Mode of Inhibition of Photosynthetic Electron Transport by Substituted Diphenylethers

1981 ◽  
Vol 36 (9-10) ◽  
pp. 848-852 ◽  
Author(s):  
W. Draber ◽  
H. J. Knops ◽  
A. Trebst
Keyword(s):  
Electron Transport ◽  
Electron Flow ◽  
Photosynthetic Electron Transport ◽  
Thylakoid Membranes ◽  
Photosynthetic Electron Flow ◽  
Spinach Chloroplasts

Abstract Several substituted diphenylethers were found to be effective inhibitors of photosynthetic electron flow in isolated thylakoid membranes from spinach chloroplasts. T heir site of inhibition was localized with artificial acceptor and donor systems. The phenylether of an alkyl substituted nitrophenol is prim arely inhibiting electron flow after plastoquinone function whereas a dinitro-phenylether of a phenyl substituted nitrophenol is inhibiting before plastoquinone function. Therefore certain diphenylethers interfere with plastoquinone function at the oxidation or reduction site, depending on the substitution.

Interaction of Photosystem II Herbicides with Bicarbonate and Formate in Their Effects on Photosynthetic Electron Flow

1984 ◽  
Vol 39 (5) ◽  
pp. 374-377 ◽  
Author(s):  
J. J. S. van Rensen
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Electron Flow ◽  
Photosynthetic Electron Transport ◽  
Hill Reaction ◽  
Amaranthus Hybridus ◽  
Apparent Affinity ◽  
Photosynthetic Electron Flow ◽  
Different Characteristics ◽  
The Hill

The reactivation of the Hill reaction in CO2-depleted broken chloroplasts by various concentrations of bicarbonate was measured in the absence and in the presence of photosystem II herbicides. It appears that these herbicides decrease the apparent affinity of the thylakoid membrane for bicarbonate. Different characteristics of bicarbonate binding were observed in chloroplasts of triazine-resistant Amaranthus hybridus compared to the triazine-sensitive biotype. It is concluded that photosystem II herbicides, bicarbonate and formate interact with each other in their binding to the Qв-protein and their interference with photosynthetic electron transport.

Inhibition of Photosynthetic Electron Transport by Azaphenanthrenes

1974 ◽  
Vol 29 (9-10) ◽  
pp. 545-551 ◽  
Author(s):  
Walter Oettmeier ◽  
Rolf Grewe
Keyword(s):  
Electron Transport ◽  
Mechanism Of Action ◽  
Inhibitory Activity ◽  
Electron Flow ◽  
Photosynthetic Electron Transport ◽  
Iron Complexes ◽  
Lower Activity ◽  
Photosynthetic Electron Flow ◽  
Isolated Chloroplasts ◽  
Insight Into

Abstract Various mono-and diazaphenanthrenes were prepared and assayed for their activity as inhibi­tors of photosynthetic electron flow in isolated chloroplasts in order to get more insight into the mechanism of action of the well known inhibitor o-phenanthroline = 1,10-diazaphenanthrene. The results show that 1-, 4-and 5-azaphenanthrene are only slightly less active than 1,10-diazaphen-anthrene. In the case of the different diazaphenanthrenes, 1,4-, 1,7-and 5,6-diazaphenanthrene exhibited somewhat lower activity than 1,10-diaphenanthrene, whereas 2,9-and 4,7-diazaphen-anthrene were completely inactive. Substitution at C-atoms of 1,10-diazaphenanthrene leads to an increase in activity in the case of the 4-and 7-position, regardless of electropositive or electro­ negative substituents, whereas substitution at the 2-, 3-, 5-, 6-, 8-and 9-position leads to a de­ creased activity. The ability of 1,10-diazaphenanthrene to form iron complexes seems to be of little relevance to the inhibitory activity on photosynthetic electron transport. This follows also from the fact that other strong iron complexing agens, like 2.2'-bipyridine or 8-hydroxyquinoline, are not inhibitory

