... gills, may be exceptionally important in ionoregulation and nitrogen (N) waste excretion, with support of kidney function by direct O 2 supply from the airspace. We tested these ideas by continuous urine collection and gill flux measurements in ∼700 g fish. ATPase activities were many-fold greater...

...Christian Kropf; Karl Fent; Stephan Fischer; Ayako Casanova; Helmut Segner ABSTRACT Fish gills are a structurally and functionally complex organ at the interface between the organism and the aquatic environment. Gill functions include the transfer of organic molecules, both natural ones...

... salinities, ventilation increased and heart rate fell in the classic manner, while Ṁ O 2 initially declined by ∼50%, with partial restoration by 3 h of hypoxia, and no O 2 debt repayment during recovery. Gill paracellular permeability (measured with [ 14 C] PEG-4000) was 1.4-fold higher in seawater...

... crabs ( Limulus polyphemus ), book gills bear physiologically distinct regions: dorsal and ventral half-lamellae, a central mitochondria-rich area (CMRA) and peripheral mitochondria-poor areas (PMPAs). In the present study, the CMRA and ventral half-lamella exhibited characteristics important...

... in this ancient group. We cloned Rh cDNAs ( Rhag, Rhbg and Rhp2 ) and evaluated gill ammonia handling in Squalus acanthias . Control ammonia excretion was <5% of urea-N excretion. Sharks exposed to high environmental ammonia (HEA; 1 mmol −1 NH 4 HCO 3 ) for 48 h exhibited active ammonia uptake against partial...

... . This euryhaline teleost lacks both a stomach and the capacity for Cl − uptake at the gills in freshwater. PEG-4000 appearance in the water was minimal up to 10–11 h post-feeding, indicating the virtual absence of Na + and Cl − loss in the faeces up until this time. Rapid uptake of dietary Na + and Cl − occurred...

... an NH 3 diffusion gradient across the gills against the high external pH. In standard ammoniotelic teleosts, branchial ammonia excretion is facilitated by Rh glycoproteins, and cortisol plays a role in upregulating these carriers, together with other components of a transport metabolon, so...

... environmental ammonia (HEA; 1 and 5 mmol l –1 NH 4 HCO 3 ) and evaluated the patterns of ammonia excretion and gill Rh mRNA and protein expression. Gill H + -ATPase , NHE1 , NHE2 , NHE3 , Na + /K + -ATPase ( NKA ), Na + /K + /2Cl – co-transporter ( NKCC1 ) mRNA, H + -ATPase activity, NKA protein and activity...

... internal and external stimuli. The putative location of the chemoreceptors was determined by bilateral denervation of branches of cranial nerves IX (glossopharyngeal) and X (vagus) to the gills. The data indicate that the chemoreceptors eliciting bradycardia, hypertension and gill ventilatory responses...

... and secretion across their gills. Many studies have examined the mechanisms responsible for long-term (days) salinity acclimation; however, much remains unknown about the mechanisms of acute (hours) salinity acclimation. In this study, we tested the hypotheses that phosphorylation of the Na + –K + –Cl...

...Marvin H. Braun; Shelby L. Steele; Steve F. Perry SUMMARY While adult zebrafish, Danio rerio , possess ammonia and urea transporters (Rh and UT proteins, respectively) in a number of tissues, they are most heavily concentrated within the gills. UT has a diffuse expression pattern within Na + -K...

...Dirk Weihrauch; Michael P. Wilkie; Patrick J. Walsh SUMMARY The diversity of mechanisms of ammonia and urea excretion by the gills and other epithelia of aquatic organisms, especially fish and crustaceans, has been studied for decades. Although the decades-old dogma of `aquatic species excrete...

...T. K. N. Tsui; C. Y. C. Hung; C. M. Nawata; J. M. Wilson; P. A. Wright; C. M. Wood SUMMARY The mechanisms of ammonia excretion at fish gills have been studied for decades but details remain unclear, with continuing debate on the relative importance of non-ionic NH 3 or ionic NH 4 + permeation...

.... For terrestrial eggs of red-eyed treefrogs, the embryonic period can extend ∼50% longer than development to hatching competence, and development is synchronous across perivitelline oxygen levels( P O 2 ) ranging from 0.5–16.5 kPa. Embryos maintain large external gills until hatching, then gills regress rapidly...

... rainbow trout tissues responded to high environmental ammonia. To determine whether or not Rh proteins may also be involved in CO 2 transport in rainbow trout,we examined the effects of a 12 h exposure to external hypercapnia (1%CO 2 in air) on Rh mRNA expression in the gill, skin and erythrocytes...

... – ] were unchanged after transfer, and plasma cortisol underwent a transient increase. Na + /K + -ATPase activity increased 1.5-fold in the gills and opercular epithelium at 7 days (significant in gills only), responses that were preceded by three- to fourfold increases in Na + /K + -ATPase α 1a mRNA...

... the localization and expression of occludin, a transmembrane TJ protein, in goldfish tissues. In goldfish gills,discontinuous occludin immunostaining was detected along the edges of secondary gill lamellae and within parts of the interlamellar region that line the lateral walls of the central venous sinus...

... transmembrane domains. RhBG , RhCG1 and RhCG2 are highly expressed in gill tissue, with RhBG also present in skin of K. marmoratus . Exposure to elevated environmental ammonia (2 mmol l –1 NH 4 HCO 3 ) for 5 days resulted in a modest (+37%) increase in whole-body ammonia levels, whereas gill RhCG2 and skin...

... for a successful terrestrial invasion. Crabs can actively uptake or excrete ions upon salinity change, and the gills play a major role among the osmoregulatory organs. Several enzymes are involved in the osmoregulatory process, including Na + ,K + -ATPase and V-type H + -ATPase (V-H + -ATPase). Na + ,K + -ATPase...

... and pH i , respectively) on isolated vessels from steelhead and rainbow trout ( Oncorhynchus mykiss , Skamania and Kamloops strains,respectively) and of pH o on perfused gills from rainbow trout. In otherwise unstimulated (resting) efferent branchial (EBA) and coeliaco-mesenteric arteries (CMA), anterior...