Vázquez L, Cabrera-Rubio R, Tamames J, Mayo B, Flórez A B
Departamento de Microbiología y Bioquímica, Instituto de Productos Lácteos de Asturias (IPLA), Consejo Superior de Investigaciones Científicas (CSIC), Paseo Río Linares s/n, 33300-Villaviciosa, Asturias, Spain.
Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Avenida de Roma s/n, 33011-Oviedo, Asturias, Spain.
Benef Microbes. 2023 Feb 1;14(3):255-268. doi: 10.3920/BM2022.0027.
Among the isoflavones and isoflavone-derived metabolites, equol, which in the human gut is synthesised from daidzein by minority bacterial populations, shows the strongest estrogenic and antioxidant activity. The beneficial effects on human health of isoflavone consumption might be partially or indeed totally attributable to this equol. Although some of the bacterial strains involved in its formation have been identified, the interplay between the composition and functionality of the gut microbiota and equol producer phenotype has hardly been studied. In this study, after shotgun metagenomic sequencing, different pipelines for the taxonomic and functional annotation of sequencing data were used in the search for similarities and differences in the faecal metagenome of equol-producing (n=3) and non-producing (n=2) women, with special focus on equol-producing taxa and their equol-associated genes. The taxonomic profiles of the samples differed significantly depending on the analytical method followed, although the microbial diversity detected by each tool was very similar at the phylum, genus and species levels. Equol-producing taxa were detected in both equol producers and non-producers, but no correlation between the abundance of equol-producing taxa and the equol producing/non-producing phenotype was found. Indeed, functional metagenomic analysis was unable to identify the genes involved in equol production, even in samples from equol producers. By aligning equol operons with the collected metagenomics data, a small number of reads mapping to equol-associated sequences were recognised in samples from both equol producers and equol non-producers, but only two reads mapping onto equol reductase-encoding genes in a sample from an equol producer. In conclusion, the taxonomic analysis of metagenomic data might not be suitable for detecting and quantifying equol-producing microbes in human faeces. Functional analysis of the data might provide an alternative. However, to detect the genetic makeup of the minority gut populations, more extensive sequencing than that achieved in the present study might be required.
在异黄酮及其衍生代谢产物中，雌马酚在人体肠道中由少数细菌群体从大豆苷元合成，具有最强的雌激素活性和抗氧化活性。食用异黄酮对人体健康的有益影响可能部分或完全归因于这种雌马酚。尽管已经鉴定出了一些参与其形成的细菌菌株，但肠道微生物群的组成与功能和雌马酚产生菌表型之间的相互作用几乎没有得到研究。在本研究中，通过鸟枪法宏基因组测序后，使用不同的测序数据分类和功能注释流程，来寻找产雌马酚（n = 3）和不产雌马酚（n = 2）女性粪便宏基因组中的异同，特别关注产雌马酚的分类群及其与雌马酚相关的基因。根据所采用的分析方法，样本的分类学概况有显著差异，尽管每种工具检测到的微生物多样性在门、属和种水平上非常相似。在产雌马酚者和不产雌马酚者中均检测到了产雌马酚的分类群，但未发现产雌马酚分类群的丰度与产雌马酚/不产雌马酚表型之间存在相关性。实际上，功能宏基因组分析无法鉴定出参与雌马酚产生的基因，即使在产雌马酚者的样本中也是如此。通过将雌马酚操纵子与收集到的宏基因组数据进行比对，在产雌马酚者和不产雌马酚者的样本中均识别出了少量与雌马酚相关序列匹配的读数，但在一个产雌马酚者的样本中，只有两个读数与编码雌马酚还原酶的基因匹配。总之，宏基因组数据的分类学分析可能不适用于检测和量化人类粪便中产雌马酚的微生物。对数据进行功能分析可能提供一种替代方法。然而，要检测少数肠道菌群的基因组成，可能需要比本研究更广泛的测序。
