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Yamaguchi Y, Ikeba K, Yoshida MA, Takagi W. Molecular basis of the unique osmoregulatory strategy in the inshore hagfish, Eptatretus burgeri. Am J Physiol Regul Integr Comp Physiol 2024; 327:R208-R233. [PMID: 38105762 DOI: 10.1152/ajpregu.00166.2023] [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: 07/03/2023] [Revised: 12/05/2023] [Accepted: 12/11/2023] [Indexed: 12/19/2023]
Abstract
Hagfishes are characterized by omo- and iono-conforming nature similar to marine invertebrates. Conventionally, hagfishes had been recognized as the most primitive living vertebrate that retains plesiomorphic features. However, some of the "ancestral" features of hagfishes, such as rudimentary eyes and the lack of vertebrae, have been proven to be deceptive. Similarly, by the principle of maximum parsimony, the unique body fluid regulatory strategy of hagfishes seems to be apomorphic, since the lamprey, another cyclostome, adopts osmo- and iono-regulatory mechanisms as in jawed vertebrates. Although hagfishes are unequivocally important in discussing the origin and evolution of the vertebrate osmoregulatory system, the molecular basis for the body fluid homeostasis in hagfishes has been poorly understood. In the present study, we explored this matter in the inshore hagfish, Eptatretus burgeri, by analyzing the transcriptomes obtained from the gill, kidney, and muscle of the animals acclimated to distinct environmental salinities. Together with the measurement of parameters in the muscular fluid compartment, our data indicate that the hagfish possesses an ability to conduct free amino acid (FAA)-based osmoregulation at a cellular level, which is in coordination with the renal and branchial FAA absorption. We also revealed that the hagfish does possess the orthologs of the known osmoregulatory genes and that the transepithelial movement of inorganic ions in the hagfish gill and kidney is more complex than previously thought. These observations pose a challenge to the conventional view that the physiological features of hagfishes have been inherited from the last common ancestor of the extant vertebrates.
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Affiliation(s)
- Yoko Yamaguchi
- Institute of Agricultural and Life Sciences, Academic Assembly, Shimane University, Matsue, Japan
| | - Kiriko Ikeba
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Japan
| | - Masa-Aki Yoshida
- Institute of Agricultural and Life Sciences, Academic Assembly, Shimane University, Matsue, Japan
- Marine Biological Science Section, Education and Research Center for Biological Resources, Faculty of Life and Environmental Science, Shimane University, Okinoshima, Japan
| | - Wataru Takagi
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Japan
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Brownstein CD, Near TJ. Colonization of the ocean floor by jawless vertebrates across three mass extinctions. BMC Ecol Evol 2024; 24:79. [PMID: 38867201 PMCID: PMC11170801 DOI: 10.1186/s12862-024-02253-y] [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: 01/16/2024] [Accepted: 05/07/2024] [Indexed: 06/14/2024] Open
Abstract
BACKGROUND The deep (> 200 m) ocean floor is often considered to be a refugium of biodiversity; many benthic marine animals appear to share ancient common ancestry with nearshore and terrestrial relatives. Whether this pattern holds for vertebrates is obscured by a poor understanding of the evolutionary history of the oldest marine vertebrate clades. Hagfishes are jawless vertebrates that are either the living sister to all vertebrates or form a clade with lampreys, the only other surviving jawless fishes. RESULTS We use the hagfish fossil record and molecular data for all recognized genera to construct a novel hypothesis for hagfish relationships and diversification. We find that crown hagfishes persisted through three mass extinctions after appearing in the Permian ~ 275 Ma, making them one of the oldest living vertebrate lineages. In contrast to most other deep marine vertebrates, we consistently infer a deep origin of continental slope occupation by hagfishes that dates to the Paleozoic. Yet, we show that hagfishes have experienced marked body size diversification over the last hundred million years, contrasting with a view of this clade as morphologically stagnant. CONCLUSION Our results establish hagfishes as ancient members of demersal continental slope faunas and suggest a prolonged accumulation of deep sea jawless vertebrate biodiversity.
