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Vol. 48 No. 4, 2009
Constant
Muscle Water Content and Renal HSP90 Expression Reflect Osmotic
Homeostasis in Euryhaline Teleosts Acclimated to Different
Environmental Salinities
Cheng-Hao Tang1, Ching-San Tzeng1, Lie-Yueh Hwang2, and Tsung-Han Lee1,*
1Department of Life Sciences, National Chung-Hsing University, 250 Kuo-Kuang Rd., Taichung 402, Taiwan
2Taishi
Station, Mariculture Research Center, Fisheries Research Institute,
Council of Agriculture Taishi, Yunlin County 636, Taiwan
Cheng-Hao Tang, Ching-San Tzeng, Lie-Yueh Hwang, and Tsung-Han Lee (2009)
Changes in environmental salinities trigger osmoregulatory mechanisms
of euryhaline teleosts in order to maintain the plasma osmolality and
water balance. The kidneys are the osmoregulatory organ inside
the body which perform ion re-absorption and water regulation.
Heat shock proteins (HSPs) are also known as stress proteins, with
HSP90 as one of the major classes of HSPs essential for living
eukaryotes because it is responsible for the repair and refolding of
damaged proteins. In the present study, euryhaline tilapia (Oreochromis mossambicus), spotted green pufferfish (Tetraodon nigroviridis), and milkfish (Chanos chanos),
with respective primary natural habitats of freshwater lakes,
estuaries, and the sea, were acclimated to fresh water (FW), brackish
water (BW; 15‰ salinity), and seawater (SW; 35‰ salinity). The
muscle water content (MWC) and relative protein amounts of HSP90 in the
kidneys of the 3 studied species acclimated to different salinity
environments were analyzed in this study. The MWC of these 3
euryhaline teleosts revealed no significant changes in FW, BW, and
SW. Furthermore, relative protein amounts of renal HSP90 were
similar among the 3 studied species acclimated to various
environments. The physiological (MWC) and stress (HSP90)
responses integrated in this study might be indicators of
osmoregulatory capacity, illustrating homeostasis of the internal
environments of euryhaline teleosts.
Key words: Euryhaline teleost, Heat shock protein, Osmoregulation.
*Correspondence: Tel: 886-4-22856141. Fax: 886-4-22851797. E-mail:thlee@dragon.nchu.edu.tw
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