Ultrastructure and phylogeny of Ceratomyxa diplodae (Myxosporea: Ceratomyxidae), from gall bladder of European seabass Dicentrarchus labrax

Abstract

The myxosporean parasite Ceratomyxa diplodae Lubat et al. 1989 sensu Sitjà-Bobadilla & Álvarez-Pellitero, 1993, originally described from the annular seabream Diplodus annularis in the Adriatic Sea, has subsequently been reported from several other sparid hosts, and also a moronid fish, the European seabass Dicentrarchus labrax from the Mediterranean Sea. Here, molecular identity and additional morphological data are given for this parasite infecting the gall bladder of D. labrax in a southern Portuguese fish farm. In the bile, disporic plasmodia were spherical to subspherical with a smooth surface membrane. Most myxospores were crescentshaped, 5.1 ± 0.5 (4.8−6.7) µm long (mean ± SD) and 21.9 ± 1.0 (20.4−23.9) µm thick; a few were more arcuate, 5.7 ± 0.4 (5.3−6.3) µm long and 17.3 ± 1.0 (16.3−19.1) µm thick. The wall consisted of 2 symmetrical valves united along a slightly curved suture line, with moderately tapering to rounded ends. Two spherical polar capsules, measuring 2.9 ± 0.3 (2.5−3.4) µm in diameter, contained a polar filament forming 8 to 9 coils organized in 2 rows. Host species, tissue tropism, and myxospore morphology supported species identification. Phylogenetic analyses of the small subunit ribosomal RNA sequence positioned the parasite among most sparid-infecting Ceratomyxa spp., suggesting the existence of a common ancestor for these species. The acquisition of molecular data from infections of C. diplodae in its original host and in other sparids is essential in order to ascertain if the morphological and biological variations found among reports of this parasite are intra-or inter-specific.

Life in a rock pool: Radiation and population genetics of myxozoan parasites in hosts inhabiting restricted spaces

“…Specific PCR assays were also essential for the exact assessment of Ceratomyxa spp. diversity in clinids, as frequent mixed infections, indeed common in myxozoans [ 17 , 40 ], complicated such evaluation. Present evidence of multiple Ceratomyxa spp.…”

“…This raises questions whether the observed variation is determined by deformations of their presumably thin-walled shell valves, a feature previously documented for some ceratomyxids [ 39 ], or alternatively is due to the concurrent infections of several Ceratomyxa species of different morphology, as mixed myxozoan infections [ 17 ], including those of Ceratomyxa spp. [ 40 ], are a common phenomenon.…”

Morphometeric criteria and partial sequence of the 18S rRNA gene of Ceratomyxa sultani n. sp. from the gallbladder of Upeneus margarethae in the Arabian Gulf, with a note on its seasonal prevalence

“…Consequently, in order to arrive at more reliable identifications, it is always worthwhile to take into account as many additional criteria as possible, such as the partial sequence of the SSU rDNA gene, host specificity and the geographical location (Fiala, 2006, Heiniger and Adlard, 2013, Kalatzis et al, 2013). In order to establish species novelty, therefore, it is now considered to be beat practice to use SSU rDNA data in combination with morphological and/or biological data (Heiniger and Adlard, 2013, Rocha et al, 2016). Following this perspective, we have here described a new species of Ceratomyxa using a combination of spore morphometric characters and 18S rDNA sequence data.…”

Glaukomchirurgie

“…Insofern gewinnt die Glaukomchirurgie zunehmend an Bedeutung und sollte deshalb grundsätzlich bei der Strategieplanung der Glaukomtherapie berücksichtigt werden. Besonders bei sehr hohen Ausgangsdruckwerten kann nach dem operativen Eingriff bei erzielten Druckwerten ≤ 15 mm Hg nicht nur eine Stabilität, sondern auch eine Verbesserung des funktionellen Zustandes erreicht werden [6,7]. Diese Chance sollte durchaus berücksichtigt und eine Operation nicht zu lange aufgeschoben werden.…”