1
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Kovac A, Goss GG. Cellular mechanisms of ion and acid-base regulation in teleost gill ionocytes. J Comp Physiol B 2024:10.1007/s00360-024-01560-6. [PMID: 38761226 DOI: 10.1007/s00360-024-01560-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Revised: 04/16/2024] [Accepted: 04/27/2024] [Indexed: 05/20/2024]
Abstract
The mechanism(s) of sodium, chloride and pH regulation in teleost fishes has been the subject of intense interest for researchers over the past 100 years. The primary organ responsible for ionoregulatory homeostasis is the gill, and more specifically, gill ionocytes. Building on the theoretical and experimental research of the past, recent advances in molecular and cellular techniques in the past two decades have allowed for substantial advances in our understanding of mechanisms involved. With an increased diversity of teleost species and environmental conditions being investigated, it has become apparent that there are multiple strategies and mechanisms employed to achieve ion and acid-base homeostasis. This review will cover the historical developments in our understanding of the teleost fish gill, highlight some of the recent advances and conflicting information in our understanding of ionocyte function, and serve to identify areas that require further investigation to improve our understanding of complex cellular and molecular machineries involved in iono- and acid-base regulation.
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Affiliation(s)
- Anthony Kovac
- Department of Biological Sciences, University of Alberta, Edmonton, AB, T6G 2E9, Canada
| | - Greg G Goss
- Department of Biological Sciences, University of Alberta, Edmonton, AB, T6G 2E9, Canada.
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2
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Nan Y, Xiao M, Duan Y, Yang Y. Toxicity of Ammonia Stress on the Physiological Homeostasis in the Gills of Litopenaeus vannamei under Seawater and Low-Salinity Conditions. BIOLOGY 2024; 13:281. [PMID: 38666893 PMCID: PMC11048301 DOI: 10.3390/biology13040281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2024] [Revised: 04/19/2024] [Accepted: 04/19/2024] [Indexed: 04/28/2024]
Abstract
Ammonia is a major water quality factor influencing the survival and health of shrimp, among which the gill is the main effector organ for ammonia toxicity. In this study, we chose two types of Litopenaeus vannamei that were cultured in 30‱ seawater and domesticated in 3‱ low salinity, respectively, and then separately subjected to ammonia stress for 14 days under seawater and low-salinity conditions, of which the 3‱ low salinity-cultured shrimp were domesticated from the shrimp cultured in 30‱ seawater after 27 days of gradual salinity desalination. In detail, this study included four groups, namely the SC group (ammonia-N 0 mg/L, salinity 30‱), SAN group (ammonia-N 10 mg/L, salinity 30‱), LC group (ammonia-N 0 mg/L, salinity 3‱), and LAN group (ammonia-N 10 mg/L, salinity 3‱). The ammonia stress lasted for 14 days, and then the changes in the morphological structure and physiological function of the gills were explored. The results show that ammonia stress caused the severe contraction of gill filaments and the deformation or even rupture of gill vessels. Biochemical indicators of oxidative stress, including LPO and MDA contents, as well as T-AOC and GST activities, were increased in the SAN and LAN groups, while the activities of CAT and POD and the mRNA expression levels of antioxidant-related genes (nrf2, cat, gpx, hsp70, and trx) were decreased. In addition, the mRNA expression levels of the genes involved in ER stress (ire1 and xbp1), apoptosis (casp-3, casp-9, and jnk), detoxification (gst, ugt, and sult), glucose metabolism (pdh, hk, pk, and ldh), and the tricarboxylic acid cycle (mdh, cs, idh, and odh) were decreased in the SAN and LAN groups; the levels of electron-transport chain-related genes (ndh, cco, and coi), and the bip and sdh genes were decreased in the SAN group but increased in the LAN group; and the level of the ATPase gene was decreased but the cytc gene was increased in the SAN and LAN groups. The mRNA expression levels of osmotic regulation-related genes (nka-β, ca, aqp and clc) were decreased in the SAN group, while the level of the ca gene was increased in the LAN group; the nka-α gene was decreased in both two groups. The results demonstrate that ammonia stress could influence the physiological homeostasis of the shrimp gills, possibly by damaging the tissue morphology, and affecting the redox, ER function, apoptosis, detoxification, energy metabolism, and osmoregulation.
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Affiliation(s)
- Yuxiu Nan
- Ocean College, Hebei Agricultural University, Qinhuangdao 066003, China
- Key Laboratory of South China Sea Fishery Resources Exploitation & Utilization, Ministry of Agriculture and Rural Affairs, State Key Laboratory of Mariculture Biobreeding and Sustainable Goods, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300, China
| | - Meng Xiao
- Ocean College, Hebei Agricultural University, Qinhuangdao 066003, China
- Key Laboratory of South China Sea Fishery Resources Exploitation & Utilization, Ministry of Agriculture and Rural Affairs, State Key Laboratory of Mariculture Biobreeding and Sustainable Goods, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300, China
| | - Yafei Duan
- Key Laboratory of South China Sea Fishery Resources Exploitation & Utilization, Ministry of Agriculture and Rural Affairs, State Key Laboratory of Mariculture Biobreeding and Sustainable Goods, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300, China
- Key Laboratory of Efficient Utilization and Processing of Marine Fishery Resources of Hainan Province, Sanya Tropical Fisheries Research Institute, Sanya 572018, China
| | - Yukai Yang
- Key Laboratory of South China Sea Fishery Resources Exploitation & Utilization, Ministry of Agriculture and Rural Affairs, State Key Laboratory of Mariculture Biobreeding and Sustainable Goods, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300, China
- Shenzhen Base of South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shenzhen 518121, China
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3
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Nan Y, Zhu X, Huang J, Zhang Z, Xing Y, Yang Y, Xiao M, Duan Y. Toxic effects of triclocarban on the histological morphology, physiological and immune response in the gills of the black tiger shrimp Penaeus monodon. MARINE ENVIRONMENTAL RESEARCH 2023; 192:106245. [PMID: 37926588 DOI: 10.1016/j.marenvres.2023.106245] [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: 07/04/2023] [Revised: 09/21/2023] [Accepted: 10/24/2023] [Indexed: 11/07/2023]
Abstract
Triclocarban (TCC) is a widely used broad-spectrum antimicrobial agent that has become a pollutant threatening the health of aquatic animals. However, the toxic effects of TCC on Penaeus monodon are still lacking. In this study, we exposed P. monodon to 1 μg/L (TCC-1) and 10 μg/L TCC (TCC-10) for 14 days, and the changes of histological morphology, physiological and immune responses in the gills were investigated. The results showed that TCC exposure caused the deformation of the gill vessels and the disordered arrangement of the gill filaments. Oxidative stress biochemical indexes such as H2O2 content, CAT and GPx activity and the relative expression levels of antioxidant-related genes (SOD, GPx and Nrf2) were increased in the TCC-1 and TCC-10 groups; the levels of CAT and HSP70 genes were increased but POD activity was decreased in the TCC-10 group. The relative expression levels of endoplasmic reticulum (ER) stress indexes such as ERP15 and ATF-6 genes were increased in the TCC-10 group, while the level of GRP78 gene was decreased in the TCC-1 and TCC-10 groups. The relative expression levels of apoptosis indexes such as p53 and JNK genes were increased, but CytC and Casp-3 genes were decreased in the TCC-1 and TCC-10 groups. Furthermore, the relative expression levels of detoxification metabolism-related genes (cytP450 and GST) and osmotic regulation-related genes (NKA-α, NKA-β, CA, AQP, CLC and CCP) were increased in the TCC-10 group. The results showed that TCC exposure could affect the physiological homeostasis in the gills of P. monodon, probably via damaging histological morphology, inducing oxidative stress, and disordering ER stress, apoptosis, detoxification and osmotic regulation.
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Affiliation(s)
- Yuxiu Nan
- Key Laboratory of South China Sea Fishery Resources Exploitation & Utilization, Ministry of Agriculture and Rural Affairs, Guangdong Provincial Key Laboratory of Fishery Ecology and Environment, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, 510300, PR China; College of Marine Science, Hebei Agricultural University, Qinhuangdao, 066000, PR China
| | - Xuanyi Zhu
- Key Laboratory of South China Sea Fishery Resources Exploitation & Utilization, Ministry of Agriculture and Rural Affairs, Guangdong Provincial Key Laboratory of Fishery Ecology and Environment, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, 510300, PR China
| | - Jianhua Huang
- Shenzhen Base of South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shenzhen, 518121, PR China
| | - Zhe Zhang
- Key Laboratory of South China Sea Fishery Resources Exploitation & Utilization, Ministry of Agriculture and Rural Affairs, Guangdong Provincial Key Laboratory of Fishery Ecology and Environment, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, 510300, PR China
| | - Yifu Xing
- Key Laboratory of South China Sea Fishery Resources Exploitation & Utilization, Ministry of Agriculture and Rural Affairs, Guangdong Provincial Key Laboratory of Fishery Ecology and Environment, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, 510300, PR China
| | - Yukai Yang
- Key Laboratory of South China Sea Fishery Resources Exploitation & Utilization, Ministry of Agriculture and Rural Affairs, Guangdong Provincial Key Laboratory of Fishery Ecology and Environment, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, 510300, PR China; Shenzhen Base of South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shenzhen, 518121, PR China
| | - Meng Xiao
- Key Laboratory of South China Sea Fishery Resources Exploitation & Utilization, Ministry of Agriculture and Rural Affairs, Guangdong Provincial Key Laboratory of Fishery Ecology and Environment, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, 510300, PR China; College of Marine Science, Hebei Agricultural University, Qinhuangdao, 066000, PR China
| | - Yafei Duan
- Key Laboratory of South China Sea Fishery Resources Exploitation & Utilization, Ministry of Agriculture and Rural Affairs, Guangdong Provincial Key Laboratory of Fishery Ecology and Environment, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, 510300, PR China; Key Laboratory of Efficient Utilization and Processing of Marine Fishery Resources of Hainan Province, Sanya Tropical Fisheries Research Institute, Sanya, 572018, PR China.
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4
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Dichiera AM, De Anda V, Gilmour KM, Baker BJ, Esbaugh AJ. Functional divergence of teleost carbonic anhydrase 4. Comp Biochem Physiol A Mol Integr Physiol 2023; 277:111368. [PMID: 36642322 DOI: 10.1016/j.cbpa.2023.111368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 12/14/2022] [Accepted: 01/10/2023] [Indexed: 01/15/2023]
Abstract
The functional role of membrane-bound carbonic anhydrases (CAs) has been of keen interest in the past decade, and in particular, studies have linked CA in red muscle, heart, and eye to enhanced tissue oxygen extraction in bony fishes (teleosts). However, the number of purported membrane-bound CA isoforms in teleosts, combined with the imperfect system of CA isoform nomenclature, present roadblocks for ascribing physiological functions to particular CA isoforms across different teleost lineages. Here we developed an organizational framework for membrane-bound CAs in teleosts, providing the latest phylogenetic analysis of extant CA4 and CA4-like isoforms. Our data confirm that there are three distinct isoforms of CA4 (a, b, and c) that are conserved across major teleost lineages, with the exception of CA4c gene being lost in salmonids. Tissue distribution analyses suggest CA4a functions in oxygen delivery across teleost lineages, while CA4b may be specialized for renal acid-base balance and ion regulation. This work provides an important foundation for researchers to elucidate the functional significance of CA4 isoforms in fishes.
