Left Marginal Cirri Research Articles

Redescription and phylogenetic position of the terrestrial ciliates Gastrostylides dorsicirratus and Heterourosomoida lanceolata (Hypotricha, Dorsomarginalia)

The morphology and infraciliature of two soil hypotrichous ciliates, Heterourosomoida lanceolata (Shibuya, 1930) Singh and Kamra, 2015 and Gastrostylides dorsicirratus (Foissner, 1982) Foissner, 2016, were investigated using live observation and protargol staining. The Chinese population of H. lanceolata differs slightly from other populations in the body size in vivo, the relative length of the adoral zone, the number of right and left marginal cirri, the total number of dorsal bristles, and the number of micronuclei. The Chinese population of G. dorsicirratus corresponds well with Austrian and Indian populations. We also document the morphogenetic processes during binary fission of G. dorsicirratus, including the formation of the frontoventral-transverse cirral anlagen in a primary pattern. In addition, phylogenetic analyses based on SSU rDNA sequence data reveal that the two populations of G. dorsicirratus for which data are available cluster together with full support and form a clade with Heterourosomoida sinica and two populations of H. lanceolata.

A barotolerant ciliate isolated from the abyssal deep sea of the North Atlantic: Euplotes dominicanus sp. n. (Ciliophora, Euplotia)

A new Euplotes species, isolated from abyssal depths (>4000 m) of the North Atlantic Ocean, was described based on morphology, ciliary pattern and molecular data. Euplotes dominicanus sp. n. is characterized by a small body size (29–40 × 17–27 μm in vivo), 18–22 adoral membranelles, 10 frontoventral, five transverse and two left marginal cirri and one caudal cirrus, five or six dorsolateral kineties with 7–9 dikinetids in mid-dorsolateral kinety (DK3), and dorsal silverline system of the double-eurystomus type. Phylogenetic analyses inferred from 18S rRNA sequences show that Euplotes dominicanus sp. n. is most closely related to E. curdsi, with a sequence similarity of 97.6 %. Euplotes dominicanus sp. n. was able to survive hydrostatic pressures up to 500 bar indicating its barotolerance. Metabarcoding data demonstrate the presence of E. dominicanus sp. n. in sediments of several deep-sea basins.

Morphology and phylogeny of four marine or brackish water spirotrich ciliates (Protozoa, Ciliophora) from China, with descriptions of two new species

In this study, we investigated the morphology and molecular phylogeny of four marine or brackish spirotrichean ciliates found in China, namely: Caryotricha sinica sp. nov., Prodiscocephalus orientalis sp. nov., P. cf. borrori, and Certesia quadrinucleata. Caryotricha sinica is characterized by its small size, seven cirral rows extending posteriorly to about 65% of the cell length, and four transverse cirri. Prodiscocephalus orientalis differs from its congeners mainly by the number of cirri in the “head” region and on the ventral side. The SSU rDNA sequence of P. cf. borrori differs from that of other population of P. borrori by ca. 40 bp. Consequently, the nominal species P. borrori is considered to be a species-complex. New data are provided for Certesia quadrinucleata. The Chinese population of C. quadrinucleata, for example, has fewer left marginal cirri than the other populations for which such data are available. Phylogenetic analyses based on SSU rDNA sequence data show that the genus Caryotricha is monophyletic. All typical “discocephalids” with a discoid “head” form a strongly supported clade that is sister to the unstable uronychiids + pseudoamphisiellids clade within the Euplotia. The genus Certesia forms a sister group to the Euplotes clade, also within the Euplotia assemblage.

Taxonomic description of a new marine ciliate, Euplotes qingdaoensis n. sp. (Ciliophora: Euplotida)

The characteristics and infraciliature of a new euplotid ciliate, Euplotes qingdaoensis n. sp., discovered from the coastal waters of Jiaozhou Bay, northern China, were studied using live observation and silver impregnation. The new marine species is characterized by a slightly flattened body (90–110 μm×70–80 μm, in vivo), an adoral zone of 26–29 membranelles, 10 strong frontoventral and five transverse cirri, two caudal cirri, a single left marginal cirrus, seven dorsal kineties, a middle kinety with about 15 pairs of basal bodies, a silverline system of the double-eurystomus type, and a C-shaped macronucleus.