The Inhibition of Photosynthetic Light Reactions by Halogenated Naphthoquinones

1981 ◽  
Vol 36 (7-8) ◽  
pp. 645-655 ◽  
Author(s):  
Klaus Pfister ◽  
Hartmut K. Lichtenthaler ◽  
Günther Burger ◽  
Hans Musso ◽  
Manuel Zahn
Keyword(s):  
Chlorophyll Fluorescence ◽  
Electron Transport ◽  
Binding Site ◽  
Chlorophyll A ◽  
Electron Flow ◽  
Photosynthetic Electron Transport ◽  
Ps Ii ◽  
Photosynthetic Electron Flow ◽  
A Site ◽  
Fluorescence Transients

Abstract Halogenated naphthoquinones act as inhibitors of photosynthetic electron flow. I50 concentra­ tion for inhibition of methylviologen reduction were found to range between 2 × 10-5 m to 2 × 10-6 M. Comparing their effects on several partial reactions of electron flow, the inhibition site of the naphthoquinones was found to be at the reducing site of PS II. Studies of fluorescence transients in presence of halogenated naphthoquinones give further evidence for a site action similar to that of diuron and different to that of DBMIB. All naphthoquinones act as quenchers of chlorophyll fluorescence with pure chlorophyll a, and with much higher efficiency in green algae and chloroplasts. It is concluded, that the halogenated naphthoquinones act similar to PS II-inhibitors like diuron, but do not share a common binding site at the PS II-complex. Implications of a possible involvement of phylloquinone K 1 in photosynthetic electron transport are discussed. The synthesis of 2-chloro-as well as 2-bromo-3-isopropyl-1,4-naphthoquinone is described.

scholarly journals Regulation of photosynthetic electron flow on dark to light transition by ferredoxin:NADP(H) oxidoreductase interactions

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Manuela Kramer ◽  
Melvin Rodriguez-Heredia ◽  
Francesco Saccon ◽  
Laura Mosebach ◽  
Manuel Twachtmann ◽  
...  
Keyword(s):  
Electron Transport ◽  
Electron Flow ◽  
Carbon Assimilation ◽  
Photosynthetic Electron Transport ◽  
Immunogold Labelling ◽  
Free Radical Damage ◽  
Transport Pathways ◽  
Photosynthetic Electron Flow ◽  
Radical Damage

During photosynthesis, electron transport is necessary for carbon assimilation and must be regulated to minimize free radical damage. There is a longstanding controversy over the role of a critical enzyme in this process (ferredoxin:NADP(H) oxidoreductase, or FNR), and in particular its location within chloroplasts. Here we use immunogold labelling to prove that FNR previously assigned as soluble is in fact membrane associated. We combined this technique with a genetic approach in the model plant Arabidopsis to show that the distribution of this enzyme between different membrane regions depends on its interaction with specific tether proteins. We further demonstrate a correlation between the interaction of FNR with different proteins and the activity of alternative photosynthetic electron transport pathways. This supports a role for FNR location in regulating photosynthetic electron flow during the transition from dark to light.

Die Wirkung 2.3-substituierter Naphthochinone auf einzellige Algen und isolierte Spinatchloroplasten/ The Effect of 2,3-Substituted Naphthoquinones on Unicellular Algae and Isolated Spinach Chloroplasts

1979 ◽  
Vol 34 (11) ◽  
pp. 961-963 ◽  
Author(s):  
Klaus Bauer ◽  
Helmu Kodier
Keyword(s):  
Electron Transport ◽  
Dark Respiration ◽  
Electron Flow ◽  
Photosynthetic Electron Transport ◽  
Flow Mode ◽  
Ps Ii ◽  
Spinach Chloroplasts ◽  
Ps I ◽  
Low Concentrations ◽  
Strong Stimulation

