1
|
Azarin K, Usatov A, Minkina T, Duplii N, Fedorenko A, Plotnikov A, Mandzhieva S, Kumar R, Yong JWH, Sehar S, Rajput VD. Evaluating the phytotoxicological effects of bulk and nano forms of zinc oxide on cellular respiration-related indices and differential gene expression in Hordeum vulgare L. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2024; 282:116670. [PMID: 38981388 DOI: 10.1016/j.ecoenv.2024.116670] [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: 03/27/2024] [Revised: 06/26/2024] [Accepted: 06/28/2024] [Indexed: 07/11/2024]
Abstract
The increasing use of nanoparticles is driving the growth of research on their effects on living organisms. However, studies on the effects of nanoparticles on cellular respiration are still limited. The remodeling of cellular-respiration-related indices in plants induced by zinc oxide nanoparticles (nnZnO) and its bulk form (blZnO) was investigated for the first time. For this purpose, barley (Hordeum vulgare L.) seedlings were grown hydroponically for one week with the addition of test compounds at concentrations of 0, 0.3, 2, and 10 mg mL-1. The results showed that a low concentration (0.3 mg mL-1) of blZnO did not cause significant changes in the respiration efficiency, ATP content, and total reactive oxygen species (ROS) content in leaf tissues. Moreover, a dose of 0.3 mg mL-1 nnZnO increased respiration efficiency in both leaves (17 %) and roots (38 %). Under the influence of blZnO and nnZnO at medium (2 mg mL-1) and high (10 mg mL-1) concentrations, a dose-dependent decrease in respiration efficiency from 28 % to 87 % was observed. Moreover, the negative effect was greater under the influence of nnZnO. The gene transcription of the subunits of the mitochondria electron transport chain (ETC) changed mainly only under the influence of nnZnO in high concentration. Expression of the ATPase subunit gene, atp1, increased slightly (by 36 %) in leaf tissue under the influence of medium and high concentrations of test compounds, whereas in the root tissues, the atp1 mRNA level decreased significantly (1.6-2.9 times) in all treatments. A dramatic decrease (1.5-2.4 times) in ATP content was also detected in the roots. Against the background of overexpression of the AOX1d1 gene, an isoform of alternative oxidase (AOX), the total ROS content in leaves decreased (with the exception of 10 mg mL-1 nnZnO). However, in the roots, where the pressure of the stress factor is higher, there was a significant increase in ROS levels, with a maximum six-fold increase under 10 mg mL-1 nnZnO. A significant decrease in transcript levels of the pentose phosphate pathway and glycolytic enzymes was also shown in the root tissues compared to leaves. Thus, the disruption of oxidative phosphorylation leads to a decrease in ATP synthesis and an increase in ROS production; concomitantly reducing the efficiency of cellular respiration.
Collapse
Affiliation(s)
- Kirill Azarin
- Southern Federal University, Rostov-on-Don 344090, the Russian Federation
| | - Alexander Usatov
- Southern Federal University, Rostov-on-Don 344090, the Russian Federation
| | - Tatiana Minkina
- Southern Federal University, Rostov-on-Don 344090, the Russian Federation
| | - Nadezhda Duplii
- Southern Federal University, Rostov-on-Don 344090, the Russian Federation
| | - Aleksei Fedorenko
- Southern Federal University, Rostov-on-Don 344090, the Russian Federation
| | - Andrey Plotnikov
- Southern Federal University, Rostov-on-Don 344090, the Russian Federation
| | - Saglara Mandzhieva
- Southern Federal University, Rostov-on-Don 344090, the Russian Federation
| | - Rahul Kumar
- Chitkara Centre for Research and Development, Chitkara University, Himachal Pradesh 174103, India
| | - Jean Wan Hong Yong
- Department of Biosystems and Technology, Swedish University of Agricultural Sciences, Alnarp 23456, Sweden.
| | - Shafaque Sehar
- Department of Agronomy, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China.
| | - Vishnu D Rajput
- Southern Federal University, Rostov-on-Don 344090, the Russian Federation.
| |
Collapse
|
2
|
Shen C, Huang B, Hu L, Yuan H, Huang Y, Wang Y, Sun Y, Li Y, Zhang J, Xin J. Comparative transcriptome analysis and Arabidopsis thaliana overexpression reveal key genes associated with cadmium transport and distribution in root of two Capsicum annuum cultivars. JOURNAL OF HAZARDOUS MATERIALS 2024; 465:133365. [PMID: 38163407 DOI: 10.1016/j.jhazmat.2023.133365] [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: 10/29/2023] [Revised: 12/15/2023] [Accepted: 12/22/2023] [Indexed: 01/03/2024]
Abstract
The molecular mechanisms underlying high and low cadmium (Cd) accumulation in hot pepper cultivars remain unclear. In this study, comparative transcriptome analysis of root between high-Cd (J) and low-Cd (Z) cultivars was conducted under hydroponic cultivation with 0 and 0.4 mg/L Cd, respectively. The results showed that J enhanced the root uptake of Cd by elevating the expression of Nramp5 and counteracting Cd toxicity by increasing the expression of genes, such as NIR1, GLN1, and IAA9. Z reduced Cd accumulation by enhancing the cell wall lignin synthesis genes PAL, COMT, 4CL, LAC, and POD and the Cd transporters ABC, MTP1, and DTX1. Elevated expression of genes related to sulfur metabolism was observed in Z, potentially contributing to its ability to detoxify Cd. To investigate the function of CaCOMT1, an Arabidopsis thaliana overexpression line (OE-CaCOMT1) was constructed. The results revealed that OE-CaCOMT1 drastically increased the lignin content by 38-42% and reduced the translocation of Cd to the aboveground parts by 32%. This study provides comprehensive insights into the mechanisms underlying Cd accumulation in hot pepper cultivars using transcriptome analysis. Moreover, this study elucidates the critical function of CaCOMT1, providing a theoretical foundation for the production of low-Cd vegetables for food safety.
