Postoral Kineties Research Articles

Morphology and SSU rRNA gene-based phylogeny of three peniculid ciliates (Ciliophora, Oligohymenophorea) from China, including a new Frontonia species

In the present study, a new freshwater peniculid species, Frontonia apoelegans sp. nov., and two other peniculid species, Frontonia atra (Ehrenberg, 1833) Bütschli, 1889 and Stokesia vernalis Wenrich, 1929, were isolated from Lake Weishan wetland, northern China. Their morphology and infraciliature are described based on live observations and silver staining methods. The SSU rRNA gene sequences are also provided. Frontonia apoelegans sp. nov. is recognized by the following combination of characteristics: two contractile vacuoles located right-dorsally, without collecting canals; peniculi 1 and 2 four-rowed, peniculus 3 three-rowed with leftmost row containing only one kinetosome; 62–76 somatic kineties; three ophryokineties; and four or five postoral kineties. We also provide improved diagnoses for Frontonia atra and Stokesia vernalis based on current and previous reports. Comparisons with sequences of morphologically similar species clearly support the validity of the new species. Phylogenetic analyses based on SSU rRNA gene sequence data reveal that Frontonia species with two contractile vacuoles cluster in a single clade, indicating these species may have a common origin. The family Frontoniidae is non-monophyletic whereas the family Stokesiidae remains monophyletic according to our analyses.

Historical Review of Studies on Cyrtophorian Ciliates (Ciliophora, Cyrtophoria) from China.

The subclass Cyrtophoria are a group of morphologically specialized ciliates which mainly inhabit soil, freshwater, brackish water, and marine environments. In this study, we revise more than 50 publications on the taxonomy, phylogeny, and ecology of cyrtophorian ciliates in China since the first publication in 1925, most of which were carried out in coastal areas. The research history can be divided into three periods: the early stage, the Tibet stage, and the molecular stage. To date, 103 morpho-species (147 isolates) have been formally recorded in China, with ciliature patterns described for 82 of them. A species checklist and an illustrated identification key to the genera are provided. A total of 100 small subunit rDNA sequences have been obtained for 74 taxonomic hits (lowest taxonomic rank to species or genus). These sequences are used for the study of molecular phylogeny. Based on these morphological data and molecular phylogeny analyses, we synthesize the understanding of the phylogeny of cyrtophorian ciliates. We hypothesize that the key evolutionary event of cyrtophorian ciliates lies in the separation of the stomatogenesis zone (postoral kineties) from the left kineties, namely, the formation of an independent “sexual organelle”. We, furthermore, briefly summarize the ecological features of cyrtophorian ciliates and provide a comprehensive bibliography of related research from China. Finally, we give an outlook on the future research directions of these taxa.

Study on Analysis of Several Molecular Identification Methods for Ciliates of Colpodea (Protista, Ciliophora)

The application of molecular techniques to accurately identify protozoan species can correct previous misidentifications based on traditional morphological identification. Colpodea ciliates have many toxicological and cytological applications, but their subtle morphological differences and small body size hinder species delineation. Herein, we used Cox I and β-tubulin genes, alongside fluorescence in situ hybridization (FISH), to evaluate each method in delineating Colpodea species. For this analysis, Colpoda harbinensis n. sp., C. reniformis, two populations of C. inflata, Colpoda compare grandis, and five populations of Paracolpoda steinii, from the soil in northeastern China, were used. We determined that (1) the Cox I gene was more suitable than the β-tubulin gene as a molecular marker for defining intra- and interspecific level relationships of Colpoda. (2) FISH probes designed for Colpoda sp., C. inflata, Colpoda compare grandis, and Paracolpoda steinii, provided rapid interspecific differentiation of Colpodea species. (3) Colpoda harbinensis n. sp. was established and mainly characterized by its size in vivo (approximately 80 × 60 μ m ), a reniform body in outline, one macronucleus, its spherical shape, a sometimes nonexistent micronucleus, 11–15 somatic kineties, and five or six postoral kineties. In conclusion, combining oligonucleotide probes, DNA barcoding, and morphology for the first time, we have greatly improved the delineation of Colpodea and confirmed that Cox I gene was a promising DNA barcoding marker for species of Colpodea, and FISH could provide useful morphological information as complementing traditional techniques such as silver carbonate.

