Please use this identifier to cite or link to this item: https://doi.org/10.1242/jeb.025395
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dc.titleGlutamine accumulation and up-regulation of glutamine synthetase activity in the swamp eel, Monopterus albus (Zuiew), exposed to brackish water
dc.contributor.authorTok, C.Y.
dc.contributor.authorChew, S.F.
dc.contributor.authorPeh, W.Y.X.
dc.contributor.authorLoong, A.M.
dc.contributor.authorWong, W.P.
dc.contributor.authorIp, Y.K.
dc.date.accessioned2014-10-27T08:29:35Z
dc.date.available2014-10-27T08:29:35Z
dc.date.issued2009-05-01
dc.identifier.citationTok, C.Y., Chew, S.F., Peh, W.Y.X., Loong, A.M., Wong, W.P., Ip, Y.K. (2009-05-01). Glutamine accumulation and up-regulation of glutamine synthetase activity in the swamp eel, Monopterus albus (Zuiew), exposed to brackish water. Journal of Experimental Biology 212 (9) : 1248-1258. ScholarBank@NUS Repository. https://doi.org/10.1242/jeb.025395
dc.identifier.issn00220949
dc.identifier.urihttp://scholarbank.nus.edu.sg/handle/10635/100777
dc.description.abstractThe swamp eel, Monopterus albus, is an air-breathing teleost which typically lives in freshwater but can also be found in estuaries, where it has to deal with ambient salinity fluctuations. Unlike other teleosts, its gills are highly degenerate. Hence, it may have uncommon osmoregulatory adaptations, but no information is available on its osmoregulatory capacity and mechanisms at present. In this study M. albus was exposed to a 5day progressive increase in salinity from freshwater (1%o) to brackish water (25V) and subsequently kept in 25V water for a total of 4days. The results indicate that M. albus switched from hyperosmotic hyperionic regulation in freshwater to a combination of osmoconforming and hypoosmotic hypoionic regulation in 25V water. Exposure to 25V water resulted in relatively large increases in plasma osmolality, [Na+] and [Cl-]. Consequently, fish exposed to 25V water had to undergo cell volume regulation through accumulation of organic osmolytes and inorganic ions. Increases in tissue free amino acid content were apparently the result of increased protein degradation, decreased amino acid catabolism, and increased synthesis of certain non-essential amino acids. Here we report for the first time that glutamine is the major organic osmolyte in M. albus. Glutamine content increased to a phenomenal level of >12|imolg-1 and >30|imolg-1 in the muscle and liver, respectively, of fish exposed to 25V water. There were significant increases in glutamine synthetase (GS) activity in muscle and liver of these fish. In addition, exposure to 25V water for 4 days led to significant increases in GS protein abundance in both muscle and liver, indicating that increases in the expression of GS mRNA could have occurred.
dc.description.urihttp://libproxy1.nus.edu.sg/login?url=http://dx.doi.org/10.1242/jeb.025395
dc.sourceScopus
dc.subjectAmmonia
dc.subjectGlutamine
dc.subjectGlutamine synthetase
dc.subjectMonopterus albus
dc.subjectNitrogen metabolism
dc.subjectOsmoregulation
dc.subjectSwamp eel
dc.typeArticle
dc.contributor.departmentBIOLOGICAL SCIENCES
dc.description.doi10.1242/jeb.025395
dc.description.sourcetitleJournal of Experimental Biology
dc.description.volume212
dc.description.issue9
dc.description.page1248-1258
dc.description.codenJEBIA
dc.identifier.isiut000265271500011
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