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Bundgaard A, Borowiec BG, Lau GY. Are reactive oxygen species always bad? Lessons from hypoxic ectotherms. J Exp Biol 2024; 227:jeb246549. [PMID: 38533673 DOI: 10.1242/jeb.246549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/28/2024]
Abstract
Oxygen (O2) is required for aerobic energy metabolism but can produce reactive oxygen species (ROS), which are a wide variety of oxidant molecules with a range of biological functions from causing cell damage (oxidative distress) to cell signalling (oxidative eustress). The balance between the rate and amount of ROS generated and the capacity for scavenging systems to remove them is affected by several biological and environmental factors, including oxygen availability. Ectotherms, and in particular hypoxia-tolerant ectotherms, are hypothesized to avoid oxidative damage caused by hypoxia, although it is unclear whether this translates to an increase in ecological fitness. In this Review, we highlight the differences between oxidative distress and eustress, the current mechanistic understanding of the two and how they may affect ectothermic physiology. We discuss the evidence of occurrence of oxidative damage with hypoxia in ectotherms, and that ectotherms may avoid oxidative damage through (1) high levels of antioxidant and scavenging systems and/or (2) low(ering) levels of ROS generation. We argue that the disagreements in the literature as to how hypoxia affects antioxidant enzyme activity and the variable metabolism of ectotherms makes the latter strategy more amenable to ectotherm physiology. Finally, we argue that observed changes in ROS production and oxidative status with hypoxia may be a signalling mechanism and an adaptive strategy for ectotherms encountering hypoxia.
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Affiliation(s)
- Amanda Bundgaard
- University of Cologne, CECAD, Joseph-Stelzmann-Straße 26, DE-50931 Köln, Germany
- Aarhus University, Department of Biology, CF Moellers Alle 3, DK-8000 Aarhus C, Denmark
| | - Brittney G Borowiec
- Wilfrid Laurier University, Department of Biology, 75 University Ave. W., Waterloo, ON, Canada, N2L 3C5
| | - Gigi Y Lau
- University of British Columbia, Department of Zoology, 6270 University Blvd, Vancouver, BC, Canada, V6T 1Z4
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Yin Z, Liu Y, Li Y, Yuan C, Tian Y. Mitochondria of Live Mizuhopecten yessoensis Scallops Can Sensitively Respond to Quality Changes during Dry/Reimmersed Storage as Determined by TMT-Labeled Proteomic Analysis. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:12609-12617. [PMID: 37566884 DOI: 10.1021/acs.jafc.3c02364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/13/2023]
Abstract
Dry/reimmersed storage is often used in the transportation of live scallops. In this study, tandem mass tag (TMT)-labeled protein omics were used to quantitatively analyze the protein changes in scallops during dry/reimmersed stress. The results showed that during dry storage, scallops maintained cellular redox homeostasis through the upregulation of SCO1-like protein and thioredoxin domain-containing protein and reduced organic acids from the ATP synthetic process by the downregulation of NADH dehydrogenase, thereby reducing the damage caused during dry storage. During reimmersed storage, mitochondrial proteins underwent very sensitive changes. By upregulating aerobic respiration-related proteins (including proteins involved in glucose phosphate metabolism, glyceraldehyde 3-phosphate metabolism, etc.), the ATP synthesis ability was improved. However, the damage to the mitochondrial structure by dry storage could not be completely recovered, even by reimmersion. This included some apoptosis-related proteins that were obviously upregulated. In summary, compared with ATP-related indexes, mitochondria can respond more sensitively to dry storage stress.
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Affiliation(s)
- Zhongzhuan Yin
- College of Food Science and Engineering, Dalian Ocean University, Dalian 116023, Liaoning, China
| | - Yang Liu
- College of Food Science and Engineering, Dalian Ocean University, Dalian 116023, Liaoning, China
| | - Yaxuan Li
- College of Food Science and Engineering, Dalian Ocean University, Dalian 116023, Liaoning, China
| | - Chunhong Yuan
- United Graduate School of Agricultural Sciences, Iwate University, Ueda 3-18-8, Morioka, Iwate 020-88550, Japan
| | - Yuanyong Tian
- College of Food Science and Engineering, Dalian Ocean University, Dalian 116023, Liaoning, China
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3
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Steffen JBM, Sokolov EP, Bock C, Sokolova IM. Combined effects of salinity and intermittent hypoxia on mitochondrial capacity and reactive oxygen species efflux in the Pacific oyster, Crassostrea gigas. J Exp Biol 2023; 226:jeb246164. [PMID: 37470191 PMCID: PMC10445735 DOI: 10.1242/jeb.246164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 07/12/2023] [Indexed: 07/21/2023]
Abstract
Coastal environments commonly experience fluctuations in salinity and hypoxia-reoxygenation (H/R) stress that can negatively affect mitochondrial functions of marine organisms. Although intertidal bivalves are adapted to these conditions, the mechanisms that sustain mitochondrial integrity and function are not well understood. We determined the rates of respiration and reactive oxygen species (ROS) efflux in the mitochondria of oysters, Crassostrea gigas, acclimated to high (33 psu) or low (15 psu) salinity, and exposed to either normoxic conditions (control; 21% O2) or short-term hypoxia (24 h at <0.01% O2) and subsequent reoxygenation (1.5 h at 21% O2). Further, we exposed isolated mitochondria to anoxia in vitro to assess their ability to recover from acute (∼10 min) oxygen deficiency (<0.01% O2). Our results showed that mitochondria of oysters acclimated to high or low salinity did not show severe damage and dysfunction during H/R stress, consistent with the hypoxia tolerance of C. gigas. However, acclimation to low salinity led to improved mitochondrial performance and plasticity, indicating that 15 psu might be closer to the metabolic optimum of C. gigas than 33 psu. Thus, acclimation to low salinity increased mitochondrial oxidative phosphorylation rate and coupling efficiency and stimulated mitochondrial respiration after acute H/R stress. However, elevated ROS efflux in the mitochondria of low-salinity-acclimated oysters after acute H/R stress indicates a possible trade-off of higher respiration. The high plasticity and stress tolerance of C. gigas mitochondria may contribute to the success of this invasive species and facilitate its further expansion into brackish regions such as the Baltic Sea.
