Fig. 1

Effect of deletion of Pp GSK3 on cell division. a Cell division. P. pallidum wild-type, gsk3⁻ and gsk3⁻/GSK3 cells were inoculated at 10⁵ cells/ml in KK2 with autoclaved K. aerogenes and shaken at 22 °C until amoebas had reached late log phase. Cells were then stained with 0.01% DAPI and photographed under phase contrast (Ph, upper panels) and epifluorescence (Fl, lower panels). gsk3⁻ cells were also grown on agar plates with live bacteria and then stained with DAPI (right panels). Bar: 50 µM. b Nuclei per cell. For about 150 cells per strain, the number of nuclei per cell was counted by comparing phase contrast and DAPI fluorescence images, and the fraction of cells with 1, 2, 3 or 4 nuclei was calculated. c Growth in suspension. Wild-type and gsk3⁻ cells were grown in suspension on autoclaved K. aerogenes as described above. At the indicated time points, the cell density was determined and doubling times (T2) were calculated from the exponential phase of the growth curve. Means and SD of 4 experiments are presented. d Growth on agar. Wild-type and gsk3⁻ spores were clonally plated on nutrient agar with live bacteria, and the diameter of emerging plaques in the bacterial lawn was measured with a ruler at 2-day intervals. Means and SD of 4 experiments