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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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2
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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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3
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Doyle D, Carney Almroth B, Sundell K, Simopoulou N, Sundh H. Transport and Barrier Functions in Rainbow Trout Trunk Skin Are Regulated by Environmental Salinity. Front Physiol 2022; 13:882973. [PMID: 35634157 PMCID: PMC9136037 DOI: 10.3389/fphys.2022.882973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 04/29/2022] [Indexed: 11/20/2022] Open
Abstract
The mechanisms underpinning ionic transport and barrier function have been relatively well characterised in amphibians and fish. In teleost fish, these processes have mostly been characterised in the gill and intestine. In contrast, these processes remain much less clear for the trunk skin of fish. In this study, we measured barrier function and active transport in the trunk skin of the rainbow trout, using the Ussing chamber technique. The effects of epithelial damage, skin region, salinity, and pharmacological inhibition were tested. Skin barrier function decreased significantly after the infliction of a superficial wound through the removal of scales. Wound healing was already underway after 3 h and, after 24 h, there was no significant difference in barrier function towards ions between the wounded and control skin. In relation to salinity, skin permeability decreased drastically following exposure to freshwater, and increased following exposure to seawater. Changes in epithelial permeability were accompanied by salinity-dependent changes in transepithelial potential and short-circuit current. The results of this study support the idea that barrier function in rainbow trout trunk skin is regulated by tight junctions that rapidly respond to changes in salinity. The changes in transepithelial permeability and short circuit current also suggest the presence of an active transport component. Immunostaining and selective inhibition suggest that one active transport component is an apical V-ATPase. However, further research is required to determine the exact role of this transporter in the context of the trunk skin.
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Affiliation(s)
- D Doyle
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - B Carney Almroth
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - K Sundell
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - N Simopoulou
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - H Sundh
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
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4
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Marina G, Glover CN, Goss GG, Zimmer AM. The skin of adult rainbow trout is not a significant site of ammonia clearance from the blood. JOURNAL OF FISH BIOLOGY 2021; 99:1529-1534. [PMID: 34159596 DOI: 10.1111/jfb.14831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Revised: 05/14/2021] [Accepted: 06/17/2021] [Indexed: 06/13/2023]
Abstract
We hypothesized that the skin acts as an extrabranchial route for ammonia excretion in adult rainbow trout (Oncorhynchus mykiss) following high environmental ammonia (HEA) exposure. Trunks of control or HEA-exposed trout were perfused with saline containing 0 or 1 mmol l-1 NH4 + . Cutaneous ammonia excretion rates increased 2.5-fold following HEA exposure, however there was no difference in rates between trunks perfused with 0 or 1 mmol l-1 NH4 + . The skin is therefore capable of excreting its own ammonia load, but it does not clear circulating ammonia from the plasma.
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Affiliation(s)
- Giacomin Marina
- Department of Biological Sciences, CW 405, Biological Sciences Bldg, University of Alberta, Edmonton, Alberta, Canada
| | - Chris N Glover
- Department of Biological Sciences, CW 405, Biological Sciences Bldg, University of Alberta, Edmonton, Alberta, Canada
- Faculty of Science and Technology and Athabasca River Basin Research Institute, Athabasca University, Athabasca, Alberta, Canada
| | - Greg G Goss
- Department of Biological Sciences, CW 405, Biological Sciences Bldg, University of Alberta, Edmonton, Alberta, Canada
| | - Alex M Zimmer
- Department of Biological Sciences, CW 405, Biological Sciences Bldg, University of Alberta, Edmonton, Alberta, Canada
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5
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Adamek M, Teitge F, Baumann I, Jung-Schroers V, El Rahman SA, Paley R, Piackova V, Gela D, Kocour M, Rakers S, Bergmann SM, Ganter M, Steinhagen D. Koi sleepy disease as a pathophysiological and immunological consequence of a branchial infection of common carp with carp edema virus. Virulence 2021; 12:1855-1883. [PMID: 34269137 PMCID: PMC8288041 DOI: 10.1080/21505594.2021.1948286] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Gills of fish are involved in respiration, excretion and osmoregulation. Due to numerous interactions between these processes, branchial diseases have serious implications on fish health. Here, "koi sleepy disease" (KSD), caused by carp edema virus (CEV) infection was used to study physiological, immunological and metabolic consequences of a gill disease in fish. A metabolome analysis shows that the moderately hypoxic-tolerant carp can compensate the respiratory compromise related to this infection by various adaptations in their metabolism. Instead, the disease is accompanied by a massive disturbance of the osmotic balance with hyponatremia as low as 71.65 mmol L-1, and an accumulation of ammonia in circulatory blood causing a hyperammonemia as high as 1123.24 µmol L-1. At water conditions with increased ambient salt, the hydro-mineral balance and the ammonia excretion were restored. Importantly, both hyponatremia and hyperammonemia in KSD-affected carp can be linked to an immunosuppression leading to a four-fold drop in the number of white blood cells, and significant downregulation of cd4, tcr a2 and igm expression in gills, which can be evaded by increasing the ion concentration in water. This shows that the complex host-pathogen interactions within the gills can have immunosuppressive consequences, which have not previously been addressed in fish. Furthermore, it makes the CEV infection of carp a powerful model for studying interdependent pathological and immunological effects of a branchial disease in fish.