Collapse
Affiliation(s)
- Chuang Shen
- School of Chemical and Environmental Engineering, Hunan Institute of Technology, Hengyang 421002, China
| | - Baifei Huang
- School of Chemical and Environmental Engineering, Hunan Institute of Technology, Hengyang 421002, China
| | - Lu Hu
- Hunan Huanbaoqiao Ecology and Environment Engineering Co., Ltd., Changsha 410221, China
| | - Haiwei Yuan
- Hunan Huanbaoqiao Ecology and Environment Engineering Co., Ltd., Changsha 410221, China
| | - Yingying Huang
- School of Chemical and Environmental Engineering, Hunan Institute of Technology, Hengyang 421002, China
| | - Yanbin Wang
- School of Chemical and Environmental Engineering, Hunan Institute of Technology, Hengyang 421002, China
| | - Yingfang Sun
- School of Chemical and Environmental Engineering, Hunan Institute of Technology, Hengyang 421002, China
| | - Yi Li
- School of Chemical and Environmental Engineering, Hunan Institute of Technology, Hengyang 421002, China
| | - Jirong Zhang
- School of Chemical and Environmental Engineering, Hunan Institute of Technology, Hengyang 421002, China
| | - Junliang Xin
- School of Chemical and Environmental Engineering, Hunan Institute of Technology, Hengyang 421002, China.
| |
Collapse
|
3
|
Zhang X, Li F, Ji C, Wu H. Toxicological mechanism of cadmium in the clam Ruditapes philippinarum using combined ionomic, metabolomic and transcriptomic analyses. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 323:121286. [PMID: 36791949 DOI: 10.1016/j.envpol.2023.121286] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 02/08/2023] [Accepted: 02/12/2023] [Indexed: 06/18/2023]
Abstract
Cadmium (Cd) contamination in marine environment poses great risks to the organisms due to its potential adverse effects. In the present study, the toxicological effects and mechanisms of Cd at environmentally relevant concentrations (5 and 50 μg/L) on clam Ruditapes philippinarum after 21 days were investigated by combined ionomic, metabolomic, and transcriptomic analyses. Results showed that the uptake of Cd significantly decreased the concentrations of Cu, Zn, Sr, Se, and Mo in the whole soft tissue from 50 μg/L Cd-treated clams. Significantly negative correlations were observed between Cd and essential elements (Zn, Sr, Se, and Mo). Altered essential elements homeostasis was associated with the gene regulation of transport and detoxification, including ATP-binding cassette protein subfamily B member 1 (ABCB1) and metallothioneins (MT). The crucial contribution of Se to Cd detoxification was also found in clams. Additionally, gene set enrichment analysis showed that Cd could interfere with proteolysis by peptidases and decrease the translation efficiency at 50 μg/L. Cd inhibited lipid metabolism in clams and increased energy demand by up-regulating glycolysis and TCA cycle. Osmotic pressure was regulated by free amino acids, including alanine, glutamate, taurine, and homarine. Meanwhile, significant alterations of some differentially expressed genes, such as dopamine-β-hydroxylase (DBH), neuroligin (NLGN), NOTCH 1, and chondroitin sulfate proteoglycan 1 (CSPG1) were observed in clams, which implied potential interference with synaptic transmission. Overall, through integrating multiple omics, this study provided new insights into the toxicological mechanisms of Cd, particularly in those mediated by dysregulation of essential element homeostasis.
Collapse
Affiliation(s)
- Xiaoyu Zhang
- CAS Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences (CAS), Shandong Key Laboratory of Coastal Environmental Processes, YICCAS, Yantai, 264003, PR China; University of Chinese Academy of Sciences, Beijing, 100049, PR China
| | - Fei Li
- CAS Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences (CAS), Shandong Key Laboratory of Coastal Environmental Processes, YICCAS, Yantai, 264003, PR China; University of Chinese Academy of Sciences, Beijing, 100049, PR China
| | - Chenglong Ji
- CAS Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences (CAS), Shandong Key Laboratory of Coastal Environmental Processes, YICCAS, Yantai, 264003, PR China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, PR China; Center for Ocean Mega-Science, Chinese Academy of Sciences (CAS), Qingdao, 266071, PR China
| | - Huifeng Wu
- CAS Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences (CAS), Shandong Key Laboratory of Coastal Environmental Processes, YICCAS, Yantai, 264003, PR China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, PR China; Center for Ocean Mega-Science, Chinese Academy of Sciences (CAS), Qingdao, 266071, PR China.
| |
Collapse
|
4
|
Nowicka B. Heavy metal-induced stress in eukaryotic algae-mechanisms of heavy metal toxicity and tolerance with particular emphasis on oxidative stress in exposed cells and the role of antioxidant response. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:16860-16911. [PMID: 35006558 PMCID: PMC8873139 DOI: 10.1007/s11356-021-18419-w] [Citation(s) in RCA: 42] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 12/27/2021] [Indexed: 04/15/2023]
Abstract
Heavy metals is a collective term describing metals and metalloids with a density higher than 5 g/cm3. Some of them are essential micronutrients; others do not play a positive role in living organisms. Increased anthropogenic emissions of heavy metal ions pose a serious threat to water and land ecosystems. The mechanism of heavy metal toxicity predominantly depends on (1) their high affinity to thiol groups, (2) spatial similarity to biochemical functional groups, (3) competition with essential metal cations, (4) and induction of oxidative stress. The antioxidant response is therefore crucial for providing tolerance to heavy metal-induced stress. This review aims to summarize the knowledge of heavy metal toxicity, oxidative stress and antioxidant response in eukaryotic algae. Types of ROS, their formation sites in photosynthetic cells, and the damage they cause to the cellular components are described at the beginning. Furthermore, heavy metals are characterized in more detail, including their chemical properties, roles they play in living cells, sources of contamination, biochemical mechanisms of toxicity, and stress symptoms. The following subchapters contain the description of low-molecular-weight antioxidants and ROS-detoxifying enzymes, their properties, cellular localization, and the occurrence in algae belonging to different clades, as well as the summary of the results of the experiments concerning antioxidant response in heavy metal-treated eukaryotic algae. Other mechanisms providing tolerance to metal ions are briefly outlined at the end.
