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Polymeropoulos ET, Milsom WK. Editorial: Untangling the oxygen transport cascade: a tribute to Peter Frappell (Frapps). J Comp Physiol B 2021; 191:973-978. [PMID: 34463812 DOI: 10.1007/s00360-021-01401-w] [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: 08/02/2021] [Revised: 08/15/2021] [Accepted: 08/18/2021] [Indexed: 10/20/2022]
Abstract
This collection of research articles was put together in honour of respiratory physiologist Professor Peter Frappell's (Frapps's) academic achievements. It encompasses various topics relating to the oxygen transport cascade, which was central to Frapps' career as a comparative physiologist. This issue highlights the diversity and outreach of his influence on the field and his pioneering spirit; promoting novel perspectives, methodologies and research techniques. This issue also demonstrates how Frapps' knowledge and scientific findings answered some of the fundamental questions within the field of respiratory physiology while creating and fostering a rather unique work atmosphere in the laboratories he led. We thank Frapps for the contributions he has made and the friendships he has nurtured over his career. Cheers, Frapps - we love you mate!
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Affiliation(s)
- Elias T Polymeropoulos
- Institute for Marine and Antarctic Studies (IMAS), University of Tasmania, Hobart, TAS, 7001, Australia.
| | - William K Milsom
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
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Galli GLJ, Ruhr IM, Crossley J, Crossley DA. The Long-Term Effects of Developmental Hypoxia on Cardiac Mitochondrial Function in Snapping Turtles. Front Physiol 2021; 12:689684. [PMID: 34262478 PMCID: PMC8273549 DOI: 10.3389/fphys.2021.689684] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 06/03/2021] [Indexed: 01/05/2023] Open
Abstract
It is well established that adult vertebrates acclimatizing to hypoxic environments undergo mitochondrial remodeling to enhance oxygen delivery, maintain ATP, and limit oxidative stress. However, many vertebrates also encounter oxygen deprivation during embryonic development. The effects of developmental hypoxia on mitochondrial function are likely to be more profound, because environmental stress during early life can permanently alter cellular physiology and morphology. To this end, we investigated the long-term effects of developmental hypoxia on mitochondrial function in a species that regularly encounters hypoxia during development-the common snapping turtle (Chelydra serpentina). Turtle eggs were incubated in 21% or 10% oxygen from 20% of embryonic development until hatching, and both cohorts were subsequently reared in 21% oxygen for 8 months. Ventricular mitochondria were isolated, and mitochondrial respiration and reactive oxygen species (ROS) production were measured with a microrespirometer. Compared to normoxic controls, juvenile turtles from hypoxic incubations had lower Leak respiration, higher P:O ratios, and reduced rates of ROS production. Interestingly, these same attributes occur in adult vertebrates that acclimatize to hypoxia. We speculate that these adjustments might improve mitochondrial hypoxia tolerance, which would be beneficial for turtles during breath-hold diving and overwintering in anoxic environments.
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Affiliation(s)
- Gina L. J. Galli
- Faculty of Biology, Medicine, and Health, School of Medical Sciences, The University of Manchester, Manchester, United Kingdom
| | - Ilan M. Ruhr
- Faculty of Biology, Medicine, and Health, School of Medical Sciences, The University of Manchester, Manchester, United Kingdom
| | - Janna Crossley
- Developmental Integrative Biology Research Group, Department of Biological Sciences, University of North Texas, Denton, TX, United States
| | - Dane A. Crossley
- Developmental Integrative Biology Research Group, Department of Biological Sciences, University of North Texas, Denton, TX, United States
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Cochrane PV, Jonz MG, Wright PA. The development of the O 2-sensing system in an amphibious fish: consequences of variation in environmental O 2 levels. J Comp Physiol B 2021; 191:681-699. [PMID: 34023926 DOI: 10.1007/s00360-021-01379-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 03/04/2021] [Accepted: 05/07/2021] [Indexed: 11/25/2022]
Abstract
Proper development of the O2-sensing system is essential for survival. Here, we characterized the development of the O2-sensing system in the mangrove rivulus (Kryptolebias marmoratus), an amphibious fish that transitions between hypoxic aquatic environments and O2-rich terrestrial environments. We found that NECs formed in the gills and skin of K. marmoratus during embryonic development and that both NEC populations are retained from the embryonic stage to adulthood. We also found that the hyperventilatory response to acute hypoxia was present in embryonic K. marmoratus, indicating that functional O2-sensing pathways are formed during embryonic development. We then exposed embryos to aquatic normoxia, aquatic hyperoxia, aquatic hypoxia, or terrestrial conditions for the first 30 days of embryonic development and tested the hypothesis that environmental O2 availability during embryonic development modulates the development of the O2-sensing system in amphibious fishes. Surprisingly, we found that O2 availability during embryonic development had little impact on the density and morphology of NECs in the gills and skin of K. marmoratus. Collectively, our results demonstrate that, unlike the only other species of fish in which NEC development has been studied to date (i.e., zebrafish), NEC development in K. marmoratus is largely unaffected by environmental O2 levels during the embryonic stage, indicating that there is interspecies variation in O2-induced plasticity in the O2-sensing system of fishes.