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Affiliation(s)
- Mikolaj Adamek
- Fish Disease Research Unit, Institute for Parasitology, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Felix Teitge
- Fish Disease Research Unit, Institute for Parasitology, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Ilka Baumann
- Fish Disease Research Unit, Institute for Parasitology, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Verena Jung-Schroers
- Fish Disease Research Unit, Institute for Parasitology, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Sahar Abd El Rahman
- Department of Virology, Faculty of Veterinary Medicine, Mansoura University, Mansoura Egypt
| | - Richard Paley
- Cefas Weymouth Laboratory, International Centre of Excellence for Aquatic Animal Health, Weymouth, Dorset, UK
| | - Veronica Piackova
- South Bohemian Research Centre of Aquaculture and Biodiversity of Hydrocenoses, Faculty of Fisheries and Protection of Waters, University of South Bohemia in Ceske Budejovice, Vodnany, Czech Republic
| | - David Gela
- South Bohemian Research Centre of Aquaculture and Biodiversity of Hydrocenoses, Faculty of Fisheries and Protection of Waters, University of South Bohemia in Ceske Budejovice, Vodnany, Czech Republic
| | - Martin Kocour
- South Bohemian Research Centre of Aquaculture and Biodiversity of Hydrocenoses, Faculty of Fisheries and Protection of Waters, University of South Bohemia in Ceske Budejovice, Vodnany, Czech Republic
| | - Sebastian Rakers
- Working Group Aquatic Cell Technology and Aquaculture, Fraunhofer Research Institution for Marine Biotechnology and Cell Technology, Lübeck, Germany
| | - Sven M Bergmann
- Institute of Infectology, Federal Research Institute for Animal Health, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Martin Ganter
- Clinic for Swine, Small Ruminants, Forensic Medicine and Ambulatory Service, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Dieter Steinhagen
- Fish Disease Research Unit, Institute for Parasitology, University of Veterinary Medicine Hannover, Hannover, Germany
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6
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Sørhus E, Donald CE, da Silva D, Thorsen A, Karlsen Ø, Meier S. Untangling mechanisms of crude oil toxicity: Linking gene expression, morphology and PAHs at two developmental stages in a cold-water fish. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 757:143896. [PMID: 33316527 DOI: 10.1016/j.scitotenv.2020.143896] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 11/17/2020] [Accepted: 11/17/2020] [Indexed: 06/12/2023]
Abstract
Early life stages of fish are highly sensitive to crude oil exposure and thus, short term exposures during critical developmental periods could have detrimental consequences for juvenile survival. Here we administered crude oil to Atlantic haddock (Melanogrammus aeglefinus) in short term (3-day) exposures at two developmental time periods: before first heartbeat, from gastrulation to cardiac cone stage (early), and from first heartbeat to one day before hatching (late). A frequent sampling regime enabled us to determine immediate PAH uptake, metabolite formation and gene expression changes. In general, the embryotoxic consequences of an oil exposure were more severe in the early exposure animals. Oil droplets on the eggshell resulted in severe cardiac and craniofacial abnormalities in the highest treatments. Gene expression changes of Cytochrome 1 a, b, c and d (cyp1a, b, c, d), Bone morphogenetic protein 10 (bmp10), ABC transporter b1 (abcb1) and Rh-associated G-protein (rhag) were linked to PAH uptake, occurrence of metabolites of phenanthrene and developmental and functional abnormalities. We detected circulation-independent, oil-induced gene expression changes and separated phenotypes linked to proliferation, growth and disruption of formation events at early and late developmental stages. Changes in bmp10 expression suggest a direct oil-induced effect on calcium homeostasis. Localized expression of rhag propose an impact on osmoregulation. Severe eye abnormalities were linked to possible inappropriate overexpression of cyp1b in the eyes. This study gives an increased knowledge about developmentally dependent effects of crude oil toxicity. Thus, our findings provide more knowledge and detail to new and several existing adverse outcome pathways of crude oil toxicity.
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Affiliation(s)
- Elin Sørhus
- Institute of Marine Research, Bergen, Norway.
| | | | - Denis da Silva
- Northwest Fisheries Science Center (NOAA), 2725 Montlake Blvd. East, Seattle, WA 98112-2097, USA
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7
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Li H, Lai Q, Yao Z, Liu Y, Gao P, Zhou K, Sun Z. Ammonia excretion and blood gas variation in naked carp (Gymnocypris przewalskii) exposed to acute hypoxia and high alkalinity. FISH PHYSIOLOGY AND BIOCHEMISTRY 2020; 46:1981-1990. [PMID: 32676986 DOI: 10.1007/s10695-020-00850-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Accepted: 07/07/2020] [Indexed: 06/11/2023]
Abstract
Naked carp (Gymnocypris przewalskii), endemic to the saline-alkaline Lake Qinghai, have the capacity to tolerate combined hypoxia and high alkalinity. This study evaluated the effect of the interaction between carbonate alkalinity and hypoxia on ammonia excretion and blood gas variation in naked carp. Naked carp were subjected to normoxic, hypoxic and reoxygenation phases at two different carbonate alkalinity levels (CA0 = 0 mmol/L; CA32 = 32 mmol/L) for 4 days. The ammonia excretion rate (JAmm) of the CA0 group rapidly decreased under hypoxia and recovered under normoxia for four consecutive days. The JAmm under CA32 also decreased under hypoxia and recovered to its previous level in the first 2 days. However, the JAmm under CA32 was lower than that under CA0. The blood pO2, sO2 of CA0 and CA32 group was significantly reduced under hypoxia, after which both groups recovered. Blood pCO2 of the CA32 group was lower than CA0 throughout the experiment. There were no changes in haematocrit of the naked carp exposed to carbonate alkalinity and hypoxia. The alkaline water increased the pH of the blood and contributed to increased haemoglobin O2 affinity. Overall, the present findings reveal that naked carp is a tolerant species that can maintain main ionic homeostasis under severe alkalinity and hypoxia. The high alkaline water is beneficial for naked carp to adapt to hypoxic environment.