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Affiliation(s)
- Jennifer B. M. Steffen
- Department of Marine Biology, Institute of Biological Sciences, University of Rostock, 18059 Rostock, Germany
| | - Eugene P. Sokolov
- Leibniz Institute for Baltic Research, Leibniz Science Campus Phosphorus Research Rostock, 18119 Warnemünde, Germany
| | - Christian Bock
- Integrative Ecophysiology, Alfred-Wegener-Institute Helmholtz Centre for Polar and Marine Research, 27570 Bremerhaven, Germany
| | - Inna M. Sokolova
- Department of Marine Biology, Institute of Biological Sciences, University of Rostock, 18059 Rostock, Germany
- Department of Maritime Systems, Interdisciplinary Faculty, University of Rostock, 18059 Rostock, Germany
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Steffen JBM, Haider F, Sokolov EP, Bock C, Sokolova IM. Mitochondrial capacity and reactive oxygen species production during hypoxia and reoxygenation in the ocean quahog, Arctica islandica. J Exp Biol 2021; 224:272605. [PMID: 34697625 DOI: 10.1242/jeb.243082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 10/06/2021] [Indexed: 11/20/2022]
Abstract
Oxygen fluctuations are common in marine waters, and hypoxia-reoxygenation (H-R) stress can negatively affect mitochondrial metabolism. The long-lived ocean quahog, Arctica islandica, is known for its hypoxia tolerance associated with metabolic rate depression, yet the mechanisms that sustain mitochondrial function during oxygen fluctuations are not well understood. We used top-down metabolic control analysis (MCA) to determine aerobic capacity and control over oxygen flux in the mitochondria of quahogs exposed to short-term hypoxia (24 h <0.01% O2) and subsequent reoxygenation (1.5 h 21% O2) compared with normoxic control animals (21% O2). We demonstrated that flux capacity of the substrate oxidation and proton leak subsystems were not affected by hypoxia, while the capacity of the phosphorylation subsystem was enhanced during hypoxia associated with a depolarization of the mitochondrial membrane. Reoxygenation decreased the oxygen flux capacity of all three mitochondrial subsystems. Control over oxidative phosphorylation (OXPHOS) respiration was mostly exerted by substrate oxidation regardless of H-R stress, whereas control by the proton leak subsystem of LEAK respiration increased during hypoxia and returned to normoxic levels during reoxygenation. During hypoxia, reactive oxygen species (ROS) efflux was elevated in the LEAK state, whereas it was suppressed in the OXPHOS state. Mitochondrial ROS efflux returned to normoxic control levels during reoxygenation. Thus, mitochondria of A. islandica appear robust to hypoxia by maintaining stable substrate oxidation and upregulating phosphorylation capacity, but remain sensitive to reoxygenation. This mitochondrial phenotype might reflect adaptation of A. islandica to environments with unpredictable oxygen fluctuations and its behavioural preference for low oxygen levels.
