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Jóhannsson F, Yurkovich JT, Guðmundsson S, Sigurjónsson ÓE, Rolfsson Ó. Temperature Dependence of Platelet Metabolism. Metabolites 2024; 14:91. [PMID: 38392983 PMCID: PMC10890334 DOI: 10.3390/metabo14020091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 01/16/2024] [Accepted: 01/19/2024] [Indexed: 02/25/2024] Open
Abstract
Temperature plays a fundamental role in biology, influencing cellular function, chemical reaction rates, molecular structures, and interactions. While the temperature dependence of many biochemical reactions is well defined in vitro, the effect of temperature on metabolic function at the network level is poorly understood, and it remains an important challenge in optimizing the storage of cells and tissues at lower temperatures. Here, we used time-course metabolomic data and systems biology approaches to characterize the effects of storage temperature on human platelets (PLTs) in a platelet additive solution. We observed that changes to the metabolome with storage time do not simply scale with temperature but instead display complex temperature dependence, with only a small subset of metabolites following an Arrhenius-type relationship. Investigation of PLT energy metabolism through integration with computational modeling revealed that oxidative metabolism is more sensitive to temperature changes than glycolysis. The increased contribution of glycolysis to ATP turnover at lower temperatures indicates a stronger glycolytic phenotype with decreasing storage temperature. More broadly, these results demonstrate that the temperature dependence of the PLT metabolic network is not uniform, suggesting that efforts to improve the health of stored PLTs could be targeted at specific pathways.
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Affiliation(s)
- Freyr Jóhannsson
- Center for Systems Biology, University of Iceland, Sturlugata 8, 102 Reykjavik, Iceland
- School of Health Sciences, Medical Department, University of Iceland, Sturlugata 8, 102 Reykjavik, Iceland
| | - James T Yurkovich
- Department of Bioengineering, University of California San Diego, La Jolla, CA 92093, USA
- Phenome Health, Seattle, WA 98109, USA
- Center for Phenomic Health, The Buck Institute for Research on Aging, Novato, CA 94945, USA
| | - Steinn Guðmundsson
- Center for Systems Biology, University of Iceland, Sturlugata 8, 102 Reykjavik, Iceland
- Faculty of Industrial Engineering, Mechanical Engineering and Computer Science, University of Iceland, Dunhagi 3, 107 Reykjavik, Iceland
| | - Ólafur E Sigurjónsson
- The Blood Bank, Landspitali-University Hospital, Snorrabraut 60, 101 Reykjavik, Iceland
- School of Science and Engineering, Reykjavik University, Menntavegur 1, 102 Reykjavik, Iceland
| | - Óttar Rolfsson
- Center for Systems Biology, University of Iceland, Sturlugata 8, 102 Reykjavik, Iceland
- School of Health Sciences, Medical Department, University of Iceland, Sturlugata 8, 102 Reykjavik, Iceland
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2
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Li L, Liu Z, Zhao G, Quan J, Sun J, Lu J. Nano-selenium Antagonizes Heat Stress-Induced Apoptosis of Rainbow Trout (Oncorhynchus mykiss) Hepatocytes by Activating the PI3K/AKT Pathway. Biol Trace Elem Res 2023; 201:5805-5815. [PMID: 36973607 DOI: 10.1007/s12011-023-03637-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 03/15/2023] [Indexed: 03/29/2023]
Abstract
The cold-water fish rainbow trout (Oncorhynchus mykiss) shows poor resistance to heat, which is the main factor restricting their survival and yield. With the advancement of nanotechnology, nano-selenium (nano-Se) has emerged as a key nano-trace element, showing unique advantages, including high biological activity and low toxicity, for studying the response of animals to adverse environmental conditions. However, little is still known regarding the potential protective mechanisms of nano-Se against heat stress-induced cellular damage. Herein, we aimed to investigate the mechanism underlying the antagonistic effects of nano-Se on heat stress. Four groups were assessed: CG18 (0 μg/mL nano-Se, 18 °C), Se18 (5.0 μg/mL nano-Se, 18 °C), CG24 (0 μg/mL nano-Se, incubated at 18 °C for 24 h and then transferred to 24 °C culture), and Se24 (5.0 μg/mL nano-Se, incubated at 18 °C for 24 h and then transferred to 24 °C culture). We found that after heat treatment (CG24 group), T-AOC, GPx, and CAT activities in rainbow trout hepatocytes showed a decrease of 36%, 33%, and 19%, respectively, while ROS and MDA levels showed an increase of 67% and 93%, respectively (P < 0.05). Meanwhile, the mRNA levels of the apoptosis-related genes caspase3, caspase9, Cyt-c, Bax, and Bax/Bcl-2 in the CG24 group were 41%, 47%, 285%, 65%, and 151% higher than those in the CG18 group, respectively, while those of PI3K and AKT were 31% and 17% lower, respectively (P < 0.05). Besides, flow cytometry analysis showed an increase in the level of apoptotic cells after heat exposure. More importantly, we observed that nano-Se cotreatment (Se24 group) remarkably attenuated heat stress-induced effects (P < 0.05). We conclude that heat stress induces oxidative stress and apoptosis in rainbow trout hepatocytes. Nano-Se ameliorates heat stress-induced apoptosis by activating the PI3K/AKT pathway. Our results provide a new perspective to improve our understanding of the ability of nano-Se to confer heat stress resistance.
