Figure 5.

Transmission electron micrographs of E. coli BL21 expressing the Sha autotransporter [31] immunolabelled with 10-nm-diameter gold particles (A) The negative control, adsorbed serum was used for the primary incubation with E. coli BL21 empty vector and shows very low background of gold particles. (B) Gold-labelling with AT-specific antibodies shows that when Sha is constitutively expressed, proteins are localized on the surface as well as released in the supernatant. So, the protein released can gain access to host cell targets, whereas the protein associated with bacterial cells can mediate agglutination, autoaggregation, and adherence to host cells. Bar 100 nm.