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Coulson SZ, Duffy BM, Staples JF. Mitochondrial techniques for physiologists. Comp Biochem Physiol B Biochem Mol Biol 2024; 271:110947. [PMID: 38278207 DOI: 10.1016/j.cbpb.2024.110947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 01/22/2024] [Accepted: 01/23/2024] [Indexed: 01/28/2024]
Abstract
Mitochondria serve several important roles in maintaining cellular homeostasis, including adenosine triphosphate (ATP) synthesis, apoptotic signalling, and regulation of both reactive oxygen species (ROS) and calcium. Therefore, mitochondrial studies may reveal insights into metabolism at higher levels of physiological organization. The apparent complexity of mitochondrial function may be daunting to researchers new to mitochondrial physiology. This review is aimed, therefore, at such researchers to provide a brief, yet approachable overview of common techniques used to assess mitochondrial function. Here we discuss the use of high-resolution respirometry in mitochondrial experiments and common analytical platforms used for this technique. Next, we compare the use of common mitochondrial preparation techniques, including adherent cells, tissue homogenate, permeabilized fibers and isolated mitochondria. Finally, we outline additional techniques that can be used in tandem with high-resolution respirometry to assess additional aspects of mitochondrial metabolism, including ATP synthesis, calcium uptake, membrane potential and reactive oxygen species emission. We also include limitations to each of these techniques and outline recommendations for experimental design and interpretation. With a general understanding of methodologies commonly used to study mitochondrial physiology, experimenters may begin contributing to our understanding of this organelle, and how it affects other physiological phenotypes.
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Affiliation(s)
- Soren Z Coulson
- Department of Biology, University of Western Ontario, 1151 Richmond Street, London, Ontario, Canada.
| | - Brynne M Duffy
- Department of Biology, University of Western Ontario, 1151 Richmond Street, London, Ontario, Canada. https://twitter.com/BrynneDuffy
| | - James F Staples
- Department of Biology, University of Western Ontario, 1151 Richmond Street, London, Ontario, Canada
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2
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Thoral E, Dargère L, Medina-Suárez I, Clair A, Averty L, Sigaud J, Morales A, Salin K, Teulier L. Non-lethal sampling for assessment of mitochondrial function does not affect metabolic rate and swimming performance. Philos Trans R Soc Lond B Biol Sci 2024; 379:20220483. [PMID: 38186271 PMCID: PMC10772603 DOI: 10.1098/rstb.2022.0483] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Accepted: 09/26/2023] [Indexed: 01/09/2024] Open
Abstract
A fundamental issue in the metabolic field is whether it is possible to understand underlying mechanisms that characterize individual variation. Whole-animal performance relies on mitochondrial function as it produces energy for cellular processes. However, our lack of longitudinal measures to evaluate how mitochondrial function can change within and among individuals and with environmental context makes it difficult to assess individual variation in mitochondrial traits. The aims of this study were to test the repeatability of muscle mitochondrial metabolism by performing two biopsies of red muscle, and to evaluate the effects of biopsies on whole-animal performance in goldfish Carassius auratus. Our results show that basal mitochondrial respiration and net phosphorylation efficiency are repeatable at 14-day intervals. We also show that swimming performance (optimal cost of transport and critical swimming speed) was repeatable in biopsied fish, whereas the repeatability of individual oxygen consumption (standard and maximal metabolic rates) seemed unstable over time. However, we noted that the means of individual and mitochondrial traits did not change over time in biopsied fish. This study shows that muscle biopsies allow the measurement of mitochondrial metabolism without sacrificing animals and that two muscle biopsies 14 days apart affect the intraspecific variation in fish performance without affecting average performance of individuals. This article is part of the theme issue 'The evolutionary significance of variation in metabolic rates'.
