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1994 (1)
1993 (1)
1Author    WieslawI. Gruszecki, ZbigniewK. RupaRequires cookie*
 Title    Changes of Excitation Spectra of in vivo Chlorophyll Fluorescence during Induction of Photosynthesis  
 Abstract    Excitation spectra of chlorophyll fluorescence from intact rye leaves were registered at dif­ ferent steps of the induction of photosynthesis after dark adaptation. Analysis of these spectra indicates that at least two processes related to spectroscopic features are responsible for a flu­ orescence quenching. The first one, active during the first 100 s of illumination, was interpret­ ed to consists in an overall decrease of the fluorescence quantum yield of antenna pigments and chlorophylls, in particular close to the reaction centers. The second type of a fluorescence decrease (between 100 s and 300 s o f illumination) was found to be in large extent related to decrease of the rate of an excitation energy transfer between accessory xanthophyll pigments and chlorophylls emitting fluorescence. This latter molecular mechanism is discussed as being related to violaxanthin availability to de-epoxidation in the xanthophyll cycle. 
  Reference    Z. Naturforsch. 48c, 46—51 (1993); received September 21/December 31 1992 
  Published    1993 
  Keywords    Chlorophyll Fluorescence, Photosynthesis, Violaxanthin, Xanthophyll Cycle 
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 TEI-XML for    default:Reihe_C/48/ZNC-1993-48c-0046.pdf 
 Identifier    ZNC-1993-48c-0046 
 Volume    48 
2Author    A. M. Akewicz, A. R. Adunz, G. H. SchmidRequires cookie*
 Title    Immunological Evidence for the Binding of ß-Carotene and Xanthophylls onto Peptides of Photosystem I from Nicotiana tabacum  
 Abstract    Photosystem I preparations were obtained from wild type tobacco Nicotiana tabacum var. John William's Broadleaf (JWB) and from the two chlorophyll-deficient mutants N tabacum Su/su and N. tabacum Su/su var. Aurea. The preparations were characterized with respect to the chlorophyll a/b ratio, their photosynthetic activity and their absorption spectroscopic properties. Peptides from these preparations were analyzed by SDS polyacrylamide gel elec­ trophoresis and transferred for the detection of bound carotenoids according to the Western blot procedure to nitrocellulose or Immobilon membranes. The PS I preparation from the wild type JW B consisted of the core and the LH CP complex. The core complex contains the two core peptides with the same apparent MW of 6 6 kD a and several peptides with the lesser molecular masses of 22, 20, 19, 17, 16, 10 and 9 kDa. The light-harvesting protein complex consists of 4 subunits with the molecular masses 28, 26, 25 and 24 kDa. The PS I preparations of the yellow-green mutant Su/su and of the A urea mutant Su/su var. Aurea contain as impurity traces of the Dl and D 2 core peptides of photosystem II and also traces of the chlorophyll-binding photosystem II peptides with the molecular masses 42 and 47 kDa. The peptides of the photosystem I preparation were characterized by specific photosys­ tem I antisera: An antiserum to the photosystem I complex reacts in the Western blot only with the homologous peptides of photosystem I. In comparative analyses with photosystem II preparations this antiserum (directed to photosystem I) reacts, as expected, only with the peptides of the light-harvesting complex. An antiserum to the C P I core peptides reacts only with the 6 6 kD a peptides of photosystem I and gives no cross reaction with heterodimer forms of the D !/D 2 core peptides of photosystem II. In the Western blot procedure by means of polyclonal monospecific antisera to carotenoids it was dem onstrated that ß-carotene is bound in high concentration onto the core peptides CPI and to a lesser extent onto the two larger subunits of the LHCP complex, exhibiting the molecular masses of 28 and 26 kDa. N eoxanthin is bound onto the same peptides. In contrast to this, lutein was only identified on the core peptides C P I and violaxanthin only on the larger subunits of the LH CP complex. As the carotenoids are labelled with antibodies, even after SDS treatm ent in the electrophoresis, it is assumed, that the carotenoids are co­ valently bound via the ionon ring to the respective peptide. 
  Reference    Z. Naturforsch. 49c, 427—438 (1994); received February 17 1994 
  Published    1994 
  Keywords    Photosystem I, ß-Carotene, Lutein, Violaxanthin, Neoxanthin, Antibodies 
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 TEI-XML for    default:Reihe_C/49/ZNC-1994-49c-0427.pdf 
 Identifier    ZNC-1994-49c-0427 
 Volume    49