Bhi medium

Veillonella parvula SKV38 was used as the wild-type strain for our experiments. We also used V.parvula DSM2008, V. dispar LD205, V. atypica RJX1392, V. atypica RJX1514, and V. ratti 84 (Supplementary Table 1). Cells were grown routinely in SK agar (composition in g/L: yeast extract 10, casitone 10, Na₂HPO₄ 0.4, NaCl 2.0) supplemented or not with DL-lactate (25 mM) and/or potassium nitrate (20 mM) unless otherwise indicated. The media with both lactate and nitrate added we called SKLN. Cells were incubated for 24 h under anaerobic conditions at 37°C. The growth of SKV38 was also assessed in GIFU anaerobic medium (HiMedia, Cat# M1801), Difco^™ Reinforced Clostridium medium (BD Cat# 218081), DifcoTM Columbia broth (BD, Cat# 294420), MRS broth (Sigma, Cat# 69966), and BHI medium (HiMedia Cat# M210). Antibiotics were added to the medium when appropriate: 5 μg ml⁻¹ tetracycline, 5 μg ml⁻¹ chloramphenicol, 20 μg ml⁻¹ erythromycin for V. parvula, and 100 μg ml⁻¹ ampicillin and 100 μg ml⁻¹ spectinomycin for E. coli. X-Gal (5-bromo-4-chloro-3-indolyl-β-D-galactopyranoside) was dissolved in DMSO (40 mg/ml), and added to plates for white/blue selection at a final concentration of 0.1 mg/ml.