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Moreira DC, Carvajalino-Fernández JM, Navas CA, de Carvalho JE, Hermes-Lima M. Metabolic and Redox Biomarkers in Skeletal Muscle Underlie Physiological Adaptations of Two Estivating Anuran Species in a South American Semi-arid Environment. Front Physiol 2021; 12:769833. [PMID: 34955885 PMCID: PMC8696254 DOI: 10.3389/fphys.2021.769833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 11/10/2021] [Indexed: 12/05/2022] Open
Abstract
The upregulation of endogenous antioxidants (i.e., preparation for oxidative stress, POS) is part of the biochemical responses underlying the adaptation of animals to adverse environments. Despite the phylogenetic diversity of animals in which POS has been described, most studies focus on animals under controlled laboratory conditions. To address this limitation, we have recently assessed the redox metabolism in the skeletal muscle of Proceratophrys cristiceps estivating under natural settings in the Caatinga. Here, we analyzed biochemical biomarkers in the muscle of another Caatinga species, Pleurodema diplolister, during the rainy (active) and dry (estivating frogs) seasons. We aimed to determine whether P. diplolister enhances its antioxidants during estivation under field conditions and to identify any effect of species on the biochemical responses of P. diplolister and P. cristiceps associated with estivation. To do so, we measured the activities of representative enzymes of intermediary metabolism and antioxidant systems, as well as glutathione and protein carbonyl levels, in the skeletal muscle of P. diplolister. Our findings revealed the suppression of oxidative metabolism and activation of antioxidant enzymes in estivating P. diplolister compared with active specimens. No changes in oxidative damage to proteins were observed and estivating P. diplolister had lower levels of disulfide glutathione (GSSG) and disulfide-to-total glutathione ratio (GSSG/tGSH) than those observed in active individuals. When data for P. diplolister and P. cristiceps were assembled and analyzed, significant effects of species were detected on the activities of metabolic enzymes (citrate synthase, isocitric dehydrogenase, malic enzyme, and creatine kinase) and antioxidant enzymes (catalase, glutathione peroxidase and glutathione transferase), as well as on GSSG/tGSH ratio. Such effects might underlie the physiological and behavioral differences between these two species that share the same microhabitat and survival strategy (i.e., to estivate) during the dry season. Despite some peculiarities, which reflect the physiological diversity of the mechanisms associated with estivation in the Brazilian Caatinga, both P. diplolister and P. cristiceps seem to balance the suppression of oxidative pathways, the maintenance of the capacity of oxygen-independent pathways, and the activation of endogenous antioxidants to preserve muscle function and be ready to resume activity whenever the unpredictable rainy period arrives.
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Affiliation(s)
- Daniel C. Moreira
- Núcleo de Pesquisa em Morfologia e Imunologia Aplicada, Área de Morfologia, Faculdade de Medicina, Universidade de Brasília, Brasília, Brazil
- Departamento de Biologia Celular, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, Brazil
| | - Juan M. Carvajalino-Fernández
- Departamento de Biologia Celular, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, Brazil
- Laboratory of Adaptations to Extreme Environments and Global Change Biology, Universidad Colegio Mayor de Cundinamarca, Bogotá, Colombia
| | - Carlos A. Navas
- Departamento de Fisiologia, Biosciences Institute, Universidade de São Paulo, São Paulo, Brazil
| | - José E. de Carvalho
- Departamento de Ecologia e Biologia Evolutiva, Universidade Federal de São Paulo, Diadema, Brazil
| | - Marcelo Hermes-Lima
- Departamento de Biologia Celular, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, Brazil
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Physiology: An Important Tool to Assess the Welfare of Aquatic Animals. BIOLOGY 2021; 10:biology10010061. [PMID: 33467525 PMCID: PMC7830356 DOI: 10.3390/biology10010061] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Revised: 01/11/2021] [Accepted: 01/13/2021] [Indexed: 12/19/2022]
Abstract
Simple Summary Ensuring a good quality of life for animals is a matter of concern. Welfare assessment has been quite well developed for many terrestrial species, but it is less well characterized for aquatic animals. Classic methodologies, such as behavioral observation, seem unable to improve the wellbeing of aquatic animals when used alone, mainly due to the large number of species and the difficulty to obtain comparative results among taxa. For this reason, it is necessary to identify more methodologies that may be common to the main aquatic taxa of interest to humans: Fish, cephalopods, and crustaceans. Here we present a physiological framework for these taxa as a proxy to evaluate aquatic animal welfare. Physiology is a useful tool in this regard, since animals maintain their homeostasis in a range of values determined for each parameter. Changes occur depending on the type and degree of stress to which animals are subjected. Therefore, understanding the physiology of stress can offer information that helps improve the welfare of aquatic animals. Abstract The assessment of welfare in aquatic animals is currently under debate, especially concerning those kept by humans. The classic concept of animal welfare includes three elements: The emotional state of the organism (including the absence of negative experiences), the possibility of expressing normal behaviors, and the proper functioning of the organism. While methods for evaluating their emotions (such as fear, pain, and anguish) are currently being developed for aquatic species and understanding the natural behavior of all aquatic taxa that interact with humans is a task that requires more time, the evaluation of internal responses in the organisms can be carried out using analytical tools. This review aims to show the potential of the physiology of crustaceans, cephalopods, elasmobranchs, teleosts, and dipnoans to serve as indicators of their wellbeing. Since the classical methods of assessing welfare are laborious and time-consuming by evaluation of fear, pain, and anguish, the assessment may be complemented by physiological approaches. This involves the study of stress responses, including the release of hormones and their effects. Therefore, physiology may be of help in improving animal welfare.
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Marton A, Kaneko T, Kovalik JP, Yasui A, Nishiyama A, Kitada K, Titze J. Organ protection by SGLT2 inhibitors: role of metabolic energy and water conservation. Nat Rev Nephrol 2020; 17:65-77. [PMID: 33005037 DOI: 10.1038/s41581-020-00350-x] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/18/2020] [Indexed: 12/17/2022]
Abstract
Therapeutic inhibition of the sodium-glucose co-transporter 2 (SGLT2) leads to substantial loss of energy (in the form of glucose) and additional solutes (in the form of Na+ and its accompanying anions) in urine. However, despite the continuously elevated solute excretion, long-term osmotic diuresis does not occur in humans with SGLT2 inhibition. Rather, patients on SGLT2 inhibitor therapy adjust to the reduction in energy availability and conserve water. The metabolic adaptations that are induced by SGLT2 inhibition are similar to those observed in aestivation - an evolutionarily conserved survival strategy that enables physiological adaptation to energy and water shortage. Aestivators exploit amino acids from muscle to produce glucose and fatty acid fuels. This endogenous energy supply chain is coupled with nitrogen transfer for organic osmolyte production, which allows parallel water conservation. Moreover, this process is often accompanied by a reduction in metabolic rate. By comparing aestivation metabolism with the fuel switches that occur during therapeutic SGLT2 inhibition, we suggest that SGLT2 inhibitors induce aestivation-like metabolic patterns, which may contribute to the improvements in cardiac and renal function observed with this class of therapeutics.
