Entamoeba

Entamoeba coli:
Entamoeba coli is a non-pathogenic amoeba that very closely resembles Entamoeba histolytica
1- The trophozoites of Entamoeba coli range in size from 15-50µm. Their single nucleus contains a large eccentrically located karyosome and coarse and unevenly distributed peripheral chromatin.
The cytoplasm is coarsely granular and often vacuolated. There are a number of food vacuoles which usually contain bacteria.
The trophozoites move sluggishly by short pseudopodia.
2- Precystic stage is very transitory. The cyst of Entamoeba coli measure 10-35µm in diameter. The average diameter is definitely greater than the cysts of the pathogenic amoeba. The cytoplasm granular in appearance. Food vacuoles are not present. Nucleus vary in number from 1-8. The eccentric position of the karryosome can be frequently distinguished even in unstained amoebae. Chromatin bars are thin with pointed ends, peripheral chromatin are coarse and unevenly distributed.