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Hoogenboom JL, Anderson WG. Using 15N to determine the metabolic fate of dietary nitrogen in North Pacific spiny dogfish (Squalus acanthias suckleyi). J Exp Biol 2023; 226:jeb244921. [PMID: 37306009 DOI: 10.1242/jeb.244921] [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: 08/24/2022] [Accepted: 06/05/2023] [Indexed: 06/13/2023]
Abstract
Marine elasmobranchs are ureosmotic, retaining large concentrations of urea to balance their internal osmotic pressure with that of the external marine environment. The synthesis of urea requires the intake of exogenous nitrogen to maintain whole-body nitrogen balance and satisfy obligatory osmoregulatory and somatic processes. We hypothesized that dietary nitrogen may be directed toward the synthesis of specific nitrogenous molecules in post-fed animals; specifically, we predicted the preferential accumulation and retention of labelled nitrogen would be directed towards the synthesis of urea necessary for osmoregulatory purposes. North Pacific spiny dogfish (Squalus acanthias suckleyi) were fed a single meal of 7 mmol l-1 15NH4Cl in a 2% ration by body mass of herring slurry via gavage. Dietary labelled nitrogen was tracked from ingestion to tissue incorporation and the subsequent synthesis of nitrogenous compounds (urea, glutamine, bulk amino acids, protein) in the intestinal spiral valve, plasma, liver and muscle. Within 20 h post-feeding, we found labelled nitrogen was incorporated into all tissues examined. The highest δ15N values were seen in the anterior region of the spiral valve at 20 h post-feeding, suggesting this region was particularly important in assimilating the dietary labelled nitrogen. In all tissues examined, enrichment of the nitrogenous compounds was sustained throughout the 168 h experimental period, highlighting the ability of these animals to retain and use dietary nitrogen for both osmoregulatory and somatic processes.
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Affiliation(s)
- J Lisa Hoogenboom
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB, Canada, R3T 2M5
- Bamfield Marine Sciences Centre, 100 Pachena Road, Bamfield, BC, Canada, V0R 1B0
| | - W Gary Anderson
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB, Canada, R3T 2M5
- Bamfield Marine Sciences Centre, 100 Pachena Road, Bamfield, BC, Canada, V0R 1B0
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2
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Hoogenboom JL, Anderson WG. Investigating nitrogen movement in North Pacific spiny dogfish (Squalus acanthias suckleyi), with focus on UT, Rhp2, and Rhbg mRNA abundance. J Comp Physiol B 2023:10.1007/s00360-023-01487-4. [PMID: 37162540 DOI: 10.1007/s00360-023-01487-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 03/15/2023] [Accepted: 04/14/2023] [Indexed: 05/11/2023]
Abstract
For ureosmotic marine elasmobranchs, the acquisition and retention of nitrogen is critical for the synthesis of urea. To better understand whole-body nitrogen homeostasis, we investigated mechanisms of nitrogen trafficking in North Pacific spiny dogfish (Squalus acanthias suckleyi). We hypothesized that the presence of nitrogen within the spiral valve lumen would affect both the transport of nitrogen and the mRNA abundance of a urea transporter (UT) and two ammonia transport proteins (Rhp2, Rhbg) within the intestinal epithelium. The in vitro preincubation of intestinal tissues in NH4Cl, intended to simulate dietary nitrogen availability, showed that increased ammonia concentrations did not significantly stimulate the net uptake of total urea or total methylamine. We also examined the mRNA abundance of UT, Rhp2, and Rhbg in the gills, kidney, liver, and spiral valve of fasted, fed, excess urea fed, and antibiotic-treated dogfish. After fasting, hepatic UT mRNA abundance was significantly lower, and Rhp2 mRNA in the gills was significantly higher than the other treatments. Feeding significantly increased Rhp2 mRNA levels in the kidney and mid spiral valve region. Both excess urea and antibiotics significantly reduced Rhbg mRNA levels along all three spiral valve regions. The antibiotic treatment also significantly diminished UT mRNA abundance levels in the anterior and mid spiral valve, and Rhbg mRNA levels in the kidney. In our study, no single treatment had significantly greater influence on the overall transcript abundance of the three transport proteins compared to another treatment, demonstrating the dynamic nature of nitrogen balance in these ancient fish.