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Affiliation(s)
- Lanlan Li
- College of Animal Science & Technology, Gansu Agricultural University, No. 1 Yingmen Village, Anning District, Lanzhou, 730070, Gansu Province, China
| | - Zhe Liu
- College of Animal Science & Technology, Gansu Agricultural University, No. 1 Yingmen Village, Anning District, Lanzhou, 730070, Gansu Province, China.
| | - Guiyan Zhao
- College of Animal Science & Technology, Gansu Agricultural University, No. 1 Yingmen Village, Anning District, Lanzhou, 730070, Gansu Province, China
| | - Jinqiang Quan
- College of Animal Science & Technology, Gansu Agricultural University, No. 1 Yingmen Village, Anning District, Lanzhou, 730070, Gansu Province, China
| | - Jun Sun
- College of Animal Science & Technology, Gansu Agricultural University, No. 1 Yingmen Village, Anning District, Lanzhou, 730070, Gansu Province, China
| | - Junhao Lu
- College of Animal Science & Technology, Gansu Agricultural University, No. 1 Yingmen Village, Anning District, Lanzhou, 730070, Gansu Province, China
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3
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Onukwufor JO, Somo DA, Richards JG, Wood CM. Osmo-respiratory compromise in the mosshead sculpin (Clinocottus globiceps): effects of temperature, hypoxia, and re-oxygenation on rates of diffusive water flux and oxygen uptake. FISH PHYSIOLOGY AND BIOCHEMISTRY 2023; 49:853-866. [PMID: 37526893 DOI: 10.1007/s10695-023-01226-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 07/28/2023] [Indexed: 08/02/2023]
Abstract
In nature, mosshead sculpins (Clinocottus globiceps) are challenged by fluctuations in temperature and oxygen levels in their environment. However, it is unclear how mosshead sculpins modulate the permeability of their branchial epithelia to water and O2 in response to temperature or hypoxia stress. Acute decrease in temperature from 13 to 6 oC reduced diffusive water flux rate by 22% and ṀO2 by 51%, whereas acute increase in temperature from 13 to 25 oC increased diffusive water flux rate by 217% and ṀO2 by 140%, yielding overall Q10 values of 2.08 and 2.47 respectively. Acute reductions in oxygen tension from >95% to 20% or 10% air saturation did not impact diffusive water flux rates, however, ṀO2 was reduced significantly by 36% and 65% respectively. During 1-h or 3-h recovery periods diffusive water flux rates were depressed while ṀO2 exhibited overshoots beyond the normoxic control level. Many responses differed from those seen in our parallel earlier study on the tidepool sculpin, a cottid with similar hypoxia tolerance but much smaller gill area that occupies a similar environment. Overall, our data suggest that during temperature stress, diffusive water flux rates and ṀO2 follow the traditional osmo-respiratory compromise pattern, but during hypoxia and re-oxygenation stress, diffusive water flux rates are decoupled from ṀO2.
