Fig 4. Hda deficiency is suppressed by ArcA overexpression.

A) The hda::cat mutation was introduced into wild-type cells containing plasmid pNDM220 or pNDM-arcA under anaerobic conditions. Cells were restreaked on LB plates with or without the IPTG and incubated aerobically at 32°C for 24 hours. B) Cells were grown exponentially at 32°C in AB medium supplemented with 0.2% glucose and 0.5% casamino acids and treated with rifampicin and cephalexin prior to flow cytometric analysis. When indicated cells were grown with 1mM IPTG. The flow diagram of “hda/pNDM-arcA -IPTG” was obtained from cells grown in presence of 1mM IPTG then washed and regrown in absence of IPTG for 6 hours. Each panel represents a minimum of 30000 cells. The average ori/cell (O/C), ori/mass (O/M) relative to wt/pNDM220 and mass doubling time (τ) are inserted in the histograms. C) The cellular ori/ter ratio determined by qPCR analysis. Shown is the mean ± s.d (n = 3),* = p<0.05.