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Affiliation(s)
- Adriana Marton
- Programme in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore, Singapore
| | - Tatsuroh Kaneko
- Medicine Division, Nippon Boehringer Ingelheim Co., Ltd, Tokyo, Japan
| | - Jean-Paul Kovalik
- Programme in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore, Singapore
| | - Atsutaka Yasui
- Medicine Division, Nippon Boehringer Ingelheim Co., Ltd, Tokyo, Japan
| | - Akira Nishiyama
- Department of Pharmacology, Faculty of Medicine, Kagawa University, Kagawa, Japan
| | - Kento Kitada
- Programme in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore, Singapore.,Department of Pharmacology, Faculty of Medicine, Kagawa University, Kagawa, Japan
| | - Jens Titze
- Programme in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore, Singapore. .,Division of Nephrology and Hypertension, University Clinic Erlangen, Erlangen, Germany. .,Division of Nephrology, Duke University Medical Center, Durham, NC, USA.
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4
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Abou Anni IS, Zebral YD, Afonso SB, Moreno Abril SI, Lauer MM, Bianchini A. Life-time exposure to waterborne copper III: Effects on the energy metabolism of the killifish Poecilia vivipara. CHEMOSPHERE 2019; 227:580-588. [PMID: 31009864 DOI: 10.1016/j.chemosphere.2019.04.080] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Revised: 04/09/2019] [Accepted: 04/10/2019] [Indexed: 06/09/2023]
Abstract
Copper ions (Cu) are essential to life maintenance, nonetheless, elevated concentrations can be hazardous. Acute and sub-chronic toxic effects of this metal are well known and are usually related to enzymatic inhibition, elevated ROS production and dysfunction of energy metabolism. Despite that, chronic studies are extremely rare. Therefore, the aim of this study was to assess the effects of chronic exposure to 5, 9 and 20 μg/L Cu (28 ad 345 days) on the energy metabolism and survival of the killifish Poecilia vivipara. To accomplish that, we evaluated the activity of enzymes related to aerobic (pyruvate kinase (PK); citrate synthase (CS)) and anaerobic metabolism (lactate dehydrogenase (LDH)) in whole-body (28 days) or in gills, liver and muscle (345 days) of exposed fish. Additionally, whole-body oxygen consumption was evaluated in fish exposed for 28 days and hepatic and muscular expression of genes involved in mitochondrial metabolism (cox I, II and III and atp5a1) was assessed in animals exposed for 345 days. Finally, final survival was evaluated. Following 28 days, Cu did not affect survival neither enzyme activities. However, increased whole-body oxygen consumption was observed in comparison to control condition. After 345 days, 76.8%, 63.9%, 60.9% and 0% survival were observed for control, 5, 9 and 20 μg/L groups, respectively. Animals exposed to 5 and 9 μg/L had a significant reduction in branchial and muscular LDH activity and in hepatic PK activity. Also, exposure to 9 μg/L significantly increased hepatic CS activity. For gene expression, Cu down-regulated muscular cox II (9 μg/L) and III (5 and 9 μg/L), and up-regulated hepatic atp5a1 (9 μg/L). Findings reported in the present study indicate that chronic exposure to Cu induces tissue-specific responses in key aspects of the energetic metabolism. In gills and muscle, Cu leads to reduced energy production through inhibition of anaerobic pathways and mitochondrial respiratory chain. This effect is paralleled by an increased ATP consumption in the liver, characterized by the augmented CS activity and atp5a1 expression. Finally, reduced PK activity indicate that oxidative stress may be involved with the observed outcomes.
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Affiliation(s)
- Iuri Salim Abou Anni
- Programa de Pós-graduação Em Ciências Fisiológicas, Universidade Federal Do Rio Grande, Avenida Itália Km 8, Campus Carreiros, 96203-900, Rio Grande, RS, Brazil
| | - Yuri Dornelles Zebral
- Programa de Pós-graduação Em Ciências Fisiológicas, Universidade Federal Do Rio Grande, Avenida Itália Km 8, Campus Carreiros, 96203-900, Rio Grande, RS, Brazil
| | - Sidnei Braz Afonso
- Instituto de Ciências Biológicas, Universidade Federal Do Rio Grande, Avenida Itália Km 8, Campus Carreiros, 96203-900, Rio Grande, RS, Brazil
| | - Sandra Isabel Moreno Abril
- Programa de Pós-graduação Em Ciências Fisiológicas, Universidade Federal Do Rio Grande, Avenida Itália Km 8, Campus Carreiros, 96203-900, Rio Grande, RS, Brazil
| | - Mariana Machado Lauer
- Instituto de Ciências Biológicas, Universidade Federal Do Rio Grande, Avenida Itália Km 8, Campus Carreiros, 96203-900, Rio Grande, RS, Brazil
| | - Adalto Bianchini
- Programa de Pós-graduação Em Ciências Fisiológicas, Universidade Federal Do Rio Grande, Avenida Itália Km 8, Campus Carreiros, 96203-900, Rio Grande, RS, Brazil; Instituto de Ciências Biológicas, Universidade Federal Do Rio Grande, Avenida Itália Km 8, Campus Carreiros, 96203-900, Rio Grande, RS, Brazil.