Collapse
Affiliation(s)
- Beatrycze Nowicka
- Department of Plant Physiology and Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387, Kraków, Poland.
| |
Collapse
|
5
|
Liptáková Ľ, Demecsová L, Valentovičová K, Zelinová V, Tamás L. Early gene expression response of barley root tip to toxic concentrations of cadmium. PLANT MOLECULAR BIOLOGY 2022; 108:145-155. [PMID: 34928487 DOI: 10.1007/s11103-021-01233-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 12/06/2021] [Indexed: 06/14/2023]
Abstract
Already a short-term Cd treatment induces changes in gene expression in barley root tips via IAA and ROS signaling during mild and severe Cd stress, respectively. Even a short, 30 min, Cd treatment of roots induced a considerable alteration in gene expression in the barley root tips within an hour after the treatments. The very early activation of MYB1 transcription factor expression is partially regulated by auxin signaling in mildly stressed seedlings. An increase in allene oxide cyclase and NADPH oxidase expression was a distinguishing feature of root tips response to mild Cd stress and their expression is activated via IAA signaling. Meanwhile, early changes in the level of dehydrin transcripts were detected in moderately and severely stressed root tips, and their induction is related to altered ROS homeostasis in cells. The early activation of glutathione peroxidase expression by mild Cd stress indicates the involvement of IAA in the signaling process. In contrast, early ascorbate peroxidase expression was induced only with Cd treatment causing severe stress and ROS play central roles in its induction. The expression of cysteine protease was activated similarly in both mildly and severely Cd-stressed roots; consequently, both increased IAA and ROS levels take part in the regulation of cysteine protease expression. The Cd-evoked accumulation of BAX Inhibitor-1 mRNA was characteristic for moderately and severely stressed roots. Whereas decreased IAA level did not affect its expression, rotenone-mediated ROS depletion markedly reduced the Cd-induced expression of BAX Inhibitor-1. An early increase of alternative oxidase levels in the root tip cells indicated that the reduction of mitochondrial superoxide generation is an important component of barley root response to severe Cd stress.
Collapse
Affiliation(s)
- Ľubica Liptáková
- Institute of Botany, Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Dúbravská cesta 9, 84523, Bratislava, Slovak Republic
| | - Loriana Demecsová
- Institute of Botany, Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Dúbravská cesta 9, 84523, Bratislava, Slovak Republic
| | - Katarína Valentovičová
- Institute of Botany, Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Dúbravská cesta 9, 84523, Bratislava, Slovak Republic
| | - Veronika Zelinová
- Institute of Botany, Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Dúbravská cesta 9, 84523, Bratislava, Slovak Republic
| | - Ladislav Tamás
- Institute of Botany, Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Dúbravská cesta 9, 84523, Bratislava, Slovak Republic.
| |
Collapse
|
6
|
Alternative Pathway Is Involved in Hydrogen Peroxide-Enhanced Cadmium Tolerance in Hulless Barley Roots. PLANTS 2021; 10:plants10112329. [PMID: 34834692 PMCID: PMC8622811 DOI: 10.3390/plants10112329] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 10/21/2021] [Accepted: 10/23/2021] [Indexed: 11/18/2022]
Abstract
Hulless barley, grown in the Qinghai Tibet Plateau, has a wide range of environmental stress tolerance. Alternative pathway (AP) and hydrogen peroxide (H2O2) are involved in enhancing plant tolerance to environmental stresses. However, the relationship between H2O2 and AP in hulless barley tolerance to cadmium (Cd) stress remains unclear. In the study, the role and relationship of AP and H2O2 under Cd stress were investigated in hulless barley (Kunlun14) and common barley (Ganpi6). Results showed that the expression level of alternative oxidase (AOX) genes (mainly AOX1a), AP capacity (Valt), and AOX protein were clearly induced more in Kunlun14 than in Ganpi 6 under Cd stress; moreover, these parameters were further enhanced by applying H2O2. Malondialdehyde (MDA) content, electrolyte leakage (EL) and NAD(P)H to NAD(P) ratio also increased in Cd-treated roots, especially in Kunlun 14, which can be markedly alleviated by exogenous H2O2. However, this mitigating effect was aggravated by salicylhydroxamic acid (SHAM, an AOX inhibitor), suggesting AP contributes to the H2O2-enhanced Cd tolerance. Further study demonstrated that the effect of SHAM on the antioxidant enzymes and antioxidants was minimal. Taken together, hulless barley has higher tolerance to Cd than common barley; and in the process, AP exerts an indispensable function in the H2O2-enhanced Cd tolerance. AP is mainly responsible for the decrease of ROS levels by dissipating excess reducing equivalents.
Collapse
|
7
|
He J, Liu C, Du M, Zhou X, Hu Z, Lei A, Wang J. Metabolic Responses of a Model Green Microalga Euglena gracilis to Different Environmental Stresses. Front Bioeng Biotechnol 2021; 9:662655. [PMID: 34354984 PMCID: PMC8329484 DOI: 10.3389/fbioe.2021.662655] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 06/10/2021] [Indexed: 12/11/2022] Open
Abstract
Euglena gracilis, a green microalga known as a potential candidate for jet fuel producers and new functional food resources, is highly tolerant to antibiotics, heavy metals, and other environmental stresses. Its cells contain many high-value products, including vitamins, amino acids, pigments, unsaturated fatty acids, and carbohydrate paramylon as metabolites, which change contents in response to various extracellular environments. However, mechanism insights into the cellular metabolic response of Euglena to different toxic chemicals and adverse environmental stresses were very limited. We extensively investigated the changes of cell biomass, pigments, lipids, and paramylon of E. gracilis under several environmental stresses, such as heavy metal CdCl2, antibiotics paromomycin, and nutrient deprivation. In addition, global metabolomics by Ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) was applied to study other metabolites and potential regulatory mechanisms behind the differential accumulation of major high-valued metabolites. This study collects a comprehensive update on the biology of E. gracilis for various metabolic responses to stress conditions, and it will be of great value for Euglena cultivation and high-value [154mm][10mm]Q7metabolite production.
