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Localization of the Neuropeptide Arginine Vasotocin and Its Receptor in the Osmoregulatory Organs of Black Porgy, Acanthopagrus schlegelii: Gills, Kidneys, and Intestines. Int J Mol Sci 2022; 23:ijms232113421. [DOI: 10.3390/ijms232113421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 10/26/2022] [Accepted: 10/28/2022] [Indexed: 11/06/2022] Open
Abstract
The neurohypophysial hormone arginine vasotocin (avt) and its receptor (avtr) regulates ions in the osmoregulatory organs of euryhaline black porgy (Acanthopagrus schlegelii). The localization of avt and avtr transcripts in the osmoregulatory organs has yet to be demonstrated. Thus, in the present study, we performed an in situ hybridization analysis to determine the localization of avt and avtr in the gills, kidneys, and intestines of the black porgy. The avt and avtr transcripts were identified in the filament and lamellae region of the gills in the black porgy. However, the basal membrane of the filament contained more avt and avtr transcripts. Fluorescence double tagging analysis revealed that avt and avtr mRNAs were partially co-localized with α-Nka-ir cells in the gill filament. The proximal tubules, distal tubules, and collecting duct of the kidney all had positive hybridization signals for the avt and avtr transcripts. Unlike the α-Nka immunoreactive cells, the avt and avtr transcripts were found on the basolateral surface of the distal convoluted tubule and in the entire cells of the proximal convoluted tubules of the black porgy kidney. In the intestine, the avt and avtr transcripts were found in the basolateral membrane of the enterocytes. Collectively, this study provides a summary of evidence suggesting that the neuropeptides avt and avtr with α-Nka-ir cells may have functions in the gills, kidneys, and intestines via ionocytes.
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Nobata S, Iino Y, Kawakami T, Sasaki K, Kitagawa T, Hyodo S. Significance of sea entry pathway of chum salmon Oncorhynchus keta fry, inferred from the differential expressions of Na +,K +-ATPase α-subunit genes in the gills. Comp Biochem Physiol A Mol Integr Physiol 2022; 269:111224. [PMID: 35460896 DOI: 10.1016/j.cbpa.2022.111224] [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: 03/14/2022] [Revised: 04/14/2022] [Accepted: 04/14/2022] [Indexed: 10/18/2022]
Abstract
Na+,K+-ATPase (NKA) α-subunit 1a (α1a) and 1b (α1b) gene expressions in the gills are changeable in response to ambient salinity in a few salmonids. In this study, the expressions were compared among ambient salinities and used to infer sea entry migration of chum salmon Oncorhynchus keta fry. The expression of α1a decreased from the 2 days after seawater (SW) transfer from freshwater (FW) and was significantly lower in SW-acclimated fry than that in FW-fry. On the other hand, the expression of α1b peaked on the first to second day after SW transfer and then settled to a level 2-fold higher than in FW-fry. In fry caught in the waterfronts of the beaches, the expression levels were quite similar to those on the first and second days after SW transfer, whereas, in fry caught off beach, the expressions were identical to those of SW-acclimated fry. These suggest that fry adapt to SW with moving along the shoal in the bay, and move to off beach after completing SW adaptation. One of the physiological significances in a usage of waterfront may be to transform the gills to SW type. Only fry on the 2 days after SW transfer failed to exhibit condition factor-dependency of burst swimming, probably due to physiological perturbation, which may be related to poor predation avoidance. The physiological approach used in this study inferred sea entry migration of fry; furthermore, it shows the possible significance of adaptation to SW in the shoal is to reduce predation risk.
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Affiliation(s)
- Shigenori Nobata
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, University of Tokyo, 5-1-5, Kashiwanoha, Kashiwa, Chiba 277-8564, Japan; International Coastal Research Center, Atmosphere and Ocean Research Institute, University of Tokyo, 1-19-8, Akahama, Otsuchi, Kamihei, Iwate 028-1102, Japan.
| | - Yuki Iino
- International Coastal Research Center, Atmosphere and Ocean Research Institute, University of Tokyo, 1-19-8, Akahama, Otsuchi, Kamihei, Iwate 028-1102, Japan.
| | - Tatsuya Kawakami
- International Coastal Research Center, Atmosphere and Ocean Research Institute, University of Tokyo, 1-19-8, Akahama, Otsuchi, Kamihei, Iwate 028-1102, Japan.
| | - Kei Sasaki
- Environment and Fisheries Applied Techniques Research Department, Fisheries Technology Institute, Japan Fisheries Research and Education Agency, 4-9-1, Sakiyama, Miyako, Iwate 027-0097, Japan.
| | - Takashi Kitagawa
- International Coastal Research Center, Atmosphere and Ocean Research Institute, University of Tokyo, 1-19-8, Akahama, Otsuchi, Kamihei, Iwate 028-1102, Japan.
| | - Susumu Hyodo
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, University of Tokyo, 5-1-5, Kashiwanoha, Kashiwa, Chiba 277-8564, Japan.
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Flerova E, Yurchenko VV, Sapozhnikova YP, Sendek DS, Titov SF, Morozov A. Microanatomy and ultrastructure of kidney interstitial cells and nephron in brown trout (Salmo trutta Linnaeus, 1758) at different stages of the life cycle. CAN J ZOOL 2022. [DOI: 10.1139/cjz-2021-0167] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The study focuses on the microanatomy and ultrastructural changes in the trunk kidney interstitium cells and nephrons in parr, smolt and spawning brown trout Salmo trutta Linnaeus, 1758 sampled in Luga River and Solka River, the tributaries of the Baltic Sea. Regardless of the type of cells or their structure, there were changes in their areas and the number and structure of organelles responsible for the transport, synthetic and energetic function of cells. Our data on the morphology of the nephron combined with data on its physiology suggest a fundamental change in kidney function during the parr-smolt transformation before migration; this could be a preadaptation for a successful life in saltwater where urine output is sharply reduced. Thus, detected structural features of the trunk kidney in brown trout S. trutta are cytological markers of the migration process. The numbers of lymphocytes, neutrophils and eosinophils with segmented nuclei increased from parr to smolts and then to spawners; only monotypic specific granules in neutrophils were found in smolts and spawners. Cells with radially arranged vesicles were described for the first time in brown trout S. trutta renal interstitium. Their origin has not yet been established. The shape of these cells changed from spherical to trihedral during fish maturation. All the above ultrastructural changes of renal interstitium cells could be considered cytological markers of cell maturity.
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Affiliation(s)
- Ekaterina Flerova
- Yaroslavl Scientific Research Institute of Livestock Breeding and Forage Production – Federal State Budget Sciences Institution “Federal Williams Research Center of Forage Production and Agroecology”, livestock technology, Lenin St. 1, Mikhailovskiy, Yaroslavl, Russian Federation, 157517,
- P.G. Demidov Yaroslavl State University, Department of Human and Animal Physiology, Sovetskaya St. 14, Yaroslav, Russian Federation, 150003,
| | - Victoria V. Yurchenko
- Papanin Institute for Biology of Inland Waters Russian Academy of Sciences, IBIW 109, Borok, Yaroslavl, Russian Federation, 152742
| | - Yulia P. Sapozhnikova
- Limnological Institute of Siberian Branch of Russian Academy of Sciences, 204334, Irkutsk, Russian Federation
| | - Dmitry S. Sendek
- Federal Agency for Fishery, Russian Federal “Research Institute of Fisheries and Oceanography” “VNIRO”, Saint Petersburg brunch of VNIRO, St. Petersburg, Russian Federation
| | - Sergey F. Titov
- Federal Agency for Fishery, Russian Federal “Research Institute of Fisheries and Oceanography” “VNIRO”, Saint Petersburg brunch of VNIRO , St. Petersburg, Russian Federation
| | - Alexey Morozov
- I.D. Papanin Institute of the Biology of Inland Waters, Russian Academy of Sciences, Borok, Russian Federation
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Szeligowski RV, Scanley JA, Broadbridge CC, Brady SP. Road salt compromises functional morphology of larval gills in populations of an amphibian. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 292:118441. [PMID: 34728326 DOI: 10.1016/j.envpol.2021.118441] [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: 06/19/2021] [Revised: 09/07/2021] [Accepted: 10/28/2021] [Indexed: 06/13/2023]
Abstract
Across the planet, winter de-icing practices have caused secondary salinization of freshwater habitats. Many amphibians are vulnerable because of permeable skin and reliance on small ponds, where salinity can be high. Early developmental stages of amphibians are especially sensitive to salt, and larvae developing in salt-polluted environments must osmoregulate through ion exchange in gills. Though ionoregulation in amphibian gills is generally understood, the role of gill morphology remains poorly described. Yet gill structure should affect ionoregulatory capacity, for instance in terms of available surface area. As larval amphibian gills also play critical roles in gas exchange and foraging, changes in gill morphology from salt pollution potentially affect not only osmoregulation, but also respiration and feeding. Here, we used an exposure experiment to quantify salinity effects on larval gill morphology in wood frogs (Rana sylvatica). We measured a suite of morphological traits on gill tufts-where ionoregulation and gas exchange occur-and on gill filters used in feeding. Larvae raised in elevated salinity developed larger gill tufts but with lower surface area to volume ratio. Epithelial cells on these tufts were less circular but occurred at higher densities. Gill filters showed increased spacing, likely reducing feeding efficiency. Many morphological gill traits responded quadratically, suggesting that salinity might induce plasticity in gills at intermediate concentrations until energetic demands exceed plasticity. Together, these changes likely diminish ionoregulatory and respiratory functionality of gill tufts, and compromise feeding functionality of gill filters. Thus, a singular change in aquatic environment from a widespread pollutant appears to generate a suite of consequences via changes in gill morphology. Critically, these changes in traits likely compound the severity of fitness impacts in populations dwelling in salinized environments, whereby ionoregulatory energetic demands should increase respiratory and foraging demands, but in individuals who possess structures poorly adapted for these functions.
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Affiliation(s)
- Richard V Szeligowski
- Biology Department, Southern Connecticut State University, New Haven, CT, 06515, USA.
| | - Jules A Scanley
- Center for Nanotechnology, Connecticut State Colleges and Universities, New Haven, CT, 06515, USA
| | - Christine C Broadbridge
- Center for Nanotechnology, Connecticut State Colleges and Universities, New Haven, CT, 06515, USA
| | - Steven P Brady
- Biology Department, Southern Connecticut State University, New Haven, CT, 06515, USA
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Plaul SE, Díaz AO, Barbeito CG. Gill morphology and morphometry of the facultative air-breathing armoured catfish, Corydoras paleatus, in relation on aquatic respiration. JOURNAL OF FISH BIOLOGY 2021; 99:1318-1327. [PMID: 34180055 DOI: 10.1111/jfb.14837] [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: 02/04/2021] [Revised: 06/09/2021] [Accepted: 06/23/2021] [Indexed: 06/13/2023]
Abstract
The Neotropical armoured catfish Corydoras paleatus is a facultative air-breathing teleost commonly exported as ornamental fish. In this species, air breathing enables it to survive and inhabit freshwater environments with low oxygen levels. Therefore, it is important to analyse the gills from a morphological aspect and its dimensions in relation to body mass with reference to aquatic respiration. For that, the gills were analysed using a stereoscopic microscope for morphometric studies, and structural and ultrastructural studies were carried out to compare the four branchial arches. Furthermore, two immunohistochemical techniques were used to locate and identify the presence of a Na+ /K+ pump. The characterization of the potential for cell proliferation of this organ was assessed using an anti-PCNA antibody. The results show that gills of C. paleatus present some characteristics related to its diet and lifestyle, such as the limited development of gill rakers and the abundance of taste buds. In addition, other special features associated with the environment and bimodal breathing were observed: scarce and absent mucous cells (MCs) in the gill filaments and branchial lamellae, respectively, and the localization of mitochondria-rich cells (MRCs) covering the basal third of the branchial lamellae, which reduces the gill respiratory area. A peculiar finding in the gill epithelium of this armoured catfish was the presence of mononuclear cells with sarcomeres similar to myoid cells, whose functional importance should be determined in future studies. Finally, in C. paleatus, the interlamellar space of gill filaments is an important site for cell turnover and ionoregulation; the latter function is also performed by the branchial lamellae.