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5
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Salin K, Villasevil EM, Anderson GJ, Selman C, Chinopoulos C, Metcalfe NB. The RCR and ATP/O Indices Can Give Contradictory Messages about Mitochondrial Efficiency. Integr Comp Biol 2019; 58:486-494. [PMID: 29982616 DOI: 10.1093/icb/icy085] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Mitochondrial efficiency is typically taken to represent an animal's capacity to convert its resources into ATP. However, the term mitochondrial efficiency, as currently used in the literature, can be calculated as either the respiratory control ratio, RCR (ratio of mitochondrial respiration supporting ATP synthesis to that required to offset the proton leak) or as the amount of ATP generated per unit of oxygen consumed, ATP/O ratio. The question of how flexibility in mitochondrial energy properties (i.e., in rates of respiration to support ATP synthesis and offset proton leak, and in the rate of ATP synthesis) affects these indices of mitochondrial efficiency has tended to be overlooked. Furthermore, little is known of whether the RCR and ATP/O ratio vary in parallel, either among individuals or in response to environmental conditions. Using data from brown trout Salmo trutta we show that experimental conditions affect mitochondrial efficiency, but the apparent direction of change depends on the index chosen: a reduction in food availability was associated with an increased RCR (i.e., increased efficiency) but a decreased ATP/O ratio (decreased efficiency) in liver mitochondria. Moreover, there was a negative correlation across individuals held in identical conditions between their RCR and their ATP/O ratio. These results show that the choice of index of mitochondrial efficiency can produce different, even opposing, conclusions about the capacity of the mitochondria to produce ATP. Neither ratio is necessarily a complete measure of efficiency of ATP production in the living animal (RCR because it contains no assessment of ATP production, and ATP/O because it contains no assessment of respiration to offset the proton leak). Consequently, we suggest that a measure of mitochondrial efficiency obtained nearer to conditions where respiration simultaneously offsets the proton leak and produce ATP would be sensitive to changes in both proton leakage and ATP production, and is thus likely to be more representative of the state of the mitochondria in vivo.
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Affiliation(s)
- Karine Salin
- Institute of Biodiversity, Animal Health and Comparative Medicine, Graham Kerr Building, University of Glasgow, Glasgow G12 8QQ, UK.,Ifremer, Unité de Physiologie Fonctionnelle des Organismes Marins-LEMAR UMR 6530, BP70, Plouzané 29280, France
| | - Eugenia M Villasevil
- Institute of Biodiversity, Animal Health and Comparative Medicine, Graham Kerr Building, University of Glasgow, Glasgow G12 8QQ, UK
| | - Graeme J Anderson
- Institute of Biodiversity, Animal Health and Comparative Medicine, Graham Kerr Building, University of Glasgow, Glasgow G12 8QQ, UK
| | - Colin Selman
- Institute of Biodiversity, Animal Health and Comparative Medicine, Graham Kerr Building, University of Glasgow, Glasgow G12 8QQ, UK
| | - Christos Chinopoulos
- Department of Medical Biochemistry, Semmelweis University, Budapest 1094, Hungary.,MTA-SE Lendület Neurobiochemistry Research Group, Budapest 1094, Hungary
| | - Neil B Metcalfe
- Institute of Biodiversity, Animal Health and Comparative Medicine, Graham Kerr Building, University of Glasgow, Glasgow G12 8QQ, UK
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6
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Turko AJ, Doherty JE, Yin-Liao I, Levesque K, Kruth P, Holden JM, Earley RL, Wright PA. Prolonged survival out of water is linked to a slow pace of life in a selfing amphibious fish. J Exp Biol 2019; 222:jeb.209270. [DOI: 10.1242/jeb.209270] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 11/25/2019] [Indexed: 12/25/2022]
Abstract
Metabolic rate and life history traits vary widely both among and within species reflecting trade-offs in energy allocation, but the proximate and ultimate causes of variation are not well understood. We tested the hypothesis that these trade-offs are mediated by environmental heterogeneity, using isogenic strains of the amphibious fish Kryptolebias marmoratus that vary in the amount of time each can survive out of water. Consistent with pace of life theory, the strain that survived air exposure the longest generally exhibited a “slow” phenotype including the lowest metabolic rate, largest scope for metabolic depression, slowest consumption of energy stores, and least investment in reproduction under standard conditions. Growth rates were fastest in the otherwise “slow” strain, however. We then tested for fitness trade-offs between “fast” and “slow” strains using microcosms where fish were held with either constant water availability or under fluctuating conditions where water was absent for half of the experiment. Under both conditions the “slow” strain grew larger and was in better condition, and under fluctuating conditions the “slow” strain produced more embryos. However, the “fast” strain had larger adult population sizes under both conditions, indicating that fecundity is not the sole determinant of population size in this species. We conclude that genetically based differences in pace of life of amphibious fish determine survival duration out of water. Relatively “slow” fish tended to perform better under conditions of limited water availability, but there was no detectable cost under control conditions. Thus, pace of life differences may reflect a conditionally neutral instead of antagonistic trade-off.
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Affiliation(s)
- Andy J. Turko
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada, N1G 2W1
| | - Justine E. Doherty
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada, N1G 2W1
| | - Irene Yin-Liao
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada, N1G 2W1
| | - Kelly Levesque
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada, N1G 2W1
| | - Perryn Kruth
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada, N1G 2W1
| | - Joseph M. Holden
- Department of Biological Sciences, University of Alabama, Tuscaloosa, AL, USA, 35487
| | - Ryan L. Earley
- Department of Biological Sciences, University of Alabama, Tuscaloosa, AL, USA, 35487
| | - Patricia A. Wright
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada, N1G 2W1
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7
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Hermann BT, Wuertz S, Vanselow KH, Schulz C, Stiller KT. Divergent gene expression in the gills of juvenile turbot (Psetta maxima) exposed to chronic severe hypercapnia indicates dose-dependent increase in intracellular oxidative stress and hypoxia. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2019; 206:72-80. [PMID: 30458405 DOI: 10.1016/j.aquatox.2018.10.023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 10/29/2018] [Accepted: 10/29/2018] [Indexed: 06/09/2023]
Abstract
Elevated concentrations of carbon dioxide are a common stressor for fish and other aquatic animals. In particular, intensive aquaculture can impose prolonged periods of severe environmental hypercapnia, manifold exceeding CO2 concentrations of natural habitats. In order to cope with this stressor, gills are essential and constitute the primary organ in the acclimatization process. Yet, despite a general understanding of changes in ion regulation, not much is known with regard to other cellular mechanisms. In this study, we apply RT-qPCR to investigate changes in the expression of several genes associated with metabolism, stress and immunity within gills of juvenile turbot (Psetta maxima) after an eight-week exposure to different concentrations of CO2 (low = ∼3000 μatm, medium = ∼15,000 μatm and high = ∼25,000 μatm CO2). Histological examination of the gill tissue only found a significant increase of hypertrophied secondary lamella in the highest tested treatment level. gene expression results, on the other hand, implied both, mutual and dose-dependent transcriptional adjustments. Comparable up-regulation of IL-1ß, LMP7 and Grim19 at medium and high hypercapnia indicated an increase of reactive oxygen species (ROS) within gill cells. Simultaneous increase in Akirin and PRDX transcripts at medium CO2 indicated enhanced anti-oxidant activity and regulation of transcription, while reduced mRNA concentrations of COX, EF1α and STAT2 at high CO2 denoted suppressed protein synthesis and reduced metabolic capacity. In addition to upregulated DFAD and ApoE expression, implying compensating repair measures, gills exposed to the highest tested treatment level seemed to operate close to or even beyond their maximum capacity. Thus, fitting the model of capacity limitation, our results provide evidence for accretive intracellular hypoxia and oxidative stress in the gills of turbot, dependent on the level of environmental hypercapnia. Further, genes, such as COX, may be valuable biomarkers when attempting to discriminate between a successful and an overpowered stress response.
