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  • 1
    ISSN: 1573-5044
    Keywords: Mucuna pruriens ; entrapped plant cells ; bioconversions ; catechols ; isolation ; mass spectrometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Alginate-entrapped cells ofM. pruriens were able to convert a number of parasubstituted monophenolic compounds into the corresponding catechols. All catechols produced were released into the medium, which offered the opportunity to isolate these products via a relatively simple procedure. Prepurification was performed on a Sephadex G10 gel and catechols were concentrated on Affigel 601. The identity of all products was confirmed with combined liquid chromatography/mass spectrometry (LC/MS) or MS using the desorption chemical ionization technique, depending on the catechol. For the entrapped cells and for a cell homogenate prepared of the same cell line ofM. pruriens the substrate specificities were qualitatively identical when judged on initial rates of synthesis calculated on protein basis.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1573-5044
    Keywords: 3-aminotetralins ; bioconversions ; catechols ; entrapped plant cells ; mass spectrometry ; Mucuna pruriens L.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Although alginate-entrapped cells of Mucuna pruriens L. possess a low substrate specificity, only para-substituted monocyclic phenols have been ortho-hydroxylated into catechols so far. In this study, compounds with more complex chemical structures were found to be substrates using entrapped cells of M. pruriens as well as the partially purified Mucuna-phenoloxidase. Thus, 5-, 6- and 7-hydroxylated 2-aminotetralins and a tricyclic compound, 9-hydroxy N-n-propyl hexahydronaphthoxazine, were converted into catechols. After isolation using preparative HPLC, the identity of the products was confirmed by MS. In general, for the entrapped cells and the enzyme preparation identical substrate specificities were found.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1573-5044
    Keywords: coniferin ; lignan biosynthesis ; permeabilization ; phenylpropanoid precursors ; podophyllotoxin ; Podophyllum hexandrum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In order to improve the production of the cytotoxic lignan podophyllotoxin, seven precursors from the phenylpropanoid-routing and one related compound were fed to cell suspension cultures derived from the rhizomes of Podophyllum hexandrum Royle. These cell cultures were able to convert only coniferin into podophyllotoxin, maximally a 12.8 fold increase in content was found. Permeabilization using isopropanol, in combination with coniferin as a substrate, did not result in an extra increase in podophyllotoxin accumulation. Concentrations of isopropanol exceeding 0.5% (v/v) were found to be rather toxic for suspension growth cells of P. hexandrum. When coniferin was fed in presence of such isopropanol concentrations, β-glucosidase activity was still present, resulting in the formation of the aglucon coniferyl alcohol. In addition, podophyllotoxin was released into the medium under these permeabilization conditions. Entrapment of P. hexandrum cells in calcium-alginate as such or in combination with the feeding of biosynthetic precursors, did not improve the podophyllotoxin production. Cell-free medium from suspension cultures at later growth stages incubated with coniferin, resulted in the synthesis of the lignan pinoresinol.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Plant cell, tissue and organ culture 20 (1990), S. 81-87 
    ISSN: 1573-5044
    Keywords: anti-tumour activity ; elicitation ; lignan biosynthesis ; 5-methoxypodophyllotoxin ; phenylalanine ammonia lyase ; phenylpropanoid pathway
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Cell suspension cultures of Linum flavum L., routinely grown on a NAA-containing medium, accumulated low levels of the phenylpropanoid-derived lignan 5-methoxypodophyllotoxin (5-MPT), up to 0.004% on a dry weight basis. Feeding experiments with the precursor L-phenylalanine resulted in a 3–5-fold increase in 5-MPT levels, but caused the levels of PAL activity to fall. Treatment of the cultures with the elicitor Nigeran, either alone or in combination with phenylalanine, caused the 5-MPT production to cease, even though PAL activity was rapidly enhanced by these treatments. Transfer of the cultures to NAA-free medium resulted in a 40–50 fold higher level of 5-MPT accumulation, the PAL activity levels being lowered compared to the routinely grown cells. With these more differentiated cultures, phenylalanine feeding and elicitor treatment, both on its own and in combination with the precursor, had no effect on 5-MPT production, even though the PAL activity levels were higher than in the untreated cells. It can be concluded that in lignan-accumulating cultures of L. flavum, PAL activity is nearly always detectable and seems to show a reciprocal relationship with 5-MPT accumulation.
    Type of Medium: Electronic Resource
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