Fig. 4

Results from single-cell experiments. A prior warning event increased survival of mother cells, while the warning event had no impact on survival of daughter cells. a The two left bars depict the survival probabilities of the 2000 μg/mL ampicillin stress event of stalked mother cells. The mother cells were either directly exposed to the stress event (green) or had experienced a 10 μg/mL ampicillin warning event (yellow) before the stress event (Fig. 2). The two right bars show the mean survival probabilities of the daughter cells that emerged from divisions of warned (green) or unwarned (yellow) mother cells in the time period between warning and stress event (Fig. 3: light blue dots emerging from cell divisions between warning and stress event). In total 2’369 cells were analyzed (~90 mother and ~60 daughter cells per replicate channel: 8 channels x 2 conditions x ~150 single cells; see Additional file 7: S4). Bars depict the fraction of cells that survived the stress event (means and standard error of the mean based on 8 replicate channels). The interaction of cell type and warning intensity was significant (p < 0.05, see Additional file 7: S5) b We fitted a linear model with the factors cell type (mother cell or daughter cell), warning intensity (0 or 10 μg/mL ampicillin) and cell cycle state (see Additional files 3 and 7: S3 and S5). Combinations of factors ‘cell type’ and ‘warning intensity’ were contrasted. We defined unwarned mother cells as the reference condition (left-most bar equals 0). We then compared the effects of each combination (warned/unwarned and mother/daughter) with each other (multiple comparison testing). The effect size compared to the reference is represented by the height of the bar. Top square brackets (⎴) designate significant effects between two conditions (ANOVA post-hoc test. * p < 0.05, ** p < 0.01, *** p < 0.001). The error bars denote standard errors of the mean. The warning had a significant effect on stress survival for the mother cells (p = 0.001); and warned mother cells survived significantly better than both warned (p = 0.03) and unwarned (p = 0.005) daughter cells. The other conditions were not significantly different from each other. In summary the model established that a warning event had a significant effect on survival of mother cells but no significant impact on survival of daughter cells