Department of Medical Microbiology, University Medical Center Groningen, University of Groningen, The Netherlands.
ISME J. 2012 Aug;6(8):1578-85. doi: 10.1038/ismej.2012.5. Epub 2012 Feb 23.
Faecalibacterium prausnitzii is one of the most abundant bacteria in the human gut ecosystem and it is an important supplier of butyrate to the colonic epithelium. Low numbers of faecalibacteria have been associated with inflammatory bowel disease. Despite being extremely oxygen sensitive, F. prausnitzii is found adherent to the gut mucosa where oxygen diffuses from epithelial cells. This paradox is now explained on the basis of gas tube experiments, flavin-dependent reduction of 5,5'-dithiobis-2-nitrobenzoate and microbial fuel cell experiments. The results show that F. prausnitzii employs an extracellular electron shuttle of flavins and thiols to transfer electrons to oxygen. Both compounds are present in the healthy human gut. Our observations may have important implications for the treatment of patients with Crohn's disease, for example, with flavin- or antioxidant rich diets, and they provide a novel key insight in host-microbe interactions at the gut barrier.
普拉梭菌（Faecalibacterium prausnitzii）是人类肠道生态系统中最丰富的细菌之一，也是结肠上皮丁酸的重要供应者。肠道中普拉梭菌数量较少与炎症性肠病有关。尽管普拉梭菌对氧气极其敏感，但它被发现黏附在肠道黏膜上，而氧气从肠上皮细胞扩散到这里。现在，基于气室实验、黄素依赖性还原 5,5'-二硫代双-2-硝基苯甲酸（5,5'-dithiobis-2-nitrobenzoate）和微生物燃料电池实验，对这一悖论做出了解释。结果表明，普拉梭菌利用黄素和巯基的细胞外电子穿梭体将电子传递给氧气。这两种化合物都存在于健康的人类肠道中。我们的观察结果可能对治疗克罗恩病患者具有重要意义，例如，采用富含黄素或抗氧化剂的饮食，这为肠道屏障的宿主-微生物相互作用提供了新的关键见解。
