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1989 (1)
1976 (1)
1Author    D. Urbach, M. Suchanka, W. UrbachRequires cookie*
 Title    Effect of Substituted Pyridazinone Herbicides and of Difunone (EMD-IT 5914) on Carotenoid Biosynthesis in Green Algae  
 Abstract    The carotenoid biosynthesis of the green alga A n kistrodesm u s braunii is blocked if these cells are cultured in presence of sublethal doses of pyridazinone herbicides (San 9789, San 6706, BASF 44521) or of the herbicide difunone (EMD-IT 5914). The amount of colored carotenoids normally found in these algae is reduced drastically and the precursors phytoene and phytofluene are ac­ cumulated. Furthermore a decrease in the chlorophyll level occurs in the treated cells, but there is a stronger loss of chlorophyll a, resulting in a lowering of the chlorophyll a/b ratio with time. Concerning the activity of substituted pyridazinones leading to inhibition of carotenoid biosynthesis this effect can be related to the chemical structure of these compounds: a trifluoromethyl substitu­ tion of the phenyl ring an d a mono-or dimethyl substitution of the amine (San 9789, San 6706) or a methoxy group instead of the substituted amine (BASF 44521) are required both for this effect. Other pyridazinone derivatives with eith er a trifluoromethyl substitution of the phenyl ring (San 9774) or a dimethyl substitution of the amine (San 9785) or a methoxy group (BASF 13761) are without any effect on the pigment pattern of these algae. 
  Reference    (Z. Naturforsch. 31c, 652 [1976]; received July 28 1976) 
  Published    1976 
  Keywords    Herbicides, Pyridazinone, Difunone, Carotenoid Biosynthesis, Green Algae 
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 TEI-XML for    default:Reihe_C/31/ZNC-1976-31c-0652.pdf 
 Identifier    ZNC-1976-31c-0652 
 Volume    31 
2Author    Susanne Biedlingmaier, A.Hlert SchmidtRequires cookie*
 Title    Sulfate Transport in Normal and S-Deprived Chlorella fusca  
 Abstract    Sulfate uptake into the unicellular green alga Chlorella fusca Shihira et Krauss strain 211-8 b was described as a pH-, temperature-and energy-dependent process. Transport followed triphasic kinetics with /^-values of 1.3 x 10-5, 3.9 x 10-5 and 2.8 x 10 4 m. The Hill plot showed coeffi­ cients of 1.0 for each uptake isotherm. Sulfate uptake was substantially inhibited by chromate, selenate, sulfite, thiosulfate and tetrathionate. Cysteine and other mercaptides diminished sulfate transport, whereas methionine was not inhibitory. Uptake was sensitive towards inhibitors of photosynthesis and respiration and towards SH-group reagents. Sulfate uptake could be strongly enhanced by polyvalent cations, apparently via reduction of the surface potential. Sulfate uptake in S-deprived algae was markedly different from constitutive sulfate uptake. Time kinetics was not linear but showed an initial rapid phase. Uptake was neither multiphasic nor conformed to simple Michaelis-Menten kinetics. Sulfate uptake was hardly affected by pH and temperature in the suboptimal range. The Arrhenius plot was biphasic with a discontinuity at 38 °C. 
  Reference    Z. Naturforsch. 44c, 495 (1989); received December 30 1988 D edicated to 
  Published    1989 
  Keywords    Cation Stimulation, Chlorella fusca, Green Alga, Multiphasic Uptake, Sulfate Analogues, Sulfate Starvation 
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 TEI-XML for    default:Reihe_C/44/ZNC-1989-44c-0495.pdf 
 Identifier    ZNC-1989-44c-0495 
 Volume    44