Go toArchive
Browse byFacets
Bookbag ( 0 )
'Photosynthesis' in keywords
Results  112 Items
Sorted by   
Publication Year
1999 (8)
1997 (2)
1996 (4)
1995 (2)
1994 (1)
1993 (6)
1992 (2)
1991 (2)
1990 (5)
1989 (2)
1Author    Friederike Koenig, Wilhelm Menke, Hans Craubner, GeorgH. Schmid, Alfons RadunzRequires cookie*
 Title    Photochemically Active Chlorophyll-Containing Proteins from Chloroplasts and their Localization in the Thylakoid Membrane  
 Abstract    After solubilization of stroma-freed chloroplasts with deoxycholate, the lipids and the detergent used are separated from the proteins by gel filtration. In this way not denatured pigment-con-taining protein preparations were obtained. The particles in fraction 1 exhibited a molecular weight of 600 000 and contained an average of 25 chlorophyll molecules. The circular dichroism spectrum showed exciton splitting of the red band. The particles in fraction 2 contained 1 chloro-phyll molecule and exhibited a molecular weight of 110 000. The particles in fraction 3 also contained only 1 chlorophyll molecule and had a molecular weight of between 80 000 and 100 000. Pure preparations of fraction 1 only carried out the methylviologen M e h 1 e r reaction with the dichlorophenol indophenol/ascorbate couple as electron donor. Fraction 3 only reduced ferri-cyanide with diphenylcarbazide as an electron donor in the light. Fraction 2 exhibited both the photosystem I reaction and the photosystem II reaction. An antiserum to extracted fraction 1 does not inhibit electron transport in the intact lamellar system. The photoreduction of methylviologen is only inhibited after disruption of the thylakoids. The antiserum to fraction 2 inhibits the photo-reduction of methylviologen in the intact lamellar system. Consequently, one inhibition site for this photosystem I reaction must be located on the inner and another on the outer surface of the thylakoid membrane. In addition, antibodies to fraction 1 are specifically adsorbed onto the lamellar system without any effect on electron transport and without a concomitant agglutination. Antibodies to fraction 3 partially inhibit the photoreduction of ferricyanide with diphenylcarbazide as an electron donor in the intact lamellar system. Hence, the inhibition site of this system II reaction is located on the outer surface of the thylakoids. We have reason to believe that the inhibition sites not reacting are located in the partitions, which are not accessible to antibodies. 
  Reference    (Z. Naturforsch. 27b, 1225 [1972]; received July 5 1972) 
  Published    1972 
  Keywords    Chloroplasts, membranes, proteins, photosynthesis, antibodies 
  Similar Items    Find
 TEI-XML for    default:Reihe_B/27/ZNB-1972-27b-1225.pdf 
 Identifier    ZNB-1972-27b-1225 
 Volume    27 
2Author    Jeffrey Karan, SeymourSteven BrodyRequires cookie*
 Title    Chlorophyll a and Cytochrome c at a Heptane-Water Interface  
 Abstract    The surface pressure was measured as a function of area/molecule for chlorophyll a (Chi) and cytochrome c (Cyt) at a heptane-water interface. At a surface pressure of 6 dyn/cm the area per molecule of C h l(^ 6) = 1 1 3 ±6 Ä 2, for reduced Cyt c (red. Cyt) the A6 = 5000 ± 300 Ä 2 and for oxidized Cyt c (ox. Cyt) /3(6=4100 ± 250 A2. Cyt appears to denature at the interface. Irradiation results in a decrease of the for Chi to ^ 8 = 1 0 0 ± 5 Ä 2. There appears to be interaction between Chi and red. Cyt in a mixed film no interaction is observed between Chi and ox. Cyt. 