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Affiliation(s)
- J Lisa Hoogenboom
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada.
- Bamfield Marine Sciences Centre, 100 Pachena Road, Bamfield, BC, V0R 1B0, Canada.
| | - W Gary Anderson
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
- Bamfield Marine Sciences Centre, 100 Pachena Road, Bamfield, BC, V0R 1B0, Canada
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3
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Hoogenboom JL, Wong MKS, Hyodo S, Anderson WG. Nitrogen transporters along the intestinal spiral valve of cloudy catshark (Scyliorhinus torazame): Rhp2, Rhbg, UT. Comp Biochem Physiol A Mol Integr Physiol 2023; 280:111418. [PMID: 36965831 DOI: 10.1016/j.cbpa.2023.111418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 03/16/2023] [Accepted: 03/21/2023] [Indexed: 03/27/2023]
Abstract
As part of their osmoregulatory strategy, marine elasmobranchs retain large quantities of urea to balance the osmotic pressure of the marine environment. The main source of nitrogen used to synthesize urea comes from the digestion and absorption of food across the gastrointestinal tract. In this study we investigated possible mechanisms of nitrogen movement across the spiral valve of the cloudy catshark (Scyliorhinus torazame) through the molecular identification of two Rhesus glycoprotein ammonia transporters (Rhp2 and Rhbg) and a urea transporter (UT). We used immunohistochemistry to determine the cellular localizations of Rhp2 and UT. Within the spiral valve, Rhp2 was expressed along the apical brush-border membrane, and UT was expressed along the basolateral membrane and the blood vessels. The mRNA abundance of Rhp2 was significantly higher in all regions of the spiral valve of fasted catsharks compared to fed catsharks. The mRNA abundance of UT was significantly higher in the anterior spiral valve of fasted catsharks compared to fed. The mRNA transcript of four ornithine urea cycle (OUC) enzymes were detected along the length of the spiral valve and in the renal tissue, indicating the synthesis of urea via the OUC occurs in these tissues. The presence of Rhp2, Rhbg, and UT along the length of the spiral valve highlights the importance of ammonia and urea movement across the intestinal tissues, and increases our understanding of the mechanisms involved in maintaining whole-body nitrogen homeostasis in the cloudy catshark.
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Affiliation(s)
- J Lisa Hoogenboom
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB R3T 0A8, Canada.
| | - Marty Kwok-Shing Wong
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, University of Tokyo, Kashiwa, Chiba, Japan
| | - Susumu Hyodo
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, University of Tokyo, Kashiwa, Chiba, Japan
| | - W Gary Anderson
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB R3T 0A8, Canada
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4
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Bregman G, Lalzar M, Livne L, Bigal E, Zemah-Shamir Z, Morick D, Tchernov D, Scheinin A, Meron D. Preliminary study of shark microbiota at a unique mix-species shark aggregation site, in the Eastern Mediterranean Sea. Front Microbiol 2023; 14:1027804. [PMID: 36910211 PMCID: PMC9996248 DOI: 10.3389/fmicb.2023.1027804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 01/16/2023] [Indexed: 02/25/2023] Open
Abstract
Sharks, as apex predators, play an essential ecological role in shaping the marine food web and maintaining healthy and balanced marine ecosystems. Sharks are sensitive to environmental changes and anthropogenic pressure and demonstrate a clear and rapid response. This designates them a "keystone" or "sentinel" group that may describe the structure and function of the ecosystem. As a meta-organism, sharks offer selective niches (organs) for microorganisms that can provide benefits for their hosts. However, changes in the microbiota (due to physiological or environmental changes) can turn the symbiosis into a dysbiosis and may affect the physiology, immunity and ecology of the host. Although the importance of sharks within the ecosystem is well known, relatively few studies have focused on the microbiome aspect, especially with long-term sampling. Our study was conducted at a site of coastal development in Israel where a mixed-species shark aggregation (November-May) is observed. The aggregation includes two shark species, the dusky (Carcharhinus obscurus) and sandbar (Carcharhinus plumbeus) which segregate by sex (females and males, respectively). In order to characterize the bacterial profile and examine the