1
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Pedersen SHF. Acid-base transporters in the context of tumor heterogeneity. Pflugers Arch 2024; 476:689-701. [PMID: 38332178 DOI: 10.1007/s00424-024-02918-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 01/20/2024] [Accepted: 01/29/2024] [Indexed: 02/10/2024]
Abstract
The copious metabolic acid production and -extrusion by cancer cells render poorly vascularized regions of solid tumors highly acidic. A growing list of proton - and bicarbonate transporters has been suggested to contribute to net acid extrusion from cancer cells, and/or been shown to be dysregulated and favor malignant development in various cancers. The great majority of these roles have been studied at the level of the cancer cells. However, recent advances in understanding of the cellular and physicochemical heterogeneity of solid tumors both enable and necessitate a reexamination of the regulation and roles of acid-base transporters in such malignancies. This review will briefly summarize the state-of-the-art, with a focus on the SLC9A and SLC4A families, for which most evidence is available. This is followed by a discussion of key concepts and open questions arising from recent insights and of the challenges that need to be tackled to address them. Finally, opportunities and challenges in therapeutic targeting of the acid-base transportome in cancers will be addressed.
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Affiliation(s)
- Stine Helene Falsig Pedersen
- Section for Cell Biology and Physiology, Department of Biology, Faculty of Science, University of Copenhagen, Universitetsparken 13, 2100, Copenhagen, Denmark.
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2
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Shartau RB, Shu J, Baker DW. The role of salinity in recovery of white sturgeon ( Acipenser transmontanus) from stimulated angling stress. Conserv Physiol 2023; 11:coad009. [PMID: 36950376 PMCID: PMC10025808 DOI: 10.1093/conphys/coad009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 02/01/2023] [Accepted: 02/27/2023] [Indexed: 06/18/2023]
Abstract
White sturgeon (Acipenser transmontanus) in the Lower Fraser River are the focus of a catch-and-release angling fishery in British Columbia, Canada. However, the lower region of the catch area includes areas where tidal waters invade, and the consequence of salinity levels on recovery from an angling challenge are not characterized in sturgeon, despite theoretical implications of its import. We acclimated white sturgeon to various salinities (0, 10 and 20‰ (parts per thousand)) to investigate the effects of acclimation on recovery from stimulated angling stress that was induced through manual chasing. This challenge elicited the traditional physiological responses such as ion homeostasis disturbance, increases in secondary stress indicators and metabolic acidosis; however, environmental salinity altered the timing of recovery in some of the parameters measured. In addition, the severity of the intracellular pH disturbance in both heart and red blood cell seemed to be mediated in fresh water, yet the recovery pattern of plasma chloride and bicarbonate ions seemed to be facilitated by higher salinity. In general, responses were similar but not identical, leading us to conclude that the role of salinity on recovery from exercise is complex but not insignificant. Salinity may be important to behaviours exhibited by white sturgeon (such as migrations) in their respective saline environments, but less so around the impact of an angling stressor. Further exploration of this response may provide insight on whether the current tidal boundaries for angling white sturgeon are appropriate.
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Affiliation(s)
- Ryan B Shartau
- Corresponding author: Department of Biology, The University of Texas at Tyler, 3900 University Blvd., Tyler, Texas, United States 75799.
| | - Jacelyn Shu
- Department of Zoology, University of British Columbia, 4200 - 6270 University Blvd., Vancouver, British Columbia, Canada V6T 1Z4
| | - Daniel W Baker
- Department of Fisheries and Aquaculture, Vancouver Island University, 900 Fifth Street, Nanaimo, British Columbia, Canada, V9R 5S5
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3
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Dal Pont G, Po B, Wang J, Wood CM. How the green crab Carcinus maenas copes physiologically with a range of salinities. J Comp Physiol B 2022; 192:683-699. [PMID: 36040508 DOI: 10.1007/s00360-022-01458-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 08/07/2022] [Accepted: 08/18/2022] [Indexed: 10/14/2022]
Abstract
To evaluate the physiological ability to adjust to environmental variations of salinity, Carcinus maenas were maintained in 10, 20, 32 (control), 40, and 50 ppt (13.8 ± 0.6 °C) for 7 days. Closed respirometry systems were used to evaluate oxygen consumption ([Formula: see text]), ammonia excretion (Jamm), urea-N excretion (Jurea-N) and diffusive water fluxes (with 3H2O). Ions, osmolality, metabolites, and acid-base status were determined in the hemolymph and seawater, and transepithelial potential (TEP) was measured. At the lowest salinity, there were marked increases in [Formula: see text] and Jamm, greater reliance on N-containing fuels to support aerobic metabolism, and a state of internal metabolic alkalosis (increased [HCO3-]) despite lower seawater pH. At higher salinities, an activation of anaerobic metabolism and a state of metabolic acidosis (decreased [HCO3-] and increased [lactate]), in combination with respiratory compensation (decreased PCO2), were detected. TEP became more negative with decreasing salinity. Osmoregulation and osmoconformation occurred at low and high salinities, respectively, with complex patterns in individual ions; hemolymph [Mg2+] was particularly well regulated at levels well below the external seawater at all salinities. Diffusive water flux rates increased at higher salinities. Our results show that C. maenas exhibits wide plasticity of physiological responses when acclimated to different salinities and tolerates substantial disturbances of physiological parameters, illustrating that this species is well adapted to invade and survive in diverse habitats.