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Affiliation(s)
- Chase Doran Brownstein
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, 06511, USA.
| | - Thomas J Near
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, 06511, USA
- Yale Peabody Museum, Yale University, New Haven, CT, 06511, USA
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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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4
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Giacomin M, Drummond JM, Supuran CT, Goss GG. The roles of plasma accessible and cytosolic carbonic anhydrases in bicarbonate (HCO 3-) excretion in Pacific hagfish (Eptatretus stoutii). J Comp Physiol B 2022; 192:713-725. [PMID: 36098803 DOI: 10.1007/s00360-022-01459-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Revised: 08/08/2022] [Accepted: 08/23/2022] [Indexed: 11/29/2022]
Abstract
Pacific hagfish (Eptatretus stoutii) are marine scavengers and feed on decaying animal carrion by burrowing their bodies inside rotten carcasses where they are exposed to several threatening environmental stressors, including hypercapnia (high partial pressures of CO2). Hagfish possess a remarkable capacity to tolerate hypercapnia, and their ability to recover from acid-base disturbances is well known. To deal with the metabolic acidosis resulting from exposure to high CO2, hagfish can mount a rapid elevation of plasma HCO3- concentration (hypercarbia). Once PCO2 is restored, hagfish quickly excrete their HCO3- load, a process that likely involves the enzyme carbonic anhydrase (CA), which catalyzes HCO3- dehydration into CO2 at the hagfish gills. We aimed to characterize the role of branchial CA in CO2/HCO3- clearance from the plasma at the gills of E. stoutii, under control and high PCO2 (hypercapnic) exposure conditions. We assessed the relative contributions of plasma accessible versus intracellular (cytosolic) CA to gill HCO3- excretion by measuring in situ [14C]-HCO3- fluxes. To accomplish this, we employed a novel surgical technique of individual gill pouch arterial perfusion combined with perifusion of the gill afferent to efferent water ducts. [14C]-HCO3- efflux was measured at the gills of fish exposed to control, hypercapnic (48 h) and recovery from hypercapnia conditions (6 h), in the presence of two well-known pharmacological inhibitors of CA, the membrane impermeant C18 (targets membrane bound, plasma accessible CA) and membrane-permeant acetazolamide, which targets all forms of CA, including extracellular and intracellular cytosolic CAs. C18 did not affect HCO3- flux in control fish, whereas acetazolamide resulted in a significant reduction of 72%. In hypercapnic fish, HCO3- fluxes were much higher and perfusion with acetazolamide caused a reduction of HCO3- flux by 38%. The same pattern was observed for fish in recovery, where in all three experimental conditions, there was no significant inhibition of plasma-accessible CA. We also observed no change in CA enzyme activity (measured in vitro) in any of the experimental PCO2 conditions. In summary, our data suggests that there are additional pathways for HCO3- excretion at the gills of hagfish that are independent of plasma-accessible CA.
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Affiliation(s)
- Marina Giacomin
- Department of Biological Sciences, University of Alberta, CW 405, Biological Sciences Bldg., Edmonton, AB, T6G 2E9, Canada. .,Bamfield Marine Science Centre, Bamfield, BC, V0R 1B0, Canada.
