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標題: | 臺灣藍舌病病毒segment 7基因組及胺基酸之序列分析 Analysis of Genome Segment 7 and Amino Acid Sequence of Bluetongue Virus in Taiwan |
作者: | Hao-Che Yen 顏浩哲 |
指導教授: | 王汎熒(Fun-In Wang) |
關鍵字: | 藍舌病,第七段基因組,第七病毒蛋白,基因組序列比對, bluetongue,segment 7,VP7,genome alignment, |
出版年 : | 2018 |
學位: | 碩士 |
摘要: | 藍舌病(BT)是經由庫蠓傳播的反芻動物病毒性疾病,對經濟及野生反芻獸皆有感受性,進而造成全世界畜牧業嚴重的經濟損失。過去的研究指出藍舌病病毒(BTV)在台灣的反芻獸通常呈現無症狀的亞臨床感染,並分別在金門和屏東地區分離出2株病毒。基因組分析顯示這2個分離株在segment 7上出現了正向選擇(positive selection)。基因segment 7轉譯成最外圍的核心蛋白質VP7,是在病毒進入昆蟲細胞時不可或缺的蛋白質之一,這些證據顯示BTV可能會為了適應台灣的環境而演化。自從18000年前冰河時期結束以來,台灣島便與其他亞洲陸塊分離,島上生物因而演化出許多特有種,其中也包括了數種有機會傳播BTV的庫蠓屬昆蟲。本研究的假說是台灣特有的庫蠓屬昆蟲在傳播藍舌病時提供了BTV基因segment 7演化壓力。研究目的在於調查目前在台灣島流行的BTV病毒株及其分佈。以競爭型酵素結合免疫吸附法檢測在台灣各地區採集的牛羊血清中是否有BTV-VP7特異性抗體,結果顯示牛的血清陽性率為26.7%,山羊為18.6%。以RT-PCR檢測牛羊抗凝全血樣本中的BTV-VP1核酸訊號,其中山羊檢體中有9個陽性樣本,而使用OIE推薦之BTV-NS1引子,所有檢體均呈現陰性。為了分離病毒,將數個核酸陽性的全血樣本接種至雞胚胎和BHK21細胞株,但未能分離到新的病毒株。本研究中亦比較了台灣、日本、中國、印度、澳大利亞等鄰近地區BTV病毒株的VP7胺基酸序列,發現在台灣及日本株有3個特定位置的氨基酸與其他地區分離株不同,這些變異位於VP7三聚體結構上的相鄰位置,而且是台灣株BTV2和BTV12以及日本株獨有的,這個發現揭示了BTV在鄰近地區間演化的過程中,為了適應當地庫蠓時VP7可能扮演的角色。 Bluetongue (BTV) is an arthropod-borne disease, in domestic and wild ruminants, caused by bluetongue virus (BTV), and leads to great economic loss worldwide. Previous studies showed BTV infection in Taiwan was often subclinical, and 2 viruses had been isolated from specimens in Kinmen and Pingtung districts, respectively. Genetic analysis of the 2 isolates showed a positive selection of segment 7, suggested that BTV might evolve and adapt when entering Taiwan as a new environment. Genome segment 7 encodes an outermost core protein, VP7, which is the most accessible protein of the BTV core that may participate in cell entry. Taiwan is geographically isolated for a long period of time since the end of last ice age 18000 years ago, and inhabited by several endemic vector species, including Culicoides, the vector of BTV. The hypothesis is that these endemic Culicoides species in Taiwan provide an evolution pressure to BTV, especially on genome segment 7. The aim of the project was to investigate the new viral strains and the distribution of these strains on Taiwan. Blood samples were collected from different districts in Taiwan. ELISA tests were performed for anti-BTV group specific antibody revealing seropositive rates of 26.7% in cattle by heads, and 18.6% in goats. BTV nucleic acid in whole blood was detected via RT-PCR targeted on VP1 segment revealed 9 positive samples from goat. Detection via RT-PCR target on NS1segment revealed negative in all samples. A few RT-PCR positive blood samples were selected for viral isolation via inoculation into chicken embryos and BHK21 cell line but failed to isolate new virus strain. Sequence alignment of Taiwan BTV isolates VP7 with isolates from neighboring areas including Japan, China, India and Australia showed 3 specific amino acids, that are unique to Taiwan BTV2 and BTV12 and Japan isolates, located close by on the three-dimensional model of VP7 trimer, suggesting the role of VP7 in BTV evolution in local Culicoides vector species in these geographically neighboring areas. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/79135 |
DOI: | 10.6342/NTU201802556 |
全文授權: | 有償授權 |
電子全文公開日期: | 2023-08-09 |
顯示於系所單位: | 分子暨比較病理生物學研究所 |
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