References of "Sluse, Francis"
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See detailThe energy-conserving and energy-dissipating processes in mitochondria isolated from wild type and nonripening tomato fruits during development on the plant.
Almeida, A.; Navet, R.; Jarmuszkiewicz, W. et al

in Journal of Bioenergetics & Biomembranes (2002), 34(6), 487-498

Bioenergetics of tomato (Lycopersicon esculentum) development on the plant was followed from the early growing stage to senescence in wild type (climacteric) and nonripening mutant (nor, non-climacteric ... [more ▼]

Bioenergetics of tomato (Lycopersicon esculentum) development on the plant was followed from the early growing stage to senescence in wild type (climacteric) and nonripening mutant (nor, non-climacteric) fruits. Fruit development was expressed in terms of evolution of chlorophyll a content allowing the assessment of a continuous time-course in both cultivars. Measured parameters: the cytochrome pathway-dependent respiration, i.e., the ATP synthesis-sustained respiration (energy-conserving), the uncoupling protein (UCP) activity-sustained respiration (energy-dissipating), the alternative oxidase(AOX)-mediated respiration (energy-dissipating), as well as the protein expression of UCP and AOX, and free fatty acid content exhibited different evolution patterns in the wild type and nor mutant that can be attributed to their climacteric/nonclimacteric properties, respectively. In the wild type, the climacteric respiratory burst observed in vitro depended totally on an increse in the cytochrome pathway activity sustained by ATP synthesis, while the second respiratory rise during the ripening stage was linked to a strong increase in AOX activity accompanied by an overexpression of AOX protein. In wild type mitochondria, the 10-microM linoleic acid-stimulated UCP-activity-dependent respiration remained constant during the whole fruit development except in senescence where general respiratory decay was observed. [less ▲]

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See detailThe effect of pH on the alternative oxidase activity in isolated Acanthamoeba castellanii mitochondria.
Jarmuszkiewicz, W.; Hryniewiecka, L.; Sluse, Francis ULg

in Journal of Bioenergetics & Biomembranes (2002), 34(3), 221-226

Mitochondria of Acanthamoeba castellanii possess a cyanide-resistant GMP-stimulated ubiquinol alternative oxidase in addition to the cytochrome pathway. In a previous work it has been observed that an ... [more ▼]

Mitochondria of Acanthamoeba castellanii possess a cyanide-resistant GMP-stimulated ubiquinol alternative oxidase in addition to the cytochrome pathway. In a previous work it has been observed that an interaction between the two ubiquinol-oxidizing pathways exists in intact A. castellanii mitochondria and that this interaction may be due to a high sensitivity of the alternative oxidase to matrix pH. In this study we have shown that the alternative oxidase activity reveals a pH-dependence with a pH optimum at 6.8 whatever the reducing substrate may be. The GMP stimulation of alternative oxidase is also strongly dependent on pH implicating probably protonation/deprotonation processes at the level of ligand and protein with an optimum pH at 6.8. The ubiquinone redox state-dependence of alternative oxidase activity is modified by pH in such a way that the highest activity for a given ubiquinone redox state is observed at pH 6.8. Thus pH, binding of GMP, and redox state of ubiquinone collaborate to set the activity of the GMP-stimulated alternative oxidase in isolated A. castellanii mitochondria. The high pH sensitivity of the alternative oxidase could link inactivation of the cytochrome pathway proton pumps to activation of the alternative oxidase with acceleration of redox free energy dissipation as a consequence. [less ▲]

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See detailInteractions between the cytochrome pathway and the alternative oxidase in isolated Acanthamoeba castellanii mitochondria.
Jarmuszkiewicz, W.; Sluse, Francis ULg; Hryniewiecka, L. et al

in Journal of Bioenergetics & Biomembranes (2002), 34(1), 31-40

The steady-state activity of the two quinol-oxidizing pathways of Acanthamoeba castellanii mitochondria, the phosphorylating cytochrome pathway (i.e. the benzohydroxamate(BHAM)-resistant respiration in ... [more ▼]

