Ultrastructure and development of Microsporidium ovoideum (Thélohan, 1895) Sprague, 1977, a microspohdian parasite of the red band fish ( Cepola macrophthalma L) : Redescription of the organism and reassignment to the genus Microgemma, ralphs & matthews 1986

Abstract

Summary A study of the ultrastructure and life cycle of Microsporidium ovoideum , a hepatic parasite of Cepola macrophthalma , has been carried out. This parasite caused xenomas up to 1–2 mm, which consisted of a hypertrophic cell, filled with different stages of the parasite and rests of the host cell organelles, which had a pychnotic hypertrophic nucleus. Merogonic stages consisted of round multinucleate plasmodia that divided by plasmotomy or exogenous budding, and were not enclosed by any membrane. Sporogonic plasmodia divided by exogenous budding to produce sporoblast mother cells which after a binary fission become sporoblasts. Sporogony occurs in direct contact with host cytoplasm. The spores, which are ovoid and uninucleate, show a posterior vacuole in the posterior third of the spore and an isofilar polar filament with 6–8 coils. The characteristic features permit a reassignation of this microsporidium into the genus Microgemma and give a new combination: Microgemma ovoidea .