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Affiliation(s)
- Silvia E Plaul
- Laboratorio de Histología y Embriología Descriptiva, Experimental y Comparada, Facultad de Ciencias Veterinarias (FCV), Universidad Nacional de La Plata (UNLP), La Plata, Argentina
| | - Alcira O Díaz
- Laboratorio de Histología e Histoquímica, Departamento de Biología. Instituto de Investigaciones Marinas y Costeras (IIMyC), Facultad de Ciencias Exactas y Naturales, CONICET-UNMdP, Mar del Plata, Argentina
| | - Claudio G Barbeito
- Laboratorio de Histología y Embriología Descriptiva, Experimental y Comparada, Facultad de Ciencias Veterinarias (FCV), Universidad Nacional de La Plata (UNLP), La Plata, Argentina
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Wong MKS, Nobata S, Hyodo S. Enhanced osmoregulatory ability marks the smoltification period in developing chum salmon (Oncorhynchus keta). Comp Biochem Physiol A Mol Integr Physiol 2019; 238:110565. [PMID: 31493553 DOI: 10.1016/j.cbpa.2019.110565] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 08/29/2019] [Accepted: 08/30/2019] [Indexed: 11/29/2022]
Abstract
The freshwater (FW) life of chum salmon is short, as they migrate to the ocean soon after emergence from the substrate gravel of natal waters. The alevins achieve seawater (SW) acclimating ability at an early developmental stage and the details of smoltification are not clear. We examined the stage-dependent SW acclimating ability in chum salmon alevins and found a sharp increase in SW tolerance during development that resembles the physiological parr-smolt transformation seen in other salmonids. Perturbation of plasma Na+ after SW exposure was prominent from the hatched embryo stage to emerged alevins, but the plasma Na+ became highly stable and more resistant to perturbation soon after complete absorption of yolk. Marker gene expression for SW-ionocytes including Na/K-ATPase (NKA α1b), Na-K-Cl cotransporter 1a (NKCC1a), Na/H exchanger 3a (NHE3a), cystic fibrosis transmembrane conductance regulators (CFTR I and CFTR II) were all upregulated profoundly at the same stage when the alevins were challenged by SW, suggesting that the stability of plasma Na+ concentration was partly a result of elevated osmoregulatory capability. FW-ionocyte markers including NKA α1a and NHE3b were consistently downregulated independent of stage by SW exposure, suggesting that embryos at all stages respond to salinity challenge, but the increase in SW osmoregulatory capability is restricted to the developmental stage after emergence. We propose that the "smoltification period" is condensed and integrated into the early development of chum salmon, and our results can be extrapolated to the future studies on hormonal controls and developmental triggers for smoltification in salmonids.
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Affiliation(s)
- Marty Kwok-Shing Wong
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, The University of Tokyo, Chiba, Japan.
| | - Shigenori Nobata
- International Coastal Research Center, Atmosphere and Ocean Research Institute, the University of Tokyo, Otsuchi, Iwate, Japan
| | - Susumu Hyodo
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, The University of Tokyo, Chiba, Japan
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Huang W, Wen C, Zhou Z, Fu Z, Katz A, Plotnikov A, Karlish SJD, Jiang R. An Efficient One‐Pot Enzymatic Synthesis of Cardiac Glycosides with Varied Sugar Chain Lengths. Adv Synth Catal 2019. [DOI: 10.1002/adsc.201900227] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Wei Huang
- Guangdong Province Key Laboratory of Pharmacodynamic Constituents of TCM and New Drugs Research, and International Cooperative Laboratory of Traditional Chinese Medicine Modernization and Innovative Drug Development of Chinese Ministry of EducationJinan University Guangzhou 510632 People's Republic of China
| | - Chao Wen
- Guangdong Province Key Laboratory of Pharmacodynamic Constituents of TCM and New Drugs Research, and International Cooperative Laboratory of Traditional Chinese Medicine Modernization and Innovative Drug Development of Chinese Ministry of EducationJinan University Guangzhou 510632 People's Republic of China
| | - Zhen‐Ru Zhou
- Guangdong Province Key Laboratory of Pharmacodynamic Constituents of TCM and New Drugs Research, and International Cooperative Laboratory of Traditional Chinese Medicine Modernization and Innovative Drug Development of Chinese Ministry of EducationJinan University Guangzhou 510632 People's Republic of China
| | - Zhi‐Hao Fu
- Guangdong Province Key Laboratory of Pharmacodynamic Constituents of TCM and New Drugs Research, and International Cooperative Laboratory of Traditional Chinese Medicine Modernization and Innovative Drug Development of Chinese Ministry of EducationJinan University Guangzhou 510632 People's Republic of China
| | - Adriana Katz
- Department of Biomolecular SciencesWeizmann Institute of Science Rehovot Israel
| | - Alexander Plotnikov
- Department of Biomolecular SciencesWeizmann Institute of Science Rehovot Israel
| | | | - Ren‐Wang Jiang
- Guangdong Province Key Laboratory of Pharmacodynamic Constituents of TCM and New Drugs Research, and International Cooperative Laboratory of Traditional Chinese Medicine Modernization and Innovative Drug Development of Chinese Ministry of EducationJinan University Guangzhou 510632 People's Republic of China
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Alteration in branchial NKA and NKCC ion-transporter expression and ionocyte distribution in adult hilsa during up-river migration. J Comp Physiol B 2018; 189:69-80. [PMID: 30483930 DOI: 10.1007/s00360-018-1193-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 11/08/2018] [Accepted: 11/22/2018] [Indexed: 01/17/2023]
Abstract
Hilsa (Tenualosa ilisha) is a clupeid that migrates from the off-shore area through the freshwater river for spawning. The purpose of this study was to investigate the involvement of branchial Na+/K+-ATPase (NKA) and Na+/K+/2Cl- cotransporter (NKCC) in maintaining ionic homeostasis in hilsa while moving across the salt barriers. Hilsa, migrating through marine and brackish waters, did not show any significant decline in NKA activity, plasma osmolality, and plasma ionic concentration. In contrast, all the parameters declined significantly, after the fish reached in freshwater zone of the river. Immunoblotting with NKA α antibody recognized two bands in gill homogenates. The intensity of the higher molecular NKA band decreased, while the other band subsequently increased accompanying the movement of hilsa from marine water (MW) to freshwater. Nevertheless, total NKA expression in marine water did not change prior to freshwater entry. NKCC expression was down-regulated in gill, parallel with NKA activity, as the fish approached to the freshwater stretch of river. The NKA α-1 and NKCC1 protein abundance decreased in freshwater individuals by 40% and 31%, respectively, compared to MW. NKA and NKCC1 were explicitly localized to branchial ionocytes and immunoreactive signal appeared throughout the cytoplasm except for the nucleus and the most apical region indicates a basolateral/tubular distribution. Immunoreactive ionocytes were distributed on the filaments and lamellae; lamellar ionocytes were more in number irrespective of habitat salinity. The decrease in salinity caused a slight reduction in ionocyte number, but not in size and the underlying distribution pattern did not alter. The overall results support previously proposed models that both the ion transporters are involved in maintaining ionic homeostasis and lamellar ionocytes may have the function in hypo-osmoregulation in migrating hilsa, unlike other anadromous teleosts.
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Katayama Y, Sakamoto T, Takanami K, Takei Y. The Amphibious Mudskipper: A Unique Model Bridging the Gap of Central Actions of Osmoregulatory Hormones Between Terrestrial and Aquatic Vertebrates. Front Physiol 2018; 9:1112. [PMID: 30154735 PMCID: PMC6102947 DOI: 10.3389/fphys.2018.01112] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 07/25/2018] [Indexed: 12/15/2022] Open
Abstract
Body fluid regulation, or osmoregulation, continues to be a major topic in comparative physiology, and teleost fishes have been the subject of intensive research. Great progress has been made in understanding the osmoregulatory mechanisms including drinking behavior in teleosts and mammals. Mudskipper gobies can bridge the gap from aquatic to terrestrial habitats by their amphibious behavior, but the studies are yet emerging. In this review, we introduce this unique teleost as a model to study osmoregulatory behaviors, particularly amphibious behaviors regulated by the central action of hormones. Regarding drinking behavior of mammals, a thirst sensation is aroused by angiotensin II (Ang II) through direct actions on the forebrain circumventricular structures, which predominantly motivates them to search for water and take it into the mouth for drinking. By contrast, aquatic teleosts can drink water that is constantly present in their mouth only by reflex swallowing, and Ang II induces swallowing by acting on the hindbrain circumventricular organ without inducing thirst. In mudskippers, however, through the loss of buccal water by swallowing, which appears to induce buccal drying on land, Ang II motivates these fishes to move to water for drinking. Thus, mudskippers revealed a unique thirst regulation by sensory detection in the buccal cavity. In addition, the neurohypophysial hormones, isotocin (IT) and vasotocin (VT), promote migration to water via IT receptors in mudskippers. VT is also dipsogenic and the neurons in the forebrain may mediate their thirst. VT regulates social behaviors as well as osmoregulation. The VT-induced migration appears to be a submissive response of subordinate mudskippers to escape from competitive and dehydrating land. Together with implications of VT in aggression, mudskippers may bridge the multiple functions of neurohypophysial hormones. Interestingly, cortisol, an important hormone for seawater adaptation and stress response in teleosts, also stimulates the migration toward water, mediated possibly via the mineralocorticoid receptor. The corticosteroid system that is responsive to external stressors can accelerate emergence of migration to alternative habitats. In this review, we suggest this unique teleost as an important model to deepen insights into the behavioral roles of these hormones in relation to osmoregulation.
