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Kovac A, Goss GG. Cellular mechanisms of ion and acid-base regulation in teleost gill ionocytes. J Comp Physiol B 2024:10.1007/s00360-024-01560-6. [PMID: 38761226 DOI: 10.1007/s00360-024-01560-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Revised: 04/16/2024] [Accepted: 04/27/2024] [Indexed: 05/20/2024]
Abstract
The mechanism(s) of sodium, chloride and pH regulation in teleost fishes has been the subject of intense interest for researchers over the past 100 years. The primary organ responsible for ionoregulatory homeostasis is the gill, and more specifically, gill ionocytes. Building on the theoretical and experimental research of the past, recent advances in molecular and cellular techniques in the past two decades have allowed for substantial advances in our understanding of mechanisms involved. With an increased diversity of teleost species and environmental conditions being investigated, it has become apparent that there are multiple strategies and mechanisms employed to achieve ion and acid-base homeostasis. This review will cover the historical developments in our understanding of the teleost fish gill, highlight some of the recent advances and conflicting information in our understanding of ionocyte function, and serve to identify areas that require further investigation to improve our understanding of complex cellular and molecular machineries involved in iono- and acid-base regulation.
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Affiliation(s)
- Anthony Kovac
- Department of Biological Sciences, University of Alberta, Edmonton, AB, T6G 2E9, Canada
| | - Greg G Goss
- Department of Biological Sciences, University of Alberta, Edmonton, AB, T6G 2E9, Canada.
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Retention of ion channel genes expression increases Japanese medaka survival during seawater reacclimation. J Comp Physiol B 2023; 193:81-93. [PMID: 36264377 DOI: 10.1007/s00360-022-01465-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/11/2022] [Indexed: 01/24/2023]
Abstract
Euryhaline teleosts exhibit varying acclimability to survive in environments that alternate between being hypotonic and hypertonic. Such ability is conferred by ion channels expressed by ionocytes, the ion-regulating cells in the gills or skin. However, switching between environments is physiologically challenging, because most channels can only perform unidirectional ion transportation. Coordination between acute responses, such as gene expression, and long-term responses, such as cell differentiation, is believed to strongly facilitate adaptability. Moreover, the pre-acclimation to half seawater salinity can improve the survivability of Japanese medaka (Oryzias latipes) during direct transfer to seawater; here, the ionocytes preserve hypertonic acclimability while performing hypotonic functions. Whether acclimability can be similarly induced in a closed species and their corresponding responses in terms of ion channel expression remain unclear. In the present study, Japanese medaka pre-acclimated in brackish water were noted to have higher survival rates while retaining higher expression of the three ion channel genes ATP1a1a.1, ATP1b1b, and SLC12a2a. This retention was maintained up to 2 weeks after the fish were transferred back into freshwater. Notably, this induced acclimability was not found in its close kin, Indian medaka (Oryzias dancena), the natural habitat of which is brackish water. In conclusion, Japanese medaka surpassed Indian medaka in seawater acclimability after experiencing exposure to brackish water, and this ability coincided with seawater-retention gene expression.
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Zhu S, Yan X, Shen C, Wu L, Tang D, Wang Y, Wang Z. Transcriptome analysis of the gills of Eriocheir sinensis provide novel insights into the molecular mechanisms of the pH stress response. Gene 2022; 833:146588. [PMID: 35598683 DOI: 10.1016/j.gene.2022.146588] [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: 10/06/2021] [Revised: 04/26/2022] [Accepted: 05/16/2022] [Indexed: 11/04/2022]
Abstract
Eriocheir sinensis is an important economic species in China, which is easily affected by pH changes. However, the molecular mechanism of the pH stress response in E. sinensis is still unclear. Therefore, this study aimed to examine the molecular response mechanism of E. sinensis based on pH variation surveillance, histopathological evaluation and transcriptomic analyses. Firstly, pH variation surveillance showed that E. sinensis could actively regulate the pH of its environment. Meanwhile, the histopathological evaluation suggested that pH stress seriously damaged the gills, especially at high pH. Finally, transcriptome analysis showed that the expression of genes related to ion transport, immune stress, and energy metabolism significantly changed. Many genes played an important role in the pH response of E. sinensis, such as carbonic anhydrase (CA), mitochondrial proton/calcium exchanger protein (LETM1), recombinant sodium/hydrogen exchanger 3 (SLC9A3/NHE3), heat shock protein 90 alpha family class a member (HSP90A), alkylglycerone phosphate synthase (AGPS), succinate-CoA ligase ADP-forming subunit beta (LSC2), and superoxide dismutase (SOD). Our study revealed the molecular response mechanism of E. sinensis in response to pH stress, thus providing a basis for further research on the molecular mechanism of response to pH stress in aquatic animals.