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Affiliation(s)
- Angelina M Dichiera
- Department of Zoology, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada.
| | - Valerie De Anda
- Marine Science Institute, The University of Texas at Austin, Port Aransas, TX 78373, USA. https://twitter.com/val_deanda
| | | | - Brett J Baker
- Marine Science Institute, The University of Texas at Austin, Port Aransas, TX 78373, USA; Department of Integrative Biology, The University of Texas at Austin, Austin, TX 78712, USA. https://twitter.com/archaeal
| | - Andrew J Esbaugh
- Marine Science Institute, The University of Texas at Austin, Port Aransas, TX 78373, USA
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5
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Sharker MR, Kim SC, Hossen S, Sumi KR, Choi SK, Choi KS, Kho KH. Carbonic Anhydrase in Pacific Abalone Haliotis discus hannai: Characterization, Expression, and Role in Biomineralization. Front Mol Biosci 2021; 8:655115. [PMID: 33937335 PMCID: PMC8082251 DOI: 10.3389/fmolb.2021.655115] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 02/24/2021] [Indexed: 12/18/2022] Open
Abstract
Carbonic anhydrases (CAs) are universal zinc ion containing metalloenzymes that play a pivotal role in various physiological processes. In this study, a CA I (designated as Hdh CA I) was isolated and characterized from the mantle tissue of Pacific abalone, Haliotis discus hannai. The full-length cDNA sequence of Hdh CA I was 1,417-bp in length, encoding a protein of 337 amino acids with molecular weight of 37.58 kDa. Hdh CA I sequence possessed a putative signal peptide of 22 amino acids and a CA catalytic function domain. The predicted protein shared 94 and 78% sequence identities with Haliotis gigantea and Haliotis tuberculata CA I, respectively. Results of phylogenetic analysis indicated that Hdh CA I was evolutionarily close to CA I of H. gigantea and H. tuberculata with high bootstrap values. Significantly higher levels of Hdh CA I mRNA transcript were found in mantle than other examined tissues. In situ hybridization results showed strong hybridization signals in epithelial cells of the dorsal mantle pallial, an area known to synthesize and secrete proteins responsible for the nacreous layer formation of shell. This is the first study on Hdh CA I in H. discus hannai and the results may contribute to further study its physiological functions in shell biomineralization of abalone.
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Affiliation(s)
- Md. Rajib Sharker
- Department of Fisheries Science, College of Fisheries and Ocean Sciences, Chonnam National University, Yeosu, South Korea
- Department of Fisheries Biology and Genetics, Faculty of Fisheries, Patuakhali Science and Technology University, Patuakhali, Bangladesh
| | - Soo Cheol Kim
- Department of Fisheries Science, College of Fisheries and Ocean Sciences, Chonnam National University, Yeosu, South Korea
| | - Shaharior Hossen
- Department of Fisheries Science, College of Fisheries and Ocean Sciences, Chonnam National University, Yeosu, South Korea
| | - Kanij Rukshana Sumi
- Department of Aquaculture, Faculty of Fisheries, Patuakhali Science and Technology University, Patuakhali, Bangladesh
| | - Sang Ki Choi
- Department of Biological Sciences, College of Life Industry and Science, Sunchon National University, Suncheon, South Korea
| | - Kap Seong Choi
- Department of Food Science and Technology, Sunchon National University, Suncheon, South Korea
| | - Kang Hee Kho
- Department of Fisheries Science, College of Fisheries and Ocean Sciences, Chonnam National University, Yeosu, South Korea
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6
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Zimmer AM, Mandic M, Yew HM, Kunert E, Pan YK, Ha J, Kwong RWM, Gilmour KM, Perry SF. Use of a carbonic anhydrase Ca17a knockout to investigate mechanisms of ion uptake in zebrafish ( Danio rerio). Am J Physiol Regul Integr Comp Physiol 2021; 320:R55-R68. [PMID: 33085911 DOI: 10.1152/ajpregu.00215.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In fishes, branchial cytosolic carbonic anhydrase (CA) plays an important role in ion and acid-base regulation. The Ca17a isoform in zebrafish (Danio rerio) is expressed abundantly in Na+-absorbing/H+-secreting H+-ATPase-rich (HR) cells. The present study aimed to identify the role of Ca17a in ion and acid-base regulation across life stages using CRISPR/Cas9 gene editing. However, in preliminary experiments, we established that ca17a knockout is lethal with ca17a-/- mutants exhibiting a significant decrease in survival beginning at ∼12 days postfertilization (dpf) and with no individuals surviving past 19 dpf. Based on these findings, we hypothesized that ca17a-/- mutants would display alterations in ion and acid-base balance and that these physiological disturbances might underlie their early demise. Na+ uptake rates were significantly increased by up to 300% in homozygous mutants compared with wild-type individuals at 4 and 9 dpf; however, whole body Na+ content remained constant. While Cl- uptake was significantly reduced in ca17a-/- mutants, Cl- content was unaffected. Reduction of CA activity by Ca17a morpholino knockdown or ethoxzolamide treatments similarly reduced Cl- uptake, implicating Ca17a in the mechanism of Cl- uptake by larval zebrafish. H+ secretion, O2 consumption, CO2 excretion, and ammonia excretion were generally unaltered in ca17a-/- mutants. In conclusion, while the loss of Ca17a caused marked changes in ion uptake rates, providing strong evidence for a Ca17a-dependent Cl- uptake mechanism, the underlying causes of the lethality of this mutation in zebrafish remain unclear.
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Affiliation(s)
- Alex M Zimmer
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
| | - Milica Mandic
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
| | - Hong Meng Yew
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
| | - Emma Kunert
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
| | - Yihang K Pan
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
| | - Jimmy Ha
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
| | - Raymond W M Kwong
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
| | | | - Steve F Perry
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
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7
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Yao Z, Schauer KL, Ruhr IM, Mager EM, Heuer RM, Grosell M. A marine teleost, Opsanus beta, compensates acidosis in hypersaline water by H + excretion or reduced HCO 3- excretion rather than HCO 3- uptake. J Comp Physiol B 2020; 191:85-98. [PMID: 33070210 DOI: 10.1007/s00360-020-01320-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 09/10/2020] [Accepted: 09/29/2020] [Indexed: 10/23/2022]
Abstract
Increases in ambient salinity demand parallel increases in intestinal base secretion for maintenance of osmoregulatory status, which is likely the cause of a transient acidosis following transfer of euryhaline fish from freshwater to seawater. It was predicted that transfer of the marine Gulf toadfish (Opsanus beta) from seawater (35 ppt) to hypersaline (60 ppt) seawater (HSW) would lead to a transient acidosis that would be compensated by increases in branchial acid excretion to offset the acid-base disturbance. Toadfish exposed to HSW showed a significant decrease in blood pH and [HCO3-] but no increase in pCO2, followed by a full recovery after 48-96 h. A similar metabolic acidosis and recovery was found when fish were exposed to 60-ppt HCO3--free seawater (HEPES-buffered), which may suggest that compensation for intestinal base loss during hypersaline treatment is from gill H+ excretion rather than gill HCO3- uptake. However, we cannot rule out that reduced branchial HCO3- excretion contributed to an increase in net acid excretion. Since colchicine prevents full compensation, translocation of H+ and/or HCO3- transporters between cytosolic compartments and plasma membrane fractions might be involved in compensating for the hypersalinity-induced acidosis. Translocation of transporters rather than de novo synthesis may represent a faster and less energetically demanding response to rapidly fluctuating and high salinities encountered by toadfish in their natural environment.
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Affiliation(s)
- Zongli Yao
- Sino-US joint laboratory of Aquatic Animal Physiology, East China Sea Fisheries Research Institute, Chinese Academy of Fisheries Sciences, Shanghai, China. .,Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, USA.
| | - Kevin L Schauer
- Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, USA
| | - Ilan M Ruhr
- Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, USA.,Cardiovascular Sciences, School of Medical Sciences, The University of Manchester, Manchester, UK
| | - Edward M Mager
- Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, USA.,Department of Biological Sciences, University of North Texas, Denton, TX, USA
| | - Rachael M Heuer
- Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, USA
| | - Martin Grosell
- Sino-US joint laboratory of Aquatic Animal Physiology, East China Sea Fisheries Research Institute, Chinese Academy of Fisheries Sciences, Shanghai, China.,Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, USA
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8
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Shir-Mohammadi K, Perry SF. Expression of ion transport genes in ionocytes isolated from larval zebrafish ( Danio rerio) exposed to acidic or Na +-deficient water. Am J Physiol Regul Integr Comp Physiol 2020; 319:R412-R427. [PMID: 32755465 DOI: 10.1152/ajpregu.00095.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In zebrafish (Danio rerio), a specific ionocyte subtype, the H+-ATPase-rich (HR) cell, is presumed to be a significant site of transepithelial Na+ uptake/acid secretion. During acclimation to environments differing in ionic composition or pH, ionic and acid-base regulations are achieved by adjustments to the activity level of HR cell ion transport proteins. In previous studies, the quantitative assessment of mRNA levels for genes involved in ionic and acid-base regulations relied on measurements using homogenates derived from the whole body (larvae) or the gill (adult). Such studies cannot distinguish whether any differences in gene expression arise from adjustments of ionocyte subtype numbers or transcriptional regulation specifically within individual ionocytes. The goal of the present study was to use fluorescence-activated cell sorting to separate the HR cells from other cellular subpopulations to facilitate the measurement of gene expression of HR cell-specific transporters and enzymes from larvae exposed to low pH (pH 4.0) or low Na+ (5 μM) conditions. The data demonstrate that treatment of larvae with acidic water for 4 days postfertilization caused cell-specific increases in H+-ATPase (atp6v1aa), ca17a, ca15a, nhe3b, and rhcgb mRNA in addition to increases in mRNA linked to cell proliferation. In fish exposed to low Na+, expression of nhe3b and rhcgb was increased owing to HR cell-specific regulation and elevated numbers of HR cells. Thus, the results of this study demonstrate that acclimation to low pH or low Na+ environmental conditions is facilitated by HR cell-specific transcriptional control and by HR cell proliferation.
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Affiliation(s)
| | - S F Perry
- Department of Biology, University of Ottawa, Ontario, Canada
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9
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Lonthair J, Dichiera AM, Esbaugh AJ. Mechanisms of acid-base regulation following respiratory alkalosis in red drum (Sciaenops ocellatus). Comp Biochem Physiol A Mol Integr Physiol 2020; 250:110779. [PMID: 32763467 DOI: 10.1016/j.cbpa.2020.110779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 07/29/2020] [Accepted: 07/29/2020] [Indexed: 10/23/2022]
Abstract
Respiratory acidosis and subsequent metabolic compensation are well-studied processes in fish exposed to elevated CO2 (hypercapnia). Yet, such exposures in the marine environment are invariably accompanied by a return of environmental CO2 to atmospheric baselines. This understudied phenomenon has the potential to cause a respiratory alkalosis that would necessitate base excretion. Here we sought to explore this question and the associated physiological mechanisms that may accompany base excretions using the red drum (Sciaenops ocellatus). As expected, when high pCO2 (15,000 μatm CO2) acclimated red drum were transferred to normal pCO2, their net H+ excretion shifted from positive (0.157 ± 0.044 μmol g-1 h-1) to negative (-0.606 ± 0.116 μmol g-1 h-1) in the 2 h post-transfer period. Net H+ excretion returned to control rates during the 3 to 24 h flux period. Gene expression and enzyme activity assays demonstrated that while the acidosis resulted in significant changes in several relevant transporters, no significant changes accompanied the alkalosis phase. Confocal microscopy was used to assess alkalosis-stimulated translocation of V-type H+ ATPase to the basolateral membrane previously seen in other marine species; however, no apparent translocation was observed. Overall, these data demonstrate that fluctuations in environmental CO2 result in both acidic and alkalotic respiratory disturbances; however, red drum maintain sufficient regulatory capacity to accommodate base excretion. Furthermore, this work does not support a role for basolateral VHA translocation in metabolic compensation from a systemic alkalosis in teleosts.
