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Morris C, Martins C, Zulian S, Smith DS, Brauner CJ, Wood CM. The effects of dissolved organic carbon and model compounds (DOC analogues) on diffusive water flux, oxygen consumption, nitrogenous waste excretion rates and gill transepithelial potential in Pacific sanddab (Citharichthys sordidus) at two salinities. J Comp Physiol B 2024:10.1007/s00360-024-01580-2. [PMID: 39245661 DOI: 10.1007/s00360-024-01580-2] [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: 05/30/2024] [Accepted: 08/16/2024] [Indexed: 09/10/2024]
Abstract
Many flatfish species are partially euryhaline, such as the Pacific sanddab which spawn and feed in highly dynamic estuaries ranging from seawater to near freshwater. With the rapid increase in saltwater invasion of freshwater habitats, it is very likely that in these estuaries, flatfish will be exposed to increasing levels of dissolved organic carbon (DOC) of freshwater origin at a range of salinities. As salinity fluctuations often coincide with changes in DOC concentration, two natural freshwater DOCs [Luther Marsh (LM, allochthonous) and Lake Ontario (LO, autochthonous) were investigated at salinities of 30 and 7.5 ppt. Optical characterization of the two natural DOC sources indicate salinity-dependent differences in their physicochemistry. LO and LM DOCs, as well as three model compounds [tannic acid (TA), sodium dodecyl sulfate (SDS) and bovine serum albumin (BSA)] representing key chemical moieties of DOC, were used to evaluate physiological effects on sanddabs. In the absence of added DOC, an acute decrease in salinity resulted in an increase in diffusive water flux (a proxy for transcellular water permeability), ammonia excretion and a change in TEP from positive (inside) to negative (inside). The effects of DOC (10 mg C L-1) were salinity and source-dependent, with generally more pronounced effects at 30 than 7.5 ppt, and greater potency of LM relative to LO. Both LM DOC and SDS increased diffusive water flux at 30 ppt but only SDS had an effect at 7.5 ppt. TA decreased ammonia excretion at 7.5 ppt. LO DOC decreased urea-N excretion at both salinities whereas the stimulatory effect of BSA occurred only at 30 ppt. Likewise, the effects of LM DOC and BSA to reduce TEP were present at 30 ppt but not 7.5 ppt. None of the treatments affected oxygen consumption rates. Our results demonstrate that DOCs and salinity interact to alter key physiological processes in marine flatfish, reflecting changes in both gill function and the physicochemistry of DOCs between 30 and 7.5 ppt.
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Affiliation(s)
- Carolyn Morris
- Bamfield Marine Sciences Centre, 100 Pachena Road, Bamfield, BC, V0R 1B0, Canada.
- Department of Zoology, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.
| | - Camila Martins
- Institute of Biological Sciences, Federal University of Rio Grande - FURG, Italia avenue, s/n, Carreiros, Rio Grande, 96203-900, RS, Brazil
| | - Samantha Zulian
- Department of Chemistry and Biochemistry, Wilfrid Laurier University, 75 University Ave. W., Waterloo, ON, N2L 3C5, Canada
| | - D Scott Smith
- Department of Chemistry and Biochemistry, Wilfrid Laurier University, 75 University Ave. W., Waterloo, ON, N2L 3C5, Canada
| | - Colin J Brauner
- Department of Zoology, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Chris M Wood
- Bamfield Marine Sciences Centre, 100 Pachena Road, Bamfield, BC, V0R 1B0, Canada
- Department of Zoology, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
- Department of Biology, McMaster University, 1280 Main St. West, Hamilton, ON, L8S 4K1, Canada
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Wind T, Ros A, Chucholl C, Roch S, Schumann M, Schulz C, Brinker A. Inland freshwater aquaculture in a warming world. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 934:173275. [PMID: 38754498 DOI: 10.1016/j.scitotenv.2024.173275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 05/11/2024] [Accepted: 05/13/2024] [Indexed: 05/18/2024]
Abstract
Climate change potentially threatens the sustainable production of highly valued cold-water fish species in flow-through systems, such as salmonids. By analysing the relationship of water temperature to hydrological characteristics, air temperature, solar exposure, and precipitation, this study predicted temperature dynamics of five temperate cold-water aquaculture facilities under four projected climate change scenarios. Air temperature was found to be directly associated with facility site water temperature, and based on rational assumptions, two of the five facilities were predicted to face critical warming by mid-century. Extreme precipitation events induced acute short-term increases in water temperature of up to 5 °C. Significantly lower warming, roughly equal to the projected climate change-induced increase, was seen with artificial shading lowering temperature by 1 °C. Complementary niche modelling revealed that 37-77 % of current cold-water facilities will likely incur suboptimal climate conditions by the end of the century. Shading of raceways, more efficient water use, and disease management are proposed as key actions to preserve cold-water aquaculture.
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Affiliation(s)
- Tamara Wind
- Fisheries Research Station of Baden-Wuerttemberg, Argenweg 50/1, 88085 Langenargen, Germany
| | - Albert Ros
- Fisheries Research Station of Baden-Wuerttemberg, Argenweg 50/1, 88085 Langenargen, Germany
| | - Christoph Chucholl
- Fisheries Research Station of Baden-Wuerttemberg, Argenweg 50/1, 88085 Langenargen, Germany
| | - Samuel Roch
- Fisheries Research Station of Baden-Wuerttemberg, Argenweg 50/1, 88085 Langenargen, Germany
| | - Mark Schumann
- Fisheries Research Station of Baden-Wuerttemberg, Argenweg 50/1, 88085 Langenargen, Germany
| | - Carsten Schulz
- Christian-Albrechts-University Kiel, Olshausenstraße 40, 24098 Kiel, Germany
| | - Alexander Brinker
- Fisheries Research Station of Baden-Wuerttemberg, Argenweg 50/1, 88085 Langenargen, Germany; University of Konstanz, Mainaustraße 252, 78464 Konstanz, Germany.
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Zimmer AM. Ammonia excretion by the fish gill: discoveries and ideas that shaped our current understanding. J Comp Physiol B 2024:10.1007/s00360-024-01561-5. [PMID: 38849577 DOI: 10.1007/s00360-024-01561-5] [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: 12/15/2023] [Revised: 03/06/2024] [Accepted: 05/15/2024] [Indexed: 06/09/2024]
Abstract
The fish gill serves many physiological functions, among which is the excretion of ammonia, the primary nitrogenous waste in most fishes. Although it is the end-product of nitrogen metabolism, ammonia serves many physiological functions including acting as an acid equivalent and as a counter-ion in mechanisms of ion regulation. Our current understanding of the mechanisms of ammonia excretion have been influenced by classic experimental work, clever mechanistic approaches, and modern molecular and genetic techniques. In this review, I will overview the history of the study of ammonia excretion by the gills of fishes, highlighting the important advancements that have shaped this field with a nearly 100-year history. The developmental and evolutionary implications of an ammonia and gill-dominated nitrogen regulation strategy in most fishes will also be discussed. Throughout the review, I point to areas in which more work is needed to push forward this field of research that continues to produce novel insights and discoveries that will undoubtedly shape our overall understanding of fish physiology.
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Affiliation(s)
- Alex M Zimmer
- Department of Biological Sciences, University of New Brunswick, 100 Tucker Park Road, Saint John, Saint John, New Brunswick, E2L 4L5, Canada.
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Gyamfi S, Edziyie RE, Obirikorang KA, Adjei-Boateng D, Skov PV. Nile tilapia (Oreochromis niloticus) show high tolerance to acute ammonia exposure but lose metabolic scope during prolonged exposure at low concentration. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2024; 271:106932. [PMID: 38692129 DOI: 10.1016/j.aquatox.2024.106932] [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: 01/04/2024] [Revised: 04/23/2024] [Accepted: 04/24/2024] [Indexed: 05/03/2024]
Abstract
Ammonia is a respiratory gas that is produced during the process of protein deamination. In the unionised form (NH3), it readily crosses biological membranes and is highly toxic to fish. In the present study we examined the effects of unionized ammonia (UIA), on the resting oxygen consumption (MO2), ventilation frequency (fV), heart rate (HR) and heart rate variability (HRV) in Nile tilapia (Oreochromis niloticus). Fish were either exposed to progressively increasing UIA concentrations, up to 97 µM over a 5 h period, or to a constant UIA level of 7 µM over a 24 h period. For both treatment groups resting MO2, HR and fV were recorded as physiological variables. Relative to the control group, the fish groups exposed to the incremental UIA levels did not exhibit significant changes in their MO2, HR and fV at UIA concentrations of 4, 10, 35, or 61 µM compared to control fish. Exposure to 97 µM UIA, however, elicited abrupt and significant downregulations (p < 0.05) in all three responses, as MO2, HR and fv decreased by 25, 54 and 76 % respectively, compared to control measurements. Heart rate became increasingly irregular with increasing UIA concentrations, and heart rate variability was significantly increased at 61 and 97 µM UIA. Prolonged exposure elicited significant changes at exposure 7 µM UIA. Standard (SMR) and maximum metabolic rate (MMR) were significantly reduced, as was the corresponding fV and HR. It is evident from this study that Nile tilapia is tolerant to short term exposure to UIA up to 61 µM but experience a significant metabolic change under conditions of prolonged UIA exposures even at low concentrations.
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Affiliation(s)
- Stephen Gyamfi
- Kwame Nkrumah University of Science and Technology, Department of Fisheries and Watershed Management, Kumasi, Ghana
| | - Regina Esi Edziyie
- Kwame Nkrumah University of Science and Technology, Department of Fisheries and Watershed Management, Kumasi, Ghana
| | - Kwasi Adu Obirikorang
- Kwame Nkrumah University of Science and Technology, Department of Fisheries and Watershed Management, Kumasi, Ghana
| | - Daniel Adjei-Boateng
- Kwame Nkrumah University of Science and Technology, Department of Fisheries and Watershed Management, Kumasi, Ghana
| | - Peter Vilhelm Skov
- Technical University of Denmark, DTU Aqua, Section for Aquaculture, The North Sea Research Centre, Hirtshals, Denmark
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Leonard EM, Porteus CS, Brink D, Milsom WK. Fish gill chemosensing: knowledge gaps and inconsistencies. J Comp Physiol B 2024:10.1007/s00360-024-01553-5. [PMID: 38758303 DOI: 10.1007/s00360-024-01553-5] [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: 12/08/2023] [Accepted: 04/04/2024] [Indexed: 05/18/2024]
Abstract
In this review, we explore the inconsistencies in the data and gaps in our knowledge that exist in what is currently known regarding gill chemosensors which drive the cardiorespiratory reflexes in fish. Although putative serotonergic neuroepithelial cells (NEC) dominate the literature, it is clear that other neurotransmitters are involved (adrenaline, noradrenaline, acetylcholine, purines, and dopamine). And although we assume that these agents act on neurons synapsing with the NECs or in the afferent or efferent limbs of the paths between chemosensors and central integration sites, this process remains elusive and may explain current discrepancies or species differences in the literature. To date it has been impossible to link the distribution of NECs to species sensitivity to different stimuli or fish lifestyles and while the gills have been shown to be the primary sensing site for respiratory gases, the location (gills, oro-branchial cavity or elsewhere) and orientation (external/water or internal/blood sensing) of the NECs are highly variable between species of water and air breathing fish. Much of what has been described so far comes from studies of hypoxic responses in fish, however, changes in CO2, ammonia and lactate have all been shown to elicit cardio-respiratory responses and all have been suggested to arise from stimulation of gill NECs. Our view of the role of NECs is broadening as we begin to understand the polymodal nature of these cells. We begin by presenting the fundamental picture of gill chemosensing that has developed, followed by some key unanswered questions about gill chemosensing in general.
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Affiliation(s)
- Erin M Leonard
- Department of Biology, Wilfrid Laurier University, Waterloo, ON, Canada
| | - Cosima S Porteus
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON, Canada.
| | - Deidre Brink
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
| | - William K Milsom
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
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Caneos WG, Shrivastava J, Ndugwa M, De Boeck G. Physiological responses of European sea bass (Dicentrarchus labrax) exposed to increased carbon dioxide and reduced seawater salinities. Mol Biol Rep 2024; 51:496. [PMID: 38587695 DOI: 10.1007/s11033-024-09460-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 03/19/2024] [Indexed: 04/09/2024]
Abstract
BACKGROUND The iono- and osmoregulatory capacities of marine teleosts, such as European sea bass (Dicentrarchus labrax) are expected to be challenged by high carbon dioxide exposure, and the adverse effects of elevated CO2 could be amplified when such fish migrate into less buffered hypo-osmotic estuarine environments. Therefore, the effects of increased CO2 on the physiological responses of European sea bass (Dicentrarchus labrax) acclimated to 32 ppt, 10 ppt and 2.5 ppt were investigated. METHODS Following acclimation to different salinities for two weeks, fish were exposed to present-day (400 µatm) and future (1000 µatm) atmospheric CO2 for 1, 3, 7 and 21 days. Blood pH, plasma ions (Na+, K+, Cl-), branchial mRNA expression of ion transporters such as Na+/K+-ATPase (NKA), Na+/K+/2Cl- co-transporters (NKCC) and ammonia transporters (e.g. Rhesus glycoproteins Rhbg, Rhcg1 and Rhcg2) were examined to understand the iono- and osmoregulatory consequences of elevated CO2. RESULTS A transient but significant increase in the blood pH of exposed fish acclimated at 10 ppt (day 1) and 2.5 ppt (day 21) was observed possibly due to an overshoot of the blood HCO3- accumulation while a significant reduction of blood pH was observed after 21 days at 2.5ppt. However, no change was seen at 32 ppt. Generally, Na + concentration of control fish was relatively higher at 10 ppt and lower at 2.5 ppt compared to 32 ppt control group at all sampling periods. Additionally, NKA was upregulated in gill of juvenile sea bass when acclimated to lower salinities compared to 32 ppt control group. CO2 exposure generally downregulated NKA mRNA expression at 32ppt (day 1), 10 ppt (days 3, 7 and 21) and 2.5ppt (days 1 and 7) and also a significant reduction of NKCC mRNA level of the exposed fish acclimated at 32 ppt (1-3 days) and 10 ppt (7-21 days) was observed. Furthermore, Rhesus glycoproteins were generally upregulated in the fish acclimated at lower salinities indicating a higher dependance on gill ammonia excretion. Increased CO2 led to a reduced expression of Rhbg and may therefore reduce ammonia excretion rate. CONCLUSION Juvenile sea bass were relatively successful in keeping acid base balance under an ocean acidification scenario. However, this came at a cost for ionoregulation with reduced NKA, NKCC and Rhbg expression rates as a consequence.
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Affiliation(s)
- Warren G Caneos
- ECOSPHERE, Department of Biology, University of Antwerp, Groenenborgerlaan 171, Antwerp, BE-2020, Belgium.
- Fisheries Department, College of Fisheries and Aquatic Sciences, Mindanao State University-Marawi, Marawi City, 9700, Philippines.
- Department of Biological Sciences, College of Science and Mathematics, Mindanao State University-Iligan Institute of Technology, Iligan City, 9200, Philippines.
| | - Jyotsna Shrivastava
- ECOSPHERE, Department of Biology, University of Antwerp, Groenenborgerlaan 171, Antwerp, BE-2020, Belgium
| | - Moses Ndugwa
- ECOSPHERE, Department of Biology, University of Antwerp, Groenenborgerlaan 171, Antwerp, BE-2020, Belgium
| | - Gudrun De Boeck
- ECOSPHERE, Department of Biology, University of Antwerp, Groenenborgerlaan 171, Antwerp, BE-2020, Belgium
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Zhao XF, Huang J, Li W, Wang SY, Liang LQ, Zhang LM, Liew HJ, Chang YM. Rh proteins and H + transporters involved in ammonia excretion in Amur Ide (Leuciscus waleckii) under high alkali exposure. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2024; 273:116160. [PMID: 38432157 DOI: 10.1016/j.ecoenv.2024.116160] [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: 08/03/2023] [Revised: 02/22/2024] [Accepted: 02/25/2024] [Indexed: 03/05/2024]
Abstract
High alkaline environment can lead to respiratory alkalosis and ammonia toxification to freshwater fish. However, the Amur ide (Leuciscus waleckii), which inhabits an extremely alkaline lake in China with titratable alkalinity up to 53.57 mM (pH 9.6) has developed special physiological and molecular mechanisms to adapt to such an environment. Nevertheless, how the Amur ide can maintain acid-base balance and perform ammonia detoxification effectively remains unclear. Therefore, this study was designed to study the ammonia excretion rate (Tamm), total nitrogen accumulation in blood and tissues, including identification, expression, and localization of ammonia-related transporters in gills of both the alkali and freshwater forms of the Amur ide. The results showed that the freshwater form Amur ide does not have a perfect ammonia excretion mechanism exposed to high-alkaline condition. Nevertheless, the alkali form of Amur ide was able to excrete ammonia better than freshwater from Amur ide, which was facilitated by the ionocytes transporters (Rhbg, Rhcg1, Na+/H+ exchanger 2 (NHE2), and V-type H+ ATPase (VHA)) in the gills. Converting ammonia into urea served as an ammonia detoxication strategy to reduced endogenous ammonia accumulation under high-alkaline environment.
