大肠杆菌Nissle 1917的多组学分析及其产微菌素的功能验证

Multiomics analysis of Escherichia coli Nissle 1917 and functional validation of microcin

【目的】探究益生大肠杆菌Nissle 1917(Escherichia coli Nissle 1917,EcN)与模式菌株的代谢及转录差异,为构建工程菌株EcN提供参考,进一步推动食品安全菌株EcN的应用。【方法】软件分析比较EcN和模式菌株BL21(DE3)、W3110的基因组、转录组差异,并通过质粒构建表达验证;在BL21(DE3)中质粒表达EcN来源的微菌素(microcin)并进行抑菌效果验证。【结果】共挖掘出904个差异编码基因。同时以不同碳源为底物分析验证了不同菌株在碳源吸收利用方面的差异,以启动子Pflic在不同菌株中的表达情况验证了转录调控上的差异;最终构建的微菌素重组菌株在培养12 h时,抑菌率提高了30.3%。【结论】研究一定程度上阐明了EcN的代谢特性及其与模式菌株的转录差异,并为微菌素作为窄谱治疗药物来抑制肠道病原体和减少肠细菌水华的研究提供了思路。

[Objective]To compare the metabolism and transcription between the probiotic Escherichia coli Nissle 1917(EcN)and the model strains,thus providing a reference for the engineering and promoting the application of the food-safe strain EcN.[Methods]The genome and transcriptome were compared between EcN and model strains BL21(DE3)and W3110 by software,and plasmids were constructed to verify the differences.EcN-derived microcin was expressed in BL21(DE3)and the antibacterial effect of microcin was verified.[Results]A total of 904 differentially coding genes were identified.The differences in carbon source absorption and utilization of different strains were verified by experiments with different carbon sources as substrates.The expression of the promoter Pflic confirmed the differences in transcription among different strains.The recombinant strain of microcin showed an increase of 30.3%in the inhibition rate after 12 h of culture.[Conclusion]This study clarifies the metabolic characteristics of EcN and confirms the differences in transcription between EcN and model strains.Moreover,this study provides ideas for the development of microcin as a narrow-spectrum therapeutic drug to inhibit intestinal pathogens and reduce intestinal bacterial blooms.