Figure 1—figure supplement 1. | A long-term epigenetic memory switch controls bacterial virulence bimodality

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A long-term epigenetic memory switch controls bacterial virulence bimodality

Figure 1—figure supplement 1.

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The Hebrew University of Jerusalem, Israel
Figure 1—figure supplement 1.
Download figureOpen in new tabFigure 1—figure supplement 1. EPEC growth on LB measured by ScanLag and time-lapse microscopy.

Static cultures of EPEC were grown in DMEM for 3 hr at 37°C to OD600 ~0.3 (activating conditions). Cultures were then diluted, plated on LB agar, and incubated at 32°C (non-activating conditions). (AC) Growth of colonies was monitored at 15 min intervals using the ScanLag system. (A) Histogram of the fraction of colonies detected at each time point. (B) Histogram of colony area growth time, i.e. the time taken to increase the colony area from 20 to 80 pixels. (C) Two-dimensional histogram of the data in (A) and (B) allows the visualization of the bimodal phenotype. Note the diagonal shift of the SMALL morphotype suggesting an increase in time to reach the given area and not an increased lag duration (Levin-Reisman et al., 2010) (n = 1184). (AC) Experiments were repeated in at least four independent biological replicates. (D) Analysis of single-cell generation time by time-lapse phase microscopy. Bacteria from BIG and SMALL colonies were suspended in LB and were placed on LB agar pads and observed by microscopy. Data are presented as the median ± Median Absolute Deviation (MAD) of each morphotype. The p-value was calculated by Wilcoxon rank sum test, h = 1. (2% of non-dividing cells were excluded from the analysis since their division was out of the observed time range). Similar results were obtained in two independent biological repeats.

DOI: http://dx.doi.org/10.7554/eLife.19599.005