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Árni Kristmundsson - One of the best experts on this subject based on the ideXlab platform.
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Studies of Myxidium giardi Cépède, 1906 infections in Icelandic eels identifies a genetically diverse clade of Myxosporeans that represents the Paramyxidium n. g. (Myxosporea: Myxidiidae)
Parasites & Vectors, 2018Co-Authors: Mark A Freeman, Árni KristmundssonAbstract:BackgroundThe Myxosporean Myxidium giardi Cépède, 1906 was described infecting the kidney of the European eel, Anguilla anguilla (L.), having spindle-shaped Myxospores and terminal sub-spherical polar capsules. Since then, numerous anguillid eels globally have been documented to have similar Myxidium infections. Many of these have been identified using the morphological features of Myxospores or by the location of infection in the host, and some have been subsequently synonymised with M. giardi. Therefore, it is not clear whether M. giardi is a widely distributed parasite, infecting numerous species of eels, in multiple organs, or whether some infections represent other, morphologically similar but different species of Myxosporeans. The aim of the present study was to assess the status of M. giardi infections in Icelandic eels, and related fish hosts in Malaysia and to use spore morphology and molecular techniques to evaluate the diversity of Myxosporeans present.ResultsThe morphologies of the Myxospores from Icelandic eels were very similar but the overall dimensions were significantly different from the various tissue locations. Myxospores from the kidney of the Malaysian tarpon, Megalops cyprinoides (Broussonet), were noticeably smaller. However, the SSU rDNA sequences from the different tissues locations in eels, were all very distinct, with percentage similarities ranging from 92.93% to as low as 89.8%, with the sequence from Malaysia being even more dissimilar. Molecular phylogenies consistently placed these sequences together in a clade that we refer to as the Paramyxidium clade that is strongly associated with the Myxidium clade (sensu stricto). We erect the genus Paramyxidium n. g. (Myxidiidae) to accommodate these histozoic taxa, and transfer Myxidium giardi as Paramyxidium giardi Cépède, 1906 n. comb. as the type-species.ConclusionsThere is not a single species of Myxidium (M. giardi) causing systemic infections in eels in Iceland. There are three species, confirmed with a robust phylogeny, one of which represents Paramyxidium giardi n. comb. Additional species probably exist that infect different tissues in the eel and the site of infection in the host fish is an important diagnostic feature for this group (Paramyxidium n. g. clade). Myxospore morphology is generally conserved in the Paramyxidium clade, although actual spore dimensions can vary between some species. Paramyxidium spp. are currently only known to infect fishes from the Elopomorpha.
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studies of myxidium giardi cepede 1906 infections in icelandic eels identifies a genetically diverse clade of Myxosporeans that represents the paramyxidium n g Myxosporea myxidiidae
Parasites & Vectors, 2018Co-Authors: Mark A Freeman, Árni KristmundssonAbstract:The Myxosporean Myxidium giardi Cepede, 1906 was described infecting the kidney of the European eel, Anguilla anguilla (L.), having spindle-shaped Myxospores and terminal sub-spherical polar capsules. Since then, numerous anguillid eels globally have been documented to have similar Myxidium infections. Many of these have been identified using the morphological features of Myxospores or by the location of infection in the host, and some have been subsequently synonymised with M. giardi. Therefore, it is not clear whether M. giardi is a widely distributed parasite, infecting numerous species of eels, in multiple organs, or whether some infections represent other, morphologically similar but different species of Myxosporeans. The aim of the present study was to assess the status of M. giardi infections in Icelandic eels, and related fish hosts in Malaysia and to use spore morphology and molecular techniques to evaluate the diversity of Myxosporeans present. The morphologies of the Myxospores from Icelandic eels were very similar but the overall dimensions were significantly different from the various tissue locations. Myxospores from the kidney of the Malaysian tarpon, Megalops cyprinoides (Broussonet), were noticeably smaller. However, the SSU rDNA sequences from the different tissues locations in eels, were all very distinct, with percentage similarities ranging from 92.93% to as low as 89.8%, with the sequence from Malaysia being even more dissimilar. Molecular phylogenies consistently placed these sequences together in a clade that we refer to as the Paramyxidium clade that is strongly associated with the Myxidium clade (sensu stricto). We erect the genus Paramyxidium n. g. (Myxidiidae) to accommodate these histozoic taxa, and transfer Myxidium giardi as Paramyxidium giardi Cepede, 1906 n. comb. as the type-species. There is not a single species of Myxidium (M. giardi) causing systemic infections in eels in Iceland. There are three species, confirmed with a robust phylogeny, one of which represents Paramyxidium giardi n. comb. Additional species probably exist that infect different tissues in the eel and the site of infection in the host fish is an important diagnostic feature for this group (Paramyxidium n. g. clade). Myxospore morphology is generally conserved in the Paramyxidium clade, although actual spore dimensions can vary between some species. Paramyxidium spp. are currently only known to infect fishes from the Elopomorpha.
