Tissue variation of mitochondrial oxidative phosphorylation efficiency in cold-acclimated ducklings.

2010 ◽  
Vol 57 (4) ◽  
Author(s):  
Karine Salin ◽  
Loïc Teulier ◽  
Benjamin Rey ◽  
Jean-Louis Rouanet ◽  
Yann Voituron ◽  
...  
Keyword(s):  
Oxidative Phosphorylation ◽  
Cold Exposure ◽  
Gastrocnemius Muscle ◽  
Liver Mitochondria ◽  
Proton Leak ◽  
Proton Conductance ◽  
Mitochondrial Oxidative Phosphorylation ◽  
Muscle Mitochondria ◽  
Important Contributor

We investigated the oxidative phosphorylation efficiency of liver and gastrocnemius muscle mitochondria in thermoneutral and cold-acclimated ducklings. The yield of oxidative phosphorylation was lower in muscle than in liver mitochondria, a difference that was associated with a higher proton conductance in muscle mitochondria. Cold exposure did not affect oxidative phosphorylation efficiency or basal proton leak in mitochondria. We conclude that the basal proton conductance of mitochondria may regulate mitochondrial oxidative phosphorylation efficiency, but is not an important contributor to thermogenic processes in cold-acclimated ducklings.

2-Anilino-1.3.4-thiadiazole, Hemmstoffe der oxidativen und photosynthetischen Phosphorylierung

1975 ◽  
Vol 30 (3-4) ◽  
pp. 183-189 ◽  
Author(s):  
G. Schäfer ◽  
A. Trebst ◽  
K. H. Büchel
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Oxidative Phosphorylation ◽  
Benzene Ring ◽  
Inhibitory Action ◽  
Substituent Effects ◽  
Photosynthetic Electron Transport ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Mitochondrial Oxidative Phosphorylation

Abstract 2-anilino-1,3,4-thiadiazoles carrying various substituents in the 5-position as well as in the benzene-ring were synthesized. The compounds were tested with rat-liver-mitochondria and with spinach-chloroplasts and revealed to be potent uncouplers of both, oxidative and photosynthetic phosphorylation, with p I50-values rangeing from 6.79 to 4.05. At higher concentration all compounds are inhibitors of the Hillreaction. In mitochondria a fair correlation exists between pKa of the acidic NH-group and the uncoupling activity; a maximum is obtained around pKa= 6 .8 , whereas in chloroplasts activity is shifted to more acid pKa-values. The compounds meet the requirements for uncouplers according to the chemi-osmotic theory, being lipophilic weak acids. N-methylation causes total loss of activity in mitochondrial oxidative phosphorylation. The inhibitory action on photosynthetic electron transport is located within photosystem II. This latter activity is almost independent of substituent effects in contrast to uncoupling of either respiratory- or photo-phosphorylation

scholarly journals The basal proton conductance of mitochondria depends on adenine nucleotide translocase content

2005 ◽  
Vol 392 (2) ◽  
pp. 353-362 ◽  
Author(s):  
Martin D. Brand ◽  
Julian L. Pakay ◽  
Augustine Ocloo ◽  
Jason Kokoszka ◽  
Douglas C. Wallace ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Metabolic Rate ◽  
Adenine Nucleotide ◽  
Adenine Nucleotide Translocase ◽  
Proton Leak ◽  
Proton Conductance ◽  
Wild Type ◽  
Muscle Mitochondria ◽  
Mild Uncoupling ◽  
Molecular Nature

The basal proton conductance of mitochondria causes mild uncoupling and may be an important contributor to metabolic rate. The molecular nature of the proton-conductance pathway is unknown. We show that the proton conductance of muscle mitochondria from mice in which isoform 1 of the adenine nucleotide translocase has been ablated is half that of wild-type controls. Overexpression of the adenine nucleotide translocase encoded by the stress-sensitive B gene in Drosophila mitochondria increases proton conductance, and underexpression decreases it, even when the carrier is fully inhibited using carboxyatractylate. We conclude that half to two-thirds of the basal proton conductance of mitochondria is catalysed by the adenine nucleotide carrier, independently of its ATP/ADP exchange or fatty-acid-dependent proton-leak functions.

scholarly journals Studies of energy-linked reactions. Inhibition of oxidative phosphorylation by DL-8-methyldihydrolipoate

1977 ◽  
Vol 164 (3) ◽  
pp. 699-704 ◽  
Author(s):  
D E Griffiths ◽  
K Cain ◽  
R L Hyams
Keyword(s):  
Oxidative Phosphorylation ◽  
Lipoic Acid ◽  
Adenosine Triphosphatase ◽  
Potent Inhibitor ◽  
Liver Mitochondria ◽  
Reduced Form ◽  
Rat Liver Mitochondria ◽  
Mitochondrial Oxidative Phosphorylation ◽  
Submitochondrial Particles ◽  
Membrane Bound

