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Fehsenfeld S, Yoon GR, Quijada-Rodriguez AR, Kandachi-Toujas H, Calosi P, Breton S, Weihrauch D. Short-term exposure to high pCO 2 leads to decreased branchial cytochrome C oxidase activity in the presence of octopamine in a decapod. Comp Biochem Physiol A Mol Integr Physiol 2024; 291:111603. [PMID: 38346534 DOI: 10.1016/j.cbpa.2024.111603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 02/07/2024] [Accepted: 02/08/2024] [Indexed: 02/18/2024]
Abstract
In a recent mechanistic study, octopamine was shown to promote proton transport over the branchial epithelium in green crabs, Carcinus maenas. Here, we follow up on this finding by investigating the involvement of octopamine in an environmental and physiological context that challenges acid-base homeostasis, the response to short-term high pCO2 exposure (400 Pa) in a brackish water environment. We show that hyperregulating green crabs experienced a respiratory acidosis as early as 6 h of exposure to hypercapnia, with a rise in hemolymph pCO2 accompanied by a simultaneous drop of hemolymph pH. The slightly delayed increase in hemolymph HCO3- observed after 24 h helped to restore hemolymph pH to initial values by 48 h. Circulating levels of the biogenic amine octopamine were significantly higher in short-term high pCO2 exposed crabs compared to control crabs after 48 h. Whole animal metabolic rates, intracellular levels of octopamine and cAMP, as well as branchial mitochondrial enzyme activities for complex I + III and citrate synthase were unchanged in posterior gill #7 after 48 h of hypercapnia. However, application of octopamine in gill respirometry experiments suppressed branchial metabolic rate in posterior gills of short-term high pCO2 exposed animals. Furthermore, branchial enzyme activity of cytochrome C oxidase decreased in high pCO2 exposed crabs after 48 h. Our results indicate that hyperregulating green crabs are capable of quickly counteracting a hypercapnia-induced respiratory acidosis. The role of octopamine in the acclimation of green crabs to short-term hypercapnia seems to entail the alteration of branchial metabolic pathways, possibly targeting mitochondrial cytochrome C in the gill. Our findings help advancing our current limited understanding of endocrine components in hypercapnia acclimation. SUMMARY STATEMENT: Acid-base compensation upon short-term high pCO2 exposure in hyperregulating green crabs started after 6 h and was accomplished by 48 h with the involvement of the biogenic amine octopamine, accumulation of hemolymph HCO3-, and regulation of mitochondrial complex IV (cytochrome C oxidase).
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Affiliation(s)
- Sandra Fehsenfeld
- Laboratoire de Physiologie Écologique et Évolutive Marine, Département de Biologie, Chimie et Géographie, Université du Québec à Rimouski, Rimouski, Canada; Department of Biological Sciences, University of Manitoba, Winnipeg, Canada.
| | - Gwangseok R Yoon
- Department of Biological Sciences, University of Manitoba, Winnipeg, Canada; Department of Biological Sciences, University of Toronto Scarborough, Toronto, Canada
| | - Alex R Quijada-Rodriguez
- Department of Biological Sciences, University of Manitoba, Winnipeg, Canada; Department of Biology, Wilfrid Laurier University, Waterloo, Canada
| | - Haluka Kandachi-Toujas
- Laboratoire de Physiologie Écologique et Évolutive Marine, Département de Biologie, Chimie et Géographie, Université du Québec à Rimouski, Rimouski, Canada
| | - Piero Calosi
- Laboratoire de Physiologie Écologique et Évolutive Marine, Département de Biologie, Chimie et Géographie, Université du Québec à Rimouski, Rimouski, Canada
| | - Sophie Breton
- Département de Sciences Biologiques, Université de Montréal, Montréal, Canada
| | - Dirk Weihrauch
- Department of Biological Sciences, University of Manitoba, Winnipeg, Canada
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Editorial on Adaptations of nutrient supply organs that fuel the fire of life. Comp Biochem Physiol A Mol Integr Physiol 2023; 278:111371. [PMID: 36646307 DOI: 10.1016/j.cbpa.2023.111371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Wood CM. Exercise and emersion in air and recovery in seawater in the green crab (Carcinus maenas): Effects on nitrogenous wastes and branchial chamber fluid chemistry. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2023; 339:163-179. [PMID: 36369453 DOI: 10.1002/jez.2669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 09/25/2022] [Accepted: 10/07/2022] [Indexed: 11/13/2022]
Abstract