physiological and ecological aspects, microbiome samples were collected from different organs (gills, skin, and cloaca) from both shark species over 3 years (sampling seasons: 2019, 2020, and 2021). The bacterial composition was significantly different between the shark individuals and the surrounding seawater and between the shark species. Additionally, differences were apparent between all the organs and the seawater, and between the skin and gills. The most dominant groups for both shark species were Flavobacteriaceae, Moraxellaceae, and Rhodobacteraceae. However, specific microbial biomarkers were also identified for each shark. An unexpected difference in the microbiome profile and diversity between the 2019-2020 and 2021 sampling seasons, revealed an increase in the potential pathogen Streptococcus. The fluctuations in the relative abundance of Streptococcus between the months of the third sampling season were also reflected in the seawater. Our study provides initial information on shark microbiome in the Eastern Mediterranean Sea. In addition, we demonstrated that these methods were also able to describe environmental episodes and the microbiome is a robust measure for long-term ecological research.
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Affiliation(s)
- Goni Bregman
- Morris Kahn Marine Research Station, Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel
| | - Maya Lalzar
- Bioinformatics Services Unit, University of Haifa, Haifa, Israel
| | - Leigh Livne
- Morris Kahn Marine Research Station, Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel
| | - Eyal Bigal
- Morris Kahn Marine Research Station, Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel
| | - Ziv Zemah-Shamir
- Morris Kahn Marine Research Station, Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel
| | - Danny Morick
- Morris Kahn Marine Research Station, Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel
| | - Dan Tchernov
- Morris Kahn Marine Research Station, Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel
| | - Aviad Scheinin
- Morris Kahn Marine Research Station, Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel
| | - Dalit Meron
- Morris Kahn Marine Research Station, Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel
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Osmorespiratory compromise in an elasmobranch: oxygen consumption, ventilation and nitrogen metabolism during recovery from exhaustive exercise in dogfish sharks (Squalus suckleyi). J Comp Physiol B 2022; 192:647-657. [PMID: 35838789 DOI: 10.1007/s00360-022-01447-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 05/30/2022] [Accepted: 06/15/2022] [Indexed: 10/17/2022]
Abstract
The functional trade-off between respiratory gas exchange versus osmolyte and water balance that occurs at the thin, highly vascularized gills of fishes has been termed the osmorespiratory compromise. Increases in gas exchange capacity for meeting elevated oxygen demands can end up favoring the passive movement of osmolytes and water, potentially causing a disturbance in osmotic balance. This phenomenon has been studied only sparsely in marine elasmobranchs. Our goal was to evaluate the effects of exhaustive exercise (as a modulator of oxygen demand) on oxygen consumption (MO2), branchial losses of nitrogenous products (ammonia and urea-N), diffusive water exchange rates, and gill ventilation (frequency and amplitude), in the Pacific spiny dogfish (Squalus suckleyi). To that end, MO2, osmolyte fluxes, diffusive water exchange rate, and ventilation dynamics were first measured under resting control conditions, then sharks were exercised until exhaustion (20 min), and the same parameters were monitored for the subsequent 4 h of recovery. While MO2 nearly doubled immediately after exercise and remained elevated for 2 h, ventilation dynamics did not change, suggesting that fish were increasing oxygen extraction efficiency at the gills. Diffusive water flux rates (measured over 0-2 h of recovery) were not affected. Ammonia losses were elevated by 7.6-fold immediately after exercise and remained elevated for 3 h into recovery, while urea-N losses were elevated only 1.75-fold and returned to control levels after 1 h. These results are consistent with previous investigations using different challenges (hypoxia, high temperature) and point to a tighter regulation of urea-N conservation mechanisms at the gills, likely due to the use of urea as a prized osmolyte in elasmobranchs. Environmental hyperoxia offered no relief from the osmorespiratory compromise, as there were no effects on any of the parameters measured during recovery from exhaustive exercise.
