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 impreg...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 um×70- 80 um, 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.展开更多
The sporadotrichid ciliates are an especially diverse group. A number of investigators have studied the morphological, morphogenetic, and molecular relationships among members of this group. Despite this, a consistent...The sporadotrichid ciliates are an especially diverse group. A number of investigators have studied the morphological, morphogenetic, and molecular relationships among members of this group. Despite this, a consistent classification is still lacking and several important questions about the phylogenetic relationships within this group remain unsolved. To improve our understanding of these relationships, we constructed phylogenetic trees using the nucleotide sequences of the small-subunit rRNA (SSrRNA) gene and amino acid sequences of actin I and α-tubulin. Analyses of SSrRNA gene sequences indicated that: 1) the Sporadotrichida sensu Lynn (2008) and the Oxytrichidae are polyphyletic; 2) the Uroleptus species, which are classified to urostylids, formed a sister group with the oxytrichids; 3) Halteria grandinella, which is grouped morphologically with oligotrich species, clustered within the oxytrichids. These results are congruent with previous studies based on SSrRNA gene sequences. However, the amino acid sequences of actin I and α-tubulin yielded different topologies. The main results are: 1) in all phylogenetic trees, the genus Oxytricha was paraphyletic; 2) Uroleptus was sister to a subset of Urostyla and Holosticha, albeit with low supporting values; 3) Halteria grandinella was separated distantly from the Oxytrichidae in trees inferred from actin I amino acid sequences but clustered with oligotrichids in the α-tubulin analysis. The inconsistency among the trees inferred from these different molecular markers may be caused by rapidly accumulated genetic characterizations of ciliates. Further studies with additional molecular markers and sampling of more taxa are expected to better address the relationships among sporadotrichids.展开更多
Prostomates and haptorians are two basal groups of ciliates with limited morphological characteristics available for tax- onomy. Morphologically, the structures used to identify prostomates and haptorians are similar ...Prostomates and haptorians are two basal groups of ciliates with limited morphological characteristics available for tax- onomy. Morphologically, the structures used to identify prostomates and haptorians are similar or even identical, which generate heavy taxonomic and phylogenetic confusion. In present work, phylogenetic positions lineage of two rare genera, Plagiopogon and Askenasia, were investigated. Three genes including small subunit ribosomal RNA gene （hereafter SSU rDNA）, internal transcribed spacer region （ITS region）, and large subunit ribosomal RNA gene （LSU rDNA） were analyzed, 10 new sequences five species each. Our findings included 1） class Prostomatea and order Haptorida are multiphyletic; 2） it may not be appropriate to place order Cyclotriehiida in subclass Haptoria, and the systematic lineage of order Cyclotrichiida needs to be verified further; 3） genus Plagio- pogon branches consistently within a clade covering most prostomes and is basal of clade Colepidae, implying its close lineage to Prostomatea; and 4） Askenasia is phylogenetically distant from the subclass Haptoria but close to classes Prostomatea, Plagiopylea and Oligohymenophorea. We supposed that the toxicyst of Askenasia may be close to taxa of prostomes instead of haptorians, and the dorsal brush is a more typical morphological characteristics of haptorians than toxicysts.展开更多
Gene sequence-based genealogies of scuticociliates are different from those produced by morphological analyses.For this reason,11 representative scuticociliates and two ambiguously related genera were chosen to test t...Gene sequence-based genealogies of scuticociliates are different from those produced by morphological analyses.For this reason,11 representative scuticociliates and two ambiguously related genera were chosen to test the ability of combined phylogenetic analyses using both gene sequences and morphological/morphogenetic characteristics.Analyses of both the SSrRNA gene sequences and the combined datasets revealed a consistent branching pattern.While the terminal branches and the order level relationships were generally well resolved,the family level relationships remain unresolved.However,two other trees based on ITS1-5.8S-ITS2 region sequences and morphological/morphogenetic characters showed limited information,due to a lack of informative sites in these two datasets.Our data suggest,however,that the combined analysis of morphological/morphogenetic characters and gene sequences did produce some changes to the phylogenetic estimates of this group.展开更多
