Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.

Science 20 October 1967:
Vol. 158. no. 3799, pp. 375 - 377
DOI: 10.1126/science.158.3799.375
Prev | Table of Contents | Next

Articles

Potamotrygon spp.: Elasmobranchs with Low Urea Content

Thomas B. Thorson 1, C. Michael Cowan 1, and Donald E. Watson 1

1 Department of Zoology and Physiology, University of Nebraska, Lincoln

All previously reported species of Chondrichthyes, from both marine and fresh water, have contained urea at concentrations ranging from about 300 to 1300 milligrams of urea nitrogen per 100 milliliters of fluid. Body fluids from two species of Potamotrygon, permanent residents of the Amazon basin, contained only 2 to 3 milligrams of urea nitrogen per 100 milliliters. Although they have abandoned the retention of urea exhibited by other chondrichthyans, the extent to which they have lost the mechanisms of retaining and tolerating urea in a hypertonic medium has not been determined.


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Metabolic organization of freshwater, euryhaline, and marine elasmobranchs: implications for the evolution of energy metabolism in sharks and rays.
B. Speers-Roesch, Y. K. Ip, and J. S. Ballantyne (2006)
J. Exp. Biol. 209, 2495-2508
   Abstract »    Full Text »    PDF »
The accumulation of methylamine counteracting solutes in elasmobranchs with differing levels of urea: a comparison of marine and freshwater species.
J. R. Treberg, B. Speers-Roesch, P. M. Piermarini, Y. K. Ip, J. S. Ballantyne, and W. R. Driedzic (2006)
J. Exp. Biol. 209, 860-870
   Abstract »    Full Text »    PDF »
Cloning and characterization of cDNAs encoding steroidogenic acute regulatory protein from freshwater stingrays (Potamotrygon spp.).
B S Nunez, P M Piermarini, A N Evans, and S L Applebaum (2005)
J. Mol. Endocrinol. 35, 557-569
   Abstract »    Full Text »    PDF »
The Multifunctional Fish Gill: Dominant Site of Gas Exchange, Osmoregulation, Acid-Base Regulation, and Excretion of Nitrogenous Waste.
D. H. Evans, P. M. Piermarini, and K. P. Choe (2005)
Physiol Rev 85, 97-177
   Abstract »    Full Text »    PDF »
A comparison of the effects of environmental ammonia exposure on the Asian freshwater stingray Himantura signifer and the Amazonian freshwater stingray Potamotrygon motoro.
Y. K. Ip, W. L. Tam, W. P. Wong, A. M. Loong, K. C. Hiong, J. S. Ballantyne, and S. F. Chew (2003)
J. Exp. Biol. 206, 3625-3633
   Abstract »    Full Text »    PDF »
The osmotic response of the Asian freshwater stingray (Himantura signifer) to increased salinity: a comparison with marine (Taeniura lymma) and Amazonian freshwater (Potamotrygon motoro) stingrays.
W. L. Tam, W. P. Wong, A. M. Loong, K. C. Hiong, S. F. Chew, J. S. Ballantyne, and Y. K. Ip (2003)
J. Exp. Biol. 206, 2931-2940
   Abstract »    Full Text »    PDF »
Mechanisms of ion transport in Potamotrygon, a stenohaline freshwater elasmobranch native to the ion-poor blackwaters of the Rio Negro.
C. M. Wood, A. Y. O. Matsuo, R. J. Gonzalez, R. W. Wilson, M. L. Patrick, and A. L. Val (2002)
J. Exp. Biol. 205, 3039-3054
   Abstract »    Full Text »    PDF »
Immunochemical analysis of the vacuolar proton-ATPase B-subunit in the gills of a euryhaline stingray (Dasyatis sabina): effects of salinity and relation to Na+/K+-ATPase.
P. M. Piermarini and D. H. Evans (2001)
J. Exp. Biol. 204, 3251-3259
   Abstract »    Full Text »    PDF »
Glutamine synthetase: assimilatory role in liver as related to urea retention in marine chondrichthyes.
J. Webb and G. Brown Jr (1980)
Science 208, 293-295
   Abstract »    PDF »


To Advertise     Find Products

Science. ISSN 0036-8075 (print), 1095-9203 (online)