Collapse
Affiliation(s)
- Jiayi He
- Shenzhen Key Laboratory of Marine Bioresources and Eco-environmental Science, Shenzhen Engineering Laboratory for Marine Algal Biotechnology, Guangdong Provincial Key Laboratory for Plant Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, China.,Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, China
| | - ChenChen Liu
- Shenzhen Key Laboratory of Marine Bioresources and Eco-environmental Science, Shenzhen Engineering Laboratory for Marine Algal Biotechnology, Guangdong Provincial Key Laboratory for Plant Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, China
| | - Mengzhe Du
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, China
| | - Xiyi Zhou
- Shenzhen Key Laboratory of Marine Bioresources and Eco-environmental Science, Shenzhen Engineering Laboratory for Marine Algal Biotechnology, Guangdong Provincial Key Laboratory for Plant Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, China
| | - Zhangli Hu
- Shenzhen Key Laboratory of Marine Bioresources and Eco-environmental Science, Shenzhen Engineering Laboratory for Marine Algal Biotechnology, Guangdong Provincial Key Laboratory for Plant Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, China.,Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, China
| | - Anping Lei
- Shenzhen Key Laboratory of Marine Bioresources and Eco-environmental Science, Shenzhen Engineering Laboratory for Marine Algal Biotechnology, Guangdong Provincial Key Laboratory for Plant Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, China
| | - Jiangxin Wang
- Shenzhen Key Laboratory of Marine Bioresources and Eco-environmental Science, Shenzhen Engineering Laboratory for Marine Algal Biotechnology, Guangdong Provincial Key Laboratory for Plant Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, China
| |
Collapse
|
8
|
Demecsová L, Tamás L. Reactive oxygen species, auxin and nitric oxide in metal-stressed roots: toxicity or defence. Biometals 2019; 32:717-744. [PMID: 31541378 DOI: 10.1007/s10534-019-00214-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 08/29/2019] [Indexed: 10/25/2022]
Abstract
The presented review is a summary on the current knowledge about metal induced stress response in plants, focusing on the roles of reactive oxygen species, auxin and nitric oxide in roots. The article focuses mainly on the difference between defence and toxicity symptoms of roots during metal-induced stress. Nowadays, pollution of soils by heavy metals is a rapidly growing issue, which affects agriculture and human health. In order to deal with these problems, we must first understand the basic mechanisms and responses to environmental conditions in plants growing under such conditions. Studies so far show somewhat conflicting data, interpreting the same stress responses as both symptoms of defence and toxicity. Therefore, the aim of this review is to give a report about current knowledge of heavy metal-induced stress research, and also to differentiate between toxicity and defence, and outline the challenges of research, focusing on reactive oxygen and nitrogen species, auxin, and the interplay among them. There are still remaining questions on how reactive oxygen and nitrogen species, as well as auxin, can activate either symptoms of toxicity or defence, and adaptation responses.
Collapse
Affiliation(s)
- Loriana Demecsová
- Institute of Botany, Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Dúbravská cesta 9, 84523, Bratislava, Slovak Republic
| | - Ladislav Tamás
- Institute of Botany, Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Dúbravská cesta 9, 84523, Bratislava, Slovak Republic.
| |
Collapse
|
9
|
Zelinová V, Demecsová L, Tamás L. Impact of antimycin A and myxothiazol on cadmium-induced superoxide, hydrogen peroxide, and nitric oxide generation in barley root tip. PROTOPLASMA 2019; 256:1375-1383. [PMID: 31079230 DOI: 10.1007/s00709-019-01389-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 04/24/2019] [Indexed: 06/09/2023]
Abstract
In order to gain more insight into the involvement of mitochondrial complex III in the Cd-induced stress, we studied the effect of complex III inhibitors, antimycin A (AA), and myxothiazol (MYXO), on the Cd-induced ROS and NO generation in the barley root tip. Short-term exposure of barley roots to either MYXO or AA provoked a dose-dependent increase in both H2O2 and NO formation. In contrast to H2O2 generation, an enhanced superoxide formation in the transition zone of the root was a characteristic feature of AA-treated roots. MYXO and AA co-treatment had an additive effect on the amount of both H2O2 and NO formed in roots. On the other hand, AA-induced superoxide formation was markedly reversed in roots co-treated with MYXO. Both AA and MYXO exacerbated the Cd-mediated H2O2 or NO generation in the root tip. On the contrary, while AA also exacerbated the Cd-induced superoxide generation, MYXO dose-dependently attenuated it. These data provide strong evidence that ROS generation, a very early symptom of Cd toxicity in roots, is originated in mitochondria. Cd, similarly to AA, generates superoxide by blocking the mitochondrial electron transport chain (ETC) at complex III. In turn, the site of Cd-induced NO generation is not associated with complex III, but ROS formed in mitochondria at this third complex of ETC are probably responsible for enhanced NO generation in barley root under Cd stress.
Collapse
Affiliation(s)
- Veronika Zelinová
- Institute of Botany, Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Dúbravská cesta 9, SK-84523, Bratislava, Slovak Republic
| | - Loriana Demecsová
- Institute of Botany, Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Dúbravská cesta 9, SK-84523, Bratislava, Slovak Republic
| | - Ladislav Tamás
- Institute of Botany, Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Dúbravská cesta 9, SK-84523, Bratislava, Slovak Republic.
| |
Collapse
|
10
|
Zimorski V, Rauch C, van Hellemond JJ, Tielens AGM, Martin WF. The Mitochondrion of Euglena gracilis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 979:19-37. [PMID: 28429315 DOI: 10.1007/978-3-319-54910-1_2] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
In the presence of oxygen, Euglena gracilis mitochondria function much like mammalian mitochondria. Under anaerobiosis, E. gracilis mitochondria perform a malonyl-CoA independent synthesis of fatty acids leading to accumulation of wax esters, which serve as the sink for electrons stemming from glycolytic ATP synthesis and pyruvate oxidation. Some components (enzymes and cofactors) of Euglena's anaerobic energy metabolism are found among the anaerobic mitochondria of invertebrates, others are found among hydrogenosomes, the H2-producing anaerobic mitochondria of protists.
