Saleh Al-Quraishy

Choleoeimeria bunopusi sp. n. is described from the gall bladder of the tuberculated gecko Bunopus tuberculatus in Saudi Arabia. The prevalence of infection was 13.3% (2/15). Oocysts were ellipsoidal and measured 31 (30–33) × 21 (20–22) μm. Sporocysts were dizoic, elliptical in shape and measured 12 (11–13) × 7 (6–8) μm. The endogenous development was confined to the gall bladder epithelium. The hypertrophic parasitized biliary epithelium either remained in one layer or became stratified. Meronts, gamonts, and young oocysts were detected.

Genus Perkinsus Levine, 1978 (Alveolata, Perkinsidae) an intracellular pathogenic parasite is described from the mantle and gill filaments of a commercially important clam, Meretrix meretrix, collected from the Arabian Gulf, Saudi Arabia. This genus contains currently seven named species: P. marinus, P. olseni (P. atlanticus), P. chesapeaki (P. andrewsi), P. mediterraneus, P. honshuensis, P. beihaiensis and P. qugwadi. Meanwhile, some unnamed Perkinsus sp. have been described in wide variety of mollusc species. Ultrastructural features of Perkinsus sp. trophozites and the host reaction are described. The different developmental stages of trophozoites appeared as single or grouped cells surrounded by amorphous material that constituted cysts or nodules randomly distributed throughout the connective tissue of the mantle. The early trophozoites were generally spherical to ellipsoidal with a circular nucleus containing a prominent central nucleolus. The cytoplasm had several small vacuoles which coalesce to form a great vacuole in the later trophozoites and the nucleus becomes eccentric. Some lomosomes were observed between the wall and the plasmalemma of trophozoites. A large number of degraded and pyknotic cell and several cellular structure with lysed aspects were encountered in the surrounding area near the cysts. Ultrastructural data showed that the lysed granular cells and the coalescence of the granules result in the cyst that encapsulates various trophozoites. In the current study, we describe for the first time the presence of Perkinsus sp. as well as the host reaction in clams from the Saudi Arabian coasts.

The morphology, morphogenesis and infraciliature of two marine euplotid ciliates, Euplotes dammamensis n. sp. and Euplotes balteatus (Dujardin, 1841) Kahl, 1932, isolated from a sandy beach of the Arabian Gulf, Saudi Arabia, were investigated using observations in vivo and protargol-impregnation methods. Euplotes dammamensis n. sp. is characterized by a combination of features including its huge body size (100–170 × 80–120 μm), 10 conspicuous dorsal ridges, 10 normal-sized frontoventral and two marginal cirri, and 11 dorsal kineties. Euplotes balteatus is mainly characterized by 10 frontoventral, two caudal, and two left marginal cirri, 7–10 dorsal kineties and 5–7 prominent dorsal ridges as well as double-eurystomus silverline system. The small subunit rRNA (SSU-rRNA) gene sequences were determined for both species and phylogenetic analyses based on these data indicated that E. dammamensis is most closely related to E. parabalteatus Jiang et al., 2010, and E. balteatus clusters with E. plicatum Valbonesi et al., 1997, E. orientalis Jiang et al., 2010, and E. bisulcatus Kahl, 1932.

This study used light and electron microscopy to describe a myxosporean, polysporic, histozoic plasmodium infecting the gill filaments of the freshwater teleost, Semaprochilodus insignis, specimens of which were collected from the Trombetas River (Central Amazonian Region, Brazil). Ultrastructural analyses of the fish-infecting spores identified the parasite as Myxobolus insignis, an organism that occurs within whitish unequal-sized plasmodia located in the intralamellar epithelium of the gill. Based on the observed morphological and ultrastructural features of the plasmodia in this study three stages in the plasmodial evolution were distinguished, related to the sporogonic stages of Myxobolus insignis. The plasmodium walls were also found to constitute a number of layers of fibroblasts, surrounded by collagen fibres, which displayed different morphological arrangements according to the different phases of evolution. This represents the first time such ultrastructural features have been described in detail for Myxobolus insignis plasmodia and offers potentially significant points of comparison with plasmodia from other species of myxosporea.