  Reference    (Z. Naturforsch. 29c, 506 [1974]; received June 14 1974) 
  Published    1974 
  Keywords    Chlorophyll, Cytochrome, Monolayers, Photosynthesis, Membranes 
  Similar Items    Find
 TEI-XML for    default:Reihe_C/29/ZNC-1974-29c-0506.pdf 
 Identifier    ZNC-1974-29c-0506 
 Volume    29 
3Author    SeymourSteven BrodyRequires cookie*
 Title    Surface Properties of Monomolecular Films of Reduced Plastocyanin at a Nitrogen-Water Interface  
 Abstract    The area/molecule (A) and surface potential {A V) of reduced plastocyanin (pcyan) was measured as a function of pH. At pH 7.5 a maximum is observed for A while a minimum is ob­ served for A V . At a surface pressure of 5 dyn/cm the maximum ^ 5 = 378 Ä 2 and minimum A V 5 = 335 mV. There is an interaction between pcyan and chlorophyll (Chi) in mixed films. As shown by a decrease of A and V compared to theoretically calculated volues. The largest decrease occurs at a mol ratio of about 2 pcyan: 1 Chi. When mixed films are irradiated in air no changes in surface properties are observed. Irradiation of mixed films of reduced pcyan and Chi in nitrogen results in a decrease in A and an increase of AV. The maximum decrease occurs at a mol ratio of pcyan/Chl between 1.5 and 2.0. The direction of change of A is consistant with a conversion of reduced pcyan to oxidized pcyan. 
  Reference    (Z. Naturforsch. 30c, 318 [1975]; received October 4 1974) 
  Published    1975 
  Keywords    Plastocyanin, Photosynthesis, Monolayers, Model Membranes 
  Similar Items    Find
 TEI-XML for    default:Reihe_C/30/ZNC-1975-30c-0318.pdf 
 Identifier    ZNC-1975-30c-0318 
 Volume    30 
4Author    A. Trebst, H. WietoskaRequires cookie*
 Title    Hemmung des photosynthetischen Elektronentransports von Chloroplasten durch Metribuzin * Mode of Action and Structure-Acitivity-Relationships of the Aminotriazinone Herbicide Metribuzin Inhibition of Photosynthetic Electron Transport in 'Chloroplasts by M etribuzin  
 Abstract    The influence of the aminotriazinone herbicide Metribuzin on photosynthetic reactions of iso­ lated chloroplasts is investigated. Metribuzin inhibits all Hill-reactions when water is the electron donor, but not photoreductions by photosystem I at the expense of an artificial electron donor. The PIso-value is 6.7. Cyclic photophosphorylation is not affected by Metribuzin. Measurements of the prompt and delayed fluorescence of the photosynthetically active chlorophyll support the notion, that Metribuzin inhibits photosynthetic electron flow between the primary and secondary electron acceptor of photosystem II (Q and plastoquinone). The relationship of inhibitory potency to chemical structure is investigated by comparing a number of related aminotriazinones. The effect of various substituents is discussed. E in le itu n g 
  Reference    (Z. Naturforsch. 30c, 499 [1975]; eingegangen am 7. April 1975) 
  Published    1975 
  Keywords    Photosynthesis, Chloroplasts, Herbicide, Metribuzin, Aminotriazinone 
  Similar Items    Find
 TEI-XML for    default:Reihe_C/30/ZNC-1975-30c-0499.pdf 
 Identifier    ZNC-1975-30c-0499 
 Volume    30 
5Author    Wilhelm Menke, Friederike Koenig, GeorgH. Schmid, Alfons RadunzRequires cookie*
 Title    Functional Characterization of Four Thylakoid Membrane Polypeptides with Apparent Molecular Weights between 40 000 and 48 000  
 Abstract    Four polypeptides which exhibited apparent molecular weights from 40 000 to 48 000 were isolated from the thylakoid membrane. The isolation was achieved by gel filtration of polypeptides, solubilized by means of sodium dodecyl sulfate and, after removal of detergent by anion exchange chromatography in ethanolic solution. The polypeptide of the molecular weight 40000 was iden­ tified as the 7-component of the coupling factor of photophosphorylation via the effect of its 
