Fifty-day-old fry of tilapia hybrids (Oreochromis aureus x niloticus) were placed in aquaria containing sediment with oocysts of Eimeria (sensu lato) vanasi Landsberg et Paperna. In the first 29 h after exposure sporulated oocysts in the stomach and free sporozoites in the gut could be found in examined fish. By 7 to 56 h after exposure, sporozoites, with their characteristic crystalloid body, were detected in intraepithélial lymphocyte-like and other leucocyte-like cells, but never in the epithelial cells. Infected cells were confined to the epithelial layer and did not enter the lamina propria. Within this time, some of the sporo-zoitcs divided by endodyogeny, once or twice in succession, to form daughter sporozoites. The parent’s sporozoite crystalline body was divided between the offspring of the primary and secondary divisions.
The genital pore of the female of Intoshia variabili Аleksandrov et Sljusarev, 1992 is located on a transverse ring of non-ciliated cells. Before copulation it is occupied by 6-7 cells that develop in the epithelium and that for a time are beneath the surface. When fully developed, these cells contain many electron-dense granules and their apical surface is covered with numerous microvilli. After copulation the granules disappear and the apical surface becomes smooth. The cells still form a plug closing the opening. After one larva pushes the pore cells out and escapes, others follow.
The tegument ultrastructure of the cestode Triaenophorus nodulosus has been studied in the stages of oncosphere, procercoid, plerocercoid and adult. The syncytium of primary tegument has glandular origin and is located in the peripheral areas of the oncosphere. The primary tegument degenerates at the initial stages of the procercoid development and is replaced with secondary tegument persisting throughout all following stages of the worm’s development. Two ways of microthrix formation on the body surface of procercoid were discovered. The formation of the cyst consisting of fibrillar material around the plerocercoid was observed. It fills spaces between numerous finger-like évaginations of plerocercoid’s tegument. The structural differentiation of tegument and microtriches was demonstrated on the scolex and all parts of strabila of T. nodulosus.
Endogenous development of Choleoeimeria rochalimai (Carini et Pinto, 1926) Lainson et Paperna, 1999 in the gall bladder of Hemidactylus mabouia (Moreau de Jonnes, 1818) front Belem, Brazil is reported at the fine structural level. Meronts and gamonts develop in the epithelial cells of the gall bladder. Infected cells become enlarged and displaced above the epithelial layer. Developing merozoites, dividing meronts and succession of developing microgamonts from initial nuclear division up to final microgamete differentiation are described. In addition to wall forming bodies, mature macrogamonts possess a large inclusion or cisterna with fine granular contents.
A new microsporidian species of the genus Glugea Thélohan, 1891 parasitising the marine teleost fish Cephalopholis hemistiktos Rüppell, collected from the Red Sea in Saudi Arabia, is described on the basis of microscopic and molecular procedures. Spherical and whitish xenoma were observed adhering to the intestinal wall. The numerous spores contained within these xenoma, were ovoid to pyriform and measured 4.3-6.0 µm (5.1 µm) in length and 1.8-2.9 µm (2.2 µm) in width. The spore's wall was composed of two thick layers, which were thinner in the area contacting the anchoring disk. The latter appeared at the spore's anterior pole, in an eccentric position to the longitudinal axis. A lamellar polaroplast surrounded the uncoiled portion of the polar filament projected to the basal region of the spore, giving rise to 26-29 turns with winding from the base to the anterior zone of the spore. The posterior vacuole, located at the spore's posterior pole, and surrounded by the polar filament coils, was irregular and composed of light material. Molecular analysis of the rRNA genes, including the ITS region, was performed using maximum parsimony, neighbour-joining and maximum likelihood methods. The ultrastructural features observed, combined with the phylogenetic data analysed, suggest this parasite to be a new species of the genus Glugea. This is the first species of this genus to be reported from Saudi Arabia and is herein named Glugea nagelia sp. n., Abdel-Azeem S. Abdel-Baki, Saleh Al-Quraishy, Sónia Rocha, Mohamed A. Dkhil, Graça Casal, Carlos Azevedo., and Obsahuje bibliografii