1
|
Mazorra Morales LM, Cosme Silva GM, Santana DB, Pireda SF, Dorighetto Cogo AJ, Heringer ÂS, de Oliveira TDR, Reis RS, Dos Santos Prado LA, de Oliveira AV, Silveira V, Da Cunha M, Barros CF, Façanha AR, Baldet P, Bartoli CG, da Silva MG, Oliveira JG. Mitochondrial dysfunction associated with ascorbate synthesis in plants. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2022; 185:55-68. [PMID: 35661586 DOI: 10.1016/j.plaphy.2022.05.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 05/06/2022] [Accepted: 05/19/2022] [Indexed: 06/15/2023]
Abstract
Mitochondria are the major organelles of energy production; however, active mitochondria can decline their energetic role and show a dysfunctional status. Mitochondrial dysfunction was induced by high non-physiological level of L-galactone-1,4-lactone (L-GalL), the precursor of ascorbate (AsA), in plant mitochondria. The dysfunction induced by L-GalL was associated with the fault in the mitochondrial electron partition and reactive oxygen species (ROS) over-production. Using mitochondria from RNAi-plant lines harbouring silenced L-galactone-1,4-lactone dehydrogenase (L-GalLDH) activity, it was demonstrated that such dysfunction is dependent on this enzyme activity. The capacity of alternative respiration was strongly decreased by L-GalL, probably mediated by redox-inactivation of the alternative oxidase (AOX) enzyme. Although, alternative respiration was shown to be the key factor that helps support AsA synthesis in dysfunctional mitochondria. Experiments with respiratory inhibitors showed that ROS formation and mitochondrial dysfunction were more associated with the decline in the activities of COX (cytochrome oxidase) and particularly AOX than with the lower activities of respiratory complexes I and III. The application of high L-GalL concentrations induced proteomic changes that indicated alterations in proteins related to oxidative stress and energetic status. However, supra-optimal L-GalL concentration was not deleterious for plants. Instead, the L-GalLDH activity could be positive. Indeed, it was found that wild type plants performed better growth than L-GalLDH-RNAi plants in response to high non-physiological L-GalL concentrations.
Collapse
Affiliation(s)
- Luis Miguel Mazorra Morales
- Laboratório de Melhoramento Genético Vegetal, Centro de Ciências e Tecnologias Agropecuárias, Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Campos dos Goytacazes, Rio de Janeiro, CEP 28013-602, Brazil; Laboratório de Ciências Físicas, Centro de Ciência Tecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Campos dos Goytacazes, Rio de Janeiro, CEP 28013-602, Brazil
| | - Gláucia Michelle Cosme Silva
- Laboratório de Melhoramento Genético Vegetal, Centro de Ciências e Tecnologias Agropecuárias, Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Campos dos Goytacazes, Rio de Janeiro, CEP 28013-602, Brazil
| | - Diederson Bortolini Santana
- Laboratório de Melhoramento Genético Vegetal, Centro de Ciências e Tecnologias Agropecuárias, Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Campos dos Goytacazes, Rio de Janeiro, CEP 28013-602, Brazil
| | - Saulo F Pireda
- Laboratório de Biologia Celular e Tecidual, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Campos dos Goytacazes, Rio de Janeiro, CEP 28013-602, Brazil
| | - Antônio Jesus Dorighetto Cogo
- Laboratório de Biologia Celular e Tecidual, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Campos dos Goytacazes, Rio de Janeiro, CEP 28013-602, Brazil
| | - Ângelo Schuabb Heringer
- Laboratório de Biotecnologia, Universidade Estadual do Norte Fluminense "Darcy Ribeiro" (UENF), Campos dos Goytacazes, RJ, Brazil
| | - Tadeu Dos Reis de Oliveira
- Laboratório de Biologia Celular e Tecidual, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Campos dos Goytacazes, Rio de Janeiro, CEP 28013-602, Brazil
| | - Ricardo S Reis
- Laboratório de Biotecnologia, Universidade Estadual do Norte Fluminense "Darcy Ribeiro" (UENF), Campos dos Goytacazes, RJ, Brazil
| | - Luís Alfredo Dos Santos Prado
- Laboratório de Biologia Celular e Tecidual, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Campos dos Goytacazes, Rio de Janeiro, CEP 28013-602, Brazil
| | - André Vicente de Oliveira
- Laboratório de Melhoramento Genético Vegetal, Centro de Ciências e Tecnologias Agropecuárias, Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Campos dos Goytacazes, Rio de Janeiro, CEP 28013-602, Brazil
| | - Vanildo Silveira
- Laboratório de Biotecnologia, Universidade Estadual do Norte Fluminense "Darcy Ribeiro" (UENF), Campos dos Goytacazes, RJ, Brazil
| | - Maura Da Cunha
- Laboratório de Biologia Celular e Tecidual, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Campos dos Goytacazes, Rio de Janeiro, CEP 28013-602, Brazil
| | - Cláudia F Barros
- Laboratório de Botânica Estrutural, Instituto de Pesquisas Jardim Botânico do Rio de Janeiro - IPJBRJ, Brazil
| | - Arnoldo R Façanha
- Laboratório de Biologia Celular e Tecidual, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Campos dos Goytacazes, Rio de Janeiro, CEP 28013-602, Brazil
| | - Pierre Baldet
- Institut National de la Recherche Agronomique, Université Bordeaux 1, Université Victor Ségalen-Bordeaux 2, Institut Fédératif de Recherche 103, Unité Mixte de Recherche 619 sur la Biologie du Fruit, Centre de Recherche Institut National de la Recherche Agronomique de Bordeaux, BP 81, 33883, Villenave d'Ornon cedex, France
| | - Carlos G Bartoli
- Instituto de Fisiología Vegetal, Facultad Ciencias Agrarias y Forestales, Universidad Nacional de La Plata, CCT-CONICET, cc327 1900, La Plata, Argentina
| | - Marcelo Gomes da Silva
- Laboratório de Ciências Físicas, Centro de Ciência Tecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Campos dos Goytacazes, Rio de Janeiro, CEP 28013-602, Brazil
| | - Jurandi G Oliveira
- Laboratório de Melhoramento Genético Vegetal, Centro de Ciências e Tecnologias Agropecuárias, Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Campos dos Goytacazes, Rio de Janeiro, CEP 28013-602, Brazil.