  Reference    Z. Naturforsch. 33c, 280 (1978); received February 27 1978 
  Published    1978 
  Keywords    Thylakoid Membrane Polypeptides, Antisera, Photosynthesis 
  Similar Items    Find
 TEI-XML for    default:Reihe_C/33/ZNC-1978-33c-0280.pdf 
 Identifier    ZNC-1978-33c-0280 
 Volume    33 
6Author    J.J S Van Rensen, D. Wong, GovindjeeRequires cookie*
 Title    Characterization of the Inhibition of Photosynthetic Electron Transport in Pea Chloroplasts by the Herbicide 4,6-Dinitro- o-cresol by Comparative Studies with 3-(3,4-Dichlorophenyl)-l,l- dimethylurea  
 Abstract    An attempt to characterize the mechanism of inhibition of photosynthetic electron transport in isolated pea chloroplasts by the herbicide 4,6-dinitro-o-cresol (DNOC) by a comparison with the effects of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) revealed the following: 
  Reference    Z. Naturforsch. 33c, 413 (1978); received April 12 1978 
  Published    1978 
  Keywords    Photosynthesis, Electron Transport, Fluorescence, Herbicides 
  Similar Items    Find
 TEI-XML for    default:Reihe_C/33/ZNC-1978-33c-0413.pdf 
 Identifier    ZNC-1978-33c-0413 
 Volume    33 
7Author    GeorgH. Schmid, Pierre ThibaultRequires cookie*
 Title    Evidence for a Rapid Oxygen-Uptake in Tobacco Chloroplasts  
 Abstract    A fast oxygen uptake, induced by a sequence of short (5 /usee) saturating flashes was observed in chloroplasts of wild type tobacco and two chlorophyll-deficient tobacco mutants. One of the chlorophyll mutants is the earlier described variegated tobacco NC 95. Chloroplasts of this mutant exhibit only photosystem I mediated photoreactions, hence the observed oxygen uptake is to be associated with photosystem I. This is further substantiated by the fact that the oxygen uptake is insensitive to DCMU in the two chloroplast types used, which have both photosystems fully func­ tioning. The uptake depends on the addition of electron acceptors like p-benzoquinone in intact chloroplasts or on p-benzoquinone or ferricyanide in chloroplasts that have lost the envelope. In dark adapted chloroplasts, therefore, under these conditions the overall apparent gas exchange in the first two flashes is consumption. Although the uptake is slower than photosynthetic oxygen evolution it clearly affects the oxygen yield in the flash sequences. This is demonstrated by several experiments in which the apparent oxygen consumption in the absence of DCMU oscillates with a periodicity of four. We have indications that in chloroplasts of the tobacco aurea mutant Su/su the oxygen uptake is faster than in wild type chloroplasts. 
  Reference    Z. Naturforsch. 34c, 414 (1979); received February 14 1979 
  Published    1979 
  Keywords    Chloroplasts, Oxygen uptake, Oscillations, Photosynthesis 
  Similar Items    Find
 TEI-XML for    default:Reihe_C/34/ZNC-1979-34c-0414.pdf 
 Identifier    ZNC-1979-34c-0414 
 Volume    34 
8Author    K.H G Rum BachRequires cookie*
 Title    Evidence for the Existence of Two ^-Carotene Pools and Two Biosynthetic ^-Carotene Pathways in the Chloroplast  
 Abstract    Two /7-Carotene pools were obtained in the chloroplast. It is concluded that one pool is very small like a-carotene and responsible exclusively for the biosynthesis of /?-ionone-xanthophylls. The other ^-carotene pool is proposed to be the one, that is located close to photosystem I and is involved in photosynthesis as a light protecting agent for chlorophylls against photo-oxidation. Furtherm ore evidence is given that both /7-carotene pools are synthesized by independent biosyn­ thetic pathways. 
