The Relationship between Ribulose Bisphosphate Concentration, Dissolved Inorganic Carbon (DIC) Transport and DIC-Limited Photosynthesis in the Cyanobacterium <i>Synechococcus leopoliensis</i> Grown at Different Concentrations of Inorganic Carbon

Mayo, William P.; Elrifi, Ivor R.; Turpin, David H.

doi:10.1104/pp.90.2.720

Cited by 29 publications

(20 citation statements)

References 27 publications

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“…Raising the external Q concentration resulted in decreasing the internal RuBP level, in agreement with the results of Mayo et al (1989). At Q concentrations where the photosynthetic rate was maximal, the internal RuBP pool fell below the concentration of Rubisco binding sites.…”

Section: Resultssupporting

confidence: 87%

“…In both types of cells, the highest level of RuBP was observed near the Q concentration at which the half-maximium rate of photosynthesis was reached. The highest level of RuBP detected in wild-type cells that were exposed to 0.1 mM Q (0.8 nmol/fig Chl) was similar to that determined in high-Qgrown Synechococcus leopoliensis (Mayo et al, 1989). The highest level of RuBP in EK6, in the presence of 8 mM Q, was about 50% lower than the highest level in the wild type.…”

Section: Resultssupporting

confidence: 73%

“…4) is within the range determined by Mayo et al (1989) in S. leopoliensis. However, in S. leopoliensis t h e pool size of RuBP i n high-Ci-grown cells d i d not, as here, fall below the concentration of Rubisco binding sites (Mayo e t al., 1989).…”

Section: Dlscusslonsupporting

confidence: 73%

“…Furthermore, the absence of a lag period in mutant cells exposed to high CO, (Fig. 3A) Berry, 1988; Mayo et al, 1989). Figure 4 presents the results of experiments where the steady-state rates of photosynthetic oxygen evolution and the size of the internal RuBP pools were determined as a function of the extracellular Q concentration.…”

Section: Resultsmentioning

confidence: 98%

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Low Activation State of Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase in Carboxysome-Defective Synechococcus Mutants

Schwarz¹,

Reinhold²

1995

Plant Physiol.

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The high-C0,-requiring mutant of Synechococcus sp. PCC 7942, EK6, was obtained after extension of the C terminus of the small subunit of ribulose-I ,5-bisphosphate (RuBP) carboxylase/oxygenase (Rubisco). The carboxysomes in EK6 were much larger than in the wild type, but the cellular distribution of the large and small subunits of Rubisco was not affected. The kinetic parameters of in vitro-activated Rubisco were similar in EK6 and in the wild type. On the other hand, Rubisco appeared to be in a low state of activation in situ in EK6 cells pretreated with an air leve1 of CO,. This was deduced from the appearance of a lag phase when carboxylation was followed with time in cells permeabilized by detergent and subsequently supplied with saturating CO, and RuBP. Pretreatment of the cells with high CO, virtually abolished the lag. After low-CO, treatment, the internal RuBP pool was much higher in mutant cells than in the wild-type cells; pretreatment with high CO, reduced the pool in mutant cells. We suggest that the high-C0,-requiring phenotype in mutants that possess aberrant carboxysomes arises from the inactivated state of Rubisco when the cells are exposed to low co,.Cyanobacteria possess polyhedral bodies that contain most of the cellular Rubisco (see Codd, 1988;McKay et al., 1992) and CA activities . Quantitative models (Reinhold et al., 1989) assigned a critica1 role to the structural organization of the carboxysomes in the operation of the CCM. They postulate that CO, is generated within the carboxysomes at CA sites in close proximity to Rubisco. The CCM enable the cells to overcome the 20-fold difference between the concentration of dissolved CO, at equilibrium with air and the K, (CO,) of their Rubisco (see Aizawa and Miyachi, 1986;Badger, 1987;Pierce and Omata, 1988;Kaplan et al., 1990Kaplan et al., , 1991Kaplan et al., , 1994Miller et al., 1990;Coleman, 1991;Badger and Price, 1992, for recent reviews and literature citations).Aberrant carboxysomes were observed in severa1 Syneckococcus sp. PCC 7942 mutants, which demand high CO, for growth. These mutants were isolated after modifications of ORF78, ccmL, ccmM, ccmN, and ccmO, which were located upstream of rbc (Friedberg et al., 1989;

