Molecular Phylogeny of the Cyrtophorid Ciliates (Protozoa, Ciliophora, Phyllopharyngea)

Gao, Shan; Huang, Jie; Li, Jiamei; Song, Weibo

doi:10.1371/journal.pone.0033198

Cited by 36 publications

(49 citation statements)

References 23 publications

(36 reference statements)

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“…see Fig. 2 in Gao et al, 2012). For this reason, in the present study collection of a Chilodochona sp.…”

Section: Introductionmentioning

confidence: 71%

“…2). As discovered by others (Gao et al, 2012;Qu et al, 2015;Zhao, et al, 2014), the orders Chlamydodontida and Dysteriida, as defined by Lynn (2008), are not monophyletic. The best ML tree placed the genus Trochochilodon (family Plesiotrichopidae; Lynn, 2008) basal to the dysteriid radiation.…”

Section: Molecular Characterization and Phylogenetic Analysesmentioning

confidence: 88%

“…and Isochona sp. Recent molecular genetic research has confirmed the genetic identities of Chlamydodon, Dysteria, Acineta and Ephelota to other species assigned to these genera (unpublished data; Gao et al, 2012;Qu et al, 2015;Zhao et al, 2014). However, there has been some skepticism about the validity of the sequence from Isochona sp.…”

Section: Introductionmentioning

confidence: 92%

“…Subsequent reports have added to the taxonomic sampling of the dysteriids, and now place the Isochona sp. SSUrRNA gene sequence basal to the family Hartmannulidae (Gao et al, 2012;Pan et al, 2012). Gao et al (2012) speculated that the SSUrRNA gene sequence attributed to Isochona sp.…”

Section: Phylogeny Of the Chonotrichiamentioning

confidence: 99%

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The small subunit rRNA gene sequence of the chonotrich Chilodochona carcini Jankowski, 1973 confirms chonotrichs as a dysteriid-derived clade (Phyllopharyngea, Ciliophora)

Lynn

2016

International Journal of Systematic and Evolutionary Microbiology

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The chonotrichs are sessile ciliated protozoa that are ectosymbiotic on the body parts of a variety of crustaceans. They have long been considered a separate group because their sessile habit has resulted in the evolution of a very divergent body form and reproductive strategy compared to free-living ciliates. In the mid-20th Century, the free-living dysteriid cyrtophorian ciliates were proposed as a potential sister clade because the chonotrich bud or daughter cell showed similarities during division morphogenesis (i.e. ontogeny) to these free-living dysteriids. A single small subunit (SSU) rRNA gene sequence is available for the chonotrich Isochona sp. However, its authenticity has recently been questioned, and the placement of this sequence within the dysteriid clade has added to this controversy. In this report, the SSUrRNA gene sequence of the chonotrich Chilodochona carcini, ectosymbiotic on the green crab Carcinus maenas, is provided. Topology testing of the SSUrRNA gene phylogeny, constructed by Bayesian Inference, robustly supports the sister-group relationship of Isochona sp. and Chilodochona carcini, the monophyly of these two chonotrichs, and the divergence of the chonotrich clade within the dysteriid clade. INTRODUCTIONThe chonotrichs, which are sessile symbionts, typically on the mouthparts of crustaceans, have long been recognized as a group of ciliates, although their position within the phylum was not stable until the late 20th Century (Corliss, 1979). Like the sessile suctorians and peritrichs, chonotrichs were separated out from other more motile groups at a high taxonomic rank, primarily because of their sessile nature and the unusual morphology associated with their sessility. Guilcher (1951) carefully studied the morphology of the dispersive/divisional stage of the chonotrichs, the bud or swarmer, and recognized homologies with free-living cyrtophorian ciliates, a conclusion confirmed by, among others, Dobroza nska-Kaczanowska (1963). Grain & Batisse (1974) examined the cortical microtubular components of Chilodochona and found strong similiarities to the cortical components of free-living cyrtophorians, and Fahrni (1982) provided similar data for the cortex of Spirochona gemmipara. These observations strengthened further the hypothesis that the chonotrichs arose from a free-swimming cyrtophorian, perhaps a dysteriid-like ancestor. Ultrastructural examination of the attachment apparatus of chonotrichs also showed significant similarities to the attachment apparatus of dysteriid ciliates (Fahrni 1984;Faur e-Fremiet et al., 1968; Faur e-Fremiet et al., 1956). Snoeyenbos-West et al. (2004) sequenced the small subunit (SSU) rRNA genes of several phyllopharyngean ciliates, including a species of the chonotrich genus Isochona. The Isochona gene sequence robustly clustered within the cyrtophorian clade, sister to the genes of Dysteria species. While Snoeyenbos-West et al. (2004) provided photographic evidence for their identification of the free-living cyrtophorians, Chlamydodon and Dysteria, an...

