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Gutiérrez-Aguilar M. Mitochondrial calcium transport and permeability transition as rational targets for plant protection. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1861:148288. [PMID: 32800781 DOI: 10.1016/j.bbabio.2020.148288] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 07/23/2020] [Accepted: 08/03/2020] [Indexed: 12/28/2022]
Abstract
The mitochondrial permeability transition (MPT) is a death-inducing mechanism that collapses electrochemical gradients across inner mitochondrial membranes. Several studies in model plants have detailed potential MPT-dependent cell death upon abiotic stress in response to heat shock, ultraviolet radiation, heavy metal toxicity and waterlogging. However, the molecular specifics of the MPT and its possible role on plant cell death remain controversial. This review addresses previous and recent developments on the role(s) of the MPT in plants. Considering these advances, MPT targeting can constitute a plausible strategy to ameliorate cell death in plants upon abiotic stress.
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Affiliation(s)
- Manuel Gutiérrez-Aguilar
- Departamento de Bioquímica, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510 México City, Mexico.
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Structural and functional properties of plant mitochondrial F-ATP synthase. Mitochondrion 2020; 53:178-193. [DOI: 10.1016/j.mito.2020.06.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 05/25/2020] [Accepted: 06/08/2020] [Indexed: 12/13/2022]
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3
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De Col V, Petrussa E, Casolo V, Braidot E, Lippe G, Filippi A, Peresson C, Patui S, Bertolini A, Giorgio V, Checchetto V, Vianello A, Bernardi P, Zancani M. Properties of the Permeability Transition of Pea Stem Mitochondria. Front Physiol 2018; 9:1626. [PMID: 30524297 PMCID: PMC6262314 DOI: 10.3389/fphys.2018.01626] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 10/29/2018] [Indexed: 12/17/2022] Open
Abstract
In striking analogy with Saccharomyces cerevisiae, etiolated pea stem mitochondria did not show appreciable Ca2+ uptake. Only treatment with the ionophore ETH129 (which allows electrophoretic Ca2+ equilibration) caused Ca2+ uptake followed by increased inner membrane permeability, membrane depolarization and Ca2+ release. Like the permeability transition (PT) of mammals, yeast and Drosophila, the PT of pea stem mitochondria was stimulated by diamide and phenylarsine oxide and inhibited by Mg-ADP and Mg-ATP, suggesting a common underlying mechanism; yet, the plant PT also displayed distinctive features: (i) as in mammals it was desensitized by cyclosporin A, which does not affect the PT of yeast and Drosophila; (ii) similarly to S. cerevisiae and Drosophila it was inhibited by Pi, which stimulates the PT of mammals; (iii) like in mammals and Drosophila it was sensitized by benzodiazepine 423, which is ineffective in S. cerevisiae; (iv) like what observed in Drosophila it did not mediate swelling and cytochrome c release, which is instead seen in mammals and S. cerevisiae. We find that cyclophilin D, the mitochondrial receptor for cyclosporin A, is present in pea stem mitochondria. These results indicate that the plant PT has unique features and suggest that, as in Drosophila, it may provide pea stem mitochondria with a Ca2+ release channel.
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Affiliation(s)
- Valentina De Col
- Department of Agricultural, Food, Environmental and Animal Sciences (Di4A), University of Udine, Udine, Italy
| | - Elisa Petrussa
- Department of Agricultural, Food, Environmental and Animal Sciences (Di4A), University of Udine, Udine, Italy
| | - Valentino Casolo
- Department of Agricultural, Food, Environmental and Animal Sciences (Di4A), University of Udine, Udine, Italy
| | - Enrico Braidot
- Department of Agricultural, Food, Environmental and Animal Sciences (Di4A), University of Udine, Udine, Italy
| | - Giovanna Lippe
- Department of Agricultural, Food, Environmental and Animal Sciences (Di4A), University of Udine, Udine, Italy
| | - Antonio Filippi
- Department of Agricultural, Food, Environmental and Animal Sciences (Di4A), University of Udine, Udine, Italy
| | - Carlo Peresson
- Department of Agricultural, Food, Environmental and Animal Sciences (Di4A), University of Udine, Udine, Italy
| | - Sonia Patui
- Department of Agricultural, Food, Environmental and Animal Sciences (Di4A), University of Udine, Udine, Italy
| | - Alberto Bertolini
- Department of Agricultural, Food, Environmental and Animal Sciences (Di4A), University of Udine, Udine, Italy
| | - Valentina Giorgio
- Department of Biomedical Sciences, University of Padova and CNR Neuroscience Institute, Padova, Italy
| | | | - Angelo Vianello
