1,721,302 research outputs found
Chemical partitioning and DNA fingerprinting of some pistachio (Pistacia vera L.) varieties of different geographical origin
Get PDFThe genus Pistacia (Anacardiaceae family) is represented by several species, of which only P. vera L. produces edible seeds (pistachio). Despite the different flavor and taste, a correct identification of pistachio varieties based on the sole phenotypic character is sometimes hard to achieve. Here we used a combination of chemical partitioning and molecular fingerprinting for the unequivocal identification of commercial pistachio seed varieties (Bronte, Kern, Kerman, Larnaka, Mateur and Mawardi) of different geographical origin. The total phenolic content was higher in the variety Bronte followed by Larnaka and Mawardi cultivars. The total anthocyanin content was higher in Bronte and Larnaka varieties, whereas the total proanthocyanidin content was higher in Bronte, followed by Mawardi and Larnaka varieties. HPLC-DAD-ESI-MS/MS analyses revealed significant (P < 0.05) higher amounts of cyanidin-3-glucoside, idein, eryodictol-7-galactoside, quercetin-3-glucoside, luteolin-glucoside and marein in the variety Bronte, whereas higher amounts of peonidin-3-glucoside, okanin 4′-galactoside, hyperoside and quercetin-4′-glucoside were found in the variety Larnaka. The highest content of catechin was found in the Mawardi variety. A significantly (P < 0.05) higher total amount of fatty acids was found in the varieties Mateur, Kern and Bronte, followed by the varieties Larnaka and Mawardi, whereas the variety Kerman showed the lowest total fatty acid content. GC-FID and GC-MS analyses revealed the presence of several polyunsaturated fatty acids. Kern and Mateur varieties showed a significantly (P < 0.05) higher amount of linoleic acid, whereas the variety Bronte showed the highest amount of oleic acid. Molecular fingerprinting was achieved by ITS DNA PCR-RFLP analysis. Three different restriction enzymes (RsaI, TaqαI and PstI) were used to selectively cleave the resulting amplicons. A TaqαI site could be selectively found in the varieties Kerman, Larnaka and Mateur, whereas the digestion of the PCR products by RsaI gave specific patters exclusively on Bronte and Mawardi. Digestion by PstI gave specific patters exclusively on the Kern variety. The results showed that the Mediterranean varieties (Mateur, Bronte and Larnaka) show similar chemical patterns and (particularly for Mateur and Larnaka) a close phylogenetic relationship, allowing a chemical and molecular partitioning with respect to the other varieties
Tackling the Future Pandemics: Broad-Spectrum Antiviral Agents (BSAAs) Based on A-Type Proanthocyanidins
Get PDFA-type proanthocyanidins (PAC-As) are plant-derived natural polyphenols that occur as oligomers or polymers of flavan-3-ol monomers, such as (+)-catechin and (−)-epicatechin, connected through an unusual double A linkage. PAC-As are present in leaves, seeds, flowers, bark, and fruits of many plants, and are thought to exert protective natural roles against microbial pathogens, insects, and herbivores. Consequently, when tested in isolation, PAC-As have shown several biological effects, through antioxidant, antibacterial, immunomodulatory, and antiviral activities. PAC-As have been observed in fact to inhibit replication of many different human viruses, and both enveloped and non-enveloped DNA and RNA viruses proved sensible to their inhibitory effect. Mechanistic studies revealed that PAC-As cause reduction of infectivity of viral particles they come in contact with, as a result of their propensity to interact with virion surface capsid proteins or envelope glycoproteins essential for viral attachment and entry. As viral infections and new virus outbreaks are a major public health concern, development of effective Broad-Spectrum Antiviral Agents (BSAAs) that can be rapidly deployable even against future emerging viruses is an urgent priority. This review summarizes the antiviral activities and mechanism of action of PAC-As, and their potential to be deployed as BSAAs against present and future viral infections
Astaxanthin and eicosapentaenoic acid production by S4, a new mutant strain of Nannochloropsis gaditana
