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Kavalenia TA, Lapshina EA, Ilyich TV, Zhao HC, Zavodnik IB. Functional activity and morphology of isolated rat cardiac mitochondria under calcium overload. Effect of naringin. Mol Cell Biochem 2024:10.1007/s11010-024-04935-z. [PMID: 38332449 DOI: 10.1007/s11010-024-04935-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 01/08/2024] [Indexed: 02/10/2024]
Abstract
The function of mitochondria as a regulator of myocyte calcium homeostasis has been extensively discussed. The aim of the present work was further clarification of the details of modulation of the functional activity of rat cardiac mitochondria by exogenous Ca2+ ions either in the absence or in the presence of the plant flavonoid naringin. Low free Ca2+ concentrations (40-250 nM) effectively inhibited the respiratory activity of heart mitochondria, remaining unaffected the efficacy of oxygen consumption. In the presence of high exogenous Ca2+ ion concentrations (Ca2+ free was 550 µM), we observed a dramatic increase in mitochondrial heterogeneity in size and electron density, which was related to calcium-induced opening of the mitochondrial permeability transition pores (MPTP) and membrane depolarization (Ca2+free ions were from 150 to 750 µM). Naringin partially prevented Ca2+-induced cardiac mitochondrial morphological transformations (200 µM) and dose-dependently inhibited the respiratory activity of mitochondria (10-75 µM) in the absence or in the presence of calcium ions. Our data suggest that naringin (75 µM) promoted membrane potential dissipation, diminishing the potential-dependent accumulation of calcium ions by mitochondria and inhibiting calcium-induced MPTP formation. The modulating effect of the flavonoid on Ca2+-induced mitochondria alterations may be attributed to the weak-acidic nature of the flavonoid and its protonophoric/ionophoric properties. Our results show that the sensitivity of rat heart mitochondria to Ca2+ ions was much lower in the case of MPTP opening and much higher in the case of respiration inhibition as compared to liver mitochondria.
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Affiliation(s)
- T A Kavalenia
- Department of Biochemistry, Yanka Kupala State University of Grodno, Bulvar Leninskogo Komsomola, 5, 230009, Grodno, Belarus
| | - E A Lapshina
- Department of Biochemistry, Yanka Kupala State University of Grodno, Bulvar Leninskogo Komsomola, 5, 230009, Grodno, Belarus
| | - T V Ilyich
- Department of Biochemistry, Yanka Kupala State University of Grodno, Bulvar Leninskogo Komsomola, 5, 230009, Grodno, Belarus
| | - Hu-Cheng Zhao
- Institute of Biomechanics and Medical Engineering, Tsinghua University, Beijing, 100084, People's Republic of China
| | - I B Zavodnik
- Department of Biochemistry, Yanka Kupala State University of Grodno, Bulvar Leninskogo Komsomola, 5, 230009, Grodno, Belarus.
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2
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Khan K, Tran HC, Mansuroglu B, Önsell P, Buratti S, Schwarzländer M, Costa A, Rasmusson AG, Van Aken O. Mitochondria-derived reactive oxygen species are the likely primary trigger of mitochondrial retrograde signaling in Arabidopsis. Curr Biol 2024; 34:327-342.e4. [PMID: 38176418 DOI: 10.1016/j.cub.2023.12.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 10/28/2023] [Accepted: 12/04/2023] [Indexed: 01/06/2024]
Abstract
Besides their central function in respiration, plant mitochondria play a crucial role in maintaining cellular homeostasis during stress by providing "retrograde" feedback to the nucleus. Despite the growing understanding of this signaling network, the nature of the signals that initiate mitochondrial retrograde regulation (MRR) in plants remains unknown. Here, we investigated the dynamics and causative relationship of a wide range of mitochondria-related parameters for MRR, using a combination of Arabidopsis fluorescent protein biosensor lines, in vitro assays, and genetic and pharmacological approaches. We show that previously linked physiological parameters, including changes in cytosolic ATP, NADH/NAD+ ratio, cytosolic reactive oxygen species (ROS), pH, free Ca2+, and mitochondrial membrane potential, may often be correlated with-but are not the primary drivers of-MRR induction in plants. However, we demonstrate that the induced production of mitochondrial ROS is the likely primary trigger for MRR induction in Arabidopsis. Furthermore, we demonstrate that mitochondrial ROS-mediated signaling uses the ER-localized ANAC017-pathway to induce MRR response. Finally, our data suggest that mitochondrially generated ROS can induce MRR without substantially leaking into other cellular compartments such as the cytosol or ER lumen, as previously proposed. Overall, our results offer compelling evidence that mitochondrial ROS elevation is the likely trigger of MRR.
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Affiliation(s)
- Kasim Khan
- Department of Biology, Lund University, Sölvegatan 35, Lund 223 62, Sweden
| | - Huy Cuong Tran
- Department of Biology, Lund University, Sölvegatan 35, Lund 223 62, Sweden
| | - Berivan Mansuroglu
- Department of Biology, Lund University, Sölvegatan 35, Lund 223 62, Sweden
| | - Pinar Önsell
- Department of Biology, Lund University, Sölvegatan 35, Lund 223 62, Sweden
| | - Stefano Buratti
- Department of Biosciences, University of Milan, Via G. Celoria 26, Milan 20133, Italy
| | - Markus Schwarzländer
- Plant Energy Biology Lab, Institute of Plant Biology and Biotechnology, University of Münster, Schlossplatz 8, 48143 Münster, Germany
| | - Alex Costa
- Department of Biosciences, University of Milan, Via G. Celoria 26, Milan 20133, Italy; Institute of Biophysics, Consiglio Nazionale delle Ricerche, Via G. Celoria 26, 20133 Milan, Italy
| | - Allan G Rasmusson
- Department of Biology, Lund University, Sölvegatan 35, Lund 223 62, Sweden
| | - Olivier Van Aken
- Department of Biology, Lund University, Sölvegatan 35, Lund 223 62, Sweden.
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3
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Ocampo-Hernández B, Gutiérrez Mireles ER, Gutiérrez-Aguilar M. Morphology and permeability transitions in plant mitochondria: Different aspects of the same event? BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2022; 1863:148586. [PMID: 35772521 DOI: 10.1016/j.bbabio.2022.148586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 06/22/2022] [Accepted: 06/23/2022] [Indexed: 06/15/2023]
Abstract
Plant mitochondria are sensitive organelles affected by changing environmental stressors. Upon heat shock or the presence of reactive oxygen species, plant mitochondria undergo in vivo morphological derangements associated with the extensively characterized opening of the mitochondrial permeability transition pore. Nevertheless, the classic mitochondrial permeability transition is known to be triggered by calcium overload causing mitochondrial swelling and dysfunction. Here we review evidence concerning calcium handling, permeability transition and mitochondrial impairments in plants, supporting the notion that the mitochondrial morphology transition is an in vivo indicator of the permeability transition.
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Affiliation(s)
- Bryan Ocampo-Hernández
- Departamento de Bioquímica, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510 México City, México
| | - Emilia R Gutiérrez Mireles
- Departamento de Bioquímica, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510 México City, México
| | - Manuel Gutiérrez-Aguilar
- Departamento de Bioquímica, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510 México City, México.
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Anthocyanin-Rich Extract of Red Cabbage Attenuates Advanced Alcohol Hepatotoxicity in Rats in Association with Mitochondrial Activity Modulation. EUROPEAN PHARMACEUTICAL JOURNAL 2022. [DOI: 10.2478/afpuc-2022-0014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
Aim
The liver is the main target for alcohol-induced injury. The aims of this work were to carry out further research into the mechanisms of liver damage induced by long-term administration of high-dose ethanol to rats and to evaluate the hepatoprotective potential of red cabbage (Brassica oleracea var. capitata f. rubra) anthocyanins (RCE).
Material/Methods
Male albino Wistar rats were divided into four groups. Group 1 was the control. Groups 2 through 4 received ethanol (4 g/kg body weight, 8 weeks). Group 3 received 11 mg RCE/kg and Group 4 received 22 mg RCE/kg. Dry lyophilised RCE was prepared from fresh red cabbage and analysed. We then evaluated the liver histology, mitochondrial respiration, and biochemical and immunological parameters in these groups of rats.
Results
The rat intoxication caused steatohepatitis characterised by macro- and microvesicular steatosis, ballooning and fatty liver dystrophies, lymphocytic infiltration, neutral lipid accumulation, and elevations of the serum activities of the liver injury marker enzymes. The treatment of alcohol-administered rats with RCE (mainly, cyanidin-3-diglucoside-5-glucoside, cyanidin-3-coumaroylrutinoside-5-hexoside, cyanidin-3-feruloylrutinoside-5-hexoside, delphinidin-3-feruloylrutinoside-hexoside) dose-dependently alleviated these pathological changes: The sizes of hepatocyte lipid vacuoles and the inflammatory signs were decreased, and the levels of the rat serum biochemical markers of liver injury, proinflammatory cytokines TNFα and IL-6, and the adipokine leptin (and not TGFβ) were significantly reversed. The RCE administration during intoxication completely recovered the changed liver mitochondria respiration rates and the ADP/O coefficient, as well as the phagocytic index and neutrophil metabolic activity in the blood. In experiments in vitro, RCE (13.6 μg/ml) modulated the respiratory parameters of isolated rat liver mitochondria, dissipated mitochondrial membrane potential, and inhibited the Ca2+-induced mitochondrial permeability transition.
Conclusion
The red cabbage anthocyanins could be useful for treatment of alcoholic liver injury due to their Ca2+-ionophoric/protonophoric activity, influence on Ca2+ homeostasis, and improving mitochondrial functions and inflammatory status.
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Studies of the Formation and Stability of Ezetimibe-Cyclodextrin Inclusion Complexes. Int J Mol Sci 2021; 23:ijms23010455. [PMID: 35008881 PMCID: PMC8745117 DOI: 10.3390/ijms23010455] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 12/27/2021] [Accepted: 12/28/2021] [Indexed: 12/27/2022] Open
Abstract
In the presented studies, the interactions between ezetimibe (EZE) and selected cyclodextrins were investigated. α-Cyclodextrin (αCD), β-cyclodextrin (βCD) and its modified derivatives, hydroxypropyl-β-cyclodextrin (HPβCD) and sulfobutylether-β-cyclodextrin (SBEβCD), were selected for the research. Measurements were carried out using calorimetric and spectroscopic methods. Additionally, the Hirshfeld surface and biochemical analysis were achieved. As a result of the study, the inclusion complexes with 1:1 stoichiometry were obtained. The most stable are the complexes of β-cyclodextrin and its derivatives. The comparison of βCD with its derivatives shows that the modifications have an affect on the formation of more durable and stable complexes.