Morphology, morphogenesis and phylogeny of Anteglaucoma orientalis n. sp. (Ciliophora, Oligohymenophorea), a freshwater hymenostomatid from northeastern China

A new hymenostomatid ciliate, Anteglaucoma orientalis n. sp., isolated from a freshwater pond in Harbin, northeastern China, was investigated using live observation and silver staining methods. Anteglaucoma orientalis is characterized as follows: size in vivo about 50–60 × 30–35 μm; oval body shape; buccal area occupies about 25% of body length; 28–36 somatic kineties; membranelle 1 having six or seven basal body rows, membranelle 2 five to seven rows, and membranelle 3 three rows; single macronucleus with one micronucleus attached. Morphogenesis of the genus Anteglaucoma is revealed for the first time. The main events during binary fission are as follows: morphogenesis begins with proliferation of kinetosomes in the middle part of postoral kinety 1, and kinetosomes of this primordial field multiply and organize to finally form the paroral membrane and membranelles 1–3 of the opisthe; the parental apparatus in the proter does not take part in the stomatogenetic process. Phylogenetic analyses based on SSU rRNA gene sequences show that Anteglaucoma orientalis n. sp. clusters with the type species, A. harbinensis Pan et al., 2017, with full support.

Morphology and phylogeny of a new soil ciliate, Colpodidium zelihayildizi n. sp. (Ciliophora, Nassophorea, Colpodidiidae), from Van, Turkey

new ciliate species Colpodidium zelihayildizae n. sp., which was discovered in a dry irrigation channel in Van (Turkey), was investigated morphologically using standard live and silver impregnation methods, and its SSU rRNA gene phylogeny was provided. This new species was characterized as follows: body size about 40-60 × 15-20 ?m in vivo, elongated ellipsoidal with flat or slightly concave ventral surface; the buccal cavity slightly below equatorial plane; macronucleus spherical or slightly elliptical, usually located in the last third of the cell; cortex distinctly furrowed in the anterior half; 19-22 somatic kineties, 4 postoral kineties; paroral membrane has 20 dikinetids; 3 nassulid organelles (NOs), with NO1 very close to the left edge of the paroral membrane, which consists of 1 dikinetid pair. Phylogenetic analyses conducted on the SSU rDNA sequences determined that Colpodidium zelihayildizae was clustered with Colpodidium caudatum and formed a clade with Apocolpodidium etoschense and Colpodididae sp.

A huge diversity of metopids (Ciliophora, Armophorea) in soil from the Murray River floodplain, Australia. III. Morphology, ontogenesis and conjugation of Metopus boletus nov. spec., with implications for the phylogeny of the SAL supercluster

The morphology, ontogenesis, conjugation, and phylogenetic position of Metopus boletus nov. spec. were studied using live observation, various silver impregnation methods, scanning electron microscopy, morphometry, and the 18S rRNA gene sequence. The new species is outstanding in having a mushroom-like appearance; a globular to broadly ellipsoid macronucleus in anterior body half; 5–10 elongated caudal cilia; 4–6 dikinetids curved rightwards in the anterior portion of the first postoral kinety; and an adoral zone composed of an average of 28 small polykinetids. Ontogenesis of M. boletus follows the metopid mode and the species-specific vegetative morphology is obtained after division. Its conjugation is temporary, isogamic and the partners unite ventral-to-dorsal, forming strongly arched to almost rod-like pairs, which indicates a heteropolar arrangement. There are only two maturation divisions and a single synkaryon division in exconjugants. The conjugation data corroborate a sister group relationship of the classes Armophorea and Litostomatea within the SAL (Spirotrichea + Armophorea + Litostomatea) supercluster in that the partners unite ventral-to-dorsal and the main body axes are antiparallel. On the other hand, the last common ancestor of the spirotricheans very likely had a ventral-to-ventral and homopolar conjugation mode with the main body axes oriented in parallel.

