Ultrastructural observations showing enteric multiplication ofCystoisospora (Isospora)felis by Endodyogeny

Fine structure of Eimeria (s. I.) vanasi merogony stages in the intestinal mucosa of cichlid fishes

“…Endogenous formation of merozoites within merozoites similar to the process of endodyogeny found in cyst-forming coccidia, such as Sarcocystis, Toxoplasma and Cystoisospora (Scholtyseck 1973, Hilali et al 1979, Ferguson et al 1980), seems to comprise a distinct stage in the sequence of asexual reproductions of Eimeria vanasi. Both intracytoplasmic and epicytoplasmic PVs containing 2 merozoites are frequently observed in LM-studied smears and sections of E. vanasi-infected intestines .…”

Ultrastructural and developmental affinities of piscine coccidia

“…The heteroxenous development demonstrated in some coccidia may serve as further proof of a lower level of specialization, following Landau's (1982) postulation that monoxenous coccidia originated from ancestral heteroxenous forms. Many of the structural features found among piscine coccldia also occur in the heteroxenous cyst-forming coccidla Sarcocystis and Cystoisospora: fragile oocyst; valved sporocysts lacking Stieda bodies which rupture along sutural lines; crystalline bodies in sporozoites and merozoites instead of refractile ones; a PV wall which is either multilayered, or has funnels or invaginations, endodyogeny as a stage in merogonous development and endopolygeny as the main form of merogony (Pelster 1973, Dubey 1977, Ferguson et al 1980. The occurrence of merozoites, dividing by endodyogeny inside migratory macrophages in extraepithelial sites during chronic stage of infection with Eimeria vanasi, recalls a chronic form of Toxoplasma infection (Dubey 1977), and 'cystozoites' of haemogregarines (Kirmse 1979).…”

“…Levinea); Dubey (1977), Ferguson et al (1980)], appears to be the common form of asexual division in successive generations of piscine coccidian merozoites (Fig. 15) prior to their differentiation into meronts (Paperna 1991, Kim & Paperna 1992, Morrison et al 1993a.…”

Ultrastructural aspects ofCystoisospora belli(syn.Isospora belli) in continuous cell lines

“…Merozoites in the initial multiplication stage showed an increase in nuclei and nucleoli and a proliferation of the endoplasmic reticulum and a structure similar to the Golgi complex, which are findings that are typical of the synthesis of DNA, RNA, and proteins (Roberts et al, ; Vetterling et al, ). As observed in C. belli , the ultrastructural studies of the endodyogeny process in T. gondii (Hu et al, ; Nishi et al, ), C. felis (Ferguson et al, ), and Isospora suis (Lindsay et al, ; Matuschka, ) show that during replication, the apical complex of the parent cell remains intact while rhoptries, micronemes, and dense granules are formed individually in the daughter cells. Similar to I. suis (Lindsay et al, 1987), the presence of an intact apical complex in C. belli meronts may be related to the parasites' ability to invade new cells and continue their development in the small intestine.…”

“…A characteristic of the members of the Sarcocystidae family is their ability to multiply asexually by endodyogeny, a process in which two daughter cells are formed inside the mother cell (Ferguson et al, ). Merozoites in the initial multiplication stage showed an increase in nuclei and nucleoli and a proliferation of the endoplasmic reticulum and a structure similar to the Golgi complex, which are findings that are typical of the synthesis of DNA, RNA, and proteins (Roberts et al, ; Vetterling et al, ).…”