Pleurostomatid ciliates,as a highly diverse and widely distributed unicellular eukaryote group,play a crucial role in the cycling of nutrients and energy in microbial food webs.However,research on pleurostomatids rema...Pleurostomatid ciliates,as a highly diverse and widely distributed unicellular eukaryote group,play a crucial role in the cycling of nutrients and energy in microbial food webs.However,research on pleurostomatids remains insufficient,resulting in a paucity of molecular information and substantial gaps in knowledge of their phylogenetic relationships.In recent years,we investigated pleurostomatid diversity in various Chinese habitats,including their systematic relationships and taxonomic circumscriptions,which were comprehensively analyzed using an integrative morphomolecular approach.Results revealed that:(1)pleurostomatids can be categorized into two suborders,Protolitonotina subord.nov.and Amphileptina Jankowski,1967;(2)Protolitonotina subord.nov.represents the ancestral pleurostomatid group and includes two genera,Protolitonotus and Heterolitonotus gen.nov.,characterized by right kineties progressively shortened along rightmost full kineties and absence of a left dorsolateral kinety;(3)Heterolitonotus gen.nov.represents an orphan lineage and is defined by an oral slit extending to its dorsal margin;(4)“Protolitonotus clampi”does not group with congeners but instead represents an orphan lineage,thus Novilitonotus gen.nov.is established to which P.clampi is transferred as Novilitonotus clampi comb.nov.;(5)three new species,Apoamphileptus paraclaparedii sp.nov.,Heterolitonotus rex gen.nov.,sp.nov.,and Loxophyllum apohelus sp.nov.,are described;and(6)helices 21es6a to 21es6d within the V4 region of small subunit ribosomal RNA(SSU rRNA)may serve as a useful tool for discriminating pleurostomatids.The evolutionary relationships among all main lineages of pleurostomatids are discussed and a key to the identification of pleurostomatid genera is provided.展开更多
Determining and comparing mitochondrial genomes(mitogenomes)are essential for assessing the diversity and evolution of mitochondria.Ciliates are ancient and diverse unicellular eukaryotes,and thus are ideal models for...Determining and comparing mitochondrial genomes(mitogenomes)are essential for assessing the diversity and evolution of mitochondria.Ciliates are ancient and diverse unicellular eukaryotes,and thus are ideal models for elucidating the early evolution of mitochondria.Here,we report on six new mitogenomes of spirotrichs,a dominant ciliate group,and perform comparative analyses on 12 representative species.We show that:(1)the mitogenomes of spirotrichs are linear structures with high A+T contents(61.12-81.16%),bidirectional transcription,and extensive synteny(except for the nad5,ccmf and cob genes in Euplotia);(2)the non-split of NADH dehydrogenase subunit 2 gene(nad2)is a plesiomorphy of ciliates,whereas it has evolved into a split gene in Spirotrichea(apart from Euplotes taxa),Oligohymenophorea,and Armophorea;(3)the number of small subunit ribosomal proteins(rps)encoded in mitogenomes increases in the later branching classes of ciliates,whereas rps8 shows a loss trend during the evolution of Euplotes taxa;(4)the mitogenomes of spirotrichs exhibit A/T codon bias at the third position,and the codon bias is mainly due to DNA mutation in oligotrichs,hypotrichs and Diophrys appendiculata;(5)the phylogenetic position of D.appendiculata is unstable and controversial based on both phylogenetic analyses and mitogenome evidence.In summary,we investigated the mitogenome diversity of spirotrichs and broadened our understanding of the evolution of mitochondria in ciliates.展开更多
Scuticociliatia is one of the most species-rich subclasses in the phylum Ciliophora.The evolutionary relationships among Scuticociliatia groups have long been very unclear due to the homogeneity of morphology and insu...Scuticociliatia is one of the most species-rich subclasses in the phylum Ciliophora.The evolutionary relationships among Scuticociliatia groups have long been very unclear due to the homogeneity of morphology and insufficiency of molecular data.With morphological and multi-gene-based molecular data presented here,the evolutionary phylogeny of several Scuticocili-atia taxa that were hitherto especially poorly defined is analyzed and discussed.The results indicate:(1)all scuticociliates cluster into two well supported and one poorly supported group,representing three order-level taxa;(2)with the support of both morphological and molecular data,a new family Homalogastridae fam.nov.is proposed in the order Philasterida;(3)Parauronema is formally transferred to Uronematidae and Potomacus is treated as incertae sedis in the order Philasterida,therefore Parauronematidae is proposed to be a junior synonym of Uronematidae;(4)the genus Madsenia and the species Parauronema longum and Pseudocyclidium longum are treated as incertae sedis,while the genus Protophyra should be maintained in the family Ancistridae.In addition,the putative secondary structure of internal transcribed spacer 2(ITS2)of representative taxa from the three orders of Scuticociliatia are analyzed,and consensus structures and nucleotide composi-tion in each order are exhibited.展开更多
