Ultrastrutural Morphology of Myxobolus testicularis sp. n., Parasite of the Testis of Hemiodopsis microlepis (Teleostei: Hemiodontidae) from the NE of Brazil

Jessica Tajdari ； Edilson Matos ； Ivete Mendonça ； Carlos Azevedo

《Acta Protozoologica》 44卷4期 (2005/12) Pp. 377-384

並列摘要

Myxobolus testicularis sp. n. was found within cyst-like structures in the testis of the freshwater fish Hemiodopsis microlepis Kner, 1859 (Teleostei, Hemiodontidae) in close contact with the testis stroma. The fish were collected in the Poty River, near the city of Teresina (State of Piauí, Brazil). Large spherical to ellipsoidal plasmodia up to 0.5 mm were filled with disporic pansporoblasts and mature spores. The plasmodial wall presented a sinuous outline surrounded by several fibroblasts and a continuous layer of numerous collagen fibrils. The plasmodia contained different proliferative stages. Early sporogenic cells were present in the cortical zone. Immature and mature spores were located more internally. Ellipsoidal spores measured 8.6±0.5 μm (n=30) length, 7.2±0.5 μm (n=15) width, and 2.7±0.4 μm (n=12) thickness. The anterior end of the spores contained two equal pyriform polar capsules measuring 3.5±0.3 μm (n=15) length, 1.7±0.4 μm (n=10) width, each with an isofilar polar filament with 5-6 turns obliquely to the longitudinal axis. The wall of the polar capsule was filled with a hyaline substance contrasting with the very dense internal matrix. The spores consisted of two equal valves forming the wall. The spore wall was surrounded by a dense and uniform layer with variable thickness (up to 0.6 μm) consisting of a complicated network of anastomosed microfibrils closely adhered to the wall. More externally, in the plasmodial matrix, the fibrils formed a looser network. Based on the ultrastructural morphology and specificity to the host species, we propose the creation of a new species, named Myxobolus testicularis sp. n.

並列關鍵字

fish parasite ； Myxobolus testicularis sp. n. ； Myxozoa ； ultrastructure