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Cheshchevik VT, Krylova NG, Сheshchevik NG, Lapshina EA, Semenkova GN, Zavodnik IB. Role of mitochondrial calcium in hypochlorite induced oxidative damage of cells. Biochimie 2021; 184:104-115. [PMID: 33607241 DOI: 10.1016/j.biochi.2021.02.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 01/09/2021] [Accepted: 02/10/2021] [Indexed: 11/29/2022]
Abstract
Hypochlorite (HOCl) is one of the most important mediators of inflammatory processes. Recent evidence demonstrates that changes in intracellular calcium pool play a significant role in the damaging effects of hypochlorite and other oxidants. Mitochondria are shown to be one of the intracellular targets of hypochlorite. But little is known about the mitochondrial calcium pool changes in HOCl-induced mitochondrial dysfunction. Using isolated rat liver mitochondria, we showed the oxidative damage of mitochondria (GSH oxidation and mixed protein-glutathione formation without membrane lipid peroxidation) and alterations in the mitochondrial functional parameters (decrease of respiratory activity and efficiency of oxidative phosphorylation, NADH and FADH coenzyme levels, and membrane potential) under hypochlorite action (50-300 μM). Simultaneously, the mitochondrial calcium release and swelling were demonstrated. In the presence of EGTA, the damaging effects of HOCl were less pronounced, reflecting direct involvement of mitochondrial Ca2+ in mechanisms of oxidant-induced injury. Furthermore, exposure of HeLa cells to hypochlorite resulted in a considerable increase in cytoplasmic calcium concentrations and a decrease in mitochondrial ones. Applying specific inhibitors of calcium transfer systems, we demonstrated that mitochondria play a key role in the redistribution of cytoplasmic Ca2+ ions under hypochlorite action and act as mediators of calcium release from the endoplasmic reticulum into the cytoplasm.
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Affiliation(s)
- Vitali T Cheshchevik
- Department of Biotechnology, Polessky State University, ulitsa Dnieprovskoy Flotilii, 23, 225710, Pinsk, Belarus.
| | - Nina G Krylova
- Department of Biophysics, Belarusian State University, Prospekt Nezavisimosti 4, 220030, Minsk, Belarus
| | - Nina G Сheshchevik
- Department of Biotechnology, Polessky State University, ulitsa Dnieprovskoy Flotilii, 23, 225710, Pinsk, Belarus
| | - Elena A Lapshina
- Department of Biochemistry, Yanka Kupala State University of Grodno, Bulvar Leninskogo Komsomola 50, 230030, Grodno, Belarus
| | - Galina N Semenkova
- Department of Biophysics, Belarusian State University, Prospekt Nezavisimosti 4, 220030, Minsk, Belarus
| | - Ilya B Zavodnik
- Department of Biochemistry, Yanka Kupala State University of Grodno, Bulvar Leninskogo Komsomola 50, 230030, Grodno, Belarus
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Bioenergetic consequences from xenotopic expression of a tunicate AOX in mouse mitochondria: Switch from RET and ROS to FET. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2020; 1861:148137. [PMID: 31825809 DOI: 10.1016/j.bbabio.2019.148137] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 12/01/2019] [Accepted: 12/05/2019] [Indexed: 12/23/2022]
Abstract
Electron transfer from all respiratory chain dehydrogenases of the electron transport chain (ETC) converges at the level of the quinone (Q) pool. The Q redox state is thus a function of electron input (reduction) and output (oxidation) and closely reflects the mitochondrial respiratory state. Disruption of electron flux at the level of the cytochrome bc1 complex (cIII) or cytochrome c oxidase (cIV) shifts the Q redox poise to a more reduced state which is generally sensed as respiratory stress. To cope with respiratory stress, many species, but not insects and vertebrates, express alternative oxidase (AOX) which acts as an electron sink for reduced Q and by-passes cIII and cIV. Here, we used Ciona intestinalis AOX xenotopically expressed in mouse mitochondria to study how respiratory states impact the Q poise and how AOX may be used to restore respiration. Particularly interesting is our finding that electron input through succinate dehydrogenase (cII), but not NADH:ubiquinone oxidoreductase (cI), reduces the Q pool almost entirely (>90%) irrespective of the respiratory state. AOX enhances the forward electron transport (FET) from cII thereby decreasing reverse electron transport (RET) and ROS specifically when non-phosphorylating. AOX is not engaged with cI substrates, however, unless a respiratory inhibitor is added. This sheds new light on Q poise signaling, the biological role of cII which enigmatically is the only ETC complex absent from respiratory supercomplexes but yet participates in the tricarboxylic acid (TCA) cycle. Finally, we delineate potential risks and benefits arising from therapeutic AOX transfer.
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Belosludtsev KN, Belosludtseva NV, Tenkov KS, Sharapov VA, Kosareva EA, Dubinin MV. Effect of Dequalinium on Respiration and the Inner Membrane Permeability of Rat Liver Mitochondria. BIOCHEMISTRY (MOSCOW), SUPPLEMENT SERIES A: MEMBRANE AND CELL BIOLOGY 2018; 12:121-127. [DOI: 10.1134/s1990747818020034] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 06/20/2017] [Indexed: 11/29/2023]
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Ilyich T, Charishnikova O, Sekowski S, Zamaraeva M, Cheshchevik V, Dremza I, Cheshchevik N, Kiryukhina L, Lapshina E, Zavodnik I. Ferutinin Induces Membrane Depolarization, Permeability Transition Pore Formation, and Respiration Uncoupling in Isolated Rat Liver Mitochondria by Stimulation of Ca 2+-Permeability. J Membr Biol 2018; 251:563-572. [PMID: 29594529 DOI: 10.1007/s00232-018-0032-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 03/24/2018] [Indexed: 01/17/2023]
Abstract
It is well known that the terpenoid ferutinin (4-oxy-6-(4-oxybenzoyloxy) dauc-8,9-en), isolated from the plant Ferula tenuisecta, considerably increases the permeability of artificial and cellular membranes to Ca2+-ions and produces apoptotic cell death in different cell lines in a mitochondria-dependent manner. The present study was designed for further evaluation of the mechanism(s) of mitochondrial effects of ferutinin using isolated rat liver mitochondria. Our findings provide evidence for ferutinin at concentrations of 5-27 µM to decrease state 3 respiration and the acceptor control ratio in the case of glutamate/malate as substrates. Ferutinin alone (10-60 µM) also dose-dependently dissipated membrane potential. In the presence of Ca2+-ions, ferutinin (10-60 µM) induced considerable depolarization of the inner mitochondrial membrane, which was partially inhibited by EGTA, and permeability transition pore formation, which was diminished partly by cyclosporin A, and did not influence markedly the effect of Ca2+ on mitochondrial respiration. Ruthenium Red, a specific inhibitor of mitochondrial calcium uniporter, completely inhibited Ca2+-induced mitochondria swelling and membrane depolarization, but did not affect markedly the stimulation of these Ca2+-dependent processes by ferutinin. We concluded that the mitochondrial effects of ferutinin might be primarily induced by stimulation of mitochondrial membrane Ca2+-permeability, but other mechanisms, such as driving of univalent cations, might be involved.
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Affiliation(s)
- Tatsiana Ilyich
- Department of Biochemistry, Yanka Kupala State University of Grodno, Blvd. Len. Kom. - 50, 230030, Grodno, Belarus
| | - Oksana Charishnikova
- National University of Uzbekistan named after Mirzo Ulugbek, Vuzgorodok, 700174, Tashkent, Uzbekistan
| | - Szymon Sekowski
- Department of Biophysics, University of Bialystok, Ciolkowskiego 1J, 15-245, Bialystok, Poland
| | - Maria Zamaraeva
- Department of Biophysics, University of Bialystok, Ciolkowskiego 1J, 15-245, Bialystok, Poland
| | - Vitali Cheshchevik
- Department of Biotechnology, Polessky State University, Dnieprovskoy Flotilii, 23, 225710, Pinsk, Brest Region, Belarus
| | - Iosif Dremza
- Department of Pathophysiology, State Medical University of Grodno, Gorkogo, 80, 230015, Grodno, Belarus
| | - Nina Cheshchevik
- Department of Biotechnology, Polessky State University, Dnieprovskoy Flotilii, 23, 225710, Pinsk, Brest Region, Belarus
| | - Lyudmila Kiryukhina
- Department of Biochemistry, Yanka Kupala State University of Grodno, Blvd. Len. Kom. - 50, 230030, Grodno, Belarus
| | - Elena Lapshina
- Department of Biochemistry, Yanka Kupala State University of Grodno, Blvd. Len. Kom. - 50, 230030, Grodno, Belarus
| | - Ilya Zavodnik
- Department of Biochemistry, Yanka Kupala State University of Grodno, Blvd. Len. Kom. - 50, 230030, Grodno, Belarus.
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Golovach NG, Cheshchevik VT, Lapshina EA, Ilyich TV, Zavodnik IB. Calcium-Induced Mitochondrial Permeability Transitions: Parameters of Ca 2+ Ion Interactions with Mitochondria and Effects of Oxidative Agents. J Membr Biol 2017; 250:225-236. [PMID: 28251264 DOI: 10.1007/s00232-017-9953-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 02/21/2017] [Indexed: 12/13/2022]
Abstract
We evaluated the parameters of Ca2+-induced mitochondrial permeability transition (MPT) pore formations, Ca2+ binding constants, stoichiometry, energy of activation, and the effect of oxidative agents, tert-butyl hydroperoxide (tBHP), and hypochlorous acid (HOCl), on Ca2+ -mediated process in rat liver mitochondria. From the Hill plot of the dependence of MPT rate on Ca2+ concentration, we determined the order of interaction of Ca2+ ions with the mitochondrial sites, n = 3, and the apparent Kd = 60 ± 12 µM. We also found the apparent Michaelis-Menten constant, Km, for Ca2+ interactions with mitochondria to be equal to 75 ± 20 µM, whereas that in the presence of 300 µM tBHP was 120 ± 20 µM. Using the Arrhenius plots of the temperature dependences of apparent mitochondrial swelling rate at various Ca2+ concentrations, we calculated the activation energy of the MPT process. ΔEa was 130 ± 20 kJ/mol at temperatures below the break point of the Arrhenius plot (30-34 °C) and 50 ± 9 kJ/mol at higher temperatures. Ca2+ ions induced rapid mitochondrial NADH depletion and membrane depolarization. Prevention of the pore formation by cyclosporin A inhibited Ca2+-dependent mitochondrial depolarization and Mg2+ ions attenuated the potential dissipation. tBHP (10-150 µM) dose-dependently enhanced the rate of MPT opening, whereas the effect of HOCl on MPT depended on the ratio of HOCl/Ca2+. The apparent Km of tBHP interaction with mitochondria in the swelling reaction was found to be Km = 11 ± 3 µM. The present study provides evidence that three calcium ions interact with mitochondrial site with high affinity during MPT. Ca2+-induced MPT pore formations due to mitochondrial membrane protein denaturation resulted in membrane potential dissipation. Oxidants with different mechanisms, tBHP and HOCl, reduced mitochondrial membrane potential and oxidized mitochondrial NADH in EDTA-free medium and had an effect on Ca2+-induced MPT onset.
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Affiliation(s)
- Nina G Golovach
- Department of Biochemistry, Yanka Kupala State University of Grodno, Blvd. Len. Kom. - 50, 230030, Grodno, Belarus
| | - Vitali T Cheshchevik
- Department of Biochemistry, Yanka Kupala State University of Grodno, Blvd. Len. Kom. - 50, 230030, Grodno, Belarus
| | - Elena A Lapshina
- Department of Biochemistry, Yanka Kupala State University of Grodno, Blvd. Len. Kom. - 50, 230030, Grodno, Belarus
| | - Tatsiana V Ilyich
- Department of Biochemistry, Yanka Kupala State University of Grodno, Blvd. Len. Kom. - 50, 230030, Grodno, Belarus
| | - Ilya B Zavodnik
- Department of Biochemistry, Yanka Kupala State University of Grodno, Blvd. Len. Kom. - 50, 230030, Grodno, Belarus.