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 tax...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.展开更多
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 ...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 lwof 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.lwof are provided including,for the frst 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 diferent evolutionary lineages and indicate that Parapiosoma gen.nov.may represent a new taxon at family level.展开更多
The subclass Peritrichia,containing two orders Sessilida and Mobilida,is a major group of ciliates with worldwide distribution and high species diversity.Several studies have investigated the phylogeny of peritrichs;h...The subclass Peritrichia,containing two orders Sessilida and Mobilida,is a major group of ciliates with worldwide distribution and high species diversity.Several studies have investigated the phylogeny of peritrichs;however,the evolutionary relationships and classification of some families and genera within the Sessilida remain unclear.In the present study,we isolated and identified 22 peritrich populations representing four families and six genera and obtained 64 rDNA sequences to perform phylogenetic analyses and assess their systematic relationships.Ancestral character reconstruction was also carried out to infer evolutionary routes within the Sessilida.The results indicate:(1)family Vaginicolidae is monophyletic and acquisition of the typical peritrich lorica represents a single evolutionary divergence;(2)core epistylidids evolved from a Zoothamnium-like ancestor and experienced spasmoneme loss during evolution;(3)Campanella clusters with species in the basal clade and shows stable morphological differences with other epistylidids,supporting its assignment to a separate family;(4)the structure of the peristomial lip may be a genus-level character rather than a diagnostic character for discriminating Epistylididae and Operculariidae,thus a redefinition of Operculariidae should be carried out when more species have been investigated;(5)some characters,such as lifestyle(solitary or colonial),spasmoneme and living habit(sessile or free-swimming),evolved repeatedly among sessilids indicating that species with non-contractile stalks or that are free-swimming have multiple evolutionary routes and might derive from any sessilid lineage without a lorica.The close phylogenetic relationships of some morphologically distinct sessilids imply that the diagnoses of some genera and families should be improved.展开更多
Ciliated protists are highly differentiated unicellular eukaryotes that possess special sexual processes(conjugation and autogamy)that rely on their unique nuclear dimorphism,i.e.,the presence of both a germline micro...Ciliated protists are highly differentiated unicellular eukaryotes that possess special sexual processes(conjugation and autogamy)that rely on their unique nuclear dimorphism,i.e.,the presence of both a germline micronucleus(MIC)and a somatic macronucleus(MAC)in a single cell.The sexual processes show a high diversity in different ciliates.To better understand the differentiation and evolution of sexual processes in closely related species,we investigated the nuclear events during conjugation in Paramecium jenningsi strain GZ,a poorly studied close relative of the well-known P.aurelia complex.The main results include:(1)the conjugation process takes about 48 h,including three prezygotic divisions(meiosis I,II,and mitosis)and three postzygotic divisions;(2)the MICs are dominated by the“parachute”phase at the prophase of meiosis I;(3)after meiosis II,a variable number of nuclei undergo the third prezygotic division,and the two products near the paroral cone become the genetically identical migratory and stationary pronuclei;(4)the synkaryon divides three times to form the MIC and the MAC anlagen,but only one nuclear product of the first postzygotic division completes the next two divisions;and(5)an extra cell division is required to complete the last step of conjugation,during which two MIC anlagen undergo mitotic division while two MAC anlagen are distributed between the daughter cells without division.The comparison of the nuclear events during conjugation in representatives of the class Oligohymenophorea reveals that usually there are three prezygotic divisions and a variable number of postzygotic divisions.However,the number of selected and differentiated nuclei after each division differs among species.This study provided a new model ciliate for further investigations of nuclear selection and differentiation as well as nuclear morphology during meiosis.展开更多