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Affiliation(s)
- Bernd T Hermann
- GEOMAR Helmholtz-Centre for Ocean Research Kiel, Düsternbrooker Weg 20, 24105, Kiel, Germany.
| | - Sven Wuertz
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Dept. Ecophysiology and Aquaculture, Müggelseedamm 310, 12587, Berlin, Germany
| | - Klaus H Vanselow
- Research and Technology Centre (FTZ), Kiel University, Hafentörn 1, 25761, Büsum, Germany
| | - Carsten Schulz
- Institute of Animal Breeding and Husbandry, Department for Marine Aquaculture, Kiel University, Hermann-Rodewald-Str. 6, 24118, Kiel, Germany; Gesellschaft für Marine Aquakultur (GMA), Hafentörn 3, 25761, Büsum, Germany
| | - Kevin T Stiller
- Research and Technology Centre (FTZ), Kiel University, Hafentörn 1, 25761, Büsum, Germany; Gesellschaft für Marine Aquakultur (GMA), Hafentörn 3, 25761, Büsum, Germany; Nofima AS, Sjølseng, NO-6600, Sunndalsøra, Norway
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8
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Salin K, Villasevil EM, Anderson GJ, Auer SK, Selman C, Hartley RC, Mullen W, Chinopoulos C, Metcalfe NB, Williams C. Decreased mitochondrial metabolic requirements in fasting animals carry an oxidative cost. Funct Ecol 2018; 32:2149-2157. [PMID: 30333678 PMCID: PMC6175143 DOI: 10.1111/1365-2435.13125] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 04/15/2018] [Indexed: 12/18/2022]
Abstract
Many animals experience periods of food shortage in their natural environment. It has been hypothesised that the metabolic responses of animals to naturally-occurring periods of food deprivation may have long-term negative impacts on their subsequent life-history.In particular, reductions in energy requirements in response to fasting may help preserve limited resources but potentially come at a cost of increased oxidative stress. However, little is known about this trade-off since studies of energy metabolism are generally conducted separately from those of oxidative stress.Using a novel approach that combines measurements of mitochondrial function with in vivo levels of hydrogen peroxide (H2O2) in brown trout (Salmo trutta), we show here that fasting induces energy savings in a highly metabolically active organ (the liver) but at the cost of a significant increase in H2O2, an important form of reactive oxygen species (ROS).After a 2-week period of fasting, brown trout reduced their whole-liver mitochondrial respiratory capacities (state 3, state 4 and cytochrome c oxidase activity), mainly due to reductions in liver size (and hence the total mitochondrial content). This was compensated for at the level of the mitochondrion, with an increase in state 3 respiration combined with a decrease in state 4 respiration, suggesting a selective increase in the capacity to produce ATP without a concomitant increase in energy dissipated through proton leakage. However, the reduction in total hepatic metabolic capacity in fasted fish was associated with an almost two-fold increase in in vivo mitochondrial H2O2 levels (as measured by the MitoB probe).The resulting increase in mitochondrial ROS, and hence potential risk of oxidative damage, provides mechanistic insight into the trade-off between the short-term energetic benefits of reducing metabolism in response to fasting and the potential long-term costs to subsequent life-history traits.
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Affiliation(s)
- Karine Salin
- Institute of Biodiversity, Animal Health and Comparative MedicineUniversity of GlasgowGlasgowUK
| | - Eugenia M. Villasevil
- Institute of Biodiversity, Animal Health and Comparative MedicineUniversity of GlasgowGlasgowUK
| | - Graeme J. Anderson
- Institute of Biodiversity, Animal Health and Comparative MedicineUniversity of GlasgowGlasgowUK
| | - Sonya K. Auer
- Institute of Biodiversity, Animal Health and Comparative MedicineUniversity of GlasgowGlasgowUK
| | - Colin Selman
- Institute of Biodiversity, Animal Health and Comparative MedicineUniversity of GlasgowGlasgowUK
| | | | - William Mullen
- Institute of Cardiovascular and Medical SciencesUniversity of GlasgowGlasgowUK
| | - Christos Chinopoulos
- Department of Medical BiochemistrySemmelweis UniversityBudapestHungary
- MTA‐SE Lendület Neurobiochemistry Research GroupBudapestHungary
| | - Neil B. Metcalfe
- Institute of Biodiversity, Animal Health and Comparative MedicineUniversity of GlasgowGlasgowUK
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9
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Wright PA, Turko AJ. Amphibious fishes: evolution and phenotypic plasticity. ACTA ACUST UNITED AC 2017; 219:2245-59. [PMID: 27489213 DOI: 10.1242/jeb.126649] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2016] [Accepted: 06/29/2016] [Indexed: 12/25/2022]
Abstract
Amphibious fishes spend part of their life in terrestrial habitats. The ability to tolerate life on land has evolved independently many times, with more than 200 extant species of amphibious fishes spanning 17 orders now reported. Many adaptations for life out of water have been described in the literature, and adaptive phenotypic plasticity may play an equally important role in promoting favourable matches between the terrestrial habitat and behavioural, physiological, biochemical and morphological characteristics. Amphibious fishes living at the interface of two very different environments must respond to issues relating to buoyancy/gravity, hydration/desiccation, low/high O2 availability, low/high CO2 accumulation and high/low NH3 solubility each time they traverse the air-water interface. Here, we review the literature for examples of plastic traits associated with the response to each of these challenges. Because there is evidence that phenotypic plasticity can facilitate the evolution of fixed traits in general, we summarize the types of investigations needed to more fully determine whether plasticity in extant amphibious fishes can provide indications of the strategies used during the evolution of terrestriality in tetrapods.
