Figure 2: Localisation of V. cholerae in A. castellanii with a magnification of 3700x. A. alone cultivated A. castellanii trophozoite as negative control, characterized by nucleus, vacuoles and pseudopodia. B. Many empty vacuoles, pseudopodia and more than 50 cells of V. cholerae O139 inside A. castellanii trophozoite on day 6 of co-cultivation. C. More than 40 cells of V. cholerae O139 inside A. castellanii cyst characterized by double wall called ecto-and endocyst, on day 7 of co-cultivation.