| |
Collapse
|
2
|
Rashid FAA, Crisp PA, Zhang Y, Berkowitz O, Pogson BJ, Day DA, Masle J, Dewar RC, Whelan J, Atkin OK, Scafaro AP. Molecular and physiological responses during thermal acclimation of leaf photosynthesis and respiration in rice. PLANT, CELL & ENVIRONMENT 2020; 43:594-610. [PMID: 31860752 DOI: 10.1111/pce.13706] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 12/15/2019] [Accepted: 12/16/2019] [Indexed: 05/24/2023]
Abstract
To further our understanding of how sustained changes in temperature affect the carbon economy of rice (Oryza sativa), hydroponically grown plants of the IR64 cultivar were developed at 30°C/25°C (day/night) before being shifted to 25/20°C or 40/35°C. Leaf messenger RNA and protein abundance, sugar and starch concentrations, and gas-exchange and elongation rates were measured on preexisting leaves (PE) already developed at 30/25°C or leaves newly developed (ND) subsequent to temperature transfer. Following a shift in growth temperature, there was a transient adjustment in metabolic gene transcript abundance of PE leaves before homoeostasis was reached within 24 hr, aligning with Rdark (leaf dark respiratory CO2 release) and An (net CO2 assimilation) changes. With longer exposure, the central respiratory protein cytochrome c oxidase (COX) declined in abundance at 40/35°C. In contrast to Rdark , An was maintained across the three growth temperatures in ND leaves. Soluble sugars did not differ significantly with growth temperature, and growth was fastest with extended exposure at 40/35°C. The results highlight that acclimation of photosynthesis and respiration is asynchronous in rice, with heat-acclimated plants exhibiting a striking ability to maintain net carbon gain and growth when exposed to heat-wave temperatures, even while reducing investment in energy-conserving respiratory pathways.
Collapse
Affiliation(s)
- Fatimah Azzahra Ahmad Rashid
- Australian Research Council Centre of Excellence in Plant Energy Biology, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
- Department of Biology, Faculty of Science and Mathematics, Sultan Idris Education University, Tanjung Malim, Malaysia
| | - Peter A Crisp
- Department of Plant and Microbial Biology, University of Minnesota, Saint Paul, Minnesota
| | - You Zhang
- CSIRO Plant Industry, Canberra, Australian Capital Territory, Australia
| | - Oliver Berkowitz
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Life Science, AgriBio Building, La Trobe University, Melbourne, Victoria, Australia
| | - Barry J Pogson
- Australian Research Council Centre of Excellence in Plant Energy Biology, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - David A Day
- College of Science and Engineering, Flinders University, Adelaide, South Australia, Australia
- Department of Animal, Plant and Soil Sciences, AgriBio Building, La Trobe University, Melbourne, Victoria, Australia
| | - Josette Masle
- Research School of Biology, The Australian National University, Canberra, Australia
| | - Roderick C Dewar
- Research School of Biology, The Australian National University, Canberra, Australia
- Institute for Atmospheric and Earth System Research/Physics, University of Helsinki, Helsinki, Finland
| | - James Whelan
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Life Science, AgriBio Building, La Trobe University, Melbourne, Victoria, Australia
| | - Owen K Atkin
- Australian Research Council Centre of Excellence in Plant Energy Biology, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Andrew P Scafaro
- Australian Research Council Centre of Excellence in Plant Energy Biology, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
| |
Collapse
|
3
|
Liao YWK, Shi K, Fu LJ, Zhang S, Li X, Dong DK, Jiang YP, Zhou YH, Xia XJ, Liang WS, Yu JQ. The reduction of reactive oxygen species formation by mitochondrial alternative respiration in tomato basal defense against TMV infection. PLANTA 2012; 235:225-38. [PMID: 21779957 DOI: 10.1007/s00425-011-1483-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Accepted: 07/07/2011] [Indexed: 05/07/2023]
Abstract
The role of mitochondrial alternative oxidase (AOX) and the relationship between systemic AOX induction, ROS formation, and systemic plant basal defense to Tobacco mosaic virus (TMV) were investigated in tomato plants. The results showed that TMV inoculation significantly increased the level of AOX gene transcripts, ubiquinone reduction levels, pyruvate content, and cyanide-resistant respiration (CN-resistant R) in upper, un-inoculated leaves. Pretreatment with potassium cyanide (KCN, a cytochrome pathway inhibitor) greatly increased CN-resistant R and reduced reactive oxygen species (ROS) formation, while application of salicylhydroxamic acid (SHAM, an AOX inhibitor) blocked the AOX activity and enhanced the production of ROS in the plants. Furthermore, TMV systemic infection was enhanced by SHAM and reduced by KCN pretreatment, as compared with the un-pretreated TMV counterpart. In addition, KCN application significantly diminished TMV-induced increase in antioxidant enzyme activities and dehydroascorbate/total ascorbate pool, while an opposite change was observed with SHAM-pretreated plants. These results suggest that the systemic induction of the mitochondrial AOX pathway plays a critical role in the reduction of ROS to enhance basal defenses. Additional antioxidant systems were also coordinately regulated in the maintenance of the cellular redox homeostasis.
