<it>Desmozoon lepeophtherii </it>n. gen., n. sp., (Microsporidia: Enterocytozoonidae) infecting the salmon louse <it>Lepeophtheirus salmonis </it>(Copepoda: Caligidae)
<p>Abstract</p> <p>Background</p> <p>A microsporidian was previously reported to infect the crustacean parasite, <it>Lepeophtheirus salmonis </it>(Krøyer, 1837) (Copepoda, Caligidae), on farmed Atlantic salmon (<it>Salmo salar </it>L.) in Scotlan...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
BMC
2009-11-01
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| Series: | Parasites & Vectors |
| Online Access: | http://www.parasitesandvectors.com/content/2/1/58 |
| _version_ | 1811314258119491584 |
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| author | Freeman Mark A Sommerville Christina |
| author_facet | Freeman Mark A Sommerville Christina |
| author_sort | Freeman Mark A |
| collection | DOAJ |
| description | <p>Abstract</p> <p>Background</p> <p>A microsporidian was previously reported to infect the crustacean parasite, <it>Lepeophtheirus salmonis </it>(Krøyer, 1837) (Copepoda, Caligidae), on farmed Atlantic salmon (<it>Salmo salar </it>L.) in Scotland. The microsporidian was shown to be a novel species with a molecular phylogenetic relationship to <it>Nucleospora </it>(Enterocytozoonidae), but the original report did not assign it to a genus or species. Further studies examined the development of the microsporidian in <it>L. salmonis </it>using electron microscopy and re-evaluated the molecular findings using new sequence data available for the group. Here we report a full description for the microsporidian and assign it to a new genus and species.</p> <p>Results</p> <p>The microsporidian infects subcuticular cells that lie on the innermost region of the epidermal tissue layer beneath the cuticle and along the internal haemocoelic divisions. The mature spores are sub-spherical with a single nucleus and an isofilar polar filament with 5-8 turns in a double coil. The entire development is in direct contact with the host cell cytoplasm and is polysporous. During early merogony, a diplokaryotic nuclear arrangement exists which is absent throughout the rest of the developmental cycle. Large merogonial plasmodia form which divide to form single uninucleate sporonts. Sporogonial plasmodia were not observed; instead, binucleate sporonts divide to form two sporoblasts. Prior to final division, there is a precocious development of the polar filament extrusion apparatus which is associated with large electron lucent inclusions (ELIs). Analyses of DNA sequences reveal that the microsporidian is robustly supported in a clade with other members of the Enterocytozoonidae and confirms a close phylogenetic relationship with <it>Nucleospora</it>.</p> <p>Conclusion</p> <p>The ultrastructural findings of the precocious development of the polar filament and the presence of ELIs are consistent with those of the Enterocytozoonidae. However, the confirmed presence of an early diplokaryotic stage and a merogonial plasmodium that divides to yield uninucleate sporonts instead of transforming into a sporogonial syncitium, are features not currently associated with the family. Yet, analyses of DNA sequence data clearly place the microsporidian within the Enterocytozoonidae. Therefore, due to the novelty of the copepod host, the ultrastructural findings and the robust nature of the phylogenetic analyses, a new genus should be created within the Enterocytozoonide; <it>Desmozoon lepeophtherii </it>n. gen. n. sp. is proposed.</p> |
| first_indexed | 2024-04-13T11:09:38Z |
| format | Article |
| id | doaj.art-2a568ca0359445f7bca12222a4c38c96 |
| institution | Directory Open Access Journal |
| issn | 1756-3305 |
| language | English |
| last_indexed | 2024-04-13T11:09:38Z |
| publishDate | 2009-11-01 |
| publisher | BMC |
| record_format | Article |
| series | Parasites & Vectors |