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Affiliation(s)
- Joshua Lonthair
- Marine Science Institute, University of Texas at Austin, Port Aransas, TX 78373, USA; Department of Environmental Conservation, University of Massachusetts Amherst, Amherst, MA 01003, USA; Fisheries Resources Division, Southwest Fisheries Science Center, National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), La Jolla, CA 92037, USA.
| | - Angelina M Dichiera
- Marine Science Institute, University of Texas at Austin, Port Aransas, TX 78373, USA
| | - Andrew J Esbaugh
- Marine Science Institute, University of Texas at Austin, Port Aransas, TX 78373, USA
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10
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Yew HM, Zimmer AM, Perry SF. Assessing intracellular pH regulation in H +-ATPase-rich ionocytes in zebrafish larvae using in vivo ratiometric imaging. J Exp Biol 2020; 223:jeb212928. [PMID: 32029462 DOI: 10.1242/jeb.212928] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 01/28/2020] [Indexed: 12/11/2022]
Abstract
The H+-ATPase-rich (HR) cells of zebrafish larvae are a sub-type of ion-transporting cell located on the yolk sac epithelium that are responsible for Na+ uptake and H+ extrusion. Current models of HR cell ion transport mechanisms in zebrafish larvae are well established, but little is known about the involvement of the various ion transport pathways in regulating intracellular acid-base status. Here, a ratiometric imaging technique was developed and validated to monitor intracellular pH (pHi) continuously in larval zebrafish HR cells in vivo Gene knockdown or CRISPR/Cas9 knockout approaches were used to evaluate the roles of the two principal apical membrane acid excretory pathways, the Na+/H+ exchanger (NHE3b; slc9a3.2) and the H+-ATPase (atpv1aa). Additionally, the role of HR cell cytosolic carbonic anhydrase (CAc) was investigated because of its presumed role in providing H+ for Na+/H+ exchange and H+-ATPase. The temporal pattern and extent of intracellular acidification during exposure of fish to 1% CO2 and the extent of post-CO2 alkalisation were altered markedly in fish experiencing knockdown/knockout of CAc, NHE3b or H+-ATPase. Although there were slight differences among the three knockdown/knockout experiments, the typical response was a greater degree of intracellular acidification during CO2 exposure and a reduced capacity to restore pHi to baseline levels post-hypercapnia. The metabolic alkalosis and subsequent acidification associated with 20 mmol l-1 NH4Cl exposure and its washout were largely unaffected by gene knockdown. Overall, the results suggest markedly different mechanisms of intracellular acid-base regulation in zebrafish HR cells depending on the nature of the acid-base disturbance.
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Affiliation(s)
- H M Yew
- Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, ON KIN 6N5, Canada
| | - A M Zimmer
- Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, ON KIN 6N5, Canada
| | - S F Perry
- Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, ON KIN 6N5, Canada
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11
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Chen Y, Bai Y, Hu X, Yang X, Xu S. Energy metabolism responses in muscle tissue of rainbow trout Oncorhynchus mykiss fry to CO 2-induced aquatic acidification based on metabolomics. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2020; 220:105400. [PMID: 31901577 DOI: 10.1016/j.aquatox.2019.105400] [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: 10/09/2019] [Revised: 12/23/2019] [Accepted: 12/27/2019] [Indexed: 06/10/2023]
Abstract
We investigated the impacts of carbon dioxide (CO2)-induced acidification on energy metabolism in muscle tissue of rainbow trout Oncorhynchus mykiss fry. Fry were exposed to freshwater in equilibrium with air containing CO2 at volume concentrations of 380, 1000 and 2000 ppm for 30 days. At this critical and sensitive life stage, we showed dose-dependent reductions in weight gain and changes in energy metabolism under projected future CO2 levels. Rainbow trout fry exposed to elevated CO2 concentrations produced more energy in muscle tissue because ATP levels were significantly elevated. Fry exposed to 1000 ppm CO2 had a higher activity of pyruvate kinase (PK), higher concentrations of pyruvate, acetate, 2-oxoglutarate, phenylalanine, tyrosine, inosine, uracil and uridine, and lower concentrations of anserine and IMP in muscle tissue based on metabolomic analysis. We infer that the increased ATP production in fry exposed to 1000 ppm CO2 is produced through glycolysis. In the 2000 ppm group, the protein content of muscle was lower than in the control, and the activities of PK, cytochrome C oxidase (COX), Na+/K+-ATP and Ca2+/Mg2+-ATPase were significantly higher. Concentrations of pyruvate, 2-oxoglutarate, histidine, anserine and IMP were significantly lower, and alanine, methionine, leucine, isoleucine, valine, lysine, pantothenate, uracil and inosine were significantly higher. Accelerated tissue decomposition may have sustained the higher production of ATP in the 2000 ppm group.
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Affiliation(s)
- Yan Chen
- National Engineering Research Center for Freshwaters, Beijing Fisheries Research Institute, Fishery Biology Technology Key Laboratory of Beijing, Beijing 100068, PR China
| | - Yucen Bai
- China Rural Technology Development Center, 54 Sanlihe Road, Beijing, 100045, PR China.
| | - Xiaolu Hu
- China Rural Technology Development Center, 54 Sanlihe Road, Beijing, 100045, PR China
| | - Xiaofei Yang
- National Engineering Research Center for Freshwaters, Beijing Fisheries Research Institute, Fishery Biology Technology Key Laboratory of Beijing, Beijing 100068, PR China
| | - Shaogang Xu
- National Engineering Research Center for Freshwaters, Beijing Fisheries Research Institute, Fishery Biology Technology Key Laboratory of Beijing, Beijing 100068, PR China.
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12
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McMillan OJL, Dichiera AM, Harter TS, Wilson JM, Esbaugh AJ, Brauner CJ. Blood and Gill Carbonic Anhydrase in the Context of a Chondrichthyan Model of CO 2 Excretion. Physiol Biochem Zool 2020; 92:554-566. [PMID: 31567050 DOI: 10.1086/705402] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Pacific spiny dogfish (Squalus suckleyi) have been widely used as a representative species for chondrichthyan CO2 excretion. Pacific spiny dogfish have a slower red blood cell (RBC) carbonic anhydrase (CA) isoform than teleost fishes, extracellular CA activity, no endogenous plasma CA inhibitor, and plasma-accessible CA IV at the gills. Thus, both the RBC and plasma compartments contribute to bicarbonate ion (HCO3-) dehydration at the gills for CO2 excretion in contrast to teleost fishes, in which HCO3- dehydration is restricted to RBCs. We compared CA activity levels, subcellular localization, and presence of plasma CA inhibitors in the blood and gills of 13 chondrichthyans to examine the hypothesis that the dogfish model of CO2 excretion applies broadly to chondrichthyans. In general, blood samples from the 12 other chondrichthyans examined had lower RBC CA activity than teleosts, some extracellular CA activity, and no endogenous plasma CA inhibitor. While type IV-like membrane-associated CA was found in the gills in all four of the chondrichthyans examined, S. suckleyi had three times more CA activity (183±13.2 μmol CO2 min-1 mg protein-1) in the microsomal (membrane) fraction of gills than the other three. In addition, unexpected variation in CA characteristics was observed between chondrichthyan species. Thus, in general, it appears that the pattern of CA distribution in fishes can be generally categorized as either chondrichthyan or teleost models. However, further studies should examine the functional significance of the within-chondrichthyan differences we observed and investigate whether CO2 excretion patterns exist along a continuum or in discrete groups.
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13
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Fehsenfeld S, Kolosov D, Wood CM, O'Donnell MJ. Section-specific H + flux in renal tubules of fasted and fed goldfish. ACTA ACUST UNITED AC 2019; 222:jeb.200964. [PMID: 31138633 DOI: 10.1242/jeb.200964] [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: 01/31/2019] [Accepted: 05/21/2019] [Indexed: 12/12/2022]
Abstract
A recent study demonstrated that in response to a feeding-induced metabolic acidosis, goldfish (Carassius auratus) adjust epithelial protein and/or mRNA expression in their kidney tubules for multiple transporters known to be relevant for acid-base regulation. These include Na+/H+ exchanger (NHE), V-type H+-ATPase (V-ATPase), cytoplasmic carbonic anhydrase, HCO3 - transporters and Rhesus proteins. Consequently, renal acid output in the form of protons and NH4 + increases. However, little is known about the mechanistic details of renal acid-base regulation in C. auratus and teleost fishes in general. The present study applied the scanning ion-selective electrode technique (SIET) to measure proton flux in proximal, distal and connecting tubules of goldfish. We detected increased H+ efflux into the extracellular fluid from the tubule in fed animals, resulting from paracellular back-flux of H+ through the tight junction. By applying inhibitors for selected acid-base regulatory epithelial transporters, we found that cytosolic carbonic anhydrase and HCO3 - transporters were important in mediating H+ flux in all three tubule segments of fed goldfish. Contrastingly, V-ATPase seemed to play a role in H+ flux only in proximal and distal tubules, and NHE in proximal and connecting tubules. We developed working models for transport of acid-base relevant equivalents (H+, HCO3 -, NH3/NH4 +) for each tubule segment in C. auratus kidney. While the proximal tubule appears to play a major role in both H+ secretion and HCO3 - reabsorption, the distal and connecting tubules seem to mainly serve for HCO3 - reabsorption and NH3/NH4 + secretion.
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Affiliation(s)
- Sandra Fehsenfeld
- Département de Biologie, Chimie et Géographie, Université du Québec à Rimouski, Rimouski, QC, G5L 3A1, Canada .,Department of Zoology, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Dennis Kolosov
- Department of Biology, McMaster University, Hamilton, ON, L8S 4K1, Canada
| | - Chris M Wood
- Department of Zoology, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.,Department of Biology, McMaster University, Hamilton, ON, L8S 4K1, Canada
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14
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Ion uptake pathways in European sea bass Dicentrarchus labrax. Gene 2019; 692:126-137. [DOI: 10.1016/j.gene.2019.01.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 12/12/2018] [Accepted: 01/02/2019] [Indexed: 01/20/2023]
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15
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Brauner CJ, Shartau RB, Damsgaard C, Esbaugh AJ, Wilson RW, Grosell M. Acid-base physiology and CO2 homeostasis: Regulation and compensation in response to elevated environmental CO2. FISH PHYSIOLOGY 2019. [DOI: 10.1016/bs.fp.2019.08.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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16
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Sumi KR, Kim SC, Natarajan S, Choi KS, Choi MR, Kim HT, Park JI, Nou IS, Gilmour KM, Kho KH. Molecular cloning and characterization of secretory carbonic anhydrase VI in pufferfish (Takifugu rubripes). Gene 2018; 640:57-65. [PMID: 29030255 DOI: 10.1016/j.gene.2017.10.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 10/05/2017] [Indexed: 11/29/2022]
Abstract
Carbonic anhydrase VI (CA VI) has been characterized as a secretory isozyme in mammals. Our present study confirmed the occurrence of CA VI in pufferfish (Takifugu rubripes). In this study, genomic sequence information for the CA VI of pufferfish was used for molecular cloning. We cloned a 1821 bp cDNA sequence, which consisted of a complete coding sequence of 1623bp and a deduced amino acid sequence of 540 amino acids from the open reading frame. A BLAST search indicated that this protein exhibits 53%, 79%, and 67% identity with human, tilapia, and gar CA VI, respectively. It also shows 63%-77% identity with other fish CA VI-like sequences (zebrafish, Asian arowana, salmon, and large yellow croaker). Moreover, alignment of two or more sequences revealed that the protein sequence of pufferfish CA VI has 34%-37% identity with mammalian and fish CA II sequences. An NH2-terminal signal peptide of 18 amino acids in length was predicted in the pufferfish CA VI sequence. Three potential N-linked glycosylation sites and two cysteine residues (Cys-28 and Cys-209) that are likely to form one disulfide bond were present in pufferfish CA VI. In silico and phylogenetic analyses revealed that pufferfish CA VI is an extracellular secretory protein. Active site analysis indicated that this protein is a low-activity CA isozymes due to a characteristic Val/Ile substitution at position 207. Homology modeling of puffer CA VI was performed using the crystal structure of human carbonic anhydrase XIV as a template structure, based on high similarity. Reverse transcription-polymerase chain reaction (PCR), quantitative PCR and in situ hybridization results revealed that, the pufferfish CA VI is highly expressed in liver tissue.
