Figure 1.

cspA mRNA steady state level following growth resumption at 37°C. An overnight culture of E. coli MRE600 grown at 37°C in M9 medium was diluted (1:100) in parallel with LB (●) or with M9 (▴) fresh medium and cell aliquots were harvested for RNA extraction at the indicated time after resumption from stationary phase. About 6 μg of total RNA were subjected to Northern analysis. The cellular level of cspA transcripts were evaluated by imager quantification of the radioactivity associated with the mRNA and expressed as Arbitrary Units (AU). Data represent the average of at least two independent experiments and standard deviation is indicated. The profile of Colony Forming Units (CFU) during growth in rich (LB,○) or minimal (M9, Δ) medium as a function of time after nutritional up-shift is also reported. Further details are provided in Materials and Methods.