Relative <i>pmpD</i> transcription in prototype and clinical isolate strains of <i>C. trachomatis</i> serovar L2 (A), D (B), and A (C).

<p>Total RNA was isolated from <i>Chlamydia</i> infected McCoy cells at 2 (L2), 4, 6 (L2), 8, 12, 24, 30 (A), 36, 48, 54 (A), 60 (D), and 72 (D) h p.i., and from purified EBs, random primed, and assayed by real-time RT-PCR for 16S rRNA and <i>pmpD</i> copy numbers. Relative <i>pmpD</i> expression at each time point was calculated by dividing the average <i>pmpD</i> copy number by the average 16S RNA copy number at the same time point and multiplying by 1×10⁶<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0005191#pone.0005191-Hogan1" target="_blank">[29]</a>. Error bars were based on the standard error of the mean <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0005191#pone.0005191-Hogan1" target="_blank">[29]</a>. Note that serovar A <i>pmpD</i> expression levels are much higher than levels in serovars D and L2.