Collapse
Affiliation(s)
- Yang-Wen-Ke Liao
- Department of Horticulture, Zijingang Campus, Zhejiang University, Yuhangtang Road 866, 310058 Hangzhou, People's Republic of China
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
4
|
Stiff MR, Weissinger AK, Danehower DA. Analysis of CoQ10 in cultivated tobacco by a high-performance liquid chromatography-ultraviolet method. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2011; 59:9054-8. [PMID: 21800864 DOI: 10.1021/jf201130z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Coenzyme Q (CoQ) is a naturally occurring lipid-soluble quinone that performs multiple functions in all living cells and has become a popular antioxidant supplement, a coadjuvant in the treatment of heart disease, and the object of study for treating neurodegenerative disorders. Although there are many tools for CoQ analysis of microbial and animal samples, there have been relatively few reports of methods for CoQ analysis of green plants. This work describes a method for the routine analysis of coenzyme Q(10) in green leaf tissue of cultivated Nicotiana tabacum (tobacco) using high-performance liquid chromatography (HPLC) with UV detection. The method was applied to the analysis of CoQ(10) in N. tabacum 'KY14' leaves at different stalk positions representing young lanceolate to senescing leaves, and it was found that CoQ(10) increased as leaf position changed down the stalk from 18.69 to 82.68 μg/g fw. The method was also used to observe CoQ(10) in N. tabacum 'NC55' and N. tabacum 'TN90LC' leaves over time, finding that CoQ(10) leaf content remained relatively stable from 3 to 6 weeks but increased in both cultivars at 8 weeks. This method will likely be useful in the analysis of CoQ(10) in the green leaves of other plant species.
Collapse
Affiliation(s)
- Michael R Stiff
- Department of Crop Science, North Carolina State University, Raleigh, North Carolina 27695-7620, United States
| | | | | |
Collapse
|
5
|
Yoshida K, Watanabe CK, Hachiya T, Tholen D, Shibata M, Terashima I, Noguchi K. Distinct responses of the mitochondrial respiratory chain to long- and short-term high-light environments in Arabidopsis thaliana. PLANT, CELL & ENVIRONMENT 2011; 34:618-28. [PMID: 21251020 DOI: 10.1111/j.1365-3040.2010.02267.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
In order to ensure the cooperative function with the photosynthetic system, the mitochondrial respiratory chain needs to flexibly acclimate to a fluctuating light environment. The non-phosphorylating alternative oxidase (AOX) is a notable respiratory component that may support a cellular redox homeostasis under high-light (HL) conditions. Here we report the distinct acclimatory manner of the respiratory chain to long- and short-term HL conditions and the crucial function of AOX in Arabidopsis thaliana leaves. Plants grown under HL conditions (HL plants) possessed a larger ubiquinone (UQ) pool and a higher amount of cytochrome c oxidase than plants grown under low light conditions (LL plants). These responses in HL plants may be functional for efficient ATP production and sustain the fast plant growth. When LL plants were exposed to short-term HL stress (sHL), the UQ reduction level was transiently elevated. In the wild-type plant, the UQ pool was re-oxidized concomitantly with an up-regulation of AOX. On the other hand, the UQ reduction level of the AOX-deficient aox1a mutant remained high. Furthermore, the plastoquinone pool was also more reduced in the aox1a mutant under such conditions. These results suggest that AOX plays an important role in rapid acclimation of the respiratory chain to sHL, which may support efficient photosynthetic performance.
Collapse
Affiliation(s)
- Keisuke Yoshida
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| | | | | | | | | | | | | |
Collapse
|
6
|
Kamata T, Matsukawa K, Kakizaki Y, Ito K. In vivo redox state of the ubiquinone pool in the spadices of the thermogenic skunk cabbage, Symplocarpus renifolius. JOURNAL OF PLANT RESEARCH 2009; 122:645-649. [PMID: 19462157 DOI: 10.1007/s10265-009-0240-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2008] [Accepted: 04/09/2009] [Indexed: 05/27/2023]
Abstract
In vivo ubiquinone (UQ) reduction levels were determined in thermogenic stigma and post-thermogenic male stages of spadices of the skunk cabbage, Symplocarpus renifolius. In contrast to Arum maculatum, in which the UQ pool is almost fully reduced during thermogenesis, the reduction levels of UQ9 and UQ10 were not affected by the thermogenic status or developmental stage of individual S. renifolius spadices. Moreover, these levels were controlled within the ranges 40-75% and 35-60%, respectively. These results suggest that the reduction state of the UQ pool per se is not primarily involved in thermoregulation in S. renifolius.
Collapse
Affiliation(s)
- Takashi Kamata
- Faculty of Agriculture, Cryobiofrontier Research Center, Iwate University, Ueda, Morioka, Iwate, 020-8550, Japan
| | | | | | | |
Collapse
|
7
|
Wagner AM, Krab K, Wagner MJ, Moore AL. Regulation of thermogenesis in flowering Araceae: the role of the alternative oxidase. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2008; 1777:993-1000. [PMID: 18440298 DOI: 10.1016/j.bbabio.2008.04.001] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2008] [Revised: 03/31/2008] [Accepted: 04/01/2008] [Indexed: 11/24/2022]
Abstract
The inflorescences of several members of the Arum lily family warm up during flowering and are able to maintain their temperature at a constant level, relatively independent of the ambient temperature. The heat is generated via a mitochondrial respiratory pathway that is distinct from the cytochrome chain and involves a cyanide-resistant alternative oxidase (AOX). In this paper we have used flux control analysis to investigate the influence of temperature on the rate of respiration through both cytochrome and alternative oxidases in mitochondria isolated from the appendices of intact thermogenic Arum maculatum inflorescences. Results are presented which indicate that at low temperatures, the dehydrogenases are almost in full control of respiration but as the temperature increases flux control shifts to the AOX. On the basis of these results a simple model of thermoregulation is presented that is applicable to all species of thermogenic plants. The model takes into account the temperature characteristics of the separate components of the plant mitochondrial respiratory chain and the control of each process. We propose that 1) in all aroid flowers AOX assumes almost complete control over respiration, 2) the temperature profile of AOX explains the reversed relationship between ambient temperature and respiration in thermoregulating Arum flowers, 3) the thermoregulation process is the same in all species and 4) variations in inflorescence temperatures can easily be explained by variations in AOX protein concentrations.
