Characterization of an Electron Transport Pathway Associated with Glucose and Fructose Respiration in the Intact Chloroplasts of <i>Chlamydomonas reinhardtii</i> and Spinach

Singh, Kausal K.; Chen, Changguo; Gibbs, Martin

doi:10.1104/pp.100.1.327

Cited by 17 publications

(7 citation statements)

References 33 publications

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“…The usage of these metabolic inhibitors in showing the interactions between chloroplasts and mitochondria is well proven (Padmasree and Raghavendra 1999a, 1999b, 1999c, 2001a, 2001b, Strodtkötter et al 2009, Yoshida et al 2006). At the low concentrations of SHAM (0.5 m M ) used to monitor (1) ‐ and p ‐benzoquinone (BQ)‐dependent O 2 evolution, (2) intracellular malate and pyruvate levels in the present study, it neither stimulates peroxidases (Lambers 1985, Møller et al 1988) nor affects chlororespiration (Singh et al 1992) or chloroplastic glycolate‐quinone oxidoreductase (Goyal and Tolbert 1996).…”

Section: Introductionmentioning

confidence: 68%

Importance of AOX pathway in optimizing photosynthesis under high light stress: role of pyruvate and malate in activating AOX

Challabathula

Raghavendra

Padmasree

2010

Physiologia Plantarum

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The present study shows the importance of alternative oxidase (AOX) pathway in optimizing photosynthesis under high light (HL). The responses of photosynthesis and respiration were monitored as O(2) evolution and O(2) uptake in mesophyll protoplasts of pea pre-incubated under different light intensities. Under HL (3000 micromol m(-2) s(-1)), mesophyll protoplasts showed remarkable decrease in the rates of NaHCO(3)-dependent O(2) evolution (indicator of photosynthetic carbon assimilation), while decrease in the rates of respiratory O(2) uptake were marginal. While the capacity of AOX pathway increased significantly by two fold under HL, the capacity of cytochrome oxidase (COX) pathway decreased by >50% compared with capacities under darkness and normal light (NL). Further, the total cellular levels of pyruvate and malate, which are assimilatory products of active photosynthesis and stimulators of AOX activity, were increased remarkably parallel to the increase in AOX protein under HL. Upon restriction of AOX pathway using salicylhydroxamic acid (SHAM), the observed decrease in NaHCO(3)-dependent O(2) evolution or p-benzoquinone (BQ)-dependent O(2) evolution [indicator of photosystem II (PSII) activity] and the increase in total cellular levels of pyruvate and malate were further aggravated/promoted under HL. The significance of raised malate and pyruvate levels in activation of AOX protein/AOX pathway, which in turn play an important role in dissipating excess chloroplastic reducing equivalents and sustenance of photosynthetic carbon assimilation to balance the effects of HL stress on photosynthesis, was depicted as a model.

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Section: Introductionmentioning

confidence: 68%

Importance of AOX pathway in optimizing photosynthesis under high light stress: role of pyruvate and malate in activating AOX

Challabathula

Raghavendra

Padmasree

2010

Physiologia Plantarum

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“…These results were not affected by externally supplied ATP. Release of CO2 from Glc-6-P was unaffected by trypsin, indicating that the multistep pathway including Glc-6-P dehydrogenase, gluconate-6-P, and the electron transport chain (Singh et al, 1992) remained. With respect to our assay, trypsin eliminated selectively the kinase reactions.…”

Section: Effed Of Proteases On Coz Evolutionmentioning

confidence: 99%

Respiration of Sugars in Spinach (Spinacia oleracea), Maize (Zea mays), and Chlamydomonas reinhardtii F-60 Chloroplasts with Emphasis on the Hexose Kinases