Taxonomic Descriptions of Two Marine Ciliates, Euplotes dammamensis n. sp. and Euplotes balteatus (Dujardin, 1841) Kahl, 1932 (Ciliophora, Spirotrichea, Euplotida), Collected from the Arabian Gulf, Saudi Arabia

The morphology, morphogenesis and infraciliature of two marine euplotid ciliates, Euplotes dammamensis n. sp. and Euplotes balteatus (Dujardin, 1841) Kahl, 1932, isolated from a sandy beach of the Arabian Gulf, Saudi Arabia, were investigated using observa- tions in vivo and protargol-impregnation methods. Euplotes dammamensis n. sp. is characterized by a combination of features including its huge body size (100-170 × 80-120 μm), 10 conspicuous dorsal ridges, 10 normal-sized frontoventral and two marginal cirri, and 11 dorsal kineties. Euplotes balteatus is mainly characterized by 10 frontoventral, two caudal, and two left marginal cirri, 7-10 dorsal kineties and 5-7 prominent dorsal ridges as well as double-eurystomus silverline system. The small subunit rRNA (SSU-rRNA) gene sequences were determined for both species and phylogenetic analyses based on these data indicated that E. dammamensis is most closely related to E. parabalteatus Jiang et al., 2010, and E. balteatus clusters with E. plicatum Valbonesi et al., 1997, E. orientalis Jiang et al., 2010, and E. bisulcatus Kahl, 1932.

Morphology and SSU rRNA gene‐based phylogeny of two Diophrys‐like ciliates from northern china, with notes on morphogenesis of Pseudodiophrys nigricans (Protozoa, Ciliophora)

Two free-living marine euplotid ciliates, Pseudodiophrys nigricans and Diophrys japonica, collected from the coastal waters off Qingdao, northern China, were investigated using live observations and protargol impregnation methods. The cortical development of P. nigricans was observed during binary division. Although its general pattern of morphogenesis is similar to that of other Diophrys-like species, three unusual features are noteworthy: 1) the frontoventral transverse cirral anlagen develop in the secondary mode, similar to that of Euplotes; 2) the undulating membrane anlage migrates far from the cytostome and does not split into two membranes; and 3) the parental adoral zone of membranelles remains nearly intact throughout the entire morphogenetic process. Diophrys japonica is redescribed based on a Chinese population and can be recognized by having one left marginal cirrus, densely arranged cortical granules, and a fragment kinety with three dikinetids. Phylogenetic analyses based on the small subunit rRNA (SSU rRNA) gene sequence data indicate that D. japonica is placed within the Diophrys clade and is most closely related to the well-known D. apoligothrix.

Morphological, Ultrastructural, and Molecular Characterization of Euplotidium rosati n. sp. (Ciliophora, Euplotida) from Guam

We combined morphological (i.e. live, stained, scanning, and transmission electron microscopy) with morphometric and molecular analysis to describe a ciliate species collected from shallow reefs in Guam, grown, and maintained in our laboratory. The species was recognized as a member of Euplotidium, and compared with established species of the genus: Euplotidium itoi Ito 1958; Euplotidium psammophilus (Vacelet 1961) Borror 1972; Euplotidium arenarium Magagnini and Nobili 1964; Euplotidium helgae Hartwig 1980; Euplotidium prosaltans Tuffrau 1985, and Euplotidium smalli Lei, Choi and Xu, 2002. To obtain more elements to compare the species, new morphometric data and additional SSU rRNA gene sequences of E. itoi and of E. arenarium are reported. On the basis of this comparison, we established the new species Euplotidium rosati that has a cirral pattern composed of 12 frontoventral and six transverse cirri, and lacks the left marginal cirrus. Euplotidium rosati harbors on its dorsal surface epixenosomes, the peculiar extrusive symbionts described in other Euplotidium species. The whole body of our observations together with the analysis of the data available in the literature leads us to propose a redefinition of the genus. The results may also be useful to clarify the tangled relationship between Euplotidium and Gastrocirrhus.

Morphogenesis and morphology of Certesia quadrinucleata (Protozoa: Ciliophora) from Japan

The morphogenesis and morphology of the marine benthic ciliate Certesia quadrinucleata collected from seawater in Nagasaki Mie Port, Japan, were investigated using microscopic observation of live and protargol-stained specimens. In terms of its morphology, the current isolate possesses diagnostic features of the genus and the species: a row of left marginal cirri, a prominent paroral membrane, 11 frontoventral cirri scattered in frontoventral area, five highly developed transverse cirri, four macronuclear nodules, five dorsal kineties and a caudally located contractile vacuole. Its morphogenesis belongs to the ‘Certesia’ subtype, and main events can be summarized as follow: (1) the oral primordium in the opisthe develops de novo in a subcortical pouch; (2) the old paroral membrane is completely replaced by the new one in the proter, but the parental adoral zone of membranelles is wholly inherited; (3) five streaks of cirral anlagen are formed in a primary mode for the proter and the opisthe, which gives rise to cirri in the pattern of 3:3:3:3:3 from left to right; (4) the leftmost frontoventral cirrus develops de novo on the cell surface in both dividers, and has no connection with the undulating membrane anlage; and (5) the anlagen for marginal cirri and dorsal kineties occur intrakinetally. Current observations confirm the separation of Certesiidae from other euplotids at the familial level.