Collapse
Affiliation(s)
- Anneke M Wagner
- Institute of Molecular Cell Biology, VU Universiteit, de Boelelaan 1087, 1081 HV Amsterdam, The Netherlands
| | | | | | | |
Collapse
|
8
|
Hu WH, Shi K, Song XS, Xia XJ, Zhou YH, Yu JQ. Different effects of chilling on respiration in leaves and roots of cucumber (Cucumis sativus). PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2006; 44:837-43. [PMID: 17097883 DOI: 10.1016/j.plaphy.2006.10.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2006] [Accepted: 10/09/2006] [Indexed: 05/10/2023]
Abstract
The effects of chilling on respiration (SHAM-resistant, cytochrome pathway and KCN-resistant, alternative pathway), temperature sensitivity, relative electrolyte conductivity, and degrees of oxidative stress (H(2)O(2) and malonaldehyde (MDA) contents) were separately examined in leaves and roots of cucumber (Cucumis sativus L.). After chilling at 8 degrees C for 4 days, both total respiration and KCN-resistant respiration in roots increased at different measurement temperatures. In contrast, SHAM-resistant respiration remained unchanged. In comparison, chilling significantly decreased the total respiration in leaves and this decrease was mostly due to a decrease in SHAM-resistant respiration. Chilling apparently decreased the sensitivity of KCN-resistant respiration to changes of temperature. The reduction levels of ubiquinone pool (UQr/UQt) increased both in chilled leaves and roots whilst pyruvate content increased only in chilled roots, but not in chilled leaves. Furthermore increases of H(2)O(2) and MDA contents were much greater in leaves than in roots. The same trend was also observed for ion leakage from tissues. Taken together, the results suggested that the higher chilling tolerance of roots was associated with their high total respiration and KCN-resistant respiration.
Collapse
Affiliation(s)
- W H Hu
- Department of Horticulture, Huajiachi Campus, Zhejiang University, Kaixuan Road 268, Hangzhou 310029, China.
| | | | | | | | | | | |
Collapse
|
9
|
Castro-Guerrero NA, Jasso-Chávez R, Moreno-Sánchez R. Physiological role of rhodoquinone in Euglena gracilis mitochondria. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2005; 1710:113-21. [PMID: 16325648 DOI: 10.1016/j.bbabio.2005.10.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2005] [Revised: 09/21/2005] [Accepted: 10/11/2005] [Indexed: 11/24/2022]
Abstract
Rhodoquinone (RQ) participates in fumarate reduction under anaerobiosis in some bacteria and some primitive eukaryotes. Euglena gracilis, a facultative anaerobic protist, also possesses significant rhodoquinone-9 (RQ9) content. Growth under low oxygen concentration induced a decrease in cytochromes and ubiquinone-9 (UQ9) content, while RQ9 and fumarate reductase (FR) activity increased. However, in cells cultured under aerobic conditions, a relatively high RQ9 content was also attained together with significant FR activity. In addition, RQ9 purified from E. gracilis mitochondria was able to trigger the activities of cytochrome bc1 complex, bc1-like alternative component and alternative oxidase, although with lower efficiency (higher Km, lower Vm) than UQ9. Moreover, purified E. gracilis mitochondrial NAD+-independent D-lactate dehydrogenase (D-iLDH) showed preference for RQ9 as electron acceptor, whereas L-iLDH and succinate dehydrogenase preferred UQ9. These results indicated a physiological role for RQ9 under aerobiosis and microaerophilia in E. gracilis mitochondria, in which RQ9 mediates electron transfer between D-iLDH and other respiratory chain components, including FR.
Collapse
Affiliation(s)
- Norma A Castro-Guerrero
- Departamento de Bioquímica, Instituto Nacional de Cardiología, Juan Badiano No. 1, Col. Sección XVI, Tlalpan, México 14080, D.F., México.
| | | | | |
Collapse
|
10
|
Castro-Guerrero NA, Krab K, Moreno-Sánchez R. The alternative respiratory pathway of euglena mitochondria. J Bioenerg Biomembr 2005; 36:459-69. [PMID: 15534393 DOI: 10.1023/b:jobb.0000047328.82733.ef] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Mitochondria, isolated from heterotrophic Euglena gracilis , have cyanide-resistant alternative oxidase (AOX) in their respiratory chain. Cells cultured under a variety of oxidative stress conditions (exposure to cyanide, cold, or H2O2) increased the AOX capacity in mitochondria and cells, although it was significant only under cold stress; AOX sensitivity to inhibitors was also increased by cold and cyanide stress. The value of AOX maximal activity reached 50% of total respiration below 20 degrees C, whereas AOX full activity was only 10-30% of total respiration above 20 degrees C. The optimum pH for AOX activity was 6.5 and for the cytochrome pathway was 7.3. GMP, AMP, pyruvate, or DTT did not alter AOX activity. The reduction level of the quinone pool was higher in mitochondria from cold-stressed than from control cells; furthermore, the content of reduced glutathione was lower in cold-stressed cells. Growth in the presence of an AOX inhibitor was not affected in control cells, whereas in cold-stressed cells, growth was diminished by 50%. Cyanide diminished growth in control cells by 50%, but in cold-stressed cells this inhibitor was ineffective. The data suggest that AOX activity is part of the cellular response to oxidative stress in Euglena .
