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Vol. 48 No. 6, 2009
Transient Response of Brain Heat Shock Proteins 70 and 90 to
Acute Osmotic Stress in Tilapia (Oreochromis
mossambicus)
Meng-Wen
Yang1, Wei-Tung Huang2, May-Jywan Tsai3, Ing-Fong Jiang1, and
Ching-Feng Weng1,*
1Institute
of Biotechnology, National Dong Hwa University, Hualien 974, Taiwan
2Department of Molecular Biotechnology, Da-Yeh
University, Changhua 515, Taiwan
3Neural Regeneration Laboratory, Neurological
Institute, Taipei Veterans General Hospital, Taipei 112, Taiwan
Meng-Wen Yang,
Wei-Tung Huang, May-Jywan Tsai, Ing-Fong Jiang, and Ching-Feng Weng
(2009) Previous
studies demonstrated that gills play a major role in osmoregulation
during salinity changes. However, the regulatory mechanism in the
tilapia brain under osmolarity challenge remains unexplored.
Tilapia Oreochromis mossambicus
were transferred directly from fresh water (FW) to 25 ppt seawater (SW)
for 1, 2, 4, 8, and 24 h; or to 35 ppt SW for 1, 2, and 4 h, to
determine whether heat shock protein (HSP)70 and HSP90 in the brain
respond to acute hyperosmotic stress. After transfer to 25 ppt
SW, HSP70 and HSP90 messenger (m) RNA remained at higher levels
compared to the FW group. HSP70 and HSP90 protein levels in the
anterior and middle brain regions at 1 h after SW transfer were higher
than those of the FW group, and they had increased in the whole brain
at 1 h and were sustained to 4 h following transfer. After
transfer to 35 ppt SW, HSP70 mRNA had decreased at 1 h and increased at
4 h compared to values in FW; however, a lower HSP90 mRNA level was
observed at 4 h. For the whole brain, protein levels of HSP70 and
HSP90 after transfer to 35 ppt SW increased compared to those in FW
except at 2 h after transfer. The results suggest that HSP70 and
HSP90 may be involved in regulating the tilapia brain when faced with
acute osmotic stress and may subsequently facilitate adaptation to a SW
environment.
Key words: HSP70,
HSP90, Hyperosmotic, Brain, Tilapia, Oreochromis
mossambicus.
*Correspondence: Tel: 886-3-8633637. Fax:
886-3-8630255. E-mail:cfweng@mail.ndhu.edu.tw
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