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“…see Fig. 2 in Gao et al, 2012). For this reason, in the present study collection of a Chilodochona sp.…”

Section: Introductionmentioning

confidence: 71%

Section: Molecular Characterization and Phylogenetic Analysesmentioning

confidence: 88%

Section: Introductionmentioning

confidence: 92%

Section: Phylogeny Of the Chonotrichiamentioning

confidence: 99%

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The small subunit rRNA gene sequence of the chonotrich Chilodochona carcini Jankowski, 1973 confirms chonotrichs as a dysteriid-derived clade (Phyllopharyngea, Ciliophora)

Lynn

2016

International Journal of Systematic and Evolutionary Microbiology

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“…Three such examples are classes Nassophorea, Phyllopharyngea and Prostomatea, which could be crucial taxa in understanding the evolution of phenotypes (e.g. oral ciliation and kinetid fiber systems) and the systematics of the subphylum Intramacronucleata (Gao et al, 2012;Gong et al, 2009b;Lynn, 2008;Zhang et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Further insights into the phylogeny of two ciliate classes Nassophorea and Prostomatea (Protista, Ciliophora)

Zhang

Fan

et al. 2014

Molecular Phylogenetics and Evolution

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a b s t r a c tThe Nassophorea and Prostomatea are two of the key classes in understanding the morphological diversification and higher classification of the phylum Ciliophora. However, their phylogenetic relationships with other ciliate groups within the subphylum Intramacronucleata remain elusive. In this study, we investigated the small and large subunit (SSU and LSU) rRNA gene-based phylogeny of these groups with sequences of additional taxa including several key species. The results show that: (1) the class Nassophorea remains polyphyletic, with the microthoracids clustering with the Phyllopharyngea, whereas the nassulids represent a basal group of the CONthreeP superclade in the SSU tree; (2) the Prostomatea is not depicted as a monophyletic group in phylogenetic trees, and the monophyly of this class is marginally rejected by statistical tree topology tests; (3) the nassulid genus Parafurgasonia is more closely related to the family Colpodidiidae than to Furgasonia; (4) Paranassula, which was previously thought to be a nassulid, is phylogenetically related to the oligohymenophorean peniculids in both the SSU and LSU trees; (5) the microthoracid genus Discotricha does not group with the other microthoracids in either SSU or LSU trees; (6) the family Plagiocampidae is closely related to the prostome parasite Cryptocaryon irritans and to the family Urotrichidae in the order Prorodontida; and (7) the family Placidae, represented by Placus salinus, is sister to the family Holophryidae in the order Prorodontida. Based on the present data, we consider the genus Discotricha to be an unclassified taxon within the CONthreeP. We also propose resurrecting the order Paranassulida and classifying it within the subclass Peniculia, class Oligohymenophorea. Primary and secondary structure signatures for higher taxa within Phyllopharyngea and Nassophorea are supplied.

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Variability in Secondary Structure of 18S Ribosomal RNA as Topological Marker for Identification of Paramecium species

Shakoori

Tasneem

Al‐Ghanim

et al. 2014

J of Cellular Biochemistry

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Besides cytological and molecular applications, Paramecium is being used in water quality assessment and for determination of saprobic levels. An unambiguous identification of these unicellular eukaryotes is not only essential, but its ecological diversity must also be explored in the local environment. 18SrRNA genes of all the strains of Paramecium species isolated from waste water were amplified, cloned and sequenced. Phylogenetic comparison of the nucleotide sequences of these strains with 23 closely related Paramecium species from GenBank Database enabled identification of Paramecium multimicronucleatum and Paramecium jenningsi. Some isolates did not show significant close association with other Paramecium species, and because of their unique position in the phylogenetic tree, they were considered new to the field. In the present report, these isolates are being designated as Paramecium caudatum pakistanicus. In this article, secondary structure of 18SrRNA has also been analyzed as an additional and perhaps more reliable topological marker for species discrimination and for determining possible phylogenetic relationship between the ciliate species. On the basis of comparison of secondary structure of 18SrRNA of various isolated Paramacium strains, and among Paramecium caudatum pakistanicus, Tetrahymena thermophila, Drosophila melanogaster, and Homo sapiens, it can be deduced that variable regions are more helpful in differentiating the species at interspecific level rather than at intraspecific level. It was concluded that V3 was the least variable region in all the organisms, V2 and V7 were the longest expansion segments of D. melanogaster and there was continuous mutational bias towards G.C base pairing in H. sapiens.

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Molecular Phylogeny of the Cyrtophorid Ciliates (Protozoa, Ciliophora, Phyllopharyngea)

Cited by 36 publications

References 23 publications

The small subunit rRNA gene sequence of the chonotrich Chilodochona carcini Jankowski, 1973 confirms chonotrichs as a dysteriid-derived clade (Phyllopharyngea, Ciliophora)

The small subunit rRNA gene sequence of the chonotrich Chilodochona carcini Jankowski, 1973 confirms chonotrichs as a dysteriid-derived clade (Phyllopharyngea, Ciliophora)

Further insights into the phylogeny of two ciliate classes Nassophorea and Prostomatea (Protista, Ciliophora)

Variability in Secondary Structure of 18S Ribosomal RNA as Topological Marker for Identification of Paramecium species

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