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Affiliation(s)
- Yukitoshi Katayama
- Physiology Section, Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Japan
| | - Tatsuya Sakamoto
- Ushimado Marine Institute, Faculty of Science, Okayama University, Setouchi, Japan
| | - Keiko Takanami
- Ushimado Marine Institute, Faculty of Science, Okayama University, Setouchi, Japan.,Mouse Genomics Resource Laboratory, National Institute of Genetics, Mishima, Japan
| | - Yoshio Takei
- Physiology Section, Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Japan
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Na +, K +-ATPase β1 subunit associates with α1 subunit modulating a "higher-NKA-in-hyposmotic media" response in gills of euryhaline milkfish, Chanos chanos. J Comp Physiol B 2017; 187:995-1007. [PMID: 28283795 DOI: 10.1007/s00360-017-1066-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 01/06/2017] [Accepted: 02/09/2017] [Indexed: 12/17/2022]
Abstract
The euryhaline milkfish (Chanos chanos) is a popular aquaculture species that can be cultured in fresh water, brackish water, or seawater in Southeast Asia. In gills of the milkfish, Na+, K+-ATPase (i.e., NKA; sodium pump) responds to salinity challenges including changes in mRNA abundance, protein amount, and activity. The functional pump is composed of a heterodimeric protein complex composed of α- and β-subunits. Among the NKA genes, α1-β1 isozyme comprises the major form of NKA subunits in mammalian osmoregulatory organs; however, most studies on fish gills have focused on the α1 subunit and did not verify the α1-β1 isozyme. Based on the sequenced milkfish transcriptome, an NKA β1 subunit gene was identified that had the highest amino acid homology to β233, a NKA β1 subunit paralog originally identified in the eel. Despite this high level of homology to β233, phylogenetic analysis and the fact that only a single NKA β1 subunit gene exists in the milkfish suggest that the milkfish gene should be referred to as the NKA β1 subunit gene. The results of accurate domain prediction of the β1 subunit, co-localization of α1 and β1 subunits in epithelial ionocytes, and co-immunoprecipitation of α1 and β1 subunits, indicated the formation of a α1-β1 complex in milkfish gills. Moreover, when transferred to hyposmotic media (fresh water) from seawater, parallel increases in branchial mRNA and protein expression of NKA α1 and β1 subunits suggested their roles in hypo-osmoregulation of euryhaline milkfish. This study molecularly characterized the NKA β1 subunit and provided the first evidence for an NKA α1-β1 association in gill ionocytes of euryhaline teleosts.
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Griffith MB. Toxicological perspective on the osmoregulation and ionoregulation physiology of major ions by freshwater animals: Teleost fish, crustacea, aquatic insects, and Mollusca. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2017; 36:576-600. [PMID: 27808448 PMCID: PMC6114146 DOI: 10.1002/etc.3676] [Citation(s) in RCA: 88] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 04/11/2016] [Accepted: 11/01/2016] [Indexed: 05/21/2023]
Abstract
Anthropogenic sources increase freshwater salinity and produce differences in constituent ions compared with natural waters. Moreover, ions differ in physiological roles and concentrations in intracellular and extracellular fluids. Four freshwater taxa groups are compared, to investigate similarities and differences in ion transport processes and what ion transport mechanisms suggest about the toxicity of these or other ions in freshwater. Although differences exist, many ion transporters are functionally similar and may belong to evolutionarily conserved protein families. For example, the Na+ /H+ -exchanger in teleost fish differs from the H+ /2Na+ (or Ca2+ )-exchanger in crustaceans. In osmoregulation, Na+ and Cl- predominate. Stenohaline freshwater animals hyperregulate until they are no longer able to maintain hypertonic extracellular Na+ and Cl- concentrations with increasing salinity and become isotonic. Toxic effects of K+ are related to ionoregulation and volume regulation. The ionic balance between intracellular and extracellular fluids is maintained by Na+ /K+ -adenosine triphosphatase (ATPase), but details are lacking on apical K+ transporters. Elevated H+ affects the maintenance of internal Na+ by Na+ /H+ exchange; elevated HCO3- inhibits Cl- uptake. The uptake of Mg2+ occurs by the gills or intestine, but details are lacking on Mg2+ transporters. In unionid gills, SO42- is actively transported, but most epithelia are generally impermeant to SO42- . Transporters of Ca2+ maintain homeostasis of dissolved Ca2+ . More integration of physiology with toxicology is needed to fully understand freshwater ion effects. Environ Toxicol Chem 2017;36:576-600. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.
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Affiliation(s)
- Michael B. Griffith
- Office of Research and Development, National Center for Environmental Assessment, US Environmental Protection Agency, Cincinnati, Ohio, USA
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Juo JJ, Kang CK, Yang WK, Yang SY, Lee TH. A Stenohaline Medaka, Oryzias woworae, Increases Expression of Gill Na(+), K(+)-ATPase and Na(+), K(+), 2Cl(-) Cotransporter 1 to Tolerate Osmotic Stress. Zoolog Sci 2017; 33:414-25. [PMID: 27498801 DOI: 10.2108/zs150157] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The present study aimed to evaluate the osmoregulatory mechanism of Daisy's medaka, O. woworae,as well as demonstrate the major factors affecting the hypo-osmoregulatory characteristics of euryhaline and stenohaline medaka. The medaka phylogenetic tree indicates that Daisy's medaka belongs to the celebensis species group. The salinity tolerance of Daisy's medaka was assessed. Our findings revealed that 20‰ (hypertonic) saltwater (SW) was lethal to Daisy's medaka. However, 62.5% of individuals survived 10‰ (isotonic) SW with pre-acclimation to 5‰ SW for one week. This transfer regime, "Experimental (Exp.) 10‰ SW", was used in the following experiments. After 10‰ SW-transfer, the plasma osmolality of Daisy's medaka significantly increased. The protein abundance and distribution of branchial Na(+), K(+)-ATPase (NKA) and Na(+), K(+), 2Cl(-) cotransporter 1 (NKCC1) were also examined after transfer to 10‰ SW for one week. Gill NKA activity increased significantly after transfer to 10‰ SW. Meanwhile, elevation of gill NKA αα-subunit protein-abundance was found in the 10‰ SW-acclimated fish. In gill cross-sections, more and larger NKA-immunoreactive (NKA-IR) cells were observed in the Exp. 10‰ SW medaka. The relative abundance of branchial NKCC1 protein increased significantly after transfer to 10‰ SW. NKCC1 was distributed in the basolateral membrane of NKA-IR cells of the Exp. 10‰ SW group. Furthermore, a higher abundance of NKCC1 protein was found in the gill homogenates of the euryhaline medaka, O. dancena, than in that of the stenohaline medaka, O. woworae.
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Affiliation(s)
- Jiun-Jang Juo
- 1 Department of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan.,† JJJ, CKK, and WKY contributed equally to this paper
| | - Chao-Kai Kang
- 2 Tainan Hydraulics Laboratory, National Cheng Kung University, Tainan 709, Taiwan.,† JJJ, CKK, and WKY contributed equally to this paper
| | - Wen-Kai Yang
- 1 Department of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan.,† JJJ, CKK, and WKY contributed equally to this paper
| | - Shu-Yuan Yang
- 1 Department of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan
| | - Tsung-Han Lee
- 1 Department of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan.,3 Department of Biological Science and Technology, China Medical University,Taichung 404, Taiwan
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Kang CK, Lin CS, Hu YC, Tsai SC, Lee TH. The expression of VILL protein is hypoosmotic-dependent in the lamellar gill ionocytes of Otocephala teleost fish, Chanos chanos. Comp Biochem Physiol A Mol Integr Physiol 2017; 203:59-68. [DOI: 10.1016/j.cbpa.2016.08.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Revised: 05/13/2016] [Accepted: 08/16/2016] [Indexed: 02/09/2023]
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14
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Dietary salt loading and ion-poor water exposure provide insight into the molecular physiology of the rainbow trout gill epithelium tight junction complex. J Comp Physiol B 2016; 186:739-57. [DOI: 10.1007/s00360-016-0987-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 03/28/2016] [Accepted: 04/02/2016] [Indexed: 01/11/2023]
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15
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Zhao F, Wu B, Yang G, Zhang T, Zhuang P. Adaptive alterations on gill Na⁺, K⁺-ATPase activity and mitochondrion-rich cells of juvenile Acipenser sinensis acclimated to brackish water. FISH PHYSIOLOGY AND BIOCHEMISTRY 2016; 42:749-756. [PMID: 26614501 DOI: 10.1007/s10695-015-0172-4] [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: 03/07/2015] [Accepted: 11/24/2015] [Indexed: 06/05/2023]
Abstract
Understanding the physiological changes and osmoregulatory strategy is critical for anadromous species to adapt to large changes between freshwater and marine environments. In this study, juvenile Chinese sturgeon (Acipenser sinensis) were acclimated for 2 months to freshwater (FW, c. 0‰) and brackish water (BW, 15‰). Blood was assessed for changes in osmolality and ions. Gill tissue was assayed for Na(+), K(+)-ATPase (NKA) activity and immunohistochemical analysis on mitochondria-rich cells (MRCs). Serum osmolality and ions concentrations (Na(+), Cl(-) and K(+)) examined, except K(+), increased significantly in those specimens adapted to BW. However, the variations were within the range of effective hyperosmotic adaptation. The specific activity of gill NKA of juveniles adapted to BW was significantly higher (c. 1.6 times) than that of fish adapted to FW. MRCs were mainly presented in the interlamellar region of the filament and at the base of the lamella in either FW- or BW-acclimated individuals. In BW, the number and size of MRCs on filaments greatly increased. However, there was no significant difference in the number and size of the MRCs at the lamella region. Results show that juvenile Chinese sturgeon keep osmotic homeostasis in hyperosmotic environments by increasing gill NKA activity and MRCs' size and number, which is similar to other sturgeons and euryhaline teleosts.
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Affiliation(s)
- Feng Zhao
- Key Laboratory of Fisheries Ecology of the Yangtze Estuary, East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai, 200090, China.
| | - Beibei Wu
- Key Laboratory of Fisheries Ecology of the Yangtze Estuary, East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai, 200090, China
| | - Gang Yang
- Key Laboratory of Fisheries Ecology of the Yangtze Estuary, East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai, 200090, China
| | - Tao Zhang
- Key Laboratory of Fisheries Ecology of the Yangtze Estuary, East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai, 200090, China
| | - Ping Zhuang
- Key Laboratory of Fisheries Ecology of the Yangtze Estuary, East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai, 200090, China.
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Zydlewski J, Zydlewski G, Kennedy B, Gale W. Smolting in coastal cutthroat trout Onchorhynchus clarkii clarkii. JOURNAL OF FISH BIOLOGY 2014; 85:1111-1130. [PMID: 25082434 DOI: 10.1111/jfb.12480] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Accepted: 06/19/2014] [Indexed: 06/03/2023]
Abstract
Gill Na(+) , K(+) -ATPase activity, condition factor and seawater (SW) challenges were used to assess the development of smolt characteristics in a cohort of hatchery coastal cutthroat trout Oncorhynchus clarkii clarkii from the Cowlitz River in Washington State, U.S.A. Gill Na(+) , K(+) -ATPase activity increased slightly in the spring, coinciding with an increase in hypo-osmoregulatory ability. These changes were of lesser magnitude than are observed in other salmonine species. Even at the peak of tolerance, these fish exhibited notable osmotic perturbations in full strength SW. Condition factor in these hatchery fish declined steadily through the spring. Wild captured migrants from four tributaries of the Columbia River had moderately elevated gill Na(+) , K(+) -ATPase activity, consistent with smolt development and with greater enzyme activity than autumn captured juveniles from one of the tributaries, Abernathy Creek. Migrant fish also had reduced condition factor. General linear models of 7 years of data from Abernathy Creek suggest that yearly variation, advancing photoperiod (as ordinal date) and fish size (fork length) were significant factors for predicting gill Na(+) , K(+) -ATPase activity in these wild fish. Both yearly variation and temperature were significant factors for predicting condition factor. These results suggest that coastal O. c. clarkii exhibit weakly developed characteristics of smolting. These changes are influenced by environmental conditions with great individual variation. The data suggest great physiological plasticity consistent with the variable life-history tactics observed in this species.