Collapse
Affiliation(s)
- Verena Zimorski
- Institute of Molecular Evolution, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Cessa Rauch
- Institute of Molecular Evolution, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Jaap J van Hellemond
- Department of Medical Microbiology and Infectious Diseases, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Aloysius G M Tielens
- Department of Medical Microbiology and Infectious Diseases, Erasmus University Medical Center, Rotterdam, The Netherlands.,Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - William F Martin
- Institute of Molecular Evolution, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany.
| |
Collapse
|
11
|
Tamás L, Mistrík I, Zelinová V. Cadmium activates both diphenyleneiodonium- and rotenone-sensitive superoxide production in barley root tips. PLANTA 2016; 244:1277-1287. [PMID: 27534965 DOI: 10.1007/s00425-016-2587-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 08/11/2016] [Indexed: 06/06/2023]
Abstract
Mild Cd stress-activated diphenyleneiodonium-sensitive superoxide production is utilized in root morphogenic responses, while severe Cd stress-induced robust rotenone-sensitive superoxide generation may lead to cell and root death. In barley, even a few minute exposure of roots to Cd concentration higher than 10 µM evoked a strong superoxide generation in the root transition zone. This superoxide generation was strongly inhibited by the inhibition of mitochondrial electron flow into complex III in the presence of the mitochondrial complex I inhibitor rotenone. Similarly, the superoxide generation induced by antimycin A, an inhibitor of mitochondrial complex III, was considerably reduced by rotenone, suggesting the involvement of complex III also in the severe Cd stress-induced superoxide generation. This severe Cd stress-induced superoxide generation was followed by an extensive cell death in this part of the root tip, which similar to the superoxide generation, was eliminated by rotenone co-treatment. In turn, mild Cd stress-induced diphenyleneiodonium (DPI)-sensitive superoxide generation was observed only in the post-stressed roots, suggesting that it is not directly associated with Cd toxicity. Diphenyleneiodonium, an inhibitor of NADPH oxidase, markedly inhibited the mild Cd stress-induced radial expansion of root apex, indicating that enhanced DPI-sensitive superoxide production is required for rapid isotropic cell growth. Severe Cd stress, probably through the inhibition of complex III, caused a rapid and robust superoxide generation leading to cell and/or root death. By contrast, mild Cd stress did not evoke oxidative stress, and the enhanced DPI-sensitive superoxide generation is utilized in adaptive morphogenic responses.
Collapse
Affiliation(s)
- Ladislav Tamás
- Institute of Botany, Slovak Academy of Sciences, Dúbravská cesta 9, SK-84523, Bratislava, Slovak Republic.
| | - Igor Mistrík
- Institute of Botany, Slovak Academy of Sciences, Dúbravská cesta 9, SK-84523, Bratislava, Slovak Republic
| | - Veronika Zelinová
- Institute of Botany, Slovak Academy of Sciences, Dúbravská cesta 9, SK-84523, Bratislava, Slovak Republic
| |
Collapse
|
12
|
Peng C, Lee JW, Sichani HT, Ng JC. Toxic effects of individual and combined effects of BTEX on Euglena gracilis. JOURNAL OF HAZARDOUS MATERIALS 2015; 284:10-8. [PMID: 25463212 DOI: 10.1016/j.jhazmat.2014.10.024] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 10/11/2014] [Accepted: 10/13/2014] [Indexed: 05/26/2023]
Abstract
BTEX is a group of volatile organic compounds consisting of benzene, toluene, ethylbenzene and xylenes. Environmental contamination of BTEX can occur in the groundwater with their effects on the aquatic organisms and ecosystem being sparsely studied. The aim of this study was to evaluate the toxic effects of individual and mixed BTEX on Euglena gracilis (E. gracilis). We examined the growth rate, morphological changes and chlorophyll contents in E. gracilis Z and its mutant SMZ cells treated with single and mixture of BTEX. BTEX induced morphological change, formation of lipofuscin, and decreased chlorophyll content of E. gracilis Z in a dose response manner. The toxicity of individual BTEX on cell growth and chlorophyll inhibition is in the order of xylenes>ethylbenzene>toluene>benzene. SMZ was found more sensitive to BTEX than Z at much lower concentrations between 0.005 and 5 μM. The combined effect of mixed BTEX on chlorophyll contents was shown to be concentration addition (CA). Results from this study suggested that E. gracilis could be a suitable model for monitoring BTEX in the groundwater and predicting the combined effects on aqueous ecosystem.
Collapse
Affiliation(s)
- Cheng Peng
- The University of Queensland, National Research Centre for Environmental Toxicology (Entox), 39 Kessels Road, Coopers Plains, Brisbane 4108, Australia; Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC-CARE), Mawson Lakes, Adelaide 5095, Australia
| | - Jong-Wha Lee
- Department of Environmental Health, Soonchunhyang University, Asan-si, Chungcheongnam-do 336-745, Republic of Korea
| | - Homa Teimouri Sichani
- The University of Queensland, National Research Centre for Environmental Toxicology (Entox), 39 Kessels Road, Coopers Plains, Brisbane 4108, Australia
| | - Jack C Ng
- The University of Queensland, National Research Centre for Environmental Toxicology (Entox), 39 Kessels Road, Coopers Plains, Brisbane 4108, Australia; Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC-CARE), Mawson Lakes, Adelaide 5095, Australia.