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Affiliation(s)
- Shang Zhu
- Jiangsu Key Laboratory for Bioresources of Saline Soils, Jiangsu Synthetic Innovation Center for Coastal Bio-agriculture, Jiangsu Provincial Key Laboratory of Coastal Wetland Bioresources and Environmental Protection, School of Wetlands, Yancheng Teachers University, Yancheng 224001, Jiangsu Province, China
| | - Xinyao Yan
- Jiangsu Key Laboratory for Bioresources of Saline Soils, Jiangsu Synthetic Innovation Center for Coastal Bio-agriculture, Jiangsu Provincial Key Laboratory of Coastal Wetland Bioresources and Environmental Protection, School of Wetlands, Yancheng Teachers University, Yancheng 224001, Jiangsu Province, China
| | - Chenchen Shen
- Jiangsu Key Laboratory for Bioresources of Saline Soils, Jiangsu Synthetic Innovation Center for Coastal Bio-agriculture, Jiangsu Provincial Key Laboratory of Coastal Wetland Bioresources and Environmental Protection, School of Wetlands, Yancheng Teachers University, Yancheng 224001, Jiangsu Province, China
| | - Lv Wu
- Jiangsu Key Laboratory for Bioresources of Saline Soils, Jiangsu Synthetic Innovation Center for Coastal Bio-agriculture, Jiangsu Provincial Key Laboratory of Coastal Wetland Bioresources and Environmental Protection, School of Wetlands, Yancheng Teachers University, Yancheng 224001, Jiangsu Province, China
| | - Dan Tang
- Jiangsu Key Laboratory for Bioresources of Saline Soils, Jiangsu Synthetic Innovation Center for Coastal Bio-agriculture, Jiangsu Provincial Key Laboratory of Coastal Wetland Bioresources and Environmental Protection, School of Wetlands, Yancheng Teachers University, Yancheng 224001, Jiangsu Province, China; College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211800, Jiangsu Province, China
| | - Yue Wang
- Jiangsu Key Laboratory for Bioresources of Saline Soils, Jiangsu Synthetic Innovation Center for Coastal Bio-agriculture, Jiangsu Provincial Key Laboratory of Coastal Wetland Bioresources and Environmental Protection, School of Wetlands, Yancheng Teachers University, Yancheng 224001, Jiangsu Province, China
| | - Zhengfei Wang
- Jiangsu Key Laboratory for Bioresources of Saline Soils, Jiangsu Synthetic Innovation Center for Coastal Bio-agriculture, Jiangsu Provincial Key Laboratory of Coastal Wetland Bioresources and Environmental Protection, School of Wetlands, Yancheng Teachers University, Yancheng 224001, Jiangsu Province, China.
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Genome-wide identification of the NHE gene family in Coilia nasus and its response to salinity challenge and ammonia stress. BMC Genomics 2022; 23:526. [PMID: 35858854 PMCID: PMC9297642 DOI: 10.1186/s12864-022-08761-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 07/13/2022] [Indexed: 11/25/2022] Open
Abstract
Background In aquatic environments, pH, salinity, and ammonia concentration are extremely important for aquatic animals. NHE is a two-way ion exchange carrier protein, which can transport Na+ into cells and exchange out H+, and also plays key roles in regulating intracellular pH, osmotic pressure, and ammonia concentration. Results In the present study, ten NHEs, the entire NHE gene family, were identified from Coilia nasus genome and systemically analyzed via phylogenetic, structural, and synteny analysis. Different expression patterns of C. nasus NHEs in multiple tissues indicated that expression profiles of NHE genes displayed tissue-specific. Expression patterns of C. nasus NHEs were related to ammonia excretion during multiple embryonic development stages. To explore the potential functions on salinity challenge and ammonia stress, expression levels of ten NHEs were detected in C. nasus gills under hypotonic stress, hypertonic stress, and ammonia stress. Expression levels of all NHEs were upregulated during hypotonic stress, while they were downregulated during hypertonic stress. NHE2 and NHE3 displayed higher expression levels in C. nasus larvae and juvenile gills under ammonia stress. Conclusions Our study revealed that NHE genes played distinct roles in embryonic development, salinity stress, and ammonia exposure. Syntenic analysis showed significant difference between stenohaline fish and euryhaline fishes. Our findings will provide insight into effects of C. nasus NHE gene family on ion transport and ammonia tolerance and be beneficial for healthy aquaculture of C. nasus. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-022-08761-9.
