Fig. 1: NT formation in exponential and stationary phase.

These images were acquired by fluorescence microscopy; the corresponding phase-contrast images are also shown. For definition of t = 0 refer to Mat & Met. a Exponentially grown wt B. subtilis (LK1432) cells prepared by the GAG method. b Exponentially grown wt B. subtilis (LK1432) cells prepared by the P-GLG method. c One-hundred exponentially growing wt B. subtilis (LK1432) cells bearing NTs were analyzed. Most NTs emanated from the cell poles (75 NTs), followed by NTs from the septal region (16 NTs) and the sides (9 NTs). The positions of NT attachment to the rod-shaped cells were not uniformly distributed over the cell surface (p < 0.001, custom test—see Quantification and statistical analysis). d Stationary phase wt B. subtilis (LK1432) cells prepared by the P-GLG method but to stain the membranes, FM4-64 was used instead of Nile Red, as Nile Red poorly stains membranes of cells from this phase (Supplementary Fig. 2d). e Exponentially grown ΔsigD (LK1873) cells prepared by the P-GLG method. The images were taken at 0 and 15 min time points. White arrows indicate NTs, blue arrows indicate ghost cells in the phase-contrast images. The membrane stain (false colored glow, FM4-64 or Nile Red) is indicated above the images. Scale bar = 5 μm. All experiments (a–e) were conducted in at least three biological replicates with similar results.