Light and electron microscopic observations of Leptotheca koreana n. sp. (Myxosporea) in the kidney of cultured rockfish Sebastes schlegeli

Abstract

The structure and sporogenesis of Leptotheca koreana n. sp. from cultured rockfish Sebastes schlegeli from South Korea were studied by light and transmission electron microscopy. Broadly oval spores and disporous pseudoplasmodia were observed in the lumen of renal tubules. Spores were 8.59 ± 1.25 µm in length, 13.42 ± 1.0 µm in width in sutural view and 8.13 ± 0.52 µm in thickness in the plane perpendicular to the suture. The width of each valve was always smaller than spore length. Two spherical polar capsules were equal in size (3.86 ± 0.45 µm in diameter) containing a polar filament with 6 to 7 turns, opening at the anterior end of the spore. Two uninucleate sporoplasms filled the spore cavity. The asynchronous division of secondary and tertiary cells and asynchronous development in spore formation of the present Leptotheca koreana resembled the disporous sphaerosporids. Cytoplasmic projections of pseudoplamodia were considered to be rhizoids, as they seem to strengthen the attachment to the epithelial cells of the renal tubules. The capsulogenic cells in early sporoblast had large amounts of rough endoplasmic reticulum but had a few Golgi apparatus.KEY WORDS: Leptotheca koreana n. sp. · Cultured marine fish · South KoreaResale or republication not permitted without written consent of the publisher

Ultrastructure and localisation of late-sporogonic developmental stages of Sphaerospora ranae (Myxosporea: Sphaerosporidae)

“…Interestingly, in both representatives of Lineage A for which ultrastructural data are available, S. epinepheli and S. sparidarum, distinct plasmodial projections apparently facilitating attachment of plasmodia to host epithelium are present (Supamattaya et al 1993, Sitjà-Bobadilla andAlvarezPellitero 2001). These projections markedly resemble probably homological projections in other renal myxosporeans from marine fish, for example Sphaerospora koreana (Cho et Kim, 2001) (syn. Leptotheca koreana), which is so similar to S. epinepheli and S. sparidarum in so many aspects (compare Supamattaya et al 1991, Cho and Kim 2001, Sitjà-Bobadilla and Alvarez-Pellitero 2001, that it is possible to assume that it is a representative of Lineage A.…”

“…These projections markedly resemble probably homological projections in other renal myxosporeans from marine fish, for example Sphaerospora koreana (Cho et Kim, 2001) (syn. Leptotheca koreana), which is so similar to S. epinepheli and S. sparidarum in so many aspects (compare Supamattaya et al 1991, Cho and Kim 2001, Sitjà-Bobadilla and Alvarez-Pellitero 2001, that it is possible to assume that it is a representative of Lineage A. However, plasmodial attachment projections are documented from a single B lineage sphaerosporid, S. truttae (Mcgeorge et al 1994(Mcgeorge et al , 1996, suggesting that plasmodial attachment projections might not be a unique trait of the marine Lineage A.…”