| |
Collapse
|
13
|
Characterization of oxidative phosphorylation enzymes inEuglena gracilisand its white mutant strainWgmZOflL. FEBS Lett 2015; 589:687-94. [DOI: 10.1016/j.febslet.2015.01.035] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Revised: 01/29/2015] [Accepted: 01/30/2015] [Indexed: 02/06/2023]
|
14
|
Peng C, Arthur DM, Sichani HT, Xia Q, Ng JC. Assessing benzene-induced toxicity on wild type Euglena gracilis Z and its mutant strain SMZ. CHEMOSPHERE 2013; 93:2381-2389. [PMID: 24034892 DOI: 10.1016/j.chemosphere.2013.08.037] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Revised: 07/03/2013] [Accepted: 08/10/2013] [Indexed: 06/02/2023]
Abstract
Benzene is a representative member of volatile organic compounds and has been widely used as an industrial solvent. Groundwater contamination of benzene may pose risks to human health and ecosystems. Detection of benzene in the groundwater using chemical analysis is expensive and time consuming. In addition, biological responses to environmental exposures are uninformative using such analysis. Therefore, the aim of this study was to employ a microorganism, Euglena gracilis (E. gracilis) as a putative model to monitor the contamination of benzene in groundwater. To this end, we examined the wild type of E. gracilis Z and its mutant form, SMZ in their growth rate, morphology, chlorophyll content, formation of reactive oxygen species (ROS) and DNA damage in response to benzene exposure. The results showed that benzene inhibited cell growth in a dose response manner up to 48 h of exposure. SMZ showed a greater sensitivity compared to Z in response to benzene exposure. The difference was more evident at lower concentrations of benzene (0.005-5 μM) where growth inhibition occurred in SMZ but not in Z cells. We found that benzene induced morphological changes, formation of lipofuscin, and decreased chlorophyll content in Z strain in a dose response manner. No significant differences were found between the two strains in ROS formation and DNA damage by benzene at concentrations affecting cell growth. Based on these results, we conclude that E. gracilis cells were sensitive to benzene-induced toxicities for certain endpoints such as cell growth rate, morphological change, depletion of chlorophyll. Therefore, it is a potentially suitable model for monitoring the contamination of benzene and its effects in the groundwater.
Collapse
Affiliation(s)
- Cheng Peng
- The University of Queensland, National Research Centre for Environmental Toxicology, 39 Kessels Road, Coopers Plains, Brisbane 4108, Australia; Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC-CARE), Australia
| | | | | | | | | |
Collapse
|
15
|
Vanlerberghe GC. Alternative oxidase: a mitochondrial respiratory pathway to maintain metabolic and signaling homeostasis during abiotic and biotic stress in plants. Int J Mol Sci 2013; 14:6805-47. [PMID: 23531539 PMCID: PMC3645666 DOI: 10.3390/ijms14046805] [Citation(s) in RCA: 415] [Impact Index Per Article: 37.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2013] [Revised: 03/08/2013] [Accepted: 03/12/2013] [Indexed: 02/07/2023] Open
Abstract
Alternative oxidase (AOX) is a non-energy conserving terminal oxidase in the plant mitochondrial electron transport chain. While respiratory carbon oxidation pathways, electron transport, and ATP turnover are tightly coupled processes, AOX provides a means to relax this coupling, thus providing a degree of metabolic homeostasis to carbon and energy metabolism. Beside their role in primary metabolism, plant mitochondria also act as "signaling organelles", able to influence processes such as nuclear gene expression. AOX activity can control the level of potential mitochondrial signaling molecules such as superoxide, nitric oxide and important redox couples. In this way, AOX also provides a degree of signaling homeostasis to the organelle. Evidence suggests that AOX function in metabolic and signaling homeostasis is particularly important during stress. These include abiotic stresses such as low temperature, drought, and nutrient deficiency, as well as biotic stresses such as bacterial infection. This review provides an introduction to the genetic and biochemical control of AOX respiration, as well as providing generalized examples of how AOX activity can provide metabolic and signaling homeostasis. This review also examines abiotic and biotic stresses in which AOX respiration has been critically evaluated, and considers the overall role of AOX in growth and stress tolerance.
Collapse
Affiliation(s)
- Greg C Vanlerberghe
- Department of Biological Sciences and Department of Cell and Systems Biology, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON, M1C1A4, Canada.
| |
Collapse
|
16
|
Metal-induced oxidative stress and plant mitochondria. Int J Mol Sci 2011; 12:6894-918. [PMID: 22072926 PMCID: PMC3211017 DOI: 10.3390/ijms12106894] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Revised: 09/26/2011] [Accepted: 10/05/2011] [Indexed: 12/26/2022] Open
Abstract
A general status of oxidative stress in plants caused by exposure to elevated metal concentrations in the environment coincides with a constraint on mitochondrial electron transport, which enhances ROS accumulation at the mitochondrial level. As mitochondria are suggested to be involved in redox signaling under environmental stress conditions, mitochondrial ROS can initiate a signaling cascade mediating the overall stress response, i.e., damage versus adaptation. This review highlights our current understanding of metal-induced responses in plants, with focus on the production and detoxification of mitochondrial ROS. In addition, the potential involvement of retrograde signaling in these processes will be discussed.
