Photoreduction of silicomolybdate in chloroplasts by agents accelerating the deactivation reactions of the water‐oxidizing system

Самуилов, В. Д.; Barsky, E. L.; Gubanova, O. N.; Klimov, Vyacheslav V.; Kozlov, Yury N.

doi:10.1016/0014-5793(94)01309-o

Cited by 7 publications

(5 citation statements)

References 25 publications

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“…Effect of CCCP on the PSII Photochemical Activity during Illumination. It was reported that protonophoric uncouplers such as CCCP can accelerate the deactivation reactions of the water splitting system (ADRY reagent) in the PSII reaction center and inhibit O 2 evolution (22, 23). To test the hypothesis that the inhibition of PSII photoevolution of O 2 by CCCP contributes to maintaining the anaerobiosis and therefore sustained hydrogen production in the light, the effect of CCCP on the PSII photochemical activity was measured.…”

Section: Resultsmentioning

confidence: 99%

Role of Carbonyl Cyanide m-Chlorophenylhydrazone in Enhancing Photobiological Hydrogen Production by Marine Green Alga Platymonas subcordiformis

Ran

Jin

et al. 2006

Biotechnol. Prog.

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We demonstrated that a significant volume of H(2) gas could be photobiologically produced by a marine green alga Platymonas subcordiformis when an uncoupler of photophosphorylation, carbonyl cyanide m-chlorophenylhydrazone (CCCP), was added after 32 h of anaerobic dark incubation, whereas a negligible volume of H(2) gas was produced without CCCP. The role of CCCP in enhancing photobiological H(2) production was delineated. CCCP as an ADRY agent (agent accelerating the deactivation reactions of water-splitting enzyme system Y) rapidly inhibited the photosystem II (PSII) activity of P. subcordiformis cells, resulting in a markedly decline in the coupled oxygen evolution. The mitochondrial oxidative respiration was only slightly inactivated by CCCP, which depleted O(2) in the light. As a result, anaerobiosis during the stage of photobiological H(2) evolution was established, preventing severe O(2) inactivation of the reversible hydrogenase in P. subcordiformis. The uncoupling effect of CCCP accelerates electron transfer from water due to a disruption of the proton motive force and release of DeltapH across the thylakoid membrane and thus enhances the accessibility of electron and H(+) to hydrogenase. The electrons for hydrogen photoevolution are mainly from the photolysis of water (90%). Upon the addition of CCCP, Chl a/b ratio increased, which implies a decrease in the light-harvesting PSII antennae or an increase in PSII/PSI ratio, possibly resulting in higher efficiency of utilization of light energy. The enhancement of H(2) evolution by the addition of CCCP is mostly due to the combination of the above three mechanisms. However, the disruption of the proton gradient across the thylakoid membrane may prevent a sustained photobiological H(2) evolution due to a shortfall of ATP generation essential for the maintenance and repair functions of the cells.

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Section: Resultsmentioning

confidence: 99%

Role of Carbonyl Cyanide m-Chlorophenylhydrazone in Enhancing Photobiological Hydrogen Production by Marine Green Alga Platymonas subcordiformis

Ran

Jin

et al. 2006

Biotechnol. Prog.

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“…CCCP also dissipated the proton motive force across the mitochondrial membrane. This dissipation resulted in the cessation of ATP production and increased ADP availability, thereby stimulating respiration [13].The property of CCCP as an ADRY agent (agent accelerating of the deactivation reactions of the water-splitting en-zyme system Y) enables it to accelerate the deactivation reactions in the water-splitting enzyme system Y [14]. Therefore, anaerobic conditions can be effectively established and maintained by the addition of CCCP.…”

Section: Effects Of Cccp and S-deprivation On H 2 Photoproductionmentioning

confidence: 99%

“…CCCP can accelerate the deactivation reaction of the watersplitting system in the PSII reaction center, leading to the inhibition of O 2 photo-evolution [14]. PSII plays an important role in the PSII-dependent H 2 production pathway, where water photolysis is the major source of electrons [15,16].…”

