1,721,079 research outputs found
The effect of growth regulators and sucrose on anthocyanin production in Camptotheca acuminata cell cultures
No full textThe effect of different concentrations of growth regulators and sucrose on anthocyanin production in cell Suspension Cultures of Camptotheca acuminata Decaisne (Nyssaceae) was described for the first time and qualitatively and quantitatively evaluated. Anthocyanin production was significantly greater in the presence of kinetin, compared to benzyladenine, with the greatest concentration observed in the presence of 2 μ M kinetin. No significant differences in anthocyanin production were observed when comparing 2,4-dichlorophenoxyacetic acid to α-naphthaleneacetic acid, except when using 2 μ M, 2,4-dichlorophenoxyacetic acid, which resulted in greater anthocyanin production. High sucrose concentration enhanced the production of anthocyanins. Based on the absence of anthocyanin production in the dark, we concluded that light was essential for stimulating anthocyanin production. The optimised medium consisted of: 2 μ M kinetin, 2 PM 2,4-dichlorophenoxyacetic acid and 292 mM sucrose. HPLC/DAD and HPLC/MS analyses revealed that the main anthocyanin was Cy 3-O-galactoside and that the minor derivative was Cy 3-O-glucoside
Enhancement of Viniferin Production in Vitis vinifera L. cv. Alphonse Lavallee Cell Suspensions by Low-Energy Ultrasound Alone and in Combination with Methyl Jasmonate
No full textThis study examined for the first time the effect of low-energy ultrasound (US), used alone or in combination with methyl jasmonate (MeJA), on viniferin production in cell cultures of Vitis vinifera L. cv Alphonse Lavallee. Cell suspensions were exposed for 2 min to US (power 30, 60, and 90 mW cm(-3)). The highest viniferin production was obtained at 30 mW cm(-3). When sonication was performed twice, the effect on viniferin production was negligible, whereas triple sonication slightly increased production. US treatment at 30 mW cm(-3) for 5 min decreased viniferin production and induced cellular death. The combined use of MeJA and US (2 min) increased the production of delta-viniferin, the dominant stilbene, more than each elicitor used alone. These results suggest that low-energy US, alone and in combination with MeJA, can act as a physical elicitor to stimulate viniferin production in V. vinifera cell cultures
Effect of industrial processing parameters and storage on bioactive compounds of tomato sauce.
No full textTomato is among the most important diet source of bioactive substances such as carotenoids, especially lycopene, and phenolic compounds. The effect of industrial process parameters, in particular lethality (F100) and oBrix, and of storage for a period up to 24 months at Troom on bioactive compounds content and activity of tomato sauce was investigated. Total phenolic and lycopene content were not affected by the considered industrial process parameters and remained significantly unchanged during storage conditions. The specific antioxidant power decreased appreciably in the first months of storage and after 24 months it diminished by 27%
High-performance liquid chromatography/electrospray ionization tandem mass spectrometric investigation of stilbenoids in cell cultures of Vitis vinifera L., cv. Malvasia
No full textCell suspension cultures of Vitis vinifera L., particularly after elicitation, have shown the ability to biosynthesize several stilbenoids. In this work the application of specific tandem mass spectrometry (MS/MS) experiments and the integration with data from UV-vis spectra, available only for the main compounds of the extract, allowed the detection of over 20 different stilbenoids. Up to eight monoglicosides, both monomers and dimers, a high number of dimer forms (up to 17), belonging to the group of viniferins and to their oxidized derivatives, were identified in the extract of Malvasia cell cultures. Moreover, the selectivity and sensitivity of the method allowed detection also of a few cis derivatives (up to 3) present in very low concentrations and presumably produced by the light exposure during treatment of the sample. To the best of the authors' knowledge, there are no literature data on MS/MS experiments targeted to simultaneously study monomeric and dimeric stilbenoids, both as free and glycosilated forms, in a complex mixture from V. vinifera cell suspension cultures
Effects of Elicitors on the Production of Resveratrol and Viniferins in Cell Cultures of Vitis vinifera L. cv Italia
No full textMethyl jasmonate, jasmonic acid and chitosan were tested as elicitors on cell suspension cultures obtained from Vitis vinifera cv Italia to investigate their effect on stilbene production. Stilbene accumulation in the callus, grown under nonelicited conditions, was also investigated. Calli and cell suspensions were obtained in a B5 culture medium supplemented with 0.2 mg L(-1) NAA and 1 mg L(-1) KIN. Stilbene determination was achieved by HPLC/DAD/MS. Whereas callus biosynthesized only piceid, cell suspensions elicited with jasmonates produced several stilbenes, mainly viniferins. In suspended cells, methyl jasmonate and jasmonic acid were the most effective in stimulating stilbene biosynthesis, whereas chitosan was less effective; in fact, the amount of stilbenes obtained with this elicitor was not significantly different from that obtained for the control cells. The maximum production of total stilbenes was at day 20 of culture with 0.970 and 1.023 mg g(-1) DW for MeJA and JA, respectively
Anthocyanins and xanthones in the calli and regenerated shoots of Hypericum perforatum var. angustifolium (sin. Fröhlich) Borkh
No full textThe present paper reports on the production of anthocyanins and xanthones in different in vitro systems of Hypericum perforatum var. angustifolium (sin. Fröhlich) Borkh. Undifferentiated calli and regenerated shoots at different developmental stages were analyzed by applying an extractive and an analytical procedure capable of detecting and quantifying anthocyanins. The findings revealed, for the first time, the co-presence of hypericins and anthocyanins in shoots at initial and more developed stages of H. perforatum var. angustifolium L. Moreover, a high production of xanthones was found in the undifferentiated calli
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
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