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Affiliation(s)
- Giorgi Dal Pont
- Department of Zoology, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.,Bamfield Marine Sciences Centre, Bamfield, BC, V0R 1B0, Canada.,Integrated Group for Aquaculture and Environmental Studies, Department of Animal Science, Federal University of Paraná, Curitiba, Paraná, 83035-050, Brazil
| | - Beverly Po
- Department of Zoology, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.,Bamfield Marine Sciences Centre, Bamfield, BC, V0R 1B0, Canada
| | - Jun Wang
- Department of Zoology, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.,Bamfield Marine Sciences Centre, Bamfield, BC, V0R 1B0, Canada.,College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China
| | - Chris M Wood
- Department of Zoology, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada. .,Bamfield Marine Sciences Centre, Bamfield, BC, V0R 1B0, Canada.
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4
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Petersen I, Chang WWJ, Hu MY. Na+/H+ exchangers differentially contribute to midgut fluid sodium and proton concentration in the sea urchin larva. J Exp Biol 2021; 224:239542. [PMID: 34424985 DOI: 10.1242/jeb.240705] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 02/24/2021] [Indexed: 11/20/2022]
Abstract
Regulation of ionic composition and pH is a requisite of all digestive systems in the animal kingdom. Larval stages of the marine superphylum Ambulacraria, including echinoderms and hemichordates, were demonstrated to have highly alkaline conditions in their midgut with the underlying epithelial transport mechanisms being largely unknown. Using ion-selective microelectrodes, the present study demonstrated that pluteus larvae of the purple sea urchin have highly alkaline pH (pH ∼9) and low [Na+] (∼120 mmol l-1) in their midgut fluids, compared with the ionic composition of the surrounding seawater. We pharmacologically investigated the role of Na+/H+ exchangers (NHE) in intracellular pH regulation and midgut proton and sodium maintenance using the NHE inhibitor 5-(n-ethyl-n-isopropyl)amiloride (EIPA). Basolateral EIPA application decreased midgut pH while luminal application via micro-injections increased midgut [Na+], without affecting pH. Immunohistochemical analysis demonstrated a luminal localization of NHE-2 (SpSlc9a2) in the midgut epithelium. Specific knockdown of spslc9a2 using Vivo-Morpholinos led to an increase in midgut [Na+] without affecting pH. Acute acidification experiments in combination with quantitative PCR analysis and measurements of midgut pH and [Na+] identified two other NHE isoforms, Spslc9a7 and SpSlc9a8, which potentially contribute to the regulation of [Na+] and pH in midgut fluids. This work provides new insights into ion regulatory mechanisms in the midgut epithelium of sea urchin larvae. The involvement of NHEs in regulating pH and Na+ balance in midgut fluids shows conserved features of insect and vertebrate digestive systems and may contribute to the ability of sea urchin larvae to cope with changes in seawater pH.