  Reference    Z. Naturforsch. 34c, 1205 (1979); received Septem ber 4 1979 
  Published    1979 
  Keywords    Biosynthesis, Carotenoids, /?-Carotene, Photosynthesis 
  Similar Items    Find
 TEI-XML for    default:Reihe_C/34/ZNC-1979-34c-1205.pdf 
 Identifier    ZNC-1979-34c-1205 
 Volume    34 
9Author    David Pan, KimH. TanRequires cookie*
 Title    Evidence for a Transcarboxylase Reaction in M aize Chloroplast Extracts  
 Abstract    The authors have suggested (Can. J. Bot. 49, 631 (1971) that the — COOH group of the C4-P carbonyl compound of the thermostable P-enolpyruvate acid carboxylase reaction may transcarboxylase with a pentose phosphate as ac­ ceptor. We now have considerable evidence supporting this consideration. In an assay system (0.8 ml) containing soni­ cated chloroplast extract in 0.1 m Tris-HCl, pH 6.3; and PEP, 0.1 |imol; Mg2+, 0.5 nmol; NADH, 0.25 nmol; sugar phosphate, 0.5 nmol. The amount of 14C 0 2 fixation is con­ siderably enhanced by either ribose-5-phosphate, fructose-1,6-bisphosphate or ribulose-l,5-bisphosphate in the pres­ ence of PEP. The products of the reaction include malate as a product of /?-carboxylation, and glycerate or 3-phosphate glycerate, their proportion being determined by the ac­ ceptor sugar phosphate. The results provide evidence for a "transcarboxylase" presented in the crude extract of Maize chloroplasts. 
  Reference    Z. Naturforsch. 36c, 688—691 (1981); received December 11 1980/February 27 1981 
  Published    1981 
  Keywords    Photosynthesis, Chloroplasts, C4 Plants, Transcarboxylase 
  Similar Items    Find
 TEI-XML for    default:Reihe_C/36/ZNC-1981-36c-0688_n.pdf 
 Identifier    ZNC-1981-36c-0688_n 
 Volume    36 
10Author    K. H. GrumbachRequires cookie*
 Title    Interconversion of Carotenoids and Quinones after Onset of Photosynthesis in Chloroplasts of Higher Plants  
 Abstract    The interconversion of carotenoids and quinones was investigated in beech and spinach leaves as well as isolated intact spinach chloroplasts following a dark-light transition. It is shown that isolated intact chloroplasts which are preincubated for 2 h at pH 7.6 in the dark and re­ illuminated with strong white light are capable not only o f deepoxidizing violaxanthin into antheraxanthin and zeaxanthin but simultaneously change the redox state o f the plastoquinone-pool in their thylakoid membrane. At the same time as violaxanthin is deepoxidized plasto-hydroquinone-9 is oxidized to plastoquinone-9. If the light is turned off zeaxanthin is epoxidized into antheraxanthin and violaxanthin but no significant change in the redox state o f the plasto-quinone-pool occurred. It is concluded that the deepoxidation of violaxanthin is connected to the photosynthetic electron transport in that way that an acidification o f the intrathylakoidal compartment by the vectorial release of protons from the water photooxidizing enzyme system and the plastoquinone-pool is required for the activation of the violaxanthin deepoxidase. This may be taken as further evidence that violaxanthin deepoxidase is located at the inner side o f the thylakoid membrane. Additional evidence for this location site is given by the observation that neither deepoxidation of violaxanthin nor photooxidation of plastohydroquinone-9 occurred after onset o f photosyn­ thesis if non cyclic electron transport was inhibited by DCMU. 
  Reference    Z. Naturforsch. 38c, 393 (1983); received March 15 1983 
  Published    1983 
  Keywords    Carotenoids, Photosynthesis, Quinones, Xanthophyll Cycle 
  Similar Items    Find
 TEI-XML for    default:Reihe_C/38/ZNC-1983-38c-0393.pdf 
 Identifier    ZNC-1983-38c-0393 
 Volume    38 
11Author    A. Trebst, B. D. Epka, S. M. Ridley, A. F. HawkinsRequires cookie*
 Title    Inhibition of Photosynthetic Electron Transport by Halogenated 4-Hydroxy-pyridines  
 Abstract    Herbicidal halogen substituted 4-hydroxypyridines are inhibitors of photosynthetic electron flow in isolated thylakoid membranes by interfering with the acceptor side of photosystem II. Tetrabromo-4-hydroxypyridine, the most active compound found, has a pl50-value of 7.6 in the inhibition of oxygen evolution in both the reduction of an acceptor of photosystem I and an acceptor of photosystem II. The new inhibitors displace both metribuzin and ioxynil from the membrane. The 4-hydroxypyridines, like ioxynil, have unimpaired inhibitor potency in Tris-treated chloroplasts, whereas the DCMU-type family of herbicides does not. It is suggested that 4-hydroxypyridines are complementary to phenol-type inhibitors, and a common essential element is proposed. The 4-hydroxypyridines do not inhibit photosystem I or non-cyclic electron flow through the cytochrome b/f complex. But they do have a second inhibition site in photosynthetic electron transport since they inhibit ferredoxin-catalyzed cyclic electron flow, indicating an antimycin-like property. A comparison of the in vitro potency of the compounds with the in vivo potency shows no correlation. A major herbicidal mode of action of the group is related to the inhibition of carotenoid synthesis, and access to the chloroplast lamellae in vivo for inhibition of electron transport may be restricted. 
