Adaptation of Photosynthetic CO2 and HCO-3 Accumulation by the Cyanobacterium Synechococcus PCC6301 to Growth at Different Inorganic Carbon Concentrations

Badger, Murray R.; Gallagher, Anne M.

doi:10.1071/pp9870189

Cited by 29 publications

(49 citation statements)

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“…At this stage, however, it must be considered 187 that HCO 3 may have a direct effect on reactions involved in 0 2 photoreduction. Interestingly, cyanobacteria accumulate Ci in the cytosol surrounding the thylakoids at concentrations ranging from 10 to 50 mM, which is far higher than in any other known photosynthetic system (Badger 1987, Miller et al 1990. It is thus important to note, that cyanobacteria appear to have a greater capacity for 0 2 photoreduction than higher plant chloroplasts (Badger 1985).…”

Section: Discussionmentioning

confidence: 99%

“…Two distinct possibilities can be suggested. Firstly, the stimulation may be related to the transport of Ci into the cells, a process which has been shown to require photosynthetically derived ATP (Badger 1987). In this case, the stimulation of 0 2 photoreduction would be due to the consumption of ATP by the transport system which would stimulate the capacity for linear electron flow to 02.…”

Section: Studies With Cyanobacterium Synechococcusmentioning

confidence: 99%

“…Cyanobacteria possess a CO 2 concentrating mechanism which allows them to optimise their photosynthetic efficiency with regard to inorganic carbon (Ci) utilisation from the external aquatic environment (Badger 1987, Miller et al 1990, Kaplan et al 1991, Badger and Price 1992. This mechanism is primarily dependent upon a Ci transport system which is most likely located on the plasmamembrane and uses energy derived from the thylakoid reactions of photosynthesis to drive the accumulation of HCO 3 within the cytosol of the cell.…”

Section: Introductionmentioning

confidence: 99%

“…This mechanism is primarily dependent upon a Ci transport system which is most likely located on the plasmamembrane and uses energy derived from the thylakoid reactions of photosynthesis to drive the accumulation of HCO 3 within the cytosol of the cell. This active accumulation of HCO 3 can lead to a 1000-10 000 fold accumulation of Ci within the cells and cytosolic HCO 3 pools which may range between 15 and 50 mM (Badger 1987, Miller et al 1990). …”

Section: Introductionmentioning

confidence: 99%

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Effects of inorganic carbon accumulation on photosynthetic oxygen reduction and cyclic electron flow in the cyanobacterium Synechococcus PCC7942

Badger

Schreiber

1993

Photosynth Res

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This paper examines the effect of inorganic carbon transport and accumulation in Synechococcus PCC7942 on fluorescence quenching, photosynthetic oxygen reduction and both linear and cyclic electron flow. The data presented support the previous findings of Miller et al. (1991) that the accumulation of Ci by the CO2 concentrating mechanism is able to stimulate oxygen photoreduction, particularly so when CO2 fixation is inhibited by PCR cycle inhibitors such as glycolaldehyde. This effect is found with both high and low-Ci grown cells, but the potential for oxygen photoreduction is about two-fold higher in low-Ci grown cells. This greater potential for O2 photoreduction is also correlated with a higher ability of low-Ci cells to photoreduce H2O2. Experiments with a mutant which transports Ci but does not accumulate it internally, indicates that the stimulation of O2 photoreduction appears to be a direct effect of the internal accumulation of Ci rather than from its participation in the transport process. In the absence of Ci, no specific partial reactions of photosynthetic electron transport appear to be inhibited, and the PS 1 acceptors PNDA and MV as well as the PS 2 acceptor DMQ can all run electron transport at levels approaching those during active CO2 fixation. Measurements of P700(+) show that when the cells are depleted of Ci during photosynthesis, P700 becomes more oxidised. This indicates that the resupply of electrons from the intersystem chain is relatively more restricted under conditions of Ci limitation than is the availability of PS 1 electron acceptors. It is proposed that the accumulated Ci pool can directly stimulate the ability of O2 to act as a PS 1 acceptor and that the ability of PS 1 acceptors, such as O2, to relieve restrictions on intersystem electron transfer is perhaps a result of a reduction in cyclic electron flow and a subsequent increase in the oxidation state of the plastoquinone pool.