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Affiliation(s)
- Kanij Rukshana Sumi
- Department of Fisheries Science, College of Fisheries and Ocean Sciences, Chonnam National University, 50, Daehak-ro, Yeosu, Jeonnam 59626, Republic of Korea.
| | - Soo Cheol Kim
- Department of Biomedical and Electronic Engineering, College of Engineering, Chonnam National University, Yeosu 59626, Republic of Korea
| | - Sathishkumar Natarajan
- Department of Horticulture, College of Life Science and Natural Resources, Sunchon National University, 255, Jungang-ro, Suncheon-Si, Jeollanam-do 57922, Republic of Korea
| | - Kap Seong Choi
- Department of Food Science and Technology, College of Life Science and Natural Resources, Sunchon National University, 255, Jungang-ro, Suncheon-Si, Jeollanam-do 57922, Republic of Korea.
| | - Myeong Rak Choi
- Department of Biomedical and Electronic Engineering, College of Engineering, Chonnam National University, Yeosu 59626, Republic of Korea.
| | - Hoy-Taek Kim
- Department of Horticulture, College of Life Science and Natural Resources, Sunchon National University, 255, Jungang-ro, Suncheon-Si, Jeollanam-do 57922, Republic of Korea.
| | - Jong-In Park
- Department of Horticulture, College of Life Science and Natural Resources, Sunchon National University, 255, Jungang-ro, Suncheon-Si, Jeollanam-do 57922, Republic of Korea.
| | - Ill-Sup Nou
- Department of Horticulture, College of Life Science and Natural Resources, Sunchon National University, 255, Jungang-ro, Suncheon-Si, Jeollanam-do 57922, Republic of Korea.
| | - Kathleen M Gilmour
- Department of Biology, Centre for Advanced Research in Environmental Genomics, University of Ottawa, Ottawa, Ontario, Canada.
| | - Kang Hee Kho
- Department of Fisheries Science, College of Fisheries and Ocean Sciences, Chonnam National University, 50, Daehak-ro, Yeosu, Jeonnam 59626, Republic of Korea.
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17
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Brannen M, Gilmour KM. Carbonic anhydrase expression in the branchial ionocytes of rainbow trout. J Exp Biol 2018; 221:jeb.164582. [DOI: 10.1242/jeb.164582] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 01/22/2018] [Indexed: 12/13/2022]
Abstract
Rainbow trout (Oncorhynchus mykiss) exposed to acid-base challenges activate branchial mechanisms for the excretion of acid-base equivalents. Current models of branchial acid-base excretion in freshwater rainbow trout propose two main ionocyte types; the peanut lectin agglutinin-positive (PNA+) mitochondrion-rich cell or ionocyte is believed to secrete HCO3− in exchange for Cl−, whereas H+ secretion is thought to occur across PNA− ionocytes in exchange for Na+. Both HCO3− and H+ are supplied by intracellular hydration of CO2 catalyzed by cytosolic carbonic anhydrase (CAc). Immunohistochemical approaches revealed that under control conditions, CAc was detectable in 92.3±1.0% (N=11) of PNA− ionocytes, and the abundance of PNA− ionocytes increased in response to systemic acidosis elicited by 72 h exposure to water of low pH (nominally pH 4.5), hypercapnia (1% CO2, nominally 7.6 Torr) or hyperoxia (achieved by gassing water with pure O2), as did the abundance of PNA− ionocytes that exhibited immunofluorescence for CAc. However, just 4.3 ± 0.6% (N=11) of PNA+ ionocytes expressed detectable CAc under control conditions. Marked increases in the abundance of CAc-positive PNA+ ionocytes were detected following exposure of trout to a base load via recovery from hypercapnia, or base infusion (72 h infusion with 140 mmol L−1 NaHCO3). The percentage of CAc-positive PNA+ ionocytes also was increased in trout treated with cortisol (10 mg kg−1 hydrocortisone 21-hemisuccinate daily for 7 d). These results suggest that regulation of CA within PNA+ ionocytes and/or the abundance of CAc-positive PNA+ ionocytes plays a role in activating base secretion in response to systemic alkalosis.
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Affiliation(s)
- Michael Brannen
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
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18
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Sulukan E, Köktürk M, Ceylan H, Beydemir Ş, Işik M, Atamanalp M, Ceyhun SB. An approach to clarify the effect mechanism of glyphosate on body malformations during embryonic development of zebrafish (Daino rerio). CHEMOSPHERE 2017; 180:77-85. [PMID: 28391155 DOI: 10.1016/j.chemosphere.2017.04.018] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 04/01/2017] [Accepted: 04/03/2017] [Indexed: 06/07/2023]
Abstract
In this study, it has been investigated that the effects of glyphosate, which is a herbicide within organophosphate and unselective widely used in agriculture on enzyme activity of carbonic anhydrase, production of reactive oxygen species, cell apoptosis and body morphology during the embryonic development of zebrafish. To this end, it has been treated embryo with 1, 5, 10 and 100 mg/L gyphosate at 96 h. The embryos treated with glyphosate from 4 hpf were evaluated by considering the survival rates, hatching rates, body malformations under the stereo microscope in 24, 48, 72 and 96th hours. In order to clarify the mechanism of the abnormalities ROS, enzyme activity of carbonic anhydrase and cellular death were detected end of the 96th hour. The data obtained in the present study have shown that glyphosate treatment inhibited CA activity, caused production of ROS especially branchial regions, triggered cellular apoptosis and caused several types of malformations including pericardial edema, yolk sac edema, spinal curvature and body malformation in a dose-dependent manner. As a conclusion, in light of present and previous studies, we can deduce that (1) the probable reason of ROS production was CA inhibition via decreasing of CO2 extraction and developing respiratory acidosis (however, one needs to clarify), (2) abundance of ROS triggered cellular apoptosis and (3) as a result of cellular apoptosis malformations increased. These data will enable us to further understand potential toxic mechanism of glyphosate on embryonic development stage of zebrafish and may be useful for assessment in the toxicology studies.
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Affiliation(s)
- Ekrem Sulukan
- Atatürk University, Fisheries Faculty, Aquaculture Department, Erzurum, Turkey
| | - Mine Köktürk
- Atatürk University, Fisheries Faculty, Aquaculture Department, Erzurum, Turkey; Atatürk University, Fisheries Faculty, Aquatic Biotechnology Laboratory, Erzurum, Turkey
| | - Hamid Ceylan
- Atatürk University, Science Faculty, Molecular Biology and Genetic Department, Erzurum, Turkey
| | - Şükrü Beydemir
- Anadolu University, Faculty of Pharmacy, Department of Biochemistry, Eskişehir, Turkey
| | - Mesut Işik
- Harran University, Department of Medical Services and Techniques, Health Services Vocational School, Şanlıurfa, Turkey
| | - Muhammed Atamanalp
- Atatürk University, Fisheries Faculty, Aquaculture Department, Erzurum, Turkey
| | - Saltuk Buğrahan Ceyhun
- Atatürk University, Fisheries Faculty, Aquaculture Department, Erzurum, Turkey; Atatürk University, Fisheries Faculty, Aquatic Biotechnology Laboratory, Erzurum, Turkey.
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19
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Allmon EB, Esbaugh AJ. Carbon dioxide induced plasticity of branchial acid-base pathways in an estuarine teleost. Sci Rep 2017; 7:45680. [PMID: 28378831 PMCID: PMC5381225 DOI: 10.1038/srep45680] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 03/02/2017] [Indexed: 12/21/2022] Open
Abstract
Anthropogenic CO2 is expected to drive ocean pCO2 above 1,000 μatm by 2100 – inducing respiratory acidosis in fish that must be corrected through branchial ion transport. This study examined the time course and plasticity of branchial metabolic compensation in response to varying levels of CO2 in an estuarine fish, the red drum, which regularly encounters elevated CO2 and may therefore have intrinsic resilience. Under control conditions fish exhibited net base excretion; however, CO2 exposure resulted in a dose dependent increase in acid excretion during the initial 2 h. This returned to baseline levels during the second 2 h interval for exposures up to 5,000 μatm, but remained elevated for exposures above 15,000 μatm. Plasticity was assessed via gene expression in three CO2 treatments: environmentally realistic 1,000 and 6,000 μatm exposures, and a proof-of-principle 30,000 μatm exposure. Few differences were observed at 1,000 or 6,000 μatm; however, 30,000 μatm stimulated widespread up-regulation. Translocation of V-type ATPase after 1 h of exposure to 30,000 μatm was also assessed; however, no evidence of translocation was found. These results indicate that red drum can quickly compensate to environmentally relevant acid-base disturbances using baseline cellular machinery, yet are capable of plasticity in response to extreme acid-base challenges.
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Affiliation(s)
- Elizabeth B Allmon
- University of Texas at Austin, University of Texas Marine Science Institute, Port Aransas, TX 78373, USA
| | - Andrew J Esbaugh
- University of Texas at Austin, University of Texas Marine Science Institute, Port Aransas, TX 78373, USA
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20
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Synergistic Effects of Micro-electrolysis-Photocatalysis on Water Treatment and Fish Performance in Saline Recirculating Aquaculture System. Sci Rep 2017; 7:45066. [PMID: 28345583 PMCID: PMC5366865 DOI: 10.1038/srep45066] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 02/17/2017] [Indexed: 01/30/2023] Open
Abstract
A new physico-chemical process for TAN (total ammonia nitrogen) removal and disinfection is introduced in saline recirculating aquaculture system (RAS), in which the biofilter is replaced with an integrated electrolysis cell and an activated carbon filter. The electrolysis cell which is based on micro current electrolysis combined with UV-light was self-designed. After the fundamental research, a small pilot scale RAS was operated for 30 days to verify the technical feasibility. The system was stocked by 42 GIFT tilapia (Oreochromis niloticus) fish with the rearing density of 13 kg/m3. During the experiments, the TAN concentration remained below 1.0 mg/L. The nitrite concentration was lower than 0.2 mg/L and the nitrate concentration had increased continuously to 12.79 mg/L at the end. Furthermore, the concentration of residual chlorine in culture ponds remained below 0.3 mg/L, ORP maintained slight fluctuations in the range of 190~240 mV, and pH of the water showed the downtrend. Tilapia weight increased constantly to 339.3 ± 10 g. For disinfection, the active chlorine generated by electrochemical treatment caused Escherichia coli inactivation. Enzyme activity assay indicated that the activity of glutamate dehydrogenase, carbonic anhydrase and glutamic pyruvic transaminase increased within the normal range. The preliminary feasibility was verified by using this physico-chemical technology in the RAS.