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Studies of Myxidium giardi Cépède, 1906 infections in Icelandic eels identifies a genetically diverse clade of Myxosporeans that represents the Paramyxidium n. g. (Myxosporea: Myxidiidae)
Parasites & vectors, 2018Co-Authors: Mark A Freeman, Árni KristmundssonAbstract:Background The Myxosporean Myxidium giardi Cepede, 1906 was described infecting the kidney of the European eel, Anguilla anguilla (L.), having spindle-shaped Myxospores and terminal sub-spherical polar capsules. Since then, numerous anguillid eels globally have been documented to have similar Myxidium infections. Many of these have been identified using the morphological features of Myxospores or by the location of infection in the host, and some have been subsequently synonymised with M. giardi. Therefore, it is not clear whether M. giardi is a widely distributed parasite, infecting numerous species of eels, in multiple organs, or whether some infections represent other, morphologically similar but different species of Myxosporeans. The aim of the present study was to assess the status of M. giardi infections in Icelandic eels, and related fish hosts in Malaysia and to use spore morphology and molecular techniques to evaluate the diversity of Myxosporeans present. Results The morphologies of the Myxospores from Icelandic eels were very similar but the overall dimensions were significantly different from the various tissue locations. Myxospores from the kidney of the Malaysian tarpon, Megalops cyprinoides (Broussonet), were noticeably smaller. However, the SSU rDNA sequences from the different tissues locations in eels, were all very distinct, with percentage similarities ranging from 92.93% to as low as 89.8%, with the sequence from Malaysia being even more dissimilar. Molecular phylogenies consistently placed these sequences together in a clade that we refer to as the Paramyxidium clade that is strongly associated with the Myxidium clade (sensu stricto). We erect the genus Paramyxidium n. g. (Myxidiidae) to accommodate these histozoic taxa, and transfer Myxidium giardi as Paramyxidium giardi Cepede, 1906 n. comb. as the type-species. Conclusions There is not a single species of Myxidium (M. giardi) causing systemic infections in eels in Iceland. There are three species, confirmed with a robust phylogeny, one of which represents Paramyxidium giardi n. comb. Additional species probably exist that infect different tissues in the eel and the site of infection in the host fish is an important diagnostic feature for this group (Paramyxidium n. g. clade). Myxospore morphology is generally conserved in the Paramyxidium clade, although actual spore dimensions can vary between some species. Paramyxidium spp. are currently only known to infect fishes from the Elopomorpha.
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Histozoic Myxosporeans infecting the stomach wall of elopiform fishes represent a novel lineage, the Gastromyxidae
Parasites & vectors, 2015Co-Authors: Mark A Freeman, Árni KristmundssonAbstract:Traditional studies on Myxosporeans have used Myxospore morphology as the main criterion for identification and taxonomic classification, and it remains important as the fundamental diagnostic feature used to confirm Myxosporean infections in fish and other vertebrate taxa. However, its use as the primary feature in systematics has led to numerous genera becoming polyphyletic in subsequent molecular phylogenetic analyses. It is now known that other features, such as the site and type of infection, can offer a higher degree of congruence with molecular data, albeit with its own inconsistencies, than basic Myxospore morphology can reliably provide. Histozoic gastrointestinal Myxosporeans from two elopiform fish from Malaysia, the Pacific tarpon Megalops cyprinoides and the ten pounder Elops machnata were identified and described using morphological, histological and molecular methodologies. The Myxospore morphology of both species corresponds to the generally accepted Myxidium morphotype, but both had a single nucleus in the sporoplasm and lacked valvular striations. In phylogenetic analyses they were robustly grouped in a discrete clade basal to Myxosporeans, with similar shaped Myxospores, described from gill monogeneans, which are located at the base of the multivalvulid clade. New genera Gastromyxum and Monomyxum are erected to accommodate these Myxosporean taxa from fish and gill monogeneans respectively. Each are placed in a new family, the Gastromyxidae with Gastromyxum as the type genus and Monomyxidae with Monomyxum as the type genus. To improve modern systematics of the Myxosporeans it is clear that a combination of biological, ecological, morphological and molecular data should be used in descriptive studies, and the naming and redistribution of taxa and genera is going to be necessary to achieve this. Here we demonstrate why some Myxidium-shaped Myxospores should not be included in the family Myxidiidae, and create two new families to accommodate them based on their site of infection, host biology / ecology, DNA sequence data and morphological observations. Subsequent descriptive works need to follow a similar course if we are going to create a prevailing and workable systematic structure for the Myxosporea.