1. DL-8-Methyldihydrolipoate was shown to be a potent inhibitor of mitochondrial oxidative phosphorylation and ATP-driven energy-linked reactions. 2. ADP-stimulated respiration utilizing pyruvate + malate and succinate in both ox heart and rat liver mitochondria is inhibited; oxidative phosphorylation using pyruvate + malate, succinate and ascorbate + NNN'N'-tetramethyl-p-phenylenediamine as substrates is also inhibited; uncoupler-stimulated respiration is unaffected regardless of the substrate used. 3. Mitochondrial oligomycin-sensitive adenosine triphosphatase is inhibited in both the membrane-bound form and the purified detergent-dispersed preparation. 4. ATP-driven transhydrogenase and the ATP-driven energy-linked reduction of NAD+ by succinate in ox heart submitochondrial particles are inhibited, whereas the respiratory-chain-driven transhydrogenase is unaffected. 5. DL-8-Methyl-lipoate has no immediate effect on the above reactions, demonstrating the requirement for the reduced form for inhibition. 6. The inhibitory properties of DL-8-methyldihydrolipoate are analogous to those of oligomycin and provide further evidence of a role for lipoic acid in oxidative phosphorylation.

Kinetics and control of oxidative phosphorylation in rat liver mitochondria after chronic ethanol feeding

2000 ◽  
Vol 349 (2) ◽  
pp. 519-526 ◽  
Author(s):  
Ausra MARCINKEVICIUTE ◽  
Vida MILDAZIENE ◽  
Sara CRUMM ◽  
Oleg DEMIN ◽  
Jan B. HOEK ◽  
...  
Keyword(s):  
Oxidative Phosphorylation ◽  
Rat Liver ◽  
Liver Mitochondria ◽  
Proton Leak ◽  
Rat Liver Mitochondria ◽  
Protonmotive Force ◽  
Compensatory Mechanisms ◽  
Mitochondrial Energy Metabolism ◽  
Ethanol Feeding ◽  
And Control

Changes in the kinetics and regulation of oxidative phosphorylation were characterized in isolated rat liver mitochondria after 2 months of ethanol consumption. Mitochondrial energy metabolism was conceptually divided into three groups of reactions, either producing protonmotive force (∆p) (the respiratory subsystem) or consuming it (the phosphorylation subsystem and the proton leak). Manifestation of ethanol-induced mitochondrial malfunctioning of the respiratory subsystem was observed with various substrates; the respiration rate in State 3 was inhibited by 27±4% with succinate plus amytal, by 20±4% with glutamate plus malate, and by 17±2% with N,N,Nʹ,Nʹ-tetramethyl-p-phenylenediamine/ascorbate. The inhibition of the respiratory activity correlated with the lower activities of cytochrome c oxidase, the bc1 complex, and the ATP synthase in mitochondria of ethanol-fed rats. The block of reactions consuming the ∆p to produce ATP (the phosphorylating subsystem) was suppressed after 2 months of ethanol feeding, whereas the mitochondrial proton leak was not affected. The contributions of ∆p supply (the respiratory subsystem) and ∆p demand (the phosphorylation and the proton leak) to the control of the respiratory flux were quantified as the control coefficients of these subsystems. In State 3, the distribution of control exerted by different reaction blocks over respiratory flux was not significantly affected by ethanol diet, despite the marked changes in the kinetics of individual functional units of mitochondrial oxidative phosphorylation. This suggests the operation of compensatory mechanisms, when control redistributes among the different components within the same subsystem.

scholarly journals Influence of ubiquinone on the inhibitory effect of adriamycin on mitochondrial oxidative phosphorylation

1984 ◽  
Vol 217 (2) ◽  
pp. 493-498 ◽  
Author(s):  
H Muhammed ◽  
C K R Kurup
Keyword(s):  
Oxidative Phosphorylation ◽  
Rat Heart ◽  
Liver Mitochondria ◽  
Inhibitory Effect ◽  
Oxidative Activity ◽  
Mitochondrial Oxidative Phosphorylation ◽  
Succinate Oxidation ◽  
Exogenous Addition

