基于Genome mining技术研究抑制表皮葡萄球菌生物膜形成的次级代谢产物

The biofilm infection of Staphylococcus epidermidis is now increased to top 4 in the hospital bacterial infections, moreover bacteria in the biofilm are resistant not only to antibiotics, but also to bactericidal effect of antibodies. In preliminary studies, we have found that there is correlation between secondary metabolites and biofilm formation. This project aims to use genome-mining approach to study the genome sequences of Staphylococcus epidermidis and find gene clusters related to the biosynthesis of secondary metabolites, and further use knockout technology to get gene deletion strains. Effect of the mutant on the biofilm formation was examined by a semi-quantitative microplate assay, on the other hand, more importantly, the secondary metabolites correlation with biofilm formation were found by comparing the HPLC fingerprint of wild strain with biofilm-negative mutant. This project will provide the basis to study the key enzymes in the biosynthetic pathways of these probe compounds and further discover a new target to control biofilm formation, and lay the foundation for the R & D of new drugs treatment of Staphylococcus epidermidis biofilm infection.

表皮葡萄球菌极其耐药的生物膜感染现已上升为医院细菌感染的前4位。本项目在前期发现次级代谢产物和生物膜形成具有相关性的基础上，旨在通过Genome mining技术寻找表皮葡萄球菌全基因谱中与次级代谢产物生物合成相关的基因簇，运用基因敲除技术得到基因敲除的突变株，一方面研究突变株是否易产生生物膜，从而确定与生物膜形成相关的基因簇；另一方面更重要的是对生物膜阴性突变株与生物膜阳性野生株的次级代谢产物进行比较，运用化学方法分离纯化和结构鉴定，从而确定与生物膜形成相关的探针化合物。本基础研究成果将为研究这些探针化合物生物合成的关键酶，并进一步发现控制生物膜形成的新靶点提供依据，也为研发治疗表皮葡萄球菌生物膜感染的新药奠定了基础。

本项目在前期发现次级代谢产物和生物膜形成具有相关性的基础上，通过Genome mining 技术寻找表皮葡萄球菌全基因谱中与次级代谢产物生物合成相关的基因簇，运用基因敲除技术得到磷酸泛酰巯基乙胺基转移酶(phosphopantetheinyl transferases，PPTases)基因敲除的表皮葡萄球菌的突变株(Staphylococcus epidermidis 1457-pptase)；在对突变株和野生株的次级代谢产物进行比较，发现了与PPTases相关的次级代谢产物j，进一步对野生株的次级代谢产物运用化学方法分离纯化，已对6个化合物完成了结构鉴定。本项目资助已发表SCI论文2篇，另1篇在审稿。