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Affiliation(s)
- Hang Li
- Engineering Research Center for Saline-alkaline Fisheries, East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai, China
- Sino-US Joint Laboratory of Aquatic Animal Physiology, East China Sea Fisheries Research Institute, Chinese Academy of Fisheries Sciences, Shanghai, China
- National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, China
| | - Qifang Lai
- Engineering Research Center for Saline-alkaline Fisheries, East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai, China
- Sino-US Joint Laboratory of Aquatic Animal Physiology, East China Sea Fisheries Research Institute, Chinese Academy of Fisheries Sciences, Shanghai, China
| | - Zongli Yao
- Engineering Research Center for Saline-alkaline Fisheries, East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai, China.
- Sino-US Joint Laboratory of Aquatic Animal Physiology, East China Sea Fisheries Research Institute, Chinese Academy of Fisheries Sciences, Shanghai, China.
- , Shanghai, People's Republic of China.
| | - Yimeng Liu
- Engineering Research Center for Saline-alkaline Fisheries, East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai, China
- Sino-US Joint Laboratory of Aquatic Animal Physiology, East China Sea Fisheries Research Institute, Chinese Academy of Fisheries Sciences, Shanghai, China
| | - Pengcheng Gao
- Engineering Research Center for Saline-alkaline Fisheries, East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai, China
- Sino-US Joint Laboratory of Aquatic Animal Physiology, East China Sea Fisheries Research Institute, Chinese Academy of Fisheries Sciences, Shanghai, China
| | - Kai Zhou
- Engineering Research Center for Saline-alkaline Fisheries, East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai, China
- Sino-US Joint Laboratory of Aquatic Animal Physiology, East China Sea Fisheries Research Institute, Chinese Academy of Fisheries Sciences, Shanghai, China
| | - Zhen Sun
- Engineering Research Center for Saline-alkaline Fisheries, East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai, China
- Sino-US Joint Laboratory of Aquatic Animal Physiology, East China Sea Fisheries Research Institute, Chinese Academy of Fisheries Sciences, Shanghai, China
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8
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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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9
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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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10
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Clifford AM, Weinrauch AM, Edwards SL, Wilkie MP, Goss GG. Flexible ammonia handling strategies using both cutaneous and branchial epithelia in the highly ammonia-tolerant Pacific hagfish. Am J Physiol Regul Integr Comp Physiol 2017; 313:R78-R90. [PMID: 28515081 DOI: 10.1152/ajpregu.00351.2016] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 05/08/2017] [Accepted: 05/08/2017] [Indexed: 12/20/2022]
Abstract
Hagfish consume carrion, potentially exposing them to hypoxia, hypercapnia, and high environmental ammonia (HEA). We investigated branchial and cutaneous ammonia handling strategies by which Pacific hagfish (Eptatretus stoutii) tolerate and recover from high ammonia loading. Hagfish were exposed to HEA (20 mmol/l) for 48 h to elevate plasma total ammonia (TAmm) levels before placement into divided chambers for a 4-h recovery period in ammonia-free seawater where ammonia excretion (JAmm) was measured independently in the anterior and posterior compartments. Localized HEA exposures were also conducted by subjecting hagfish to HEA in either the anterior or posterior compartments. During recovery, HEA-exposed animals increased JAmm in both compartments, with the posterior compartment comprising ~20% of the total JAmm compared with ~11% in non-HEA-exposed fish. Plasma TAmm increased substantially when whole hagfish and the posterior regions were exposed to HEA. Alternatively, plasma TAmm did not elevate after anterior localized HEA exposure. JAmm was concentration dependent (0.05-5 mmol/l) across excised skin patches at up to eightfold greater rates than in skin sections that were excised from HEA-exposed hagfish. Skin excised from more posterior regions displayed greater JAmm than those from more anterior regions. Immunohistochemistry with hagfish-specific anti-rhesus glycoprotein type c (α-hRhcg; ammonia transporter) antibody was characterized by staining on the basal aspect of hagfish epidermis while Western blotting demonstrated greater expression of Rhcg in more posterior skin sections. We conclude that cutaneous Rhcg proteins are involved in cutaneous ammonia excretion by Pacific hagfish and that this mechanism could be particularly important during feeding.