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Affiliation(s)
- J Zydlewski
- U.S. Geological Survey, Maine Cooperative Fish and Wildlife Research Unit, 5755 Nutting Hall, Orono, ME 04469-5755, U.S.A.; Department of Wildlife Ecology, University of Maine, Orono, ME 04469, U.S.A
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17
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Yang SH, Kang CK, Kung HN, Lee TH. The lamellae-free-type pseudobranch of the euryhaline milkfish (Chanos chanos) is a Na+, K+-ATPase-abundant organ involved in hypoosmoregulation. Comp Biochem Physiol A Mol Integr Physiol 2014; 170:15-25. [PMID: 24389090 DOI: 10.1016/j.cbpa.2013.12.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 12/10/2013] [Accepted: 12/17/2013] [Indexed: 10/25/2022]
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18
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Effects of salinity on growth and ion regulation of juvenile alligator gar Atractosteus spatula. Comp Biochem Physiol A Mol Integr Physiol 2013; 169:44-50. [PMID: 24368134 DOI: 10.1016/j.cbpa.2013.12.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 12/06/2013] [Accepted: 12/12/2013] [Indexed: 11/23/2022]
Abstract
The alligator gar (Atractosteus spatula) is a primitive euryhaline fish, found primarily in estuaries and freshwater drainages associated with the northern Gulf of Mexico. The extent of its hypo-osmotic regulatory abilities is not well understood. In order to determine how salinity affects growth rates and ionic and osmoregulation, juvenile alligator gar (330 days after hatch; 185 g) were exposed to 4 different salinities (0, 8, 16, and 24 ppt) for a 30-day period. Specific growth rate, plasma osmolality and ion concentrations, gill and gastrointestinal tract Na(+), K(+)-ATPase activities, and drinking rate were compared. Juvenile alligator gar were able to tolerate hyperosmotic salinities up to 24 ppt for a 30 day period, albeit with decreased growth resulting largely from decreased food consumption. Plasma osmolality and ionic concentrations were elevated in hyperosmotic salinities, and drinking rates and gastrointestinal tract Na(+), K(+)-ATPase activities increased, particularly in the pyloric caeca, presumably the primary location of water absorption. Therefore, juvenile alligator gar<1 year of age are capable of prolonged exposure to hyperosmotic salinities, but, based on the inference of these data, require access to lower salinities for long-term survival.
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Environmental Regulation of Mitochondria-Rich Cells in Chalcalburnus tarichi (Pallas, 1811) During Reproductive Migration. J Membr Biol 2012; 246:183-8. [DOI: 10.1007/s00232-012-9518-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2012] [Accepted: 10/15/2012] [Indexed: 10/27/2022]
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20
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Hiroi J, McCormick SD. New insights into gill ionocyte and ion transporter function in euryhaline and diadromous fish. Respir Physiol Neurobiol 2012; 184:257-68. [PMID: 22850177 DOI: 10.1016/j.resp.2012.07.019] [Citation(s) in RCA: 166] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Revised: 07/19/2012] [Accepted: 07/20/2012] [Indexed: 11/29/2022]
Abstract
Teleost fishes are able to acclimatize to seawater by secreting excess NaCl by means of specialized "ionocytes" in the gill epithelium. Antibodies against Na(+)/K(+)-ATPase (NKA) have been used since 1996 as a marker for identifying branchial ionocytes. Immunohistochemistry of NKA by itself and in combination with Na(+)/K(+)/2Cl(-) cotransporter and CFTR Cl(-) channel provided convincing evidence that ionocytes are functional during seawater acclimation, and also revealed morphological variations in ionocytes among teleost species. Recent development of antibodies to freshwater- and seawater-specific isoforms of the NKA alpha-subunit has allowed functional distinction of ion absorptive and secretory ionocytes in Atlantic salmon. Cutaneous ionocytes of tilapia embryos serve as a model for branchial ionocytes, allowing identification of 4 types: two involved in ion uptake, one responsible for salt secretion and one with unknown function. Combining molecular genetics, advanced imaging techniques and immunohistochemistry will rapidly advance our understanding of both the unity and diversity of ionocyte function and regulation in fish osmoregulation.
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Affiliation(s)
- Junya Hiroi
- Department of Anatomy, St. Marianna University School of Medicine, 2-16-1 Sugao, Kawasaki 216-8511, Japan.
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21
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Christensen AK, Hiroi J, Schultz ET, McCormick SD. Branchial ionocyte organization and ion-transport protein expression in juvenile alewives acclimated to freshwater or seawater. ACTA ACUST UNITED AC 2012; 215:642-52. [PMID: 22279071 DOI: 10.1242/jeb.063057] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The alewife (Alosa pseudoharengus) is a clupeid that undergoes larval and juvenile development in freshwater preceding marine habitation. The purpose of this study was to investigate osmoregulatory mechanisms in alewives that permit homeostasis in different salinities. To this end, we measured physiological, branchial biochemical and cellular responses in juvenile alewives acclimated to freshwater (0.5 p.p.t.) or seawater (35.0 p.p.t.). Plasma chloride concentration was higher in seawater-acclimated than freshwater-acclimated individuals (141 mmol l(-1) vs 134 mmol l(-1)), but the hematocrit remained unchanged. In seawater-acclimated individuals, branchial Na(+)/K(+)-ATPase (NKA) activity was higher by 75%. Western blot analysis indicated that the abundance of the NKA α-subunit and a Na(+)/K(+)/2Cl(-) cotransporter (NKCC1) were greater in seawater-acclimated individuals by 40% and 200%, respectively. NKA and NKCC1 were localized on the basolateral surface and tubular network of ionocytes in both acclimation groups. Immunohistochemical labeling for the cystic fibrosis transmembrane conductance regulator (CFTR) was restricted to the apical crypt of ionocytes in seawater-acclimated individuals, whereas sodium/hydrogen exchanger 3 (NHE3) labeling was present on the apical surface of ionocytes in both acclimation groups. Ionocytes were concentrated on the trailing edge of the gill filament, evenly distributed along the proximal 75% of the filamental axis and reduced distally. Ionocyte size and number on the gill filament were not affected by salinity; however, the number of lamellar ionocytes was significantly lower in seawater-acclimated fish. Confocal z-series reconstructions revealed that mature ionocytes in seawater-acclimated alewives occurred in multicellular complexes. These complexes might reduce paracellular Na(+) resistance, hence facilitating Na(+) extrusion in hypo-osmoregulating juvenile alewives after seaward migration.
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Affiliation(s)
- A K Christensen
- Department of Biology, University of Massachusetts, Amherst, MA 01003, USA.
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22
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Tang CH, Hwang LY, Shen ID, Chiu YH, Lee TH. Immunolocalization of chloride transporters to gill epithelia of euryhaline teleosts with opposite salinity-induced Na+/K+-ATPase responses. FISH PHYSIOLOGY AND BIOCHEMISTRY 2011; 37:709-724. [PMID: 21336594 DOI: 10.1007/s10695-011-9471-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2010] [Accepted: 01/31/2011] [Indexed: 05/30/2023]
Abstract
Opposite patterns of branchial Na(+)/K(+)-ATPase (NKA) responses were found in euryhaline milkfish (Chanos chanos) and pufferfish (Tetraodon nigroviridis) upon salinity challenge. Because the electrochemical gradient established by NKA is thought to be the driving force for transcellular Cl(-) transport in fish gills, the aim of this study was to explore whether the differential patterns of NKA responses found in milkfish and pufferfish would lead to distinct distribution of Cl(-) transporters in their gill epithelial cells indicating different Cl(-) transport mechanisms. In this study, immunolocalization of various Cl(-) transport proteins, including Na(+)/K(+)/2Cl(-) cotransporter (NKCC), cystic fibrosis transmembrane conductance regulator (CFTR), anion exchanger 1 (AE1), and chloride channel 3 (ClC-3), were double stained with NKA, the basolateral marker of branchial mitochondrion-rich cells (MRCs), to reveal the localization of these transporter proteins in gill MRC of FW- or SW-acclimated milkfish and pufferfish. Confocal microscopic observations showed that the localization of these transport proteins in the gill MRCs of the two studied species were similar. However, the number of gill NKA-immunoreactive (IR) cells in milkfish and pufferfish exhibited to vary with environmental salinities. An increase in the number of NKA-IR cells should lead to the elevation of NKA activity in FW milkfish and SW pufferfish. Taken together, the opposite branchial NKA responses observed in milkfish and pufferfish upon salinity challenge could be attributed to alterations in the number of NKA-IR cells. Furthermore, the localization of these Cl(-) transporters in gill MRCs of the two studied species was identical. It depicted the two studied euryhaline species possess the similar Cl(-) transport mechanisms in gills.
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Affiliation(s)
- Cheng-Hao Tang
- Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan
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23
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Tang S, Lewis A, Sackville M, Nendick L, DiBacco C, Brauner C, Farrell A. Diel vertical distribution of early marine phase juvenile pink salmon (Oncorhynchus gorbuscha) and behaviour when exposed to salmon louse (Lepeophtheirus salmonis). CAN J ZOOL 2011. [DOI: 10.1139/z11-049] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We observed diel vertical migration patterns in juvenile pink salmon ( Oncorhynchus gorbuscha (Walbaum, 1792)) and tested the hypothesis that fish behaviour is altered by exposure to sea lice copepodids. Experiments involved replicated field deployments of a large (9 m) plankton column, which provided a vertical distribution enclosure under natural light and salinity conditions. Diel vertical distributions of juvenile pink salmon were observed during the first 3 weeks of seawater acclimation in both the presence and the absence of the ectoparasitic salmon louse ( Lepeophtheirus salmonis (Krøyer, 1838)). Immediately upon entering seawater, juvenile pink salmon preferred the top 1 m of the water column, but they moved significantly deeper down the vertical water column as seawater acclimation time increased. A significant diel migration pattern was observed, which involved a preference for the surface at night-time, compared with daytime. When fish in the column were exposed to L. salmonis copepodids for 3 h, 43%–62% of fish became infected, fish expanded their vertical distribution range, and significant changes in vertical distribution patterns were observed.
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Affiliation(s)
- S. Tang
- Department of Zoology, The University of British Columbia, 6270 University Boulevard, Vancouver, BC V6T 1Z4, Canada
- Centre for Aquaculture and Environmental Research, 4160 Marine Drive, West Vancouver, BC V7V 1N6, Canada
| | - A.G. Lewis
- Earth and Ocean Sciences, The University of British Columbia, 6339 Stores Road, Vancouver, BC V6T 1Z4, Canada
| | - M. Sackville
- Department of Zoology, The University of British Columbia, 6270 University Boulevard, Vancouver, BC V6T 1Z4, Canada
| | - L. Nendick
- Department of Zoology, The University of British Columbia, 6270 University Boulevard, Vancouver, BC V6T 1Z4, Canada
| | - C. DiBacco
- Fisheries and Oceans Canada, Bedford Institute of Oceanography, Ecosystem Research Division, P.O. Box 1006, Dartmouth, NS B2Y 4A2, Canada
| | - C.J. Brauner
- Department of Zoology, The University of British Columbia, 6270 University Boulevard, Vancouver, BC V6T 1Z4, Canada
| | - A.P. Farrell
- Department of Zoology, The University of British Columbia, 6270 University Boulevard, Vancouver, BC V6T 1Z4, Canada
- Centre for Aquaculture and Environmental Research, 4160 Marine Drive, West Vancouver, BC V7V 1N6, Canada
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Fridman S, Bron JE, Rana KJ. Ontogenetic changes in location and morphology of chloride cells during early life stages of the Nile tilapia Oreochromis niloticus adapted to fresh and brackish water. JOURNAL OF FISH BIOLOGY 2011; 79:597-614. [PMID: 21884103 DOI: 10.1111/j.1095-8649.2011.03043.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Ontogenetic changes in the location, size, density and morphology of chloride cells in the Nile tilapia Oreochromis niloticus adapted to fresh and brackish water are described using Na(+) /K(+) -ATPase immunohistochemistry, light microscopy (LM), scanning electron microscopy (SEM) and confocal scanning laser microscopy (CSLM). The pattern of chloride cell distribution changed during development under both treatments, with chloride cell density decreasing significantly from hatch to 7 days post-hatch, but appearing on the inner opercular area at 3 days post-hatch and increasing significantly thereafter (P < 0·05). Chloride cells were always denser in fresh- than in brackish-water larvae. In both treatments, chloride cells located on the outer operculum and tail showed a marked increase in size with age, but cells located on the abdominal epithelium of the yolk sac and the inner operculum showed a significant decrease in size (P < 0·05). Chloride cells from brackish-water adapted larvae from 1 day post-hatch onwards were always significantly larger (P < 0·05) than those from freshwater-adapted larvae. SEM revealed structural differences in chloride cell apical morphology according to environmental conditions. There appears to be clearly defined temporal staging of the appearance of adaptive mechanisms that confer an ability to cope with varying environmental conditions during early development.
