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1990 (1)
1981 (1)
1Author    Dieter StrackRequires cookie*
 Title    Sinapine as a Supply of Choline for the Biosynthesis of Phosphatidylcholine in Raphanus sativus Seedlings  
 Abstract    Biosynthesis o f phosphatidylcholine in young seedlings o f Raphanus sativus is supplied with choline from degradation of the seed constituent sinapine (sinapoylcholine). This conclusion has been deduced from the following results: (1) Raphanus sativus seedlings accumulate approx. 70 nmol phosphatidylcholine which may be relevant for the consumption of choline, liberated during hydrolysis of approx. 130 nmol sinapine. (2) [14C]choline and [14C]ethanolamine, taken up by germinating Raphanus seeds, are exclu­ sively consumed in the biosynthesis o f phosphatidylcholine and phosphatidylethanolamine, respectively. (3) Pulse-chase experiments with seedlings at different germination stages show a reduced [14C]choline incorporation into phosphatidylcholine at the time when degradation o f sinapine occurs, obviously as a result of an isotope dilution by an increase o f the endogenous choline pool. (4) After [14C]choline pulse to immature seeds, during the process o f seed maturation most of the activity taken up is incorporated into accumulating sinapine and approx. 50% compared to this into phosphatidylcholine. During seedling development the quantity o f labelled sinapine rapidly decreases as a result of sinapine degradation with a concomitant label increase in free choline, phosphorylcholine, and phosphatidylcholine. Approx. 50% of the choline liberated from sinapine, is consumed in the biosynthesis of phosphatidylcholine. High performance liquid chromatographic analyses of phosphatidylcholine during Raphanus germination revealed that this phospholipid might be a metabolically active compound. Changes in the absorptivity of this compound at 210 nm indicate changes in the degree of unsaturation in the fatty acyl groups. 
  Reference    Z. Naturforsch. 36c, 215—221 (1981); received December 231980 
  Published    1981 
  Keywords    Sinapine, Phosphatidylcholine, Phenylpropanoids, Phospholipids, Raphanus, Brassicaceae 
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 TEI-XML for    default:Reihe_C/36/ZNC-1981-36c-0215.pdf 
 Identifier    ZNC-1981-36c-0215 
 Volume    36 
2Author    Petra Sperling, Ute Hammer, Wolfgang Friedt, Ernst HeinzRequires cookie*
 Title    High Oleic Sunflower: Studies on Composition and Desaturation of Acyl Groups in Different Lipids and Organs  
 Abstract    A selection o f lipids from achenes, cotyledons after germination, roots and leaves o f normal and high oleic varieties o f sunflower were analyzed with regard to their fatty acid profiles. The lipids included triacylglycerol and phosphatidylcholine as ER-made components and mono-and digalactosyl diacylglycerol as plastid-localized glycolipids. A comparison o f fatty acid pat­ terns showed that the block in oleate desaturation o f the high oleic variety is confined to the ER o f fat accumulating embryos, but that upon germination the oleate desaturation in the cotyledonary ER is rapidly derepressed. These data are supported by enzymatic experiments. In m icrosomes from maturing fruits o f the high oleic variety oleoyl-phosphatidylcholine de-saturase could not be detected, whereas o leo y l-C o A : lyso-phosphatidylcholine acyltransferase and com ponents o f the microsomal electron transport chains were not affected. A correlation in the expression o f desaturation blocks in seed and root fatty acids as observed in mutants o f other species was not observed which, therefore, cannot be generalized. Our data are discussed in terms o f the existence o f two ER-specific oleate desaturase activities. 
  Reference    Z. Naturforsch. 45c, 166 (1990); received November 20 1989 
  Published    1990 
  Keywords    Triacylglycerols, G alactolipids, Phosphatidylcholine, Cotyledons, Leaves, Roots 
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 TEI-XML for    default:Reihe_C/45/ZNC-1990-45c-0166.pdf 
 Identifier    ZNC-1990-45c-0166 
 Volume    45