title: Early developmental stages of a protozoan parasite, Marteilioides chungmuensis (Paramyxea), the causative agent of the ovary enlargement disease in the Pacific oyster, Crassostrea gigas.
abstract: A paramyxea, Marteilioides chungmuensis, causes the irregular enlargement of the ovary in the Pacific oyster, Crassostrea gigas in Korea and Japan. The knowledge about the life cycle of the parasite has been limited to the sporulation stages within the oocyte of oysters. In this study, we used the parasite-specific DNA probes and electron microscopy to experimentally infected oysters in a field and successfully clarified early developmental stages of the parasite. The parasite invaded the oysters through the epithelial tissues of the gills, mantle and labial palps. Extrasporogony repeatedly occurred in the connective tissues by binary fusion. The inner cell of the extrasporogonic stage migrated into the gonadal epithelium, invaded the oocyte to start sporulation.
authors.affiliation: Laboratory of Fish Diseases, Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1, Yayoi, Bunkyo Tokyo 113-8657, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Itoh
authors.forename: Hideki
authors.initials: H
authors.lastname: Komiyama
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Ueki
authors.forename: Kazuo
authors.initials: K
authors.lastname: Ogawa
mesh_terms: D000818:Animals; D005260:Female; D006790:Host-Parasite Interactions; D008018:Life Cycle Stages; D016818:Nosema / Q000254:growth & development*; D010125:Ostreidae / Q000469:parasitology* / Q000502:physiology; D010049:Ovarian Diseases / Q000469:parasitology*; D011529:Protozoan Infections, Animal / Q000469:parasitology*; D012098:Reproduction; D012758:Shellfish / Q000469:parasitology*; D013170:Spores