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Shipley ON, Olin JA, Whiteman JP, Bethea DM, Newsome SD. Bulk and amino acid nitrogen isotopes suggest shifting nitrogen balance of pregnant sharks across gestation. Oecologia 2022; 199:313-328. [PMID: 35718810 DOI: 10.1007/s00442-022-05197-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 05/21/2022] [Indexed: 10/18/2022]
Abstract
Nitrogen isotope (δ15N) analysis of bulk tissues and individual amino acids (AA) can be used to assess how consumers maintain nitrogen balance with broad implications for predicting individual fitness. For elasmobranchs, a ureotelic taxa thought to be constantly nitrogen limited, the isotopic effects associated with nitrogen-demanding events such as prolonged gestation remain unknown. Given the linkages between nitrogen isotope variation and consumer nitrogen balance, we used AA δ15N analysis of muscle and liver tissue collected from female bonnethead sharks (Sphyrna tiburo, n = 16) and their embryos (n = 14) to explore how nitrogen balance may vary across gestation. Gestational stage was a strong predictor of bulk tissue and AA δ15N values in pregnant shark tissues, decreasing as individuals neared parturition. This trend was observed in trophic (e.g., Glx, Ala, Val), source (e.g., Lys), and physiological (e.g., Gly) AAs. Several potential mechanisms may explain these results including nitrogen conservation, scavenging, and bacterially mediated breakdown of urea to free ammonia that is used to synthesize AAs. We observed contrasting patterns of isotopic discrimination in embryo tissues, which generally became enriched in 15N throughout development. This was attributed to greater excretion of nitrogenous waste in more developed embryos, and the role of physiologically sensitive AAs (i.e., Gly and Ser) to molecular processes such as nucleotide synthesis. These findings underscore how AA isotopes can quantify shifts in nitrogen balance, providing unequivocal evidence for the role of physiological condition in driving δ15N variation in both bulk tissues and individual AAs.
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Affiliation(s)
- Oliver N Shipley
- Department of Biology, University of New Mexico, Albuquerque, NM, 87131, USA. .,Beneath the Waves, PO Box 126, Herndon, VA, 20172, USA.
| | - Jill A Olin
- Biological Sciences, Great Lakes Research Center, Michigan Technological University, Houghton, MI, 49931, USA
| | - John P Whiteman
- Department of Biological Sciences, Old Dominion University, Norfolk, VA, 23529, USA
| | - Dana M Bethea
- NOAA Fisheries Southeast Regional Office, Saint Petersburg, FL, 33701, USA
| | - Seth D Newsome
- Department of Biology, University of New Mexico, Albuquerque, NM, 87131, USA
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7
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The aquaporin 8 (AQP8) membrane channel gene is present in the elasmobranch dogfish (Squalus acanthias) genome and is expressed in brain but not in gill, kidney or intestine. Comp Biochem Physiol B Biochem Mol Biol 2022; 260:110730. [PMID: 35248695 DOI: 10.1016/j.cbpb.2022.110730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 02/27/2022] [Accepted: 03/01/2022] [Indexed: 11/23/2022]
Abstract
The transport mechanisms for water, ammonia and urea in elasmobranch gill, kidney and gastrointestinal tract remain to be fully elucidated. Aquaporin 8 (AQP8) is a known water, ammonia and urea channel that is expressed in the kidney and respiratory and gastrointestinal tracts of mammals and teleost fish. However, at the initiation of this study in late 2019, there was no copy of an elasmobranch aquaporin 8 gene identified in the genebank even for closely related holocephalon species such as elephant fish (Callorhinchus milii) or for the elasmobranch little skate (Leucoraja erinacea). A transcriptomic study in spiny dogfish (Squalus acanthias) also failed to identify a copy. Hence this study has remedied this and identified the AQP8 cDNA sequence using degenerate PCR. Agarose electrophoresis of degenerate PCR reactions from dogfish tissues showed a strong band from brain cDNA and faint bands of a similar size in gill and liver. 5' and 3' RACE was used to complete the AQP8 cDNA sequence. Primers were then designed for further PCR reactions to determine the distribution of AQP8 mRNA expression in dogfish tissues. This showed that AQP8 is only expressed in dogfish brain and AQP8 therefore clearly can play no role in water, ammonia and urea transport in the gill, kidney or gastrointestinal tract. The role of AQP8 in dogfish brain remains to be determined.