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Affiliation(s)
- Inga Petersen
- Institute of Physiology, Christian-Albrechts University of Kiel, Hermann-Rodewaldstraße 5, 24118 Kiel, Germany
| | - William W J Chang
- Institute of Physiology, Christian-Albrechts University of Kiel, Hermann-Rodewaldstraße 5, 24118 Kiel, Germany
| | - Marian Y Hu
- Institute of Physiology, Christian-Albrechts University of Kiel, Hermann-Rodewaldstraße 5, 24118 Kiel, Germany
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5
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Barnawi EA, Doherty JE, Ferreira PG, Wilson JM. Extra-gastric expression of the proton pump H +/K +-ATPase in the gills and kidney of the teleost Oreochromis niloticus. J Exp Biol 2020; 223:jeb214890. [PMID: 32611790 DOI: 10.1242/jeb.214890] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 06/26/2020] [Indexed: 12/12/2022]
Abstract
Potassium regulation is essential for the proper functioning of excitable tissues in vertebrates. The H+/K+-ATPase (HKA), which is composed of the HKα1 (gene: atp4a) and HKβ (gene: atp4b) subunits, has an established role in potassium and acid-base regulation in mammals and is well known for its role in gastric acidification. However, the role of HKA in extra-gastric organs such as the gill and kidney is less clear, especially in fishes. In the present study in Nile tilapia, Oreochromis niloticus, uptake of the K+ surrogate flux marker rubidium (Rb+) was demonstrated in vivo; however, this uptake was not inhibited with omeprazole, a potent inhibitor of the gastric HKA. This contrasts with gill and kidney ex vivo preparations, where tissue Rb+ uptake was significantly inhibited by omeprazole and SCH28080, another gastric HKA inhibitor. The cellular localization of this pump in both the gill and kidney was demonstrated using immunohistochemical techniques with custom-made antibodies specific for Atp4a and Atp4b. Antibodies against the two subunits showed the same apical ionocyte distribution pattern in the gill and collecting tubules/ducts in the kidney. Atp4a antibody specificity was confirmed by western blotting. RT-PCT was used to confirm the expression of both subunits in the gill and kidney. Taken together, these results indicate for the first time K+ (Rb+) uptake in O. niloticus and that HKA is implicated, as shown through the ex vivo uptake inhibition by omeprazole and SCH28080, verifying a role for HKA in K+ absorption in the gill's ionocytes and collecting tubule/duct segments of the kidney.
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Affiliation(s)
- Ebtesam Ali Barnawi
- Department of Biology, Wilfrid Laurier University, Waterloo, ON, Canada, N2L 3C5
| | - Justine E Doherty
- Department of Biology, Wilfrid Laurier University, Waterloo, ON, Canada, N2L 3C5
| | | | - Jonathan M Wilson
- Department of Biology, Wilfrid Laurier University, Waterloo, ON, Canada, N2L 3C5
- Molecular Physiology, Centro Interdisciplinar de Investigação Marinha e Ambiental, 4450-208 Matosinhos, Portugal
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6
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Shartau RB, Baker DW, Harter TS, Aboagye DL, Allen PJ, Val AL, Crossley DA, Kohl ZF, Hedrick MS, Damsgaard C, Brauner CJ. Preferential intracellular pH regulation is a common trait amongst fishes exposed to high environmental CO 2. J Exp Biol 2020; 223:jeb208868. [PMID: 32127382 DOI: 10.1242/jeb.208868] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 02/25/2020] [Indexed: 12/13/2022]
Abstract
Acute (<96 h) exposure to elevated environmental CO2 (hypercarbia) induces a pH disturbance in fishes that is often compensated by concurrent recovery of intracellular and extracellular pH (pHi and pHe, respectively; coupled pH regulation). However, coupled pH regulation may be limited at CO2 partial pressure (PCO2 ) tensions far below levels that some fishes naturally encounter. Previously, four hypercarbia-tolerant fishes had been shown to completely and rapidly regulate heart, brain, liver and white muscle pHi during acute exposure to >4 kPa PCO2 (preferential pHi regulation) before pHe compensation was observed. Here, we test the hypothesis that preferential pHi regulation is a widespread strategy of acid-base regulation among fish by measuring pHi regulation in 10 different fish species that are broadly phylogenetically separated, spanning six orders, eight families and 10 genera. Contrary to previous views, we show that preferential pHi regulation is the most common strategy for acid-base regulation within these fishes during exposure to severe acute hypercarbia and that this strategy is associated with increased hypercarbia tolerance. This suggests that preferential pHi regulation may confer tolerance to the respiratory acidosis associated with hypercarbia, and we propose that it is an exaptation that facilitated key evolutionary transitions in vertebrate evolution, such as the evolution of air breathing.
