Figure 2.

T4SS-associated extracellular densities

(A) Slices through electron cryotomograms of C. burnetii cells indicating the presence of T4SS particles without any extracellular densities associated with them.

(B) Slices through electron cryotomograms of C. burnetii cells showing the presence of unstructured extracellular densities above the T4SS particles.

(C) Slices through electron cryotomograms of C. burnetii cells illustrating different types of extracellular densities associated with T4SS such as: short filament-like density (black arrow), crown-like density (yellow arrows), tubular densities (orange arrows). Green arrow point to tubular densities where no T4SS could be identified at their bases. Scale bar is 20 nm. OM = outer membrane, IM = inner membrane.