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Wang J, Li M, Zhuo X, Gao X, Ma X, Zhang X. Salinity-dependent mitigation of naphthalene toxicity in migratory Takifugu obscurus juveniles: Implications for survival, oxidative stress, and osmoregulation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 896:165248. [PMID: 37394067 DOI: 10.1016/j.scitotenv.2023.165248] [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: 03/30/2023] [Revised: 06/03/2023] [Accepted: 06/29/2023] [Indexed: 07/04/2023]
Abstract
Naphthalene, an environmental pollutant classified as a polycyclic aromatic hydrocarbon (PAH), can induce toxicity in fish and other aquatic organisms. Through our investigation, we determined how Takifugu obscurus juveniles were affected by naphthalene (0, 2 mg L-1) exposure in terms of oxidative stress biomarkers and Na+/K+-ATPase activity in various tissues (gill, liver, kidney and muscle) under dissimilar salinities (0, 10 psu). Results suggest that naphthalene exposure significantly affects the survival of T. obscurus juveniles and leads to significant changes in the levels of malondialdehyde, superoxide dismutase, catalase, glutathione, and Na+/K+-ATPase activity, which are indicative of oxidative stress and emphasized the risks associated with osmoregulatory function. The higher salinity affected on the noxious effects of naphthalene can be observed, resulting in decreased biomarker levels and increased Na+/K+-ATPase activity. Salinity levels affected the uptake of naphthalene and its impact on different tissues, with high salinity conditions having mitigating effects on oxidative stress and naphthalene uptake in the liver and kidney tissues. Increased Na+/K+-ATPase activity was observed in all tissues treated with 10 psu and 2 mg L-1 naphthalene. Our findings deepen the understanding of T. obscurus juveniles' physiological responses to naphthalene exposure, and highlight the potential mitigating effects of salinity. These insights can inform the development of appropriate conservation and management practices to protect aquatic organisms from susceptibility.
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Affiliation(s)
- Jun Wang
- College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China
| | - Meng Li
- College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China
| | - Xinnan Zhuo
- College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China
| | - Xiaojian Gao
- College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China
| | - Xiaogang Ma
- School of Civil Engineering, North Minzu University, Yinchuan 750030, China
| | - Xiaojun Zhang
- College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China.
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2
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Somo DA, Chu K, Richards JG. Gill surface area allometry does not constrain the body mass scaling of maximum oxygen uptake rate in the tidepool sculpin, Oligocottus maculosus. J Comp Physiol B 2023:10.1007/s00360-023-01490-9. [PMID: 37149515 DOI: 10.1007/s00360-023-01490-9] [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: 07/05/2022] [Revised: 03/03/2023] [Accepted: 04/14/2023] [Indexed: 05/08/2023]
Abstract
The gill oxygen limitation hypothesis (GOLH) suggests that hypometric scaling of metabolic rate in fishes is a consequence of oxygen supply constraints imposed by the mismatched growth rates of gill surface area (a two-dimensional surface) and body mass (a three-dimensional volume). GOLH may, therefore, explain the size-dependent spatial distribution of fish in temperature- and oxygen-variable environments through size-dependent respiratory capacity, but this question is unstudied. We tested GOLH in the tidepool sculpin, Oligocottus maculosus, a species in which body mass decreases with increasing temperature- and oxygen-variability in the intertidal, a pattern consistent with GOLH. We statistically evaluated support for GOLH versus distributed control of [Formula: see text] allometry by comparing scaling coefficients for gill surface area, standard and maximum [Formula: see text] ([Formula: see text],Standard and [Formula: see text],Max, respectively), ventricle mass, hematocrit, and metabolic enzyme activities in white muscle. To empirically evaluate whether there is a proximate constraint on oxygen supply capacity with increasing body mass, we measured [Formula: see text],Max across a range of Po2s from normoxia to Pcrit, calculated the regulation value (R), a measure of oxyregulatory capacity, and analyzed the R-body mass relationship. In contrast with GOLH, gill surface area scaling either matched or was more than sufficient to meet [Formula: see text] demands with increasing body mass and R did not change with body mass. Ventricle mass (b = 1.22) scaled similarly to [Formula: see text],Max (b = 1.18) suggesting a possible role for the heart in the scaling of [Formula: see text],Max. Together our results do not support GOLH as a mechanism structuring the distribution of O. maculosus and suggest distributed control of oxyregulatory capacity.
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Affiliation(s)
- Derek A Somo
- Department of Zoology, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.
| | - Ken Chu
- 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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3
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Somo DA, Chu K, Richards JG. Aerobic scope falls to nil at Pcrit and anaerobic ATP production increases below Pcrit in the tidepool sculpin, Oligocottus maculosus. Biol Lett 2022; 18:20220342. [PMID: 36475421 PMCID: PMC9727657 DOI: 10.1098/rsbl.2022.0342] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The critical oxygen tension of whole-animal oxygen uptake rate, or Pcrit, has historically been defined as the oxygen partial pressure (PO2) at which aerobic scope falls to zero and further declines in PO2 require substrate-level phosphorylation to meet shortfalls in aerobic ATP production, thereby time-limiting survival. Despite the inclusion of aerobic scope and anaerobic ATP production in the definition, little effort has been made to verify that Pcrit measurements, the vast majority of which are obtained using respirometry in resting animals, actually reflect the predictions of zero aerobic scope and a transition to increasing reliance on anaerobic ATP production. To test these predictions, we compared aerobic scope and levels of whole-body lactate at oxygen partial pressures (PO2s) bracketing Pcrit obtained in resting fish during progressive hypoxia in the tidepool sculpin, Oligocottus maculosus. We found that aerobic scope falls to zero at Pcrit and, in resting fish exposed to PO2s < Pcrit, whole-body lactate accumulated pointing to an increased reliance on anaerobic ATP production. These results support the interpretation of Pcrit as a key oxygen threshold at which aerobic scope falls to nil and, below Pcrit, survival is time-limited based on anaerobic metabolic capacity.
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Affiliation(s)
- Derek A. Somo
- Department of Zoology, The University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
| | - Ken Chu
- Department of Zoology, The University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
| | - Jeffrey G. Richards
- Department of Zoology, The University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
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4
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Yin X, Wu J, Liu Y, Chen X, Xie C, Liang Y, Li J, Jiang Z. Accumulation of microplastics in fish guts and gills from a large natural lake: Selective or non-selective? ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 309:119785. [PMID: 35843450 DOI: 10.1016/j.envpol.2022.119785] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 06/24/2022] [Accepted: 07/11/2022] [Indexed: 06/15/2023]
Abstract
In recent years, microplastics (MPs) have become emerging contaminant causing widespread concern about their ecotoxicological effects. However, little is known regarding the accumulation of MPs in different tissues of fishes, especially for freshwater fishes in natural environments. In this study, MPs in guts and gills of 11 fish species from Lake Chao, China were examined to explore the accumulation differences and foraging preferences of MPs. In general, MPs in fish guts varied from 2.85 to 8.38 items/individual, while ranged from 3.06 to 8.90 items/individual in fish gills. In terms of characteristic composition (shape, color, size, and polymer type), our results demonstrate higher occurrence of fibrous, black, small sized (<1 mm), and polypropylene MPs. Meanwhile, MPs concentrations in fish guts differed significantly among various feeding groups, with none significant difference detected in fish gills. In addition, fish guts exhibit more distinct foraging preferences for specific featured MPs in contrast with fish gills. These results indicate selective MPs accumulation in fish guts whereas random MPs accumulation in fish gills. Fish gills, adhering MPs by non-selective water exchange, may be more related to the real-time MPs abundance in water. To some extent, fish gills may be employed as important instruments to reflect MPs contamination in aquatic environments. Influenced by diverse feeding behaviors such as visual cues and sensory systems, MPs accumulation in fish guts reflect intrinsic differences, thus making fish guts sensitive organ in monitoring MPs' ecological risk for their health.
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Affiliation(s)
- Xiaowei Yin
- School of Resources and Environmental Engineering, Anhui University, Hefei, 230601, PR China
| | - Jiajun Wu
- School of Resources and Environmental Engineering, Anhui University, Hefei, 230601, PR China
| | - Yunzhao Liu
- School of Resources and Environmental Engineering, Anhui University, Hefei, 230601, PR China
| | - Xin Chen
- School of Resources and Environmental Engineering, Anhui University, Hefei, 230601, PR China
| | - Chang Xie
- School of Resources and Environmental Engineering, Anhui University, Hefei, 230601, PR China
| | - Yangyang Liang
- Key Laboratory of Freshwater Aquaculture and Enhancement of Anhui Province, Fisheries Research Institute, Anhui Academy of Agricultural Sciences, Hefei, 230001, PR China
| | - Jing Li
- Key Laboratory of Freshwater Aquaculture and Enhancement of Anhui Province, Fisheries Research Institute, Anhui Academy of Agricultural Sciences, Hefei, 230001, PR China
| | - Zhongguan Jiang
- School of Resources and Environmental Engineering, Anhui University, Hefei, 230601, PR China; Anhui Province Key Laboratory of Wetland Ecosystem Protection and Restoration (Anhui University), Hefei, 230601, PR China; German Centre for Integrative Biodiversity Research (iDiv), Halle-Jena-Leipzig, Puschstrasse 4, Leipzig, 04103, Germany.