  Reference    Z. Naturforsch. 40c, 391—399 (1985); received February 28 1985 
  Published    1985 
  Keywords    Herbicides, Hydroxypyridines, Inhibitors, Photosynthesis 
  Similar Items    Find
 TEI-XML for    default:Reihe_C/40/ZNC-1985-40c-0391.pdf 
 Identifier    ZNC-1985-40c-0391 
 Volume    40 
12Author    SeymourSteven Brody, George Papageorgiou, Katerina Alygizaki-ZorbaRequires cookie*
 Title    Photodynamic Action of Hypericin on Cyanobacteria, Synechocystis and Synechoccus (Anacystis nidulans)  
 Abstract    The photodynamic action of hypericin on photosynthesis and respiration were monitored in Synechocystis sp PCC 6803 and Synechoccus A TC C 6311 (Anacystis nidulans). An oxygen electrode was used to measure net oxygen evolution or consumption. The amount o f hyperi­ cin required to inhibit photosynthesis was quantitively determined. Photosynthesis was com­ pletely inhibited in Synechocystis when the molar ratio of chlorophyll/hypericin was about 70:1. Higher concentrations o f hypericin did not stop the uptake of oxygen, but rather stim­ ulated the process in the light. Hypericin was readily washed out o f the cells forming no permanent associations in the bacterial cell. Hypericin inhibited electron transfer and conse­ quently oxygen production by PSII particles. For half maximum inhibition o f oxygen evolu­ tion, with PSII membrane particles, the molar ratio of chlorophyll/hypericin was about 10:1. 
  Reference    Z. Naturforsch. 52c, 165—168 (1997); received November 14. 1996/January 15 1997 
  Published    1997 
  Keywords    Hypericin, Cyanobacteria, Photosynthesis, Photodynamic Action 
  Similar Items    Find
 TEI-XML for    default:Reihe_C/52/ZNC-1997-52c-0165.pdf 
 Identifier    ZNC-1997-52c-0165 
 Volume    52 
13Author    Zbigniew KrupaRequires cookie*
 Title    Cadmium against Higher Plant Photosynthesis -a Variety of Effects and Where Do They Possibly Come From?  
 Abstract    2 0 -0 3 3 Lublin, Poland. Fax: (48-81) 5 3 7 5 1 0 2 . E-mail: zkrupa@biotop.umcs.lublin.pl The complexity of in vivo toxic effects of Cd on higher plants makes almost impossible an accurate distinction between direct and indirect mechanisms of its action on the photosyn­ thetic apparatus. We, therefore, postulate that multiple Cd effects on plant physiological and metabolic processes may finally be focused on photosynthesis. This would also explain the phenomenon that only a small fraction of Cd entering chloroplasts may cause such disastrous changes in their structure and function. In return, the inhibition of photosynthesis affects numerous metabolic pathways dependent on the primary carbon metabolism. 
