Mechanisms of transepithelial ammonia excretion and luminal alkalinization in the gut of an intestinal air-breathing fish, <i>Misgurnus anguilliacaudatus</i>

Wilson, Jonathan M.; Moreira‐Silva, Joana; Delgado, Inês; Ebanks, Sue C.; Vijayan, Mathilakath M.; Coimbra, Joaquim Luís; Grosell, Martin

doi:10.1242/jeb.074401

Cited by 14 publications

(7 citation statements)

References 60 publications

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“…Ammonium ions (substituting for H + ) then pass into the epithelial boundary layer via an apical Na + /H + exchanger. Here the alkaline nature of the boundary layer facilitates the formation of gaseous ammonia (NH 3 ) which then volatilises (Wilson et al, 2013). The ability of galaxiid fish to volatilise ammonia from the cutaneous surface requires further investigation.…”

Section: Aquatic Normoxia (6 H)mentioning

confidence: 99%

Physiological and biochemical strategies for withstanding emersion in two galaxiid fishes

Urbina

Walsh

Hill

et al. 2014

Comparative Biochemistry and Physiology Part A: Molecular &

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Section: Aquatic Normoxia (6 H)mentioning

confidence: 99%

Physiological and biochemical strategies for withstanding emersion in two galaxiid fishes

Urbina

Walsh

Hill

et al. 2014

Comparative Biochemistry and Physiology Part A: Molecular &

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“…Ionocytes secrete and absorb ions in SW and FW environments, respectively (Hiroi & McCormick ). Although several ionocyte models have been described in different species and environments (Wilson, Laurent, Tufts, Benos, Donowitz, Vogl & Randall ; Wilson, Randall, Donowitz, Vogl & Ip ; Hwang, Lee & Lin ; Wilson, Moreira‐Silva, Delgado, Ebanks, Vijayan, Coimbra & Grosell ), the Na + /K + ‐ATPase (NKA) is the main driving force for ion uptake/secretion in these cells (Hirose et al . ; Hwang et al .…”

Section: Main Osmoregulatory Organs In Flatfish and Teleost In Generalmentioning

confidence: 99%

Environmental salinity and osmoregulatory processes in cultured flatfish

et al. 2014

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The aim of this study was to carry out a comparative analysis of the osmoregulatory properties and associated energy metabolism of euryhaline flatfish species that are cultured in the world. Culture of flatfish (pleuronectiformes) requires stage-and species-dependent osmotic conditions for rearing. Additionally, geographic origin of broodstock animals is another factor to be taken into account for the culture of pleuronectiformes. Larval and juvenile stages of many flatfish species are cultured in large nurseries situated in estuaries and shallow marine habitats, where the environmental salinity is close to the iso-osmotic point of their internal milieu. This fact implicates an advantage in terms of energy savings for osmoregulatory purposes. Thus, this 'saved' energy can be derived to other physiological processes, such as somatic growth. However, this scientific presumption does not always results in an optimal growth for many flatfish species. Indeed, iso-osmotic culture conditions can evoke a higher allostatic load than that in the usual hyper-osmotic environment where flatfish species live wildly. Optimization of flatfish culture thus requires adjustments of the osmotic culture conditions to the specific osmoregulatory and metabolic demands that eventually determine the allostatic load and consequently condition growth rates. In this sense, the geographical location of aquaculture farms and the osmoregulatory-based selection of the species to be cultivated in a particular area become critical factors to be considered for optimal flatfish culture.

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“…Various studies have shown that ammonia transport occurs often via tissues also responsible for gas exchange and/or osmoregulation such as skin (14,51,63), intestine (49,68,72), nephridial systems (29,32), gills (66,75), kidneys (59), and anal papillae (18,64). Early work on ammonia excretion suggested that transport of NH 3 was purely passive because of its assumed permeability in lipid bilayers (28) and the lack of identification of an NH 3 -transporting protein.…”

mentioning

confidence: 99%

Mechanism of ammonia excretion in the freshwater leechNephelopsis obscura: characterization of a primitive Rh protein and effects of high environmental ammonia

Quijada-Rodriguez

Treberg

Weihrauch

2015

American Journal of Physiology-Regulatory, Integrative and Comp

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Remarkably little is known about nitrogenous excretion in freshwater invertebrates. In the current study, the nitrogen excretion mechanism in the carnivorous ribbon leech, Nephelopsis obscura, was investigated. Excretion experiments showed that the ribbon leech is ammonotelic, excreting 166.0 ± 8.6 nmol·grams fresh weight (gFW)−1·h−1 ammonia and 14.7 ± 1.9 nmol·gFW−1·h−1 urea. Exposure to high and low pH hampered and enhanced, respectively, ammonia excretion rates, indicating an acid-linked ammonia trapping mechanism across the skin epithelia. Accordingly, compared with body tissues, the skin exhibited elevated mRNA expression levels of a newly identified Rhesus protein and at least in tendency the Na+/K+-ATPase. Pharmacological experiments and enzyme assays suggested an ammonia excretion mechanism that involves the V-ATPase, Na+/K+-ATPase, and carbonic anhydrase, but not necessarily a functional microtubule system. Most importantly, functional expression studies of the identified Rh protein cloned from leech skin tissue revealed an ammonia transport capability of this protein when expressed in yeast. The leech Rh-ammonia transporter (NoRhp) is a member of the primitive Rh protein family, which is a sister group to the common ancestor of vertebrate ammonia-transporting Rh proteins. Exposure to high environmental ammonia (HEA) caused a new adjustment of body ammonia, accompanied with a decrease in NoRhp and Na+/K+-ATPase mRNA levels, but unaltered ammonia excretion rates. To our knowledge, this is only the second comprehensive study regarding the ammonia excretion mechanisms in a freshwater invertebrate, but our results show that basic processes of ammonia excretion appear to also be comparable to those found in freshwater fish, suggesting an early evolution of ionoregulatory mechanisms in freshwater organisms.

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Mechanisms of transepithelial ammonia excretion and luminal alkalinization in the gut of an intestinal air-breathing fish, Misgurnus anguilliacaudatus

Cited by 14 publications

References 60 publications

Physiological and biochemical strategies for withstanding emersion in two galaxiid fishes

Physiological and biochemical strategies for withstanding emersion in two galaxiid fishes

Environmental salinity and osmoregulatory processes in cultured flatfish

Mechanism of ammonia excretion in the freshwater leechNephelopsis obscura: characterization of a primitive Rh protein and effects of high environmental ammonia

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