[Microcultures of Entamoeba]

The purpose of this study was the development of a microculture system for Entamoeba using ultrathin culture chambers, characterized by constant culture conditions, where the growing amebas can constantly be observed under the microscope, and which allows rapid variations in the characteristics of the culture medium, so as to determine the optimal conditions for growth and encystment of the ameba. After a lag phase the number of amebas increased following exponential kinetics. The E. invadens distribution in the culture chamber continued up to a total surface of (444 mm2) with in 7 days. On the whole E. invadens showed a tendency of not forming aggregates and growing until a confluent monolayer was reached. On the other hand, E. histolytica grew faster, covering the internal surface of the chamber in 5 days, and its growth went beyond a monolayer, since it covered all the internal walls, forming multiple aggregates. Encystment was induced in E. invadens by changing the feeding medium in the chamber for encystment medium. The encystment we observed was lower than that previously reported.