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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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Treberg JR, Martyniuk CJ, Moyes CD. Getting the most out of reductionist approaches in comparative biochemistry and physiology. Comp Biochem Physiol B Biochem Mol Biol 2020; 250:110483. [DOI: 10.1016/j.cbpb.2020.110483] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 07/06/2020] [Accepted: 07/09/2020] [Indexed: 12/17/2022]
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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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Contractile function of the excised hagfish heart during anoxia exposure. J Comp Physiol B 2019; 189:199-211. [PMID: 30725175 DOI: 10.1007/s00360-019-01208-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 01/24/2019] [Accepted: 01/29/2019] [Indexed: 01/19/2023]
Abstract
Pacific hagfish, Eptatretus stoutii, can recover from 36 h of anoxia and their systemic hearts continue to work throughout the exposure. Recent work demonstrates that glycogen stores are utilized in the E. stoutii heart during anoxia but that these are not sufficient to support the measured rate of ATP production. One metabolic fuel that could supplement glycogen during anoxia is glycerol. This substrate can be derived from lipid stores, stored in the heart, or delivered via the blood. The purpose of this study was to determine the effect of glycerol on the contractile function of the excised E. stoutii heart during anoxia exposure. When excised hearts, perfused with metabolite free saline (mf-saline), were exposed to anoxia for 12 h, there was no difference in heart rate, pressure generation (max-dP), rate of contraction (max-dP/dtsys), or rate of relaxation (max-dP/dtdia) compared to hearts perfused with mf-saline in normoxia. However, hearts perfused with saline containing glycerol (gly-saline) in anoxia had higher max-dP, max-dP/dtsys, and max-dP/dtdia than hearts perfused with mf-saline in anoxia. Tissue levels of glycerol increased when hearts were perfused with gly-saline in normoxia, but not when perfused with gly-saline in anoxia. Anoxia exposure did not affect the activities of triglyceride lipase, glycerol kinase, or glycerol-3-phosphate dehydrogenase. This study suggests that glycerol stimulates cardiac function in the hagfish but that it is not derived from stored lipids. How glycerol may stimulate contraction is not known. This could be as an energy substrate, as an allosteric factor, or a combination of the two.
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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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Yancey PH, Speers-Roesch B, Atchinson S, Reist JD, Majewski AR, Treberg JR. Osmolyte Adjustments as a Pressure Adaptation in Deep-Sea Chondrichthyan Fishes: An Intraspecific Test in Arctic Skates (Amblyraja hyperborea) along a Depth Gradient. Physiol Biochem Zool 2018; 91:788-796. [DOI: 10.1086/696157] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Yancey PH, Siebenaller JF. Co-evolution of proteins and solutions: protein adaptation versus cytoprotective micromolecules and their roles in marine organisms. ACTA ACUST UNITED AC 2016; 218:1880-96. [PMID: 26085665 DOI: 10.1242/jeb.114355] [Citation(s) in RCA: 106] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Organisms experience a wide range of environmental factors such as temperature, salinity and hydrostatic pressure, which pose challenges to biochemical processes. Studies on adaptations to such factors have largely focused on macromolecules, especially intrinsic adaptations in protein structure and function. However, micromolecular cosolutes can act as cytoprotectants in the cellular milieu to affect biochemical function and they are now recognized as important extrinsic adaptations. These solutes, both inorganic and organic, have been best characterized as osmolytes, which accumulate to reduce osmotic water loss. Singly, and in combination, many cosolutes have properties beyond simple osmotic effects, e.g. altering the stability and function of proteins in the face of numerous stressors. A key example is the marine osmolyte trimethylamine oxide (TMAO), which appears to enhance water structure and is excluded from peptide backbones, favoring protein folding and stability and counteracting destabilizers like urea and temperature. Co-evolution of intrinsic and extrinsic adaptations is illustrated with high hydrostatic pressure in deep-living organisms. Cytosolic and membrane proteins and G-protein-coupled signal transduction in fishes under pressure show inhibited function and stability, while revealing a number of intrinsic adaptations in deep species. Yet, intrinsic adaptations are often incomplete, and those fishes accumulate TMAO linearly with depth, suggesting a role for TMAO as an extrinsic 'piezolyte' or pressure cosolute. Indeed, TMAO is able to counteract the inhibitory effects of pressure on the stability and function of many proteins. Other cosolutes are cytoprotective in other ways, such as via antioxidation. Such observations highlight the importance of considering the cellular milieu in biochemical and cellular adaptation.
