Temporal changes in population distribution and cell growth. (a) Cell growth. Temporal changes in cell concentration were examined at 2-h intervals (0–14 h; extension till 22 or 30 h in slow growth conditions). Closed and opened symbols represent the cell populations born from the green and red initial states, respectively. Circles, squares, and triangles indicate growth in the presence of both amino acids and with single addition of leucine or histidine, respectively. (b) Temporal changes in the distribution of relative fluorescence intensity. Cells preliminarily grown in the presence or absence of IPTG were approximately inoculated 106 cells/mL into fresh media containing 5 μM IPTG under different nutritional conditions. Timed sampling of the cell culture was performed at 2-h intervals (except from 14 to 22 h). Cell concentration and expression level were measured by flow cytometry. The distributions of newly formed populations (from 0 to 30 h or 22 h) are shown from light to dark grey, respectively. Population propagation with the addition of both amino acids or with the single addition of 1 mM leucine or 1 mM histidine are shown in the left, middle and right panels, respectively. (c) Relationship between growth and expression. The growth recovery trajectory is indicated with respect to the temporal changes in distribution shown in (a) and (b). Circles filled in red indicate the 0 h time point.
