Human gut microbiota sequencing: GM139
DNA was extracted using QIAamp Powerfecal pro DNA kit (Qiagen, Germany) as per manufacturer instructions, and quantified via Qubit (Thermo Fisher Scientific). The sequencing of the V3V4 hypervariable regions of the bacterial 16S rRNA gene was performed in service  by Macrogen (Seoul, Republic of Korea), according to the Illumina 16S Metagenomic Sequencing (Illumina, USA).