Electron microscopy of Acanthamoeba sp. (A) Transmission electron microscopy of a trophozoite. (B) Scanning electron microscopy of a cyst. (C) Transmission electron microscopy of a cyst. Ec, ectocyst; En, endocyst; M, mitochondria; N, nucleus; Op, operculum; Os, ostiole. Scale bars = 2 μm.