中文摘要：

目的：对小劈碱（BBR）对大肠杆菌的抑制作用的分子靶点进行探讨。方法：鉴于BBR对DNA结合的偏好性,本文从基因转录表达水平对BBR的大肠杆菌生长抑制作用靶点进行实验研究。结果：BBR对于大肠杆菌基因上游调控元件UP element具有较强的亲和力,而在此元件地转录起始区含有TATA碱基序列。进一步对启动子上游含有UP element调控元件的基因sulA、recA、16S和启动子上游不含UP element调控元件的基因lpxC、secG、mutT的mRNA表达比较表明,BBR抑制sulA、recA、16S的表达,对lpxC、secG、mutT无明显作用,提示TATA序列是BBR的作用靶点。结论：本结果对从基因转录水平探讨BBR抑菌作用提供了新思路。

英文摘要：

There have been many reports on berberine （BBR） effect of the inhibition on gut bacteria, but more from the protein level. In view of the preference of BBR for DNA binding, we here investigated the expression of BBR from the transcriptional expression level of the gene. The resuhs showed that BBR had a higher affinity for UP element of Escherichia coli （E. coli） gene, and the transcription initiation region of this element contained TATA base sequence. The expression of genes sulA, recA and 16S which contain the genes of the UP element regulatory elements in the upstream of the promoter could be suppressed by BBR, and the expression of lpxC, secG and mutt which did not contain the genes of the UP element regulatory elements in the upstream of the promoter could not be inhibited by BBR. It is shown that the TATA sequence is the target of BBR. This result provides a new perspective for exploring the effect of BBR＇s inhibition of microbiota from gene transcription.