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Affiliation(s)
- John O Onukwufor
- Department of Zoology, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY, 14642, USA.
| | - Derek A Somo
- Department of Zoology, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Jeffrey G Richards
- Department of Zoology, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Chris M Wood
- Department of Zoology, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
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4
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Osmorespiratory compromise in an elasmobranch: oxygen consumption, ventilation and nitrogen metabolism during recovery from exhaustive exercise in dogfish sharks (Squalus suckleyi). J Comp Physiol B 2022; 192:647-657. [PMID: 35838789 DOI: 10.1007/s00360-022-01447-4] [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: 01/11/2022] [Revised: 05/30/2022] [Accepted: 06/15/2022] [Indexed: 10/17/2022]
Abstract
The functional trade-off between respiratory gas exchange versus osmolyte and water balance that occurs at the thin, highly vascularized gills of fishes has been termed the osmorespiratory compromise. Increases in gas exchange capacity for meeting elevated oxygen demands can end up favoring the passive movement of osmolytes and water, potentially causing a disturbance in osmotic balance. This phenomenon has been studied only sparsely in marine elasmobranchs. Our goal was to evaluate the effects of exhaustive exercise (as a modulator of oxygen demand) on oxygen consumption (MO2), branchial losses of nitrogenous products (ammonia and urea-N), diffusive water exchange rates, and gill ventilation (frequency and amplitude), in the Pacific spiny dogfish (Squalus suckleyi). To that end, MO2, osmolyte fluxes, diffusive water exchange rate, and ventilation dynamics were first measured under resting control conditions, then sharks were exercised until exhaustion (20 min), and the same parameters were monitored for the subsequent 4 h of recovery. While MO2 nearly doubled immediately after exercise and remained elevated for 2 h, ventilation dynamics did not change, suggesting that fish were increasing oxygen extraction efficiency at the gills. Diffusive water flux rates (measured over 0-2 h of recovery) were not affected. Ammonia losses were elevated by 7.6-fold immediately after exercise and remained elevated for 3 h into recovery, while urea-N losses were elevated only 1.75-fold and returned to control levels after 1 h. These results are consistent with previous investigations using different challenges (hypoxia, high temperature) and point to a tighter regulation of urea-N conservation mechanisms at the gills, likely due to the use of urea as a prized osmolyte in elasmobranchs. Environmental hyperoxia offered no relief from the osmorespiratory compromise, as there were no effects on any of the parameters measured during recovery from exhaustive exercise.
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Heinichen M, McManus MC, Lucey SM, Aydin K, Humphries A, Innes-Gold A, Collie J. Incorporating temperature-dependent fish bioenergetics into a Narragansett Bay food web model. Ecol Modell 2022. [DOI: 10.1016/j.ecolmodel.2022.109911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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6
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Ste-Marie E, Watanabe YY, Semmens JM, Marcoux M, Hussey NE. Life in the slow lane: Field Metabolic Rate and Prey Consumption Rate of the Greenland Shark (Somniosus microcephalus) modeled using Archival Biologgers. J Exp Biol 2022; 225:274642. [PMID: 35258589 DOI: 10.1242/jeb.242994] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 02/24/2022] [Indexed: 11/20/2022]
Abstract
Field metabolic rate (FMR) is a holistic measure of metabolism representing the routine energy utilization of a species living within a specific ecological context, thus providing insight into its ecology, fitness and resilience to environmental stressors. For animals which cannot be easily observed in the wild, FMR can also be used in concert with dietary data to quantitatively assess their role as consumers, improving understanding of the trophic linkages that structure food webs and allowing for informed management decisions. Here we modeled the FMR of Greenland sharks (Somniosus microcephalus) equipped with biologger packages or pop-up archival satellite tags (PSATs) in two coastal inlets of Baffin Island (Nunavut) using metabolic scaling relationships for mass, temperature and activity. We estimated that Greenland sharks had an overall mean FMR of 21.67±2.30 mgO2h-1kg-0.84 (n=30; 1-4 day accelerometer package deployments) while residing inside these cold-water fjord systems in the late summer, and 25.48±0.47 mgO2h-1kg-0.84 (n=6; PSATs) over an entire year. When considering prey consumption rate, an average shark in these systems (224kg) requires a maintenance ration of 61-193g of fish or marine mammal prey daily. As a lethargic polar species, these low FMR estimates, and corresponding prey consumption estimates suggest Greenland sharks require very little energy to sustain themselves under natural conditions. These data provide the first characterization of the energetics and consumer role of this vulnerable and understudied species in the wild, essential given growing pressures from climate change and expanding commercial fisheries in the Arctic.