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Shih SW, Yan JJ, Tsou YL, Lu SW, Wang MC, Chou MY, Hwang PP. In Vivo Functional Assay in Fish Gills: Exploring Branchial Acid-Excreting Mechanisms in Zebrafish. Int J Mol Sci 2022; 23:ijms23084419. [PMID: 35457237 PMCID: PMC9031880 DOI: 10.3390/ijms23084419] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 04/13/2022] [Accepted: 04/14/2022] [Indexed: 02/06/2023] Open
Abstract
Molecular and physiological analyses in ionoregulatory organs (e.g., adult gills and embryonic skin) are essential for studying fish ion regulation. Recent progress in the molecular physiology of fish ion regulation was mostly obtained in embryonic skin; however, studies of ion regulation in adult gills are still elusive and limited because there are no direct methods for in vivo functional assays in the gills. The present study applied the scanning ion-selective electrode technique (SIET) in adult gills to investigate branchial H+-excreting functions in vivo. We removed the opercula from zebrafish and then performed long-term acid acclimation experiments. The results of Western blot and immunofluorescence showed that the protein expression of H+-ATPase (HA) and the number of H+-ATPase-rich ionocytes were increased under acidic situations. The SIET results proved that the H+ excretion capacity is indeed enhanced in the gills acclimated to acidic water. In addition, both HA and Na+/H+ exchanger (Nhe) inhibitors suppressed the branchial H+ excretion capacity, suggesting that H+ is excreted in association with HA and Nhe in zebrafish gills. These results demonstrate that SIET is effective for in vivo detection in fish gills, representing a breakthrough approach for studying the molecular physiology of fish ion regulation.
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Affiliation(s)
- Shang-Wu Shih
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 11529, Taiwan; (S.-W.S.); (J.-J.Y.); (Y.-L.T.); (S.-W.L.); (M.-C.W.)
- Department of Life Science, National Taiwan University, Taipei 10617, Taiwan;
| | - Jia-Jiun Yan
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 11529, Taiwan; (S.-W.S.); (J.-J.Y.); (Y.-L.T.); (S.-W.L.); (M.-C.W.)
| | - Yi-Ling Tsou
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 11529, Taiwan; (S.-W.S.); (J.-J.Y.); (Y.-L.T.); (S.-W.L.); (M.-C.W.)
| | - Shao-Wei Lu
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 11529, Taiwan; (S.-W.S.); (J.-J.Y.); (Y.-L.T.); (S.-W.L.); (M.-C.W.)
| | - Min-Chen Wang
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 11529, Taiwan; (S.-W.S.); (J.-J.Y.); (Y.-L.T.); (S.-W.L.); (M.-C.W.)
| | - Ming-Yi Chou
- Department of Life Science, National Taiwan University, Taipei 10617, Taiwan;
| | - Pung-Pung Hwang
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 11529, Taiwan; (S.-W.S.); (J.-J.Y.); (Y.-L.T.); (S.-W.L.); (M.-C.W.)
- Department of Life Science, National Taiwan University, Taipei 10617, Taiwan;
- Correspondence:
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Liu ST, Horng JL, Lin LY. Role of the Basolateral Na+/H+ Exchanger-2 (NHE2) in Ionocytes of Seawater- Acclimated Medaka (Oryzias latipes). Front Physiol 2022; 13:870967. [PMID: 35399277 PMCID: PMC8987715 DOI: 10.3389/fphys.2022.870967] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 02/28/2022] [Indexed: 12/03/2022] Open
Abstract
Ionocytes in the skin and gills of seawater (SW) fishes are responsible for acid-base regulation and salt secretion. Na+/H+ exchangers (NHEs) are considered the major acid (H+)-secreting transporters in ionocytes of SW fishes. However, the subcellular localization and function of a specific NHE isoform (NHE2) have never clearly been revealed. In this study, we cloned and sequenced NHE2 from an SW-acclimated medaka (Oryzias latipes) and examined its functions in medaka embryos. A phylogenetic analysis showed that the evolutionary relationships of mammalian NHE2 and NHE4 are close to those of fish NHE2. A gene structure analysis showed that tetrapod NHE4 might be a tandem duplication of fish NHE2. Immunohistochemistry with a medaka-specific antibody localized NHE2 to the basolateral membrane of ionocytes. Lost-of-function experiments with photo-activated morpholino oligonucleotides showed that both H+ and Cl– secretion by ionocytes were suppressed in NHE2-knockdown embryos, suggesting that the basolateral NHE2 facilitates acid and salt secretion by ionocytes of medaka in seawater.
