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1988 (1)
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1Author    Fabrice Franck, GeorgH. SchmidRequires cookie*
 Title    The Role of N ADPH in the Reversible Phototransformation of Chlorophyllide P682 into Chlorophyllide P678 in Etioplasts of Oat  
 Abstract    Absorption spectra and room temperature fluorescence variations upon light excitation were studied in etioplasts in which the protochlorophyllide had been reduced to chlorophyllide prior to the experiment. In the presence of 1 mM NADPH, the absorption band was located around 682 nm and the fluorescence variations reflected the occurrence of the chlorophyllide microcycle (reversible phototransformation of chlorophyllide P682 into chlorophyllide P678). whereas, in the absence of NADPH, the absorption band was located around 676 nm and the fluorescence exhibited only a slow decrease with illumination time. After washing, NADPH-treated etioplasts still exhibited an absorption maximum of 682 nm, which shifted irreversibly to 678 nm upon illumination. Re-addition of only 10 |im NADPH restored the reversibility of the reaction. Plas­ tids were also prepared after a brief illumination of the intact leaves. These plastids contained the P682 chlorophyllide. In this preparation, essentially the same phenomena were observed as in NADPH-treated etioplasts after washing. Moreover, enzymic oxidation of NADPH resulted in the transformation of P682 into P678 in darkness. Addition of the Hill electron acceptors 2,6-dimethylbenzoquinone on FeCN caused an acceleration of the phototransformation of P682 into P678. We interpret these results as being due to the oxidation of NADPH during the phototrans­ formation of P682 into P678. The nature of the electron acceptor and the physiological role of this reaction is discussed. 
  Reference    Z. Naturforsch. 40c, 832—838 (1985); received September 13 1985 
  Published    1985 
  Keywords    Etioplasts, Chlorophyllide, NADPH 
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 TEI-XML for    default:Reihe_C/40/ZNC-1985-40c-0832.pdf 
 Identifier    ZNC-1985-40c-0832 
 Volume    40 
2Author    Cornelius LützRequires cookie*
 Title    The Determ ination o f Prolam ellar Bodies and Saponins in E tioplasts and Leaves o f A vena sativa L  
 Abstract    Prolamellar body tubules in etioplasts are composed mainly of two saponins. The determination o f these sapo-nins in leaves, etioplasts or subfractions of etioplasts is re­ commended to evaluate the concentration of these tubules in a given fraction. Using a densitometer after TLC-separa-tion of the saponins measurements are carried out in a short time with high accurancy. Also the absolute concen­ tration of these saponins can be determined. Problems in the quantification o f the saponins in leaf samples can be overcame with filters of different wavelengths. 
  Reference    Z. Naturforsch. 35c, 519—521 (1980); received January 21 1980 
  Published    1980 
  Keywords    Etioplasts, Prolamellar Bodies, Saponins, Chromatography 
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 TEI-XML for    default:Reihe_C/35/ZNC-1980-35c-0519_n.pdf 
 Identifier    ZNC-1980-35c-0519_n 
 Volume    35 
3Author    Fabrice Franck, GeorgH. SchmidRequires cookie*
 Title    Flash Pattern of Oxygen Evolution in Greening Etioplasts of Oat  
 Abstract    Etioplasts isolated from oat leaves that have received two 5 m in illum ination periods, spaced apart by a 90 min dark interval, are able to evolve oxygen. If this oxygen evolution is measured as consequence o f short saturating light flashes a pattern is obtained w hich in agreem ent with the Kok-Joliot model shows a dam ped oscillation w ith a periodicity o f four. As usual for most other systems the maximum flash yield is observed under the third flash. In continuous light such slightly greened etioplasts show a small oxygen gush. From our studies it appears that the second 5 min illumination period is obligatory for oxygen evolution. O m ission o f this period leads to a condition in which under flashes strictly no oxygen is evolved. In continuous light under these conditions no oxygen gush but rather an uptake is observed after onset o f illum ination. It appears that in greening etioplasts the flash pattern shows som e peculiarities when compared to the normal green conditions. Thus, a flash sequence o f a greening etioplast always shows a substantial positive amperometric signal under the first flash. The h alf tim e o f the state which would belong to this signal is 3 to 4 min in a greening etioplast, isolated from leaves that have received 2 h light. In the course o f greening this h alf tim e decreases continuously and reaches a normal and constant value o f approx. 1 0 s in chloroplasts from green oat or etiochloroplasts that are prepared from leaves that have received 15 h o f light. The result is discussed in terms o f metastable S3 which seems to be a property o f the developing oxygen evolving system in greening oat leaves. In the greening system as we use it is shown for the first tim e that the photoenzym e protochlorophyllide chlorophyllide reductase is D C M U sensitive. 
  Reference    Z. Naturforsch. 39c, 1091 (1984); received August 17 1984 
  Published    1984 
  Keywords    Flash Yield, Oxygen, S-States, Etioplasts 
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 TEI-XML for    default:Reihe_C/39/ZNC-1984-39c-1091.pdf 
 Identifier    ZNC-1984-39c-1091 
 Volume    39 
4Author    Martine Bertrand, Barbara Bereza, Esther DujardinRequires cookie*
 Title    Evidence for Photoreduction of NADP + in a Suspension of Lysed Plastids from Etiolated Bean Leaves  
 Abstract    It has been investigated if photoreduction of NADP + (detected by absorption spectroscopy) may take place in lysed plastids within minutes of exposure to light. This process was made possible by removal of oxidants from the reaction mixture. Lysed plastids were suspended in a medium containing NADP + , catalase, glucose oxidase and glucose; exposure to light simultane-ously to addition of ferredoxin and ferredoxin-NADP + reductase, resulted in increased absorb-ance in the band around 340 nm, while addition of 3-phosphoglycerate resulted in the disappear-ance of this band. Ferredoxin and ferredoxin-NADP + reductase are only effective when photo-activation takes place before their addition to the medium. 
  Reference    Z. Naturforsch. 43c, 443—448 (1988); received January 25 1988 
  Published    1988 
  Keywords    NADPH, NADP + Photoreduction, Etioplasts, Absorbance Difference Spectra, Phaseolus vulgaris 
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 TEI-XML for    default:Reihe_C/43/ZNC-1988-43c-0443.pdf 
 Identifier    ZNC-1988-43c-0443 
 Volume    43