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Affiliation(s)
- Xue Fei Zhao
- National and Local Joint Engineering Laboratory for Freshwater Fish Breeding, Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin 150070, China; College of Wildlife and Protected Area, Northeast Forestry University, Harbin 150040, China
| | - Jing Huang
- National and Local Joint Engineering Laboratory for Freshwater Fish Breeding, Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin 150070, China
| | - Wen Li
- National and Local Joint Engineering Laboratory for Freshwater Fish Breeding, Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin 150070, China; College of Fisheries and Life Science, Shanghai Ocean University, Shanghai 2000, China
| | - Shuang Yi Wang
- National and Local Joint Engineering Laboratory for Freshwater Fish Breeding, Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin 150070, China; BGI Genomics, BGI-Shenzhen, Shenzhen, Guangdong 518083, China
| | - Li Qun Liang
- National and Local Joint Engineering Laboratory for Freshwater Fish Breeding, Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin 150070, China
| | - Li Min Zhang
- National and Local Joint Engineering Laboratory for Freshwater Fish Breeding, Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin 150070, China
| | - Hon Jung Liew
- Higher Institution Center of Excellence (HICoE), Institute of Tropical Aquaculture and Fisheries, Universiti of Malaysia Terengganu, Kuala Nerus, Terengganu 21030, Malaysia
| | - Yu Mei Chang
- National and Local Joint Engineering Laboratory for Freshwater Fish Breeding, Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin 150070, China.
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Quijada-Rodriguez AR, Fehsenfeld S, Marini AM, Wilson JM, Nash MT, Sachs M, Towle DW, Weihrauch D. Branchial CO 2 and ammonia excretion in crustaceans: Involvement of an apical Rhesus-like glycoprotein. Acta Physiol (Oxf) 2024; 240:e14078. [PMID: 38205922 DOI: 10.1111/apha.14078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 10/13/2023] [Accepted: 12/14/2023] [Indexed: 01/12/2024]
Abstract
AIM To determine whether the crustacean Rh1 protein functions as a dual CO2 /ammonia transporter and investigate its role in branchial ammonia excretion and acid-base regulation. METHODS Sequence analysis of decapod Rh1 proteins was used to determine the conservation of amino acid residues putatively involved in ammonia transport and CO2 binding in human and bacterial Rh proteins. Using the Carcinus maenas Rh1 protein (CmRh1) as a representative of decapod Rh1 proteins, we test the ammonia and CO2 transport capabilities of CmRh1 through heterologous expression in yeast and Xenopus oocytes coupled with site-directed mutagenesis. Quantitative PCR was used to assess the distribution of CmRh1 mRNA in various tissues. Western blotting was used to assess CmRh1 protein expression changes in response to high environmental ammonia and CO2 . Further, immunohistochemistry was used to assess sub-cellular localization of CmRh1 and a membrane-bound carbonic anhydrase (CmCAg). RESULTS Sequence analysis of decapod Rh proteins revealed high conservation of several amino acid residues putatively involved in conducting ammonia transport and CO2 binding. Expression of CmRh1 in Xenopus oocytes enhanced both ammonia and CO2 transport which was nullified in CmRh1 D180N mutant oocytes. Transport of the ammonia analog methylamine by CmRh1 is dependent on both ionized and un-ionized ammonia/methylamine species. CmRh1 was co-localized with CmCAg to the apical membrane of the crustacean gill and only experienced decreased protein expression in the anterior gills when exposed to high environmental ammonia. CONCLUSION CmRh1 is the first identified apical transporter-mediated route for ammonia and CO2 excretion in the crustacean gill. Our findings shed further light on the potential universality of dual ammonia and CO2 transport capacity of Rhesus glycoproteins in both vertebrates and invertebrates.
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Affiliation(s)
- Alex R Quijada-Rodriguez
- Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
- Department of Biology, Wilfrid Laurier University, Waterloo, Ontario, Canada
| | - Sandra Fehsenfeld
- Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
- Département de biologie, chimie et géographie, Université du Québec à Rimouski, Rimouski, Quebec, Canada
| | - Anna-Maria Marini
- Biology of Membrane Transport Laboratory, Molecular Biology Department, Université Libre de Bruxelles, Bruxelles, Belgium
- WELBIO, Wavre, Belgium
| | - Jonathan M Wilson
- Department of Biology, Wilfrid Laurier University, Waterloo, Ontario, Canada
| | - Mikyla T Nash
- Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Maria Sachs
- Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - David W Towle
- Mount Desert Island Biological Laboratory, Salisbury Cove, Maine, USA
| | - Dirk Weihrauch
- Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
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Williamson G, Harris T, Bizior A, Hoskisson PA, Pritchard L, Javelle A. Biological ammonium transporters: evolution and diversification. FEBS J 2024. [PMID: 38265636 DOI: 10.1111/febs.17059] [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: 09/26/2023] [Revised: 12/14/2023] [Accepted: 01/09/2024] [Indexed: 01/25/2024]
Abstract
Although ammonium is the preferred nitrogen source for microbes and plants, in animal cells it is a toxic product of nitrogen metabolism that needs to be excreted. Thus, ammonium movement across biological membranes, whether for uptake or excretion, is a fundamental and ubiquitous biological process catalysed by the superfamily of the Amt/Mep/Rh transporters. A remarkable feature of the Amt/Mep/Rh family is that they are ubiquitous and, despite sharing low amino acid sequence identity, are highly structurally conserved. Despite sharing a common structure, these proteins have become involved in a diverse range of physiological process spanning all domains of life, with reports describing their involvement in diverse biological processes being published regularly. In this context, we exhaustively present their range of biological roles across the domains of life and after explore current hypotheses concerning their evolution to help to understand how and why the conserved structure fulfils diverse physiological functions.
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Affiliation(s)
- Gordon Williamson
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
| | - Thomas Harris
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
| | - Adriana Bizior
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
| | - Paul Alan Hoskisson
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
| | - Leighton Pritchard
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
| | - Arnaud Javelle
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
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10
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Takvam M, Wood CM, Kryvi H, Nilsen TO. Role of the kidneys in acid-base regulation and ammonia excretion in freshwater and seawater fish: implications for nephrocalcinosis. Front Physiol 2023; 14:1226068. [PMID: 37457024 PMCID: PMC10339814 DOI: 10.3389/fphys.2023.1226068] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2023] [Accepted: 06/12/2023] [Indexed: 07/18/2023] Open
Abstract
Maintaining normal pH levels in the body fluids is essential for homeostasis and represents one of the most tightly regulated physiological processes among vertebrates. Fish are generally ammoniotelic and inhabit diverse aquatic environments that present many respiratory, acidifying, alkalinizing, ionic and osmotic stressors to which they are able to adapt. They have evolved flexible strategies for the regulation of acid-base equivalents (H+, NH4 +, OH- and HCO3 -), ammonia and phosphate to cope with these stressors. The gills are the main regulatory organ, while the kidneys play an important, often overlooked accessory role in acid-base regulation. Here we outline the kidneys role in regulation of acid-base equivalents and two of the key 'urinary buffers', ammonia and phosphate, by integrating known aspects of renal physiology with recent advances in the molecular and cellular physiology of membrane transport systems in the teleost kidneys. The renal transporters (NHE3, NBC1, AE1, SLC26A6) and enzymes (V-type H+ATPase, CAc, CA IV, ammoniagenic enzymes) involved in H+ secretion, bicarbonate reabsorption, and the net excretion of acidic and basic equivalents, ammonia, and inorganic phosphate are addressed. The role of sodium-phosphate cotransporter (Slc34a2b) and rhesus (Rh) glycoproteins (ammonia channels) in conjunction with apical V-type H+ ATPase and NHE3 exchangers in these processes are also explored. Nephrocalcinosis is an inflammation-like disorder due to the precipitation of calcareous material in the kidneys, and is listed as one of the most prevalent pathologies in land-based production of salmonids in recirculating aquaculture systems. The causative links underlying the pathogenesis and etiology of nephrocalcinosis in teleosts is speculative at best, but acid-base perturbation is probably a central pathophysiological cause. Relevant risk factors associated with nephrocalcinosis are hypercapnia and hyperoxia in the culture water. These raise internal CO2 levels in the fish, triggering complex branchial and renal acid-base compensations which may promote formation of kidney stones. However, increased salt loads through the rearing water and the feed may increase the prevalence of nephrocalcinosis. An increased understanding of the kidneys role in acid-base and ion regulation and how this relates to renal diseases such as nephrocalcinosis will have applied relevance for the biologist and aquaculturist alike.
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Affiliation(s)
- Marius Takvam
- Department of Biological Sciences, University of Bergen, Bergen, Norway
| | - Chris M. Wood
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
| | - H. Kryvi
- Department of Biological Sciences, University of Bergen, Bergen, Norway
| | - Tom O. Nilsen
- Department of Biological Sciences, University of Bergen, Bergen, Norway
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Wang S, Tian J, Jiang X, Li C, Ge Y, Hu X, Cheng L, Shi X, Shi L, Jia Z. Effects of Different Dietary Protein Levels on the Growth Performance, Physicochemical Indexes, Quality, and Molecular Expression of Yellow River Carp (Cyprinus carpio haematopterus). Animals (Basel) 2023; 13:ani13071237. [PMID: 37048493 PMCID: PMC10093604 DOI: 10.3390/ani13071237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 03/14/2023] [Accepted: 03/29/2023] [Indexed: 04/05/2023] Open
Abstract
A 12-week rearing trial was carried out to estimate effects on the growth performance, physicochemical indexes, quality, and the molecular expression of Yellow River Carp (Cyprinus carpio haematopterus) using five practical diets, including dietary protein levels of 220, 250, 280, 310, and 340 g/kg. The results illustrated that the fish’s weight gain (WG) and specific growth rate (SGR) were significantly influenced, with an ascending dietary protein level of up to 250 g/kg (p < 0.05). The carp muscle contents of total saturated fatty acids (∑SFA), monounsaturated fatty acids (∑MUFA), polyunsaturated fatty acids (∑PUFA), and fatty acids (∑FA) decreased significantly with the ascending dietary protein levels, except for the 250 g/kg protein diet (p < 0.05). Only the glutamic acid and total essential amino acid (∑EAA) contents were significantly influenced by the ascending dietary protein levels (p < 0.05). The relative GH expression of the carp muscle significantly decreased with the increase in the dietary protein level up to 310 g/kg, and then it significantly increased (p < 0.05). In the intestines, the peak relative TOR expression was observed on the 220 g/kg protein diet, while the relative 4EBP1 expression was significantly influenced by the dietary protein level up to 250 g/kg (p < 0.05). In the muscle, the peak relative TOR and 4EBP1 expression levels were observed on the 250 g/kg protein diet. In gills, the lowest relative Rhag, Rhbg, and Rhcg1 expression levels were observed on the 250 g/kg protein diet. Based on all of the aforementioned results, the optimal dietary protein level for Cyprinus carpio haematopterus (160.24 ± 15.56 g) is 250–280 g/kg.
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Affiliation(s)
- Shihui Wang
- National and Local Joint Engineering Laboratory for Freshwater Fish Breeding, Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin 150070, China
- Key Open Laboratory of Cold Water Fish Germplasm Resources and Breeding of Heilongjiang Province, Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin 150070, China
| | - Jingwen Tian
- National and Local Joint Engineering Laboratory for Freshwater Fish Breeding, Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin 150070, China
- Key Laboratory of Freshwater Aquatic Biotechnology and Breeding, Ministry of Agriculture and Rural Affairs, Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin 150070, China
| | - Xiaona Jiang
- National and Local Joint Engineering Laboratory for Freshwater Fish Breeding, Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin 150070, China
- Key Laboratory of Freshwater Aquatic Biotechnology and Breeding, Ministry of Agriculture and Rural Affairs, Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin 150070, China
| | - Chitao Li
- National and Local Joint Engineering Laboratory for Freshwater Fish Breeding, Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin 150070, China
- Key Laboratory of Freshwater Aquatic Biotechnology and Breeding, Ministry of Agriculture and Rural Affairs, Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin 150070, China
| | - Yanlong Ge
- National and Local Joint Engineering Laboratory for Freshwater Fish Breeding, Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin 150070, China
- Key Laboratory of Freshwater Aquatic Biotechnology and Breeding, Ministry of Agriculture and Rural Affairs, Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin 150070, China
| | - Xuesong Hu
- National and Local Joint Engineering Laboratory for Freshwater Fish Breeding, Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin 150070, China
- Key Laboratory of Freshwater Aquatic Biotechnology and Breeding, Ministry of Agriculture and Rural Affairs, Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin 150070, China
| | - Lei Cheng
- National and Local Joint Engineering Laboratory for Freshwater Fish Breeding, Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin 150070, China
- Key Laboratory of Freshwater Aquatic Biotechnology and Breeding, Ministry of Agriculture and Rural Affairs, Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin 150070, China
| | - Xiaodan Shi
- National and Local Joint Engineering Laboratory for Freshwater Fish Breeding, Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin 150070, China
- Key Laboratory of Freshwater Aquatic Biotechnology and Breeding, Ministry of Agriculture and Rural Affairs, Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin 150070, China
| | - Lianyu Shi
- National and Local Joint Engineering Laboratory for Freshwater Fish Breeding, Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin 150070, China
- Key Laboratory of Freshwater Aquatic Biotechnology and Breeding, Ministry of Agriculture and Rural Affairs, Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin 150070, China
| | - Zhiying Jia
- National and Local Joint Engineering Laboratory for Freshwater Fish Breeding, Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin 150070, China
- Key Laboratory of Freshwater Aquatic Biotechnology and Breeding, Ministry of Agriculture and Rural Affairs, Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin 150070, China
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12
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Sachs M, Quijada-Rodriguez AR, Hans S, Weihrauch D. Characterization of two novel ammonia transporters, HIAT1α and HIAT1β, in the American Horseshoe Crab, Limulus polyphemus. Comp Biochem Physiol A Mol Integr Physiol 2023; 278:111365. [PMID: 36577451 DOI: 10.1016/j.cbpa.2022.111365] [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: 11/25/2022] [Revised: 12/23/2022] [Accepted: 12/23/2022] [Indexed: 12/26/2022]
Abstract
The American horseshoe crab, Limulus polyphemus, excretes nitrogenous waste in the form of toxic ammonia across their book gills. The mechanism of this branchial excretion is yet unknown. In the current study, two isoforms of a novel ammonia transporter, LpHIAT1α and LpHIAT1β, have been identified in L. polyphemus. Both isoforms have 12 predicted transmembrane regions and share 82.7% of amino acid identity to each other, and 77-86% amino acid homology to HIAT1 found in fish and crustaceans. In L. polyphemus, both isoforms were expressed in the gills, coxal glands, and brain. Slightly higher mRNA expression levels of LpHIAT1α were observed in the peripheral mitochondria-poor region of the gill (PMPA), central mitochondria-rich region of the gill (CMRA), and brain compared to the LpHIAT1β isoform. A functional expression analysis of LpHIAT1α and LpHIAT1β in Xenopus laevis oocytes resulted in a significantly lower uptake of the radiolabeled ammonia analogue 3H-methylamine when compared to controls, indicating an ammonia excretory function of the proteins. Exposure to elevated environmental ammonia (HEA, 1 mmol l-1 NH4Cl) caused an increase in mRNA expression of LpHIAT1β in the ion-conductive ventral gill half. High mRNA expression of both isoforms in the brain, and the observation that LpHIAT1α and LpHIAT1β likely mediate cellular ammonia excretion, suggests that these highly conserved ammonia transporters have an important housekeeping function in cellular ammonia elimination.
