title: Electron microscopic observation of the early stages of Cryptosporidium parvum asexual multiplication and development in in vitro axenic culture.
abstract: The stages of Cryptosporidium parvum asexual exogenous development were investigated at high ultra-structural resolution in cell-free culture using transmission electron microscopy (TEM). Early C. parvum trophozoites were ovoid in shape, 1.07 × 1.47 μm(2) in size, and contained a large nucleus and adjacent Golgi complex. Dividing and mature meronts containing four to eight developing merozoites, 2.34 × 2.7 μm(2) in size, were observed within the first 24h of cultivation. An obvious peculiarity was found within the merozoite pellicle, as it was composed of the outer plasma membrane with underlying middle and inner membrane complexes. Further novel findings were vacuolization of the meront's residuum and extension of its outer pellicle, as parasitophorous vacuole-like membranes were also evident. The asexual reproduction of C. parvum was consistent with the developmental pattern of both eimerian coccidia and Arthrogregarinida (formerly Neogregarinida). The unique cell-free development of C. parvum described here, along with the establishment of meronts and merozoite formation, is the first such evidence obtained from in vitro cell-free culture at the ultrastructural level.
authors.affiliation: University of Cologne, Center for Anatomy, Institute I, Joseph-Stelzmann-Street 9, 50937 Cologne, Germany; Department of Parasitology, Faculty of Medicine, Suez Canal University, Ismailia 41522, Egypt.
authors.forename: Hebatalla M
authors.initials: HM
authors.lastname: Aldeyarbi
authors.affiliation: University of Cologne, Medical School, Cologne, Germany; Thousand Talents Plan of the Chinese Government, Center for Biomedicine and Infectious Diseases, Qinghai Academy of Animal Science and Veterinary Medicine, Qinghai University, Xining, China. Electronic address: Panagiotis.Karanis@uk-koeln.de.
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Karanis
mesh_terms: D061245:Axenic Culture; D016785:Cryptosporidium parvum / Q000254:growth & development / Q000502:physiology* / Q000648:ultrastructure*; D046529:Microscopy, Electron, Transmission; D012100:Reproduction, Asexual
keywords: Asexual life cycle; Cryptosporidium parvum; Extracellular development; Host cell-free culture; TEM