spacer gif spacer gif spacer gif spacer gif spacer gif
QUICK SEARCH:   [advanced]


spacer gif
     Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents    

First published online June 15, 2006
Journal of Experimental Biology 209, 2495-2508 (2006)
Published by The Company of Biologists 2006
doi: 10.1242/jeb.02294
This Article
Right arrow Summary Freely available
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Speers-Roesch, B.
Right arrow Articles by Ballantyne, J. S.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Speers-Roesch, B.
Right arrow Articles by Ballantyne, J. S.

Metabolic organization of freshwater, euryhaline, and marine elasmobranchs: implications for the evolution of energy metabolism in sharks and rays

B. Speers-Roesch1, Y. K. Ip2 and J. S. Ballantyne1,*

1 Department of Integrative Biology, University of Guelph, Guelph, Ontario, NIG 2W1, Canada
2 Department of Biological Science, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore


Figure 1
View larger version (18K):

[in a new window]
  		Fig. 1. Carnitine palmitoyl transferase (CPT) activities (mean ± s.e.m.) in liver and extrahepatic tissues of freshwater, euryhaline and marine elasmobranchs with varying levels of urea: Potamotrygon motoro (freshwater) (no urea), Himantura signifer in freshwater (low urea), H. signifer acclimated to half-strength seawater (1/2 Seawater) (increased urea), Taeniura lymma (marine) (high urea), and Chiloscyllium punctatum (marine) (high urea). See text or Fig. 4 for specific urea levels. Sample sizes and the results of statistical comparisons between tissues and species are given in Tables 1 and 2. The salinity (and thus urea level) for each species or acclimation group is indicated by the shading of the bars. Enzyme measurements were made at 25°C. ND, not detectable.

 

Figure 2
View larger version (18K):

[in a new window]
  		Fig. 2. 3-Hydroxyacyl CoA dehydrogenase (HOAD) activities (mean ± s.e.m.) in liver and extrahepatic tissues of freshwater, euryhaline and marine elasmobranchs with varying levels of urea: Potamotrygon motoro (freshwater) (no urea), Himantura signifer in freshwater (low urea), H. signifer acclimated to half-strength seawater (1/2 Seawater) (increased urea), Taeniura lymma (marine) (high urea) and Chiloscyllium punctatum (marine) (high urea). See text or Fig. 4 for specific urea levels. Sample sizes and the results of statistical comparisons between tissues and species are given in Tables 1 and 2. The salinity (and thus urea level) for each species or acclimation group is indicated by the shading of the bars. Enzyme measurements were made at 25°C. ND, not detectable.

 

Figure 3
View larger version (17K):

[in a new window]
  		Fig. 3. D-ß-hydroxybutyrate dehydrogenase (D-ß-HBDH) activities (mean ± s.e.m.) in liver and extrahepatic tissues of freshwater, euryhaline and marine elasmobranchs with varying levels of urea: Potamotrygon motoro (freshwater) (no urea), Himantura signifer in freshwater (low urea), H. signifer acclimated to half-strength seawater (1/2 Seawater) (increased urea), Taeniura lymma (marine) (high urea) and Chiloscyllium punctatum (marine) (high urea). See text or Fig. 4 for specific urea levels. Sample sizes and the results of statistical comparisons between tissues and species are given in Tables 1 and 2. The salinity (and thus urea level) for each species or acclimation group is indicated by the shading of the bars. Enzyme measurements were made at 25°C. ND, not detectable.

 

Figure 4
View larger version (17K):

[in a new window]
  		Fig. 4. Relationship between white muscle urea concentration and liver glutamate dehydrogenase (GDH) activity in elasmobranchs. Values are mean ± s.e.m. See text for full names of species. Error bars for GDH in Potamotrygon motoro and P. magdalenae are asymmetrical to avoid overlapping bars. 1GDH values are from the present study (see Table 1 for sample sizes) and urea values are from the same animals (N=5–8, taken from various studies) (Treberg et al., 2006Go). 2GDH value (Singer and Ballantyne, 1989Go); urea value was assumed to be the same as in P. motoro (Treberg et al., 2006Go). 3GDH value (Moon and Mommsen, 1987Go); urea value (Forster and Goldstein, 1976Go). 4GDH value (Battersby et al., 1996Go); urea value (Treberg and Driedzic, 2002Go). GDH activities for spiny dogfish and little skate were adjusted to 25°C using Q10=2. The regression is significant (r=0.93, P<0.001, linear regression ANOVA).

 

Figure 5
View larger version (13K):

[in a new window]
  		Fig. 5. Relationships between activities of carnitine palmitoyl tranferase (CPT) and D-ß-hydroxybutyrate dehydrogenase (D-ß-HBDH) in kidney (A), heart (B) and liver (C) of Potamotrygon motoro, Himantura signifer in freshwater (FW), H. signifer in half-strength (15{per thousand}) seawater (1/2 SW), Taeniura lymma, and Chiloscyllium punctatum. Each point refers to an individual animal. The regressions are significant for A (P<0.001, linear regression ANOVA) and B (P<0.01, linear regression ANOVA).

 




© The Company of Biologists Ltd 2006