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Affiliation(s)
- R B Shartau
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
| | - D W Baker
- Department of Fisheries and Aquaculture, Vancouver Island University, Nanaimo, BC, Canada V9R 5S5
| | - T S Harter
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
| | - D L Aboagye
- Department of Wildlife, Fisheries and Aquaculture, Mississippi State University, Starkville, MS 39759, USA
| | - P J Allen
- Department of Wildlife, Fisheries and Aquaculture, Mississippi State University, Starkville, MS 39759, USA
| | - A L Val
- Laboratory of Ecophysiology and Molecular Evolution, Brazilian National Institute for Research of the Amazon (INPA), Manaus, AM CEP 69080-971, Brazil
| | - D A Crossley
- Department of Biological Sciences, University of North Texas, Denton, TX 76203-5017, USA
| | - Z F Kohl
- Department of Biological Sciences, University of North Texas, Denton, TX 76203-5017, USA
| | - M S Hedrick
- Department of Biological Sciences, California State University, East Bay, CA 94542, USA
| | - C Damsgaard
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
| | - C J Brauner
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
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7
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Abstract
The regulation of vertebrate acid-base balance during acute episodes of elevated internal PCO2 is typically characterized by extracellular pH (pHe) regulation. Changes in pHe are associated with qualitatively similar changes in intracellular tissue pH (pHi) as the two are typically coupled, referred to as 'coupled pH regulation'. However, not all vertebrates rely on coupled pH regulation; instead, some preferentially regulate pHi against severe and maintained reductions in pHe Preferential pHi regulation has been identified in several adult fish species and an aquatic amphibian, but never in adult amniotes. Recently, common snapping turtles were observed to preferentially regulate pHi during development; the pattern of acid-base regulation in these species shifts from preferential pHi regulation in embryos to coupled pH regulation in adults. In this Commentary, we discuss the hypothesis that preferential pHi regulation may be a general strategy employed by vertebrate embryos in order to maintain acid-base homeostasis during severe acute acid-base disturbances. In adult vertebrates, the retention or loss of preferential pHi regulation may depend on selection pressures associated with the environment inhabited and/or the severity of acid-base regulatory challenges to which they are exposed. We also consider the idea that the retention of preferential pHi regulation into adulthood may have been a key event in vertebrate evolution, with implications for the invasion of freshwater habitats, the evolution of air breathing and the transition of vertebrates from water to land.
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Affiliation(s)
- Ryan B Shartau
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada, V6T 1Z4
| | - Daniel W Baker
- Department of Fisheries and Aquaculture, Vancouver Island University, Nanaimo, British Columbia, Canada, V9R 5S5
| | - Dane A Crossley
- Department of Biological Sciences, University of North Texas, Denton, TX 76203-5017, USA
| | - Colin J Brauner
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada, V6T 1Z4
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8
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Shartau RB, Baker DW, Brauner CJ. White sturgeon (Acipenser transmontanus) acid-base regulation differs in response to different types of acidoses. J Comp Physiol B 2017; 187:985-94. [PMID: 28283796 DOI: 10.1007/s00360-017-1065-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 02/02/2017] [Accepted: 02/09/2017] [Indexed: 10/20/2022]
Abstract
White sturgeon (Acipenser transmontanus) completely protect intracellular tissue pH (pHi) despite large reductions in extracellular (blood) pH (pHe), termed preferential pHi regulation, in response to elevated environmental PCO2 (hypercarbia) and in general appear to be relatively resilient to stressors. Preferential pHi regulation is thought to be associated with hypercarbia tolerance in general, but has also recently been observed to protect pHi against metabolic acidoses induced by exhaustive exercise and anoxia in a tropical air breathing catfish. We hypothesized that preferential pHi regulation may also be a general strategy of acid-base regulation in sturgeon. To address this hypothesis, severe acidoses were imposed to reduce pHe, and the presence or absence of preferential pHi regulation was assessed in red blood cells (RBC), heart, brain, liver and white muscle. A respiratory acidosis was imposed using hyperoxia, while metabolic acidoses were induced by exhaustive exercise, anoxia or air exposure. Reductions in pHe occurred following hyperoxia (0.15 units), exhaustive exercise (0.30 units), anoxia (0.10 units) and air exposure (0.35 units); all acidoses reduced RBC pHi. Following hyperoxia, heart, brain and liver pHi were preferentially regulated against the reduction in pHe, similar to hypercarbia exposure. Following all metabolic acidoses heart pHi was protected and brain pHi remained unchanged following exhaustive exercise and air exposure, however, brain pHi was reduced following anoxia. Liver and white muscle pHi were reduced following all metabolic acidoses. These results suggest preferential pHi regulation may be a general strategy during respiratory acidoses but during metabolic acidoses, the response differs between source of acidoses and tissues.
