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Vol. 42 No. 1, 2003
Na+,K+,2Cl--cotransporter: A Novel Marker for Identifying Freshwater and Seawater-type Mitochondria-rich Cells in Gills of the Euryhaline Tilapia, Oreochromis mossambicus
Yu-Ching Wu1, Li-Yih Lin2 and Tsung-Han Lee1,*
1Department of Life Sciences, National Chung-Hsing University, Taichung, Taiwan 402
2Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan 114
Yu-Ching Wu, Li-Yih Lin and Tsung-Han Lee (2003) The abundance and location of the branchial Na+,K+,2Cl--cotransporter
(NKCC) were examined in freshwater- and seawater-adapted tilapia.
Immunoblots revealed 4 bands with molecular masses centered at 282,
208, 122, and 105 kDa, respectively. Gill NKCC in tilapia is
upregulated after seawater adaptation. Confocal laser scanning
micrographs showed that in seawater-adapted tilapia, NKCC as well as
Na,K-ATPase exhibited identical diffuse distribution confined to the
basal portion of branchial mitochondria-rich cells. However, in
freshwater-adapted tilapia, NKCC was displayed only in the apical
region of Na,K-ATPase-immunoreactive cells. Polarized distribution of
NKCC makes it a novel marker for recognizing freshwater- or
seawater-type MR cells in euryhaline tilapia.
Key words: NKCC, Teleosts, Branchial epithelium, Chloride cells.
*Correspondence: Tel: 886-4-22856141. Fax: 886-4-22851797. E-mail: thlee@dragon.nchu.edu.tw
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