Fig. 3: DivIC regulates the architecture of the cell wall.

a TEM of SH1000 and ΔdivIC (SJF5450) grown for 2 h with or without IPTG. Scale bars 0.5 μm. b Measurements of peripheral cell wall thickness from TEM images. n = 150 cells per sample, P-values were determined by Mann–Whitney U-tests (****P < 0.0001; ***P < 0.0005). c AFM of the internal and external structures of cell walls from SH1000 and ΔdivIC cells grown for 2 and 3 h in the presence and absence of IPTG. 2 h samples show piecrust development (dotted arrows) at the internal surface (scale bars, 100 nm, Z scales: 76 nm (SH1000), 73 nm (ΔdivIC IPTG), 30 nm (ΔdivIC no IPTG)). 3 h samples highlight internal (scale bars 50 nm, Z scales: 5.4 nm (SH1000), 6.3 nm (ΔdivIC IPTG), 15 nm (ΔdivIC no IPTG)) and external (scale bars 100 nm, Z scales: 40 nm (SH1000), 22 nm (ΔdivIC IPTG), 60.5 nm (ΔdivIC no IPTG)) architectural features (3 h). Arrows show deeper pores. d Cell thickness of single layer cell walls in air. Values were extracted from the AFM images using the 1D height distribution fitting method in Gwyddion. n (left to right) = 50, 40, 48, 40, 50, 23. P-values were determined by unpaired two-tailed t-test with Welch’s corrections (****P < 0.0001; *P < 0.0120).