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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.
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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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.
Chris T. Mcallister - One of the best experts on this subject based on the ideXlab platform.
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Morphological and Molecular Characterisation of Myxidium kudoi Meglitsch, 1937 from the Blue Catfish Ictalurus furcatus, Valenciennes in Oklahoma, USA
Acta Parasitologica, 2020Co-Authors: Ethan T. Woodyard, Thomas G. Rosser, Chris T. McallisterAbstract:Background Myxidium kudoi Meglitsch, 1937 has been described from the type host, blue catfish Ictalurus furcatus , with no additional host records or molecular data available for this species. Purpose To provide molecular data and a novel host locality for this species and carry out phylogenetic analyses to infer the evolutionary relationship of the species to other members of the family Myxidiidae for which DNA sequence data is available. Methods These data were collected using myxospores from the gallbladder of a blue catfish, Ictalurus furcatus collected from Lake Texoma, Oklahoma, USA. Myxospores were morphologically consistent with the only other account of this species and not any other Myxidium species described from siluriform fishes. Results Myxospores were oblong with rounded ends and were 10.8–12.6 (11.6 ± 0.5) µm in length and 4.7–6.6 (5.7 ± 0.5) µm in width. Polar capsules were subspherical and 2.7–3.9 (3.4 ± 0.3) µm in length and 2.4–3.5 (3.1 ± 0.3) µm in diameter, with each capsule containing a polar filament with 3–4 coils. Molecular data consisted of a 2918-bp sequence of the partial 18S, complete ITS1, 5.8S, ITS2, and partial 28S ribosomal rRNA regions as well as a 2455-bp sequence of partial 28S ribosomal RNA. The partial 18S and 28S data was used in a concatenated Bayesian phylogenetic analysis to further infer the evolutionary relationships of the Myxidiidae. Additionally, the partial 18S data was used in a separate phylogenetic analysis. Conclusions The present work reports novel morphological and molecular data for Myxidium kudoi as well as a novel locality of occurrence for this species. In concatenated phylogenetic analysis using 18S and 28S data and other molecular data from Myxozoa, M. kudoi grouped with other freshwater Myxidiidae. In the single-locus, 18S analysis, M. kudoi grouped with Myxidium rhodei from Rutilus rutilus and Myxidium amazonense from Corydoras melini , the only other Myxidium species of catfish for which molecular data are available.
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morphological and molecular characterisation of Myxidium kudoi meglitsch 1937 from the blue catfish ictalurus furcatus valenciennes in oklahoma usa
Acta Parasitologica, 2020Co-Authors: Ethan T. Woodyard, Thomas G. Rosser, Chris T. McallisterAbstract:Background Myxidium kudoi Meglitsch, 1937 has been described from the type host, blue catfish Ictalurus furcatus, with no additional host records or molecular data available for this species.
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a new host and geographic record for Myxidium lesminteri protozoa myxosporea from tomopterna cryptotis amphibia ranidae in namibia south west africa
Journal of the Helminthological Society of Washington, 1996Co-Authors: Chris T. Mcallister, Paul S FreedAbstract:A new host and geographic distribution record is reported for the myxosporean, Myxidium les- minteri Delvinquier, Markus, and Passmore, 1992, from the stripe-burrowing frog, Tomopterna cryptotis (Ran- idae) in Namibia, South-West Africa. One of 4 (25%) T. cryptotis was found to be harboring trophozoites and spores of M. lesminteri in the gall bladder. The species was originally described from a congeneric ran- id, Tomopterna krugerensis, and also from Bufo gar- mani (Bufonidae) and Heleophryne natalensis (Heleo- phrynidae) in South Africa.
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new host records for Myxidium serotinum protozoa myxosporea from north american amphibians
Journal of Parasitology, 1995Co-Authors: Chris T. Mcallister, Stanley E TrauthAbstract:Three hundred twenty-five amphibians (80 salamanders, 245 frogs and toads) from Arkansas and Texas, representing 28 species within 9 families (Ambystomatidae, Plethodontidae, Salamandridae, Sirenidae, Bufonidae, Hylidae, Leptodactylidae, Microhylidae, Ranidae) were examined for gall bladder myxosporeans. Of these, 32 (10%) were found to harbor Myxidium serotinum Kudo and Sprague, 1940, including 3 (4%) of the salamanders and 29 (12%) of the frogs and toads. This report documents 6 new host records for M. serotinum in Ambystoma opacum, Bufo americanus charlesmithi, Bufo speciosus, Acris crepitans blanchardi, Gastrophryne olivacea, and Pseudacris streckeri illinoensis. In addition, the Great Plains narrowmouth toad G. olivacea represents the first microhylid host of Myxidium spp. worldwide.
Georges Bouix - One of the best experts on this subject based on the ideXlab platform.
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ultrastructural data on the sporogenesis of Myxidium giardi cepede 1906 myxozoa myxosporidia parasite of anguilla anguilla teleostea
European Journal of Protistology, 1993Co-Authors: Hassan M Benajiba, Adam Marques, Georges BouixAbstract:Summary Ultrastructural study of Myxidium giardi showed that pluricellularity is maintained by the formation of septate desmosomes. The polar capsule is formed from helicoidal depositions of banded material in the initial vacuole. This process makes possible not only the formation of the rigid capsular body but also of the flexible polar filament which is evaginable and reversed in the capsule. The special feature of the genus Myxidium is the ornamentation of the valvogenic cells of the spores in the form of longitudinal ribs. An ultrastructural study showed that the morphogenesis of this cell relief in Myxidium giardi involves a special process based on the development of fusiform macrovesicles whose bases are connected to a cytoskeleton formed of special microtubules 14 nm in diameter. The latter seem to determine the future rigidity of the valvar epicyte.
