Figure 4.

Yersinia pseudotuberculosis can survive up to 1 week within A. castellanii cysts. (A) Entry into trophozoites and survival of bacteria in cysts after pre-culture at 37 or 25°C. Error bars indicate mean ± SD of at least three independent biological replicates. ** = P < 0.001. EC = E. coli DH5α, YPT = Y. pseudotuberculosis IP32953. (B) Transmission electron micrographs of Y. pseudotuberculosis IP32953 localized within an A. castellanii cyst. (C) An uninfected A. castellanii cyst. L = lipid droplet, Yp = extracellular Y. pseudotuberculosis, Ypi = intracellular Y. pseudotuberculosis, Ed = endocyst wall, Ex = exocyst wall. Scale bar representing 2 μm is indicated.