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Affiliation(s)
- Eric Ste-Marie
- Department of Integrative Biology, University of Windsor, Windsor, ON, N9B 3P4, Canada
| | - Yuuki Y Watanabe
- National Institute of Polar Research, Tachikawa, Tokyo, 190-8518, Japan.,Department of Polar Science, The Graduate University for Advanced Studies, SOKENDAI, Tachikawa, Tokyo, 190-8518, Japan
| | - Jayson M Semmens
- Fisheries and Aquaculture Centre, Institute for Marine and Antarctic Studies, University of Tasmania, Taroona, TAS, 7053, Australia
| | - Marianne Marcoux
- Freshwater Institute, Fisheries and Oceans Canada, 501 University Crescent, Winnipeg, MB, R3T 2N6, Canada
| | - Nigel E Hussey
- Department of Integrative Biology, University of Windsor, Windsor, ON, N9B 3P4, Canada
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7
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Wood CM, Eom J. The osmorespiratory compromise in the fish gill. Comp Biochem Physiol A Mol Integr Physiol 2021; 254:110895. [PMID: 33429056 DOI: 10.1016/j.cbpa.2021.110895] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 12/30/2020] [Accepted: 12/31/2020] [Indexed: 01/17/2023]
Abstract
August Krogh made fundamental discoveries about both respiratory gas exchange and osmo/iono-regulation in fish gills. Dave Randall and co-workers identified a tradeoff between these two functions such that high functional surface area and low diffusion distance would favour O2 uptake (e.g. exercise, hypoxia), whereas low functional surface area and high diffusion distance would favour osmo/iono-regulation (rest, normoxia). Today we call this concept the "osmorespiratory compromise" and realize that it is much more complex than originally envisaged. There are at least 6 mechanisms by which fish can change functional branchial area and diffusion distance. Three involve reorganizing blood flow pathways: (i) flow redistribution within the secondary (respiratory) lamellae; (ii) flow shunting between "respiratory" and "ionoregulatory" pathways in the filament; (iii) opening up more distal lamellae on the filament and closing non-respiratory pathways. Three more involve "reversible gill remodeling": (iv) proliferation of the interlamellar gill cell mass (ILCM); (v) proliferation of ionocytes up the sides of the lamellae; (vi) covering over the apical exposure of ionocytes by extension of pavement cells. In ways that remain incompletely understood, these mechanisms allow dynamic regulation of the osmorespiratory compromise, such that ion and water fluxes can be decoupled from O2 uptake during continuous exercise. Furthermore, hypoxia-tolerant species can reduce branchial ion and water fluxes below normoxic levels despite hyperventilating during hypoxia. In marine fish, the osmorespiratory conflict is intensified by the greater ionic and osmotic gradients from seawater to blood, but underlying mechanisms remain poorly understood.
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Affiliation(s)
- Chris M Wood
- Department of Zoology, University of British Columbia, Vancouver, BC V6T1Z4, Canada.
