Ultrastructure ofBlastocystis hominis cysts

Abstract

Blastocystis hominis cysts were concentrated from human faeces by repeated washing in distilled water and centrifugation on Ficoll-Paque. This procedure gave a concentrated suspension of cysts without yielding any non-cystic forms. The cysts were examined by both transmission (TEM) and scanning electron microscopy (SEM). Cysts were surrounded by a fibrillar layer that appeared porous in SEM. Many naked cysts without the fibrillar layer were also visible in SEM. They were variable in shape but mostly circular to oval. The diameter of the cyst without the fibrillar layer was 3.5 microns in both TEM and SEM. The nuclear structure was typical of Blastocystis and exhibited multiple mitochondria with poorly developed cristae. Glycogen was present in small to large clumps in the cytoplasm. The cyst wall was 5-100 nm thick and was bounded internally by an electron-dense plasmalemma.

New Insights on Classification, Identification, and Clinical Relevance of Blastocystis spp

“…The cyst form ( Fig. 1A and 3) is the most recently described form of the parasite, and the late discovery is due to its small size (2 to 5 m), which can result in confusion with fecal debris, and the observation that cysts are infrequently seen in laboratory culture (46,153,154,234,312). The cysts are variable in shape but are mostly ovoid or spherical.…”

“…The cyst is protected by a multilayered cyst wall (Fig. 4), which may or may not be covered by a loose surface coat (153,312,313). The cytoplasm of the cyst may contain one to four nuclei, mitochondria, glycogen deposits, and small vacuoles (5,46,153,312).…”

“…4), which may or may not be covered by a loose surface coat (153,312,313). The cytoplasm of the cyst may contain one to four nuclei, mitochondria, glycogen deposits, and small vacuoles (5,46,153,312). One report (237) described the presence of large multinucleate cysts from the stools of Macaca monkeys, which were 15 m in size, and this was suggested to be an indication of differences among Blastocystis species.…”

Prevalencia de Blastocystis hominis en vendedores ambulantes de comida del municipio Caroní, Estado Bolívar, Venezuela

“…Se trata de un protozoario polimórfico del que se describen cuatro formas principales: forma de cuerpo central o vacuolada, granular, ameboide y el quiste. La primera es la más frecuentemente observada en heces constituyéndose por lo tanto en el estadio diagnóstico (Boreham & Stenzel, 1993;Singh et al, 1995;Zaman et al, 1995;Zierdt et al, 1967). Diversos autores han mostrado que el examen directo de heces es un método prácti -co, barato y eficaz para el diagnóstico de los estadios evolutivos del parásito (Devera et al, 1998a;Pérez-de-Suárez & Guzmán-de-Rondón, 1994;Pires-de-Mato et al, 1998), con excepción del quiste que, debido a su pequeño tamaño, requiere de técnicas especiales (Zaman, 1996).…”

Blastocystis Hominis Infection Pathogenic or Commensal: Short Review

“…20 They are spherical and surrounded by multilayered thick wall. The cyst contain nuclei vary from 1 to 4.…”