類鼻疽伯克氏桿菌鞭毛基因體之比較

Comparison of Flagella Genomes of Burkholderia pseudomallei

類鼻疽是革蘭氏陰性類鼻疽伯克氏桿菌所引起之人畜共通疾病。鞭毛因為涉及於細菌從感染病灶擴散至遠端器官而被認為是重要的毒力因子。鞭毛由細絲樣、掛鉤樣與基體蛋白所組成，其基體蛋白位於菌體細胞壁內，細絲樣蛋白可由基體蛋白，通過掛鉤樣蛋白的中空管道而往外延伸至細胞壁外。牽動鞭毛的運動與功能至少涉及數個群聚基因，包括有合成、調節、運動、趨化、訊息傳送、啟動器與質子運動力等相關基因。為了探索類鼻疽伯克氏桿菌鞭毛相關蛋白的多樣性，本研究利用生物資訊分析類鼻疽伯克氏桿菌的鞭毛基因體。本論文分析之基因體包括有類鼻疽伯克氏桿菌1710b、1106a、k96243與668等菌株，以及一株台灣本土分離菌之vgh19菌株。藉由京都百科的分類，包括鞭毛合成、第三型分泌系統、趨化性以及其他可能與鞭毛功能有關基因等，基因體的生物資訊被擷取與分析。所有的開放式轉譯框架以及轉譯框架轉譯的蛋白質序列與蛋白質的物理化學資訊、同源相似性以及個別蛋白的修飾等，都在本研究被分析之。分析結果顯示，雖然大多數基因是非常保守，但所有的菌株都存在有數個核酸序列基本結構的差異，並且可以被重新註解。儘管替代性起始密碼、基因重疊性與特定鞭毛基因有不同的複製數目等現象，都存在於不同分析菌株的基因體中，但類鼻疽伯克氏桿菌vgh19菌株蘊含之鞭毛基因序列與蛋白主體功能，仍然相當的保守。台灣環境的分離菌vgh19菌株，雖然經過台灣環境的獨立演化，但仍然呈現鞭毛基因的保守性。

Burkholderia pseudomallei is a gram-negative rod, causing a zoonotic infection (called melioidosis). The flagellum of B. pseudomallei is recognized as a virulent factor involving in systemic dispreading of the bacteria to remote organs from infected foci. The flagellum is cosisted of filament, hook and basal body. The basal body is located at inside of cell wall while filment can outward elongate through hollow of hook from basal body. At least, several sets of clustered genes included flagellar synthesis, regulation, movement, chemotaxis, signal transduction, motor and proton motive force are involved in the function of bacterial movement. To explore the genetic diversities, the bioinformatics of flagella genomes were analyzed from differet representative strains of B. pseudomallei. Nowadays the whole gemones of B. pseudomallei 1710b, 1106a, k96243 and 668 as well as an indigenous strain of B. pseudomallei vgh19 were sequenced. By the bioinformatic analysis in which based on the catagories of Kyoto Encylopedia, the nucleotide sequences of flagella assembly, type Ⅲ secretion system, chemotaxis and other anticipated genes related to flagellar function were retrieved and analyzed. All open reading frames as well as their encoding amino acid sequences and proteomic informations including general physic and chemical characteristics, orthologous homology as well as modification of individual proteins were discussed. Our results indicated that, for genome sequences of all strains, the distinct motifs of certain genes can be annoted although the most genes were conserved. In spite of alternative initiation codons, gene overlapped and different copy numbers of flagella gene were existed in genome among comparable strains, the protein sequences and functional domains of B. pseudomallei vgh19 harbouring flagella proteins were highly conserved. We suggests that the flagella proteins of B. pspeudomallei vgh19, a unique strain in Taiwan about world, were conserved despite this strain could independently evoluted in Taiwanese environments.