Abstract
Alkylbenzyldimethylammonium chloride (ABDAC, zephirol) has been shown to improve the functioning of the photosynthetic apparatus of the filamentous cyanobacterium Oscillatoria chalybea (Bader, K. P. (1989) Biochim. Biophys. Acta 975, 399-402). This biocide exerts stimulatory effects on various electron transport reactions in Oscillatoria chalybea and chloroplasts from higher plants. By means of oxygen evolution measurements and of repetitive flash-induced absorption spectroscopy we were able to demonstrate an impact of the drug on the major complexes of photosynthetic membranes, i.e. the water splitting complex, photosystem II and photosystem I. Both, P 820 - and X 320 -absorption change signals were enhanced by the addition of ABDAC. Along with the quantitative analysis we investigated the relaxation kinetics of the signals and observed a substantial stabilization of the oxidized states of the respective redox components in the presence of the ammonium salt. Under appropriate conditions the relaxation kinetics of the absorption signals were significantly slowed down. ABDAC also affects photosystem I in Oscillatoria chalybea, but only under conditions, where a donor/acceptor system i.e. an isolated photosystem I reaction with photosystem II being disconnected was measured. Electron transport through the whole chain i.e. with water as the electron donor yielded no effect of the quaternary ammonium salt. It is suggested that this is due to an extremely bad linkage between the two photosystem, each of which, however, shows good reaction rates, when separately measured. The described interactions of the biocide with photosynthetic membranes are not restricted to Oscillatoria chalybea but are also observed with higher plant chloroplasts. In these systems, ABDAC enhances X 320 - and P 700 -signals to a comparable extent. In this case the P 700 -signal is stimulated in assays with electrons which are furnished from water which hints at good coupling between the two photosystems in our tobacco chloroplast preparations.
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Claims 8
Claim · model-written summary
ABDAC enhanced P820- and X320-absorption change signals in Oscillatoria chalybea.
- Taxon
- Oscillatoria chalybea
Phormidium chalybeume1 - Treatment
- addition of ABDACe0
- Outcome
- P 820 - and X 320 -absorption change signalse0
- Direction
- enhancede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Both, P 820 - and X 320 -absorption change signals were enhanced by the addition of ABDAC”
e1“This biocide exerts stimulatory effects on various electron transport reactions in Oscillatoria chalybea and chloroplasts from higher plants”
Claim · model-written summary
ABDAC significantly slowed the relaxation kinetics of the absorption signals under appropriate conditions.
- Taxon
- Oscillatoria chalybeaPhormidium chalybeume1
- Outcome
- relaxation kinetics of the absorption signalse0
- Direction
- slowed downe0
- Qualifier
- Under appropriate conditionse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Under appropriate conditions the relaxation kinetics of the absorption signals were significantly slowed down”
e1“This biocide exerts stimulatory effects on various electron transport reactions in Oscillatoria chalybea and chloroplasts from higher plants”
Claim · model-written summary
ABDAC affects photosystem I in Oscillatoria chalybea only when photosystem I is measured without photosystem II.
- Taxon
- Oscillatoria chalybeaPhormidium chalybeume1
- Outcome
- photosystem Ie0
- Qualifier
- only under conditions, where a donor/acceptor systeme0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“ABDAC also affects photosystem I in Oscillatoria chalybea, but only under conditions, where a donor/acceptor system”
e1“This biocide exerts stimulatory effects on various electron transport reactions in Oscillatoria chalybea and chloroplasts from higher plants”
Claim · model-written summary
ABDAC had no effect on electron transport through the whole chain with water as electron donor.
- Taxon
- Oscillatoria chalybeaPhormidium chalybeume1
- Treatment
- quaternary ammonium salte0
- Outcome
- electron transport through the whole chaine0
- Direction
- no effecte0
- Qualifier
- with water as the electron donore0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Electron transport through the whole chain i.e. with water as the electron donor yielded no effect of the quaternary ammonium salt”
e1“This biocide exerts stimulatory effects on various electron transport reactions in Oscillatoria chalybea and chloroplasts from higher plants”
Claim · model-written summary
ABDAC substantially stabilised the oxidised states of the redox components.
- Taxon
- Oscillatoria chalybeaPhormidium chalybeume1
- Treatment
- the ammonium salte0
- Outcome
- oxidized states of the respective redox componentse0
- Direction
- substantial stabilizatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“observed a substantial stabilization of the oxidized states of the respective redox components in the presence of the ammonium salt”
e1“This biocide exerts stimulatory effects on various electron transport reactions in Oscillatoria chalybea and chloroplasts from higher plants”
Claim · model-written summary
In higher plant chloroplasts ABDAC enhanced X320- and P700-signals to a comparable extent.
Verbatim
e0“In these systems, ABDAC enhances X 320 - and P 700 -signals to a comparable extent”
e2“The described interactions of the biocide with photosynthetic membranes are not restricted to Oscillatoria chalybea but are also observed with higher plant chloroplasts”
Claim · model-written summary
In tobacco chloroplasts the P700 signal was stimulated when electrons were furnished from water.
- Taxon
- tobacco
Nicotiana tabacume0 - Outcome
- P 700 -signale0
- Direction
- stimulatede0
- Qualifier
- electrons which are furnished from watere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In this case the P 700 -signal is stimulated in assays with electrons which are furnished from water which hints at good coupling between the two photosystems in our tobacco chloroplast preparations”
Claim · model-written summary
ABDAC showed an impact on the water splitting complex, photosystem II and photosystem I.
- Taxon
- Oscillatoria chalybeaPhormidium chalybeume1
- Outcome
- impact of the drug on the major complexese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“we were able to demonstrate an impact of the drug on the major complexes of photosynthetic membranes, i.e. the water splitting complex, photosystem II and photosystem I”
e1“This biocide exerts stimulatory effects on various electron transport reactions in Oscillatoria chalybea and chloroplasts from higher plants”