Ciliates in the subclass Hypotrichia have long been difficult to classify as they are one of the most polymorphic and highly differentiated groups,leading to their systematics remaining unresolved.Phylogenetic relatio...Ciliates in the subclass Hypotrichia have long been difficult to classify as they are one of the most polymorphic and highly differentiated groups,leading to their systematics remaining unresolved.Phylogenetic relationships within the hypotrich family Strongylidiidae have been ambiguous due to discordance between the morphological and genetic data.In this study,a new strongylidiid genus Heterouroleptus is established,mainly based on the novel mode of origin of the ventral cirral rows:left ventral cirral row(LVR)originates from frontal-ventral-transverse cirral anlagen(FVTA)Ⅲ(anterior portion),IV(middle portion),and V(rear portion);right ventral cirral row comes from the entire FVTA VI.A new species,Hetero-uroleptus weishanensis gen.nov.,sp.nov.,is investigated along with the morphometric and molecular data from a population of Strongylidium wuhanense.Eight new sequences and nuclear gene markers(single-gene and multi-gene)are provided to analyze the phylogenetic relationships of strongylidiids,with the COI gene utilized to uncover further genetic information at species level and below.The results reveal that:(1)Strongylidiidae is monophyletic and has a close relationship with Dorsomarginalia;(2)Heterouroleptus gen.nov.forms a clade that is sister to all the other strongylidiids;(3)Hemiamphisiella Foissner,1988 and Pseudouroleptus Hemberger,1985 should not be synonyms,and both genera should be subdivided due to their variable morphological characteristics;(4)LVR originating from three anlagen is a plesiomorphy of Strongylidiidae.The discovery of the origin of the LVR not only contributes to the establishment of the genus Heterouroleptus,but also helps to improve the diagnosis of the family Strongylidiidae.展开更多
Psammophillic ciliates are an integral part of the foodweb despite being underrepresented in terms of molecular phylogeny and modern taxonomy.To investigate the karyorelictean group,sampling was conducted in interstit...Psammophillic ciliates are an integral part of the foodweb despite being underrepresented in terms of molecular phylogeny and modern taxonomy.To investigate the karyorelictean group,sampling was conducted in interstitial marine habitats in China for ciliates living between the sand grains,resulting in an examination of the families Cryptopharyngidae Jankowski,1980 and Kentrophoridae Jankowski,1980.Three species,i.e.,Cryptopharynx setigerus Kahl,1928,Kentrophoros fasciolatus(Sauerbrey,1928)Foissner,1995 and K.fistulosus(Fauré-Fremiet,1950)Foissner,1995,are clearly recognized as being cosmopolitan,while other species await further recording.Phylogenetic analyses were carried out based on updated data.These revealed that the families Cryptopharyngidae and Kentrophoridae are closely related,and most genera studied are monophyletic,although Cryptopharynx qingdaoensis n.sp.is located within the Kentrophoridae branch.Brief revisions of two genera,namely Cryptopharynx Kahl,1928 and Kentrophoros Sauerbrey,1928,are provided including keys to the iden-tification of nine species belonging to the former and 12 species belonging to the latter.One new genus,Parakentrophoros n.gen.,and one new species,Cryptopharynx qingdaoensis n.sp.,are described and a new combination,Parakentrophoros canalis(Wright,1982)n.comb.,is established.Finally,it appears that the subapical oral apparatus undergoes a gradual degeneration process from Cryptopharyngidae to Kentrophoridae.展开更多
In the aquatic microbial food web,scuticociliates are diverse and predominant in almost all kinds of biotopes while extremely confused regarding their taxonomy and systematic relationships within the subclass Scuticoc...In the aquatic microbial food web,scuticociliates are diverse and predominant in almost all kinds of biotopes while extremely confused regarding their taxonomy and systematic relationships within the subclass Scuticociliatia.Here we provide detailed descriptions of two new and one known species,Glauconema sinica sp.nov.,Pleuronema parasetigerum sp.nov.,and Histiobalantium natans viridis,isolated from a freshwater wetland in northern China,along with their molecular phylogeny based on SSU rRNA gene sequences.Our results show:(1)both molecular and morphological data strongly support that the isolated lineage containing the genera Glauconema,Miamiensis,Paramesanophrys,and Anophryoides should be identified as a new taxon at the family level in the order Philasterida;hence,a new family,Glauconematidae fam.nov.,is established.This new family is mainly characterized by the polymorphic life cycle of its members(macrostome and microstome stages);the trophont(or macrostome)has closely spaced membranelles 1–3,whereas in the tomite(or microstome)membranelle 1 is distant from membranelle 2.(2)Phylogenetic analyses using novel data for these species revealed that all three cluster with their congeners,supporting the validity of the genera to which they belong.Molecular information also supports the monophyly of the two main scuticociliate orders Pleuronematida and Philasterida.展开更多
基金Supported by the National Natural Science Foundation of China(Nos.41006086,31272285)the Natural Science Foundation of Zhejiang Province(No.LY13C040005)+1 种基金the King Saud University,Deanship of Scientific Research,Research Group Project(No.RGP-VPP-083)the K. C. Wong Magna Fund in Ningbo University
文摘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 um×70- 80 um, 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.