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Affiliation(s)
- Maria Sachs
- University of Manitoba, Department of Biological Sciences, 66 Chancellors Circle, Winnipeg, MB R3T 2N2, Canada
| | - Alex R Quijada-Rodriguez
- University of Manitoba, Department of Biological Sciences, 66 Chancellors Circle, Winnipeg, MB R3T 2N2, Canada
| | - Stephanie Hans
- University of Manitoba, Department of Biological Sciences, 66 Chancellors Circle, Winnipeg, MB R3T 2N2, Canada
| | - Dirk Weihrauch
- University of Manitoba, Department of Biological Sciences, 66 Chancellors Circle, Winnipeg, MB R3T 2N2, Canada.
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13
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Kumagai S, Watanabe E, Hayashi N, Kimura Y, Kamiya T, Nagashima A, Ushio K, Imaizumi G, Kim J, Munakata K, Umezawa T, Hirose S, Kasai K, Fujiwara T, Romero MF, Kato A. Boric acid transport activity of marine teleost aquaporins expressed in Xenopus oocytes. Physiol Rep 2023; 11:e15655. [PMID: 36967473 PMCID: PMC10040401 DOI: 10.14814/phy2.15655] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 03/06/2023] [Accepted: 03/09/2023] [Indexed: 03/29/2023] Open
Abstract
Marine teleosts ingest large amounts of seawater containing various ions, including 0.4 mM boric acid, which can accumulate at toxic levels in the body. However, the molecular mechanisms by which marine teleosts absorb and excrete boric acid are not well understood. Aquaporins (Aqps) are homologous to the nodulin-like intrinsic protein (NIP) family of plant boric acid channels. To investigate the potential roles of Aqps on boric acid transport across the plasma membrane in marine teleosts, we analyzed the function of Aqps of Japanese pufferfish (Takifugu rubripes) expressed in Xenopus laevis oocytes. Takifugu genome database contains 16 genes encoding the aquaporin family members (aqp0a, aqp0b, aqp1aa, aqp1ab, aqp3a, aqp4a, aqp7, aqp8bb, aqp9a, aqp9b, aqp10aa, aqp10bb, aqp11a, aqp11b, aqp12, and aqp14). When T. rubripes Aqps (TrAqps) were expressed in X. laevis oocytes, a swelling assay showed that boric acid permeability was significantly increased in oocytes expressing TrAqp3a, 7, 8bb, 9a, and 9b. The influx of boric acid into these oocytes was also confirmed by elemental quantification. Electrophysiological analysis using a pH microelectrode showed that these TrAqps increase B(OH)3 permeability. These results indicate that TrAqp3a, 7, 8bb, 9a, and 9b act as boric acid transport systems, likely as channels, in marine teleosts.
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Affiliation(s)
- Shiori Kumagai
- School of Life Science and TechnologyTokyo Institute of TechnologyYokohamaJapan
| | - Erika Watanabe
- School of Life Science and TechnologyTokyo Institute of TechnologyYokohamaJapan
| | - Naoko Hayashi
- Graduate School of Bioscience and BiotechnologyTokyo Institute of TechnologyYokohamaJapan
| | - Yuuri Kimura
- Graduate School of Bioscience and BiotechnologyTokyo Institute of TechnologyYokohamaJapan
| | - Takehiro Kamiya
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life SciencesThe University of TokyoTokyoJapan
| | - Ayumi Nagashima
- School of Life Science and TechnologyTokyo Institute of TechnologyYokohamaJapan
| | - Kazutaka Ushio
- School of Life Science and TechnologyTokyo Institute of TechnologyYokohamaJapan
| | - Genki Imaizumi
- School of Life Science and TechnologyTokyo Institute of TechnologyYokohamaJapan
| | - Juhyun Kim
- School of Life Science and TechnologyTokyo Institute of TechnologyYokohamaJapan
| | - Keijiro Munakata
- School of Life Science and TechnologyTokyo Institute of TechnologyYokohamaJapan
- Graduate School of Bioscience and BiotechnologyTokyo Institute of TechnologyYokohamaJapan
| | - Takahiro Umezawa
- Graduate School of Bioscience and BiotechnologyTokyo Institute of TechnologyYokohamaJapan
| | - Shigehisa Hirose
- Graduate School of Bioscience and BiotechnologyTokyo Institute of TechnologyYokohamaJapan
| | - Koji Kasai
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life SciencesThe University of TokyoTokyoJapan
| | - Toru Fujiwara
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life SciencesThe University of TokyoTokyoJapan
| | - Michael F. Romero
- Department of Physiology and Biomedical EngineeringMayo Clinic College of MedicineRochesterMinnesotaUnited States
- Nephrology & HypertensionMayo Clinic College of MedicineRochesterMinnesotaUnited States
- O'Brien Urology Research CenterMayo Clinic College of MedicineRochesterMinnesotaUnited States
| | - Akira Kato
- School of Life Science and TechnologyTokyo Institute of TechnologyYokohamaJapan
- Graduate School of Bioscience and BiotechnologyTokyo Institute of TechnologyYokohamaJapan
- Department of Physiology and Biomedical EngineeringMayo Clinic College of MedicineRochesterMinnesotaUnited States
- Center for Biological Resources and InformaticsTokyo Institute of TechnologyYokohamaJapan
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14
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Mes W, Kersten P, Maas RM, Eding EH, Jetten MSM, Siepel H, Lücker S, Gorissen M, Van Kessel MAHJ. Effects of demand-feeding and dietary protein level on nitrogen metabolism and symbiont dinitrogen gas production of common carp ( Cyprinus carpio, L.). Front Physiol 2023; 14:1111404. [PMID: 36824463 PMCID: PMC9941540 DOI: 10.3389/fphys.2023.1111404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 01/27/2023] [Indexed: 02/10/2023] Open
Abstract
Ammonia accumulation is a major challenge in intensive aquaculture, where fish are fed protein-rich diets in large rations, resulting in increased ammonia production when amino acids are metabolized as energy source. Ammonia is primarily excreted via the gills, which have been found to harbor nitrogen-cycle bacteria that convert ammonia into dinitrogen gas (N2) and therefore present a potential in situ detoxifying mechanism. Here, we determined the impact of feeding strategies (demand-feeding and batch-feeding) with two dietary protein levels on growth, nitrogen excretion, and nitrogen metabolism in common carp (Cyprinus carpio, L.) in a 3-week feeding experiment. Demand-fed fish exhibited significantly higher growth rates, though with lower feed efficiency. When corrected for feed intake, nitrogen excretion was not impacted by feeding strategy or dietary protein, but demand-fed fish had significantly more nitrogen unaccounted for in the nitrogen balance and less retained nitrogen. N2 production of individual fish was measured in all experimental groups, and production rates were in the same order of magnitude as the amount of nitrogen unaccounted for, thus potentially explaining the missing nitrogen in the balance. N2 production by carp was also observed when groups of fish were kept in metabolic chambers. Demand feeding furthermore caused a significant increase in hepatic glutamate dehydrogenase activities, indicating elevated ammonia production. However, branchial ammonia transporter expression levels in these animals were stable or decreased. Together, our results suggest that feeding strategy impacts fish growth and nitrogen metabolism, and that conversion of ammonia to N2 by nitrogen cycle bacteria in the gills may explain the unaccounted nitrogen in the balance.
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Affiliation(s)
- Wouter Mes
- Department of Animal Ecology and Physiology, Radboud Institute for Biological and Ecological Sciences, Radboud University, Nijmegen, Netherlands.,Department of Microbiology, Radboud Institute for Biological and Ecological Sciences, Radboud University, Nijmegen, Netherlands
| | - Philippe Kersten
- Department of Animal Ecology and Physiology, Radboud Institute for Biological and Ecological Sciences, Radboud University, Nijmegen, Netherlands
| | - Roel M Maas
- Aquaculture and Fisheries Group, Wageningen University and Research, Wageningen, Netherlands
| | - Ep H Eding
- Aquaculture and Fisheries Group, Wageningen University and Research, Wageningen, Netherlands
| | - Mike S M Jetten
- Department of Microbiology, Radboud Institute for Biological and Ecological Sciences, Radboud University, Nijmegen, Netherlands
| | - Henk Siepel
- Department of Animal Ecology and Physiology, Radboud Institute for Biological and Ecological Sciences, Radboud University, Nijmegen, Netherlands
| | - Sebastian Lücker
- Department of Microbiology, Radboud Institute for Biological and Ecological Sciences, Radboud University, Nijmegen, Netherlands
| | - Marnix Gorissen
- Department of Animal Ecology and Physiology, Radboud Institute for Biological and Ecological Sciences, Radboud University, Nijmegen, Netherlands
| | - Maartje A H J Van Kessel
- Department of Microbiology, Radboud Institute for Biological and Ecological Sciences, Radboud University, Nijmegen, Netherlands
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15
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Heuer RM, Wang Y, Pasparakis C, Zhang W, Scholey V, Margulies D, Grosell M. Effects of elevated CO 2 on metabolic rate and nitrogenous waste handling in the early life stages of yellowfin tuna (Thunnus albacares). Comp Biochem Physiol A Mol Integr Physiol 2023; 280:111398. [PMID: 36775093 DOI: 10.1016/j.cbpa.2023.111398] [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: 01/26/2022] [Revised: 02/05/2023] [Accepted: 02/05/2023] [Indexed: 02/12/2023]
Abstract
Ocean acidification is predicted to have a wide range of impacts on fish, but there has been little focus on broad-ranging pelagic fish species. Early life stages of fish are thought to be particularly susceptible to CO2 exposure, since acid-base regulatory faculties may not be fully developed. We obtained yellowfin tuna (Thunnus albacares) from a captive spawning broodstock population and exposed them to control or 1900 μatm CO2 through the first three days of development as embryos transitioned into yolk sac larvae. Metabolic rate, yolk sac depletion, and oil globule depletion were measured to assess overall energy usage. To determine if CO2 altered protein catabolism, tissue nitrogen content and nitrogenous waste excretion were quantified. CO2 exposure did not significantly impact embryonic metabolic rate, yolk sac depletion, or oil globule depletion, however, there was a significant decrease in metabolic rate at the latest measured yolk sac larval stage (36 h post fertilization). CO2-exposure led to a significant increase in nitrogenous waste excretion in larvae, but there were no differences in nitrogen tissue accumulation. Nitrogenous waste accumulated in embryos as they developed but decreased after hatch, coinciding with a large increase in nitrogenous waste excretion and increased metabolic rate in newly hatched larvae. Our results provide insight into how yellowfin tuna are impacted by increases in CO2 in early development, but more research with higher levels of replication is needed to better understand long-term impacts and acid-base regulatory mechanisms in this important pelagic fish.
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Affiliation(s)
- Rachael M Heuer
- University of Miami, Rosenstiel School of Marine and Atmospheric Science, 4600 Rickenbacker Causeway, Miami, FL 33149, USA.
| | - Yadong Wang
- University of Miami, Rosenstiel School of Marine and Atmospheric Science, 4600 Rickenbacker Causeway, Miami, FL 33149, USA
| | - Christina Pasparakis
- University of Miami, Rosenstiel School of Marine and Atmospheric Science, 4600 Rickenbacker Causeway, Miami, FL 33149, USA. https://twitter.com/ChristinaP47
| | - Wenlong Zhang
- University of Miami, Rosenstiel School of Marine and Atmospheric Science, 4600 Rickenbacker Causeway, Miami, FL 33149, USA
| | - Vernon Scholey
- Inter-American Tropical Tuna Commission, Achotines Laboratory, Las Tablas, Los Santos Province, Panama
| | - Daniel Margulies
- Inter-American Tropical Tuna Commission, 8901 La Jolla Shores Drive, La Jolla, California, USA
| | - Martin Grosell
- University of Miami, Rosenstiel School of Marine and Atmospheric Science, 4600 Rickenbacker Causeway, Miami, FL 33149, USA. https://twitter.com/MartinGrosell
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16
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Huang M, Shang ZH, Wu MX, Zhang LJ, Zhang YL. Regulation of Rhesus glycoprotein-related genes in large-scale loach Paramisgurnus dabryanus during ammonia loading. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2022; 244:114077. [PMID: 36108439 DOI: 10.1016/j.ecoenv.2022.114077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 09/04/2022] [Accepted: 09/10/2022] [Indexed: 06/15/2023]
Abstract
Waterborne ammonia is one of the crucial issues that limited production and animal health in aquaculture. Ammonia-tolerant varieties are highly desired in intensive fish farming. Screening for the key regulatory genes of ammonia tolerance is essential for variety breeding. According to the previous hypothesis, Rh glycoproteins play an important role in ammonia excretion in teleosts. However, the ammonia defensive mechanisms are not well described at present for large-scale loach (Paramisgurnus dabryanus), a typical air-breathing and commercially important fish in East Asia. Here we show that the transcription of Rh glycoprotein-related genes was significantly affected by ammonia exposure in this species. Probit analysis showed that 96 h-LC50 of NH4Cl at 23 ℃ and pH 7.2 was 92.64 mmol/L. A significant increase of Rhcg expression in gills was observed after 48 h of 60 mmol/L and 36 h of 80 mmol/L NH4Cl exposure, suggesting that Rhcg present on the apical side of the branchial epithelium facilitates NH3 excretion out of gills. A high concentration of acute ammonia exposure induced elevated Rhbg transcript in the gills of large-scale loaches, while a slight change in Rhbg expression was observed in response to lower ammonia, suggesting that transcriptions of Rhbg genes are activated by a considerably high level of ambient ammonia to eliminate excessive endogenous nitrogen. The Rhag mRNA level in gills of large-scale loaches increased markedly with the prolonging of exposure time from 0 to 36 h of ammonia loading, suggesting Rhag localized in gills may be primarily associated with ammonia handling. During 7-21 days of ammonia exposure, the expression of most Rh glycoproteins-related genes in the gills decreased, indicating that the functional role of Rh glycoproteins is not primarily associated with ammonia defense over a long period (more than 7 days). Although a significant transcript of Rhbg was found in the skin of a large-scale loach, the lack of Rhcg and down-regulation of Rhag may indicate that the skin is not an essential location of ammonia excretion, at least when submerged to high levels of ammonia in the environment. In conclusion, Rh glycoproteins localized in gills as ammonia transporters play a momentous role in ammonia detoxification in this species during acute ammonia loading. However, it does not show a positive function during long-term ammonia exposure. Furthermore, the physiological function of Rh glycoproteins localized in the skin is still unclear and deserves further study.
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Affiliation(s)
- Mei Huang
- College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China
| | - Ze-Hao Shang
- College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China
| | - Meng-Xiao Wu
- College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China
| | - Lin-Jiang Zhang
- College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China
| | - Yun-Long Zhang
- College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China.
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17
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Clifford AM, Wilkie MP, Edwards SL, Tresguerres M, Goss GG. Dining on the dead in the deep: Active NH 4 + excretion via Na + /H + (NH 4 + ) exchange in the highly ammonia tolerant Pacific hagfish, Eptatretus stoutii. Acta Physiol (Oxf) 2022; 236:e13845. [PMID: 35620804 DOI: 10.1111/apha.13845] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 05/22/2022] [Accepted: 05/23/2022] [Indexed: 01/29/2023]
Abstract
AIM Pacific hagfish are exceptionally tolerant to high environmental ammonia (HEA). Here, we elucidated a cellular mechanism that enables hagfish to actively excrete ammonia against steep ammonia gradients expected to be found inside a decomposing whale carcass. METHODS Hagfish were exposed to varying concentrations of HEA in the presence or absence of environmental Na+ , while plasma ammonia levels were tracked. 14 C-methylammonium was used as a proxy for NH4 + to measure efflux in whole animals and in isolated gill pouches; the latter allowed us to assess the effects of amiloride specifically on Na+ /H+ exchangers (NHEs) in gill cells. Western blotting and immunohistochemistry were utilized to evaluate the abundance and sub-cellular localization of Rhesus glycoprotein (Rh) channels in the response to HEA. RESULTS Hagfish actively excreted NH4 + against steep inwardly directed ENH4 + (ΔENH4 + ~ 35 mV) and pNH3 (ΔpNH3 ~ 2000 μtorr) gradients. Active NH4 + excretion and plasma ammonia hypo-regulation were contingent on the presence of environmental Na+ , indicating a Na+ /NH4 + exchange mechanism. Active NH4 + excretion across isolated gill pouches was amiloride-sensitive. Exposure to HEA resulted in decreased abundance of Rh channels in the apical membrane of gill ionocytes. CONCLUSIONS During HEA exposure, hagfish can actively excrete ammonia against a steep concentration gradient using apical NHEs energized by Na+ -K+ -ATPase in gill ionocytes. Additionally, apical Rh channels are removed from the apical membrane, presumably to reduce ammonia loading from the environment. We suggest that this mechanism allows hagfish to maintain tolerable ammonia levels while feeding inside decomposing carrion, allowing them to exploit nutrient-rich food-falls.