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Affiliation(s)
- S Fridman
- Institute of Aquaculture, University of Stirling, FK9 4LA Scotland, UK.
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Hwang PP, Lee TH, Lin LY. Ion regulation in fish gills: recent progress in the cellular and molecular mechanisms. Am J Physiol Regul Integr Comp Physiol 2011; 301:R28-47. [PMID: 21451143 DOI: 10.1152/ajpregu.00047.2011] [Citation(s) in RCA: 299] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Fish encounter harsh ionic/osmotic gradients on their aquatic environments, and the mechanisms through which they maintain internal homeostasis are more challenging compared with those of terrestrial vertebrates. Gills are one of the major organs conducting the internal ionic and acid-base regulation, with specialized ionocytes as the major cells carrying out active transport of ions. Exploring the iono/osmoregulatory mechanisms in fish gills, extensive literature proposed several models, with many conflicting or unsolved issues. Recent studies emerged, shedding light on these issues with new opened windows on other aspects, on account of available advanced molecular/cellular physiological approaches and animal models. Respective types of ionocytes and ion transporters, and the relevant regulators for the mechanisms of NaCl secretion, Na(+) uptake/acid secretion/NH(4)(+) excretion, Ca(2+) uptake, and Cl(-) uptake/base secretion, were identified and functionally characterized. These new ideas broadened our understanding of the molecular/cellular mechanisms behind the functional modification/regulation of fish gill ion transport during acute and long-term acclimation to environmental challenges. Moreover, a model for the systematic and local carbohydrate energy supply to gill ionocytes during these acclimation processes was also proposed. These provide powerful platforms to precisely study transport pathways and functional regulation of specific ions, transporters, and ionocytes; however, very few model species were established so far, whereas more efforts are needed in other species.
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Affiliation(s)
- Pung-Pung Hwang
- Institute of Cellular and Organismic Biology, Academia Sinica, Nankang, Taipei 115, Taiwan.
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26
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Ghazilou A, Chenary F, Morovvati H, Zolgarneine H. Time course of saltwater adaptation in Spotted Scat (Scatophagus argus) (Pisces): A histomorphometric approach. ACTA ACUST UNITED AC 2011. [DOI: 10.1080/11250003.2010.491099] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Choi JH, Lee KM, Inokuchi M, Kaneko T. Morphofunctional modifications in gill mitochondria-rich cells of Mozambique tilapia transferred from freshwater to 70% seawater, detected by dual observations of whole-mount immunocytochemistry and scanning electron microscopy. Comp Biochem Physiol A Mol Integr Physiol 2011; 158:132-42. [DOI: 10.1016/j.cbpa.2010.09.019] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2010] [Revised: 09/27/2010] [Accepted: 09/28/2010] [Indexed: 10/19/2022]
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Monette MY, Yada T, Matey V, McCormick SD. Physiological, molecular, and cellular mechanisms of impaired seawater tolerance following exposure of Atlantic salmon, Salmo salar, smolts to acid and aluminum. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2010; 99:17-32. [PMID: 20483493 DOI: 10.1016/j.aquatox.2010.03.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2010] [Revised: 03/11/2010] [Accepted: 03/27/2010] [Indexed: 05/29/2023]
Abstract
We examined the physiological, molecular, and cellular mechanisms of impaired ion regulation in Atlantic salmon, Salmo salar, smolts following acute acid and aluminum (Al) exposure. Smolts were exposed to: control (pH 6.5, 3.4 micrpg l(-1) Al), acid and low Al (LAl: pH 5.4, 11 microg l(-1) Al), acid and moderate Al (MAl: pH 5.3, 42 microg l(-1) Al), and acid and high Al (HAl: pH 5.4, 56 microg l(-1) Al) for two and six days. At each time-point, smolts were sampled directly from freshwater treatment tanks and after a 24h seawater challenge. Exposure to acid/MAl and acid/HAl led to accumulation of gill Al, substantial alterations in gill morphology, reduced gill Na(+)/K(+)-ATPase (NKA) activity, and impaired ion regulation in both freshwater and seawater. Exposure to acid/MAl for six days also led to a decrease in gill mRNA expression of the apical Cl(-) channel (cystic fibrosis transmembrane conductance regulator I), increased apoptosis upon seawater exposure, an increase in the surface expression of mitochondria-rich cells (MRCs) within the filament epithelium of the gill, but reduced abundance of gill NKA-positive MRCs. By contrast, smolts exposed to acid and the lowest Al concentration exhibited minor gill Al accumulation, slight morphological modifications in the gill, and impaired seawater tolerance in the absence of a detectable effect on freshwater ion regulation. These impacts were accompanied by decreased cell proliferation, a slight increase in the surface expression of MRCs within the filament epithelium, but no impact on gill apoptosis or total MRC abundance was observed. However, MRCs in the gills of smolts exposed to acid/LAl exhibited morphological alterations including decreased size, staining intensity, and shape factor. We demonstrate that the seawater tolerance of Atlantic salmon smolts is extremely sensitive to acute exposure to acid and low levels of Al, and that the mechanisms underlying this depend on the time-course and severity of Al exposure. We propose that when smolts are exposed to acid and moderate to high Al concentrations, impaired seawater tolerance results from extensive gill Al accumulation, damage to the epithelium, reduced MRC and transport protein abundance, and a synergistic stimulation of apoptosis in the gill upon seawater exposure. When smolts are exposed to acid and low levels of Al, loss of seawater tolerance appears to be independent of these mechanisms and may result instead from a shift in the phenotype of MRCs present in the gill epithelium.
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Affiliation(s)
- Michelle Y Monette
- Organismic and Evolutionary Biology Program, University of Massachusetts, Amherst, MA 01003,
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Teranishi K, Kaneko T. Spatial, cellular, and intracellular localization of Na+/K+-ATPase in the sterically disposed renal tubules of Japanese eel. J Histochem Cytochem 2010; 58:707-19. [PMID: 20421593 DOI: 10.1369/jhc.2010.955492] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The kidney plays a crucial role in the regulation of water and ion balances in both freshwater and seawater fishes. However, the complicated structures of the kidney hamper comprehensive understanding of renal functions. In this study, to investigate the structure of sterically disposed renal tubules, we examined spatial, cellular, and intracellular localization of Na(+)/K(+)-ATPase in the kidney of the Japanese eel. The renal tubule was composed of the first (PT-I) and second (PT-II) segments of the proximal tubule and the distal tubule (DT), followed by the collecting ducts (CDs). Light microscopic immunocytochemistry detected Na(+)/K(+)-ATPase along the renal tubules and CD; however, the subcellular distribution of the Na(+)/K(+)-ATPase immunoreaction varied among different segments. Electron microscopic immunocytochemistry further revealed that Na(+)/K(+)-ATPase was distributed on the basal infoldings of PT-I, PT-II, and DT cells. Three-dimensional analyses showed that the renal tubules meandered in a random pattern through lymphoid tissues, and then merged into the CD, which was aligned linearly. Among the different segments, the DT and CD cells showed more-intense Na(+)/K(+)-ATPase immunoreaction in freshwater eel than in seawater-acclimated eel, confirming that the DT and CD segments are important in freshwater adaptation, or hyperosmoregulation.
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Affiliation(s)
- Keitaro Teranishi
- Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan.
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Leguen I, Odjo N, Le Bras Y, Luthringer B, Baron D, Monod G, Prunet P. Effect of seawater transfer on CYP1A gene expression in rainbow trout gills. Comp Biochem Physiol A Mol Integr Physiol 2010; 156:211-7. [PMID: 20167284 DOI: 10.1016/j.cbpa.2010.02.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2009] [Revised: 02/01/2010] [Accepted: 02/04/2010] [Indexed: 01/24/2023]
Abstract
During the transfer of rainbow trout from freshwater to seawater, the gills have to switch from an ion-absorption epithelium to an ion-secretion epithelium in order to maintain equilibrium of their hydromineral balance. After a change to ambient salinity, several gill modifications have already been demonstrated, including ion transporters. In order to identify new branchial mechanisms implicated in seawater acclimation, we carried out an extensive analysis of gene expression in gills using microarray technology. This strategy allowed us to show that CYP1A gene expression was up-regulated in the gills after salinity transfer. This increase was confirmed by real-time reverse transcription PCR. Furthermore, measurements of CYP1A enzyme activity (EROD) showed a significant increase after transfer to seawater. Immunohistochemistry analysis in the gills revealed that cells with a higher expression of CYP1A protein were principally pillar cells and those in the primary lamellae not in contact with the external medium. The results of this study suggest for the first time that CYP1A may be implicated in the seawater acclimation of the gills of rainbow trout.
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Affiliation(s)
- I Leguen
- INRA, UR1037, SCRIBE, IFR140, Biogenouest, F-35000, Rennes, France.
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31
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Ontogenic change in tissue osmolality and developmental sequence of mitochondria-rich cells in Mozambique tilapia developing in freshwater. Comp Biochem Physiol A Mol Integr Physiol 2009; 154:263-9. [DOI: 10.1016/j.cbpa.2009.06.025] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2009] [Revised: 06/24/2009] [Accepted: 06/24/2009] [Indexed: 11/20/2022]
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Allen PJ, Cech JJ, Kültz D. Mechanisms of seawater acclimation in a primitive, anadromous fish, the green sturgeon. J Comp Physiol B 2009; 179:903-20. [PMID: 19517116 PMCID: PMC2745624 DOI: 10.1007/s00360-009-0372-2] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2009] [Revised: 05/21/2009] [Accepted: 05/22/2009] [Indexed: 11/25/2022]
Abstract
Relatively little is known about salinity acclimation in the primitive groups of fishes. To test whether physiological preparative changes occur and to investigate the mechanisms of salinity acclimation, anadromous green sturgeon, Acipenser medirostris (Chondrostei) of three different ages (100, 170, and 533 dph) were acclimated for 7 weeks to three different salinities (<3, 10, and 33 ppt). Gill, kidney, pyloric caeca, and spiral intestine tissues were assayed for Na(+), K(+)-ATPase activity; and gills were analyzed for mitochondria-rich cell (MRC) size, abundance, localization and Na(+), K(+)-ATPase content. Kidneys were analyzed for Na(+), K(+)-ATPase localization and the gastro-intestinal tract (GIT) was assessed for changes in ion and base content. Na(+), K(+)-ATPase activities increased in the gills and decreased in the kidneys with increasing salinity. Gill MRCs increased in size and decreased in relative abundance with fish size/age. Gill MRC Na(+), K(+)-ATPase content (e.g., ion-pumping capacity) was proportional to MRC size, indicating greater abilities to regulate ions with size/age. Developmental/ontogenetic changes were seen in the rapid increases in gill MRC size and lamellar length between 100 and 170 dph. Na(+), K(+)-ATPase activities increased fourfold in the pyloric caeca in 33 ppt, presumably due to increased salt and water absorption as indicated by GIT fluids, solids, and ion concentrations. In contrast to teleosts, a greater proportion of base (HCO(3) (-) and 2CO(3) (2-)) was found in intestinal precipitates than fluids. Green sturgeon osmo- and ionoregulate with similar mechanisms to more-derived teleosts, indicating the importance of these mechanisms during the evolution of fishes, although salinity acclimation may be more dependent on body size.
