Utrastructural observations on Goussia metchnikovi (Laveran, 1897) in the spleen of gudgeon, Gobio gobio L.
ABSTRACT The ultrastructure of gamonts and sporulated oocysts of Goussia metchnikovi in the spleen of gudgeon, Gobio gobio from the river Lee, England is described. In developing microgamonts, small amylopectin granules were grouped centrally and nuclei were often arranged peripherally, close to the surface membrane. Nuclear chromatin condensed into peripheral dense portions that became the nuclei of flagellated microgametes, released to the parasitophorous vacuole. The cytoplasm of macrogametes had larger, scattered amylopectin granules, lipid globules and small electron-dense bodies, but no obvious wall forming bodies; peripheral vesicular structures with the appearance of mitochondria were also present and the parasitophorous vacuole contained flocculent material, but was otherwise free of structures. Sporulated oocysts contained four sporocysts and oocyst walls appeared to consist of a single membrane. Sporocyst walls showed a dehiscence suture, characteristic of the genus Goussia, which had filamentous extensions in places. The sporocyst wall comprised a dense inner layer and a thin outer layer with a fuzzy coat, separated by an electron lucent layer. Groups of oocysts were encapsulated by fibrous layers and inflammatory cells, and many sporocysts and their contained sporozoites showed evidence of elimination by the host.
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ABSTRACT: . Ultrastructural studies on the endogenous stages of Eimeria variabilis from the marine fish Cottus bubalis showed macrogamonts that resembled those of other fish coccidia except for small and large, probably protcinaceous, intracytoplasmic dense bodies. Similar dense bodies occurred in oocysts, but were not identified as wall forming bodies since many extruded from the contracted oocyst contents during sporulation. The thin, two-layered oocyst wall (20 nm across) may have derived from smooth endoplasmic reticulum and the plasma membrane of the late macrogamont. At sporogony, the oocyst wall frequently peeled inwards in scroll-like formations to leave a membrane 3-nm thick, possibly of host origin. Sporogony produced four uninucleate sporoblasts that developed with some asynchrony within a single oocyst. Sporoblasts were limited by a single membrane initially, and additions to this membrane, apparently from dense material and filaments outside the sporoblast, built up the sporocyst wall. An area of Stieda-like body formation was identified on the sporocyst wall and no other exit for sporozoites was seen. Full description of sporozoites, microgamonts and meronts awaits further study but similarities with those of other coccidia were noted.Journal of Fish Diseases 11/1990; 13(6):447-461. DOI:10.1111/j.1365-2761.1990.tb00804.x · 1.51 Impact Factor
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ABSTRACT: Eimeria degiustii and E. iroquoina were studied in natural infections of their mutual cyprinid hosts the common shiner, Notropis cornutus, and the fathead minnow, Pimephales promelas. Experimental infections involved lab-reared fathead minnows. Oocysts were acclimated to different temperatures to investigate the effects upon the parasites' development and infectivity.Eimeria degiustii occurred at 21% prevalence in common shiners 2 years of age or older. Development was parenteral. Gametogony was recorded during the winter in the spleen and oocysts were found primarily in this site.Viurtally all Notropis cornutus 4 to 5 weeks of age were infected with E. iroquoina. Fish 1 year old or older act as reservoirs of infections with about 30% prevalence. Eimeria iroquoina develops in the intestinal epithelium, primarily immediately posterior to the bile duct. During the winter autoinfection of the posterior intestine possibly occurs. Transmission of E. iroquoina from N. cornutus to P. promelas demonstrates this parasite's lack of rigid host specificity.Eimeria degiustii and E. iroquoina appear to minimize competition in mutual hosts by infecting different age-classes in different sites and by forming oocysts primarily at different times of year. Eimeria iroquoina is transmitted directly. Eimeria degiustii probably requires an invertebrate intermediate host.Canadian Journal of Zoology 02/2011; 60(5):764-775. DOI:10.1139/z82-106 · 1.35 Impact Factor
Folia parasitologica 02/1971; 18(4):289-94. · 1.21 Impact Factor