Collapse
|
17
|
Jasso-Chávez R, Pacheco-Rosales A, Lira-Silva E, Gallardo-Pérez JC, García N, Moreno-Sánchez R. Toxic effects of Cr(VI) and Cr(III) on energy metabolism of heterotrophic Euglena gracilis. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2010; 100:329-338. [PMID: 20851473 DOI: 10.1016/j.aquatox.2010.08.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2010] [Revised: 08/10/2010] [Accepted: 08/17/2010] [Indexed: 05/29/2023]
Abstract
To assess the toxic effect of Cr on energy metabolism, heterotrophic Euglena gracilis was grown in a medium that prompts high yield biomass and in the presence of different Cr(VI) or Cr(III) concentrations. The cell growth IC₅₀ value was 12 and >250μM for Cr(VI) and Cr(III), respectively; in these cells chromium was accumulated and a fraction compartmentalized into mitochondria, and synthesis of cysteine and glutathione was induced. Respiration of control isolated mitochondria was strongly inhibited by added Cr(VI) or Cr(III) with L-lactate or succinate as substrates. In turn, cellular and mitochondrial respiration, respiratory Complexes I, III and IV, glycolysis and cytosolic NAD(+)-alcohol and -lactate dehydrogenases from cells cultured with Cr(VI) were significantly lower than control, whereas AOX and external NADH dehydrogenase activities were unaltered or increased, respectively. Addition of Cr(VI) or Cr(III) to isolated mitochondria or cytosol from control- or Cr(VI)-grown cells induced inhibition of respiration, respiratory Complexes III, IV and AOX, and glycolytic pyruvate kinase; whereas Complex I, external NADH dehydrogenase, and other glycolytic enzymes were unaffected. Protein contents of mitochondrial Complexes I, III, IV and V, and ANT were diminished in Cr(VI)-grown cells. Decreased respiration and glycolysis induced by Cr(VI) resulted in lower cellular ATP content. Results suggested that Cr(VI) cytotoxicity altered gene expression (as widely documented) and hence enzyme content, and induced oxidative stress, but it was also related with direct enzyme inhibition; Cr(III) was also cytotoxic although at higher concentrations. These findings establish new paradigms for chromium toxicity: Cr(VI) direct enzyme inhibition and non-innocuous external Cr(III) toxicity.
Collapse
Affiliation(s)
- Ricardo Jasso-Chávez
- Departamento de Bioquímica, Instituto Nacional de Cardiología, Tlalpan, México D.F., Mexico.
| | | | | | | | | | | |
Collapse
|
18
|
Rodríguez-Zavala JS, Ortiz-Cruz MA, Mendoza-Hernández G, Moreno-Sánchez R. Increased synthesis of α-tocopherol, paramylon and tyrosine by Euglena gracilis under conditions of high biomass production. J Appl Microbiol 2010; 109:2160-72. [PMID: 20854454 DOI: 10.1111/j.1365-2672.2010.04848.x] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIMS To analyse the production of different metabolites by dark-grown Euglena gracilis under conditions found to render high cell growth. METHODS AND RESULTS The combination of glutamate (5 g l(-1) ), malate (2 g l(-1) ) and ethanol (10 ml l(-1) ) (GM + EtOH); glutamate (7·15 g l(-1) ) and ethanol (10 ml l(-1) ); or malate (8·16 g l(-1) ), glucose (10·6 g l(-1) ) and NH(4) Cl (1·8 g l(-1) ) as carbon and nitrogen sources, promoted an increase of 5·6, 3·7 and 2·6-fold, respectively, in biomass concentration in comparison with glutamate and malate (GM). In turn, the production of α-tocopherol after 120 h identified by LC-MS was 3·7 ± 0·2, 2·4 ± 0·1 and 2 ± 0·1 mg [g dry weight (DW)](-1) , respectively, while in the control medium (GM) it was 0·72 ± 0·1 mg (g DW)(-1) . For paramylon synthesis, the addition of EtOH or glucose induced a higher production. Amino acids were assayed by RP-HPLC; Tyr a tocopherol precursor and Ala an amino acid with antioxidant activity were the amino acids synthesized at higher concentration. CONCLUSIONS Dark-grown E. gracilis Z is a suitable source for the generation of the biotechnologically relevant metabolites tyrosine, α-tocopherol and paramylon. SIGNIFICANCE AND IMPACT OF THE STUDY By combining different carbon and nitrogen sources and inducing a tolerable stress to the cell by adding ethanol, it was possible to increase the production of biomass, paramylon, α-tocopherol and some amino acids. The concentrations of α-tocopherol achieved in this study are higher than others reported previously for Euglena, plant and algal systems. This work helps to understand the effect of different carbon sources on the synthesis of bio-molecules by E. gracilis and can be used as a basis for future works to improve the production of different metabolites of biotechnological importance by this organism.
Collapse
Affiliation(s)
- J S Rodríguez-Zavala
- Departamento de Bioquímica, Instituto Nacional de Cardiología, México D.F., México.
| | | | | | | |
Collapse
|
19
|
Prado C, Rodríguez-Montelongo L, González JA, Pagano EA, Hilal M, Prado FE. Uptake of chromium by Salvinia minima: effect on plant growth, leaf respiration and carbohydrate metabolism. JOURNAL OF HAZARDOUS MATERIALS 2010; 177:546-553. [PMID: 20080338 DOI: 10.1016/j.jhazmat.2009.12.067] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2009] [Revised: 12/10/2009] [Accepted: 12/13/2009] [Indexed: 05/28/2023]
Abstract
Metabolic responses to chromium (Cr) exposure and metal uptake were investigated using Salvinia minima plants. Cr treatment reduced the dry weight of floating and submerged leaves, while photosynthetic pigments were not affected. Measurements of respiratory oxygen uptake with and without inhibitors (KCN and SHAM) demonstrated that total respiration, alternative oxidase capacity and residual respiration were higher in Cr-treated than in Cr-untreated leaves, but the highest values were observed in floating leaves. Cr affected the soluble sugar content. Sucrose concentration was, in general, higher in Cr-treated than in Cr-untreated leaves, while the glucose concentration showed an inverse pattern. Cr also affected soluble acid invertase activity, but affectation trend was different between both leaves. Highest values of invertase activity were observed in Cr-treated floating leaves. According to our data soluble acid invertase and sucrose seem to be related to alternative oxidase capacity and residual respiration in floating and submerged leaves exposed to Cr. Thereby, this study constitutes an important contribution to understand metabolic relationships between mitochondrial respiration, alternative respiratory pathway and soluble carbohydrates in plants exposed to heavy metals.