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Affiliation(s)
- Alexander M Clifford
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, La Jolla, California, USA.,Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.,Bamfield Marine Sciences Centre, Bamfield, British Columbia, Canada
| | - Michael P Wilkie
- Department of Biology and Laurier Institute for Water Science, Wilfrid Laurier University, Waterloo, Ontario, Canada
| | - Susan L Edwards
- Department of Biological Sciences, Wright State University, Dayton, Ohio, USA
| | - Martin Tresguerres
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, La Jolla, California, USA
| | - Greg G Goss
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.,Bamfield Marine Sciences Centre, Bamfield, British Columbia, Canada
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18
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Aranda-Morales SA, Peña-Marín ES, Jiménez-Martínez LD, Martínez-Burguete T, Martínez-Bautista G, Álvarez-Villagómez CS, De la Rosa-García S, Camarillo-Coop S, Martínez-García R, Guzmán-Villanueva LT, Álvarez-González CA. Expression of ion transport proteins and routine metabolism in juveniles of tropical gar (Atractosteus tropicus) exposed to ammonia. Comp Biochem Physiol C Toxicol Pharmacol 2021; 250:109166. [PMID: 34411697 DOI: 10.1016/j.cbpc.2021.109166] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 07/13/2021] [Accepted: 08/06/2021] [Indexed: 12/14/2022]
Abstract
Tropical gar (Atractosteus tropicus) thrives in aquatic habitats with high levels of total nitrogen (TAN) and unionized ammonia (NH3). However, the tolerance of TAN and NH3, the excretion mechanisms involved, and the effects of these chemicals on routine metabolism are still unknown. Therefore, our objectives were to assess the acute toxicity of TAN and NH3 in A. tropicus juveniles after a 96-h exposure (LC50-96 h) to NH4Cl and after chronic exposure to two concentrations (15% and 30% of LC50-96 h TAN) for 12 days, as well as to evaluate the transcriptional effects associated with Rhesus proteins (rhag, rhbg, rhcg) and ion transporters (NHE, NKA, NKCC, and CFTR) in gills and skin; and to determine the effects of TAN and NH3 on routine metabolism through oxygen consumption (μM g-1 h-1) and gill ventilation frequency (beats min-1). LC50-96 h values were 100.20 ± 11.21 mg/L for TAN and 3.756 ± 0.259 mg/L for NH3. The genes encoding Rhesus proteins and ion transporters in gills and skin showed a differential expression according to TAN concentrations and exposure time. Oxygen consumption on day 12 showed significant differences between treatments with 15% and 30% TAN. Gill ventilation frequency on day 12 was higher in fish exposed to 30% TAN. In conclusion, A. tropicus juveniles are highly tolerant to TAN, showing upregulation of the genes involved in TAN excretion through gills and skin, which affects routine oxygen consumption and energetic cost. These findings are relevant for understanding adaptations in the physiological response of a tropical ancestral air-breathing fish.
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Affiliation(s)
- Sonia A Aranda-Morales
- División Académica de Ciencias Biológicas, Universidad Juárez Autónoma de Tabasco, Carretera Villahermosa-Cárdenas Km 0.5, C.P.86139 Villahermosa, Tabasco, Mexico
| | - Emyr S Peña-Marín
- División Académica de Ciencias Biológicas, Universidad Juárez Autónoma de Tabasco, Carretera Villahermosa-Cárdenas Km 0.5, C.P.86139 Villahermosa, Tabasco, Mexico; Consejo Nacional de Ciencia y Tecnología, Av. Insurgentes Sur 1582, Col. Crédito Constructor, Del. Benito Juárez C.P. 03940, Mexico
| | - Luis D Jiménez-Martínez
- División Académica Multidisciplinaria de Jalpa de Méndez, Universidad Juárez Autónoma de Tabasco, Carretera Nacajuca-Jalpa de Méndez R/a Rivera Alta, C.P. 86200 Jalpa de Méndez, Tabasco, Mexico
| | - Talhia Martínez-Burguete
- División Académica de Ciencias Biológicas, Universidad Juárez Autónoma de Tabasco, Carretera Villahermosa-Cárdenas Km 0.5, C.P.86139 Villahermosa, Tabasco, Mexico
| | - Gil Martínez-Bautista
- División Académica de Ciencias Biológicas, Universidad Juárez Autónoma de Tabasco, Carretera Villahermosa-Cárdenas Km 0.5, C.P.86139 Villahermosa, Tabasco, Mexico
| | - Carina S Álvarez-Villagómez
- División Académica de Ciencias Biológicas, Universidad Juárez Autónoma de Tabasco, Carretera Villahermosa-Cárdenas Km 0.5, C.P.86139 Villahermosa, Tabasco, Mexico
| | - Susana De la Rosa-García
- División Académica de Ciencias Biológicas, Universidad Juárez Autónoma de Tabasco, Carretera Villahermosa-Cárdenas Km 0.5, C.P.86139 Villahermosa, Tabasco, Mexico
| | - Susana Camarillo-Coop
- División Académica de Ciencias Biológicas, Universidad Juárez Autónoma de Tabasco, Carretera Villahermosa-Cárdenas Km 0.5, C.P.86139 Villahermosa, Tabasco, Mexico
| | - Rafael Martínez-García
- División Académica de Ciencias Biológicas, Universidad Juárez Autónoma de Tabasco, Carretera Villahermosa-Cárdenas Km 0.5, C.P.86139 Villahermosa, Tabasco, Mexico
| | - Laura T Guzmán-Villanueva
- Consejo Nacional de Ciencia y Tecnología, Av. Insurgentes Sur 1582, Col. Crédito Constructor, Del. Benito Juárez C.P. 03940, Mexico; Centro de Investigaciones Biológicas del Noroeste S.C., Av. Instituto Politécnico Nacional 195. Col. Playa Palo de Santa Rita Sur, 23096 La Paz, Baja California Sur, Mexico
| | - Carlos A Álvarez-González
- División Académica de Ciencias Biológicas, Universidad Juárez Autónoma de Tabasco, Carretera Villahermosa-Cárdenas Km 0.5, C.P.86139 Villahermosa, Tabasco, Mexico.
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19
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Shang ZH, Huang M, Wu MX, Mi D, You K, Zhang YL. Transcriptomic analyses of the acute aerial and ammonia stress response in the gill and liver of large-scale loach (Paramisgurnus dabryanus). Comp Biochem Physiol C Toxicol Pharmacol 2021; 250:109185. [PMID: 34500090 DOI: 10.1016/j.cbpc.2021.109185] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 08/03/2021] [Accepted: 08/29/2021] [Indexed: 12/13/2022]
Abstract
The large-scale loach (Paramisgurnus dabryanus) is one of the most commercially important cultured species. Ammonia nitrogen accumulation is one of the key issue which limited production and animal health in aquaculture, but few of information is available on the molecular mechanisms of ammonia detoxification. We performed transcriptomic analyses of the gill and liver of large-scale loach subjected to 48 h of aerial and ammonia exposure. We obtained 47,473,424 to 56,791,496 clean reads from the aerial exposure, ammonia exposure and control groups, assembled and clustered a total of 92,658 unigenes with an average length of 909 bp and N50 of 1787 bp. Totals of 489/145 and 424/140 differentially expressed genes (DEGs) were detected in gill/liver of large-scale loach after aerial and ammonia exposure through comparative transcriptome analyses, respectively. In addition, totals of 43 gene ontology (GO) terms and 266 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were identified. After aerial and ammonia exposure, amino acid metabolism pathways in liver of large-scale loach were significantly enriched, suggesting that large-scale loach responded to high exogenous and endogenous ammonia stress by enhancing amino acid metabolism. Besides, the expression of several ammonia transporters (i.e., Rhesus glycoproteins and Aquaporins) in gill of large-scale loach were markedly changed after 48 h of aerial exposure, suggesting that large-scale loach responded to high endogenous ammonia stress by regulating the expression of Rh glycoproteins and Aqps related genes in gill. The results provide valuable information on the molecular mechanism of ammonia detoxification of large-scale loach to endogenous and environmental ammonia loading, will facilitate the molecular assisted breeding of ammonia resistant varieties, and will offer beneficial efforts for establishing an environmental-friendly and sustainable aquaculture industry.
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Affiliation(s)
- Ze-Hao Shang
- College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, China
| | - Mei Huang
- College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, China
| | - Meng-Xiao Wu
- College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, China
| | - Di Mi
- College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, China
| | - Kun You
- College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, China
| | - Yun-Long Zhang
- College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, China.
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20
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Xu Z, Cao J, Qin X, Qiu W, Mei J, Xie J. Toxic Effects on Bioaccumulation, Hematological Parameters, Oxidative Stress, Immune Responses and Tissue Structure in Fish Exposed to Ammonia Nitrogen: A Review. Animals (Basel) 2021; 11:ani11113304. [PMID: 34828036 PMCID: PMC8614401 DOI: 10.3390/ani11113304] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 11/12/2021] [Accepted: 11/15/2021] [Indexed: 01/11/2023] Open
Abstract
Simple Summary Ammonia nitrogen is a common environmental limiting factor in aquaculture, which can accumulate rapidly in water and reach toxic concentrations. In most aquatic environments, fish are vulnerable to the toxic effects of high levels of ammonia nitrogen exposure. It has been found that the toxic effects of ammonia nitrogen on fish are multi-mechanistic. Therefore, the purpose of this review is to explore the various toxic effects of ammonia nitrogen on fish, including oxidative stress, neurotoxicity, tissue damage and immune response. Abstract Ammonia nitrogen is the major oxygen-consuming pollutant in aquatic environments. Exposure to ammonia nitrogen in the aquatic environment can lead to bioaccumulation in fish, and the ammonia nitrogen concentration is the main determinant of accumulation. In most aquatic environments, fish are at the top of the food chain and are most vulnerable to the toxic effects of high levels of ammonia nitrogen exposure. In fish exposed to toxicants, ammonia-induced toxicity is mainly caused by bioaccumulation in certain tissues. Ammonia nitrogen absorbed in the fish enters the circulatory system and affects hematological properties. Ammonia nitrogen also breaks balance in antioxidant capacity and causes oxidative damage. In addition, ammonia nitrogen affects the immune response and causes neurotoxicity because of the physical and chemical toxicity. Thence, the purpose of this review was to investigate various toxic effects of ammonia nitrogen, including oxidative stress, neurotoxicity and immune response.
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Affiliation(s)
- Zhenkun Xu
- College of Food Science and Technology, Shanghai Ocean University, Shanghai 201306, China; (Z.X.); (J.C.); (W.Q.)
- National Experimental Teaching Demonstration Center for Food Science and Engineering, Shanghai Ocean University, Shanghai 201306, China
- Shanghai Engineering Research Center of Aquatic Product Processing and Preservation, Shanghai 201306, China
- Shanghai Professional Technology Service Platform on Cold Chain Equipment Performance and Energy Saving Evaluation, Shanghai 201306, China
| | - Jie Cao
- College of Food Science and Technology, Shanghai Ocean University, Shanghai 201306, China; (Z.X.); (J.C.); (W.Q.)
- National Experimental Teaching Demonstration Center for Food Science and Engineering, Shanghai Ocean University, Shanghai 201306, China
- Shanghai Engineering Research Center of Aquatic Product Processing and Preservation, Shanghai 201306, China
- Shanghai Professional Technology Service Platform on Cold Chain Equipment Performance and Energy Saving Evaluation, Shanghai 201306, China
| | - Xiaoming Qin
- College of Food Science and Technology, Guangdong Ocean University, Zhanjiang 524088, China;
| | - Weiqiang Qiu
- College of Food Science and Technology, Shanghai Ocean University, Shanghai 201306, China; (Z.X.); (J.C.); (W.Q.)
- National Experimental Teaching Demonstration Center for Food Science and Engineering, Shanghai Ocean University, Shanghai 201306, China
- Shanghai Engineering Research Center of Aquatic Product Processing and Preservation, Shanghai 201306, China
- Shanghai Professional Technology Service Platform on Cold Chain Equipment Performance and Energy Saving Evaluation, Shanghai 201306, China
| | - Jun Mei
- College of Food Science and Technology, Shanghai Ocean University, Shanghai 201306, China; (Z.X.); (J.C.); (W.Q.)
- National Experimental Teaching Demonstration Center for Food Science and Engineering, Shanghai Ocean University, Shanghai 201306, China
- Shanghai Engineering Research Center of Aquatic Product Processing and Preservation, Shanghai 201306, China
- Shanghai Professional Technology Service Platform on Cold Chain Equipment Performance and Energy Saving Evaluation, Shanghai 201306, China
- Correspondence: (J.M.); (J.X.); Tel.: +86-21-61900349 (J.M.); +86-21-61900351 (J.X.)
| | - Jing Xie
- College of Food Science and Technology, Shanghai Ocean University, Shanghai 201306, China; (Z.X.); (J.C.); (W.Q.)
- National Experimental Teaching Demonstration Center for Food Science and Engineering, Shanghai Ocean University, Shanghai 201306, China
- Shanghai Engineering Research Center of Aquatic Product Processing and Preservation, Shanghai 201306, China
- Shanghai Professional Technology Service Platform on Cold Chain Equipment Performance and Energy Saving Evaluation, Shanghai 201306, China
- Correspondence: (J.M.); (J.X.); Tel.: +86-21-61900349 (J.M.); +86-21-61900351 (J.X.)
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21
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Wang Y, Pasparakis C, Grosell M. Role of the cardiovascular system in ammonia excretion in early life stages of zebrafish ( Danio rerio). Am J Physiol Regul Integr Comp Physiol 2021; 321:R377-R384. [PMID: 34318705 DOI: 10.1152/ajpregu.00284.2020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 07/20/2021] [Indexed: 11/22/2022]
Abstract
The purpose of this study was to investigate if the cardiovascular system is important for ammonia excretion in the early life stages of zebrafish. Morpholino knockdowns of cardiac troponin T (TNNT2) or vascular endothelial growth factor A (VEGFA) provided morphants with nonfunctional circulation. At the embryonic stage [30-36 h postfertilization (hpf)], ammonia excretion was not constrained by a lack of cardiovascular function. At 2 days postfertilization (dpf) and 4 dpf, morpholino knockdowns of TNNT2 or VEGFA significantly reduced ammonia excretion in all morphants. Expression of rhag, rhbg, and rhcgb showed no significant changes but the mRNA levels of the urea transporter (ut) were upregulated in the 4 dpf morphants. Taken together, rhag, rhbg, rhcgb, and ut gene expression and an unchanged tissue ammonia concentration but an increased tissue urea concentration, suggest that impaired ammonia excretion led to increased urea synthesis. However, in larvae anesthetized with tricaine or clove oil, ammonia excretion was not reduced in the 4 dpf morphants compared with controls. Furthermore, oxygen consumption was reduced in morphants regardless of anesthesia. These results suggest that cardiovascular function is not directly involved in ammonia excretion, but rather reduced activity and external convection may explain reduced ammonia excretion and compensatory urea accumulation in morphants with reduced cardiovascular function.
