基于功能宏基因组学技术的金黄色葡萄球菌生物被膜抑制物的发现与活性分析

Discovery and analysis of Staphylococcus aureus biofilm inhibitors using functional metagenomics approach

摘要:

宏基因组学方法直接提取环境中的全部微生物基因组DNA，并使其得到功能性表达，为微生物天然产物的开发利用提供了新的方法。利用功能宏基因组学技术，使用大肠杆菌-链霉菌穿梭载体构建四川峨眉山土壤宏基因组文库，并将文库菌中所携带的环境DNA接合转移到链霉菌宿主中。通过活性筛选获得两个具有抗菌活性的阳性链霉菌克隆，其发酵粗提物对金黄色葡萄球菌生物被膜的形成均有很好的抑制作用，当浓度达到2 MIC (Minimum inhibitory concentration) 时，抑制作用超过90%；同时，两种粗提物样品对金黄色葡萄球菌生物被膜也存在显著的清除作用，其中EM110样品对金黄色葡萄球菌生物被膜的清除率高于EM123样品。本文通过功能宏基因组学技术，直接从土壤中筛选获得了对金黄色葡萄球菌生物被膜有较强抑制及清除作用的活性物质。

Abstract:

Although most microbes are not readily cultured in the lab, microbial DNA can be extracted directly from an environmental sample and be functionally expressed in a suitable host for natural products discovery, and this approach has been termed “metagenomics”. An E’mei Mountain soil metagenomic library was constructed using an Escherichia coli-Streptomyces shuttle vector for functional based screening of anti-bacterial clones in Streptomyces albus host. Two active clones were obtained and their fermentation broths were studied for the inhibitory effect on Staphylococcus aureus biofilm. Their fermentation products have a good inhibitory effect on the formation of S. aureus biofilm, and the inhibitory effect could exceed 90% when the concentration of sample was 2 MIC (Minimum Inhibitory Concentration). In addition, two samples had significantly effect on S. aureus biofilm dispersal, and the clearance rate of EM110 was higher than EM123. In conclusion, substances with strong bioactivities on biofilm formation and dispersal of S. aureus could be discovered by using metagenomics technology.