A. Northern blot analysis of the expression of VcdRP and Spot42 sRNA monitored at low cell density (OD600 of 0.1) and high cell density (OD600 of 2.0), in the absence (-) or presence (+) of cAMP (5mM f.c.) supplemented externally in LB medium. The solid triangle indicates the band corresponding to the full-length primary transcript. Probing with 5S rRNA confirmed equal loading. 