Cultivation of Streptococcus ferus and E. coli

Bacterial strains and plasmids used in this study are listed in Table S1. S. ferus strains were derived from DSM20646 (37 (link)) were grown on Todd-Hewitt plates (TH, BD Biosciences) with 1.4% Bacto-Agar (BD Biosciences) and 0.2% yeast extract (VWR), in Todd-Hewitt broth with 0.2% yeast (THY), or in a chemically-defined medium (CDM) containing 1% glucose at 37°C with 5% CO₂. The components and recipe for CDM used were as described previously (38 (link)). E. coli strains were grown on Luria-Bertani (BD Biosciences) plates with 1.4% Bacto-Agar at 37°C or in Luria-Bertani (LB) broth with shaking at 175 rpm. When required spectinomycin (50–100 μg/mL), erythromycin (0.5 μg/mL for S. ferus, 500 μg/mL for E. coli), or kanamycin (50–100 μg/mL) were added to S. ferus or E. coli culture media.