| | - Junho Eom
- Department of Zoology, University of British Columbia, Vancouver, BC V6T1Z4, Canada
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8
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Onukwufor JO, Wood CM. Osmorespiratory Compromise in Zebrafish (Danio rerio): Effects of Hypoxia and Acute Thermal Stress on Oxygen Consumption, Diffusive Water Flux, and Sodium Net Loss Rates. Zebrafish 2020; 17:400-411. [DOI: 10.1089/zeb.2020.1947] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Affiliation(s)
- John O. Onukwufor
- Department of Anesthesiology and Perioperative Medicine, University of Rochester Medical Center, Rochester, New York, USA
- Department of Zoology, University of British Columbia, Vancouver, Canada
| | - Chris M. Wood
- Department of Zoology, University of British Columbia, Vancouver, Canada
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9
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A first look at the metabolic rate of Greenland sharks (Somniosus microcephalus) in the Canadian Arctic. Sci Rep 2020; 10:19297. [PMID: 33168918 PMCID: PMC7653932 DOI: 10.1038/s41598-020-76371-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 10/23/2020] [Indexed: 12/16/2022] Open
Abstract
Metabolic rate is intricately linked to the ecology of organisms and can provide a framework to study the behaviour, life history, population dynamics, and trophic impact of a species. Acquiring measures of metabolic rate, however, has proven difficult for large water-breathing animals such as sharks, greatly limiting our understanding of the energetic lives of these highly threatened and ecologically important fish. Here, we provide the first estimates of resting and active routine metabolic rate for the longest lived vertebrate, the Greenland shark (Somniosus microcephalus). Estimates were acquired through field respirometry conducted on relatively large-bodied sharks (33–126 kg), including the largest individual shark studied via respirometry. We show that despite recording very low whole-animal resting metabolic rates for this species, estimates are within the confidence intervals predicted by derived interspecies allometric and temperature scaling relationships, suggesting this species may not be unique among sharks in this respect. Additionally, our results do not support the theory of metabolic cold adaptation which assumes that polar species maintain elevated metabolic rates to cope with the challenges of life at extreme cold temperatures.
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Somo DA, Onukwufor JO, Wood CM, Richards JG. Interactive effects of temperature and hypoxia on diffusive water flux and oxygen uptake rate in the tidepool sculpin, Oligocottus maculosus. Comp Biochem Physiol A Mol Integr Physiol 2020; 250:110781. [PMID: 32763468 DOI: 10.1016/j.cbpa.2020.110781] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 07/31/2020] [Accepted: 07/31/2020] [Indexed: 01/07/2023]
Abstract
The osmorespiratory compromise hypothesis posits that respiratory epithelial characteristics and physiological regulatory mechanisms which promote gas permeability also increase permeability to ions and water. The hypothesis therefore predicts that physiological responses which increase effective gas permeability will result in increased effective ion and water permeabilities. Though analyses of water and gas effective permeabilities using high temperature have generally supported the hypothesis, water permeability responses to hypoxia remain equivocal and the combination of high temperature and hypoxia untested. We measured diffusive water flux (DWF) and oxygen uptake rate (Ṁo2) in response to acute temperature change, hypoxia, and the combination of high temperature and hypoxia in a hypoxia-tolerant intertidal fish, the tidepool sculpin (Oligocottus maculosus). In support of the osmorespiratory compromise hypothesis, Ṁo2 and DWF increased with temperature. In contrast, DWF decreased with hypoxia at a constant temperature, a result consistent with previously observed decoupling of water and gas effective permeabilities during hypoxia exposure in some hypoxia tolerant fishes. However, DWF levels during simultaneous high temperature and hypoxia exposure were not different from fish exposed to high temperature in normoxia, possibly suggesting a failure of the mechanism responsible for down-regulating DWF in hypoxia. These results, together with time-course analysis of hypoxia exposure and normoxic recovery, suggest that tidepool sculpins actively downregulate effective water permeability in hypoxia but the mechanism fails with multi-stressor exposure. Future investigations of the mechanistic basis of the regulation of gill permeability will be key to understanding the role of this regulatory ability in the persistence of this species in the dynamic intertidal environment.
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Affiliation(s)
- Derek A Somo
- Department of Zoology, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada.