The steady-state activity of the two quinol-oxidizing pathways of Acanthamoeba castellanii mitochondria, the phosphorylating cytochrome pathway (i.e. the benzohydroxamate(BHAM)-resistant respiration in state 3) and the alternative oxidase (i.e. the KCN-resistant respiration), is shown to be fixed by ubiquinone (Q) pool redox state independently of the reducing substrate (succinate or exogenous reduced nicotinamide adenine dinucleotide (NADH)), indicating that the active Q pool is homogenous. For both pathways, activity increases with the Q reduction level (up to 80%). However, the cytochrome pathway respiration partially inhibited (about 50%) by myxothiazol decreases when the Q reduction level increases above 80%. The decrease can be explained by the Q cycle mechanism of complex III. It is also shown that BHAM has an influence on the relationship between the rate of ADP phosphorylation and the Q reduction level when alternative oxidase is active, and that KCN has an influence on the relationship between the alternative oxidase activity and the Q reduction level. These unexpected effects of BHAM and KCN observed at a given Q reduction level are likely due to functional connections between the two pathways activities or to protein-protein interaction. [less ▲]

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See detailUncoupling proteins outside the animal and plant kingdoms: functional and evolutionary aspects.
Sluse, Francis ULg; Jarmuszkiewicz, W.

in FEBS Letters (2002), 510

The appearance of intracellular oxidative phosphorylation at the time of acquisition of mitochondria in Eukarya was very soon accompanied by the emergence of uncoupling protein, a carrier specialized in ... [more ▼]

The appearance of intracellular oxidative phosphorylation at the time of acquisition of mitochondria in Eukarya was very soon accompanied by the emergence of uncoupling protein, a carrier specialized in free fatty acid-mediated H(+) recycling that can modulate the tightness of coupling between mitochondrial respiration and ATP synthesis, thereby maintaining a balance between energy supply and demand in the cell and defending cells against damaging reactive oxygen species production when electron carriers of the respiratory chain become over-reduced. The simultaneous occurrence of redox free energy-dissipating oxidase, which has the same final effect, could be related to the functional interactions between both dissipative systems [less ▲]

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See detailDynamics of H+ fluxes in mitochondrial membrane.
Sluse, Francis ULg; Jarmuszkiewicz, W.

in Rengel, Z. (Ed.) Handbook of plan growth : pH as the master variable (2001)

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See detailAlternative oxidase and uncoupling protein: thermogenesis versus cell energy balance.
Jarmuszkiewicz, W.; Sluse-Goffart, C.; Vercesi, A. et al

in Bioscience Reports (2001), 21(2), 213-222

The physiological role of an alternative oxidase and an uncoupling protein in plant and protists is discussed in terms of thermogenesis and energy metabolism balance in the cell. It is concluded that ... [more ▼]

The physiological role of an alternative oxidase and an uncoupling protein in plant and protists is discussed in terms of thermogenesis and energy metabolism balance in the cell. It is concluded that thermogenesis is restricted not only by a lower-limit size but also by a kinetically-limited stimulation of the mitochondrial respiratory chain. [less ▲]

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See detailKinetics of light emission and oxygen consumption by bioluminescent bacteria.
Bourgeois, J. J.; Sluse, Francis ULg; Baguet, F. et al

in Journal of Bioenergetics & Biomembranes (2001), 33

Oxygen plays a key role in bacterial bioluminescence. The simultaneous and continuous kinetics of oxygen consumption and light emission during a complete exhaustion of the exogenous oxygen present in a ... [more ▼]

Oxygen plays a key role in bacterial bioluminescence. The simultaneous and continuous kinetics of oxygen consumption and light emission during a complete exhaustion of the exogenous oxygen present in a closed system has been investigated. The kinetics are performed with Vibrio fischeri, V. harveyi, and Photobacterium phosphoreum incubated on respiratory substrates chosen for their different reducing power. The general patterns of the luminescence time courses are different among species but not among substrates. During steady-state conditions, substrates, which are less reduced than glycerol, have, paradoxally, a better luminescence efficiency. Oxygen consumption by luciferase has been evaluated to be approximately 17% of the total respiration. Luciferase is a regulatory enzyme presenting a positive cooperative effect with oxygen and its affinity for this final electron acceptor is about 4-5 times higher than the one of cytochrome oxidase. The apparent Michaelis constant for luciferase has been evaluated to be in the range of 20 to 65 nM O2. When O2 concentrations are as low as 10 nM, luminescence can still be detected; this means that above this concentration, strict anaerobiosis does not exist. By n-butyl malonate titration, it was clearly shown that electrons enter the luciferase pathway only when the cytochrome pathway is saturated. It is suggested that, in bioluminescent bacteria, luciferase acts as a free-energy dissipating valve when anabolic processes (biomass production) are impaired. [less ▲]

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See detailRespiratory chain network in mitochondria of Candida parapsilosis: ADP/O appraisal of the multiple electron pathways.
Milani, G.; Jarmuszkiewicz, W.; Sluse-Goffart, C. et al

in FEBS Letters (2001), 508

In this study we demonstrated that mitochondria of Candida parapsilosis contain a constitutive ubiquinol alternative oxidase (AOX) in addition to a classical respiratory chain (CRC) and a parallel ... [more ▼]

