Molecular and biochemical characterization of the bicarbonate-sensing soluble adenylyl cyclase from a bony fish, the rainbow trout .

Soluble adenylyl cyclase (sAC) is a -stimulated enzyme that produces the ubiquitous signalling molecule cAMP, and deemed an evolutionarily conserved acid-base sensor. However, its presence is not yet confirmed in bony fishes, the most abundant and diverse of vertebrates. Here, we identified sAC genes in various cartilaginous, ray-finned and lobe-finned fish species.

Physiological and morphological investigation of Arctic grayling () gill filaments with high salinity exposure and recovery.

Freshwater environments are at risk of increasing salinity due to multiple anthropogenic forces including current oil and gas extraction practices that result in large volumes of hypersaline water. Unintentional releases of hypersaline water into freshwater environments act as an osmoregulatory stressor to many aquatic organisms including native salmonids like the Arctic grayling (). Compared to more euryhaline salmonids, Arctic grayling have a reduced salinity tolerance and develop an elevated interlamellar cell mass (ILCM) in response to salinity exposure (17 ppt).

Reduced salinity tolerance in the Arctic grayling (Thymallus arcticus) is associated with rapid development of a gill interlamellar cell mass: implications of high-saline spills on native freshwater salmonids.

Arctic grayling (Thymallus arcticus) are salmonids that have a strict freshwater existence in post-glacial North America. Oil and gas development is associated with production of high volumes of hypersaline water. With planned industrial expansion into northern areas of Canada and the USA that directly overlap grayling habitat, the threat of accidental saline water release poses a significant risk.

Characterization of developmental Na(+) uptake in rainbow trout larvae supports a significant role for Nhe3b.

Developing freshwater fish must compensate for the loss of ions, including sodium (Na(+)), to the environment. In this study, we used a radiotracer flux approach and pharmacological inhibitors to investigate the role of sodium/hydrogen exchange proteins (Nhe) in Na(+) uptake in rainbow trout (Oncorhynchus mykiss) reared from fertilization in soft water (0.1mM Na(+)).

Ammonia excretion in the Atlantic hagfish (Myxine glutinosa) and responses of an Rhc glycoprotein.

Hagfishes, the most ancient of the extant craniates, demonstrate a high tolerance for a number of unfavorable environmental conditions, including elevated ammonia. Proposed mechanisms of ammonia excretion in aquatic organisms include vesicular NH(4)(+) transport and release by exocytosis in marine crabs, and passive NH(3) diffusion, active NH(4)(+) transport, and paracellular leakage of NH3 or NH(4)(+) across the gills of fishes. Recently, an emerging paradigm suggests that Rhesus glycoproteins play a vital role in ammonia transport in both aquatic invertebrates and vertebrates.

Acid-sensing ion channels are involved in epithelial Na+ uptake in the rainbow trout Oncorhynchus mykiss.

A role for acid-sensing ion channels (ASICs) to serve as epithelial channels for Na(+) uptake by the gill of freshwater rainbow trout was investigated. We found that the ASIC inhibitors 4',6-diamidino-2-phenylindole and diminazene decreased Na(+) uptake in adult rainbow trout in a dose-dependent manner, with IC50 values of 0.12 and 0.