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Affiliation(s)
- Sian-Tai Liu
- Department of Life Science, School of Life Sciences, National Taiwan Normal University, Taipei City, Taiwan
| | - Jiun-Lin Horng
- Department of Anatomy and Cell Biology, School of Medicine, College of Medicine, Taipei Medical University, Taipei City, Taiwan
| | - Li-Yih Lin
- Department of Life Science, School of Life Sciences, National Taiwan Normal University, Taipei City, Taiwan
- *Correspondence: Li-Yih Lin,
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Peng Y, Shi H, Liu Y, Huang Y, Zheng R, Jiang D, Jiang M, Zhu C, Li G. RNA Sequencing Analysis Reveals Divergent Adaptive Response to Hypo- and Hyper-Salinity in Greater Amberjack (Seriola dumerili) Juveniles. Animals (Basel) 2022; 12:ani12030327. [PMID: 35158652 PMCID: PMC8833429 DOI: 10.3390/ani12030327] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 01/23/2022] [Accepted: 01/24/2022] [Indexed: 02/01/2023] Open
Abstract
Simple Summary The gill tanscriptomes of greater amberjack (Seriola dumerili) reared under different salinity stress were analyzed. The regulatory networks of salinity-related pathways were explored through Kyoto Encyclopedia of Gene and Genome (KEGG) pathway enrichment and bioinformatics analyses. This will be of great value in understanding the molecular basis of salinity adaptation in greater amberjack. Abstract Salinity significantly affects physiological and metabolic activities, breeding, development, survival, and growth of marine fish. The greater amberjack (Seriola dumerili) is a fast-growing species that has immensely contributed to global aquaculture diversification. However, the tolerance, adaptation, and molecular responses of greater amberjack to salinity are unclear. This study reared greater amberjack juveniles under different salinity stresses (40, 30, 20, and 10 ppt) for 30 days to assess their tolerance, adaptation, and molecular responses to salinity. RNA sequencing analysis of gill tissue was used to identify genes and biological processes involved in greater amberjack response to salinity stress at 40, 30, and 20 ppt. Eighteen differentially expressed genes (DEGs) (nine upregulated and nine downregulated) were identified in the 40 vs. 30 ppt group. Moreover, 417 DEGs (205 up-regulated and 212 down-regulated) were identified in the 20 vs. 30 ppt group. qPCR and transcriptomic analysis indicated that salinity stress affected the expression of genes involved in steroid biosynthesis (ebp, sqle, lss, dhcr7, dhcr24, and cyp51a1), lipid metabolism (msmo1, nsdhl, ogdh, and edar), ion transporters (slc25a48, slc37a4, slc44a4, and apq4), and immune response (wnt4 and tlr5). Furthermore, KEGG pathway enrichment analysis showed that the DEGs were enriched in steroid biosynthesis, lipids metabolism, cytokine–cytokine receptor interaction, tryptophan metabolism, and insulin signaling pathway. Therefore, this study provides insights into the molecular mechanisms of marine fish adaptation to salinity.
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Affiliation(s)
- Yuhao Peng
- Guangdong Research Center on Reproductive Control and Breeding Technology of Indigenous Valuable Fish Species, Guangdong Provincial Engineering Laboratory for Mariculture Organism Breeding, Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Fisheries College, Guangdong Ocean University, Zhanjiang 524088, China; (Y.P.); (H.S.); (Y.L.); (Y.H.); (R.Z.); (D.J.); (M.J.); (C.Z.)
| | - Hongjuan Shi
- Guangdong Research Center on Reproductive Control and Breeding Technology of Indigenous Valuable Fish Species, Guangdong Provincial Engineering Laboratory for Mariculture Organism Breeding, Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Fisheries College, Guangdong Ocean University, Zhanjiang 524088, China; (Y.P.); (H.S.); (Y.L.); (Y.H.); (R.Z.); (D.J.); (M.J.); (C.Z.)
| | - Yuqi Liu
- Guangdong Research Center on Reproductive Control and Breeding Technology of Indigenous Valuable Fish Species, Guangdong Provincial Engineering Laboratory for Mariculture Organism Breeding, Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Fisheries College, Guangdong Ocean University, Zhanjiang 524088, China; (Y.P.); (H.S.); (Y.L.); (Y.H.); (R.Z.); (D.J.); (M.J.); (C.Z.)
| | - Yang Huang
- Guangdong Research Center on Reproductive Control and Breeding Technology of Indigenous Valuable Fish Species, Guangdong Provincial Engineering Laboratory for Mariculture Organism Breeding, Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Fisheries College, Guangdong Ocean University, Zhanjiang 524088, China; (Y.P.); (H.S.); (Y.L.); (Y.H.); (R.Z.); (D.J.); (M.J.); (C.Z.)
| | - Renchi Zheng
- Guangdong Research Center on Reproductive Control and Breeding Technology of Indigenous Valuable Fish Species, Guangdong Provincial Engineering Laboratory for Mariculture Organism Breeding, Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Fisheries College, Guangdong Ocean University, Zhanjiang 524088, China; (Y.P.); (H.S.); (Y.L.); (Y.H.); (R.Z.); (D.J.); (M.J.); (C.Z.)
| | - Dongneng Jiang
- Guangdong Research Center on Reproductive Control and Breeding Technology of Indigenous Valuable Fish Species, Guangdong Provincial Engineering Laboratory for Mariculture Organism Breeding, Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Fisheries College, Guangdong Ocean University, Zhanjiang 524088, China; (Y.P.); (H.S.); (Y.L.); (Y.H.); (R.Z.); (D.J.); (M.J.); (C.Z.)
| | - Mouyan Jiang
- Guangdong Research Center on Reproductive Control and Breeding Technology of Indigenous Valuable Fish Species, Guangdong Provincial Engineering Laboratory for Mariculture Organism Breeding, Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Fisheries College, Guangdong Ocean University, Zhanjiang 524088, China; (Y.P.); (H.S.); (Y.L.); (Y.H.); (R.Z.); (D.J.); (M.J.); (C.Z.)
| | - Chunhua Zhu
- Guangdong Research Center on Reproductive Control and Breeding Technology of Indigenous Valuable Fish Species, Guangdong Provincial Engineering Laboratory for Mariculture Organism Breeding, Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Fisheries College, Guangdong Ocean University, Zhanjiang 524088, China; (Y.P.); (H.S.); (Y.L.); (Y.H.); (R.Z.); (D.J.); (M.J.); (C.Z.)
