Figure 1

Transcriptional induction of prfA upon acid shock at different time points. Samples were taken before (t = 0) and at five time points until two hours after acid shock. Mean values of fold expression ± standard deviation calculated as ratio between prfA transcription after and before HCl treatment are presented. To obtain a sample of adapted cells, acid-shocked L. monocytogenes (120 min pH 5) were diluted and grown at pH 5.2 to OD_600nm = 0.5. Expression of prfA at 10°C and 18°C was measured by real time qRT-PCR in replicates of three and at 25°C and 37°C in two biologically independent experiments, respectively. The prfA induction was not determined at some time points (e.g., for 10 and 18°C at 15 min, 25 and 37°C at 90 min, and 10 and 18°C for the adaptation sample).