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Affiliation(s)
- Paul H Yancey
- Department of Biology, Whitman College, Walla Walla, WA 99362, USA
| | - Joseph F Siebenaller
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
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Hagfish: Champions of CO2 tolerance question the origins of vertebrate gill function. Sci Rep 2015; 5:11182. [PMID: 26057989 PMCID: PMC4460890 DOI: 10.1038/srep11182] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 04/07/2015] [Indexed: 11/30/2022] Open
Abstract
The gill is widely accepted to have played a key role in the adaptive radiation of early vertebrates by supplanting the skin as the dominant site of gas exchange. However, in the most basal extant craniates, the hagfishes, gills play only a minor role in gas exchange. In contrast, we found hagfish gills to be associated with a tremendous capacity for acid-base regulation. Indeed, Pacific hagfish exposed acutely to severe sustained hypercarbia tolerated among the most severe blood acidoses ever reported (1.2 pH unit reduction) and subsequently exhibited the greatest degree of acid-base compensation ever observed in an aquatic chordate. This was accomplished through an unprecedented increase in plasma [HCO3−] (>75 mM) in exchange for [Cl−]. We thus propose that the first physiological function of the ancestral gill was acid-base regulation, and that the gill was later co-opted for its central role in gas exchange in more derived aquatic vertebrates.
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Edwards SL, Arnold J, Blair SD, Pray M, Bradley R, Erikson O, Walsh PJ. Ammonia excretion in the Atlantic hagfish (Myxine glutinosa) and responses of an Rhc glycoprotein. Am J Physiol Regul Integr Comp Physiol 2015; 308:R769-78. [DOI: 10.1152/ajpregu.00355.2014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Accepted: 02/20/2015] [Indexed: 12/21/2022]
Abstract
Hagfishes, the most ancient of the extant craniates, demonstrate a high tolerance for a number of unfavorable environmental conditions, including elevated ammonia. Proposed mechanisms of ammonia excretion in aquatic organisms include vesicular NH4+ transport and release by exocytosis in marine crabs, and passive NH3 diffusion, active NH4+ transport, and paracellular leakage of NH3 or NH4+ across the gills of fishes. Recently, an emerging paradigm suggests that Rhesus glycoproteins play a vital role in ammonia transport in both aquatic invertebrates and vertebrates. This study has identified an Rh glycoprotein ortholog from the gills of Atlantic hagfish. The hagfish Rhcg shares a 56–60% amino acid identity to other vertebrate Rhcg cDNAs. Sequence information was used to produce an anti-hagfish Rhcg (hRhcg) antibody. We have used hRhcg to localize protein expression to epithelial cells of the gill and the skin. In addition, we have quantified hRhcg expression following exposure to elevated plasma ammonia levels. Animals exposed to a 3 mmol/kg NH4Cl load resulted in significantly elevated plasma ammonia concentrations compared with controls for up to 4 h postinjection. This correlated with net ammonia excretion rates that were also significantly elevated for up to 4 h postinjection. Rhcg mRNA expression in both the gill and skin was significantly elevated by 15 min and 1 h, respectively, and hRhcg protein expression in gills was significantly elevated at 2, 4, and 8 h postinjection. These results demonstrate a potential role for Rhcg in the excretion of ammonia in the Atlantic hagfish.
