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Takei Y. The digestive tract as an essential organ for water acquisition in marine teleosts: lessons from euryhaline eels. ZOOLOGICAL LETTERS 2021; 7:10. [PMID: 34154668 PMCID: PMC8215749 DOI: 10.1186/s40851-021-00175-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 04/16/2021] [Indexed: 05/17/2023]
Abstract
Adaptation to a hypertonic marine environment is one of the major topics in animal physiology research. Marine teleosts lose water osmotically from the gills and compensate for this loss by drinking surrounding seawater and absorbing water from the intestine. This situation is in contrast to that in mammals, which experience a net osmotic loss of water after drinking seawater. Water absorption in fishes is made possible by (1) removal of monovalent ions (desalinization) by the esophagus, (2) removal of divalent ions as carbonate (Mg/CaCO3) precipitates promoted by HCO3- secretion, and (3) facilitation of NaCl and water absorption from diluted seawater by the intestine using a suite of unique transporters. As a result, 70-85% of ingested seawater is absorbed during its passage through the digestive tract. Thus, the digestive tract is an essential organ for marine teleost survival in the hypertonic seawater environment. The eel is a species that has been frequently used for osmoregulation research in laboratories worldwide. The eel possesses many advantages as an experimental animal for osmoregulation studies, one of which is its outstanding euryhalinity, which enables researchers to examine changes in the structure and function of the digestive tract after direct transfer from freshwater to seawater. In recent years, the molecular mechanisms of ion and water transport across epithelial cells (the transcellular route) and through tight junctions (the paracellular route) have been elucidated for the esophagus and intestine. Thanks to the rapid progress in analytical methods for genome databases on teleosts, including the eel, the molecular identities of transporters, channels, pumps and junctional proteins have been clarified at the isoform level. As 10 y have passed since the previous reviews on this subject, it seems relevant and timely to summarize recent progress in research on the molecular mechanisms of water and ion transport in the digestive tract in eels and to compare the mechanisms with those of other teleosts and mammals from comparative and evolutionary viewpoints. We also propose future directions for this research field to achieve integrative understanding of the role of the digestive tract in adaptation to seawater with regard to pathways/mechanisms including the paracellular route, divalent ion absorption, metabolon formation and cellular trafficking of transporters. Notably, some of these have already attracted practical attention in laboratories.
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Affiliation(s)
- Yoshio Takei
- Laboratory of Physiology, Department of Marine Bioscience, Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8564, Japan.
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Ruiz-Jarabo I, Gregório SF, Alves A, Mancera JM, Fuentes J. Ocean acidification compromises energy management in Sparus aurata (Pisces: Teleostei). Comp Biochem Physiol A Mol Integr Physiol 2021; 256:110911. [PMID: 33647459 DOI: 10.1016/j.cbpa.2021.110911] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 01/18/2021] [Accepted: 01/18/2021] [Indexed: 11/19/2022]
Abstract
The effects of ocean acidification mediated by an increase in water pCO2 levels on marine organisms are currently under debate. Elevated CO2 concentrations in the seawater induce several physiological responses in teleost fish, including acid-base imbalances and osmoregulatory changes. However, the consequences of CO2 levels enhancement on energy metabolism are mostly unknown. Here we show that 5 weeks of exposure to hypercapnia (950 and 1800 μatm CO2) altered intermediary metabolism of gilthead seabream (Sparus aurata) compared to fish acclimated to current ocean values (440 μatm CO2). We found that seabream compromises its physiological acid-base balance with increasing water CO2 levels and the subsequent acidification. Intestinal regions (anterior, mid, and rectum) engaged in maintaining this balance are thus altered, as seen for Na+/K+-ATPase and the vacuolar-type H+-ATPase activities. Moreover, liver and muscle counteracted these effects by increasing catabolic routes e.g., glycogenolysis, glycolysis, amino acid turnover, and lipid catabolism, and plasma energy metabolites were altered. Our results demonstrate how a relatively short period of 5 weeks of water hypercapnia is likely to disrupt the acid-base balance, osmoregulatory capacity and intermediary metabolism in S. aurata. However, long-term studies are necessary to fully understand the consequences of ocean acidification on growth and other energy-demanding activities, such as reproduction.
