A strain of Synechocystis sp. PCC 6803 without photosynthetic oxygen evolution and respiratory oxygen consumption: implications for the study of cyclic photosynthetic electron transport

Planta ◽  
2001 ◽  
Vol 214 (1) ◽  
pp. 46-56 ◽  
Author(s):  
Crispin A. Howitt ◽  
Jason W. Cooley ◽  
Joseph T. Wiskich ◽  
Wim F. Vermaas
Keyword(s):  
Oxygen Consumption ◽  
Electron Transport ◽  
Oxygen Evolution ◽  
Photosynthetic Electron Transport ◽  
Photosynthetic Oxygen Evolution ◽  
Photosynthetic Oxygen ◽  
Synechocystis Sp ◽  
Pcc 6803

scholarly journals TIP family aquaporins play role in chloroplast osmoregulation and photosynthesis

2020 ◽  
Author(s):  
Azeez Beebo ◽  
Ahmad Zia ◽  
Christopher R. Kinzel ◽  
Andrei Herdean ◽  
Karim Bouhidel ◽  
...  
Keyword(s):  
Electron Transport ◽  
Oxygen Evolution ◽  
Photosynthetic Electron Transport ◽  
Chloroplast Envelope ◽  
Photosynthetic Oxygen Evolution ◽  
Wild Type ◽  
Thylakoid Lumen ◽  
Photosynthetic Oxygen ◽  
Osmotic Treatment ◽  
Envelope Membranes

SUMMARYPhotosynthetic oxygen evolution by photosystem II requires water supply into the chloroplast to reach the thylakoid lumen. A rapid water flow is also required into the chloroplast for optimal oxygen evolution and to overcome osmotic stress. The mechanisms governing water transport in chloroplasts are largely unexplored. Previous proteomics indicated the presence of three aquaporins from the tonoplast intrinsic protein (TIP) family, TIP1;1, TIP1;2 and TIP2;1, in chloroplast membranes of Arabidopsis thaliana. Here we revisited their location and studied their role in chloroplasts. Localization experiments indicated that TIP2;1 resides in the thylakoid, whereas TIP1;2 is present in both thylakoid and envelope membranes. Mutants lacking TIP1;2 and/or TIP2;1 did not display a macroscopic phenotype when grown under standard conditions. The mutant chloroplasts and thylakoids underwent less volume changes than the corresponding wild type preparations upon osmotic treatment and in the light. Significantly reduced rates of photosynthetic electron transport were obtained in the mutant leaves, with implications on the CO2 fixation rates. However, electron transport rates did not significantly differ between mutants and wild type when isolated thylakoids were examined. Less acidification of the thylakoid lumen was measured in mutants thylakoids, resulting in a slower induction of delta pH-dependent photoprotective mechanisms. These results identify TIP1;2 and TIP2;1 as chloroplast proteins and highlight their importance for osmoregulation and optimal photosynthesis. A third aquaporin, TIP1;1, is present in the chloroplast envelope, and may play role in photosynthesis under excessive light conditions, as based on the weak photosynthetic phenotype of its mutant.

Influence of Bleaching Herbicides on Chlorophyll and Carotenoids

1979 ◽  
Vol 34 (11) ◽  
pp. 1047-1051 ◽  
Author(s):  
Karl-Josef Kunert ◽  
Peter Böger
Keyword(s):  
Electron Transport ◽  
Oxygen Evolution ◽  
Green Alga ◽  
Photosynthetic Electron Transport ◽  
Pigment Content ◽  
Photosynthetic Oxygen Evolution ◽  
Direct Inhibition ◽  
Scenedesmus Acutus ◽  
Photosynthetic Oxygen ◽  
Chlorophyll Formation

Abstract Over 24 and 48 hour cultivation periods the influence of SAN 9789 (norflurazon), EMD-IT 5914 (difunon) and fluridone on growth, photosynthetic oxygen evolution and pigment content of the green alga Scenedesmus acutus was determined. Four effects were observed: a) Both carotenoid and chlorophyll formation were inhibited. b) Carotenoids were destroyed in the presence of air, but not nitrogen. The level of chlorophyll, however, did not change. c) β- (and α-) carotene was markedly decreased in the presence of oxygen. d) Photosynthetic oxygen evolution was decreased with the disappearance of carotenoids. These effects, which are accompanied by reduced growth, are believed to represent primary herbicidal modes of action. The decrease of oxygen evolution is not due to a direct inhibition of photosynthetic electron transport by the herbicides applied.

scholarly journals Remodeling of photosynthetic electron transport in Synechocystis sp. PCC 6803 for future hydrogen production from water

2020 ◽  
Vol 1861 (8) ◽  
pp. 148208
Author(s):  
Daniela Kannchen ◽  
Jure Zabret ◽  
Regina Oworah-Nkruma ◽  
Nina Dyczmons-Nowaczyk ◽  
Katrin Wiegand ◽  
...  
Keyword(s):  
Electron Transport ◽  
Hydrogen Production ◽  
Photosynthetic Electron Transport ◽  
Synechocystis Sp ◽  
Pcc 6803

Blue Light-Enhanced Photosynthetic Oxygen Evolution from Liposome-Bound Photosystem II Particles; Possible Role of the Xanthophyll Cycle in the Regulation of Cyclic Electron Flow Around Photosystem II?

