2.7.1. Fecal Samples Collection and DNA Extraction
LYSIS
Fecal samples were collected at baseline, at 24 weeks, and at 48 weeks. Participants were provided stool collection kits and instructed to collect an at-home sample within 48 h of their next research visit. The fecal sample was collected using a collection vial and then placed immediately in the home freezer (−20 °C) before being brought to the clinic in a provided cooler bag with a cooler block. Samples received at the research center were immediately placed in a freezer at −80 °C.Genomic DNA was extracted using the ZymoBIOMICS™ 96 MagBead DNA kit (Zymo Research Corp., Irvine, CA, USA) integrating a double lysis (mechanical and chemical) on the Precellys Evolution homogenizer (Bertin Instruments, Montigny-le-Bretonneux, France). DNA extraction was performed on the KingFisher Flex automaton (Thermo Fisher Scientific, Waltham, MA, USA) according to the manufacturer’s instructions. Once obtained, the DNA solutions were assayed by fluorimetry with the Qubit device (Thermo Fisher Scientific, Waltham, MA, USA).