| | - John O Onukwufor
- Department of Zoology, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Chris M Wood
- Department of Zoology, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Jeffrey G Richards
- Department of Zoology, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada
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Onukwufor JO, Wood CM. Reverse translation: effects of acclimation temperature and acute temperature challenges on oxygen consumption, diffusive water flux, net sodium loss rates, Q 10 values and mass scaling coefficients in the rainbow trout (Oncorhynchus mykiss). J Comp Physiol B 2020; 190:205-217. [PMID: 31965230 DOI: 10.1007/s00360-020-01259-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 12/17/2019] [Accepted: 01/09/2020] [Indexed: 01/04/2023]
Abstract
Our understanding is limited on how fish adjust the effective permeability of their branchial epithelium to ions and water while altering O2 uptake rate (MO2) with acute and chronic changes in temperature. We investigated the effects of acclimation temperature (8 °C, 13 °C and 18 °C) and acute temperature challenges [acute rise (acclimated at 8 °C, measured at 13 °C and 18 °C), acute drop (acclimated at 18 °C, measured at 8 °C and 13 °C) and intermediate (acclimated at 13 °C, measured at 8 °C and 18 °C)] on routine MO2, diffusive water flux, and net sodium loss rates in 24-h fasted rainbow trout (Oncorhynchus mykiss). In the temperature challenge tests, measurements were made during the first hour. In acclimated trout at all temperatures, allometric mass scaling coefficients were much higher for diffusive water flux than for MO2. Furthermore, the diffusive water flux rate was more responsive (overall Q10 = 2.75) compared to MO2 (Q10 = 1.80) over the 8-18 °C range, and for both, Q10 values were greater at 8-13 °C than at 13-18 °C. The net Na+ flux rates were highly sensitive to acclimation temperature with an overall Q10 of 3.01 for 8-18 °C. In contrast, very different patterns occurred in trout subjected to acute temperature challenges. The net Na+ flux rate was temperature-insensitive with a Q10 around 1.0. Both MO2 and diffusive water flux rates exhibited lower Q10 values than for the acclimated rates in response to either acute increases or decreases in temperature. These results fit Pattern 5 of Precht (undercompensation, reverse effect) and more precisely Pattern IIB of Prosser (reverse translation). These inverse compensatory patterns suggest that trout do not alter their rates very much when undergoing acute thermal challenges (diurnal fluctuations, migration through the thermocline). The greater changes seen with acclimation may be adaptive to long-term seasonal changes in temperature. We discuss the roles of aquaporins, spontaneous activity, and recent feeding in these responses.
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Affiliation(s)
- John O Onukwufor
- Department of Anesthesiology and Perioperative Medicine, University of Rochester Medical Center, Rochester, NY, 14642, USA.
- Department of Zoology, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.
| | - Chris M Wood
- Department of Zoology, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
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12
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Giacomin M, Onukwufor JO, Schulte PM, Wood CM. Ionoregulatory aspects of the hypoxia-induced osmorespiratory compromise in the euryhaline Atlantic killifish (Fundulus heteroclitus): the effects of salinity. J Exp Biol 2020; 223:jeb.216309. [DOI: 10.1242/jeb.216309] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 05/26/2020] [Indexed: 12/20/2022]
Abstract
The osmorespiratory compromise is a physiological trade-off between the characteristics of the gill that promote respiratory gas-exchange and those that limit passive fluxes of ions and water with the environment. In hypoxia, changes in gill blood flow patterns and functional surface area that increase gas transfer can promote an exacerbation in ion and water fluxes. Our goal was to determine whether the osmorespiratory compromise is flexible, depending on environmental salinity (fresh, isosmotic and sea water) and oxygen levels (hypoxia) in euryhaline killifish, Fundulus heteroclitus. Plasma ion concentrations were minimally affected by hypoxia, indicating a maintenance of osmoregulatory homeostasis. In FW-killifish, hypoxia exposure reduced branchial Na+/K+-ATPase and NEM-sensitive-ATPase activities, as well as diffusive water flux rates. Unidirectional Na+ influx and Na+ efflux decreased during hypoxia in FW, but net Na+ flux remained unchanged. Net loss rates of Cl−, K+ and ammonia were also attenuated in hypoxia, suggesting both transcellular and paracellular reductions in permeability. These reductions appeared to be regulated phenomena as fluxes were restored immediately in normoxia. Na+ flux rates increased during hypoxia in 11 ppt, but decreased in 35 ppt, the latter suggesting a similar response to hypoxia as in FW. In summary, FW- and SW-killifish experience a reduction in gill permeability, as seen in other hypoxia-tolerant species. Fish acclimated to isosmotic salinity increased Na+ influx and efflux rates, as well as paracellular permeability in hypoxia, responses in accord with the predictions of the classic osmorespiratory compromise.