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Affiliation(s)
- Jennifer B M Steffen
- Department of Marine Biology, Institute of Biological Sciences, University of Rostock, 18059 Rostock, Germany
| | - Fouzia Haider
- Department of Marine Biology, Institute of Biological Sciences, University of Rostock, 18059 Rostock, Germany
| | - Eugene P Sokolov
- Leibniz Institute for Baltic Research, Leibniz Science Campus Phosphorus Research Rostock, Warnemünde, 18119 Rostock, Germany
| | - Christian Bock
- Integrative Ecophysiology, Alfred-Wegener-Institute Helmholtz Centre for Polar and Marine Research, 27570 Bremerhaven, Germany
| | - Inna M Sokolova
- Department of Marine Biology, Institute of Biological Sciences, University of Rostock, 18059 Rostock, Germany.,Department of Maritime Systems, Interdisciplinary Faculty, University of Rostock, 18059 Rostock, Germany
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Wen Y, Wang J, Liu X, Li S, Hu J, Luo Y. Regulating glycolysis and heat shock proteins in Gannan yaks ( Bos grunniens) in response to hypoxia of the Qinghai-Tibet Plateau. Arch Anim Breed 2021; 64:345-353. [PMID: 34458561 PMCID: PMC8386194 DOI: 10.5194/aab-64-345-2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Accepted: 07/21/2021] [Indexed: 11/11/2022] Open
Abstract
Glycolysis and heat shock proteins (HSPs) play an important role in
hypoxia-intolerant species during hypoxia conditions. This study was
conducted to evaluate the differences of glycolysis and heat shock proteins
(HSPs) in Gannan yaks (Bos grunniens), with the main goal of understanding how the response
to hypoxia changes with altitude. Here, the genes and enzymes of glycolysis
and HSPs were detected in heart, liver, lung, kidney, and longissimus dorsi
from Gannan yaks at different altitude (2500 and 3500 m) using qPCR,
western blot, and enzyme kits. The results showed that the expression of
HIF1A and PDK4 was increased with altitude (P<0.01) in above tissues.
Significantly increased lactate
dehydrogenase (LDH), adenosine triphosphate (ATP), and nicotinamide adenine
dinucleotide (NADH) levels and the ratio of
NADH/NAD+ were also observed in heart, lung, and longissimus dorsi tissues
(P<0.05), as well as a decreased citric acid (CA) level (P<0.05).
Furthermore, we observed significant global increases in the protein and
mRNA expression levels of both the ATP-independent HSP27 and the
ATP-dependent HSP60 during hypoxic conditions (P<0.01). These
findings revealed that hypoxia-reprogrammed glucose metabolism promotes
energy supply via up-regulated glycolysis and weakness of the tricarboxylic acid
(TCA) cycle. HSPs were activated and the prioritization of cytoprotective
protein chaperone functions over energy conservation in yak under hypoxic conditions.
These results are useful to better understand the unique adaptability of yak, allowing them to survive in hypoxia conditions.
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Affiliation(s)
- Yuliang Wen
- Faculty of Animal Science and Technology, Gansu Agricultural University, Gansu Key Laboratory of Herbivorous Animal Biotechnology, Lanzhou 730070, China
| | - Jiqing Wang
- Faculty of Animal Science and Technology, Gansu Agricultural University, Gansu Key Laboratory of Herbivorous Animal Biotechnology, Lanzhou 730070, China
| | - Xiu Liu
- Faculty of Animal Science and Technology, Gansu Agricultural University, Gansu Key Laboratory of Herbivorous Animal Biotechnology, Lanzhou 730070, China
| | - Shaobin Li
- Faculty of Animal Science and Technology, Gansu Agricultural University, Gansu Key Laboratory of Herbivorous Animal Biotechnology, Lanzhou 730070, China
| | - Jiang Hu
- Faculty of Animal Science and Technology, Gansu Agricultural University, Gansu Key Laboratory of Herbivorous Animal Biotechnology, Lanzhou 730070, China
| | - Yuzhu Luo
- Faculty of Animal Science and Technology, Gansu Agricultural University, Gansu Key Laboratory of Herbivorous Animal Biotechnology, Lanzhou 730070, China
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Emersion and Relative Humidity Modulate Stress Response and Recovery Dynamics in Juvenile Mussels ( Perna canaliculus). Metabolites 2021; 11:metabo11090580. [PMID: 34564395 PMCID: PMC8468153 DOI: 10.3390/metabo11090580] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 08/20/2021] [Accepted: 08/24/2021] [Indexed: 12/05/2022] Open
Abstract
The early stages of intertidal mussels, including the green-lipped mussel, Perna canaliculus, face both direct and indirect environmental threats. Stressors may influence physiological status and, ultimately, survival. An understanding of the nature of stress experienced is critical to inform conservation and aquaculture efforts. Here, we investigated oxidative stress dynamics in juvenile P. canaliculus in relation to emersion duration (1–20 h) and relative humidity (RH, 29–98%) by quantifying oxidative damage (protein carbonyls, lipid hydroperoxides, 8-hydroxydeoxyguanosine) and enzymatic antioxidants (superoxide dismutase, catalase, glutathione peroxidase and reductase). Mussels held in low RH during emersion experienced severe water loss (>70%), high mortality (>80%) and increased oxidative damage (35–45% increase compared to control conditions), while mussels held at high RH were not impacted, even after 20 h of air exposure. Following re-immersion, reoxygenation stress resulted in further increases in damage markers in mussels that had experienced dryer emersion conditions; protective action of antioxidants increased steadily during the 10 h re-immersion period, apparently supporting a reduction in damage markers after 1–5 h of immersion. Clearly, conditions during emersion, as well as duration, substantially influence physiological performance and recovery of juvenile mussels. Successful recruitment to intertidal beds or survival in commercial aquaculture operations may be mediated by the nature of emersion stress experienced by these vulnerable juveniles.