- Department of Agricultural, Food, Environmental and Animal Sciences (Di4A), University of Udine, Udine, Italy
| | - Paolo Bernardi
- Department of Biomedical Sciences, University of Padova and CNR Neuroscience Institute, Padova, Italy
| | - Marco Zancani
- Department of Agricultural, Food, Environmental and Animal Sciences (Di4A), University of Udine, Udine, Italy
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Zancani M, Casolo V, Petrussa E, Peresson C, Patui S, Bertolini A, De Col V, Braidot E, Boscutti F, Vianello A. The Permeability Transition in Plant Mitochondria: The Missing Link. FRONTIERS IN PLANT SCIENCE 2015; 6:1120. [PMID: 26697057 PMCID: PMC4678196 DOI: 10.3389/fpls.2015.01120] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 11/26/2015] [Indexed: 05/17/2023]
Abstract
The synthesis of ATP in mitochondria is dependent on a low permeability of the inner membrane. Nevertheless, mitochondria can undergo an increased permeability to solutes, named permeability transition (PT) that is mediated by a permeability transition pore (PTP). PTP opening requires matrix Ca(2+) and leads to mitochondrial swelling and release of intramembrane space proteins (e.g., cytochrome c). This feature has been initially observed in mammalian mitochondria and tentatively attributed to some components present either in the outer or inner membrane. Recent works on mammalian mitochondria point to mitochondrial ATP synthase dimers as physical basis for PT, a finding that has been substantiated in yeast and Drosophila mitochondria. In plant mitochondria, swelling and release of proteins have been linked to programmed cell death, but in isolated mitochondria PT has been observed in only a few cases and in plant cell cultures only indirect evidence is available. The possibility that mitochondrial ATP synthase dimers could function as PTP also in plants is discussed here on the basis of the current evidence. Finally, a hypothetical explanation for the origin of PTP is provided in the framework of molecular exaptation.
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The mitochondrial permeability transition pore (PTP) — An example of multiple molecular exaptation? BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1817:2072-86. [DOI: 10.1016/j.bbabio.2012.06.620] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Revised: 06/19/2012] [Accepted: 06/21/2012] [Indexed: 11/21/2022]
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6
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Mitochondrial Unselective Channels throughout the eukaryotic domain. Mitochondrion 2011; 11:382-90. [DOI: 10.1016/j.mito.2011.02.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Revised: 02/16/2011] [Accepted: 02/25/2011] [Indexed: 02/03/2023]
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7
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Konràd C, Kiss G, Töröcsik B, Lábár JL, Gerencser AA, Mándi M, Adam-Vizi V, Chinopoulos C. A distinct sequence in the adenine nucleotide translocase from Artemia franciscana embryos is associated with insensitivity to bongkrekate and atypical effects of adenine nucleotides on Ca2+ uptake and sequestration. FEBS J 2011; 278:822-36. [PMID: 21205213 DOI: 10.1111/j.1742-4658.2010.08001.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Mitochondria isolated from embryos of the crustacean Artemia franciscana lack the Ca(2+)-induced permeability transition pore. Although the composition of the pore described in mammalian mitochondria is unknown, the impacts of several effectors of the adenine nucleotide translocase (ANT) on pore opening are firmly established. Notably, ADP, ATP and bongkrekate delay, whereas carboxyatractyloside hastens, Ca(2+)-induced pore opening. Here, we report that adenine nucleotides decreased, whereas carboxyatractyloside increased, Ca(2+) uptake capacity in mitochondria isolated from Artemia embryos. Bongkrekate had no effect on either Ca(2+) uptake or ADP-ATP exchange rate. Transmission electron microscopy imaging of Ca(2+)-loaded Artemia mitochondria showed needle-like formations of electron-dense material in the absence of adenine nucleotides, and dot-like formations in the presence of adenine nucleotides or Mg(2+). Energy-filtered transmission electron microscopy showed the material to be rich in calcium and phosphorus. Sequencing of the Artemia mRNA coding for ANT revealed that it transcribes a protein with a stretch of amino acids in the 198-225 region with 48-56% similarity to those from other species, including the deletion of three amino acids in positions 211, 212 and 219. Mitochondria isolated from the liver of Xenopus laevis, in which the ANT shows similarity to that in Artemia except for the 198-225 amino acid region, demonstrated a Ca(2+)-induced bongkrekate-sensitive permeability transition pore, allowing the suggestion that this region of ANT may contain the binding site for bongkrekate.