At low tide, the green crab, which is capable of breathing air, may leave the water and walk on the foreshore, carrying branchial chamber fluid (BCF). N-waste metabolism was examined in crabs at rest in seawater (32 ppt, 13°C), and during 18-h recovery in seawater after 1 h of exhaustive exercise (0.25 BL s-1 ) on a treadmill in air (20°C-23°C), or 1 h of quiet emersion in air. Measurements were made in parallel to O2 consumption (ṀO2 ), acid-base, cardio-respiratory, and ion data reported previously. At rest, the ammonia-N excretion rate (ṀAmm = 44 µmol-N kg-1 h-1 ) and ammonia quotient (AQ; ṀAmm /ṀO2 = 0.088) were low for a carnivore. Immediately after exercise and return to seawater, ṀAmm increased by 65-fold above control rates. After emersion alone and return to seawater, ṀAmm increased by 17-fold. These ammonia-N bursts were greater, but transient relative to longer-lasting elevations in ṀO2 , resulting in temporal disturbances of AQ. Intermittent excretion of urea-N and urate-N at rest and during recovery indicated the metabolic importance of these N-wastes. Hemolymph glutamate, glutamine, and PNH3 did not change. Hemolymph ammonia-N, urea-N, and urate-N concentrations increased after exercise and more moderately after emersion, with urate-N exhibiting the largest absolute increments, and urea-N the longest-lasting elevations. All three N-wastes were present in the BCF, with ammonia-N and PNH3 far above hemolymph levels even at rest. BCF volume declined by 34% postemersion and 77% postexercise, with little change in osmolality but large increases in ammonia-N concentrations. Neither rapid flushing of stored BCF nor clearance of hemolymph ammonia-N could explain the surges in ṀAmm after return to seawater.
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Affiliation(s)
- Chris M Wood
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada.,Bamfield Marine Sciences Centre, Bamfield, British Columbia, Canada.,Department of Biology, McMaster University, Hamilton, Ontario, Canada
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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] [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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Nash MT, Quijada-Rodriguez AR, Allen GJP, Wilson JM, Weihrauch D. Characterization of 3 different types of aquaporins in Carcinus maenas and their potential role in osmoregulation. Comp Biochem Physiol A Mol Integr Physiol 2022; 272:111281. [PMID: 35902004 DOI: 10.1016/j.cbpa.2022.111281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 07/21/2022] [Accepted: 07/21/2022] [Indexed: 11/18/2022]
Abstract
Intertidal crustaceans like Carcinus maenas shift between an osmoconforming and osmoregulating state when inhabiting full-strength seawater and dilute environments, respectively. While the bodily fluids and environment of marine osmoconformers are approximately isosmotic, osmoregulating crabs inhabiting dilute environments maintain their bodily fluid osmolality above that of their environment by actively absorbing and retaining osmolytes (e.g., Na+, Cl-, urea) while eliminating excess water. Few studies have investigated the role of aquaporins (AQPs) in the osmoregulatory organs of crustaceans, especially within brachyuran species. In the current study, three different aquaporins were identified within a transcriptome of C. maenas, including a classical AQP (CmAQP1), an aquaglyceroporin (CmGLP1), and a big-brain protein (CmBIB1), all of which are expressed in the gills and the antennal glands. Functional expression of these aquaporins confirmed water transport capabilities for CmAQP1, CmGLP1, but not for CmBIB1, while CmGLP1 also transported urea. Higher relative CmAQP1 mRNA expression within tissues of osmoconforming crabs suggests the apical/sub-apically localized channel attenuates osmotic gradients created by non-osmoregulatory processes while its downregulation in dilute media reduces the water permeability of tissues to facilitate osmoregulation. Although hemolymph urea concentrations rose upon exposure to brackish water, urea was not detected in the final urine. Due to its urea-transport capabilities, CmGLP1 is hypothesized to be involved in a urea retention mechanism believed to be involved in the production of diluted urine. Overall, these results suggest that AQPs are involved in osmoregulation and provide a basis for future mechanistic studies investigating the role of AQPs in volume regulation in crustaceans.
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Affiliation(s)
- M T Nash
- Biological Sciences, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | | | - G J P Allen
- Biological Sciences, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - J M Wilson
- Biology, Wilfrid Laurier University, Waterloo, Canada
| | - D Weihrauch
- Biological Sciences, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada.
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Country MW. Crustacean stomachs are crabby, but not caustic. J Exp Biol 2022. [DOI: 10.1242/jeb.243487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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