FIG. 9.

Cytopathic activity of E. histolytica HK-9 axenically and monoxenically cultivated with E. coli (Ec) O55 or 346 for several months. The destruction of the BHK cell monolayer by E. histolytica trophozoites was evaluated as described in Materials and Methods. The data are expressed as percentages of the cytopathic activity control values (axenic HK-9). Each point is an average of three determinations. The bars indicate standard errors.