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Белослудцев К, Белослудцева Н, Теньков КС, Шарапов ВА, Косарева ЕА, Дубинин М. ВЛИЯНИЕ ДЕКВАЛИНИУМА НА ДЫХАНИЕ И?ПРОНИЦАЕМОСТЬ ВНУТРЕННЕЙ МЕМБРАНЫ МИТОХОНДРИЙ ПЕЧЕНИ КРЫС, "Биологические мембраны: Журнал мембранной и клеточной биологии". БИОЛОГИЧЕСКИЕ МЕМБРАНЫ: ЖУРНАЛ МЕМБРАННОЙ И КЛЕТОЧНОЙ БИОЛОГИИ 2017:101-108. [DOI: 10.7868/s0233475517060032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
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12
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Krylova NG, Kulahava TA, Cheschevik VT, Dremza IK, Semenkova GN, Zavodnik IB. Redox regulation of mitochondrial functional activity by quinones. Physiol Int 2016; 103:439-458. [DOI: 10.1556/2060.103.2016.4.4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Quinones are among the rare compounds successfully used as therapeutic agents to correct mitochondrial diseases and as specific regulators of mitochondrial function within cells. The aim of the present study was to elucidate the redox-dependent effects of quinones on mitochondrial function. The functional parameters [respiratory activity, membrane potential, and reactive oxygen species (ROS) generation] of isolated rat liver mitochondria and mitochondria in intact cells were measured in the presence of eight exogenously applied quinones that differ in lipophilicity and one-electron reduction potential. The quinones affected the respiratory parameters of mitochondria, and dissipated the mitochondrial membrane potential as well as influenced (either decreased or enhanced) ROS generation, and restored the electron flow during electron transport chain inhibition. The stimulation of ROS production by juglone and 2,5-di-tert-butyl-1,4-benzoquinone was accompanied by a decrease in the acceptor control and respiration control ratios, dissipation of the mitochondrial membrane potential and induction of the reverse electron flow under succinate oxidation in isolated mitochondria. Menadione and 2,3,5-trimethyl-1,4-benzoquinone, which decreased the mitochondrial ROS generation, did not affect the mitochondrial potential and, vice versa, were capable of restoring electron transport during Complex I inhibition. In intact C6 cells, all the quinones, except for coenzyme Q10, decreased the mitochondrial membrane potential. Juglone, 1,4-benzoquinone, and menadione showed the most pronounced effects. These findings indicate that quinones with the reduction potential values E1/2 in the range from −99 to −260 mV were effective redox regulators of mitochondrial electron transport.
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Affiliation(s)
- NG Krylova
- 1 Department of Biophysics, Faculty of Physics, Belarusian State University, Minsk, Belarus
| | - TA Kulahava
- 1 Department of Biophysics, Faculty of Physics, Belarusian State University, Minsk, Belarus
| | - VT Cheschevik
- 2 Department of Biochemistry, Yanka Kupala State University of Grodno, Grodno, Belarus
| | - IK Dremza
- 2 Department of Biochemistry, Yanka Kupala State University of Grodno, Grodno, Belarus
| | - GN Semenkova
- 3 Department of Radiation Chemistry and Pharmaceutical Technologies, Faculty of Chemistry, Belarusian State University, Minsk, Belarus
| | - IB Zavodnik
- 2 Department of Biochemistry, Yanka Kupala State University of Grodno, Grodno, Belarus
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Sayed MA, Umekawa Y, Ito K. Metabolic interplay between cytosolic phosphoenolpyruvate carboxylase and mitochondrial alternative oxidase in thermogenic skunk cabbage, Symplocarpus renifolius. PLANT SIGNALING & BEHAVIOR 2016; 11:e1247138. [PMID: 27739913 PMCID: PMC5157899 DOI: 10.1080/15592324.2016.1247138] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 10/05/2016] [Accepted: 10/05/2016] [Indexed: 06/06/2023]
Abstract
Skunk cabbage (Symplocarpus renifolius) blooms in early spring and its inflorescence, referred to as the spadix, can produce enough heat to melt snow. Here, we investigated glycolytic carbon flow at the PEP branch-point in thermogenic spadices. Our analyses revealed that petals and pistils in thermogenic florets exhibited higher expression of SrPEPC and SrAOX transcripts than those of SrPK, SrPEPCK, and SrPEPtase. Moreover, enzymatic analyses showed high activities of PEPC in the extracts from thermogenic florets. Finally, mitochondria from thermogenic florets showed low respiratory activities when pyruvate was used as a substrate, although a significant malate-mediated cyanide-insensitive respiration was observed. Collectively, these results suggest that PEP metabolism, primarily catabolized by PEPC, plays a critical role in thermogenesis in S. renifolius.
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Affiliation(s)
- Md. Abu Sayed
- United Graduate School of Agricultural Science, Iwate University, Ueda, Morioka, Iwate, Japan
| | - Yui Umekawa
- United Graduate School of Agricultural Science, Iwate University, Ueda, Morioka, Iwate, Japan
| | - Kikukatsu Ito
- United Graduate School of Agricultural Science, Iwate University, Ueda, Morioka, Iwate, Japan
- Cryobiofrontier Research Center, Faculty of Agriculture, Iwate University, Ueda, Morioka, Iwate, Japan
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14
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Nogales A, Nobre T, Cardoso HG, Muñoz-Sanhueza L, Valadas V, Campos MD, Arnholdt-Schmitt B. Allelic variation on DcAOX1 gene in carrot (Daucus carota L.): An interesting simple sequence repeat in a highly variable intron. ACTA ACUST UNITED AC 2016. [DOI: 10.1016/j.plgene.2015.11.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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15
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Cabrera-Orefice A, Ibarra-García-Padilla R, Maldonado-Guzmán R, Guerrero-Castillo S, Luévano-Martínez LA, Pérez-Vázquez V, Gutiérrez-Aguilar M, Uribe-Carvajal S. The Saccharomyces cerevisiae mitochondrial unselective channel behaves as a physiological uncoupling system regulated by Ca2+, Mg2+, phosphate and ATP. J Bioenerg Biomembr 2015; 47:477-91. [PMID: 26530988 DOI: 10.1007/s10863-015-9632-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 10/23/2015] [Indexed: 02/07/2023]
Abstract
It is proposed that the Saccharomyces cerevisiae the Mitochondrial Unselective Channel ((Sc)MUC) is tightly regulated constituting a physiological uncoupling system that prevents overproduction of reactive oxygen species (ROS). Mg(2+), Ca(2+) or phosphate (Pi) close (Sc)MUC, while ATP or a high rate of oxygen consumption open it. We assessed (Sc)MUC activity by measuring in isolated mitochondria the respiratory control, transmembrane potential (ΔΨ), swelling and production of ROS. At increasing [Pi], less [Ca(2+)] and/or [Mg(2+)] were needed to close (Sc)MUC or increase ATP synthesis. The Ca(2+)-mediated closure of (Sc)MUC was prevented by high [ATP] while the Mg(2+) or Pi effect was not. When Ca(2+) and Mg(2+) were alternatively added or chelated, (Sc)MUC opened and closed reversibly. Different effects of Ca(2+) vs Mg(2+) effects were probably due to mitochondrial Mg(2+) uptake. Our results suggest that (Sc)MUC activity is dynamically controlled by both the ATP/Pi ratio and divalent cation fluctuations. It is proposed that the reversible opening/closing of (Sc)MUC leads to physiological uncoupling and a consequent decrease in ROS production.
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Affiliation(s)
- Alfredo Cabrera-Orefice
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Rodrigo Ibarra-García-Padilla
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Rocío Maldonado-Guzmán
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | | | - Luis A Luévano-Martínez
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP, Brazil
| | | | | | - Salvador Uribe-Carvajal
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico. .,Salvador Uribe-Carvajal, Department of Molecular Genetics, Instituto de Fisiología Celular, UNAM, Apdo. postal 70-242, 04510, Mexico City, Mexico.
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16
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Trono D, Laus MN, Soccio M, Pastore D. Transport pathways--proton motive force interrelationship in durum wheat mitochondria. Int J Mol Sci 2014; 15:8186-215. [PMID: 24821541 PMCID: PMC4057727 DOI: 10.3390/ijms15058186] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Revised: 04/18/2014] [Accepted: 04/24/2014] [Indexed: 12/25/2022] Open
Abstract
In durum wheat mitochondria (DWM) the ATP-inhibited plant mitochondrial potassium channel (PmitoK(ATP)) and the plant uncoupling protein (PUCP) are able to strongly reduce the proton motive force (pmf) to control mitochondrial production of reactive oxygen species; under these conditions, mitochondrial carriers lack the driving force for transport and should be inactive. However, unexpectedly, DWM uncoupling by PmitoK(ATP) neither impairs the exchange of ADP for ATP nor blocks the inward transport of Pi and succinate. This uptake may occur via the plant inner membrane anion channel (PIMAC), which is physiologically inhibited by membrane potential, but unlocks its activity in de-energized mitochondria. Probably, cooperation between PIMAC and carriers may accomplish metabolite movement across the inner membrane under both energized and de-energized conditions. PIMAC may also cooperate with PmitoK(ATP) to transport ammonium salts in DWM. Interestingly, this finding may trouble classical interpretation of in vitro mitochondrial swelling; instead of free passage of ammonia through the inner membrane and proton symport with Pi, that trigger metabolite movements via carriers, transport of ammonium via PmitoK(ATP) and that of the counteranion via PIMAC may occur. Here, we review properties, modulation and function of the above reported DWM channels and carriers to shed new light on the control that they exert on pmf and vice-versa.
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Affiliation(s)
- Daniela Trono
- Consiglio per la Ricerca e la sperimentazione in Agricoltura, Centro di Ricerca per la Cerealicoltura, S.S. 673 Km 25, 71122 Foggia, Italy.
| | - Maura N Laus
- Dipartimento di Scienze Agrarie, degli Alimenti e dell'Ambiente, Università di Foggia, Via Napoli 25, 71122 Foggia, Italy.
| | - Mario Soccio
- Dipartimento di Scienze Agrarie, degli Alimenti e dell'Ambiente, Università di Foggia, Via Napoli 25, 71122 Foggia, Italy.
| | - Donato Pastore
- Dipartimento di Scienze Agrarie, degli Alimenti e dell'Ambiente, Università di Foggia, Via Napoli 25, 71122 Foggia, Italy.