Collapse
Affiliation(s)
- Carolina Prado
- Cátedra de Fisiología Vegetal, Facultad de Ciencias Naturales e IML, Universidad Nacional de Tucumán, CP 4000 Tucumán, Argentina
| | | | | | | | | | | |
Collapse
|
20
|
Two-dimensional liquid chromatography technique coupled with mass spectrometry analysis to compare the proteomic response to cadmium stress in plants. J Biomed Biotechnol 2010; 2010:567510. [PMID: 20204056 PMCID: PMC2828102 DOI: 10.1155/2010/567510] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2009] [Revised: 10/09/2009] [Accepted: 12/19/2009] [Indexed: 12/03/2022] Open
Abstract
Plants are useful in studies of metal toxicity, because their physiological responses to different metals are correlated with the metal exposure dose and chemical state. Moreover a network of proteins and biochemical cascades that may lead to a controlled homeostasis of metals has been identified in many plant species. This paper focuses on the global protein variations that occur in a Populus nigra spp. clone (Poli) that has an exceptional tolerance to the presence of cadmium. Protein separation was based on a two-dimensional liquid chromatography technique. A subset of 20 out of 126 peaks were identified as being regulated differently under cadmium stress and were fingerprinted by MALDI-TOF. Proteins that were more abundant in the treated samples were located in the chloroplast and in the mitochondrion, suggesting the importance of these organelles in the response and adaptation to metal stress.
Collapse
|
21
|
Van Aken O, Giraud E, Clifton R, Whelan J. Alternative oxidase: a target and regulator of stress responses. PHYSIOLOGIA PLANTARUM 2009; 137:354-61. [PMID: 19470093 DOI: 10.1111/j.1399-3054.2009.01240.x] [Citation(s) in RCA: 143] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The alternative oxidase (AOX) is found in all plants examined to date, fungi and lower invertebrates. We propose that AOX is not only part of the stress response in plants, but it also plays a central role in defining the stress response. Three lines of evidence support this proposal: (1) The absence of AOX leads to an alteration of stress defences in normal and stress conditions, (2) the expression of AOX is triggered by a variety of signals indicating that it is a common response and (3) AOX acts as a buffer that determines the threshold for the induction of programmed cell death. Therefore, AOX is not only one of many components involved in the defence response, its activity or lack of activity leads to a radical alteration of the defence equilibrium at a cellular level and thus it plays a central role in programming the stress response. This programming role of AOX can be achieved directly by its ability to suppress the induction of reactive oxygen species (ROS) and indirectly by causing changes in the energy status of cells owing to the non-phosphorylating nature of the alternative respiratory pathway. The latter is likely achieved in combination with a variety of alternative NAD(P)H dehydrogenases, that are co-regulated with AOX. Additionally, we explore the possible function of AOX as a component of the stress response beyond the plant frontier.
Collapse
Affiliation(s)
- Olivier Van Aken
- ARC Centre of Excellence Plant Energy Biology, University of Western Australia, 35 Stirling Highway, 6009 Crawley, Western Australia, Australia.
| | | | | | | |
Collapse
|
22
|
McDonald AE. Alternative oxidase: what information can protein sequence comparisons give us? PHYSIOLOGIA PLANTARUM 2009; 137:328-341. [PMID: 19493309 DOI: 10.1111/j.1399-3054.2009.01242.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The finding that alternative oxidase (AOX) is present in most kingdoms of life has resulted in a large number of AOX sequences that are available for analyses. Multiple sequence alignments of AOX proteins from evolutionarily divergent organisms represent a valuable tool and can be used to identify amino acids and domains that may play a role in catalysis, membrane association and post-translational regulation, especially when these data are coupled with the structural model for the enzyme. I validate the use of this approach by demonstrating that it detects the conserved glutamate and histidine residues in AOX that initially led to its identification as a di-iron carboxylate protein and the generation of a structural model for the protein. A comparative analysis using a larger dataset identified 35 additional amino acids that are conserved in all AOXs examined, 30 of which have not been investigated to date. I hypothesize that these residues will be involved in the quinol terminal oxidase activity or membrane association of AOX. Major differences in AOX protein sequences between kingdoms are revealed, and it is hypothesized that two angiosperm-specific domains may be responsible for the non-covalent dimerization of AOX, whereas two indels in the aplastidic AOXs may play a role in their post-translational regulation. A scheme for predicting whether a particular AOX protein will be recognized by the alternative oxidase monoclonal antibody generated against the AOX of Sauromatum guttatum (Voodoo lily) is presented. The number of functional sites in AOX is greater than expected, and determining the structure of AOX will prove extremely valuable to future research.
Collapse
Affiliation(s)
- Allison E McDonald
- Department of Biology, The University of Western Ontario, 1151 Richmond St. N., London, Ontario N6A5B7, Canada.
| |
Collapse
|
23
|
Expression of the Ciona intestinalis alternative oxidase (AOX) in Drosophila complements defects in mitochondrial oxidative phosphorylation. Cell Metab 2009; 9:449-60. [PMID: 19416715 DOI: 10.1016/j.cmet.2009.03.004] [Citation(s) in RCA: 127] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2008] [Revised: 11/27/2008] [Accepted: 03/11/2009] [Indexed: 11/20/2022]
Abstract
Defects in mitochondrial OXPHOS are associated with diverse and mostly intractable human disorders. The single-subunit alternative oxidase (AOX) found in many eukaryotes, but not in arthropods or vertebrates, offers a potential bypass of the OXPHOS cytochrome chain under conditions of pathological OXPHOS inhibition. We have engineered Ciona intestinalis AOX for conditional expression in Drosophila melanogaster. Ubiquitous AOX expression produced no detrimental phenotype in wild-type flies. However, mitochondrial suspensions from AOX-expressing flies exhibited a significant cyanide-resistant substrate oxidation, and the flies were partially resistant to both cyanide and antimycin. AOX expression was able to complement the semilethality of partial knockdown of both cyclope (COXVIc) and the complex IV assembly factor Surf1. It also rescued the locomotor defect and excess mitochondrial ROS production of flies mutated in dj-1beta, a Drosophila homolog of the human Parkinson's disease gene DJ1. AOX appears to offer promise as a wide-spectrum therapeutic tool in OXPHOS disorders.
Collapse
|