FIG. 4.

Expression of the hbhA gene in the lung and spleen tissues of mice aerogenically challenged with the virulent M. tuberculosis Erdman strain as determined by real-time RT-PCR. ftsZ-normalized (A) and 16S rRNA-normalized (B) levels of hbhA were determined at the time points shown in Fig. 3. Five mice per time point were sacrificed, and RT-PCR was carried out four times on each sample. Error bars show standard deviations. Comparisons were performed by using the two-tailed Student t test. Asterisks indicate statistically significant differences (P < 0.05).