et al. 1993

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The role of hexokinase in carbohydrate degradation in isolated, intact chloroplasts was evaluated. This was accomplished by monitoring the evolution of l4COZ from darkened spinach (Spinacia oleracea), maize (Zea mays) mesophyll, and Chlamydomonas reinhardtii chloroplasts externally supplied with "C-labeled frudose, glucose, mannose, galadose, maltose, and ribose. Clucose and ribose were the preferred substrates with the Chlamydomonas and maize chloroplasts, respectively. The rate of COz release from fructose was about twice that from glucose in the spinach chloroplast. Externally supplied ATP stimulated the rate of COz release.The pH optimum for COz release was 7.5 with ribose and fructose and 8.5 with glucose as substrates. Probing the outer membrane polypeptides of the intact spinach chloroplast with two proteases, trypsin and thermolysin, decreased ' T O p release from glucose about 50% but had little effect when fructose was the substrate.Tryptic digestion decreased COz release from glucose in the Cblamydomonas chloroplast about 70%. "COZ evolution from [1-14C]-glucose-6-phosphate in both chloroplasts was unaffeded by treatment with trypsin. Enzymic analysis of the supernatant (stroma) of the lysed spinach chloroplast indicated a hexokinase adive primarily with fructose but with some affinity for glucose. The pellet (membrana1 fradion) contained a hexokinase utilizing both glucose and fructose but with considerably less total activity than the stromal enzyme. Treatment with trypsin and thermolysin eliminated more than 50% of the glucokinase activity but had little effect on frudokinase activity in the spinach chloroplast. Tryptic digestion of the Chlamydomonas chloroplast resulted in a loss of about 90% of glucokinase activity. Saltman (1953), the first to investigate hexokinase in higher plants, observed that at least 20% of the total hexokinase activity in leaves was in the particulate cell fraction, the rest being in the cytosol. Resolution of the total hexokinase activity revealed four kinases in spinach leaves: two hexokinases active with Glc, Fru, and Man and two fructokinases functioning primarily with Fru but to a far lesser extent with Glc and Man (Baldus et al., 1981;Schnarrenberger, 1990). Essentially similar results have been described for pea seed (Copeland et al., 1978; Tumer and Copeland,

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“…Evidence of the existence of chlororespiratory activity in higher plants has also been presented (Garab et al, 1989;Singh et al, 1992;Gruszecki et al, 1994). Such a process might be important during leaf senescence (Cuello et al, 1995b).…”

mentioning

confidence: 95%

Association of Ferredoxin-NADP Oxidoreductase with the Chloroplastic Pyridine Nucleotide Dehydrogenase Complex in Barley Leaves1

Quiles

Cuello

1998

Plant Physiology

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Barley (Hordeum vulgare L.) leaves were used to isolate and characterize the chloroplast NAD(P)H dehydrogenase complex. The stroma fraction and the thylakoid fraction solubilized with sodium deoxycholate were analyzed by native polyacrylamide gel electrophoresis, and the enzymes detected with NADH and nitroblue tetrazolium were electroeluted. The enzymes electroeluted from band S from the stroma fraction and from bands T1 (ET1) and T2 from the thylakoid fraction solubilized with sodium deoxycholate had ferredoxin-NADP oxidoreductase (FNR; EC 1.18. 1.2) and NAD(P)H-FeCN oxidoreductase (NAD[P]H-FeCNR) activities.Their NADPH-FeCNR activities were inhibited by 2-monophosphoadenosine-5-diphosphoribose and by enzyme incubation with p-chloromercuriphenylsulfonic acid (p-CMPS), NADPH, and p-CMPS plus NADPH. They presented Michaelis constant NADPH values that were similar to those of FNRs from several sources. Their NADH-FeCNR activities, however, were not inhibited by 2-monophosphoadenosine-5-diphosphoribose but were weakly inhibited by enzyme incubation with NADH, p-CMPS, and p-CMPS plus NADH. We found that only ET1 contained two polypeptides of 29 and 35 kD, which reacted with the antibodies raised against the mitochondrial complex I TYKY subunit and the chloroplast ndhA gene product, respectively. However, all three enzymes contained two polypeptides of 35 and 53 kD, which reacted with the antibodies raised against barley FNR and the NADHbinding 51-kD polypeptide of the mitochondrial complex I, respectively. The results suggest that ET1 is the FNR-containing thylakoidal NAD(P)H dehydrogenase complex.

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Characterization of an Electron Transport Pathway Associated with Glucose and Fructose Respiration in the Intact Chloroplasts of Chlamydomonas reinhardtii and Spinach

Cited by 17 publications

References 33 publications

Importance of AOX pathway in optimizing photosynthesis under high light stress: role of pyruvate and malate in activating AOX

Importance of AOX pathway in optimizing photosynthesis under high light stress: role of pyruvate and malate in activating AOX

Respiration of Sugars in Spinach (Spinacia oleracea), Maize (Zea mays), and Chlamydomonas reinhardtii F-60 Chloroplasts with Emphasis on the Hexose Kinases

Association of Ferredoxin-NADP Oxidoreductase with the Chloroplastic Pyridine Nucleotide Dehydrogenase Complex in Barley Leaves1

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