基金Supported by the National Natural Science Foundation of China (No. 30870264, 40976075)a grant from the Center of Excellence in Biodiversity, King Saud Universitya Marie Curie Incoming International Fellowship within the 7th European Community Framework Programme
文摘The sporadotrichid ciliates are an especially diverse group. A number of investigators have studied the morphological, morphogenetic, and molecular relationships among members of this group. Despite this, a consistent classification is still lacking and several important questions about the phylogenetic relationships within this group remain unsolved. To improve our understanding of these relationships, we constructed phylogenetic trees using the nucleotide sequences of the small-subunit rRNA (SSrRNA) gene and amino acid sequences of actin I and α-tubulin. Analyses of SSrRNA gene sequences indicated that: 1) the Sporadotrichida sensu Lynn (2008) and the Oxytrichidae are polyphyletic; 2) the Uroleptus species, which are classified to urostylids, formed a sister group with the oxytrichids; 3) Halteria grandinella, which is grouped morphologically with oligotrich species, clustered within the oxytrichids. These results are congruent with previous studies based on SSrRNA gene sequences. However, the amino acid sequences of actin I and α-tubulin yielded different topologies. The main results are: 1) in all phylogenetic trees, the genus Oxytricha was paraphyletic; 2) Uroleptus was sister to a subset of Urostyla and Holosticha, albeit with low supporting values; 3) Halteria grandinella was separated distantly from the Oxytrichidae in trees inferred from actin I amino acid sequences but clustered with oligotrichids in the α-tubulin analysis. The inconsistency among the trees inferred from these different molecular markers may be caused by rapidly accumulated genetic characterizations of ciliates. Further studies with additional molecular markers and sampling of more taxa are expected to better address the relationships among sporadotrichids.
基金supported by the National Natural Science Foundation of China(Nos.31222050,41376141,3112041,and 31471973)the international research projects from King Saud University(Nos.RGP-VPP-083,IRG14-22)
文摘Prostomates and haptorians are two basal groups of ciliates with limited morphological characteristics available for tax- onomy. Morphologically, the structures used to identify prostomates and haptorians are similar or even identical, which generate heavy taxonomic and phylogenetic confusion. In present work, phylogenetic positions lineage of two rare genera, Plagiopogon and Askenasia, were investigated. Three genes including small subunit ribosomal RNA gene （hereafter SSU rDNA）, internal transcribed spacer region （ITS region）, and large subunit ribosomal RNA gene （LSU rDNA） were analyzed, 10 new sequences five species each. Our findings included 1） class Prostomatea and order Haptorida are multiphyletic; 2） it may not be appropriate to place order Cyclotriehiida in subclass Haptoria, and the systematic lineage of order Cyclotrichiida needs to be verified further; 3） genus Plagio- pogon branches consistently within a clade covering most prostomes and is basal of clade Colepidae, implying its close lineage to Prostomatea; and 4） Askenasia is phylogenetically distant from the subclass Haptoria but close to classes Prostomatea, Plagiopylea and Oligohymenophorea. We supposed that the toxicyst of Askenasia may be close to taxa of prostomes instead of haptorians, and the dorsal brush is a more typical morphological characteristics of haptorians than toxicysts.
基金Supported by the National Natural Science Foundation of China(No.30870280)a grant from the Center of Excellence in Biodiversity,King Saud University,Riyadh,Saudi Arabia
文摘Gene sequence-based genealogies of scuticociliates are different from those produced by morphological analyses.For this reason,11 representative scuticociliates and two ambiguously related genera were chosen to test the ability of combined phylogenetic analyses using both gene sequences and morphological/morphogenetic characteristics.Analyses of both the SSrRNA gene sequences and the combined datasets revealed a consistent branching pattern.While the terminal branches and the order level relationships were generally well resolved,the family level relationships remain unresolved.However,two other trees based on ITS1-5.8S-ITS2 region sequences and morphological/morphogenetic characters showed limited information,due to a lack of informative sites in these two datasets.Our data suggest,however,that the combined analysis of morphological/morphogenetic characters and gene sequences did produce some changes to the phylogenetic estimates of this group.
基金supported by the National Natural Science Foundation of China(32030015,32170533)Researchers Supporting Project Number(RSP2024R10)King Saud University,Riyadh,Saudi Arabia。
文摘Pleurostomatid ciliates,as a highly diverse and widely distributed unicellular eukaryote group,play a crucial role in the cycling of nutrients and energy in microbial food webs.However,research on pleurostomatids remains insufficient,resulting in a paucity of molecular information and substantial gaps in knowledge of their phylogenetic relationships.In recent years,we investigated pleurostomatid diversity in various Chinese habitats,including their systematic relationships and taxonomic circumscriptions,which were comprehensively analyzed using an integrative morphomolecular approach.Results revealed that:(1)pleurostomatids can be categorized into two suborders,Protolitonotina subord.nov.and Amphileptina Jankowski,1967;(2)Protolitonotina subord.nov.represents the ancestral pleurostomatid group and includes two genera,Protolitonotus and Heterolitonotus gen.nov.,characterized by right kineties progressively shortened along rightmost full kineties and absence of a left dorsolateral kinety;(3)Heterolitonotus gen.nov.represents an orphan lineage and is defined by an oral slit extending to its dorsal margin;(4)“Protolitonotus clampi”does not group with congeners but instead represents an orphan lineage,thus Novilitonotus gen.nov.is established to which P.clampi is transferred as Novilitonotus clampi comb.nov.;(5)three new species,Apoamphileptus paraclaparedii sp.nov.,Heterolitonotus rex gen.nov.,sp.nov.,and Loxophyllum apohelus sp.nov.,are described;and(6)helices 21es6a to 21es6d within the V4 region of small subunit ribosomal RNA(SSU rRNA)may serve as a useful tool for discriminating pleurostomatids.The evolutionary relationships among all main lineages of pleurostomatids are discussed and a key to the identification of pleurostomatid genera is provided.
