Compartmentation of Organic Acids in Corn Roots. III. Utilization of Exogenously Supplied Acids

Steer, B. T.; Beevers, Harry

doi:10.1104/pp.42.9.1197

Cited by 17 publications

(8 citation statements)

References 6 publications

(6 reference statements)

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“…More generally, the slow labeling of organic acids and amino acids derived from them is consistent with the idea that glycolysis and the TCAC are inhibited in the light, when the TCAC operates in a noncyclic manner (Tcherkez et al, 2009(Tcherkez et al, , 2012aSweetlove et al, 2010). The very low enrichment in organic acids like isocitrate, fumarate, and malate can also be explained because the vast majority of these metabolites are located in the vacuole (Table 1; Beevers, 1966a, 1966b;Steer and Beevers, 1967).…”

Section: Discussionsupporting

confidence: 58%

Metabolic Fluxes in an Illuminated Arabidopsis Rosette

et al. 2013

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Photosynthesis is the basis for life, and its optimization is a key biotechnological aim given the problems of population explosion and environmental deterioration. We describe a method to resolve intracellular fluxes in intact Arabidopsis thaliana rosettes based on time-dependent labeling patterns in the metabolome. Plants photosynthesizing under limiting irradiance and ambient CO 2 in a custom-built chamber were transferred into a 13 CO 2 -enriched environment. The isotope labeling patterns of 40 metabolites were obtained using liquid or gas chromatography coupled to mass spectrometry. Labeling kinetics revealed striking differences between metabolites. At a qualitative level, they matched expectations in terms of pathway topology and stoichiometry, but some unexpected features point to the complexity of subcellular and cellular compartmentation. To achieve quantitative insights, the data set was used for estimating fluxes in the framework of kinetic flux profiling. We benchmarked flux estimates to four classically determined flux signatures of photosynthesis and assessed the robustness of the estimates with respect to different features of the underlying metabolic model and the time-resolved data set.

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Section: Discussionsupporting

confidence: 58%

Metabolic Fluxes in an Illuminated Arabidopsis Rosette

et al. 2013

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“…The problem of intracellular compartmentation has been extensively studied in corn roots (15,23,24,26,38), in the green alga Scenedesmus (27), and in beet discs (31). It has been established that plant cells contain at least two pools of each organic acid.…”

Section: Discussionmentioning

confidence: 99%

The Effect of Light on the Tricarboxylic Acid Cycle in Green Leaves

Chapman

Graham²

1974

Plant Physiol.

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Long term feeding of acetate-2-"C, "'CO2, citrate-i , fumarate-2,3-"C, and succinate-2,3-"C to mung bean (Phaseolus aureus L. var. Mungo) leaves in the dark gave labeling predominantly [33] of the results of Barker [1]) and in the tricarboxylic acid cycle in bananas (28).The crossover theorem has been applied in the present study to the tricarboxylic acid cycle intermediates during dark/light/ dark transitions which are likely to result in changes in carbon flux. The main conclusions drawn from the analysis are that the tricarboxylic acid cycle in mung bean leaves undergoes a series of changes in control points at citrate synthase, fumarase, isocitrate and malate dehydrogenases during the transition from dark to light. The changes can be correlated with known lightinduced changes of the adenine nucleotides (34) and of the nicotinamide adenine dinucleotides (13,16,19,29,30). After the major initial changes in the light, the "C-labeled intermediates of the tricarboxylic acid cycle approximate to a new steady state in which it appears probable that the ratio of oxidizedreduced NAD continues to play an important role in the regulation of the cycle. On transition from light to dark the major apparent control point is at isocitrate dehydrogenase. MATERIALS AND METHODSThe growth of mung bean seedlings (Phaseolus aureuis L.var. Mungo) and the experimental and analytical procedures have been described in the previous paper (9). RESULTS

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“…Lack of a permeability increase with succinate, which has lower distribution coefficients to lipid solvents than do the aliphatic acids, can be explained by failure of sufficient amounts of the hydrophilic succinic acid molecules to penetrate the membranes involved. These experiments suggest that undissociated acid in root membranes can increase permeability of the roots.Entry of weak organic acids into plants has been known for many years (1,4,18). They are generally thought to enter by distribution to the lipid-protein of the cellular membranes (see Ref.…”

mentioning

confidence: 99%

“…Entry of weak organic acids into plants has been known for many years (1,4,18). They are generally thought to enter by distribution to the lipid-protein of the cellular membranes (see Ref.…”

mentioning

confidence: 99%

Effects of Organic Acids on Ion Uptake and Retention in Barley Roots

Jackson

Taylor

1970

Plant Physiol.

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Effects of several organic acids on ion uptake and retention and on respiration in barley roots having low and high KCI contents were assayed by measurements of K+, Na+, Ca2+, Cl-, and oxygen uptake. Organic acids with high pKa values increase the permeability of roots to ions and decrease respiration when present in sufficient concentrations at pH 5 but have no inhibitory effects at pH 7. Absence of respiratory inhibition in short times and at lower organic acid concentrations, under conditions that immediately produce a permeability increase, indicate that the permeability change is not a result of respiratory inhibition. Effects of formate, acetate, propionate, and glutarate are attributed to entry of undissociated acid molecules into the effective membranes. Lack of a permeability increase with succinate, which has lower distribution coefficients to lipid solvents than do the aliphatic acids, can be explained by failure of sufficient amounts of the hydrophilic succinic acid molecules to penetrate the membranes involved. These experiments suggest that undissociated acid in root membranes can increase permeability of the roots.Entry of weak organic acids into plants has been known for many years (1,4,18). They are generally thought to enter by distribution to the lipid-protein of the cellular membranes (see Ref. 1, for review), in part because of enhanced effects with decrease in pH. Most of these acids, however, are toxic at moderate concentrations and low pH at which inorganic salts are tolerated (7,16). Evidence that organic acids are taken up as anions by plant roots has only recently been advanced (9). Considerations of the entry of organic anions require some clarification of the nature of the interaction of the undissociated acid with roots.Measurements of salt loss from roots in the presence of several weak organic acids as shown here indicate that the limiting membranes are modified under usual experimental conditions. Changes in metabolic rates are shown to be secondary to these modifications. The conclusion is that the acid anion can enter the root without evident modification of the root membranes. The undissociated acid in sufficient concentration, however, modifies the membrane so as to alter the response toward inorganic salts and possibly toward the acid itself. MATERIALS AND METHODSThe roots were from 6-day-old seedlings of barley (Hordewn vulgare, var. Compana and var. Trebi) which had been dark grown in aerated 2 X 10-4 M CaSO4, pH 5.6 at 25 C. High KCl roots were from seedlings grown in 10-3 M KCI + 2 X 10-4 M CaSO4 at pH 5.6 for 8 hr on the 5th day. Roots were excised and rinsed several times just before use.Details of procedure and conditions for the experiments were the same as those used previously (8). Briefly, the roots were maintained in aerated organic acid salt solutions at 23 to 25 C, from which successive root samples were withdrawn periodically, rinsed with water four times, and weighed. Sampling times varied from 5 min to 24 hr. Half-gram root samples were dried in the ...

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Compartmentation of Organic Acids in Corn Roots. III. Utilization of Exogenously Supplied Acids

Cited by 17 publications

References 6 publications

Metabolic Fluxes in an Illuminated Arabidopsis Rosette

Metabolic Fluxes in an Illuminated Arabidopsis Rosette

The Effect of Light on the Tricarboxylic Acid Cycle in Green Leaves

Effects of Organic Acids on Ion Uptake and Retention in Barley Roots

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