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Affiliation(s)
- Y Wang
- Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, Florida
| | - C Pasparakis
- Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, Florida
| | - M Grosell
- Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, Florida
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22
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Morris C, Val AL, Brauner CJ, Wood CM. The physiology of fish in acidic waters rich in dissolved organic carbon, with specific reference to the Amazon basin: Ionoregulation, acid-base regulation, ammonia excretion, and metal toxicity. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2021; 335:843-863. [PMID: 33970558 DOI: 10.1002/jez.2468] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 03/26/2021] [Accepted: 03/31/2021] [Indexed: 11/06/2022]
Abstract
Although blackwaters, named for their rich content of dissolved organic carbon (DOC), are often very poor in ions and very acidic, they support great fish biodiversity. Indeed, about 8% of all freshwater fish species live in the blackwaters of the Rio Negro watershed in the Amazon basin. We review how native fish survive these harsh conditions that would kill most freshwater fish, with a particular focus on the role of DOC, a water quality parameter that has been relatively understudied. DOC, which is functionally defined by its ability to pass through a 0.45-µm filter, comprises a diverse range of compounds formed by the breakdown of organic matter and is quantified by its carbon component that is approximately 50% by mass. Adaptations of fish to acidic blackwaters include minimal acid-base disturbances associated with a unique, largely unknown, high-affinity Na+ uptake system that is resistant to inhibition by low pH in members of the Characiformes, and very tight regulation of Na+ efflux at low pH in the Cichliformes. Allochthonous (terrigenous) DOC, which predominates in blackwaters, consists of larger, more highly colored, reactive molecules than autochthonous DOC. The dissociation of protons from allochthonous components such as humic and fulvic acids is largely responsible for the acidity of these blackwaters, yet at the same time, these components may help protect organisms against the damaging effects of low water pH. DOC lowers the transepithelial potential (TEP), mitigates the inhibition of Na+ uptake and ammonia excretion, and protects against the elevation of diffusive Na+ loss in fish exposed to acidic waters. It also reduces the gill binding and toxicity of metals. At least in part, these actions reflect direct biological effects of DOC on the gills that are beneficial to ionoregulation. After chronic exposure to DOC, some of these protective effects persist even in the absence of DOC. Two characteristics of allochthonous DOC, the specific absorbance coefficient at 340 nm (determined optically) and the PBI (determined by titration), are indicative of both the biological effectiveness of DOC and the ability to protect against metal toxicity. Future research needs are highlighted, including a greater mechanistic understanding of the actions of DOCs on gill ionoregulatory function, morphology, TEP, and metal toxicity. These should be investigated in a wider range of native fish Orders that inhabit one of the world's greatest biodiversity hotspots for freshwater fishes.
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Affiliation(s)
- Carolyn Morris
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Adalberto L Val
- Laboratory of Ecophysiology and Molecular Evolution, Brazilian National Institute for Research of the Amazon, Manaus, Brazil
| | - Colin J Brauner
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Chris M Wood
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Biology, McMaster University, Hamilton, Ontario, Canada.,Laboratory of Ecophysiology and Molecular Evolution, Brazilian National Institute for Research of the Amazon, Manaus, Brazil
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23
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Zimmer AM, Goss GG, Glover CN. Reductionist approaches to the study of ionoregulation in fishes. Comp Biochem Physiol B Biochem Mol Biol 2021; 255:110597. [PMID: 33781928 DOI: 10.1016/j.cbpb.2021.110597] [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: 01/05/2021] [Revised: 03/15/2021] [Accepted: 03/22/2021] [Indexed: 10/21/2022]
Abstract
The mechanisms underlying ionoregulation in fishes have been studied for nearly a century, and reductionist methods have been applied at all levels of biological organization in this field of research. The complex nature of ionoregulatory systems in fishes makes them ideally suited to reductionist methods and our collective understanding has been dramatically shaped by their use. This review provides an overview of the broad suite of techniques used to elucidate ionoregulatory mechanisms in fishes, from the whole-animal level down to the gene, discussing some of the advantages and disadvantages of these methods. We provide a roadmap for understanding and appreciating the work that has formed the current models of organismal, endocrine, cellular, molecular, and genetic regulation of ion balance in fishes and highlight the contribution that reductionist techniques have made to some of the fundamental leaps forward in the field throughout its history.
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Affiliation(s)
- Alex M Zimmer
- Department of Biological Sciences, CW 405, Biological Sciences Bldg., University of Alberta, Edmonton, AB T6G 2E9, Canada.
| | - Greg G Goss
- Department of Biological Sciences, CW 405, Biological Sciences Bldg., University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - Chris N Glover
- Department of Biological Sciences, CW 405, Biological Sciences Bldg., University of Alberta, Edmonton, AB T6G 2E9, Canada; Faculty of Science and Technology and Athabasca River Basin Research Institute, Athabasca University, Athabasca, AB T9S 3A3, Canada
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24
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Thalib YA, Razali RS, Mohamad S, Zainuddin R'A, Rahmah S, Ghaffar MA, Nhan HT, Liew HJ. Environmental changes affecting physiological responses and growth of hybrid grouper - The interactive impact of low pH and temperature. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 271:116375. [PMID: 33422747 DOI: 10.1016/j.envpol.2020.116375] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 12/02/2020] [Accepted: 12/20/2020] [Indexed: 06/12/2023]
Abstract
Rising of temperature in conjunction with acidification due to the anthropogenic climates has tremendously affected all aquatic life. Small changes in the surrounding environment could lead to physiological constraint in the individual. Therefore, this study was designed to investigate the effects of warm water temperature (32 °C) and low pH (pH 6) on physiological responses and growth of hybrid grouper (Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂) juveniles for 25 days. Growth performance was significantly affected under warm water temperature and low-pH conditions. Surprisingly, the positive effect on growth was observed under the interactive effects of warm water and low pH exposure. Hybrid grouper exposed to the interactive stressor of warm temperature and low pH exhibited higher living cost, where HSI content was greatly depleted to about 2.3-folds than in normal circumstances. Overall, challenge to warm temperature and low pH induced protein mobilization as an energy source followed by glycogen and lipid to support basal metabolic needs.
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Affiliation(s)
- Yusnita A Thalib
- Institute of Tropical Aquaculture and Fisheries, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia
| | - Ros Suhaida Razali
- Institute of Tropical Aquaculture and Fisheries, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia
| | - Suhaini Mohamad
- Institute of Tropical Aquaculture and Fisheries, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia
| | - Rabi'atul 'Adawiyyah Zainuddin
- Institute of Tropical Aquaculture and Fisheries, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia
| | - Sharifah Rahmah
- Institute of Tropical Aquaculture and Fisheries, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia; Faculty of Fisheries and Food Science, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia
| | - Mazlan Abd Ghaffar
- Institute of Tropical Aquaculture and Fisheries, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia; Faculty of Science and Marine Environment, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia; Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia
| | - Hua Thai Nhan
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Viet Nam
| | - Hon Jung Liew
- Institute of Tropical Aquaculture and Fisheries, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia; Faculty of Fisheries and Food Science, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia; Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, 232 Hesong St, Daoli District, Harbin, Heilongjiang, 150070, China.
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25
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Egnew N, Renukdas N, Romano N, Kelly AM, Lohakare J, Bishop WM, Lochmann RT, Sinha AK. Physio-biochemical, metabolic nitrogen excretion and ion-regulatory assessment in largemouth bass (Micropterus salmoides) following exposure to high environmental iron. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2021; 208:111526. [PMID: 33099141 DOI: 10.1016/j.ecoenv.2020.111526] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 10/11/2020] [Accepted: 10/14/2020] [Indexed: 05/20/2023]
Abstract
Iron overload is a significant water quality issue in many parts of the world. Therefore, we evaluated the potential toxic effects of waterborne elevated iron on largemouth bass (Micropterus salmoides), a highly valued sport and aquaculture fish species. First, a 96 h-LC50 toxicity assay was performed to understand the tolerance limit of this species to iron; and was determined to be 22.07 mg/L (as Fe3+). Thereafter, to get a better insight on the fish survival during long-term exposure to high environmental iron (HEI) (5.52 mg/L, 25% of the determined 96 h-LC50 value), a suite of physio-biochemical, nitrogenous metabolic and ion-regulatory compensatory responses were examined at 7, 14, 21 and 28 days. Results showed that oxygen consumption dropped significantly at 21 and 28 days of HEI exposure. Ammonia excretion rate (Jamm) was significantly inhibited from day 14 and remained suppressed until the last exposure period. The transcript concentration of Rhesus glycoproteins Rhcg2 declined; likely diminishing ammonia efflux out of gills. These changes were also reflected by a parallel increment in plasma ammonia levels. Under HEI exposure, ion-balance was negatively affected, manifested by reduced plasma [Na+] and parallel inhibition in branchial Na+/K+-ATPase activity. Muscle water content was elevated in HEI-exposed fish, signifying an osmo-regulatory compromise. HEI exposure also increased iron burden in plasma and gills. The iron accumulation pattern in gills was significantly correlated with a suppression of Jamm, branchial Rhcg2 expression and Na+/K+-ATPase activity. There was also a decline in the glycogen, protein and lipid reserves in the hepatic tissue from 14 days, 28 days and 21 days, respectively. Overall, we conclude that sub-lethal chronic iron exposure can impair normal physio-biochemical and ion-regulatory functions in largemouth bass. Moreover, this data set can be applied in assessing the environmental risk posed by a waterborne iron overload on aquatic life.
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Affiliation(s)
- Nathan Egnew
- Department of Aquaculture and Fisheries, University of Arkansas at Pine Bluff, 1200 North University Drive, Pine Bluff, AR 71601, USA
| | - Nilima Renukdas
- Department of Aquaculture and Fisheries, University of Arkansas at Pine Bluff, 1200 North University Drive, Pine Bluff, AR 71601, USA
| | - Nicholas Romano
- Department of Aquaculture and Fisheries, University of Arkansas at Pine Bluff, 1200 North University Drive, Pine Bluff, AR 71601, USA
| | - Anita M Kelly
- Department of Aquaculture and Fisheries, University of Arkansas at Pine Bluff, 1200 North University Drive, Pine Bluff, AR 71601, USA; Alabama Fish Farming Center, Auburn University, Greensboro, AL 36744, USA
| | - Jayant Lohakare
- Department of Agriculture-Animal Science, University of Arkansas at Pine Bluff, 1200 North University Drive, Pine Bluff, AR 71601, USA
| | - West M Bishop
- SePRO Research and Technology Campus, 16013 Watson Seed Farm Rd., Whitakers, NC 27891, USA
| | - Rebecca T Lochmann
- Department of Aquaculture and Fisheries, University of Arkansas at Pine Bluff, 1200 North University Drive, Pine Bluff, AR 71601, USA
| | - Amit Kumar Sinha
- Department of Aquaculture and Fisheries, University of Arkansas at Pine Bluff, 1200 North University Drive, Pine Bluff, AR 71601, USA.
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26
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Eom J, Wood CM. Brain and gills as internal and external ammonia sensing organs for ventilatory control in rainbow trout, Oncorhynchus mykiss. Comp Biochem Physiol A Mol Integr Physiol 2021; 254:110896. [PMID: 33444774 DOI: 10.1016/j.cbpa.2021.110896] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 01/05/2021] [Accepted: 01/07/2021] [Indexed: 11/25/2022]
Abstract
Ammonia is both a respiratory gas and a toxicant in teleost fish. Hyperventilation is a well-known response to elevations of both external and internal ammonia levels. Branchial neuroepithelial cells (NECs) are thought to serve as internal sensors of plasma ammonia (peripheral chemoreceptors), but little is known about other possible ammonia-sensors. Here, we investigated whether trout possess external sensors and/or internal central chemoreceptors for ammonia. For external sensors, we analyzed the time course of ventilatory changes at the start of exposure to high environmental ammonia (HEA, 1 mM). Hyperventilation developed gradually over 20 min, suggesting that it was a response to internal ammonia elevation. We also directly perfused ammonia solutions (0.01-1 mM) to the external surfaces of the first gill arches. Immediate hypoventilation occurred. For central chemoreceptors, we injected ammonia solutions (0.5-1.0 mM) directly onto the surface of the hindbrain of anesthetized trout. Immediate hyperventilation occurred. This is the first evidence of central chemoreception in teleost fish. We conclude that trout possess both external ammonia sensors, and dual internal ammonia sensors (perhaps for redundancy), but their roles differ. External sensors cause short term hypoventilation, which would help limit toxic waterborne ammonia uptake. When fish cannot avoid HEA, the diffusion of waterborne ammonia into the blood will stimulate both peripheral (NECs) and central (brain) chemoreceptors, resulting in hyperventilation. This hyperventilation will be beneficial in increasing ammonia excretion via the Rh metabolon system in the gills not only after HEA exposure, but also after endogenous ammonia loading from feeding or exercise.
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Affiliation(s)
- Junho Eom
- Department of Zoology, University of British Columbia, Vancouver, BC V6T1Z4, Canada.
| | - Chris M Wood
- Department of Zoology, University of British Columbia, Vancouver, BC V6T1Z4, Canada.
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27
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Porteus C, Kumai Y, Abdallah SJ, Yew HM, Kwong RW, Pan Y, Milsom WK, Perry SF. Respiratory responses to external ammonia in zebrafish (Danio rerio). Comp Biochem Physiol A Mol Integr Physiol 2021; 251:110822. [DOI: 10.1016/j.cbpa.2020.110822] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 09/10/2020] [Accepted: 10/09/2020] [Indexed: 01/03/2023]
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28
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Tunnah L, Robertson CE, Turko AJ, Wright PA. Acclimation to prolonged aquatic hypercarbia or air enhances hemoglobin‑oxygen affinity in an amphibious fish. Comp Biochem Physiol A Mol Integr Physiol 2020; 252:110848. [PMID: 33217558 DOI: 10.1016/j.cbpa.2020.110848] [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: 07/31/2020] [Revised: 11/12/2020] [Accepted: 11/12/2020] [Indexed: 10/23/2022]
Abstract
When the amphibious mangrove rivulus (Kryptolebias marmoratus) leaves water for extended periods, hemoglobin-O2 binding affinity increases. We tested the hypothesis that the change in affinity was a consequence of hemoglobin isoform switching driven by exposure to environments associated with increased internal CO2 levels. We exposed K. marmoratus to either water (control, pH 8.1), air, aquatic hypercarbia (5.1 kPa CO2, pH 6.6-6.8), or aquatic acid (isocarbic control, pH 6.6-6.8), for 7 days, and measured hemoglobin-O2 affinity spectrophotometrically. We found that mangrove rivulus compensated for elevated CO2 and aquatic acid exposure by shifting hemoglobin-O2 affinity back to aquatic (control) levels when measured at an ecologically-relevant high CO2 level that would be experienced in vivo. Using proteomics, we found that the hemoglobin subunits present in the blood did not change between treatments, but air and aquatic acid exposure altered the abundance of cathodic hemoglobin subunits. We therefore conclude that hemoglobin isoform switching is not a primary strategy used by mangrove rivulus to adjust P50 under these conditions. Abundances of other RBC proteins also differed between treatment groups relative to control fish (e.g. Rhesus protein type A, band 3 anion exchanger). Overall, our data indicate that both aquatic hypercarbia and aquatic acidosis create similar changes in hemoglobin-O2 affinity as air exposure. However, the protein-level consequences differ between these groups, indicating that the red blood cell response of mangrove rivulus can be modulated depending on the environmental cue received.
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Affiliation(s)
- Louise Tunnah
- Department of Integrative Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada.
| | - Cayleih E Robertson
- Department of Integrative Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada; Department of Biology, McMaster University, Hamilton, Ontario L8S 4K1, Canada.
| | - Andy J Turko
- Department of Integrative Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada; Department of Biology, McMaster University, Hamilton, Ontario L8S 4K1, Canada; Great Lakes Institute for Environmental Research, University of Windsor, Windsor, ON N9B 3P4, Canada
| | - Patricia A Wright
- Department of Integrative Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada.
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Sunga J, Wilson JM, Wilkie MP. Functional re-organization of the gills of metamorphosing sea lamprey (Petromyzon marinus): preparation for a blood diet and the freshwater to seawater transition. J Comp Physiol B 2020; 190:701-715. [PMID: 32852575 DOI: 10.1007/s00360-020-01305-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 05/31/2020] [Accepted: 06/18/2020] [Indexed: 11/28/2022]
Abstract
Sea lamprey (Petromyzon marinus) begin life as filter-feeding larvae (ammocoetes) before undergoing a complex metamorphosis into parasitic juveniles, which migrate to the sea where they feed on the blood of large-bodied fishes. The greater protein intake during this phase results in marked increases in the production of nitrogenous wastes (N-waste), which are excreted primarily via the gills. However, it is unknown how gill structure and function change during metamorphosis and how it is related to modes of ammonia excretion, nor do we have a good understanding of how the sea lamprey's transition from fresh water (FW) to sea water (SW) affects patterns and mechanisms of N-waste excretion in relation to ionoregulation. Using immunohistochemistry, we related changes in the gill structure of larval, metamorphosing, and juvenile sea lampreys to their patterns of ammonia excretion (Jamm) and urea excretion (Jurea) in FW, and following FW to artificial seawater (ASW) transfer. Rates of Jamm and Jurea were low in larval sea lamprey and increased in feeding juvenile, parasitic sea lamprey. In freshwater-dwelling ammocoetes, immunohistochemical analysis revealed that Rhesus glycoprotein C-like protein (Rhcg-like) was diffusely distributed on the lamellar epithelium, but following metamorphosis, Rhcg-like protein was restricted to SW mitochondrion-rich cells (MRCs; ionocytes) between the gill lamellae. Notably, these interlamellar Rhcg-like proteins co-localized with Na+/K+-ATPase (NKA), which increased in expression and activity by almost tenfold during metamorphosis. The distribution of V-type H+-ATPase (V-ATPase) on the lamellae decreased following metamorphosis, indicating it may have a more important role in acid-base regulation and Na+ uptake in FW, compared to SW. We conclude that the re-organization of the sea lamprey gill during metamorphosis not only plays a critical role in allowing them to cope with greater salinity following the FW-SW transition, but that it simultaneously reflects fundamental changes in methods used to excrete ammonia.