The inhibition of succinate oxidation in both heart and liver mitochondria by the cardiotoxic anticancer antibiotic adriamycin in vitro was reversed to a large extent by exogenous ubiquinone-45. Inhibition of the oxidation of NAD+-linked substrates in heart and liver mitochondria responded differently to ubiquinone, the inhibition being reversed only in liver organelles. Administration of adriamycin inhibited oxidative phosphorylation in rat heart, kidney and liver mitochondria, the inhibition being highest in the heart organelles (about 50% for both NAD+-linked substrates and succinate). Exogenous addition of ubiquinone to mitochondria isolated from drug-treated animals did not reverse the inhibition. Administration of ubiquinone along with adriamycin did not change effectively the pattern of drug-mediated decrease in oxidative activity of the organelles, particularly in the heart.

scholarly journals Dietary protein level alters oxidative phosphorylation in heart and liver mitochondria of chicks

1992 ◽  
Vol 68 (1) ◽  
pp. 89-99 ◽  
Author(s):  
Masaaki Toyomizu ◽  
Daisuke Kirihara ◽  
Masahiro Tanaka ◽  
Kunioki Hayashi ◽  
Yuichiro Tomita
Keyword(s):  
Oxidative Phosphorylation ◽  
Body Fat ◽  
Dietary Protein ◽  
Protein Level ◽  
Mitochondrial Protein ◽  
Liver Mitochondria ◽  
Metabolizable Energy ◽  
Mitochondrial Oxidative Phosphorylation ◽  
Dietary Protein Level ◽  
Protein Energy

To determine the effects of dietary protein level on cardiac and hepatic mitochondrial oxidative phosphorylation, chicks were fed on semi-purified diets of different protein levels (7, 25, 43 and 61% of metabolizable energy content) for 7, 14 and 21 d. All diets were formulated to contain equivalent fat, mineral and vitamin contents on a gross energy basis. Cardiac and hepatic mitochondrial oxidative phosphorylation rates were assessed polarographically with pyruvate and malate as substrates. Cardiac mitochondria isolated from chicks fed on a 43 or 61% protein-energy diet for 7 d exhibited significantly reduced ADP:oxygen (ADP:O) ratios when compared with mitochondria isolated from chicks fed on a lower-protein-energy diet. Feeding low- (7%) protein-energy diets for 14 d resulted in a relatively increased ADP:O ratio in the heart. Responses of ADP:O ratios to protein level in hepatic mitochondria showed more dependency on protein level than in heart muscle; at all feeding periods the ADP:O ratio decreased with an increase in protein level. As a result, ATP synthesized in the liver, expressed as nmol/mg mitochondrial protein per min, significantly decreased with increased dietary protein level. A parallel correlation was observed, in chicks fed on diets with different levels of protein, between ADP:O ratio for liver mitochondria and body fat. These results suggest that the reduction in oxidative phosphorylation in the heart and liver of animals fed on a higher protein-energy diet may partly contribute to the depression of body fat.

scholarly journals Differential effects of endurance training and creatine depletion on regional mitochondrial adaptations in rat skeletal muscle

2000 ◽  
Vol 350 (2) ◽  
pp. 547-553 ◽  
Author(s):  
Damien ROUSSEL ◽  
Florence LHENRY ◽  
Laurent ECOCHARD ◽  
Brigitte SEMPORE ◽  
Jean-Louis ROUANET ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Oxidative Phosphorylation ◽  
Endurance Training ◽  
Oxidative Capacity ◽  
Mitochondrial Oxidative Phosphorylation ◽  
Sedentary Control ◽  
Muscle Mitochondria ◽  
F1 Atpase ◽  
Skeletal Muscle Mitochondria ◽  
Subsarcolemmal Mitochondria

To examine the combined effects of 2-week endurance training and 3-week feeding with β-guanidinopropionic acid (GPA) on regional adaptability of skeletal muscle mitochondria, intermyofibrillar mitochondria (IFM) and subsarcolemmal mitochondria (SSM) were isolated from quadriceps muscles of sedentary control, trained control, sedentary GPA-fed and trained GPA-fed rats. Mitochondrial oxidative phosphorylation was assessed polarographically by using pyruvate plus malate, succinate (plus rotenone), and ascorbate plus N,N,N´,N´-tetramethyl-p-phenylenediamine (TMPD) (plus antimycin) as respiratory substrates. Assays of cytochrome c oxidase and F1-ATPase activities were also performed. In sedentary control rats, IFM exhibited a higher oxidative capacity than SSM, whereas F1-ATPase activities were similar. Training increased the oxidative phosphorylation capacity of mitochondria with both pyruvate plus malate and ascorbate plus TMPD as substrates, with no differences between IFM and SSM. In contrast, the GPA diet mainly improved the overall SSM oxidative phosphorylation capacity, irrespective of the substrate used. Finally, the superimposition of training to feeding with GPA strongly increased both oxidase and enzymic activities in SSM, whereas no cumulative effects were found in IFM mitochondria. It therefore seems that endurance training and feeding with GPA, which are both known to alter the energetic status of the muscle cell, might mediate distinct biochemical adaptations in regional skeletal muscle mitochondria.