基金supported by the Laoshan Labo-ratory(No.LSKJ202203202)the Natural Science Foundation of China(32030015,32300386,32270558)+2 种基金China Postdoctoral Science Foundation(2022M722019)US National Institutes of Health Grant(P40OD010964)a supporting project(RSP2024R10)at King Saud University,Saudi Arabia.
文摘Determining and comparing mitochondrial genomes(mitogenomes)are essential for assessing the diversity and evolution of mitochondria.Ciliates are ancient and diverse unicellular eukaryotes,and thus are ideal models for elucidating the early evolution of mitochondria.Here,we report on six new mitogenomes of spirotrichs,a dominant ciliate group,and perform comparative analyses on 12 representative species.We show that:(1)the mitogenomes of spirotrichs are linear structures with high A+T contents(61.12-81.16%),bidirectional transcription,and extensive synteny(except for the nad5,ccmf and cob genes in Euplotia);(2)the non-split of NADH dehydrogenase subunit 2 gene(nad2)is a plesiomorphy of ciliates,whereas it has evolved into a split gene in Spirotrichea(apart from Euplotes taxa),Oligohymenophorea,and Armophorea;(3)the number of small subunit ribosomal proteins(rps)encoded in mitogenomes increases in the later branching classes of ciliates,whereas rps8 shows a loss trend during the evolution of Euplotes taxa;(4)the mitogenomes of spirotrichs exhibit A/T codon bias at the third position,and the codon bias is mainly due to DNA mutation in oligotrichs,hypotrichs and Diophrys appendiculata;(5)the phylogenetic position of D.appendiculata is unstable and controversial based on both phylogenetic analyses and mitogenome evidence.In summary,we investigated the mitogenome diversity of spirotrichs and broadened our understanding of the evolution of mitochondria in ciliates.
基金supported by Laoshan Laboratory(No.LSKJ20220320001)the National Natural Science Foundation of China(Project numbers:32030015,32100404,32100382)+2 种基金the Natural Science Foundation of Shandong Province(Project numbers:ZR2021QC045,ZR2021QC104)Young Elite Scientists Sponsorship Program by CAST(Project number:2022QNRC001)a supporting project(Project number:RSP2025R10)at King Saud University,Saudi Arabia.
文摘Scuticociliatia is one of the most species-rich subclasses in the phylum Ciliophora.The evolutionary relationships among Scuticociliatia groups have long been very unclear due to the homogeneity of morphology and insufficiency of molecular data.With morphological and multi-gene-based molecular data presented here,the evolutionary phylogeny of several Scuticocili-atia taxa that were hitherto especially poorly defined is analyzed and discussed.The results indicate:(1)all scuticociliates cluster into two well supported and one poorly supported group,representing three order-level taxa;(2)with the support of both morphological and molecular data,a new family Homalogastridae fam.nov.is proposed in the order Philasterida;(3)Parauronema is formally transferred to Uronematidae and Potomacus is treated as incertae sedis in the order Philasterida,therefore Parauronematidae is proposed to be a junior synonym of Uronematidae;(4)the genus Madsenia and the species Parauronema longum and Pseudocyclidium longum are treated as incertae sedis,while the genus Protophyra should be maintained in the family Ancistridae.In addition,the putative secondary structure of internal transcribed spacer 2(ITS2)of representative taxa from the three orders of Scuticociliatia are analyzed,and consensus structures and nucleotide composi-tion in each order are exhibited.
基金supported by the Laoshan Laboratory(No.LSKJ202203201)the National Natural Science Foundation of China(project numbers:32030015,32000300,31961123002)+1 种基金the China Postdoctoral Science Foundation(project number:2021M703037,2022M711922)the Researchers Supporting Project(Project number RSP2022R10)。
文摘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.
基金This work was supported by the National Natural Science Foundation of China(Project numbers:32030015,32000300)the Natural Science Foundation of Shandong Province(Project number:ZR2021QC104,ZR2022QC096)+1 种基金China Postdoctoral Science Foundation(Project numbers:2021M701993,2022M711922)the King Saud University,Saudi Arabia(Project number RSP2023R10).We sincerely thank the“Weishan Wetland Station”for institutional support.