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Affiliation(s)
- Julia Sunga
- Department of Biology and Laurier Institute for Water Science, Wilfrid Laurier University, Waterloo, ON, N2L 3C5, Canada
| | - Jonathan M Wilson
- Department of Biology and Laurier Institute for Water Science, Wilfrid Laurier University, Waterloo, ON, N2L 3C5, Canada
| | - Michael P Wilkie
- Department of Biology and Laurier Institute for Water Science, Wilfrid Laurier University, Waterloo, ON, N2L 3C5, Canada.
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Skeletal Muscle and the Effects of Ammonia Toxicity in Fish, Mammalian, and Avian Species: A Comparative Review Based on Molecular Research. Int J Mol Sci 2020; 21:ijms21134641. [PMID: 32629824 PMCID: PMC7370143 DOI: 10.3390/ijms21134641] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 06/26/2020] [Accepted: 06/29/2020] [Indexed: 12/22/2022] Open
Abstract
Typically, mammalian and avian models have been used to examine the effects of ammonia on skeletal muscle. Hyperammonemia causes sarcopenia or muscle wasting, in mammals and has been linked to sarcopenia in liver disease patients. Avian models of skeletal muscle have responded positively to hyperammonemia, differing from the mammalian response. Fish skeletal muscle has not been examined as extensively as mammalian and avian muscle. Fish skeletal muscle shares similarities with avian and mammalian muscle but has notable differences in growth, fiber distribution, and response to the environment. The wide array of body sizes and locomotion needs of fish also leads to greater diversity in muscle fiber distribution and growth between different fish species. The response of fish muscle to high levels of ammonia is important for aquaculture and quality food production but has not been extensively studied to date. Understanding the differences between fish, mammalian and avian species’ myogenic response to hyperammonemia could lead to new therapies for muscle wasting due to a greater understanding of the mechanisms behind skeletal muscle regulation and how ammonia effects these mechanisms. This paper provides an overview of fish skeletal muscle and ammonia excretion and toxicity in fish, as well as a comparison to avian and mammalian species.
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Tresguerres M, Clifford AM, Harter TS, Roa JN, Thies AB, Yee DP, Brauner CJ. Evolutionary links between intra- and extracellular acid-base regulation in fish and other aquatic animals. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2020; 333:449-465. [PMID: 32458594 DOI: 10.1002/jez.2367] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 03/10/2020] [Accepted: 05/06/2020] [Indexed: 12/17/2022]
Abstract
The acid-base relevant molecules carbon dioxide (CO2 ), protons (H+ ), and bicarbonate (HCO3 - ) are substrates and end products of some of the most essential physiological functions including aerobic and anaerobic respiration, ATP hydrolysis, photosynthesis, and calcification. The structure and function of many enzymes and other macromolecules are highly sensitive to changes in pH, and thus maintaining acid-base homeostasis in the face of metabolic and environmental disturbances is essential for proper cellular function. On the other hand, CO2 , H+ , and HCO3 - have regulatory effects on various proteins and processes, both directly through allosteric modulation and indirectly through signal transduction pathways. Life in aquatic environments presents organisms with distinct acid-base challenges that are not found in terrestrial environments. These include a relatively high CO2 relative to O2 solubility that prevents internal CO2 /HCO3 - accumulation to buffer pH, a lower O2 content that may favor anaerobic metabolism, and variable environmental CO2 , pH and O2 levels that require dynamic adjustments in acid-base homeostatic mechanisms. Additionally, some aquatic animals purposely create acidic or alkaline microenvironments that drive specialized physiological functions. For example, acidifying mechanisms can enhance O2 delivery by red blood cells, lead to ammonia trapping for excretion or buoyancy purposes, or lead to CO2 accumulation to promote photosynthesis by endosymbiotic algae. On the other hand, alkalinizing mechanisms can serve to promote calcium carbonate skeletal formation. This nonexhaustive review summarizes some of the distinct acid-base homeostatic mechanisms that have evolved in aquatic organisms to meet the particular challenges of this environment.
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Affiliation(s)
- Martin Tresguerres
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, California
| | - Alexander M Clifford
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, California
| | - Till S Harter
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, California
| | - Jinae N Roa
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, California
| | - Angus B Thies
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, California
| | - Daniel P Yee
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, California
| | - Colin J Brauner
- Department of Zoology, University of British Columbia, Vancouver, Canada
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Zimmer AM, Perry SF. The Rhesus glycoprotein Rhcgb is expendable for ammonia excretion and Na + uptake in zebrafish (Danio rerio). Comp Biochem Physiol A Mol Integr Physiol 2020; 247:110722. [PMID: 32437959 DOI: 10.1016/j.cbpa.2020.110722] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 05/01/2020] [Accepted: 05/01/2020] [Indexed: 11/27/2022]
Abstract
In zebrafish (Danio rerio), the ammonia-transporting Rhesus glycoprotein Rhcgb is implicated in mechanisms of ammonia excretion and Na+ uptake. In particular, Rhcgb is thought to play an important role in maintaining ammonia excretion in response to alkaline conditions and high external ammonia (HEA) exposure, in addition to facilitating Na+ uptake via a functional metabolon with the Na+/H+-exchanger Nhe3b, specifically under low Na+ conditions. In the present study, we hypothesized that CRISPR/Cas9 knockout of rhcgb would reduce ammonia excretion and Na+ uptake capacity, particularly under the conditions listed above that have elicited increases in Rhcgb-mediated ammonia excretion and/or Na+ uptake. Contrary to this hypothesis, however, larval and juvenile rhcgb knockout (KO) mutants showed no reductions in ammonia excretion or Na+ uptake under any of the conditions tested in our study. In fact, under control conditions, rhcgb KO mutants generally displayed an increase in ammonia excretion, potentially due to increased transcript abundance of another rh gene, rhbg. Under alkaline conditions, rhcgb KO mutants were also able to maintain ammonia excretion, similar to wild-type fish, and stimulation of ammonia excretion after HEA exposure also was not affected by rhcgb KO. Surprisingly, ammonia excretion and Na+ uptake were unaffected by rhcgb or nhe3b KO in juvenile zebrafish acclimated to normal (800 μmol/L) or low (10 μmol/L) Na+ conditions. These results demonstrate that Rhcgb is expendable for ammonia excretion and Na+ uptake in zebrafish, highlighting the plasticity and flexibility of these physiological systems in this species.
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Affiliation(s)
- Alex M Zimmer
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada; 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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Eom J, Fehsenfeld S, Wood CM. Is ammonia excretion affected by gill ventilation in the rainbow trout Oncorhynchus mykiss? Respir Physiol Neurobiol 2020; 275:103385. [DOI: 10.1016/j.resp.2020.103385] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 12/09/2019] [Accepted: 01/08/2020] [Indexed: 02/08/2023]
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Bernard B, Leguen I, Mandiki SNM, Cornet V, Redivo B, Kestemont P. Impact of temperature shift on gill physiology during smoltification of Atlantic salmon smolts (Salmo salar L.). Comp Biochem Physiol A Mol Integr Physiol 2020; 244:110685. [PMID: 32165323 DOI: 10.1016/j.cbpa.2020.110685] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 02/20/2020] [Accepted: 02/25/2020] [Indexed: 11/15/2022]
Abstract
Exposure to a temperature increase may disrupt smoltification and delay or stop the downstream migration of smolts. Thermal regimes are often different between a river and its tributaries, but the effects of a relative temperature shift are not well described. We used expression of smoltification genes coupled with gill Na+/K+-ATPase activity (NKA) and plasma cortisol and growth hormone (GH) levels to investigate the impact of a 5 °C difference between tributary and river on salmon juveniles. Responses to a temperature challenge were examined at four time points during the smoltification period, with juveniles reared under three regimes including control, early and late temperature increase. The temperature shifts reduced gill NKA, plasma GH and cortisol levels which indicate hypo-osmoregulation impairment and may reduce the survival of smolts. Out of the 22 genes examined, the expression of six genes was influenced by the temperature treatments, while changes in further eleven genes were influenced by the date of sampling. Genes usually known to be upregulated during smoltification were downregulated after the temperature increase, notably nkaα1b, nkcc1a and igf1r. Upregulation of some genes involved in the hormonal regulation and acid-base equilibrium in early June may indicate a switch towards desmoltification. This study gives further insights about the impact of temperature increase on the molecular processes underlying smoltification and possible responses to human-related water temperature increase. The data also suggest dual roles in the smoltification and desmoltification for GH and IGF1 and points to the implication of genes in the smoltification process, that have previously been unstudied (nbc) or with little data available (igf2).
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Affiliation(s)
- Benoît Bernard
- University of Namur, Institute of Life, Earth and Environment (ILEE), Research Unit in Environmental and Evolutionary Biology (URBE), Rue de Bruxelles, 61, B-5000 Namur, Belgium..
| | - Isabelle Leguen
- Fish Physiology and Genomics Institute, Campus of Beaulieu, Building 16A, 35042 Rennes Cedex, France.
| | - Syaghalirwa N M Mandiki
- University of Namur, Institute of Life, Earth and Environment (ILEE), Research Unit in Environmental and Evolutionary Biology (URBE), Rue de Bruxelles, 61, B-5000 Namur, Belgium..
| | - Valerie Cornet
- University of Namur, Institute of Life, Earth and Environment (ILEE), Research Unit in Environmental and Evolutionary Biology (URBE), Rue de Bruxelles, 61, B-5000 Namur, Belgium..
| | - Baptiste Redivo
- University of Namur, Institute of Life, Earth and Environment (ILEE), Research Unit in Environmental and Evolutionary Biology (URBE), Rue de Bruxelles, 61, B-5000 Namur, Belgium..
| | - Patrick Kestemont
- University of Namur, Institute of Life, Earth and Environment (ILEE), Research Unit in Environmental and Evolutionary Biology (URBE), Rue de Bruxelles, 61, B-5000 Namur, Belgium..
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Malakpour Kolbadinezhad S, Coimbra J, Wilson JM. Is the dendritic organ of the striped eel catfish Plotosus lineatus an ammonia excretory organ? Comp Biochem Physiol A Mol Integr Physiol 2019; 241:110640. [PMID: 31870932 DOI: 10.1016/j.cbpa.2019.110640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 12/13/2019] [Accepted: 12/16/2019] [Indexed: 11/24/2022]
Abstract
The dendritic organ (DO) is a salt secretory organ in the Plotosidae marine catfishes. The potential role of the DO in ammonia excretion was investigated by examining the effects of salinity [brackishwater (BW 3‰), seawater (SW 34‰) and hypersaline water (HSW 60‰)] acclimation and DO ligation on ammonia excretion and ammonia transporter expression by immunohistochemistry (IHC), immunoblotting (IB) and qPCR. Ammonia flux rates (JAmm) were significantly lower in BW compared to SW and HSW. DO ligation resulted in a significantly lower JAmm in SW but not BW fish. IHC demonstrated apical and basolateral localization of Rhesus-associated glycoprotein (Rhag-like) and Rhbg-like proteins, respectively, in parenchymal cells of the DO acini. In the gills, which are the primary site of ammonia excretion in teleost fishes, IHC showed an apical localization of Rhag-like protein in some Na+/K+-ATPase (NKA) immunoreactive (IR) cells limited to a few interlamellar regions of the filament and, in both apical and basolateral membranes of pillar cells irrespective of treatment group. In gills, the distribution of NKA-IR cells showed no salinity and/or ligation dependency. IB of Rhag and Rhbg-like proteins was found only in the gills and expression levels did not change with salinity but ligation in BW decreased Rhbg-like levels. Although Rhcg was not detected with heterologous antibodies, rhcg1 mRNA expression was detected in both gills and DO. HSW was associated with the lowest expression in DO and ligations in SW and BW were without effect on branchial expression levels. Taken together these results indicate the DO potentially has a physiological role in ammonia excretion under SW conditions.
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Affiliation(s)
- Salman Malakpour Kolbadinezhad
- Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR/CIMAR), Universidade do Porto, Porto, Portugal; Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal; Coldwater Fisheries Research Center (CFRC), Iranian Fisheries Sciences Research Institute (IFSRI), Agricultural Research, Education and Extension Organization, Tonekabon, Iran.
| | - João Coimbra
- Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR/CIMAR), Universidade do Porto, Porto, Portugal; Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal.
| | - Jonathan M Wilson
- Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR/CIMAR), Universidade do Porto, Porto, Portugal; Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal; Department of Biology, Wilfrid Laurier University, Waterloo, Canada.
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36
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Wang Y, Pasparakis C, Stieglitz JD, Benetti DD, Grosell M. The effects of Deepwater Horizon crude oil on ammonia and urea handling in mahi-mahi (Coryphaena hippurus) early life stages. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2019; 216:105294. [PMID: 31585273 DOI: 10.1016/j.aquatox.2019.105294] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 09/05/2019] [Accepted: 09/05/2019] [Indexed: 06/10/2023]
Abstract
Many ecologically important fishes, including mahi-mahi (Coryphaena hippurus), and their offspring were directly exposed to crude oil following the Deepwater Horizon (DWH) oil spill. Early life stage fish are especially vulnerable to the toxicity of crude oil-derived polycyclic aromatic hydrocarbons (PAHs). In teleosts, yolk sac proteins are the main energy source during development and are usually catabolized into ammonia or urea among other byproducts. Although excretion of these waste products is sensitive to oil exposure, we know little about the underlying mechanisms of this process. In this study, we examined the effects of crude oil on ammonia and urea handling in the early life stages of mahi. Mahi embryos exposed to 30-32 μg L-1 ∑PAH exhibited increased urea excretion rates and greater accumulation of urea in the tissues before hatch suggesting that ammonia, which is highly toxic, was converted into less-toxic urea. Oil-exposed embryos (6.3-32 μg L-1 ∑PAH) displayed significantly increased tissue ammonia levels at 42 hpf and upregulated mRNA levels of ammonia transporters (Rhag, Rhbg and Rhcg1) from 30 to 54 hpf. However, despite increased accumulation and higher expression of ammonia transporters, the larvae exposed to higher ∑PAH (30 μg L-1 ∑PAH) showed reduced ammonia excretion rates after hatch. Together, the increased production of nitrogenous waste reinforces previous work that increased energy demand in oil-exposed embryos is fueled, at least in part, by protein metabolism and that urea synthesis plays a role in ammonia detoxification in oil-exposed mahi embryos. To our knowledge, this study is the first to combine physiological and molecular approaches to assess the impact of crude-oil on both nitrogenous waste excretion and accumulation in the early life stages of any teleosts.
