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  • 1
    Electronic Resource
    Electronic Resource
    Factors affecting callus and shoot formation from in vitro cultures of Lens culinaris Medik. (1988)
    Springer
    Plant cell, tissue and organ culture 15 (1988), S. 175-182 
    Details
    ISSN: 1573-5044
    Keywords: lentil ; in vitro culture ; callus formation ; shoot formation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The influence of culture medium and explant on callus and shoot formation of lentil (Lens culinaris Medik.) has been studied. Three different explants (shoot-tip, first node and first pair of leaves) from three Spanish lentil cultivars were cultivated on two basal media: Murashige and Skoog medium (MS) and medium with mineral salts of MS medium plus vitamins of Gamborg's B5 medium (MSB), supplemented with growth regulators. Media with 2,4-D induced the formation of calli in all explants, but no organ regeneration was obtained from these calli. Multiple shoot formation was obtained from 33% to 92% of the explants in media supplemented with 2.25 mg l−1 of BA and 0.186 mg l−1 NAA+2.25 mg l−1 BA; in the other media one to two shoots per explant were formed in 10 to 98% of the explants. Root formation from explants was achieved only in media with NAA or IAA. Of the explants tested, the best morphogenetic responses were obtained from nodes and the poorest from leaves.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00035759
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  • 2
    Electronic Resource
    Electronic Resource
    Somatic embryogenesis, plant regeneration and somaclonal variation in barley (1992)
    Springer
    Plant cell, tissue and organ culture 28 (1992), S. 97-101 
    Details
    ISSN: 1573-5044
    Keywords: epigenetic changes ; Hordeum vulgare ; in vitro culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In vitro culture of immature embryo and young leaf tissues was carried out with five cultivars of barley, Hordeum vulgare. Two cultivars (Albacete and Porthos) responded poorly from both types of explants, while the three others (Dissa, Golden Promise and Ingrid) produced a high frequency of embryogenic callus from these explants (25–60%). For ‘Dissa’ and ‘Ingrid’, young leaf explants were slightly better than immature embryo explants for embryogenic callus induction, while immature embryo cultures of ‘Golden Promise’ responded better than young leaf explants. Thus, there appears to be a significant genotype × explant interaction in the initiation of embryogenic callus in barley. Some phenotypic variants were detected among the regenerated plants of ‘Golden Promise’ and ‘Ingrid’, most originating by epigenetic changes. Only in one case was the variant phenotype heritable, probably due to a mutation in the chloroplast DNA. Mitotic alteractions were not detected. Consequently, somaclonal variation did not appear to be a very frequent event in plants regenerated from 1- to 6- month-old cultures of barley.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00039921
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  • 3
    Electronic Resource
    Electronic Resource
    Voltammetric determination of the antioxidant tert-butylhydroxytoluene (BHT) at a carbon paste electrode modified with nickel phthalocyanine (1994)
    Weinheim : Wiley-Blackwell
    Electroanalysis 6 (1994), S. 475-479 
    Details
    ISSN: 1040-0397
    Keywords: Modified electrode ; Electrocatalysis ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The voltammetric behaviar of the antioxidant tert-butyltydroxytoluene (BHT) at a carbon paste electrode modified with nickel phthalocyanine is described, and method for the determination of this antioxidant based on its oxidations at the modified electrode it proposed. Cyclic voltammograms showed a well defined oxidations peak for BHT at potentials approximately. 200 mV lower than the poorly defined peck obtained in the absence of the electocatalyst. A 35%, methanol :water medium, a modifier concentrations of 2%, and pH 2 were chosen as working conditions. Results obtained suggest that the oxidation signal arisen as a result of BHT chemically reducing Ni(II)to Ni(I) in the phthalocyanine, and the subsequent electrochemical oxidations of the latter. Using differential pulse voltammetry at ΔE =50 mV, a linear calibration range was obtained between 1 and 50 mg L-1 BHT with a detection limit of 0.17 mg L-1 BHT interferences from other substances commonly present in commercial antioxidant mixtures were tested. The developed method was applied to the determinations of BHT in stabilized diethyl ether.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elan.1140060519
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  • 4
    Electronic Resource
    Electronic Resource
    Electroanalytical study of the antioxidant tert-butylhydroquinone (TBHQ) in an oil-in-water emulsified medium (1994)
    Weinheim : Wiley-Blackwell
    Electroanalysis 6 (1994), S. 1014-1019 
    Details
    ISSN: 1040-0397
    Keywords: Polarography ; Square-wave voltammetry ; tert-Butylhydroquinone ; Emulsions ; Food ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An electroanalytical study of the oxidation of tert-butylhydroquinone (TBHQ) by differential pulse polarography (DPP) and square-wave voltammetry (SWV) in an emulsified medium formed with ethyl acetate and Pluronic F-68 is carried out. The optimization of the chemical variables of the emulsions by DPP allowed the choice of the following working conditions: pH 9.0, 0.04% Pluronic F-68, 2.0 mL of ethyl acetate and 3 minutes as ultrasonic stirring time. The demonstrated reversibility of the electrode process at the mercury electrode makes it suitable for the application of SWV. The influence of the square-wave (SW) characteristic parameters on the TBHQ net peak current at the hanging mercury drop electrode (HMDE) was tested. Calibration graphs were obtained within the ranges 1.0 × 10-5 to 1.0 × 10-4, 1.0 × 10-6 to 1.0 × 10-5, and 1.0 × 10-7 to 1.0 × 10-6 mol L-1. An improved sensitivity with respect to that obtained by DPP was produced. The limit of detection was found to be 6.2 × 10-8 mol L-1. Interferences from tert-butylhydroxyanisole, tert-butylhydroxytoluene, propylene glycol, citric acid, propyl gallate, and ascorbic acid were tested. The proposed method was applied with good results to the determination of TBHQ in spiked popcorn samples by direct emulsification of the ethyl acetate sample extract.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elan.1140061116
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  • 5
    Electronic Resource
    Electronic Resource
    Development of an amperometric enzyme biosensor for the determination of the antioxidant tert-butylhydroxyanisole in a medium of reversed micelles (1996)
    Weinheim : Wiley-Blackwell
    Electroanalysis 8 (1996), S. 529-533 
    Details
    ISSN: 1040-0397
    Keywords: Tyrosinase electrode ; Reversed micelles ; Flow injection ; Phenolic antioxidants ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A biocdtalytic scheme, based on the enzyme tyrosinase, has been developed for the determination of the antioxidant tert-butylhydroxyanisole (BHA) in food samples. Reversed micelles formed with ethyl acetate as organic solvent, dioctyl sulfosuccinate (AOT) as emulsifying agent, and phosphate buffer of pH 7.4 as aqueous phase, has been employed as the working medium. The potential applied to the tyrosinase electrode, as well as the temperature of the working reversed micelle, the percentage of aqueous phase, and the pH of the phosphate buffer solution have been optimized. The stability of the enzyme electrode with time has been also evaluated. A very good selectivity has been found with respect to potential interference from other substances commonly present in commercial antioxidant mixtures in food. An Eastman-AQ/enzyme immobilization approach has been employed to improve the stability of the tyrosinase biosensor in reversed micelles flowing streams. A flow injection method with amperometric detection for the determination of BHA has been developed and applied to the analysis of this antioxidant in commercial biscuits.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elan.1140080606
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