- Southern Marine Science and Engineering Guangdong Laboratory, Zhanjiang 524025, China
| | - Guangli Li
- Guangdong Research Center on Reproductive Control and Breeding Technology of Indigenous Valuable Fish Species, Guangdong Provincial Engineering Laboratory for Mariculture Organism Breeding, Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Fisheries College, Guangdong Ocean University, Zhanjiang 524088, China; (Y.P.); (H.S.); (Y.L.); (Y.H.); (R.Z.); (D.J.); (M.J.); (C.Z.)
- Correspondence:
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Lin CH, Hu HJ, Chuang HJ, Tsou YL, Hwang PP. Cortisol and glucocorticoid receptor 2 regulate acid secretion in medaka (Oryzias latipes) larvae. J Comp Physiol B 2021; 191:855-864. [PMID: 34274982 DOI: 10.1007/s00360-021-01390-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 05/19/2021] [Accepted: 07/06/2021] [Indexed: 11/26/2022]
Abstract
Freshwater fish live in environments where pH levels fluctuate more than those in seawater. During acidic stress, the acid-base balance in these fish is regulated by ionocytes in the gills, which directly contact water and function as an external kidney. In ionocytes, apical acid secretion is largely mediated by H+-ATPase and the sodium/hydrogen exchanger (NHE). Control of this system was previously proposed to depend on the hormone, cortisol, mostly based on studies of zebrafish, a stenohaline fish, which utilize H+-ATPase as the main route for apical acid secretion. However, the role of cortisol is poorly understood in euryhaline fish species that preferentially use NHE as the main transporter. In the present study, we explored the role of cortisol in NHE-mediated acid secretion in medaka larvae. mRNA expression levels of transporters related to acid secretion and cortisol-synthesis enzyme were enhanced by acidic FW treatment (pH 4.5, 2 days) in medaka larvae. Moreover, exogenous cortisol treatment (25 mg/L, 2 days) resulted in upregulation of nhe3 and rhcg1 expression, as well as acid secretion in 7 dpf medaka larvae. In loss-of-function experiments, microinjection of glucocorticoid receptor (GR)2 morpholino (MO) caused reductions in nhe3 and rhcg1 expression and diminished acid secretion, but microinjection of mineralocorticoid receptor (MR) and GR1 MOs did not. Together, these results suggest a conserved action of cortisol and GR2 on fish body fluid acid-base regulation.
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Affiliation(s)
- Chia-Hao Lin
- Department of Marine Biotechnology, National Kaohsiung University of Science and Technology, Kaohsiung, 81143, Taiwan.
- The iEGG and Animal Biotechnology Center, National Chung Hsing University, Taichung, 40227, Taiwan.
| | - Huei-Jyun Hu
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Hsin-Ju Chuang
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, 11529, Taiwan
- Department of Life Science, National Taiwan University, Taipei, 10607, Taiwan
| | - Yi-Ling Tsou
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Pung-Pung Hwang
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, 11529, Taiwan.
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Slc4 Gene Family in Spotted Sea Bass (Lateolabrax maculatus): Structure, Evolution, and Expression Profiling in Response to Alkalinity Stress and Salinity Changes. Genes (Basel) 2020; 11:genes11111271. [PMID: 33126655 PMCID: PMC7692064 DOI: 10.3390/genes11111271] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 10/23/2020] [Accepted: 10/26/2020] [Indexed: 12/11/2022] Open
Abstract
The solute carrier 4 (SLC4) family is a class of cell membranes transporters involved in base transport that plays crucial roles in diverse physiological processes. In our study, 15 slc4 genes were identified and annotated in spotted sea bass, including five members of Cl−/HCO3− exchangers, eight genes coding Na+-dependent HCO3− transporters, and two copies of Na+-coupled borate transporters. The gene sequence and structure, chromosomal and syntenic arrangement, phylogenetic and evolution profiles were analyzed. Results showed that the slc4 gene in teleosts obviously expanded compared with higher vertebrates, arising from teleost-specific whole genome duplication event. Most gene sites of slc4 in spotted sea bass were under strong purifying selection during evolution, while positive selection sites were only detected in slc4a1b, slc4a8, and slc4a10b. Additionally, qRT-PCR results showed that different slc4 genes exhibited distinct branchial expression patterns after alkalinity and salinity stresses, of which the strongly responsive members may play essential roles during these physiological processes. Our study provides the systemic overview of the slc4 gene family in spotted sea bass and enables a better understanding for the evolution of this family and further deciphering the biological roles in maintaining ion and acid–base homeostasis in teleosts.