Morphological redescriptions of three Cyrtohymena ciliates (Ciliophora: Sporadotrichida: Oxytrichidae) new to Korea

Three ciliate species of genus Cyrtohymena, C. australis Foissner, 1995, C. citrina (Berger & Foissner, 1987) and C. muscorum (Kahl, 1932) new to Korea, were collected from semi-terrestrial habitats. The description was based on the observation of live and silver stained specimens. Diagnostic characteristics of these species are as follows. C. autralis: size about in live specimens. Cortical granules yellowish. 18-31 right and 31-40 left marginal cirri in number. Dorsal kineties eight rows. C. citrina: size about in live specimens. Cortical granules yellowish. 26-32 right and 23-27 left marginal cirri in number. Dorsal kineties five to six rows. C. muscorum: size about in live specimens. Cortical granules reddish. 31-34 right and 33-36 left marginal cirri in number. Dorsal kineties six rows. Three species of Cyrtohymena have been added to Korean ciliate fauna from this study. Including previous one species of C. quadrinucleata, four species of this genus in total have been recorded so far in this country.

Morphological Redescription and Morphogenesis of Urosoma macrostyla (Wrześniowski, 1866) Berger, 1999 (Ciliophora, Hypotrichida)

The morphology and morphogenesis of the hypotrich ciliate Urosoma macrostyla (Wrześniowski, 1866) Berger, 1999, collected from a puddle in Harbin, China, were investigated using live observation and protargol impregnation. Based on previous and present studies, an improved diagnosis of U. macrostyla is supplied. It differs from its congeners mainly by the body shape, no cortical granules and number of macronuclear nodules. The ontogenesis of U. macrostyla is typical for species with such a somatic ciliary pattern: the oral primordium develops hypoapokinetally and FVT-anlagen develop in 5-streaks and primary mode. However, a unique characteristic in morphogenetic process is reported: anlagen for both the left and right marginal cirri occur de novo to the right of the parental structure which has never been seen in other oxytrichids. This characteristic was considered an apomorphy (Berger 1999). This indicates that U. macrostyla possibly has a high phylogenetic position within the genus Urosoma , or perhaps it represents a distinct subgenus.

First Record of Three Uronychia Species (Ciliophora: Spirotrichea: Euplotida) from Korea

Three morphospecies of the genus Uronychia, i.e. U. setigera Calkins, 1902, U. binucleata Young, 1922, and U. multicirrus Song, 1997, were collected from the coastal waters of Gumjin-ri on the East Sea and the public waterfront of Incheon on the Yellow Sea in Korea, respectively. These species are described based on live observation, protargol impregnation, silver nitrate impregnation, and their morphometrics. Diagnostic keys for these species are also provided. In addition, their small subunit ribosomal DNA sequences were compared with previously known sequences of Uronychia species. Diagnostics of three Uronychia species are as follows: U. setigera: 50-80 μm long in vivo, oval-shaped, 2 macronuclear nodules (Ma), 1 spur on the left margin, 11 adoral membranelles (AM) 1, 4 AM2 , 1 buccal cirrus (BC), 4 frontal cirri (FC), 3 left marginal cirri (LMC), 2 ventral cirri (VC), 5 transverse cirri (TC), 3 caudal cirri (CC), 6 dorsal kineties (DK), and approximately 23 cilia in the leftmost kinety. U. binucleata: 70-110 μm long in vivo, oval to slightly rectangular shaped, 2 Ma, 1 micronucleus (Mi), 2 spurs on the posterior region, 11 AM1, 4 AM2, 1 BC, 4 FC, 3 LMC, 2 VC, 5 TC, 3 CC, 6 DK, and approximately 37 cilia in the leftmost kinety. U. multicirrus: 140-200 μm long in vivo, oval to slightly rectangular shaped, ca. 7 Ma, 1 Mi, 11 AM1, 4 AM2, 1 BC, 4 FC, 3 LMC, approximately 8 VC, 5 TC, 3 CC, and 6 DK. This study presents the first record of this genus in Korea.

