Urea-based osmoregulation in the developing embryo of oviparous cartilaginous fish (Callorhinchus milii) : contribution of the extraembryonic yolk sac during the early developmental period Takagi,W, Kajimura,M, Tanaka,H, Hasegawa,K, Bell,JD, Toop,T, Donald,JA and Hyodo,S 2014, Urea-based osmoregulation in the developing embryo of oviparous cartilaginous fish (Callorhinchus milii) : contribution of the extraembryonic yolk sac during the early developmental period, The Journal of Experimental Biology, vol. 217, no. 8, pp. 1353-1362, doi: 10.1242/jeb.094649. Attached Files Name Description MIMEType Size Downloads Title Urea-based osmoregulation in the developing embryo of oviparous cartilaginous fish (Callorhinchus milii) : contribution of the extraembryonic yolk sac during the early developmental period Author(s) Takagi,W Kajimura,M Tanaka,H Hasegawa,K Bell,JD Toop,T Donald,JA orcid.org/0000-0001-5930-2642 Hyodo,S Journal name The Journal of Experimental Biology Volume number 217 Issue number 8 Start page 1353 End page 1362 Total pages 10 Publisher Company of Biologists Place of publication Cambridge, United Kingdom Publication date 2014-04-01 ISSN 1477-9145 Keyword(s) Organogenesis Ornithine urea cycle enzymes Osmoregulation Oviparous cartilaginous fish Urea synthesis Yolk sac membrane Science & Technology Life Sciences & Biomedicine Biology Life Sciences & Biomedicine - Other Topics CARBAMOYL-PHOSPHATE SYNTHETASE SCYLIORHINUS-CANICULA L SKATE RAJA-ERINACEA ELASMOBRANCH EMBRYOS GLUTAMINE-SYNTHETASE CARCHARHINUS-LEUCAS NITROGEN-EXCRETION NA+/K+-ATPASE CYCLE ENZYMES DOGFISH Animals Embryo, Nonmammalian Embryonic Development Fish Proteins Fishes Osmoregulation Real-Time Polymerase Chain Reaction Transcriptome Urea Yolk Sac Summary 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. Language eng DOI 10.1242/jeb.094649 Field of Research 060807 Animal Structure and Function Socio Economic Objective 970106 Expanding Knowledge in the Biological Sciences HERDC Research category C1 Refereed article in a scholarly journal ERA Research output type C Journal article Copyright notice ©2014, Company of Biologists Persistent URL http://hdl.handle.net/10536/DRO/DU:30071571 Document type: Journal Article Collections: Faculty of Science, Engineering and Built Environment School of Life and Environmental Sciences Related Links Link Description Connect to Elements publication management system Go to link with your DU access privileges   Connect to published version Go to link with your DU access privileges   Author URL Go to link with your DU access privileges     Unless expressly stated otherwise, the copyright for items in DRO is owned by the author, with all rights reserved. Versions Version Filter Type Thu, 19 Mar 2015, 09:08:48 EST Fri, 20 Mar 2015, 04:01:37 EST Fri, 20 Mar 2015, 05:10:12 EST Tue, 24 Mar 2015, 11:11:21 EST Tue, 24 Mar 2015, 11:22:55 EST Sat, 09 Nov 2019, 23:37:28 EST Tue, 19 Apr 2022, 12:36:47 EST Filtered Full Citation counts:   Cited 10 times in TR Web of Science Cited 9 times in Scopus Search Google Scholar Access Statistics: 640 Abstract Views, 4 File Downloads  -  Detailed Statistics Created: Thu, 19 Mar 2015, 09:08:48 EST