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17
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Mitochondrial involvement to methylglyoxal detoxification: D-Lactate/Malate antiporter in Saccharomyces cerevisiae. Antonie van Leeuwenhoek 2012; 102:163-75. [PMID: 22460278 DOI: 10.1007/s10482-012-9724-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Accepted: 03/14/2012] [Indexed: 12/11/2022]
Abstract
Research during the last years has accumulated a large body of data that suggest that a permanent high flux through the glycolytic pathway may be a source of intracellular toxicity via continuous generation of endogenous reactive dicarbonyl compound methylglyoxal (MG). MG detoxification by the action of the glyoxalase system produces D-lactate. Thus, this article extends our previous work and presents new insights concerning D-lactate fate in aerobically grown yeast cells. Biochemical studies using intact functional mitochondrial preparations derived from Saccharomyces cerevisiae show that D-lactate produced in the extramitochondrial phase can be taken up by mitochondria, metabolised inside the organelles with efflux of newly synthesized malate. Experiments were carried out photometrically and the rate of malate efflux was measured by use of NADP(+) and malic enzyme and it depended on the rate of transport across the mitochondrial membrane. It showed saturation characteristics (K(m) = 20 μM; V(max) = 6 nmol min(-1) mg(-1) of mitochondrial protein) and was inhibited by α-cyanocinnamate, a non-penetrant compound. Our data reveal that reducing equivalents export from mitochondria is due to the occurrence of a putative D-lactate/malate antiporter which differs from both D-lactate/pyruvate antiporter and D-lactate/H(+) symporter as shown by the different V(max) values, pH profile and inhibitor sensitivity. Based on these results we propose that D-lactate translocators and D-lactate dehydrogenases work together for decreasing the production of MG from the cytosol, thus mitochondria could play a pro-survival role in the metabolic stress response as well as for D-lactate-dependent gluconeogenesis.
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18
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Trono D, Soccio M, Laus MN, Pastore D. Potassium channel-oxidative phosphorylation relationship in durum wheat mitochondria from control and hyperosmotic-stressed seedlings. PLANT, CELL & ENVIRONMENT 2011; 34:2093-108. [PMID: 21819416 DOI: 10.1111/j.1365-3040.2011.02407.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Durum wheat mitochondria (DWM) possess an ATP-inhibited K(+) channel, the plant mitoK(ATP) (PmitoK(ATP) ), which is activated under environmental stress to control mitochondrial ROS production. To do this, PmitoK(ATP) collapses membrane potential (ΔΨ), thus suggesting mitochondrial uncoupling. We tested this point by studying oxidative phosphorylation (OXPHOS) in DWM purified from control seedlings and from seedlings subjected both to severe mannitol and NaCl stress. In severely-stressed DWM, the ATP synthesis via OXPHOS, continuously monitored by a spectrophotometric assay, was about 90% inhibited when the PmitoK(ATP) was activated by KCl. Contrarily, in control DWM, although PmitoK(ATP) collapsed ΔΨ, ATP synthesis, as well as coupling [respiratory control (RC) ratio and ratio between phosphorylated ADP and reduced oxygen (ADP/O)] checked by oxygen uptake experiments, were unaffected. We suggest that PmitoK(ATP) may play an important defensive role at the onset of the environmental/oxidative stress by preserving energy in a crucial moment for cell and mitochondrial bioenergetics. Consistently, under moderate mannitol stress, miming an early stress condition, the channel may efficiently control reactive oxygen species (ROS) generation (about 35-fold from fully open to closed state) without impairing ATP synthesis. Anyway, if the stress significantly proceeds, the PmitoK(ATP) becomes fully activated by decrease of ATP concentration (25-40%) and increase of activators [free fatty acids (FFAs) and superoxide anion], thus impairing ATP synthesis.
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Affiliation(s)
- Daniela Trono
- CRA - Centro di Ricerca per la Cerealicoltura, S.S. 16 Km 675, Dipartimento di Scienze Agroambientali, Chimica e Difesa Vegetale, Università di Foggia, Via Napoli 25, Italy
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19
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Di Martino C, Pallotta ML. Mitochondria-localized NAD biosynthesis by nicotinamide mononucleotide adenylyltransferase in Jerusalem artichoke (Helianthus tuberosus L.) heterotrophic tissues. PLANTA 2011; 234:657-670. [PMID: 21598001 DOI: 10.1007/s00425-011-1428-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Accepted: 04/30/2011] [Indexed: 05/30/2023]
Abstract
Current studies in plants suggest that the content of the coenzyme NAD is variable and potentially important in determining cell fate. In cases that implicate NAD consumption, re-synthesis must occur to maintain dinucleotide pools. Despite information on the pathways involved in NAD synthesis in plants, the existence of a mitochondrial nicotinamide mononucleotide adenylyltransferase (NMNAT) activity which catalyses NAD synthesis from nicotinamide mononucleotide (NMN) and ATP has not been reported. To verify the latter assumed pathway, experiments with purified and bioenergetically active mitochondria prepared from tubers of Jerusalem artichoke (Helianthus tuberosus L.) were performed. To determine whether NAD biosynthesis might occur, NMN was added to Jerusalem artichoke mitochondria (JAM) and NAD biosynthesis was tested by means of HPLC and spectroscopically. Our results indicate that JAM contain a specific NMNAT inhibited by Na-pyrophosphate, AMP and ADP-ribose. The dependence of NAD synthesis rate on NMN concentration shows saturation kinetics with K (m) and V (max) values of 82 ± 1.05 μM and 4.20 ± 0.20 nmol min(-1) mg(-1) protein, respectively. The enzyme's pH and temperature dependence were also investigated. Fractionation studies revealed that mitochondrial NMNAT activity was present in the soluble matrix fraction. The NAD pool needed constant replenishment that might be modulated by environmental inputs. Thus, the mitochondrion in heterotrophic plant tissues ensures NAD biosynthesis by NMNAT activity and helps to orchestrate NAD metabolic network in implementing the survival strategy of cells.
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Affiliation(s)
- Catello Di Martino
- Department of Animal, Plant and Environmental Sciences, University of Molise, Via F. De Sanctis, 86100 Campobasso, Italy
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20
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Cheshchevik VT, Dremza IK, Lapshina EA, Zabrodskaya SV, Kujawa J, Zavodnik IB. Corrections by melatonin of liver mitochondrial disorders under diabetes and acute intoxication in rats. Cell Biochem Funct 2011; 29:481-8. [PMID: 21744370 DOI: 10.1002/cbf.1775] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Revised: 02/16/2011] [Accepted: 05/17/2011] [Indexed: 12/13/2022]
Abstract
The aim of the present work was to investigate the mechanisms of oxidative damage of the liver mitochondria under diabetes and intoxication in rats as well as to evaluate the possibility of corrections of mitochondrial disorders by pharmacological doses of melatonin. The experimental (30 days) streptozotocin-induced diabetes mellitus caused a significant damage of the respiratory activity in rat liver mitochondria. In the case of succinate as a respiratory substrate, the ADP-stimulated respiration rate V₃ considerably decreased (by 25%, p < 0·05) as well as the acceptor control ratio (ACR) V₃/V₂ markedly diminished (by 25%, p < 0·01). We observed a decrease of the ADP-stimulated respiration rate V₃ by 35% (p < 0·05), with glutamate as substrate. In this case, ACR also decreased (by 20%, p < 0·05). Surprisingly, the phosphorylation coefficient ADP/O did not change under diabetic liver damage. Acute rat carbon tetrachloride-induced intoxication resulted in considerable decrease of the phosphorylation coefficient because of uncoupling of the oxidation and phosphorylation processes in the liver mitochondria. The melatonin administration during diabetes (10 mg·kg⁻¹ body weight, 30 days, daily) showed a considerable protective effect on the liver mitochondrial function, reversing the decreased respiration rate V₃ and the diminished ACR to the control values both for succinate-dependent respiration and for glutamate-dependent respiration. The melatonin administration to intoxicated animals (10 mg·kg⁻¹ body weight, three times) partially increased the rate of succinate-dependent respiration coupled with phosphorylation. The impairment of mitochondrial respiratory plays a key role in the development of liver injury under diabetes and intoxication. Melatonin might be considered as an effector that regulates the mitochondrial function under diabetes.
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Affiliation(s)
- Vitali T Cheshchevik
- Institute for Pharmacology and Biochemistry, National Academy of Sciences of Belarus, Grodno, Belarus
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21
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Laus MN, Soccio M, Trono D, Liberatore MT, Pastore D. Activation of the plant mitochondrial potassium channel by free fatty acids and acyl-CoA esters: a possible defence mechanism in the response to hyperosmotic stress. JOURNAL OF EXPERIMENTAL BOTANY 2011; 62:141-54. [PMID: 20801915 DOI: 10.1093/jxb/erq256] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The effect of free fatty acids (FFAs) and acyl-CoA esters on K(+) uptake was studied in mitochondria isolated from durum wheat (Triticum durum Desf.), a species that has adapted well to the semi-arid Mediterranean area and possessing a highly active mitochondrial ATP-sensitive K(+) channel (PmitoK(ATP)), that may confer resistance to environmental stresses. This was made by swelling experiments in KCl solution under experimental conditions in which PmitoK(ATP) activity was monitored. Linoleate and other FFAs (laurate, palmitate, stearate, palmitoleate, oleate, arachidonate, and the non-physiological 1-undecanesulphonate and 5-phenylvalerate), used at a concentration (10 μM) unable to damage membranes of isolated mitochondria, stimulated K(+) uptake by about 2-4-fold. Acyl-CoAs also promoted K(+) transport to a much larger extent with respect to FFAs (about 5-12-fold). In a different experimental system based on safranin O fluorescence measurements, the dissipation of electrical membrane potential induced by K(+) uptake via PmitoK(ATP) was found to increase in the presence of 5-phenylvalerate and palmitoyl-CoA, both unable to elicit the activity of the Plant Uncoupling Protein. This result suggests a direct activation of PmitoK(ATP). Stimulation of K(+) transport by FFAs/acyl-CoAs resulted in a widespread phenomenon in plant mitochondria from different mono/dicotyledonous species (bread wheat, barley, triticale, maize, lentil, pea, and topinambur) and from different organs (root, tuber, leaf, and shoot). Finally, an increase in mitochondrial FFAs up to a content of 50 nmol mg(-1) protein, which was able to activate PmitoK(ATP) strongly, was observed under hyperosmotic stress conditions. Since PmitoK(ATP) may act against environmental/oxidative stress, its activation by FFAs/acyl-CoAs is proposed to represent a physiological defence mechanism.
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Affiliation(s)
- Maura N Laus
- Dipartimento di Scienze Agro-ambientali, Chimica e Difesa Vegetale, Facoltà di Agraria, Università degli Studi di Foggia, Via Napoli, 25-71122 Foggia, Italy
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22
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Elthon TE, McIntosh L. Identification of the alternative terminal oxidase of higher plant mitochondria. Proc Natl Acad Sci U S A 2010; 84:8399-403. [PMID: 16593898 PMCID: PMC299550 DOI: 10.1073/pnas.84.23.8399] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In addition to cytochrome oxidase, plant mitochondria have a second terminal oxidase called the alternative oxidase. The alternative oxidase is of great interest in that energy is not conserved when electrons flow through it. The potential energy of the system is thus lost as heat, and, in plants with high levels of the alternative oxidase, this results in thermogenesis. We have purified the alternative oxidase from mitochondria of the thermogenic spadix of Sauromatum guttatum and have identified its polypeptide constituents by using polyclonal antibodies. A 166-fold purification was achieved through a combination of cation-exchange (carboxymethyl-Sepharose) and hydrophobic-interaction (phenyl-Sepharose) chromatography. Polyclonal antibodies raised to the CM-Sepharose fractions readily immunoprecipitated alternative oxidase activity and immunoprecipitated four of the proteins that copurify with the activity. These proteins have apparent molecular masses of 37, 36, 35.5, and 35 kDa. Polyclonal antibodies raised individually to the 37-, 36-, and 35.5- plus 35-kDa proteins cross-reacted with all of these proteins, indicating the presence of common antigenic sites. The 37-kDa protein appears to be constitutive in Sauromatum, whereas expression of the 36- and 35-kDa proteins was correlated with presence of alternative pathway activity. The 35.5-kDa protein appears with loss of alternative pathway activity during senescence, indicating that this protein may be a degradation product of the 36-kDa protein. Binding of anti-36-kDa protein antibodies to total mitochondrial protein blots of five plant species indicated that similar proteins were always present when alternative pathway activity was observed.