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Affiliation(s)
- Susan L. Edwards
- Department of Biology, Appalachian State University, Boone, North Carolina
- Mount Desert Island Biological Laboratory, Salisbury Cove, Maine; and
| | - Justin Arnold
- Department of Biology, Appalachian State University, Boone, North Carolina
- Mount Desert Island Biological Laboratory, Salisbury Cove, Maine; and
| | - Salvatore D. Blair
- Department of Biology, Appalachian State University, Boone, North Carolina
- Mount Desert Island Biological Laboratory, Salisbury Cove, Maine; and
| | - Margaret Pray
- Department of Biology, Appalachian State University, Boone, North Carolina
- Mount Desert Island Biological Laboratory, Salisbury Cove, Maine; and
| | - Rachel Bradley
- Department of Biology, Appalachian State University, Boone, North Carolina
- Mount Desert Island Biological Laboratory, Salisbury Cove, Maine; and
| | - Olivia Erikson
- Mount Desert Island Biological Laboratory, Salisbury Cove, Maine; and
| | - Patrick J. Walsh
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
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Extrabranchial mechanisms of systemic pH recovery in hagfish (Eptatretus stoutii). Comp Biochem Physiol A Mol Integr Physiol 2014; 168:82-9. [DOI: 10.1016/j.cbpa.2013.11.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 11/14/2013] [Accepted: 11/20/2013] [Indexed: 11/19/2022]
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11
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Anderson WG, Nawata CM, Wood CM, Piercey-Normore MD, Weihrauch D. Body fluid osmolytes and urea and ammonia flux in the colon of two chondrichthyan fishes, the ratfish, Hydrolagus colliei, and spiny dogfish, Squalus acanthias. Comp Biochem Physiol A Mol Integr Physiol 2012; 161:27-35. [PMID: 21911071 DOI: 10.1016/j.cbpa.2011.08.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Revised: 08/29/2011] [Accepted: 08/29/2011] [Indexed: 12/29/2022]
Abstract
The present study has examined the role of the colon in regulating ammonia and urea nitrogen balance in two species of chondrichthyans, the ratfish, Hydrolagus colliei (a holocephalan) and the spiny dogfish, Squalus acanthias (an elasmobranch). Stripped colonic tissue from both the dogfish and ratfish was mounted in an Ussing chamber and in both species bi-directional urea flux was found to be negligible. Urea uptake by the mucosa and serosa of the isolated colonic epithelium through accumulation of (14)C-urea was determined to be 2.8 and 6.2 fold greater in the mucosa of the dogfish compared to the serosa of the dogfish and the mucosa of the ratfish respectively. Furthermore, there was no difference between serosal and mucosal accumulation of (14)C-urea in the ratfish. Through the addition of 2mM NH(4)Cl to the mucosal side of each preparation the potential for ammonia flux was also examined. This was again found to be negligible in both species suggesting that the colon is an extremely tight epithelium to the movement of both urea and ammonia. Plasma, chyme and bile fluid samples were also taken from the agastric ratfish and were compared with solute concentrations of equivalent body fluids in the dogfish. Finally molecular analysis revealed expression of 3 isoforms of the urea transport protein (UT) and an ammonia transport protein (Rhbg) in the gill, intestine, kidney and colon of the ratfish. Partial nucleotide sequences of the UT-1, 2 and 3 isoforms in the ratfish had 95, 95 and 92% identity to the equivalent UT isoforms recently identified in another holocephalan, the elephantfish, Callorhinchus milii. Finally, the nucleotide sequence of the Rhbg identified in the ratfish had 73% identity to the Rhbg protein recently identified in the little skate, Leucoraja erinacea.
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Affiliation(s)
- W Gary Anderson
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB, Canada.
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12
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Takagi W, Kajimura M, Bell JD, Toop T, Donald JA, Hyodo S. Hepatic and extrahepatic distribution of ornithine urea cycle enzymes in holocephalan elephant fish (Callorhinchus milii). Comp Biochem Physiol B Biochem Mol Biol 2011; 161:331-40. [PMID: 22227372 DOI: 10.1016/j.cbpb.2011.12.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2011] [Revised: 12/15/2011] [Accepted: 12/17/2011] [Indexed: 11/15/2022]
Abstract
Cartilaginous fish comprise two subclasses, the Holocephali (chimaeras) and Elasmobranchii (sharks, skates and rays). Little is known about osmoregulatory mechanisms in holocephalan fishes except that they conduct urea-based osmoregulation, as in elasmobranchs. In the present study, we examined the ornithine urea cycle (OUC) enzymes that play a role in urea biosynthesis in the holocephalan elephant fish, Callorhinchus milii (cm). We obtained a single mRNA encoding carbamoyl phosphate synthetase III (cmCPSIII) and ornithine transcarbamylase (cmOTC), and two mRNAs encoding glutamine synthetases (cmGSs) and two arginases (cmARGs), respectively. The two cmGSs were structurally and functionally separated into two types: brain/liver/kidney-type cmGS1 and muscle-type cmGS2. Furthermore, two alternatively spliced transcripts with different sizes were found for cmgs1 gene. The longer transcript has a putative mitochondrial targeting signal (MTS) and was predominantly expressed in the liver and kidney. MTS was not found in the short form of cmGS1 and cmGS2. A high mRNA expression and enzyme activities were found in the liver and muscle. Furthermore, in various tissues examined, mRNA levels of all the enzymes except cmCPSIII were significantly increased after hatching. The data show that the liver is the important organ for urea biosynthesis in elephant fish, but, extrahepatic tissues such as the kidney and muscle may also contribute to the urea production. In addition to the role of the extrahepatic tissues and nitrogen metabolism, the molecular and functional characteristics of multiple isoforms of GSs and ARGs are discussed.
