Electroactive microorganisms from mouse feces

The gut microbiome is not only an indicator of different pathologies, but it also controls the health of the host. Recently, microorganisms inherent to the gut microbiome, such as Listeria monocytogenes and Clostridium cochlearium, were demonstrated to be electroactive that is to perform extracellular electron transfer (EET). To further explore the role of EET in the gut microbiome the first electrochemical enrichment starting from mouse feces was performed. Open circuit, abiotic and autoclaved inoculum controls were run in parallel. The presence of electroactive anodic biofilms was demonstrated using fluorescence microscopy and cyclic voltammetry. The 16S rRNA gene sequencing and PCR-free Nanopore sequencing showed the enrichment and dominance of Shigella flexneri.

肠道微生物组不仅是多种病理状态的指示标志物，同时也调控宿主的健康状况。近期研究证实，肠道微生物组固有微生物——如单核细胞增生李斯特菌（Listeria monocytogenes）与耳蜗梭菌（Clostridium cochlearium）——具有电活性，即能够执行胞外电子转移（extracellular electron transfer, EET）。为进一步探究胞外电子转移在肠道微生物组中的作用，本研究开展了首例以小鼠粪便为接种物的电化学富集培养实验。实验同步设置了开路对照、无生物对照以及高压灭菌接种物对照。通过荧光显微镜与循环伏安法，证实了电活性阳极生物膜的存在。16S rRNA基因测序与无PCR扩增纳米孔（Nanopore）测序结果显示，弗氏志贺菌（Shigella flexneri）实现了富集并成为优势菌群。