Anaerobic Culture of Bacteroides thetaiotaomicron

Bacterial strains and primers used in this study are listed in Table S3B. B. thetaiotaomicron was grown in a flexible anaerobic chamber (Coy Laboratory Products), filled with 70% N₂, 20% CO₂, and 10% H₂. The culture medium for B. thetaiotaomicron was a defined minimal medium (28 (link)), supplemented with 500 μM d,l-methionine instead of vitamin B₁₂, unless otherwise noted. E. coli was grown aerobically at 37°C at 225 rpm in Luria-Bertani broth. Antibiotics were supplemented as needed at the following concentrations: ampicillin, 100 μg/mL; gentamicin, 200 μg/mL; erythromycin, 25 μg/mL; tetracycline, 2 μg/mL; and 5-fluoro-2′-deoxyuridine (FUdR), 200 μg/mL.