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Perry CT, Pratte ZA, Clavere-Graciette A, Ritchie KB, Hueter RE, Newton AL, Fischer GC, Dinsdale EA, Doane MP, Wilkinson KA, Bassos-Hull K, Lyons K, Dove ADM, Hoopes LA, Stewart FJ. Elasmobranch microbiomes: emerging patterns and implications for host health and ecology. Anim Microbiome 2021; 3:61. [PMID: 34526135 PMCID: PMC8444439 DOI: 10.1186/s42523-021-00121-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 08/21/2021] [Indexed: 12/20/2022] Open
Abstract
Elasmobranchs (sharks, skates and rays) are of broad ecological, economic, and societal value. These globally important fishes are experiencing sharp population declines as a result of human activity in the oceans. Research to understand elasmobranch ecology and conservation is critical and has now begun to explore the role of body-associated microbiomes in shaping elasmobranch health. Here, we review the burgeoning efforts to understand elasmobranch microbiomes, highlighting microbiome variation among gastrointestinal, oral, skin, and blood-associated niches. We identify major bacterial lineages in the microbiome, challenges to the field, key unanswered questions, and avenues for future work. We argue for prioritizing research to determine how microbiomes interact mechanistically with the unique physiology of elasmobranchs, potentially identifying roles in host immunity, disease, nutrition, and waste processing. Understanding elasmobranch–microbiome interactions is critical for predicting how sharks and rays respond to a changing ocean and for managing healthy populations in managed care.
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Affiliation(s)
- Cameron T Perry
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA.
| | - Zoe A Pratte
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA.,Department of Microbiology and Immunology, Montana State University, Bozeman, MT, USA
| | | | - Kim B Ritchie
- Department of Natural Sciences, University of South Carolina Beaufort, Beaufort, SC, USA
| | - Robert E Hueter
- Sharks and Rays Conservation Research Program, Mote Marine Laboratory, Sarasota, FL, USA.,OCEARCH, Park City, UT, USA
| | - Alisa L Newton
- Disney's Animals, Science and Environment, Orlando, FL, USA
| | - G Christopher Fischer
- OCEARCH, Park City, UT, USA.,Marine Science Research Institute, Jacksonville University, Jacksonville, FL, USA
| | - Elizabeth A Dinsdale
- College of Science and Engineering, Flinders University, Bedford Park, SA, Australia
| | - Michael P Doane
- College of Science and Engineering, Flinders University, Bedford Park, SA, Australia
| | - Krystan A Wilkinson
- Sharks and Rays Conservation Research Program, Mote Marine Laboratory, Sarasota, FL, USA.,Chicago Zoological Society's Sarasota Dolphin Research Program ℅ Mote Marine Laboratory, Sarasota, FL, USA
| | - Kim Bassos-Hull
- Sharks and Rays Conservation Research Program, Mote Marine Laboratory, Sarasota, FL, USA
| | - Kady Lyons
- Research and Conservation Department, Georgia Aquarium, Atlanta, GA, USA
| | - Alistair D M Dove
- Research and Conservation Department, Georgia Aquarium, Atlanta, GA, USA
| | - Lisa A Hoopes
- Research and Conservation Department, Georgia Aquarium, Atlanta, GA, USA
| | - Frank J Stewart
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA.,Department of Microbiology and Immunology, Montana State University, Bozeman, MT, USA
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Wood CM, Liew HJ, De Boeck G, Hoogenboom JL, Anderson WG. Nitrogen handling in the elasmobranch gut: a role for microbial urease. ACTA ACUST UNITED AC 2019; 222:jeb.194787. [PMID: 30530835 DOI: 10.1242/jeb.194787] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 12/03/2018] [Indexed: 11/20/2022]
Abstract