| | - Jenna M Drummond
- Department of Biological Sciences, University of Alberta, CW 405, Biological Sciences Bldg., Edmonton, AB, T6G 2E9, Canada.,Bamfield Marine Science Centre, Bamfield, BC, V0R 1B0, Canada
| | - Claudiu T Supuran
- Neurofarba Department, University of Florence, Via Ugo Schiff 6, Florence, Italy
| | - Greg G Goss
- Department of Biological Sciences, University of Alberta, CW 405, Biological Sciences Bldg., Edmonton, AB, T6G 2E9, Canada.,Bamfield Marine Science Centre, Bamfield, BC, V0R 1B0, Canada
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Birceanu O, Ferreira P, Neal J, Sunga J, Anthony S, Davidson S, Edwards SL, Wilson JM, Youson JH, Vijayan MM, Wilkie MP. Divergent pathways of ammonia and urea production and excretion during the life cycle of the sea lamprey. Physiol Biochem Zool 2022; 95:551-567. [DOI: 10.1086/721606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Guo H, Lin W, Wu X, Wang L, Zhang D, Li L, Li D, Tang R, Yang L, Qiu Y. Survival strategies of Wuchang bream (Megalobrama amblycephala) juveniles for chronic ammonia exposure: Antioxidant defense and the synthesis of urea and glutamine. Comp Biochem Physiol C Toxicol Pharmacol 2020; 230:108707. [PMID: 31953219 DOI: 10.1016/j.cbpc.2020.108707] [Citation(s) in RCA: 4] [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: 10/13/2019] [Revised: 12/20/2019] [Accepted: 01/11/2020] [Indexed: 12/19/2022]
Abstract
This study aimed to explore how Wuchang bream (Megalobrama amblycephala) survive and defend against the toxicity of ambient total ammonia nitrogen (0, 5, 10, 20 and 30 mg/L TA-N) during 30-day exposure. As a result, hepatic malondialdehyde and protein carbonylation as well as histopathological alterations increased with increasing TA-N level, which suggested that chronic ammonia exposure caused oxidative stress and damage in the liver of fish. Meanwhile, the activities of hepatic total superoxide dismutase (T-SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR) and glucose 6-phosphate dehydrogenase (G6PD) as well as the mRNA expression of Cu/Zn sod, cat, gpx and g6pd were elevated significantly along with significant reduction of glutathione (GSH) and nicotinamide adenine dinucleotide phosphate (NADPH) (P < 0.05). These results indicated that hepatic antioxidant responses were activated to alleviate oxidative damages induced by ammonia, in which lower-concentration ammonia only initiate SOD-CAT-GR-G6PDH defense and higher ammonia activated the SOD-CAT-GPx-GSH-GR-G6PDH antioxidant response. In addition, significant increases of serum urea and hepatic ammonia, urea, glutamine, arginase as well as glutamine synthetase were detected with the increase of TA-N (P < 0.05), while serum ammonia levels kept stable (P > 0.05). The present findings further revealed that ammonia could be detoxified directly into glutamine and urea in Wuchang bream to cope with ammonia exposure. In conclusion, under chronic ammonia exposure, enhanced hepatic antioxidant responses as well as increased urea and glutamine synthesis worked in combination to allow Megalobrama amblycephala to defend against environmental ammonia toxicity.
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Affiliation(s)
- Honghui Guo
- College of Fisheries, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Wang Lin
- College of Fisheries, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Xueyang Wu
- College of Fisheries, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Lingkai Wang
- College of Fisheries, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Dandan Zhang
- College of Fisheries, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Li Li
- College of Fisheries, Huazhong Agricultural University, Wuhan 430070, PR China; Hubei Provincial Engineering Laboratory for Pond Aquaculture, Wuhan 430070, PR China; National Demonstration Center for Experimental Aquaculture Education (Huazhong Agricultural University), Wuhan 430070, PR China.
