The organization of the wall filaments and characterization of the matrix structures of Toxoplasma gondii cyst form

Cell Microbiol. 2011 Sep 8. doi: 10.1111/j.1462-5822.2011.01681.x. [Epub ahead of print]

The organization of the wall filaments and characterization of the matrix structures of Toxoplasma gondii cyst form

Lemgruber L, Lupetti P, Martins-Duarte ES, De Souza W, Vommaro RC

SourceLaboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil. Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagens, Rio de Janeiro, Brazil. Parasitology - Department of Infectious Diseases, University of Heidelberg Medical School, Heidelberg, Germany. Department of Evolutionary Biology, University of Siena, Siena, Italy. Instituto Nacional de Metrologia e Qualidade Industrial - Inmetro, Rio de Janeiro, Brazil.

Abstract
The encystation process is a key step in Toxoplasma gondii life cycle, allowing the parasite to escape from the host immune system and the transmission among the hosts. A detailed characterization of the formation and structure of the cyst stage is essential for a better knowledge of toxoplasmosis. Here we isolated cysts from mice brains and analysed the cyst wall structure and cyst matrix organization using different electron microscopy techniques. Images obtained showed that the cyst wall presented a filamentous aspect, with circular openings on its surface. The filaments were organized in two layers: a compact one, facing the exterior of the whole cyst and a more loosen one, facing the matrix. Within the cyst wall, we observed tubules and a large number of vesicles. The cyst matrix presented vesicles of different sizes and tubules, which were organized in a network connecting the bradyzoites to each other and to the cyst wall. Large vesicles, with a granular material in their lumen of glycidic nature were observed. Similar vesicles were also found associated with the posterior pole of the bradyzoites and in proximity to the cyst wall.

© 2011 Blackwell Publishing Ltd.

PMID:21899696[PubMed - as supplied by publisher]