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9
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Hannan KD, Jeffrey JD, Hasler CT, Suski CD. Physiological responses of three species of unionid mussels to intermittent exposure to elevated carbon dioxide. Conserv Physiol 2016; 4:cow066. [PMID: 28066552 PMCID: PMC5196031 DOI: 10.1093/conphys/cow066] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Revised: 10/27/2016] [Accepted: 11/16/2016] [Indexed: 06/06/2023]
Abstract
Freshwater systems are at risk owing to increasing carbon dioxide (CO2) levels, and one of the possible reasons for these elevations is the deployment of non-physical fish barriers to prevent invasive fish movements. Carbon dioxide barriers have the potential to create short, chronic and intermittent exposures of CO2 for surrounding freshwater biota. Although intermittent exposures to a stressor may be more ecologically relevant, the majority of laboratory tests use chronic or short-term time periods to determine how organisms will respond to an environmental stressor. Measurements of the physiological responses of three species of unionid mussel, giant floaters (Pyganodon grandis), threeridge (Amblema plicata) and plain pocketbook (Lampsilis cardium), exposed to control pCO2 (~1000 µatm) or intermittent conditions of pCO2 (ranging from ~1000 to ~55 000 µatm) 12 times per day over a 28 day period were gathered. There was no indication of recovery in the physiological responses of mussels between applications of CO2, suggesting that the recovery time between CO2 pulses (1.5 h) was not sufficient for recovery from the CO2 exposure period (0.5 h). Observations of acid-base and stress responses were consistent with what has been observed in chronic studies of freshwater mussels exposed to elevated pCO2 (i.e. elevations in HCO3-, Ca2+, Na+ and glucose, and decreases in Mg2+ and Cl-). However, species differences were observed across almost all variables measured, which emphasizes the need for multispecies studies.
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Affiliation(s)
- Kelly D Hannan
- Department of Natural Resources and Environmental Science, University of Illinois at Urbana-Champaign, 1102 South Goodwin Avenue, Urbana, IL 61801, USA
| | - Jennifer D Jeffrey
- Department of Natural Resources and Environmental Science, University of Illinois at Urbana-Champaign, 1102 South Goodwin Avenue, Urbana, IL 61801, USA
| | - Caleb T Hasler
- Department of Natural Resources and Environmental Science, University of Illinois at Urbana-Champaign, 1102 South Goodwin Avenue, Urbana, IL 61801, USA
| | - Cory D Suski
- Department of Natural Resources and Environmental Science, University of Illinois at Urbana-Champaign, 1102 South Goodwin Avenue, Urbana, IL 61801, USA
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10
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Thiel D, Hugenschütt M, Meyer H, Paululat A, Quijada-Rodriguez AR, Purschke G, Weihrauch D. Ammonia excretion in the marine polychaete Eurythoe complanata (Annelida). ACTA ACUST UNITED AC 2016; 220:425-436. [PMID: 27852754 DOI: 10.1242/jeb.145615] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 11/11/2016] [Indexed: 12/31/2022]
Abstract
Ammonia is a toxic waste product from protein metabolism and needs to be either converted into less toxic molecules or, in the case of fish and aquatic invertebrates, excreted directly as is. In contrast to fish, very little is known regarding the ammonia excretion mechanism and the participating excretory organs in marine invertebrates. In the current study, ammonia excretion in the marine burrowing polychaete Eurythoe complanata was investigated. As a potential site for excretion, the 100-200 µm long, 30-50 µm wide and up to 25 µm thick dentrically branched, well ventilated and vascularized branchiae (gills) were identified. In comparison to the main body, the branchiae showed considerably higher mRNA expression levels of Na+/K+-ATPase, V-type H+-ATPase, cytoplasmic carbonic anhydrase (CA-2), a Rhesus-like protein, and three different ammonia transporters (AMTs). Experiments on the intact organism revealed that ammonia excretion did not occur via apical ammonia trapping, but was regulated by a basolateral localized V-type H+-ATPase, carbonic anhydrase and intracellular cAMP levels. Interestingly, the V-type H+-ATPase seems to play a role in ammonia retention. A 1 week exposure to 1 mmol l-1 NH4Cl (HEA) did not cause a change in ammonia excretion rates, while the three branchial expressed AMTs showed a tendency to be down-regulated. This indicates a shift of function in the branchial ammonia excretion processes under these conditions.