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5
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Liu S, Wilson JM, Taylor EB, Richards JG. Freshwater adaptation in prickly sculpin (Pisces: Cottidae): intraspecific comparisons reveal evidence for water pH and Na+ concentration driving diversity in gill H+-ATPase and ionoregulation. J Exp Biol 2022; 225:276687. [PMID: 36062522 DOI: 10.1242/jeb.243500] [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: 09/15/2021] [Accepted: 08/26/2022] [Indexed: 11/20/2022]
Abstract
Phenotypic divergence is a hallmark of adaptive radiation. One example involves differentiation in physiological traits involved in ion regulation among species with contrasting life-styles and living in distinct environments. Differentiation in ion regulation and its ecological implications among populations within species are, however, less well understood. To address this knowledge gap, we collected prickly sculpin (Cottus asper) from distinct habitat types including coastal rivers connected to estuaries, coastal lakes, and interior lakes, all from British Columbia, Canada. We tested for differences in plasma Na+ and Cl-, gill Na+/K+-ATPase and H+-ATPase activities and protein abundance as well as changes in body mass, and arterial blood pH in fish sampled from the field and acclimated to two different freshwater conditions in the laboratory including artificial lake water (ALW) and ion-poor water (IPW). We also tested for associations between environmental water chemistry and the physiological characteristics associated with ion regulation. Transfer to IPW resulted upregulation in gill Na+/K+-ATPase and H+-ATPase activities as well as increases in gill H+-ATPase protein expression level in each habitat compared with the common ALW treatment. Despite the presence of population-within-habitat type differences, significant habitat-type effects were revealed in most of the ion regulation characteristics examined under different acclimation conditions. Significantly lower plasma Cl- was detected in fish from coastal rivers compared to fish from the other two habitat types during the IPW treatment, which was also significantly lower compared with ALW. Similarly, gill Na+/K+-ATPase activity was lower in the coastal river populations in IPW than in fish from coastal and interior lakes, which was not in accordance with the protein expressed in the gill. For gill H+-ATPase, fish from interior lake populations had the highest level of activity across all habitat types under all conditions, which was related to the protein levels in the gill. The activity of gill H+-ATPase was positively correlated with the combined effect of water Na+ and pH under the ALW treatment. Our results suggest that variation in habitat may be an important factor driving differences in gill Na+/K+-ATPase and H+-ATPase activities across populations of C. asper. Further, the combined effect of water Na+ and pH may have played a key role in physiological adaptation in C. asper during post-glacial freshwater colonization and dispersal.
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Affiliation(s)
- Shuang Liu
- Department of Zoology, The University of British Columbia, 6270 University Blvd., Vancouver, BC V6T 1Z4, Canada
| | - Jonathan M Wilson
- Department of Biology, Wilfrid Laurier University, 75 University Ave., Waterloo, ON N2L 3C5, Canada
| | - Eric B Taylor
- Department of Zoology, Biodiversity Research Centre and Beaty Biodiversity Museum, The University of British Columbia, 6270 University Blvd., Vancouver, BC V6T 1Z4, Canada
| | - Jeffrey G Richards
- Department of Zoology, The University of British Columbia, 6270 University Blvd., Vancouver, BC V6T 1Z4, Canada
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6
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Harter TS, Damsgaard C, Regan MD. Linking environmental salinity to respiratory phenotypes and metabolic rate in fishes: a data mining and modelling approach. J Exp Biol 2022; 225:274262. [PMID: 35258603 DOI: 10.1242/jeb.243421] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The gill is the primary site of ionoregulation and gas exchange in adult teleost fishes. However, those characteristics that benefit diffusive gas exchange (large, thin gills) may also enhance the passive equilibration of ions and water that threaten osmotic homeostasis. Our literature review revealed that gill surface area and thickness were similar in freshwater (FW) and seawater (SW) species; however, the diffusive oxygen (O2) conductance (Gd) of the gill was lower in FW species. While a lower Gd may reduce ion losses, it also limits O2 uptake capacity and possibly aerobic performance in situations of high O2 demand (e.g. exercise) or low O2 availability (e.g. environmental hypoxia). We also found that FW fishes had significantly higher haemoglobin (Hb)-O2 binding affinities than SW species, which will increase the O2 diffusion gradient across the gills. Therefore, we hypothesized that the higher Hb-O2 affinity of FW fishes compensates, in part, for their lower Gd. Using a combined literature review and modelling approach, our results show that a higher Hb-O2 affinity in FW fishes increases the flux of O2 across their low-Gd gills. In addition, FW and SW teleosts can achieve similar maximal rates of O2 consumption (ṀO2,max) and hypoxia tolerance (Pcrit) through different combinations of Hb-O2 affinity and Gd. Our combined data identified novel patterns in gill and Hb characteristics between FW and SW fishes and our modelling approach provides mechanistic insight into the relationship between aerobic performance and species distribution ranges, generating novel hypotheses at the intersection of cardiorespiratory and ionoregulatory fish physiology.
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Affiliation(s)
- Till S Harter
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093, USA
| | - Christian Damsgaard
- Zoophysiology, Department of Biology, Aarhus University, 8000 Aarhus, Denmark.,Aarhus Institute of Advanced Studies, Aarhus University, 8000 Aarhus, Denmark
| | - Matthew D Regan
- Département de sciences biologiques, Université de Montréal, Montreal, QC, Canada, H3T 1J4
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7
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Moulton TL, Chapman LJ, Krahe R. Effects of hypoxia on aerobic metabolism and active electrosensory acquisition in the African weakly electric fish Marcusenius victoriae. JOURNAL OF FISH BIOLOGY 2020; 96:496-505. [PMID: 31845335 DOI: 10.1111/jfb.14234] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 12/13/2019] [Indexed: 06/10/2023]
Abstract
Environmental hypoxia has effected numerous and well-documented anatomical, physiological and behavioural adaptations in fishes. Comparatively little is known about hypoxia's impacts on sensing because it is difficult to quantify sensory acquisition in vivo. Weakly electric fishes, however, rely heavily on an easily-measurable sensory modality-active electric sensing-whereby individuals emit and detect electric organ discharges (EODs). In this study, hypoxia tolerance of a mormyrid weakly electric fish, Marcusenius victoriae, was assessed by examining both its metabolic and EOD rates using a critical threshold (pcrit ) paradigm. The routine metabolic rate was 1.42 mg O2 h-1 , and the associated critical oxygen tension was 14.34 mmHg. Routine EOD rate was 5.68 Hz with an associated critical tension of 15.14 mmHg. These metabolic indicators of hypoxia tolerance measured in this study were consistent with those in previous studies on M. victoriae and other weakly electric fishes. Furthermore, our results suggest that some aerobic processes may be reduced in favour of maintaining the EOD rate under extreme hypoxia. These findings underscore the importance of the active electrosensory modality to these hypoxia-tolerant fish.
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Affiliation(s)
- Tyler L Moulton
- Department of Biology, McGill University, Montreal, Quebec, Canada
- Department of Biology, Hamilton College, Clinton, New York, USA
| | - Lauren J Chapman
- Department of Biology, McGill University, Montreal, Quebec, Canada
| | - Rüdiger Krahe
- Department of Biology, McGill University, Montreal, Quebec, Canada
- Institut für Biologie, Humboldt-Universität zu Berlin, Berlin, Germany
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8
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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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9
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Abdel-Tawwab M, Monier MN, Hoseinifar SH, Faggio C. Fish response to hypoxia stress: growth, physiological, and immunological biomarkers. FISH PHYSIOLOGY AND BIOCHEMISTRY 2019; 45:997-1013. [PMID: 30715663 DOI: 10.1007/s10695-019-00614-9] [Citation(s) in RCA: 141] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 01/22/2019] [Indexed: 05/20/2023]
Abstract
Water quality encompasses the water physical, biological, and chemical parameters. It generally affects the fish growth and welfare. Thus, the success of a commercial aquaculture project depends on supplying the optimum water quality for prompt fish growth at the minimum cost of resources. Although the aquaculture environment is a complicated system, depending on various water quality variables, only less of them have a critical role. One of these vital parameters is dissolved oxygen (DO) level, which requires continuous oversight in aquaculture systems. In addition, the processes of natural stream refinement require suitable DO levels in order to extend for aerobic life forms. The depletion of DO concentration (called hypoxia) in pond water causes great stress on fish where DO levels that remain below 1-2 mg/L for a few hours can adversely affect fish growth resulting in fish death. Furthermore, hypoxia has substantial effects on fish physiological and immune responses, making them more susceptible to diseases. Therefore, to avoid disease outbreak in modern aquaculture production systems where fish are intensified and more crowded, increasing attention should be taken into account on DO levels.