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Affiliation(s)
- Csaba Konràd
- Department of Medical Biochemistry, Semmelweis University, Budapest, Hungary
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Azzolin L, von Stockum S, Basso E, Petronilli V, Forte MA, Bernardi P. The mitochondrial permeability transition from yeast to mammals. FEBS Lett 2010; 584:2504-9. [PMID: 20398660 PMCID: PMC2878904 DOI: 10.1016/j.febslet.2010.04.023] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2010] [Revised: 04/01/2010] [Accepted: 04/09/2010] [Indexed: 01/05/2023]
Abstract
Regulated permeability changes have been detected in mitochondria across species. We review here their key features, with the goal of assessing whether a "permeability transition" similar to that observed in higher eukaryotes is present in other species. The recent discoveries (i) that treatment with cyclosporin A (CsA) unmasks an inhibitory site for inorganic phosphate (Pi) [Basso, E., Petronilli, V., Forte, M.A. and Bernardi, P. (2008) Phosphate is essential for inhibition of the mitochondrial permeability transition pore by cyclosporin A and by cyclophilin D ablation. J. Biol. Chem. 283, 26307-26311], the classical inhibitor of the permeability transition of yeast and (ii) that under proper experimental conditions a matrix Ca(2+)-dependence can be demonstrated in yeast as well [Yamada, A., Yamamoto, T., Yoshimura, Y., Gouda, S., Kawashima, S., Yamazaki, N., Yamashita, K., Kataoka, M., Nagata, T., Terada, H., Pfeiffer, D.R. and Shinohara Y. (2009) Ca(2+)-induced permeability transition can be observed even in yeast mitochondria under optimized experimental conditions. Biochim. Biophys. Acta 1787, 1486-1491] suggest that the mitochondrial permeability transition has been conserved during evolution.
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Affiliation(s)
| | | | | | | | - Michael A. Forte
- Vollum Institute, Oregon Health and Sciences University, Portland, Oregon
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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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Contran N, Cerana R, Crosti P, Malerba M. Cyclosporin A inhibits programmed cell death and cytochrome c release induced by fusicoccin in sycamore cells. PROTOPLASMA 2007; 231:193-9. [PMID: 17603747 DOI: 10.1007/s00709-007-0250-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2006] [Accepted: 10/28/2006] [Indexed: 05/05/2023]
Abstract
Programmed cell death plays a vital role in normal plant development, response to environmental stresses, and defense against pathogen attack. Different types of programmed cell death occur in plants and the involvement of mitochondria is still under investigation. In sycamore (Acer pseudoplatanus L.) cultured cells, the phytotoxin fusicoccin induces cell death that shows apoptotic features, including chromatin condensation, DNA fragmentation, and release of cytochrome c from mitochondria. In this work, we show that cyclosporin A, an inhibitor of the permeability transition pore of animal mitochondria, inhibits the cell death, DNA fragmentation, and cytochrome c release induced by fusicoccin. In addition, we show that fusicoccin induces a change in the shape of mitochondria which is not prevented by cyclosporin A. These results suggest that the release of cytochrome c induced by fusicoccin occurs through a cyclosporin A-sensitive system that is similar to the permeability transition pore of animal mitochondria and they make it tempting to speculate that this release may be involved in the phytotoxin-induced programmed cell death of sycamore cells.
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Affiliation(s)
- N Contran
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, Milan
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Petrussa E, Casolo V, Peresson C, Braidot E, Vianello A, Macrì F. The K(ATP)+ channel is involved in a low-amplitude permeability transition in plant mitochondria. Mitochondrion 2005; 3:297-307. [PMID: 16120362 DOI: 10.1016/j.mito.2004.01.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2003] [Revised: 01/27/2004] [Accepted: 01/29/2004] [Indexed: 01/26/2023]
Abstract
Pea (Pisum sativum) stem mitochondria, energized by NADH, succinate or malate plus glutamate, underwent a spontaneous low-amplitude permeability transition (PT), which could be monitored by dissipation of the electrical potential (deltapsi) or swelling. The occurrence of the latter effects was dependent on O2 availability, because O2 shortage anticipated the manifestation of both deltapsi dissipation and swelling. Spontaneous deltapsi collapse was also monitored in sucrose-resuspended mitochondria and again O2 deprivation caused an anticipation of the phenomenon. However, in this case deltapsi dissipation was not accompanied by a parallel mitochondrial swelling. The latter effect was, indeed, evident only if mitochondria were resuspended in KCl (as osmoticum), or other cations with a molecular mass up to 100 Da (choline+). PT was also induced by protonophores (carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP) or free fatty acids) or valinomycin (only in KCl). The FCCP-induced dissipation of deltapsi and swelling were inhibited by ATP and stimulated (anticipated) by cyclosporin A or O2 shortage. The FCCP-induced PT was accompanied by the release of pyridine nucleotides from the matrix and of cytochrome c from the intermembrane space of KCl-resuspended mitochondria. The spontaneous and FCCP-induced low-amplitude PT of plant mitochondria are interpreted as due to the activity of a recently identified K(ATP)+ channel whose open/closed state is dependent on polarization of the inner membrane and on the oxidoreductive state of some sulfhydryl groups.