Morphology and systematics of two freshwater Frontonia species (Ciliophora, Peniculida) from northeastern China, with comparisons among the freshwater Frontonia spp.

The morphology and infraciliature of two Frontonia species, F. shii spec. nov. and F. paramagna Chen et al., 2014, isolated from a freshwater pond in northeastern China, were investigated using living observation and silver staining methods Frontonia shii spec. nov. is recognized by the combination of the following characters: freshwater Frontonia, size in vivo about 220–350 × 130–250 μm, elliptical in outline; 128–142 somatic kineties; three or four vestibular kineties, six or seven postoral kineties; peniculi 1–3 each with four kineties; single contractile vacuole with about 10 collecting canals. The improved diagnosis for F. paramagna is based on the current and previous reports. Comparisons among freshwater Frontonia are also provided. The small subunit ribosomal rRNA gene (SSU rDNA) sequences of the two species are characterized and phylogenetic analyses based on these sequences show that both species fall into the core clade of the genus Frontonia, and this genus is not monophyletic.

Morphological descriptions of five scuticociliates including one new species of Falcicyclidium

Five scuticociliates, collected from China, were morphologically studied using standard methods One represents a new member of the genus Falcicyclidium, F. citriforme nov. spec., which can be recognised mainly by a combination of the following characters: usually two macronuclear nodules, buccal field about half of body length, ten somatic kineties, about 22 kinetal units in somatic kinety 1 and n, and excretory pore near posterior end of somatic kinety n. A redescription for Biggaria bermudensis was provided to include the feature of scutica and argyrome based on new isolate, and variations between different isolates were also discussed. The new population of Sathrophilus holtae differs from the type population by two postoral kineties and fewer kinetal units in the scutica. Its stomatogenesis belongs to the scuticobuccokinetal type, which shows similarities with Dexiotricha among loxocephalids. Morphometric data and brief descriptions were supplied for another two species, i.e., Protocyclidium citrullus and Cyclidium varibonneti.

Molecular Phylogeny and Taxonomy of a New Freshwater Hymenostomatid from Northeastern China, with the Establishment of a New Genus Anteglaucoma gen. n. (Protista, Ciliophora, Oligohymenophorea).

The morphology, infraciliature and SSU rDNA sequence of a new freshwater hymenostomatid ciliate, Anteglaucoma harbinensis gen. nov., spec. nov., collected from a farmland pond in Harbin, China, were investigated. The new genus Anteglaucoma is characterized as follows: small to medium-sized Glaucomidae with oral apparatus in anterior one-third of cell; paroral membrane composed of almost longitudinally arranged dikinetids; three adoral membranelles nearly equal in length and arranged almost longitudinally in parallel; silverline pattern tetrahymenid. The improved diagnosis of family Glaucomidae Corliss 1971 is provided based on the previous and present work. The type species Anteglaucoma harbinensis spec. nov. is defined by having 32-35 somatic kineties; four or five postoral kineties; membranelle 1 and membranelle 2 having five or six kinetosomal rows, membranelle 3 having three kinetosomal rows; single macronuclear nodule; contractile vacuole on average 15% from posterior body end; locomotion characterized by crawling with a rather hectic jerking motion; freshwater habitat. Phylogenetic analyses show that Anteglaucoma clusters in the family Glaucomidae and groups with the genera Glaucoma. The molecular and morphological data indicate that Glaucomidae is related to the family Bromeliophryidae in the phylogenetic trees.

