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The formation of resting cysts commonly found in unicellular eukaryotes is a complex and highly regulated survival strategy against environmental stress that involves drastic physiological and biochemical changes. Although most studies have focused on the morphology and structure of cysts, little is known about the molecular mechanisms that control this process. Recent studies indicate that DNA N 6-adenine methylation (6mA) could be dynamically changing in response to external stimuli; however, its potential role in the regulation of cyst formation remains unknown. We used the ciliate Pseudocohnilembus persalinus, which can be easily induced to form cysts to investigate the dynamic pattern of 6mA in trophonts and cysts. Single-molecule real-time (SMRT) sequencing reveals high levels of 6mA in trophonts that decrease in cysts, along with a conversion of symmetric 6mA to asymmetric 6mA. Further analysis shows that 6mA, a mark of active transcription, is involved in altering the expression of encystment-related genes through changes in 6mA levels and 6mA symmetric-to-asymmetric conversion. Most importantly, we show that reducing 6mA levels by knocking down the DNA 6mA methyltransferase PpAMT1 accelerates cyst formation. Taken together, we characterize the genome-wide 6mA landscape in P. persalinus and provide insights into the role of 6mA in gene regulation under environmental stress in eukaryotes. We propose that 6mA acts as a mark of active transcription to regulate the encystment process along with symmetric-to-asymmetric conversion, providing important information for understanding the molecular response to environmental cues from the perspective of 6mA modification.
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Metilación de ADN , Eucariontes , Eucariontes/genética , ADN/química , Regulación de la Expresión Génica , Adenina/química , Adenina/metabolismoRESUMEN
Electrocatalytic oxidation of urea (UOR) is a potential energy-saving hydrogen production technology that can replace oxygen evolution reaction (OER). Therefore, CoSeP/CoP interface catalyst is synthesized on nickel foam using hydrothermal, solvothermal, and in situ template methods. The strong interaction of tailored CoSeP/CoP interface promotes the hydrogen production performance of electrolytic urea. During the hydrogen evolution reaction (HER), the overpotential can reach 33.7 mV at 10 mA cm-2 . The cell voltage can reach 1.36 V at 10 mA cm-2 in the overall urea electrolytic process. Notably, the overall urine electrolysis performance of the catalyst in the human urine medium can reach 1.40 V at 10 mA cm-2 and can exhibit durable cycle stability at 100 mA cm-2 . Density functional theory (DFT) proves that the CoSeP/CoP interface catalyst can better adsorb and stabilize reaction intermediates CO* and NH* on its surface through a strong synergistic effect, thus enhancing the catalytic activity.
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The peritrichous genus Ophrydium is relatively distinctive since its colonies have a gelatinous lorica. In the present work, one morphologically well-described species, Ophrydium crassicaule, was collected from a freshwater habitat in China. Both morphological characters and sequence data for SSU rDNA, ITS1-5.8S-ITS2 region and LSU rDNA were obtained. Morphologically, O. crassicaule is characterized by its elongated vase-shaped zooid, single-layered peristomial lip, dichotomously branched stalk, colony with gelatinous lorica, and infundibular polykinety 3 (P3) containing one short inner row and two long outer rows. Phylogenetic analyses revealed that the genus Ophrydium is monophyletic and nests within the family Vorticellidae. In addition, we briefly revise the nominal congeners for aiding the species identification in future studies.