In this study we demonstrated that mitochondria of Candida parapsilosis contain a constitutive ubiquinol alternative oxidase (AOX) in addition to a classical respiratory chain (CRC) and a parallel respiratory chain (PAR) both terminating by two different cytochrome c oxidases. The C. parapsilosis AOX is characterized by a fungi-type regulation by GMP (as a stimulator) and linoleic acid (as an inhibitor). Inhibitor screening of the respiratory network by the ADP/O ratio and state 3 respiration determinations showed that (i) oxygen can be reduced by the three terminal oxidases through four paths implying one bypass between CRC and PAR and (ii) the sum of CRC, AOX and PAR capacities is higher than the overall respiration (no additivity) and that their engagement could be progressive according to the redox state of ubiquinone, i.e. first cytochrome pathway, then AOX and finally PAR. [less ▲]

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See detailTransplantation pulmonaire et fonction mitochondriale
Detry, Olivier ULg; Willet, K.; Meurisse, Michel ULg et al

in Bulletin et Mémoires de l'Académie Royale de Médecine de Belgique (2001), 156(6, Pt 2), 355-9

The mechanisms of cellular lesions induced by lung ischemia and reperfusion are not fully understood and, in particular, the consequences of pulmonary ischemia and reperfusion injury on mitochondrial ... [more ▼]

The mechanisms of cellular lesions induced by lung ischemia and reperfusion are not fully understood and, in particular, the consequences of pulmonary ischemia and reperfusion injury on mitochondrial function have not been previously investigated. Therefore, we studied the respiratory function of isolated pulmonary mitochondria in a swine model of lung ischemia and reperfusion. We demonstrated that prolonged hypothermic (4 degrees C) ischemia induces significant lesions of the mitochondrial respiratory chain, particularly if ischemia is followed by normothermic reperfusion. These results should be integrated in the cellular alterations induced by the ischemia-reperfusion injury. In another swine model mimicking controlled non-heart beating donors, we demonstrated that thirty minutes of cardiac arrest do not promote significant alteration of the mitochondrial respiratory function. In contrast, forty-five minutes of cardiac arrest, induced significant mitochondrial lesions. This pulmonary tolerance to normothermic cardiac arrest might be explained by the presence of air in the lung airways, allowing some aerobic metabolism after circulatory arrest. These results suggested that lung grafts might be harvested from non-heart beating donors after thirty minutes of cardiac arrest, significantly increasing the pulmonary graft pool. [less ▲]

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See detailResistance of Isolated Pulmonary Mitochondria During in Vitro Anoxia/Reoxygenation
Willet, K.; Detry, Olivier ULg; Sluse, Francis ULg

in Biochimica et Biophysica Acta (2000), 1460(2-3), 346-52

The aim of the study was to investigate the effect of in vitro anoxia/reoxygenation on the oxidative phosphorylation of isolated lung mitochondria. Mitochondria were isolated after harvesting from fresh ... [more ▼]

The aim of the study was to investigate the effect of in vitro anoxia/reoxygenation on the oxidative phosphorylation of isolated lung mitochondria. Mitochondria were isolated after harvesting from fresh pig lungs flushed with Euro-Collins solution. Mitochondrial respiratory parameters were determined in isolated mitochondria before anoxia (control), after 5-45 min anoxia followed by 5 min reoxygenation, and after 25 or 40 min of in vitro incubation in order to follow the in vitro aging of mitochondria during respiratory assays. Respiratory parameters measured after anoxia/reoxygenation did not show any oxidative phosphorylation dysfunction, indicating a high resistance of pulmonary mitochondria to in vitro anoxia/reoxygenation (up to 45 min anoxia). These results indicate that mitochondria are not directly responsible of their oxidative phosphorylation damage observed after in vivo ischemia (K. Willet et al., Transplantation 69 (2000) 582) but are a target of others cellular injuries leading to mitochondrial dysfunction in vivo. [less ▲]

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See detailProton partitioning between ATP synthase and uncoupling protein during cytochrome pathway state 3 respiration in tomato fruit mitochondria
Sluse, Francis ULg; Jarmuszkiewicz, W.; Almeida, A. M. et al

in Hofmeyr, J.; Rohwer, J. M.; Snoops, J. L. (Eds.) Biothermokinetic 2000 : Animating the cellular map (2000)

