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How does the Euryhaline freshwater toadfish, Allenbatrachus grunniens acclimatise to seawater?
Author
Koh, Catherine Chiaw Ling
Supervisor
Chew, Shit Fun
Abstract
Despite the family being mostly marine, the grunting toadfish, Allenbatrachus grunniens, is known to thrive in extremely dilute environment. What determines this tolerance is not well understood but it is probably related to physiological adjustment made to the gill in particular the regulation of Na+/K+-ATPase (NKA) and Na+/K+/Clcotransporter.
This study was undertaken to elucidate the mechanism involved in A. grunniens to cope with the change in salinity after direct transfer from freshwater to seawater (30‰), and also after 8 days exposure to seawater. The role of NKA in osmoregulation in A. grunniens was also examined by measuring its activities and protein expression in the gills after the toadfish was exposed to seawater for a longer period of 8 days.
A. grunniens was able to survive direct transfer from freshwater to seawater without going through a progressive increase in salinity. It acclimatized quickly to seawater and exhibited great tolerance to a change in salinity as compared to the climbing perch, four-eyed sleeper, or marble goby. The free amino acids contents in the muscle, liver and plasma increased significantly after short-term (1 d) exposure to seawater. Therefore, A. grunniens resorted to accumulation of free amino acids for cell volume regulation. Longer period (8 d) of exposure to seawater also resulted significant changes in the activity and protein abundances of the ion transporters involved in osmoregulation.
This study was undertaken to elucidate the mechanism involved in A. grunniens to cope with the change in salinity after direct transfer from freshwater to seawater (30‰), and also after 8 days exposure to seawater. The role of NKA in osmoregulation in A. grunniens was also examined by measuring its activities and protein expression in the gills after the toadfish was exposed to seawater for a longer period of 8 days.
A. grunniens was able to survive direct transfer from freshwater to seawater without going through a progressive increase in salinity. It acclimatized quickly to seawater and exhibited great tolerance to a change in salinity as compared to the climbing perch, four-eyed sleeper, or marble goby. The free amino acids contents in the muscle, liver and plasma increased significantly after short-term (1 d) exposure to seawater. Therefore, A. grunniens resorted to accumulation of free amino acids for cell volume regulation. Longer period (8 d) of exposure to seawater also resulted significant changes in the activity and protein abundances of the ion transporters involved in osmoregulation.
Date Issued
2010
Call Number
QL638.B3 Koh
Date Submitted
2010