title: Acanthamoeba castellanii cysts: new ultrastructural findings.
abstract: During Acanthamoeba castellanii trophozoite-cysts differentiation, four morphological stages were identified by scanning electron microscopy: trophozoite, precyst, immature cysts, and mature cysts. Fluorescence microscopy reveals the presence of small cumulus of actin in the cytoplasm of precysts after treatment with rhodamine phalloidin. By the contrary, in mature cysts, fluorescence was not observed. However, when excystation was induced, large fluorescent patches were present. By transmission electron microscopy, encysting amebas showed small cytoplasmic vesicles containing fibrillar material, surrounded by a narrow area of thin fibrils. Similar appearance was observed in pseudopods and phagocytic invaginations. In addition, large aggregates of rod-shape elements, similar to the chromatoid bodies, described in other amebas, were present in the cytoplasm. These cysts presented large areas with orange fluorescence after treatment with acridine orange.
authors: Department of Infectomics and Molecular Pathogenesis, Center for Research and Advanced Studies, Av. IPN 2508, Zacatenco, 07360, Mexico City, Mexico. bchavez@cinvestav.mx
authors: Bibiana
authors: B
authors: Chávez-Munguía
authors: Lizbeth
authors: L
authors: Salazar-Villatoro
authors: Anel
authors: A
authors: Lagunes-Guillén
authors: Maritza
authors: M
authors: Omaña-Molina
authors: Martha
authors: M
authors: Espinosa-Cantellano
authors: Adolfo
authors: A
authors: Martínez-Palomo
mesh_terms: D048248:Acanthamoeba castellanii / Q000648:ultrastructure*; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D008856:Microscopy, Fluorescence; D033761:Spores, Protozoan / Q000648:ultrastructure*