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Affiliation(s)
- Alexander M Clifford
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada; .,Bamfield Marine Sciences Centre, Bamfield, British Columbia, Canada
| | - Alyssa M Weinrauch
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.,Bamfield Marine Sciences Centre, Bamfield, British Columbia, Canada
| | - Susan L Edwards
- Bamfield Marine Sciences Centre, Bamfield, British Columbia, Canada.,Department of Biology, Appalachian State University, Boone, North Carolina; and
| | - Michael P Wilkie
- Bamfield Marine Sciences Centre, Bamfield, British Columbia, Canada.,Department of Biology and Laurier Institute for Water Science, Wilfrid Laurier University, Waterloo, Ontario, Canada
| | - 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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11
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Jin J, Wang Y, Wu Z, Hergazy A, Lan J, Zhao L, Liu X, Chen N, Lin L. Transcriptomic analysis of liver from grass carp (Ctenopharyngodon idellus) exposed to high environmental ammonia reveals the activation of antioxidant and apoptosis pathways. FISH & SHELLFISH IMMUNOLOGY 2017; 63:444-451. [PMID: 28235639 DOI: 10.1016/j.fsi.2017.02.037] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Revised: 02/19/2017] [Accepted: 02/20/2017] [Indexed: 06/06/2023]
Abstract
High concentration of ammonia in aquatic system leads to detrimental effects on the health of aquatic animals. However, the mechanism underlying ammonia-induced toxicity is still not clear. To better understand the mechanism of ammonia toxicity effects on fish, juvenile grass carp was employed in the present study. RNA high-throughput sequencing technique was applied to analyze the total RNAs extracted from the liver of fish after 8 h post exposure to the water containing 2 mM NH4HCO3 which experimentally mimicked the high environmental ammonia (HEA). A total of 49,971,114 and 53,826,986 clean reads were obtained in control and 2 mM HEA group, respectively, in which there were 911 differently expressed genes (DEGs) including 563 up-regulated and 348 down-regulated genes. In addition, 10 DEGs were validated by quantitative PCR. These DEGs were involved in several pathways related with oxidative stress or apoptosis. Further analysis on oxidative stress, histopathology and cellular apoptosis in grass carp liver after HEA exposure revealed interesting findings. Increased reactive oxygen species (ROS) content and superoxide dismutase (SOD) activity together with the decreased catalase (CAT) activity were detected, which may be effected by DEGs and related pathways such as FOXO signaling pathway. The histopathology and TUNEL assays results confirmed that apoptosis was induced in liver when fish had suffered HEA. Combined with the results of transcriptomic experiments, c-Myc-Bax-Caspase9 apoptosis pathway could be involved in grass carp liver apoptosis induced by ammonia stress.
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Affiliation(s)
- Jiali Jin
- Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Yao Wang
- Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Zhixin Wu
- Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Abeer Hergazy
- Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Jiangfeng Lan
- Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Lijuan Zhao
- Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan, Hubei, 430070, China; Guangzhou Key Laboratory of Aquatic Animal Diseases and Waterfowl Breeding, College of Animal Sciences and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou, Guangdong, 510225, China
| | - Xiaoling Liu
- Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Nan Chen
- Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan, Hubei, 430070, China.
| | - Li Lin
- Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan, Hubei, 430070, China; Guangzhou Key Laboratory of Aquatic Animal Diseases and Waterfowl Breeding, College of Animal Sciences and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou, Guangdong, 510225, China.
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12
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Blair S, Wilkie M, Edwards S. Rh glycoprotein immunoreactivity in the skin and its role in extrabranchial ammonia excretion by the sea lamprey (Petromyzon marinus) in fresh water. CAN J ZOOL 2017. [DOI: 10.1139/cjz-2016-0120] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Aquatic organisms employ various strategies to excrete ammonia across the gills, skin, and (or) renal routes. During three different stages of their life cycle, we hypothesized that the basal vertebrate sea lamprey (Petromyzon marinus L., 1758) used the skin as a route for ammonia excretion. Measurements of ammonia excretion using divided flux chambers revealed that extrabranchial sites (skin plus renal) of ammonia excretion were quantitatively more important in larval sea lampreys, but following metamorphosis, the gills became the dominant route of excretion in juvenile sea lampreys. Despite the greater relative importance of the skin in the larval stage, Rh glycoprotein isoforms Rhbg, Rhcg1, and Rhcg2 were detected in the skin in all three sea lamprey life stages examined, but the patterns of expression were dependent on the life stage. We conclude that, during the relatively sedentary filter-feeding larval stage, extrabranchial routes play an equally important role as the gill in facilitating ammonia excretion. However, the gills by virtue of their extensive branchial vasculature become the dominant route of ammonia excretion following metamorphosis because of the need to offload greater amounts of ammonia arising from higher rates of basal ammonia production and the potential to excrete higher amounts of ammonia following ingestion of protein-rich blood in the parasitic stage.