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Affiliation(s)
- Daniel Thiel
- University of Osnabrück, Fachbereich Biologie, Department of Zoology, Osnabrück 49069, Germany
| | - Maja Hugenschütt
- University of Osnabrück, Fachbereich Biologie, Department of Zoology, Osnabrück 49069, Germany
| | - Heiko Meyer
- University of Osnabrück, Fachbereich Biologie, Department of Zoology, Osnabrück 49069, Germany
| | - Achim Paululat
- University of Osnabrück, Fachbereich Biologie, Department of Zoology, Osnabrück 49069, Germany
| | | | - Günter Purschke
- University of Osnabrück, Fachbereich Biologie, Department of Zoology, Osnabrück 49069, Germany
| | - Dirk Weihrauch
- University of Manitoba, Department of Biological Sciences, Winnipeg, Manitoba, Canada
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11
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Wäge J, Hardege JD, Larsson TA, Simakov O, Chapman EC, Arendt D, Rotchell JM. Effects of low seawater pH on the marine polychaete Platynereis dumerilii. Mar Pollut Bull 2015; 95:166-172. [PMID: 25913791 DOI: 10.1016/j.marpolbul.2015.04.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Revised: 03/26/2015] [Accepted: 04/11/2015] [Indexed: 06/04/2023]
Abstract
An important priority for any organism is to maintain internal cellular homeostasis including acid-base balance. Yet, the molecular level impacts of changing environmental conditions, such as low pH, remain uncharacterised. Herein, we isolate partial Na(+)/H(+)exchangers (NHE), carbonic anhydrase (CA), and calmodulin (CaM) genes from a polychaete, Platynereis dumerilii and investigate their relative expression in acidified seawater conditions. mRNA expression of NHE was significantly down-regulated after 1h and up-regulated after 7days under low pH treatment (pH 7.8), indicating changes in acid-base transport. Furthermore, the localisation of NHE expression was also altered. A trend of down regulation in CA after 1h was also observed, suggesting a shift in the CO2 and HCO3(-) balance. No change in CaM expression was detected after 7days exposure to acidified seawater. This study provides insight into the molecular level changes taking place following exposure to acidified seawater in a non-calcifying, ubiquitous, organism.
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Affiliation(s)
- Janine Wäge
- School of Biological, Biomedical and Environmental Sciences, University of Hull, Cottingham Road, Hull HU6 7RX, United Kingdom
| | - Jörg D Hardege
- School of Biological, Biomedical and Environmental Sciences, University of Hull, Cottingham Road, Hull HU6 7RX, United Kingdom
| | - Tomas A Larsson
- European Molecular Biology Laboratory, Heidelberg, Meyerhofstr. 1, 69117 Heidelberg, Germany
| | - Oleg Simakov
- European Molecular Biology Laboratory, Heidelberg, Meyerhofstr. 1, 69117 Heidelberg, Germany
| | - Emma C Chapman
- School of Biological, Biomedical and Environmental Sciences, University of Hull, Cottingham Road, Hull HU6 7RX, United Kingdom
| | - Detlev Arendt
- European Molecular Biology Laboratory, Heidelberg, Meyerhofstr. 1, 69117 Heidelberg, Germany
| | - Jeanette M Rotchell
- School of Biological, Biomedical and Environmental Sciences, University of Hull, Cottingham Road, Hull HU6 7RX, United Kingdom.
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12
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Moulin L, Grosjean P, Leblud J, Batigny A, Collard M, Dubois P. Long-term mesocosms study of the effects of ocean acidification on growth and physiology of the sea urchin Echinometra mathaei. Mar Environ Res 2015; 103:103-114. [PMID: 25490159 DOI: 10.1016/j.marenvres.2014.11.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Revised: 11/12/2014] [Accepted: 11/19/2014] [Indexed: 06/04/2023]
Abstract
Recent research on the impact of ocean acidification (OA) has highlighted that it is important to conduct long-term experiments including ecosystem interactions in order to better predict the possible effects of elevated pCO2. The goal of the present study was to assess the long-term impact of OA on a suite of physiological parameters of the sea urchin Echinometra mathaei in more realistic food conditions. A long-term experiment was conducted in mesocosms provided with an artificial reef in which the urchins principally fed on algae attached to the reef calcareous substrate. Contrasted pH conditions (pH 7.7 vs control) were established gradually over six months and then maintained for seven more months. Acid-base parameters of the coelomic fluid, growth and respiration rate were monitored throughout the experiment. Results indicate that E. mathaei should be able to regulate its extracellular pH at long-term, through bicarbonate compensation. We suggest that, within sea urchins species, the ability to accumulate bicarbonates is related to their phylogeny but also on the quantity and quality of available food. Growth, respiration rate and mechanical properties of the test were not affected. This ability to resist OA levels expected for 2100 at long-term could determine the future of coral reefs, particularly reefs where E. mathaei is the major bioeroder.