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Affiliation(s)
- Marina Giacomin
- Department of Zoology, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - John O. Onukwufor
- Department of Zoology, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
- Department of Anesthesiology and Perioperative Medicine, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Patricia M. Schulte
- Department of Zoology, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Chris M. Wood
- Department of Zoology, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
- Department of Biology, McMaster University, Hamilton, ON, L8S 4K1, Canada
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Giacomin M, Dal Pont G, Eom J, Schulte PM, Wood CM. The effects of salinity and hypoxia exposure on oxygen consumption, ventilation, diffusive water exchange and ionoregulation in the Pacific hagfish (Eptatretus stoutii). Comp Biochem Physiol A Mol Integr Physiol 2019; 232:47-59. [PMID: 30878760 DOI: 10.1016/j.cbpa.2019.03.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 01/30/2019] [Accepted: 03/06/2019] [Indexed: 10/27/2022]
Abstract
Hagfishes (Class: Myxini) are marine jawless craniate fishes that are widely considered to be osmoconformers whose plasma [Na+], [Cl-] and osmolality closely resemble that of sea water, although they have the ability to regulate plasma [Ca2+] and [Mg2+] below seawater levels. We investigated the responses of Pacific hagfish to changes in respiratory and ionoregulatory demands imposed by a 48-h exposure to altered salinity (25 ppt, 30 ppt (control) and 35 ppt) and by an acute hypoxia exposure (30 Torr; 4 kPa). When hagfish were exposed to 25 ppt, oxygen consumption rate (MO2), ammonia excretion rate (Jamm) and unidirectional diffusive water flux rate (JH2O, measured with 3H2O) were all reduced, pointing to an interaction between ionoregulation and gas exchange. At 35 ppt, JH2O was reduced, though MO2 and Jamm did not change. As salinity increased, so did the difference between plasma and external water [Ca2+] and [Mg2+]. Notably, the same pattern was seen for plasma Cl-, which was kept below seawater [Cl-] at all salinities, while plasma [Na+] was regulated well above seawater [Na+], but plasma osmolality matched seawater values. MO2 was reduced by 49% and JH2O by 36% during hypoxia, despite a small elevation in overall ventilation. Our results depart from the "classical" osmorespiratory compromise but are in accord with responses in other hypoxia-tolerant fish; instead of an exacerbation of gill fluxes when gas transfer is upregulated, the opposite happens.
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Affiliation(s)
- Marina Giacomin
- Department of Zoology, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Bamfield Marine Sciences Centre, Bamfield, British Columbia V0R 1B0, Canada.
| | - Giorgi Dal Pont
- Department of Zoology, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Bamfield Marine Sciences Centre, Bamfield, British Columbia V0R 1B0, Canada; Integrated Group for Aquaculture and Environmental Studies, Department of Animal Science, Federal University of Paraná, Curitiba, Paraná 83035-050, Brazil
| | - Junho Eom
- Department of Zoology, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Bamfield Marine Sciences Centre, Bamfield, British Columbia V0R 1B0, Canada.
| | - Patricia M Schulte
- Department of Zoology, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada.
| | - Chris M Wood
- Department of Zoology, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Bamfield Marine Sciences Centre, Bamfield, British Columbia V0R 1B0, Canada; Department of Biology, McMaster University, Hamilton, Ontario L8S 4K1, Canada.
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Giacomin M, Eom J, Schulte PM, Wood CM. Acute temperature effects on metabolic rate, ventilation, diffusive water exchange, osmoregulation, and acid–base status in the Pacific hagfish (Eptatretus stoutii). J Comp Physiol B 2018; 189:17-35. [DOI: 10.1007/s00360-018-1191-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 10/30/2018] [Accepted: 11/05/2018] [Indexed: 12/21/2022]
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15
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The osmorespiratory compromise in rainbow trout ( Oncorhynchus mykiss ): The effects of fish size, hypoxia, temperature and strenuous exercise on gill diffusive water fluxes and sodium net loss rates. Comp Biochem Physiol A Mol Integr Physiol 2018; 219-220:10-18. [DOI: 10.1016/j.cbpa.2018.02.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 02/02/2018] [Accepted: 02/02/2018] [Indexed: 11/18/2022]
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