荷斯坦奶牛瘤胃微生物元基因组BAC文库的构建与分析

Construction and analysis of rumen bacterial artificial chromosome library from a dairy cow rumen microflora

采用未培养技术和脉冲场电泳技术直接从瘤胃微生物提取到大小在2Mb左右混合微生物DNA,经HindⅢ不完全酶切获得50～100kbDNA片段,将其连接在pCC1BAC载体上,转化E.coliEPI300,得到瘤胃微生物BAC文库,经对文库的鉴定分析,该文库的平均插入片段54.5kb,空载体率小于2%,库容837Mb,共保存15360个克隆。通过对该文库进行部分酶活性筛选,获得具有淀粉酶活性的克隆16个;纤维素酶活性的克隆26个,而且能降解纤维素的克隆中25个呈现多酶活性。这些结果表明该文库具有重要研究价值。

The high molecular weight DNA was extracted and purified directly from rumen samples in the study by using culture-independent and pulsed field gel electrophoresis approaches. After digestion with Hind Ⅲ, DNA fragments ranging from 50-100kb was collected and ligated to pCC1BAC vector. The ligation mixture was transformed into E. coli EPI300 and a rumen metagenomic BAC library with about 15360 clones was constructed. The average insert size is about 54.5kb, mostly ranging from 50-70kb, and the capacity of this BAC library is about 837Mb. Several BAC clones with activity of amylase, Cmcellulase had been screened from the BAC library. The clones with Cmcelluase activity were screened further for linchenase, xylanase, cellobioase activity and the result is that 25 of them have at least one kind of other enzyme activity.