The fine structure of the Acanthamoeba polyphaga cyst wall

摘要: Members of the genus Acanthamoeba are present in diverse environments, from freshwater to soil, and also humans, causing serious brain corneal infections. Their life cycle presents two stages: dividing trophozoite quiescent cyst. The structures these stages have been studied for many years, structural data used taxonomy. ultrastructural work on cysts was carried out previously by routine transmission electron microscopy (TEM), a process that requires use chemical fixation, procedure can cause artifacts ultrastructure material. In order prevent fixation artifacts, we processed polyphaga ultrarapid freezing, followed freeze-fracturing deep-etching, obtain 3D visualization arrangements cyst wall. exocyst presented an irregular surface, with vesicles located within or near this layer. endocyst, instead, showed biphasic arrangement more compact district its innermost part, loosened outer For reason, it difficult distinguish filaments intercyst space those forming endocyst. Surprisingly, thinner when compared samples conventional TEM, evidencing possible damage consequent fixation.