Interaction between photosynthetic and respiratory electron-transfer chains in the membranes of Anabaena variabilis |
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Authors: | F D Abdourashitova E L Barsky M V Gusev V D Samuilov |
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Institution: | (1) Biology Faculty, Moscow State University, V-234, GSP 119899 Moscow, USSR |
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Abstract: | The rate of CO2- and p-benzoquione-dependent photosynthetic O2 evolution by Anabaena variabilis cells remained unaltered and the rate of O2 uptake observed after switching off the light (endogenous respiration) was enhanced by a factor of 6–8 when the O2 concentration was increased from 200 to 400 M. Photosystem-I-linked O2 uptake and respiration of the cells incubated with ascorbate and N,N,N N -tetramethyl-p-phenylenediamine was not appreciable influenced by the O2 concentration. 2-Iodo-6-isopropyl-3-methyl-2 ,4,4 -trinitrodiphenyl ether, blocking electron transfer at the plastoquinone level, suppressed O2 evolution and had no influence on endogenous respiration. 2-n-Heptyl-4-hydroxyquinoline-N-oxide, an inhibitor of electron transfer between photosystems II and I, as well as the cytochrome-oxidase inhibitors N
3
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, CN- and NH2OH, caused a 35–50% retardation of endogenous respiration and blocked photosynthetic O2 evolution. The molar ratio of cytochromes b6, f, c-553, aa3 and photosystem-I reaction centers in the isolated membranes equalled approx. 2:1:2:0.7:2. It is inferred that endogenous respiration of A. variabilis cells is inhibited by the light-induced electron flow through both photosystems at the level of the plastoquinone-plastocyanin-oxidoreductase complex.Abbreviations DCMU
3-(3 ,4 -dichlorophenyl)-1,1-dimethylurea
- DNP-INT
2-iodo-6-isopropyl-3-methyl-2 ,4,4 -trinitrodiphenyl ether
- Hepes
4-(2-hydroxyethyl)-1-piperazine ethansulfonic acid
- TMPD
N,N,N N -tetramethyl-p-phenylenediamine |
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Keywords: | Anabaena Cyanobacteria Electron transport Photosynthesis and respiration Respiration and photosynthesis |
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