Department of Gastrointestinal Microbiology, German Institute of Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany.
J Appl Microbiol. 2018 Jan;124(1):220-231. doi: 10.1111/jam.13616. Epub 2017 Dec 7.
To identify human subjects harbouring intestinal bacteria that bioactivate daidzein to equol using a targeted PCR-based approach.
In a pilot study including 17 human subjects, equol formation was determined in faecal slurries. In parallel, faecal DNA was amplified by PCR using degenerate primers that target highly conserved regions of dihydrodaidzein reductase and tetrahydrodaidzein reductase genes. PCR products of the expected size were observed for six of the eight subjects identified as equol producers. Analysis of clone libraries revealed the amplification of sequences exclusively related to Adlercreutzia equolifaciens in four of the subjects tested positive for equol formation, whereas in three of the equol producers, only sequences related to Slackia isoflavoniconvertens were observed. No amplicons were obtained for one equol-forming subject, thus suggesting the presence of nontargeted alternative genes. Amplicons were only sporadically observed in the nonequol producers.
The majority of human subjects who produced equol were also detected with the developed PCR-based approach.
The obtained results shed light on the distribution and the diversity of known equol-forming bacterial species in the study group and indicate the presence of as yet unknown equol-forming bacteria.
采用基于靶向 PCR 的方法，鉴定能够将大豆苷元生物转化为黄豆苷元的肠道细菌的人类宿主。
在一项包括 17 名人类受试者的初步研究中，通过粪便匀浆来确定黄豆苷元的形成情况。同时，使用针对二氢大豆苷元还原酶和四氢大豆苷元还原酶基因高度保守区域的简并引物，通过 PCR 扩增粪便 DNA。在确定为黄豆苷元生成者的 8 名受试者中的 6 名中观察到了预期大小的 PCR 产物。对阳性结果的 4 名受试者的克隆文库进行分析，发现仅扩增出与 Adlercreutzia equolifaciens 相关的序列，而在 3 名黄豆苷元生成者中，仅观察到与 Slackia isoflavoniconvertens 相关的序列。有一名黄豆苷元生成者未获得扩增子，这表明可能存在非靶向替代基因。非黄豆苷元生成者中仅偶尔观察到扩增子。
使用开发的基于 PCR 的方法检测到产生黄豆苷元的大多数人类宿主。
研究结果阐明了研究组中已知黄豆苷元生成细菌的分布和多样性，并表明存在尚未知的黄豆苷元生成细菌。
