Chlamydia glycolytic enzymes are downregulated during development. The relative gene expression of a subset of C. trachomatis glycolytic enzymes (glucose-6-phosphate isomerase, pgi; aldolase A, dhnA; pyruvate kinase, pykF) at 12, 24, 36, and 48 h postinfection of HeLa cells was determined by RT-qPCR. Gene expression was normalized to 16S rRNA levels and the expression at 8 h postinfection (dotted line). The late-expressed gene encoding the outer membrane protein OmcA (omcA) was included as a control. The y axis is a log scale. The data show the means and the SD of a combination of three independent experiments. *, P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001 (Student t test).