Sporogonic development of the Gregarine Ascogregarina taiwanensis (Lien and Levine) (Apicomplex: Lecudinidae) in its natural host Aedes albopictus (Skuse) (Diptera: Culicidae)

• Published in: The Journal of eukaryotic microbiology 1997-07, Vol.44 (4), p.326-331
• Main Authors: Chen, W.J. (Chang Gung College of Medicine and Technology, Taiwan.), Wu, S.T, Chow, C.Y, Yang, C.H
• Format: Article
• Language: English
• Subjects: AEDES ALBOPICTUS; Apical complex; Ascogregarina taiwanensis; Biological and medical sciences; Culicidae; Fundamental and applied biological sciences. Psychology; Life cycle. Host-agent relationship. Pathogenesis; mosquito; oocyst; Protozoa; SPOROZOA; sporozoite; ultrastructure
• ISSN: 1066-5234; 1550-7408
• DOI: 10.1111/j.1550-7408.1997.tb05674.x

Sexual reproduction of Ascogregarina taiwanensis occurred in pupal Malpighian tubules of its natural host Aedes albopictus, resulting in the formation of gametocysts within which oocysts developed. Sporogony proceeded in each newly formed unsporulated oocyst; eight sporozoites were formed after completion of nuclear divisions followed by the cytokinesis. Developing oocysts were separated by gradient centrifugation on percoll based on different buoyant densities. The slender sporozoite had a typical apical complex composed of a coiled conoid, polar rings, rhoptries with ductules, subpellicular microtubules and micronemes. An apical cavity was seen in the gland‐like rhoptries. Mitochondria of gregarines were not seen in any stage during the sporogony. Howeever, amylopectin granules were frequently seen in the cytoplasm. These starch‐related granules became scant when the sporozoite was formed. We assumed they were associated with the energy source. Since the apical complex was only present in the sporozoite stage, it was most likely related to the invasion of host epithelial cells of the midgut during the early phase of infection.