Mark A Freeman - One of the best experts on this subject based on the ideXlab platform.
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Studies of Myxidium giardi Cépède, 1906 infections in Icelandic eels identifies a genetically diverse clade of Myxosporeans that represents the Paramyxidium n. g. (Myxosporea: Myxidiidae)
Parasites & Vectors, 2018Co-Authors: Mark A Freeman, Árni KristmundssonAbstract:BackgroundThe Myxosporean Myxidium giardi Cépède, 1906 was described infecting the kidney of the European eel, Anguilla anguilla (L.), having spindle-shaped Myxospores and terminal sub-spherical polar capsules. Since then, numerous anguillid eels globally have been documented to have similar Myxidium infections. Many of these have been identified using the morphological features of Myxospores or by the location of infection in the host, and some have been subsequently synonymised with M. giardi. Therefore, it is not clear whether M. giardi is a widely distributed parasite, infecting numerous species of eels, in multiple organs, or whether some infections represent other, morphologically similar but different species of Myxosporeans. The aim of the present study was to assess the status of M. giardi infections in Icelandic eels, and related fish hosts in Malaysia and to use spore morphology and molecular techniques to evaluate the diversity of Myxosporeans present.ResultsThe morphologies of the Myxospores from Icelandic eels were very similar but the overall dimensions were significantly different from the various tissue locations. Myxospores from the kidney of the Malaysian tarpon, Megalops cyprinoides (Broussonet), were noticeably smaller. However, the SSU rDNA sequences from the different tissues locations in eels, were all very distinct, with percentage similarities ranging from 92.93% to as low as 89.8%, with the sequence from Malaysia being even more dissimilar. Molecular phylogenies consistently placed these sequences together in a clade that we refer to as the Paramyxidium clade that is strongly associated with the Myxidium clade (sensu stricto). We erect the genus Paramyxidium n. g. (Myxidiidae) to accommodate these histozoic taxa, and transfer Myxidium giardi as Paramyxidium giardi Cépède, 1906 n. comb. as the type-species.ConclusionsThere is not a single species of Myxidium (M. giardi) causing systemic infections in eels in Iceland. There are three species, confirmed with a robust phylogeny, one of which represents Paramyxidium giardi n. comb. Additional species probably exist that infect different tissues in the eel and the site of infection in the host fish is an important diagnostic feature for this group (Paramyxidium n. g. clade). Myxospore morphology is generally conserved in the Paramyxidium clade, although actual spore dimensions can vary between some species. Paramyxidium spp. are currently only known to infect fishes from the Elopomorpha.
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studies of myxidium giardi cepede 1906 infections in icelandic eels identifies a genetically diverse clade of Myxosporeans that represents the paramyxidium n g Myxosporea myxidiidae
Parasites & Vectors, 2018Co-Authors: Mark A Freeman, Árni KristmundssonAbstract:The Myxosporean Myxidium giardi Cepede, 1906 was described infecting the kidney of the European eel, Anguilla anguilla (L.), having spindle-shaped Myxospores and terminal sub-spherical polar capsules. Since then, numerous anguillid eels globally have been documented to have similar Myxidium infections. Many of these have been identified using the morphological features of Myxospores or by the location of infection in the host, and some have been subsequently synonymised with M. giardi. Therefore, it is not clear whether M. giardi is a widely distributed parasite, infecting numerous species of eels, in multiple organs, or whether some infections represent other, morphologically similar but different species of Myxosporeans. The aim of the present study was to assess the status of M. giardi infections in Icelandic eels, and related fish hosts in Malaysia and to use spore morphology and molecular techniques to evaluate the diversity of Myxosporeans present. The morphologies of the Myxospores from Icelandic eels were very similar but the overall dimensions were significantly different from the various tissue locations. Myxospores from the kidney of the Malaysian tarpon, Megalops cyprinoides (Broussonet), were noticeably smaller. However, the SSU rDNA sequences from the different tissues locations in eels, were all very distinct, with percentage similarities ranging from 92.93% to as low as 89.8%, with the sequence from Malaysia being even more dissimilar. Molecular phylogenies consistently placed these sequences together in a clade that we refer to as the Paramyxidium clade that is strongly associated with the Myxidium clade (sensu stricto). We erect the genus Paramyxidium n. g. (Myxidiidae) to accommodate these histozoic taxa, and transfer Myxidium giardi as Paramyxidium giardi Cepede, 1906 n. comb. as the type-species. There is not a single species of Myxidium (M. giardi) causing systemic infections in eels in Iceland. There are three species, confirmed with a robust phylogeny, one of which represents Paramyxidium giardi n. comb. Additional species probably exist that infect different tissues in the eel and the site of infection in the host fish is an important diagnostic feature for this group (Paramyxidium n. g. clade). Myxospore morphology is generally conserved in the Paramyxidium clade, although actual spore dimensions can vary between some species. Paramyxidium spp. are currently only known to infect fishes from the Elopomorpha.