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Affiliation(s)
- Elisa Thoral
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, ENTPE, UMR 5023 LEHNA, F-69622, Villeurbanne, France
- Department of Biology, Section for Evolutionary Ecology, Lund University, Sölvegatan 37, Lund 223 62, Sweden
| | - Lauréliane Dargère
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, ENTPE, UMR 5023 LEHNA, F-69622, Villeurbanne, France
| | - Ione Medina-Suárez
- Instituto de Oceanografía y Cambio Global, IOCAG, Universidad de Las Palmas de Gran Canaria, Unidad Asociada ULPGC-CSIC, Campus de Taliarte, 35214 Telde, Gran Canaria, Canary Islands, Spain
| | - Angéline Clair
- Plateforme Animalerie Conventionnelle et Sauvage Expérimentale de la Doua (ACSED), Fédération de Recherche 3728, Univ Lyon, Université Claude Bernard Lyon 1, CNRS, ENS-Lyon, INRAE, INSA, VetAgroSup 69622, Villeurbanne, France
| | - Laetitia Averty
- Plateforme Animalerie Conventionnelle et Sauvage Expérimentale de la Doua (ACSED), Fédération de Recherche 3728, Univ Lyon, Université Claude Bernard Lyon 1, CNRS, ENS-Lyon, INRAE, INSA, VetAgroSup 69622, Villeurbanne, France
| | - Justine Sigaud
- Plateforme Animalerie Conventionnelle et Sauvage Expérimentale de la Doua (ACSED), Fédération de Recherche 3728, Univ Lyon, Université Claude Bernard Lyon 1, CNRS, ENS-Lyon, INRAE, INSA, VetAgroSup 69622, Villeurbanne, France
| | - Anne Morales
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, ENTPE, UMR 5023 LEHNA, F-69622, Villeurbanne, France
| | - Karine Salin
- Ifremer, CNRS, RD, Laboratory of Environmental Marine Sciences, Université de Brest, 29280 Plouzané, France
| | - Loïc Teulier
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, ENTPE, UMR 5023 LEHNA, F-69622, Villeurbanne, France
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3
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Dressler TL, Han Lee V, Klose K, Eliason EJ. Thermal tolerance and vulnerability to warming differ between populations of wild Oncorhynchus mykiss near the species' southern range limit. Sci Rep 2023; 13:14538. [PMID: 37666931 PMCID: PMC10477306 DOI: 10.1038/s41598-023-41173-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 08/23/2023] [Indexed: 09/06/2023] Open
Abstract
Fish habitat temperatures are increasing due to human impacts including climate change. For broadly distributed species, thermal tolerance can vary at the population level, making it challenging to predict which populations are most vulnerable to warming. Populations inhabiting warm range boundaries may be more resilient to these changes due to adaptation or acclimatization to warmer temperatures, or they may be more vulnerable as temperatures may already approach their physiological limits. We tested functional and critical thermal tolerance of two populations of wild Oncorhynchus mykiss near the species' southern range limit and, as predicted, found population-specific responses to temperature. Specifically, the population inhabiting the warmer stream, Piru Creek, had higher critical thermal maxima and higher functional thermal tolerance compared to the population from the cooler stream, Arroyo Seco. Arroyo Seco O. mykiss are more likely to experience a limitation of aerobic scope with warming. Piru Creek O. mykiss, however, had higher resting metabolic rates and prolonged exercise recovery, meaning that they could be more vulnerable to warming if prey or dissolved oxygen become limited. Temperature varies widely between streams near the O. mykiss southern range limit and populations will likely have unique responses to warming based on their thermal tolerances and metabolic requirements.
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Affiliation(s)
- T L Dressler
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA, 93106, USA
| | - V Han Lee
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA, 93106, USA
| | - K Klose
- U.S. Forest Service, Los Padres National Forest, 1980 Old Mission Drive, Solvang, CA, 93463, USA
| | - E J Eliason
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA, 93106, USA.
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4
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Bowering LR, McArley TJ, Devaux JBL, Hickey AJR, Herbert NA. Metabolic resilience of the Australasian snapper ( Chrysophrys auratus) to marine heatwaves and hypoxia. Front Physiol 2023; 14:1215442. [PMID: 37528894 PMCID: PMC10387550 DOI: 10.3389/fphys.2023.1215442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Accepted: 07/05/2023] [Indexed: 08/03/2023] Open
Abstract
Marine organisms are under threat from a simultaneous combination of climate change stressors, including warming sea surface temperatures (SST), marine heatwave (MHW) episodes, and hypoxic events. This study sought to investigate the impacts of these stressors on the Australasian snapper (C. auratus) - a finfish species of high commercial and recreational importance, from the largest snapper fishery in Aotearoa New Zealand (SNA1). A MHW scenario was simulated from 21°C (current February SST average for north-eastern New Zealand) to a future predicted level of 25°C, with the whole-animal and mitochondrial metabolic performance of snapper in response to hypoxia and elevated temperature tested after 1-, 10-, and 30-days of thermal challenge. It was hypothesised that key indicators of snapper metabolic performance would decline after 1-day of MHW stress, but that partial recovery might arise as result of thermal plasticity after chronic (e.g., 30-day) exposures. In contrast to this hypothesis, snapper performance remained high throughout the MHW: 1) Aerobic metabolic scope increased after 1-day of 25°C exposure and remained high. 2) Hypoxia tolerance, measured as the critical O2 pressure and O2 pressure where loss of equilibrium occurred, declined after 1-day of warm-acclimation, but recovered quickly with no observable difference from the 21°C control following 30-days at 25°C. 3) The performance of snapper mitochondria was also maintained, with oxidative phosphorylation respiration and proton leak flux across the inner mitochondrial membrane of the heart remaining mostly unaffected. Collectively, the results suggest that heart mitochondria displayed resilience, or plasticity, in snapper chronically exposed to 25°C. Therefore, contrary to the notion of climate change having adverse metabolic effects, future temperatures approaching 25°C may be tolerated by C. auratus in Northern New Zealand. Even in conjunction with supplementary hypoxia, 25°C appears to represent a metabolically optimal temperature for this species.