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Affiliation(s)
- Peter J Allen
- Department of Wildlife, Fish, and Conservation Biology, University of California, 1 Shields Avenue, Davis, CA, 95616, USA.
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Madsen SS, Kiilerich P, Tipsmark CK. Multiplicity of expression of Na+,K+-ATPase {alpha}-subunit isoforms in the gill of Atlantic salmon (Salmo salar): cellular localisation and absolute quantification in response to salinity change. ACTA ACUST UNITED AC 2009; 212:78-88. [PMID: 19088213 DOI: 10.1242/jeb.024612] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The ability to reverse the net direction of gill ion transport in response to a salinity change is critical for euryhaline teleosts and involves a complex cellular and molecular remodelling of the gill epithelium. The present study aimed to clarify the cellular localisation and exact quantitative inter-relationship of Na(+),K(+)-ATPase alpha- and beta-subunit transcripts in Atlantic salmon gill during salinity change. The combined expression level of all alpha-isoforms in the gill increased by 100% after freshwater (FW) to seawater (SW) transfer. The alpha(1a) and alpha(1b) isoforms were both in the range 1-6 amol 20 ng(-1) total RNA; alpha(1a) decreased and alpha(1b) increased after SW-transfer, their ratio changing from 5:1 in FW to 0.26:1 in SW. The alpha(1c) and alpha(3) levels were 10- and 100-fold lower, respectively. The beta(1)-subunit mRNA level was 0.1-0.3 amol 20 ng(-1) total RNA, thus much lower than the sum of alpha-subunits. Even though increasing 3-fold after SW-transfer, beta-subunit availability may still limit functional pump synthesis. The mRNAs of the predominant alpha(1a) and alpha(1b) isoforms were localised by in situ hybridisation in specific gill cells of both FW and SW salmon. Labelling occurred mainly in presumed chloride cells and cells deep in the filament but occasionally also on lamellae. Overall, the salinity-induced variation in labelling pattern and intensity matched the quantification data. In conclusion, the predominant switching of Na(+),K(+)-ATPase alpha-subunit isoform mRNA during salinity acclimation reflects a marked remodelling of mitochondrion-rich cells (MRCs) in the gill and probably tuning of the pump performance to accomplish a net reversal of gill ion transport in hypo- and hypertonic environments.
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Affiliation(s)
- Steffen S Madsen
- Institute of Biology, University of Southern Denmark, 5230 Odense M, Denmark.
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Chang WJ, Horng JL, Yan JJ, Hsiao CD, Hwang PP. The transcription factor, glial cell missing 2, is involved in differentiation and functional regulation of H+-ATPase-rich cells in zebrafish (Danio rerio). Am J Physiol Regul Integr Comp Physiol 2009; 296:R1192-201. [PMID: 19193938 DOI: 10.1152/ajpregu.90973.2008] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
H(+)-ATPase-rich (HR) cells in zebrafish are known to be involved in acid secretion and Na(+) uptake mechanisms in zebrafish gills/skin; however, little is known about how HR cells are functionally regulated. In the present work, we studied the roles of Drosophila glial cell missing (gcm), a cell fate-related transcription factor, in the differentiation and functional regulation of zebrafish HR cells. Zebrafish gcm2 (zgcm2) was found to begin expression in zebrafish embryos at 10 h postfertilization (hpf), and to be extensively expressed in gills but only mildly so in eyes, heart, muscles, and testes. By whole mount in situ hybridization, zgcm2 mRNA signals were found in a group of cells on the zebrafish yolk sac surface initially in the tail bud stage (10 hpf); they had disappeared at 36 hpf and thereafter appeared again in the gill region from 48 hpf. Double fluorescence in situ hybridization further demonstrated specific colocalization of zgcm2 mRNA in HR cells in zebrafish embryos. Knockdown of zgcm2 with a specific morpholino oligonucleotide caused the complete disappearance of HR cells with a concomitant decrease in H(+) activity at the apical surface of HR cells, but it did not affect the occurrence of Na(+)-K(+)-ATPase-rich cells. A decrease in the H(+)-ATPase subunit A (zatp6v1a) expression and no change in zgcm2 expression in zebrafish gills were seen from 12 h to 3 days after transfer to acidic fresh water, but a compensatory stimulation in the expressions of both genes appeared 4 days post-transfer. In conclusion, functional regulation of HR cells is probably achieved by enhancing cell differentiation via zGCM2 activation.
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Affiliation(s)
- Wei-Jen Chang
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 11529, Taiwan
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Tang CH, Chang IC, Chen CH, Lee TH, Hwang PP. Phenotypic changes in mitochondrion-rich cells and responses of Na+/K+-ATPase in gills of tilapia exposed to deionized water. Zoolog Sci 2008; 25:205-11. [PMID: 18533752 DOI: 10.2108/zsj.25.205] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2007] [Accepted: 10/11/2007] [Indexed: 11/17/2022]
Abstract
The aim of this study was to illustrate the phenotypic modification of mitochondrion-rich (MR) cells and Na(+)/K(+)-ATPase (NKA) responses, including relative protein abundance, specific activity, and immunolocalization in gills of euryhaline tilapia exposed to deionized water (DW) for one week. The plasma osmolality was not significantly different between tilapia of the local fresh water (LFW) group and DW group. Remodeling of MR cells occurred in DW-exposed fish. After transfer to DW for one week, the relative percentage of subtype-I (wavy-convex) MR cells with apical size ranging from 3 to 9 microm increased and eventually became the dominant MR cell subtype. In DW tilapia gills, relative percentages of lamellar NKA immunoreactive (NKIR) cells among total NKIR cells increased to 29% and led to significant increases in the number of NKIR cells. In addition, the relative protein abundance and specific activity of NKA were significantly higher in gills of the DW-exposed fish. Our study concluded that tilapia require the development of subtype-I MR cells, the presence of lamellar NKIR cells, and enhancement of NKA protein abundance and activity in gills to deal with the challenge of an ion-deficient environment.
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Affiliation(s)
- Cheng-Hao Tang
- Department of Life Sciences, National Chung-Hsing University, Taichung, 402 Taiwan
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36
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Hwang PP, Lee TH. New insights into fish ion regulation and mitochondrion-rich cells. Comp Biochem Physiol A Mol Integr Physiol 2007; 148:479-97. [PMID: 17689996 DOI: 10.1016/j.cbpa.2007.06.416] [Citation(s) in RCA: 353] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2007] [Revised: 06/18/2007] [Accepted: 06/19/2007] [Indexed: 10/23/2022]
Abstract
Compared to terrestrial animals, fish have to cope with more-challenging osmotic and ionic gradients from aquatic environments with diverse salinities, ion compositions, and pH values. Gills, a unique and highly studied organ in research on fish osmoregulation and ionoregulation, provide an excellent model to study the regulatory mechanisms of ion transport. The present review introduces and discusses some recent advances in relevant issues of teleost gill ion transport and functions of gill ionocytes. Based on accumulating evidence, a conclusive model of NaCl secretion in gills of euryhaline teleosts has been established. Interpretations of results of studies on freshwater fish gill Na+/Cl- uptake mechanisms are still being debated compared with those for NaCl secretion. Current models for Na+/Cl- uptake are proposed based on studies in traditionally used model species. Many reported inconsistencies are claimed to be due to differences among species, various experimental designs, or acclimation conditions. Having the benefit of advanced techniques in molecular/cellular biology, functional genomics, and model animals, several new notions have recently been raised concerning relevant issues of Na+/Cl- uptake pathways. Several new windows have been opened particularly in terms of molecular mechanisms of ionocyte differentiation and energy metabolite transport between gill cells during environmental challenge.
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Affiliation(s)
- Pung-Pung Hwang
- Institute of Cellular and Organismic Biology, Academia Sinica, Nankang, Taipei, 115, Taiwan.
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Bystriansky JS, Frick NT, Richards JG, Schulte PM, Ballantyne JS. Wild Arctic Char (Salvelinus alpinus) Upregulate Gill Na+,K+‐ATPase during Freshwater Migration. Physiol Biochem Zool 2007; 80:270-82. [PMID: 17390283 DOI: 10.1086/512982] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/15/2007] [Indexed: 11/04/2022]
Abstract
The successful acclimation of eurhyhaline fishes from seawater to freshwater requires the gills to stop actively secreting ions and start actively absorbing ions. Gill Na(+),K(+)-ATPase is known to be an integral part of the active ion secretion model of marine fishes, but its importance in the active ion uptake model of freshwater fishes is less clear. This study, conducted in the high Arctic, examines gill Na(+),K(+)-ATPase regulation in wild anadromous arctic char returning to freshwater from the ocean. Gill Na(+),K(+)-ATPase activity, protein expression, and mRNA expression of Na(+),K(+)-ATPase isoforms alpha 1a and alpha 1b were monitored in arctic char at three points along their migration route to and from Somerset Island, Nunavut, Canada: out at sea (Whaler's Point), in seawater near the river mouth (Nat's Camp), and after entering the Union River. Arctic char collected from the Union River had more than twofold greater gill Na(+),K(+)-ATPase activity. This was associated with a significant increase (threefold) in Na(+),K(+)-ATPase isoform alpha 1a mRNA expression and a significant increase in plasma sodium and osmolality levels compared with seawater char. Compared with char sampled from Whaler's Point, Na(+),K(+)-ATPase isoform alpha 1b mRNA expression was decreased by approximately 50% in char sampled at Nat's Camp and the Union River. These results suggest that the upregulation of gill Na(+),K(+)-ATPase activity is involved in freshwater acclimation of arctic char and implicate a role for Na(+),K(+)-ATPase isoform alpha 1a in this process. In addition, we discuss evidence that arctic char go through a preparatory phase, or "reverse smoltification," before entering freshwater.