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Affiliation(s)
- Wataru Takagi
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba 277-8564, Japan.
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Laxson CJ, Condon NE, Drazen JC, Yancey PH. Decreasing Urea∶Trimethylamine N-Oxide Ratios with Depth in Chondrichthyes: A Physiological Depth Limit? Physiol Biochem Zool 2011; 84:494-505. [DOI: 10.1086/661774] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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The curious case of the chemical composition of hagfish tissues—50years on. Comp Biochem Physiol A Mol Integr Physiol 2010; 157:111-5. [DOI: 10.1016/j.cbpa.2010.06.164] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Revised: 06/04/2010] [Accepted: 06/05/2010] [Indexed: 11/21/2022]
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Herr JE, Winegard TM, O'Donnell MJ, Yancey PH, Fudge DS. Stabilization and swelling of hagfish slime mucin vesicles. ACTA ACUST UNITED AC 2010; 213:1092-9. [PMID: 20228345 DOI: 10.1242/jeb.038992] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
When agitated, Atlantic hagfish (Myxine glutinosa) produce large quantities of slime that consists of hydrated bundles of protein filaments and membrane-bound mucin vesicles from numerous slime glands. When the slime exudate contacts seawater, the thread bundles unravel and the mucin vesicles swell and rupture. Little is known about the mechanisms of vesicle rupture in seawater and stabilization within the gland, although it is believed that the vesicle membrane is permeable to most ions except polyvalent anions. We hypothesized that the most abundant compounds within the slime gland exudate have a stabilizing effect on the mucin vesicles. To test this hypothesis, we measured the chemical composition of the fluid component of hagfish slime exudate and conducted functional assays with these solutes to test their ability to keep the vesicles in a condensed state. We found K(+) concentrations that were elevated relative to plasma, and Na(+), Cl(-) and Ca(2+) concentrations that were considerably lower. Our analysis also revealed high levels of methylamines such as trimethylamine oxide (TMAO), betaine and dimethylglycine, which had a combined concentration of 388 mmol l(-1) in the glandular fluid. In vitro rupture assays demonstrated that both TMAO and betaine had a significant effect on rupture, but neither was capable of completely abolishing mucin swelling and rupture, even at high concentrations. This suggests that some other mechanism such as the chemical microenvironment within gland mucous cells, or hydrostatic pressure is responsible for stabilization of the vesicles within the gland.
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Affiliation(s)
- J E Herr
- Department of Integrative Biology, University of Guelph, Guelph, ON N1G-2W1 Canada
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Tait LW, Simpson CWC, Takei Y, Forster ME. Hagfish natriuretic peptide changes urine flow rates and vascular tensions in a hagfish. Comp Biochem Physiol C Toxicol Pharmacol 2009; 150:45-9. [PMID: 19223021 DOI: 10.1016/j.cbpc.2009.02.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2008] [Revised: 02/10/2009] [Accepted: 02/10/2009] [Indexed: 10/21/2022]
Abstract
Since the first report of their natriuretic effect on mammalian kidneys the relative influences of natriuretic peptides (NPs) on volume and salt regulation in vertebrates have been debated. As marine osmoconformers, with plasma ionic concentrations similar to seawater, the actions of NPs on hagfishes may provide information on their primordial role. A synthetic natriuretic peptide derived from Eptatretus burgeri (hNP) increased urine production rates in E. cirrhatus at 3x10(-8) M. It also contracted afferent branchial and segmental arteries at low concentrations (1x10(-10) M) and relaxed them at 3x10(-8) M. Thus, hNP has a renal effect and at higher concentrations causes vascular relaxation suggesting a role in volume regulation and the prevention of cardiac overloading. Rat ANP (rANP) stimulated sodium efflux from both isolated, perfused gill pouches and the whole animal. rANP also reduced subcutaneous sinus haematocrit relative to that in the ventral aorta, which is consistent with a vasodilatory role.