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Cilióforos , Oligohimenóforos , China , ADN Protozoario/genética , ADN Ribosómico/genética , Filogenia , Especificidad de la EspecieRESUMEN
The class Oligohymenophorea is one of the most diverse assemblage of ciliated protists, which are particularly important in fundamental biological studies including understanding the evolutionary relationships among the lineages. Phylogenetic relationships within the class remain largely elusive, especially within the subclass Peniculia, which contains the long-standing problematic taxa Urocentrum and Paranassula. In the present study, we sequenced the genomes and/or transcriptomes of six non-culturable oligohymenophoreans using single-cell sequencing techniques. Phylogenomic analysis was performed based on expanded taxon sampling of 85 taxa, including 157 nuclear genes encoding 36,953 amino acids. The results indicate that: (1) urocentrids form an independent branch that is sister to the clade formed by Scuticociliatia and Hymenostomatia, which, together with the morphological data, supports the establishment of a new subclass, Urocentria n. subcl., within Oligohymenophorea; (2) phylogenomic analysis and ortholog comparison reveal a close relationship between Paranassula and peniculines, providing corroborative evidence for removing Paranassula from Nassulida and elevating it as an order, Paranassulida, within the subclass Peniculia; (3) based on the phylogenomic analyses and morphological data, we hypothesize that Peritrichia is the earliest diverging clade within Oligohymenophorea while Scuticociliatia and Hymenostomatia share the most common ancestor, followed successively by Urocentria and Peniculia. In addition, stop codon analyses indicate that oligohymenophoreans widely use UGA as the stop codon, while UAR are reassigned to glutamate (peritrichs) or glutamine (others), supporting the evolutionary hypothesis.
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Oligohimenóforos/clasificación , Filogenia , Evolución Biológica , Núcleo Celular/genética , Codón de Terminación , Intrones , Análisis de Secuencia de ADN , TranscriptomaRESUMEN
The morphology and ciliature of a new freshwater ciliate, Frontonia apoacuminata sp. nov., isolated from an artificial pond in Qingdao, PR China, were investigated using live observation and silver staining methods. The main features separating F. apoacuminata sp. nov. from its congeners are as follows: a broad elliptical body that is slightly pointed at the posterior end, four ophryokineties, one or two spherical micronuclei of a 'compact' type, a dorsally positioned contractile vacuole, and peniculi 1-3 each with five kinetosome rows though the left-most two rows in peniculus 3 are extremely shortened (with only two or three kinetosomes each). Additionally, an improved diagnosis of F. acuminata is provided. Phylogenetic analyses based on the small subunit ribosomal RNA (SSU rRNA) gene show that F. apoacuminata sp. nov. clusters with F. atra, F. minuta, F. acuminata and F. terricola. These five species group with Disematostoma, Marituja and Stokesia rather than with other Frontonia species, causing polyphyly of the genus Frontonia.
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Oligohimenóforos , Filogenia , Composición de Base , China , ADN Protozoario/genética , Agua Dulce/parasitología , Oligohimenóforos/clasificación , Oligohimenóforos/aislamiento & purificación , Análisis de Secuencia de ADNRESUMEN
Cluster-based coordination polymers (CCPs) have shown promise as capacitors. To investigate the relativity between capacitor performance and crystal structure, herein, five new CCPs based on organophosphorus Strandberg-type clusters were synthesized via in situ hydrothermal reactions at different pH's, namely, (H2bipy)2[(C6H5PO3)2Mo5O15]·2H2O (1), (H2bipy)1.5[CuI(bipy)(C6H5PO3)2Mo5O15]·H2O (2), H2[CuI2(bipy)2.5(C6H5PO3)2Mo5O15]·2H2O (3), Na2[CuI4CuII(bipy)4(C6H5PO3)2(Mo5O15)2]·15H2O (4), [CuII2(bipy)(H2O)4(C6H5PO3)2Mo5O15] (5) (bipy = 4,4'-bipyridine). Compound 1 is a zero-dimensional monomer, in which the protonated bipy ligands as countercations combine Strandberg-type clusters by hydrogen bonding and π-π interaction forming a supramolecular layer. Compound 2 represents a unique one-dimensional (1D) channel chain structure linked by intermolecular hydrogen bonding and π-π interaction. Compounds 3 and 4 exhibit the first example of an interdigitated architecture based on organophosphorus Strandberg-type clusters [1D + 1D â two-dimensional (2D) for 3 and 2D + 2D â three-dimensional (3D) for 4]. Compound 5 displays a novel (3,4)-connected 3D microporous framework with (81·62) (83·63) topology. Notably, the more complicated structures of compounds 1-5 were obtained with an increase in pH. The isolation of five compounds is beneficial for our systematic understanding of the effect of pH on the assembly of CCPs. Organophosphorus Strandberg-type polyoxometalate clusters were explored as supercapacitor electrode materials for the first time. Compared with other CCPs in this work, compound 5 shows the highest specific capacitance, 160.9 F g-1, at a current density of 2 A g-1, and for favorable cycling stability, after 1000 cycles, the retention rate of the capacitance is 95.6% at 10 A g-1.