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Affiliation(s)
- Elisa Petrussa
- Department of Biology and Agro-Industrial Economics, Section of Plant Biology, University of Udine, via Cotonificio 108, Udine I-33100, Italy
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Arpagaus S, Rawyler A, Braendle R. Occurrence and characteristics of the mitochondrial permeability transition in plants. J Biol Chem 2002; 277:1780-7. [PMID: 11704674 DOI: 10.1074/jbc.m109416200] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The behavior of purified potato mitochondria toward the main effectors of the animal mitochondrial permeability transition has been studied by light scattering, fluorescence, SDS-polyacrylamide gel electrophoresis, and immunoblotting techniques. The addition of Ca(2+) induces a phosphate-dependent swelling that is fully inhibited by cyclosporin A if dithioerythritol is present. Mg(2+) cannot be substituted for Ca(2+) but competes with it. Disruption of the outer membrane and release of several proteins, including cytochrome c, occur upon completion of swelling. Ca(2+)-induced swelling is delayed and its rate is decreased when pH is shifted from 7.4 to 6.6. It is accelerated by diamide, phenylarsine oxide, and linolenic acid. In the absence of Ca(2+), however, linolenic acid (< or =20 microm) rapidly dissipates the succinate-driven membrane potential while having no effect on mitochondrial volume. Anoxic conditions favor in vitro swelling and the concomitant release of cytochrome c and of other proteins in a pH-dependent way. These data indicate that the classical mitochondrial permeability transition occurs also in plants. This may have important implications for our understanding of cell stress and death processes.
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Affiliation(s)
- Silvio Arpagaus
- Institute of Plant Sciences, University of Bern, Altenbergrain 23, Bern CH-3013, Switzerland.
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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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Toninello A, Salvi M, Colombo L. The membrane permeability transition in liver mitochondria of the great green goby Zosterisessor ophiocephalus (Pallas). J Exp Biol 2000; 203:3425-34. [PMID: 11044381 DOI: 10.1242/jeb.203.22.3425] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Liver mitochondria from the great green goby Zosterisessor ophiocephalus (Pallas) normally exhibit bioenergetic variables (membrane potential 165+/−7 mV; respiratory control ratio 6.6+/−0.4; ADP/O ratio 1.85+/−0.8; means +/− s.e.m., N=6) and activities of physiological transport systems (phosphate/proton symporter, adenine nucleotide antiporter, Ca(2+) electrophoretic uniporter) comparable with those of rat liver mitochondria. When incubated in the presence of Ca(2+) and an inducer agent such as phosphate, these mitochondria undergo a complete collapse of membrane potential accompanied by a large-amplitude swelling of the matrix, influx of sucrose from the incubation medium, release of endogenous Mg(2+) and K(+) (approximately 90% of the total) and of preaccumulated Ca(2+) and oxidation of endogenous pyridine nucleotides. All these phenomena, which are completely eliminated by cyclosporin A and inhibited with different efficacies by Mg(2+) and spermine, demonstrate that the induction of the permeability transition in this type of mitochondria has characteristics similar to those described in rat liver mitochondria. In contrast, the requirement for very high Ca(2+) concentrations (greater than 100 micromol l(−1) for the induction of the permeability transition represents a very important difference that distinguishes this phenomenon in fish and mammalian mitochondria.
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Affiliation(s)
- A Toninello
- Dipartimento di Chimica Biologica dell'Università di Padova, Centro delle Biomembrane del C.N.R., Italy.
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Bakeeva LE, Kirnos MD, Aleksandrushkina NI, Kazimirchyuk SB, Zamyatnina VA, Yaguzhinsky LS, Vanyushin BF. Subcellular reorganization of mitochondria producing heavy DNA in aging wheat coleoptiles. FEBS Lett 1999; 457:122-5. [PMID: 10486577 DOI: 10.1016/s0014-5793(99)01025-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Unusual closed membrane vesicles containing one or more mitochondria were isolated from homogenates of aging wheat coleoptiles. Very similar (or the same) bodies were shown to exist in situ in vacuoles of undividing cells in the apical part of intact senescent coleoptiles. Vesicles isolated from coleoptile homogenate free of nuclei by 10 min centrifugation at 1700 x g and traditional mitochondria (sedimented at between 4300 x g and 17,400 x g) are similar in respiration rate, composition and content of cytochromes and sensitivity to respiration inhibitors. However, vesicles contain about 2-fold more Ca2+ ions than free mitochondria do. The specific feature of vesicles containing mitochondria in aging coleoptiles is an intensive synthesis of heavy (rho = 1.718 g/cm3) mitochondrial DNA (H-mtDNA). Thus, aging in plants is accompanied by an increased selective H-mtDNA production and change in subcellular organization of mitochondria.
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Affiliation(s)
- L E Bakeeva
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Russia
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