碩士 / 大葉大學 / 分子生物科技學系碩士班 / 103 / Chromatophores distribution in the dermis determines the pattern and which is important functions in protection against UV irradiation, camouflage, kin recognition, shoaling and sexual selection in fish. The pigmentation is affected by the expression of coloration related genes, such as tyrosinase, tyrosinase-related protein 1/2 (TRP1/2), microphthalmia-associate transcripition factor (Mitf), sox10 and dopachrome tautomerase (Dct). These genes can induce different colors and patterns in the dermis of teleosts. Tilapia (Oreochromis mossambicus) is one of the most common commercial fish in Taiwan and they have three chromatophore types - melanophores, xanthophores and erythrophore. In our previous studies, a neuropeptide - pituitary adenylate cyclase - activating polypeptide (PACAP, tpacap38) and its receptor (tpac1-r) were found expressed in the gonad and other tissues of tilapia and involved in the cAMP-protein kinase A (PKA) signaling pathway. However, literature concerning the relationship among tilapia color patterns, chromatophores and neuropeptide is still scant. Thus, in this study, semi-quantitative RT-PCR was applied to analyze the expression of mitf, sox10, tyrosinase, Dct, tpacap38 and tpac1-r in the melanophores and erythrophores of fin after in vitro culture with different concentration of neuropeptide for different periods. The dose-dependent experiment was conducted by addition of different concentrations of ovine PACAP38 (2.5, 5.0 and 10.0 nM) to fin cultured for 2 h in vitro, and a time-course experiment was conducted with ovine PACAP38 (5.0 nM) for 0 to 8 h (2, 4, 6 and 8 h). The mRNA levels of mitf, sox10, tyrosinase, Dct, tpacap38 and tpac1-r were low at 0 h and increased significantly at 2 h, and then decreased with prolonged cultured periods in both dose-dependent and time-course experiments. Same results were found in morphological analysis and melanin assay experiments. The result of cAMP and tyrosinase analyses show that cultured with 5 nM ovine PACAP38 for 2 h, the concentration of cAMP and activity of tyrosinase increased significantly in the tail fin of tilapia. These results suggested that PACAP involves in coloration of chromatophores and in the cAMP/PKA/CREB/Mitf/Tyrosinase signaling pathway. Expression of tpacap38 in the chromatophores of fin in tilapia suggested that neuropeptide may involve in coloration in the bony fish, and that could be applied in the development of ornamental fish.
| Identifer | oai:union.ndltd.org:TW/103DYU00061003 |
| Date | January 2015 |
| Creators | Hung-Ching Chiu, 邱洪磬 |
| Contributors | Wei-Tung Huang, 黃尉東 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 86 |
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