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Affiliation(s)
- Mohsen Abdel-Tawwab
- Department of Fish Biology and Ecology, Central Laboratory for Aquaculture Research, Abbassa, Abo-Hammad, Sharqia, Egypt.
| | - Mohamed N Monier
- Department of Fish Biology and Ecology, Central Laboratory for Aquaculture Research, Abbassa, Abo-Hammad, Sharqia, Egypt
| | - Seyed Hossein Hoseinifar
- Department of Fisheries, Faculty of Fisheries and Environmental Sciences, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran
| | - Caterina Faggio
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina, Italy
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10
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Fang Y, Chan VK, Hines CW, Stiller KT, Richards JG, Brauner CJ. The effects of salinity and photoperiod on aerobic scope, hypoxia tolerance and swimming performance of coho salmon (Oncorhynchus kisutch) reared in recirculating aquaculture systems. Comp Biochem Physiol A Mol Integr Physiol 2019; 231:82-90. [DOI: 10.1016/j.cbpa.2019.01.026] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 01/29/2019] [Accepted: 01/29/2019] [Indexed: 10/27/2022]
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11
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Regan MD, Mandic M, Dhillon RS, Lau GY, Farrell AP, Schulte PM, Seibel BA, Speers-Roesch B, Ultsch GR, Richards JG. Don't throw the fish out with the respirometry water. J Exp Biol 2019; 222:222/6/jeb200253. [DOI: 10.1242/jeb.200253] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Matthew D. Regan
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Milica Mandic
- Department of Biology, University of Ottawa, Ottawa, ON, Canada, K1N 6N5
| | - Rashpal S. Dhillon
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Gigi Y. Lau
- Department of Biosciences, University of Oslo, PO Box 1066, Blindern, 0316 Oslo, Norway
| | - Anthony P. Farrell
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
- Faculty of Land and Food Systems, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
| | - Patricia M. Schulte
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
| | - Brad A. Seibel
- College of Marine Science, University of South Florida, St Petersburg, FL 33701, USA
| | - Ben Speers-Roesch
- Department of Biological Sciences, University of New Brunswick-Saint John, PO Box 5050, Saint John, NB, Canada, E2L 4L5
| | - Gordon R. Ultsch
- Department of Biology, University of Florida, Gainesville, FL 32611, USA
| | - Jeffrey G. Richards
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
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12
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Brauner CJ, Shartau RB, Damsgaard C, Esbaugh AJ, Wilson RW, Grosell M. Acid-base physiology and CO2 homeostasis: Regulation and compensation in response to elevated environmental CO2. FISH PHYSIOLOGY 2019. [DOI: 10.1016/bs.fp.2019.08.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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13
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Wood CM. The fallacy of the P crit - are there more useful alternatives? ACTA ACUST UNITED AC 2018; 221:221/22/jeb163717. [PMID: 30420494 DOI: 10.1242/jeb.163717] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
P crit - generally defined as the P O2 below which the animal can no longer maintain a stable rate of O2 consumption (Ṁ O2 ), such that Ṁ O2 becomes dependent upon P O2 - provides a single number into which a vast amount of experimental effort has been invested. Here, with specific reference to water-breathers, I argue that this focus on the P crit is not useful for six reasons: (1) calculation of P crit usually involves selective data editing; (2) the value of P crit depends greatly on the way it is determined; (3) there is no good theoretical justification for the concept; (4) P crit is not the transition point from aerobic to anaerobic metabolism, and it disguises what is really going on; (5) P crit is not a reliable index of hypoxia tolerance; and (6) P crit carries minimal information content. Preferable alternatives are loss of equilibrium (LOE) tests for hypoxia tolerance, and experimental description of full Ṁ O2 versus P O2 profiles accompanied by measurements of ventilation, lactate appearance and metabolic rate by calorimetry. If the goal is to assess the ability of the animal to regulate Ṁ O2 from this profile in a mathematical fashion, promising, more informative alternatives to P crit are the regulation index and Michaelis-Menten or sigmoidal allosteric analyses.
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Affiliation(s)
- Chris M Wood
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada V6T 1Z4 .,Department of Biology, McMaster University, Hamilton, ON, Canada L8S 4K1.,Rosenstiel School of Marine and Atmospheric Science, University of Miami, FL 33149, USA
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14
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Mandic M, Ramon ML, Gerstein AC, Gracey AY, Richards JG. Variable gene transcription underlies phenotypic convergence of hypoxia tolerance in sculpins. BMC Evol Biol 2018; 18:163. [PMID: 30390629 PMCID: PMC6215679 DOI: 10.1186/s12862-018-1275-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 10/18/2018] [Indexed: 01/03/2023] Open
Abstract
Background The degree by which mechanisms underlying phenotypic convergence are similar among taxa depends on the number of evolutionary paths available for selection to act upon. Likelihood of convergence will be influenced by an interplay of factors such as genetic architecture, phylogenetic history and population demography. To determine if there is convergence or divergence in mechanisms underlying phenotypic similarity, we assessed whether gene transcription patterns differed among species with similar levels of hypoxia tolerance. Results Three species of marine fish from the superfamily Cottoidea (smoothhead sculpin [Artedius lateralis], sailfin sculpin [Nautichthys oculofasciatus] and Pacific staghorn sculpin [Leptocottus armatus]), all of which have previously been shown to share the same level of hypoxia tolerance, were exposed to short-(8 h) and longer-term (72 h) hypoxia and mRNA transcripts were assessed using a custom microarray. We examined hypoxia-induced transcription patterns in metabolic and protein production pathways and found that a high proportion of genes associated with these biological processes showed significant differences among the species. Specifically, the data suggest that the smoothhead sculpin, unlike the sailfin sculpin and the Pacific staghorn sculpin, relied on amino acid degradation rather than glycolysis or fatty acid oxidation to generate ATP during hypoxia exposure. There was also variation across the species in the transcription of genes involved in protein production (e.g. mRNA processing and protein translation), such that it increased in the smoothhead sculpin, decreased in the sailfin sculpin and was variable in the Pacific staghorn sculpin. Conclusions Changes in metabolic and protein production pathways are part of the key responses of fishes to exposures to environmental hypoxia. Yet, species with similar overall hypoxia tolerance exhibited different transcriptional responses in these pathways, indicating flexibility and complexity of interactions in the evolution of the mechanisms underlying the hypoxia tolerance phenotype. The variation in the hypoxia-induced transcription of genes across species with similar hypoxia tolerance suggests that similar whole-animal phenotypes can emerge from divergent evolutionary paths that may affect metabolically important functions. Electronic supplementary material The online version of this article (10.1186/s12862-018-1275-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Milica Mandic
- Department of Zoology, University of British Columbia, 6270 University Blvd, Vancouver, BC, V6T 1Z4, Canada. .,Bamfield Marine Sciences Centre, 100 Pachena Dr, Bamfield, BC, V0R 1B0, Canada.
| | - Marina L Ramon
- Department of Biological Sciences, University of Southern California, 3616 Trousdale Parkway, Los Angeles, CA, 90089-0371, USA
| | - Aleeza C Gerstein
- Department of Genetics, Cell Biology and Development, University of Minnesota, 321 Church Street, Minneapolis, MN, 55455, USA
| | - Andrew Y Gracey
- Department of Biological Sciences, University of Southern California, 3616 Trousdale Parkway, Los Angeles, CA, 90089-0371, USA
| | - Jeffrey G Richards
- Department of Zoology, University of British Columbia, 6270 University Blvd, Vancouver, BC, V6T 1Z4, Canada.,Bamfield Marine Sciences Centre, 100 Pachena Dr, Bamfield, BC, V0R 1B0, Canada
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15
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Malakpour Kolbadinezhad S, Coimbra J, Wilson JM. Osmoregulation in the Plotosidae Catfish: Role of the Salt Secreting Dendritic Organ. Front Physiol 2018; 9:761. [PMID: 30018560 PMCID: PMC6037869 DOI: 10.3389/fphys.2018.00761] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 05/30/2018] [Indexed: 01/14/2023] Open
Abstract
Unlike other marine teleosts, the Plotosidae catfishes reportedly have an extra-branchial salt secreting dendritic organ (DO). Salinity acclimation [brackishwater (BW) 3aaa, seawater (SWcontrol) 34aaa, and hypersaline water (HSW) 60aaa] for 14 days was used to investigate the osmoregulatory abilities of Plotosus lineatus through measurements of blood chemistry, muscle water content (MWC), Na+/K+-ATPase (NKA) specific activity and ion transporter expression in gills, DO, kidney and intestine. Ion transporter expression was determined using immunoblotting, immunohistochemistry (IHC) and quantitative polymerase chain reaction (qPCR). HSW elevated mortality, plasma osmolality and ions, and hematocrit, and decreased MWC indicating an osmoregulatory challenge. NKA specific activity and protein levels were significantly higher in DO compared to gill, kidney and intestine at all salinities. NKA specific activity increased in kidney and posterior intestine with HSW but only kidney showed correspondingly higher NKA α-subunit protein levels. Since DO mass was greater in HSW, the total amount of DO NKA activity expressed per gram fish was greater indicating higher overall capacity. Gill NKA and V-ATPase protein levels were greater with HSW acclimation but this was not reflected in NKA activity, mRNA or ionocyte abundance. BW acclimation resulted in lower NKA activity in gill, kidney and DO. Cl- levels were better regulated and the resulting strong ion ratio in BW suggests a metabolic acidosis. Elevated DO heat shock protein 70 levels in HSW fish indicate a cellular stress. Strong NKA and NKCC1 (Na+:K+:2Cl- cotransporter1) co-localization was observed in DO parenchymal cells, which was rare in gill ionocytes. NKCC1 immunoblot expression was only detected in DO, which was highest at HSW. Cystic fibrosis transmembrane regulator Cl- channel (CFTR) localize apically to DO NKA immunoreactive cells. Taken together, the demonstration of high NKA activity in DO coexpressed with NKCC1 and CFTR indicates the presence of the conserved secondary active Cl- secretion mechanism found in other ion transporting epithelia suggesting a convergent evolution with other vertebrate salt secreting organs. However, the significant osmoregulatory challenge of HSW indicates that the DO may be of limited use under more extreme salinity conditions in contrast to the gill based ionoregulatory strategy of marine teleosts.
