Fig. 1.
Analysis of pH, optical density (OD600 nm), and number of colony forming units (CFUs) from cultures of L. acidophilus with or without MS74 cells. To assess the ability of L. acidophilus to maintain a low pH under different culture conditions, L. acidophilus was cultured with or without MS74 cells in the basal medium. The pH measurements were performed 0, 3, 6, 9, 12, and 24 hr after incubation. (A) Measurements of the pH of bacterial suspensions before and after culture, (B) Measurements of the OD600 nm of bacterial suspensions, (C) Measurements of CFUs to assess the viability of L. acidophilus. CFUs are presented as logarithmic values. MS74 cells, immortalized human vaginal epithelial cells; OD600 nm, optical density; CFU, colony forming unit;-○-, MS74 cells alone;-▴-, MS74 cells co-cultured with L. acidophilus;-□-, L. acidophilus alone. Each value represents the mean±SD from 3 independent experiments, with each condition tested in triplicate.