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Affiliation(s)
- L W Tait
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
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17
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The effects of variable water salinity and ionic composition on the plasma status of the Pacific Hagfish (Eptatretus stoutii). J Comp Physiol B 2009; 179:721-8. [DOI: 10.1007/s00360-009-0355-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2008] [Revised: 02/19/2009] [Accepted: 03/19/2009] [Indexed: 10/20/2022]
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Foster JM, Forster ME. Effects of salinity manipulations on blood pressures in an osmoconforming chordate, the hagfish, Eptatretus cirrhatus. J Comp Physiol B 2006; 177:31-9. [PMID: 16868752 DOI: 10.1007/s00360-006-0106-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2006] [Revised: 06/14/2006] [Accepted: 06/21/2006] [Indexed: 11/24/2022]
Abstract
Arterial and venous pressures were measured in hagfishes subjected to acute changes in salinity. The osmotic pressure of the seawater (SW) was increased or decreased by approximately 10%. Sixty minutes after the change in medium osmolarity the osmotic pressure of the blood corresponded with that of the medium. Following transfer to 90% SW all measured parameters changed as predicted for a passive increase in blood volume, apart from the pressure in the posterior cardinal vein (PCV) which fell. By 2 h dorsal aortic (DA) pressure and pressure in the PCV and supraintestinal vein had returned to pre-change values. In contrast, following exposure to 110% SW, pressures fell and apart from the supraintestinal vein they remained low at 120 min. At 24 h, DA pressure was lower than pre-change values for both groups. The data are consistent with the concept of central venous tone being regulated in hagfishes, which cope better with volume expansion than volume depletion.
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Affiliation(s)
- J M Foster
- School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch 8020, New Zealand
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Forster ME, Russell MJ, Hambleton DC, Olson KR. Blood and extracellular fluid volume in whole body and tissues of the Pacific hagfish, Eptatretus stouti. Physiol Biochem Zool 2001; 74:750-6. [PMID: 11517460 DOI: 10.1086/323032] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/14/2001] [Indexed: 11/03/2022]
Abstract
Whole-body and 20 individual-tissue (51)Cr-RBC (red cell space; RCS) and (99)Tc-diethylenetriaminepentaacetic acid (extracellular space; ECS) spaces were measured in seven unanesthetized Pacific hagfish (Eptatretus stouti). Volume indicators were administered via a dorsal aortic cannula implanted the previous day. Blood samples were collected at 6, 12, 18, and 24 h after injection. Tissues were removed at 24 h and radioactivity was measured; tissue water content (percent of wet weight) was determined by desiccation at 95 degrees C for 48 h. Mixing rates of both indicators were identical and were essentially complete by 12 h, indicating that blood convection is the rate-limiting process. At 24 h, the whole-body RCS was 19.3+/-2.1 mL kg(-1) body weight, and the ECS was 338.5+/-15.2 mL kg(-1) body weight. Blood volume estimated from the 24-h RCS and the mean central hematocrit (14%) was 137.9 mL kg(-1) body weight. Liver RCS (118.6+/-30.5 microL g(-1) tissue weight) was twice that of any other tissue and was also the most variable, ranging from 59 to 263 microL g(-1), whereas liver ECS (406.0+/-34.3 microL g(-1)) was in the range of other tissues, and water content (66.9%+/-3.5%) was low. Gill RCS (55.9+/-5.7 microL g(-1)), ECS (415.3+/-37.7 microL g(-1)), and percent water (83.1%+/-0.8%) were higher than most other tissues. RCS, ECS, and percent water were consistently lowest in ovum (1.1+/-0.02 microL g(-1), 111.1+/-4.3 microL g(-1), 51.3%+/-3.5%, respectively). Tongue, notocord, and myotome had generally lower RCS (2.1+/-0.4, 2.2+/-0.5, 7.1+/-0.1 microL g(-1), respectively) and ECS (121.2+/-7.0, 246.3+/-17.4, 185.3+/-16.7 microL g(-1), respectively), although their water content was in the midrange (74.7+/-0.5, 81.2+/-1.6, 74.4%+/-0.6%, respectively). Skin had a low RCS (6.8+/-1.1) and midrange ECS (387.5+/-28.0) but very low water content (61.2%+/-2.1%). These findings confirm that hagfish blood volume is at least twice as large as other fish, whereas our estimate of extracellular fluid volume is larger than previously reported and more in line with the predicted interstitial volume. RCS, ECS, and water content vary, often independently, between tissues, which may perhaps be indicative of specific tissue needs or functions. A distinct spleen is lacking in hagfish, and the liver appears to serve this function by sequestering red cells. To our knowledge, this is the first report of tissue ECS in Myxiniformes.
