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'Catharanthus roseus' in keywords Facet   section ZfN Section C  [X]
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1989 (1)
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1Author    Yüko Yamashita, Hiroshi AshiharaRequires cookie*
 Title    Characterization of Hexokinase and Fructokinase from Suspension-Cultured Catharanthus roseus Cells  
 Abstract    Two different hexose-phosphorylating enzymes, hexokinase and fructokinase, were partially purified from suspension-cultured Catharanthus roseus cells. One of the enzymes, hexokinase, catalyzed the phosphorylation of both glucose and fructose. The K m values for glucose and fructose were 0.06 mM and 0.23 mM, respectively. The V max of the enzyme with fructose was approximately three times higher than with glucose. This enzyme was specific in its requirement for ATP and its K m value for ATP was 52 (ÍM. The optimum pH was 8.0 and Mg :+ or Mn :+ was required for the activity. The activity was inhibited by considerably higher concentrations of ADP (i.e., 4 mM ADP was required for 50% inhibition). The second enzyme, fructokinase, was specific for fructose, and no activity was detected with glucose as substrate. This enzyme used UTP or CTP as phosphate donor. The K m values of this enzyme for fructose and UTP were 0.13 mM and 0.15 mM, respectively. The pH optimum was 7.2, and Mg 2+ or Mn 2+ was required for the activity. These divalent cations could be partially replaced by Ca 2+ . The activity was inhibited non-competitively by ADP and AMP. 90% inhibition of the activity by 0.5 mM ADP was observed in the presence of 2 mM UTP and 5 mM MgCl 2 . Fructose-2,6-bisphosphate, glucose-1,6-bisphos-phate, glucose-6-phosphate, and fructose-6-phosphate had little or no effect on the activity of both the hexokinase and the fructokinase. Based on these results, a discussion is presented of the role of hexokinase and fructokinase and their involvement in the regulation of the metabolism of sugars in Catharanthus cells. 
  Reference    Z. Naturforsch. 43c, 827—834 (1988); received June 28 1988 
  Published    1988 
  Keywords    Catharanthus roseus, Suspension Culture, Fructokinase, Glycolysis, Hexokinase 
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 TEI-XML for    default:Reihe_C/43/ZNC-1988-43c-0827.pdf 
 Identifier    ZNC-1988-43c-0827 
 Volume    43 
2Author    K.-H Knobloch, J. BerlinRequires cookie*
 Title    Influence of Medium Composition on the Formation of Secondary Compounds in Cell Suspension Cultures of Catharanthus roseus (L.) G. Don  
 Abstract    Cell suspension cultures o f Catharanthus roseus have been subjected to various m edia condi­ tions in order to stim ulate the formation o f indole alkaloids. H igh ajmalicine contents (up to 0.5 m g/g cell fresh weight) were achieved by transferring 2-week-old cell suspensions to a 10-fold volum e o f a 8% sucrose solution. The alkaloid accum ulation started two days after the transfer and reached a plateau after ten days. Furthermore an enhanced level o f phenolic com pounds was found, whereas growth o f the culture was low. The accumulation o f both, alkaloids and poly­ phenols was stimulated by high concentrations o f sucrose and low concentrations o f nitrogen con­ taining salts and phosphate. W hen these m inerals were added to the sucrose solution in con­ centrations com m only used for cell culture m edia, the accum ulation o f alkaloids and phenolic compounds was largely suppressed. 
  Reference    Z. Naturforsch. 35c, 551 (1980); received March 31 1980 
  Published    1980 
  Keywords    Catharanthus roseus, Cell Suspension Cultures, A lkaloids, Polyphenols, M edia Effects 
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 TEI-XML for    default:Reihe_C/35/ZNC-1980-35c-0551.pdf 
 Identifier    ZNC-1980-35c-0551 
 Volume    35 
3Author    K.-H Knobloch, B. Hansen, J. Berlin, ForschungM B H, A. Bteilung, Pflanzliche Zellkulturen, M. Ascheroder WegRequires cookie*
 Title    Medium-Induced Formation of Indole Alkaloids and Concomitant Changes of Interrelated Enzyme Activities in Cell Suspension Cultures of Catharanthus roseus  
 Abstract    Recently m edium conditions have been developed which stim ulate the form ation of the indole alkaloid ajm alicine in cell suspension cultures o f Catharanthus roseus [6]. W hen cells were subjected to these conditions the alkaloid accum ulation was preceded by a 12-fold increase o f the specific activity o f tryptophan decarboxylase. The enzyme activity showed a maxim um two days after the cell transfer into the induction medium and subsequently declined. In contrast the activity of strictosidine synthase, the enzyme condensing tryptam ine and secologanin, was present over the entire measuring period at a constant level. The intracellular content of tryp­ tamine and ajmalicine increased during a period of 6 days after cell transfer and reached a plateau after that time. A possible regulatory function o f tryptophan decarboxylase in indole alkaloid biosynthesis is discussed. 
  Reference    Z. Naturforsch. 36c, 40—4 (1981); received N ovem ber 3 1980 
  Published    1981 
  Keywords    Catharanthus roseus, Indole Alkaloids, Tryptophan Decarboxylase, Strictosidine Synthase, Media Effects 
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 TEI-XML for    default:Reihe_C/36/ZNC-1981-36c-0040.pdf 
 Identifier    ZNC-1981-36c-0040 
 Volume    36 
4Author    Kaoru Kubota, Xiao-Ni Li1, Hiroshi AshiharaRequires cookie*
 Title    The Short-Term Effects of Inorganic Phosphate on the Levels of Metabolites in Suspension-Cultured Catharanthus roseus Cells  
 Abstract    In order to analyze the effects o f inorganic phosphate (Pi) on the energy metabolism o f suspen­ sion-cultured cells o f Catharanthus roseus, short-term changes in levels o f glycolytic m etabolites were m onitored after the addition o f 1.25 mM Pi to cultures of cells previously cultured in a Pi-free M urashige-Skoog m edium for 24 h. The levels o f all phosphorylated interm ediates o f glycolysis exam ined were found to increase after addition o f Pi. The most striking increases were observed in levels o f glucose-6-phosphate and fructose-6-phosphate which rose to approximately 8 (after 30 min) and 15 tim es (after 120 min) their initial values. The levels o f A TP and pyrophosphate doubled during the first 30 min o f incubation. In contrast, the level of pyruvate decreased signifi­ cantly during the initial 30 min and then began to increase again for the next 90 min. The short­ term effects o f Pi on the rates o f synthesis o f proteins and R N A were estim ated from the rates o f incorporation o f 14C-labelled am ino acids and uridine into the macrom olecules. No appreciable stim ulation o f the synthesis o f proteins and R N A was induced by Pi within 120 min after the addition o f Pi. Possible m echanism s are discussed that may be involved in the changes in m etab o­ lism initiated by the addition o f Pi to the cultures. 
  Reference    Z. Naturforsch. 44c, 802—806 (1989); received June 5 1989 
  Published    1989 
  Keywords    Catharanthus roseus, Suspension Culture, Inorganic Phosphate, G lycolytic M etabolites, M etabolic Regulation 
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 TEI-XML for    default:Reihe_C/44/ZNC-1989-44c-0802.pdf 
 Identifier    ZNC-1989-44c-0802 
 Volume    44