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1992 (1)
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1Author    M. Wink, T. Hartmann, L. WitteRequires cookie*
 Title    Enzymatic Synthesis of Quinolizidine Alkaloids in Lupin Chloroplasts  
 Abstract    The enzymatic sequence responsible for the biosynthesis o f tetracyclic quinolizidine alkaloids could be localized in chloroplasts isolated from Lupinus polyphyllus leaves and L. albus seedlings by differential centrifugation. U pon feeding of cadaverine to isolated chloroplasts lupanine is produced as the m ain alkaloid. Chloroplasts treated with digitonine produce sparteine and 17-oxosparteine instead o f lupanine, thus indicating that the biosynthetic sequence is interrupted. The intermediacy of 17-oxosparteine could be confirmed since exogeneous 17-oxosparteine is con­ verted into lupanine by intact chloroplasts. 17-Oxosparteine synthase (see Z. N aturforsch. 34 c, 704 1979) the key enzyme of quinolizidine alkaloid biosynthesis could be solubilized from chloro­ plasts treated with detergents or osmotic shock. 
  Reference    Z. Naturforsch. 35c, 93—9 (1980); received Septem ber 26 1979 
  Published    1980 
  Keywords    Quinolizidine Alkaloids, Enzymatic Synthesis, Isolated Chloroplasts, Lupinus polyphyllus 
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 TEI-XML for    default:Reihe_C/35/ZNC-1980-35c-0093.pdf 
 Identifier    ZNC-1980-35c-0093 
 Volume    35 
2Author    Andrea Feld, Klaus Kobek, HartmutK. LichtenthalerRequires cookie*
 Title    Inhibition of de novo Fatty-Acid Biosynthesis in Isolated Chloroplasts by Different Antibiotics and Herbicides  
 Abstract    Two natural antibiotics, cerulenin and thiolactomycin, were tested for their inhibitory efficacy on de novo fatty-acid biosynthesis of chloroplasts isolated from oat and spinach seedlings and compared with that of known herbicides. With both antibiotics a strong dose-dependent inhibition of the incorporation of [l-14C]acetate into the fatty-acid fraction of the isolated plastids was detected. The /50-values for the inhibition of acetate incorporation into fatty acids are about 4 fiM in the case of thiolactomycin and about 50 ^im in the case of cerulenin for both mono-and dicotyledonous plants. These values are much higher than those of the particular graminicides cycloxydim and diclofop (0.15 and 0.1 ^im), which were developed to control grass weeds in dicotyledonous crop cultures. 
  Reference    Z. Naturforsch. 44c, 976 (1989); received July 3 1989 
  Published    1989 
  Keywords    Cerulenin, de novo Fatty-Acid Biosynthesis, Isolated Chloroplasts, Thiolactomycin 
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 TEI-XML for    default:Reihe_C/44/ZNC-1989-44c-0976.pdf 
 Identifier    ZNC-1989-44c-0976 
 Volume    44 
3Author    Bernd Listab, A.Ndrea Golza, Wilhelm Bolandb, H. Artm, K. Lichtenthaler3Requires cookie*
 Title    Inhibition of de novo Fatty-Acid Biosynthesis in Isolated Chloroplasts by the Antibiotic Cerulenin and Its Synthetic Derivatives  
 Abstract    The antibiotic cerulenin was shown to be a potent dose-dependent inhibitor o f de novo fatty-acid biosynthesis in intact isolated chloroplasts o f different plants (measured as [l4C]acetate incorporation into the total fatty-acid fraction). Various chemical derivatives o f cerulenin were synthesized and tested in the chloroplast assay-system o f oat, spinach and pea. M odifica­ tions o f the hydrocarbon chain o f cerulenin (e.g. tetrahydro-cerulenin and its short-chain c«-2,3-epoxy-4-oxoheptanam ide derivative) decreased the inhibitory activity o f cerulenin, whereas variations o f the epoxy-oxo-am ide structural element led to a com plete loss o f inhibi­ tion potency. The results indicate that the naturally occurring antibiotic cerulenin is the most active specific inhibitor o f de novo fatty-acid biosynthesis, but the form ation o f the hydroxy-lactam ring seems to be an essential requirement for the inhibitory activity. Those structural analogues o f cerulenin, which can no longer form a hydroxylactam ring, do not possess any inhibitory capacity. 
  Reference    Z. Naturforsch. 47c, 382 (1992); received March 10 1992 
  Published    1992 
  Keywords    Cerulenin, Cerulenin Derivatives, de novo Fatty Acid Biosynthesis, Isolated Chloroplasts 
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 TEI-XML for    default:Reihe_C/47/ZNC-1992-47c-0382.pdf 
 Identifier    ZNC-1992-47c-0382 
 Volume    47