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See detailEfficiency of Acanthamoeba castellanii uncoupling protein in energy-dissipating processes
Jarmuszkiewicz, W.; Hryniewiecka, L.; Sluse-Goffart, C. et al

in Hofmeyr, J.; Rohwer, J. M.; Snoops, J. L. (Eds.) Biothermokinetic 2000 : Animating the cellular map (2000)

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See detailEffect of pH on CN-resistant respiratory activity and regulation on Vigna uniguiculata mitochondria
Lima-junior, A.; Fernandes de melo, D.; Costa, J. H. et al

in Plant Physiology & Biochemistry (2000), 38

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See detailStress-induced premature senescence. Essence of life, evolution, stress, and aging.
Toussain, O.; Dumont, P.; Dierick, J.-F. et al

in Annals of the New York Academy of Sciences (2000), 908

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See detailProton re-uptake partitioning between uncoupling protein and ATP synthase during benzohydroxamic acid-resistant state 3 respiration in tomato fruit mitochondria.
Jarmuszkiewicz, W.; Almeida, A.; Vercesi, A. et al

in Journal of Biological Chemistry (2000), 275(18), 13315-13320

The yield of oxidative phosphorylation in isolated tomato fruit mitochondria depleted of free fatty acids remains constant when respiratory rates are decreased by a factor of 3 by the addition of n-butyl ... [more ▼]

The yield of oxidative phosphorylation in isolated tomato fruit mitochondria depleted of free fatty acids remains constant when respiratory rates are decreased by a factor of 3 by the addition of n-butyl malonate. This constancy makes the determination of the contribution of the linoleic acid-induced energy-dissipating pathway by the ADP/O method possible. No decrease in membrane potential is observed in state 3 respiration with increasing concentration of n-butyl malonate, indicating that the rate of ATP synthesis is steeply dependent on membrane potential. Linoleic acid decreases the yield of oxidative phosphorylation in a concentration-dependent manner by a pure protonophoric process like that in the presence of FCCP. ADP/O measurements allow calculation of the part of respiration leading to ATP synthesis and the part of respiration sustained by the dissipative H(+) re-uptake induced by linoleic acid. Respiration sustained by this energy-dissipating process remains constant at a given LA concentration until more than 50% inhibition of state 3 respiration by n-butyl malonate is achieved. The energy dissipative contribution to oxygen consumption is proposed to be equal to the protonophoric activity of plant uncoupling protein divided by the intrinsic H(+)/O of the cytochrome pathway. It increases with linoleic acid concentration, taking place at the expense of ADP phosphorylation without an increase in the respiration. [less ▲]

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See detailActivity and functional interaction of alternative oxidase and uncoupling protein in mitochondria from tomato fruit.
Sluse, Francis ULg; Jarmuszkiewicz, W.

in Brazilian Journal of Medical and Biological Research = Revista Brasileira de Pesquisas Medicas e Biologicas (2000), 33

Cyanide-resistant alternative oxidase (AOX) is not limited to plant mitochondria and is widespread among several types of protists. The uncoupling protein (UCP) is much more widespread than previously ... [more ▼]

Cyanide-resistant alternative oxidase (AOX) is not limited to plant mitochondria and is widespread among several types of protists. The uncoupling protein (UCP) is much more widespread than previously believed, not only in tissues of higher animals but also in plants and in an amoeboid protozoan. The redox energy-dissipating pathway (AOX) and the proton electrochemical gradient energy-dissipating pathway (UCP) lead to the same final effect, i.e., a decrease in ATP synthesis and an increase in heat production. Studies with green tomato fruit mitochondria show that both proteins are present simultaneously in the membrane. This raises the question of a specific physiological role for each energy-dissipating system and of a possible functional connection between them (shared regulation). Linoleic acid, an abundant free fatty acid in plants which activates UCP, strongly inhibits cyanide-resistant respiration mediated by AOX. Moreover, studies of the evolution of AOX and UCP protein expression and of their activities during post-harvest ripening of tomato fruit show that AOX and plant UCP work sequentially: AOX activity decreases in early post-growing stages and UCP activity is decreased in late ripening stages. Electron partitioning between the alternative oxidase and the cytochrome pathway as well as H+ gradient partitioning between ATP synthase and UCP can be evaluated by the ADP/O method. This method facilitates description of the kinetics of energy-dissipating pathways and of ATP synthase when state 3 respiration is decreased by limitation of oxidizable substrate. [less ▲]

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See detailIdentification and characterization of a protozoan uncoupling protein in Acanthamoeba castellanii.
Jarmuszkiwicz, W.; Milani, G.; Fortes, F. et al

in FEBS Letters (2000), 467

An uncoupling protein (UCP) was identified in mitochondria from Candida parapsilosis (CpUCP), a non-fermentative parasitic yeast. CpUCP was immunodetected using polyclonal antibodies raised against plant ... [more ▼]