  Reference    Z. Naturforsch. 54c, 723 (1999); received D ecem ber 15 1998/M arch 2 1999 
  Published    1999 
  Keywords    Cadmium, Higher Plants, Photosynthesis 
  Similar Items    Find
 TEI-XML for    default:Reihe_C/54/ZNC-1999-54c-0723.pdf 
 Identifier    ZNC-1999-54c-0723 
 Volume    54 
14Author    A. Trebst, E. HarthRequires cookie*
 Title    Herbicidal N-Alkylated-Ureas and Ringclosed N-Acylamides as Inhibitors of Photosystem II  
 Abstract    The inhibitory action of some herbicides on photosynthetic electron flow at photosystem I I in isolated chloroplasts was investigated. Emphasis in the study is on compounds, whose chemical structure seemed to be in disaccordance with the basic structural element, proposed to be required for a photosystem II inhibitor. The effective inhibition of photosynthetic oxygen evolution by N-alkylated urea-, pyrrolidone-and by substituted pyridazine-derivatives without a free NH-group is reported. A revised basic chemical structural element responsible for inhibition is deduced in order to include lactames (ringclosed N-acylamides) with and without hetero atoms. From this new groups of potential inhibitors, like triazolone-, thiadiazolone-and oxadiazolone-derivatives may be conceived. 
  Reference    (Z. Naturforsch. 29c, 232 [1974]; received February 4 1974) 
  Published    1974 
  Keywords    Inhibitor, Herbicides, Photosynthesis, Photosystem II, Chloroplasts 
  Similar Items    Find
 TEI-XML for    default:Reihe_C/29/ZNC-1974-29c-0232.pdf 
 Identifier    ZNC-1974-29c-0232 
 Volume    29 
15Author    GeorgH. Schmid, Alfons Radunz, Wilhelm MenkeRequires cookie*
 Title    The Effect of an Antiserum to Plastocyanin on Various Chloroplast Preparations  
 Abstract    A monospecific antiserum to tobacco plastocyanin agglutinates strom a-free sw ellable chloroplasts from wild type tobacco, (N ico tia n a tabacum var. John William's Broadleaf) from the tobacco aurea mutant Su/su2, (N ico tia n a tabacum var. Su/su2) from A ntirrh in um m aju s and spinach (Spi-nacia o lera cea). In this condition the antiserum inhibits linear photosynthetic electron flow in tobacco and spinach chloroplasts. This inhibition of electron transport as well as the agglutination are not observed if the chloroplasts have been sonicated prior to antiserum addition. This is due to the fact that plastocyanin is removed by ultrasonication. The antiserum stimulates a number of photophosphorylation reactions in tobacco chloroplasts. This stimulation is always larger in the aurea mutant chloroplasts and in chloroplasts from yellow leaf patches of a variegated tobacco mutant (N . tabacu m , var. N C 95) than in the green type chloroplasts. The stimulation appears to be a consequence of the inhibition of linear electron transport. The antiserum does not affect PMS-mediated cyclic photophosphorylation in tobacco chloroplasts from the wild type whereas the reaction appears stimulated in the tobacco mutant chloroplasts. However, menadione-mediated cyclic photo­ phosphorylation is inhibited upon addition of the antiserum. The same is true for noncyclic photo­ phosphorylation coupled to electron transport in the aerobic system diaminodurene/ascorbate — > methylviologen in the presence of N-tetraphenyl-p-phenylenediamine in spinach chloroplasts. If the lamellar system of A n tirrh in u m and spinach has lost its swellability neither agglutination nor inhibition of electron transport is observed. However, also in this state antibodies to plasto­ cyanin are specifically adsorbed onto the surface of the thylakoid membrane. This state which is characterized by a morphologically well preserved lamellar system is realized in chloroplast prepa­ rations from A n tirrh in um and spinach and is termed stroma-freed, chloroplasts. In both states of the molecular structure of the thylakoid membrane, plastocyanin is located in the outer surface of the thylakoid. However, it cannot be excluded that functioning plastocyanin is also located in the interior of the thylakoid membrane. 