Abstract Short term effects of 2-(C-dichloro-acetylamino)-3-chloro-1,4-naphthoquinone (Hoe 13465, quinonamid*) and 2-amino-3-chloro-1,4-naphthoquinone (Hoe 17399, 06K-quinone) on cell suspensions of Chlorella vulgaris, Anabaena flos aquae, Porphyridium cruentum, and on isolated spinach chloroplasts were studied. The results clearly show that both substances inhibit the photosynthetic O2 production of algal suspensions as well as the electron transport of PS II in spinach chloroplasts. PS I is not inhibited by the action of the two algicides. At low concentrations quinonamid acts as a photosynthetic electron transport blocker, whereas Hoe 17399 is a weak inhibitor of photosynthetic electron flow. Mode of action of the two naphthoquinones is discussed. Both naphthoquinone derivatives can operate as an electron acceptor for PS I at low concentra­tions (10-5-10-6м). In addition there is observed a strong stimulation of dark respiration in algal cells induced by both of the compounds, Hoe 17399 causes a much higher stimulation rate than quinonamid does.

Inhibitors of Photosynthetic Electron Transport. The Properties of Diazidodialkylbenzoquinones

1979 ◽  
Vol 34 (5-6) ◽  
pp. 490-492 ◽  
Author(s):  
Hagan Bayley
Keyword(s):  
Electron Transport ◽  
Membrane Proteins ◽  
Electron Flow ◽  
Photosynthetic Electron Transport ◽  
Spinach Chloroplasts ◽  
High Concentrations

Abstract The potential photoaffinity reagents 2,5-diazido-3-methyl-6-isopropyl-1,4-benzoquinone (DAZMIB) and 2,5-diazido-3,6-dimethyl-1,4-benzoquinone (DAZDMQ), which are analogs of the well-known inhibitor 2,5-dibromo-3-methyl-6-isopropyl-1,4-benzoquinone (DBMIB), block photosynthetic electron transport in spinach chloroplasts. On irradiation, at relatively high concentrations, DAZMIB inhibits electron flow irrevers­ibly. However, when [3H] DAZDMQ was photolyzed with chloroplasts, no labeling of the membrane proteins was ob­ served. Rearrangements of the nitrenes derived from the oxidized or reduced azidoquinones that might account for this behaviour are discussed.

Rewiring photosynthesis: a photosystem I-hydrogenase chimera that makes H2in vivo

2020 ◽  
Vol 13 (9) ◽  
pp. 2903-2914 ◽  
Author(s):  
Andrey Kanygin ◽  
Yuval Milrad ◽  
Chandrasekhar Thummala ◽  
Kiera Reifschneider ◽  
Patricia Baker ◽  
...  
Keyword(s):  
Electron Transport ◽  
Hydrogen Production ◽  
Photosystem I ◽  
Electron Transport Chain ◽  
Electron Flow ◽  
Photosynthetic Electron Transport ◽  
Photosynthetic Electron Transport Chain ◽  
Transport Chain

Photosystem I-hydrogenase chimera intercepts electron flow directly from the photosynthetic electron transport chain and directs it to hydrogen production.

Inhibition by Tetranitromethane of Photosynthetic Electron Transport from Water to Photosystem II in Chloroplasts

1980 ◽  
Vol 35 (3-4) ◽  
pp. 293-297 ◽  
Author(s):  
P. V. Sane ◽  
Udo Johanningmeier
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Electron Flow ◽  
Ph Dependence ◽  
Photosynthetic Electron Transport ◽  
Donor Side ◽  
Ps Ii ◽  
Diphenyl Carbazide ◽  
Low Concentrations ◽  
Sh Group

Abstract Low concentrations (10 µM) of tetranitromethane inhibit noncyclic electron transport in spinach chloroplasts. A study of different partial electron transport reactions shows that tetranitromethane primarily interferes with the electron flow from water to PS II. At higher concentrations the oxidation of plastohydroquinone is also inhibited. Because diphenyl carbazide but not Mn2+ ions can donate electrons efficiently to PS II in the presence of tetranitromethane it is suggested that it blocks the donor side of PS II prior to donation of electrons by diphenyl carbazide. The pH dependence of the inhibition by this protein modifying reagent may indicate that a functional-SH group is essential for a protein, which mediates electron transport between the water splitting complex and the reaction center of PS II.

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