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21
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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: 91] [Impact Index Per Article: 13.0] [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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22
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Harter TS, Brauner CJ. The O 2 and CO 2 Transport System in Teleosts and the Specialized Mechanisms That Enhance Hb–O 2 Unloading to Tissues. ACTA ACUST UNITED AC 2017. [DOI: 10.1016/bs.fp.2017.09.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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23
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Carrie D, Gilmour KM. Phosphorylation increases the catalytic activity of rainbow trout gill cytosolic carbonic anhydrase. J Comp Physiol B 2016; 186:111-22. [PMID: 26498599 DOI: 10.1007/s00360-015-0942-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Revised: 09/30/2015] [Accepted: 10/11/2015] [Indexed: 11/26/2022]
Abstract
Cytoplasmic carbonic anhydrase (CAc) in the gill of teleost fish contributes to ionic regulation and acid–base balance by catalyzing the reversible reaction of CO2 and water, CO2 + H2O ↔ H(+) + HCO3(-). Regulation of CAc abundance and activity therefore is expected to fine-tune responses to ionic or acid–base challenges. The present study investigated the potential for gill CAc of rainbow trout, Oncorhynchus mykiss (tCAc), to undergo reversible phosphorylation. The activity of tCAc was approximately doubled by phosphorylation achieved through in vitro stimulation of endogenous protein kinases; kinase stimulation doubled phospho-threonine content from that observed in tCAc isolated under conditions where both kinases and protein phosphatases were inhibited. In vitro incubation to preferentially stimulate specific kinases implicated protein kinase G (PKG) in mediating the increase in tCAc activity. The kinetic parameters of turnover number (k cat) and substrate affinity (K m) were similarly affected by stimulation of either kinase or phosphatase action. However, phosphorylation via kinase stimulation significantly increased the efficiency of tCAc (V max /K m), and this factor may have contributed to the elevation of tCAc activity. In addition, phosphorylation of tCAc by kinase stimulation significantly increased the inhibition constant (K i) for acetazolamide. These results demonstrate that tCAc is subject to reversible phosphorylation; future work should focus on identifying the physiological situation(s) in which phosphorylation of trout branchial CAc occurs.
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24
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Ferreira-Martins D, McCormick SD, Campos A, Lopes-Marques M, Osório H, Coimbra J, Castro LFC, Wilson JM. A cytosolic carbonic anhydrase molecular switch occurs in the gills of metamorphic sea lamprey. Sci Rep 2016; 6:33954. [PMID: 27703170 PMCID: PMC5050428 DOI: 10.1038/srep33954] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 09/05/2016] [Indexed: 01/12/2023] Open
Abstract
Carbonic anhydrase plays a key role in CO2 transport, acid-base and ion regulation and metabolic processes in vertebrates. While several carbonic anhydrase isoforms have been identified in numerous vertebrate species, basal lineages such as the cyclostomes have remained largely unexamined. Here we investigate the repertoire of cytoplasmic carbonic anhydrases in the sea lamprey (Petromyzon marinus), that has a complex life history marked by a dramatic metamorphosis from a benthic filter-feeding ammocoete larvae into a parasitic juvenile which migrates from freshwater to seawater. We have identified a novel carbonic anhydrase gene (ca19) beyond the single carbonic anhydrase gene (ca18) that was known previously. Phylogenetic analysis and synteny studies suggest that both carbonic anhydrase genes form one or two independent gene lineages and are most likely duplicates retained uniquely in cyclostomes. Quantitative PCR of ca19 and ca18 and protein expression in gill across metamorphosis show that the ca19 levels are highest in ammocoetes and decrease during metamorphosis while ca18 shows the opposite pattern with the highest levels in post-metamorphic juveniles. We propose that a unique molecular switch occurs during lamprey metamorphosis resulting in distinct gill carbonic anhydrases reflecting the contrasting life modes and habitats of these life-history stages.
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Affiliation(s)
- D. Ferreira-Martins
- Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR/CIMAR) Universidade do Porto, 4050-123, Porto, Portugal
- Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, 4050-313, Porto, Portugal
| | - S. D. McCormick
- USGS, Leetown Science Center, S.O. Conte Anadromous Fish Research Laboratory, 01376, Turner Falls MA USA
| | - A. Campos
- Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR/CIMAR) Universidade do Porto, 4050-123, Porto, Portugal
| | - M. Lopes-Marques
- Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR/CIMAR) Universidade do Porto, 4050-123, Porto, Portugal
- Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, 4050-313, Porto, Portugal
| | - H. Osório
- i3s-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135, Porto Portugal
- Instituto de Patologia e Imunologia Molecular da Universidade do Porto, 4200-135, Porto, Portugal
- Departamento de Patologia e Oncologia, Faculdade de Medicina, Universidade do Porto, 4200-319, Porto, Portugal
| | - J. Coimbra
- Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR/CIMAR) Universidade do Porto, 4050-123, Porto, Portugal
| | - L. F. C. Castro
- Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR/CIMAR) Universidade do Porto, 4050-123, Porto, Portugal
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, 4169–007, Porto, Portugal
| | - J. M. Wilson
- Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR/CIMAR) Universidade do Porto, 4050-123, Porto, Portugal
- Department of Biology, Wilfrid Laurier University, N2L 3C5, Waterloo, Canada
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Sumi KR, Nou IS, Kho KH. Identification and expression of a novel carbonic anhydrase isozyme in the pufferfish Takifugu vermicularis. Gene 2016; 588:173-9. [PMID: 27188255 DOI: 10.1016/j.gene.2016.05.024] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 05/10/2016] [Accepted: 05/13/2016] [Indexed: 01/08/2023]
Abstract
Carbonic anhydrase (CA) is a key element for maintaining acid base balance in fish. In our present experiment, novel CA isozymes were identified from the pear puffer (Takifugu vermicularis). Based on the high homology of two predicted CA sequences of the tiger puffer (Takifugu rubripes), a 1715bp novel cDNA was obtained from T. vermicularis. The open reading frame showed a complete coding sequence of 552bp with a deduced peptide sequence of 183 amino acids that exhibited highest (97%) identity with pufferfish putative CA III and CA IV-like sequences. In addition, this translated protein sequence showed 36-37% identity with zebrafish CA IV-like, CA XVa, CA XVb, and CA XVc proteins. Phylogenetic analysis revealed that the pufferfish novel protein (pCAn) was a membrane-bound CA protein. Alignment of multiple CA sequences illustrated that most of the putative active site residues of the pCAn isozyme were situated at highly conserved regions of the CA sequences. Examination of motif distribution suggested that the pCAn isozyme was very similar to the puffer predicted CA IV-like isozyme. Reverse transcription-polymerase chain reaction (PCR) analysis showed highly differential expression in the brain, gills, kidney, and muscle, whereas CA mRNA expression was almost absent in heart, liver, and intestine. Quantitative PCR expression of CA mRNA abundance suggested several-fold higher expression of pCAn isozymes in the gills compared to other tissues tested. Our results suggest that the pCAn isozyme might be related to CA IV-like isozymes. Further functional studies are needed to investigate the function of the pCAn isozyme in T. vermicularis.
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Affiliation(s)
- Kanij Rukshana Sumi
- Department of Fisheries Science, College of Fisheries and Ocean Sciences, Chonnam National University, 50, Daehak-ro, Yeosu, Jeonnam 59626, Republic of Korea.
| | - Ill-Sup Nou
- Department of Horticulture, College of Life Science and Natural Resources, Sunchon National University, 255, Jungang-ro, Suncheon-Si, Jeollanam-do, 67922, Republic of Korea.
| | - Kang Hee Kho
- Department of Fisheries Science, College of Fisheries and Ocean Sciences, Chonnam National University, 50, Daehak-ro, Yeosu, Jeonnam 59626, Republic of Korea.
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The sensing of respiratory gases in fish: Mechanisms and signalling pathways. Respir Physiol Neurobiol 2016; 224:71-9. [DOI: 10.1016/j.resp.2015.06.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 06/16/2015] [Accepted: 06/17/2015] [Indexed: 12/29/2022]
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Yao Z, Lai Q, Hao Z, Chen L, Lin T, Zhou K, Wang H. Carbonic anhydrase 2-like and Na⁺-K⁺-ATPase α gene expression in medaka (Oryzias latipes) under carbonate alkalinity stress. FISH PHYSIOLOGY AND BIOCHEMISTRY 2015; 41:1491-1500. [PMID: 26183260 DOI: 10.1007/s10695-015-0101-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 07/09/2015] [Indexed: 06/04/2023]
Abstract
High carbonate alkalinity is one of the major stress factors for living organisms in saline-alkaline water areas. Acute and chronic effects of carbonate alkalinity on expression of two genes, carbonic anhydrase 2-like (CA2-like) and Na(+)-K(+)-ATPase α subunit (NKA-α) mRNA in medaka (Oryzias latipes) were evaluated to better understand the responses important for coping with a carbonate alkalinity stress. In the acute exposure experiment, the expression of CA2-like and NKA-α mRNA in the gill and kidney of medaka were examined from 0 h to 7 days exposed to 30.4 mM carbonate alkalinity water. Exposure to high carbonate alkalinity resulted in a transitory alkalosis, followed by a transient increase in gill and kidney CA2-like and NKA-α mRNA expression. In the chronic exposure experiment, the expression of these two genes was examined in the gill and kidney at 50 days post-exposure to six different carbonate alkalinity concentrations ranging from 1.5 to 30.4 mM. Gill and kidney CA2-like mRNA levels in 30.4 mM were approximately 10 and 30 times higher than that of the control (1.5 mM), respectively. Less differences were found in NKA-α expression in the 50-days exposure. The results indicate that when transferred to high carbonate alkalinity water, a transitory alkalosis may occur in medaka, followed by compensatory acid-base and ion regulatory responses. Thus, CA2-like and NKA-α are at least two of the important factors that contribute to the regulation of alkalinity stress.
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Affiliation(s)
- Zongli Yao
- Key Laboratory of East China Sea and Oceanic Fishery Resources Exploitation, Ministry of Agriculture of China, East China Sea Fisheries Research Institute, Chinese Academy of Fisheries Sciences, Shanghai, 20090, China.
| | - Qifang Lai
- Key Laboratory of East China Sea and Oceanic Fishery Resources Exploitation, Ministry of Agriculture of China, East China Sea Fisheries Research Institute, Chinese Academy of Fisheries Sciences, Shanghai, 20090, China.
| | - Zhuoran Hao
- Key Laboratory of East China Sea and Oceanic Fishery Resources Exploitation, Ministry of Agriculture of China, East China Sea Fisheries Research Institute, Chinese Academy of Fisheries Sciences, Shanghai, 20090, China.
| | - Ling Chen
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China.
| | - Tingting Lin
- Key Laboratory of East China Sea and Oceanic Fishery Resources Exploitation, Ministry of Agriculture of China, East China Sea Fisheries Research Institute, Chinese Academy of Fisheries Sciences, Shanghai, 20090, China.
| | - Kai Zhou
- Key Laboratory of East China Sea and Oceanic Fishery Resources Exploitation, Ministry of Agriculture of China, East China Sea Fisheries Research Institute, Chinese Academy of Fisheries Sciences, Shanghai, 20090, China.
| | - Hui Wang
- Key Laboratory of East China Sea and Oceanic Fishery Resources Exploitation, Ministry of Agriculture of China, East China Sea Fisheries Research Institute, Chinese Academy of Fisheries Sciences, Shanghai, 20090, China.
