Techniques and tools for species identification in ciliates: a review (original) (raw)
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Microbial Ecology, 2003
Ciliate protozoa are important members of microbial communities in which they play specific ecological roles. The determination of single species distribution is fundamental for food web analysis, but species recognition, which is mainly based on morphological characters, is often difficult between closely related species. The use of species-specific, purposely designed, fluorescently labeled probes for in situ hybridization is here presented as an easy and fast identification method for three closely related species belonging to the widespread genus Euplotes, namely E. crassus, E. vannus, and E. minuta, that in spite of their remarkable morphological similarity have significant metabolic and ecological differences. These three species can be detected simultaneously, provided the probes employed are bound to different fluorescent dyes: in this way their relative abundance and their population dynamics in the natural environment can be evaluated. As more ciliate sequences become available in databases, species-specific probes can be designed for other ciliates, thus rendering the application of the method of more general importance. The probes used in this study may also provide a tool to prevent erroneous species identification in future studies.
Background: Heterotrichous ciliates are common members of microeukaryote communities which play important roles in both the transfer of material and the flow of energy in aquatic food webs. This group has been known for over two centuries due to their large body size and cosmopolitan distribution. Nevertheless, species identification and phylogenetic relationships of heterotrichs remain challenging due to the lack of accurate morphological information and insufficient molecular data.Results: The morphology and phylogeny of two heterotrichous ciliates, namely Gruberia foissneri spec. nov. and Linostomella vorticella (Ehrenberg, 1833) Aescht in Foissner et al., 1999, were studied using rigorous methods (living morphology, stained preparations, and small subunit rDNA sequence data). Gruberia foissneri spec. nov. is morphologically very similar to G. uninucleata Kahl, 1932, however, it can be distinguished from the latter by having more ciliary rows (about 32 vs. about 20) and macronucl...
2020
Background Heterotrichous ciliates are common members of microeukaryote communities which play important roles in the transfer of material and energy flow in aquatic food webs. This group has been known over two centuries due to their large body size and cosmopolitan distribution. Nevertheless, species identification and phylogenetic relationships of heterotrichs remain challenging due to the lack of accurate morphological information and insufficient molecular data. Results The morphology and phylogeny of two poorly known heterotrichous ciliates, Gruberia uninucleata Kahl, 1932 and Linostomella vorticella (Ehrenberg, 1833) Aescht in Foissner et al. , 1999, were investigated based on their living morphology, infraciliature, and small subunit (SSU) rDNA sequence data. Based on a combination of previous and present studies, detailed morphometric data and the improved diagnoses of both species are supplied here. In addition, molecular data of the two species are reported for the first ...
Biodiversity at the Microbial Level: The Number of Free-Living Ciliates in the Biosphere
The Quarterly Review of Biology, 1996
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Zoological Journal of the Linnean Society, 2016
The morphology and phylogeny of three heterotrich ciliates, Anigsteinia clarissima (Anigstein, 1912) Isquith, 1968, Blepharisma penardi sp. nov., and Blepharisma undulans Stein, 1867, were investigated based on living morphology, infraciliature, and small subunit (SSU) rDNA sequence data. The new species B. penardi sp. nov. is recognized by the following combination of characters: size about 150-180 × 45-55 μm in vivo, cell colour variable from colourless to pale pink to dark brownish; peristome extending to middle of body; 36-63 adoral membranelles; 24-34 somatic kineties; single macronucleus; cortical granules tiny and colourless; freshwater habitat. Anigsteinia clarissima and B. undulans are both reported from China for the first time and are redescribed based on a combination of previous descriptions and new data from the Chinese populations. Phylogenetic analyses based on SSU rDNA sequence data show that B. penardi sp. nov. and B. undulans are both located within a clade comprising only congeners, thus supporting the monophyly of the genus Blepharisma. Anigsteinia clarissima clusters with its only congener forming a clade that is sister to the Spirostomum assemblage. Both the morphological and the molecular data support the placement of Anigsteinia in the family Spirostomidae.