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Affiliation(s)
- T E Elthon
- Michigan State University-Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI 48824
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23
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Petrussa E, Casolo V, Peresson C, Krajnáková J, Macrì F, Vianello A. Activity of a KATP+ channel in Arum spadix mitochondria during thermogenesis. JOURNAL OF PLANT PHYSIOLOGY 2008; 165:1360-9. [PMID: 18177980 DOI: 10.1016/j.jplph.2007.10.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2007] [Accepted: 10/06/2007] [Indexed: 05/19/2023]
Abstract
This report demonstrates that mitochondria isolated from thermogenic Arum spadices possess an ATP-sensitive potassium channel--responsible for electrical potential (DeltaPsi) collapse and mitochondrial swelling--whose characteristics are similar to those previously described in pea and wheat mitochondria. In order to study the relationship between this K(ATP)(+) channel and the uncoupled respiration, linked to thermogenesis, K(+) transport activities were compared with those of mitochondria that were isolated from pea stems, soybean suspension cell cultures and Arum tubers. The channel from Arum spadices is highly active and its major features are (i) potassium flux is performed primarily in an inward-rectifying manner; (ii) the influx of K(+) is associated with a matrix volume increase in both energized and non-energized mitochondria; and (iii) its activity depends on the redox state of electron transport chain (ETC) and oxygen availability. In particular, this paper shows that the K(ATP)(+) channel is inwardly activated in parallel with the alternative oxidase (AO). The activation is linked to an ETC-oxidized state and to high oxygen consumption. The putative role of this K(ATP)(+) channel is discussed in relation to flowering of thermogenic Arum spadices.
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Affiliation(s)
- Elisa Petrussa
- Department of Biology and Plant Protection, Section of Plant Biology, University of Udine, Udine, Italy
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24
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Laus MN, Soccio M, Trono D, Cattivelli L, Pastore D. Plant inner membrane anion channel (PIMAC) function in plant mitochondria. PLANT & CELL PHYSIOLOGY 2008; 49:1039-55. [PMID: 18511459 DOI: 10.1093/pcp/pcn082] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
To date, the existence of the plant inner membrane anion channel (PIMAC) has been shown only in potato mitochondria, but its physiological role remains unclear. In this study, by means of swelling experiments in K(+) and ammonium salts, we characterize a PIMAC-like anion-conducting pathway in mitochondria from durum wheat (DWM), a monocotyledonous species phylogenetically far from potato. DWM were investigated since they possess a very active potassium channel (PmitoK(ATP)), so implying a very active matching anion uniport pathway and, possibly, a coordinated function. As in potato mitochondria, the electrophoretic uptake of chloride and succinate was inhibited by matrix [H(+)], propranolol, and tributyltin, and was insensitive to Mg(2+), N,N'-dicyclohexylcarbodiimide (DCCD) and mercurials, thus showing PIMAC's existence in DWM. PIMAC actively transports dicarboxylates, oxodicarboxylates, tricarboxylates and Pi. Interestingly, a novel mechanism of swelling in ammonium salts of isolated plant mitochondria is reported, based on electrophoretic anion uptake via PIMAC and ammonium uniport via PmitoK(ATP). PIMAC is inhibited by physiological compounds, such as ATP and free fatty acids, by high electrical membrane potential (Delta Psi), but not by acyl-CoAs or reactive oxygen species. PIMAC was found to cooperate with dicarboxylate carrier by allowing succinate uptake that triggers succinate/malate exchange in isolated DWM. Similar results were obtained using mitochondria from the dicotyledonous species topinambur, so suggesting generalization of results. We propose that PIMAC is normally inactive in vivo due to ATP and Delta Psi inhibition, but activation may occur in mitochondria de-energized by PmitoK(ATP) (or other dissipative systems) to replace or integrate the operation of classical anion carriers.
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Affiliation(s)
- Maura Nicoletta Laus
- Dipartimento di Scienze Agro-ambientali, Chimica e Difesa Vegetale, Facoltà di Agraria, Università degli Studi di Foggia, Via Napoli, 25, 71100 Foggia, Italy
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25
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Onda Y, Kato Y, Abe Y, Ito T, Morohashi M, Ito Y, Ichikawa M, Matsukawa K, Kakizaki Y, Koiwa H, Ito K. Functional coexpression of the mitochondrial alternative oxidase and uncoupling protein underlies thermoregulation in the thermogenic florets of skunk cabbage. PLANT PHYSIOLOGY 2008; 146:636-45. [PMID: 18162588 PMCID: PMC2245847 DOI: 10.1104/pp.107.113563] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Two distinct mitochondrial energy dissipating systems, alternative oxidase (AOX) and uncoupling protein (UCP), have been implicated as crucial components of thermogenesis in plants and animals, respectively. To further clarify the physiological roles of AOX and UCP during homeothermic heat production in the thermogenic skunk cabbage (Symplocarpus renifolius), we identified the thermogenic cells and performed expression and functional analyses of these genes in this organism. Thermographic analysis combined with in situ hybridization revealed that the putative thermogenic cells surround the stamens in the florets of skunk cabbage and coexpress transcripts for SrAOX, encoding Symplocarpus AOX, and SrUCPb, encoding a novel UCP that lacks a fifth transmembrane segment. Mitochondria isolated from the thermogenic florets exhibited substantial linoleic acid (LA)-inducible uncoupling activities. Moreover, our results demonstrate that LA is capable of inhibiting the mitochondrial AOX pathway, whereas the proportion of pyruvate-stimulated AOX capacity was not significantly affected by LA. Intriguingly, the protein expression levels for SrAOX and SrUCPb were unaffected even when the ambient air temperatures increased from 10.3 degrees C to 23.1 degrees C or from 8.3 degrees C to 24.9 degrees C. Thus, our results suggest that functional coexpression of AOX and UCP underlies the molecular basis of heat production, and that posttranslational modifications of these proteins play a crucial role in regulating homeothermic heat production under conditions of natural ambient temperature fluctuations in skunk cabbage.
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Affiliation(s)
- Yoshihiko Onda
- United Graduate School of Agricultural Science, Iwate University, Iwate 020-8550, Japan
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26
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Abstract
We investigated the metabolism of L-lactate in mitochondria isolated from potato tubers grown and saved after harvest in the absence of any chemical agents. Immunologic analysis by western blot using goat polyclonal anti-lactate dehydrogenase showed the existence of a mitochondrial lactate dehydrogenase, the activity of which could be measured photometrically only in mitochondria solubilized with Triton X-100. The addition of L-lactate to potato tuber mitochondria caused: (a) a minor reduction of intramitochondrial pyridine nucleotides, whose measured rate of change increased in the presence of the inhibitor of the alternative oxidase salicyl hydroxamic acid; (b) oxygen consumption not stimulated by ADP, but inhibited by salicyl hydroxamic acid; and (c) activation of the alternative oxidase as polarographically monitored in a manner prevented by oxamate, an L-lactate dehydrogenase inhibitor. Potato tuber mitochondria were shown to swell in isosmotic solutions of ammonium L-lactate in a stereospecific manner, thus showing that L-lactate enters mitochondria by a proton-compensated process. Externally added L-lactate caused the appearance of pyruvate outside mitochondria, thus contributing to the oxidation of extramitochondrial NADH. The rate of pyruvate efflux showed a sigmoidal dependence on L-lactate concentration and was inhibited by phenylsuccinate. Hence, potato tuber mitochondria possess a non-energy-competent L-lactate/pyruvate shuttle. We maintain, therefore, that mitochondrial metabolism of L-lactate plays a previously unsuspected role in the response of potato to hypoxic stress.
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Affiliation(s)
- Gianluca Paventi
- Dipartimento di Scienze per la Salute, Università del Molise, Via De Sanctis, 86100 Campobasso, Italy
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27
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Trono D, Soccio M, Mastrangelo AM, De Simone V, Di Fonzo N, Pastore D. The transcript levels of two plant mitochondrial uncoupling protein (pUCP)-related genes are not affected by hyperosmotic stress in durum wheat seedlings showing an increased level of pUCP activity. Biosci Rep 2007; 26:251-61. [PMID: 16855867 DOI: 10.1007/s10540-006-9020-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Etiolated early seedlings of durum wheat submitted to moderate and severe salt (NaCl) and osmotic (mannitol) stress showed no relevant increase of both transcript levels of two plant uncoupling protein (pUCP)-related genes and maximal pUCP activity in purified mitochondria (which estimates protein level); contrarily, pUCP functioning due to endogenous free fatty acids strongly increased. These results show that pUCP activation under hyperosmotic stress may be due to modulation of pUCP reaction rather than to an increased protein synthesis. Finally, a properly developed method, based on a single membrane potential measurement, to evaluate both pUCP maximal activity and functioning, is reported.
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Affiliation(s)
- Daniela Trono
- Istituto Sperimentale per la Cerealicoltura-CRA, S.S. 16 Km 675, 71100, Foggia, Italy.
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Di Martino C, Pizzuto R, Pallotta ML, De Santis A, Passarella S. Mitochondrial transport in proline catabolism in plants: the existence of two separate translocators in mitochondria isolated from durum wheat seedlings. PLANTA 2006; 223:1123-33. [PMID: 16322984 DOI: 10.1007/s00425-005-0166-z] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2005] [Accepted: 10/31/2005] [Indexed: 05/05/2023]
Abstract
Abiotic stresses, such as high salinity or drought, can cause proline accumulation in plants. Such an accumulation involves proline transport into mitochondria where proline catabolism occurs. By using durum wheat seedlings as a plant model system, we investigated how proline enters isolated coupled mitochondria. The occurrence of two separate translocators for proline, namely a carrier solely for proline and a proline/glutamate antiporter, is shown in a functional study in which we found the following: (1) Mitochondria undergo passive swelling in isotonic proline solutions in a stereospecific manner. (2) Externally added L: -proline (Pro) generates a mitochondrial membrane potential (Delta Psi) with a rate depending on the transport of Pro across the mitochondrial inner membrane. (3) The dependence of the rate of generation of Delta Psi on increasing Pro concentrations exhibits hyperbolic kinetics. Proline transport is inhibited in a competitive manner by the non-penetrant thiol reagent mersalyl, but it is insensitive to the penetrant thiol reagent N-ethylmaleimide (NEM). (4) No accumulation of proline occurs inside the mitochondria as a result of the addition of proline externally, whereas the content of glutamate increases both in mitochondria and in the extramitochondrial phase. (5) Glutamate efflux from mitochondria occurs at a rate which depends on the mitochondrial transport, and it is inhibited in a non-competitive manner by NEM. The dependence of the rate of glutamate efflux on increasing proline concentration shows saturation kinetics. The physiological role of carrier-mediated transport in the regulation of proline catabolism, as well as the possible occurrence of a proline/glutamate shuttle in durum wheat seedlings mitochondria, are discussed.