Morphology and molecular phylogeny of Aegyria foissneri sp. n. and Lynchella minuta sp. n. (Ciliophora, Cyrtophoria) from brackish waters of southern China

The morphology, ciliary pattern and small subunit rDNA (SSU rDNA) sequences of two new cyrtophorian ciliates, Aegyria foissneri sp. n. and Lynchella minuta sp. n., isolated from brackish waters in southern China, were investigated. Aegyria foissneri sp. n. is characterized as follows: cell size 85–170×45–80μm in vivo; body inverted oval with a protrusion and a dark pigment spot on anterior left part; 42–77 somatic kineties; one preoral and three to six circumoral kineties; five to eight transpodial segments; 31–44 nematodesmal rods; 12–16 contractile vacuoles; and single oval macronucleus. Lynchella minuta sp. n. is distinguished from its congeners by having a cell size of 20–30×15–20μm in vivo, oval body outline; four preoral and 14 or 15 postoral kineties, three circumoral kineties; ca. 11 nematodesmal rods; one finger-like tentacle on the ventral side; and two diagonally located contractile vacuoles. Molecular phylogenetic analyses support the genus assignment of Aegyria foissneri sp. n. and indicate the monophyly of the genus. While Lynchella minuta sp. n. clusters with Coeloperix species, which indicates that Lynchella is non-monophyletic.

Morphology and Molecular Phylogeny of Two Poorly Known Species of Protocruzia (Ciliophora: Protocruziida).

The ciliate genus Protocruzia is a highly confused group, which was formerly placed in the class Heterotrichea or Karyorelictea, and is according to the most recent system tentatively assigned to the class Spirotrichea. In the present study, the morphology, ciliary pattern, and molecular phylogeny of two poorly known species, Protocruzia tuzeti Villeneuve-Brachon, 1940, and Protocruzia granulosa Kahl, 1933, isolated from coastal waters of China, were investigated. Protocruzia tuzeti differs from its congeners mainly in possessing 6 adoral membranelles, 8-11 somatic kineties, and postoral dikinetids. Protocruzia granulosa is characterized by its extremely slender body, three postoral kineties, and 13 or 14 somatic kineties. The morphogenesis of P.granulosa is similar to that of P.tuzeti, especially in the parakinetal mode of stomatogenesis and the reorganization of the parental paroral membrane; however, more than one somatic kinety joins in the formation of the oral primordium in P.granulosa. Phylogenetic analyses based on small subunit ribosomal RNA gene revealed that six Protocruzia species form a fully supported clade that does not belong to any ciliate class; therefore, our data support the establishment of the class Protocruziea Gao etal. (Sci. Rep., 6, 2016, 24874).

New contributions to the biodiversity of ciliates (Protozoa, Ciliophora) from Antarctica, including a description of Gastronauta multistriata nov. spec.

Antarctica is a remote and isolated biotope which makes it an ideal location for studying new and endemic species. Since there is little literature available on the diversity of ciliates in this area, a taxonomic survey of ciliates from melt-water of Collins glacier, King George Island, was carried out from January to March 2006. As a result, the morphology and infraciliature of five ciliates, including one new species, are described using live observations and silver staining: Gastronauta multistriata nov. spec., Neokeronopsis asiatica Foissner et al., 2010, Paraholosticha muscicola Kahl, 1932, Oxytricha sp., and Cyclidium glaucoma Muller, 1786. Gastronauta multistriata nov. spec. is distinguished from its congeners by the following combination of characters: cell size in vivo on average 80 × 40 μm; 5–9 kineties in left ciliary field; 18–23 kineties in right ciliary field, including 10–12 postoral kineties; 7–10 preoral kineties; dorsal brush along anterior dorsal margin, consisting of 5–8 groups of basal bodies. The only minor differences between the current population of N. asiatica and a previously described Antarctic population are the numbers of caudal cirri (6–10 vs. 8–15) and dorsal kineties (11–13 vs. 12–18). Paraholosticha sterkii is synonymised with P. muscicola. The Antarctic population of C. glaucoma corresponds well with a former population from China, the only difference being the number of kinetids in SK n (11–17 vs. 9–11). This work will contribute to the understanding of ciliate diversity in this little studied area.

Mutational robustness of morphological traits in the ciliate Tetrahymena thermophila.