Section: Effect Of Cccp On Psii Activity During H 2 Productionmentioning

confidence: 99%

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Characterization of H2 photoproduction by a new marine green alga, Platymonas helgolandica var. tsingtaoensis

et al. 2012

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A significant improvement in H 2 photoproduction was observed in the marine green alga Platymonas helgolandica var. tsingtaoensis in the presence of the uncoupler carbonyl cyanide m-chlorophenylhydrazone (CCCP). The addition of 15 lM CCCP to algal cultures led to a 260-fold increase in H 2 production compared with a negligible volume of H 2 gas produced without CCCP. The photosystem (PS) II photochemical activity was shown to be completely inhibited in the presence of CCCP under illumination. The added herbicide 3-(3,4-dichlorophenyl)-1, 1-dimethylurea further resulted in a twofold increase in H 2 photoproduction in the CCCP-treated cultures. These results demonstrated the absence of PSII-dependent pathway of H 2 photoproduction. H 2 production essentially depends on electrons donated to the hydrogenase by the endogenous substrate catabolism in CCCP-treated P. helgolandica var. tsingtaoensis. An analysis of the O 2 -tolerance of the hydrogenase of P. helgolandica var. tsingtaoensis suggested that this enzyme may belong to the class [FeFe]-hydrogenase.

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“…Carbonyl cyanide m-chlorophenyl hydrazone (CCCP) has long been recognized as a photosystem II inhibitor of cyanobacteria and green algae [10]. CCCP has been shown to inhibit the photochemical activity of PSII under illumination in cyanobacteria Synechocystis sp.…”

Section: Introductionmentioning

confidence: 99%

Effects of the Photosystem II Inhibitors CCCP and DCMU on Hydrogen Production by the Unicellular Halotolerant CyanobacteriumAphanothece halophytica

Pansook

Incharoensakdi

Phunpruch

2019

The Scientific World Journal

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The unicellular halotolerant cyanobacterium Aphanothece halophytica is a potential dark fermentative producer of molecular hydrogen (H2) that produces very little H2 under illumination. One factor limiting the H2 photoproduction of this cyanobacterium is an inhibition of bidirectional hydrogenase activity by oxygen (O2) obtained from splitting water molecules via photosystem II activity. The present study aimed to investigate the effects of the photosystem II inhibitors carbonyl cyanide m-chlorophenyl hydrazone (CCCP) and 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) on H2 production of A. halophytica under light and dark conditions and on photosynthetic and respiratory activities. The results showed that A. halophytica treated with CCCP and DCMU produced H2 at three to five times the rate of untreated cells, when exposed to light. The highest H2 photoproduction rates, 2.26 ± 0.24 and 3.63 ± 0.26 μmol H2 g−1 dry weight h−1, were found in cells treated with 0.5 μM CCCP and 50 μM DCMU, respectively. Without inhibitor treatment, A. halophytica incubated in the dark showed a significant increase in H2 production compared with cells that were incubated in the light. Only CCCP treatment increased H2 production of A. halophytica during dark incubation, because CCCP functions as an uncoupling agent of oxidative phosphorylation. The highest dark fermentative H2 production rate of 39.50 ± 2.13 μmol H2 g−1 dry weight h−1 was found in cells treated with 0.5 μM CCCP after 2 h of dark incubation. Under illumination, CCCP and DCMU inhibited chlorophyll fluorescence, resulting in a low level of O2, which promoted bidirectional hydrogenase activity in A. halophytica cells. In addition, only CCCP enhanced the respiration rate, further reducing the O2 level. In contrast, DCMU reduced the respiration rate in A. halophytica.

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Photoreduction of silicomolybdate in chloroplasts by agents accelerating the deactivation reactions of the water‐oxidizing system

Cited by 7 publications

References 25 publications

Role of Carbonyl Cyanide m-Chlorophenylhydrazone in Enhancing Photobiological Hydrogen Production by Marine Green Alga Platymonas subcordiformis

Role of Carbonyl Cyanide m-Chlorophenylhydrazone in Enhancing Photobiological Hydrogen Production by Marine Green Alga Platymonas subcordiformis

Characterization of H2 photoproduction by a new marine green alga, Platymonas helgolandica var. tsingtaoensis

Effects of the Photosystem II Inhibitors CCCP and DCMU on Hydrogen Production by the Unicellular Halotolerant CyanobacteriumAphanothece halophytica

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