Zoological Journal of the Linnean Society, 2016
The morphology and phylogeny of three heterotrich ciliates, Anigsteinia clarissima (Anigstein, 1912) Isquith, 1968, Blepharisma penardi sp. nov., and Blepharisma undulans Stein, 1867, were investigated based on living morphology, infraciliature, and small subunit (SSU) rDNA sequence data. The new species B. penardi sp. nov. is recognized by the following combination of characters: size about 150-180 × 45-55 μm in vivo, cell colour variable from colourless to pale pink to dark brownish; peristome extending to middle of body; 36-63 adoral membranelles; 24-34 somatic kineties; single macronucleus; cortical granules tiny and colourless; freshwater habitat. Anigsteinia clarissima and B. undulans are both reported from China for the first time and are redescribed based on a combination of previous descriptions and new data from the Chinese populations. Phylogenetic analyses based on SSU rDNA sequence data show that B. penardi sp. nov. and B. undulans are both located within a clade comprising only congeners, thus supporting the monophyly of the genus Blepharisma. Anigsteinia clarissima clusters with its only congener forming a clade that is sister to the Spirostomum assemblage. Both the morphological and the molecular data support the placement of Anigsteinia in the family Spirostomidae.
Diversity of Free-Living Morphospecies in the Ciliate Genus< i> Metopus
Archiv für Protistenkunde, 1995
This is a taxonomic revision of anaerobic free-living ciliates in the genus Metopus. It includes a rationalization of all nominal species described in the literature, and the allocation of the survivors to "morphospecies". The revision is based on examination of cultured species together with an exhaustive comparison of the published descriptions of nominal species. All free-living Metopus can be allocated to one of five general morphological types. Each type contains several morphospecies (and their synonyms), each with conservative features. The seventy-six nominal species of Metopus are reduced to 22 morphospecies, and M. nivaaensis n. sp. is described.
Molecular Phylogeny of Tintinnid Ciliates (Tintinnida, Ciliophora)
2012
We investigated the phylogeny of tintinnids (Ciliophora, Tintinnida) with 62 new SSU-rDNA sequences from single cells of 32 marine and freshwater species in 20 genera, including the first SSU-rDNA sequences for Amphorides, Climacocylis, Codonaria, Cyttarocylis, Parundella, Petalotricha, Undella and Xystonella, and 23 ITS sequences of 17 species in 15 genera. SSU-rDNA phylogenies suggested a basal position for Eutintinnus, distant to other Tintinnidae. We propose Eutintinnidae fam. nov. for this divergent genus, keeping the family Tintinnidae for Amphorellopsis, Amphorides and Steenstrupiella. Tintinnopsis species branched in at least two separate groups and, unexpectedly, Climacocylis branched among Tintinnopsis sensu stricto species. Tintinnopsis does not belong to the family Codonellidae, which is restricted to Codonella, Codonaria, and also Dictyocysta (formerly in the family Dictyocystidae). The oceanic genus Undella branched close to an undescribed freshwater species. Metacylis, Rhabdonella and Cyttarocylis formed a well supported clade with several Tintinnopsis species at a basal position. Petalotricha ampulla and Cyttarocylis cassis SSU-rDNA and ITS sequences were identical or almost identical. Therefore, we propose Cyttarocylis ampulla comb. nov. for them. Intensive use of single-cell isolation and sequencing revealed unexpected complexity in the evolutionary history of these relatively well-studied ciliates. Notably, the diversity of freshwater forms suggests multiple marine-freshwater invasions.
Diversity of Free-Living Morphospecies in the Ciliate Genus Metopus
Archiv für Protistenkunde, 1995
This is a taxonomic revision of anaerobic free-living ciliates in the genus Metopus. It includes a rationalization of all nominal species described in the literature, and the allocation of the survivors to "morphospecies". The revision is based on examination of cultured species together with an exhaustive comparison of the published descriptions of nominal species. All free-living Metopus can be allocated to one of five general morphological types. Each type contains several morphospecies (and their synonyms), each with conservative features. The seventy-six nominal species of Metopus are reduced to 22 morphospecies, and M. nivaaensis n. sp. is described.