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Section: Discussionmentioning

confidence: 99%

Section: Studies With Cyanobacterium Synechococcusmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effects of inorganic carbon accumulation on photosynthetic oxygen reduction and cyclic electron flow in the cyanobacterium Synechococcus PCC7942

Badger

Schreiber

1993

Photosynth Res

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“…A number of methods have been applied in an attempt to discriminate between transport of CO2 and HCO~. These methods include a silicone-fluid-filtering centrifugation technique (Badger and Andrews 1982;Volokita et al 1984;Miller and Canvin 1985;Price and Badger 1989a, b;Espie and Kandasamy 1994), measurements of COz fixation or Oz evolution under steady-state photosynthesis at CO//HCO~ disequilibrium (Badger and Andrews 1982;Miller 1985;Badger and Gallagher 1987;Espie et al 1988), chlorophyll a fluorescence (Miller et al 1991;Crotty et al 1994;Espie and Kandasamy 1994), measurements of photosynthesis at various external pH values (Badger and Andrews 1982;Price and Badger 1989b) and mass-spectrometric analysis of COz and 02 gas exchange (Badger and Andrews 1982;Miller et al t988).…”

Section: Introductionmentioning

confidence: 99%

Characterisation of carbon dioxide and bicarbonate transport during steady-state photosynthesis in the marine cyanobacterium Synechococcus strain PCC7002

Sültemeyer

Price

et al. 1995

Planta

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Net 02 evolution, gross CO2 uptake and net HCO~ uptake during steady-state photosynthesis were investigated by a recently developed mass-spectrometric technique for disequilibrium flux analysis with cells of the marine cyanobacterium Synechococcus PCC7002 grown at different CO2 concentrations. Regardless of the CO2 concentration during growth, all cells had the capacity to transport both CO2 and HCO3; however, the activity of HCO~ transport was more than twofold higher than CO2 transport even in cyanobacteria grown at high concentration) of inorganic carbon (Ci = CO2 + HCO~-. In low-Ci cells, the affinities of CO2 and HCO~ transport for their substrates were about 5 (CO2 uptake) and 10 (HCO3 uptake) times higher than in high-Ci cells, while air-grown cells formed an intermediate state. For the same cells, the intracellular accumulated C~ pool reached 18, 32 and 55 mM in high-Ci, air-grown and low-Ci cells, respectively, when measured at 1 mM external Ci. Photosynthetic 02 evolution, maximal CO2 and HCO3 transport activities, and consequently their relative contribution to photosynthesis, were largely unaffected by the CO2 provided during growth. When the cells were adapted to freshwater medium, results similar to those for artificial seawater were obtained for all CO2 concentrations. Transport studies with high-Ci cells revealed that CO2 and HCO~ uptake were equally inhibited when CO2 fixation was reduced by the addition of glycolaldehyde. In contrast, in low-C~ cells steady-state CO2 transport was preferably reduced by the same inhibitor. The inhibitor of carbonic anhydrase ethoxyzolamide inhibited both CO2 and HCO3 uptake as well as 02 evolution in both cell types. In high-Ci cells, the degree of inhibition was similar Abbreviations: Chl = chlorophyll: Ci = inorganic carbon (CO 2 + HCO~); CA = carbonic anhydrase; CCM = CO2-concentrating mechanism; EZA = ethoxyzolamide; GA = glycolaldehyde; KI/2 = concentration required for half-maximal response; Rubisco = ributose-1,5,-bisphosphate earboxylase-oxygenase for HCO~ transport and 02 evolution with 50% inhibition occurring at around 1 mM ethoxyzolamide. However, the uptake of CO2 was much more sensitive to the inhibitor than HCOf transport, with an apparent Is0 value of around 250 ~M ethoxyzolamide for CO2 uptake. The implications of our results are discussed with respect to Ci utilisation in the marine Synechococcus strain.

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Vascular Plants as Epiphytes

Lüttge¹

1989

Ecological Studies

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Adaptation of Photosynthetic CO2 and HCO-3 Accumulation by the Cyanobacterium Synechococcus PCC6301 to Growth at Different Inorganic Carbon Concentrations

Cited by 29 publications

References 0 publications

Effects of inorganic carbon accumulation on photosynthetic oxygen reduction and cyclic electron flow in the cyanobacterium Synechococcus PCC7942

Effects of inorganic carbon accumulation on photosynthetic oxygen reduction and cyclic electron flow in the cyanobacterium Synechococcus PCC7942

Characterisation of carbon dioxide and bicarbonate transport during steady-state photosynthesis in the marine cyanobacterium Synechococcus strain PCC7002

Vascular Plants as Epiphytes

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