  Reference    (Z. Naturforsch. 30c, 201 [1975]; received December 9 1974) 
  Published    1975 
  Keywords    Photosynthesis, Plastocyanin, Antibodies, Chlorophyll-deficient Tobacco Mutants 
  Similar Items    Find
 TEI-XML for    default:Reihe_C/30/ZNC-1975-30c-0201.pdf 
 Identifier    ZNC-1975-30c-0201 
 Volume    30 
16Author    HansJ. RurainskiRequires cookie*
 Title    Antagonistic Relationships between Electron Transport and P700 in Chloroplasts and Intact Algae  
 Abstract    The effects of divalent salts and 3-(3,4-dichlorophenyl) -1,1-dimethylurea (DCMU) upon nicotin­ amide adenine dinucleotide phosphate (NADP) reduction and P700 in isolated chloroplasts are described and compared with the influence of DCMU on oxygen evolution and P700 in intact cells. Most experiments were carried out with a steady-state relaxation spectrometer. A kinetic mechanism for the estimation of P700 fluxes is proposed and experimentally tested. Good agreement between theory and experiment was found. Concurrent measurements of P700 and NADP reduction revealed two antagonisms: addition of divalent cations caused an increase in the yield of NADP reduction and a decrease in the yield of P700 . Conversely, in the presence of Mg2+ low concentrations of DCMU decreased the yield of NADP reduction and increased the yield of P700 . Aging of the chloroplasts at 30 °C exerted a similar effect. With far-red actinic light, Mg2* stimulated the yield of NADP reduction without affecting the flux. Also, in the absence of Mg2+ , DCMU inhibited both reactions although P700 required a higher herbicide concentration for fractional inhibition than NADP reduction. In the presence of Mg2*, chloroplasts resembled intact algae in which a high rate of oxygen evolution was accompanied by little P700 turn-over. Titration with DCMU decreased the rate of photosynthesis and increased P700 flux. On the whole, the data suggest that P700 relaxing in 20 msec is not directly involved in linear electron transport. 
  Reference    (Z. Naturforsch. 30c, 761 [1975]; received July 23 1975) 
  Published    1975 
  Keywords    Relaxation Spectroscopy, Photosynthesis, NADP Reduction, Cation Effects 
  Similar Items    Find
 TEI-XML for    default:Reihe_C/30/ZNC-1975-30c-0761.pdf 
 Identifier    ZNC-1975-30c-0761 
 Volume    30 
17Author    G. Ünter, D. Ö. RinRequires cookie*
 Title    The Effect of Deoxycholate-Treatment to the Photoreactions of the Active Pigments in Photosynthesis  
 Abstract    In the heavy fraction of deoxycholate-treated spinach chloroplasts the chlorophyll an activity is high and the chlorophyll a\ activity is low when no artificial electron donor is added. The addition of the photosystem I donor system N-methyl-phenazonium sulphate plus sodium ascorbate (PMS + Asc) leads to a complete reactivation of the chlorophyll ai reaction. The addition of the photo­ system II donor system p-benzohydroquinone plus sodium ascorbate (HQ + Asc) leads to an inhibi­ tion of the chlorophyll an activity. From these results we conclude: 1. Besides an interruption of the linear electron flow between the two photosystems deoxycholate-treatment leads to a block of the electron flow from water to photosystem II. 2. In deoxycholate-treated chloroplasts the linear electron flow in photosystem II just like in Tris­ washed, heat-treated or aged chloroplasts, is replaced by a cyclic one. 
  Reference    (Z. Naturforsch. 31c, 64 [1976]; received August 19 1975) 
  Published    1976 
  Keywords    Photosynthesis, Deoxycholate-Treatment, Electron Transport, Flash Excitation 
  Similar Items    Find
 TEI-XML for    default:Reihe_C/31/ZNC-1976-31c-0064.pdf 
 Identifier    ZNC-1976-31c-0064 
 Volume    31 
18Author    G. Ünter, D. Ö. RinRequires cookie*
 Title    The Chlorophyll an Reaction in Trypsin-Treated Spinach Chloroplasts in the Presence of Potassium Ferricyanide  
 Abstract    In trypsin-treated spinach chloroplasts there is no linear electron flow from water to potassium ferricyanide. The chlorophyll a n reaction, however, is still active but insensitive to 3-(3,4-dichloro-phenyl)-l,l-dimethylurea. From this we conclude that ferricyanide and trypsin together stimulate a mini-cycle in photosystem II. 