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Affiliation(s)
- S.D. Blair
- Department of Biology, Appalachian State University, Boone, NC 28608, USA
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - M.P. Wilkie
- Department of Biology, Wilfrid Laurier University, Waterloo, ON N2L 3C5, Canada
- Department of Biology, Mount Allison University, Sackville, NB E4L 1G7, Canada
| | - S.L. Edwards
- Department of Biology, Appalachian State University, Boone, NC 28608, USA
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13
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Nitrogen metabolism in tambaqui (Colossoma macropomum), a neotropical model teleost: hypoxia, temperature, exercise, feeding, fasting, and high environmental ammonia. J Comp Physiol B 2016; 187:135-151. [DOI: 10.1007/s00360-016-1027-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 07/29/2016] [Accepted: 08/03/2016] [Indexed: 12/25/2022]
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14
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Bucking C. A broader look at ammonia production, excretion, and transport in fish: a review of impacts of feeding and the environment. J Comp Physiol B 2016; 187:1-18. [PMID: 27522221 DOI: 10.1007/s00360-016-1026-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 07/22/2016] [Accepted: 07/29/2016] [Indexed: 12/23/2022]
Abstract
For nearly a century, researchers have studied ammonia production and excretion in teleost fish. Stemming from past investigations a body of knowledge now exists on various aspects including biochemical mechanisms of ammonia formation and specific routes and tissues used for ammonia transport, culminating in a current detailed theoretical model of branchial transport, including the molecular identities of the moieties involved. However, typical studies examining ammonia balance use routine laboratory conditions and fasted fish. While avoiding additional variables that influence nitrogen balance, these studies are arguably idealistic and do not reflect the natural variety of conditions that fish encounter. Further studies have revealed the impacts of extrinsic factors (e.g. salinity, pH, temperature) on ammonia handling in fasted fish whereas others have explored intrinsic factors, such as life history and developmental impacts. One routine challenge for ammonia balance that fish encounter is feeding and digestion. Fortunately, many new studies have revealed the impact of feeding and digestion on several aspects of ammonia balance; from production to excretion and to transport, and several have done so incorporating supplemental extrinsic and/or intrinsic factors. Together, these complex studies reveal realistic responses to multifactorial challenges encountered by animals in the wild and begin to provide a holistic view of ammonia balance in freshwater teleost fish.
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Affiliation(s)
- Carol Bucking
- Department of Biology, Farquharson Life Science Building, York University, Toronto, ON, M3J 1P3, Canada.
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15
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Boyle D, Blair SD, Chamot D, Goss GG. Characterization of developmental Na(+) uptake in rainbow trout larvae supports a significant role for Nhe3b. Comp Biochem Physiol A Mol Integr Physiol 2016; 201:30-36. [PMID: 27350321 DOI: 10.1016/j.cbpa.2016.06.027] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 06/22/2016] [Accepted: 06/22/2016] [Indexed: 11/26/2022]
Abstract
Developing freshwater fish must compensate for the loss of ions, including sodium (Na(+)), to the environment. In this study, we used a radiotracer flux approach and pharmacological inhibitors to investigate the role of sodium/hydrogen exchange proteins (Nhe) in Na(+) uptake in rainbow trout (Oncorhynchus mykiss) reared from fertilization in soft water (0.1mM Na(+)). For comparison, a second group of embryos/larvae reared in hard water (2.2mM Na(+), higher pH and [Ca(2+)]) were also included in the experiment but were fluxed in soft water, only. Unidirectional rates of Na(+) uptake increased throughout development and were significantly higher in embryos/larvae reared in soft water. However, the mechanisms of Na(+) uptake in both groups of larvae were not significantly different, either in larvae immediately post-hatch or later in development: the broad spectrum Na(+) channel blocker amiloride inhibited 85-90% of uptake and the Nhe-inhibitor EIPA also caused near maximal inhibitions of Na(+) uptake. These data indicated Na(+) uptake was Nhe-mediated in soft water. A role of Nhe3b (but not Nhe2 or Nhe3a) in Na(+) uptake in soft water was also supported through gene expression analyses: expression of nhe3b increased throughout development in whole embryos/larvae in both groups and was significantly higher in those reared in soft water. This pattern of expression correlated well with measurements of Na(+) uptake. Together these data indicate that in part, rainbow trout embryos/larvae reared in low Na(+) soft water maintained Na(+) homeostasis by an EIPA sensitive component of Na(+) uptake, and support a primary role for Nhe3b.
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Affiliation(s)
- David Boyle
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, T6G 2E9, Canada
| | - Salvatore D Blair
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, T6G 2E9, Canada
| | - Danuta Chamot
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, T6G 2E9, Canada
| | - Greg G Goss
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, T6G 2E9, Canada.
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16
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Zimmer AM, Wood CM. Physiological and molecular ontogeny of branchial and extra-branchial urea excretion in posthatch rainbow trout (Oncorhynchus mykiss). Am J Physiol Regul Integr Comp Physiol 2016; 310:R305-12. [PMID: 26608657 PMCID: PMC4796753 DOI: 10.1152/ajpregu.00403.2015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 11/24/2015] [Indexed: 12/31/2022]
Abstract
All teleost fish produce ammonia as a metabolic waste product. In embryos, ammonia excretion is limited by the chorion, and fish must detoxify ammonia by synthesizing urea via the ornithine urea cycle (OUC). Although urea is produced by embryos and larvae, urea excretion (J(urea)) is typically low until yolk sac absorption, increasing thereafter. The aim of this study was to determine the physiological and molecular characteristics of J(urea) by posthatch rainbow trout (Oncorhynchus mykiss). Following hatch, whole body urea concentration decreased over time, while J(urea) increased following yolk sac absorption. From 12 to 40 days posthatch (dph), extra-branchial routes of excretion accounted for the majority of J(urea), while the gills became the dominant site for J(urea) only after 55 dph. This represents the most delayed branchial ontogeny of any process studied to date. Urea transporter (UT) gene expression in the gills and skin increased over development, consistent with increases in branchial and extra-branchial J(urea). Following exposure to 25 mmol/l urea, the accumulation and subsequent elimination of exogenous urea was much greater at 55 dph than 12 dph, consistent with increased UT expression. Notably, UT gene expression in the gills of 55 dph larvae increased in response to high urea. In summary, there is a clear increase in urea transport capacity over posthatch development, despite a decrease in OUC activity.