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Yao Z, Schauer KL, Ruhr IM, Mager EM, Heuer RM, Grosell M. A marine teleost, Opsanus beta, compensates acidosis in hypersaline water by H + excretion or reduced HCO 3- excretion rather than HCO 3- uptake. J Comp Physiol B 2020; 191:85-98. [PMID: 33070210 DOI: 10.1007/s00360-020-01320-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 09/10/2020] [Accepted: 09/29/2020] [Indexed: 10/23/2022]
Abstract
Increases in ambient salinity demand parallel increases in intestinal base secretion for maintenance of osmoregulatory status, which is likely the cause of a transient acidosis following transfer of euryhaline fish from freshwater to seawater. It was predicted that transfer of the marine Gulf toadfish (Opsanus beta) from seawater (35 ppt) to hypersaline (60 ppt) seawater (HSW) would lead to a transient acidosis that would be compensated by increases in branchial acid excretion to offset the acid-base disturbance. Toadfish exposed to HSW showed a significant decrease in blood pH and [HCO3-] but no increase in pCO2, followed by a full recovery after 48-96 h. A similar metabolic acidosis and recovery was found when fish were exposed to 60-ppt HCO3--free seawater (HEPES-buffered), which may suggest that compensation for intestinal base loss during hypersaline treatment is from gill H+ excretion rather than gill HCO3- uptake. However, we cannot rule out that reduced branchial HCO3- excretion contributed to an increase in net acid excretion. Since colchicine prevents full compensation, translocation of H+ and/or HCO3- transporters between cytosolic compartments and plasma membrane fractions might be involved in compensating for the hypersalinity-induced acidosis. Translocation of transporters rather than de novo synthesis may represent a faster and less energetically demanding response to rapidly fluctuating and high salinities encountered by toadfish in their natural environment.
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Affiliation(s)
- Zongli Yao
- Sino-US joint laboratory of Aquatic Animal Physiology, East China Sea Fisheries Research Institute, Chinese Academy of Fisheries Sciences, Shanghai, China. .,Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, USA.
| | - Kevin L Schauer
- Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, USA
| | - Ilan M Ruhr
- Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, USA.,Cardiovascular Sciences, School of Medical Sciences, The University of Manchester, Manchester, UK
| | - Edward M Mager
- Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, USA.,Department of Biological Sciences, University of North Texas, Denton, TX, USA
| | - Rachael M Heuer
- Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, USA
| | - Martin Grosell
- Sino-US joint laboratory of Aquatic Animal Physiology, East China Sea Fisheries Research Institute, Chinese Academy of Fisheries Sciences, Shanghai, China.,Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, USA
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Lin LY, Zheng JA, Huang SC, Hung GY, Horng JL. Ammonia exposure impairs lateral-line hair cells and mechanotransduction in zebrafish embryos. CHEMOSPHERE 2020; 257:127170. [PMID: 32497837 DOI: 10.1016/j.chemosphere.2020.127170] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 05/18/2020] [Accepted: 05/20/2020] [Indexed: 06/11/2023]
Abstract
Ammonia (including NH3 and NH4+) is a major pollutant of freshwater environments. However, the toxic effects of ammonia on the early stages of fish are not fully understood, and little is known about the effects on the sensory system. In this study, we hypothesized that ammonia exposure can cause adverse effects on embryonic development and impair the lateral line system of fish. Zebrafish embryos were exposed to high-ammonia water (10, 15, 20, 25, and 30 mM NH4Cl; pH 7.0) for 96 h (0-96 h post-fertilization). The body length, heart rate, and otic vesicle size had significantly decreased with ≥15 mM NH4Cl, while the number and function of lateral-line hair cells had decreased with ≥10 mM NH4Cl. The mechanoelectrical transduction (MET) channel-mediated Ca2+ influx was measured with a scanning ion-selective microelectrode technique to reveal the function of hair cells. We found that NH4+ (≥5 mM NH4Cl) entered hair cells and suppressed the Ca2+ influx of hair cells. Neomycin and La3+ (MET channel blockers) suppressed NH4+ influx, suggesting that NH4+ enters hair cells via MET channels in hair bundles. In conclusion, this study showed that ammonia exposure (≥10 mM NH4Cl) can cause adverse effects in zebrafish embryos, and lateral-line hair cells are sensitive to ammonia exposure.
