Fine structure and Molecular Phylogenetic Position of Two Marine Gregarines, Selenidium pygospionis sp. n. and S. pherusae sp. n., with Notes on the Phylogeny of Archigregarinida (Apicomplexa)
Language English Country Germany Media print-electronic
Document type Journal Article, Research Support, Non-U.S. Gov't
PubMed
30453272
DOI
10.1016/j.protis.2018.06.004
PII: S1434-4610(18)30066-X
Knihovny.cz E-resources
- Keywords
- 18S rDNA, 28S rDNA, Unicellular parasites, molecular phylogeny., polychaetes, ultrastructure,
- MeSH
- Apicomplexa classification genetics isolation & purification ultrastructure MeSH
- Microscopy, Electron MeSH
- Phylogeny * MeSH
- Locomotion MeSH
- Microscopy MeSH
- Polychaeta parasitology MeSH
- DNA, Protozoan chemistry genetics MeSH
- DNA, Ribosomal chemistry genetics MeSH
- RNA, Ribosomal, 18S genetics MeSH
- RNA, Ribosomal, 28S genetics MeSH
- RNA, Ribosomal, 5.8S genetics MeSH
- Sequence Analysis, DNA MeSH
- Cluster Analysis MeSH
- Aquatic Organisms classification genetics isolation & purification ultrastructure MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- DNA, Protozoan MeSH
- DNA, Ribosomal MeSH
- RNA, Ribosomal, 18S MeSH
- RNA, Ribosomal, 28S MeSH
- RNA, Ribosomal, 5.8S MeSH
Archigregarines are a key group for understanding the early evolution of Apicomplexa. Here we report morphological, ultrastructural, and molecular phylogenetic evidence from two archigregarine species: Selenidium pygospionis sp. n. and S. pherusae sp. n. They exhibited typical features of archigregarines. Additionally, an axial row of vacuoles of a presumably nutrient distribution system was revealed in S. pygospionis. Intracellular stages of S. pygospionis found in the host intestinal epithelium may point to the initial intracellular localization in the course of parasite development. Available archigregarine SSU (18S) rDNA sequences formed four major lineages fitting the taxonomical affiliations of their hosts, but not the morphological or biological features used for the taxonomical revision by Levine (1971). Consequently, the genus Selenidioides Levine, 1971 should be abolished. The branching order of these lineages was unresolved; topology tests rejected neither para- nor monophyly of archigregarines. We provided phylogenies based on LSU (28S) rDNA and near-complete ribosomal operon (concatenated SSU, 5.8S, LSU rDNAs) sequences including S. pygospionis sequences. Although being preliminary, they nevertheless revealed the monophyly of gregarines previously challenged by many molecular phylogenetic studies. Despite their molecular-phylogenetic heterogeneity, archigregarines exhibit an extremely conservative plesiomorphic structure; their ultrastructural key features appear to be symplesiomorphies rather than synapomorphies.
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