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Affiliation(s)
- Laure Moulin
- Laboratoire de Biologie Marine, Université Libre de Bruxelles, CP 160/15, Avenue F.D. Roosevelt 50, 1050 Bruxelles, Belgium; Laboratoire d'Ecologie Numérique des Milieux Aquatiques, Institut des Biosciences, Université de Mons, 23 Place du Parc, B7000 Mons, Belgium.
| | - Philippe Grosjean
- Laboratoire d'Ecologie Numérique des Milieux Aquatiques, Institut des Biosciences, Université de Mons, 23 Place du Parc, B7000 Mons, Belgium
| | - Julien Leblud
- Laboratoire d'Ecologie Numérique des Milieux Aquatiques, Institut des Biosciences, Université de Mons, 23 Place du Parc, B7000 Mons, Belgium
| | - Antoine Batigny
- Laboratoire d'Ecologie Numérique des Milieux Aquatiques, Institut des Biosciences, Université de Mons, 23 Place du Parc, B7000 Mons, Belgium
| | - Marie Collard
- Laboratoire de Biologie Marine, Université Libre de Bruxelles, CP 160/15, Avenue F.D. Roosevelt 50, 1050 Bruxelles, Belgium; Laboratory for Analytical, Environmental and Geo-Chemistry, Earth Systems Science Research Group, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Philippe Dubois
- Laboratoire de Biologie Marine, Université Libre de Bruxelles, CP 160/15, Avenue F.D. Roosevelt 50, 1050 Bruxelles, Belgium
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Collard M, Dery A, Dehairs F, Dubois P. Euechinoidea and Cidaroidea respond differently to ocean acidification. Comp Biochem Physiol A Mol Integr Physiol 2014; 174:45-55. [PMID: 24786105 DOI: 10.1016/j.cbpa.2014.04.011] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Revised: 03/24/2014] [Accepted: 04/23/2014] [Indexed: 11/27/2022]
Abstract
The impact of the chemical changes in the ocean waters due to the increasing atmospheric CO₂ depends on the ability of an organism to control extracellular pH. Among sea urchins, this seems specific to the Euechinoidea, sea urchins except Cidaroidea. However, Cidaroidea survived two ocean acidification periods: the Permian-Trias and the Cretaceous-Tertiary crises. We investigated the response of these two sea urchin groups to reduced seawater pH with the tropical cidaroid Eucidaris tribuloides, the sympatric euechinoid Tripneustes ventricosus and the temperate euechinoid Paracentrotus lividus. Both euechinoid showed a compensation of the coelomic fluid pH due to increased buffer capacity. This was linked to an increased concentration of DIC in the coelomic fluid and thus of bicarbonate ions (most probably originating from the surrounding seawater as isotopic signature of the carbon - δ¹³C - was similar). On the other hand, the cidaroid showed no changes within the coelomic fluid. Moreover, the δ¹³C of the coelomic fluid did not match that of the seawater and was not significantly different between the urchins from the different treatments. Feeding rate was not affected in any species. While euechinoids are able to regulate their extracellular acid-base balance, many questions are still unanswered on the costs of this capacity. On the contrary, cidaroids do not seem affected by a reduced seawater pH. Further investigations need to be undertaken to cover more species and physiological and metabolic parameters in order to determine if energy trade-offs occur and how this mechanism of compensation is distributed among sea urchins.
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Affiliation(s)
- Marie Collard
- Laboratoire de Biologie Marine, Université Libre de Bruxelles, 50 Avenue F.D. Roosevelt, B-1050 Brussels, Belgium; Analytical, Environmental and Geo-Chemistry, Earth Systems Science Research Group, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium.
| | - Aurélie Dery
- Laboratoire de Biologie Marine, Université Libre de Bruxelles, 50 Avenue F.D. Roosevelt, B-1050 Brussels, Belgium
| | - Frank Dehairs
- Analytical, Environmental and Geo-Chemistry, Earth Systems Science Research Group, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Philippe Dubois
- Laboratoire de Biologie Marine, Université Libre de Bruxelles, 50 Avenue F.D. Roosevelt, B-1050 Brussels, Belgium
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Hu MY, Casties I, Stumpp M, Ortega-Martinez O, Dupont S. Energy metabolism and regeneration are impaired by seawater acidification in the infaunal brittlestar Amphiura filiformis. ACTA ACUST UNITED AC 2014; 217:2411-21. [PMID: 24737772 DOI: 10.1242/jeb.100024] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Seawater acidification due to anthropogenic release of CO2 as well as the potential leakage of pure CO2 from sub-seabed carbon capture storage (CCS) sites may impose a serious threat to marine organisms. Although infaunal organisms can be expected to be particularly impacted by decreases in seawater pH, as a result of naturally acidified conditions in benthic habitats, information regarding physiological and behavioral responses is still scarce. Determination of PO2 and P(CO2) gradients within burrows of the brittlestar Amphiura filiformis during environmental hypercapnia demonstrated that besides hypoxic conditions, increases of environmental P(CO2) are additive to the already high P(CO2) (up to 0.08 kPa) within the burrows. In response to up to 4 weeks exposure to pH 7.3 (0.3 kPa P(CO2)) and pH 7.0 (0.6 kPa P(CO2)), metabolic rates of A. filiformis were significantly reduced in pH 7.0 treatments, accompanied by increased ammonium excretion rates. Gene expression analyses demonstrated significant reductions of acid-base (NBCe and AQP9) and metabolic (G6PDH, LDH) genes. Determination of extracellular acid-base status indicated an uncompensated acidosis in CO2-treated animals, which could explain the depressed metabolic rates. Metabolic depression is associated with a retraction of filter feeding arms into sediment burrows. Regeneration of lost arm tissues following traumatic amputation is associated with significant increases in metabolic rate, and hypercapnic conditions (pH 7.0, 0.6 kPa) dramatically reduce the metabolic scope for regeneration, reflected in an 80% reduction in regeneration rate. Thus, the present work demonstrates that elevated seawater P(CO2) significantly affects the environment and the physiology of infaunal organisms like A. filiformis.