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Studies of Myxidium giardi Cépède, 1906 infections in Icelandic eels identifies a genetically diverse clade of Myxosporeans that represents the Paramyxidium n. g. (Myxosporea: Myxidiidae)
Parasites & vectors, 2018Co-Authors: Mark A Freeman, Árni KristmundssonAbstract:Background The Myxosporean Myxidium giardi Cepede, 1906 was described infecting the kidney of the European eel, Anguilla anguilla (L.), having spindle-shaped Myxospores and terminal sub-spherical polar capsules. Since then, numerous anguillid eels globally have been documented to have similar Myxidium infections. Many of these have been identified using the morphological features of Myxospores or by the location of infection in the host, and some have been subsequently synonymised with M. giardi. Therefore, it is not clear whether M. giardi is a widely distributed parasite, infecting numerous species of eels, in multiple organs, or whether some infections represent other, morphologically similar but different species of Myxosporeans. The aim of the present study was to assess the status of M. giardi infections in Icelandic eels, and related fish hosts in Malaysia and to use spore morphology and molecular techniques to evaluate the diversity of Myxosporeans present. Results The morphologies of the Myxospores from Icelandic eels were very similar but the overall dimensions were significantly different from the various tissue locations. Myxospores from the kidney of the Malaysian tarpon, Megalops cyprinoides (Broussonet), were noticeably smaller. However, the SSU rDNA sequences from the different tissues locations in eels, were all very distinct, with percentage similarities ranging from 92.93% to as low as 89.8%, with the sequence from Malaysia being even more dissimilar. Molecular phylogenies consistently placed these sequences together in a clade that we refer to as the Paramyxidium clade that is strongly associated with the Myxidium clade (sensu stricto). We erect the genus Paramyxidium n. g. (Myxidiidae) to accommodate these histozoic taxa, and transfer Myxidium giardi as Paramyxidium giardi Cepede, 1906 n. comb. as the type-species. Conclusions There is not a single species of Myxidium (M. giardi) causing systemic infections in eels in Iceland. There are three species, confirmed with a robust phylogeny, one of which represents Paramyxidium giardi n. comb. Additional species probably exist that infect different tissues in the eel and the site of infection in the host fish is an important diagnostic feature for this group (Paramyxidium n. g. clade). Myxospore morphology is generally conserved in the Paramyxidium clade, although actual spore dimensions can vary between some species. Paramyxidium spp. are currently only known to infect fishes from the Elopomorpha.
