FIG. 2.

Comparison of growth curves and cspA1/A2 mRNA content between a pnp mutant (Y. enterocolitica YM 205) (A and B) and its parental strain (Y. enterocolitica W 22703) (C and D) following a cold shock from 30 to 5°C. dt, doubling time. The lag periods after the cold shock (A and C) are indicated by open symbols; restart of exponential growth is indicated by filled symbols. The Northern blots (B and D) were obtained with a probe specific for cspA1 and show a lower monocistronic and an upper bicistronic signal of the cspA1/A2 tandem. In addition, the blot of the pnp mutant shows a band below the 310-base (b) marker band, which is probably a degradation product. The CTs are obtained from samples without cold shock. The locations of markers are shown by arrows, and their lengths are indicated. O.D., optical density.