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Affiliation(s)
- M E Forster
- Department of Zoology, University of Canterbury, Private Bag 4800, Christchurch, New Zealand
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Olson KR, Russell MJ, Forster ME. Hypoxic vasoconstriction of cyclostome systemic vessels: the antecedent of hypoxic pulmonary vasoconstriction? Am J Physiol Regul Integr Comp Physiol 2001; 280:R198-206. [PMID: 11124152 DOI: 10.1152/ajpregu.2001.280.1.r198] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Hypoxic vasoconstriction (HV) is an intrinsic response of mammalian pulmonary vascular smooth muscle (VSM). In the present study, HV was examined by myography of vessel rings from three primitive vertebrates: New Zealand hagfish (NZH), Pacific hagfish (PH), and sea lamprey (SL). Hypoxia dilated pre-gill arteries (ventral aorta, afferent branchial) from all species, whereas it contracted systemic arteries [dorsal aorta (DA), efferent branchial, celiacomesenteric]. DA HV was reproducible over several days, and it could be sustained in NZH for 8 h without adverse effects. Tension was proportional to PO(2), and half-maximal HV was obtained at PO(2) (mmHg) of 4.7 +/- 0. 2 (NZH), 0.8 +/- 0.1 (PH), and 10.7 +/- 1.9 (SL). HV did not require preconditioning (preexisting contractile stimulus) and was unaffected by elevated extracellular potassium (200 mM NZH; 80 mM SL); removal of the endothelium (NZH); or inhibitors of cyclooxygenase, lipoxygenase, cytochrome P-450 or antagonists of alpha-adrenergic, muscarinic, nicotinic, purinergic, or serotoninergic receptors. These results show that HV is an intrinsic feature of systemic VSM in cyclostomes and suggest that HV has been in the repertoire of VSM responses, since the origin of vertebrates. The exceptionally hardy HV in cyclostome DA may provide a useful model with which to examine both the phylogeny and mechanisms of this response.
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Affiliation(s)
- K R Olson
- Indiana University School of Medicine, South Bend Center for Medical Education, University of Notre Dame, Notre Dame, Indiana 46556, USA.
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Bedford JJ, Harper JL, Leader JP, Yancey PH, Smith RA. Betaine is the principal counteracting osmolyte in tissues of the elephant fish, Callorhincus millii (Elasmobranchii, Holocephali). Comp Biochem Physiol B Biochem Mol Biol 1998. [DOI: 10.1016/s0305-0491(98)00013-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Kirschner LB. Extrarenal Mechanisms in Hydromineral and Acid‐Base Regulation in Aquatic Vertebrates. Compr Physiol 1997. [DOI: 10.1002/cphy.cp130109] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Kinne RK. The role of organic osmolytes in osmoregulation: from bacteria to mammals. THE JOURNAL OF EXPERIMENTAL ZOOLOGY 1993; 265:346-55. [PMID: 8463791 DOI: 10.1002/jez.1402650403] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Cells of marine species are known to establish osmotic balance with their environment by adjusting the concentrations of organic osmolytes rather than inorganic osmolytes such as sodium, potassium, and chloride. These organic osmolytes fall into three classes: polyhydric alcohols such as sorbitol, amino acids and amino acid derivatives, and urea and trimethylamines. Substantial evidence is available for a central role of each of these classes in osmoregulation in marine species. In this chapter information on the importance of organic osmolytes is extended to a study of isolated mammalian kidney cells. The intracellular concentration of organic osmolytes in these cells responds dramatically to changes in the osmotic environment. The release of sorbitol following hypoosmotic exposure appears to be triggered by calcium, possibly via a mechanism involving membrane recycling. The summarized experiments provide a basis for further work in marine species.