Morphological and molecular characterization of Euplotes encysticus (Protozoa: Ciliophora: Euplotida)

The ciliate Euplotes encysticus Yonezawa, 1985 was insufficiently described so far regarding its living morphology, infraciliature and silverline system. Recently, a China population was isolated from brackish water (salinity 6‰) near a coastal sandy beach (114°32′E 22°43′N) of the Daya Bay, South China Sea and subsequent investigations were performed on it in detail. Based on data available, the morphology of this species was summarized and a new diagnosis is given which is characterized by: medium-sized body with consistently 9 frontoventral, 2 caudal and 2 left marginal cirri; 30–40 adoral membranelles; 7 dorsal kineties; dorsal silverline system consisting of complex type with irregular network; capable of encystment. Both the morphology and SSr RNA gene sequence show, with high support, a close relationship of E. encysticus and Euplotes muscorum.

Comparison of ciliature microtubule organelles in three hypotrichous ciliate species

We examined the structure and spatial organization of ciliature base-associated microtubules (BAM) in three hypotrichous ciliates (Stylonychia mytilus, Pseudourostyla cristata, Euplotes woodruffi) in fluorescence microscopy. The results revealed that BAM, including the anterior (ALM), posterior longitudinal microtubule (PLM) and the transverse microtubule (TM) bands, are composed of tubulin. The respective microtubular bands have cytoplasmic polarization patterns that are significantly asymmetric. The BAM of the midventral files in P. cristata appear cord-shaped compared with the ALM bands of transverse cirri in both S. mytilus and E. woodruffi, which extend to the left anterior side of the cell before converging. The TM bands of the left marginal cirri (MC) in S. mytilus extend to the right side of the cell, while those of the right MC bands extend to the left. Our observations suggest that BAM traits are common in hypotrichous ciliates even though different species possess different microtubule arrangements related to the conserved cirral morphogenetic patterns in the respective species. The differing development of BAM in the three ciliate suggests that the microtubules may be conserved in different hypotrichs. We have also demonstrated that the BAM, which appear polar and asymmetric, are localized in specific cytoskeletal positions and extend in different orientations within the cortex to connect with other ciliature-associated structures and, thus, strengthen the cortex. These BAM features indicate that they are directly associated with cell motion.

Morphological studies and molecular data on a new marine ciliate, Apokeronopsis sinica n. sp. (Ciliophora: Urostylida), from the South China Sea

The morphology of a new marine urostylid ciliate, Apokeronopsis sinica n. sp., collected from the Clear Water Bay, Hong Kong, was investigated. Additionally, the SSrRNA gene was sequenced in order to make a comparison at molecular level. Based on both morphological and molecular data, descriptions and comparisons with its congeners are provided. Apokeronopsis sinica is characterized by: body size about 150–200 × 50–65 µm in vivo; two kinds of cortical granules; about 20 cirri in frontal area which form the non-typical bicorona; 2 frontoterminal, ca. 4 buccal and 10 transverse cirri; midventral complex consists of 21–32 pairs of cirri; on average 35 right and 30 left marginal cirri; about 50 membranelles; invariably 3 dorsal kineties. A key to the identification of the known Apokeronopsis species was suggested. The small subunit rRNA gene sequence differences between Apokeronopsis sinica and its congeners range from 1.64% to 3.72%.

Morphology, Ultrastructure, Molecular Phylogeny, and Autecology of Euplotes elegans Kahl, 1932 (Hypotrichida; Euplotidae) Isolated from the Anoxic Mariager Fjord, Denmark

The morphology, autecology, and molecular phylogeny of an euryhaline Euplotes isolate collected from the anoxic water column of the Mariager Fjord in Denmark were investigated. The isolate matches the original description of Euplotes elegans Kahl, 1932 very well. However, its dorsal silverline system is clearly distinct from the redescription of this species by Tuffrau. Thus, a neotypification is proposed for E. elegans Kahl, 1932. The oval-shaped cell has a mean size of 107 x 51 microm and is characterized by 9.4 dorsolateral kineties, seven prominent dorsal ridges, large elongated ampullae, which encircle the dorsal kinetids, 18 kinetids in the middorsal row, nine frontoventral cirri, five transversal cirri, and three caudal cirri (two right caudal cirri and one left marginal cirrus). The dorsal silverline system is of the double type with the narrow polygons located on the right side of the dorsal kinetids. The ecological tolerances of this species to pH, salinity, temperature, and oxygen match the ambient environmental conditions of the sampling site. Molecular phylogeny was studied using small subunit rRNA (SSU rRNA) gene sequences. The molecular data cluster E. elegans with Euplotes raikovi, a member of the Euplotopsis group. The data suggest that the E. elegans-E. raikovi clade represents an isolated and deep branch at the base of the Euplotes tree.

