FIG 6.

Growth curves of cariogenic and commensal Streptococcus species. Bacteria were grown aerobically at 37°C in liquid M9 medium supplemented with 100 mM glucose, 1 μM FeCl₃, either with or without 100 μM enterobactin purified from R. mucilaginosa, and with or without 8 μg/ml catalase. Growth curves in black represent cultures amended with enterobactin. Statistically significant growth curves (P < 0.05) are shown with corresponding P values. Error bars reflect the standard error of the mean (calculated from triplicates). n.s., not significant. (A) Growth of cariogenic S. mutans strain B04Sm5 with enterobactin only (left panel) and with enterobactin and catalase (right panel). (B) Growth of cariogenic S. mutans strain UA159 with enterobactin only (left panel) and with enterobactin and catalase (right panel). (C) Growth of commensal S. sanguinis ATCC 49296 with enterobactin only (left panel) and with enterobactin and catalase (right panel). (D) Growth of S. gordonii ATCC 35101 with enterobactin only (left panel) and with enterobactin and catalase (right panel). (E) S. salivarius strain SHI-3 with enterobactin only (left panel) and with enterobactin and catalase (right panel). (F) Growth of S. oralis ATCC 35037 with enterobactin only (left panel) and with enterobactin and catalase (right panel). Graphs were generated and statistically validated using R Studio and the “statmod” and “ggplot2” packages (48–50).