Separation of mitochondria from microbodies of Pisum sativum (L. cv. Alaska) cotyledons

Burgess, N.; Beakes, Gordon W.; Thomas, David

doi:10.1007/bf00397341

Cited by 30 publications

(14 citation statements)

References 13 publications

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“…Mitochondrial integrity was assessed as described by Schwitzguebel and Siegenthaler (1984). The proportion (percentage) of intact mitochondria was calculated according to the following formula (Burgess et al, 1985): 100 ÿ 100 3 ðactivity detected with intact organellesÞ ðactivity detected with permealizedÞ…”

Section: Isolation Of Mitochondria and Oxygen Uptakementioning

confidence: 99%

Involvement of a Glycerol-3-Phosphate Dehydrogenase in Modulating the NADH/NAD+ Ratio Provides Evidence of a Mitochondrial Glycerol-3-Phosphate Shuttle in Arabidopsis

et al. 2006

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A mitochondrial glycerol-3-phosphate (G-3-P) shuttle that channels cytosolic reducing equivalent to mitochondria for respiration through oxidoreduction of G-3-P has been extensively studied in yeast and animal systems. Here, we report evidence for the operation of such a shuttle in Arabidopsis thaliana. We studied Arabidopsis mutants defective in a cytosolic G-3-P dehydrogenase, GPDHc1, which, based on models described for other systems, functions as the cytosolic component of a G-3-P shuttle. We found that the gpdhc1 T-DNA insertional mutants exhibited increased NADH/NAD þ ratios compared with wild-type plants under standard growth conditions, as well as impaired adjustment of NADH/NAD þ ratios under stress simulated by abscisic acid treatment. The altered redox state of the NAD(H) pool was correlated with shifts in the profiles of metabolites concerning intracellular redox exchange. The impairment in maintaining cellular redox homeostasis was manifest by a higher steady state level of reactive oxygen species under standard growth conditions and by a significantly augmented hydrogen peroxide production under stress. Loss of GPDHc1 affected mitochondrial respiration, particularly through a diminished capacity of the alternative oxidase respiration pathway. We propose a model that outlines potential involvements of a mitochondrial G-3-P shuttle in plant cells for redox homeostasis.

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Section: Isolation Of Mitochondria and Oxygen Uptakementioning

confidence: 99%

Involvement of a Glycerol-3-Phosphate Dehydrogenase in Modulating the NADH/NAD+ Ratio Provides Evidence of a Mitochondrial Glycerol-3-Phosphate Shuttle in Arabidopsis

et al. 2006

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“…Total organelle activity was measured after lysis of the organelle by the addition of 0.01% (v/v) Triton X-100 (final concentration). The percentage of latency of activity was calculated using the formula of Burgess et al (1985).…”

Section: Determinations Of Enzyme Latencymentioning

confidence: 99%

Evidence for the Presence of the Ascorbate-Glutathione Cycle in Mitochondria and Peroxisomes of Pea Leaves

et al. 1997

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l h e presence of the enzymes of the ascorbate-glutathione cycle was investigated in mitochondria and peroxisomes purified from pea (Pisum sativum L.) leaves. AI1 four enzymes, ascorbate peroxidase (APX; EC 1.1 1.1.1 l ) , monodehydroascorbate reductase (EC 1.6.5.4), dehydroascorbate reductase (EC 1.8.5.1), and glutathione reductase (EC 1.6.4.2), were present in mitochondria and peroxisomes, as well as i n the antioxidants ascorbate and glutathione. l h e activity of the ascorbate-glutathione cycle enzymes was higher in mitochondria than in peroxisomes, except for APX, which was more active in peroxisomes than in mitochondria. lntact mitochondria and peroxisomes had no latent APX activity, and this remained i n the membrane fraction after solubilization assays with 0.2 M KCI.Monodehydroascorbate reductase was highly latent in intact mitochondria and peroxisomes and was membrane-bound, suggesting that the electron acceptor and donor sites of this redox protein are not on the externa1 side of the mitochondrial and peroxisomal membranes. Dehydroascorbate reductase was found mainly in the soluble peroxisomal and mitochondrial fractions. Clutathione reductase had a high latency in mitochondria and peroxisomes and was present i n the soluble fractions of both organelles. I n intact peroxisomes and mitochondria, the presence of reduced ascorbate and glutathione and the oxidized forms of ascorbate and glutathione were demonstrated by high-performance liquid chromatography analysis. l h e ascorbate-glutathione cycle of mitochondria and peroxisomes could represent an important antioxidant protection system against H,O, generated in both plant organelles.

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“…Latency of enzymes was determined in hyposmotic medium (broken organelles) and isosmotic medium (intact organelles) with or without 0.02% Triton X-100, respectively, except in the case of cytochrome c oxidase, in which a non-inhibitory 0.01% Triton concentration was used. The latency, expressed in percent, was calculated by the formula of Burgess et al (1985):…”

Section: Organelle Integrity and Intramitochondrial Localization Of Ementioning

confidence: 99%

The Antioxidants of Legume Nodule Mitochondria

Iturbe‐Ormaetxe¹,

Matamoros²,

Rubio³

et al. 2001

MPMI

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The mitochondria of legume root nodules are critical to sustain the energy-intensive process of nitrogen fixation. They also generate reactive oxygen species at high rates and thus require the protection of antioxidant enzymes and metabolites. We show here that highly purified mitochondria from bean nodules (Phaseolus vulgaris L. cv. Contender × Rhizobium leguminosarum bv. phaseoli strain 3622) contain ascorbate peroxidase primarily in the inner membrane (with lesser amounts detected occasionally in the matrix), guaiacol peroxidases in the outer membrane and matrix, and manganese superoxide dismutase (MnSOD) and an ascorbate-regenerating system in the matrix. This regenerating system relies on homoglutathione (instead of glutathione) and pyridine nucleotides as electron donors and involves the enzymes monodehy-droascorbate reductase, dehydroascorbate reductase, and homoglutathione reductase. Homoglutathione is synthesized in the cytosol and taken up by the mitochondria and bacteroids. Although bacteroids synthesize glutathione, it is not exported to the plant in significant amounts. We propose a model for the detoxification of peroxides in nodule mitochondria in which membrane-bound ascorbate peroxidase scavenges the peroxide formed by the electron transport chain using ascorbate provided by L-galactono-1,4-lactone dehydrogenase in the inner membrane. The resulting monodehydroascorbate and dehydroascorbate can be recycled in the matrix or cytosol. In the matrix, the peroxides formed by oxidative reactions and by MnSOD may be scavenged by specific isozymes of guaiacol peroxidase, ascorbate peroxidase, and catalase.

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Separation of mitochondria from microbodies of Pisum sativum (L. cv. Alaska) cotyledons

Cited by 30 publications

References 13 publications

Involvement of a Glycerol-3-Phosphate Dehydrogenase in Modulating the NADH/NAD+ Ratio Provides Evidence of a Mitochondrial Glycerol-3-Phosphate Shuttle in Arabidopsis

Involvement of a Glycerol-3-Phosphate Dehydrogenase in Modulating the NADH/NAD+ Ratio Provides Evidence of a Mitochondrial Glycerol-3-Phosphate Shuttle in Arabidopsis

Evidence for the Presence of the Ascorbate-Glutathione Cycle in Mitochondria and Peroxisomes of Pea Leaves

The Antioxidants of Legume Nodule Mitochondria

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