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Affiliation(s)
- Patricia A Wright
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
| | - Andy J Turko
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
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10
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Liang S, Li W, Zhang Y, Tang X, He J, Bai Y, Li D, Wang Y, Chen Q. Seasonal variation of metabolism in lizard Phrynocephalus vlangalii at high altitude. Comp Biochem Physiol A Mol Integr Physiol 2016; 203:341-347. [PMID: 27793615 DOI: 10.1016/j.cbpa.2016.10.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Revised: 10/04/2016] [Accepted: 10/21/2016] [Indexed: 11/16/2022]
Abstract
Seasonal acclimatization is important for animals to live optimally in the varying environment. Phrynocephalus vlangalii, a species of lizard endemic in China, distributes on Qinghai-Tibet Plateau ranging from 2000 to 4600m above sea level. To dissect how this lizard mediate metabolism to adapt various season, the preferred body temperature (Tb), standard metabolic rate (SMR), mitochondrial respiration rates and activities of four metabolic enzymes in this species were tested in different seasons (spring, summer, and autumn). The results showed that the preferred Tb was the lowest in spring and the highest in summer. SMR, maximal mitochondrial respiration rates in liver and skeletal muscle were the highest in spring. Similarly, higher activities of lactate dehydrogenase (LDH), citrate synthase (CS) and cytochrome c oxidase (CCO) activities of liver and skeletal muscle were observed in spring. However, β-hydroxyacyl coenzyme A dehydrogenase (HOAD) activities of liver and skeletal muscle were higher in autumn. On the whole, seasonal variation of metabolism is the highest in spring and the lowest in summer. Seasonal variation of metabolism is the opposite of preferred body temperature, this may be one of the mechanisms to adapt to the environment in P. vlangalii. Our results suggested that P. vlangalii at high altitude has certain adaptive characteristics on metabolism in different seasons.
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Affiliation(s)
- Shiwei Liang
- School of Life Sciences, Lanzhou University, 222 Tian Shui South Road, 730000 Lanzhou, China
| | - Weixin Li
- School of Life Sciences, Lanzhou University, 222 Tian Shui South Road, 730000 Lanzhou, China
| | - Yang Zhang
- School of Life Sciences, Lanzhou University, 222 Tian Shui South Road, 730000 Lanzhou, China
| | - Xiaolong Tang
- School of Life Sciences, Lanzhou University, 222 Tian Shui South Road, 730000 Lanzhou, China
| | - Jianzheng He
- School of Life Sciences, Lanzhou University, 222 Tian Shui South Road, 730000 Lanzhou, China
| | - Yucheng Bai
- School of Life Sciences, Lanzhou University, 222 Tian Shui South Road, 730000 Lanzhou, China
| | - Dongqin Li
- School of Life Sciences, Lanzhou University, 222 Tian Shui South Road, 730000 Lanzhou, China
| | - Yan Wang
- School of Life Sciences, Lanzhou University, 222 Tian Shui South Road, 730000 Lanzhou, China
| | - Qiang Chen
- School of Life Sciences, Lanzhou University, 222 Tian Shui South Road, 730000 Lanzhou, China.
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11
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Salin K, Villasevil EM, Auer SK, Anderson GJ, Selman C, Metcalfe NB, Chinopoulos C. Simultaneous measurement of mitochondrial respiration and ATP production in tissue homogenates and calculation of effective P/O ratios. Physiol Rep 2016; 4:e13007. [PMID: 27798358 PMCID: PMC5099967 DOI: 10.14814/phy2.13007] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 09/23/2016] [Indexed: 01/30/2023] Open
Abstract
The use of tissue homogenate has greatly aided the study of the functioning of mitochondria. However, the amount of ATP produced per oxygen molecule consumed, that is, the effective P/O ratio, has never been measured directly in tissue homogenate. Here we combine and refine existing methods previously used in permeabilized cells and isolated mitochondria to simultaneously measure mitochondrial ATP production (JATP) and oxygen consumption (JO2) in tissue homogenate. A major improvement over existing methods is in the control of ATPases that otherwise interfere with the ATP assay: our modified technique facilitates simultaneous measurement of the rates of "uncorrected" ATP synthesis and of ATP hydrolysis, thus minimizing the amount of tissue and time needed. Finally, we develop a novel method of calculating effective P/O ratios which corrects measurements of JATP and JO2 for rates of nonmitochondrial ATP hydrolysis and respiration, respectively. Measurements of JATP and JO2 in liver homogenates from brown trout (Salmo trutta) were highly reproducible, although activity declined once homogenates were 2 h old. We compared mitochondrial properties from fed and food-deprived animals to demonstrate that the method can detect mitochondrial flexibility in P/O ratios in response to nutritional state. This method simplifies studies examining the mitochondrial bioenergetics of tissue homogenates, obviating the need for differential centrifugation or chemical permeabilization and avoiding the use of nonmitochondrial ATPase inhibitors. We conclude that our approach for characterizing effective P/O ratio opens up new possibilities in the study of mitochondrial function in very small samples, where the use of other methods is limited.
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Affiliation(s)
- Karine Salin
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Eugenia M Villasevil
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Sonya K Auer
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Graeme J Anderson
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Colin Selman
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Neil B Metcalfe
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Christos Chinopoulos
- Department of Medical Biochemistry, Semmelweis University, Budapest, Hungary
- MTA-SE Lendület Neurobiochemistry Research Group, Budapest, Hungary
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12
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Global metabolite analysis of the land snail Theba pisana hemolymph during active and aestivated states. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY D-GENOMICS & PROTEOMICS 2016; 19:25-33. [PMID: 27318654 DOI: 10.1016/j.cbd.2016.05.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Revised: 05/18/2016] [Accepted: 05/25/2016] [Indexed: 12/14/2022]
Abstract
The state of metabolic dormancy has fascinated people for hundreds of years, leading to research exploring the identity of natural molecular components that may induce and maintain this state. Many animals lower their metabolism in response to high temperatures and/or arid conditions, a phenomenon called aestivation. The biological significance for this is clear; by strongly suppressing metabolic rate to low levels, animals minimize their exposure to stressful conditions. Understanding blood or hemolymph metabolite changes that occur between active and aestivated animals can provide valuable insights relating to those molecular components that regulate hypometabolism in animals, and how they afford adaptation to their different environmental conditions. In this study, we have investigated the hemolymph metabolite composition from the land snail Theba pisana, a remarkably resilient mollusc that displays an annual aestivation period. Using LC-MS-based metabolomics analysis, we have identified those hemolymph metabolites that show significant changes in relative abundance between active and aestivated states. We show that certain metabolites, including some phospholipids [e.g. LysoPC(14:0)], and amino acids such as l-arginine and l-tyrosine, are present at high levels within aestivated snails. Further investigation of our T. pisana RNA-sequencing data elucidated the entire repertoire of phospholipid-synthesis genes in the snail digestive gland, as a precursor towards future comparative investigation between the genetic components of aestivating and non-aestivating species. In summary, we have identified a large number of metabolites that are elevated in the hemolymph of aestivating snails, supporting their role in protecting against heat or desiccation.