Collapse
|
11
|
Geisler DA, Johansson FI, Svensson ÅS, Rasmusson AG. Antimycin A treatment decreases respiratory internal rotenone-insensitive NADH oxidation capacity in potato leaves. BMC PLANT BIOLOGY 2004; 4:8. [PMID: 15140267 PMCID: PMC424582 DOI: 10.1186/1471-2229-4-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2003] [Accepted: 05/12/2004] [Indexed: 05/20/2023]
Abstract
BACKGROUND The plant respiratory chain contains several energy-dissipating enzymes, these being type II NAD(P)H dehydrogenases and the alternative oxidase, not present in mammals. The physiological functions of type II NAD(P)H dehydrogenases are largely unclear and little is known about their responses to stress. In this investigation, potato plants (Solanum tuberosum L., cv. Desiree) were sprayed with antimycin A, an inhibitor of the cytochrome pathway. Enzyme capacities of NAD(P)H dehydrogenases (EC 1.6.5.3) and the alternative oxidase were then analysed in isolated leaf mitochondria. RESULTS We report a specific decrease in internal rotenone-insensitive NADH dehydrogenase capacity in mitochondria from antimycin A-treated leaves. External NADPH dehydrogenase and alternative oxidase capacities remained unaffected by the treatment. Western blotting revealed no change in protein abundance for two characterised NAD(P)H dehydrogenase homologues, NDA1 and NDB1, nor for two subunits of complex I. The alternative oxidase was at most only slightly increased. Transcript levels of nda1, as well as an expressed sequence tag derived from a previously uninvestigated closely related potato homologue, remained unchanged by the treatment. As compared to the daily rhythm-regulated nda1, the novel homologue displayed steady transcript levels over the time investigated. CONCLUSIONS The internal rotenone-insensitive NADH oxidation decreases after antimycin A treatment of potato leaves. However, the decrease is not due to changes in expression of known nda genes. One consequence of the lower NADH dehydrogenase capacity may be a stabilisation of the respiratory chain reduction level, should the overall capacity of the cytochrome and the alternative pathway be restricted.
Collapse
Affiliation(s)
- Daniela A Geisler
- Dept of Cell and Organism Biology, Lund University, Sölvegatan 35B, Lund, (SE-223 62), Sweden
| | - Fredrik I Johansson
- Dept of Cell and Organism Biology, Lund University, Sölvegatan 35B, Lund, (SE-223 62), Sweden
| | - Å Staffan Svensson
- Dept of Cell and Organism Biology, Lund University, Sölvegatan 35B, Lund, (SE-223 62), Sweden
- Dept of Plant Biology, The Royal Veterinary and Agricultural University, Thorvaldsensvej 40, Frederiksberg C, (DK-1871), Denmark
| | - Allan G Rasmusson
- Dept of Cell and Organism Biology, Lund University, Sölvegatan 35B, Lund, (SE-223 62), Sweden
| |
Collapse
|
12
|
Finnegan PM, Soole KL, Umbach AL. Alternative Mitochondrial Electron Transport Proteins in Higher Plants. PLANT MITOCHONDRIA: FROM GENOME TO FUNCTION 2004. [DOI: 10.1007/978-1-4020-2400-9_9] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
|
13
|
Djajanegara I, Finnegan PM, Mathieu C, McCabe T, Whelan J, Day DA. Regulation of alternative oxidase gene expression in soybean. PLANT MOLECULAR BIOLOGY 2002; 50:735-42. [PMID: 12374304 DOI: 10.1023/a:1019942720636] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Soybean (Glycine max cv. Stevens) suspension cells were used to investigate the expression of the alternative oxidase (Aox) multigene family. Suspension cells displayed very high rates of cyanide-insensitive respiration, but Aox3 was the only isoform detected in untreated cells. Incubation with antimycin A, citrate, salicylic acid or at low temperature (10 degrees C) specifically induced the accumulation of the Aox1 isoform. Aox2 was not observed under any conditions in the cells. Increases in Aox1 protein correlated with increases in Aox1 mRNA. Treatment of soybean cotyledons with norflurazon also induced expression of Aox1. Reactive oxygen species (ROS) were detected upon incubation of cells with antimycin, salicylic acid or at low temperature, but not during incubation with citrate. Aox1 induction by citrate, but not by antimycin, was prevented by including the protein kinase inhibitor staurosporine in the medium. The results suggest that multiple pathways exist in soybean to regulate expression of Aox genes and that Aox1 specifically is induced by a variety of stress and metabolic conditions via at least two independent signal transduction pathways.
Collapse
Affiliation(s)
- Ira Djajanegara
- Plant Molecular Biology Group, School of Biomedical and Chemical Sciences, University of Western Australia, Crawley, Australia
| | | | | | | | | | | |
Collapse
|
14
|
McDonald AE, Sieger SM, Vanlerberghe GC. Methods and approaches to study plant mitochondrial alternative oxidase. PHYSIOLOGIA PLANTARUM 2002; 116:135-143. [PMID: 12354188 DOI: 10.1034/j.1399-3054.2002.1160201.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The alternative oxidase is a non-proton motive 'alternative' to electron transport through the cytochrome pathway. Despite its wasteful nature in terms of energy conservation, the pathway is likely present throughout the plant kingdom and appears to be expressed in most plant tissues. A small alternative oxidase gene family exists, the members of which are differentially expressed in response to environmental, developmental and other cell signals. The alternative oxidase enzyme possesses tight biochemical regulatory properties that determine its ability to compete with the cytochrome pathway for electrons. Studies show that alternative oxidase can be a prominent component of total respiration in important crop species. All these characteristics suggest this pathway plays an important role in metabolism and/or other aspects of cell physiology. This brief review is an introduction to experimental methods and approaches applicable to different areas of alternative oxidase research. We hope it provides a framework for further investigation of this fascinating component of primary plant metabolism.
Collapse
Affiliation(s)
- Allison E. McDonald
- Division of Life Sciences and Department of Botany, University of Toronto at Scarborough, 1265 Military Trail, Scarborough, ON M1C 1A4, Canada
| | | | | |
Collapse
|
15
|
Abstract
• The giant flowers of the parasitic Rafflesia occur in the shade of the forest understorey. They present several characteristics in common with the related species, Rhizanthes lowii, which is a strongly endothermic flower. The possible existence of endothermy in Rafflesia tuan-mudae was investigated here. • The internal and surface temperature of the flowers were continuously monitored with fine thermocouples while radiation fluxes and microclimatic variables were recorded. A computational fluid dynamic model was used to predict the concentrations of CO2 inside the diaphragm of the flower. • It was found that the internal parts of the flower were maintained a few degrees (1-6 K) above air temperature. It was not possible to account for this temperature rise without postulating a significant internal source of heat. It was concluded that R. tuan-mudae is an endothermic flower that generates a maximum of 50-60 W m-2 of heat in the centre of the column. • The possible role of endothermy, CO2 and volatiles as elements in the mimicry of the flower to attract pollinating blowflies is discussed and compared with the related species Rhizanthes lowii.
