Figure 8.

Hysteresis in the PvuII RM system. (A) Summary of the experiment. Two overnight cultures (that did not reach stationary phase) were grown in MOPS-rich medium containing either 0% or 0.1% arabinose. These were then used to inoculate medium containing a range of arabinose concentrations. This experiment was done in triplicate, starting with three different colonies. RNA was then extracted and subjected to reverse transcription QRT-PCR, using kan mRNA levels as the baseline. (B) Relative plasmid DNA copy number. The experiment was carried out as in (A), but samples analysed as in (Figure 6) to determine copy number of the pCC1-based plasmid. Symbols indicate the averages from two experiments, and bars indicate the range. Gray circles indicate cultures diluted from the starter culture lacking arabinose; black squares indicate cultures diluted from the 0.1% arabinose starter culture. (C) Results for the C-protein gene, pvuIIC. The three culture sets inoculated from the 0% arabinose overnights are shown as circles, and the three started from 0.1% overnights shown as squares. The thick orange line in the background shows the results of a mathematical model fit to the data. (D) Results for the REase gene, pvuIIR, otherwise as in (C).