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Ampullofolliculina Hadzi, 1951 is a monotypic genus, the only species being A. lageniformis which was first discovered in estuarine habitats in the U.S. and has never been redescribed. In the present study, we investigated the taxonomy and phylogeny of A. lageniformis Hadzi, 1951 based on analyses of a population collected from a brackish wetland in Ningbo, China. The main characteristics of this species are as follows: trophont about 450-700 µm long in vivo with two short, rounded peristomial lobes of equal size; lorica flask-shaped, transparent and smooth with a short, wide neck at the base of which two transparent valves are asymmetrically inserted; cortex with brownish to reddish cortical granules and greenish pigment granules; about 80 somatic kineties evenly arranged; moniliform macronucleus with 4-8 ellipsoidal nodules; swarmer dark green, vermiform in shape, about 200-350 µm long in vivo, with about 60 adoral membranelles and 85 somatic kineties, no mouth nor paroral membrane. Phylogenetic analyses inferred from SSU rDNA sequences show that A. lageniformis is closely related to Folliculina and Eufolliculina which nest within a large clade that comprises five families, i.e. Stentoridae, Blepharismidae, Fabreidae, Maristentoridae, and Folliculinidae.
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Cilióforos/clasificación , China , Cilióforos/citología , Cilióforos/genética , ADN Protozoario/análisis , HumedalesRESUMEN
Reasonable design of cost-effective counter electrode (CE) catalysts for triiodide (I3-) reduction reaction (IRR) by simultaneously combining heteroatom doping and facet engineering is highly desired in iodine-based dye-sensitized solar cells (DSSCs), but really challenging. Herein, the density function theory (DFT) calculations were first conducted to demonstrate that the Fe-doped NiSe (111) showed an appropriate adsorption energy for I3-, increased number of metal active sites, reinforced charge-transfer ability, and strong interaction between 3d states of metal sites and 5p state of I1 atoms in I3-, compared to NiSe (111). Based on this finding, the well-defined Fe-NiSe octahedron with exposed (111) plane (marked as Fe-NiSe (111)) and NiSe octahedron with the same exposed plane (named as NiSe (111)) are controllably synthesized. When the as-prepared Fe-NiSe (111) and NiSe (111) worked as CE catalysts, Fe-NiSe (111) exhibits improved electrochemical performance with higher power conversion efficiency (PCE) than NiSe (111), providing new opportunity to replace precious Pt for DSSCs.
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The morphology and infraciliature of a poorly-known colepid ciliate, Pinacocoleps tesselatus (Kahl, 1930) Foissner et al., 2008, collected from brackish-water biotope (salinity 12 per thousand) in Hangzhou Bay, China, were investigated using live observations and silver impregnations. This species is characterized by its length of 60-85 µm in vivo, ovular shape, two anterior and three posterior spines, 21-25 longitudinal and 11 transverse ciliary rows on average, a macro and micro nucleus, and one terminal contractile vacuole. The key to all known seven Pinacocoleps species is updated. Additionally, we characterized the taxon P. tesselatus via small subunit rRNA gene data. Our phylogenetic analyses performed using both maximum-likelihood and Bayesian methods indicate that P. tesselatus falls into the core assemblage of the family Colepidae.
