title: Cryptosporidia: epicellular parasites embraced by the host cell membrane.
abstract: The ultrastructure of two gastric cryptosporidia, Cryptosporidium muris from experimentally infected rodents (Mastomys natalensis) and Cryptosporidium sp. 'toad' from naturally infected toads (Duttaphrynus melanostictus), was studied using electron microscopy. Observations presented herein allowed us to map ultrastructural aspects of the cryptosporidian invasion process and the origin of a parasitophorous sac. Invading parasites attach to the host cell, followed by gradual envelopment, with the host's cell membrane folds, eventually forming the parasitophorous sac. Cryptosporidian developmental stages remain epicellular during the entire life cycle. The parasite development is illustrated in detail using high resolution field emission scanning electron microscopy. This provides a new insight into the ultrastructural detail of host-parasite interactions and species-specific differences manifested in frequency of detachment of the parasitophorous sac, radial folds of the parasitophorous sac and stem-formation of the parasitised host cell.
authors.affiliation: Department of Botany and Zoology, Faculty of Science, Masaryk University, Kotlárská 2, 611 37 Brno, Czech Republic.
authors.forename: Andrea
authors.initials: A
authors.lastname: Valigurová
authors.forename: Miloslav
authors.initials: M
authors.lastname: Jirků
authors.forename: Bretislav
authors.initials: B
authors.lastname: Koudela
authors.forename: Milan
authors.initials: M
authors.lastname: Gelnar
authors.forename: David
authors.initials: D
authors.lastname: Modrý
authors.forename: Jan
authors.initials: J
authors.lastname: Slapeta
mesh_terms: D000818:Animals; D001001:Anura / Q000469:parasitology*; D002462:Cell Membrane / Q000469:parasitology* / Q000648:ultrastructure; D003458:Cryptosporidium / Q000254:growth & development / Q000648:ultrastructure*; D005753:Gastric Mucosa / Q000469:parasitology* / Q000648:ultrastructure; D006790:Host-Parasite Interactions / Q000502:physiology*; D008855:Microscopy, Electron, Scanning