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Affiliation(s)
- I Ruiz-Jarabo
- Centre of Marine Sciences (CCMar), University do Algarve, Campus de Gambelas, Faro, Portugal; Department of Biology, Faculty of Marine and Environmental Sciences, Instituto Universitario de Investigación Marina (INMAR), Universidad de Cádiz, Campus de Excelencia Internacional del Mar (CEI·MAR), Puerto Real, Cádiz, Spain; Department of Animal Physiology, Faculty of Biological Sciences, University Complutense, Madrid, Spain.
| | - S F Gregório
- Centre of Marine Sciences (CCMar), University do Algarve, Campus de Gambelas, Faro, Portugal
| | - A Alves
- Centre of Marine Sciences (CCMar), University do Algarve, Campus de Gambelas, Faro, Portugal
| | - J M Mancera
- Department of Biology, Faculty of Marine and Environmental Sciences, Instituto Universitario de Investigación Marina (INMAR), Universidad de Cádiz, Campus de Excelencia Internacional del Mar (CEI·MAR), Puerto Real, Cádiz, Spain
| | - J Fuentes
- Centre of Marine Sciences (CCMar), University do Algarve, Campus de Gambelas, Faro, Portugal.
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Alves A, Gregório SF, Ruiz-Jarabo I, Fuentes J. Intestinal response to ocean acidification in the European sea bass (Dicentrarchus labrax). Comp Biochem Physiol A Mol Integr Physiol 2020; 250:110789. [DOI: 10.1016/j.cbpa.2020.110789] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 08/06/2020] [Accepted: 08/06/2020] [Indexed: 11/30/2022]
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Strader ME, Wong JM, Hofmann GE. Ocean acidification promotes broad transcriptomic responses in marine metazoans: a literature survey. Front Zool 2020; 17:7. [PMID: 32095155 PMCID: PMC7027112 DOI: 10.1186/s12983-020-0350-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 01/06/2020] [Indexed: 01/16/2023] Open
Abstract
For nearly a decade, the metazoan-focused research community has explored the impacts of ocean acidification (OA) on marine animals, noting that changes in ocean chemistry can impact calcification, metabolism, acid-base regulation, stress response and behavior in organisms that hold high ecological and economic value. Because OA interacts with several key physiological processes in marine organisms, transcriptomics has become a widely-used method to characterize whole organism responses on a molecular level as well as inform mechanisms that explain changes in phenotypes observed in response to OA. In the past decade, there has been a notable rise in studies that examine transcriptomic responses to OA in marine metazoans, and here we attempt to summarize key findings across these studies. We find that organisms vary dramatically in their transcriptomic responses to pH although common patterns are often observed, including shifts in acid-base ion regulation, metabolic processes, calcification and stress response mechanisms. We also see a rise in transcriptomic studies examining organismal response to OA in a multi-stressor context, often reporting synergistic effects of OA and temperature. In addition, there is an increase in studies that use transcriptomics to examine the evolutionary potential of organisms to adapt to OA conditions in the future through population and transgenerational experiments. Overall, the literature reveals complex organismal responses to OA, in which some organisms will face more dramatic consequences than others. This will have wide-reaching impacts on ocean communities and ecosystems as a whole.
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Affiliation(s)
- Marie E Strader
- 1Department of Ecology, Evolution and Marine Biology, University of California Santa Barbara, Santa Barbara, CA 93106 USA.,2Department of Biological Sciences, Auburn University, Auburn, AL 36849 USA
| | - Juliet M Wong
- 1Department of Ecology, Evolution and Marine Biology, University of California Santa Barbara, Santa Barbara, CA 93106 USA.,3Present address: Department of Biological Sciences, Florida International University, North Miami, FL 33181 USA
| | - Gretchen E Hofmann
- 1Department of Ecology, Evolution and Marine Biology, University of California Santa Barbara, Santa Barbara, CA 93106 USA
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Transcriptome profiling reveals exposure to predicted end-of-century ocean acidification as a stealth stressor for Atlantic cod larvae. Sci Rep 2019; 9:16908. [PMID: 31729401 PMCID: PMC6858462 DOI: 10.1038/s41598-019-52628-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 10/17/2019] [Indexed: 01/12/2023] Open
Abstract
Ocean acidification (OA), a direct consequence of increasing atmospheric CO2 concentration dissolving in ocean waters, is impacting many fish species. Little is known about the molecular mechanisms underlying the observed physiological impacts in fish. We used RNAseq to characterize the transcriptome of 3 different larval stages of Atlantic cod (Gadus morhua) exposed to simulated OA at levels (1179 µatm CO2) representing end-of-century predictions compared to controls (503 µatm CO2), which were shown to induce tissue damage and elevated mortality in G. morhua. Only few genes were differentially expressed in 6 and 13 days-post-hatching (dph) (3 and 16 genes, respectively), during a period when maximal mortality as a response to elevated pCO2 occurred. At 36 dph, 1413 genes were differentially expressed, most likely caused by developmental asynchrony between the treatment groups, with individuals under OA growing faster. A target gene analysis revealed only few genes of the universal and well-defined cellular stress response to be differentially expressed. We thus suggest that predicted ocean acidification levels constitute a "stealth stress" for early Atlantic cod larvae, with a rapid breakdown of cellular homeostasis leading to organismal death that was missed even with an 8-fold replication implemented in this study.