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Affiliation(s)
- Alex M Zimmer
- Department of Biology, McMaster University, Hamilton, Ontario, Canada; and Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Chris M Wood
- Department of Biology, McMaster University, Hamilton, Ontario, Canada; and Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
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17
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Zimmer AM, Wilson JM, Wright PA, Hiroi J, Wood CM. Different mechanisms of Na+ uptake and ammonia excretion by the gill and yolk sac epithelium of early life stage rainbow trout. J Exp Biol 2016; 220:775-786. [DOI: 10.1242/jeb.148429] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 12/07/2016] [Indexed: 12/30/2022]
Abstract
In rainbow trout, the dominant site of Na+ uptake (JNain) and ammonia excretion (Jamm) shifts from the skin to the gills over development. Post-hatch (PH; 7 days post-hatch) larvae utilize the yolk sac skin for physiological exchange, whereas by complete yolk sac absorption (CYA; 30 days post-hatch), the gill is the dominant site. At the gills, JNain and Jamm occur via loose Na+/NH4+ exchange, but this exchange has not been examined in the skin of larval trout. Based on previous work, we hypothesized that, contrary to the gill model, JNain by the yolk sac skin of PH trout occurs independently of Jamm. Following a 12-h exposure to high environmental ammonia (HEA; 0.5 mmol l−1 NH4HCO3; [Na+]=600 µmol l−1; pH=8), Jamm by the gills of CYA trout and the yolk sac skin of PH larvae, which were isolated using divided chambers, increased significantly. However, this was coupled to an increase in JNain across the gills only, supporting our hypothesis. Moreover, gene expression of proteins involved in JNain (Na+/H+-exchanger-2 (NHE2) and H+-ATPase) increased in response to HEA only in the CYA gills. We further identified expression of the apical Rhesus (Rh) proteins Rhcg2 in putative pavement cells and Rhcg1 (co-localized with apical NHE2 and NHE3b and Na+/K+-ATPase) in putative peanut lectin agglutinin-positive (PNA+) ionocytes in gill sections. Similar Na+/K+-ATPase-positive cells expressing Rhcg1 and NHE3b, but not NHE2, were identified in the yolk sac epithelium. Overall, our findings suggest that the mechanisms of JNain and Jamm by the dominant exchange epithelium at two distinct stages of early development are fundamentally different.
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Affiliation(s)
- Alex M. Zimmer
- Department of Biology, University of Ottawa, Ottawa, ON, Canada K1N 6N57
- Department of Biology, Wilfrid Laurier University, ON, Canada N2L 3C5
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
| | | | - Patricia A. Wright
- Department of Anatomy, St Marianna University School of Medicine, Miyamae, Kawasaki 216-8511, Japan
| | - Junya Hiroi
- 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
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18
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Clifford AM, Zimmer AM, Wood CM, Goss GG. It's all in the gills: Evaluation of O2 uptake in Pacific hagfish refutes a major respiratory role for the skin. J Exp Biol 2016; 219:2814-2818. [DOI: 10.1242/jeb.141598] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 07/01/2016] [Indexed: 01/02/2023]
Abstract
Hagfish skin has been reported as an important site for ammonia excretion and as the major site of systemic oxygen acquisition. However, debate remains whether cutaneous O2 uptake is the dominant route of uptake; all evidence supporting this hypothesis has been derived using indirect measurements. Here we use separating chambers and direct measurements of oxygen consumption and ammonia excretion to quantify cutaneous and branchial exchanges in Pacific hagfish (Eptatretus stoutii) at rest and following exhaustive exercise. Hagfish primarily relied on the gills for both O2 uptake (81.0%) and ammonia excretion (70.7%). Following exercise, both O2 uptake and ammonia excretion increased, but only across the gill; cutaneous exchange was not increased. When branchial O2 availability was reduced by exposure to anteriorly-localized hypoxia (∼4.6 kPa O2), cutaneous O2 consumption was only slightly elevated on an absolute basis. These results refute a major role for cutaneous O2 acquisition in the Pacific hagfish.