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Esbaugh AJ, Ern R, Nordi WM, Johnson AS. Respiratory plasticity is insufficient to alleviate blood acid–base disturbances after acclimation to ocean acidification in the estuarine red drum, Sciaenops ocellatus. J Comp Physiol B 2015; 186:97-109. [DOI: 10.1007/s00360-015-0940-6] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Revised: 09/23/2015] [Accepted: 10/04/2015] [Indexed: 01/10/2023]
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29
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Gymnocypris przewalskii decreases cytosolic carbonic anhydrase expression to compensate for respiratory alkalosis and osmoregulation in the saline-alkaline lake Qinghai. J Comp Physiol B 2015; 186:83-95. [DOI: 10.1007/s00360-015-0939-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Revised: 09/27/2015] [Accepted: 10/04/2015] [Indexed: 12/29/2022]
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30
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Esbaugh AJ, Secor SM, Grosell M. Characterization of carbonic anhydrase XIII in the erythrocytes of the Burmese python, Python molurus bivittatus. Comp Biochem Physiol B Biochem Mol Biol 2015; 187:71-7. [PMID: 26005204 DOI: 10.1016/j.cbpb.2015.05.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 05/08/2015] [Accepted: 05/11/2015] [Indexed: 11/28/2022]
Abstract
Carbonic anhydrase (CA) is one of the most abundant proteins found in vertebrate erythrocytes with the majority of species expressing a low activity CA I and high activity CA II. However, several phylogenetic gaps remain in our understanding of the expansion of cytoplasmic CA in vertebrate erythrocytes. In particular, very little is known about isoforms from reptiles. The current study sought to characterize the erythrocyte isoforms from two squamate species, Python molurus and Nerodia rhombifer, which was combined with information from recent genome projects to address this important phylogenetic gap. Obtained sequences grouped closely with CA XIII in phylogenetic analyses. CA II mRNA transcripts were also found in erythrocytes, but found at less than half the levels of CA XIII. Structural analysis suggested similar biochemical activity as the respective mammalian isoforms, with CA XIII being a low activity isoform. Biochemical characterization verified that the majority of CA activity in the erythrocytes was due to a high activity CA II-like isoform; however, titration with copper supported the presence of two CA pools. The CA II-like pool accounted for 90 % of the total activity. To assess potential disparate roles of these isoforms a feeding stress was used to up-regulate CO2 excretion pathways. Significant up-regulation of CA II and the anion exchanger was observed; CA XIII was strongly down-regulated. While these results do not provide insight into the role of CA XIII in the erythrocytes, they do suggest that the presence of two isoforms is not simply a case of physiological redundancy.
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Affiliation(s)
- A J Esbaugh
- Department of Marine Science, University of Texas at Austin, Marine Science Institute, 750 Channel View Drive, Port Aransas, TX 78418, USA.
| | - S M Secor
- Department of Biological Sciences, University of Alabama, Tuscaloosa, AL 35487-0344, USA
| | - M Grosell
- Division of Marine Biology and Fisheries, University of Miami, Rosenstiel School of Marine and Atmospheric Science, 4600 Rickenbacker Causeway, Miami, FL 33149, USA
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31
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Heuer RM, Grosell M. Physiological impacts of elevated carbon dioxide and ocean acidification on fish. Am J Physiol Regul Integr Comp Physiol 2014; 307:R1061-84. [DOI: 10.1152/ajpregu.00064.2014] [Citation(s) in RCA: 258] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Most fish studied to date efficiently compensate for a hypercapnic acid-base disturbance; however, many recent studies examining the effects of ocean acidification on fish have documented impacts at CO2 levels predicted to occur before the end of this century. Notable impacts on neurosensory and behavioral endpoints, otolith growth, mitochondrial function, and metabolic rate demonstrate an unexpected sensitivity to current-day and near-future CO2 levels. Most explanations for these effects seem to center on increases in Pco2 and HCO3− that occur in the body during pH compensation for acid-base balance; however, few studies have measured these parameters at environmentally relevant CO2 levels or directly related them to reported negative endpoints. This compensatory response is well documented, but noted variation in dynamic regulation of acid-base transport pathways across species, exposure levels, and exposure duration suggests that multiple strategies may be utilized to cope with hypercapnia. Understanding this regulation and changes in ion gradients in extracellular and intracellular compartments during CO2 exposure could provide a basis for predicting sensitivity and explaining interspecies variation. Based on analysis of the existing literature, the present review presents a clear message that ocean acidification may cause significant effects on fish across multiple physiological systems, suggesting that pH compensation does not necessarily confer tolerance as downstream consequences and tradeoffs occur. It remains difficult to assess if acclimation responses during abrupt CO2 exposures will translate to fitness impacts over longer timescales. Nonetheless, identifying mechanisms and processes that may be subject to selective pressure could be one of many important components of assessing adaptive capacity.
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Affiliation(s)
- Rachael M. Heuer
- Rosenstiel School of Marine and Atmospheric Science, University of Miami, Marine Biology and Fisheries, Miami, Florida
| | - Martin Grosell
- Rosenstiel School of Marine and Atmospheric Science, University of Miami, Marine Biology and Fisheries, Miami, Florida
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32
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Le Roy N, Jackson DJ, Marie B, Ramos-Silva P, Marin F. The evolution of metazoan α-carbonic anhydrases and their roles in calcium carbonate biomineralization. Front Zool 2014. [DOI: 10.1186/s12983-014-0075-8] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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33
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Rahim SM, Mazlan AG, Simon KD, Delaunoy JP, Laurent P. Immunocytochemical localization of carbonic anhydrase in the pseudobranch tissue of the rainbow trout Oncorhynchus mykiss. J Zhejiang Univ Sci B 2014; 15:194-200. [PMID: 24510712 DOI: 10.1631/jzus.b1200297] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Pseudobranch function has long interested scientists, but its role has yet to be elucidated. Several studies have suggested that pseudobranchs serve respiratory, osmoregulatory, and sensory functions. This work investigated the immunolocalization of pseudobranch carbonic anhydrase (CA) in the teleost fish species rainbow trout (Oncorhynchus mykiss) to clarify its physiological function. CA was purified from rainbow trout gills O. mykiss and specific antibodies were raised. Immunoblotting between tissue homogenates of pseudobranch and gill CA antibodies showed specific immunostaining with only one band corresponding to CA in the pseudobranch homogenate. Results of immunohistochemical technique revealed that CA was distributed within pseudobranch cells and more precisely in the apical parts (anti-vascular) of cells. The basal (vascular) parts of cells, tubular system, blood capillaries, and pillar cells were not immunostained. Immunocytochemistry confirmed these results and showed that some CA enzyme was cytoplasmic and the remainder was linked to membranous structures. The results also showed that the lacunar tissue layers did not display immunoperoxidase activity. Our results indicated that pseudobranch CA may have a function related to the extracellular medium wherein CA intervenes with the mechanism of stimulation of afferent nerve fibers.
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Affiliation(s)
- S M Rahim
- Department of Biology, Faculty of Education, University of Tikrit, 34001 Tikrit, Salah Al Deen, Iraq; School of Environmental and Natural Resource Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor Darul Ehsan, Malaysia; Marine Ecosystem Research Centre, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor Darul Ehsan, Malaysia; Laboratoire de Diagnostic Génétique, Faculté de Médcine et CHRU, 67085 Strasbourg, France; Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada
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Santovito G, Marino SM, Sattin G, Cappellini R, Bubacco L, Beltramini M. Cloning and characterization of cytoplasmic carbonic anhydrase from gills of four Antarctic fish: insights into the evolution of fish carbonic anhydrase and cold adaptation. Polar Biol 2012. [DOI: 10.1007/s00300-012-1200-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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35
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Esbaugh AJ, Heuer R, Grosell M. Impacts of ocean acidification on respiratory gas exchange and acid-base balance in a marine teleost, Opsanus beta. J Comp Physiol B 2012; 182:921-34. [PMID: 22581071 DOI: 10.1007/s00360-012-0668-5] [Citation(s) in RCA: 135] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Revised: 04/11/2012] [Accepted: 04/14/2012] [Indexed: 11/27/2022]
Abstract
The oceanic carbonate system is changing rapidly due to rising atmospheric CO(2), with current levels expected to rise to between 750 and 1,000 μatm by 2100, and over 1,900 μatm by year 2300. The effects of elevated CO(2) on marine calcifying organisms have been extensively studied; however, effects of imminent CO(2) levels on teleost acid-base and respiratory physiology have yet to be examined. Examination of these physiological processes, using a paired experimental design, showed that 24 h exposure to 1,000 and 1,900 μatm CO(2) resulted in a characteristic compensated respiratory acidosis response in the gulf toadfish (Opsanus beta). Time course experiments showed the onset of acidosis occurred after 15 min of exposure to 1,900 and 1,000 μatm CO(2), with full compensation by 2 and 4 h, respectively. 1,900-μatm exposure also resulted in significantly increased intracellular white muscle pH after 24 h. No effect of 1,900 μatm was observed on branchial acid flux; however, exposure to hypercapnia and HCO(3)(-) free seawater compromised compensation. This suggests branchial HCO(3)(-) uptake rather than acid extrusion is part of the compensatory response to low-level hypercapnia. Exposure to 1,900 μatm resulted in downregulation in branchial carbonic anhydrase and slc4a2 expression, as well as decreased Na(+)/K(+) ATPase activity after 24 h of exposure. Infusion of bovine carbonic anhydrase had no effect on blood acid-base status during 1,900 μatm exposures, but eliminated the respiratory impacts of 1,000 μatm CO(2). The results of the current study clearly show that predicted near-future CO(2) levels impact respiratory gas transport and acid-base balance. While the full physiological impacts of increased blood HCO(3)(-) are not known, it seems likely that chronically elevated blood HCO(3)(-) levels could compromise several physiological systems and furthermore may explain recent reports of increased otolith growth during exposure to elevated CO(2).
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Affiliation(s)
- Andrew J Esbaugh
- Division of Marine Biology and Fisheries, Rosenstiel School of Marine and Atmospheric Science, University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149, USA.
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36
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Mechanism of sodium uptake in PNA negative MR cells from rainbow trout, Oncorhynchus mykiss as revealed by silver and copper inhibition. Comp Biochem Physiol A Mol Integr Physiol 2011; 159:234-41. [PMID: 21377535 DOI: 10.1016/j.cbpa.2011.02.025] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2010] [Revised: 02/23/2011] [Accepted: 02/24/2011] [Indexed: 02/07/2023]
Abstract
The rate of acid-stimulated and phenamil-sensitive sodium (Na(+)) uptake was measured in three different cell lineages: pavement cells (PVC), total mitochondrion-rich (MR) cell populations, and peanut lectin agglutinin-negative mitochondrion-rich cells (PNA(-) MR) isolated from the rainbow trout gill epithelium. Despite the presence of basal levels of Na(+) uptake in PVC, this transport was not enhanced by acidification, nor was it inhibited by independent treatment with bafilomycin (i.e., a V-type H(+)-ATPase inhibitor), phenamil (i.e., a specific inhibitor of ENaC), or Ag (a specific inhibitor of active Na(+) transport in fish). In contrast, Na(+) uptake in PNA(-) MR cells was increased by ~220% above basal levels following acidification of near 0.4 pH units in the presence of 1.0 mM external Na(+). Acid-stimulated Na(+) transport was entirely inhibited by both phenamil and bafilomycin. Silver (Ag) and copper (Cu), which are known to interfere with active Na(+) transport in fish, were also responsible for inhibiting acid stimulated Na(+) uptake in PNA(-) MR cells, but by themselves had no effect on basal Na(+) transport. Thus, we demonstrate that Ag specifically prevented acid-stimulated Na(+) uptake in PNA(-) MR cells in a dose-dependent manner. We also demonstrate rapid (<1 min) and significant inhibition of carbonic anhydrase (CA) by Ag in PNA(-) MR cells, but not in PVC. These data lend further support to the idea of a PNA(-) MR cell type as the primary site for Na(+) uptake in the freshwater (FW) gill phenotype of rainbow trout. Moreover, these findings provide support for the importance of intracellular protons in regulating the movement of Na(+) across the apical surface of the fish gill.
