Fig. 3 | Nature Communications

Fig. 3

From: Shaping bacterial population behavior through computer-interfaced control of individual cells

Fig. 3

Specifying gene expression distributions in small bacterial populations using iCL control. a CFP intensity trajectories (gray lines) for individual Escherichia coli cells tracking targets (red lines) under model-based control in either OL (left panel, n = 55 cells) or iCL mode (right panel, n = 49 cells), pooled from two replicate experiments. Deviations of average population trajectories (blue lines) from targets represent errors in control of the mean. Expression distribution breadths (shaded regions, ±1 s.d.) indicate errors in controlling individual cells. iCL control reduces mean error and cell-to-cell variation, and removes extended excursions in responsiveness seen with OL control (e.g., asterisk-labeled CFP trajectory, Supplementary Movie 3). b Individual CFP trajectories (purple, teal lines) and mean trajectories ±1 s.d. (blue lines and purple, teal-shaded regions, 1 h moving average) for subsets of cells controlled with targets (red lines) of 10 a.u. or 20 a.u. (n = 18, 14 cells, respectively). All cells switch from OL (orange-labeled time interval) to iCL (blue interval) control at 780 min. Individual light stimulation sequences (green: activation, red: repression) for cells targeted to 20 a.u. (upper sequences) and 10 a.u. (lower sequences) are displayed below the plot. Distributions of CFP levels in OL and iCL regimes (during gray shaded intervals) are shown to the right. iCL control (right plot), resolves cells into target group distributions (purple, teal distributions, smoothed: dashed lines) by reducing large errors between target group means (triangles) and expression targets (red lines), and narrowing individual errors (error bars: ±1 s.d.). c Average power spectral densities of OL- and iCL-controlled (orange, blue) fluorescence trajectories (in gray shaded intervals) in b. iCL control reduces fluctuations at frequencies below 0.02 min 1. Average power spectral estimates are for 14 mean-subtracted trajectories with constant fluorescence target of 20 a.u. (spectra are similar for 18 cells targeting 10 a.u.). Dashed lines denote standard error of the mean. d Single-cell temporal patterning of CFP expression in 24 cells over 24 h. iCL control targets are rasters of a binarized image (inset) with fluorescence levels 0 and 15 a.u. Cells shown are automatically selected by longest-validity (Methods) from eight simultaneous replicates

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