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Histozoic Myxosporeans infecting the stomach wall of elopiform fishes represent a novel lineage, the Gastromyxidae
Parasites & vectors, 2015Co-Authors: Mark A Freeman, Árni KristmundssonAbstract:Traditional studies on Myxosporeans have used Myxospore morphology as the main criterion for identification and taxonomic classification, and it remains important as the fundamental diagnostic feature used to confirm Myxosporean infections in fish and other vertebrate taxa. However, its use as the primary feature in systematics has led to numerous genera becoming polyphyletic in subsequent molecular phylogenetic analyses. It is now known that other features, such as the site and type of infection, can offer a higher degree of congruence with molecular data, albeit with its own inconsistencies, than basic Myxospore morphology can reliably provide. Histozoic gastrointestinal Myxosporeans from two elopiform fish from Malaysia, the Pacific tarpon Megalops cyprinoides and the ten pounder Elops machnata were identified and described using morphological, histological and molecular methodologies. The Myxospore morphology of both species corresponds to the generally accepted Myxidium morphotype, but both had a single nucleus in the sporoplasm and lacked valvular striations. In phylogenetic analyses they were robustly grouped in a discrete clade basal to Myxosporeans, with similar shaped Myxospores, described from gill monogeneans, which are located at the base of the multivalvulid clade. New genera Gastromyxum and Monomyxum are erected to accommodate these Myxosporean taxa from fish and gill monogeneans respectively. Each are placed in a new family, the Gastromyxidae with Gastromyxum as the type genus and Monomyxidae with Monomyxum as the type genus. To improve modern systematics of the Myxosporeans it is clear that a combination of biological, ecological, morphological and molecular data should be used in descriptive studies, and the naming and redistribution of taxa and genera is going to be necessary to achieve this. Here we demonstrate why some Myxidium-shaped Myxospores should not be included in the family Myxidiidae, and create two new families to accommodate them based on their site of infection, host biology / ecology, DNA sequence data and morphological observations. Subsequent descriptive works need to follow a similar course if we are going to create a prevailing and workable systematic structure for the Myxosporea.
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Myxosporean hyperparasites of gill monogeneans are basal to the Multivalvulida
Parasites & vectors, 2011Co-Authors: Mark A Freeman, Andrew P. ShinnAbstract:Background: Myxosporeans are known from aquatic annelids but parasitism of platyhelminths by Myxosporeans has not been widely reported. Hyperparasitism of gill monogeneans by Myxidium giardi has been reported from the European eel and Myxidium-like hyperparasites have also been observed during studies of gill monogeneans from Malaysia and Japan. The present study aimed to collect new hyperparasite material from Malaysia for morphological and molecular descriptions. In addition, PCR screening of host fish was undertaken to determine whether they are also hosts for the Myxosporean. Results: Heavy Myxosporean infections were observed in monogeneans from two out of 14 fish and were detected from a further five fish using specific PCRs and pooled monogenean DNA. Positive DNA isolates were sequenced and were from a single species of Myxosporean. Myxospore morphology was consistent with Myxidium with histozoic development in the parenchymal tissues of the monogenean. Simultaneous infections in the fish could not be confirmed microscopically; however, identical Myxosporean DNA could be amplified from kidney, spleen and intestinal tract tissues using the specific PCR. Small subunit (SSU) rDNA for the Myxosporean was amplified and was found to be most similar (92%) to that of another hyperparasitic Myxosporean from a gill monogenean from Japan and to numerous multivalvulidan Myxosporeans from the genus Kudoa (89-91%). Phylogenetic analyses placed the hyperparasite sequence basally to clades containing Kudoa, Unicapsula and Sphaerospora. Conclusions: The Myxosporean infecting the gill monogenean, Diplectanocotyla gracilis, from the Indo-Pacific tarpon, Megalops cyprinoides, is described as a new species, Myxidium incomptavermi, based on a histozoic development in the monogenean host and its phylogenetic placement. We have demonstrated for the first time that a Myxosporean hyperparasite of gill monogeneans is detectable in the fish host. However, Myxospores could not be isolated from the fish and confirmation was by PCR alone. The relationship between the Myxosporean infection in gill monogeneans and the presence of parasitic DNA in fish is not yet fully understood. Nonetheless, Myxospores with a Myxidium-like morphology, two of which we have shown to be phylogenetically related, have now been reported to develop in three different gill monogeneans, indicating that Myxosporeans are true parasites of monogeneans.
Marianne Koie - One of the best experts on this subject based on the ideXlab platform.
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the marine Myxosporean sigmomyxa sphaerica thelohan 1895 gen n comb n syn myxidium sphaericum from garfish belone belone l uses the polychaete nereis pelagica l as invertebrate host
Parasitology Research, 2012Co-Authors: Egil Karlsbakk, Marianne KoieAbstract:Sigmomyxa sphaerica (Thelohan, 1892) gen. n. (Myxozoa, Myxosporea) with Myxosporean stages in the gall bladder of Belone belone (L.) (Teleostei, Belonidae) uses the polychaete Nereis pelagica L. (Nereidae) from shallow water in the northern Oresund, Denmark, as invertebrate host. The nearly spherical tetractinomyxon-type actinospores of S. sphaerica differ from those of two species of Ellipsomyxa which also use Nereis spp. as invertebrate host. Pansporocysts of S. sphaerica were not seen. S. sphaerica is redescribed on the basis of Myxospore stages from B. belone and actinospores from N. pelagica, and the phylogenetic affinities examined on the basis of ribosomal small subunit gene sequences. S. sphaerica is closest related to Ellipsomyxa spp., and is not congeneric with morphologically similar Myxidium spp. from gadids. This is the fifth elucidated two-host life cycle of a marine myxozoan.