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37
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Gilmour KM, Collier CL, Dey CJ, Perry SF. Roles of cortisol and carbonic anhydrase in acid-base compensation in rainbow trout, Oncorhynchus mykiss. J Comp Physiol B 2010; 181:501-15. [PMID: 21136263 DOI: 10.1007/s00360-010-0540-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2010] [Revised: 11/09/2010] [Accepted: 11/17/2010] [Indexed: 02/06/2023]
Abstract
Fish compensate for acid-base disturbances primarily by modulating the branchial excretion of acid-base equivalents, with a supporting role played by adjustment of urinary acid excretion. The present study used metabolic acid-base disturbances in rainbow trout, Oncorhynchus mykiss, to evaluate the role played by cortisol in stimulating compensatory responses. Trout infused with acid (an iso-osmotic solution of 70 mmol L(-1) HCl), base (140 mmol L(-1) NaHCO(3)) or saline (140 mmol L(-1) NaCl) for 24 h exhibited significant elevation of circulating cortisol concentrations. Acid infusion significantly increased both branchial (by 328 μmol kg(-1) h(-1)) and urinary (by 5.9 μmol kg(-1) h(-1)) net acid excretion, compensatory responses that were eliminated by pre-treatment of trout with the cortisol synthesis inhibitor metyrapone (2-methyl-1,2-di-3-pyridyl-1-propanone). The significant decrease in net acid excretion (equivalent to enhanced base excretion) of 203 μmol kg(-1) h(-1) detected in base-infused trout was unaffected by metyrapone treatment. Acid- and base-infusions also were associated with significant changes in the relative mRNA expression of branchial and renal cytosolic carbonic anhydrase (tCAc) and renal membrane-linked CA IV (tCA IV). Cortisol treatment caused changes in CA gene expression that tended to parallel those observed with acid but not base infusion. For example, significant increases in renal relative tCA IV mRNA expression were detected in both acid-infused (~2x) and cortisol-treated (~10x) trout, whereas tCA IV mRNA expression was significantly reduced (~5x) in base-infused fish. Despite changes in CA gene expression in acid- or base-infused fish, neither acid nor base infusion affected CAc protein levels in the gill, but both caused significant increases in branchial CA activity. Cortisol treatment similarly increased branchial CA activity in the absence of an effect on branchial CAc protein expression. Taken together, these findings provide support for the hypothesis that in rainbow trout, cortisol is involved in mediating acid-base compensatory responses to a metabolic acidosis, and that cortisol exerts its effects at least in part through modulation of CA.
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Affiliation(s)
- K M Gilmour
- Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, ON, K1N 6N5, Canada.
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38
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Gilmour KM. Perspectives on carbonic anhydrase. Comp Biochem Physiol A Mol Integr Physiol 2010; 157:193-7. [PMID: 20541618 DOI: 10.1016/j.cbpa.2010.06.161] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2010] [Revised: 06/02/2010] [Accepted: 06/02/2010] [Indexed: 12/25/2022]
Abstract
In the years since Larimer and Schmidt-Nielsen published their examination of red blood cell (RBC) carbonic anhydrase (CA) activities as a function of body mass in mammals, our knowledge of CA has expanded dramatically. We are now aware of the diversity of CA isoforms and their implication in a wide array of physiological processes. The catalytic mechanism of CA has been described, and numerous compounds that function as activators or inhibitors of CA activity have been identified. CA is investigated as a diagnostic tumor marker, and CA inhibitors are used or emerging as clinical treatments for diseases as diverse as glaucoma, cancer and obesity. Yet despite the intensity of research effort over the last 50years and the wealth of information that has accumulated, the questions asked by Larimer and Schmidt-Nielsen remain relevant today - we still have much to learn about the patterns and physiological significance of interspecific differences in CA expression and activity.
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Affiliation(s)
- K M Gilmour
- Department of Biology, University of Ottawa, Ottawa, ON, Canada.
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39
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Gas transfer in dogfish: A unique model of CO2 excretion. Comp Biochem Physiol A Mol Integr Physiol 2010; 155:476-85. [DOI: 10.1016/j.cbpa.2009.10.043] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2009] [Revised: 10/26/2009] [Accepted: 10/29/2009] [Indexed: 11/23/2022]
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40
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Gilmour KM, Thomas K, Esbaugh AJ, Perry SF. Carbonic anhydrase expression and CO2 excretion during early development in zebrafish Danio rerio. ACTA ACUST UNITED AC 2010; 212:3837-45. [PMID: 19915126 DOI: 10.1242/jeb.034116] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Carbonic anhydrase (CA) is critical for CO2 excretion in adult fish, but little is known of the expression or function of CA during early development. The present study examined the hypothesis that, as rates of CO2 production increased during early development in zebrafish (Danio rerio), CA would become necessary for effective CO2 excretion, and that the pattern of CA expression during early development would reflect this transition. Real-time RT-PCR was used to examine the mRNA expression of the two main intracellular CA isoforms over a time course of early development ranging from 0 to 120 h post fertilization (h.p.f.). The mRNA expression of zCAb was generally higher than that of zCAc, particularly during the earliest stages of development. Rates of CO2 excretion increased approximately 15-fold from 24 to 48 h.p.f. whereas rates of O2 uptake increased only 6.7-fold over the same period, indicating a relative stimulation of CO2 excretion over O2 uptake. Treatment of 48 h.p.f. larvae with the CA inhibitor acetazolamide resulted in CO2 excretion rates that were 52% of the value in control larvae, a significant difference that occurred in the absence of any effect on O2 uptake. Antisense morpholino oligonucleotides were used to selectively knock down one or both of the main intracellular CA isoforms. Subsequent measurement of gas transfer rates at 48 h.p.f. indicated that CA knockdown caused a significant relative inhibition of CO2 excretion over O2 uptake, regardless of which cytosolic CA isoform was targeted for knockdown. These results suggest that between 24 h.p.f. and 48 h.p.f., developing zebrafish begin to rely on CA to meet requirements for increased CO2 excretion.
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Affiliation(s)
- K M Gilmour
- Department of Biology and Centre for Advanced Research in Environmental Genomics, University of Ottawa, Ottawa, ON, Canada.
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Cytosolic carbonic anhydrase in the Gulf toadfish is important for tolerance to hypersalinity. Comp Biochem Physiol A Mol Integr Physiol 2010; 156:169-75. [PMID: 20152924 DOI: 10.1016/j.cbpa.2010.01.018] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2009] [Revised: 01/22/2010] [Accepted: 01/24/2010] [Indexed: 11/21/2022]
Abstract
Carbonic anhydrase (CA) is a ubiquitous enzyme involved in acid-base regulation and osmoregulation. Many studies have demonstrated a role for this enzyme in fish osmoregulation in seawater as well as freshwater. However, to date CA responses of marine fish exposed to salinities exceeding seawater (approximately 35 ppt) have not been examined. Consequently, the aim of the present study was to examine CA expression and activity in osmoregulatory tissues of the Gulf Toadfish, Opsanus beta, following transfer to 60 ppt. A gene coding, for CAc of 1827 bp with an open reading frame of 260 amino acids was cloned and showed high expression in all intestinal segments and gills. CAc showed higher expression in posterior intestine and rectum than in anterior and mid intestine and in gills of fish exposed to 60 ppt for up to 4 days. The enzymatic activity, in contrast, was higher in all examined tissues two weeks following transfer to 60 ppt. Comparing early expression and later activity levels of acclimated fish reveals a very different response to hypersalinity among tissues. Results highlight a key role of CAc in osmoregulation especially in distal regions of the intestine; moreover, CAc play a role in the gill in hypersaline environments possibly supporting elevated branchial acid extrusion seen under such conditions.
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42
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Qin Z, Lewis JE, Perry SF. Zebrafish (Danio rerio) gill neuroepithelial cells are sensitive chemoreceptors for environmental CO2. J Physiol 2010; 588:861-72. [PMID: 20051495 DOI: 10.1113/jphysiol.2009.184739] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Adult zebrafish exhibit hyperventilatory responses to absolute environmental CO(2) levels as low as 0.13% ( mmHg), more than an order of magnitude lower than the typical arterial levels (40 mmHg) monitored by the mammalian carotid body. The sensory basis underlying the ability of fish to detect and respond to low ambient CO(2) levels is not clear. Here, we show that the neuroepithelial cells (NECs) of the zebrafish gill, known to sense O(2) levels, also respond to low levels of CO(2). An electrophysiological characterization of this response using both current and voltage clamp protocols revealed that for increasing CO(2) levels, a background K(+) channel was inhibited, resulting in a partial pressure-dependent depolarization of the NEC. To elucidate the signalling pathway underlying K(+) channel inhibition, we used immunocytochemistry to show that these NECs express carbonic anhydrase (CA), an enzyme involved in CO(2) sensing in the mammalian carotid body. Further, the NEC response to CO(2) (magnitude of membrane depolarization and time required to achieve maximal response), under conditions of constant pH, was reduced by 50% by the CA-inhibitor acetazolamide. This suggests that the CO(2) detection mechanism involves an intracellular sensor that is responsive to the rate of acidification associated with the hydration of CO(2) and which does not require a change of extracellular pH. Because some cells that were responsive to increasing also responded to hypoxia with membrane depolarization, the present results demonstrate that a subset of the NECs in the zebrafish gill are bimodal sensors of CO(2) and O(2).
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Affiliation(s)
- Z Qin
- Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, ON, Canada
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Abstract
SUMMARY
Carbonic anhydrase (CA) is the zinc metalloenzyme that catalyses the reversible reactions of CO2 with water. CA plays a crucial role in systemic acid–base regulation in fish by providing acid–base equivalents for exchange with the environment. Unlike air-breathing vertebrates, which frequently utilize alterations of breathing (respiratory compensation) to regulate acid–base status, acid–base balance in fish relies almost entirely upon the direct exchange of acid–base equivalents with the environment (metabolic compensation). The gill is the critical site of metabolic compensation, with the kidney playing a supporting role. At the gill, cytosolic CA catalyses the hydration of CO2 to H+ and HCO3– for export to the water. In the kidney, cytosolic and membrane-bound CA isoforms have been implicated in HCO3– reabsorption and urine acidification. In this review, the CA isoforms that have been identified to date in fish will be discussed together with their tissue localizations and roles in systemic acid–base regulation.