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Affiliation(s)
- Alexander M. Clifford
- Department of Biological Sciences, University of Alberta, 116 St. and 85 Ave., Edmonton, Alberta, T6G 2R3, Canada
- Bamfield Marine Sciences Centre, 100 Pachena Rd., Bamfield, British Columbia, V0R 1B0, Canada
| | - Alex M. Zimmer
- Bamfield Marine Sciences Centre, 100 Pachena Rd., Bamfield, British Columbia, V0R 1B0, Canada
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, V6T 1Z4, Canada
| | - Chris M. Wood
- Bamfield Marine Sciences Centre, 100 Pachena Rd., Bamfield, British Columbia, V0R 1B0, Canada
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, V6T 1Z4, Canada
| | - Greg G. Goss
- Department of Biological Sciences, University of Alberta, 116 St. and 85 Ave., Edmonton, Alberta, T6G 2R3, Canada
- Bamfield Marine Sciences Centre, 100 Pachena Rd., Bamfield, British Columbia, V0R 1B0, Canada
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19
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Zimmer AM, Wright PA, Wood CM. What is the primary function of the early teleost gill? Evidence for Na+/NH+4 exchange in developing rainbow trout (Oncorhynchus mykiss). Proc Biol Sci 2015; 281:rspb.2014.1422. [PMID: 25274361 DOI: 10.1098/rspb.2014.1422] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Post-hatch fishes lack a functional gill and use cutaneous surfaces for exchange with the surrounding environment. The ionoregulatory hypothesis posits that ionoregulation is the first physiological process to be limited by cutaneous exchange, necessitating its shift to the gills. We hypothesized that the ontogeny of branchial ammonia excretion (J amm) is coupled to Na(+) uptake (J Na in) in accordance with the current model for Na+/NH4+ in exchange in freshwater. Using divided chambers, branchial and cutaneous J amm, J Na in and oxygen consumption (MO2) by larval rainbow trout were assessed. Following hatch, the skin accounted for 97% and 86% of total J amm and J Na in, respectively. J amm and J Na in shifted to the gills simultaneously at 15 days post-hatch (dph) and were highly correlated (R(2) = 0.951) at the gills, but not the skin, over development. Contrastingly, MO2 shifted significantly later at 27 dph, in agreement with the ionoregulatory hypothesis. Moreover, the mRNA expression and/or enzymatic activity of Rhesus proteins, Na(+)/H(+)-exchanger, H(+)-ATPase, Na(+)/K(+)-ATPase and carbonic anhydrase, all key components of the Na+/NH4+-exchange system, increased in the gills over larval development. We propose that the ontogeny of branchial J Na in occurs as Na+/NH4+ exchange and provide evidence for a novel element to the ionoregulatory hypothesis, the excretion of potentially lethal metabolic ammonia.
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Affiliation(s)
- Alex M Zimmer
- Department of Biology, McMaster University, Hamilton, Ontario, Canada L8S 4K1
| | - Patricia A Wright
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
| | - Chris M Wood
- Department of Biology, McMaster University, Hamilton, Ontario, Canada L8S 4K1
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20
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Lawrence MJ, Wright PA, Wood CM. Physiological and molecular responses of the goldfish (Carassius auratus) kidney to metabolic acidosis, and potential mechanisms of renal ammonia transport. ACTA ACUST UNITED AC 2015; 218:2124-35. [PMID: 25987732 DOI: 10.1242/jeb.117689] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 05/05/2015] [Indexed: 01/20/2023]
Abstract
Relative to the gills, the mechanisms by which the kidney contributes to ammonia and acid-base homeostasis in fish are poorly understood. Goldfish were exposed to a low pH environment (pH 4.0, 48 h), which induced a characteristic metabolic acidosis and an increase in total plasma [ammonia] but reduced plasma ammonia partial pressure (PNH3). In the kidney tissue, total ammonia, lactate and intracellular pH remained unchanged. The urinary excretion rate of net base under control conditions changed to net acid excretion under low pH, with contributions from both the NH4 (+) (∼30%) and titratable acidity minus bicarbonate (∼70%; TA-HCO3 (-)) components. Inorganic phosphate (Pi), urea and Na(+) excretion rates were also elevated while Cl(-) excretion rates were unchanged. Renal alanine aminotransferase activity increased under acidosis. The increase in renal ammonia excretion was due to significant increases in both the glomerular filtration and the tubular secretion rates of ammonia, with the latter accounting for ∼75% of the increase. There was also a 3.5-fold increase in the mRNA expression of renal Rhcg-b (Rhcg1) mRNA. There was no relationship between ammonia secretion and Na(+) reabsorption. These data indicate that increased renal ammonia secretion during acidosis is probably mediated through Rhesus (Rh) glycoproteins and occurs independently of Na(+) transport, in contrast to branchial and epidermal models of Na(+)-dependent ammonia transport in freshwater fish. Rather, we propose a model of parallel H(+)/NH3 transport as the primary mechanism of renal tubular ammonia secretion that is dependent on renal amino acid catabolism.
