Fig. 5.

Cavities in the towers of M. pneumoniae biofilms. Confocal microscopic sections (a–f) of a biofilm of M129 showing cavities within a tower. (a) The biofilm attached to the glass, and (b–f) cross sections of a tower at 6, 9, 14, 18 and 22 µm above the glass surface, respectively. The arrows in (a) point to an area that forms a channel in the bottom section of the tower. The arrows in (b–f) point to voids in the images of selected sections of the towers that represent cavities. (f) A confocal section of the top of the tower; the two arrows indicate where the cavities contact the medium immersing the biofilm. (g–i) A shaded surface rendering of some of the cavities inside the tower formed by M129. (g) Side view of the cavities, and (i) an overhead view. (h) View looking down at the cavities at an angle of 45° above the glass coverslip. (j–l) Cross sections of a biofilm of UAB PO1 at the level of attachment to the glass, and at 14 and 18 µm above the glass, respectively. The white arrows point to void areas in the cross sections that form a continuous cavity that extends from the bottom of the tower to the top of the tower. Bars, 20 µm (a–f, j, k); 10 µm (g–i).