文摘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 lwof 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.lwof are provided including,for the frst 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 diferent evolutionary lineages and indicate that Parapiosoma gen.nov.may represent a new taxon at family level.
基金supported by the Laoshan Laboratory(No.LSKJ202203201)the National Key Research and Development Program of China(2020YFD0900303)+3 种基金National Natural Science Foundation of China(project numbers:32030015,32000300,32270481,32100382)Hubei Agricultural Sciences and Technology Innovation Center(2021-620-000-001-33)China Postdoctoral Science Foundation Grant(project numbers:2022M711922,2021M701993)the Researchers Supporting Project(Project number RSP2022R10)of King Saud University,Saudi Arabia.
文摘The subclass Peritrichia,containing two orders Sessilida and Mobilida,is a major group of ciliates with worldwide distribution and high species diversity.Several studies have investigated the phylogeny of peritrichs;however,the evolutionary relationships and classification of some families and genera within the Sessilida remain unclear.In the present study,we isolated and identified 22 peritrich populations representing four families and six genera and obtained 64 rDNA sequences to perform phylogenetic analyses and assess their systematic relationships.Ancestral character reconstruction was also carried out to infer evolutionary routes within the Sessilida.The results indicate:(1)family Vaginicolidae is monophyletic and acquisition of the typical peritrich lorica represents a single evolutionary divergence;(2)core epistylidids evolved from a Zoothamnium-like ancestor and experienced spasmoneme loss during evolution;(3)Campanella clusters with species in the basal clade and shows stable morphological differences with other epistylidids,supporting its assignment to a separate family;(4)the structure of the peristomial lip may be a genus-level character rather than a diagnostic character for discriminating Epistylididae and Operculariidae,thus a redefinition of Operculariidae should be carried out when more species have been investigated;(5)some characters,such as lifestyle(solitary or colonial),spasmoneme and living habit(sessile or free-swimming),evolved repeatedly among sessilids indicating that species with non-contractile stalks or that are free-swimming have multiple evolutionary routes and might derive from any sessilid lineage without a lorica.The close phylogenetic relationships of some morphologically distinct sessilids imply that the diagnoses of some genera and families should be improved.
基金supported by the National Natural Science Foundation of China(No.32270539,31961123002)the Natural Science Foundation of Shandong Province(ZR2020JQ13)+1 种基金the Fundamental Research Funds for the Central Universities(202141004)the Researchers Supporting Project Number(RSP2023R10)King Saud University,Riyadh,Saudi Arabia.
文摘Ciliated protists are highly differentiated unicellular eukaryotes that possess special sexual processes(conjugation and autogamy)that rely on their unique nuclear dimorphism,i.e.,the presence of both a germline micronucleus(MIC)and a somatic macronucleus(MAC)in a single cell.The sexual processes show a high diversity in different ciliates.To better understand the differentiation and evolution of sexual processes in closely related species,we investigated the nuclear events during conjugation in Paramecium jenningsi strain GZ,a poorly studied close relative of the well-known P.aurelia complex.The main results include:(1)the conjugation process takes about 48 h,including three prezygotic divisions(meiosis I,II,and mitosis)and three postzygotic divisions;(2)the MICs are dominated by the“parachute”phase at the prophase of meiosis I;(3)after meiosis II,a variable number of nuclei undergo the third prezygotic division,and the two products near the paroral cone become the genetically identical migratory and stationary pronuclei;(4)the synkaryon divides three times to form the MIC and the MAC anlagen,but only one nuclear product of the first postzygotic division completes the next two divisions;and(5)an extra cell division is required to complete the last step of conjugation,during which two MIC anlagen undergo mitotic division while two MAC anlagen are distributed between the daughter cells without division.The comparison of the nuclear events during conjugation in representatives of the class Oligohymenophorea reveals that usually there are three prezygotic divisions and a variable number of postzygotic divisions.However,the number of selected and differentiated nuclei after each division differs among species.This study provided a new model ciliate for further investigations of nuclear selection and differentiation as well as nuclear morphology during meiosis.
基金funded by the Science&Technol-ogy Innovation Project of Laoshan Laboratory(No.LSKJ202203201)National Natural Science Foundation of China(No.32030015,32370475)+1 种基金Researchers Supporting Project(No.RSP2024R10)King Saud University,Riyadh,Saudi ArabiaGuangdong Province Youth Innovative Talent Project 2022(2022KQNCX107).