  Reference    (Z. Naturforsch. 31c, 78 [1976]; received July 29/October 15 1975) 
  Published    1976 
  Keywords    Photosynthesis, Photosystem II, Trypsin-Treatment, Flash Excitation 
  Similar Items    Find
 TEI-XML for    default:Reihe_C/31/ZNC-1976-31c-0078.pdf 
 Identifier    ZNC-1976-31c-0078 
 Volume    31 
19Author    Wilhelm Menke, Alfons Radunz, GeorgH. Schmid, Friederike Koenig, Rolf-Dieter HirtzRequires cookie*
 Title    Intermolecular Interactions of Polypeptides and Lipids in the Thylakoid Membrane  
 Abstract    Intermolecular interactions between chloroplast lipids and a polypeptide fraction from thylakoids were investigated by far ultraviolet circular dichroism. The polypeptide fraction was isolated from dodecyl sulfate-containing buffers. It exhibits an average molecular weight of 24 000. The circular dichroism of this polypeptide fraction measured as mean residue ellipticity is greater in the presence of sodium dodecyl sulfate than in the absence of this detergent. This effect is reversible. Addition of sulfoquinovosyl diglyceride to the dodecyl sulfate-free solution of the polypeptide also causes an increase of the circular dichroism. This increase was only observed in the pH-range between 6.9 and 7.4. The effect of dodecyl sulfate or sulfolipid on the circular dichroism is inter­ preted to indicate an increase of a-helix content. Monogalactosyl diglyceride, digalactosyl di­ glyceride and phosphatidyl glycerol gave no reaction. The attempt to obtain a conformational analysis of the polypeptide in the different states did not yield an entirely satisfactory result. Anti­ sera to sulfolipid inhibit photosynthetic electron transport of stroma-freed chloroplasts in the region of light reaction I. This inhibition is restricted to the same pH-range as the non-covalent binding of sulfolipid to the polypeptides. It appears that in the cell membrane-bound metabolic processes are regulated by this pH-dependence of the sulfolipid-polypetide interactions. 
  Reference    (Z. Naturforsch. 31c, 436 [1976]; received April 30 1976) 
  Published    1976 
  Keywords    Interactions, Polypeptides, Lipids, Thylakoid Membrane, Photosynthesis 
  Similar Items    Find
 TEI-XML for    default:Reihe_C/31/ZNC-1976-31c-0436.pdf 
 Identifier    ZNC-1976-31c-0436 
 Volume    31 
20Author    S. S. Brody, N. F. OwensRequires cookie*
 Title    Photosynthetic Electron Carriers at a Heptane-Water Interface  
 Abstract    Surface properties of monomolecular films of chlorophyll (Chi), plastocyanin (Pc), cytochrome c (Cyt) and ferridoxin (Fd) were measured at a heptane-water interface. Mixed films of Chi and the other components were examined in darkness and in light. The area/molecule, A, for Fd (from Cl. pasteurianum) is much larger at a heptane-water than Fd (from spinach) at an air-water interface. This difference in A may be the source of the Fd or the extent of denaturation at the different interfaces. There appears to be a photoreaction between Chi and Fd in the presence of ascorbate. The A for Cyt is much larger at a heptane-water than at an air-water interface. In mixed films there is a strong interaction between Chi and reduced Cyt in the dark. No such interaction is ob­ served between Chi and oxidized Cyt. With mixed films of Chi and reduced Pc there is a significant, reversible, light induced change in A V. 
  Reference    (Z. Naturforsch. 31c, 569 [1976]; received May 13 1976) 
  Published    1976 
  Keywords    Monolayers, Artificial Membranes, Photosynthesis, Lipid-Water Interface, Photobiology 
  Similar Items    Find
 TEI-XML for    default:Reihe_C/31/ZNC-1976-31c-0569.pdf 
 Identifier    ZNC-1976-31c-0569 
 Volume    31