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Affiliation(s)
- Salman Malakpour Kolbadinezhad
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR/CIMAR), University of Porto, Porto, Portugal.,Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
| | - João Coimbra
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR/CIMAR), University of Porto, Porto, Portugal.,Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Jonathan M Wilson
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR/CIMAR), University of Porto, Porto, Portugal.,Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal.,Department of Biology, Wilfrid Laurier University, Waterloo, ON, Canada
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16
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Saroglia M, Caricato G, Frittella F, Brambilla F, Terova G. Dissolved oxygen regimen (PO2) may affect osmo respiratory compromise in European sea bass (Dicentrarchus labrax, L.). ITALIAN JOURNAL OF ANIMAL SCIENCE 2017. [DOI: 10.4081/ijas.2010.e15] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Marco Saroglia
- Dipartimento di Biotecnologie e Scienze Molecolari. Università dell’Insubria, Varese, Italy
| | - Gaetano Caricato
- Dipartimento di Scienze delle Produzioni Animali. Università della Basilicata, Potenza, Italy
| | - Ferruccio Frittella
- Agenzia Regionale per la Protezione dell’Ambiente della Basilicata, Potenza, Italy
| | - Fabio Brambilla
- Dipartimento di Biotecnologie e Scienze Molecolari. Università dell’Insubria, Varese, Italy
| | - Genciana Terova
- Dipartimento di Biotecnologie e Scienze Molecolari. Università dell’Insubria, Varese, Italy
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17
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McBryan TL, Healy TM, Haakons KL, Schulte PM. Warm acclimation improves hypoxia tolerance in Fundulus heteroclitus. ACTA ACUST UNITED AC 2017; 219:474-84. [PMID: 26888999 DOI: 10.1242/jeb.133413] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Human activities are increasing both the frequency of hypoxic episodes and the mean temperature of aquatic ecosystems, but few studies have considered the possibility that acclimation to one of these stressors could improve the ability to cope with the other stressor. Here, we used Atlantic killifish, Fundulus heteroclitus, to test this hypothesis. Hypoxia tolerance was measured as time to loss of equilibrium in hypoxia (LOEhyp) at 0.4 kPa oxygen. Time to LOEhyp declined from 73.3 ± 6.9 min at 15 °C to 2.6 ± 3.8 min at 23 °C, and at 30 °C no fish could withstand this level of hypoxia. Prior acclimation to warm temperatures significantly increased time to LOEhyp. Hypoxia tolerance of the southern subspecies of killifish, F. heteroclitus heteroclitus, was greater than that of the northern subspecies, F. heteroclitus macrolepidotus, measured both as critical oxygen tension (Pcrit) and as time to LOEhyp. Warm acclimation offset the negative effects of temperature on time to LOEhyp to a similar extent in the two subspecies. Warm acclimation increased total lamellar surface area of the gill in both subspecies as a result of regression of an interlamellar cell mass (ILCM). However, differences in total lamellar surface area could not explain differences in time to LOEhyp between the subspecies, suggesting that the lower time to LOEhyp of northern fish is related to their higher routine metabolic rate. These data suggest that thermal plasticity in gill morphology can improve the capacity of this species to tolerate hypoxia, and shows how existing plasticity may help organisms to cope with the complex interacting stressors that they will encounter with increasing frequency as our climate changes.
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Affiliation(s)
- Tara L McBryan
- Department of Zoology, 6270 University Blvd, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
| | - Timothy M Healy
- Department of Zoology, 6270 University Blvd, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
| | - Kristen L Haakons
- Department of Zoology, 6270 University Blvd, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
| | - Patricia M Schulte
- Department of Zoology, 6270 University Blvd, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
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18
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Air breathing and aquatic gas exchange during hypoxia in armoured catfish. J Comp Physiol B 2016; 187:117-133. [DOI: 10.1007/s00360-016-1024-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 06/23/2016] [Accepted: 07/19/2016] [Indexed: 10/21/2022]
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19
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Rogers NJ, Urbina MA, Reardon EE, McKenzie DJ, Wilson RW. A new analysis of hypoxia tolerance in fishes using a database of critical oxygen level (P crit). CONSERVATION PHYSIOLOGY 2016; 4:cow012. [PMID: 27293760 PMCID: PMC4849809 DOI: 10.1093/conphys/cow012] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 03/17/2016] [Accepted: 03/19/2016] [Indexed: 05/19/2023]
Abstract
Hypoxia is a common occurrence in aquatic habitats, and it is becoming an increasingly frequent and widespread environmental perturbation, primarily as the result of anthropogenic nutrient enrichment and climate change. An in-depth understanding of the hypoxia tolerance of fishes, and how this varies among individuals and species, is required to make accurate predictions of future ecological impacts and to provide better information for conservation and fisheries management. The critical oxygen level (P crit) has been widely used as a quantifiable trait of hypoxia tolerance. It is defined as the oxygen level below which the animal can no longer maintain a stable rate of oxygen uptake (oxyregulate) and uptake becomes dependent on ambient oxygen availability (the animal transitions to oxyconforming). A comprehensive database of P crit values, comprising 331 measurements from 96 published studies, covering 151 fish species from 58 families, provides the most extensive and up-to-date analysis of hypoxia tolerance in teleosts. Methodologies for determining P crit are critically examined to evaluate its usefulness as an indicator of hypoxia tolerance in fishes. Various abiotic and biotic factors that interact with hypoxia are analysed for their effect on P crit, including temperature, CO2, acidification, toxic metals and feeding. Salinity, temperature, body mass and routine metabolic rate were strongly correlated with P crit; 20% of variation in the P crit data set was explained by these four variables. An important methodological issue not previously considered is the inconsistent increase in partial pressure of CO2 within a closed respirometer during the measurement of P crit. Modelling suggests that the final partial pressure of CO2 reached can vary from 650 to 3500 µatm depending on the ambient pH and salinity, with potentially major effects on blood acid-base balance and P crit itself. This database will form part of a widely accessible repository of physiological trait data that will serve as a resource to facilitate future studies of fish ecology, conservation and management.
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Affiliation(s)
- Nicholas J Rogers
- Biosciences, College of Life and Environmental Sciences, Geoffrey Pope Building, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
| | - Mauricio A Urbina
- Biosciences, College of Life and Environmental Sciences, Geoffrey Pope Building, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
| | - Erin E Reardon
- Biosciences, College of Life and Environmental Sciences, Geoffrey Pope Building, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
| | - David J McKenzie
- Centre for Marine Biodiversity Exploitation and Conservation (Marbec), UMR 9190 CNRS-Université Montpellier-Ifremer-IRD, Université Montpellier, Place Eugène Bataillon, Montpellier cedex 5 34095, France
| | - Rod W Wilson
- Biosciences, College of Life and Environmental Sciences, Geoffrey Pope Building, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
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20
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Borowiec BG, Crans KD, Khajali F, Pranckevicius NA, Young A, Scott GR. Interspecific and environment-induced variation in hypoxia tolerance in sunfish. Comp Biochem Physiol A Mol Integr Physiol 2016; 198:59-71. [PMID: 27085372 DOI: 10.1016/j.cbpa.2016.04.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 04/01/2016] [Accepted: 04/09/2016] [Indexed: 11/18/2022]
Abstract
Hypoxia tolerance is a plastic trait, and can vary between species. We compared hypoxia tolerance (hypoxic loss of equilibrium, LOE, and critical O2 tension, Pcrit) and traits that dictate O2 transport and metabolism in pumpkinseed (Lepomis gibbosus), bluegill (L. macrochirus), and the naturally occurring hybrid in different acclimation environments (wild versus lab-acclimated fish) and at different temperatures. Wild fish generally had lower Pcrit and lower PO2 at LOE in progressive hypoxia than lab-acclimated fish, but time to LOE in sustained hypoxia (PO2 of 2kPa) did not vary between environments. Wild fish also had greater gill surface area and higher haematocrit, suggesting that increased O2 transport capacity underlies the environmental variation in Pcrit. Metabolic (lactate dehydrogenase, LDH; pyruvate kinase, PK; citrate synthase; cytochrome c oxidase) and antioxidant (catalase and superoxide dismutase) enzyme activities varied appreciably between environments. Wild fish had higher protein contents across tissues and higher activities of LDH in heart, PK in brain, and catalase in brain, liver, and skeletal muscle. Otherwise, wild fish had lower activities for most enzymes. Warming temperature from 15 to 25°C increased O2 consumption rate, Pcrit, PO2 at LOE, and haemoglobin-O2 affinity, and decreased time to LOE, but pumpkinseed had ≥2-fold longer time to LOE than bluegill and hybrids across this temperature range. This was associated with higher LDH activities in the heart and muscle, and lower or similar antioxidant enzyme activities in several tissues. However, the greater hypoxia tolerance of pumpkinseed collapsed at 28°C, demonstrating that the interactive effects of hypoxia and warming temperature can differ between species. Overall, distinct mechanisms appear to underpin interspecific and environment-induced variation in hypoxia tolerance in sunfish.