Get PDFBACKGROUND: Astaxanthin is a ketocarotenoid with high antioxidant power used in different fields as healthcare, food/feed supplementation and as pigmenting agent in aquaculture. Primary producers of astaxanthin are some species of microalgae, unicellular photosynthetic organisms, as Haematococcus lacustris. Astaxanthin production by cultivation of Haematococcus lacustris is costly due to low biomass productivity, high risk of contamination and the requirement of downstream extraction processes, causing an extremely high price on the market. Some microalgae species are also primary producers of omega-3 fatty acids, essential nutrients for humans, being related to cardiovascular wellness, and required for visual and cognitive development. One of the main well-known producers of omega-3 fatty eicosapentaenoic acid (EPA) is the marine microalga Nannochloropsis gaditana (named also Microchloropsis gaditana): this species has been already approved by the Food and Drug Administration (FDA) for human consumption and it is characterized by a fast grow phenotype. RESULTS: Here we obtained by chemical mutagenesis a Nannochloropsis gaditana mutant strain, called S4, characterized by increased carotenoid to chlorophyll ratio. S4 strain showed improved photosynthetic activity, increased lipid productivity and increased ketocarotenoids accumulation, producing not only canthaxanthin but also astaxanthin, usually found only in traces in the WT strain. Ketocarotenoids produced in S4 strain were extractible in different organic solvents, with the highest efficiency observed upon microwaves pre-treatment followed by methanol extraction. By cultivation of S4 strain at different irradiances it was possible to produce up to 1.3 and 5.2 mgL(−1) day(−1) of ketocarotenoids and EPA respectively, in a single cultivation phase, even in absence of stressing conditions. Genome sequencing of S4 strain allowed to identify 199 single nucleotide polymorphisms (SNP): among the mutated genes, mutations in a carotenoid oxygenase gene and in a glutamate synthase gene could explain the different carotenoids content and the lower chlorophylls content, respectively. CONCLUSIONS: By chemical mutagenesis and selection of strain with increased carotenoids to chlorophyll ratio it was possible to isolate a new Nannochloropsis gaditana strain, called S4 strain, characterized by increased lipids and ketocarotenoids accumulation. S4 strain can thus be considered as novel platform for ketocarotenoids and EPA production for different industrial applications. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12934-022-01847-9
Coffea arabica
No full text<i>2.3. In vitro antioxidant capacity of C. arabica and C. canephora</i> <p> In order to assess the antioxidant capacity of the green coffee extracts, we evaluated their reducing power by ferric thiocyanate assay and the free radical scavenging activities by DPPH radical assay. In general, the extracts were more active as antioxidants when tested by the reducing power assay (Fig. 5), since the steric accessibility of DPPH nitrogen-centered radical strongly affects the reaction rate of antioxidant compounds (Prior et al., 2005). Fig. 5 depicts the scatter plot of IC 50 values from both tests. As expected, the four <i>C. canephora</i> accessions showed the highest antioxidant activity (lowest IC 50 values for both assays) with respect to all other accessions. Although weaker than chlorogenic acid (Zhao et al., 2015), caffeine as well possesses antioxidant capacity, as recently demonstrated in <i>in vivo</i> experiments (Tsoi et al., 2015). Therefore, the higher content of both chlorogenic acids and caffeine correlates with a higher antioxidant capacity.</p> <p> Among the <i>C. arabica</i> accessions, the samples from Kenya showed the highest antioxidant capacity, followed by one of the accessions from Peru (A-Peru2) and one from Honduras (A-Honduras2). The lowest antioxidant capacity was observed in the Ethiopian (A-Ethiopia) and Guatemala (A-Guatemala) accessions, whereas intermediate antioxidant activities were observed for the remaining green coffee accessions.</p>Published as part of <i>Babova, Oxana, Occhipinti, Andrea & Maffei, Massimo E., 2016, Chemical partitioning and antioxidant capacity of green coffee (Coffea arabica and Coffea canephora) of different geographical origin, pp. 33-39 in Phytochemistry 123</i> on page 37, DOI: 10.1016/j.phytochem.2016.01.016, <a href="http://zenodo.org/record/10485263">http://zenodo.org/record/10485263</a>
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
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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