Different sensitivities of photosystem II in green algae and cyanobacteria to phenylurea and phenol-type herbicides: effect on electron donor side

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.

Genome ◽  
1993 ◽  
Vol 36 (3) ◽  
pp. 483-488 ◽  
Author(s):  
Shao-Bing Hua ◽  
Shyam K. Dube ◽  
Shain-dow Kung

Photosystem II psbP protein of the oxygen-evolving complex is involved in the photosynthetic oxygen evolution in plants. Four psbP polypeptides were detected in Nicotiana tabacum on a two-dimensional gel by immunostaining the proteins with antiserum against the pea psbP Comparison of the protein patterns of psbP from N. tabacum and its ancestral parents, N. sylvestris and N. tomentosiformis, indicated that each of the ancestral parents has contributed a pair of psbP proteins. This was supported by Southern hybridization results, which suggested that psbP in Nicotiana is encoded by a gene family consisting of four members in N. tabacum and two members each in N. glauca, N. langsdorffii, N. sylvestris, and N. tomentosiformis. A scheme of molecular evolution of the psbP genes in Nicotiana is also proposed.Key words: molecular evolution, Nicotiana, oxygen evolution, photosystem II.


2007 ◽  
Vol 833 (1-3) ◽  
pp. 169-174 ◽  
Author(s):  
R. Beauchemin ◽  
J. Harnois ◽  
R. Rouillon ◽  
H.A. Tajmir-Riahi ◽  
R. Carpentier

2003 ◽  
Vol 30 (7) ◽  
pp. 797 ◽  
Author(s):  
Vyacheslav V. Klimov ◽  
Suleyman I. Allakhverdiev ◽  
Yoshitaka Nishiyama ◽  
AndreiA. Khorobrykh ◽  
Norio Murata

The protective effect of 1 M glycinebetaine on thermal inactivation of photosynthetic oxygen evolution in isolated photosystem II membrane fragments from spinach is observed in CO2-free medium in both the presence and absence of added 2 mM bicarbonate. Conversely, the protective effect of 2 mM bicarbonate against thermoinactivation is seen in the absence as well as in the presence of 1 M glycinebetaine. The stabilizing effect of bicarbonate is also observed in thylakoid membranes from Synechococcus sp. PCC 7002 treated with 0.1% Triton X-100, and in unbroken spinach thylakoids. It is shown for the first time that bicarbonate protects the water-oxidizing complex against inactivation induced by pre-incubation of photosystem II membrane fragments (25°C) and thylakoids (40°C) at low pH (5.0–5.5) in non-bicarbonate-depleted medium. We conclude that the protective effects of glycinebetaine and bicarbonate are of a different nature; glycinebetaine acts as a non-specific, compatible, zwitterionic osmolyte while bicarbonate is considered an essential constituent of the water-oxidizing complex of photosystem II, important for its functioning and stabilization.


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.


2014 ◽  
Vol 16 (24) ◽  
pp. 11911-11923 ◽  
Author(s):  
H. Isobe ◽  
M. Shoji ◽  
S. Yamanaka ◽  
H. Mino ◽  
Y. Umena ◽  
...  

Broken-symmetry UB3LYP calculations have elucidated structural symmetry-breaking in the S1 and S3 states of the oxygen evolution complex (OEC) of photosystem II (PSII), providing the right (RO)- and left (LO)-opened structures.


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