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Affiliation(s)
- J S Bystriansky
- Department of Integrative Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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38
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Hiroi J, McCormick SD. Variation in salinity tolerance, gill Na+/K+-ATPase,Na+/K+/2Cl– cotransporter and mitochondria-rich cell distribution in three salmonids Salvelinus namaycush, Salvelinus fontinalis and Salmo salar. J Exp Biol 2007; 210:1015-24. [PMID: 17337714 DOI: 10.1242/jeb.002030] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
We compared seawater tolerance, gill Na+/K+-ATPase and Na+/K+/2Cl– cotransporter (NKCC)abundance, and mitochondria-rich cell (MRC) morphology of three salmonids,lake trout Salvelinus namaycush, brook trout Salvelinus fontinalis and Atlantic salmon Salmo salar. They were transferred directly from 0 p.p.t. (parts per thousand; freshwater) to 30 p.p.t. seawater, or transferred gradually from 0 to 10, 20 and 30 p.p.t. at 1-week intervals and kept in 30 p.p.t. for 3 weeks. The survival rates of lake trout, brook trout and Atlantic salmon were 80%, 50% and 100% following direct transfer, and 80%, 100% and 100% during gradual transfer, respectively. Plasma Na+, K+ and Cl– concentrations in surviving lake trout increased rapidly and remained at high levels in 30 p.p.t. of both direct and gradual transfer, whereas those in brook trout showed a transient increase following direct transfer but did not change significantly during gradual transfer. Only minor changes in plasma ions were observed in Atlantic salmon smolts in both direct and gradual transfer. These results suggest that lake trout retains some degree of euryhalinity and that brook trout possesses intermediate euryhalinity between lake trout and Atlantic salmon smolts. Gill Na+/K+-ATPase activity of lake trout and brook trout increased in seawater, whereas that of Atlantic salmon smolts was already upregulated in freshwater and remained high after seawater exposure. NKCC abundance was upregulated in parallel with gill Na+/K+-ATPase activity in each species. Immunocytochemistry with anti-Na+/K+-ATPaseα-subunit and anti-NKCC revealed that the two ion transporters were colocalized on the basolateral membrane of gill MRCs. Immunopositive MRCs were distributed on both primary filaments and secondary lamellae in all three species kept in freshwater; following transfer to seawater this pattern did not change in lake trout and brook trout but lamellar MRCs disappeared in Atlantic salmon. Previous studies on several teleost species have suggested that filament and lamellar MRCs would be involved in seawater and freshwater acclimation, respectively. However, our results in lake trout and brook trout suggest that lamellar MRCs could be also functional during seawater acclimation.
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Affiliation(s)
- Junya Hiroi
- USGS, Conte Anadromous Fish Research Center, Turners Falls, MA 01376, USA.
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Tipsmark CK, Luckenbach JA, Madsen SS, Borski RJ. IGF-I and branchial IGF receptor expression and localization during salinity acclimation in striped bass. Am J Physiol Regul Integr Comp Physiol 2007; 292:R535-43. [PMID: 16959864 DOI: 10.1152/ajpregu.00915.2005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The initial response of the IGF-I system and the expression and cellular localization of IGF type-I receptor (IGF-IR) were studied in the gill of a euryhaline teleost during salinity acclimation. Exposure of striped bass ( Morone saxatilis) to hyperosmotic and hypoosmotic challenges induced small, transitory (<24 h) deflections in hydromineral balance. Transfer from freshwater (FW) to seawater (SW) induced an initial decrease in plasma IGF-I levels after 24 h in both fed and fasted fish. There was an overall decrease in liver IGF-I mRNA levels after SW transfer, suggesting that decreased plasma levels may be due to a decline in hepatic IGF-I synthesis. No changes were observed in gill IGF-I mRNA, but SW transfer induced an increase in gill IGF-IR mRNA after 24 h. Transfer from SW to FW induced an increase in plasma IGF-I levels in fasted fish. In fed fish, no significant changes were observed in either plasma IGF-I, liver, or gill IGF-I mRNA, or gill IGF-IR mRNA levels. In a separate experiment, FW-acclimated fish were injected with saline or IGF-I prior to a 24-h SW challenge. Rapid regain of osmotic balance following SW transfer was hindered by IGF-I. Immunohistochemistry revealed for the first time in teleosts that IGF-IR and Na+-K+-ATPase are localized in putative chloride cells at the base of the lamellae, identifying these cells in the gill as a target for IGF-I and IGF-II. Overall the data suggest a hyperosmoregulatory role of IGF-I in this species.
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Lee KM, Kaneko T, Katoh F, Aida K. Prolactin gene expression and gill chloride cell activity in fugu Takifugu rubripes exposed to a hypoosmotic environment. Gen Comp Endocrinol 2006; 149:285-93. [PMID: 16884723 DOI: 10.1016/j.ygcen.2006.06.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2006] [Revised: 06/15/2006] [Accepted: 06/18/2006] [Indexed: 11/15/2022]
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Lee KM, Kaneko T, Aida K. Prolactin and prolactin receptor expressions in a marine teleost, pufferfish Takifugu rubripes. Gen Comp Endocrinol 2006; 146:318-28. [PMID: 16430892 DOI: 10.1016/j.ygcen.2005.12.003] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2005] [Revised: 11/23/2005] [Accepted: 12/02/2005] [Indexed: 11/17/2022]
Abstract
To investigate the physiological significance of prolactin (PRL) in a marine teleost, pufferfish (or fugu), Takifugu rubripes, we cloned and characterized cDNAs encoding its PRL and PRL receptor (PRLR) from the pituitary and gills, respectively. The fugu PRL cDNA consisted of 995 bp and encoded a protein of 213 amino acids. The PRLR, consisting of 510 amino acids, contained a putative signal peptide, an extracellular domain with two pairs of cysteines, a WSXWS motif, a single transmembrane domain, and a cytoplasmic (intracellular) domain with box 1 and box 2 regions, all of which are characteristic of the cytokine receptor superfamily. Reverse transcription-PCR showed the expression of PRLR mRNA in osmoregulatory organs, such as gills, kidney, and intestine, whereas pufferfish PRL mRNA was detected only in the pituitary. Furthermore, in situ hybridization revealed the expression of pufferfish PRLR in branchial chloride cells, kidney tubule cells, and intestinal epithelia. The PRL-gene expression levels in the pituitary were about five times higher in 25%-diluted seawater than in full-strength seawater. These results suggest that fugu PRL regulates water and electrolyte balances through PRLR expressed in the osmoregulatory organs, as is the case with freshwater-adapted euryhaline species.
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Affiliation(s)
- Kyung Mi Lee
- Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo 113-8657, Japan.
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42
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Takahashi H, Sakamoto T, Hyodo S, Shepherd BS, Kaneko T, Grau EG. Expression of glucocorticoid receptor in the intestine of a euryhaline teleost, the Mozambique tilapia (Oreochromis mossambicus): Effect of seawater exposure and cortisol treatment. Life Sci 2006; 78:2329-35. [PMID: 16376384 DOI: 10.1016/j.lfs.2005.09.050] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2005] [Accepted: 09/20/2005] [Indexed: 11/21/2022]
Abstract
Cortisol plays an important role in controlling intestinal water and ion transport in teleosts possibly through glucocorticoid receptor (GR) and/or mineralocorticoid receptor. To better understand the role of GR in the teleost intestine, in a euryhaline tilapia, Oreochromis mossambicus, we examined (1) the intestinal localizations of GR; (2) the effects of environmental salinity challenge and cortisol treatment on GR mRNA expression. The mRNA abundance of GR in the posterior intestinal region of tilapia was found to be higher than that in the anterior and middle intestine. In the posterior intestine, GR appears to be localized in the mucosal layer. GR mRNA levels in the posterior intestine were elevated after exposure of freshwater fish to seawater for 7 days following an increase in plasma cortisol. Similarly, cortisol implantation in freshwater tilapia for 7 days elevated the intestinal GR mRNA. These results indicate that seawater acclimation is accompanied by upregulation of GR mRNA abundance in intestinal tissue, possibly as a consequence of the elevation of cortisol levels. In contrast, a single intraperitoneal injection of cortisol into freshwater tilapia decreased intestinal GR mRNA. This downregulation of the GR mRNA by cortisol suggests a dual mode of autoregulation of GR expression by cortisol.
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Affiliation(s)
- Hideya Takahashi
- Ushimado Marine Laboratory, Graduate School of Natural Science and Technology, Okayama University, Ushimado, Setouchi, Okayama, 701-4303, Japan
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Lin YM, Chen CN, Yoshinaga T, Tsai SC, Shen ID, Lee TH. Short-term effects of hyposmotic shock on Na+/K+-ATPase expression in gills of the euryhaline milkfish, Chanos chanos. Comp Biochem Physiol A Mol Integr Physiol 2006; 143:406-15. [PMID: 16459117 DOI: 10.1016/j.cbpa.2005.12.031] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2005] [Revised: 12/21/2005] [Accepted: 12/21/2005] [Indexed: 10/25/2022]
Abstract
Changes in expression of gill Na+/K+ -ATPase (NKA) on a short-term (96 h) time-course following hyposmotic shock (direct transfer to fresh water) of the euryhaline, marine milkfish were studied on gene, protein, and cell levels in this paper. Plasma osmolality and [Na+] responded with rapid declines in 3 h post-transfer yet, thereafter, remained constant. Plasma [Cl-] gradually fell to a significantly lower level at 6 h post-transfer. Gills responded to hyposmotic shock by a dual phase enhancement of NKA activity and protein abundance; (a) Before 24 h: NKA activity increased as early as 3 h and reached a maximum level from 6 to 12 h post-transfer coincided with the sustained lower levels of plasma osmolality, [Na+], and [Cl-] since 3 h post-transfer. This was followed by a gradual rise in alpha-subunit protein levels that peaked at 12 h post-transfer. Meanwhile, alpha-mRNA of NKA did no show significant change. (b) After 24 h: NKA activity as well as the amounts of alpha-subunit mRNA and protein increased significantly. Direct freshwater transfer induced a prompt and significant decrease of NKA immunoreactive (NKIR) cell abundance in filaments before 24 h, followed by a significant increase after 24 h due to their development in filaments and lamellae. Increased number of NKIR cells after 24 h of hyposmotic shock may occur in conjunction with rise of NKA activity as well as alpha-subunit mRNA and protein abundance. In conclusion, milkfish is able to avoid an excessive drop in plasma ions immediately upon hyposmotic shock and maintain plasma ions on a marginal lower level in fresh water. Notably, the initial increase in NKA activity (adjustive phase; 3-12 h) and delayed increase in NKA mRNA and protein abundance (regulatory phase; 48-96 h) indicate the importance of a higher level of the gill enzyme in milkfish upon hyposmotic shock.
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Affiliation(s)
- Y M Lin
- Department of Life Sciences, National Chung-Hsing University, Taichung 402, Taiwan
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44
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Shivkamat P, Roy R. Regulation of membrane lipid bilayer structure during salinity adaptation: a study with the gill epithelial cell membranes of Oreochromis niloticus. Comp Biochem Physiol B Biochem Mol Biol 2005; 142:28-36. [PMID: 16000254 DOI: 10.1016/j.cbpc.2005.05.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2004] [Revised: 05/10/2005] [Accepted: 05/10/2005] [Indexed: 10/25/2022]
Abstract
A significant variation in the membrane fluidity (as assessed by DPH-fluorescence polarisation) and membrane lipid bilayer composition is noticed in the subcellular membranes of the gill epithelial cells of Oreochromis niloticus due to exposure of the fish to 1% saline water for 1 month. Also, a 70% enhanced activity of Na(+)-K(+)-ATPase in plasma membranes and a 2.5-fold increase of glucose-6-phosphate dehydrogenase in microsomal membranes are recorded in the treated fish. The changed membrane structure and fluidity along with the changed enzymatic activity of Na(+)-K(+)-ATPase help the influx the Na(+) rather than the efflux of K(+) through the gill epithelial cells during salinity adaptation.