Ciliate nuclear architecture, in particular the sequestration of a transcriptionally silent germline genome, allows for the accumulation of mutations that are "hidden" from selection during many rounds of asexual reproduction. After sexual conjugation, these mutations are expressed, potentially resulting in highly variable phenotypes. Morphological traits are widely used in ciliate taxonomy, however, the extent to which the values of these traits are robust to change in the face of mutation remains largely unknown. In this study, we examine the effects of mutations accumulated in the germline genome to test the mutational robustness of four traits commonly used in ciliate morphological taxonomy (number of somatic kineties, number of postoral kineties, macronuclear size, and cell size). We found that the number of postoral kineties is robust to mutation, confirming that it should be preferentially used in taxonomy. By contrast, we found that, as in other unicellular and multicellular species, cell and macronucleus sizes change in response to mutation. Thus, we argue that cell and macronucleus sizes, which are widely used in taxonomy, should be treated cautiously for species identification. Finally, we found evidence of correlations between cell and macronucleus sizes and fitness, suggesting possible mutational pleiotropy. This study demonstrates the importance of, and methods for, determining mutational robustness to guide morphological taxonomy in ciliates.

Morphology and Phylogeny of a New Frontonia Ciliate, F. paramagna spec. nov. (Ciliophora, Peniculida) from Harbin, Northeast China.

This paper describes a new Frontonia ciliate, F. paramagna spec. nov., sampled from freshwater in Harbin, northeast China, based on its morphology, infraciliature, ultrastructure and small subunit ribosomal RNA gene information. The new species is defined by the following features: large sized freshwater form, 400-610 × 110-160 μm in vivo, about 179-201 somatic kineties, three peniculi, each with four kineties, three vestibular and six or seven postoral kineties, one elongated-elliptical macronucleus, centrally-located, a single contractile vacuole, without canals, located right-dorsally in the posterior half of the body. Sequence alignment and phylogenetic analyses based on the small subunit ribosomal RNA (SSU rRNA) gene indicated that the new species has characters distinct from its known congeners. The ultrastructure of the trichocyst and other extrusomes, and the subpellicular fibre system, were observed by both scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Much of the ultrastructure is here given for the first time by SEM, and these features provide complementary data for taxonomic purposes.

Morphological reports on two species of Dexiotricha (Ciliophora, Scuticociliatia), with a note on the phylogenetic position of the genus

Two Dexiotricha species (Dexiotricha elliptica nov. comb. and Dexiotricha cf. granulosa), respectively isolated from soil north-west of Riyadh, Saudi Arabia, and freshwater in Shanghai, eastern China, were investigated using standard methods. The species Loxocephalus ellipticus Kahl, 1931 is reclassified here in the genus Dexiotricha and was characterized mainly by constantly showing 16 somatic kineties, three post-oral kineties with the middle one shortened, a contractile vacuole located subcaudally with an excretory pore near the posterior end of somatic kinety 2 and single caudal cilia. A Dexiotricha granulosa-like organism having a subcaudally located contractile vacuole and fewer somatic kineties was designated D. cf. granulosa. The small-subunit rRNA gene (SSU rDNA) sequences of these two species were characterized and their phylogenetic positions based on SSU rDNA sequences were revealed by means of Bayesian inference and maximum-likelihood analysis. Phylogenetic analyses confirmed Dexiotricha as a monophyletic genus and supported its assignment to the order Loxocephalida. However, its family assignment remains unsupported.

Taxonomic studies on three marine ciliates from China, including a new species (Ciliophora, Cyrtophorida)

The present work investigates the living morphology and infraciliature of three marine cyrtophorid ciliates, which were isolated from Qingdao, China. Compared with its congeners, Orthotrochilia sinica spec. nov. can be distinguished by a combination of features: body slender and elliptical in outline, size about 50–60 × 20–25 μm in vivo, 18–21 somatic kineties, the length of the left perioral kinety treble the length of the right one, two ventrally located contractile vacuoles on the right side, and 25–32 nematodesmal rods. Based on current observations and the previous description, the diagnosis of Trochilioides tenuis (Deroux, 1976) Chen et al. 2011 is improved: cell size 30–40 × 20–35 μm in vivo, oval shaped in outline; consistently three right kineties, four left kineties and seven postoral kineties; a single contractile vacuole; marine habitat. A second species of Trochilioides, T. recta (Kahl, 1923) Chen et al. 2011 is re-described based on a Chinese population. Furthermore, a key to the identification of species of the genus Trochilioides whose infraciliature data are available is supplied, and Chlamydonyx trivialis (Fenchel, 1965) comb. nov. [basionym: Trochilioides trivialis Fenchel, 1965] is suggested.

