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  • 學位論文

單磷酸腺苷活化蛋白激酶對白蝦免疫抗病及肝醣代謝之研究

Study of adenosine 5’-monophosphate activated protein kinase on the immunity, disease resistance and glycolysis of white shrimp, Litopenaeus vannamei

指導教授 : 劉俊宏

摘要


單磷酸腺苷活化蛋白激酶 (Adenosine 5’-monophosphate activated protein kinase, AMPK)是一種高度保守的真核蛋白,在哺乳動物體內其為能量代謝的總開關,當細胞缺乏能量時會被激活,而被激活的AMPK會透過抑制糖酵解、蛋白質合成和脂質生成來減少三磷酸腺苷 (Adenosine triphosphate, ATP)的消耗,且增加葡萄糖攝取、脂質氧化抑制膽固醇合成來獲得細胞所需的能量。然而目前關於AMPK調控白蝦的免疫抗病力及肝醣代謝的機制仍不清楚,因此本研究將利用注射dsRNA來靜默白蝦的AMPK基因,並分析白蝦的抗病力、免疫力、mTOR相關基因與醣類代謝基因,以了解AMPK在白蝦體內所扮演的角色,在抗病力和免疫力的結果顯示,以dsAMPK沉默白蝦AMPK基因經24小時後,能夠降低白蝦受弧菌感染的累積死亡率,提高RBs、LYZ和PA的活性,而SOD活性則是下降的。除此之外,當抑制白蝦的AMPK基因會使Rheb基因上升,並激活mTORC1複合體進而促使下游缺氧誘導因子HIF-1α、蛋白質合成相關酵素S6K和脂質合成相關基因Lipin-1增加。本實驗研究結果顯示白蝦AMPK基因被沉默後在肝胰腺中mTOR相關基因的表現較為明顯,而血球細胞中AMPK基因雖然會隨著dsRNA的抑制表現量也有所下調,但在mTOR相關基因表現則無明顯影響。從糖解作用來看,當白蝦AMPK基因被靜默後,會使血淋巴葡萄糖和肝胰腺肝醣表現提高,同時參與糖酵解之酵素己醣激酶、磷酸果醣激酶和丙酮酸激酶表現也有所提高。因此,綜合上面的結果顯示,靜默白蝦AMPK基因能夠提升白蝦在免疫抗病力及肝醣代謝上的能力。

並列摘要


Adenosine 5'-monophosphate-activated protein kinase (AMPK) is a highly conserved eukaryotic protein responsible for energy metabolism in mammals and is activated when cells lack energy. Activated AMPK reduces the consumption of adenosine triphosphate (ATP) by inhibiting glycosis, protein synthesis, and lipid production, increasing glucose uptake and lipid oxidation, and inhibiting cholesterol synthesis from obtaining energy required by cells. However, the mechanism by which AMPK regulates immune resistance and glucose metabolism in the hepatopancreas of white shrimp is still unclear. In this study, the AMPK gene was silenced by injecting dsRNA into white shrimp to analyze disease resistance and immunity. In addition, the mammalian target of rapamycin (mTOR) and other carbohydrate metabolism-related genes were used to understand the role of AMPK in white shrimp. The disease resistance and immunity results showed that silencing AMPK gene with dsAMPK after 24 hours can reduce white shrimp infected with Vibrio. The cumulative mortality from infection increased the activity of RBs, LYZ, and PA, while SOD activity decreased. In addition, silencing the AMPK gene increased the Rheb gene and activated the mTORC1 complex, thereby promoting the increase of the downstream glycolysis gene HIF-1α, protein synthesis gene S6K and lipid synthesis related gene Lipin-1., and decreasing protein translation of the 4E-BP gene. This experimental study showed that the expression of mTOR-related genes in the hepatopancreas was more evident after the AMPK gene was silenced in white shrimp. Although the AMPK gene in hemocyte was down-regulated with the inhibition of dsRNA, the expression of mTOR-related genes in the hepatopancreas was higher than that of mTOR-related genes in the hemocyte with no significant difference. In terms of glycolysis, when the AMPK gene was inhibited, the expression of glucose in the hemolymph and hepatopancreas was improved. The expression of glycolysis by-products hexokinase, phosphofructokinase and pyruvate kinase were also improved. Therefore, these results show that the AMPK gene negatively regulates immune response and glucose metabolism in the hepatopancreas of white shrimp.

參考文獻


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