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Affiliation(s)
- Lyvia R. Bowering
- Institute of Marine Science, University of Auckland, Leigh, New Zealand
| | | | - Jules B. L. Devaux
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | | | - Neill A. Herbert
- Institute of Marine Science, University of Auckland, Leigh, New Zealand
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5
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Healy TM, Burton RS. Loss of mitochondrial performance at high temperatures is correlated with upper thermal tolerance among populations of an intertidal copepod. Comp Biochem Physiol B Biochem Mol Biol 2023; 266:110836. [PMID: 36801253 DOI: 10.1016/j.cbpb.2023.110836] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 01/24/2023] [Accepted: 02/13/2023] [Indexed: 02/17/2023]
Abstract
Environmental temperatures have pervasive effects on the performance and tolerance of ectothermic organisms, and thermal tolerance limits likely play key roles underlying biogeographic ranges and responses to environmental change. Mitochondria are central to metabolic processes in eukaryotic cells, and these metabolic functions are thermally sensitive; however, potential relationships between mitochondrial function, thermal tolerance limits and local thermal adaptation in general remain unresolved. Loss of ATP synthesis capacity at high temperatures has recently been suggested as a mechanistic link between mitochondrial function and upper thermal tolerance limits. Here we use a common-garden experiment with seven locally adapted populations of intertidal copepods (Tigriopus californicus), spanning approximately 21.5° latitude, to assess genetically based variation in the thermal performance curves of maximal ATP synthesis rates in isolated mitochondria. These thermal performance curves displayed substantial variation among populations with higher ATP synthesis rates at lower temperatures (20-25 °C) in northern populations than in southern populations. In contrast, mitochondria from southern populations maintained ATP synthesis rates at higher temperatures than the temperatures that caused loss of ATP synthesis capacity in mitochondria from northern populations. Additionally, there was a tight correlation between the thermal limits of ATP synthesis and previously determined variation in upper thermal tolerance limits among populations. This suggests that mitochondria may play an important role in latitudinal thermal adaptation in T. californicus, and supports the hypothesis that loss of mitochondrial performance at high temperatures is linked to whole-organism thermal tolerance limits in this ectotherm.
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Affiliation(s)
- Timothy M Healy
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive #0202, La Jolla, CA, USA.
| | - Ronald S Burton
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive #0202, La Jolla, CA, USA
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6
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Rees BB, Reemeyer JE, Irving BA. Interindividual variation in maximum aerobic metabolism varies with gill morphology and myocardial bioenergetics. J Exp Biol 2022; 225:275636. [DOI: 10.1242/jeb.243680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 05/27/2022] [Indexed: 11/20/2022]
Abstract
This study asked whether interindividual variation in maximum and standard aerobic metabolic rates of the Gulf killifish, Fundulus grandis, correlate with gill morphology and cardiac mitochondrial bioenergetics, traits reflecting critical steps in the O2 transport cascade from the environment to the tissues. Maximum metabolic rate (MMR) was positively related to body mass, total gill filament length, and myocardial oxygen consumption during maximum oxidative phosphorylation (multiple R2=0.836). Standard metabolic rate (SMR) was positively related to body mass, total gill filament length, and myocardial oxygen consumption during maximum electron transport system activity (multiple R2=0.717). After controlling for body mass, individuals with longer gill filaments, summed over all gill arches, or greater cardiac respiratory capacity had higher whole-animal metabolic rates. The overall model fit and the explanatory power of individual predictor variables were better for MMR than for SMR, suggesting that gill morphology and myocardial bioenergetics are more important in determining active rather than resting metabolism. After accounting for body mass, heart ventricle mass was not related to variation in MMR or SMR, indicating that the quality of the heart (i.e., the capacity for mitochondrial metabolism) was more influential than heart size. Finally, the myocardial oxygen consumption required to offset the dissipation of the transmembrane proton gradient in the absence of ATP synthesis was not correlated with either MMR or SMR. The results support the idea that interindividual variation in aerobic metabolism, particularly maximum metabolic rate, is associated with variation in specific steps in the O2 transport cascade.
