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Academic Background

  • BSc (Honours); PhD NUS

Professional Organisations

  • European Society for Comparative Physiology and Biochemistry, Member
  • Singapore Institute of Biology, Member


  • AAB102 Cell Structure and Function
  • AAB206 General Physiology
  • AAB301 Biochemistry
  • AAB302 Animal Physiology
  • ASK301/DSS100 Topics in Primary Science for Primary Teaching
  • MLS828 Environmental Health & Toxicology
  • MLS865 Comparative Environmental Physiology
  • QUB512 Biochemical & Physiological Basis of Life

Research Interests

On the mudflats of Singapore, dwell many interesting intertidal organisms like the mudskippers, sipunculids and the intertidal pulmonates. We are intrigued by the capabilities of these organisms in surviving in such harsh environment.  These intertidal organisms are exposed to low oxygen tension since they burrow into the mudflats.  They are also exposed to the fluctuating salinities and the high sulfide content in the mudflats.  Thus, our laboratory has been actively involved in elucidating the biochemical strategies employed by these organisms in adapting to the harsh environment in the mudflats.  Recently, we have been looking extensively on the nitrogen metabolism of some interesting fish during terrestrial excursion and high ammonia exposure. These include Misgurnus anguillicaudatus also known as the weatherloach, Oxyeleotris marmoratus commonly known as Soon Hock (a delicacy serve in our local restaurants), Channa asiatica (also called the snakehead which is well known as a tonic used to speed recovery after a surgery), Periophthalmodon schlosseri (a giant mudskipper found in Pasir Ris Mangrove), Monopterus albus (swamp eel), Protopterus spp (African lungfish) and Himantura signifer (freshwater stingray).  Our results indicated that different fishes used different strategies to prevent ammonia build-up in their tissues.


Ip, Y. K. & Chew, S. F. (2010). Nitrogen metabolism and excretion during aestivation. IN Navas, C. A. & Carvalho, J. E. (EDS.), Progress in Molecular and Subcellular Biology, Vol 49, Aestivation Molecular and Physiological Aspects (PP. 63-94). Berlin Heidelberg: Springer-Verlag.
Chew, S F, J M Wilson, Y K Ip and D J Randall (2006). Nitrogen excretion and defence against ammonia toxicity. IN A Val, V Almedia-Val and D J Randall (ED.), Fish Physiology, Vol. 21, The Physiology of Tropical Fishes (PP. 307 - 395). New York: Academic Press.
Ip, Y K, S F Chew and D J Randall (2001). Ammonia Toxicity, Tolerance and Excretion. IN P.M. Anderson and P.A. Wright (ED.), Fish Physiology, Vol 19, Nitrogen excretion (PP. 109-148). New York: Academic Press.


Chew, S. F., and Ip, Y. K. (2014). Excretory nitrogen metabolism and defense against ammonia toxicity in air-breathing fishes. Journal of Fish Biology, doi:10.1111/,(), jfb.12279.
Ip, Y. K., Loong, A. M., Kuah, J S, Sim, E W L, Chen, X. L., Wong, W. P., Lam, S. H., Delgado, I. L. S., Wilson, J. M. and Chew, S. F. (2012). Roles of three branchial Na+-K+-ATPase á-subunit isoforms in freshwater adaptation, seawater acclimation, and active ammonia excretion in Anabas testudineus.. American Journal of Physiology - Regulatory Integrative Comparative Physiology, 303,(), R112-R125..
Ip, Y K, A M Loong, Lee, S M L, Ong, J L Y, Wong, W P, and S F Chew (2012). The Chinese soft-shelled turtle, Pelodiscus sinensis, excretes urea mainly through the mouth instead of the kidney. Journal of Experimental Biology, 215,(), 3723-3733.
Ip, Y. K. & Chew, S. F. (2010). Ammonia Production, excretion, toxicity, and defense in fish: a review. Frontiers in Physiology, 1,(), doi: 10.3389/fphys.2010.00134.
Peh, W.Y.X., Chew, S.F., Ching, B.Y., Loong, A.M. & Ip, Y. K. (2010). Roles of intestinal glutamate dehydrogenase and glutamine synthetase in environmental ammonia detoxification in the euryhaline four-eyed sleeper, Bostrychus sinensis. Aquatic Toxicology, 98,(), 91-98.
Chew, S .F., Tng, Y. Y. M., Wee, N. L. J. Wilson, J. M. & Ip, Y. K. 154: 360-369. (2009). Nitrogen metabolism and branchial osmoregulatory acclimation in the juvenile marble goby, Oxyeleotris marmorata, exposed to seawater.. Comparative Biochemistry & Physiology Part A : Molecular & Integrative Physiology, 154,(3), 360-369.
Tng, Y. Y. M., Wee, N. L. J., Ip, Y. K., Chew, S. F. (2008). Postprandial nitrogen metabolism and excretion in juvenile marble goby, Oxyeleotris marmorata (Bleeker, 1852). Aquaculture, 284,(), 260-267.
Chew, S. F., Sim, M. Y., Phua, Z. C., Wong, W. P. & Ip, Y. K. (2007). Active Ammonia excretion in the giant mudskipper, Periophthalmodon schlosseri (Pallas), during emersion. J of Experimental Zoology, Part A-Ecological Genetics & Physiology, 307A,(), 357-369.
Chew, S. F., Poothodiyil,N. K., Wong. W. P., & Ip, Y. K. (2006). Exposure to brackish water, upon feeding, leads to enhanced conservation of nitrogen and increased urea synthesis and retention in the Asian freshwater stingray Himantura signifer.. Journal of Experimental Biology, 209,(), 484-492.
Chew, S F, J Gan and Y K Ip (2005). Nitrogen metabolism and excretion in the swamp eel, Monopterus albus, during 6 or 40 days of aestivation in mud. Physiological and Biochemical Zoology, 78,(NA), 620-629.
Chew S F, N K Y Chan, A M Loong, K C Hiong, W L Tam, and Y K Ip (2004). Nitrogen metabolism in the African lungfish (Protopterus dolloi) aestivating in a mucus cocoon on land. Journal of Experimental Biology, 207,(NA), 777-786.
Chew S F, T F Ong, L Ho, W L Tam, A M Loong, K C Hiong, W P Wong and Y K Ip (2003). Urea synthesis in the African Lungfish Protopterus dolloi- hepatic carbamoyl phosphate synthetase III and glutamine synthetase are up-regulated by 6 days of aerial exposure. Journal of Experimental Biology, 206,(NA), 3615-3624.
Chew, S F, M Y Wong, W L Tam and Y K Ip (2003). The snakehead Channa asiatica accumulates alanine during aerial exposure, but is incapable of sustaining locomotory activities on land through partial amino acid catabolism. Journal of Experimental Biology, 206,(5), 693-704.
Chew, S F, Y Jin and Y K Ip, (2001). The loach Misgurnus angullicaudatus reduces amino acid catabolism, and accumulate alanine and glutamine during aerial exposure. Physiological & Biochemical Zoology, 74,(2), 226-237.
Randall, D J, J M Wilson, K W Peng, T W K Kok, S S L Kuah, S F Chew, T J Lam, and Y K I (1999). The mudskipper, Periophthalmodon schlosseri, actively transports NH4+ against a concentration gradient. American Journal of Physiology, 272,(2), 1562-1567.
Lim, C B, W P Low, S F Chew and Y K Ip (1996). Survival of the intertidal pulmonate Onchidium tumidium during short and long term anoxic stress. Marine Biology, 125,(), 707-713.
biochemistry, physiology & biochemistry of fishes