Fig. 3. Signal uptake leads to a shorter communication range in absorbing PlcR-PapR system.

a Normalized YFP expression in signal receivers as a function of their distance to the producers in IPTG-inducible opp system and scoC knockout mutant (right, representative microscopy images). Signal producers in (a) do not express YFP. Gray lines show best fits (see “Methods”). b Communication range decreases for higher IPTG concentrations in the IPTG-inducible opp system ($U=825,p=2.7\times {10}^{-5}$) and decreases even further in the scoC knockout ($U=648,p=1.5\times {10}^{-4}$) (200 μM IPTG, $n=24$; 1000 μM IPTG, $n=43$; scoC, $n=19$; statistics show two-sided Mann–Whitney U tests without adjustments for multiple comparisons). c Representative microscopy images of differently sized clusters of signal producers. d Normalized YFP expression in isolated clusters of signal producers as a function of their half-width (blue dots), observed YFP expression ($n=362$ chambers). YFP levels are normalized to their maximal levels; black line, theoretical prediction based on the measured communication range (see “Methods”); vertical dashed line, the communication range of PlcR-PapR system. Enlarged data points 1–3 correspond to three co-occurring clusters of signal producers visualized in (e). e Observed (dots) and predicted (grid surface) YFP expression in chamber with three co-occurring clusters of signal-producing cells. f Communication range as a function of the cluster size for clusters wider than 3 μm (linear regression: intersect = $14.8\pm 0.5\mathrm{\mu }\mathrm{m}\left(\mathrm{s.e.}\right)$, slope = $-0.04\pm 0.01\mathrm{\mu }\mathrm{m}$, $p=0.0014,n=213$ chambers). Microscopy images: blue bars = region of signal producers; red bars = region of signal receivers; yellow = signal response; scale bar = 10 μM. Source data are provided in Supplementary Data 1.