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The marine Myxosporean Sigmomyxa sphaerica (Thélohan, 1895) gen. n., comb. n. (syn. Myxidium sphaericum) from garfish (Belone belone (L.)) uses the polychaete Nereis pelagica L. as invertebrate host
Parasitology Research, 2012Co-Authors: Egil Karlsbakk, Marianne KoieAbstract:Sigmomyxa sphaerica (Thélohan, 1892) gen. n. (Myxozoa, Myxosporea) with Myxosporean stages in the gall bladder of Belone belone (L.) (Teleostei, Belonidae) uses the polychaete Nereis pelagica L. (Nereidae) from shallow water in the northern Øresund, Denmark, as invertebrate host. The nearly spherical tetractinomyxon-type actinospores of S. sphaerica differ from those of two species of Ellipsomyxa which also use Nereis spp. as invertebrate host. Pansporocysts of S. sphaerica were not seen. S. sphaerica is redescribed on the basis of Myxospore stages from B. belone and actinospores from N. pelagica , and the phylogenetic affinities examined on the basis of ribosomal small subunit gene sequences. S. sphaerica is closest related to Ellipsomyxa spp., and is not congeneric with morphologically similar Myxidium spp. from gadids. This is the fifth elucidated two-host life cycle of a marine myxozoan.
Egil Karlsbakk - One of the best experts on this subject based on the ideXlab platform.
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the marine Myxosporean sigmomyxa sphaerica thelohan 1895 gen n comb n syn myxidium sphaericum from garfish belone belone l uses the polychaete nereis pelagica l as invertebrate host
Parasitology Research, 2012Co-Authors: Egil Karlsbakk, Marianne KoieAbstract:Sigmomyxa sphaerica (Thelohan, 1892) gen. n. (Myxozoa, Myxosporea) with Myxosporean stages in the gall bladder of Belone belone (L.) (Teleostei, Belonidae) uses the polychaete Nereis pelagica L. (Nereidae) from shallow water in the northern Oresund, Denmark, as invertebrate host. The nearly spherical tetractinomyxon-type actinospores of S. sphaerica differ from those of two species of Ellipsomyxa which also use Nereis spp. as invertebrate host. Pansporocysts of S. sphaerica were not seen. S. sphaerica is redescribed on the basis of Myxospore stages from B. belone and actinospores from N. pelagica, and the phylogenetic affinities examined on the basis of ribosomal small subunit gene sequences. S. sphaerica is closest related to Ellipsomyxa spp., and is not congeneric with morphologically similar Myxidium spp. from gadids. This is the fifth elucidated two-host life cycle of a marine myxozoan.
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The marine Myxosporean Sigmomyxa sphaerica (Thélohan, 1895) gen. n., comb. n. (syn. Myxidium sphaericum) from garfish (Belone belone (L.)) uses the polychaete Nereis pelagica L. as invertebrate host
Parasitology Research, 2012Co-Authors: Egil Karlsbakk, Marianne KoieAbstract:Sigmomyxa sphaerica (Thélohan, 1892) gen. n. (Myxozoa, Myxosporea) with Myxosporean stages in the gall bladder of Belone belone (L.) (Teleostei, Belonidae) uses the polychaete Nereis pelagica L. (Nereidae) from shallow water in the northern Øresund, Denmark, as invertebrate host. The nearly spherical tetractinomyxon-type actinospores of S. sphaerica differ from those of two species of Ellipsomyxa which also use Nereis spp. as invertebrate host. Pansporocysts of S. sphaerica were not seen. S. sphaerica is redescribed on the basis of Myxospore stages from B. belone and actinospores from N. pelagica , and the phylogenetic affinities examined on the basis of ribosomal small subunit gene sequences. S. sphaerica is closest related to Ellipsomyxa spp., and is not congeneric with morphologically similar Myxidium spp. from gadids. This is the fifth elucidated two-host life cycle of a marine myxozoan.
Hiroshi Sato - One of the best experts on this subject based on the ideXlab platform.