Collapse
Affiliation(s)
- Sandra Patiño
- Institute of Ecology and Resource Management, The University of Edinburgh, Darwin Building, Mayfield Road, Edinburgh EH9 3JU, UK
- Helsinki Finland
| | - Tuula Aalto
- Department of Physics, University of Helsinki, PO Box 9 (Siltavuorenpenger 20D), University of Helsinki, FIN-0001
| | - Alice A Edwards
- Chemistry Department, Universiti Brunei Darussalam, Jln. Tungku Link, Bandar Seri Begawan BE 1410, Brunei Darussalam; Present address: Alexander von Humboldt Biological Research Institute, Calle 37 #8-40 Mezanine, Bogotá DC, Colombia
| | - John Grace
- Institute of Ecology and Resource Management, The University of Edinburgh, Darwin Building, Mayfield Road, Edinburgh EH9 3JU, UK
| |
Collapse
|
16
|
Juszczuk IM, Wagner AM, Rychter AM. Regulation of alternative oxidase activity during phosphate deficiency in bean roots (Phaseolus vulgaris). PHYSIOLOGIA PLANTARUM 2001; 113:185-192. [PMID: 12060295 DOI: 10.1034/j.1399-3054.2001.1130205.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Cyanide-resistant respiration was studied in mitochondria isolated from the roots of bean plants (Phaseolus vulgaris L. cv. Złota Saxa) grown hydroponically up to 16 days on a phosphate-sufficient (+P, control) or phosphate-deficient (-P) medium. Western blotting indicated that the alternative oxidase (AOX) was present only in its reduced (active) form, both in phosphate-sufficient and phosphate-deficient roots, but in the latter, the amount of AOX protein was greater. Addition of pyruvate to the isolation, washing and reaction media made mitochondria from +P roots cyanide-insensitive, similar to mitochondria from -P roots. The doubled activity of NAD-malic enzyme (NAD-ME) in -P compared with +P root mitochondria may suggest increased pyruvate production in -P mitochondria. Lower cytochrome c oxidase (COX) activity and no uncoupler effect on respiration indicated limited cytochrome chain activity in -P mitochondria. In -P mitochondria, the oxygen uptake decreased and the level of Q reduction increased from 60 to 80%. With no pyruvate present (AOX not fully activated), inhibition of the cytochrome pathway resulted in an increased level of the ratio of reduced ubiquinone (Qr) to total ubiquinone (Qt) (Qr/Qt) in +P mitochondria, but did not change Qr/Qt in -P mitochondria. When pyruvate was present, the kinetics for AOX were similar in mitochondria from -P and +P roots. It is suggested that AOX participation in -P respiration may provide an acclimation to phosphate deficiency. Stabilization of the ubiquinone reduction level by AOX might prevent the harmful effect of an increased formation of reactive oxygen species.
Collapse
Affiliation(s)
- Izabela M. Juszczuk
- Institute of Experimental Plant Biology, University of Warsaw, Miecznikowa 1, PL-02-096 Warsaw, Poland Department of Molecular Cell Physiology, Free University, De Boelelaan 1087, NL-1081 HV Amsterdam, The Netherlands
| | | | | |
Collapse
|
17
|
Millenaar FF, Gonzàlez-Meler MA, Fiorani F, Welschen R, Ribas-Carbo M, Siedow JN, Wagner AM, Lambers H. Regulation of alternative oxidase activity in six wild monocotyledonous species. An in vivo study at the whole root level. PLANT PHYSIOLOGY 2001; 126:376-87. [PMID: 11351100 PMCID: PMC102311 DOI: 10.1104/pp.126.1.376] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2000] [Revised: 10/20/2000] [Accepted: 01/23/2001] [Indexed: 05/17/2023]
Abstract
The activity of the alternative pathway is affected by a number of factors, including the level and reduction state of the alternative oxidase (AOX) protein, and the reduction state of the ubiquinone pool. To investigate the significance of these factors for the rate of alternative respiration in vivo, we studied root respiration of six wild monocotyledonous grass species that were grown under identical controlled conditions. The activity of the alternative pathway was determined using the oxygen isotope fractionation technique. In all species, the AOX protein was invariably in its reduced (high activity) state. There was no correlation between AOX activity and AOX protein concentration, ubiquinone (total, reduced, or oxidized) concentration, or the reduction state of the ubiquinone pool. However, when some of these factors are combined in a linear regression model, a good fit to AOX activity is obtained. The function of the AOX is still not fully understood. It is interesting that we found a positive correlation between the activity of the alternative pathway and relative growth rate; a possible explanation for this correlation is discussed. Inhibition of the AOX (with salicylhydroxamic acid) decreases respiration rates less than the activity present before inhibition (i.e. measured with the 18O-fractionation technique).