| | - Dapeng Li
- College of Fisheries, Huazhong Agricultural University, Wuhan 430070, PR China; Hubei Provincial Engineering Laboratory for Pond Aquaculture, Wuhan 430070, PR China; National Demonstration Center for Experimental Aquaculture Education (Huazhong Agricultural University), Wuhan 430070, PR China
| | - Rong Tang
- College of Fisheries, Huazhong Agricultural University, Wuhan 430070, PR China; Hubei Provincial Engineering Laboratory for Pond Aquaculture, Wuhan 430070, PR China; National Demonstration Center for Experimental Aquaculture Education (Huazhong Agricultural University), Wuhan 430070, PR China
| | - Liping Yang
- College of Fisheries, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Yuming Qiu
- College of Fisheries, Huazhong Agricultural University, Wuhan 430070, PR China
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7
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Durant AC, Donini A. Development of Aedes aegypti (Diptera: Culicidae) mosquito larvae in high ammonia sewage in septic tanks causes alterations in ammonia excretion, ammonia transporter expression, and osmoregulation. Sci Rep 2019; 9:19028. [PMID: 31836747 PMCID: PMC6911005 DOI: 10.1038/s41598-019-54413-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 11/12/2019] [Indexed: 12/18/2022] Open
Abstract
Larvae of the disease vector mosquito, Aedes aegypti (L.) readily develop in ammonia rich sewage in the British Virgin Islands. To understand how the larvae survive in ammonia levels that are lethal to most animals, an examination of ammonia excretory physiology in larvae collected from septic-water and freshwater was carried out. A. aegypti larvae were found to be remarkably plastic in dealing with high external ammonia through the modulation of NH4+ excretion at the anal papillae, measured using the scanning ion-selective electrode technique (SIET), and NH4+ secretion in the primary urine by the Malpighian tubules when developing in septicwater. Ammonia transporters, Amt and Rh proteins, are expressed in ionoregulatory and excretory organs, with increases in Rh protein, Na+-K+-ATPase, and V-type-H+-ATPase expression observed in the Malpighian tubules, hindgut, and anal papillae in septic-water larvae. A comparative approach using laboratory A. aegypti larvae reared in high ammonia septic-water revealed similar responses to collected A. aegypti with regard to altered ammonia secretion and hemolymph ion composition. Results suggest that the observed alterations in excretory physiology of larvae developing in septic-water is a consequence of the high ammonia levels and that A. aegypti larvae may rely on ammonia transporting proteins coupled to active transport to survive in septic-water.
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Affiliation(s)
- Andrea C Durant
- Department of Biology, York University, Toronto, Ontario, Canada.
| | - Andrew Donini
- Department of Biology, York University, Toronto, Ontario, Canada
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8
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Eom J, Giacomin M, Clifford AM, Goss GG, Wood CM. Ventilatory sensitivity to ammonia in the Pacific hagfish ( Eptatretus stoutii), a representative of the oldest extant connection to the ancestral vertebrates. ACTA ACUST UNITED AC 2019; 222:jeb.199794. [PMID: 31221739 DOI: 10.1242/jeb.199794] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Accepted: 06/16/2019] [Indexed: 12/30/2022]
Abstract
Ventilatory sensitivity to ammonia occurs in teleosts, elasmobranchs and mammals. Here, we investigated whether the response is also present in hagfish. Ventilatory parameters (nostril flow, pressure amplitude, velar frequency and ventilatory index, the last representing the product of pressure amplitude and frequency), together with blood and water chemistry, were measured in hagfish exposed to either high environmental ammonia (HEA) in the external sea water or internal ammonia loading by intra-vascular injection. HEA exposure (10 mmol l-1 NH4HCO3 or 10 mmol l-1 NH4Cl) caused a persistent hyperventilation by 3 h, but further detailed analysis of the NH4HCO3 response showed that initially (within 5 min) there was a marked decrease in ventilation (80% reduction in ventilatory index and nostril flow), followed by a later 3-fold increase, by which time plasma total ammonia concentration had increased 11-fold. Thus, hyperventilation in HEA appeared to be an indirect response to internal ammonia elevation, rather than a direct response to external ammonia. HEA-mediated increases in oxygen consumption also occurred. Responses to NH4HCO3 were greater than those to NH4Cl, reflecting greater increases over time in water pH and P NH3 in the former. Hagfish also exhibited hyperventilation in response to direct injection of isotonic NH4HCO3 or NH4Cl solutions into the caudal sinus. In all cases where hyperventilation occurred, plasma total ammonia and P NH3 levels increased significantly, while blood acid-base status remained unchanged, indicating specific responses to internal ammonia elevation. The sensitivity of breathing to ammonia arose very early in vertebrate evolution.
