An investigation of the loss of bound calcium from the gills of the brown trout, Salmo trutta, in acid media

McWilliams, P. G.

doi:10.1016/0300-9629(83)90720-x

Cited by 68 publications

(30 citation statements)

References 48 publications

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“…In vertebrates including fish, paracellular permeability is governed primarily by TJ proteins, which regulate the intercellular passage of water, ions and neutral solutes (Anderson and Van Itallie, 2009;Chasiotis et al, 2012;Engelund et al, 2012; Kwong and Perry, 2013b; Kwong et al, 2013b). In FW trout, acid exposure leaches surface-bound Ca 2+ , disrupts the morphology of TJs in the gills and thus increases Na + efflux (Freda et al, 1991;McWilliams, 1983). In agreement with this finding, removal of ambient Ca 2+ caused a more pronounced Na + loss in zebrafish exposed to acidic water .…”

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confidence: 72%

The physiology of fish at low pH: the zebrafish as a model system

Kwong

Kumai

Perry

2014

Journal of Experimental Biology

119

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Ionic regulation and acid-base balance are fundamental to the physiology of vertebrates including fish. Acidification of freshwater ecosystems is recognized as a global environmental problem, and the physiological responses to acid exposure in a few fish species are well characterized. However, the underlying mechanisms promoting ionic and acid-base balance for most fish species that have been investigated remain unclear. Zebrafish (Danio rerio) has emerged as a powerful model system to elucidate the molecular basis of ionic and acid-base regulation. The utility of zebrafish is related to the ease with which it can be genetically manipulated, its suitability for state-of-the-art molecular and cellular approaches, and its tolerance to diverse environmental conditions. Recent studies have identified several key regulatory mechanisms enabling acclimation of zebrafish to acidic environments, including activation of the sodium/hydrogen exchanger (NHE) and H + -ATPase for acid secretion and Na + uptake, cortisol-mediated regulation of transcellular and paracellular Na + movements, and ionocyte proliferation controlled by specific cell-fate transcription factors. These integrated physiological responses ultimately contribute to ionic and acid-base homeostasis in zebrafish exposed to acidic water. In the present review, we provide an overview of the general effects of acid exposure on freshwater fish, the adaptive mechanisms promoting extreme acid tolerance in fishes native to acidic environments, and the mechanisms regulating ionic and acid-base balance during acid exposure in zebrafish. KEY WORDS: Acid exposure, Acid-base balance, Ionic regulation, Zebrafish IntroductionDeclining fish populations in acidified lakes and streams (see review by McDonald, 1983a) was a significant factor promoting intensive research over the past 40 years on the ecological and physiological consequences of aquatic acidification. In freshwater (FW) ecosystems, acidification is caused largely by atmospheric acidic deposition (i.e. acid rain). Acidification of FW is a global problem, which has been documented in several geographic regions including eastern Europe, the USA and China (Psenner, 1994;Schindler, 1988;Wright et al., 2005). In Canada, it is estimated that about 40% of lakes are in regions susceptible to acid deposition (Kelso et al., 1990). Most aquatic animals, including fish, live in a narrow range of pH near neutrality, and acute or chronic exposure to acidic water can adversely affect their physiological functions (McDonald, 1983a;Wood, 1989). Nevertheless, some species thrive in acidic environments, and thus can serve as useful models for investigating the mechanisms underlying adaptation to acid stress. REVIEWDepartment of Biology, University of Ottawa, 30 Marie Curie, Ottawa, ON, Canada, K1N 6N5.*Author for correspondence (wkwong@uottawa.ca)The mechanisms of ionic and acid-base regulation in fish have been summarized in previous reviews (Claiborne et al., 2002;Evans et al., 2005;Gilmour and Perry, 2009;Goss et al., 19...

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confidence: 72%

The physiology of fish at low pH: the zebrafish as a model system

Kwong

Kumai

Perry

2014

Journal of Experimental Biology

119

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“…The increased efflux may be, at least in the case of Na+, partially due to changes in the electrical potential across the gill (74), but it is more likely that the generalized NaCl loss is secondary to increased leakiness of the branchial epithelium produced by acid titration of the Ca2" on the gill membrane. This view is supported by the fact that low Ca2" solutions exacerbate the effect of low external pH (see above), and low pH solutions significantly increase the rate of efflux of bound Ca2" from gills isolated from brown trout, Salmo trutta (75) and increase the electrical conductance, as well as the Na+, Cl-, and mannitol effluxes, across the isolated opercular epithelium of S. fontinalis (76). The precise locus and mechanism(s) of inhibition of Na+ and Cl-uptake remain unknown.…”

Section: Aquatic Acidificationsupporting

confidence: 50%

The fish gill: site of action and model for toxic effects of environmental pollutants.

Evans¹

1987

Environ Health Perspect

329

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The gill epithelium is the site of gas exchange, ionic regulation, acid-base balance, and nitrogenous waste excretion by fishes. The last three processes are controlled by passive and active transport of various solutes across the epithelium. Various environmental pollutants (e.g., heavy metals, acid rain, and organic xenobiotics) have been found to affect the morphology of the gill epithelium. Associated with these morphological pathologies, one finds alterations in blood ionic levels, as well as gill Na,K-activated ATPase activity and ionic fluxes. Such physiological disturbances may underly the toxicities of these pollutants. In addition, the epithelial transport steps which are affected in the fish gill model resemble those described in the human gut and kidney, sites of action of a variety of environmental toxins. Images FIGURE 1. a FIGURE 1. b FIGURE 3.

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“…Acid-stressed fish tend to lose calcium, which has considerable physiological importance on the stability and permeability of biological membranes (Schoeffeniels 1967, McWilliams 1983. McDonald (1983) and Marshall (1985) suggested the initial large passive ion effluxes at low pH are due to H+ displacing Ca*+ from the gill paracellular diffusion channels.…”

Section: Discussionmentioning

confidence: 99%

The effects of aluminum and acid on the gill morphology in rainbow trout, Salmo gairdneii

1988

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SynopsisThe objective was to determine the effects of acid and aluminum in acidified hard and soft water on the histology and morphometry of rainbow trout gills, and to determine relevant toxicity indicators within the gill tissue. Acid and aluminum promoted measurable primary epithelial hyperplasia which proved to be a reliable biological indicator of acid and aluminum contamination and possibly of some predictive value. Low levels of aluminum and acid resulted in hypertrophied chloride cells, suggesting a role in adapting to the contaminants. High concentrations of aluminum (>lO~.~moll-') caused chloride cell necrosis and consequently a decline in cell numbers over time. Aluminum precipitates accumulating within the chloride cell cytoplasm probably lead to impaired function prior to cell degeneration. The morphological alterations resulted in a decrease in water space between secondary lamellae (up to 40% within 14 d) which may reduce the efficiency of gas exchange. Twice the aluminum was required in hard water to elicit a similar soft water tissue response. Pathological changes were more severe with aluminum at pH 5.2 than at pH 4.7; results of aluminum speciation suggest that both labile and non-labile fractions are responsible for the induction of gill lesions. Low levels of aluminum may protect fish from the effects of high hydrogen ion concentration.

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An investigation of the loss of bound calcium from the gills of the brown trout, Salmo trutta, in acid media

Cited by 68 publications

References 48 publications

The physiology of fish at low pH: the zebrafish as a model system

The physiology of fish at low pH: the zebrafish as a model system

The fish gill: site of action and model for toxic effects of environmental pollutants.

The effects of aluminum and acid on the gill morphology in rainbow trout, Salmo gairdneii

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