Fig 6. Overexpression of SoxR in the ΔsufABCDSE mutant.

The E. coli wt (BE1000) and ΔsufABCDSE (AG031) strains carrying the chromosomal PsoxS::lacZ fusion and the pSoxR plasmid or the empty plasmid (pTrc99A) were grown in LB supplemented with IPTG (0.1 mM) until OD₆₀₀ reached 0.2. At time zero (t₀), the cultures were treated with PMS (30 μM), and β-galactosidase activity was assayed at t₀ and after 2 hours (t₂) of growth and expressed as Miller units. The experiments were repeated at least three times. The means and standard deviations are shown. Asterisks represent the statistical significance calculated using the Bonferroni method (** p<0.01; * p<0.05; ns p>0.05).