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1Author    P. V. Sane, T. S. Desai, V. G. TatakeRequires cookie*
 Title    Luminescence from Photosystem I at High Temperatures  
 Abstract    The changes in the fluorescence and delayed fluorescence intensity of spinach leaf as affected by temperature were studied. It was observed that the delayed fluorescence showed a maximum at about 45 °C whereas the fluorescence maximum was at about 55 °C. An examination of the emission spectra of delayed fluorescence at different temperatures showed that at higher tem­ peratures the relative emission at 735 nm was increased. It is argued that at higher temperatures the luminescence from photosystem I contributes to delayed fluorescence. 
  Reference    Z. Naturforsch. 35c, 289—292 (1980); received November 1 1979 
  Published    1980 
  Keywords    Fluorescence, Delayed Fluorescence, Photosystem I 
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 TEI-XML for    default:Reihe_C/35/ZNC-1980-35c-0289.pdf 
 Identifier    ZNC-1980-35c-0289 
 Volume    35 
2Author    Michel Havaux3, Murielle EylettersbRequires cookie*
 Title    Is the in vivo Photosystem I Function Resistant to Photoinhibition? An Answer from Photoacoustic and Far-Red Absorbance Measurements in Intact Leaves  
 Abstract    Preillumination o f intact pea leaves with a strong blue-green light o f 400 W m "2 markedly inhibited both photoacoustically monitored 0 2-evolution activity and PS II photochemistry as estimated from chlorophyll fluorescence measurements. The aim o f the present work was to examine, with the help o f the photoacoustic technique, whether this high-light treatment dete­ riorated the in vivo PS I function too. High-frequency photoacoustic measurements indicated that photochemical conversion o f far-red light energy in PS I was preserved (and even tran­ siently stimulated) whereas photochemical energy storage monitored in light exciting both PS I and PS II was markedly diminished. Low-frequency photoacoustic measurements of the Emerson enhancement showed a spectacular change in the PS II/PS I activity balance in favor o f PS I. It was also observed that the linear portion o f the saturation curve of the far-red light effect in the Emerson enhancement was not changed by the light treatment. Those results lead to the conclusion that, in contrast to PS II, the in vivo PS I photofunctioning was resistant to strong light stress, thus confirming previous suggestions derived from in vitro studies. Estima­ tion of the redox state of the PS I reaction center by leaf absorbance measurements at ca. 820 nm suggested that, under steady illum ination, a considerably larger fraction o f PS I cen­ ters were in the closed state in high-light pretreated leaves as compared to control leaves, pre­ sumably allowing passive adjustment o f the macroscopic quantum yield o f PS I photochemis­ try to the strongly reduced photochemical efficiency o f photoinhibited PS II. 
  Reference    Z. Naturforsch. 46c, 1038—1044 (1991); received M arch 25/June 21 1991 
  Published    1991 
  Keywords    Photosystem I, Photoacoustics, Photoinhibition 
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 TEI-XML for    default:Reihe_C/46/ZNC-1991-46c-1038.pdf 
 Identifier    ZNC-1991-46c-1038 
 Volume    46 
3Author    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 
4Author    HansJ. Rurainski, Gerhard MaderRequires cookie*
 Title    The Effect of M g 2+ on the Reduction of N A D P by an Artificial Electron D onor  
 Abstract    The effect of M g 2+ on the light-dependent reduction of N A D P by an artificial electron donor has been investigated with isolated broken chloroplasts. In both short and long wavelength actinic light, addition of the salt under most conditions stimulates the yield and the saturation rate. The magnitude of the stimulation is a function of pH. T he data indicate that previous interpreta­ tions of the M g 2+ effect in this system invoking changes in the spill-over rate between the photo­ systems is no longer tenable. It is suggested that addition of the salt causes activation of inactive reaction centers. 
