Figure 7
Iron-triggered prophage activation is dependent on the cellular SOS response. (A) Time lapse studies of a ΔdtxR strain containing the genomically integrated prophage reporter Plys-eyfp (strain: C. glutamicum ΔdtxR::Plys-eyfp). Cells were grown in a microfluidic chip device (see material and methods) in CGXII minimal medium with 2% (w/v) glucose and under a constant flow rate of 300 nl min−1. (B) C. glutamicum wild type, ΔdtxR and ΔrecA strains, containing the integrated Plys-eyfp reporter, were cultivated under iron up-shift conditions (1 → 36 µM FeSO4). After 4 h samples were taken and analyzed by flow cytometry. Whereas a prophage-induced subpopulation is clearly visible in Wt and ΔdtxR cells (1.28% and 4.61%, respectively), almost no activity of the phage reporter was observed in ΔrecA cells. Deletion of dtxR and recA was complemented by transforming the respective strains with the plasmids pAN6-dtxR or pAN6-recA, respectively. Shown are representative scatter plots from three biological replicates; absolute values varied between replicates whereas the overall trend was consistent.