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Affiliation(s)
- Brittney G Borowiec
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada.
| | - Kyle D Crans
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada
| | - Fariborz Khajali
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada; Department of Animal Science, Shahrekord University, Shahrekord, Chahar Mahal Va Bakhtiari, Iran
| | - Nicole A Pranckevicius
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada
| | - Alexander Young
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada
| | - Graham R Scott
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada
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21
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Esbaugh AJ, Ern R, Nordi WM, Johnson AS. Respiratory plasticity is insufficient to alleviate blood acid–base disturbances after acclimation to ocean acidification in the estuarine red drum, Sciaenops ocellatus. J Comp Physiol B 2015; 186:97-109. [DOI: 10.1007/s00360-015-0940-6] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Revised: 09/23/2015] [Accepted: 10/04/2015] [Indexed: 01/10/2023]
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22
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Heinrich DDU, Rummer JL, Morash AJ, Watson SA, Simpfendorfer CA, Heupel MR, Munday PL. A product of its environment: the epaulette shark (Hemiscyllium ocellatum) exhibits physiological tolerance to elevated environmental CO2. CONSERVATION PHYSIOLOGY 2014; 2:cou047. [PMID: 27293668 PMCID: PMC4806737 DOI: 10.1093/conphys/cou047] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 09/14/2014] [Accepted: 09/14/2014] [Indexed: 05/27/2023]
Abstract
Ocean acidification, resulting from increasing anthropogenic CO2 emissions, is predicted to affect the physiological performance of many marine species. Recent studies have shown substantial reductions in aerobic performance in some teleost fish species, but no change or even enhanced performance in others. Notably lacking, however, are studies on the effects of near-future CO2 conditions on larger meso and apex predators, such as elasmobranchs. The epaulette shark (Hemiscyllium ocellatum) lives on shallow coral reef flats and in lagoons, where it may frequently encounter short-term periods of environmental hypoxia and elevated CO2, especially during nocturnal low tides. Indeed, H. ocellatum is remarkably tolerant to short periods (hours) of hypoxia, and possibly hypercapnia, but nothing is known about its response to prolonged exposure. We exposed H. ocellatum individuals to control (390 µatm) or one of two near-future CO2 treatments (600 or 880 µatm) for a minimum of 60 days and then measured key aspects of their respiratory physiology, namely the resting oxygen consumption rate, which is used to estimate resting metabolic rate, and critical oxygen tension, a proxy for hypoxia sensitivity. Neither of these respiratory attributes was affected by the long-term exposure to elevated CO2. Furthermore, there was no change in citrate synthase activity, a cellular indicator of aerobic energy production. Plasma bicarbonate concentrations were significantly elevated in sharks exposed to 600 and 880 µatm CO2 treatments, indicating that acidosis was probably prevented by regulatory changes in acid-base relevant ions. Epaulette sharks may therefore possess adaptations that confer tolerance to CO2 levels projected to occur in the ocean by the end of this century. It remains uncertain whether other elasmobranchs, especially pelagic species that do not experience such diurnal fluctuations in their environment, will be equally tolerant.
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Affiliation(s)
- Dennis D. U. Heinrich
- School of Marine and Tropical Biology, James Cook University, Townsville, Queensland 4811, Australia
| | - Jodie L. Rummer
- ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland 4811, Australia
| | - Andrea J. Morash
- University of Tasmania, Institute for Marine and Antarctic Studies (IMAS), Sandy Bay, Tasmania 7001, Australia
| | - Sue-Ann Watson
- School of Marine and Tropical Biology, James Cook University, Townsville, Queensland 4811, Australia
- ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland 4811, Australia
| | - Colin A. Simpfendorfer
- Centre for Sustainable Tropical Fisheries and Aquaculture, School of Earth and Environmental Science, James Cook University, Townsville, Queensland 4811, Australia
| | - Michelle R. Heupel
- Centre for Sustainable Tropical Fisheries and Aquaculture, School of Earth and Environmental Science, James Cook University, Townsville, Queensland 4811, Australia
- Australian Institute of Marine Science, Townsville, Queensland 4810, Australia
| | - Philip L. Munday
- School of Marine and Tropical Biology, James Cook University, Townsville, Queensland 4811, Australia
- ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland 4811, Australia
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Turko AJ, Robertson CE, Bianchini K, Freeman M, Wright PA. The amphibious fish Kryptolebias marmoratus uses different strategies to maintain oxygen delivery during aquatic hypoxia and air exposure. ACTA ACUST UNITED AC 2014; 217:3988-95. [PMID: 25267849 DOI: 10.1242/jeb.110601] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Despite the abundance of oxygen in atmospheric air relative to water, the initial loss of respiratory surface area and accumulation of carbon dioxide in the blood of amphibious fishes during emersion may result in hypoxemia. Given that the ability to respond to low oxygen conditions predates the vertebrate invasion of land, we hypothesized that amphibious fishes maintain O2 uptake and transport while emersed by mounting a co-opted hypoxia response. We acclimated the amphibious fish Kryptolebias marmoratus, which are able to remain active for weeks in both air and water, for 7 days to normoxic brackish water (15‰, ~21kPa O2; control), aquatic hypoxia (~3.6kPa), normoxic air (~21 kPa) or aerial hypoxia (~13.6kPa). Angiogenesis in the skin and bucco-opercular chamber was pronounced in air- versus water-acclimated fish, but not in response to hypoxia. Aquatic hypoxia increased the O2-carrying capacity of blood via a large (40%) increase in red blood cell density and a small increase in the affinity of hemoglobin for O2 (P50 decreased 11%). In contrast, air exposure increased the hemoglobin O2 affinity (decreased P50) by 25% without affecting the number of red blood cells. Acclimation to aerial hypoxia both increased the O2-carrying capacity and decreased the hemoglobin O2 affinity. These results suggest that O2 transport is regulated both by O2 availability and also, independently, by air exposure. The ability of the hematological system to respond to air exposure independent of O2 availability may allow extant amphibious fishes, and may also have allowed primitive tetrapods to cope with the complex challenges of aerial respiration during the invasion of land.
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Affiliation(s)
- Andy J Turko
- Department of Integrative Biology, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Cayleih E Robertson
- Department of Integrative Biology, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Kristin Bianchini
- Department of Integrative Biology, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Megan Freeman
- Department of Integrative Biology, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Patricia A Wright
- Department of Integrative Biology, University of Guelph, Guelph, ON N1G 2W1, Canada
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24
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Robertson LM, Wood CM. Measuring gill paracellular permeability with polyethelene glycol-4000 in freely swimming trout: proof of principle. J Exp Biol 2014; 217:1425-9. [DOI: 10.1242/jeb.099879] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Summary
The influence of swimming activity on gill paracellular permeability has not been measured previously in fishes. We critically assessed the use of [3H]PEG-4000 for this purpose, a substance which is also a classic marker for extracellular fluid volume, glomerular filtration rate, and drinking rate. Tests (8h) on resting freshwater trout showed that when measuring [3H]PEG-4000 clearance from the plasma in the efflux direction, correction for a large excretion via glomerular filtration was essential, necessitating urinary catheterization. When measuring [3H]PEG-4000 clearance from the water in the influx direction, correction for a significant uptake by drinking was essential, necessitating terminal gut removal, whereas glomerular filtration losses were minimal. After correction for these alternate routes of loss and uptake, [3H]PEG-4000 clearance rates by efflux from the plasma and by influx from the water were identical, showing that gill paracellular permeability is not rectified, and can be measured in either direction. The influx technique with terminal gut removal was used to assess gill paracellular permeability in trout without urinary catheters freely swimming at 1.2 body lengths per sec for 8h. Branchial [3H]PEG-4000 clearance rate (by influx from the water) increased significantly by about 80% in accord with a similar measured increase in O2 consumption rate. Thus in trout, gill paracellular permeability does increase during exercise, in accord with the traditional concept of the osmorespiratory compromise.