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Affiliation(s)
- R K Kinne
- Max-Planck-Institut für Systemphysiologie, Dortmund, Germany
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Olson KR. 3 Blood and Extracellular Fluid Volume Regulation: Role of the Renin-Angiotensin System, Kallikrein-Kinin System, and Atrial Natriuretic Peptides. FISH PHYSIOLOGY 1992. [DOI: 10.1016/s1546-5098(08)60010-2] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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The free amino acids of muscle in the cephalochordate Branchiostoma, the cyclostome Myxine and some fishes. ACTA ACUST UNITED AC 1991. [DOI: 10.1016/0300-9629(91)90493-v] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Osmotic constituents of the blood plasma and parietal muscle of Scyliorhinus canicula (L.). ACTA ACUST UNITED AC 1989. [DOI: 10.1016/0300-9629(89)90504-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Elger M. The branchial circulation and the gill epithelia in the Atlantic hagfish, Myxine glutinosa L. ANATOMY AND EMBRYOLOGY 1987; 175:489-504. [PMID: 3578827 DOI: 10.1007/bf00309684] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The vessels of the branchial circulation of the Atlantic hagfish, Myxine glutinosa, and their relationship with the gill epithelia have been studied by light and electron microscopy. The inner surface of the pouch wall (containing the interconnected radial arteries) and the afferent and efferent unbranched portions (cavernous tissues) of the radially oriented gill folds are covered by a multilayered epithelium. The lamellar portion that is characterized by pillar cells is lined by a thin bilayered epithelium. The thin-walled sinusoid system is part of an arterio-venous circulation. This is demonstrated by the presence of arterio-venous anastomoses and by the connection to the peribranchial sinus. The sinusoid system has a close spatial relationship to the multilayered epithelium. The multilayered epithelium consists of pavement cells, cells of the medial layer and basal cells. Granulated cells are often found in the basal half of the epithelium. The pavement cells are characterized by large vesicles in close apposition to the apical plasma membrane. Ionocytes, which display a cytoplasmic tubular system that is continuous with the intercellular space, a high number of mitochondria, and small apical vesicles, are present. The occurence of the ionocytes in the afferent multilayered epithelium as well as the bilayered lamellar epithelium, the morphology of the ionocyte, and the absence of accessory cells is reminiscent of the freshwater teleost gill, and in part the elasmobranch gill, and is discussed in relation to osmo- and ion regulation.
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Mallatt J, Paulsen C. Gill ultrastructure of the Pacific hagfish Eptatretus stouti. THE AMERICAN JOURNAL OF ANATOMY 1986; 177:243-69. [PMID: 3788822 DOI: 10.1002/aja.1001770209] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
At the gross anatomical level, hagfish gills show unusual features not seen in any other fish gills. Our study was undertaken to determine if peculiarities also characterize the microscopic anatomy and ultrastructure of hagfish gills. To the contrary, branchial respiratory lamellae of Pacific hagfish were found to resemble the lamellae of lampreys, elasmobranchs, and teleosts, often down to the finest subcellular details. As in other fish, hagfish lamellae are lined by epithelium containing pavement cells with organelles indicative of a secretory function, basal cells showing undifferentiated cell features, and branchial ionocytes. The ionocytes are identical to chloride cells of teleosts in cytostructure, distribution, and abundance. There are pillar and marginal capillaries in hagfish gill lamellae. Pillar cells contain bundles of 5-nm microfilaments, and they associate with collagen columns as in other fish. Hagfish pillar cells do exhibit odd features, however: They cluster (groups of up to nine were seen), and their extracellular collagen columns are rarer than in other fish gills (averaging only two columns per three pillar cells). Other special features of hagfish gills are the following: lipid droplets and smooth endoplasmic reticulum are well developed in all cell types; pavement cells secrete a lipomucous product (stains with periodic acid-Schiff, Alcian blue, and Sudan black B); and goblet cells are absent. The presence of "chloride cells" in hagfish is puzzling, as hagfish body fluids are iso-osmotic to seawater and there is no need to osmoregulate for sodium chloride; the ionocytes contain carbonic anhydrase, suggesting a function in acid/base regulation.
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Robertson JD. The osmotic concentration of parietal muscle of the hagfish Myxine glutinosa L., including estimates of free and bound constituents. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. A, COMPARATIVE PHYSIOLOGY 1986; 84:751-7. [PMID: 2875844 DOI: 10.1016/0300-9629(86)90400-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The principal osmotic constituents of plasma and of muscle before and after ultracentrifugation have been determined. By analysing the muscle fluid and centrifuged muscle and determining their extracellular fluid (inulin space), ion-binding in the cells was estimated at Na 26%, K 0.3%, Ca 93%, Mg 24%, Cl 21% and P 10%. Muscle fluid was 4.9% (2.7-7.4%) hyperosmotic to plasma. This is discussed in relation to calculated osmolality of muscle and plasma.