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Affiliation(s)
- Bernard B. Rees
- 1 Department of Biological Sciences, University of New Orleans, New Orleans, LA 70148, USA
| | - Jessica E. Reemeyer
- 2 Department of Biology, McGill University, Montreal, Quebec H3A 1B1, Canada
| | - Brian A. Irving
- 3 School of Kinesiology, Louisiana State University, Baton Rouge, LA 70803, USA
- 4 Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, LA 70808, USA
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7
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Dawson NJ, Scott GR. Adaptive increases in respiratory capacity and O 2 affinity of subsarcolemmal mitochondria from skeletal muscle of high-altitude deer mice. FASEB J 2022; 36:e22391. [PMID: 35661419 DOI: 10.1096/fj.202200219r] [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: 02/28/2022] [Revised: 05/05/2022] [Accepted: 05/23/2022] [Indexed: 11/11/2022]
Abstract
Aerobic energy demands have led to the evolution of complex mitochondrial reticula in highly oxidative muscles, but the extent to which metabolic challenges can be met with adaptive changes in physiology of specific mitochondrial fractions remains unresolved. We examined mitochondrial mechanisms supporting adaptive increases in aerobic performance in deer mice (Peromyscus maniculatus) adapted to the hypoxic environment at high altitude. High-altitude and low-altitude mice were born and raised in captivity, and exposed as adults to normoxia or hypobaric hypoxia (12 kPa O2 for 6-8 weeks). Subsarcolemmal and intermyofibrillar mitochondria were isolated from the gastrocnemius, and a comprehensive substrate titration protocol was used to examine mitochondrial physiology and O2 kinetics by high-resolution respirometry and fluorometry. High-altitude mice had greater yield, respiratory capacity for oxidative phosphorylation, and O2 affinity (lower P50 ) of subsarcolemmal mitochondria compared to low-altitude mice across environments, but there were no species difference in these traits in intermyofibrillar mitochondria. High-altitude mice also had greater capacities of complex II relative to complexes I + II and higher succinate dehydrogenase activities in both mitochondrial fractions. Exposure to chronic hypoxia reduced reactive oxygen species (ROS) emission in high-altitude mice but not in low-altitude mice. Our findings suggest that functional changes in subsarcolemmal mitochondria contribute to improving aerobic performance in hypoxia in high-altitude deer mice. Therefore, physiological variation in specific mitochondrial fractions can help overcome the metabolic challenges of life at high altitude.
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Affiliation(s)
- Neal J Dawson
- Department of Biology, McMaster University, Hamilton, Ontario, Canada.,Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Graham R Scott
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
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8
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Lamptey DI, Sparks RW, De Oca RM, Skolik R, Menze MA, Martinez E. Seasonal changes in mitochondrial bioenergetics and physiological performance of the bluegill sunfish, Lepomis macrochirus, from a shallow, Midwest river. J Therm Biol 2022; 104:103186. [DOI: 10.1016/j.jtherbio.2021.103186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 12/24/2021] [Accepted: 12/31/2021] [Indexed: 11/16/2022]
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9
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Breton S, Ghiselli F, Milani L. Mitochondrial Short-Term Plastic Responses and Long-Term Evolutionary Dynamics in Animal Species. Genome Biol Evol 2021; 13:6248094. [PMID: 33892508 PMCID: PMC8290114 DOI: 10.1093/gbe/evab084] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 04/13/2021] [Accepted: 04/20/2021] [Indexed: 12/15/2022] Open
Abstract
How do species respond or adapt to environmental changes? The answer to this depends partly on mitochondrial epigenetics and genetics, new players in promoting adaptation to both short- and long-term environmental changes. In this review, we explore how mitochondrial epigenetics and genetics mechanisms, such as mtDNA methylation, mtDNA-derived noncoding RNAs, micropeptides, mtDNA mutations, and adaptations, can contribute to animal plasticity and adaptation. We also briefly discuss the challenges in assessing mtDNA adaptive evolution. In sum, this review covers new advances in the field of mitochondrial genomics, many of which are still controversial, and discusses processes still somewhat obscure, and some of which are still quite speculative and require further robust experimentation.
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Affiliation(s)
- Sophie Breton
- Department of Biological Sciences, University of Montreal, Quebec, Canada
| | - Fabrizio Ghiselli
- Department of Biological, Geological, and Environmental Sciences, University of Bologna, Italy
| | - Liliana Milani
- Department of Biological, Geological, and Environmental Sciences, University of Bologna, Italy
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10
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Abstract
Temperature is a critical abiotic factor shaping the distribution and abundance of species, but the mechanisms that underpin organismal thermal limits remain poorly understood. One possible mechanism underlying these limits is the failure of mitochondrial processes, as mitochondria play a crucial role in animals as the primary site of ATP production. Conventional measures of mitochondrial performance suggest that these organelles can function at temperatures much higher than those that limit whole-organism function, suggesting that they are unlikely to set organismal thermal limits. However, this conclusion is challenged by recent data connecting sequence variation in mitochondrial genes to whole-organism thermal tolerance. Here, we review the current state of knowledge of mitochondrial responses to thermal extremes and ask whether they are consistent with a role for mitochondrial function in shaping whole-organism thermal limits. The available data are fragmentary, but it is possible to draw some conclusions. There is little evidence that failure of maximal mitochondrial oxidative capacity as assessed in vitro sets thermal limits, but there is some evidence to suggest that temperature effects on ATP synthetic capacity may be important. Several studies suggest that loss of mitochondrial coupling is associated with the thermal limits for organismal growth, although this needs to be rigorously tested. Most studies have utilized isolated mitochondrial preparations to assess the effects of temperature on these organelles, and there remain many untapped opportunities to address these questions using preparations that retain more of their biological context to better connect these subcellular processes with whole-organism thermal limits.