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25
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Tripathi RK, Mohindra V, Singh A, Kumar R, Mishra RM, Jena JK. Physiological responses to acute experimental hypoxia in the air-breathing Indian catfish, Clarias batrachus (Linnaeus, 1758). J Biosci 2013; 38:373-83. [PMID: 23660672 DOI: 10.1007/s12038-013-9304-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
With an aim to study the mechanism of adaptation to acute hypoxic periods by hypoxia-tolerant catfish, Clarias batrachus, the mass-specific metabolic rate (VO2) along with its hematological parameters, metabolic response and antioxidant enzyme activities were studied. During progressive hypoxia, C. batrachus was found to be an oxyconformer and showed a steady decline in its aquatic oxygen consumption rate. When C. batrachus was exposed for different periods at experimental hypoxia level (0.98 +/- 0.1 mg/L, DO), hemoglobin and hematocrit concentrations were increased, along with decrease in mean cellular hemoglobin concentration, which reflected a physiological adaptation to enhance oxygen transport capacity. Significant increase in serum glucose and lactate concentration as well as lactate dehydrogenase activity was observed. Antioxidant enzymes were found to operate independently of one another, while total glutathione concentration was unaffected in any of the tissues across treatments. These observations suggested that hypoxia resulted in the development of oxidative stress and C. batrachus was able to respond through increase in the oxygen carrying capacity, metabolic depression and efficient antioxidant defense system to survive periods of acute hypoxia.
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Affiliation(s)
- Ratnesh Kumar Tripathi
- National Bureau of Fish Genetic Resources, Canal Ring Road, P.O. Dilkusha, Lucknow 226 001
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26
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Collins GM, Clark TD, Rummer JL, Carton AG. Hypoxia tolerance is conserved across genetically distinct sub-populations of an iconic, tropical Australian teleost (Lates calcarifer). CONSERVATION PHYSIOLOGY 2013; 1:cot029. [PMID: 27293613 PMCID: PMC4806625 DOI: 10.1093/conphys/cot029] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 09/10/2013] [Accepted: 09/10/2013] [Indexed: 05/16/2023]
Abstract
Tropical coastal systems are particularly prone to periods of environmental hypoxia, which can result from organismal respiration as well as thermal stratification, and may be further exacerbated by anthropogenic disturbances. In this study, we used five genetically distinct sub-populations of Australian barramundi (Lates calcarifer) to examine the extent of intraspecific variability in hypoxia tolerance. Fish were maintained at two temperatures (26 or 36°C), representing the seasonal thermal range for this species across its tropical distribution in Australia. All fish maintained a constant oxygen consumption rate [Formula: see text] as air saturation of the water decreased from 100% down to a critical oxygen saturation ([O2]crit) of 15.44 ± 3.20 and 21.07 ± 3.92% (means ± SD) at 26 and 36°C, respectively. Mean [O2]crit, used as a performance measure of hypoxia tolerance, did not differ between sub-populations. No differences were found for resting [Formula: see text] between sub-populations at 26°C, but modest differences were detected between two sub-populations at 36°C (3.36 ± 0.62 and 2.83 ± 0.27 mg O2 kg(-1) min(-1) for Gladstone and Broome sub-populations, respectively). Resting [Formula: see text] was lower for sub-populations at 26°C (1.46 ± 0.26 mg O2 kg(-1) min(-1)) than at 36°C (3.10 ± 0.43 mg O2 kg(-1) min(-1)), with a temperature coefficient (Q 10) of 2.12 ± 0.30. We conclude that both hypoxia tolerance and resting [Formula: see text] are conserved across the distribution of barramundi in Australia, which reflects the capacity of this species to cope in environments with large fluctuations in both temperature and dissolved oxygen.
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Affiliation(s)
- Geoffrey M. Collins
- Centre for Sustainable Tropical Fisheries and Aquaculture & School of Marine and Tropical Biology, James Cook University, Townsville, QLD 4811, Australia
- AIMS@JCU Collaborative Research Program, Townsville, QLD 4810, Australia
- Corresponding author: Centre for Sustainable Tropical Fisheries and Aquaculture & School of Marine and Tropical Biology, James Cook University, Townsville, QLD 4811, Australia. Tel: +61 747 815585.
| | - Timothy D. Clark
- AIMS@JCU Collaborative Research Program, Townsville, QLD 4810, Australia
- Australian Institute of Marine Science, PMB 3, Townsville MC, QLD 4810, Australia
| | - Jodie L. Rummer
- ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD 4811, Australia
| | - Alexander G. Carton
- Centre for Sustainable Tropical Fisheries and Aquaculture & School of Marine and Tropical Biology, James Cook University, Townsville, QLD 4811, Australia
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Speers-Roesch B, Richards JG, Brauner CJ, Farrell AP, Hickey AJR, Wang YS, Renshaw GMC. Hypoxia tolerance in elasmobranchs. I. Critical oxygen tension as a measure of blood oxygen transport during hypoxia exposure. ACTA ACUST UNITED AC 2012; 215:93-102. [PMID: 22162857 DOI: 10.1242/jeb.059642] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The critical O(2) tension of whole-animal O(2) consumption rate (M(O2)), or P(crit), is the water P(O2) (Pw(O(2))) at which an animal transitions from an oxyregulator to an oxyconformer. Although P(crit) is a popular measure of hypoxia tolerance in fishes because it reflects the capacity for O(2) uptake from the environment at low Pw(O(2)), little is known about the interrelationships between P(crit) and blood O(2) transport characteristics and increased use of anaerobic metabolism during hypoxia exposure in fishes, especially elasmobranchs. We addressed this knowledge gap using progressive hypoxia exposures of two elasmobranch species with differing hypoxia tolerance. The P(crit) of the hypoxia-tolerant epaulette shark (Hemiscyllium ocellatum, 5.10±0.37 kPa) was significantly lower than that of the comparatively hypoxia-sensitive shovelnose ray (Aptychotrema rostrata, 7.23±0.40 kPa). Plasma [lactate] was elevated above normoxic values at around P(crit) in epaulette sharks, but increased relative to normoxic values at Pw(O(2)) below P(crit) in shovelnose rays, providing equivocal support for the hypothesis that P(crit) is associated with increased anaerobic metabolism. The M(O2), arterial P(O2) and arterial blood O(2) content (Ca(O(2))) were similar between the two species under normoxia and decreased in both species with progressive hypoxia, but as Pw(O(2)) declined, epaulette sharks had a consistently higher M(O2) and Ca(O(2)) than shovelnose rays, probably due to their significantly greater in vivo haemoglobin (Hb)-O(2) binding affinity (in vivo Hb-O(2) P(50)=4.27±0.57 kPa for epaulette sharks vs 6.35±0.34 kPa for shovelnose rays). However, at Pw(O(2)) values representing the same percentage of each species' P(crit) (up to ∼175% of P(crit)), Hb-O(2) saturation and Ca(O(2)) were similar between species. These data support the hypothesis that Hb-O(2) P(50) is an important determinant of P(crit) and suggest that P(crit) can predict Hb-O(2) saturation and Ca(O(2)) during hypoxia exposure, with a lower P(crit) being associated with greater O(2) supply at a given Pw(O(2)) and consequently better hypoxia tolerance. Thus, P(crit) is a valuable predictor of environmental hypoxia tolerance and hypoxia exposures standardized at a given percentage of P(crit) will yield comparable levels of arterial hypoxaemia, facilitating cross-species comparisons of responses to hypoxia.
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Affiliation(s)
- Ben Speers-Roesch
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada, V6T 1Z4.
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Dalziel AC, Ou M, Schulte PM. Mechanisms underlying parallel reductions in aerobic capacity in non-migratory threespine stickleback (Gasterosteus aculeatus) populations. J Exp Biol 2012; 215:746-59. [DOI: 10.1242/jeb.065425] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
SUMMARY
Non-migratory, stream-resident populations of threespine stickleback, Gasterosteus aculeatus, have a lower maximum oxygen consumption (ṀO2,max) than ancestral migratory marine populations. Here, we examined laboratory-bred stream-resident and marine crosses from two locations (West and Bonsall Creeks) to determine which steps in the oxygen transport and utilization cascade evolved in conjunction with, and thus have the potential to contribute to, these differences in ṀO2,max. We found that West Creek stream-resident fish have larger muscle fibres (not measured in Bonsall fish), Bonsall Creek stream-resident fish have smaller ventricles, and both stream-resident populations have evolved smaller pectoral adductor and abductor muscles. However, many steps of the oxygen cascade did not evolve in stream-resident populations (gill surface area, hematocrit, mean cellular hemoglobin content and the activities of mitochondrial enzymes per gram ventricle and pectoral muscle), arguing against symmorphosis. We also studied F1 hybrids to determine which traits in the oxygen cascade have a genetic architecture similar to that of ṀO2,max. In West Creek, ṀO2,max, abductor and adductor size all showed dominance of marine alleles, whereas in Bonsall Creek, ṀO2,max and ventricle mass showed dominance of stream-resident alleles. We also found genetically based differences among marine populations in hematocrit, ventricle mass, pectoral muscle mass and pectoral muscle pyruvate kinase activity. Overall, reductions in pectoral muscle mass evolved in conjunction with reductions in ṀO2,max in both stream-resident populations, but the specific steps in the oxygen cascade that have a genetic basis similar to that of ṀO2,max, and are thus predicted to have the largest impact on ṀO2,max, differ among populations.
