Morphological and molecular redescription of the myxozoan Unicapsula pflugfelderiSchubert, Sprague & Reinboth 1975 from two teleost hosts in the Mediterranean. A review of the genus Unicapsula Davis 1924

Abstract

Elongate plasmodia with myxosporean spores belonging to the genus Unicapsula, Davis, 1924 were found in the skeletal muscle of the striped seabream, Lithognathus mormyrus (L.), a candidate for the mediterranean aquaculture. The only species of Unicapsula described from the Mediterranean is Unicapsula pflugfelderi Schubert et al. 1975, which occurs in the picarel, Spicara smaris (L.). For morphological and molecular comparison of U. pflugfelderi from S. smaris with Unicapsula sp. from L. mormyrus measurements of plasmodia and spores, ultrastructural details and 18S and 28S rDNA sequences were analysed. Whereas plasmodia were 2-3 times larger in S. smaris than in L. mormyrus (length 2.47-0.81 mm; width 0.22-0.09 mm; P = 0.000), spore morphology showed minor differences and both 18S and 28S rDNA sequences were 100% identical identifying the myxozoan as U. pflugfelderi. Scanning electron microscopy of the spores revealed a different shell valve distribution than the one used for the diagnosis of the genus Unicapsula. This resulted in a review of the genus Unicapsula dividing it into two morphological groups of different spore valve arrangement. TEM revealed the presence of a yet undescribed crystalline structure in the sporoplasm of the spores.

3D Morphology, Ultrastructure and Development of Ceratomyxa puntazzi Stages: First Insights into the Mechanisms of Motility and Budding in the Myxozoa

“…The vesicular body observed in the present study was previously reported in Unicapsula pflugfelderi where vesicles measured 40–60 nm. In U. pflugfelderi the vesicular body was also found in close vicinity to developing polar capsules, and a secretory function was suggested [60]. Due to its location and its vesicular structure it is suggested that the presence and function of the vesicular body is related to capsulogenesis, possibly secreting carbohydrates or other substances required for polar capsule formation.…”

Morphological, ultrastructural, and molecular description of Unicapsula fatimae n. sp. (Myxosporea: Trilosporidae) of whitespotted rabbitfish (Siganus canaliculatus) in Omani waters

“…Spores were observed using Nomarski differential interference contrasting illumination at magnification of ×200–1600, using oil immersion to study and describe the morphology of mature spores. Several photomicrographs were obtained using Olympus CellDimension© imaging software to obtain measurements of mature spores according to Alama-Berjamo et al ( 2009 ). In addition, spore apical length and width were obtained as shown in Fig.…”

“…Members of the genus Unicapsula (Davis 1924) are multivalvulids belonging to the family Trilosporidae, which accommodate myxosporean parasites that have three valves, each bearing a polar capsule (Lom and Dykova 2006 ). Unicapsula species are unique among other Trilosporidae because only one of the three polar capsules is fully developed and functional, whereas the remaining two are rudimentary and barely visible (Alama-Berjamo et al 2009 ; Miller and Adlard 2013 ). Since the description of the genus and the type species in 1924 by Davis, a total of 12 species of Unicapsula have been recorded from different localities and a wide range of marine host species (Naidjenova and Zaika 1970 ; Schubert et al 1975 ; Sarkar 1984 ; Sarkar 1999 ; Diebakate et al 1999 ; Miller and Adlard 2013 ; Tomochi et al 2014 ).…”

“…Since the description of the genus and the type species in 1924 by Davis, a total of 12 species of Unicapsula have been recorded from different localities and a wide range of marine host species (Naidjenova and Zaika 1970 ; Schubert et al 1975 ; Sarkar 1984 ; Sarkar 1999 ; Diebakate et al 1999 ; Miller and Adlard 2013 ; Tomochi et al 2014 ). Similar to their closely related group, the Kudoidae, some members of Unicapsula have been associated with negative impact on their hosts mostly associated with esthetic issues involving macroscopic pseudocysts or myoliquefaction (Lester 1982 ; Alama-Berjamo et al 2009 ; Miller and Adlard 2013 ). Although the majority of species belonging to this genus has been detected from the musculature (Miller and Adlard 2013 ; Tomochi et al 2014 ), some have been detected from other organs such as the gills (Diebakate et al 1999 ), kidney (Sarkar 1999 ), and urinary bladder (Naidjenova and Zaika 1970 ).…”

Severe glomerular disease in juvenile grey snapper Lutjanus griseus L. in the Gulf of Mexico caused by the myxozoan Sphaerospora motemarini n. sp.

“…Some spore preparations were fixed in methanol and incubated with DAPI overnight to be able to count the number of sporoplasms in the spores. Lysine-coated coverslips with spores were fixed in 2.5% glutaraldehyde and processed for scanning electron microscopy (SEM) as described in Alama-Bermejo et al (2009). For molecular analyses, blood obtained from the caudal vein and small kidney pieces of each fish were fixed in 100% ethanol.…”