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Affiliation(s)
- Dillon J Chung
- National Heart Lung and Blood Institute, National Institutes of Health, 10 Center Drive, Bethesda, MD 20814, USA
| | - Patricia M Schulte
- Department of Zoology, University of British Columbia, 6270 University Blvd, Vancouver, British Columbia, Canada V6T 1Z4
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Larsen FJ, Schiffer TA, Zinner C, Willis SJ, Morales‐Alamo D, Calbet JA, Boushel R, Holmberg H. Mitochondrial oxygen affinity increases after sprint interval training and is related to the improvement in peak oxygen uptake. Acta Physiol (Oxf) 2020; 229:e13463. [PMID: 32144872 DOI: 10.1111/apha.13463] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 02/28/2020] [Accepted: 03/02/2020] [Indexed: 01/16/2023]
Abstract
AIMS The body responds to exercise training by profound adaptations throughout the cardiorespiratory and muscular systems, which may result in improvements in maximal oxygen consumption (VO2 peak) and mitochondrial capacity. By convenience, mitochondrial respiration is often measured at supra-physiological oxygen levels, an approach that ignores any potential regulatory role of mitochondrial affinity for oxygen (p50mito ) at physiological oxygen levels. METHODS In this study, we examined the p50mito of mitochondria isolated from the Vastus lateralis and Triceps brachii in 12 healthy volunteers before and after a training intervention with seven sessions of sprint interval training using both leg cycling and arm cranking. The changes in p50mito were compared to changes in whole-body VO2 peak. RESULTS We here show that p50mito is similar in isolated mitochondria from the Vastus (40 ± 3.8 Pa) compared to Triceps (39 ± 3.3) but decreases (mitochondrial oxygen affinity increases) after seven sessions of sprint interval training (to 26 ± 2.2 Pa in Vastus and 22 ± 2.7 Pa in Triceps, both P < .01). The change in VO2 peak modelled from changes in p50mito was correlated to actual measured changes in VO2 peak (R2 = .41, P = .002). CONCLUSION Together with mitochondrial respiratory capacity, p50mito is a critical factor when measuring mitochondrial function, it can decrease with sprint interval training and should be considered in the integrative analysis of the oxygen cascade from lung to mitochondria.
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Affiliation(s)
- Filip J. Larsen
- Åstrand Laboratory The Swedish School of Sport and Health Sciences Stockholm Sweden
| | - Tomas A. Schiffer
- Department of Physiology and Pharmacology Karolinska Institutet Stockholm Sweden
| | - Christoph Zinner
- Department of Sport University of Applied Sciences for Police and Administration of Hesse Wiesbaden Germany
| | - Sarah J. Willis
- Institute of Sport Sciences University of Lausanne Lausanne Switzerland
| | - David Morales‐Alamo
- Department of Physical Education and Research Institute of Biomedical and Health Sciences (IUIBS) University of Las Palmas de Gran Canaria Gran Canaria Spain
| | - Jose A.L. Calbet
- Department of Physical Education and Research Institute of Biomedical and Health Sciences (IUIBS) University of Las Palmas de Gran Canaria Gran Canaria Spain
- School of Kinesiology Faculty of Education The University of British Columbia Vancouver BC Canada
- Department of Physical Performance The Norwegian School of Sport Sciences Oslo Norway
| | - Robert Boushel
- School of Kinesiology Faculty of Education The University of British Columbia Vancouver BC Canada
| | - Hans‐Christer Holmberg
- Swedish Winter Sports Research Centre Department of Health SciencesMid Sweden University Östersund Sweden
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12
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Crawford DL, Schulte PM, Whitehead A, Oleksiak MF. Evolutionary Physiology and Genomics in the Highly Adaptable Killifish (
Fundulus heteroclitus
). Compr Physiol 2020; 10:637-671. [DOI: 10.1002/cphy.c190004] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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13
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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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14
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Milani L, Ghiselli F. Faraway, so close. The comparative method and the potential of non-model animals in mitochondrial research. Philos Trans R Soc Lond B Biol Sci 2019; 375:20190186. [PMID: 31787048 DOI: 10.1098/rstb.2019.0186] [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] [Indexed: 02/07/2023] Open
Abstract
Inference from model organisms has been the engine for many discoveries in life science, but indiscriminate generalization leads to oversimplifications and misconceptions. Model organisms and inductive reasoning are irreplaceable: there is no other way to tackle the complexity of living systems. At the same time, it is not advisable to infer general patterns from a restricted number of species, which are very far from being representative of the diversity of life. Not all models are equal. Some organisms are suitable to find similarities across species, other highly specialized organisms can be used to focus on differences. In this opinion piece, we discuss the dominance of the mechanistic/reductionist approach in life sciences and make a case for an enhanced application of the comparative approach to study processes in all their various forms across different organisms. We also enlist some rising animal models in mitochondrial research, to exemplify how non-model organisms can be chosen in a comparative framework. These taxa often do not possess implemented tools and dedicated methods/resources. However, because of specific features, they have the potential to address still unanswered biological questions. Finally, we discuss future perspectives and caveats of the comparative method in the age of 'big data'. This article is part of the theme issue 'Linking the mitochondrial genotype to phenotype: a complex endeavour'.