Ureotelic elasmobranchs require nitrogen for both protein growth and urea-based osmoregulation, and therefore are probably nitrogen-limited in nature. Mechanisms exist for retaining and/or scavenging nitrogen in the gills, kidney, rectal gland and gut, but as yet, the latter are not well characterized. Intestinal sac preparations of the Pacific spiny dogfish shark (Squalus acanthias suckleyi) incubated in vitro strongly reabsorbed urea from the lumen after feeding, but mucosal fluid ammonia concentrations increased with incubation time. Phloretin (0.25 mmol l-1, which blocked urea reabsorption) greatly increased the rate of ammonia accumulation in the lumen. A sensitive [14C]urea-based assay was developed to examine the potential role of microbial urease in this ammonia production. Urease activity was detected in chyme/intestinal fluid and intestinal epithelial tissue of both fed and fasted sharks. Urease was not present in gall-bladder bile. Urease activities were highly variable among animals, but generally greater in chyme than in epithelia, and greater in fed than in fasted sharks. Comparable urease activities were found in chyme and epithelia of the Pacific spotted ratfish (Hydrolagus colliei), a ureotelic holocephalan, but were much lower in ammonotelic teleosts. Urease activity in dogfish chyme was inhibited by acetohydroxamic acid (1 mmol l-1) and by boiling. Treatment of dogfish gut sac preparations with acetohydroxamic acid blocked ammonia production, changing net ammonia accumulation into net ammonia absorption. We propose that microbial urease plays an important role in nitrogen handling in the elasmobranch intestine, allowing some urea-N to be converted to ammonia, which is then reabsorbed for amino acid synthesis or reconversion to urea.
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Affiliation(s)
- Chris M Wood
- Bamfield Marine Sciences Centre, 100 Pachena Road, Bamfield, BC V0R 1B0, Canada .,Department of Zoology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada.,Department of Biology, McMaster University, 1280 Main St. West, Hamilton, ON L8S 4K1, Canada
| | - Hon Jung Liew
- Bamfield Marine Sciences Centre, 100 Pachena Road, Bamfield, BC V0R 1B0, Canada.,Institute of Tropical Aquaculture, Universiti Malaysia Terengganu, 21030 Kuala Terengganu, Terengganu, Malaysia
| | - Gudrun De Boeck
- Bamfield Marine Sciences Centre, 100 Pachena Road, Bamfield, BC V0R 1B0, Canada.,Systemic Physiological and Ecotoxicological Research, Department of Biology, University of Antwerp, Groenenborgerlaan 171, BE-2020 Antwerp, Belgium
| | - J Lisa Hoogenboom
- Bamfield Marine Sciences Centre, 100 Pachena Road, Bamfield, BC V0R 1B0, Canada.,Department of Biological Sciences, University of Manitoba, Winnipeg, MB, Canada R3T 2N2
| | - W Gary Anderson
- Bamfield Marine Sciences Centre, 100 Pachena Road, Bamfield, BC V0R 1B0, Canada.,Department of Biological Sciences, University of Manitoba, Winnipeg, MB, Canada R3T 2N2
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10
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Amino acid isotope discrimination factors for a carnivore: physiological insights from leopard sharks and their diet. Oecologia 2018; 188:977-989. [DOI: 10.1007/s00442-018-4276-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 10/14/2018] [Indexed: 11/26/2022]
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11
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Giacomin M, Schulte PM, Wood CM. Differential Effects of Temperature on Oxygen Consumption and Branchial Fluxes of Urea, Ammonia, and Water in the Dogfish Shark (Squalus acanthias suckleyi). Physiol Biochem Zool 2017; 90:627-637. [DOI: 10.1086/694296] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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12
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Knight K. Pacific spiny dogfish successfully scavenge ammonia from sea. J Exp Biol 2016. [DOI: 10.1242/jeb.150201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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