Studies on three diverse Frontonia species (Ciliophora, Peniculida), with brief notes on 14 marine or brackish congeners

Living observation and silver impregnation methods were used to investigate the morphology and infraciliature of three Fronto- nia ciliates (F. guangdongensis spec. nov., F. ocularis Bullington, 1939 and F. schaefferi Bullington, 1939) that were isolated from coastal waters of the South China Sea. Frontonia guangdongensis spec. nov. may be recognized by the combination of the following characteristics: cells about 160 × 35 μm in vivo; elongated body with right margin depressed in anterior third; length to width ratio 4:1 to 5:1; three or four vestibular and four or fi ve postoral kineties; peniculi 1 and 2 each with four rows of kineties, peniculus 3 with two rows; one contractile vacuole in mid-body region right of cell median; brackish water habitat. A key based on morphological data for fourteen marine or brack- ish water Frontonia species found in China is also provided. In addition, the small subunit (SSU) rDNA gene was sequenced for F. ocularis Bullington, 1939. Our phylogenetic analyses support the contention that the genus Frontonia is not monophyletic.

Frontonia anatolica n. sp., a new peniculid ciliate (Protista, Ciliophora) from Lake Van, Turkey

The morphology, ciliature, and silverline system of a new ciliate, Frontonia anatolica n. sp., isolated from the bottom sediment of the eastern shore of Lake Van, a large alkaline lake in Eastern Anatolia Turkey, were investigated using live and silver impregnation methods. Frontonia anatolica n. sp. is characterised by an elliptical body shape; by an in-vivo body size of 101-134 x 47-67 \mum; by dorsoventral flattening of about 2:3 to 1:2; by 2 contractile vacuoles located in the anterior and posterior body parts, each with 6-7 collecting canals and 1 excretory pore; by about 93 somatic kineties; by 3 vestibular and 3-5 postoral kineties; and by peniculi 1 and 2 each having 4 ciliary rows, and peniculus 3 having 2 ciliary rows.

The effects of thyroid hormones on uroflowmetry parameters in asymptomatic women

The morphology, ciliature, and silverline system of a new ciliate, Frontonia anatolica n. sp., isolated from the bottom sediment of the eastern shore of Lake Van, a large alkaline lake in Eastern Anatolia Turkey, were investigated using live and silver impregnation methods. Frontonia anatolica n. sp. is characterised by an elliptical body shape; by an in-vivo body size of 101-134 x 47-67 mm; by dorsoventral flattening of about 2:3 to 1:2; by 2 contractile vacuoles located in the anterior and posterior body parts, each with 6-7 collecting canals and 1 excretory pore; by about 93 somatic kineties; by 3 vestibular and 3-5 postoral kineties; and by peniculi 1 and 2 each having 4 ciliary rows, and peniculus 3 having 2 ciliary rows.

Morphology and SSU rRNA gene sequences of three Frontonia species, including a description of F. subtropica spec. nov. (Ciliophora, Peniculida)

The morphology and infraciliature of three Frontonia species, F. subtropica spec. nov., F. canadensis Roque and Puytorac, 1972, and F. magna Fan et al., 2011, isolated from coastal waters in southern China sea, were investigated using living observation and silver impregnation methods. Frontonia subtropica spec. nov. is recognized by the combination of the following characters: body elliptical in outline with right margin depressed in anterior third, about 180–230μm×60–80μm in vivo; 104–114 somatic kineties; peniculi 1–3 each with four kineties; five vestibular and five postoral kineties; one centrally located elongate-elliptical macronucleus; single contractile vacuole located left-dorsally in posterior third of body. We also provide improved diagnoses for F. canadensis and F. magna based on current and previous reports. The small subunit (SSU) rRNA gene was sequenced for all three species. Comparisons with sequences of morphologically similar congeners clearly support the validity each species.