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Affiliation(s)
- Y Wang
- Department of Marine Biology and Ecology, RSMAS, University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149, United States.
| | - C Pasparakis
- Department of Marine Biology and Ecology, RSMAS, University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149, United States
| | - J D Stieglitz
- Department of Marine Ecosystems and Society, RSMAS, University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149, United States
| | - D D Benetti
- Department of Marine Ecosystems and Society, RSMAS, University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149, United States
| | - M Grosell
- Department of Marine Biology and Ecology, RSMAS, University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149, United States
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Xiao J, Li QY, Tu JP, Chen XL, Chen XH, Liu QY, Liu H, Zhou XY, Zhao YZ, Wang HL. Stress response and tolerance mechanisms of ammonia exposure based on transcriptomics and metabolomics in Litopenaeus vannamei. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 180:491-500. [PMID: 31121556 DOI: 10.1016/j.ecoenv.2019.05.029] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Revised: 05/06/2019] [Accepted: 05/10/2019] [Indexed: 06/09/2023]
Abstract
Ammonia, one of the major limiting environment factors in aquaculture, may pose a threat to the shrimp growth, reproduction and survival. In this study, to understand molecular differences of transcriptomic and metabolomic responses and investigate the tolerance mechanisms underlying ammonia stress in Litopenaeus vannamei, ammonia-tolerant family (LV-AT) and ammonia-sensitive family (LV-AS) of these two extreme families were exposed to high-concentration (NH4Cl, 46 mg/L) ammonia for 24 h. The comparative transcriptome analysis between ammonia-treated and control (LV-C) groups revealed involvement of immune defense, cytoskeleton remodeling, antioxidative system and metabolic pathway in ammonia-stress response of L. vannamei. Likewise, metabolomics analysis showed that ammonia exposure could disturb amino acid metabolism, nucleotide metabolism and lipid metabolism, with metabolism related-genes changed according to RNA-seq analysis. The comparison of metabolite and transcript profiles between LV-AT and LV-AS indicated that LV-AT used the enhanced glycolysis and tricarboxylic acid (TCA) cycle strategies for energy supply and ammonia excretion to adapt high-concentration ammonia. Furthermore, some of genes involved in the detoxification and ammonia excretion were highly expressed in LV-AT. We speculate that the higher ability of ammonia excretion and detoxification and the accelerated energy metabolism for energy supplies might be the adaptive strategies for LV-AT relative to LV-AS after ammonia stress. Collectively, the combination of transcriptomics and metabolomics results will greatly contribute to incrementally understand the stress responses on ammonia exposure to L. vannamei and supply molecular level support for evaluating the environmental effects of ammonia on aquatic organisms. The results further constitute new sights on the potential molecular mechanisms of ammonia adaptive strategies in shrimps at the transcriptomics and metabolomics levels.
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Affiliation(s)
- Jie Xiao
- Key Lab of Freshwater Animal Breeding, Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction, Ministry of Education, College of Fishery Huazhong Agricultural University, Wuhan, PR China
| | - Qiang-Yong Li
- Guangxi Academy of Fishery Sciences, Guangxi Key Laboratory of Aquatic Genetic Breeding and Healthy Aquaculture, Guangxi, Nanning, 530021, China, PR China
| | - Jia-Peng Tu
- Key Lab of Freshwater Animal Breeding, Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction, Ministry of Education, College of Fishery Huazhong Agricultural University, Wuhan, PR China
| | - Xiu-Li Chen
- Guangxi Academy of Fishery Sciences, Guangxi Key Laboratory of Aquatic Genetic Breeding and Healthy Aquaculture, Guangxi, Nanning, 530021, China, PR China
| | - Xiao-Han Chen
- Guangxi Academy of Fishery Sciences, Guangxi Key Laboratory of Aquatic Genetic Breeding and Healthy Aquaculture, Guangxi, Nanning, 530021, China, PR China
| | - Qing-Yun Liu
- Guangxi Academy of Fishery Sciences, Guangxi Key Laboratory of Aquatic Genetic Breeding and Healthy Aquaculture, Guangxi, Nanning, 530021, China, PR China
| | - Hong Liu
- Key Lab of Freshwater Animal Breeding, Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction, Ministry of Education, College of Fishery Huazhong Agricultural University, Wuhan, PR China
| | - Xiao-Yun Zhou
- Key Lab of Freshwater Animal Breeding, Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction, Ministry of Education, College of Fishery Huazhong Agricultural University, Wuhan, PR China
| | - Yong-Zhen Zhao
- Guangxi Academy of Fishery Sciences, Guangxi Key Laboratory of Aquatic Genetic Breeding and Healthy Aquaculture, Guangxi, Nanning, 530021, China, PR China.
| | - Huan-Ling Wang
- Key Lab of Freshwater Animal Breeding, Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction, Ministry of Education, College of Fishery Huazhong Agricultural University, Wuhan, PR China.
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Shrivastava J, Ndugwa M, Caneos W, De Boeck G. Physiological trade-offs, acid-base balance and ion-osmoregulatory plasticity in European sea bass (Dicentrarchus labrax) juveniles under complex scenarios of salinity variation, ocean acidification and high ammonia challenge. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2019; 212:54-69. [PMID: 31075620 DOI: 10.1016/j.aquatox.2019.04.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 04/30/2019] [Accepted: 04/30/2019] [Indexed: 06/09/2023]
Abstract
In this era of global climate change, ocean acidification is becoming a serious threat to the marine ecosystem. Despite this, it remains almost unknown how fish will respond to the co-occurrence of ocean acidification with other conventional environmental perturbations typically salinity fluctuation and high ammonia threat. Therefore, the present work evaluated the interactive effects of elevated pCO2, salinity reduction and high environmental ammonia (HEA) on the ecophysiological performance of European sea bass (Dicentrarchus labrax). Fish were progressively acclimated to seawater (32 ppt), to brackish water (10 ppt) and to hyposaline water (2.5 ppt). Following acclimation to different salinities for at least two weeks, fish were exposed to CO2-induced water acidification representing present-day (control pCO2, 400 μatm, LoCO2) and future (high pCO2, 1000 μatm, HiCO2) sea-surface CO2 level for 3, 7 and 21 days. At the end of each exposure period, fish were challenged with HEA for 6 h (1.18 mM representing 50% of 96 h LC50). Results show that, in response to the individual HiCO2 exposure, fish within each salinity compensated for blood acidosis. Fish subjected to HiCO2 were able to maintain ammonia excretion rate (Jamm) within control levels, suggesting that HiCO2 exposure alone had no impact on Jamm at any of the salinities. For 32 and 10 ppt fish, up-regulated expression of Na+/K+-ATPase was evident in all exposure groups (HEA, HiCO2 and HEA/HiCO2 co-exposed), whereas Na+/K+/2Cl- co-transporter was up-regulated mainly in HiCO2 group. Plasma glucose and lactate content were augmented in all exposure conditions for all salinity regimes. During HEA and HEA/HiCO2, Jamm was inhibited at different time points for all salinities, which resulted in a significant build-up of ammonia in plasma and muscle. Branchial expressions of Rhesus glycoproteins (Rhcg isoforms and Rhbg) were upregulated in response to HiCO2 as well as HEA at 10 ppt, with a more moderate response in 32 ppt groups. Overall, our findings denote that the adverse effect of single exposures of ocean acidification or HEA is exacerbated when present together, and suggests that fish are more vulnerable to these environmental threats at low salinities.
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Affiliation(s)
- Jyotsna Shrivastava
- Systemic Physiological and Ecotoxicological Research, Department of Biology, University of Antwerp, Groenenborgerlaan 171, BE-2020 Antwerp, Belgium.
| | - Moses Ndugwa
- Systemic Physiological and Ecotoxicological Research, Department of Biology, University of Antwerp, Groenenborgerlaan 171, BE-2020 Antwerp, Belgium
| | - Warren Caneos
- Systemic Physiological and Ecotoxicological Research, Department of Biology, University of Antwerp, Groenenborgerlaan 171, BE-2020 Antwerp, Belgium
| | - Gudrun De Boeck
- Systemic Physiological and Ecotoxicological Research, Department of Biology, University of Antwerp, Groenenborgerlaan 171, BE-2020 Antwerp, Belgium
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Wang Y, Pasparakis C, Mager EM, Stieglitz JD, Benetti D, Grosell M. Ontogeny of urea and ammonia transporters in mahi-mahi (Coryphaena hippurus) early life stages. Comp Biochem Physiol A Mol Integr Physiol 2019; 229:18-24. [PMID: 30503629 DOI: 10.1016/j.cbpa.2018.11.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Accepted: 11/25/2018] [Indexed: 01/17/2023]
Abstract
The mechanism(s) of ammonia and urea excretion in freshwater fish have received considerable attention; however, parallel investigations of seawater fish, specifically in the early life stages are scarce. The first objective of this study was to evaluate the patterns of ammonia and urea excretion in mahi-mahi (Coryphaena hippurus) up to 102 hours post fertilization (hpf). Similar to other teleosts, mahi embryos are ureotelic before hatch and gradually switch to being ammoniotelic around the time of hatch. The second objective was to characterize mRNA levels of ammonia transporters (Rhag, Rhbg, Rhcg1 and Rhcg2), as well as urea transporter (UT) and sodium hydrogen exchangers (NHE3 and NHE2) during mahi development. As predicted, the mRNA levels of the Rhesus glycoprotein (Rh) genes, especially Rhag, Rhbg and the UT gene were highly consistent with the ontogeny of ammonia and urea excretion rates. Further, the localization of each transporter was examined in larvae collected at 60 and 102 hpf using in situ hybridization. Rhag was expressed in the gills, yolk sac, and operculum. Rhbg was expressed in the gills and upper mouth. Rhcg1 and NHE3 were co-localized in the sub-operculum, and Rhcg2 was expressed in the skin. Together, these results indicate that urea excretion is critical for ammonia detoxification during embryonic development and that Rh proteins are involved in ammonia excretion via gills and yolk sac, possibly facilitated by NHE3.
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Affiliation(s)
- Y Wang
- RSMAS, University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149, United States.
| | - C Pasparakis
- RSMAS, University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149, United States
| | - E M Mager
- RSMAS, University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149, United States; Department of Biological Sciences & Advanced Environmental Research Institute, University of North Texas, Denton, TX 76203, United States
| | - J D Stieglitz
- RSMAS, University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149, United States
| | - D Benetti
- RSMAS, University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149, United States
| | - M Grosell
- RSMAS, University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149, United States
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Egnew N, Renukdas N, Ramena Y, Yadav AK, Kelly AM, Lochmann RT, Sinha AK. Physiological insights into largemouth bass (Micropterus salmoides) survival during long-term exposure to high environmental ammonia. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2019; 207:72-82. [PMID: 30530206 DOI: 10.1016/j.aquatox.2018.11.027] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2018] [Revised: 11/29/2018] [Accepted: 11/30/2018] [Indexed: 06/09/2023]
Abstract
Waterborne ammonia is an environmental pollutant that is toxic to all aquatic animals. However, ammonia induced toxicity as well as compensatory mechanisms to defend against high environmental ammonia (HEA) are not well documented at present for largemouth bass (Micropterus salmoides), a high value fish for culture and sport fisheries in the United States. To provide primary information on the sensitivity of this species to ammonia toxicity, a 96 h-LC50 test was conducted. Thereafter, responses at physiological, ion-regulatory and transcript levels were determined to get insights into the underlying adaptive strategies to ammonia toxicity. For this purpose, fish were progressively exposed to HEA (8.31 mg/L representing 25% of 96 h-LC50) for 3, 7, 14, 21 and 28 days. Temporal effects of HEA on oxygen consumption rate (MO2), ammonia and urea dynamics, plasma ions (Na+, Cl- and K+), branchial Na+/K+-ATPase (NKA) and H+-ATPase activity, muscle water content (MWC), energy store (glycogen, lipid and protein) as well as branchial mRNA expression of Rhesus (Rh) glycoproteins were assessed. Probit analysis showed that 96 h-LC50 of (total) ammonia (as NH4HCO3) at 25 °C and pH 7.8 was 33.24 mg/L. Results from sub-lethal end-points shows that ammonia excretion rate (Jamm) was strongly inhibited after 7 days of HEA, but was unaffected at 3, 14 and 21 days. At 28 days fish were able to increase Jamm efficiently and concurrently, plasma ammonia re-established to the basal level. Urea production was increased as evidenced by a considerable elevation of plasma urea, but urea excretion rate remained unaltered. Expression of Rhcg isoform (Rhcg2) mRNA was up-regulated in parallel with restored or increased Jamm, suggesting its ammonia excreting role in largemouth bass. Exposure to HEA also displayed pronounced augmentations in NKA activity, exemplified by a rise in plasma [Na+]. Furthermore, [K+], [Cl-] and MWC homeostasis were disrupted followed by recovery to the control levels. H+-ATPase activity was elevated but NKA did not appear to function preferentially as a Na+/NH4+-ATPase. From 14 days onwards MO2 was depressed, potentially an attempt towards minimizing catabolism. Glycogen content in liver and muscle were temporarily depleted, whereas a remarkable increment in protein was evident at the last exposure period. Overall, these data suggest that ammonia induced toxicity can disturb several biological processes in largemouth bass, however, it can adapt to the long-term sub-lethal ammonia concentrations by activating various components of ammonia excretory, ion-regulatory and metabolic pathways.
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Affiliation(s)
- Nathan Egnew
- Department of Aquaculture and Fisheries, University of Arkansas at Pine Bluff, 1200 North University Drive, Pine Bluff, 71601, AR, USA.
| | - Nilima Renukdas
- Department of Aquaculture and Fisheries, University of Arkansas at Pine Bluff, 1200 North University Drive, Pine Bluff, 71601, AR, USA
| | - Yathish Ramena
- Department of Aquaculture and Fisheries, University of Arkansas at Pine Bluff, 1200 North University Drive, Pine Bluff, 71601, AR, USA; Great Salt Lake Brine Shrimp Cooperative, Inc., 1750 W 2450 S, Ogden, 84401, UT, USA
| | - Amit K Yadav
- Aquaculture Research Institute, Department of Animal and Veterinary Science, University of Idaho, Moscow, 83844, ID, USA
| | - Anita M Kelly
- Department of Aquaculture and Fisheries, University of Arkansas at Pine Bluff, 1200 North University Drive, Pine Bluff, 71601, AR, USA
| | - Rebecca T Lochmann
- Department of Aquaculture and Fisheries, University of Arkansas at Pine Bluff, 1200 North University Drive, Pine Bluff, 71601, AR, USA
| | - Amit Kumar Sinha
- Department of Aquaculture and Fisheries, University of Arkansas at Pine Bluff, 1200 North University Drive, Pine Bluff, 71601, AR, USA.
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41
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Exercise improves growth, alters physiological performance and gene expression in common carp (Cyprinus carpio). Comp Biochem Physiol A Mol Integr Physiol 2018; 226:38-48. [DOI: 10.1016/j.cbpa.2018.08.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2018] [Revised: 08/04/2018] [Accepted: 08/13/2018] [Indexed: 01/09/2023]
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Gilmour KM, Perry SF. Conflict and Compromise: Using Reversible Remodeling to Manage Competing Physiological Demands at the Fish Gill. Physiology (Bethesda) 2018; 33:412-422. [DOI: 10.1152/physiol.00031.2018] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The structural features of the fish gill necessary for oxygen uptake also favor undesirable, passive movements of ions and water. Reversible gill remodeling is one solution to this conflict. Cell masses that limit functional surface area are lost when oxygen availability decreases in hypoxia or oxygen demand increases with exercise or high temperature. However, much remains to be learned about how widespread reversible gill remodeling is among fish species, and how and why it occurs.
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Affiliation(s)
| | - Steve F. Perry
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
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43
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Abstract
During water-land transition, ancient fishes acquired the ability to breathe air, but air-breathing engendered problems in nitrogenous waste excretion. Nitrogen is a fundamental component of amino acids, proteins, and nucleic acids, and the degradation of these nitrogen-containing compounds releases ammonia. Ammonia is toxic and must be removed. Fishes in water excrete ammonia as the major nitrogenous waste through gills, but gills of air-breathing fishes are modified for air-breathing or largely replaced by air-breathing organs. Notably, fishes emerged from water can no longer excrete ammonia effectively because of a lack of water to flush the gills. Hence, ancient fishes that participated in water-land transition must have developed means to deal with ammonia toxicity. Extant air-breathing fishes, particularly amphibious ones, can serve as models to examine adaptations which might have facilitated the emergence of ancient fishes from water. Some of these fishes can actively emerge from water and display complex behaviors on land, while a few can burrow into mud and survive for years during drought. Many of them are equipped with mechanisms to ameliorate ammonia toxicity during emersion. In this review, the mechanisms adopted by air-breathing fishes to deal with ammonia toxicity during emersion were organized into seven disparate strategies. In addition, eight extant air-breathing fishes with distinctive terrestrial behaviors and peculiar natural habitats were selected to describe in detail how these seven strategies could be adopted in disparate combinations to ameliorate ammonia toxicity during emersion.