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Affiliation(s)
- Anne C. Dalziel
- Biodiversity Research Center and Department of Zoology, 6270 University Blvd, University of British Columbia, Vancouver, BC, CanadaV6T 1Z4
| | - Michelle Ou
- Biodiversity Research Center and Department of Zoology, 6270 University Blvd, University of British Columbia, Vancouver, BC, CanadaV6T 1Z4
| | - Patricia M. Schulte
- Biodiversity Research Center and Department of Zoology, 6270 University Blvd, University of British Columbia, Vancouver, BC, CanadaV6T 1Z4
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29
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Euryhalinity in An Evolutionary Context. ACTA ACUST UNITED AC 2012. [DOI: 10.1016/b978-0-12-396951-4.00010-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Perry SF, Ellis K, Russell J, Bernier NJ, Montpetit C. Effects of chronic dietary salt loading on the renin angiotensin and adrenergic systems of rainbow trout (Oncorhynchus mykiss). Am J Physiol Regul Integr Comp Physiol 2011; 301:R811-21. [PMID: 21697522 DOI: 10.1152/ajpregu.00244.2011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Previous studies have demonstrated that chronic dietary salt loading causes hypertension and a decreased sensitivity of the systemic vasculature to α-adrenergic stimulation and other hypertensive stimuli (e.g. hypercapnia) in rainbow trout (Oncorhynchus mykiss). This reduced sensitivity to hypertensive stimuli is consistent with a possible blunting of homeostatic responses normally aimed at raising blood pressure. To test this idea, we examined the consequences of long-term salt feeding and the associated hypertension on the interactive capacities of the renin angiotensin system (RAS) and adrenergic systems to elevate blood pressure in trout. Secretion of catecholamines in response to a range of doses of homologous ANG II in vivo and in situ (using a perfused posterior cardinal vein preparation) was reduced in the salt-fed fish. The reduced sensitivity to ANG II could not be explained by alterations in stored catecholamine (adrenaline or noradrenaline) levels or the general responsiveness of the chromaffin cells to depolarizing stimuli (60 mmol/l KCl). Despite the decreased responsiveness of the chromaffin cells to ANG II, plasma catecholamines were increased to a greater extent in the salt-fed fish during acute hypoxia (a condition that activates the RAS). Interestingly, the pressor effects of ANG II in vivo were actually heightened in the salt-fed fish. The increased pressor response to exogenous ANG II was likely attributable to its direct interaction with vascular ANG II receptors because the effect persisted even after blockade of α-adrenergic receptors. Treating fish with the vascular smooth muscle relaxant papaverine caused similar reductions in blood pressure and increases in plasma ANG II levels regardless of diet. Similarly, inhibition of angiotensin converting enzyme with lisinopril reduced blood pressure equally in control and salt-fed fish. These results indicate that, while long-term dietary salt loading blunts the response of trout chromaffin cells to ANG II, the RAS itself appears to be unaffected. Indeed, the capacity of ANG II to elevate blood pressure is not compromised nor do fish exhibit a reduced capacity to mount an acute humoral adrenergic stress response during acute hypoxia.
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Affiliation(s)
- Steve F Perry
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada.
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Tzaneva V, Bailey S, Perry SF. The interactive effects of hypoxemia, hyperoxia, and temperature on the gill morphology of goldfish (Carassius auratus). Am J Physiol Regul Integr Comp Physiol 2011; 300:R1344-51. [DOI: 10.1152/ajpregu.00530.2010] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Acclimation of crucian carp and goldfish to temperatures below 15°C causes covering of the gill lamellae by a mass of cells termed the interlamellar cell mass (ILCM). Here we explore the cues underlying gill remodeling (removal or growth of an ILCM) and specifically test the hypotheses that 1) depletion of internal O2 stores in the absence of any change in external O2 status can trigger the removal of the ILCM in goldfish acclimated to 7°C, 2) exposing fish acclimated to 25°C to an abundance of O2 (hyperoxia) can reverse the gill remodeling (i.e., cause the covering of lamellae by an expansion of the ILCM), and 3) neuroepithelial cells (NECs) are involved in signaling the shedding of the ILCM. Hypoxemia induced by phenylhydrazine (anemia) or 5% CO caused a decrease in the ILCM from 80% to 23% and 35%, respectively. Hyperoxia exposure at 25°C caused an increase to 67% of total ILCM and a smaller decrease in the size of the ILCM when fish were transferred from 7 to 25°C. Daily sodium cyanide injections were used to stimulate NECs; this treatment led to a significant decrease in the ILCM. Thus, the three major conclusions of this study are 1) that gill remodeling can occur during periods of internal hypoxemia, 2) that O2 supply and demand may be a significant driving force shaping gill remodeling in goldfish, and 3) the NECs may play a role in triggering the shedding of the ILCM during hypoxia.
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Affiliation(s)
- Velislava Tzaneva
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
| | - Shawn Bailey
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
| | - Steve F. Perry
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
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Matey V, Iftikar FI, De Boeck G, Scott GR, Sloman KA, Almeida-Val VM, Val AL, Wood CM. Gill morphology and acute hypoxia: responses of mitochondria-rich, pavement, and mucous cells in the Amazonian oscar (Astronotus ocellatus) and the rainbow trout (Oncorhynchus mykiss), two species with very different approaches to the osmo-respiratory compromise. CAN J ZOOL 2011. [DOI: 10.1139/z11-002] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The hypoxia-intolerant rainbow trout ( Oncorhynchus mykiss (Walbaum, 1792)) exhibits increased branchial ion permeability and Na+ influx during acute exposure to moderate hypoxia (Po2 = 80 torr; 1 torr = 133.3224 Pa), manifesting the usual trade-off between gas exchange and electrolyte conservation. In contrast, the hypoxia-tolerant oscar ( Astronotus ocellatus (Agassiz, 1831)) is unusual in exhibiting decreased branchial ion permeability to ions and Na+ influx during acute exposure to severe hypoxia (Po2 = 10–20 torr). These different physiological approaches to the osmo-respiratory compromise correlate with rapid, oppositely directed changes in gill morphology. In oscar, pavement cells (PVCs) expanded, partially covering neighboring mitochondria-rich cells (MRCs), which were recessed and reduced in size. Those remaining open were transformed from “shallow-basin” to “deep-hole” forms with smaller openings, deeper apical crypts, and smaller numbers of subapical microvesicles, changes that were largely reversed during normoxic recovery. In contrast, moderate hypoxia caused outward bulging of MRCs in rainbow trout with increases in size, surface exposure, and number of subapical microvesicles, accompanied by PVC retraction. These changes were partially reversed during normoxic recovery. In both rainbow trout and oscar, hypoxia caused discharge of mucus from enlarged mucous cells (MCs). Rapid, divergent morphological changes play an important role in explaining two very different physiological approaches to the osmo-respiratory compromise.
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Affiliation(s)
- Victoria Matey
- Department of Biology, Center for Inland Waters, San Diego State University, San Diego, CA 92182-4614, USA
| | - Fathima I. Iftikar
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - Gudrun De Boeck
- Department of Biology, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium
| | - Graham R. Scott
- Department of Zoology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Katherine A. Sloman
- School of Sciences, University of West of Scotland, Paisley, Scotland, PA1 2BE, UK
| | - Vera M.F. Almeida-Val
- Laboratory of Ecophysiology and Molecular Evolution, Instituto Nacional de Pesquisas da Amazônia (INPA), Manaus, Brazil
| | - Adalberto L. Val
- Laboratory of Ecophysiology and Molecular Evolution, Instituto Nacional de Pesquisas da Amazônia (INPA), Manaus, Brazil
| | - Chris M. Wood
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada
- Division of Marine Biology and Fisheries, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL 33149, USA
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Speers-Roesch B, Sandblom E, Lau GY, Farrell AP, Richards JG. Effects of environmental hypoxia on cardiac energy metabolism and performance in tilapia. Am J Physiol Regul Integr Comp Physiol 2009; 298:R104-19. [PMID: 19864337 DOI: 10.1152/ajpregu.00418.2009] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The ability of an animal to depress ATP turnover while maintaining metabolic energy balance is important for survival during hypoxia. In the present study, we investigated the responses of cardiac energy metabolism and performance in the hypoxia-tolerant tilapia (Oreochromis hybrid sp.) during exposure to environmental hypoxia. Exposure to graded hypoxia (> or =92% to 2.5% air saturation over 3.6 +/- 0.2 h) followed by exposure to 5% air saturation for 8 h caused a depression of whole animal oxygen consumption rate that was accompanied by parallel decreases in heart rate, cardiac output, and cardiac power output (CPO, analogous to ATP demand of the heart). These cardiac parameters remained depressed by 50-60% compared with normoxic values throughout the 8-h exposure. During a 24-h exposure to 5% air saturation, cardiac ATP concentration was unchanged compared with normoxia and anaerobic glycolysis contributed to ATP supply as evidenced by considerable accumulation of lactate in the heart and plasma. Reductions in the provision of aerobic substrates were apparent from a large and rapid (in <1 h) decrease in plasma nonesterified fatty acids concentration and a modest decrease in activity of pyruvate dehydrogenase. Depression of cardiac ATP demand via bradycardia and an associated decrease in CPO appears to be an integral component of hypoxia-induced metabolic rate depression in tilapia and likely contributes to hypoxic survival.