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Azizan A, Alfaro AC, Young T, Venter L. Beyond relaxed: magnesium chloride anaesthesia alters the circulatory metabolome of a marine mollusc (Perna canaliculus). Metabolomics 2021; 17:73. [PMID: 34390406 DOI: 10.1007/s11306-021-01820-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 07/14/2021] [Indexed: 11/27/2022]
Abstract
BACKGROUND The New Zealand Green-lipped mussel industry is well-established providing vastly to aquaculture exports. To assess mussel health and reproduction status, visual examination of organs and/or collection of haemolymph is commonly applied. Anesthetics, such as magnesium chloride (MgCl2) can be utilized to prevent muscle contraction and keep shells open during sampling. The specific effects of muscle relaxing agents on baseline metabolism in invertebrates is unknown, but it is evident that molecular, cellular and physiological parameters are altered with these chemical applications. To this end, metabolomics approaches can help elucidate the effects of relaxing agents for better assessment of their use as a research tool. METHODS Adult Green-lipped mussels were anaesthetized for 3 h in a MgCl2 bath, whereafter haemolymph samples were collected and analyzed via gas chromatography-mass spectrometry applying methyl chloroformate alkylation derivatization. RESULTS Anesthetized mussels were characterized as non-responsive to manual manipulation, with open valves, and limited siphoning function. Metabolite profiling revealed significant increases in the abundances of most metabolites with an array of metabolic activities affected, resulting in an energy imbalance driven by anaerobic metabolism with altered amino acids acting as neurotransmitters and osmolytes. CONCLUSION This research is the first to use a metabolomics approach to identify the metabolic consequences of this commonly used bivalve relaxing technique. Ultimately the use of MgCl2 anesthetization as a sampling strategy should be carefully evaluated and managed when performing metabolomics-related research.
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Affiliation(s)
- Awanis Azizan
- Aquaculture Biotechnology Research Group, Department of Applied Ecology, School of Science, Auckland University of Technology, Private Bag 92006, Auckland, 1142, New Zealand
- Faculty of Health and Environmental Sciences, Institute for Applied Ecology New Zealand, School of Applied Sciences, Auckland University of Technology, Private Bag 92006, Auckland, 1142, New Zealand
| | - Andrea C Alfaro
- Aquaculture Biotechnology Research Group, Department of Applied Ecology, School of Science, Auckland University of Technology, Private Bag 92006, Auckland, 1142, New Zealand.
- Faculty of Health and Environmental Sciences, Institute for Applied Ecology New Zealand, School of Applied Sciences, Auckland University of Technology, Private Bag 92006, Auckland, 1142, New Zealand.
| | - Tim Young
- Aquaculture Biotechnology Research Group, Department of Applied Ecology, School of Science, Auckland University of Technology, Private Bag 92006, Auckland, 1142, New Zealand
- Centre for Biomedical & Chemical Sciences, School of Science, Auckland University of Technology, Auckland, New Zealand
- Faculty of Health and Environmental Sciences, Institute for Applied Ecology New Zealand, School of Applied Sciences, Auckland University of Technology, Private Bag 92006, Auckland, 1142, New Zealand
| | - Leonie Venter
- Aquaculture Biotechnology Research Group, Department of Applied Ecology, School of Science, Auckland University of Technology, Private Bag 92006, Auckland, 1142, New Zealand
- Faculty of Health and Environmental Sciences, Institute for Applied Ecology New Zealand, School of Applied Sciences, Auckland University of Technology, Private Bag 92006, Auckland, 1142, New Zealand
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8
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Ouillon N, Sokolov EP, Otto S, Rehder G, Sokolova IM. Effects of variable oxygen regimes on mitochondrial bioenergetics and reactive oxygen species production in a marine bivalve, Mya arenaria. J Exp Biol 2021; 224:jeb.237156. [PMID: 33436367 DOI: 10.1242/jeb.237156] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 01/06/2021] [Indexed: 12/12/2022]
Abstract
Estuarine and coastal benthic organisms often experience fluctuations in oxygen levels that can negatively impact their mitochondrial function and aerobic metabolism. To study these impacts, we exposed a common sediment-dwelling bivalve, the soft-shell clam Mya arenaria, for 21 days to chronic hypoxia (P O2 ∼4.1 kPa), cyclic hypoxia (P O2 ∼12.7-1.9 kPa, mean 5.7 kPa) or normoxia (P O2 ∼21.1 kPa). pH was manipulated to mimic the covariation in CO2/pH and oxygen levels in coastal hypoxic zones. Mitochondrial respiration, including proton leak, the capacity for oxidative phosphorylation (OXPHOS), the maximum activity of the electron transport system (ETS), reactive oxygen species (ROS) production, and activity and oxygen affinity of cytochrome c oxidase (CCO) were assessed. Acclimation to constant hypoxia did not affect the studied mitochondrial traits except for a modest decrease in the OXPHOS coupling efficiency. Cyclic hypoxia had no effect on OXPHOS or ETS capacity, but increased proton leak and lowered mitochondrial OXPHOS coupling efficiency. Furthermore, mitochondria of clams acclimated to cyclic hypoxia had higher rates of ROS generation compared with the clams acclimated to normoxia or chronic hypoxia. CCO activity was upregulated under cyclic hypoxia, but oxygen affinity of CCO did not change. These findings indicate that long-term cyclic hypoxia has a stronger impact on the mitochondria of M. arenaria than chronic hypoxia and might lead to impaired ATP synthesis, higher costs of mitochondrial maintenance and oxidative stress. These changes might negatively affect populations of M. arenaria in the coastal Baltic Sea under increasing hypoxia pressure.
