科研之友
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摘要
The present study aimed to evaluate the osmoregulatory mechanism of Daisy's medaka, O. woworae, as well as demonstrate the major factors affecting the hypo-osmoregulatory characteristics of euryhaline and stenohaline medaka. The medaka phylogenetic tree indicates that Daisy's medaka belongs to the celebensis species group. The salinity tolerance of Daisy's medaka was assessed. Our findings revealed that 20 parts per thousand (hypertonic) saltwater (SW) was lethal to Daisy's medaka. However, 62.5% of individuals survived 10 parts per thousand (isotonic) SW with pre-acclimation to 5 parts per thousand SW for one week. This transfer regime, "Experimental (Exp.) 10 parts per thousand SW", was used in the following experiments. After 10 parts per thousand SW-transfer, the plasma osmolality of Daisy's medaka significantly increased. The protein abundance and distribution of branchial Na+, K+-ATPase (NKA) and Na+, K+, 2Cl(-) cotransporter 1 (NKCC1) were also examined after transfer to 10 parts per thousand SW for one week. Gill NKA activity increased significantly after transfer to 10 parts per thousand SW. Meanwhile, elevation of gill NKA aa-subunit protein-abundance was found in the 10 parts per thousand SW-acclimated fish. In gill cross-sections, more and larger NKA-immunoreactive (NKA-IR) cells were observed in the Exp. 10 parts per thousand SW medaka. The relative abundance of branchial NKCC1 protein increased significantly after transfer to 10 parts per thousand SW. NKCC1 was distributed in the basolateral membrane of NKA-IR cells of the Exp. 10 parts per thousand SW group. Furthermore, a higher abundance of NKCC1 protein was found in the gill homogenates of the euryhaline medaka, O. dancena, than in that of the stenohaline medaka, O. woworae.
- 出版日期2016-8
- 单位中国医科大学