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Effect of salinity and temperature on the expression of genes involved in branchial ion transport processes in European sea bass. J Therm Biol 2019; 85:102422. [DOI: 10.1016/j.jtherbio.2019.102422] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 09/05/2019] [Accepted: 09/17/2019] [Indexed: 12/24/2022]
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Havenhand JN, Filipsson HL, Niiranen S, Troell M, Crépin AS, Jagers S, Langlet D, Matti S, Turner D, Winder M, de Wit P, Anderson LG. Ecological and functional consequences of coastal ocean acidification: Perspectives from the Baltic-Skagerrak System. AMBIO 2019; 48:831-854. [PMID: 30506502 PMCID: PMC6541583 DOI: 10.1007/s13280-018-1110-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 05/21/2018] [Accepted: 10/03/2018] [Indexed: 05/03/2023]
Abstract
Ocean temperatures are rising; species are shifting poleward, and pH is falling (ocean acidification, OA). We summarise current understanding of OA in the brackish Baltic-Skagerrak System, focussing on the direct, indirect and interactive effects of OA with other anthropogenic drivers on marine biogeochemistry, organisms and ecosystems. Substantial recent advances reveal a pattern of stronger responses (positive or negative) of species than ecosystems, more positive responses at lower trophic levels and strong indirect interactions in food-webs. Common emergent themes were as follows: OA drives planktonic systems toward the microbial loop, reducing energy transfer to zooplankton and fish; and nutrient/food availability ameliorates negative impacts of OA. We identify several key areas for further research, notably the need for OA-relevant biogeochemical and ecosystem models, and understanding the ecological and evolutionary capacity of Baltic-Skagerrak ecosystems to respond to OA and other anthropogenic drivers.
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Affiliation(s)
- Jonathan N. Havenhand
- Department of Marine Sciences, Tjärnö Marine Laboratory, University of Gothenburg, Strömstad, 45296 Gothenburg, Sweden
| | | | - Susa Niiranen
- Stockholm Resilience Centre, Stockholm University, Kräftriket 2B, 10691 Stockholm, Sweden
| | - Max Troell
- Stockholm Resilience Centre, Stockholm University, Kräftriket 2B, 10691 Stockholm, Sweden
- Beijer Institute of Ecological Economics, Royal Swedish Academy of Science, Lilla Frescativägen 4, 10405 Stockholm, Sweden
| | - Anne-Sophie Crépin
- Beijer Institute of Ecological Economics, Royal Swedish Academy of Science, Lilla Frescativägen 4, 10405 Stockholm, Sweden
| | - Sverker Jagers
- Department of Political Sciences, University of Gothenburg, Box 711, Sprängkullsgatan 19, 40530 Gothenburg, Sweden
| | - David Langlet
- Department of Law, University of Gothenburg, Box 650, 40530 Gothenburg, Sweden
| | - Simon Matti
- Department of Political Sciences, Luleå University of Technology, 97187 Luleå, Sweden
| | - David Turner
- Department of Marine Sciences, University of Gothenburg, Box 461, 40530 Gothenburg, Sweden
| | - Monika Winder
- Department of Ecology, Environment and Plant Sciences, Stockholm University, 10691 Stockholm, Sweden
| | - Pierre de Wit
- Department of Marine Sciences, Tjärnö Marine Laboratory, University of Gothenburg, Strömstad, 45296 Gothenburg, Sweden
| | - Leif G. Anderson
- Department of Marine Sciences, University of Gothenburg, Box 461, 40530 Gothenburg, Sweden
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Sui Y, Liu Y, Zhao X, Dupont S, Hu M, Wu F, Huang X, Li J, Lu W, Wang Y. Defense Responses to Short-term Hypoxia and Seawater Acidification in the Thick Shell Mussel Mytilus coruscus. Front Physiol 2017; 8:145. [PMID: 28337153 PMCID: PMC5343010 DOI: 10.3389/fphys.2017.00145] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2016] [Accepted: 02/24/2017] [Indexed: 12/26/2022] Open
Abstract
The rising anthropogenic atmospheric CO2 results in the reduction of seawater pH, namely ocean acidification (OA). In East China Sea, the largest coastal hypoxic zone was observed in the world. This region is also strongly impacted by ocean acidification as receiving much nutrient from Changjiang and Qiantangjiang, and organisms can experience great short-term natural variability of DO and pH in this area. In order to evaluate the defense responses of marine mussels under this scenario, the thick shell mussel Mytilus coruscus were exposed to three pH/pCO2 levels (7.3/2800 μatm, 7.7/1020 μatm, 8.1/376 μatm) at two dissolved oxygen concentrations (DO, 2.0, 6.0 mg L−1) for 72 h. Results showed that byssus thread parameters, such as the number, diameter, attachment strength and plaque area were reduced by low DO, and shell-closing strength was significantly weaker under both hypoxia and low pH conditions. Expression patterns of genes related to mussel byssus protein (MBP) were affected by hypoxia. Generally, hypoxia reduced MBP1 and MBP7 expressions, but increased MBP13 expression. In conclusion, both hypoxia and low pH induced negative effects on mussel defense responses, with hypoxia being the main driver of change. In addition, significant interactive effects between pH and DO were observed on shell-closing strength. Therefore, the adverse effects induced by hypoxia on the defense of mussels may be aggravated by low pH in the natural environments.