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Affiliation(s)
- Natascha Ouillon
- Department of Marine Biology, Institute of Biological Sciences, University of Rostock, Rostock 18057, Germany
| | - Eugene P Sokolov
- Leibniz Institute for Baltic Research, Leibniz Science Campus Phosphorus Research Rostock, Rostock 18119, Germany
| | - Stefan Otto
- Department of Marine Chemistry, Leibniz Institute for Baltic Research, Rostock 18119, Germany
| | - Gregor Rehder
- Department of Marine Chemistry, Leibniz Institute for Baltic Research, Rostock 18119, Germany
| | - Inna M Sokolova
- Department of Marine Biology, Institute of Biological Sciences, University of Rostock, Rostock 18057, Germany .,Department of Maritime Systems, Interdisciplinary Faculty, University of Rostock, Rostock, Germany
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Belivermiş M, Swarzenski PW, Oberhänsli F, Melvin SD, Metian M. Effects of variable deoxygenation on trace element bioaccumulation and resulting metabolome profiles in the blue mussel (Mytilus edulis). CHEMOSPHERE 2020; 250:126314. [PMID: 32234623 DOI: 10.1016/j.chemosphere.2020.126314] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 02/21/2020] [Accepted: 02/22/2020] [Indexed: 06/11/2023]
Abstract
The dissolved oxygen concentration of the world's oceans has systematically declined by 2% over the past 50 years, and there has been a notable commensurate expansion of the global oxygen minimum zones (OMZs). Such wide-scale ocean deoxygenation affects the distribution of biological communities, impacts the physiology of organisms that may affect their capacity to absorb and process contaminants. Therefore, the bioaccumulation efficiencies of three contrasting radionuclides, 110mAg, 134Cs and 65Zn were investigated using controlled aquaria in the blue mussel Mytilus edulis under three contrasting dissolved oxygen regimes: normoxic; 7.14 mg L-1, reduced oxygen; 3.57 mg L-1 and hypoxic 1.78 mg L-1 conditions. Results indicated that hypoxic conditions diminished 110mAg uptake in the mussel, whereas depuration rates were not affected. Similarly, hypoxia appeared to cause a decrease in the 65Zn bioaccumulation rate, as evidenced by both weakened uptake and rapid elimination rates. Effects of hypoxia on the metabolome of mussels were also explored by untargeted Nuclear Magnetic Resonance (NMR) spectroscopic methods. The metabolic response was characterised by significantly greater abundance of several amino acids, amino sulfonic acids, dicarboxylic acids, carbohydrates and other metabolites in the lowest oxygen treatment, as compared to the higher oxygen treatments. Clearance rates significantly dropped in hypoxic conditions compared to normoxia. Results suggest that hypoxic conditions, and even partly moderate hypoxia, alter ventilation, an-aerobic, oxidative and osmoregulation metabolism of this mussel, which may further influence the trace element bioaccumulation capacity.
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Affiliation(s)
- Murat Belivermiş
- Department of Biology, Faculty of Science, Istanbul University, 34134, Vezneciler, Istanbul, Turkey; International Atomic Energy Agency, Environment Laboratories, 4a Quai Antoine 1er, MC-98000, Principality of Monaco, 98000, Monaco.
| | - Peter W Swarzenski
- International Atomic Energy Agency, Environment Laboratories, 4a Quai Antoine 1er, MC-98000, Principality of Monaco, 98000, Monaco
| | - François Oberhänsli
- International Atomic Energy Agency, Environment Laboratories, 4a Quai Antoine 1er, MC-98000, Principality of Monaco, 98000, Monaco
| | - Steven D Melvin
- Australian Rivers Institute, School of Environment and Science, Griffith University, Southport, Queensland, 4215, Australia
| | - Marc Metian
- International Atomic Energy Agency, Environment Laboratories, 4a Quai Antoine 1er, MC-98000, Principality of Monaco, 98000, Monaco.