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Affiliation(s)
- Catello Di Martino
- Dipartimento di Scienze Animali, Vegetali e dell'Ambiente, Università del Molise, Via Francesco De Sanctis, 86100 Campobasso, Italy
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29
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Jezek P, Spacek T, Garlid K, Jabůrek M. Undecanesulfonate does not allosterically activate H+ uniport mediated by uncoupling protein-1 in brown adipose tissue mitochondria. Int J Biochem Cell Biol 2006; 38:1965-74. [PMID: 16807058 DOI: 10.1016/j.biocel.2006.05.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2006] [Revised: 05/23/2006] [Accepted: 05/23/2006] [Indexed: 10/24/2022]
Abstract
Undecanesulfonate is transported by uncoupling protein-1. Its inability to induce H+ uniport with reconstituted uncoupling protein-1 supports fatty acid cycling hypothesis. Rial et al. [Rial, E., Aguirregoitia, E., Jimenez-Jimenez, J., & Ledesma, A. (2004). Alkylsulfonates activate the uncoupling protein UCP1: Implications for the transport mechanism. Biochimica et Biophysica Acta, 1608, 122-130], have challenged the fatty acid cycling by observing uncoupling of brown adipose tissue mitochondria due to undecanesulfonate, interpreted as allosteric activation of uncoupling protein-1. We have estimated undecanesulfonate effects after elimination of endogenous fatty acids by carnitine cycle in the presence or absence of bovine serum albumin. We show that the undecanesulfonate effect is partly due to fatty acid release from albumin when undecanesulfonate releases bound fatty acid and partly represents a non-specific uncoupling protein-independent acceleration of respiration, since it proceeds also in rat heart mitochondria lacking uncoupling protein-1 and membrane potential is not decreased upon addition of undecanesulfonate without albumin. When the net fatty acid-induced uncoupling was assayed, the addition of undecanesulfonate even slightly inhibited the uncoupled respiration. We conclude that undecanesulfonate does not allosterically activate uncoupling protein-1 and that fatty acid cycling cannot be excluded on a basis of its non-specific effects.
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Affiliation(s)
- Petr Jezek
- Department of Membrane Transport Biophysics, No. 75, Institute of Physiology, Academy of Sciences of the Czech Republic, Vídenská 1083, 14220 Prague 4, Czech Republic.
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30
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Paventi G, Pastore D, Bobba A, Pizzuto R, Di Pede S, Passarella S. Plant uncoupling protein in mitochondria from aged-dehydrated slices of Jerusalem artichoke tubers becomes sensitive to superoxide and to hydrogen peroxide without increase in protein level. Biochimie 2005; 88:179-88. [PMID: 16181725 DOI: 10.1016/j.biochi.2005.07.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2005] [Accepted: 07/27/2005] [Indexed: 11/17/2022]
Abstract
We investigated the occurrence of the plant Uncoupling Protein (UCP) in mitochondria isolated from both fresh (f-JAM) and aged-dehydrated (a-d-JAM) slices of Jerusalem artichoke tubers (Helianthus tuberosus L.). The presence of UCP was shown by immunological analysis and its function was investigated by measuring the decrease of the mitochondrial membrane potential due to linoleic acid (LA) and its inhibition by purine nucleotides under conditions in which the adenine nucleotide translocator (ANT) was inhibited by atractyloside (Atr). f-JAM and a-d-JAM had the same protein content, but differed from one another with respect to purine nucleotide inhibition, substrate specificity, and sensitivity to ROS. Hydrogen peroxide and superoxide anion, generated in situ by xanthine plus xanthine oxidase, caused a significant increase in the UCP function in a-d-JAM, but not in f-JAM. This occurred in a manner sensitive to ATP, but not to Atr, thus showing that ANT has no role in the process. The dependence of the rate of membrane potential decrease on increasing LA concentrations, either in the absence or the presence of ROS, showed a sigmoidal saturation both in f-JAM and a-d-JAM. However, addition of ROS in a-d-JAM resulted in about 40% increase of the Vmax value, with no change in the K0.5 (about 20 microM), whereas in f-JAM no effect on either the Vmax or K0.5 (about 28 microM) was found. Furthermore, a decreased ROS production as a result of LA addition was found in both f-JAM and a-d-JAM, the effect being more marked in a-d-JAM.
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Affiliation(s)
- Gianluca Paventi
- Dipartimento di Scienze Animali, Vegetali e dell'Ambiente, Facoltà di Agraria, Università del Molise, Via De Sanctis, 86100 Campobasso, Italy
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31
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Krause F, Reifschneider NH, Vocke D, Seelert H, Rexroth S, Dencher NA. “Respirasome”-like Supercomplexes in Green Leaf Mitochondria of Spinach. J Biol Chem 2004; 279:48369-75. [PMID: 15342644 DOI: 10.1074/jbc.m406085200] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Higher plant mitochondria have many unique features compared with their animal and fungal counterparts. This is to a large extent related to the close functional interdependence of mitochondria and chloroplasts, in which the two ATP-generating processes of oxidative phosphorylation and photosynthesis, respectively, take place. We show that digitonin treatment of mitochondria contaminated with chloroplasts from spinach (Spinacia oleracea) green leaves at two different buffer conditions, performed to solubilize oxidative phosphorylation supercomplexes, selectively extracts the mitochondrial membrane protein complexes and only low amounts of stroma thylakoid membrane proteins. By analysis of digitonin extracts from partially purified mitochondria of green leaves from spinach using blue and colorless native electrophoresis, we demonstrate for the first time that in green plant tissue a substantial proportion of the respiratory complex IV is assembled with complexes I and III into "respirasome"-like supercomplexes, previously observed in mammalian, fungal, and non-green plant mitochondria only. Thus, fundamental features of the supramolecular organization of the standard respiratory complexes I, III, and IV as a respirasome are conserved in all higher eukaryotes. Because the plant respiratory chain is highly branched possessing additional alternative enzymes, the functional implications of the occurrence of respiratory supercomplexes in plant mitochondria are discussed.
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Affiliation(s)
- Frank Krause
- Physical Biochemistry, Department of Chemistry, Darmstadt University of Technology, Petersenstrasse 22, D-64287 Darmstadt, Germany.
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32
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Calegario FF, Cosso RG, Fagian MM, Almeida FV, Jardim WF, Jezek P, Arruda P, Vercesi AE. Stimulation of potato tuber respiration by cold stress is associated with an increased capacity of both plant uncoupling mitochondrial protein (PUMP) and alternative oxidase. J Bioenerg Biomembr 2004; 35:211-20. [PMID: 13678272 DOI: 10.1023/a:1024655514113] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The CO2 evolution of intact potato tubers (Solanum tuberosum, L., var. "Bintje") was analyzed during a 10-day period of their warm (25 +/- 2 degrees C) or cold (5 +/- 1 degrees C) storage, to evaluate cold-stress effects on expression and activities of plant uncoupling mitochondrial protein (PUMP) and alternative oxidase (AOX). CO2 evolution rates were analyzed at 20 degrees C, to reflect their possible capacities. The 20 degrees C CO2 production declined from 13 to 8 mg kg(-1) h(-1) after 2 days of warm storage and then (after 3 to 7 days) decreased from 8 to 6.5 mg kg(-1) h(-1). In contrast, 20 degrees C CO2 evolution did not change after the first day of cold storage, increased up to 14.5 mg kg(-1) h(-1) after 2 days, and decreased to about 12 mg kg(-1) h(-1) after 3 to 7 days of cold storage. Cold storage increased PUMP expression as detected by Western blots and led to elevated capacities of both PUMP (44%) and CN-resistant AOX (10 times), but not the cytochrome pathway. Since we found that cold storage led to about the same mitochondrial respiration of 40 nmol O2 min(-1) mg(-1) attributable to each of the respective proteins, we conclude that both AOX and PUMP equally contribute to adaptation of potato tubers to cold.
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Affiliation(s)
- Fagoni Fayer Calegario
- Departamento de Patologia Clínica, NMCE, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, 13083-970, Campinas, SP, Brazil
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33
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VIROLAINEN EIJA, BLOKHINA OLGA, FAGERSTEDT KURT. Ca(2+)-induced high amplitude swelling and cytochrome c release from wheat (Triticum aestivum L.) mitochondria under anoxic stress. ANNALS OF BOTANY 2002; 90:509-16. [PMID: 12324275 PMCID: PMC4240387 DOI: 10.1093/aob/mcf221] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Under stress conditions, mitochondria sense metabolic changes, e.g. in pH, cytoplasmic Ca(2+), energy status, and reactive oxygen species (ROS), and respond by induction of the permeability transition pore (PTP) and by releasing cytochrome c, thus initiating the programmed cell death (PCD) cascade in animal cells. In plant cells, the presence of all the components of the cascade has not yet been shown. In wheat (Triticum aestivum L.) root mitochondria, the onset of anoxia caused rapid dissipation of the inner membrane potential, initial shrinkage of the mitochondrial matrix and the release of previously accumulated Ca(2+). Ca(2+) uptake by mitochondria was dependent on the presence of inorganic phosphate. Treatment of mitochondria with high micromolar and millimolar Ca(2+) (but not Mg(2+)) concentrations induced high amplitude swelling, indicative of PTP opening. Alterations in mitochondrial volume were confirmed by transmission electron microscopy. Mitochondrial swelling was not sensitive to cyclosporin A (CsA)-an inhibitor of mammalian PTP. The release of cytochrome c was monitored under lack of oxygen. Anoxia alone failed to induce cytochrome c release from mitochondria. Oxygen deprivation and Ca(2+) ions together caused cytochrome c release in a CsA-insensitive manner. This process correlated positively with Ca(2+) concentration and required Ca(2+) localization in the mitochondrial matrix. Functional characteristics of wheat root mitochondria, such as membrane potential, Ca(2+) transport, swelling, and cytochrome c release under lack of oxygen are discussed in relation to PCD.
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Affiliation(s)
- EIJA VIROLAINEN
- Department of Biosciences, Division of Plant Physiology, PO Box 56, FIN‐00014 Helsinki University, Finland
| | - OLGA BLOKHINA
- Department of Biosciences, Division of Plant Physiology, PO Box 56, FIN‐00014 Helsinki University, Finland
| | - KURT FAGERSTEDT
- Department of Biosciences, Division of Plant Physiology, PO Box 56, FIN‐00014 Helsinki University, Finland
- * For correspondence. Fax +358 9 19159552, e‐mail
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34
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Pastore D, Laus MN, Di Fonzo N, Passarella S. Reactive oxygen species inhibit the succinate oxidation-supported generation of membrane potential in wheat mitochondria. FEBS Lett 2002; 516:15-9. [PMID: 11959094 DOI: 10.1016/s0014-5793(02)02454-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In order to gain a first insight into the effects of reactive oxygen species (ROS) on plant mitochondria, we studied the effect of the ROS producing system consisting of xanthine plus xanthine oxidase on the rate of membrane potential (DeltaPsi) generation due to either succinate or NADH addition to durum wheat mitochondria as monitored by safranin fluorescence. We show that the early ROS production inhibits the succinate-dependent, but not the NADH-dependent, DeltaPsi generation and oxygen uptake. This inhibition appears to depend on the impairment of mitochondrial permeability to succinate. It does not involve mitochondrial thiol groups sensitive to either mersalyl or N-ethylmaleimide and might involve both protein residues and/or membrane lipids, as suggested by the mixed nature. We propose that, during oxidative stress, early generation of ROS can affect plant mitochondria by impairing metabolite transport, thus preventing further substrate oxidation, DeltaPsi generation and consequent large-scale ROS production.