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Affiliation(s)
- Junho Eom
- Bamfield Marine Sciences Centre, 100 Pachena Road, Bamfield, BC, Canada V0R 1B0 .,Department of Zoology, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
| | - Marina Giacomin
- Bamfield Marine Sciences Centre, 100 Pachena Road, Bamfield, BC, Canada V0R 1B0.,Department of Zoology, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
| | - Alexander M Clifford
- Bamfield Marine Sciences Centre, 100 Pachena Road, Bamfield, BC, Canada V0R 1B0.,Department of Zoology, University of British Columbia, Vancouver, BC, Canada V6T 1Z4.,Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada T6G 2E9
| | - Greg G Goss
- Bamfield Marine Sciences Centre, 100 Pachena Road, Bamfield, BC, Canada V0R 1B0.,Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada T6G 2E9
| | - Chris M Wood
- Bamfield Marine Sciences Centre, 100 Pachena Road, Bamfield, BC, Canada V0R 1B0.,Department of Zoology, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
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Giacomin M, Dal Pont G, Eom J, Schulte PM, Wood CM. The effects of salinity and hypoxia exposure on oxygen consumption, ventilation, diffusive water exchange and ionoregulation in the Pacific hagfish (Eptatretus stoutii). Comp Biochem Physiol A Mol Integr Physiol 2019; 232:47-59. [PMID: 30878760 DOI: 10.1016/j.cbpa.2019.03.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 01/30/2019] [Accepted: 03/06/2019] [Indexed: 10/27/2022]
Abstract
Hagfishes (Class: Myxini) are marine jawless craniate fishes that are widely considered to be osmoconformers whose plasma [Na+], [Cl-] and osmolality closely resemble that of sea water, although they have the ability to regulate plasma [Ca2+] and [Mg2+] below seawater levels. We investigated the responses of Pacific hagfish to changes in respiratory and ionoregulatory demands imposed by a 48-h exposure to altered salinity (25 ppt, 30 ppt (control) and 35 ppt) and by an acute hypoxia exposure (30 Torr; 4 kPa). When hagfish were exposed to 25 ppt, oxygen consumption rate (MO2), ammonia excretion rate (Jamm) and unidirectional diffusive water flux rate (JH2O, measured with 3H2O) were all reduced, pointing to an interaction between ionoregulation and gas exchange. At 35 ppt, JH2O was reduced, though MO2 and Jamm did not change. As salinity increased, so did the difference between plasma and external water [Ca2+] and [Mg2+]. Notably, the same pattern was seen for plasma Cl-, which was kept below seawater [Cl-] at all salinities, while plasma [Na+] was regulated well above seawater [Na+], but plasma osmolality matched seawater values. MO2 was reduced by 49% and JH2O by 36% during hypoxia, despite a small elevation in overall ventilation. Our results depart from the "classical" osmorespiratory compromise but are in accord with responses in other hypoxia-tolerant fish; instead of an exacerbation of gill fluxes when gas transfer is upregulated, the opposite happens.
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Affiliation(s)
- Marina Giacomin
- Department of Zoology, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Bamfield Marine Sciences Centre, Bamfield, British Columbia V0R 1B0, Canada.
| | - Giorgi Dal Pont
- Department of Zoology, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Bamfield Marine Sciences Centre, Bamfield, British Columbia V0R 1B0, Canada; Integrated Group for Aquaculture and Environmental Studies, Department of Animal Science, Federal University of Paraná, Curitiba, Paraná 83035-050, Brazil
| | - Junho Eom
- Department of Zoology, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Bamfield Marine Sciences Centre, Bamfield, British Columbia V0R 1B0, Canada.
| | - Patricia M Schulte
- Department of Zoology, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada.
| | - Chris M Wood
- Department of Zoology, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Bamfield Marine Sciences Centre, Bamfield, British Columbia V0R 1B0, Canada; Department of Biology, McMaster University, Hamilton, Ontario L8S 4K1, Canada.