  Reference    Z. Naturforsch. 33c, 664 (1978); received August 7 1978 
  Published    1978 
  Keywords    Photosynthesis, Photosystem I, Cation Effect, N A D P Reduction 
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 TEI-XML for    default:Reihe_C/33/ZNC-1978-33c-0664.pdf 
 Identifier    ZNC-1978-33c-0664 
 Volume    33 
5Author    StuartM. Ridley, Peter HortonRequires cookie*
 Title    DCMU-Induced Fluorescence Changes and Photodestruction of Pigments Associated with an Inhibition of Photosystem I Cyclic Electron Flow  
 Abstract    Diuron (DCM U) induces the photodestruction o f pigm ents, w hich is the initial herbicidal symptom. As a working hypothesis, it is proposed that this sym ptom can only be produced when the herbicide dose is sufficiently high to inhibit not only photosystem II electron transport alm ost completely, but also inhibit (through over oxidation) the natural cyclic electron flow associated with photosystem I as well. Using freshly prepared chloroplasts, studies o f D C M U -induced fluorescence changes, and dose responses for inhibition o f electron transport, have been com ­ pared with a dose response for the photodestruction o f pigm ents in chloroplasts during 24 h illumination. Photodestruction o f pigm ents coincides with the inhibition o f cyclic flow. 
  Reference    Z. Naturforsch. 39c, 351 (1984); received October 10 1983 
  Published    1984 
  Keywords    Diuron (DCM U), Photodestruction, Fluorescence, Photosystem I, Cyclic Electron Flow 
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 TEI-XML for    default:Reihe_C/39/ZNC-1984-39c-0351.pdf 
 Identifier    ZNC-1984-39c-0351 
 Volume    39 
6Author    B. Urkhard Vechtel, ElfriedeK. Pistorius, H. Ans, G. Eo, RgR. UppelRequires cookie*
 Title    Occurrence of Secondary Carotenoids in PS I Complexes Isolated from Eremosphaera viridis De Bary (Chlorophyceae)  
 Abstract    Photosystem I complexes o f Eremosphaera viridis D e Bary (Chlorophyceae, Chlorococcales) were isolated and partially characterized. In the isolated PS I complexes, peptides o f 6 4 -6 0 , 26, 23, 20, 15, 11 and 8.5 kD a could be detected. When Erem osphaera was grown under regular conditions the pigment com position o f the isolated PS I com plexes was similar to that found in PS I complexes from other green algae. However, when Eremosphaera was grown under nitro­ gen deficient conditions, PS I complexes contained the secondary carotenoids canthaxanthin and traces o f astaxanthin and echinenone in addition to ß-carotene, violaxanthin and lutein. The results presented indicate that the secondary carotenoids are associated with the LHC I o f PS I. To our knowledge this represents the first report about the association o f secondary caro­ tenoids with light harvesting pigment protein complexes o f green algae. 
  Reference    Z. Naturforsch. 47c, 51—56 (1992); received July 25/September 9 1991 
  Published    1992 
  Keywords    Eremosphaera viridis, Photosystem I, Secondary Carotenoids, N-Deficiency, LHC I 
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 TEI-XML for    default:Reihe_C/47/ZNC-1992-47c-0051.pdf 
 Identifier    ZNC-1992-47c-0051 
 Volume    47 
7Author    Gudrun Wälzlein, ElfriedeK. PistoriusRequires cookie*
 Title    Inactivation of Photosynthetic 0 2 Evolution in the Cyanobacterium Anacystis nidulans PCC 6301: Influence of Nitrogen Metabolites and Divalent Cation Concentration  
 Abstract    A n investigation about the in vivo inactivation o f photosynthetic water oxidation has been carried out in the cyanobacterium Anacystis nidulans (Synechococcus PC C 6301). Photosystem II and photosystem I activity as well as the relative am ount of the D 1 and manganese stabiliz­ ing peptide o f photosystem II were determined after growing the cells in nutrient media with variations in the nitrogen source and the concentration of the major divalent cations (M g 2+ and C a :+). The results show a rapid inactivation of water oxidation in A. nidulans in response to nitrogen deficiency and in response to reduced M g:+ and C a2+ concentrations. The inactiva­ tion o f water oxidation observed under divalent cation deficiency could be greatly accelerated when L-amino acids instead o f am m onia or nitrate were used as nitrogen source. Under these conditions inactivation o f water oxidation correlated with a rapid loss o f D 1 and with a slower loss o f the manganese stabilizing peptide from photosystem II. A possible regulation o f the photosystem II activity in A. nidulans by nitrogen metabolites is suggested. 
  Reference    Z. Naturforsch. 46c, 1024—1032 (1991); received June 26/August 19 1991 
  Published    1991 
  Keywords    Cyanobacteria, Anacystis nidulans PCC6301, Synechococcus PCC6301, Photosystem II, Photosystem I, Nitrogen Metabolism 
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 TEI-XML for    default:Reihe_C/46/ZNC-1991-46c-1024.pdf 
 Identifier    ZNC-1991-46c-1024 
 Volume    46