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First report of three multivalvulid species (Cnidaria: Myxozoa: Myxosporea) in commercial fishes from Java Sea, Indonesia, with records of Unicapsula pyramidata and two new Kudoa spp.
Parasitology Research, 2021Co-Authors: Muchammad Yunus, Ken Inoue, Lita Rakhma Yustinasari, Diana Natalia, Subarna Ghosh, Kaishi Sakuma, Hiroshi SatoAbstract:Commercial marine fishes caught locally in East Java, Indonesia, were examined for multivalvulid Myxosporeans (Cnidaria: Myxozoa: Myxosporea). Plasmodia of Unicapsula pyramidata were detected in the trunk muscle of two fork-tailed threadfin breams ( Nemipterus furcosus ). Genetic comparisons of this sample to those collected in the Australian Coral Sea and South China Sea showed few nucleotide substitutions in the small subunit and large subunit ribosomal RNA gene (rDNA) with the species isolated in the Australian Coral Sea and South China Sea. Pseudocysts of two new Kudoa spp. with four shell valves and polar capsules were found in the trunk muscle of two shrimp scads Alepes djedaba and two flathead grey mullets Mugil cephalus . Kudoa javaensis n. sp. Myxospores isolated from the shrimp scad were 5.1–7.2 (mean 6.2) μm thick, 6.2–7.9 (7.3) μm wide, and 4.6–6.3 (5.4) μm long, with polar capsules 1.9–2.5 (2.2) μm long and 1.1–1.4 (1.3) μm wide ( n = 15). Kudoa surabayaensis n. sp. Myxospores isolated from the flathead grey mullet were 5.8–6.7 (6.3) μm thick, 6.4–7.6 (6.9) μm wide, and 4.6–5.0 (4.7) μm long, with polar capsules 1.8–2.4 (2.1) μm long and 0.9–1.3 (1.1) μm wide ( n = 25). These two Kudoa spp. showed critical differences in spore shapes (semiquadrate with unequal shell valves vs. equal shell valves), and absence vs. presence of uplifted shell valve termini. Nucleotide sequencing of rDNA supported the morphological differentiation of these two species. Furthermore, these two isolates were morphologically and phylogenetically distinct from any recorded Kudoa spp.
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identification of four new kudoa spp myxozoa Myxosporea multivalvulida in commercial fishes collected from south china sea atlantic ocean and bering sea by integrated taxonomic approach
Parasitology Research, 2020Co-Authors: Ken Inoue, Jinyong Zhang, Hiroshi Sato, Shuhei TanakaAbstract:Members of the Myxosporean genus Kudoa are defined as having a Myxospore with four or more shell valves (SVs) and a corresponding number of polar capsules (PCs). Here, we employed integrated taxonomic approaches to four kudoid isolates from Acentrogobius chlorostigmatoides and Konosirus punctatus from the South China Sea, off Guangdong, Pentanemus quinquarius from the Southeast Atlantic Ocean, off West African coast, and Atheresthes stomias from the Bering Sea, off Alaska, and concluded that all these kudoids were novel species, named Kudoa acentrogobia n. sp., Kudoa guangdongensis n. sp., Kudoa iidae n. sp., and Kudoa aburakarei n. sp., respectively. Kudoa guangdongensis n. sp., forming pseudocysts in the trunk muscle myofibers of K. punctatus, had large-sized tripod Myxospores with three wing-like SV extensions and three PCs (one prominent PC and two rudimentary PCs). Phylogenetic analyses based on the 18S and 28S ribosomal RNA gene (rDNA) demonstrated its affinity to the genus Kudoa, not to Unicapsula characterized by a Myxospore with one prominent PC and two rudimentary PCs, suggesting the atypical nature of this new species in the context of Myxospore morphology. Three other kudoid isolates had four SVs and PCs in a semi-quadrated, ray-like, or cruciform Myxospore, respectively, forming pseudocysts in the trunk muscle myofibers. Kudoa iidae n. sp. forming pseudocysts in the muscles of P. quinquarius from Southeast Atlantic Ocean had unique Myxospores with ray-like form, showing close morphological resemblance to Kudoa rayformis, which were recorded from the muscle of Scomberomorus sierra from the Pacific Ocean off Panama. These two species had a phylogenetic relationship of morphological convergence, evolving separately in different sea areas. It is fairly difficult to differentiate K. acentrogobia n. sp. and K. aburakarei n. sp., prevalent in their host fishes, from kudoid species with similar Myxospore morphology (e.g., Kudoa nova and Kudoa thyrsites, respectively), but distinct in phylogeny from known Kudoa spp. Combined taxonomic identification of multivalvulid Myxosporeans based on both morphological criteria of isolated myxozoans and their molecular characterization could disclose their real biodiversity and phylogeny.
