Protistology 1 (1) 34–42 (1999)
Light and electron microscopic observations on life cycle stages of Adelina grylli Butaeva 1996
(Sporozoa, Adeleidae) from the fat body of the cricket Gryllus bimaculatus
Yulia Ya. Sokolova, Fatima G. Butaeva and Viacheslav V. Dolgikh
Laboratory of Microbiological Control, All-Russian Institute for Plant Protection, St. Petersburg, Russia
Summary
Adelina grylli Butaeva, 1996 (Sporozoa, Adeleina) was described from crickets Grillus bimaculatus from Middle Asia (Ashhabad).
The parasite infected the laboratory population of Gryllus bimaculatus. Zoites, dividing schizonts, macrogamonts, microgamonts and
oocysts are studied in light and electron microscopes (EM). The infective stage is a sporulated oocyst with 4 - 20 sporocysts, each containing 2
sporozoites. Sporozoites, like other generations of zoites, display ultrastructure typical for the coccidian motile stages with apical complex, pellicle,
micronemes and subpellicular microtubules. Sporozoites penetrate through the intestinal epithelium inside the fat body cells, the primary infection
site. There they are enveloped in a parasitophorous vacuole (PV) that often contains inclusions derived from both the host cell and the parasite.
The growing parasite loses its apical organelles to convert into meront. Meronts undertake schizogony with the formation of bundles of
merozoites. Merozoites of the second generation give rise to meronts, macrogamonts or microgamonts. A tubular-like secretory material
resembling the tubular network of Toxoplasma PV is discovered inside the PV containing microgamonts of A. grylli. Micro- and
macrogamonts are associated in a syzygy. The zygote contains abundant amylopectin and numerous protein granules and vacuoles. The host
haemocytes are involved in the oocyst wall formation. Cellular response to the infection with Adelina grylli: proliferation of haemocytes,
melanization, infiltration of the infected tissue with haemocytes, is very prominent, especially on sporogony stages of parasite development. Only
3 adeleid coccidian species have been so far studied in EM. The present study provides new data on the ultrastructure of life cycle stages of
Adelina grylli, aimed to additional diagnostic criteria for Adelina species.
Key words: Coccidia, Adeleidae, Adelina grylli, Gryllus bimaculatus, ultrastructure
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