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10
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Effects of hypoxia and reoxygenation on intermediary metabolite homeostasis of marine bivalves Mytilus edulis and Crassostrea gigas. Comp Biochem Physiol A Mol Integr Physiol 2020; 242:110657. [DOI: 10.1016/j.cbpa.2020.110657] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 01/08/2020] [Accepted: 01/08/2020] [Indexed: 02/06/2023]
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11
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Sokolova IM, Sokolov EP, Haider F. Mitochondrial Mechanisms Underlying Tolerance to Fluctuating Oxygen Conditions: Lessons from Hypoxia-Tolerant Organisms. Integr Comp Biol 2020; 59:938-952. [PMID: 31120535 DOI: 10.1093/icb/icz047] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Oxygen (O2) is essential for most metazoan life due to its central role in mitochondrial oxidative phosphorylation (OXPHOS), which generates >90% of the cellular adenosine triphosphate. O2 fluctuations are an ultimate mitochondrial stressor resulting in mitochondrial damage, energy deficiency, and cell death. This work provides an overview of the known and putative mechanisms involved in mitochondrial tolerance to fluctuating O2 conditions in hypoxia-tolerant organisms including aquatic and terrestrial vertebrates and invertebrates. Mechanisms of regulation of the mitochondrial OXPHOS and electron transport system (ETS) (including alternative oxidases), sulphide tolerance, regulation of redox status and mitochondrial quality control, and the potential role of hypoxia-inducible factor (HIF) in mitochondrial tolerance to hypoxia are discussed. Mitochondrial phenotypes of distantly related animal species reveal common features including conservation and/or anticipatory upregulation of ETS capacity, suppression of reactive oxygen species (ROS)-producing electron flux through ubiquinone, reversible suppression of OXPHOS activity, and investment into the mitochondrial quality control mechanisms. Despite the putative importance of oxidative stress in adaptations to hypoxia, establishing the link between hypoxia tolerance and mitochondrial redox mechanisms is complicated by the difficulties of establishing the species-specific concentration thresholds above which the damaging effects of ROS outweigh their potentially adaptive signaling function. The key gaps in our knowledge about the potential mechanisms of mitochondrial tolerance to hypoxia include regulation of mitochondrial biogenesis and fusion/fission dynamics, and HIF-dependent metabolic regulation that require further investigation in hypoxia-tolerant species. Future physiological, molecular and genetic studies of mitochondrial responses to hypoxia, and reoxygenation in phylogenetically diverse hypoxia-tolerant species could reveal novel solutions to the ubiquitous and metabolically severe problem of O2 deficiency and would have important implications for understanding the evolution of hypoxia tolerance and the potential mitigation of pathological states caused by O2 fluctuations.
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Affiliation(s)
- Inna M Sokolova
- Department of Marine Biology, University of Rostock, Rostock, Germany.,Department of Maritime Systems, Interdisciplinary Faculty, University of Rostock, Rostock, Germany
| | - Eugene P Sokolov
- Leibniz Institute for Baltic Sea Research, Leibniz ScienceCampus Phosphorus Research Rostock, Warnemünde, Germany
| | - Fouzia Haider
- Department of Marine Biology, University of Rostock, Rostock, Germany
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12
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Lau GY, Arndt S, Murphy MP, Richards JG. Species- and tissue-specific differences in ROS metabolism during exposure to hypoxia and hyperoxia plus recovery in marine sculpins. ACTA ACUST UNITED AC 2019; 222:jeb.206896. [PMID: 31628206 DOI: 10.1242/jeb.206896] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 10/12/2019] [Indexed: 12/16/2022]
Abstract
Animals that inhabit environments that fluctuate in oxygen must not only contend with disruptions to aerobic metabolism, but also the potential effects of reactive oxygen species (ROS). The goal of this study was to compare aspects of ROS metabolism in response to O2 variability (6 h hypoxia or hyperoxia, with subsequent normoxic recovery) in two species of intertidal sculpin fishes (Cottidae, Actinopterygii) that can experience O2 fluctuations in their natural environment and differ in whole-animal hypoxia tolerance. To assess ROS metabolism, we measured the ratio of glutathione to glutathione disulfide as an indicator of tissue redox environment, MitoP/MitoB ratio to assess in vivo mitochondrial ROS generation, thiobarbituric acid reactive substances (TBARS) for lipid peroxidation, and total oxidative scavenging capacity (TOSC) in the liver, brain and gill. In the brain, the more hypoxia-tolerant O ligocottus maculosus showed large increases in TBARS levels following hypoxia and hyperoxia exposure that were generally not associated with large changes in mitochondrial H2O2 In contrast, the less-tolerant S corpaenichthys marmoratus showed no significant changes in TBARS or mitochondrial H2O2 in the brain. More moderate increases were observed in the liver and gill of O. maculosus exposed to hypoxia and hyperoxia with normoxic recovery, whereas S. marmoratus had a greater response to O2 variability in these tissues compared with the brain. Our results show a species- and tissue-specific relationship between hypoxia tolerance and ROS metabolism.