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Cilióforos/crecimiento & desarrollo , Cilióforos/genética , ADN Ribosómico/genética , Subunidades Ribosómicas Pequeñas/genética , China , Cilióforos/clasificación , Datos de Secuencia Molecular , Filogenia , Análisis de SecuenciaRESUMEN
Specimens of two species of Kinorhyncha, Setaphyes dentatus and S. kielensis, were collected in 1988, 1998, and 2016 at two intertidal sites on the island of Sylt, North Sea, and investigated as preserved material by light microscopy and scanning electron microscopy for their epibionts. One species of Acinetidae (Suctoria), one species of Vaginicolidae (Peritrichia), and two species of bacteria were traced. The most abundant ciliate species with 705 specimens was Trematosoma husselae sp. nov. occurring with 146 specimens on a basibiont, mainly on the ventral side and here especially on segment 1. Cothurnia buetschlii was found as 14 specimens. Trematosoma husselae sp. nov. agreed with T. amphiasci and T. pusilla in the calyciform shape of the lorica and with most species in the general size of the body except for the much larger T. constricta and T. pusilla. The new species could be distinguished from T. amphiasci, T. complatana, T. constricta, T. falcata, T. ovata, and T. pusilla by the short length of its stalk and agreed with T. bocqueti and T. rotunda in this character. Cothurnia buetschlii was redescribed for the first time after the descriptions by Zelinka (1914, 1928).
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Cilióforos , Cinetofragminóforos , Oligohimenóforos , Animales , Mar del Norte , AlemaniaRESUMEN
Ciliated protists represent one of the most primitive and diverse lineages of eukaryotes, with nuclear dimorphism, a distinctive sexual process (conjugation), and extensive genome rearrangements. Among divergent ciliate lineages, the peritrich order Sessilida includes members with a colonial lifestyle, which may hint to an independent evolutionary attempt for multicellularity, although they are still single-celled organisms. To date, the evolution and phylogeny of this group are still far from clear, in part due to the paucity of molecular and/or morphological data for many taxa. In this study, we extend taxon sampling of a loricate group of sessilids by obtaining 69 new rDNA (SSU rDNA, ITS1-5.8S rDNA-ITS2, and LSU rDNA) sequences from 20 well-characterized representative species and analyze the phylogenetic relationships within Sessilida. The main findings are: (i) the genera Rhabdostyla and Campanella each represents a unique taxon at family level, supporting the establishment of two new families, i.e., Rhabdostylidae n. fam. and Campanellidae n. fam., respectively, the former being sister to a morphologically heterogeneous clade comprising Astylozoidae and several incertae sedis species and the latter occupying the basal position within the Sessilida clade; (ii) the structure of infundibular polykinety 3 is likely to be a phylogenetically informative character for resolving evolutionary relationships among sessilids; (iii) differences between sparsely and the densely arranged silverline systems could be a suprageneric taxonomic character; (iv) the monophyly of Vaginicolidae is confirmed, which is consistent with its specialized morphology, i.e., the possession of a typical peritrich lorica which might be an apomorphy for this group; (v) within Vaginicolidae, the monotypic Cothurniopsis sensu Stokes, 1893 is a synonym of Cothurnia Ehrenberg, 1831, and a new combination is created, i.e., Cothurnia valvata nov. comb.; (vi) Vaginicola sensu lato comprises at least two distinctly divergent clades, one affiliated with Thuricola and the other with a systematically puzzling clade represented by Vaginicola tincta.
