The genus Chloromyxum (Myxozoa: Myxosporea: Bivalvulida) is defined as having ridged or smooth bivalvular myxospores containing four polar capsules, with/without caudal filaments. Currently containing more than 140 nominal species, this genus is reasonably speciose with myxospores of unique but heterogeneous morphology. Recent phylogenetic studies have demonstrated its polyphyletic nature. During our myxosporean survey of freshwater fish, a new coelozoic myxosporean species, Chloromyxum trilineatum n. sp., was detected in the gall bladder of the pale chub, Zacco platypus (Cypriniformes: Cyprinidae), which originated from central Japan. Spores were subspherical, measuring 8.5-9.1 (8.8) μm in length, 7.6-8.2 (8.0) μm in width, and 6.8-7.8 (7.4) μm in thickness (n = 20). The valvular surface was smooth and three or four distinct ridges ran parallel to the suture line. Four almost equal polar capsules, 2.9-3.8 (3.3) μm in length and 1.6-2.4 (2.0) μm in width, assembled at the apical part of the spores. The partial nucleotide sequence of the 18S ribosomal RNA gene, 2014 bp in length, was closest to that of morphologically distinct Chloromyxum ellipticum, infecting the gall bladder of grass carp (Ctenopharyngodon idella) in China with 96.99% (1673/1725) identity and three insertion/deletion (indel) sites, followed by Chloromyxum legeri, infecting the gall bladder of common carp (Cyprinus carpio) in the Czech Republic with 89.97% (1803/2004) identity and 14 indel sites. Other myxosporean species, including Chloromyxum spp. from the gall bladder or urinary system of freshwater and marine fish, were phylogenetically distant from the present species.

• Klíčová slova
• 18S rDNA, Chloromyxum, Morphology, Myxozoa, Phylogeny, SEM, Zacco platypus,
• MeSH
• Cyprinidae parazitologie   MeSH
• fylogeneze MeSH
• Myxozoa klasifikace   genetika   MeSH
• nemoci ryb parazitologie   MeSH
• parazitární nemoci u zvířat parazitologie   MeSH
• ribozomální DNA genetika   MeSH
• RNA ribozomální 18S genetika   MeSH
• sekvence nukleotidů MeSH
• žlučník parazitologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Česká republika MeSH
• Čína MeSH
• Japonsko MeSH
• Názvy látek
• ribozomální DNA MeSH
• RNA ribozomální 18S MeSH

During a survey on the myxosporean fauna of Rajiformes from the Atlantic coast of Argentina, in waters off Buenos Aires Province (34°-42°S; 53°-62°W), the gall bladders of 217 specimens belonging to seven species of skates, representatives of two families, were examined. As a result, three species of Chloromyxum Mingazzini, 1890, namely C. atlantoraji n. sp., C. zearaji n. sp. and C. riorajum Azevedo, Casal, Garcia, Matos, Teles-Grilo and Matos, 2009 were found infecting three endemic host species, the spotback skate Atlantoraja castelnaui (Arhynchobatidae), the yellownose skate Zearaja chilensis (Rajidae) and the Rio skate Rioraja agassizii (Arhynchobatidae), respectively. These species were described based on myxospore morphology and morphometry characterization, as well as by providing their small subunit ribosomal DNA (SSU rDNA) sequences. The SSU rDNA-based phylogenetic analyses showed that these three species constituted a well-established monophyletic subclade within the marine Chloromyxum clade, while branches subtending the other Chloromyxum species were poorly resolved or unresolved, independently of the host taxonomic identities (Carchariniformes, Myliobatiformes, Orectolobiformes, Pristiophoriformes, Rajiformes, Squaliformes and Torpediniformes) and/or host geographic distribution (Atlantic coast of Portugal, Atlantic coast of the USA, Australian waters or Mediterranean Sea). The possible causes of these discrepancies are discussed, providing new insights into the phylogeny of the marine Chloromyxum clade.