An uncoupling protein (UCP) was identified in mitochondria from Candida parapsilosis (CpUCP), a non-fermentative parasitic yeast. CpUCP was immunodetected using polyclonal antibodies raised against plant UCP. Activity of CpUCP, investigated in mitochondria depleted of free fatty acids, was stimulated by linoleic acid (LA) and inhibited by GTP. Activity of CpUCP enhanced state 4 respiration by decreasing DeltaPsi and lowered the ADP/O ratio. Thus, it was able to divert energy from oxidative phosphorylation. The voltage dependence of electron flux indicated that LA had a pure protonophoretic effect. The discovery of CpUCP proves that UCP-like proteins occur in the four eukaryotic kingdoms: animals, plants, fungi and protists. [less ▲]

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See detailEffects of cold and warm ischemia on the mitochondrial oxidative phosphorylation of swine lung.
Willet, Katty; Detry, Olivier ULg; Lambermont, Bernard ULg et al

in Transplantation (2000), 69(4), 582-588

BACKGROUND: The aim of the study was to investigate the consequence of warm and cold ischemia on lung mitochondria in order to define bioenergetic limits within lung could be suitable for pulmonary ... [more ▼]

BACKGROUND: The aim of the study was to investigate the consequence of warm and cold ischemia on lung mitochondria in order to define bioenergetic limits within lung could be suitable for pulmonary transplantation. METHODS: Twenty-two pigs underwent lung harvesting after lung flush with Euro-Collins solution. Mitochondria were isolated from fresh lungs, from lungs submitted to 24 or 48 hr of cold ischemia, to 30 or 45 min of warm ischemia, and to 30 min of warm ischemia followed by 24 or 48 hr of cold ischemia. Mitochondrial oxidative phosphorylation parameters were determined in isolated mitochondria by in vitro measurement of oxygen consumption. RESULTS: Relative to controls, mitochondria submitted to cold ischemia showed an alteration in the oxidoreductase activities of the respiratory chain but no membrane permeability alteration. After 48 hr of cold ischemia, there was a decrease in the yield of the oxidative phosphorylation. Thirty minutes of warm ischemia did not alter the mitochondrial respiratory parameters. However, lung submitted to 45 min of warm ischemia showed mitochondrial damage as a decrease in the oxidative phosphorylation efficiency and ADP availability but no change in the oxidoreductase activities. Relative to cold ischemia alone, 30 min of warm ischemia preceding cold ischemia promoted no significant change in the respiratory parameters. CONCLUSIONS: On bioenergetic basis, lung submitted to warm ischemia could be suitable for transplantation if the warm ischemia duration does not exceed 30 min. This could be a major concern in lung procurement from non-heart beating donors. [less ▲]

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See detailHuman Muscle Energetics During Voluntary and Electrically Induced Isometric Contractions as Measured by 31p Nmr Spectroscopy
Vanderthommen, Marc ULg; Gilles, R.; Carlier, Pierre ULg et al

in International Journal of Sports Medicine (1999), 20(5), 279-83

Electrical stimulation (ES) and voluntary contraction (VC) were compared in the quadriceps muscle of ten male volunteers. In both modes, a workload corresponding to 20% of maximal voluntary contraction ... [more ▼]

Electrical stimulation (ES) and voluntary contraction (VC) were compared in the quadriceps muscle of ten male volunteers. In both modes, a workload corresponding to 20% of maximal voluntary contraction was applied during 64 isometric contraction (5.5 s)-relaxation (5.5 s) cycles. The protocols were performed in a 1.5 T whole-body magnet. The Pi/PCr ratio and the intracellular pH (pHi) were monitored by 31P NMR spectroscopy during baseline, exercise and recovery periods, in a superficial region of the vastus medialis. During baseline, the Pi/PCr ratio (0.12 vs. 0.10) and the pHi (7.01 vs. 7.00) were comparable in both conditions. During exercise, the Pi/PCr ratio was higher (0.36 vs. 0.14) and the pHi was lower (6.85 vs. 7.07) during ES than during VC. For the same external work production, these results reflect a different metabolic solicitation in the ES quadriceps than in the VC ones. [less ▲]

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See detailImplication des propriétés biomécaniques des muscles transformés dans le mécanisme de la cardiomyoplastie
Radermacker, M. A.; Sluse, Francis ULg; Focant, B. et al

in Journal of Cardiology (1999), 9

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