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Abstract
Extended bouts of fasting are ingrained in the ecology of many organisms, characterizing aspects of reproduction, development, hibernation, estivation, migration, and infrequent feeding habits. The challenge of long fasting episodes is the need to maintain physiological homeostasis while relying solely on endogenous resources. To meet that challenge, animals utilize an integrated repertoire of behavioral, physiological, and biochemical responses that reduce metabolic rates, maintain tissue structure and function, and thus enhance survival. We have synthesized in this review the integrative physiological, morphological, and biochemical responses, and their stages, that characterize natural fasting bouts. Underlying the capacity to survive extended fasts are behaviors and mechanisms that reduce metabolic expenditure and shift the dependency to lipid utilization. Hormonal regulation and immune capacity are altered by fasting; hormones that trigger digestion, elevate metabolism, and support immune performance become depressed, whereas hormones that enhance the utilization of endogenous substrates are elevated. The negative energy budget that accompanies fasting leads to the loss of body mass as fat stores are depleted and tissues undergo atrophy (i.e., loss of mass). Absolute rates of body mass loss scale allometrically among vertebrates. Tissues and organs vary in the degree of atrophy and downregulation of function, depending on the degree to which they are used during the fast. Fasting affects the population dynamics and activities of the gut microbiota, an interplay that impacts the host's fasting biology. Fasting-induced gene expression programs underlie the broad spectrum of integrated physiological mechanisms responsible for an animal's ability to survive long episodes of natural fasting.
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Affiliation(s)
- Stephen M Secor
- Department of Biological Sciences, University of Alabama, Tuscaloosa, Alabama, USA
| | - Hannah V Carey
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin, Madison, Wisconsin, USA
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14
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Abstract
Many environmental conditions can constrain the ability of animals to obtain sufficient food energy, or transform that food energy into useful chemical forms. To survive extended periods under such conditions animals must suppress metabolic rate to conserve energy, water, or oxygen. Amongst small endotherms, this metabolic suppression is accompanied by and, in some cases, facilitated by a decrease in core body temperature-hibernation or daily torpor-though significant metabolic suppression can be achieved even with only modest cooling. Within some ectotherms, winter metabolic suppression exceeds the passive effects of cooling. During dry seasons, estivating ectotherms can reduce metabolism without changes in body temperature, conserving energy reserves, and reducing gas exchange and its inevitable loss of water vapor. This overview explores the similarities and differences of metabolic suppression among these states within adult animals (excluding developmental diapause), and integrates levels of organization from the whole animal to the genome, where possible. Several similarities among these states are highlighted, including patterns and regulation of metabolic balance, fuel use, and mitochondrial metabolism. Differences among models are also apparent, particularly in whether the metabolic suppression is intrinsic to the tissue or depends on the whole-animal response. While in these hypometabolic states, tissues from many animals are tolerant of hypoxia/anoxia, ischemia/reperfusion, and disuse. These natural models may, therefore, serve as valuable and instructive models for biomedical research.
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Affiliation(s)
- James F Staples
- Department of Biology, University of Western Ontario, London, Ontario, Canada
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15
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Urbina MA, Walsh PJ, Hill JV, Glover CN. Physiological and biochemical strategies for withstanding emersion in two galaxiid fishes. Comp Biochem Physiol A Mol Integr Physiol 2014; 176:49-58. [DOI: 10.1016/j.cbpa.2014.07.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Revised: 06/30/2014] [Accepted: 07/03/2014] [Indexed: 11/28/2022]
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16
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Zhao Y, Yang H, Storey KB, Chen M. RNA-seq dependent transcriptional analysis unveils gene expression profile in the intestine of sea cucumber Apostichopus japonicus during aestivation. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY D-GENOMICS & PROTEOMICS 2014; 10:30-43. [PMID: 24713300 DOI: 10.1016/j.cbd.2014.02.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Revised: 02/25/2014] [Accepted: 02/28/2014] [Indexed: 10/25/2022]
Abstract
The seasonal marine, the sea cucumber Apostichopus japonicus (Selenka, 1867), cycles annually between periods of torpor when water temperature is above about 25°C in summer and active life when temperature is below about 18°C. This species is a good candidate model organism for studies of environmentally-induced aestivation in marine invertebrates. Previous studies have examined various aspects of aestivation of A. japonicus, however, knowledge of the molecular regulation underpinning these events is still fragmentary. In the present study, we constructed a global gene expression profile of the intestine tissue of A. japonicus using RNA-seq to identify transcriptional responses associated with transitions between different states: non-aestivation (NA), deep-aestivation (DA), and arousal from aestivation (AA). The analysis identified 1245 differentially expressed genes (DEGs) between DA vs. NA states, 1338 DEGs between AA vs. DA, and 1321 DEGs between AA vs. NA using the criteria |Log2Ratio|≥1 and FDR≤0.001. Of these, 25 of the most significant DEGs were verified by real-time PCR, showing trends in expression patterns that were almost in full concordance between the two techniques. GO analysis revealed that for DA vs. NA, 24 metabolic associated processes were highly enriched (corrected p value<0.05) whereas for AA vs. NA, 12 transport and metabolism associated processes were significantly enriched (corrected p value<0.05). Pathways associated with aestivation were also mined, and indicated that most DEGs were enriched in metabolic and signal transduction pathways in the deep aestivation stage. Two up pathways were significantly enriched at the arousal stage (ribosome and metabolism of xenobiotics by cytochrome P450 pathway). A set of key DEGs was identified that may play vital roles in aestivation; these involved metabolism, detoxification and tissue protection, and energy-expensive processes. Our work presents an overview of dynamic gene expression in torpor-arousal cycles during aestivation of A. japonicus and identifies a series of candidate genes and pathways for further research on the molecular mechanisms of aestivation.
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Affiliation(s)
- Ye Zhao
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Hongsheng Yang
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PR China.
| | - Kenneth B Storey
- Institute of Biochemistry, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada
| | - Muyan Chen
- Fisheries College, Ocean University of China, Qingdao 266003, PR China.