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Affiliation(s)
- Donato Pastore
- Dipartimento di Scienze Animali, Vegetali e dell'Ambiente, Facoltà di Agraria, Università del Molise, Via De Sanctis, 86100, Campobasso, Italy
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35
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Affourtit C, Albury MS, Crichton PG, Moore AL. Exploring the molecular nature of alternative oxidase regulation and catalysis. FEBS Lett 2002; 510:121-6. [PMID: 11801238 DOI: 10.1016/s0014-5793(01)03261-6] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Plant mitochondria contain a non-protonmotive alternative oxidase (AOX) that couples the oxidation of ubiquinol to the complete reduction of oxygen to water. In this paper we review theoretical and experimental studies that have contributed to our current structural and mechanistic understanding of the oxidase and to the clarification of the molecular nature of post-translational regulatory phenomena. Furthermore, we suggest a catalytic cycle for AOX that involves at least one transient protein-derived radical. The model is based on the reviewed information and on recent insights into the mechanisms of cytochrome c oxidase and the hydroxylase component of methane monooxygenase.
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Affiliation(s)
- Charles Affourtit
- Department of Biochemistry, University of Sussex, Falmer, Brighton BN1 9QG, UK.
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36
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Affourtit C, Krab K, Leach GR, Whitehouse DG, Moore AL. New insights into the regulation of plant succinate dehydrogenase. On the role of the protonmotive force. J Biol Chem 2001; 276:32567-74. [PMID: 11350973 DOI: 10.1074/jbc.m103111200] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Regulation of succinate dehydrogenase was investigated using tightly coupled potato tuber mitochondria in a novel fashion by simultaneously measuring the oxygen uptake rate and the ubiquinone (Q) reduction level. We found that the activation level of the enzyme is unambiguously reflected by the kinetic dependence of the succinate oxidation rate upon the Q-redox poise. Kinetic results indicated that succinate dehydrogenase is activated by both ATP (K(1/2) approximately 3 microm) and ADP. The carboxyatractyloside insensitivity of these stimulatory effects indicated that they occur at the cytoplasmic side of the mitochondrial inner membrane. Importantly, our novel approach revealed that the enzyme is also activated by oligomycin (K(1/2) approximately 16 nm). Time-resolved kinetic measurements of succinate dehydrogenase activation by succinate furthermore revealed that the activity of the enzyme is negatively affected by potassium. The succinate-induced activation (+/-K(+)) is prevented by the presence of an uncoupler. Together these results demonstrate that in vitro activity of succinate dehydrogenase is modulated by the protonmotive force. We speculate that the widely recognized activation of the enzyme by adenine nucleotides in plants is mediated in this manner. A mechanism that could account for such regulation is suggested and ramifications for its in vivo relevance are discussed.
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Affiliation(s)
- C Affourtit
- Department of Biochemistry, School of Biological Sciences, University of Sussex, Falmer, Brighton BN1 9QG, United Kingdom.
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37
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Petrussa E, Casolo V, Braidot E, Chiandussi E, Macrì F, Vianello A. Cyclosporin A induces the opening of a potassium-selective channel in higher plant mitochondria. J Bioenerg Biomembr 2001; 33:107-17. [PMID: 11456216 DOI: 10.1023/a:1010796314162] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The immunosuppressive drug, cyclosporin A (CsA), induces the generation of a transmembrane electrical potential difference (deltapsi) in deenergized plant mitochondria incubated in sucrose-based media. Build up of deltapsi is prevented by external monovalent cations in the order K+ > Rb+ = Li+ > Na+, or by the protonophore carbonyl cyanide p-trifluoromethoxyphenylhydrazone, which also collapses the deltapsi generated by CsA. Entry of K+ into mitochondria can be monitored as swelling by incubating the organelles in a medium containing KCl to maintain constant osmolarity. This swelling is inhibited by ATP and stimulated by CsA or valinomycin. In addition, in mitochondria energized by succinate, KCl causes a dissipation of deltapsi, with sigmoidal kinetics, which is favored by CsA. Therefore, plant mitochondria appear to possess a K+ selective, voltage-dependent channel, which is opened by CsA, regulated by the redox state, and inhibited by nucleotides. The hypothetical roles of this new K+ATP channel are discussed in relation to its potential involvement in mitochondrial volume regulation, thermogenesis, apoptosis, and/or prevention of reactive oxygen species formation in plants.
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Affiliation(s)
- E Petrussa
- Department of Biology and Agro-industrial Economics, University of Udine, Italy
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38
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Affourtit C, Krab K, Moore AL. Control of plant mitochondrial respiration. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1504:58-69. [PMID: 11239485 DOI: 10.1016/s0005-2728(00)00239-5] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Plant mitochondria are characterised by the presence of both phosphorylating (cytochrome) and non-phosphorylating (alternative) respiratory pathways, the relative activities of which directly affect the efficiency of mitochondrial energy conservation. Different approaches to study the regulation of the partitioning of reducing equivalents between these routes are critically reviewed. Furthermore, an updated view is provided regarding the understanding of plant mitochondrial respiration in terms of metabolic control. We emphasise the extent to which kinetic modelling and 'top-down' metabolic control analysis improve the insight in phenomena related to plant mitochondrial respiration. This is illustrated with an example regarding the affinity of the plant alternative oxidase for oxygen.
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Affiliation(s)
- C Affourtit
- Department of Biochemistry, University of Sussex, Falmer, Brighton, UK.
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39
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Affourtit C, Heaney SP, Moore AL. Mitochondrial electron transfer in the wheat pathogenic fungus Septoria tritici: on the role of alternative respiratory enzymes in fungicide resistance. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1459:291-8. [PMID: 11004442 DOI: 10.1016/s0005-2728(00)00157-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Certain phytopathogenic fungi are able to express alternative NADH- and quinol-oxidising enzymes that are insensitive to inhibitors of the mitochondrial respiratory Complexes I and III. To assess the extent to which such enzymes confer tolerance to respiration-targeted fungicides, an understanding of mitochondrial electron transfer in these species is required. An isolation procedure has been developed which results in intact, active and coupled mitochondria from the wheat pathogen Septoria tritici, as evidenced by morphological and kinetic data. Exogenous NADH, succinate and malate/glutamate are readily oxidised, the latter activity being only partly (approx. 70%) sensitive to rotenone. Of particular importance was the finding that azoxystrobin (a strobilurin fungicide) potently inhibits fungal respiration at the level of Complex III. In some S. tritici strains investigated, a small but significant part of the respiratory activity (approx. 10%) is insensitive to antimycin A and azoxystrobin. Such resistant activity is sensitive to octyl gallate, a specific inhibitor of the plant alternative oxidase. This enzyme, however, could not be detected immunologically. On the basis of the above findings, a conceptual mitochondrial electron transfer chain is presented. Data are discussed in terms of developmental and environmental regulation of the composition of this chain.
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Affiliation(s)
- C Affourtit
- Department of Biochemistry, University of Sussex, Brighton, UK.
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40
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Pastore D, Fratianni A, Di Pede S, Passarella S. Effects of fatty acids, nucleotides and reactive oxygen species on durum wheat mitochondria. FEBS Lett 2000; 470:88-92. [PMID: 10722851 DOI: 10.1016/s0014-5793(00)01292-8] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Linoleic acid (LA) and other fatty acids added to respiring durum wheat mitochondria (DWM) were found to cause a remarkable membrane potential (deltaPsi) decrease, as monitored by measuring safranin fluorescence. The rate of deltaPsi decrease showed (i) saturation dependence on LA concentration; (ii) fatty acid specificity; (iii) inhibition by externally added ATP, GDP, GTP and Mg(2+) and (iv) sigmoid dependence upon initial DeltaPsi, thus suggesting the existence of an active plant mitochondrial uncoupling protein (PUMP) in mitochondria from monocotyledonous species (durum wheat, Triticum durum Desf.). Surprisingly, the rate of the linoleate dependent DeltaPsi decrease was found to be activated by reactive oxygen species (ROS) (hydrogen peroxide and superoxide anion) and, moreover, linoleate proved to lower the mitochondrial generation of superoxide anion. These results suggest that ROS can activate PUMP, thus protecting the cell against mitochondrial ROS production.
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Affiliation(s)
- D Pastore
- Dipartimento di Scienze Animali, Vegetali e dell'Ambiente, Università del Molise, Via De Sanctis, 86100, Campobasso, Italy
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41
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Pastore D, Stoppelli MC, Di Fonzo N, Passarella S. The existence of the K(+) channel in plant mitochondria. J Biol Chem 1999; 274:26683-90. [PMID: 10480870 DOI: 10.1074/jbc.274.38.26683] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In this study, evidence is given that a number of isolated coupled plant mitochondria (from durum wheat, bread wheat, spelt, rye, barley, potato, and spinach) can take up externally added K(+) ions. This was observed by following mitochondrial swelling in isotonic KCl solutions and was confirmed by a novel method in which the membrane potential decrease due to externally added K(+) is measured fluorimetrically by using safranine. A detailed investigation of K(+) uptake by durum wheat mitochondria shows hyperbolic dependence on the ion concentration and specificity. K(+) uptake electrogenicity and the non-competitive inhibition due to either ATP or NADH are also shown. In the whole, the experimental findings reported in this paper demonstrate the existence of the mitochondrial K(+)(ATP) channel in plants (PmitoK(ATP)). Interestingly, Mg(2+) and glyburide, which can inhibit mammalian K(+) channel, have no effect on PmitoK(ATP). In the presence of the superoxide anion producing system (xanthine plus xanthine oxidase), PmitoK(ATP) activation was found. Moreover, an inverse relationship was found between channel activity and mitochondrial superoxide anion formation, as measured via epinephrine photometric assay. These findings strongly suggest that mitochondrial K(+) uptake could be involved in plant defense mechanism against oxidative stress due to reactive oxygen species generation.
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Affiliation(s)
- D Pastore
- Dipartimento di Scienze Animali, Vegetali e dell'Ambiente, Università del Molise, Via De Sanctis, 86100 Campobasso, Italy
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42
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Affourtit C, Albury MS, Krab K, Moore AL. Functional expression of the plant alternative oxidase affects growth of the yeast Schizosaccharomyces pombe. J Biol Chem 1999; 274:6212-8. [PMID: 10037707 DOI: 10.1074/jbc.274.10.6212] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have investigated the extent to which functional expression of the plant alternative oxidase (from Sauromatum guttatum) in Schizosaccharomyces pombe affects yeast growth. When cells are cultured on glycerol, the maximum specific growth rate is decreased from 0.13 to 0.11 h-1 while growth yield is lowered by 20% (from 1. 14 x 10(8) to 9.12 x 10(7) cells ml-1). Kinetic studies suggest that the effect on growth is mitochondrial in origin. In isolated mitochondria we found that the alternative oxidase actively competes with the cytochrome pathway for reducing equivalents and contributes up to 24% to the overall respiratory activity. Metabolic control analysis reveals that the alternative oxidase exerts a considerable degree of control (22%) on total electron flux. Furthermore, the negative control exerted by the alternative oxidase on the flux ratio of electrons through the cytochrome and alternative pathways is comparable with the positive control exerted on this flux-ratio by the cytochrome pathway. To our knowledge, this is the first paper to report a phenotypic effect because of plant alternative oxidase expression. We suggest that the effect on growth is the result of high engagement of the non-protonmotive alternative oxidase in yeast respiration that, consequently, lowers the efficiency of energy conservation and hence growth.
