Tsaii 5 sheep blood

All Sp strains were derived from the unencapsulated D39 strain (D39 Δcps) (Lanie et al., 2007 (link)). Cells were grown in Todd Hewitt broth (Beckton Dickinson) supplemented with 0.5% yeast extract (THY) at 37°C in an atmosphere containing 5% CO₂. Strains were grown on pre-poured tryptic soy agar 5% sheep blood plates (TSAII 5% sheep blood, Beckton Dickinson) with a 5 ml overlay of 1% nutrient broth (NB, Beckton Dickinson) agar containing the required additives or on TSA agar plates containing 5% defribrinated sheep blood (Northeast laboratory). Luria-Bertani (LB) broth and LB agar were used for E. coli. Antibiotic concentrations were used as previously described (Fenton et al., 2016 (link)). All strains, plasmids and oligonucleotides used in this study are provided in the key resources and the supplemental material 1, respectively. The D39 Δcps genotype (Δcps2A’-Δcps2H’) was excluded from derivative strains for clarity. All S. pneumoniae strains used in this study are derivatives of D39 Δcps. Cam = chloramphenicol, Erm = erythromycin, Kan = kanamycin, Spec = spectinomycin, Tet = tetracycline, Amp = ampicillin.

All Sp strains were derived from the unencapsulated strain (D39 Δcps) (Lanie et al., 2007 (link)). Cells were grown in Todd Hewitt (Beckton Dickinson) medium supplemented with 0.5% yeast extract (THY) at 37 °C in an atmosphere containing 5% CO₂ or on pre-poured tryptic soy agar 5% sheep blood plates (TSAII 5% sheep blood, Beckton Dickinson) with a 5 ml overlay of 1% nutrient broth (NB) agar containing the required additives. When required, TSA agar plates containing 5% defibrinated sheep blood (Northeast laboratory) were used. E. coli strains were grown on Luria-Bertani (LB) broth or LB agar. WT Bacillus subtilis strain PY79 (Youngman et al., 1983 (link)) was grown in LB broth or LB agar as described previously (Fenton et al., 2016 (link); Fenton et al., 2018 (link); Flores-Kim et al., 2019 (link)). For both S. pneumoniae and E. coli, antibiotics were used as previously described. A list of strains and plasmids, and oligonucleotides used in this study can be found in the Key Resources Table and in Supplementary file 2, respectively.