Extended Data Fig. 5: Cys and Cys-containing molecules in MRS exist primarily as mixed disulfides and addition of chemical reducing agents permits L. iners growth.
a, Growth of L. iners and L. crispatus at 28 hours in MRSQ broth supplemented as indicated with the reduced thiols L-Cys, D-Cys (the non-physiological enantiomer of L-Cys), GSH, or homocysteine (each 4 mM), with their oxidized counterparts L-cystine, D-cystine, oxidized glutathione (GSSG), or homocystine (each 2 mM), or with the non-sulfur-containing reducing agent Tris(2-carboxyethyl)phosphine (TCEP; 4 mM), H2O2 (0.4 mM), or L-cystine + H2O2. b, Concentrations of reduced Cys (baseline median concentration 1.11 μM) and glutathione (GSH; baseline median concentration 1.70 μM) in MRSQ broth supplemented with the oxidizing agent H2O2 (0.4 mM), the reducing agents TCEP or homocysteine (each 4 mM), or homocysteine’s oxidized counterpart homocystine (2 mM). c, Growth at 7 days of L. crispatus and L. iners in HMRS broth with 1.1 mM L-Gln (“HMRSQ”) supplemented as indicated with L-Cys, L-cystine, TCEP, homocysteine, or homocystine at the above concentrations. All plots depict median ± range for 3 replicates per condition and each plot is representative of 1 of ≥2 independent experiments per strain and media condition. Bar coloring highlights the pairing of media conditions with each thiol-containing reducing agent and its oxidized counterpart.