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Affiliation(s)
- Michael J Lawrence
- Department of Biology, McMaster University, Hamilton, ON, Canada L8S 4K1 Department of Biology, Carleton University, Ottawa, ON, Canada K1S 5B6
| | - Patricia A Wright
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada N1G 2W1
| | - Chris M Wood
- Department of Biology, McMaster University, Hamilton, ON, Canada L8S 4K1 Department of Zoology, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
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21
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Kumai Y, Harris J, Al-Rewashdy H, Kwong RWM, Perry SF. Nitrogenous Waste Handling by Larval Zebrafish Danio rerio in Alkaline Water. Physiol Biochem Zool 2015; 88:137-45. [DOI: 10.1086/679628] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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22
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Thompson WA, Rodela TM, Richards JG. The effects of strain and ploidy on the physiological responses of rainbow trout (Oncorhynchus mykiss) to pH 9.5 exposure. Comp Biochem Physiol B Biochem Mol Biol 2014; 183:22-9. [PMID: 25541222 DOI: 10.1016/j.cbpb.2014.12.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Revised: 12/15/2014] [Accepted: 12/16/2014] [Indexed: 11/30/2022]
Abstract
We characterized the physiological effects of exposure to pH9.5 on one domesticated and four wild strains of diploid and triploid juvenile rainbow trout (Oncorhynchus mykiss) over two consecutive years. In the first year, 35-70% of the individuals from the wild strains showed a loss of equilibrium (LOE) at 12 h exposure to pH9.5, with all fish from wild strains experiencing a LOE by 48 h. In contrast, <20% of the domesticated strain showed LOE over the 48 h exposure to pH9.5. In our second experiment, similar strain effects were observed, but far fewer fish showed LOE (≤50% in all strains) over 72 h at pH9.5. In both experiments, there was no effect of ploidy on time to LOE. In the fish that did not show LOE, high pH exposure resulted in significant increases in plasma, brain and muscle ammonia, with no effect of strain or ploidy on the extent of ammonia accumulation. Glutamine accumulated in the brain during high pH exposure, with a stoichiometric decrease in glutamate, but no differences were noted among strains or ploidies. Lactate also accumulated in the plasma to a similar extent in all trout strains and ploidies. Plasma chloride decreased at 24h exposure in all trout strains and ploidies, but recovered by 72 h. No change was observed in plasma sodium. Overall, our data suggest that the domesticated strain of trout is more tolerant of pH9.5 than the wild strains, but these differences in tolerance cannot be explained by our sub-lethal assessment of ammonia balance or ion regulation.
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Affiliation(s)
- William A Thompson
- Department of Zoology, The University of British Columbia, 6270 University Blvd., Vancouver, BC V6T 1Z4, Canada.
| | - Tamara M Rodela
- Department of Zoology, The University of British Columbia, 6270 University Blvd., Vancouver, BC V6T 1Z4, Canada
| | - Jeffrey G Richards
- Department of Zoology, The University of British Columbia, 6270 University Blvd., Vancouver, BC V6T 1Z4, Canada
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23
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Rubino JG, Zimmer AM, Wood CM. Intestinal ammonia transport in freshwater and seawater acclimated rainbow trout (Oncorhynchus mykiss): evidence for a Na+ coupled uptake mechanism. Comp Biochem Physiol A Mol Integr Physiol 2014; 183:45-56. [PMID: 25545914 DOI: 10.1016/j.cbpa.2014.12.037] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2014] [Revised: 12/17/2014] [Accepted: 12/19/2014] [Indexed: 12/23/2022]
Abstract
In vitro gut sac experiments were performed on freshwater and 60% seawater acclimated trout (Oncorhynchus mykiss) under treatments designed to discern possible mechanisms of intestinal ammonia transport. Seawater acclimation increased ammonia flux rate into the serosal saline (Jsamm) in the anterior intestine, however it did not alter Jsamm in the mid- or posterior intestine suggesting similar mechanisms of ammonia handling in freshwater and seawater fish. Both fluid transport rate (FTR) and Jsamm were inhibited in response to basolateral ouabain treatment, suggesting a linkage of ammonia uptake to active transport, possibly coupled to fluid transport processes via solvent drag. Furthermore, decreases in FTR and Jsamm caused by low Na(+) treatment indicated a Na(+) linked transport mechanism. Mucosal bumetanide (10(-4) M) had no impact on FTR, yet decreased Jsamm in the anterior and mid-intestine, suggesting NH4(+) substitution for K(+) on an apical NKCC, and at least a partial uncoupling of ammonia transport from fluid transport. Additional treatments (amiloride, 5-(N-ethyl-N-isopropyl)amiloride (EIPA), phenamil, bafilomycin, 4',6-diamidino-2-phenylindole (DAPI), high sodium) intended to disrupt alternative routes of Na(+) uptake yielded no change in FTR or Jsamm, suggesting the absence of direct competition between Na(+) and ammonia for transport. Finally, [(14)C]methylamine permeability (PMA) measurements indicated the likely presence of an intestinal Rh-mediated ammonia transport system, as increasing NH4Cl (0, 1, 5 mmol l(-1)) concentrations reduced PMA, suggesting competition for transport through Rh proteins. Overall, the data presented in this paper provide some of the first insights into mechanisms of teleost intestinal ammonia transport.
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Affiliation(s)
- Julian G Rubino
- McMaster University, Life Sciences Building, Department of Biology, Hamilton, Ontario L8S 4K1, Canada; Bamfield Marine Sciences Centre, Bamfield, British Columbia V0R 1B0, Canada.
| | - Alex M Zimmer
- McMaster University, Life Sciences Building, Department of Biology, Hamilton, Ontario L8S 4K1, Canada; Bamfield Marine Sciences Centre, Bamfield, British Columbia V0R 1B0, Canada
| | - Chris M Wood
- McMaster University, Life Sciences Building, Department of Biology, Hamilton, Ontario L8S 4K1, Canada; Bamfield Marine Sciences Centre, Bamfield, British Columbia V0R 1B0, Canada; Dept. of Zoology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
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