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Affiliation(s)
- Ben Speers-Roesch
- Dept. of Zoology, Univ. of British Columbia, 6270 Univ. Blvd., Vancouver, BC, Canada V6T 1Z4.
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Wood CM, Iftikar FI, Scott GR, De Boeck G, Sloman KA, Matey V, Valdez Domingos FX, Duarte RM, Almeida-Val VMF, Val AL. Regulation of gill transcellular permeability and renal function during acute hypoxia in the Amazonian oscar (Astronotus ocellatus): new angles to the osmorespiratory compromise. J Exp Biol 2009; 212:1949-64. [DOI: 10.1242/jeb.028464] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
Earlier studies demonstrated that oscars, endemic to ion-poor Amazonian waters, are extremely hypoxia tolerant, and exhibit a marked reduction in active unidirectional Na+ uptake rate (measured directly) but unchanged net Na+ balance during acute exposure to low PO2, indicating a comparable reduction in whole body Na+ efflux rate. However, branchial O2 transfer factor does not fall. The present study focused on the nature of the efflux reduction in the face of maintained gill O2 permeability. Direct measurements of 22Na appearance in the water from bladder-catheterized fish confirmed a rapid 55% fall in unidirectional Na+ efflux rate across the gills upon acute exposure to hypoxia(PO2=10–20 torr; 1 torr=133.3 Pa), which was quickly reversed upon return to normoxia. An exchange diffusion mechanism for Na+ is not present, so the reduction in efflux was not directly linked to the reduction in Na+ influx. A quickly developing bradycardia occurred during hypoxia. Transepithelial potential, which was sensitive to water [Ca2+], became markedly less negative during hypoxia and was restored upon return to normoxia. Ammonia excretion, net K+ loss rates, and 3H2O exchange rates(diffusive water efflux rates) across the gills fell by 55–75% during hypoxia, with recovery during normoxia. Osmotic permeability to water also declined, but the fall (30%) was less than that in diffusive water permeability (70%). In total, these observations indicate a reduction in gill transcellular permeability during hypoxia, a conclusion supported by unchanged branchial efflux rates of the paracellular marker [3H]PEG-4000 during hypoxia and normoxic recovery. At the kidney, glomerular filtration rate, urine flow rate, and tubular Na+ reabsorption rate fell in parallel by 70% during hypoxia, facilitating additional reductions in costs and in urinary Na+, K+ and ammonia excretion rates. Scanning electron microscopy of the gill epithelium revealed no remodelling at a macro-level, but pronounced changes in surface morphology. Under normoxia,mitochondria-rich cells were exposed only through small apical crypts, and these decreased in number by 47% and in individual area by 65% during 3 h hypoxia. We suggest that a rapid closure of transcellular channels, perhaps effected by pavement cell coverage of the crypts, allows conservation of ions and reduction of ionoregulatory costs without compromise of O2exchange capacity during acute hypoxia, a response very different from the traditional osmorespiratory compromise.
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Affiliation(s)
- Chris M. Wood
- Department of Biology, McMaster University, Hamilton, Ontario, Canada, L8S 4K1
- Division of Marine Biology and Fisheries, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL 33149, USA
| | - Fathima I. Iftikar
- Department of Biology, McMaster University, Hamilton, Ontario, Canada, L8S 4K1
| | - Graham R. Scott
- Department of Zoology, University of British Columbia, Vancouver, Canada, V6T 1Z4
| | - Gudrun De Boeck
- Department of Biology, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium
| | | | - Victoria Matey
- Department of Biology, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182, USA
| | - Fabiola X. Valdez Domingos
- Laboratory of Ecophysiology and Molecular Evolution, Instituto Nacional de Pesquisas da Amazônia (INPA), Manaus, Brazil
| | - Rafael Mendonça Duarte
- Laboratory of Ecophysiology and Molecular Evolution, Instituto Nacional de Pesquisas da Amazônia (INPA), Manaus, Brazil
| | - Vera M. F. Almeida-Val
- Laboratory of Ecophysiology and Molecular Evolution, Instituto Nacional de Pesquisas da Amazônia (INPA), Manaus, Brazil
| | - Adalberto L. Val
- Laboratory of Ecophysiology and Molecular Evolution, Instituto Nacional de Pesquisas da Amazônia (INPA), Manaus, Brazil
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Mandic M, Todgham AE, Richards JG. Mechanisms and evolution of hypoxia tolerance in fish. Proc Biol Sci 2009; 276:735-44. [PMID: 18996831 DOI: 10.1098/rspb.2008.1235] [Citation(s) in RCA: 169] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The ability of an organism to acquire O(2) from its environment is key to survival and can play an important role in dictating a species' ecological distribution. This study is the first, to our knowledge, to show a tight, phylogenetically independent correlation between hypoxia tolerance, traits involved in dictating O(2) extraction capacity and the distribution of a group of closely related fish species, sculpins from the family Cottidae, along the nearshore marine environment. Sculpins with higher hypoxia tolerance, measured as low critical O(2) tensions (P(crit)), inhabit the O2 variable intertidal zones, while species with lower hypoxia tolerance inhabit the more O(2) stable subtidal zone or freshwater. Hypoxia tolerance is phylogenetically independently associated with an enhanced O(2) extraction capacity, with three principal components accounting for 75 per cent of the variation in P(crit): routine O(2) consumption rate; mass-specific gill surface area; and whole blood haemoglobin (Hb)- O(2)-binding affinity (P(50)). Variation in whole blood Hb-O(2)P(50) is strongly correlated with the intrinsic O(2)-binding properties of the purified Hb while the differences in the concentration of the allosteric Hb modulators, ATP and GTP, provide a Hb system with substantial plasticity for survival in a highly O(2) variable environment.
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Affiliation(s)
- Milica Mandic
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
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Richards JG, Sardella BA, Schulte PM. Regulation of pyruvate dehydrogenase in the common killifish, Fundulus heteroclitus, during hypoxia exposure. Am J Physiol Regul Integr Comp Physiol 2008; 295:R979-90. [PMID: 18579651 DOI: 10.1152/ajpregu.00192.2008] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We examined the metabolic responses of the hypoxia-tolerant killifish (Fundulus heteroclitus) to 15 h of severe hypoxia and recovery with emphasis on muscle substrate usage and the regulation of the mitochondrial protein pyruvate dehydrogenase (PDH), which controls carbohydrate oxidation. Hypoxia survival involved a transient activation of substrate-level phosphorylation in muscle (decreases in [creatine phospate] and increases in [lactate]) during which time mechanisms to reduce overall ATP consumption were initiated. This metabolic transition did not affect total cellular [ATP], but had an impact on cellular energy status as indicated by large decreases in [ATP]/[ADP(free)] and [ATP]/[AMP(free)] and a significant loss of phosphorylation potential and Gibbs free energy of ATP hydrolysis (DeltafG'). The activity of PDH was rapidly (within 3 h) decreased by approximately 50% upon hypoxia exposure and remained depressed relative to normoxic samples throughout. Inactivation of PDH was primarily mediated via posttranslational modification following the accumulation of acetyl-CoA and subsequent activation of pyruvate dehydrogenase kinase (PDK). Estimated changes in cytoplasmic and mitochondrial [NAD(+)]/[NADH] did not parallel one another, suggesting the mitochondrial NADH shuttles do not function during hypoxia exposure. Large increases in the expression of PDK (PDK isoform 2) were consistent with decreased PDH activity; however, these changes in mRNA were not associated with changes in total PDK-2 protein content assessed using mammalian antibodies. No other changes in the expression of other known hypoxia-responsive genes (e.g., lactate dehydrogenase-A or -B) were observed in either muscle or liver.
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Affiliation(s)
- Jeffrey G Richards
- Dept. of Zoology, The Univ. of British Columbia, 6270 Univ. Blvd., Vancouver, BC, Canada V6T 1Z4.
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