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Affiliation(s)
- Paige V Cochrane
- Department of Integrative Biology, University of Guelph, Guelph, ON, N1G 2W1, Canada.
| | - Michael G Jonz
- Department of Biology, University of Ottawa, Ottawa, ON, K1N 6N5, Canada
| | - Patricia A Wright
- Department of Integrative Biology, University of Guelph, Guelph, ON, N1G 2W1, Canada
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Del Rio AM, Mukai GN, Martin BT, Johnson RC, Fangue NA, Israel JA, Todgham AE. Differential sensitivity to warming and hypoxia during development and long-term effects of developmental exposure in early life stage Chinook salmon. CONSERVATION PHYSIOLOGY 2021; 9:coab054. [PMID: 34257996 PMCID: PMC8271147 DOI: 10.1093/conphys/coab054] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 04/28/2021] [Accepted: 06/15/2021] [Indexed: 05/13/2023]
Abstract
Warming and hypoxia are two stressors commonly found within natural salmon redds that are likely to co-occur. Warming and hypoxia can interact physiologically, but their combined effects during fish development remain poorly studied, particularly stage-specific effects and potential carry-over effects. To test the impacts of warm water temperature and hypoxia as individual and combined developmental stressors, late fall-run Chinook salmon embryos were reared in 10 treatments from fertilization through hatching with two temperatures [10°C (ambient) and 14°C (warm)], two dissolved oxygen saturation levels [normoxia (100% air saturation, 10.4-11.4 mg O2/l) and hypoxia (50% saturation, 5.5 mg O2/l)] and three exposure times (early [eyed stage], late [silver-eyed stage] and chronic [fertilization through hatching]). After hatching, all treatments were transferred to control conditions (10°C and 100% air saturation) through the fry stage. To study stage-specific effects of stressor exposure we measured routine metabolic rate (RMR) at two embryonic stages, hatching success and growth. To evaluate carry-over effects, where conditions during one life stage influence performance in a later stage, RMR of all treatments was measured in control conditions at two post-hatch stages and acute stress tolerance was measured at the fry stage. We found evidence of stage-specific effects of both stressors during exposure and carry-over effects on physiological performance. Both individual stressors affected RMR, growth and developmental rate while multiple stressors late in development reduced hatching success. RMR post-hatch showed persistent effects of embryonic stressor exposure that may underlie differences observed in developmental timing and acute stress tolerance. The responses to stressors that varied by stage during development suggest that stage-specific management efforts could support salmon embryo survival. The persistent carry-over effects also indicate that considering sub-lethal effects of developmental stressor exposure may be important to understanding how climate change influences the performance of salmon across life stages.
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Affiliation(s)
- Annelise M Del Rio
- Department of Animal Science, University of California Davis, Davis, CA 95616, USA
| | - Gabriella N Mukai
- Department of Animal Science, University of California Davis, Davis, CA 95616, USA
- Department of Biology, University of Hawai’i at Mānoa, Honolulu, HI 96822, USA
| | - Benjamin T Martin
- University of California Santa Cruz, Cooperative Institute for Marine Ecosystems and Climate (CIMEC), Santa Cruz, CA 95064, USA
- Southwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 110 Shaffer Road, Santa Cruz, CA 95060, USA
- Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, 1098 XH Amsterdam, the Netherlands
| | - Rachel C Johnson
- Department of Animal Science, University of California Davis, Davis, CA 95616, USA
- University of California Santa Cruz, Cooperative Institute for Marine Ecosystems and Climate (CIMEC), Santa Cruz, CA 95064, USA
- Southwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 110 Shaffer Road, Santa Cruz, CA 95060, USA
| | - Nann A Fangue
- Department of Wildlife, Fish, and Conservation Biology, University of California Davis, Davis, CA 95616, USA
| | - Joshua A Israel
- Bay-Delta Office, U.S. Bureau of Reclamation, Sacramento, CA 95825, USA
| | - Anne E Todgham
- Department of Animal Science, University of California Davis, Davis, CA 95616, USA
- Corresponding author: Department of Animal Science, University of California Davis, Davis, CA 95616, USA.