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Cilióforos , Oligohimenóforos , Humanos , Filogenia , Cilióforos/genética , Oligohimenóforos/genética , ADN Ribosómico/genética , Cognición , Análisis de Secuencia de ADNRESUMEN
During a study on the diversity of ciliated protists in Lake Weishan Wetland, the largest wetland in northern China, four epibiotic sessilid peritrichs were isolated from aquatic host animals. Two of them, i.e., Epistylis cambari Kellicott, 1885 and Epistylis lwoffi Fauré-Fremiet, 1943, were known species whereas the other two, i.e., Parapiosoma typicum gen. nov., sp. nov. and Orborhabdostyla gracilis sp. nov., are new to science. The new genus Parapiosoma gen. nov. is characterized by its branched non-contractile stalk, everted peristomial lip, obconical macronucleus and transverse silverlines. Two species are assigned to the new genus, namely Parapiosoma typicum sp. nov. and Parapiosoma gasterostei (Fauré-Fremiet, 1905) comb. nov. Morphologically, P. typicum sp. nov. is recognized by its goblet-shaped zooids, single-layered peristomial lip, dichotomously branched stalk, and infundibular polykinety 3 (P3) containing three equal-length rows. Orborhabdostyla gracilis sp. nov. is characterized by its slender zooid, curved macronucleus, and three equal-length rows in infundibular P3. Improved diagnoses and redescriptions of E. cambari and E. lwoffi are provided including, for the first time, data on the ciliature of E. cambari. Phylogenetic analyses based on SSU rDNA, ITS1-5.8S rDNA -ITS2, and LSU rDNA sequence data strongly support the assertion that the family Epistylididae comprises morphospecies with different evolutionary lineages and indicate that Parapiosoma gen. nov. may represent a new taxon at family level.
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Two colonial sessilid peritrichs, Epistylis qingdaoensis n. sp. and Carchesium cyclopidarum Nenninger, 1948, were isolated from a marine crustacean and a freshwater mayfly, respectively. Morphological characters for each species were revealed by in vivo observations and silver staining methods. Epistylis qingdaoensis n. sp. is characterized by the apperance of the colony which is up to 250 µm high and usually contains fewer than eight zooids, the single-layered peristomial lip, the conspicuously conical peristomial disc, and the structure of infundibular polykinety 3 which comprises three isometric ciliary rows. Carchesium cyclopidarum is recognized by the colony height of about 600 µm, the small zooid size of 35-50 × 20-30 µm, and the low number of silverlines. Phylogenetic analyses based on small subunit ribosomal DNA sequences were performed to reveal their evolutionary relationships. Surprisingly, neither species clustered with its congeners. Epistylis qingdaoensis n. sp. nested within a clade of Zoothamnium species that was sister to a clade comprising core Epistylis species and several Zoothamnium species. Carchesium cyclopidarum nested within a clade comprising solitary peritrichs and was distantly related to the type species of Carchesium, C. polypinum. These findings imply for the first time that Carchesium is non-monophyletic.
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Cilióforos , Ephemeroptera , Oligohimenóforos , Animales , Filogenia , Ephemeroptera/genética , ADN Ribosómico/genética , ChinaRESUMEN
During an investigation of parasitic ciliates in northern China, two Trichodina species, T. acuta Lom, 1970 and T. nigra Lom, 1960, were isolated from the freshwater fish Cyprinus carpio Linnaeus, 1758. The morphology of each species was investigated based on dry silver nitrate-stained specimens. In addition, the molecular phylogeny of each was analyzed based on small subunit ribosomal DNA (SSU rDNA) sequence data. Trichodina acuta can be distinguished from its congeners by the undefined periphery of the central circle, the distinct gap between the rays and the central circle, and the distinctly sickle-shaped blades. Trichodina nigra is a cosmopolitan ciliate and is characterized by its densely linked denticles, broad, rounded spatula-shaped blades, robust central parts, and well developed rays. Phylogenetic analyses revealed that T. acuta and T. nigra nest within different clades, supporting the assertion that the GC content of SSU rDNA sequences could reflect evolutionary relationships among Trichodina species.
