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1985 (1)
1980 (1)
1Author    M. Wink, L. WitteRequires cookie*
 Title    Quinolizidine Alkaloids as Nitrogen Source for Lupin Seedlings and Cell Cultures  
 Abstract    The alkaloid patterns during germination and seedling development of Lupinus polyphyllus, L. angustifolius, L. albus, L. pubescens, Cytisus scoparius, Baptisia australis, Spartium junceum and Laburnum anagyroides were studied by capillary glc and EI-MS and CI-MS. The alkaloid contents were relatively high in the seeds and decreased by 20—100% during germination and the early developmental stages. The plants with fully developed leaves were able to synthesize new alkaloids. The decrease of alkaloid concentrations during germination was interpreted in terms of alkaloid turnover and use of the alkaloidal nitrogen for seedling development. The ability of plants to rely on the alkaloidal nitrogen as a nitrogen source could also be shown in lupin cell cultures which could survive and even grow on media which contained sparteine as the sole nitrogen source. 
  Reference    Z. Naturforsch. 40c, 767—775 (1985); received August 19/September 4 1985 
  Published    1985 
  Keywords    Alkaloid Turnover, Quinolizidine Alkaloids, Lupinus, Germination, Nitrogen Source 
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 TEI-XML for    default:Reihe_C/40/ZNC-1985-40c-0767.pdf 
 Identifier    ZNC-1985-40c-0767 
 Volume    40 
2Author    Eckhard BastRequires cookie*
 Title    Ammonia Assimilation by Thiocapsa roseopersicina Grown on Various Nitrogen and Carbon/Electron Sources  
 Abstract    Batch cultures o f the phototrophic bacterium, Thiocapsa roseopersicina, were grown anaero­ bically in the light either on sulfide with various ammonia concentrations, N 2 or amino acids as nitrogen sources, or on several simple organic substrates in the absence o f reduced sulfur com­ pounds using 6 mM N H 4C1 as source o f nitrogen. At high ammonia concentrations high activities of (NADPH-linked) glutamate dehydrogenase (GDH), but rather low transferase and no bio­ synthetic activity of glutamine synthetase (GS) were obtained, while under conditions o f ammonia deficiency (growth with N 2 or glutamate) GDH activity was very low and both GS activities were strongly increased. Glutamate synthase (GOGAT) activity (NADH-dependent) showed little variation. These data indicate that at high NH+ concentrations ammonia is assimilated via GDH, under NHJ limitation, however, via the G S/G O G A T system. Glutamine as nitrogen source may be utilized via GOGAT as well as via an active glutaminase plus GDH. Ammonia, but not glutamine, seems to cause repression and inactivation of GS. Alanine and asparagine inactivate the enzyme inhibiting the biosynthetic, but not the transferase activity. These amino acids in part also influence the activities o f GDH, GOGAT, malate dehydrogenase (MDH) and isocitrate dehydro­ genase (ICDH). Cultures grown on acetate or pyruvate instead of sulfide showed increased GDH activities and high GS transferase activities possibly reflecting an increase o f intracellular a-ketoglutarate con­ centration. On malate or fructose also increased GS transferase activities, but rather low GDH activities were observed. High biosynthetic GS activities and elevated GOGAT activities were found only in fructose-grown cells. On the organic substrates the ICDH activities always were somewhat higher than after lithoautotrophic growth. With the exception of acetate, the MDH activities were considerably elevated, especially on pyruvate. The different pathways of ar-keto-glutarate formation and their influence on the enzymes of ammonia assimilation are discussed. 
  Reference    Z. Naturforsch. 35c, 439 (1980); received December 17 1979 
  Published    1980 
  Keywords    Thiocapsa roseopersicina, Phototrophic Bacteria, Nitrogen Sources, Ammonia Assimilation, Carbon Metabolism 
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 TEI-XML for    default:Reihe_C/35/ZNC-1980-35c-0439.pdf 
 Identifier    ZNC-1980-35c-0439 
 Volume    35