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Affiliation(s)
- Li-Yih Lin
- Department of Life Science, School of Life Science, National Taiwan Normal University, Taipei, 11677, Taiwan
| | - Jie-An Zheng
- Department of Life Science, School of Life Science, National Taiwan Normal University, Taipei, 11677, Taiwan
| | - Shun-Chih Huang
- Department of Life Science, School of Life Science, National Taiwan Normal University, Taipei, 11677, Taiwan
| | - Giun-Yi Hung
- Division of Pediatric Hematology and Oncology, Department of Pediatrics, Taipei Veterans General Hospital, Taipei, 11217, Taiwan; Department of Pediatrics, Faculty of Medicine, School of Medicine, National Yang-Ming University, Taipei, 11221, Taiwan
| | - Jiun-Lin Horng
- Department of Anatomy and Cell Biology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, 11031, Taiwan.
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12
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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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13
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Hilgers L, Schwarzer J. The untapped potential of medaka and its wild relatives. eLife 2019; 8:46994. [PMID: 31287418 PMCID: PMC6615862 DOI: 10.7554/elife.46994] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 06/12/2019] [Indexed: 01/04/2023] Open
Abstract
The medaka is a fish that has served as a model organism for over a century, yet there is still much to learn about its life in the wild. Here we summarize the current knowledge, highlight recent progress and outline remaining gaps in our understanding of the natural history of medaka. It has also become clear over time that rather than being a single species, medaka comprises an entire species complex, so disentangling the species boundaries is an important goal for future research. Moreover, medaka and other ricefishes exhibit striking functional diversity, little of which has been investigated to date. As such, there are opportunities to use the resources developed for medaka to study other ricefishes, and to learn more about medaka itself in an evolutionary context.
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Affiliation(s)
- Leon Hilgers
- Zoological Research Museum Alexander Koenig, Bonn, Germany
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14
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Hung GY, Wu CL, Chou YL, Chien CT, Horng JL, Lin LY. Cisplatin exposure impairs ionocytes and hair cells in the skin of zebrafish embryos. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2019; 209:168-177. [PMID: 30784778 DOI: 10.1016/j.aquatox.2019.02.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 02/11/2019] [Accepted: 02/11/2019] [Indexed: 06/09/2023]
Abstract
This study aimed to assess the sublethal effects of a platinum-based compound, cisplatin, using a zebrafish model. Zebrafish embryos were incubated in different concentrations of cisplatin at 0-96 h post-fertilization. Using a non-invasive, scanning ion-selective electrode technique (SIET), we measured the functions of hair cells (Ca2+ influx) and ionocytes ([H+] gradients). The survival rate, hatching rate, phenotype, body length, whole-body ion (Na+, Cl-, and Ca2+) and Pt contents were also determined. The effects of cisplatin on zebrafish embryos were demonstrated as first impairing hair cell function (at 1 μM of cisplatin), the hair cell number, and body ion content of Cl- (at 10 μM of cisplatin), then decreasing ionocyte acid secretion and overall body ion contents of Na+ and Ca2+ (at 50 μM of cisplatin). The body length and ionocyte density decreased at 100 μM of cisplatin, and survival decreased at 500 μM of cisplatin. As the cisplatin concentration increased, the accumulation of Pt in fish embryos also increased. These results revealed that hair cells are significantly more susceptible to cisplatin toxicity than ionocytes. By determining the lowest observed effective concentration of cisplatin that caused in vivo functional alterations of zebrafish hair cells and skin ionocytes, this model demonstrated 500-fold greater sensitivity than by detecting changes in survival, for early assessment of the effects of platinum-based chemotherapeutic drugs on fish.
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Affiliation(s)
- Giun-Yi Hung
- Department of Life Science, School of Life Science, National Taiwan Normal University, Taipei 11677, Taiwan; Division of Pediatric Hematology and Oncology, Department of Pediatrics, Taipei Veterans General Hospital, Taipei 11217, Taiwan; Department of Pediatrics, Faculty of Medicine, School of Medicine, National Yang-Ming University, Taipei 11221, Taiwan
| | - Ciao-Ling Wu
- Department of Life Science, School of Life Science, National Taiwan Normal University, Taipei 11677, Taiwan
| | - Yi-Ling Chou
- Department of Life Science, School of Life Science, National Taiwan Normal University, Taipei 11677, Taiwan
| | - Chiang-Ting Chien
- Department of Life Science, School of Life Science, National Taiwan Normal University, Taipei 11677, Taiwan
| | - Jiun-Lin Horng
- Department of Anatomy and Cell Biology, School of Medicine, College of Medicine, Taipei Medical University, Taipei 11042, Taiwan
| | - Li-Yih Lin
- Department of Life Science, School of Life Science, National Taiwan Normal University, Taipei 11677, Taiwan.
