Fig. 2: Timing of holdfast synthesis after surface contact in WT and flagellar mutant populations.

(A) Schematic representation of timing of holdfast production by surface-contact stimulation or by developmental program. t₀ = time when the cell first encounters the surface, in the case of surface stimulated holdfast production or time of cell division, in the case of developmentally regulated holdfast production; t_H = time when holdfast is first detected on the cell by fluorescence microscopy. Holdfast synthesis timing is calculated from t_H – t₀. (B) Representative time-lapse images of a single NA1000 hfsA⁺ WT cell reaching the surface (phase channel) and producing a holdfast, visualized using AF488-WGA binding (fluorescence channel). (C) Timing of holdfast synthesis after surface contact on a glass surface in liquid compared to holdfast synthesis after division. Experimental data points for NA1000 hfsA⁺ WT and Mot^- strains were extracted from (Ellison et al., 2017). Data are represented by box plots with 5–95% percentile whiskers, from 2 independent replicates. Statistical comparisons are calculated using Mann-Whitney unpaired t-tests. **** P < 0.0001; ns = not significant. The number of cells plotted (cells which arrived on the surface without a holdfast and produced one within 3 h) is n = 115, 156 and 182 for WT, ∆flgE and ∆motB respectively. The total number of cells tracked (including cells arriving with holdfast already synthesized) is n = 241, 257 and 566 for WT, ∆flgE and ∆motB respectively.