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Affiliation(s)
- Gigi Y Lau
- Department of Zoology, University of British Columbia, 6270 University Blvd, Vancouver, BC V6T 1Z4, Canada
| | - Sabine Arndt
- MRC Mitochondrial Biology Unit, University of Cambridge, Hills Road, Cambridge CB2 0XY, UK
| | - Michael P Murphy
- MRC Mitochondrial Biology Unit, University of Cambridge, Hills Road, Cambridge CB2 0XY, UK
| | - Jeffrey G Richards
- Department of Zoology, University of British Columbia, 6270 University Blvd, Vancouver, BC V6T 1Z4, Canada
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Sokolova I. Mitochondrial Adaptations to Variable Environments and Their Role in Animals' Stress Tolerance. Integr Comp Biol 2019; 58:519-531. [PMID: 29701785 DOI: 10.1093/icb/icy017] [Citation(s) in RCA: 97] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Mitochondria are the key organelles involved in energy and redox homeostasis, cellular signaling, and survival. Animal mitochondria are exquisitely sensitive to environmental stress, and stress-induced changes in the mitochondrial integrity and function have major consequences for the organismal performance and fitness. Studies in the model organisms such as terrestrial mammals and insects showed that mitochondrial dysfunction is a major cause of injury during pathological conditions and environmental insults such as hypoxia, ischemia-reperfusion, and exposure to toxins. However, animals from highly stressful environments (such as the intertidal zone of the ocean) can maintain mitochondrial integrity and function despite intense and rapid fluctuations in abiotic conditions and associated changes in the intracellular milieu. Recent studies demonstrate that mitochondria of intertidal organisms (including mollusks, crustaceans, and fish) are capable of maintaining activity of mitochondrial electron transport system (ETS), ATP synthesis, and mitochondrial coupling in a broad range of temperature, osmolarity, and ion content. Mitochondria of intertidal organisms such as mollusks are also resistant to hypoxia-reoxygenation injury and show stability or even upregulation of the mitochondrial ETS activity and ATP synthesis capacity during intermittent hypoxia. In contrast, pH optima for mitochondrial ATP synthesis and respiration are relatively narrow in intertidal mollusks and may reflect adaptation to suppress metabolic rate during pH shifts caused by extreme stress. Sensitivity to anthropogenic pollutants (such as trace metals) in intertidal mollusks appears similar to that of other organisms (including mammals) and may reflect the lack of adaptation to these evolutionarily novel stressors. The mechanisms of the exceptional mitochondrial resilience to temperature, salinity, and hypoxic stress are not yet fully understood in intertidal organisms, yet recent studies demonstrate that they may involve rapid modulation of the ETS capacity (possibly due to post-translation modification of mitochondrial proteins), upregulation of antioxidant defenses in anticipation of oxidative stress, and high activity of mitochondrial proteases involved in degradation of damaged mitochondrial proteins. With rapidly developing molecular tools for non-model organisms, future studies of mitochondrial adaptations should pinpoint the molecular sites associated with the passive tolerance and/or active regulation of mitochondrial activity during stress exposures in intertidal organisms, investigate the roles of mitochondria in transduction of stress signals, and explore the interplay between bioenergetics and mitochondrial signaling in facilitating survival in these highly stressful environments.
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Affiliation(s)
- Inna Sokolova
- Department of Marine Biology, Institute for Biological Sciences, University of Rostock, A.-Einstein Str., 3, Rostock 18055, Germany.,Department of Maritime Systems, Interdisciplinary Faculty, University of Rostock, Rostock, Germany
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Effects of hypoxia-reoxygenation stress on mitochondrial proteome and bioenergetics of the hypoxia-tolerant marine bivalve Crassostrea gigas. J Proteomics 2019; 194:99-111. [DOI: 10.1016/j.jprot.2018.12.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 12/03/2018] [Accepted: 12/10/2018] [Indexed: 12/21/2022]
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Nguyen VC, Deck CA, Pamenter ME. Naked mole rats reduce the expression of ATP-dependent but not ATP-independent heat shock proteins in acute hypoxia. J Exp Biol 2019; 222:jeb.211243. [DOI: 10.1242/jeb.211243] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 10/18/2019] [Indexed: 01/02/2023]
Abstract
Naked mole rats (NMRs) are one of the most hypoxia-tolerant mammals identified and putatively experience intermittent and severe hypoxia in their underground burrows. Systemic physiological adaptions to hypoxia have begun to be investigated in this species; however, the cellular adaptations that underlie this tolerance remain poorly understood. Hypoxia compromises cellular energy production; and the maintenance of protein integrity when ATP generation is limited poses a major challenge. Heat shock proteins (HSPs) are cellular chaperones that are cytoprotective during hypoxia and we hypothesized that their expression would increase during acute hypoxia in NMRs. To test this hypothesis, we used qPCR and Western blot approaches to measure changes in gene and protein expression, respectively, of HSP27, HSP40, HSP70, and HSP90 in the brain, heart, liver, and temporalis muscle from NMRs following exposure to normoxia (21% O2) or hypoxia (7% O2 for 4, 12, or 24 hrs). Contrary to our expectations, we observed significant global reductions of ATP-dependant HSP70 and HSP90 (83% and 78%, respectively) after 24 hrs of hypoxia. Conversely, the expression of ATP-independent HSP27 and HSP40 proteins remained constant throughout the 24-hr hypoxic treatment in brain, heart and muscle. However, with prolonged hypoxia (24 hrs), the expression of HSP27 and HSP40 genes in these tissues was also reduced, suggesting that the protein expression of these chaperones may also eventually decrease in hypoxia. These results suggest that energy conservation is prioritized over cytoprotective protein chaperoning in NMR tissues during acute hypoxia. This unique adaptation may help NMRs to minimize energy expenditure while still maintaining proteostasis in hypoxia.
