Skip to main content
. 2020 Mar 5;11:1203. doi: 10.1038/s41467-020-15017-1

Fig. 2. The phenotypic heterogeneity at the colony level.

Fig. 2

L. lactis colonies grown for 48 h on CDM-agar plates with either, a, low (0.025 mM) or, b high (1 mM) methionine concentrations. a, b left image shows green-fluorescence channel and right image shows bright-field channel. Scale bars, 1 mm. c Mean fluorescence intensities of individual colonies grown on CDM-agar plates at different methionine concentrations (0.025–0 mM, red to blue; see also Supplementary Figs. 2, 3). Transparent boxes show mean and standard deviation, and number between parentheses shows number of analyzed colonies. d Distribution of mean fluorescence intensities across colonies for different methionine concentrations (0.025–10 mM, red to blue). Vertical dotted line demarcates colonies categorized as having low met expression (GFP−) or high met expression (GFP+). Scale bar, 1 mm, e Fraction of GFP+ colonies at different methionine concentrations. Dotted line shows fit of step function (y = a-a/(1 + e−100·(x+b)); a = 0.450 ± 0.007 (s.e.), Pa < 10−10, b = 3.110 ± 0.001, Pb < 10−16). f Fluorescence measurements by flow cytometry show the met expression in each type of colony phenotype: GFP+ colony (light-red) grown on low methionine concentrations (0.025 mM), GFP− colony (dark-red) grown on low methionine concentrations (0.025 mM), and GFP− colony (blue) grown on high methionine concentrations (10 mM). 10,000 ungated events for each sample are shown. g Switching rate at different methionine concentrations (0.025 mM to 10 mM, red to blue). Inset shows example of colony with switch in expression level. Numbers in parenthesis show number of colonies with expression switch and total number of analyzed colonies. Dotted line shows exponential fit (y = e−a·(x–b); a = 1.34 ± 0.27 (s.e.), Pa < 0.01; b = 6.41 ± 0.61, Pb < 10−5). Scale bar, 1 mm. Source data are provided as a Source Data file.