Collapse
Affiliation(s)
- F F Millenaar
- Plant Ecophysiology, Utrecht University, Sorbonnelaan 16, 3584 CA Utrecht, The Netherlands.
| | | | | | | | | | | | | | | |
Collapse
|
18
|
Millenaar FF, Roelofs R, Gonzàlez-Meler MA, Siedow JN, Wagner AM, Lambers H. The alternative oxidase in roots of poa annua after transfer from high-light to low-light conditions. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2000; 23:623-632. [PMID: 10972888 DOI: 10.1046/j.1365-313x.2000.00832.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The activity of the alternative pathway can be affected by a number of factors, including the amount and reduction state of the alternative oxidase protein, and the reduction state of the ubiquinone pool. To investigate the importance of these factors in vivo, we manipulated the rate of root respiration by transferring the annual grass Poa annua L. from high-light to low-light conditions, and at the same time from long-day to short-day conditions for four days. As a result of the low-light treatment, the total respiration rate of the roots decreased by 45%, in vitro cytochrome c oxidase capacity decreased by 49%, sugar concentration decreased by 90% and the ubiquinone concentration increased by 31%, relative to control values. The absolute rate of oxygen uptake via the alternative pathway, as determined using the 18O-isotope fractionation technique, did not change. Conversely, the cytochrome pathway activity decreased during the low-light treatment; its activity increased upon addition of exogenous sugars to the roots. Interestingly, no change was observed in the concentration of the alternative oxidase protein or in the reduction state of the protein. Also, there was no change in the reduction state of the ubiquinone pool. In conclusion, the concentration and activity of the alternative oxidase were not changed, even under severe light deprivation.
Collapse
Affiliation(s)
- F F Millenaar
- Plant Ecophysiology, Utrecht University, Sorbonnelaan 16, 3508 TB Utrecht, The Netherlands.
| | | | | | | | | | | |
Collapse
|
19
|
Simons BH, Millenaar FF, Mulder L, Van Loon LC, Lambers H. Enhanced expression and activation of the alternative oxidase during infection of Arabidopsis with Pseudomonas syringae pv tomato. PLANT PHYSIOLOGY 1999; 120:529-38. [PMID: 10364404 PMCID: PMC59291 DOI: 10.1104/pp.120.2.529] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/1998] [Accepted: 02/23/1999] [Indexed: 05/18/2023]
Abstract
Cyanide-resistant ("alternative") respiration was studied in Arabidopsis during incompatible and compatible infection with Pseudomonas syringae pv tomato DC3000. Total leaf respiration increased as the leaves became necrotic, as did the cyanide-resistant component that was sensitive to salicylhydroxamic acid. Infiltration of leaves with an avirulent strain rapidly induced alternative oxidase (AOX) mRNA, whereas the increase was delayed in the compatible combination. The increase in mRNA correlated with the increase in AOX protein. Increased expression was confined to the infected leaves, in contrast to the pathogenesis-related protein-1, which was induced systemically. Virtually all of the AOX protein was in the reduced (high-activity) form. Using transgenic NahG and mutant npr1-1 and etr1-1 plants, we established that the rapid induction of the AOX was associated with necrosis and that ethylene, but not salicylic acid, was required for its induction. Increased pyruvate levels in the infected leaves suggested that increased substrate levels were respired through the alternative pathway; however, in the control leaves and the infected leaves, respiration was not inhibited by salicylhydroxamic acid alone. Increased respiration appeared to be associated primarily with symptom expression rather than resistance reactions.
Collapse
Affiliation(s)
- B H Simons
- Graduate School of Functional Ecology, Department of Plant Ecology and Evolutionary Biology, Section of Plant Pathology, Utrecht University, The Netherlands
| | | | | | | | | |
Collapse
|
20
|
Millenaar FF, Benschop JJ, Wagner AM, Lambers H. The role of the alternative oxidase in stabilizing the in vivo reduction state of the ubiquinone pool and the activation state of the alternative oxidase. PLANT PHYSIOLOGY 1998; 118:599-607. [PMID: 9765546 PMCID: PMC34836 DOI: 10.1104/pp.118.2.599] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
A possible function for the alternative (nonphosphorylating) pathway is to stabilize the reduction state of the ubiquinone pool (Qr/Qt), thereby avoiding an increase in free radical production. If the Qr/Qt were stabilized by the alternative pathway, then Qr/Qt should be less stable when the alternative pathway is blocked. Qr/Qt increased when we exposed roots of Poa annua (L.) to increasing concentrations of KCN (an inhibitor of the cytochrome pathway). However, when salicylhydroxamic acid, an inhibitor of the alternative pathway, was added at the same time, Qr/Qt increased significantly more. Therefore, we conclude that the alternative pathway stabilizes Qr/Qt. Salicylhydroxamic acid increasingly inhibited respiration with increasing concentrations of KCN. In the experiments described here the alternative oxidase protein was invariably in its reduced (high-activity) state. Therefore, changes in the reduction state of the alternative oxidase cannot account for an increase in activity of the alternative pathway upon titration with KCN. The pyruvate concentration in intact roots increased only after the alternative pathway was blocked or the cytochrome pathway was severely inhibited. The significance of the pyruvate concentration and Qr/Qt on the activity of the alternative pathway in intact roots is discussed.
Collapse
Affiliation(s)
- FF Millenaar
- Department of Plant Ecology and Evolutionary Biology, Utrecht University Graduate School of Experimental Plant Science, Sorbonnelaan 16, 3584 CA Utrecht, The Netherlands (F.F.M., J.J.B., H. L.)
| | | | | | | |
Collapse
|
21
|
Wagner, Wagner, Moore. In vivo ubiquinone reduction levels during thermogenesis in araceae. PLANT PHYSIOLOGY 1998; 117:1501-6. [PMID: 9701605 PMCID: PMC34913 DOI: 10.1104/pp.117.4.1501] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/1998] [Accepted: 05/15/1998] [Indexed: 05/18/2023]
Abstract
In vivo ubiquinone (UQ) reduction levels were measured during the development of the inflorescences of Arum maculatum and Amorphophallus krausei. Thermogenesis in A. maculatum spadices appeared not to be confined to a single developmental stage, but occurred during various stages. The UQ pool in both A. maculatum and A. krausei appendices was approximately 90% reduced during thermogenesis. Respiratory characteristics of isolated appendix mitochondria did not change in the period around thermogenesis. Apparently, synthesis of the required enzyme capacity is regulated via a coarse control upon which a fine control of metabolism that regulates the onset of thermogenesis is imposed.