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Affiliation(s)
- K. M. Gilmour
- Department of Biology and Centre for Advanced Research in Environmental Genomics, University of Ottawa, Ottawa, ON, Canada
| | - S. F. Perry
- Department of Biology and Centre for Advanced Research in Environmental Genomics, University of Ottawa, Ottawa, ON, Canada
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Ivanis G, Braun M, Perry SF. Renal expression and localization of SLC9A3 sodium/hydrogen exchanger and its possible role in acid-base regulation in freshwater rainbow trout (Oncorhynchus mykiss). Am J Physiol Regul Integr Comp Physiol 2008; 295:R971-8. [PMID: 18667717 DOI: 10.1152/ajpregu.90328.2008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Experiments were performed to assess the possible involvement of the Na(+)/H(+) exchanger isoform 3 (NHE3; SLC9A3) in renal acid-base regulation in adult rainbow trout (Oncorhynchus mykiss). NHE3 mRNA was expressed at high levels in the kidney relative to its paralog, NHE2. The results of in situ hybridization demonstrated an abundance of NHE3 mRNA in renal tubules. The combination of immunocytochemistry and histological staining revealed that NHE3 was confined to the apical membrane of proximal tubules, where it was colocalized with the vacuolar-type H(+)-ATPase. Levels of NHE3 protein (assessed by Western blotting) were increased during hypercapnia, likely as a result of increased transcription, as indicated by increasing levels of NHE3 mRNA (as determined by real-time PCR). Plasma cortisol concentration was increased during hypercapnia, and administration of exogenous cortisol caused a marked increase in NHE3 mRNA and protein. Thus we speculate that the elevation of plasma cortisol during hypercapnia contributes to transcriptional activation of NHE3 that ultimately promotes acid-base regulation by stimulating H(+) secretion and HCO(3)(-) reabsorption.
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Affiliation(s)
- Goran Ivanis
- Dept. of Biology, Univ. of Ottawa, 30 Marie Curie, Ottawa, ONT K1N 6N5, Canada
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Lin TY, Liao BK, Horng JL, Yan JJ, Hsiao CD, Hwang PP. Carbonic anhydrase 2-like a and 15a are involved in acid-base regulation and Na+ uptake in zebrafish H+-ATPase-rich cells. Am J Physiol Cell Physiol 2008; 294:C1250-60. [PMID: 18322140 DOI: 10.1152/ajpcell.00021.2008] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
H(+)-ATPase-rich (HR) cells in zebrafish gills/skin were found to carry out Na+ uptake and acid-base regulation through a mechanism similar to that which occurs in mammalian proximal tubular cells. However, the roles of carbonic anhydrases (CAs) in this mechanism in zebrafish HR cells are still unclear. The present study used a functional genomic approach to identify 20 CA isoforms in zebrafish. By screening with whole mount in situ hybridization, only zca2-like a and zca15a were found to be expressed in specific groups of cells in zebrafish gills/skin, and further analyses by triple in situ hybridization and immunocytochemistry demonstrated specific colocalizations of the two zca isoforms in HR cells. Knockdown of zca2-like a caused no change in and knockdown of zca15a caused an increase in H+ activity at the apical surface of HR cells at 24 h postfertilization (hpf). Later, at 96 hpf, both the zca2-like a and zca15a morphants showed decreased H+ activity and increased Na+ uptake, with concomitant upregulation of znhe3b and downregulation of zatp6v1a (H+-ATPase A-subunit) expressions. Acclimation to both acidic and low-Na+ fresh water caused upregulation of zca15a expression but did not change the zca2-like a mRNA level in zebrafish gills. These results provide molecular physiological evidence to support the roles of these two zCA isoforms in Na+ uptake and acid-base regulation mechanisms in zebrafish HR cells.
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Affiliation(s)
- Tzung-Yi Lin
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan
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Marino S, Hayakawa K, Hatada K, Benfatto M, Rizzello A, Maffia M, Bubacco L. Structural features that govern enzymatic activity in carbonic anhydrase from a low-temperature adapted fish, Chionodraco hamatus. Biophys J 2007; 93:2781-90. [PMID: 17573429 PMCID: PMC1989726 DOI: 10.1529/biophysj.107.107540] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2007] [Accepted: 06/05/2007] [Indexed: 11/18/2022] Open
Abstract
The carbonic anhydrase (CA) family of zinc metalloenzymes includes many known isozymes that have different subcellular distributions. The study described here focuses on identification of the structural features that define low-temperature adaptation in a Chionodraco hamatus protein, both for the reaction center, at an atomic level, and for the tertiary structure of the protein. To this aim, an x-ray absorption near-edge spectroscopy/Minuit x-ray absorption near-edge spectroscopy analysis of the reaction center was undertaken for both a structurally characterized human CAII and CA of C. hamatus. Higher structural levels were analyzed by sequence comparison and homology modeling. To establish whether the structural insights acquired in fish CAs are general, theoretical models were generated by homology modeling for three temperate-climate-adapted fish CAs. The measured structural differences between the two proteins are discussed in terms of the differences in the electrostatic potential between human CAII and CA of C. hamatus. We conclude that modulation of the interaction between the catalytic water molecule and the zinc ion could depend on the effect of the electrostatic potential distribution.
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Affiliation(s)
- Stefano Marino
- Department of Biology, University of Padova, Padua, Italy
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Grosell M, Gilmour KM, Perry SF. Intestinal carbonic anhydrase, bicarbonate, and proton carriers play a role in the acclimation of rainbow trout to seawater. Am J Physiol Regul Integr Comp Physiol 2007; 293:R2099-111. [PMID: 17761514 DOI: 10.1152/ajpregu.00156.2007] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Abrupt transfer of rainbow trout from freshwater to 65% seawater caused transient disturbances in extracellular fluid ionic composition, but homeostasis was reestablished 48 h posttransfer. Intestinal fluid chemistry revealed early onset of drinking and slightly delayed intestinal water absorption that coincided with initiation of NaCl absorption and HCO(3)(-) secretion. Suggestive of involvement in osmoregulation, relative mRNA levels for vacuolar H(+)-ATPase (V-ATPase), Na(+)-K(+)-ATPase, Na(+)/H(+) exchanger 3 (NHE3), Na(+)-HCO(3)(-) cotransporter 1, and two carbonic anhydrase (CA) isoforms [a general cytosolic isoform trout cytoplasmic CA (tCAc) and an extracellular isoform trout membrane-bound CA type IV (tCAIV)], were increased transiently in the intestine following exposure to 65% seawater. Both tCAc and tCAIV proteins were localized to apical regions of the intestinal epithelium and exhibited elevated enzymatic activity after acclimation to 65% seawater. The V-ATPase was localized to both basolateral and apical regions and exhibited a 10-fold increase in enzymatic activity in fish acclimated to 65% seawater, suggesting a role in marine osmoregulation. The intestinal epithelium of rainbow trout acclimated to 65% seawater appears to be capable of both basolateral and apical H(+) extrusion, likely depending on osmoregulatory status and intestinal fluid chemistry.
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Affiliation(s)
- Martin Grosell
- Rosensteil School of Marine Atmospheric Sciences, University of Miami, FL 33149-1098, USA.
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Serrano L, Halanych KM, Henry RP. Salinity-stimulated changes in expression and activity of two carbonic anhydrase isoforms in the blue crabCallinectes sapidus. J Exp Biol 2007; 210:2320-32. [PMID: 17575037 DOI: 10.1242/jeb.005041] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
SUMMARYTwo isoforms of the enzyme carbonic anhydrase (CA) in the blue crab gill,CasCAg and CasCAc, were identified, sequenced, and found to match the membrane-associated and cytoplasmic isoforms, respectively. The membrane-associated isoform is present in much higher levels of mRNA expression in both anterior and posterior gills in crabs acclimated to high salinity (35 p.p.t.), but expression of the cytoplasmic isoform in the posterior gill undergoes a significantly greater degree of up-regulation after exposure to low salinity (15 p.p.t.). CasCAc has the largest scope of induction (100-fold) reported for any transport-related protein in the gill,and this may be necessary to overcome diffusion limitations between gill cytoplasm and the apical boundary layer. Furthermore, the timing of the changes in expression of CasCAc corresponds to the timing of the induction of protein-specific CA activity and CA protein concentration. No changes in CA mRNA expression or activity occur in the anterior gills. The pattern of up-regulation of expression of mRNA of the α-subunit of the Na+/K+-ATPase is similar to that for CasCAc, and both precede the establishment of the new acclimated physiological state of the crab in low salinity. A putative `housekeeping' gene, arginine kinase, also showed about a threefold increase in expression in response to low salinity,but only in the posterior gills. These results suggest that for studies of expression in crustacean gill tissue, a control tissue, such as the anterior gill, be used until an adequate control gene is identified.
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Affiliation(s)
- Laetitia Serrano
- Department of Biological Sciences, 101 Life Science Building, Auburn University, Auburn, AL 36849, USA
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Rizzello A, Ciardiello MA, Acierno R, Carratore V, Verri T, di Prisco G, Storelli C, Maffia M. Biochemical Characterization of a S-glutathionylated Carbonic Anhydrase Isolated from Gills of the Antarctic Icefish Chionodraco hamatus. Protein J 2007; 26:335-48. [PMID: 17510781 DOI: 10.1007/s10930-007-9076-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Gill cytoplasmic carbonic anhydrase of the haemoglobinless Antarctic icefish Chionodraco hamatus (Ice-CA) was directly sequenced and consists in 259 residues with an acetylated N-terminus. The molecular mass, deduced from the sequence, was 28.45 kDa, while mass spectrometry analysis of the native protein gave higher values. Treatment with dithiothreitol abolished this difference, indicating possible post-translational modifications. Isoelectric focusing analysis of Ice-CA suggested S-thiolation, which was identified as S-glutathionylation by immunostaining. Deglutathionylated Ice-CA maintained the anhydrase activity but showed higher susceptibility to hydrogen peroxide, suggesting that glutathione binding to Cys residues may have a role in the defence against oxidative damage. Ice-CA is characterized by lower thermal stability, higher activity and lower activation energy than its homologue gill CA of the temperate European eel, confirming the adaptation of the catalytic capacity to low temperatures. Alignment of Ice-CA with homologous enzymes from other fish shows high identity; the enzyme is grouped with a previously described fish CA monophyletic clade although Ice-CA shows several characteristics that can increase protein-solvent interaction and structural flexibility.
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Affiliation(s)
- Antonia Rizzello
- Laboratory of General Physiology, Department of Biological and Environmental Science and Technology, University of Salento, via Monteroni, 73100, Lecce, Italy
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Tresguerres M, Katoh F, Orr E, Parks SK, Goss GG. Chloride Uptake and Base Secretion in Freshwater Fish: A Transepithelial Ion‐Transport Metabolon? Physiol Biochem Zool 2006; 79:981-96. [PMID: 17041864 DOI: 10.1086/507658] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/30/2006] [Indexed: 11/04/2022]
Abstract
Despite all the efforts and technological advances during the last few decades, the cellular mechanisms for branchial chloride uptake in freshwater (FW) fish are still unclear. Although a tight 1 : 1 link with HCO-3 secretion has been established, not much is known about the identity of the ion-transporting proteins involved or the energizing steps that allow for the inward transport of Cl- against the concentration gradient. We propose a new model for Cl- uptake in FW fish whereby the combined action of an apical anion exchanger, cytoplasmic carbonic anhydrase, and basolateral V-type H+ -ATPase creates a local [HCO-3] high enough to energize Cl- uptake. Our model is based on analyses of structure-function relationships, reinterpretation of previous results, and novel observations about gill cell subtypes and immunolocalization of the V-H+ -ATPase.
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Affiliation(s)
- Martin Tresguerres
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta T5G 2E9, Canada.
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