Photosynthetic Oxygen Evolution in Mesoporous Silica Material: Adsorption of Photosystem II Reaction Center Complex into 23 nm Nanopores in SBA

Langmuir ◽  
2011 ◽  
Vol 27 (2) ◽  
pp. 705-713 ◽  
Author(s):  
Tomoyasu Noji ◽  
Chihiro Kamidaki ◽  
Keisuke Kawakami ◽  
Jian-Ren Shen ◽  
Tsutomu Kajino ◽  
...  
2007 ◽  
Vol 833 (1-3) ◽  
pp. 169-174 ◽  
Author(s):  
R. Beauchemin ◽  
J. Harnois ◽  
R. Rouillon ◽  
H.A. Tajmir-Riahi ◽  
R. Carpentier

1997 ◽  
Vol 52 (3-4) ◽  
pp. 175-179 ◽  
Author(s):  
W. I. Gruszecki ◽  
K. Strzałka ◽  
A. Radunz ◽  
G. H. Schmid

Abstract Photosynthetic oxygen evolution from photosystem II particles was analyzed as consequence of a train of short (5 μs) flashes of different light quality and different intensities to study cyclic electron flow around photosystem II. Damped oscillations of the amplitudes of O2-evolution corresponding to a flash sequence were fitted numerically and analyzed in terms of a nonhomogeneous distribution of misses, represented by the probability parameter αi. Application of red light, known to promote cyclic electron flow around photosystem II (Gruszecki et al., 1995) results in a considerable increase of all αi, indicating that at the molecular level the misses may be interpreted as resulting from a competition for the reduction of oxidized P680 between cyclic electron flow and the electron flow coming from the water splitting enzyme. In accordance with previous findings, application of light flashes of the spectrum covering the absorption region of carotenoids resulted in an inhibition of cyclic electron flow and a pronounced decrease of the level of the miss parameter. Possible molecular mechanisms for the activity control of this cyclic electron transport around photosystem II by carotenoids are discussed.


2017 ◽  
Vol 72 (7-8) ◽  
pp. 315-324 ◽  
Author(s):  
Ekaterina K. Yotsova ◽  
Martin A. Stefanov ◽  
Anelia G. Dobrikova ◽  
Emilia L. Apostolova

AbstractThe effects of short-term treatment with phenylurea (DCMU, isoproturon) and phenol-type (ioxynil) herbicides on the green algaChlorella kessleriand the cyanobacteriumSynechocystis salinawith different organizations of photosystem II (PSII) were investigated using pulse amplitude modulated (PAM) chlorophyll fluorescence and photosynthetic oxygen evolution measured by polarographic oxygen electrodes (Clark-type and Joliot-type). The photosynthetic oxygen evolution showed stronger inhibition than the PSII photochemistry. The effects of the studied herbicides on both algal and cyanobacterial cells decreased in the following order: DCMU>isoproturon>ioxynil. Furthermore, we observed that the number of blocked PSII centers increased significantly after DCMU treatment (204–250 times) and slightly after ioxynil treatment (19–35 times) in comparison with the control cells. This study suggests that the herbicides affect not only the acceptor side but also the donor side of PSII by modifications of the Mn cluster of the oxygen-evolving complex. We propose that one of the reasons for the different PSII inhibitions caused by herbicides is their influence, in different extents, on the kinetic parameters of the oxygen-evolving reactions (the initial S0−S1state distribution, the number of blocked centers SB, the turnover time of Sistates, misses and double hits). The relationship between the herbicide-induced inhibition and the changes in the kinetic parameters is discussed.


1997 ◽  
Vol 52 (9-10) ◽  
pp. 636-638 ◽  
Author(s):  
Shigetoh Miyachi ◽  
Kerstin Strassdat ◽  
Hideaki Miyashita ◽  
Horst Senger

The recently isolated and characterized unicellular photosynthetic prokaryote Acaryochloris marina (Miyashita et al., 1996) contains chlorophylls a, d , and traces of a chlorophyll c-like pigment as well as phycocyanin. a type of allophycocyanin, zeaxanthin and cx-carotene, chlorophyll d being the predominant chlorophyll component. Quantum requirement measurements of the photosynthetic oxygen evolution resulted in about 12 quanta for excitation of chlorophylls a and d and 18 for phycocyanin. The data also revealed that these pigments are involved in energy absorption for photosynthetic oxygen evolution. Energy is transferred efficiently and equally well between the chlorophylls. Light absorbed by phycocyanin which is organized in phycobiliprotein aggregates (M arquardt et al., 1997), results in a less efficient energy transfer to the reaction center chlorophylls


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