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17
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da Silveira LC, do Nascimento LFR, Colquhoun A, Abe AS, de Souza SCR. Cardiac hypertrophy and structural and metabolic remodeling related to seasonal dormancy in the first annual cycle in tegu lizards. Comp Biochem Physiol A Mol Integr Physiol 2013; 165:371-80. [PMID: 23603066 DOI: 10.1016/j.cbpa.2013.04.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Revised: 04/09/2013] [Accepted: 04/11/2013] [Indexed: 11/16/2022]
Abstract
Morpho-functional adjustments in the heart of juvenile tegu lizards (Tupinambis merianae) were analyzed at distinct seasonal periods to investigate how the demands of growth and of energy saving are reconciled during the first annual cycle. The relative ventricular mass (Mv) was 31% and 69% larger in late autumn and winter dormancy, respectively, compared to early autumn. This effect did not persist during unfed arousal, suggesting that protein accumulates in the heart during hypometabolism and is degraded on arousal. Both the hypertrophy and the atrophy were disproportionate in the largest individuals. In contrast, Mv was smaller in lizards that were starved during spring activity compared to fed lizards, this effect being larger in smaller individuals. In late autumn and winter dormancy the spongy myocardium had 8% of the section area covered by lacunary spaces, which expanded after food intake during arousal and reached 29% in spring activity together with higher density of cardiomyocytes. Total and soluble proteins per mass unity were unchanged, and maximum activities of selected enzymes suggest sustained glycolytic and aerobic capacities during hypometabolism. Results indicate that important structural adjustments occur in the heart in anticipation of dormancy, and that the protein balance in the tissue is maintained at winter temperatures ~17°C.
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18
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Welker AF, Moreira DC, Campos ÉG, Hermes-Lima M. Role of redox metabolism for adaptation of aquatic animals to drastic changes in oxygen availability. Comp Biochem Physiol A Mol Integr Physiol 2013; 165:384-404. [PMID: 23587877 DOI: 10.1016/j.cbpa.2013.04.003] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Revised: 03/26/2013] [Accepted: 04/04/2013] [Indexed: 12/14/2022]
Abstract
Large changes in oxygen availability in aquatic environments, ranging from anoxia through to hyperoxia, can lead to corresponding wide variation in the production of reactive oxygen species (ROS) by animals with aquatic respiration. Therefore, animals living in marine, estuarine and freshwater environments have developed efficient antioxidant defenses to minimize oxidative stress and to regulate the cellular actions of ROS. Changes in oxygen levels may lead to bursts of ROS generation that can be particularly harmful. This situation is commonly experienced by aquatic animals during abrupt transitions from periods of hypoxia/anoxia back to oxygenated conditions (e.g. intertidal cycles). The strategies developed differ significantly among aquatic species and are (i) improvement of their endogenous antioxidant system under hyperoxia (that leads to increased ROS formation) or other similar ROS-related stresses, (ii) increase in antioxidant levels when displaying higher metabolic rates, (iii) presence of constitutively high levels of antioxidants, that attenuates oxidative stress derived from fluctuations in oxygen availability, or (iv) increase in the activity of antioxidant enzymes (and/or the levels of their mRNAs) during hypometabolic states associated with anoxia/hypoxia. This enhancement of the antioxidant system - coined over a decade ago as "preparation for oxidative stress" - controls the possible harmful effects of increased ROS formation during hypoxia/reoxygenation. The present article proposes a novel explanation for the biochemical and molecular mechanisms involved in this phenomenon that could be triggered by hypoxia-induced ROS formation. We also discuss the connections among oxygen sensing, oxidative damage and regulation of the endogenous antioxidant defense apparatus in animals adapted to many natural or man-made challenges of the aquatic environment.
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Affiliation(s)
- Alexis F Welker
- Laboratório de Radicais Livres, Departamento de Biologia Celular, Universidade de Brasília, Brasília, 70910-900 DF, Brazil
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Reilly BD, Hickey AJ, Cramp RL, Franklin CE. Decreased hydrogen peroxide production and mitochondrial respiration in skeletal muscle but not cardiac muscle of the green-striped burrowing frog, a natural model of muscle disuse. J Exp Biol 2013; 217:1087-93. [DOI: 10.1242/jeb.096834] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Summary
Suppression of disuse-induced muscle atrophy has been associated with altered mitochondrial reactive oxygen species (ROS) production in mammals. However, despite extended hindlimb immobility aestivating animals exhibit little skeletal muscle atrophy compared with artificially-immobilised mammalian models. Therefore, we studied mitochondrial respiration and ROS (H2O2) production in permeabilised muscle fibres of the green-striped burrowing frog, Cyclorana alboguttata. Mitochondrial respiration within saponin-permeabilised skeletal and cardiac muscle fibres was measured concurrently with ROS production using high-resolution respirometry coupled to custom-made fluorometers. After four months of aestivation, C. alboguttata had significantly depressed whole body metabolism by approximately 70% relative to control (active) frogs, and mitochondrial respiration in saponin-permeabilised skeletal muscle fibres decreased by almost 50% both in the absence of ADP and during oxidative phosphorylation. Mitochondrial ROS production showed up to an 88% depression in aestivating skeletal muscle when malate, succinate and pyruvate were present at concentrations likely reflecting those in vivo. The percentage ROS released per O2 molecule consumed was also approximately 94 % less at these concentrations indicating an intrinsic difference in ROS production capacities during aestivation. We also examined mitochondrial respiration and ROS production in permeabilised cardiac muscle fibres and found that aestivating frogs maintained respiratory flux and ROS production at control levels. These results show that aestivating C. alboguttata has the capacity to independently regulate mitochondrial function in skeletal and cardiac muscles. Furthermore, this work indicates that ROS production can be suppressed in the disused skeletal muscle of aestivating frogs, which may in turn protect against potential oxidative damage and preserve skeletal muscle structure during aestivation and following arousal.
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20
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Groom DJE, Kuchel L, Richards JG. Metabolic responses of the South American ornate horned frog (Ceratophrys ornata) to estivation. Comp Biochem Physiol B Biochem Mol Biol 2012; 164:2-9. [PMID: 22902863 DOI: 10.1016/j.cbpb.2012.08.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2011] [Revised: 08/01/2012] [Accepted: 08/01/2012] [Indexed: 01/15/2023]
Abstract
We examined the metabolic responses of the South American frog, Ceratophrys ornata, to laboratory-induced estivation. Whole-animal and mass-specific oxygen consumption rates (VO(2)) did not change during fasting or 56days of estivation, despite observing significant decreases in body mass. The maintenance of mass-specific metabolic rate at routine levels during estivation suggests that metabolic rate suppression is not a major response to estivation in this species. There was a significant decline in liver glycogen and a loss of adipose tissue mass during estivation, suggesting that both carbohydrate and lipid pathways are used to fuel metabolism during estivation. The activity of pyruvate dehydrogenase, an important regulator of carbohydrate oxidation, and carnitine palmitoyltransferase and 3-hydroxyacyl-CoA dehydrogenase, regulators of lipid oxidation, showed no significant change in activity in liver, heart, and muscle between estivating and active frogs. There was an increase in plasma osmolality, which is characteristic of estivating animals. Overall, our metabolic analysis of estivation in C. ornata indicates that this species does not employ a dramatic suppression metabolic rate to survive dehydration stress and that both endogenous carbohydrates and lipids are used as metabolic fuels.
