Fig. 6.

Transcription of bfpA and perA is repressed during the Cpx response. EPEC strains harbouring bfpA–lux and perA–lux reporters were subcultured in DMEM/F12 as described in Experimental procedures. Normalized luminescence, in units of counts per second (cps) per optical density of the culture (OD₆₀₀) was measured hourly and calculated as described in the Fig. 3 caption. Experiments were performed in quintuplicate at least twice; the mean and standard deviation from one representative experiment are shown. An asterisk (*) denotes significant difference from the wild-type or vector control (P < 0.05, unpaired t-test). A. Comparison of bfpA–lux and perA–lux activity in wild-type strain E2348/69 and cpxA24 mutant ALN195. Results presented are from 4 h post subculture. B. Comparison of bfpA–lux and perA–lux activity in wild-type EPEC harbouring the vector control pCA24N or the overexpression plasmid pCA-nlpE. Strains were subcultured into DMEM/F12 for 2 h, then induced with 0.1 mM IPTG. Results presented are from 5 h post induction.