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Bartels H. Assemblies of linear arrays of particles in the apical plasma membrane of mitochondria-rich cells in the gill epithelium of the Atlantic hagfish (Myxine glutinosa). Anat Rec (Hoboken) 1985; 211:229-38. [PMID: 3993977 DOI: 10.1002/ar.1092110302] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
In the gill epithelium of the Atlantic hagfish Myxine glutinosa a mitochondria-rich cell type is described which ultrastructurally resembles the chloride cells in other fish species. Freeze-fracture replicas reveal different supramolecular structures in the luminal plasma membrane and in the intracellular amplification (tubular system) of the basolateral plasma membrane of these mitochondria-rich cells. In the luminal plasma membrane ordered assemblies of particles and fibril-like elements are regularly found. On the P face, the assemblies are composed of up to 20 linear arrays of particles which are preferentially located in the microvillar membrane on which they show a helicoidal orientation. The arrays are formed by globular (diameter 8-9 nm) and rod-shaped (length 16-20 nm) particles, which occasionally are so tightly end-to-end attached that they generate fibril-like structures. The distances between adjacent arrays within an assembly measure 10-15 nm. On the E face complementary patterns of linear grooves are present. These assemblies have not previously been demonstrated in the freeze-fractured plasma membrane of branchial chloride cells. In the membrane of the tubular system, emerging from the basolateral plasma membrane of the mitochondria-rich cells, infrequently repeating rows of 7-8 nm particles are present in addition to randomly distributed globular particles (diameter 7-8 nm). Complementary patterns of grooves are present on the E face. These intramembranous structures resemble the repetitive elements which have been previously described in the tubular system of branchial chloride cells in euryhaline teleosts and the subunits of which are considered to be the sites of ion pumps.
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Robertson JD. The composition of blood plasma and parietal muscle of oslo fjord eels [Anguilla anguilla (L.)] and the river lamprey [Lampetra fluviatilis (L.)]. ACTA ACUST UNITED AC 1984. [DOI: 10.1016/0300-9629(84)90208-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Burton RF. Cell composition as assessed from osmolality and concentrations of sodium, potassium and chloride: total contributions of other substances to osmolality and charge balance. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. A, COMPARATIVE PHYSIOLOGY 1983; 76:161-5. [PMID: 6138182 DOI: 10.1016/0300-9629(83)90308-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
From published data for various tissues on intracellular Na, K and Cl were calculated the net anionic charge on all other substances present and also the total contribution of these to osmolality, assuming osmotic equilibrium with extracellular fluid. These parameters were compared for muscle and nerve of animals differing widely in osmolality and also for other mammalian cells. Cell volume regulation in some euryhaline species was considered; it is only partly due to ninhydrin-positive materials. In sheep mammary glands K seems to be sequestered with lactose and anion. Changes in mammalian muscle due to adrenalectomy, hypophysectomy, K deficiency, myotonia, acid-base imbalance and treatment with deoxycorticosterone or insulin were discussed.
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Burton RF. The composition of animal cells: solutes contributing to osmotic pressure and charge balance. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. B, COMPARATIVE BIOCHEMISTRY 1983; 76:663-71. [PMID: 6362972 DOI: 10.1016/0305-0491(83)90375-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The cytoplasmic solutes of vertebrates and invertebrates, other than Na, K and Cl, are surveyed in relation to their influence on ionic regulation through osmolality and charge balance. The most abundant include MgATP, phosphagens, amino acids, various other nitrogen and phosphorus compounds and sometimes anaerobic end products and antifreeze agents. Differences in muscle osmolality, e.g. between marine and non-marine animals, affect mainly nitrogenous solutes of no net charge, such as certain amino acids, taurine, betaine, trimethylamine oxide and urea. The high osmolality of axoplasm in marine invertebrates is due more to anions such as aspartate, glutamate and isethionate.
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Bedford JJ. The composition of the fluid compartments of two chondrichthyans, Callorhyncus millii and Squalus acanthias. ACTA ACUST UNITED AC 1983. [DOI: 10.1016/0300-9629(83)90295-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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