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  • 學位論文

以多源基因體與多源轉錄體方法研究食葉性白面鼯鼠 (Petaurista alborufus lena)的消化道微生物菌群結構與功能

Using metagenomic and metatranscriptomic approaches to study the composition and function of the gut microbiota in the leaf-eating flying squirrel (Petaurista alborufus lena)

指導教授 : 于宏燦

摘要


白面鼯鼠分布於台灣中高海拔森林中,主要以各種闊葉樹木的嫩葉為食。膨大的盲腸為其消化道的明顯特徵,內含有大量的共生微生物,可協助宿主進行食物的分解代謝,使得飛鼠能從營養貧乏的葉片中獲取生存所需的能量。儘管消化道微生物對於人體與實驗鼠的重要性已被廣泛驗證,然而對於微生物在野生動物體內的組成結構與其所扮演的功能角色仍然所知有限。因此,本研究採用非傳統培養之分子遺傳工具與新一代的定序技術,針對野生飛鼠的消化道微生物進行詳盡的探索分析。依據實驗方法與討論內容可分為三個研究主軸:一、使用16S rRNA基因序列,研究來自12個消化道樣本(分別為兩隻飛鼠的小腸/盲腸/大腸之腸壁和內容物)的細菌組成結構〈詳見第二章〉。二、使用fosmid 端點定序序列,研究飛鼠盲腸內容物的微生物菌種組成和功能特性〈詳見第三章〉。三、使用多源基因體(metagenome)和多源轉錄體(metatranscriptome)序列,研究飛鼠盲腸微生物之代謝表現特徵〈詳見第四章〉。菌群分析結果顯示:無論採取哪種研究方式,Firmicutes均為飛鼠消化道微生物中主要的優勢菌群。功能比對結果顯示:微生物的代謝功能對於消化道環境內各項營養循環具有重要貢獻,例如:碳水化合物的降解、蛋白質的循環利用、及維生素的生合成。基因表現結果顯示:各項有關醣類代謝利用的基因(包含分解/偵測/運輸醣類之基因)均被大量的表現於飛鼠的盲腸環境中,表示這些居住在小型食葉性哺乳動物體內的微生物菌群,已經適應出能夠有效地從植物葉片中獲取能量之功能特化,與宿主形成共演化關係。

並列摘要


White-faced flying squirrels (Petaurista alborufus lena) inhabiting in subtropical forests of Taiwan, feed on leaves of diverse tree species. The predominant feature of their gastrointestinal tracts is an enlarged cecum that serves as an anaerobic container for microbial fermentation. Symbiotic gut microorganisms providing metabolic activities lacking in the host, are essential for energy extraction from the nutritionally poor diet. Although the importance of gut microbiota has been well demonstrated in humans and lab mice, there is a paucity of knowledge regarding gut microbial constituents and their functional capabilities in wild animals. Therefore, in this research, we applied culture-independent molecular tools and high-throughput sequencing techniques to provide the comprehensive understanding of the gut microbial communities in the wild-caught flying squirrels. Chapter 2 described the bacterial communities of various gut compartments based on 16S rRNA gene sequences. Chapter 3 provided the phylogenetic and functional profiles of the cecal microbiota based on fosmid end-sequences. Chapter 4 revealed the metabolic characteristics of the cecal microbiota based on the comparison of metagenomic and metatranscriptomic sequences. No matter using which approaches, Firmicutes was the predominant group of the gut microbiota. All results indicated that the microbial functions greatly contributed to nutrient cycling (including degradation of carbohydrates, metabolism of proteins, and synthesis of vitamins) in the gut environments. High gene expression for sugar degradation, detection and uptake revealed microbial adaptations for plant biomass usage in small folivorous mammals.

參考文獻


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被引用紀錄


劉勃佑(2014)。植食性哺乳動物消化道之代謝體學研究〔碩士論文,國立臺灣大學〕。華藝線上圖書館。https://doi.org/10.6342%2fNTU.2014.00865

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