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Affiliation(s)
- Liliana Milani
- Department of Biological, Geological, and Environmental Sciences, University of Bologna, Bologna, Italy
| | - Fabrizio Ghiselli
- Department of Biological, Geological, and Environmental Sciences, University of Bologna, Bologna, Italy
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15
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Healy TM, Bock AK, Burton RS. Variation in developmental temperature alters adulthood plasticity of thermal tolerance in Tigriopus californicus. ACTA ACUST UNITED AC 2019; 222:jeb.213405. [PMID: 31597734 DOI: 10.1242/jeb.213405] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 10/02/2019] [Indexed: 12/11/2022]
Abstract
In response to environmental change, organisms rely on both genetic adaptation and phenotypic plasticity to adjust key traits that are necessary for survival and reproduction. Given the accelerating rate of climate change, plasticity may be particularly important. For organisms in warming aquatic habitats, upper thermal tolerance is likely to be a key trait, and many organisms express plasticity in this trait in response to developmental or adulthood temperatures. Although plasticity at one life stage may influence plasticity at another life stage, relatively little is known about this possibility for thermal tolerance. Here, we used locally adapted populations of the copepod Tigriopus californicus to investigate these potential effects in an intertidal ectotherm. We found that low latitude populations had greater critical thermal maxima (CTmax) than high latitude populations, and variation in developmental temperature altered CTmax plasticity in adults. After development at 25°C, CTmax was plastic in adults, whereas no adulthood plasticity in this trait was observed after development at 20°C. This pattern was identical across four populations, suggesting that local thermal adaptation has not shaped this effect among these populations. Differences in the capacities to maintain ATP synthesis rates and to induce heat shock proteins at high temperatures, two likely mechanisms of local adaptation in this species, were consistent with changes in CTmax owing to phenotypic plasticity, which suggests that there is likely mechanistic overlap between the effects of plasticity and adaptation. Together, these results indicate that developmental effects may have substantial impacts on upper thermal tolerance plasticity in adult ectotherms.
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Affiliation(s)
- Timothy M Healy
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive #0202, La Jolla, CA 92093-0202, USA
| | - Antonia K Bock
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive #0202, La Jolla, CA 92093-0202, USA
| | - Ronald S Burton
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive #0202, La Jolla, CA 92093-0202, USA
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16
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Giacomin M, Bryant HJ, Val AL, Schulte PM, Wood CM. The osmorespiratory compromise: physiological responses and tolerance to hypoxia are affected by salinity acclimation in the euryhaline Atlantic killifish ( Fundulus heteroclitus). ACTA ACUST UNITED AC 2019; 222:jeb.206599. [PMID: 31488621 DOI: 10.1242/jeb.206599] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Accepted: 09/03/2019] [Indexed: 12/16/2022]
Abstract
The characteristics of the fish gill that maximize gas exchange are the same that promote diffusion of ions and water to and from the environment; therefore, physiological trade-offs are likely to occur. Here, we investigated how salinity acclimation affects whole-animal respiratory gas exchange during hypoxia using Fundulus heteroclitus, a fish that inhabits salt marshes where salinity and oxygen levels vary greatly. Salinity had marked effects on hypoxia tolerance, with fish acclimated to 11 and 35 ppt showing much longer time to loss of equilibrium (LOE) in hypoxia than 0 ppt-acclimated fish. Fish acclimated to 11 ppt (isosmotic salinity) exhibited the greatest capacity to regulate oxygen consumption rate (Ṁ O2 ) under hypoxia, as measured through the regulation index (RI) and P crit At 35 ppt, fish had a higher routine metabolic rate (RMR) but a lower RI than fish at 11 ppt, but there were no differences in gill morphology, ventilation or blood O2 transport properties between these groups. In contrast, 0 ppt-acclimated fish had the highest ventilation and lowest O2 extraction efficiency in normoxia and hypoxia, indicating a higher ventilatory workload in order to maintain similar levels of Ṁ O2 These differences were related to alterations in gill morphology, where 0 ppt-acclimated fish had the smallest lamellar surface area with the greatest epithelial cell coverage (i.e. thicker lamellae, longer diffusion distance) and a larger interlamellar cell mass, contrasting with 11 ppt-acclimated fish, which had overall the highest respiratory surface area. The alteration of an array of physiological parameters provides evidence for a compromise between salinity and hypoxia tolerance in killifish acclimated to freshwater.
