Avinyl anaerobic chamber

A list of bacterial strains used in this work can be found in the
Key Resources Table and Table S4.
Escherichia coli S17–1 λ
pir was grown aerobically in Lysogeny Broth (LB; 10 g/L
tryptone, 5 g/L yeast extract, 5 g/L NaCl) at 37°C under agitation.
Bacteroides strains were cultured anaerobically in a
vinyl anaerobic chamber using 70% N₂, 20% CO₂, and 10%
H₂ gas mixture (Coy Laboratory Products, Grass Lake, MI). All
Bacteroides cultures were grown on Difco Brain Heart
Infusion (BHI) agar supplemented with 10% defibrinated horse blood (BHI-HB;
Quad Five, Ryegate, MT), or in tryptone-yeast extract-glucose broth (TYG; 10
g/L tryptone, 5 g/L yeast extract, 2 g/L glucose, 500 mg/L cysteine free
base, 100 mM pH 7.2 potassium phosphate, 20 mg/L MgSO₄ ∙
7H₂O, 400 mg/L NaHCO₃, 80 mg/L NaCl, 100 mg/L
resazurin, 0.0008% CaCl₂, 0.4 μg/L FeSO₄,1
μg/L menadione, 0.2 mM histidine, 1.9 μM hematin) at
37°C. When necessary, ampicillin (100 μg/mL), gentamicin (200
μg/mL), erythromycin (25 μg/mL), 5′-flourodeoxyuridine
(FUdR; 20 μg/mL), or tetracycline (2 μg/mL) were supplemented
in the media.