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Affiliation(s)
- C Affourtit
- Department of Biochemistry, School of Biological Sciences, University of Sussex, Falmer, Brighton BN1 9QG, United Kingdom
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43
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Melo AM, Roberts TH, Møller IM. Evidence for the presence of two rotenone-insensitive NAD(P)H dehydrogenases on the inner surface of the inner membrane of potato tuber mitochondria. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1996. [DOI: 10.1016/0005-2728(96)00068-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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44
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The effect of a potential-sensitive barbituric acid molecular probe on the thermal phase transition properties of multilamellar 1,2-dimyristoyl-sn-glycero-3-phosphocholine suspensions. Chem Phys Lipids 1995. [DOI: 10.1016/0009-3084(94)02406-u] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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45
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Ballarin-Denti A, Slayman CL, Kuroda H. Small lipid-soluble cations are not membrane voltage probes for Neurospora or Saccharomyces. BIOCHIMICA ET BIOPHYSICA ACTA 1994; 1190:43-56. [PMID: 8110820 DOI: 10.1016/0005-2736(94)90033-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Small lipid-soluble cations, such as tetraphenylphosphonium (TPP+) and tetraphenylarsonium (TPA+) are frequently used as probes of membrane voltage (delta psi, or Vm) for small animal cells, organelles, and vesicles. Because much controversy has accompanied corresponding measurements on 'walled' eukaryotic cells (plants, fungi), we studied their transport and relation to Vm in the large-celled fungus Neurospora crassa-where Vm can readily be determined with microelectrodes-as well as in the most commonly used model eukaryotic cell, the yeast Saccharomyces cerevisiae. We found no reasonable conditions under which the distribution of TPP+ or TPA+, between the cytoplasm (i) and extracellular solution (o), can serve to estimate Vm, even roughly, in either of these organisms. When applied at probe concentrations (i.e., < or = 100 microM, which did not depolarize the cells nor deplete ATP), TPP+ stabilized at ratios (i/o) below 30 in both organisms. That would imply apparent Vm values positive to -90 mV, in the face of directly measured Vm values (in Neurospora) negative to -180 mV. When applied at moderate or high concentrations (1-30 mM), TPP+ and TPA+ induced several phases of depolarization and changes of membrane resistance (Rm), as well as depletion of cytoplasmic energy stores. Only the first phase depolarization, occurring within the perfusion-turnover time and accompanied by a nearly proportionate decline of Rm, could have resulted from TPP+ or TPA+ currents per se. And the implied currents were small. Repeated testing, furthermore, greatly reduced the depolarizing effects of these lipid-soluble ions, implicating an active cellular response to decrease membrane permeability.
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Affiliation(s)
- A Ballarin-Denti
- Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, CT 06510
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Rhoads DM, McIntosh L. Cytochrome and Alternative Pathway Respiration in Tobacco (Effects of Salicylic Acid). PLANT PHYSIOLOGY 1993; 103:877-883. [PMID: 12231986 PMCID: PMC159059 DOI: 10.1104/pp.103.3.877] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
In suspension cultures of NT1 tobacco (Nicotiana tabacum L. cv Bright Yellow) cells the cytochrome pathway capacity increased between d 3 and d 4 following subculturing and reached the highest level observed on d 7. The capacity decreased significantly by d 10 and was at the same level on d 14. Both alternative pathway capacity and the amount of the 35-kD alternative oxidase protein increased significantly between d 5 and d 6, reached the highest point observed on d 7, remained constant until d 10, and decreased by d 14. The highest capacities of the alternative and cytochrome pathways and the highest amount of the 35-kD protein were attained on the day that cell cultures reached a stationary phase of growth. Addition of salicylic acid to cell cultures on d 4 caused a significant increase in alternative pathway capacity and a dramatic accumulation of the 35-kD protein by 12 h. The alternative pathway capacity and the protein level reached the highest level observed by 16 h after salicylic acid addition, and the cytochrome pathway capacity was at about the same level at each time point. The accumulation of the 35-kD alternative oxidase protein was significantly decreased by addition of actinomycin D 1 h before salicylic acid and was blocked by addition of cycloheximide. These results indicate that de novo transcription and translation were necessary for salicylic acid to cause the maximum accumulation of the 35-kD protein.
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Affiliation(s)
- D. M. Rhoads
- Michigan State University-Department of Energy Plant Research Laboratory and Biochemistry Department, Michigan State University, East Lansing, Michigan 48824
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Zottini M, Mandolino G, Zannoni D. Oxidation of External NAD(P)H by Mitochondria from Taproots and Tissue Cultures of Sugar Beet (Beta vulgaris). PLANT PHYSIOLOGY 1993; 102:579-585. [PMID: 12231847 PMCID: PMC158815 DOI: 10.1104/pp.102.2.579] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The present study compares the exogenous NAD(P)H oxidation and the membrane potential ([delta][psi]) generated in mitochondria isolated from different tissues of an important agricultural crop, sugar beet (Beta vulgaris}. We observed that mitochondria from taproots, cold-stored taproots, and in vitro-grown tissue cultures contain a functional NADH dehydrogenase, whereas only those isolated from tissue cultures displayed a functional NAD(P)H dehydrogenase. It is interesting that the NADH-dependent [delta][psi] of mitochondria from cold-stored taproots and from tissue cultures was not affected by free Ca2+ ions, whereas free Ca2+ was required for the mitochondrial NADPH oxidation by in vitro-grown cells and cytosolic NADH oxidation by mitochondria from fresh taproots. A tentative model accounting for the different response to Ca2+ ions of the NADH dehydrogenase in mitochondria from cold-stored taproots and tissue cultures of B. vulgaris is discussed.
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Affiliation(s)
- M. Zottini
- Department of Biology, University of Bologna, Via Irnerio 42, 40126 Bologna, Italy (M.Z., D.Z.)
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Rhoads DM, McIntosh L. The salicylic acid-inducible alternative oxidase gene aox1 and genes encoding pathogenesis-related proteins share regions of sequence similarity in their promoters. PLANT MOLECULAR BIOLOGY 1993; 21:615-24. [PMID: 8448361 DOI: 10.1007/bf00014545] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
We have isolated and characterized a genomic clone, lambda AOSG11, corresponding to aox1, which encodes the 42 kDa alternative oxidase precursor protein of Sauromatum guttatum Schott. The sequence of lambda AOSG11 revealed that aox1 consists of four exons separated by three short introns. Exon three contains the region of aox1 that (1) is highly conserved in the corresponding genes of potato, rice, and yeast, and (2) encodes a region of the deduced protein that is predicted to form two transmembrane alpha-helices. Southern blot analysis of restriction endonuclease-digested genomic DNA, indicated that aox1 is a single, nuclear-encoded gene in S. guttatum. We have determined the transcriptional start site of aox1 using nuclease protection and primer extension experiments. Comparison of the putative promoter region of aox1 to promoters of PR1a and GRP8 revealed some sequence similarity.
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Affiliation(s)
- D M Rhoads
- Department of Energy, Michigan State University, East Lansing 48824
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Nolan DP, Voorheis HP. The mitochondrion in bloodstream forms of Trypanosoma brucei is energized by the electrogenic pumping of protons catalysed by the F1F0-ATPase. EUROPEAN JOURNAL OF BIOCHEMISTRY 1992; 209:207-16. [PMID: 1327770 DOI: 10.1111/j.1432-1033.1992.tb17278.x] [Citation(s) in RCA: 100] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Bloodstream forms of Trypanosoma brucei were found to maintain a significant membrane potential across their mitochondrial inner membrane (delta psi m) in addition to a plasma membrane potential (delta psi p). Significantly, the delta psi m was selectively abolished by low concentrations of specific inhibitors of the F1F0-ATPase, such as oligomycin, whereas inhibition of mitochondrial respiration with salicylhydroxamic acid was without effect. Thus, the mitochondrial membrane potential is generated and maintained exclusively by the electrogenic translocation of H+, catalysed by the mitochondrial F1F0-ATPase at the expense of ATP rather than by the mitochondrial electron-transport chain present in T. brucei. Consequently, bloodstream forms of T. brucei cannot engage in oxidative phosphorylation. The mitochondrial membrane potential generated by the mitochondrial F1F0-ATPase in intact trypanosomes was calculated after solving the two-compartment problem for the uptake of the lipophilic cation, methyltriphenylphosphonium (MePh3P+) and was shown to have a value of approximately 150 mV. When the value for the delta psi m is combined with that for the mitochondrial pH gradient (Nolan and Voorheis, 1990), the mitochondrial proton-motive force was calculated to be greater than 190 mV. It seems likely that this mitochondrial proton-motive force serves a role in the directional transport of ions and metabolites across the promitochondrial inner membrane during the bloodstream stage of the life cycle, as well as promoting the import of nuclear-encoded protein into the promitochondrion during the transformation of bloodstream forms into the next stage of the life cycle of T. brucei.
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Affiliation(s)
- D P Nolan
- Department of Biochemistry, Trinity College, Dublin, Ireland
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Rhoads DM, McIntosh L. Salicylic Acid Regulation of Respiration in Higher Plants: Alternative Oxidase Expression. THE PLANT CELL 1992; 4:1131-1139. [PMID: 12297672 PMCID: PMC160203 DOI: 10.1105/tpc.4.9.1131] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Alternative respiratory pathway capacity increases during the development of the thermogenic appendix of a voodoo lily inflorescence. The levels of the alternative oxidase proteins increased dramatically between D-4 (4 days prior to the day of anthesis) and D-3 and continued to increase until the day of anthesis (D-day). The level of salicylic acid (SA) in the appendix is very low early on D-1, but increases to a high level in the evening of D-1. Thermogenesis occurs after a few hours of light on D-day. Therefore, the initial accumulation of the alternative oxidase proteins precedes the increase in SA by 3 days, indicating that other regulators may be involved. A 1.6-kb transcript encoding the alternative oxidase precursor protein accumulated to a high level in the appendix tissue by D-1. Application of SA to immature appendix tissue caused an increase in alternative pathway capacity and a dramatic accumulation of the alternative oxidase proteins and the 1.6-kb transcript. Time course experiments showed that the increase in capacity, protein levels, and transcript level corresponded precisely. The response to SA was blocked by cycloheximide or actinomycin D, indicating that de novo transcription and translation are required. However, nuclear, in vitro transcription assays indicated that the accumulation of the 1.6-kb transcript did not result from a simple increase in the rate of transcription of aox1.
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Affiliation(s)
- D. M. Rhoads
- Department of Energy Plant Research Laboratory and Department of Biochemistry, Michigan State University, East Lansing, Michigan 48824
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