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Urea-based osmoregulation in the developing embryo of oviparous cartilaginous fish (Callorhinchus milii): contribution of the extraembryonic yolk sac during the early developmental period
Citation
Takagi, W and Kajimura, M and Tanaka, H and Hasegawa, K and Bell, JD and Toop, T and Donald, JA and Hyodo, S, Urea-based osmoregulation in the developing embryo of oviparous cartilaginous fish (Callorhinchus milii): contribution of the extraembryonic yolk sac during the early developmental period, Journal of Experimental Biology, 217, (10) pp. 1353-1362. ISSN 0022-0949 (2014) [Refereed Article]
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Copyright Statement
Copyright 2014 The Company of Biologists Ltd-distributed under Creative Commons Attribution 3.0 Unported license (CC BY 3.0)
Official URL: http://dx.doi.org/10.1242/jeb.094649
Abstract
Marine cartilaginous fish retain a high concentration of urea to
maintain the plasma slightly hyperosmotic to the surrounding
seawater. In adult fish, urea is produced by hepatic and extrahepatic
ornithine urea cycles (OUCs). However, little is known about the urea
retention mechanism in developing cartilaginous fish embryos. In
order to address the question as to the mechanism of urea-based
osmoregulation in developing embryos, the present study examined
the gene expression profiles of OUC enzymes in oviparous
holocephalan elephant fish (Callorhinchus milii) embryos. We found
that the yolk sac membrane (YSM) makes an important contribution
to the ureosmotic strategy of the early embryonic period. The
expression of OUC enzyme genes was detectable in the embryonic
body from at least stage 28, and increased markedly during
development to hatching, which is most probably due to growth of the
liver. During the early developmental period, however, the expression
of OUC enzyme genes was not prominent in the embryonic body.
Meanwhile, we found that the mRNA expression of OUC enzymes
was detected in the extra-embryonic YSM; the mRNA expression of
cmcpsIII in the YSM was much higher than that in the embryonic
body during stages 28–31. Significant levels of enzyme activity and
the existence of mitochondrial-type cmgs1 transcripts in the YSM
supported the mRNA findings. We also found that the cmcpsIII
transcript is localized in the vascularized inner layer of the YSM.
Taken together, our findings demonstrate for the first time that the
YSM is involved in urea-based osmoregulation during the early to mid
phase of development in oviparous cartilaginous fish.
Item Details
| Item Type: | Refereed Article |
|---|---|
| Keywords: | yolk sac membrane, ornithine urea cycle enzymes, osmoregulation, urea synthesis, urea synthesis, organogenesis, oviparous, cartilaginous fish |
| Research Division: | Agricultural and Veterinary Sciences |
| Research Group: | Fisheries Sciences |
| Research Field: | Fish Physiology and Genetics |
| Objective Division: | Expanding Knowledge |
| Objective Group: | Expanding Knowledge |
| Objective Field: | Expanding Knowledge in the Biological Sciences |
| Author: | Bell, JD (Dr Justin Bell) |
| ID Code: | 91645 |
| Year Published: | 2014 |
| Web of Science® Times Cited: | 6 |
| Deposited By: | Sustainable Marine Research Collaboration |
| Deposited On: | 2014-05-23 |
| Last Modified: | 2017-11-04 |
| Downloads: | 214 View Download Statistics |
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