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  • 1
    Electronic Resource
    Electronic Resource
    A method for long-term micropropagation of Phaseolus coccineus L. (1993)
    Springer
    Plant cell reports 12 (1993), S. 395-398 
    Details
    ISSN: 1432-203X
    Keywords: Phaseolus cocdneus ; Plant regeneration ; Chromosome number ; Isozymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A method for long-term plant regeneration of Phaseolus coccineus L, is described. Shoot-tips and cotyledonary nodes cultured on a Murashige and Skoog medium supplemented with N6-benzylaminopurine, 10 μM, and α-naphthaleneacetic acid, 1μM, formed multiple bud-shoots. These shoots were transferred to medium containing BAP 1 μM, NAA 0.1 μM, and gibberellic acid 3 μM to promote shoot growth and further shoot multiplication. Rooting was achieved in medium with 11 μM indole-3-acetic acid. Rooted plants grew to maturity and were fertile. Cultures have maintained their ability to regenerate plants for more than two years. A sample of 30 regenerated plants (R0) was tested for chromosome number, all of them being diploid; seven isozymatic systems were electrophpretically analyzed in 82 R0 regenerated plants. No differences were observed in their electrophoretic patterns in comparison with those shown by seedlings. Histological studies revealed the origin of buds from calluses via organogenesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234699
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  • 2
    Electronic Resource
    Electronic Resource
    Colchicine effect on the chromosome number of barley embryos culturedin vitro (1982)
    Springer
    Protoplasma 113 (1982), S. 237-240 
    Details
    ISSN: 1615-6102
    Keywords: Aneuploidy ; Barley ; Chromosome number ; Colchicine ; “In vitro” culture ; Polyploidy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The effect of colchicine upon the embryos of barley (Hordeum vulgare L.) culturedin vitro has been studied. Different concentrations of the drug as well as different times of culture in its presence have been tested, in order to ascertain the optimal conditions for the induction of non diploid cells. Tetraploid cells were always infrequent after the treatments, reaching the higher values during the first days of culture; aneuploid cells being frequent in some cases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01280913
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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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