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標題: | 馬尼拉小繭蜂多去氧核糖核酸病毒調節斜紋夜蛾之細胞外腺苷以抑制寄主免疫系統 Snellenius manila bracovirus regulates the extracellular adenosine levels in Spodoptera litura to suppress host immune system |
作者: | Yuan Chang 張園 |
指導教授: | 吳岳隆(Yueh-Lung Wu) |
關鍵字: | 細胞外腺?,能量轉換,多去氧核糖核酸病毒,寄生蜂,免疫抑制, extracellular adenosine,energy tranduction,polydanvirus,parasitoid,immunosuppression, |
出版年 : | 2019 |
學位: | 碩士 |
摘要: | 啟動免疫系統需要大量的能量,因此當受到病原菌感染時,生物會傾向重新分配儲存和生長發育中的能量。最近在黑腹果蠅 (Drosophila melanogaster) 相關的研究顯示,果蠅幼蟲受到寄生蜂或細菌感染時,幼蟲體內的細胞外腺苷含量增加,引起下游生長發育組織和免疫細胞之間的能量代謝轉換,並影響受感染幼蟲生長發育,而這樣的能量轉換有益於免疫系統對抗外來病原菌。細胞外腺苷是能量代謝轉換的訊號,可作為代謝轉換開關增加細胞內的醣解作用及脂肪體中將葡萄糖轉化為海藻糖並釋放到循環系統中的含量以促進免疫細胞的分化並啟動免疫反應。多去氧核醣核酸病毒為馬尼拉小繭蜂的共生病毒,只能在小繭蜂的卵萼細胞中複製。當馬尼拉小繭蜂將卵產至斜紋夜蛾體內時,多去氧核醣核酸病毒之病毒顆粒也會伴隨著卵進到寄主體內並抑制寄主的免疫系統。我們的研究發現多去氧核醣核酸病毒能影響寄主的腺苷含量。此外,受多去氧核醣核酸病毒感染後,斜紋夜蛾之腺苷受體和腺苷脫氨酶相關生長因子的基因表現量及腺苷含量顯著下降。斜紋夜蛾之醣類代謝過程也受腺苷信號傳遞的影響,這些結果證明多去氧核醣核酸病毒通過調節腺苷的含量以影響寄主的免疫反應。外加腺苷的實驗證明腺苷可以提高寄主的免疫反應並降低小繭蜂的寄生率。研究結果顯示,多去氧核醣核酸病毒可藉由抑制腺苷信號傳遞來抑制寄主之免疫反應。而這樣的發現在未來可以提供蟲害防治一個新的觀點,有機會將腺苷應用於生物防治,包含開發抑制腺苷路徑的藥物,降低害蟲免疫反應,以增加蟲害防治的效力。 Immune systems require enormous amounts of energy, so organisms tend to redistribute energy from storage and development functions when infected by pathogens. Recent studies in Drosophila melanogaster also indicated that increased extracellular adenosine upon wasp or bacterial infection induces the metabolic switch between developmental tissues and immune cells, which slows down the development of infected larvae but benefits the immune system against pathogens. Extracellular adenosine is a energy signal that mediates the metabolic switch to increase cellular glycolysis, allowing the fat body to convert glucose to trehalose, which is then released to the circulation systems to facilitate immune cell differentiation and activate immune responses. Polydnaviruses (PDVs) are parasitoid symbionts that only replicate in calyx cells of the wasp. When the parasitoid Snellenius manila injects its eggs into a host, its associated bracovirus (Snellenius manila bracovirus, SmBV) are also spread into Spodoptera litura. Thus, the immune system of the host is suppressed by the SmBV. We found that SmBV affects adenosine levels and immune responses. Moreover, after SmBV infection, gene expression levels of adenosine receptor and adenosine deaminase-related growth factor in S. litura were significantly reduced. Additionally, carbohydrate metabolism was affected by adenosine signaling, leading to significant decreases in immune responses, proving that SmBV affects host immune responses through regulation of adenosine content. Injection of artificial adenosine increased host immunity and significantly lowered parasitism rates. Our study showed that PDV can inhibit immune responses through inhibition of adenosine signaling. This result might bring a breakthrough for enhance pest control by using adenosine inhibitors to suppress immune responses of pests. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/74412 |
DOI: | 10.6342/NTU201901145 |
全文授權: | 有償授權 |
顯示於系所單位: | 昆蟲學系 |
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