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Low Oxygen Stress During Early Development Influences Regulation of Hypoxia-Response Genes in Farmed Atlantic Salmon ( Salmo salar). G3-GENES GENOMES GENETICS 2020; 10:3179-3188. [PMID: 32636218 PMCID: PMC7466997 DOI: 10.1534/g3.120.401459] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Survival and growth of developing salmonids are negatively affected by low oxygen levels within gravel nests in natural streams, and hypoxic stress is often experienced by farmed Atlantic salmon (Salmo salar) within hatcheries. Exposure to hypoxia during early development may have long-lasting effects by altering epigenetic marks and gene expression in oxygen regulatory pathways. Here, we examine the transcriptomic response to low dissolved oxygen (DO) in post-hatch salmon reared continuously in 30%, 60% or 100% DO from fertilization until start of feeding. RNA sequencing revealed multiple differentially expressed genes, including oxygen transporting hemoglobin embryonic α subunit (hbae) and EGLN3 family hypoxia-inducible factor 3 (egln3) which regulates the stability of hypoxia inducible factor 1α (HIF-1α). Both hbae and egln3 displayed expression levels inversely correlated to oxygen concentration, and DNA methylation patterns within the egln3 promoter were negatively associated with the transcript levels. These results suggest that epigenetic processes are influenced by low oxygen levels during early development in Atlantic salmon to upregulate hypoxia-response genes.
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Whitehouse LM, Faught E, Vijayan MM, Manzon RG. Hypoxia affects the ontogeny of the hypothalamus-pituitary-interrenal axis functioning in the lake whitefish (Coregonus clupeaformis). Gen Comp Endocrinol 2020; 295:113524. [PMID: 32526331 DOI: 10.1016/j.ygcen.2020.113524] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 04/20/2020] [Accepted: 05/26/2020] [Indexed: 01/08/2023]
Abstract
Early life stages are sensitive to environmental insults and changes during critical developmental periods; this can often result in altered adult behaviour and physiology. Examining the development of the hypothalamus-pituitary-interrenal (HPI) axis and its responsiveness, or lack thereof, during development are important for understanding the short- and long-term impacts of stressors on embryonic and larval fish. We examined the ontogeny of the HPI axis in embryonic (21, 38, 63, 83 and 103 days post-fertilisation (dpf)) and larval (1, 2, 3 and 4 weeks post-hatch (wph)) lake whitefish (Coregonus clupeaformis) by quantifying changes in mRNA levels of several genes associated with HPI axis functioning and whole animal cortisol levels throughout development and in response to a severe or mild hypoxic stress. Cortisol, and crh, crhbp1, pomc and star transcripts were detected from the earliest embryonic age studied. Cortisol levels in control embryos decreased between 21 and 63 dpf, suggesting the utilisation of maternal cortisol deposits. However, by 83 dpf (70% developed) endogenous de novo synthesis had generated a 4.5-fold increase in whole embryo cortisol. Importantly, we provide novel data showing that the HPI axis can be activated even earlier. Whole body cortisol increased in eyed lake whitefish embryos (38 dpf; ~32% developed) in response to hypoxia stress. Coincident with this hypoxia-induced increase in cortisol in 38 dpf embryos were corresponding increases in crh, crhbp1, pomc and star transcript levels. Beyond 38 dpf, the HPI axis in lake whitefish embryos was hyporesponsive to hypoxia stress at all embryonic ages examined (63, 83 and 103 dpf; 54, 72 and 85% developed, respectively). Post-hatch, larvae responded to hypoxia with an increase in cortisol levels and HPI axis genes at 1 wph, but this response was lost and larvae appeared hyporesponsive at subsequent ages (2, 3 and 4 wph). Collectively our work demonstrates that during fish embryogenesis and the larval stage there are windows where the HPI axis is responsive and windows where it is truly hyporesponsive; both could be beneficial in ensuring undisrupted development particularly in the face of increasing environmental changes.
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Affiliation(s)
- Lindy M Whitehouse
- Department of Biology, University of Regina, 3737 Wascana Parkway, Regina, SK S4S 0A2, Canada
| | - Erin Faught
- Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
| | - Mathilakath M Vijayan
- Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
| | - Richard G Manzon
- Department of Biology, University of Regina, 3737 Wascana Parkway, Regina, SK S4S 0A2, Canada.
