reported in the extract form or as isolated compounds. Huge gap has been found between research and industry due to inconsistent pursual of the potent plant based extracts. There is a need to completely evaluate the extracts for structure optimization using molecular docking and evaluation of the safety inorder to benefit the industry with non toxic biological friendly products through invivo and exvivo optimization
The success in the short-distance communication for mating does not depend on chemical signals in the crustacean decapod Procambarus clarkii (Girard, 1852)
Get PDFPheromone-driven sex recognition has been widely documented in crayfish and a great deal of evidence supports the involvement of pheromones in their mating behaviour. This study investigates whether sexual interaction and mating success in the red swamp crayfish Procambarus clarkii are dependent on short-distance chemical communication between sexes, mediated by urine-borne pheromones. We compared the mating behaviour of intact animals that could release urine to chemically communicate in a natural way with that of urine-blocked animal pairs, for which chemical communication was precluded. Our results show that urine-borne pheromones are not critical for the reproductive success of P. clarkii, at least over the short-range distance (<1 m) considered in this study, during which the animals were confined in a restricted tank, facing one each other, and thus able to promptly mate. Under these experimental conditions, a lack of urine release neither precluded the occurrence, nor affected the duration of the different phases of mating behaviour. We conclude that short-distance chemical communication in P. clarkii is not a prerequisite for mating, and suggest that it could be affected by alternative sensory modalities, likely vision and/or acoustic signalling
Proteinaceous inhibitors of α-amylase and α-glucosidase from common bean (Phaseolus vulgaris L.): biochemical characterization and phylogenetic analysis of Sardinian cultivars
Get PDFThe common bean Phaseolus vulgaris is a good source of protein fiber and bioactive compounds. Among these proteinaceous α-amylase inhibitors (α-AIs) and α-glucosidase inhibitor could play an important role in weight loss and control of glycemic index above all in overweight and diabetic subjects.
In this study 10 poorly studied Italian P. vulgaris cultivars were screened about their
content in α-amylase/glucosidase inhibitors, antinutritional factor phytohemagglutinin
(PHA), and about the expression of α-AI gene and their phylogenetic relationship.
All the cultivars presented α-glucosidase inhibitor activity, while α-AI was missing in
two of them. Only Nieddone cultivar (ACC177) had no hemagglutination activity and its
α-AI was extracted, purified and characterized.
The purified inhibitor has a tetrameric structure with a molecular weight of about 42 kDa,
a temperature optimum of about 40°C and two pH optima (5 and 6.5).
Thermal stability is remarkably important, since the inhibitory activity was maintained at
25% after 5 hours of incubation at 100°C. The purified inhibitor had the highest affinity toward insect α-amylase about 3-fold more susceptible than human salivary amylase and porcine pancreatic α-amylase.
The kinetic characterization showed a mixed-type inhibition, suggesting a multiple site protein/protein interaction between enzyme (α-amylase) and inhibitor.
Molecular studies showed that α-AI is expressed in all cultivars and a close similarity between the two cultivars Pisu Grogu and Fasolu α-AI and isoform α-AI-4 emerged from the comparison of the partially reconstructed primary structures.
Moreover, from mechanistic models emerge the interaction network that connects the αAI with the α-amylase enzymecharacterized from two interaction hotspots (Asp38, and Tyr186), giving some insights for the analysis of α-AI primary structure from the different cultivars, particularly about structure-activity relationship.
This study can be lay the basis for increase the knowledge about this class of proteins and developing commercial preparations from Italian common beans cultivars
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Biochemical and Phylogenetic Analysis of Italian Phaseolus vulgaris Cultivars as Sources of α-Amylase and α-Glucosidase Inhibitors
Get PDFPhaseolus vulgaris α-amylase inhibitor (α-AI) is a protein that has recently gained commercial interest, as it inhibits mammalian α-amylase activity, reducing the absorption of dietary carbohydrates. Numerous studies have reported the efficacy of preparations based on this protein on the control of glycaemic peaks in type-2 diabetes patients and in overweight subjects. A positive influence on microbiota regulation has also been described. In this work, ten insufficiently studied Italian P. vulgaris cultivars were screened for α-amylase- and α-glucosidase-inhibiting activity, as well as for the absence of antinutritional compounds, such as phytohemagglutinin (PHA). All the cultivars presented α-glucosidase-inhibitor activity, while α-AI was missing in two of them. Only the Nieddone cultivar (ACC177) had no haemagglutination activity. In addition, the partial nucleotide sequence of the α-AI gene was identified with the degenerate hybrid oligonucleotide primer (CODEHOP) strategy to identify genetic variability, possibly linked to functional α-AI differences, expression of the α-AI gene, and phylogenetic relationships. Molecular studies showed that α-AI was expressed in all the cultivars, and a close similarity between the Pisu Grogu and Fasolu cultivars’ α-AI and α-AI-4 isoform emerged from the comparison of the partially reconstructed primary structures. Moreover, mechanistic models revealed the interaction network that connects α-AI with the α-amylase enzyme characterized by two interaction hotspots (Asp38 and Tyr186), providing some insights for the analysis of the α-AI primary structure from the different cultivars, particularly regarding the structure–activity relationship. This study can broaden the knowledge about this class of proteins, fuelling the valorisation of Italian agronomic biodiversity through the development of commercial preparations from legume cultivars
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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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