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10
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Giacomin M, Eom J, Schulte PM, Wood CM. Acute temperature effects on metabolic rate, ventilation, diffusive water exchange, osmoregulation, and acid–base status in the Pacific hagfish (Eptatretus stoutii). J Comp Physiol B 2018; 189:17-35. [DOI: 10.1007/s00360-018-1191-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 10/30/2018] [Accepted: 11/05/2018] [Indexed: 12/21/2022]
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11
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Clifford AM, Weinrauch AM, Goss GG. Dropping the base: recovery from extreme hypercarbia in the CO2 tolerant Pacific hagfish (Eptatretus stoutii). J Comp Physiol B 2017; 188:421-435. [PMID: 29290001 DOI: 10.1007/s00360-017-1141-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2017] [Revised: 11/24/2017] [Accepted: 12/12/2017] [Indexed: 01/13/2023]
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12
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Weinrauch AM, Clifford AM, Goss GG. Functional redundancy of glucose acquisition mechanisms in the hindgut of Pacific hagfish (Eptatretus stoutii). Comp Biochem Physiol A Mol Integr Physiol 2017; 216:8-13. [PMID: 29126986 DOI: 10.1016/j.cbpa.2017.10.034] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 10/26/2017] [Accepted: 10/31/2017] [Indexed: 02/09/2023]
Abstract
This study examined the mechanisms of glucose acquisition in the hindgut of Pacific hagfish (Eptatretus stoutii) using in vitro gut sac techniques. The intestine was determined to have the capacity to digest maltose into glucose along the entirety of the tract, including the foregut. Glucose uptake was biphasic and consisted of a high-affinity, low-capacity concentration-dependent component conforming to Michaelis-Menten kinetics (Km 0.37mM, Jmax 8.48nmol/cm2/h) as well as a diffusive component. There was no observed difference in glucose flux rate along the length of the intestine, similar to other nutrients investigated in the hagfish intestine. A reduced sodium (<1mM) environment did not result in a change in glucose uptake rates, likely due to a functional redundancy of glucose transporters. There was no observed effect of phloretin, yet the sodium glucose-linked transporter (SGLT)-specific inhibitor phlorizin significantly reduced glucose uptake at all concentrations tested (0.0001-1mM). Additionally, the glucose transporter (GLUT) inhibitor cytochalasin b significantly reduced glucose transport rates. The effects of these pharmacological inhibition experiments suggest the presence of multiple types of glucose transport proteins. This study clarifies the uptake strategies used by hagfish to acquire glucose at the intestine and provides insight into the evolution of such transport systems in early-diverging vertebrates.
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Affiliation(s)
- Alyssa M Weinrauch
- 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.
| | - 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
| | - 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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13
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Gilmour KM. Heads you gain, tails you lose. Am J Physiol Regul Integr Comp Physiol 2017; 313:R65-R66. [DOI: 10.1152/ajpregu.00208.2017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 06/03/2017] [Indexed: 11/22/2022]
Affiliation(s)
- K. M. Gilmour
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
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14
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Weinrauch AM, Clifford AM, Goss GG. Post-prandial physiology and intestinal morphology of the Pacific hagfish (Eptatretus stoutii). J Comp Physiol B 2017; 188:101-112. [DOI: 10.1007/s00360-017-1118-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 07/04/2017] [Accepted: 07/11/2017] [Indexed: 12/26/2022]
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Clifford AM, Bury NR, Schultz AG, Ede JD, Goss BL, Goss GG. Regulation of plasma glucose and sulfate excretion in Pacific hagfish, Eptatretus stoutii is not mediated by 11-deoxycortisol. Gen Comp Endocrinol 2017; 247:107-115. [PMID: 28126345 DOI: 10.1016/j.ygcen.2017.01.022] [Citation(s) in RCA: 7] [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: 04/27/2016] [Revised: 01/16/2017] [Accepted: 01/19/2017] [Indexed: 10/20/2022]
Abstract
The goal of this study was to identify whether Pacific hagfish (Eptatretus stoutii) possess glucocorticoid and mineralocorticoid responses and to examine the potential role(s) of four key steroids in these responses. Pacific hagfish were injected with varying amounts of cortisol, corticosterone or 11-deoxycorticosterone (DOC) using coconut oil implants and plasma glucose and gill total-ATPase activity were monitored as indices of glucocorticoid and mineralocorticoid responses. Furthermore, we also monitored plasma glucose and 11-deoxycortisol (11-DOC) levels following exhaustive stress (30 min of agitation) or following repeated infusion with SO42-. There were no changes in gill total-ATPase following implantation with any steroid, with only very small statistical increases in plasma glucose noted in hagfish implanted with either DOC (at 20 and 200mgkg-1 at 7 and 4days post-injection, respectively) or corticosterone (at 100mgkg-1 at 7days post-injection). Following exhaustive stress, hagfish displayed a large and sustained increase in plasma glucose. Repeated infusion of SO42- into hagfish caused increases in both plasma glucose levels and SO42- excretion rate suggesting a regulated glucocorticoid and mineralocorticoid response. However, animals under either condition did not show any significant increases in plasma 11-DOC concentrations. Our results suggest that while there are active glucocorticoid and mineralocorticoid responses in hagfish, 11-DOC does not appear to be involved and the identity and primary function of the steroid in hagfish remains to be elucidated.