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Affiliation(s)
- Marian Y Hu
- Department of Biological and Environmental Sciences, The Sven Lovén Centre for Marine Sciences, Kristineberg, University of Gothenburg, 45178 Fiskebäckskil, Sweden Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 115, Taiwan
| | - Isabel Casties
- Department of Biological and Environmental Sciences, The Sven Lovén Centre for Marine Sciences, Kristineberg, University of Gothenburg, 45178 Fiskebäckskil, Sweden
| | - Meike Stumpp
- Department of Biological and Environmental Sciences, The Sven Lovén Centre for Marine Sciences, Kristineberg, University of Gothenburg, 45178 Fiskebäckskil, Sweden Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 115, Taiwan
| | - Olga Ortega-Martinez
- Department of Biological and Environmental Sciences, The Sven Lovén Centre for Marine Sciences, Kristineberg, University of Gothenburg, 45178 Fiskebäckskil, Sweden
| | - Sam Dupont
- Department of Biological and Environmental Sciences, The Sven Lovén Centre for Marine Sciences, Kristineberg, University of Gothenburg, 45178 Fiskebäckskil, Sweden
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Collard M, Laitat K, Moulin L, Catarino AI, Grosjean P, Dubois P. Buffer capacity of the coelomic fluid in echinoderms. Comp Biochem Physiol A Mol Integr Physiol 2013; 166:199-206. [PMID: 23752123 DOI: 10.1016/j.cbpa.2013.06.002] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Revised: 05/31/2013] [Accepted: 06/01/2013] [Indexed: 11/28/2022]
Abstract
The increase in atmospheric CO2 due to anthropogenic activity results in an acidification of the surface waters of the oceans. The impact of these chemical changes depends on the considered organisms. In particular, it depends on the ability of the organism to control the pH of its inner fluids. Among echinoderms, this ability seems to differ significantly according to species or taxa. In the present paper, we investigated the buffer capacity of the coelomic fluid in different echinoderm taxa as well as factors modifying this capacity. Euechinoidea (sea urchins except Cidaroidea) present a very high buffer capacity of the coelomic fluid (from 0.8 to 1.8mmolkg(-1) SW above that of seawater), while Cidaroidea (other sea urchins), starfish and holothurians have a significantly lower one (from -0.1 to 0.4mmolkg(-1) SW compared to seawater). We hypothesize that this is linked to the more efficient gas exchange structures present in the three last taxa, whereas Euechinoidea evolved specific buffer systems to compensate lower gas exchange abilities. The constituents of the buffer capacity and the factors influencing it were investigated in the sea urchin Paracentrotus lividus and the starfish Asterias rubens. Buffer capacity is primarily due to the bicarbonate buffer system of seawater (representing about 63% for sea urchins and 92% for starfish). It is also partly due to coelomocytes present in the coelomic fluid (around 8% for both) and, in P. lividus only, a compound of an apparent size larger than 3kDa is involved (about 15%). Feeding increased the buffer capacity in P. lividus (to a difference with seawater of about 2.3mmolkg(-1) SW compared to unfed ones who showed a difference of about 0.5mmolkg(-1) SW) but not in A. rubens (difference with seawater of about 0.2 for both conditions). In P. lividus, decreased seawater pH induced an increase of the buffer capacity of individuals maintained at pH7.7 to about twice that of the control individuals and, for those at pH7.4, about three times. This allowed a partial compensation of the coelomic fluid pH for individuals maintained at pH7.7 but not for those at pH7.4.
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Affiliation(s)
- Marie Collard
- Laboratoire de Biologie Marine, Université Libre de Bruxelles, 50 avenue F.D. Roosevelt, B-1050 Brussels, Belgium.
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