Christina Sommerville - One of the best experts on this subject based on the ideXlab platform.
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Molecular relationships and phylogeny in a community of myxosporeans and actinosporeans based on their 18S rDNA sequences.
International Journal for Parasitology, 2004Co-Authors: Astrid S. Holzer, Christina Sommerville, R. WoottenAbstract:Abstract The community of myxosporeans and actinosporeans inhabiting a typical Scottish highland stream and the outflow area of an adjacent salmon hatchery was analysed on the basis of their 18S rDNA sequences. Nine myxosporeans belonging to the genera Sphaerospora , Chloromyxum , Zschokkella , Myxidium , Hoferellus and Myxobilatus were identified from mature spores in different organs of the fish species present. Twelve actinosporean types belonging to the collective groups of neoactinomyxum, aurantiactinomyxon, raabeia, echinactinomyxon and synactinomyxon were found to be released from oligochaete worms collected from sediments. Twenty of the 21 sequences obtained from these myxozoans are new entries to the myxozoan database, and the genera Chloromyxum , Hoferellus and Myxobilatus were entered for the first time. Study of the molecular relationships between the different taxa and with other myxozoan sequences available showed that the myxosporeans inhabiting the urinary system clearly cluster together, independently of host species or spore morphology. However, the sequences of the two Sphaerospora species encountered show considerable differences from other members of this group and all other freshwater myxosporeans, and they were found to occupy an ancestral marine position. Three actinosporeans, i.e. Neoactinomyxum eiseniellae , Aurantiactinomyxon pavinsis and Raabeia ‘type 3’ were found to represent alternate life cycle stages of Chloromyxum sp., Chloromyxum truttae and Myxidium truttae , respectively (approximately 1400 identical base pairs each). Three other actinosporeans encountered (two echinactinomyxon and one raabeia type) showed over 92% sequence identity with myxosporeans from GenBank™, whereas all other actinosporeans formed a closely related group devoid of any known myxosporeans.
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a comparative study of the myxosporeans Myxidium rhodei leger 1905 and Myxidium pfeifferi auerbach 1908 in roach rutilus rutilus l
Journal of Fish Diseases, 1993Co-Authors: F Athanassopoulou, Christina SommervilleAbstract:. The morphology and dimensions of Myxidium rhodei and M. pfeifferi were studied in roach originating from two different geographic locations (Greece and UK) using both scanning and light microscopy. The measurements and morphology of both mature spores and immature stages (trophozoites and spores) were studied and compared. No differences were observed in the morphology of mature or immature spores of both species when examined under light and SEM. Furthermore, no differences were found in the dimensions of the mature spores of both species in all fish. However, immature spores of both species were found to be smaller but wider than mature ones in all organs and in both habitats. Size differences between the two species were only seen in immature spores, M. rhodei immature spores being always larger than those of M. pfeifferi. When comparing the dimensions of the spores between the two habitats, these were larger and wider in the Greek fish than those in the British fish. The information in this study suggests that, in roach, M. pfeifferi is undistinguishable from M. rhodei and that similar studies should be carried out on the tench, Tinca tinca L., the type host of M. pfeifferi.
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The significance of myxosporean infections in roach, Rutilus rutilus L., in different habitats
Journal of Fish Diseases, 1993Co-Authors: F Athanassopoulou, Christina SommervilleAbstract:. Two Myxobolus species, M. pseudodispar and M. ellipsoides, and two Myxidium species, M. rhodei and M. pfeifferi, were found in roach, Rutilus rutilus L., from three different locations in northern Greece, northern England and Scotland. Their prevalence, distribution in the host and pathology were studied. In the ease of M. rhodei, the pathological changes were quantitatively evaluated by computer-based image analysis, and the results expressed in terms of area and volume of organs affected. The pathology of M. pfeifferi was associated with trophozoites in the bile duets and the infection ranged from mild to severe. In the severe eases, degeneration of duetal mucosa sometimes progressed to focal hepatitis. Myxidium rhodei was found in the kidneys as large cysts containing mature and immature spores (Type A cysts), and less often, in the form of small concentric cysts (Type B) which contained no obvious spores but which were characterized by a marked host response giving the appearance of focal granulomas. Type A cysts were also found in liver and spleen, and Type B cysts in the heart. Trophozoites of M. rhodei were observed in only a few eases and occurred in enlarged renal corpuscles in which the capillary tuft was atrophied and compressed. The pathology of M. rhodei was significant due to the enlargement of glomeruli from four to seven times their normal size and with an estimated increase in volume of 54 to 78 times. In addition to the functional damage to the glomeruli, there was also damage of the surrounding interstitial tissue and tubules as a result of the pressure from these enlarged glomeruli. The two myxobolid species were considered to be mainly specific to the kidney with no serious pathology in this organ, but caused significant pathology in the muscles (M. pseudodispar) and gills (M. ellipsoides).