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Affiliation(s)
- Vu Chau Nguyen
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Courtney A. Deck
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
- North Carolina State University, Raleigh, North Carolina, USA
| | - Matthew E. Pamenter
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
- University of Ottawa Brain and Mind Research Institute, Ottawa, ON, Canada
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Seo YJ, Ju HM, Lee SH, Kwak SH, Kang MJ, Yoon JH, Kim CH, Cho HJ. Damage of Inner Ear Sensory Hair Cells via Mitochondrial Loss in a Murine Model of Sleep Apnea With Chronic Intermittent Hypoxia. Sleep 2018; 40:3896165. [PMID: 28934520 DOI: 10.1093/sleep/zsx106] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Study Objectives Investigating the exact pathophysiology of obstructive sleep apnea syndrome (OSAS)-induced hearing loss is critical. We sought to verify the hypothesis that a correlation exists between mitochondrial dysfunction in inner ear hair cells and the auditory dysfunction induced by chronic intermittent hypoxia (CIH) in a murine model of sleep apnea. Methods C57BL/6J adult male mice were randomized to 4 weeks of CIH (n = 12) or normoxia (Sham) (n = 12). Hearing threshold was determined by auditory brainstem response. The activity of mitochondria was compared between CIH and Sham mice. Histological assessment and transmission electron microscopy were performed for assessing morphologic changes in mitochondria. The number of mtDNA copies as well as the levels of PGC1-α, Tfam, and VDAC (voltage-dependent anion channel) were determined in the hair cells of CIH mice. Results We observed that hearing ability in CIH mice was impaired and hair-cell mitochondria in CIH mice were fewer compared to that in Sham and also displayed an aberrant morphology. The mRNA levels of PGC-1α and Tfam were higher in the CIH group than in the Sham group. Moreover, the expression of VDAC was increased in the tectorial membrane, the basilar membrane, and especially in the inner hair cells of CIH mice. Conclusions This study using CIH mice as a model for OSAS provides evidence of an association between OSAS and auditory function alteration, as well as of mitochondria being part of the pathophysiology of hearing impairment. Further investigation is required to determine whether mitochondria could serve as a valid target for preventive or therapeutic purposes.
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Affiliation(s)
- Young Joon Seo
- Department of Otorhinolaryngology, Yonsei University Wonju College of Medicine, Wonju, South Korea
| | - Hyun Mi Ju
- Department of Otorhinolaryngology, Yonsei University Wonju College of Medicine, Wonju, South Korea
| | - Sun Hee Lee
- Department of Otorhinolaryngology, Yonsei University Wonju College of Medicine, Wonju, South Korea
| | - Sang Hyun Kwak
- Department of Otolaryngology, Yonsei University College of Medicine, Seoul, South Korea
| | - Min Jung Kang
- Research Center for Human Natural Defense System, Yonsei University College of Medicine, Seoul, South Korea
| | - Joo-Heon Yoon
- Department of Otolaryngology, Yonsei University College of Medicine, Seoul, South Korea.,Research Center for Human Natural Defense System, Yonsei University College of Medicine, Seoul, South Korea.,The Airway Mucus Institute, Yonsei University College of Medicine, Seoul, South Korea
| | - Chang-Hoon Kim
- Department of Otolaryngology, Yonsei University College of Medicine, Seoul, South Korea.,The Airway Mucus Institute, Yonsei University College of Medicine, Seoul, South Korea
| | - Hyung-Ju Cho
- Department of Otolaryngology, Yonsei University College of Medicine, Seoul, South Korea.,The Airway Mucus Institute, Yonsei University College of Medicine, Seoul, South Korea
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Ecological significance of mitochondrial toxicants. Toxicology 2017; 391:64-74. [DOI: 10.1016/j.tox.2017.07.015] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 07/19/2017] [Accepted: 07/24/2017] [Indexed: 12/15/2022]
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