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Affiliation(s)
- P Shivkamat
- Department of Zoology, Goa University, Taleigao, Panaji, Goa.403206, India
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Nebel C, Romestand B, Nègre-Sadargues G, Grousset E, Aujoulat F, Bacal J, Bonhomme F, Charmantier G. Differential freshwater adaptation in juvenile sea-bassDicentrarchus labrax: involvement of gills and urinary system. J Exp Biol 2005; 208:3859-71. [PMID: 16215214 DOI: 10.1242/jeb.01853] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARYThe effects of long-term freshwater acclimatization were investigated in juvenile sea-bass Dicentrarchus labrax to determine whether all sea-bass juveniles are able to live in freshwater and to investigate the physiological basis of a successful adaptation to freshwater. This study particularly focused on the ability of sea-bass to maintain their hydromineral balance in freshwater and on their ion (re)absorbing abilities through the gills and kidneys. Two different responses were recorded after a long-term freshwater acclimatization. (1) Successfully adapted sea-bass displayed standard behavior; their blood osmolality was maintained almost constant after the freshwater challenge, attesting to their efficient hyperosmoregulation. Their branchial and renal Na+/K+-ATPase abundance and activity were high compared to seawater fish due to a high number of branchial ionocytes and to the involvement of the urinary system in active ion reabsorption, producing hypotonic urine. (2) Sea-bass that had not successfully adapted to freshwater were recognized by abnormal schooling behavior. Their blood osmolality was low (30% lower than in the successfully adapted sea-bass), which is a sign of acute osmoregulatory failure. High branchial Na+/K+-ATPase abundance and activity compared to successfully adapted fish were coupled to a proliferation of gill chloride cells, whose ultrastructure did not display pathological signs. The large surface used by the gill chloride cells might negatively interfere with respiratory gas exchanges. In their urinary system, enzyme abundance and activity were low, in accordance with the observed lower density of the kidney tubules. Urine was isotonic to blood in unsuccessfully adapted fish, ruling out any participation of the kidney in hyperosmoregulation. The kidney failure seems to generate a compensatory ion absorption through increased gill activity, but net ion loss through urine seems higher than ion absorption by the gills, leading to lower hyper-osmoregulatory performance and to death.
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Affiliation(s)
- Catherine Nebel
- Laboratoire Génome, Populations, Interactions, Adaptation, UMR 5171, Université Montpellier II, Place E. Bataillon, 34095 Montpellier, Cedex 05, France.
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Martínez-Alvarez RM, Sanz A, García-Gallego M, Domezain A, Domezain J, Carmona R, del Valle Ostos-Garrido M, Morales AE. Adaptive branchial mechanisms in the sturgeon Acipenser naccarii during acclimation to saltwater. Comp Biochem Physiol A Mol Integr Physiol 2005; 141:183-90. [PMID: 15955717 DOI: 10.1016/j.cbpb.2005.05.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2004] [Revised: 05/05/2005] [Accepted: 05/06/2005] [Indexed: 10/25/2022]
Abstract
Variations of Na(+)/K(+)-ATPase activity and fatty-acid composition in the gills of the sturgeon Acipenser naccarii subjected to progressive acclimation to full seawater (35 ppt) were determined in relation to the hypo-osmoregulatory capacity of this species in the hyperosmotic medium. Blood samples were taken and gills arches were removed at intermediate salinity levels between 0 and 35 ppt and after 20 days at constant salinity (35 ppt). Plasma osmolality and Na(+)/K(+)-ATPase activity increased significantly with growing environmental salinity. Total saturated fatty acids (SFAs) decreased, while total polyunsaturated fatty acids (PUFAs) increased significantly with increasing salinity due mainly to changes in n-3 PUFAs (20:5n-3 and 22:6n-3). The n-3/n-6 ratio increased significantly during the acclimation process. The results show a direct relationship between salinity, increased gill Na(+)/K(+)-ATPase activity and ultrastructural changes of the gill chloride cells. Changes in the fatty-acid composition in gills of A. naccarii during progressive acclimation to full seawater suggest that variations of gill fatty acids may also have a role in osmoregulatory mechanisms.
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Ebbesson LOE, Tipsmark CK, Holmqvist B, Nilsen T, Andersson E, Stefansson SO, Madsen SS. Nitric oxide synthase in the gill of Atlantic salmon: colocalization with and inhibition of Na+,K+-ATPase. J Exp Biol 2005; 208:1011-7. [PMID: 15767302 DOI: 10.1242/jeb.01488] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
We investigated the relationship between nitric oxide (NO) and Na+,K+-ATPase (NKA) in the gill of anadromous Atlantic salmon. Cells containing NO-producing enzymes were revealed by means of nitric oxide synthase (NOS) immunocytochemistry and nicotinamide adenine dinucleotide phosphate diaphorase (NADPHd) histochemistry, which can be used as an indicator of NOS activity, i.e. NO production. Antibodies against the two constitutive NOS isoforms, neuronal and endothelial NOS, both produced immunoreactivity restricted to large cells at the base and along the secondary lamellae. NADPHd-positive cells showed a corresponding distribution. Antibodies against the inducible NOS isoform only labeled small cells located deep in the filament. Using in situ hybridization and NKA immunoreactivity, cells expressing Na+,K+-ATPaseα-subunit mRNA were found to have a similar distribution to the NOS cells. Double labeling for NOS immunoreactivity and NKA α-subunit mRNA revealed cellular colocalization of NKA α-subunit mRNA and nNOS protein in putative chloride cells at the base of the lamellae and interlamellar space. Along the lamellae, some NOS- or NKA-immunoreactive cells possessed a relatively lower expression of NKA α-subunit mRNA in smolts. A clear increase in NADPHd staining in the gill was demonstrated from parr to smolt. The regulatory role of NO on gill NKA activity was studied in vitrousing sodium nitroprusside (SNP; 1 mmol l-1) and PAPA-NONOate(NOC-15; 0.5 mmol l-1) as NO donors. Both SNP and NOC-15 inhibited gill NKA activity by 30% when compared to controls. The study shows that NO systems are abundant in the gill of Atlantic salmon, that NO may be produced preferentially by a constitutive NOS isoform, and suggests that NO influence on gill functions is mediated via intracellular, possibly both auto/paracrine,inhibition of Na+,K+-ATPase activity in chloride cells. Furthermore, the increase in NADPHd in the gill during smoltification suggests a regulatory role of NO in the attenuation of the smoltification-related increase in Na+,K+-ATPase activity prior to entering seawater.
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Affiliation(s)
- Lars O E Ebbesson
- Department of Biology, University of Bergen, Bergen High Technology Centre, N-5020 Bergen, Norway.
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Brauer PR, Sanmann JN, Petzel DH. Effects of warm acclimation on Na+,K+-ATPase α-subunit expression in chloride cells of Antarctic fish. ACTA ACUST UNITED AC 2005; 285:600-9. [PMID: 15912523 DOI: 10.1002/ar.a.20203] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The teleosts Trematomus bernacchii thrive in southern oceanic waters with temperatures below 0 degrees C. These fish have serum osmolalities almost double those found in fish of temperate waters, thereby lowering their serum's freezing point and the energy needed for ionic homeostasis. Upon warm acclimation to 4 degrees C, T. bernacchii decrease their serum osmolality and increase the Na+,K+-ATPase activity in their gills. Na+,K+-ATPase alpha1-, alpha2-, and alpha3-subunit isoforms are expressed in the gills of T. bernacchii and it is thought that Na+,K+-ATPase subunit composition in chloride cells changes with warm acclimation. Using immunohistochemistry, we compared the number of chloride cells expressing various alpha-isoforms of the Na+,K+-ATPase in the gills of cold- and warm-acclimated T. bernacchii. We found no change in the number of alpha2- or alpha3-immunopositive cells in warm-acclimated fish gills or in the number of cells immunopositive for the Na+,K+,2Cl- cotransporter. However, the number of pan-alpha-immunopositive (recognizing all three alpha-isoforms) and alpha1-immunopositive cells both increased in warm-acclimated fish. This suggests that changes in the number of alpha1-isoform-expressing chloride cells could contribute to the increased Na+,K+-ATPase activity that occurs with warm-acclimation.
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Affiliation(s)
- Philip R Brauer
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, Nebraska 68178, USA.
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Evans DH, Piermarini PM, Choe KP. The Multifunctional Fish Gill: Dominant Site of Gas Exchange, Osmoregulation, Acid-Base Regulation, and Excretion of Nitrogenous Waste. Physiol Rev 2005; 85:97-177. [PMID: 15618479 DOI: 10.1152/physrev.00050.2003] [Citation(s) in RCA: 1569] [Impact Index Per Article: 82.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The fish gill is a multipurpose organ that, in addition to providing for aquatic gas exchange, plays dominant roles in osmotic and ionic regulation, acid-base regulation, and excretion of nitrogenous wastes. Thus, despite the fact that all fish groups have functional kidneys, the gill epithelium is the site of many processes that are mediated by renal epithelia in terrestrial vertebrates. Indeed, many of the pathways that mediate these processes in mammalian renal epithelial are expressed in the gill, and many of the extrinsic and intrinsic modulators of these processes are also found in fish endocrine tissues and the gill itself. The basic patterns of gill physiology were outlined over a half century ago, but modern immunological and molecular techniques are bringing new insights into this complicated system. Nevertheless, substantial questions about the evolution of these mechanisms and control remain.
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Affiliation(s)
- David H Evans
- Department of Zoology, University of Florida, Gainesville 32611, USA.
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Lin CH, Tsai RS, Lee TH. Expression and distribution of Na, K-ATPase in gill and kidney of the spotted green pufferfish, Tetraodon nigroviridis, in response to salinity challenge. Comp Biochem Physiol A Mol Integr Physiol 2004; 138:287-95. [PMID: 15313482 DOI: 10.1016/j.cbpb.2004.04.005] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2003] [Revised: 02/14/2004] [Accepted: 04/10/2004] [Indexed: 11/30/2022]
Abstract
Freshwater (FW) spotted green pufferfish (Tetraodon nigroviridis) were transferred directly from a local aquarium to fresh water (FW; 0 per thousand ), brackish water (BW; 15 per thousand ), and seawater (SW; 35 per thousand ) conditions in the laboratory and reared for at least two weeks. No mortality was found. To investigate the efficient mechanisms of osmoregulation in the euryhaline teleost, distribution and expression of Na,K-ATPase (NKA) in gill and kidney of the pufferfish were examined and the osmolality, [Na+] and [Cl-] of the blood were assayed. The lowest levels of both relative protein abundance and activity were found to be exhibited in the BW group, and higher levels in the SW group than FW group. In all salinities, branchial NKA immunoreactivity was found in epithelial cells of the interlamellar region of the filament and not on the lamellae. Relative abundance of kidney NKA alpha-subunit, as well as the NKA activity, was found to be higher in the FW pufferfish than fish in BW or SW. Renal NKA appeared in the epithelial cells of distal tubules, proximal tubules, and collecting tubules, but not in glomeruli, in fish groups of various salinities. Plasma osmolality and chloride levels were significantly lower in FW pufferfish than those in BW and SW, whereas plasma sodium did not differ among the groups. Although identical distributions of NKA were found in either gill or kidney of FW-, BW- or SW-acclimated spotted green pufferfish, differential NKA expression in fish of various salinity groups was associated with physiological homeostasis (stable blood osmolality), and illustrated the impressive osmoregulatory ability of this freshwater and estuarine species in response to salinity challenge.
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Affiliation(s)
- C H Lin
- Department of Life Sciences, National Chung-Hsing University, Taichung 402, Taiwan
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