Toxic effect of the production of SinI. (A) Growth curves of MDS42-T7 (an McrBC- host) carrying pSin32 with and without IPTG induction. Data are averages of the O.D.540 values of 25 independent colonies each, measured every 5 minutes using the Bioscreen C automated instrument. (B) Mutation rates of uninduced and induced (SinI-expressing) cells. Mutation rates were measured using the cycA fluctuation assay. Error bars represent 95% confidence intervals for the average of 3 independent measurements. ANOVA revealed a significance of p < 0.01. Pairwise t-tests were conducted for the uninduced and induced pairs resulting in a significance of p = 0.077 and p = 0.067, respectively.