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Affiliation(s)
- Marina Giacomin
- Department of Zoology, The University of British Columbia, Vancouver, BC, Canada V6T 1Z4 .,Bamfield Marine Sciences Centre, Bamfield, BC, Canada V0R 1B0
| | - Heather J Bryant
- Department of Zoology, The University of British Columbia, Vancouver, BC, Canada V6T 1Z4
| | - Adalberto L Val
- Laboratory of Ecophysiology and Molecular Evolution, Instituto Nacional de Pesquisas da Amazônia (INPA), Manaus, Amazonas 69080-971, Brazil
| | - Patricia M Schulte
- Department of Zoology, The University of British Columbia, Vancouver, BC, Canada V6T 1Z4
| | - Chris M Wood
- Department of Zoology, The University of British Columbia, Vancouver, BC, Canada V6T 1Z4.,Bamfield Marine Sciences Centre, Bamfield, BC, Canada V0R 1B0.,Department of Biology, McMaster University, Hamilton, ON, Canada L8S 4K1
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17
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McKenzie JL, Chung DJ, Healy TM, Brennan RS, Bryant HJ, Whitehead A, Schulte PM. Mitochondrial Ecophysiology: Assessing the Evolutionary Forces That Shape Mitochondrial Variation. Integr Comp Biol 2019; 59:925-937. [PMID: 31282925 DOI: 10.1093/icb/icz124] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The mitonuclear species concept hypothesizes that incompatibilities between interacting gene products of the nuclear and mitochondrial genomes are a major factor establishing and maintaining species boundaries. However, most of the data available to test this concept come from studies of genetic variation in mitochondrial DNA, and clines in the mitochondrial genome across contact zones can be produced by a variety of forces. Here, we show that using a combination of population genomic analyses of the nuclear and mitochondrial genomes and studies of mitochondrial function can provide insight into the relative roles of neutral processes, adaptive evolution, and mitonuclear incompatibility in establishing and maintaining mitochondrial clines, using Atlantic killifish (Fundulus heteroclitus) as a case study. There is strong evidence for a role of secondary contact following the last glaciation in shaping a steep mitochondrial cline across a contact zone between northern and southern subspecies of killifish, but there is also evidence for a role of adaptive evolution in driving differentiation between the subspecies in a variety of traits from the level of the whole organism to the level of mitochondrial function. In addition, studies are beginning to address the potential for mitonuclear incompatibilities in admixed populations. However, population genomic studies have failed to detect evidence for a strong and pervasive influence of mitonuclear incompatibilities, and we suggest that polygenic selection may be responsible for the complex patterns observed. This case study demonstrates that multiple forces can act together in shaping mitochondrial clines, and illustrates the challenge of disentangling their relative roles.