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Wood AT, Andrewartha SJ, Elliott NG, Frappell PB, Clark TD. Hypoxia during incubation does not affect aerobic performance or haematology of Atlantic salmon ( Salmo salar) when re-exposed in later life. CONSERVATION PHYSIOLOGY 2019; 7:coz088. [PMID: 31798884 PMCID: PMC6880253 DOI: 10.1093/conphys/coz088] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 08/26/2019] [Accepted: 10/15/2019] [Indexed: 05/26/2023]
Abstract
Hypoxia in aquatic ecosystems is becoming increasingly prevalent, potentially reducing fish performance and survival by limiting the oxygen available for aerobic activities. Hypoxia is a challenge for conserving and managing fish populations and demands a better understanding of the short- and long-term impacts of hypoxic environments on fish performance. Fish acclimate to hypoxia via a variety of short- and long-term physiological modifications in an attempt to maintain aerobic performance. In particular, hypoxia exposure during early development may result in enduring cardio-respiratory modifications that affect future hypoxia acclimation capacity, yet this possibility remains poorly investigated. We incubated Atlantic salmon (Salmo salar) in normoxia (~100% dissolved oxygen [DO, as percent air saturation]), moderate hypoxia (~63% DO) or cyclical hypoxia (100-25% DO daily) from fertilization until 113 days post-fertilization prior to rearing all groups in normoxia for a further 8 months. At ~11 months of age, subsets of each group were acclimated to hypoxia (50% DO) for up to 44 days prior to haematology, aerobic metabolic rate and hypoxia tolerance measurements. Hypoxia exposure during incubation (fertilization to 113 days post-fertilization) did not affect the haematology, aerobic performance or hypoxia tolerance of juvenile salmon in later life. Juveniles acclimated to hypoxia increased maximum aerobic metabolic rate and aerobic scope by ~23 and ~52%, respectively, when measured at 50% DO but not at 100% DO. Hypoxia-incubated juveniles also increased haematocrit and haemoglobin concentration but did not affect acute hypoxia tolerance (critical oxygen level and DO at LOE). Thus, while Atlantic salmon possess a considerable capacity to physiologically acclimate to hypoxia by improving aerobic performance in low oxygen conditions, we found no evidence that this capacity is influenced by early-life hypoxia exposure.
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Affiliation(s)
- Andrew T Wood
- Commonwealth Scientific and Industrial Research Organisation, Agriculture and Food, 3-4 Castray Esplanade, Battery Point, Tasmania 7004, Australia
| | - Sarah J Andrewartha
- Tasmanian Institute of Agriculture, University of Tasmania, Private Bag 98, Hobart, 7001, Australia
| | - Nicholas G Elliott
- Institute for Marine and Antarctic Studies, University of Tasmania, 20 Castray Esplanade, Battery Point, Tasmania 7004, Australia
| | - Peter B Frappell
- Institute for Marine and Antarctic Studies, University of Tasmania, 20 Castray Esplanade, Battery Point, Tasmania 7004, Australia
| | - Timothy D Clark
- School of Life and Environmental Sciences, Deakin University, Geelong, Victoria 3216, Australia
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Vimmerstedt JC, Padilla Pérez DJ, Angilletta MJ, VandenBrooks JM. Oxygen supply limits the heat tolerance of avian embryos. Biol Lett 2019; 15:20190566. [PMID: 31744411 DOI: 10.1098/rsbl.2019.0566] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Physiologists have primarily focused on two potential explanations for heat stress in animals-the classic model of molecular stability and an alternative model of oxygen limitation. Although the classic model has widespread support, the oxygen-supply model applies to many aquatic animals and some terrestrial ones. In particular, the embryonic stage of terrestrial animals seems most susceptible to oxygen limitation because embryos acquire oxygen from the atmosphere by diffusion rather than ventilation. We report experiments confirming the two conditions of the oxygen-supply model in Japanese quail embryos, Coturnix coturnix. Hypoxia (12% O2) greatly reduced the chance of survival at 47.5°C, and hyperoxia greatly improved the chance of survival at 48.5°C. This finding expands the scope of the oxygen-supply model to a terrestrial, endothermic species, suggesting that oxygen supply generally limits the heat tolerance of embryos.
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Affiliation(s)
- Jon C Vimmerstedt
- Department of Physiology, College of Graduate Studies, Midwestern University, Glendale, AZ 85308, USA
| | - Dylan J Padilla Pérez
- Department of Ecology and Evolutionary Biology, Federal University of São Paulo (UNIFESP), Diadema Campus, Rua Dr. Artur Riedel, 275, CEP 09972-270 São Paulo, Brazil
| | | | - John M VandenBrooks
- Department of Physiology, College of Graduate Studies, Midwestern University, Glendale, AZ 85308, USA
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