氧化葡萄糖酸杆菌SCB329基因组的大小与结构的研究

收集维生素C产生菌氧化葡萄糖酸杆菌GluconobacteroxydansSCB32 9的纯培养对数期的菌体 ,采用凝胶包埋法制备完整染色体 ,用稀有酶切位点的限制性内切酶和脉冲场电泳技术对SCB32 9的基因组进行了分析 ,SpeⅠ (5′ ACTAGT)酶切有 2 4个片段 ,其大小从 1 0kb到32 0kb,用XbaⅠ (5′ TCTAGA)酶切产生 40个片段 ,其大小从 4kb到 2 0 0kb,综合两种限制酶酶切片段长度的总和结果 ,SCB32 9基因组大小为 2 70 0kb,SCB32 9基因组由一条 2 50 0kb的染色体和一个 2 4 5kb的质粒组成。通过用脱氧核糖核酸酶Ⅰ和S1核酸酶处理其基因组后电泳证实SCB32 9的染色体和质粒的拓扑学结构均为环状

STUDLES ON THE GENOME SIZE AND STRUCTURE OF GLUCONOBACTER OXYDANS SCB329

In the "Two-step fermentation" of Vitamin C synthesis, Gluconobacter oxydans SCB329 is responsible for the production of 2-keto-L-gulonic acid (2-KLG), which is an important precuror of vitamin C synthesis. The intact chromosome was prepared from logarithmic phase cells by agaraseembedded method and was analysized by restriction endonucleases and contour-clamped homogeneous electric field pulsed-field gel electrophoresis (PFGE). Spe I (5-ACTAGT) produced 24 fragments, ranging in size from 10 to 320 kilobases (kb). Xba I (5-TCTAGA) yielded 40 fragments (4 to 200 kb). A total genome size of approximately 2,700 kb was determined by summing the fragment length. Analysis of the entire genome of SCB329 by PFGE revealed that the genome of SCB329 consist of a chromosome which is 2,500 Kb in length and a large plasmid which is 245 kb. After linearization of the DNA by DNase I and S1 nuclease, in contrast with the band which can not be viewed, the band of chromosome and plasmid were appeared, this suggest that structure of the chromosome and the plasmid were circular.