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phylogenetic characterisation of seven unicapsula spp myxozoa Myxosporea multivalvulida from commercial fish in southern china and japan
Parasitology, 2020Co-Authors: Souhei Tamemasa, Jinyong Zhang, Hiroshi SatoAbstract:The myxozoan genus Unicapsula Davis, 1924 (Myxosporea: Multivalvulida: Trilosporidae) is characterized as having one functional polar capsule (PC) and two rudimentary PCs in a three-valved Myxospore. The plasmodia of Unicapsula spp. grow either in the myofibres or in the gills, oesophageal walls and urinary organs of marine fish. Few studies have investigated the taxonomy of Unicapsula spp. including the type species Unicapsula muscularis. Accordingly, the taxonomy of the genus was explored in the present study by using 15 new isolates of seven Unicapsula spp. (U. muscularis, U. galeata, U. andersenae, U. pyramidata, U. pflugfelderi, and two new species) that had formed pseudocysts in the trunk myofibres of commercial fish collected in southern China and Japan from November 2015 to January 2019. Two new species Unicapsula trigona n. sp., and Unicapsula motomurai n. sp. exhibited unique Myxospore morphologies (semi-triangular and spherical Myxospores, respectively) and 18S and 28S rDNA sequences that were distinct from those of the other Unicapsula spp. Phylogenetic analysis of the 18S and 28S rDNA sequences confirmed the monophyletic status of Unicapsula.
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Morphological and genetic characterization of Kudoa whippsi (Myxosporea: Multivalvulida) from Cheilodactylus zonatus in the western Pacific Ocean off Japan, and two new Kudoa spp. (K. akihitoi n. sp. and K. empressmichikoae n. sp.) from Acanthogobius
Parasitology Research, 2017Co-Authors: Akihiro Kasai, Aogu Setsuda, Hiroshi SatoAbstract:Molecular genetic characterization using the ribosomal RNA (rDNA) gene accrues a wealth of knowledge regarding the true nature of species diversity of Kudoa Meglitsch, 1947 (Myxozoa: Myxosporea: Multivalvulida) and the biogeographical relationships of isolates from different host fish and sea areas. In the present study, we characterized morphologically and genetically three Kudoa spp. with four shell valves and polar capsules (SV/PC), forming pseudocysts in the myofiber of trunk muscles of Cheilodactylus zonatus or Acanthogobius hasta in the natural seawater around Japan. Myxospores from C. zonatus fished in the western Pacific Ocean off Kochi, Japan, were unequal quadrangular pyramids with one large and three smaller SV/PC, morphologically closest to Kudoa whippsi recorded in various pomacentrid and apogonid fish from the Australian Coral Sea. The 18S and 28S rDNA nucleotide sequences of the Japanese isolate were highly similar to some Australian K. whippsi isolates, but also displayed less similarity to other K. whippsi isolates from the same sea mainly due to instability of nucleotides at certain base positions and/or segments of different isolates. All the K. whippsi isolates including the present Japanese isolate, however, were distinct from Kudoa gunterae , K. whippsi ’s closest kudoid species in morphology, molecular phylogeny, and biogeography. Our detection of K. whippsi from C. zonatus in the natural seawater around Japan is a new host and geographical record. Kudoid Myxospores from A. hasta from the Sea of Ariake, a deep bay of the western part of Japan, exhibited two morphotypes, one resembling K. whippsi and the other Kudoa quadricornis with distinct posteriolateral SV projections. However, rDNA nucleotide sequencing revealed that these two Kudoa spp. were distinct from any known congeners; thus, Kudoa akihitoi n. sp. and Kudoa empressmichikoae n. sp. were erected. The morphological differentiation of K. akihitoi n. sp. from multiple Kudoa spp. with scalene stellate Myxospores containing one large and three smaller SV/PC was difficult, whereas K. empressmichikoae n. sp. with spherical spore bodies extending small posteriolateral SV projections was distinct from known congeners with similar but elongated spore bodies and PC, i.e., K. quadricornis and Kudoa paraquadricornis , found in the trunk muscle of carangid fish from the Australian Coral Sea.
