... in the gills. To further characterize the role of Pt Rh in ammonia metabolism and excretion, double-stranded RNA-mediated RNA interference of Pt Rh was employed. Knockdown of Pt Rh upregulated mRNA expression of ammonia excretion-related genes encoding aquaporin (AQP), K + channels and vesicle-associated...

...Dirk Weihrauch; Garett J. P. Allen ABSTRACT Invertebrates employ a variety of ammonia excretion strategies to facilitate their survival in diverse aquatic environments, including freshwater, seawater and the water film surrounding soil particles. Various environmental properties set innate...

... active Na + uptake are quite well understood in freshwater teleosts; however, the mechanisms employed by invertebrates are not. Pharmacological and molecular approaches were used to investigate Na + uptake mechanisms and their link to ammonia excretion in the ribbon leech Nephelopsis obscura...

..., across biological membranes. Zebrafish embryos were microinjected with a translation-blocking morpholino oligonucleotide targeted to AQP1a1. Knockdown of AQP1a1 significantly reduced rates of CO 2 and ammonia excretion, as well as water fluxes, in larvae at 4 days post fertilization (dpf). Because AQP1a1...

... metabolic rate (RMR) in FT phenotypes when fasting, and (2) tolerance reflects differences in substrate utilisation; FT phenotypes use relatively less proteins as metabolic fuels during fasting, measured as their ammonia quotient (AQ), the simultaneous ratio of ammonia excretion to RMR...

...C. Y. C. Hung; K. N. T. Tsui; J. M. Wilson; C. M. Nawata; C. M. Wood; P. A. Wright SUMMARY The mechanism(s) of ammonia excretion in the presence of elevated external ammonia are not well understood in fish. Recent studies in other organisms have revealed a new class of ammonia transporters, Rhesus...

...-mail: [email protected] 25 4 2006 © The Company of Biologists Limited 2006 2006 nitrogen excretion ammonia excretion oxygen consumption serotonin 5-HT ketanserin cortisol RU-486 killifish Rivulus marmoratus The rate of nitrogenous waste excretion in teleosts is largely...

...: a 24 h periodicity, a free-running rhythm in continuous conditions, and entrainment to new photoperiods. In fasted D. rerio , there was no significant circadian rhythm in urea and ammonia excretion ( F 2,9 =2.33, P =0.15, F 2,9 =1.28, P =0.33; Fig. 5A,B ). Approximately 83%of total nitrogen...

... site of NH 3 volatilization. * Author for correspondence (e-mail: [email protected] ) 7 3 2006 © The Company of Biologists Limited 2006 2006 NH 3 volatilization nitrogen excretion ammonia excretion water pH fish skin boundary layer amphibious fish Rivulus marmoratus...

...Dirk Weihrauch; Steve Morris; David W. Towle SUMMARY The excretory transport of toxic ammonia across epithelia is not fully understood. This review presents data combined with models of ammonia excretion derived from studies on decapod crabs, with a view to providing new impetus to investigation...

... for correspondence (e-mail: [email protected] ) 10 6 2004 © The Company of Biologists Limited 2004 2004 amino acids ammonia ammonia excretion feeding glutamine mudskipper nitrogen metabolism ornithine-urea cycle Periophthalmodon schlosseri urea When confronted with aerial...

... 11 2003 © The Company of Biologists Limited 2004 2004 aestivation Protopterus dolloi lungfish nitrogen metabolism ammonia excretion urea excretion mucus cocoon Lungfishes (or dipnoans, as they are `dual breathers') are an archaic group of fishes, characterized...

... Limited 2003 2003 ammonia ammonia detoxification ammonia excretion amino acid carbamoyl phosphate synthetase elasmobranch Himantura signifer nitrogen metabolism ornithine-urea cycle osmoregulation stingray urea urea excretion The synthesis of excretory urea in certain land...

... the effects of MSOX on ammonia excretion in vivo or in isolated head/gill preparations( Pärt et al., 1999 ). Clearly the gill GSase gene nucleotide and amino acid sequences are rather different from most other fish GSase genes examined to date (see Murray et al., 2003 ; Fig. 4 ). It is not clear...

... by DPC (10 -4 mol l -1 ) and thiocyanate (10 -4 mol l -1 ). Ammonia excretion was unresponsive to large changes in water Na + concentration, but was elevated by 70% during acute exposure to pH 4.0 and transiently inhibited by approximately 50% by amiloride and its analogues. The strategy of adaptation...

...Dirk Weihrauch; Andreas Ziegler; Dietrich Siebers; David W. Towle SUMMARY Although aquatic animals are generally believed to export nitrogenous waste by diffusion of NH 3 or NH 4 + across external epithelia, evidence for active ammonia excretion has been found in a number of species...

..., oxygen consumption and ammonia excretion rates increased approximately twofold following exhaustive exercise. Post-exercise oxygen consumption rates decreased to control levels within 30 min in both sturgeon species, but post-exercise ammonia excretion rates remained high in Atlantic sturgeon throughout...

...Annika Salama; Ian J. Morgan; Chris M. Wood ABSTRACT The nature of the linkage between between branchial ammonia excretion ( J Amm ) and unidirectional Na + influx was studied in the freshwater rainbow trout ( Oncorhynchus mykiss ). Arterial plasma total [ammonia], P NH and J Amm were all elevated...

...-bremerhaven.de † Present address: Institut für Tierphysiologie, Freie Universität Berlin, Grunewaldstrasse 34, D-12165, Berlin, Germany 9 10 1997 9 12 1997 © The Company of Biologists Limited 1988 acid–base regulation ammonia excretion buffer value CO2 partial pressure...

...E. Rahaman-Noronha; M. J. O’Donnell; C. M. Pilley; P. A. Wright ABSTRACT This study examined ammonia excretion by embryos of the rainbow trout ( Oncorhynchus mykiss ). The distribution of ammonia in relation to the H + distribution and electrical potential was determined. The influence of the pH...