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Carpas , Infecciones por Cilióforos/veterinaria , Enfermedades de los Peces/epidemiología , Oligohimenóforos/clasificación , Animales , China/epidemiología , Infecciones por Cilióforos/epidemiología , Infecciones por Cilióforos/parasitología , Enfermedades de los Peces/parasitología , Oligohimenóforos/citología , Oligohimenóforos/genética , Oligohimenóforos/aislamiento & purificación , Filogenia , PrevalenciaRESUMEN
The ciliate genus Pleuronema comprises approximately 30 nominal species and has been reported in freshwater, brackish water, and marine habitats. Nevertheless, recent studies have indicated that there might be a large undiscovered species diversity. In the present work, four new Pleuronema species, namely P. foissneri sp. nov., P. parasmalli sp. nov., P. parasalmastra sp. nov., and P. paraorientale sp. nov., collected from Shenzhen, southern China, was investigated using taxonomic methods. The diagnosis, description, comparisons with morphologically related species and detailed morphometric data are supplied for each. The small subunit ribosomal RNA (SSU rRNA) gene of the four new species is sequenced and their molecular phylogeny is analyzed. The SSU rRNA gene tree shows that Pleuronema is polyphyletic comprising several separate clades. All four new species cluster consistently with P. orientale KF206429, P. puytoraci KF840520 and P. setigerum FJ848874 within the core Pleuronematidae + Peniculistomatidae clade. Phylogenies of Pleuronematidae-related taxa are also discussed. Supplementary Information: The online version contains supplementary material available at 10.1007/s42995-022-00130-5.
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Three epibiotic Epistylis species, i.e., Epistylis weishanensis sp. nov., Epistylis daphniae Fauré-Fremiet, 1905, and Epistylis pygmaeum (Ehrenberg, 1838) Foissner et al., 1999, were investigated based on their living morphology, infraciliature, and small subunit (SSU) rDNA sequence data. Epistylis weishanensis sp. nov. is characterized by its double-layered peristomial lip, contractile vacuole located on the dorsal wall of the infundibulum, infundibular polykinety 3 (P3) composed of three equal-length rows that terminate above infundibular polykinety 1 (P1), 50-62 silverlines between the peristome and the trochal band, and about 30 silverlines between the trochal band and the scopula. Based on previous and newly obtained data for E. daphniae and E. pygmaeum, improved diagnoses and redescriptions are provided including, for the first time, data on their infraciliature. Phylogenetic analyses reveal that all three species do not group within the major clade of Epistylis, supporting the assertion that the genus Epistylis should be an assemblage of morphospecies and therefore needs to be revised.
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Cilióforos , Oligohimenóforos , Lagos , Filogenia , Humedales , Especificidad de la Especie , Cilióforos/genética , ADN Ribosómico/genéticaRESUMEN
Ciliates are core components of the structure of and function of aquatic microbial food webs. They play an essential role in the energy flow and material circulation within aquatic ecosystems. However, studies on the taxonomy and biodiversity of freshwater ciliates, especially those in wetlands in China are limited. To address this issue, a project to investigate the freshwater ciliates of the Lake Weishan Wetland, Shandong Province, commenced in 2019. Here, we summarize our findings to date on the diversity of ciliates. A total of 187 ciliate species have been found, 94 of which are identified to species-level, 87 to genus-level, and six to family-level. These species show a high morphological diversity and represent five classes, i.e., Heterotrichea, Litostomatea, Prostomatea, Oligohymenophorea, and Spirotrichea. The largest number of species documented are oligohymenophoreans. A comprehensive database of these ciliates, including morphological data, gene sequences, microscope slide specimens and a DNA bank, has been established. In the present study, we provide an annotated checklist of retrieved ciliates as well as information on the sequences of published species. Most of these species are recorded in China for the first time and more than 20% are tentatively identified as new to science. Additionally, an investigation of environmental DNA revealed that the ciliate species diversity in Lake Weishan Wetland is higher than previously supposed. Supplementary Information: The online version contains supplementary material available at 10.1007/s42995-022-00154-x.