文摘Ciliates in the subclass Hypotrichia have long been difficult to classify as they are one of the most polymorphic and highly differentiated groups,leading to their systematics remaining unresolved.Phylogenetic relationships within the hypotrich family Strongylidiidae have been ambiguous due to discordance between the morphological and genetic data.In this study,a new strongylidiid genus Heterouroleptus is established,mainly based on the novel mode of origin of the ventral cirral rows:left ventral cirral row(LVR)originates from frontal-ventral-transverse cirral anlagen(FVTA)Ⅲ(anterior portion),IV(middle portion),and V(rear portion);right ventral cirral row comes from the entire FVTA VI.A new species,Hetero-uroleptus weishanensis gen.nov.,sp.nov.,is investigated along with the morphometric and molecular data from a population of Strongylidium wuhanense.Eight new sequences and nuclear gene markers(single-gene and multi-gene)are provided to analyze the phylogenetic relationships of strongylidiids,with the COI gene utilized to uncover further genetic information at species level and below.The results reveal that:(1)Strongylidiidae is monophyletic and has a close relationship with Dorsomarginalia;(2)Heterouroleptus gen.nov.forms a clade that is sister to all the other strongylidiids;(3)Hemiamphisiella Foissner,1988 and Pseudouroleptus Hemberger,1985 should not be synonyms,and both genera should be subdivided due to their variable morphological characteristics;(4)LVR originating from three anlagen is a plesiomorphy of Strongylidiidae.The discovery of the origin of the LVR not only contributes to the establishment of the genus Heterouroleptus,but also helps to improve the diagnosis of the family Strongylidiidae.
基金funded by the Science&Technology Innovation Project of Laoshan Laboratory(No.LSKJ202203201)the National Natural Science Foundation of China(No.32270558,31772431)+1 种基金China Postdoctoral Science Foundation(No.2024M751801)Researchers Supporting Project Number(No.RSP2024R10)King Saud University,Saudi Arabia and Young Taishan Scholar Program of Shandong Province.
文摘Psammophillic ciliates are an integral part of the foodweb despite being underrepresented in terms of molecular phylogeny and modern taxonomy.To investigate the karyorelictean group,sampling was conducted in interstitial marine habitats in China for ciliates living between the sand grains,resulting in an examination of the families Cryptopharyngidae Jankowski,1980 and Kentrophoridae Jankowski,1980.Three species,i.e.,Cryptopharynx setigerus Kahl,1928,Kentrophoros fasciolatus(Sauerbrey,1928)Foissner,1995 and K.fistulosus(Fauré-Fremiet,1950)Foissner,1995,are clearly recognized as being cosmopolitan,while other species await further recording.Phylogenetic analyses were carried out based on updated data.These revealed that the families Cryptopharyngidae and Kentrophoridae are closely related,and most genera studied are monophyletic,although Cryptopharynx qingdaoensis n.sp.is located within the Kentrophoridae branch.Brief revisions of two genera,namely Cryptopharynx Kahl,1928 and Kentrophoros Sauerbrey,1928,are provided including keys to the iden-tification of nine species belonging to the former and 12 species belonging to the latter.One new genus,Parakentrophoros n.gen.,and one new species,Cryptopharynx qingdaoensis n.sp.,are described and a new combination,Parakentrophoros canalis(Wright,1982)n.comb.,is established.Finally,it appears that the subapical oral apparatus undergoes a gradual degeneration process from Cryptopharyngidae to Kentrophoridae.
基金funded by the National Natural Science Foundation of China(Project number:32030015,32100404)the Natural Science Foundation of Shandong Province(Project number:ZR2021QC045)the King Saud University,Saudi Arabia(Project number:RSP2024R7).
文摘In the aquatic microbial food web,scuticociliates are diverse and predominant in almost all kinds of biotopes while extremely confused regarding their taxonomy and systematic relationships within the subclass Scuticociliatia.Here we provide detailed descriptions of two new and one known species,Glauconema sinica sp.nov.,Pleuronema parasetigerum sp.nov.,and Histiobalantium natans viridis,isolated from a freshwater wetland in northern China,along with their molecular phylogeny based on SSU rRNA gene sequences.Our results show:(1)both molecular and morphological data strongly support that the isolated lineage containing the genera Glauconema,Miamiensis,Paramesanophrys,and Anophryoides should be identified as a new taxon at the family level in the order Philasterida;hence,a new family,Glauconematidae fam.nov.,is established.This new family is mainly characterized by the polymorphic life cycle of its members(macrostome and microstome stages);the trophont(or macrostome)has closely spaced membranelles 1–3,whereas in the tomite(or microstome)membranelle 1 is distant from membranelle 2.(2)Phylogenetic analyses using novel data for these species revealed that all three cluster with their congeners,supporting the validity of the genera to which they belong.Molecular information also supports the monophyly of the two main scuticociliate orders Pleuronematida and Philasterida.