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Affiliation(s)
- Derrick J E Groom
- Department of Zoology, The University of British Columbia, Vancouver, British Columbia, Canada
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21
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Frick NT, Bystriansky JS, Ip YK, Chew SF, Ballantyne JS. Cytochrome c oxidase is regulated by modulations in protein expression and mitochondrial membrane phospholipid composition in estivating African lungfish. Am J Physiol Regul Integr Comp Physiol 2010; 298:R608-16. [DOI: 10.1152/ajpregu.90815.2008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We examined some of the potential mechanisms lungfish ( Protopterus dolloi ) use to regulate cytochrome c oxidase (CCO), during metabolic depression. CCO activity was reduced by 67% in isolated liver mitochondria of estivating fish. This was likely accomplished, in part, by the 46% reduction in CCO subunit I protein expression in the liver. No change in the mRNA expression levels of CCO subunits I, II, III, and IV were found in the liver, suggesting CCO is under translational regulation; however, in the kidney, messenger limitation may be a factor as the expression of subunits I and II were depressed (∼10-fold) during estivation, suggesting tissue-specific mechanisms of regulation. CCO is influenced by mitochondrial membrane phospholipids, particularly cardiolipin (CL). In P. dolloi , the phospholipid composition of the liver mitochondrial membrane changed during estivation, with a ∼2.3-fold reduction in the amount of CL. Significant positive correlations were found between CCO activity and the amount of CL and phosphatidylethanolamine within the mitochondrial membrane. It appears CCO activity is regulated through multiple mechanisms in P. dolloi , and individual subunits of CCO are regulated independently, and in a tissue-specific manner. It is proposed that altering the amount of CL within the mitochondrial membrane may be a means of regulating CCO activity during metabolical depression in the African lungfish, P. dolloi .
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Affiliation(s)
- N. T. Frick
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
| | - J. S. Bystriansky
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
| | - Y. K. Ip
- Department of Biological Sciences, National University of Singapore, Singapore, Republic of Singapore; and
| | - S. F. Chew
- Natural Sciences, National Institute of Education, Nanyang Technological University, Singapore, Republic of Singapore
| | - J. S. Ballantyne
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
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McCue MD. Starvation physiology: reviewing the different strategies animals use to survive a common challenge. Comp Biochem Physiol A Mol Integr Physiol 2010; 156:1-18. [PMID: 20060056 DOI: 10.1016/j.cbpa.2010.01.002] [Citation(s) in RCA: 418] [Impact Index Per Article: 29.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2009] [Revised: 12/30/2009] [Accepted: 01/03/2010] [Indexed: 11/26/2022]
Abstract
All animals face the possibility of limitations in food resources that could ultimately lead to starvation-induced mortality. The primary goal of this review is to characterize the various physiological strategies that allow different animals to survive starvation. The ancillary goals of this work are to identify areas in which investigations of starvation can be improved and to discuss recent advances and emerging directions in starvation research. The ubiquity of food limitation among animals, inconsistent terminology associated with starvation and fasting, and rationale for scientific investigations into starvation are discussed. Similarities and differences with regard to carbohydrate, lipid, and protein metabolism during starvation are also examined in a comparative context. Examples from the literature are used to underscore areas in which reporting and statistical practices, particularly those involved with starvation-induced changes in body composition and starvation-induced hypometabolism can be improved. The review concludes by highlighting several recent advances and promising research directions in starvation physiology. Because the hundreds of studies reviewed here vary so widely in their experimental designs and treatments, formal comparisons of starvation responses among studies and taxa are generally precluded; nevertheless, it is my aim to provide a starting point from which we may develop novel approaches, tools, and hypotheses to facilitate meaningful investigations into the physiology of starvation in animals.
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Affiliation(s)
- Marshall D McCue
- Mitrani Department of Desert Ecology, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion, Israel.
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24
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Richards JG. Metabolic Rate Suppression as a Mechanism for Surviving Environmental Challenge in Fish. AESTIVATION 2010; 49:113-39. [DOI: 10.1007/978-3-642-02421-4_6] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Upregulation of intracellular antioxidant enzymes in brain and heart during estivation in the African lungfish Protopterus dolloi. J Comp Physiol B 2009; 180:361-9. [DOI: 10.1007/s00360-009-0416-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2009] [Revised: 10/08/2009] [Accepted: 10/13/2009] [Indexed: 12/28/2022]
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The unusual energy metabolism of elasmobranch fishes. Comp Biochem Physiol A Mol Integr Physiol 2009; 155:417-34. [PMID: 19822221 DOI: 10.1016/j.cbpa.2009.09.031] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2009] [Revised: 09/28/2009] [Accepted: 09/29/2009] [Indexed: 11/17/2022]
Abstract
The unusual energy metabolism of elasmobranchs is characterized by limited or absent fatty acid oxidation in cardiac and skeletal muscle and a great reliance on ketone bodies and amino acids as oxidative fuels in these tissues. Other extrahepatic tissues in elasmobranchs rely on ketone bodies and amino acids for aerobic energy production but, unlike muscle, also appear to possess a significant capacity to oxidize fatty acids. This organization of energy metabolism is reflected by relatively low plasma levels of non-esterified fatty acids (NEFA) and by plasma levels of the ketone body ss-hydroxybutyrate that are as high as those seen in fasted mammals. The preference for ketone body oxidation rather than fatty acid oxidation in muscle of elasmobranchs under routine conditions is opposite to the situation in teleosts and mammals. Carbohydrates appear to be utilized as a fuel source in elasmobranchs, similar to other vertebrates. Amino acid- and lipid-fueled ketogenesis in the liver, the lipid storage site in elasmobranchs, sustains the demand for ketone bodies as oxidative fuels. The liver also appears to export NEFA and serves a buoyancy role. The regulation of energy metabolism in elasmobranchs and the effects of environmental factors remain poorly understood. The metabolic organization of elasmobranchs was likely present in the common ancestor of the Chondrichthyes ca. 400million years ago and, speculatively, it may reflect the ancestral metabolism of jawed vertebrates. We assess hypotheses for the evolution of the unusual energy metabolism of elasmobranchs and propose that the need to synthesize urea has influenced the utilization of ketone bodies and amino acids as oxidative fuels.
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Frick NT, Bystriansky JS, Ip YK, Chew SF, Ballantyne JS. Carbohydrate and amino acid metabolism in fasting and aestivating African lungfish (Protopterus dolloi). Comp Biochem Physiol A Mol Integr Physiol 2008; 151:85-92. [DOI: 10.1016/j.cbpa.2008.06.003] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2008] [Revised: 06/03/2008] [Accepted: 06/04/2008] [Indexed: 12/01/2022]
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