FIG. 3.

Growth of P. gingivalis hmuR mutant strains in media with hemin (A and D), hemoglobin (B and E), or human serum (C and F) as the heme source. P. gingivalis wild-type strain A7436 and the hmuR site-directed mutant strains were depleted of heme, resuspended in BM, and then inoculated into (A and D) BM supplemented with 1.5 μM hemin, (B and E) BM supplemented with 4 μM hemoglobin, (C and F) BM containing 10% human serum, or BM alone (data not shown). Bacterial growth was monitored by measuring the absorbance at 660 nm of the cultures at the indicated time points. Panels A to C: representative growth of three independent experiments with similar trends. Panels D to F: relative growth of the hmuR mutants compared to that of the wild-type strain. Ratios (y axis) represent the growth (OD value) of P. gingivalis hmuR mutant strains cultured in BM supplemented with different heme sources at different time points compared with that of the wild-type strain, which was arbitrarily set as 1. Data from three independent experiments were expressed as means ± standard deviations and were analyzed by two-way ANOVA. ⧫, A7436, P. gingivalis wild-type strain; ▪, WS1, P. gingivalis hmuR::ermF; ▴, WS21, P. gingivalis hmuR^H95A; •, WS22, P. gingivalis hmuR^H434A; ×, WS23, P. gingivalis hmuR^H95A,H434A; ○, WS24, P. gingivalis hmuR^{YRAP420-423YAAA}; ⋄, WS25, P. gingivalis hmuR^{NPDL442-445NAAA}; □, WS26, P. gingivalis ermF control.