Back to Search
Start Over
Urea-based osmoregulation in the developing embryo of oviparous cartilaginous fish (Callorhinchus milii): contribution of the extraembryonic yolk sac during the early developmental period
- Source :
- Journal of Experimental Biology.
- Publication Year :
- 2013
- Publisher :
- The Company of Biologists, 2013.
-
Abstract
- SummaryMarine 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 extraembryonic 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 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.
- Subjects :
- Fish Proteins
Embryo, Nonmammalian
Physiology
Embryonic Development
Aquatic Science
Biology
Real-Time Polymerase Chain Reaction
Andrology
chemistry.chemical_compound
Osmoregulation
Gene expression
medicine
Animals
Urea
Yolk sac
Molecular Biology
Ecology, Evolution, Behavior and Systematics
Yolk Sac
Embryogenesis
Fishes
Embryo
Ornithine
medicine.anatomical_structure
Biochemistry
chemistry
Insect Science
Animal Science and Zoology
Transcriptome
Oviparity
Subjects
Details
- ISSN :
- 14779145 and 00220949
- Database :
- OpenAIRE
- Journal :
- Journal of Experimental Biology
- Accession number :
- edsair.doi.dedup.....94b789f020db1c29795e340397c9aa02