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'Daucus carota' in keywords
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1983 (1)
1979 (3)
1Author    BenjaminF. Matthews, JackM W IdholmRequires cookie*
 Title    Expression of Aspartokinase, Dihydrodipicolinic Acid Synthase and Homoserine Dehydrogenase During Growth of Carrot Cell Suspension Cultures on Lysine-and Threonine-Supplemented Media  
 Abstract    Reduction in the amounts o f activity o f the first enzyme, aspartokinase (EC 2.7.2.4) and two branch-point enzymes, dihydrodipicolinic acid synthase (EC 4.2.1.52) and homoserine dehydrogen­ ase (EC 1.1.1.3), located in the pathway for the synthesis o f aspartate-fam ily am ino acids, oc­ curred when cell suspension cultures of Daucus carota L. var. Danvers were grown in media contain­ ing 2 m M threonine or 2 m M lysine, endproducts of the pathway. Activity o f the lysine-sensitive form of aspartokinase was decreased when cells were grown in medium containing lysine and the ac­ tivity of the threonine-sensitive form was decreased when cells were grown in m edium containing threonine. Activity o f the branch-point enzyme leading to threonine synthesis, hom oserine dehy­ drogenase, was decreased up to 70% in specific activity (units/m g protein) and relative activity (units/g fresh weight) when cells were grown in m edia containing lysine or threonine. Threonine had no effect on the relative activity of dihydrodipicolinic acid synthase, but decreased its specific activity. Lysine decreased the relative activity of the synthase by up to 40%, but had little effect on its specific activity. The decreased activities o f the enzymes were apparently not due to binding of the inhibitory amino acids to the enzymes since homogenization of cells in buffer with 2 m M lysi­ ne and threonine did not decrease the m easurable enzyme activities. These and other results pres­ ented suggest that both forms of the aspartokinase activity and homoserine dehydrogenase activi­ ty can be altered by supplementing the growth medium with lysine or threonine. 
  Reference    Z. Naturforsch. 34c, 1177—1185 (1979); received June 18 1979 
  Published    1979 
  Keywords    Daucus carota, Suspension Cultures, Amino Acids, Enzyme Regulation 
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 TEI-XML for    default:Reihe_C/34/ZNC-1979-34c-1177.pdf 
 Identifier    ZNC-1979-34c-1177 
 Volume    34 
2Author    Ursula Seitz, Ulrich SeitzRequires cookie*
 Title    The Molecular Weight of rRNA Precursor Molecules and Their Processing in Higher Plant Cells  
 Abstract    Actively dividing callus cells of higher plants (Petroselinum crispum, Daucus carota, Acer pseudoplatanus) were used to detect the primary gene product of rDNA in vivo. Parsley and carrot cells were labelled with [32P] orthophosphate. Under non-denaturing conditions, in both cases only one high molecular weight rRNA precursor was present on polyacrylamide gels. Its molecular weight did not exceed 2.5X10® dalton. Under denaturing conditions, 2.0 — 2.1X10® dalton were determined on formamide gels. This rRNA precursor was already present after a labelling period of 5 —10 min. In parsley cells labelled mature rRNA (25S and 18S) arrived in the cytoplasm 45 min after onset of incubation. In Acer pseudoplatanus incubated with [3H] uridine two rapidly labelled components did emerge from polyacrylamide gels without formamide; their molecular weights were 2.3 and 3.2 — 3.4X10® dalton. After electrophoresis in formamide, the larger component disappeared, thus indicating that it would be an intermolecular aggregate of different for the existence of rRNA precursors exceeding the 
  Reference    Z. Naturforsch. 34c, 253 (1979); received January 23 1979 
  Published    1979 
  Keywords    Petroselinum crispum, Daucus carota, Acer pseudoplatanus, Callus Cells, rRNA Precursor 
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 TEI-XML for    default:Reihe_C/34/ZNC-1979-34c-0253.pdf 
 Identifier    ZNC-1979-34c-0253 
 Volume    34 
3Author    Florenz Sasse, Dietlinde Backs-Hüsemann, Wolfgang BarzRequires cookie*
 Title    Isolation and Characterization of Vacuoles from Cell Suspension Cultures of Daucus carota  
 Abstract    A reliable procedure for the isolation o f vacuoles from anthocyanin-containing cells o f Daucus carota cell suspension cultures has been developed. From cells o f the late linear growth phase, protoplasts were prepared and purified in a sucrose/sorbitol gradient. Vacuoles were liberated from these protoplasts by osm otic shock and purified in a M etrizamide step gradient. The vacuole-containing fractions were analysed for their anthocyanin content as a measure for the yield o f vac­ uoles. The purity o f vacuoles was examined by assaying various marker enzym es in both proto­ plasts and vacuoles. The purest vacuolar fraction had 8% o f the total activity o f glucose-6-phos-phate dehydrogenase (marker for cytosol), 8% o f cytochrom e oxidase (m itochondria) and 10% o f N A DPH -cytochrom e c reductase (ER). 55% o f the acid phosphatase activity o f the protoplasts and 35% o f the total malate were recovered in the vacuoles. The vacuolar pool o f am ino acids is quite large. D ata for 15 am ino acids show that 44 to 73% are being located in the vacuole. 
  Reference    Z. Naturforsch. 34c, 848—853 (1979); received M ay 15 1979 
  Published    1979 
  Keywords    Daucus carota, Protoplasts, Vacuoles, Lysosomes, A m ino Acids, Anthocyanin 
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 TEI-XML for    default:Reihe_C/34/ZNC-1979-34c-0848.pdf 
 Identifier    ZNC-1979-34c-0848 
 Volume    34 
4Author    W. N. Oé, H. U. SeitzRequires cookie*
 Title    Studies on the Regulatory Role of fra/is-Cinnamic Acid on the Activity of the Phenylalanine Ammonia-Lyase (PAL) in Suspension Cultures of Daucus carota L  
 Abstract    In vivo and in vitro experiments were performed in order to study the regulatory role of trans-cinnamic acid and its hydroxylated derivatives (p-coumaric acid, caffeic acid) on the deamina­ tion of phenylalanine catalyzed by PAL (EC 4.3.1.5). 7>arts-cinnamic acid inhibits growth and reduces the content of soluble proteins of anthocyanin-containing carrot cells grown in suspen­ sion. There is strong evidence from the polysomal patterns and from the effect of ?ra«5-cinnamic acid on protein synthesis in vitro that protein synthesis is inhibited. The kinetic data of PAL clearly demonstrate that /ra«s-cinnamic acid inhibits the enzyme by a noncompetitive mecha­ nism. On the contrary, L-a-aminooxy-/?-phenylpropionic acid (l-AOPP), a competitive inhibitor of PAL, does not affect protein metabolism. 
  Reference    Z. Naturforsch. 38c, 408 (1983); received January 24 1983 
  Published    1983 
  Keywords    Phenylalanine Ammonia-Lyase, Protein Metabolism, Regulation, /ra/js-Cinnamic Acid, Daucus carota, Suspension Culture 
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 TEI-XML for    default:Reihe_C/38/ZNC-1983-38c-0408.pdf 
 Identifier    ZNC-1983-38c-0408 
 Volume    38