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Affiliation(s)
- Yanming Sui
- Department of Biology, College of Fisheries and Life Science, Shanghai Ocean UniversityShanghai, China; Key Laboratory of East China Sea and Oceanic Fishery Resources Exploitation, Ministry of Agriculture of China, East China Sea Fisheries Research Institute, Chinese Academy of Fisheries SciencesShanghai, China
| | - Yimeng Liu
- Department of Biology, College of Fisheries and Life Science, Shanghai Ocean UniversityShanghai, China; Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of EducationShanghai, China
| | - Xin Zhao
- Key Laboratory of East China Sea and Oceanic Fishery Resources Exploitation, Ministry of Agriculture of China, East China Sea Fisheries Research Institute, Chinese Academy of Fisheries Sciences Shanghai, China
| | - Sam Dupont
- Department of Biological and Environmental Sciences, Sven Lovén Centre for Marine Sciences, University of Gothenburg Fiskebäckskil, Sweden
| | - Menghong Hu
- Department of Biology, College of Fisheries and Life Science, Shanghai Ocean UniversityShanghai, China; Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of EducationShanghai, China
| | - Fangli Wu
- Department of Biology, College of Fisheries and Life Science, Shanghai Ocean University Shanghai, China
| | - Xizhi Huang
- Department of Biology, College of Fisheries and Life Science, Shanghai Ocean University Shanghai, China
| | - Jiale Li
- Department of Biology, College of Fisheries and Life Science, Shanghai Ocean UniversityShanghai, China; Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of EducationShanghai, China
| | - Weiqun Lu
- Department of Biology, College of Fisheries and Life Science, Shanghai Ocean UniversityShanghai, China; Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of EducationShanghai, China
| | - Youji Wang
- Department of Biology, College of Fisheries and Life Science, Shanghai Ocean UniversityShanghai, China; Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of EducationShanghai, China
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Heuer RM, Grosell M. Elevated CO 2 increases energetic cost and ion movement in the marine fish intestine. Sci Rep 2016; 6:34480. [PMID: 27682149 PMCID: PMC5041088 DOI: 10.1038/srep34480] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 09/14/2016] [Indexed: 11/09/2022] Open
Abstract
Energetic costs associated with ion and acid-base regulation in response to ocean acidification have been predicted to decrease the energy available to fish for basic life processes. However, the low cost of ion regulation (6-15% of standard metabolic rate) and inherent variation associated with whole-animal metabolic rate measurements have made it difficult to consistently demonstrate such a cost. Here we aimed to gain resolution in assessing the energetic demand associated with acid-base regulation by examining ion movement and O2 consumption rates of isolated intestinal tissue from Gulf toadfish acclimated to control or 1900 μatm CO2 (projected for year 2300). The active marine fish intestine absorbs ions from ingested seawater in exchange for HCO3- to maintain water balance. We demonstrate that CO2 exposure causes a 13% increase of intestinal HCO3- secretion that the animal does not appear to regulate. Isolated tissue from CO2-exposed toadfish also exhibited an 8% higher O2 consumption rate than tissue from controls. These findings show that compensation for CO2 leads to a seemingly maladaptive persistent base (HCO3-) loss that incurs an energetic expense at the tissue level. Sustained increases to baseline metabolic rate could lead to energetic reallocations away from other life processes at the whole-animal level.
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Affiliation(s)
- Rachael M Heuer
- University of Miami- Rosenstiel School of Marine and Atmospheric Science, 4600 Rickenbacker Causeway, Miami, FL 33149, USA
| | - Martin Grosell
- University of Miami- Rosenstiel School of Marine and Atmospheric Science, 4600 Rickenbacker Causeway, Miami, FL 33149, USA
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