scholarly journals Kinetics and control of oxidative phosphorylation in rat liver mitochondria after dexamethasone treatment

2004 ◽  
Vol 382 (2) ◽  
pp. 491-499 ◽  
Author(s):  
Damien ROUSSEL ◽  
Jean-François DUMAS ◽  
Gilles SIMARD ◽  
Yves MALTHIÈRY ◽  
Patrick RITZ
Keyword(s):  
Membrane Potential ◽  
Oxidative Phosphorylation ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane ◽  
Liver Mitochondria ◽  
Energetic Cost ◽  
Proton Leak ◽  
Mitochondrial Bioenergetics ◽  
Dexamethasone Treatment ◽  
And Control

The present investigation was undertaken in order to evaluate the contributions of ATP synthesis and proton leak reactions to the rate of active respiration of liver mitochondria, which is altered following dexamethasone treatment (1.5 mg/kg per day for 5 days). We applied top-down metabolic control analysis and its extension, elasticity analysis, to gain insight into the mechanisms of glucocorticoid regulation of mitochondrial bioenergetics. Liver mitochondria were isolated from dexamethasone-treated, pair-fed and control rats when in a fed or overnight fasted state. Injection of dexamethasone for 5 days resulted in an increase in the fraction of the proton cycle of phosphorylating liver mitochondria, which was associated with a decrease in the efficiency of the mitochondrial oxidative phosphorylation process in liver. This increase in proton leak activity occurred with little change in the mitochondrial membrane potential, despite a significant decrease in the rate of oxidative phosphorylation. Regulation analysis indicates that mitochondrial membrane potential homoeostasis is achieved by equal inhibition of the mitochondrial substrate oxidation and phosphorylation reactions in rats given dexamethasone. Our results also suggest that active liver mitochondria from dexamethasone-treated rats are capable of maintaining phosphorylation flux for cellular purposes, despite an increase in the energetic cost of mitochondrial ATP production due to increased basal proton permeability of the inner membrane. They also provide a complete description of the effects of dexamethasone treatment on liver mitochondrial bioenergetics.

scholarly journals Oxygen, pH, and mitochondrial oxidative phosphorylation

2012 ◽  
Vol 113 (12) ◽  
pp. 1838-1845 ◽  
Author(s):  
David F. Wilson ◽  
David K. Harrison ◽  
Sergei A. Vinogradov
Keyword(s):  
Cytochrome C ◽  
Oxidative Phosphorylation ◽  
Respiratory Rate ◽  
Oxygen Sensor ◽  
Mitochondrial Respiratory Chain ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Mitochondrial Oxidative Phosphorylation ◽  
Intact Cells ◽  
Cellular Environment

The oxygen dependence of mitochondrial oxidative phosphorylation was measured in suspensions of isolated rat liver mitochondria using recently developed methods for measuring oxygen and cytochrome c reduction. Cytochrome- c oxidase (energy conservation site 3) activity of the mitochondrial respiratory chain was measured using an artificial electron donor ( N, N, N′, N′-tetramethyl- p-phenylenediamine) and ascorbate to directly reduce the cytochrome c, bypassing sites 1 and 2. For mitochondrial suspensions with added ATP, metabolic conditions approximating those in intact cells and decreasing oxygen pressure both increased reduction of cytochrome c and decreased respiratory rate. The kinetic parameters [ KM and maximal rate ( VM)] for oxygen were determined from the respiratory rates calculated for 100% reduction of cytochrome c. At 22°C, the KM for oxygen is near 3 Torr (5 μM), 12 Torr (22 μM), and 18 Torr (32 μM) at pH 6.9, 7.4, and 7.9, respectively, and VM corresponds to a turnover number for cytochrome c at 100% reduction of near 80/s and is independent of pH. Uncoupling oxidative phosphorylation increased the respiratory rate at saturating oxygen pressures by twofold and decreased the KM for oxygen to <2 Torr at all tested pH values. Mitochondrial oxidative phosphorylation is an important oxygen sensor for regulation of metabolism, nutrient delivery to tissues, and cardiopulmonary function. The decrease in KM for oxygen with acidification of the cellular environment impacts many tissue functions and may give transformed cells a significant survival advantage over normal cells at low-pH, oxygen-limited environment in growing tumors.

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