Lors d’une étude de la faune des Myxozoaires des Rajiformes de la côte atlantique argentine, dans les eaux situées au large de la province de Buenos Aires (34°–42°S; 53°–62°O), les vésicules biliaires de 217 spécimens appartenant à sept espèces, représentants deux familles, ont été examinés. En conséquence, trois espèces de Chloromyxum Mingazzini, 1890, à savoir C. atlantoraji n. sp., C. zearaji n. sp. et C. riorajum Azevedo, Casal, Garcia, Matos, Teles-Grilo et Matos, 2009 ont été trouvées, infectant trois espèces hôtes endémiques, Atlantoraja castelnaui (Arhynchobatidae), Zearaja chilensis (Rajidae) et Rioraja agassizii (Arhynchobatidae), respectivement. Ces espèces sont décrites sur la base de la morphologie et de la morphométrie des myxospores, ainsi qu’en fournissant leurs petites séquences d’ADN ribosomal (SSU ADNr). Les analyses phylogénétiques basées sur l’ADNr SSU ont montré que ces trois espèces constituaient un sous-clade monophylétique bien établi dans le clade des Chloromyxum marins, tandis que les branches sous-jacentes aux autres espèces de Chloromyxum étaient mal ou non résolues, indépendamment des identités taxonomiques hôtes (Carchariniformes, Myliobatiformes, Orectolobiformes, Pristiophoriformes, Rajiformes, Squaliformes et Torpediniformes) et/ou de la répartition géographique de l’hôte (côte atlantique du Portugal, côte atlantique des États-Unis, eaux australiennes ou mer Méditerranée). Les causes possibles de ces divergences sont discutées, fournissant de nouvelles informations sur la phylogénie du clade des Chloromyxum marins.

• MeSH
• druhová specificita MeSH
• fylogeneze * MeSH
• mikroskopie elektronová rastrovací MeSH
• Myxozoa klasifikace   genetika   izolace a purifikace   MeSH
• nemoci ryb epidemiologie   parazitologie   MeSH
• oceány a moře MeSH
• parazitární nemoci u zvířat epidemiologie   parazitologie   MeSH
• rejnokovití parazitologie   MeSH
• ribozomální DNA genetika   MeSH
• sekvence nukleotidů MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Argentina epidemiologie   MeSH
• oceány a moře MeSH
• Názvy látek
• ribozomální DNA MeSH

Myxosporeans Chloromyxum cristatum, Chloromyxum fluviatile and Zschokkella nova (Myxozoa) are common gall bladder parasites of the cyprinid fishes frequently persisting as co-infections. Despite the fact that they are believed to be innocuous endocommensals, C. cristatum clearly displays the potential of a serious pathogen since it may pervade fish liver parenchyma and cause its necrosis. Employing the comparison of genetic distances among the myxosporean rDNA sequences and performing phylogenetic analyses, we demonstrate that cryptic species assemblages exist in C. fluviatile and Z. nova. Sequence comparison revealed that Chloromyxum legeri, previously assigned as a junior synonym of C. fluviatile, is a valid species. The same method is used to display the distinction of Z. nova isolates from China and the Czech Republic. We show that C. cristatum is not an assemblage of more species, and our results support the synonymy of Chloromyxum cyprini with C. cristatum. We have developed a multiplex PCR as an effective tool for the detection and discrimination of Z. nova, C. cristatum, and C. fluviatile. It is especially advantageous for the distinction of the non-mature plasmodia of both Chloromyxum species. This method also helped to assess the exact prevalence of these parasites in examined samples and enabled to select single-infected host samples for the intended population studies.

• MeSH
• druhová specificita MeSH
• fylogeneze MeSH
• Myxozoa klasifikace   genetika   izolace a purifikace   MeSH
• nemoci ryb parazitologie   MeSH
• parazitární nemoci u zvířat parazitologie   MeSH
• polymerázová řetězová reakce MeSH
• protozoální DNA genetika   MeSH
• ribozomální DNA genetika   izolace a purifikace   MeSH
• ryby parazitologie   MeSH
• sekvence nukleotidů MeSH
• sekvenční analýza DNA MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• protozoální DNA MeSH
• ribozomální DNA MeSH