Fig. 6.
The different phases of V. cholerae wild-type biofilm growth. (A and B) Biofilms in phase I consist of highly ordered N = 1∼6 cells growing along a line, and all cells are bound to the glass substratum. Panel A shows a representative image, and panel B shows the top and side views of the segmented cells in the community. (C and D) Biofilms in phase II consist of N = 20∼100 cells, which form a 2D community with low local order, in which all cells remain in contact with the glass substratum. (E and F) Biofilms in phase III consist of N = 200∼1,000 cells that form a disordered 3D community. Panel E shows the average magnitude of the z-component of the cellular orientation vector <nz>. For the heat map, 26 biofilms with N = 500–600 cells were averaged and the results plotted using cylindrical coordinates with radial coordinate ρ, normalized by the maximum cylindrical radius of the biofilm ρmax. Panel F shows all detected cells in an XZ-slice through a biofilm with N = 510 cells; individual cells are colored according to their value of nz, as indicated in the color bar. (G and H) Biofilms in phase IV are highly ordered 3D communities with N > 2,000 cells. Panel G shows <nz> averaged for 11 biofilms with N = 3,800–4,600 cells, using cylindrical coordinates. Panel H shows the cells in an XZ-slice through a biofilm with N = 3,975 cells; individual cells are colored according to their orientation along the z-direction, nz. Biofilms with cell numbers in between these four growth phases are undergoing transitions from 1D to 2D growth, from 2D to 3D disordered growth, or from 3D disordered to ordered growth, respectively.