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Affiliation(s)
- Jessica L McKenzie
- Department of Zoology and Biodiversity Research Centre, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Dillon J Chung
- Department of Zoology and Biodiversity Research Centre, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Timothy M Healy
- Department of Zoology and Biodiversity Research Centre, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Reid S Brennan
- Department of Environmental Toxicology, University of California-Davis, 4138 Meyer Hall, 1 Shields Avenue, Davis, CA 95616, USA
| | - Heather J Bryant
- Department of Zoology and Biodiversity Research Centre, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Andrew Whitehead
- Department of Environmental Toxicology, University of California-Davis, 4138 Meyer Hall, 1 Shields Avenue, Davis, CA 95616, USA
| | - Patricia M Schulte
- Department of Zoology and Biodiversity Research Centre, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada
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18
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Harada AE, Healy TM, Burton RS. Variation in Thermal Tolerance and Its Relationship to Mitochondrial Function Across Populations of Tigriopus californicus. Front Physiol 2019; 10:213. [PMID: 30930787 PMCID: PMC6429002 DOI: 10.3389/fphys.2019.00213] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 02/19/2019] [Indexed: 12/22/2022] Open
Abstract
Variation in thermal tolerance plays a key role in determining the biogeographic distribution of organisms. Consequently, identifying the mechanistic basis for thermal tolerance is necessary for understanding not only current species range limits but also the capacity for range limits to shift in response to climate change. Although variation in mitochondrial function likely contributes to variation in thermal tolerance, the extent to which mitochondrial function underlies local thermal adaptation is not fully understood. In the current study, we examine variation in thermal tolerance and mitochondrial function among three populations of the intertidal copepod Tigriopus californicus found across a latitudinal thermal gradient along the coast of California, USA. We tested (1) acute thermal tolerance using survivorship and knockdown assays, (2) chronic thermal tolerance using survivorship of nauplii and developmental rate, and (3) mitochondrial performance at a range of temperatures using ATP synthesis fueled by complexes I, II, and I&II, as well as respiration of permeabilized fibers. We find evidence for latitudinal thermal adaptation: the southernmost San Diego population outperforms the northernmost Santa Cruz in measures of survivorship, knockdown temperature, and ATP synthesis rates during acute thermal exposures. However, under a chronic thermal regime, survivorship and developmental rate are more similar in the southernmost and northernmost population than in the mid-range population (Abalone Cove). Though this pattern is unexpected, it aligns well with population-specific rates of ATP synthesis at these chronic temperatures. Combined with the tight correlation of ATP synthesis decline and knockdown temperature, these data suggest a role for mitochondria in setting thermal range limits and indicate that divergence in mitochondrial function is likely a component of adaptation across latitudinal thermal gradients.
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Affiliation(s)
- Alice E Harada
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, United States
| | - Timothy M Healy
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, United States
| | - Ronald S Burton
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, United States
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19
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Chung DJ, Healy TM, McKenzie JL, Chicco AJ, Sparagna GC, Schulte PM. Mitochondria, Temperature, and the Pace of Life. Integr Comp Biol 2018; 58:578-590. [DOI: 10.1093/icb/icy013] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Affiliation(s)
- Dillon J Chung
- Department of Zoology and Biodiversity Research Centre, The University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
| | - Timothy M Healy
- Department of Zoology and Biodiversity Research Centre, The University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, CA 92037, USA
| | - Jessica L McKenzie
- Department of Zoology and Biodiversity Research Centre, The University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
| | - Adam J Chicco
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO 80523-1680, USA
| | - Genevieve C Sparagna
- Anschutz Medical Campus, Division of Cardiology, University of Colorado Denver, Aurora, CO 80045, USA
| | - Patricia M Schulte
- Department of Zoology and Biodiversity Research Centre, The University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
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20
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Chung DJ, Sparagna GC, Chicco AJ, Schulte PM. Patterns of mitochondrial membrane remodeling parallel functional adaptations to thermal stress. J Exp Biol 2018; 221:221/7/jeb174458. [DOI: 10.1242/jeb.174458] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 02/14/2018] [Indexed: 01/07/2023]
Abstract
ABSTRACT
The effect of temperature on mitochondrial performance is thought to be partly due to its effect on mitochondrial membranes. Numerous studies have shown that thermal acclimation and adaptation can alter the amount of inner-mitochondrial membrane (IMM), but little is known about the capacity of organisms to modulate mitochondrial membrane composition. Using northern and southern subspecies of Atlantic killifish (Fundulus heteroclitus) that are locally adapted to different environmental temperatures, we assessed whether thermal acclimation altered liver mitochondrial respiratory capacity or the composition and amount of IMM. We measured changes in phospholipid headgroups and headgroup-specific fatty acid (FA) remodeling, and used respirometry to assess mitochondrial respiratory capacity. Acclimation to 5°C and 33°C altered mitochondrial respiratory capacity in both subspecies. Northern F. heteroclitus exhibited greater mitochondrial respiratory capacity across acclimation temperatures, consistent with previously observed subspecies differences in whole-organism aerobic metabolism. Mitochondrial phospholipids were altered following thermal acclimation, and the direction of these changes was largely consistent between subspecies. These effects were primarily driven by remodeling of specific phospholipid classes and were associated with shifts in metabolic phenotypes. There were also differences in membrane composition between subspecies that were driven largely by differences in phospholipid classes. Changes in respiratory capacity between subspecies and with acclimation were largely but not completely accounted for by alterations in the amount of IMM. Taken together, these results support a role for changes in liver mitochondrial function in the ectothermic response to thermal stress during both acclimation and adaptation, and implicate lipid remodeling as a mechanism contributing to these changes.
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Affiliation(s)
- Dillon J. Chung
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
| | - Genevieve C. Sparagna
- Department of Medicine/Division of Cardiology, University of Colorado Anschutz Medical Center, Aurora, CO 80045, USA
| | - Adam J. Chicco
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO 80523-1680, USA
| | - Patricia M. Schulte
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
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