Benthic ciliates from Sepetiba Bay (Rio de Janeiro, Brazil) with description of Pseudokeronopsis sepetibensis n. sp. (Spirotrichea: Urostylida)

During the period from 2001 to 2002, we examined samples of water and sediment from five stations in Sepetiba Bay, located in the south region of Rio de Janeiro state, Brazil. We identified 32 species of ciliate protists representing seven classes: Karyorelictea, Heterotrichea, Spirotrichea, Litostomatea, Phyllopharyngea, Protostomatea and Oligohymenophorea. Among the Spirotrichea, we discovered Pseudokeronopsis sepetibensis n. sp., characterized by a unique combination of three features: 3 contractile vacuoles, an inconspicuous mid-ventral row, and 4 5 frontoterminal cirri. It showed yellow-greenish coloration and elongated body outline (100 140 m x 20 26 m). On average, there were 44 adoral membranelles, 50 left marginal cirri, 48 right marginal cirri and 41 mid-ventral cirri disposed in a straight row past the level of the oral region. Other features include 4 frontoterminal cirri and a constant number of 3 transverse cirri; 8 frontal cirri (4 anterior and 4 posterior arranged as an atypical bicorone).

Pleurotricha curdsi (Shi, Warren and Song 2002) nov. comb. (Ciliophora: Hypotrichida): morphology and ontogenesis of an Indian population; redefinition of the genus

The oxytrichid ciliate Pleurotricha curdsi (140 × 64 μm) is widely distributed in the tributaries of the river Yamuna in Delhi. The vegetative ciliature consists of 20 frontal-ventral-transverse (FVT) cirri (9 frontal, 6 ventral and 5 transverse), two rows of right marginal cirri (RMC) and one row of left marginal cirri, four dorsal kineties, two dorsomarginal rows and three caudal cirri (CC), as well as the usual adoral zone of membranelles and two undulating membranes. A morphometric comparison between the Indian and Chinese populations of P. curdsi shows significant strain differences. On the basis of its morphological and morphogenetic features P. curdsi qualifies to be an oxytrichid sensu stricto. However, the presence of 20 FVT cirri in this species is a non-conforming feature as all other members of this group have been reported to possess 18 or

Influence of cadmium on development of surface ciliary structures in the ciliate Stylonychia mytilus (Ciliophora, Oxytrichidae)

Summary The effect of cadmium on the morphogenesis and patterning of surface ciliary structures has been analyzed in the ciliate protozoan Stylonychia mytilus. During division and cortical reorganization, Stylonychia cells exhibit development of ciliary structures, consisting of an adorai zone of membranelies (AZM), two undulating membranes, frontoventral-transverse (FVT) cirri, a row each of right and left marginal cirri, dorsal kineties and caudal cirri which differentiate from their respective ciliary primordia. Subsequent patterning results in a species specific spatial arrangement of ciliary structures. The presence of cadmium in the culture medium disturbs the development process in that the cells develop supernumerary ciliary primordia which differentiate to form 3–7 extra FVT cirri, one or more additional dorsal kineties, and caudal cirri. The additional cirri exhibit quantitative features which are characteristic of their spatial position on the cell surface. The anomalous ciliary patterns are transitory and are reversed when cells divide or reorganize in the cadmium free medium. In the presence of cadmium, configuration of the new AZM becomes distorted as the newly differentiated membranelies near the cytostome fail to align correctly due to their torsional displacement. Development of additional ciliary structures is not accompanied by significant morphometric changes in the cells.

Description of a new freshwater ciliate, Euplotes shanghaiensis nov. spec. from China (Ciliophora, Euplotidae)

Summary A new freshwater ciliate, Euplotes shanghaiensis nov. spec. isolated from a pond in Shanghai, China is described. Its morphology, infraciliature and silverline system were studied by light microscopy in vivo and following nigrosin staining, protargol and dry silver nitrate impregnation. E. shanghaiensis is a medium-sized species, body in vivo about 80–120×50–80 μm with 10 frontoventral, 5 transversal, 2 caudal and 2 left marginal cirri; ca. 54–58 membranelles in the adoral zone; 12–13 dorsal kineties, of which the middle one contains about 21–26 pairs of basal bodies. The new species differs from the other “double- eurystomus type dorsal argyrome” and “10-frontoventral-cirri” congeners with respect to the particular D-formed body shape, evenly curved adoral zone of membranelles, conspicuously large buccal field which is up to 4/5 of the both length and higher number of dorsal ciliary rows with densely packed kinetosomes.

Observations on the Morphology and Taxonomy of a Marine Ciliate Species of the Genus Diophrys (Ciliophora: Euplotida)

Observations on the Morphology and Taxonomy of a Marine Ciliate Species of the Genus Diophrys (Ciliophora: Euplotida)