Collapse
Affiliation(s)
- Wagner
- Department of Molecular Cell Physiology, Vrije Universiteit, De Boelelaan 1087, 1081 HV Amsterdam, The Netherlands (A.M.W., M.J.W.)
| | | | | |
Collapse
|
22
|
Millar AH, Atkin OK, Henry B, Farquhar G, Day DA. Analysis of respiratory chain regulation in roots of soybean seedlings. PLANT PHYSIOLOGY 1998; 117:1083-93. [PMID: 9662551 PMCID: PMC34924 DOI: 10.1104/pp.117.3.1083] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/1997] [Accepted: 04/03/1998] [Indexed: 05/18/2023]
Abstract
Changes in the respiratory rate and the contribution of the cytochrome (Cyt) c oxidase and alternative oxidase (COX and AOX, respectively) were investigated in soybean (Glycine max L. cv Stevens) root seedlings using the 18O-discrimination method. In 4-d-old roots respiration proceeded almost entirely via COX, but by d 17 more than 50% of the flux occurred via AOX. During this period the capacity of COX, the theoretical yield of ATP synthesis, and the root relative growth rate all decreased substantially. In extracts from whole roots of different ages, the ubiquinone pool was maintained at 50% to 60% reduction, whereas pyruvate content fluctuated without a consistent trend. In whole-root immunoblots, AOX protein was largely in the reduced, active form at 7 and 17 d but was partially oxidized at 4 d. In isolated mitochondria, Cyt pathway and succinate dehydrogenase capacities and COX I protein abundance decreased with root age, whereas both AOX capacity and protein abundance remained unchanged. The amount of mitochondrial protein on a dry-mass basis did not vary significantly with root age. It is concluded that decreases in whole-root respiration during growth of soybean seedlings can be largely explained by decreases in maximal rates of electron transport via COX. Flux via AOX is increased so that the ubiquinone pool is maintained in a moderately reduced state.
Collapse
|
23
|
Behal RH, Oliver DJ. Biochemical and molecular characterization of fumarase from plants: purification and characterization of the enzyme--cloning, sequencing, and expression of the gene. Arch Biochem Biophys 1997; 348:65-74. [PMID: 9390175 DOI: 10.1006/abbi.1997.0359] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A cDNA EST clone encoding the C-terminal portion of Arabidopsis thaliana fumarase was identified by homology analysis. A fragment of cDNA encoding the N-terminal region of fumarase was amplified from a cDNA library using PCR and cloned. Genomic DNA corresponding to the coding region of fumarase was amplified and cloned. Arabidopsis fumarase was expressed as a chimeric fusion protein and polyclonal antibodies were generated. Fumarase was purified to near-homogeneity (over 600-fold) from etiolated Pisum sativum mitochondria. The identification of fumarase was confirmed by a combination of immunoblot and N-terminal amino acid sequencing. Kinetic analysis of highly purified fumarase yielded a KM(malate) of 0.45 mM and a Vmax(malate) of 650 mumol of fumarate/min/ mg. The pea fumarase was inhibited by the alpha-keto acids pyruvate and alpha-ketoglutarate at low millimolar concentrations. Adenylates were highly inhibitory; the degree of this inhibition was reduced in the presence of Mg2+, suggesting that uncomplexed adenylates are the inhibitory species.
Collapse
Affiliation(s)
- R H Behal
- Department of Botany, Iowa State University, Ames 50011, USA.
| | | |
Collapse
|
24
|
Wagner AM, Wagner MJ. Changes in Mitochondrial Respiratory Chain Components of Petunia Cells during Culture in the Presence of Antimycin A. PLANT PHYSIOLOGY 1997; 115:617-622. [PMID: 12223830 PMCID: PMC158522 DOI: 10.1104/pp.115.2.617] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
When petunia (Petunia hybrida Vilm, cv Rosy Morn) cells are cultured in the presence of 2 [mu]M antimycin A (AA), respiration proceeds mainly via the cyanide-resistant pathway. Cyanide-resistant respiratory rates were higher in mitochondria from AA cells than in control mitochondria. Compared with control cells, an increase in alternative oxidase protein was observed in AA cells, as well as an increase in ubiquinone (UQ) content. A change in the kinetics of succinate dehydrogenase was observed: there was a much higher activity at high UQ reduction in mitochondria from AA cells compared with control mitochondria. No changes were found for external NADH dehydrogenase kinetics. In AA cells in vivo, UQ reduction was only slightly higher than in control cells, indicating that increased electron transport via the alternative pathway can prevent high UQ reduction levels. Moreover, O2 consumption continues at a similar rate as in control cells, preventing O2 danger. These adaptations to stress conditions, in which the cytochrome pathway is restricted, apparently require, in addition to an increase in alternative oxidase protein, a new setup of the relative amounts and/or kinetic parameters of all of the separate components of the respiratory network.
Collapse
Affiliation(s)
- A. M. Wagner
- Department of Physiology and Biochemistry of Plants, Vrije Universiteit, De Boelelaan 1087, 1081 HV Amsterdam, The Netherlands
| | | |
Collapse
|
25
|
Gardeström P, Lernmark U. The contribution of mitochondria to energetic metabolism in photosynthetic cells. J Bioenerg Biomembr 1995; 27:415-21. [PMID: 8595977 DOI: 10.1007/bf02110004] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Mitochondria fulfill important functions in photosynthetic cells not only in darkness but also in light. Mitochondrial oxidative phosphorylation is probably the main mechanism to supply ATP for extrachloroplastic functions in both conditions. Furthermore, during photosynthesis mitochondrial electron transport is important for regulation of the redox balance in the cell. This makes mitochondrial function an integral part of a flexible metabolic system in the photosynthetic cell. This flexibility is probably very important in order to allow the metabolism to override disturbances caused by the changing environment which plants are adapted to.
Collapse
Affiliation(s)
- P Gardeström
- Department of Plant Physiology, Umeå University, Sweden
| | | |
Collapse
|