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Section: Resultssupporting

confidence: 87%

Section: Resultssupporting

confidence: 73%

Section: Dlscusslonsupporting

confidence: 73%

Section: Resultsmentioning

confidence: 98%

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Low Activation State of Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase in Carboxysome-Defective Synechococcus Mutants

Schwarz¹,

Reinhold²

1995

Plant Physiol.

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“…The only exception is the complete decarboxylation route, which seems to represent an optional, LC-induced detoxification module in both Synechococcus 7942 and Synechocystis 6803. A shift to LC conditions probably decreases the Calvin-Benson cycle activity in Synechococcus 7942, which is reflected in decreased CO 2 assimilation (Mayo et al, 1989) and coincident accumulation of 3PGA. In addition to limited CO 2 availability for the Calvin-Benson cycle, 3PGA accumulation can also be explained by the observed 2PG accumulation, which is known to directly inhibit Calvin-Benson cycle enzymes, such as phosphofructokinase (Kelly and Latzko, 1977) and triosephosphate isomerase (Husic et al, 1987;Norman and Colman, 1991).…”

Section: Correlation Of Metabolic With Transcriptomic Changes In Wildmentioning

confidence: 99%

Metabolic and Transcriptomic Phenotyping of Inorganic Carbon Acclimation in the Cyanobacterium Synechococcus elongatus PCC 7942

et al. 2011

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The amount of inorganic carbon is one of the main limiting environmental factors for photosynthetic organisms such as cyanobacteria. Using Synechococcus elongatus PCC 7942, we characterized metabolic and transcriptomic changes in cells that had been shifted from high to low CO 2 levels. Metabolic phenotyping indicated an activation of glycolysis, the oxidative pentose phosphate cycle, and glycolate metabolism at lowered CO 2 levels. The metabolic changes coincided with a general reprogramming of gene expression, which included not only increased transcription of inorganic carbon transporter genes but also genes for enzymes involved in glycolytic and photorespiratory metabolism. In contrast, the mRNA content for genes from nitrogen assimilatory pathways decreased. These observations indicated that cyanobacteria control the homeostasis of the carbon-nitrogen ratio. Therefore, results obtained from the wild type were compared with the MP2 mutant of Synechococcus 7942, which is defective for the carbon-nitrogen ratio-regulating PII protein. Metabolites and genes linked to nitrogen assimilation were differentially regulated, whereas the changes in metabolite concentrations and gene expression for processes related to central carbon metabolism were mostly similar in mutant and wild-type cells after shifts to low-CO 2 conditions. The PII signaling appears to down-regulate the nitrogen metabolism at lowered CO 2 , whereas the specific shortage of inorganic carbon is recognized by different mechanisms.

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Molecular Responses to Environmental Stress

Bhaya

Schwarz

Grossman

The Ecology of Cyanobacteria

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The Relationship between Ribulose Bisphosphate Concentration, Dissolved Inorganic Carbon (DIC) Transport and DIC-Limited Photosynthesis in the Cyanobacterium Synechococcus leopoliensis Grown at Different Concentrations of Inorganic Carbon

Abstract: To examine the factors which limit photosynthesis and their role in photosynthetic adaptation to growth at low dissolved inorganic carbon (DIC) ,

Cited by 29 publications

References 27 publications

Low Activation State of Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase in Carboxysome-Defective Synechococcus Mutants

Low Activation State of Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase in Carboxysome-Defective Synechococcus Mutants

Metabolic and Transcriptomic Phenotyping of Inorganic Carbon Acclimation in the Cyanobacterium Synechococcus elongatus PCC 7942

Molecular Responses to Environmental Stress

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