Three Unicapsula species (Myxosporea: Trilosporidae) of Asian marine fishes, including the description of Unicapsula setoensis n. sp. in the yellowfin goby (Acanthogobius flavimanus) from the Inland Sea of Japan

Abstract

The myxosporean genus Unicapsula (Multivalvulida: Trilosporidae) is defined as having a spore with three unequal shell valves and polar capsules, of which one is prominent and the two other polar capsules are rudimentary. Genetic characterization of members of the genus, currently 11 nominal species, is, at present, unsatisfactory yet when comparing to the closely related genus Kudoa (Multivalvulida: Kudoidae). In the present study, we characterized long ribosomal RNA gene (rDNA) sequences of three Unicapsula spp., namely Unicapsula pyramidata, Unicapsula seriolae, and a novel myxosporean species, Unicapsula setoensis n. sp., from Asian fishes. Elongated plasmodia of U. pyramidata were found in the trunk muscle of Japanese threadfin breams, Nemipterus japonicus, fished off northern Vietnam in the South China Sea. Semitriangular spores, 5.5-6.4 μm in length and 5.6-9.6 μm in width, consisted of three shell valves with two caudal appendages, 7.2-7.4 μm in length. One prominent polar capsule, 2.0-2.4 μm in diameter, was located in the apical shell valve and two rudimentary polar capsules, 0.4-0.5 μm in diameter, in each caudal shell valve. Elongated plasmodia of U. seriolae were found in the trunk muscle of a greater yellowtail, Seriola dumerili, aquacultured in Japan. Semispherical spores, 5.9-7.4 μm in length and 6.3-7.4 μm in width, also consisted of three shell valves and one prominent polar capsule, 3.4-3.8 μm in diameter, with two rudimentary polar capsules, 0.7-1.0 μm in diameter. Plasmodia of U. setoensis n. sp. were found in the trunk muscle of yellowfin gobies, Acanthogobius flavimanus, fished off Hofu, Yamaguchi Prefecture, in the Inland Sea of Japan. Semispherical spores, 5.6-6.9 μm in diameter, displayed three shell valves and one prominent and two rudimentary polar capsules. The former functional polar capsule was 1.9-2.5 μm in diameter and extruded a 9.4-13.8-μm-long polar filament. Nearly the whole length of the 18S rDNA and more than 2,200 bp of the 28S rDNA of the three Unicapsula spp. were sequenced along with nucleotide sequences of the 5.8S rDNA and internal transcribed spacer-1 and spacer-2 of U. pyramidata and U. setoensis n. sp. Molecular genetic analyses supported the morphological species differentiation of U. pyramidata and U. seriolae, and the distinctness of U. setoensis n. sp. from hitherto known species.

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

“…Morphological data obtained from this study showed that U. fatimae was morphologically comparable to what is termed as the “sub-spherical” Unicapsula species that include Unicapsula andersenae Miller and Adlard 2013 , Unicapsula seriolae Lester 1982 , Unicapsula pflughfelderi Schubert et al 1975 , Unicapsula galeata Naidjenova and Zaika 1970 , Unicapsula shulmani Aseeva and Krasin 2001 , Unicapsula pacifica Aseeva and Krasin 2001 , Unicapsula setoensis Tomochi et al 2014 , and Unicapsula chirocentrusi Sarkar 1984 , and was morphologically distinct from all other Unicapsula species. U. andersenae from (Argyrosomus japonicus) Temminck and Schlegel 1843 , (Acanthopagrus australis) Günther 1859; ( Eleutheronema tetradactylum) Shaw, 1804; (Lutjanus russellii) Bleeker 1849 and (Sillago ciliata) Cuvier 1829 from Australia was genetically the most closely related species to U. fatimae in the BLAST search with approximately 97 % similarity.…”

“…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 ). 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 ).…”

“…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 ). Although marine parasitological investigations in the Arabian Peninsula region dates back to the 1980s, the myxozoan parasite fauna received only most recent attention, resulting in several new species being recorded from various marine hosts, caught off the coasts of the Kingdom of Saudi Arabia (Red Sea and Arabian Gulf) (Zhang et al 2014 ; Mansour et al 2014 , 2015a , 2015b ).…”

Phylogenetic characterisation of seven Unicapsula spp. (Myxozoa: Myxosporea: Multivalvulida) from commercial fish in southern China and Japan

“…Davis (1924) referred to infected fish as ‘wormy halibut’, referring to their heavy parasite load. The second species to be described, Unicapsula galeata Naidjenova et Zaika, 1970, was discovered in the trunk muscle of the whitesaddle goatfish Parupeneus ciliates (Lacepède, 1802) more than 40 years later after the erection of the genus (Naidjenova and Zaika, 1970), and a total of only 13 species have been described to date (Schubert et al ., 1975; Alama-Bermejo et al ., 2009; Miller and Adlard, 2013; Tomochi et al ., 2014; Yokoyama et al ., 2014; Al-Jufaili et al ., 2016). As partially reflected in a limited number (only 13) of the currently recognized Unicapsula spp., Miller and Adlard (2013) suspected that the richness of Unicapsula spp.…”

Первые Данные О двустворчатых Миксоспоридиях Кефалевых Рыб Залива Нячанг (Вьетнам)

“…), которые паразитируют в груперах и баррамунди [19]. Первые исследования многостворчатых миксоспоридий Восточного моря с привлечением методов молекулярной генетики охватили изучение Unicapsula pyramidata в Nemipterus japonicus [18], Kudoa monodactyli из Monodactylus argenteus [14] и Kudoa scomberomori из Scomberomorus guttatus [15]. Рыб обследовали методом неполного паразитологического вскрытия [2].…”