| spelling | doaj.art-2a568ca0359445f7bca12222a4c38c962022-12-22T02:49:10ZengBMCParasites & Vectors1756-33052009-11-01215810.1186/1756-3305-2-58<it>Desmozoon lepeophtherii </it>n. gen., n. sp., (Microsporidia: Enterocytozoonidae) infecting the salmon louse <it>Lepeophtheirus salmonis </it>(Copepoda: Caligidae)Freeman Mark ASommerville Christina<p>Abstract</p> <p>Background</p> <p>A microsporidian was previously reported to infect the crustacean parasite, <it>Lepeophtheirus salmonis </it>(Krøyer, 1837) (Copepoda, Caligidae), on farmed Atlantic salmon (<it>Salmo salar </it>L.) in Scotland. The microsporidian was shown to be a novel species with a molecular phylogenetic relationship to <it>Nucleospora </it>(Enterocytozoonidae), but the original report did not assign it to a genus or species. Further studies examined the development of the microsporidian in <it>L. salmonis </it>using electron microscopy and re-evaluated the molecular findings using new sequence data available for the group. Here we report a full description for the microsporidian and assign it to a new genus and species.</p> <p>Results</p> <p>The microsporidian infects subcuticular cells that lie on the innermost region of the epidermal tissue layer beneath the cuticle and along the internal haemocoelic divisions. The mature spores are sub-spherical with a single nucleus and an isofilar polar filament with 5-8 turns in a double coil. The entire development is in direct contact with the host cell cytoplasm and is polysporous. During early merogony, a diplokaryotic nuclear arrangement exists which is absent throughout the rest of the developmental cycle. Large merogonial plasmodia form which divide to form single uninucleate sporonts. Sporogonial plasmodia were not observed; instead, binucleate sporonts divide to form two sporoblasts. Prior to final division, there is a precocious development of the polar filament extrusion apparatus which is associated with large electron lucent inclusions (ELIs). Analyses of DNA sequences reveal that the microsporidian is robustly supported in a clade with other members of the Enterocytozoonidae and confirms a close phylogenetic relationship with <it>Nucleospora</it>.</p> <p>Conclusion</p> <p>The ultrastructural findings of the precocious development of the polar filament and the presence of ELIs are consistent with those of the Enterocytozoonidae. However, the confirmed presence of an early diplokaryotic stage and a merogonial plasmodium that divides to yield uninucleate sporonts instead of transforming into a sporogonial syncitium, are features not currently associated with the family. Yet, analyses of DNA sequence data clearly place the microsporidian within the Enterocytozoonidae. Therefore, due to the novelty of the copepod host, the ultrastructural findings and the robust nature of the phylogenetic analyses, a new genus should be created within the Enterocytozoonide; <it>Desmozoon lepeophtherii </it>n. gen. n. sp. is proposed.</p>http://www.parasitesandvectors.com/content/2/1/58 |
| spellingShingle | Freeman Mark A Sommerville Christina <it>Desmozoon lepeophtherii </it>n. gen., n. sp., (Microsporidia: Enterocytozoonidae) infecting the salmon louse <it>Lepeophtheirus salmonis </it>(Copepoda: Caligidae) Parasites & Vectors |
| title | <it>Desmozoon lepeophtherii </it>n. gen., n. sp., (Microsporidia: Enterocytozoonidae) infecting the salmon louse <it>Lepeophtheirus salmonis </it>(Copepoda: Caligidae) |
| title_full | <it>Desmozoon lepeophtherii </it>n. gen., n. sp., (Microsporidia: Enterocytozoonidae) infecting the salmon louse <it>Lepeophtheirus salmonis </it>(Copepoda: Caligidae) |
| title_fullStr | <it>Desmozoon lepeophtherii </it>n. gen., n. sp., (Microsporidia: Enterocytozoonidae) infecting the salmon louse <it>Lepeophtheirus salmonis </it>(Copepoda: Caligidae) |
| title_full_unstemmed | <it>Desmozoon lepeophtherii </it>n. gen., n. sp., (Microsporidia: Enterocytozoonidae) infecting the salmon louse <it>Lepeophtheirus salmonis </it>(Copepoda: Caligidae) |
| title_short | <it>Desmozoon lepeophtherii </it>n. gen., n. sp., (Microsporidia: Enterocytozoonidae) infecting the salmon louse <it>Lepeophtheirus salmonis </it>(Copepoda: Caligidae) |
| title_sort | it desmozoon lepeophtherii it n gen n sp microsporidia enterocytozoonidae infecting the salmon louse it lepeophtheirus salmonis it copepoda caligidae |
| url | http://www.parasitesandvectors.com/content/2/1/58 |
| work_keys_str_mv | AT freemanmarka itdesmozoonlepeophtheriiitngennspmicrosporidiaenterocytozoonidaeinfectingthesalmonlouseitlepeophtheirussalmonisitcopepodacaligidae AT sommervillechristina itdesmozoonlepeophtheriiitngennspmicrosporidiaenterocytozoonidaeinfectingthesalmonlouseitlepeophtheirussalmonisitcopepodacaligidae |