FIG. 1.

Differential expression of hmu genes in the pg1237 mutant (P. gingivalis 1237E) and wild-type 33277 strain. (A) Comparison of the growth curves of P. gingivalis strains. Cells were grown in TSB media. Shown in the curves are the means of four samples, with error bars representing standard errors of the means. One-milliliter aliquots were taken, and the OD₆₀₀ was measured over a period of 70 h. (B) Gene expression in 33277 or in the pg1237 mutant was determined using real time RT-PCR analysis. Change in expression levels was calculated by the ΔΔC_T method, where ΔΔC_T = C_T(33277) − C_T(1237E) and ratio = 2^−ΔΔC_T. The expression levels of the pg1737, fimA, and mfa1 genes were used as controls. Standard errors are indicated (n = 3). Bars with the asterisks are significant (P < 0.05; t test and Bonferroni's test). (C) Differential expression of hmuY and hmuR in P. gingivalis 33277. Expression levels of hmuR and hmuY were determined by using RT-PCR. Lane 1, molecular size standards; lane 2, RT-PCR product of hmuY; lane 3, RT-PCR product of hmuR.