| Summary: | 碩士 === 國立臺灣海洋大學 === 食品科學系 === 97 === Grouper (Epinephelus coioides) is highly valuable in the aquaculture industry and is amounted to the large types in demand of seafood consumption in Taiwan. Using proteomic approach, this thesis sets two research goals on analyzing the white muscle proteomes of groupers fed by different diets. The first is to understand the biological implications of some differentially expressed proteins, the second is to find proteins with functionality, eventually would help the grouper related industry. Experimental materials included groupers fed by diets composed of different protein contents (500 g/kg and 350 g/kg) and protein sources (control and Basal) grown for one year. Previously, the ratio of successful grouper protein identification was hampered by poor 2-DE gel resolutions. This study uses 17 cm IPG strips to substitute for 7 cm IPG strip and increases identified spots into 31 species. Moreover, final concentration of 7M urea and 2M thiourea were added into the rehydration buffer that increased the resolution of 2-DE gel. 2D-mapping demonstrated that there are three new creatine kinases (CKM3, M-type, muscle isoform 2) in grouper muscle expressed differently responding to protein diets. CKM3 protein expression was up- regulated in the 350 g/kg feeding group. In contrast, muscle isoform 2 was down-regulated. The Basal group, on the other hand, M-type protein expression was up-regulation, but CKM3 expression was down-regulated. Furthermore, soluble adenylyl cyclase was expressed only in 350 g/kg feeding group and the Basal group, and its quantity in the basal group was significantly higher than in 350 g/kg protein group. It showed the two diets provide insufficient energy for metabolism and need to activate this enzyme for energy production. Interestingly, a glycolytic enzyme triosephosphate isomersae B was up-regulated in the Basal group compared with other groups, which implies that as fish obtained more energies, it causes triosephosphate isomerase B to increase as well as produce more acidic proteins. We also found the emergence of a new spot on the right side of tropomyosin spot in 2-DE gel, which indicates that a novel protein was induced under insufficient energy condition. Since this new protein was only expressed in the Basal group, it has the potential to be the biomarker for monitoring Epinephelus coioides feeding diets when different protein source is replaced for energy metabolism.
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