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During faunal studies of psammophilic ciliates along the coast of Qingdao, China, several marine karyorelictean species were isolated. Among them, four species within the genus Remanella were investigated, including two species new to science: i.e., R. rugosa, Remanella elongata sp. nov., Remanella aposinica sp. nov., and R. unicorpusculata. Remanella rugosa has been reported several times, but this study is the first to provide detailed morphological characters and phylogenetics. Remanella elongata sp. nov. can be distinguished from its congeners by the presence of complex cortical granules, fewer macronuclei, and longer body size. Remanella aposinica sp. nov. differs from its congeners by having 14-17 right lateral ciliary rows and 24-37 dikinetids of intrabuccal kinety. Poorly known Remanella rugosa var. unicorpusculata (Kahl, 1933) Foissner, 1996 should be elevated from subspecies to species level, Remanella unicorpusculata (Foissner, 1996) stat. nov., based on detailed redescriptions with statistical data, living morphology, infraciliature, and species definitions. Small subunit (SSU) rDNA was sequenced for the four species, and phylogenetic analysis revealed that all known taxa in Remanella formed the outline branch to the genus Loxodes with moderate to high bootstrap support among Remanella lineages.
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Cilióforos , Animales , China , Cilióforos/clasificación , Cilióforos/genética , ADN Ribosómico/genética , FilogeniaRESUMEN
Members of the genus Paradileptus are apex predators in microbial food webs. They are often encountered in freshwater biotopes and have been used in research on water quality monitoring and ecology. Nevertheless, our understanding of the biodiversity of Paradileptus, especially its ecological and genetic diversities, is very poor which hinders our ability to understand the ecosystem services it provides. The present study gives a detailed account of two Chinese populations of Paradileptus elephantinus and P. conicus including their living morphology, infraciliature, and molecular phylogenies based on 18S, 5.8S, and ITS ribosomal DNA sequences. The phylogenetic relationships between these two species and other rhynchostomatians are investigated. We also explore the potential contribution of differentiation of the proboscis (e.g., extrusomes, dorsal brush, and differentiated kineties) to niche partitioning and speciation in Paradileptus. The global distribution of Paradileptus is summarized based on published data. Finally, a key to the identification of the valid species of Paradileptus is provided.
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The peritrich genus Epistylis is speciose, however many species lack complete morphological description based on modern criteria and/or molecular data. In the present study, one new species, i.e., E. foissneri n. sp., and two morphologically similar species, i.e., E. hentscheli Kahl, 1935 and E. vaginula Stokes, 1884, collected from freshwater habitats in China, were studied. Epistylis foissneri n. sp. is characterized by its extremely slender zooids encased in a gelatinous sheath, symmetrically dichotomously branched stalk, trochal band located at mid-body, contractile vacuole located on dorsal wall of infundibulum, infundibular polykinety 3 (P3) composed of three equal-length rows that terminate above infundibular polykinety 1 (P1), 105-110 silverlines between the peristome and the trochal band, and about 110 silverlines between the trochal band and the scopula. Epistylis hentscheli is characterized by its asymmetric pyriform zooids (average length ca. 160 µm in vivo), dichotomously branched stalk with transverse striations on the surface of the upper portion, P3 three-rowed and terminating slightly above P1, 60-75 silverlines between the peristome and the trochal band, and 55-90 silverlines between the trochal band and the scopula. Epistylis vaginula is characterized by its elongated body shape (about 100 µm in length in vivo), dichotomously branched and smooth stalk, P3 three-rowed and terminating above P1, 80-100 silverlines between the peristome and the trochal band, and 45-80 silverlines between the trochal band and the scopula. The small subunit ribosomal DNA gene (SSU rDNA) of these three species was sequenced and supported the validity of each. Phylogenetic analyses based on SSU rDNA sequence data revealed that all three morphospecies group with other congeners within the major clade of Epistylis.