1995 ◽  
Vol 50 (1-2) ◽  
pp. 61-68 ◽  
Author(s):  
W. I. Gruszecki ◽  
K. Strzałka ◽  
A. Radunz ◽  
J. Kruk ◽  
G. H. Schmid
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Oxygen Evolution ◽  
Xanthophyll Cycle ◽  
Red Light ◽  
Photosynthetic Oxygen Evolution ◽  
Reaction Centre ◽  
Ps Ii ◽  
Photosynthetic Oxygen ◽  
Β Carotene

Abstract Light-driven electron transport in liposome-bound photosystem II (PS-II) particles be­tween water and ferricyanide was monitored by bare platinum electrode oxymetry. The modi­fication of the experimental system with the exogenous quinones α-tocopherol quinone ( α-TQ) or plastoquinone (PQ) resulted in a pronounced effect on photosynthetic oxygen evolution. The presence of α-tocopherolquinone ( α-TQ) in PS-II samples decreased the rate of red light-induced oxygen evolution but increased the rate of green light-induced oxygen evolution. Blue light applied to the assay system in which oxygen evolution was saturated by red light resulted in a further increase of the oxygen signal. These findings are interpreted in terms of a cyclic electron transport around PS-II, regulated by an excitation state of β-carotene in the reaction centre of PS-II. A mechanism is postulated according to which energetic coupling of β-carotene in the reaction centre of PS-II and that of other antenna carotenoid pigments is regulated by the portion of the xanthophyll violaxanthin, which is under control of the xanthophyll cycle.

Dependence of the Flash-Induced Oxygen Evolution Pattern on the Chemically and Far Red Light-Modulated Redox Condition in Cyanobacterial Photosynthetic Electron Transport

2003 ◽  
Vol 58 (1-2) ◽  
pp. 93-102 ◽  
Author(s):  
Susanne Spiegel ◽  
Klaus P. Bader
Keyword(s):  
Oxygen Evolution ◽  
Redox Condition ◽  
Photosynthetic Oxygen Evolution ◽  
Background Illumination ◽  
Relaxation Kinetics ◽  
Oscillatoria Chalybea ◽  
Synechococcus Sp ◽  
Pcc 7942 ◽  
Synechocystis Sp ◽  
Pcc 6803

Flash-induced photosynthetic oxygen evolution was measured in cells and thylakoid preparations from the coccoid cyanobacteria Synechocystis sp. PCC 6803 and Synechococcus sp. PCC 7942 and from the filamentous cyanobacterium Oscillatoria chalybea. The resulting characteristic flash patterns from these cyanobacteria can be chemically altered by addition of exogenously added substances like CCCP, DCPiP and inorganic salts. Potassium chloride, manganese sulfate and calcium chloride affected the sequences by specific increases in the flash yield and/or effects on the transition parameters. Chloride appeared to exert the strongest stimulatory effect on the oxygen yield. In comparison to chloride, both manganese and calcium did not significantly stimulate the flash amplitudes as such, but improved the functioning of the oxygen evolving complex by decreasing the miss parameter α. Particular effects were observed with respect to the time constants of the relaxation kinetics of the first two flash signals Y1/Y2 of the cyanobacterial patterns. In the presence of the investigated chemicals the amplitudes of the first two flash signals (Y2 in particular) were increased and the relaxation kinetics were enhanced so that the time constant became about identical to the conditions of steady state oxygen flash amplitudes. The results provide further evidence against a possible participation of either PS I or respiratory processes to Y1/Y2 of cyanobacterial flash patterns. Dramatic effects were observed when protoplasts from Oscillatoria chalybea or cells from Synechocystis sp. PCC 6803 and Synechococcus sp. PCC 7942 were exposed to weak far red background illumination. Under these conditions, Y2 (and to a smaller extent Y1) of otherwise unchanged flash sequences were specifically modified. Y2 was substantially increased and again the relaxation kinetics were accelerated making the signal indistinguishable from a Yss signal. From the mathematical fit of the sequences we conclude that S2 contributes to 10-20% of the S-state distribution (in comparison to 0% in the control). Thus, far red background illumination might represent a valuable means for photosynthetic investigations where high amounts of S2 are required like e.g. EPR measurements. In such experiments the corresponding EPR signals appeared substantially enhanced following far red preillumination (Ahrling and Bader, unpublished observations). Our results clearly show that the ‚controversial results‘ from parts of the literature suggesting the participation of different mechanisms (net oxygen evolution, inhibited uptake processes etc.) are not required to explain the flash-induced oxygen evolution in cyanobacteria: the seemingly ‚incompatible‘ conditions and conformations can be perfectly interconverted by different modulation techniques (chemicals, far red) of the respective redox condition within the water oxidation complex of photosynthesis

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