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Livingston MD, Bhargav VV, Turko AJ, Wilson JM, Wright PA. Widespread use of emersion and cutaneous ammonia excretion in Aplocheiloid killifishes. Proc Biol Sci 2018; 285:rspb.2018.1496. [PMID: 30111602 DOI: 10.1098/rspb.2018.1496] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 07/17/2018] [Indexed: 11/12/2022] Open
Abstract
The invasion of land required amphibious fishes to evolve new strategies to avoid toxic ammonia accumulation in the absence of water flow over the gills. We investigated amphibious behaviour and nitrogen excretion strategies in six phylogenetically diverse Aplocheiloid killifishes (Anablepsoides hartii, Cynodonichthys hildebrandi, Rivulus cylindraceus, Kryptolebias marmoratus, Fundulopanchax gardneri, and Aplocheilus lineatus) in order to determine if a common strategy evolved. All species voluntarily emersed (left water) over several days, and also in response to environmental stressors (low O2, high temperature). All species were ammoniotelic in water and released gaseous ammonia (NH3 volatilization) during air exposure as the primary route for nitrogen excretion. Metabolic depression, urea synthesis, and/or ammonia accumulation during air exposure were not common strategies used by these species. Immunostaining revealed the presence of ammonia-transporting Rhesus proteins (Rhcg1 and Rhcg2) in the skin of all six species, indicating a shared mechanism for ammonia volatilization. We also found Rhcg in the skin of several other fully aquatic fishes, implying that cutaneous ammonia excretion is not exclusive to amphibious fishes. Overall, our results demonstrate that similar nitrogen excretion strategies while out of water were used by all killifish species tested; possibly the result of shared ancestral amphibious traits, phenotypic convergence, or a combination of both.
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Affiliation(s)
- Michael D Livingston
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada N1G 2W1
| | - Vikram V Bhargav
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada N1G 2W1
| | - Andy J Turko
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada N1G 2W1
| | - Jonathan M Wilson
- Department of Biology, Wilfrid Laurier University, ON, Canada N2 L 3C5
| | - Patricia A Wright
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada N1G 2W1
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45
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Fehsenfeld S, Wood CM. Section-specific expression of acid-base and ammonia transporters in the kidney tubules of the goldfish Carassius auratus and their responses to feeding. Am J Physiol Renal Physiol 2018; 315:F1565-F1582. [PMID: 30089033 DOI: 10.1152/ajprenal.00510.2017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
In teleost fishes, renal contributions to acid-base and ammonia regulation are often neglected compared with the gills. In goldfish, increased renal acid excretion in response to feeding was indicated by increased urine ammonia and inorganic phosphate concentrations and decreased urine pH. By microdissecting the kidney tubules and performing quantitative real-time PCR and/or immunohistochemistry, we profiled the section-specific expression of glutamate dehydrogenase (GDH), glutamine synthetase (GS), Na+/H+-exchanger 3 (NHE3), carbonic anhydrase II (CAIIa), V-H+-ATPase subunit 1b, Cl-/ HCO3- -exchanger 1 (AE1), Na+/ HCO3- -cotransporter 1 (NBC1), Na+/K+-ATPase subunit 1α, and Rhesus-proteins Rhbg, Rhcg1a, and Rhcg1b. Here, we show for the first time that 1) the proximal tubule appears to be the major site for ammoniagenesis, 2) epithelial transporters are differentially expressed along the renal tubule, and 3) a potential feeding-related "acidic tide" results in the differential regulation of epithelial transporters, resembling the mammalian renal response to a metabolic acidosis. Specifically, GDH and NHE3 mRNAs were upregulated and GS downregulated in the proximal tubule upon feeding, suggesting this section as a major site for ammoniagenesis and acid secretion. The distal tubule may play a major role in renal ammonia secretion, with feeding-induced upregulation of mRNA and protein for apical NHE3, cytoplasmic CAIIa, universal Rhcg1a and apical Rhcg1b, and downregulation of basolateral Rhbg and AE1. Changes in mRNA expression of the Wolffian ducts and bladder suggest supporting roles in fine-tuning urine composition. The present study verifies an important renal contribution to acid-base balance and emphasizes that studies looking at the whole kidney may overlook key section-specific responses.
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Affiliation(s)
- Sandra Fehsenfeld
- University of British Columbia, Department of Zoology , Vancouver , Canada
| | - Chris M Wood
- University of British Columbia, Department of Zoology , Vancouver , Canada
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46
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Zimmer AM, Wright PA, Wood CM. Ammonia and urea handling by early life stages of fishes. ACTA ACUST UNITED AC 2018; 220:3843-3855. [PMID: 29093184 DOI: 10.1242/jeb.140210] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Nitrogen metabolism in fishes has been a focus of comparative physiologists for nearly a century. In this Review, we focus specifically on early life stages of fishes, which have received considerable attention in more recent work. Nitrogen metabolism and excretion in early life differs fundamentally from that of juvenile and adult fishes because of (1) the presence of a chorion capsule in embryos that imposes a limitation on effective ammonia excretion, (2) an amino acid-based metabolism that generates a substantial ammonia load, and (3) the lack of a functional gill, which is the primary site of nitrogen excretion in juvenile and adult fishes. Recent findings have shed considerable light on the mechanisms by which these constraints are overcome in early life. Perhaps most importantly, the discovery of Rhesus (Rh) glycoproteins as ammonia transporters and their expression in ion-transporting cells on the skin of larval fishes has transformed our understanding of ammonia excretion by fishes in general. The emergence of larval zebrafish as a model species, together with genetic knockdown techniques, has similarly advanced our understanding of ammonia and urea metabolism and excretion by larval fishes. It has also now been demonstrated that ammonia excretion is one of the primary functions of the developing gill in rainbow trout larvae, leading to new hypotheses regarding the physiological demands driving gill development in larval fishes. Here, we highlight and discuss the dramatic changes in nitrogen handling that occur over early life development in fishes.
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Affiliation(s)
- Alex M Zimmer
- Department of Biology, University of Ottawa, Ottawa, ON, Canada K1N 6N57
| | - Patricia A Wright
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada N1G 2W1
| | - Chris M Wood
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada V6T 1Z4.,Department of Biology, McMaster University, Hamilton, ON, Canada L8S 4K1
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47
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Grobler JMB, Wood CM. The effects of high environmental ammonia on the structure of rainbow trout hierarchies and the physiology of the individuals therein. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2018; 195:77-87. [PMID: 29289872 DOI: 10.1016/j.aquatox.2017.12.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Revised: 12/09/2017] [Accepted: 12/17/2017] [Indexed: 06/07/2023]
Abstract
Our goals were: (i) to determine whether sublethal concentrations of water-borne ammonia would prevent the formation of a dominance hierarchy, or alter its structure, in groups of 4 juvenile trout; (ii) to investigate the behavioral and physiological responses of individuals of different social rank exposed to a concentration of ammonia that still allowed hierarchy formation. Social hierarchies were created by using a technique in which a food delivery system that created competition also served to isolate individual fish for respirometry. Groups of 4 fish were exposed to elevated ammonia (NH4HCO3) 12 h before first feeding; aggression was recorded by video camera during morning feedings. Experimental ammonia concentrations were 700, 1200 and 1500 μmol L-1 at pH 7.3, 12 °C (9.8, 16.8, and 21.0 mg L-1 as total ammonia-N, or 0.0515, 0.0884, and 0.1105 mg L-1 as NH3-N). Aggression was severely reduced by 1200 and abolished by 1500 μmol L-1 total ammonia, such that hierarchies did not form. However, groups exposed to 700 μmol L-1 total ammonia still formed stable hierarchies but displayed lower levels of aggression in comparison to control hierarchies. Exposure continued for 11 days. Physiological parameters were recorded on day 5 (end of period 1) and day 10 (end of period 2), while feeding and plasma cortisol were measured on day 11. In control hierarchies, dominant (rank 1) trout generally exhibited higher growth rates, greater increases in condition factor, higher food consumption, and lower cortisol levels than did fish of ranks 2, 3, and 4. In comparison to controls, the 700 μmol L-1 total ammonia hierarchies generally displayed lower growth, lower condition factor increases, lower O2 consumption, lower cortisol levels, but similar feeding patterns, with smaller physiological differences amongst ranks during period 1. Effects attenuated during period 2, as aggression and physiological measures returned towards control levels, indicating both behavioral and physiological acclimation to ammonia. These disturbances in social behavior and associated physiology occurred at an ammonia concentration in the range of regulatory significance and relevance to aquaculture.
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Affiliation(s)
- Josias M B Grobler
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada.
| | - Chris M Wood
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada; Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, B.C., V6T 1Z4, Canada.
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48
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Chng YR, Ong JLY, Ching B, Chen XL, Hiong KC, Wong WP, Chew SF, Lam SH, Ip YK. Molecular characterization of three Rhesus glycoproteins from the gills of the African lungfish, Protopterus annectens, and effects of aestivation on their mRNA expression levels and protein abundance. PLoS One 2017; 12:e0185814. [PMID: 29073147 PMCID: PMC5657625 DOI: 10.1371/journal.pone.0185814] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 09/20/2017] [Indexed: 11/19/2022] Open
Abstract
African lungfishes are ammonotelic in water. They can aestivate for long periods on land during drought. During aestivation, the gills are covered with dried mucus and ammonia excretion ceases. In fishes, ammonia excretion through the gills involves Rhesus glycoproteins (RhGP/Rhgp). This study aimed to obtain the complete cDNA coding sequences of rhgp from the gills of Protopterus annectens, and to determine their branchial mRNA and protein expression levels during the induction, maintenance and arousal phases of aestivation. Three isoforms of rhgp (rhag, rhbg and rhcg) were obtained in the gills of P. annectens. Their complete cDNA coding sequences ranged between 1311 and 1398 bp, coding for 436 to 465 amino acids with estimated molecular masses between 46.8 and 50.9 kDa. Dendrogramic analyses indicated that Rhag was grouped closer to fishes, while Rhbg and Rhcg were grouped closer to tetrapods. During the induction phase, the protein abundance of Rhag, but not its transcript level, was down-regulated in the gills, suggesting that there could be a decrease in the release of ammonia from the erythrocytes to the plasma. Furthermore, the branchial transcript levels of rhbg and rhcg decreased significantly, in preparation for the subsequent shutdown of gill functions. During the maintenance phase, the branchial expression levels of rhag/Rhag, rhbg/Rhbg and rhcg/Rhcg decreased significantly, indicating that their transcription and translation were down-regulated. This could be part of an overall mechanism to shut down branchial functions and save metabolic energy used for transcription and translation. It could also be regarded as an adaptive response to stop ammonia excretion. During the arousal phase, it is essential for the lungfish to regain the ability to excrete ammonia. Indeed, the protein abundance of Rhag, Rhbg and Rhcg recovered to the corresponding control levels after 1 day or 3 days of recovery from 6 months of aestivation.
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Affiliation(s)
- You R. Chng
- Department of Biological Sciences, National University of Singapore, Singapore
| | - Jasmine L. Y. Ong
- Department of Biological Sciences, National University of Singapore, Singapore
| | - Biyun Ching
- Department of Biological Sciences, National University of Singapore, Singapore
| | - Xiu L. Chen
- Department of Biological Sciences, National University of Singapore, Singapore
| | - Kum C. Hiong
- Department of Biological Sciences, National University of Singapore, Singapore
| | - Wai P. Wong
- Department of Biological Sciences, National University of Singapore, Singapore
| | - Shit F. Chew
- Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University, Singapore
| | - Siew H. Lam
- Department of Biological Sciences, National University of Singapore, Singapore
- NUS Environmental Research Institute, National University of Singapore, Singapore
| | - Yuen K. Ip
- Department of Biological Sciences, National University of Singapore, Singapore
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49
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Chen XL, Zhang B, Chng YR, Ong JLY, Chew SF, Wong WP, Lam SH, Nakada T, Ip YK. Ammonia exposure affects the mRNA and protein expression levels of certain Rhesus glycoproteins in the gills of climbing perch. ACTA ACUST UNITED AC 2017; 220:2916-2931. [PMID: 28576822 DOI: 10.1242/jeb.157123] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 05/30/2017] [Indexed: 01/08/2023]
Abstract
The freshwater climbing perch, Anabas testudineus, is an obligate air-breathing and euryhaline teleost capable of active ammonia excretion and tolerant of high concentrations of environmental ammonia. As Rhesus glycoproteins (RhGP/Rhgp) are known to transport ammonia, this study aimed to obtain the complete cDNA coding sequences of various rhgp isoforms from the gills of A. testudineus, and to determine their mRNA and protein expression levels during 6 days of exposure to 100 mmol l-1 NH4Cl. The subcellular localization of Rhgp isoforms in the branchial epithelium was also examined in order to elucidate the type of ionocyte involved in active ammonia excretion. Four rhgp (rhag, rhbg, rhcg1 and rhcg2) had been identified from the gills of A. testudineus They had conserved amino acid residues for NH4+ binding, NH4+ deprotonation, channel gating and lining of the vestibules. Despite inwardly directed NH3 and NH4+ gradients, there were significant increases in the mRNA expression levels of the four branchial rhgp in A. testudineus at certain time points during 6 days of ammonia exposure, with significant increases in the protein abundances of Rhag and Rhcg2 on day 6. Immunofluorescence microscopy revealed a type of ammonia-inducible Na+/K+-ATPase α1c-immunoreactive ionocyte with apical Rhag and basolateral Rhcg2 in the gills of fish exposed to ammonia for 6 days. Hence, active ammonia excretion may involve NH4+ entering the ionocyte through the basolateral Rhcg2 and being excreted through the apical Rhag, driven by a transapical membrane electrical potential generated by the apical cystic fibrosis transmembrane conductance regulator Cl- channel, as suggested previously.
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Affiliation(s)
- Xiu L Chen
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore
| | - Biyan Zhang
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore
| | - You R Chng
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore
| | - Jasmine L Y Ong
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore
| | - Shit F Chew
- Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University, 1 Nanyang Walk, Singapore 637616, Republic of Singapore
| | - Wai P Wong
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore
| | - Siew H Lam
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore.,NUS Environmental Research Institute, National University of Singapore, Kent Ridge, Singapore 117411, Republic of Singapore
| | - Tsutomu Nakada
- Department of Molecular Pharmacology, Shinshu University School of Medicine, Matsumoto, Nagano 390-8621, Japan
| | - Yuen K Ip
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore
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50
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Yeam CT, Chng YR, Ong JLY, Wong WP, Chew SF, Ip YK. Molecular characterization of two Rhesus glycoproteins from the euryhaline freshwater white-rimmed stingray, Himantura signifer, and changes in their transcript levels and protein abundance in the gills, kidney, and liver during brackish water acclimation. J Comp Physiol B 2017; 187:911-929. [PMID: 28324156 DOI: 10.1007/s00360-017-1067-8] [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: 09/23/2016] [Revised: 02/05/2017] [Accepted: 02/21/2017] [Indexed: 11/29/2022]
Abstract
Himantura signifer is a freshwater stingray which inhabits rivers in Southeast Asia. It is ammonotelic in fresh water, but retains the capacities of urea synthesis and ureosmotic osmoregulation to survive in brackish water. This study aimed to elucidate the roles of Rhesus glycoproteins (Rhgp), which are known to transport ammonia, in conserving nitrogen (N) in H. signifer during brackish water acclimation when N became limited resulting from increased hepatic urea synthesis. The complete coding sequence of rhbg from H. signifer consisted of 1383 bp, encoding 460 amino acids with an estimated molecular mass of 50.5 kDa, while that of rhcg comprised 1395 bp, encoding for 464 amino acids with an estimated molecular mass of 50.8 kDa. The deduced amino sequences of Rhbg and Rhcg contained ammonia binding sites, which could recruit NH4+ to be deprotonated, and a hydrophobic pore with two histidine residues, which could mediate the transport of NH3. Our results indicated for the first time that brackish water acclimation resulted in significant decreases in the expression levels of rhbg/Rhbg and rhcg/Rhcg in the gills of H. signifer, which offered a mechanistic explanation of brackish water-related decreased ammonia excretion reported elsewhere. Furthermore, rhbg/Rhbg expression levels increased significantly in the liver of H. signifer during brackish water acclimation, indicating that the ammonia produced by extra-hepatic tissues and released into the blood could be channeled into the liver for increased urea synthesis. Overall, these results lend support to the proposition that H. signifer becomes N-limited upon utilizing urea as an osmolyte in brackish water.
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Affiliation(s)
- Cheng T Yeam
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore, 117543, Singapore
| | - You R Chng
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore, 117543, Singapore
| | - Jasmine L Y Ong
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore, 117543, Singapore
| | - Wai P Wong
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore, 117543, Singapore
| | - Shit F Chew
- Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University, 1 Nanyang Walk, Singapore, 637616, Singapore
| | - Yuen K Ip
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore, 117543, Singapore. .,The Tropical Marine Science Institute, National University of Singapore, Kent Ridge, Singapore, 119227, Singapore.
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