Temporal transcription of sigH. Growth of RV2002 has been monitored by OD600 (right axis). Time is indicated in hours relative to the approximate transition to stationary phase (T). mRNAs levels of ldh (grey blocks) or sigH (white blocks) were measured by qPCR and expressed as fold change relative to an early-exponential calibrator sample (left axis). For sigH, results have been further normalized by ldh mRNA levels and expressed as sigH/ldh ratio. Error bars represent standard deviation. A fold change of 1 indicates a constant level of transcripts.