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15
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Chen XL, Zhang B, Chng YR, Ong JLY, Chew SF, Wong WP, Lam SH, Ip YK. Na +/H + Exchanger 3 Is Expressed in Two Distinct Types of Ionocyte, and Probably Augments Ammonia Excretion in One of Them, in the Gills of the Climbing Perch Exposed to Seawater. Front Physiol 2017; 8:880. [PMID: 29209224 PMCID: PMC5701670 DOI: 10.3389/fphys.2017.00880] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 10/18/2017] [Indexed: 01/22/2023] Open
Abstract
The freshwater climbing perch, Anabas testudineus, is an euryhaline teleost and an obligate air-breather with the ability to actively excrete ammonia. Members of the Na+/H+ exchanger (NHE) family help maintain intracellular pH homeostasis and ionic balance through the electroneutral exchange of Na+ and H+. This study aimed to obtain, from the gills of A. testudineus, the full cDNA coding sequence of nhe3, and to determine the effects of exposure to seawater or 100 mmol l-1 of NH4Cl in fresh water on its mRNA and protein expression levels. Efforts were also made to elucidate the type of ionocyte that Nhe3 was associated with in the branchial epithelium of A. testudineus. The transcript level and protein abundance of nhe3/Nhe3 were very low in the gills of freshwater A. testudineus, but they increased significantly in the gills of fish acclimated to seawater. In the gills of fish exposed to seawater, Nhe3 was expressed in two distinct types of seawater-inducible Na+/K+-ATPase (Nka)-immunoreactive ionocytes. In Nkaα1b-immunoreactive ionocytes, Nhe3 had an apical localization. As these ionocytes also expressed apical Rhcg1 and basolateral Rhcg2, which are known to transport ammonia, they probably participated in proton-facilitated ammonia excretion in A. testudineus during seawater acclimation. In Nkaα1c-immunoreactive ionocytes, Nhe3 was atypically expressed in the basolateral membrane, and its physiological function is uncertain. For A. testudineus exposed to NH4Cl in fresh water, the transcript and protein expression levels of nhe3/Nhe3 remained low. In conclusion, the branchial Nhe3 of A. testudineus plays a greater physiological role in passive ammonia transport and acid-base balance during seawater acclimation than in active ammonia excretion during environmental ammonia exposure.
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Affiliation(s)
- Xiu L. Chen
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Biyan Zhang
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - You R. Chng
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Jasmine L. Y. Ong
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Shit F. Chew
- Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University, Singapore, Singapore
| | - Wai P. Wong
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Siew H. Lam
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
- NUS Environmental Research Institute, National University of Singapore, Singapore, Singapore
| | - Yuen K. Ip
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
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Inokuchi M, Nakamura M, Miyanishi H, Hiroi J, Kaneko T. Functional classification of gill ionocytes and spatiotemporal changes in their distribution after transfer from seawater to fresh water in Japanese seabass. J Exp Biol 2017; 220:4720-4732. [DOI: 10.1242/jeb.167320] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Accepted: 10/24/2017] [Indexed: 01/26/2023]
Abstract
Spatiotemporal changes in branchial ionocyte distribution were investigated following transfer from seawater (SW) to fresh water (FW) in Japanese seabass. The mRNA expression levels of cystic fibrosis transmembrane conductance regulator (CFTR) and Na+/K+/2Cl− cotransporter 1a (NKCC1a) in the gills rapidly decreased after transfer to FW, whereas Na+/H+ exchanger 3 (NHE3) and Na+/Cl− cotransporter 2 (NCC2) expressions were upregulated following the transfer. By quadruple-color whole-mount immunofluorescence staining with anti-Na+/K+-ATPase, anti-NHE3, anti-CFTR and T4 (anti-NKCC1a/NCC2) antibodies, we classified ionocytes into one SW-type and two FW-types; NHE3 cell and NCC2 cell. Time-course observation after transfer revealed an intermediate type between SW-type and FW-type NHE3 ionocytes, suggesting functional plasticity of ionocytes. Finally, on the basis of the ionocyte classification of Japanese seabass, we observed the location of ionocyte subtypes on frozen sections of the gill filaments stained by triple-color immunofluorescence staining. Our observation indicated that SW-type ionocytes transformed into FW-type NHE3 ionocytes and at the same time shifted their distribution from filaments to lamellae. On the other hand, FW-specific NCC2 ionocytes appeared mainly in the filaments. Taken together, these findings indicated that ionocytes originated from undifferentiated cells in the filaments and expanded their distribution to the lamellae during FW acclimation.
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Affiliation(s)
- Mayu Inokuchi
- Department of Life Sciences, Toyo University, Itakura, Gunma 374-0193, Japan
| | - Masahiro Nakamura
- National Research Institute of Fisheries and Environment of Inland Sea, Fisheries Research Agency, Imabari, Ehime 794-2305, Japan
| | - Hiroshi Miyanishi
- Faculty of Agriculture, University of Miyazaki, Gakuen-kibanadai-nishi, Miyazaki 889-2192, Japan
| | - Junya Hiroi
- Department of Anatomy, St. Marianna University School of Medicine, Kawasaki, Kanagawa 216-8511, Japan
| | - Toyoji Kaneko
- Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo 113-8657, Japan
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