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Sadauskas-Henrique H, Smith DS, Val AL, Wood CM. Physicochemical properties of the dissolved organic carbon can lead to different physiological responses of zebrafish (Danio rerio) under neutral and acidic conditions. J Exp Zool A Ecol Integr Physiol 2021; 335:864-878. [PMID: 34435751 DOI: 10.1002/jez.2537] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 07/28/2021] [Accepted: 08/02/2021] [Indexed: 11/11/2022]
Abstract
Previous studies have suggested that the capacity of natural dissolved organic carbon (DOC) molecules to interact with biological membranes is associated with their aromaticity (SAC340 ); origin (allochthonous versus autochthonous, FI); molecular weight (Abs254/365 ); and relative fluorescence of DOC moieties (PARAFAC analysis). These interactions may be especially important when fish are challenged by acidic waters, which are known to inhibit the active uptake of Na+ and Cl- , while stimulating diffusive ion losses in freshwater fishes. Therefore, zebrafish were acclimated (7 days, pH 7.0) to five natural DOC sources (10 mg C/L), two from the Amazon Basin and three from Canada, together with a "no-added DOC" control. After the acclimation, fish were challenged by exposure to acidic water (pH 4.0) for 3 h. Osmoregulatory parameters were measured at pH 7.0 and 4.0. Acclimation to the five DOC sources did not disturb Na+ , Cl- and ammonia net fluxes, but resulted in differential elevations in Na+ , K+ ATPase and v-type H+ ATPase activities in fish at pH 7.0. However, after transfer to pH.4.0, the control fish exhibited rapid increases in both enzymes. In contrast the DOC- acclimated animals exhibited unchanged (Na+ , K+ ATPase) or differentially increased (v-type H+ ATPase) activities. Na+ , Cl- and ammonia net fluxes remained unchanged in the control fish, but were differentially elevated in most of the DOC treatments at pH 4.0, relative to the same DOC treatments at pH 7.0. Correlations between the osmoregulatory data the DOCs properties highlight that the DOC properties drive different effects on gill physiology.
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Affiliation(s)
- Helen Sadauskas-Henrique
- Laboratory of Ecophysiology and Molecular Evolution, Brazilian National Institute for Research of the Amazon, Manaus, AM, Brazil.,Universidade Santa Cecília (Unisanta), Santos, SP, Brazil
| | - D Scott Smith
- Department of Chemistry and Biochemistry, Wilfrid Laurier University, Waterloo, ON, Canada
| | - Adalberto L Val
- Laboratory of Ecophysiology and Molecular Evolution, Brazilian National Institute for Research of the Amazon, Manaus, AM, Brazil
| | - Chris M Wood
- Laboratory of Ecophysiology and Molecular Evolution, Brazilian National Institute for Research of the Amazon, Manaus, AM, Brazil.,Department of Zoology, University of British Columbia, Vancouver, BC, Canada
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Wood CM, Pelster B, Giacomin M, Sadauskas-Henrique H, Almeida-Val VMF, Val AL. The transition from water-breathing to air-breathing is associated with a shift in ion uptake from gills to gut: a study of two closely related erythrinid teleosts, Hoplerythrinus unitaeniatus and Hoplias malabaricus. J Comp Physiol B 2016; 186:431-45. [PMID: 26857274 DOI: 10.1007/s00360-016-0965-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [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: 10/15/2015] [Revised: 01/20/2016] [Accepted: 01/25/2016] [Indexed: 11/26/2022]
Abstract
The evolutionary transition from water-breathing to air-breathing involved not only a change in function of the organs of respiratory gas exchange and N-waste excretion, but also in the organs of ion uptake from the environment. A combination of in vivo and in vitro techniques was used to look at the relative importance of the gills versus the gut in Na(+), Cl(-), and K(+) balance in two closely related erythrinid species: a facultative air-breather, the jeju (Hoplerythrinus unitaeniatus) and an obligate water-breather, the traira (Hoplias malabaricus). The jeju has a well-vascularized physostomous swimbladder, while that in the traira is poorly vascularized, but the gills are much larger. Both species are native to the Amazon and are common in the ion-poor, acidic blackwaters of the Rio Negro. Under fasting conditions, the traira was able to maintain positive net Na(+) and Cl(-) balance in this water, and only slightly negative net K(+) balance. However, the jeju was in negative net balance for all three ions and had lower plasma Na(+) and Cl(-) concentrations, despite exhibiting higher branchial Na(+), K(+)ATPase and v-type H(+)ATPase activities. In the intestine, activities of these same enzymes were also higher in the jeju, and in vitro measurements of net area-specific rates of Na(+), Cl(-), and K(+) absorption, as well as the overall intestinal absorption capacities for these three ions, were far greater than in the traira. When acutely exposed to disturbances in water O2 levels (severe hypoxia ~15% or hyperoxia ~420% saturation), gill ionoregulation was greatly perturbed in the traira but less affected in the jeju, which could "escape" the stressor by voluntarily air-breathing. We suggest that a shift of ionoregulatory capacity from the gills to the gut may have occurred in the evolutionary transition to air-breathing in jeju, and in consequence branchial ionoregulation, while less powerful, is also less impacted by variations in water O2 levels.
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Affiliation(s)
- Chris M Wood
- Department of Zoology, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.
- Department of Biology, McMaster University, Hamilton, ON, Canada.
- Rosenstiel School of Marine and Atmospheric Science, University of Miami, Coral Gables, FL, USA.
- Laboratory of Ecophysiology and Molecular Evolution, Instituto Nacional de Pesquisas da Amazônia (INPA), Manaus, Amazonas, Brazil.
| | - Bernd Pelster
- Laboratory of Ecophysiology and Molecular Evolution, Instituto Nacional de Pesquisas da Amazônia (INPA), Manaus, Amazonas, Brazil
- Institute of Zoology, University of Innsbruck, Innsbruck, Austria
- Center for Molecular Biosciences, University of Innsbruck, Innsbruck, Austria
| | - Marina Giacomin
- Department of Zoology, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
- Laboratory of Ecophysiology and Molecular Evolution, Instituto Nacional de Pesquisas da Amazônia (INPA), Manaus, Amazonas, Brazil
| | - Helen Sadauskas-Henrique
- Laboratory of Ecophysiology and Molecular Evolution, Instituto Nacional de Pesquisas da Amazônia (INPA), Manaus, Amazonas, Brazil
| | - Vera Maria F Almeida-Val
- Laboratory of Ecophysiology and Molecular Evolution, Instituto Nacional de Pesquisas da Amazônia (INPA), Manaus, Amazonas, Brazil
| | - Adalberto Luis Val
- Laboratory of Ecophysiology and Molecular Evolution, Instituto Nacional de Pesquisas da Amazônia (INPA), Manaus, Amazonas, Brazil
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