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Affiliation(s)
- Alexander M Clifford
- Bamfield Marine Sciences Centre, Bamfield, BC, Canada; Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Nicolas R Bury
- Bamfield Marine Sciences Centre, Bamfield, BC, Canada; Diabetes & Nutritional Sciences Division, Kings College, London, UK; Faculty of Health and Life Sciences, University of Suffolk, Suffolk, UK
| | - Aaron G Schultz
- Bamfield Marine Sciences Centre, Bamfield, BC, Canada; Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - James D Ede
- Bamfield Marine Sciences Centre, Bamfield, BC, Canada; Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Brendan L Goss
- Bamfield Marine Sciences Centre, Bamfield, BC, Canada; Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Greg G Goss
- Bamfield Marine Sciences Centre, Bamfield, BC, Canada; Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada.
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16
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Gao N, Zhu L, Guo Z, Yi M, Zhang L. Effects of chronic ammonia exposure on ammonia metabolism and excretion in marine medaka Oryzias melastigma. FISH & SHELLFISH IMMUNOLOGY 2017; 65:226-234. [PMID: 28428060 DOI: 10.1016/j.fsi.2017.04.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 03/01/2017] [Accepted: 04/16/2017] [Indexed: 06/07/2023]
Abstract
Ammonia is highly toxic to aquatic organisms, but whether ammonia excretion or ammonia metabolism to less toxic compounds is the major strategy for detoxification in marine fish against chronic ammonia exposure is unclear to date. In this study, we investigated the metabolism and excretion of ammonia in marine medaka Oryzias melastigma during chronic ammonia exposure. The fish were exposed to 0, 0.1, 0.3, 0.6, and 1.1 mmol l-1 NH4Cl spiked seawater for 8 weeks. Exposure of 0.3-1.1 mmol l-1 NH4Cl had deleterious effects on the fish, including significant reductions in growth, feed intake, and total protein content. However, the fish could take strategies to detoxify ammonia. The tissue ammonia (TAmm) in the 0.3-1.1 mmol l-1 NH4Cl treatments was significantly higher than those in the 0 and 0.1 mmol l-1 NH4Cl treatments after 2 weeks of exposure, but it recovered with prolonged exposure time, ultimately reaching the control level after 8 weeks. The amino acid catabolic rate decreased to reduce the gross ammonia production with the increasing ambient ammonia concentration. The concentrations of most metabolites remained constant in the 0-0.6 mmol l-1 NH4Cl treatments, whereas 5 amino acids and 3 energy metabolism-related metabolites decreased in the 1.1 mmol l-1 NH4Cl treatment. JAmm steadily increased in ambient ammonia from 0 to 0.6 mmol l-1 and slightly decreased when the ambient ammonia concentration increased to 1.1 mmol l-1. Overall, marine medaka cope with sublethal ammonia environment by regulating the tissue TAmm via reducing the ammonia production and increasing ammonia excretion.
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Affiliation(s)
- Na Gao
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China; University of Chinese Academy Sciences, Beijing, 100049, China
| | - Limei Zhu
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China
| | - Zhiqiang Guo
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China
| | - Meisheng Yi
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Sun Yat-sen University, Guangzhou, Guangdong, China.
| | - Li Zhang
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China.
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17
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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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18
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Glover CN, Wood CM, Goss GG. Drinking and water permeability in the Pacific hagfish, Eptatretus stoutii. J Comp Physiol B 2017; 187:1127-1135. [DOI: 10.1007/s00360-017-1097-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 03/17/2017] [Accepted: 04/06/2017] [Indexed: 01/09/2023]
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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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