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Zavadska D, Henry N, Auladell A, Berney C, Richter DJ. Diverse patterns of correspondence between protist metabarcodes and protist metagenome-assembled genomes. PLoS One 2024; 19:e0303697. [PMID: 38843225 PMCID: PMC11156365 DOI: 10.1371/journal.pone.0303697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Accepted: 04/29/2024] [Indexed: 06/09/2024] Open
Abstract
Two common approaches to study the composition of environmental protist communities are metabarcoding and metagenomics. Raw metabarcoding data are usually processed into Operational Taxonomic Units (OTUs) or amplicon sequence variants (ASVs) through clustering or denoising approaches, respectively. Analogous approaches are used to assemble metagenomic reads into metagenome-assembled genomes (MAGs). Understanding the correspondence between the data produced by these two approaches can help to integrate information between the datasets and to explain how metabarcoding OTUs and MAGs are related with the underlying biological entities they are hypothesised to represent. MAGs do not contain the commonly used barcoding loci, therefore sequence homology approaches cannot be used to match OTUs and MAGs. We made an attempt to match V9 metabarcoding OTUs from the 18S rRNA gene (V9 OTUs) and MAGs from the Tara Oceans expedition based on the correspondence of their relative abundances across the same set of samples. We evaluated several metrics for detecting correspondence between features in these two datasets and developed controls to filter artefacts of data structure and processing. After selecting the best-performing metrics, ranking the V9 OTU/MAG matches by their proportionality/correlation coefficients and applying a set of selection criteria, we identified candidate matches between V9 OTUs and MAGs. In some cases, V9 OTUs and MAGs could be matched with a one-to-one correspondence, implying that they likely represent the same underlying biological entity. More generally, matches we observed could be classified into 4 scenarios: one V9 OTU matches many MAGs; many V9 OTUs match many MAGs; many V9 OTUs match one MAG; one V9 OTU matches one MAG. Notably, we found some instances in which different OTU-MAG matches from the same taxonomic group were not classified in the same scenario, with all four scenarios possible even within the same taxonomic group, illustrating that factors beyond taxonomic lineage influence the relationship between OTUs and MAGs. Overall, each scenario produces a different interpretation of V9 OTUs, MAGs and how they compare in terms of the genomic and ecological diversity they represent.
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Affiliation(s)
- Daryna Zavadska
- Institut de Biologia Evolutiva (CSIC-Universitat Pompeu Fabra), Barcelona, Spain
| | - Nicolas Henry
- CNRS, FR2424, ABiMS, Station Biologique de Roscoff, Sorbonne Université, Roscoff, France
| | - Adrià Auladell
- Institut de Biologia Evolutiva (CSIC-Universitat Pompeu Fabra), Barcelona, Spain
| | - Cédric Berney
- CNRS, UMR7144, AD2M, Station Biologique de Roscoff, Sorbonne Université, Roscoff, France
| | - Daniel J. Richter
- Institut de Biologia Evolutiva (CSIC-Universitat Pompeu Fabra), Barcelona, Spain
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2
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Gaydukova SA, Moldovan MA, Vallesi A, Heaphy SM, Atkins JF, Gelfand MS, Baranov PV. Nontriplet feature of genetic code in Euplotes ciliates is a result of neutral evolution. Proc Natl Acad Sci U S A 2023; 120:e2221683120. [PMID: 37216548 PMCID: PMC10235951 DOI: 10.1073/pnas.2221683120] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 04/12/2023] [Indexed: 05/24/2023] Open
Abstract
The triplet nature of the genetic code is considered a universal feature of known organisms. However, frequent stop codons at internal mRNA positions in Euplotes ciliates ultimately specify ribosomal frameshifting by one or two nucleotides depending on the context, thus posing a nontriplet feature of the genetic code of these organisms. Here, we sequenced transcriptomes of eight Euplotes species and assessed evolutionary patterns arising at frameshift sites. We show that frameshift sites are currently accumulating more rapidly by genetic drift than they are removed by weak selection. The time needed to reach the mutational equilibrium is several times longer than the age of Euplotes and is expected to occur after a several-fold increase in the frequency of frameshift sites. This suggests that Euplotes are at an early stage of the spread of frameshifting in expression of their genome. In addition, we find the net fitness burden of frameshift sites to be noncritical for the survival of Euplotes. Our results suggest that fundamental genome-wide changes such as a violation of the triplet character of genetic code can be introduced and maintained solely by neutral evolution.
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Affiliation(s)
- Sofya A. Gaydukova
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow199911, Russia
| | - Mikhail A. Moldovan
- A. A. Kharkevich Institute for Information Transmission Problems RAS, Moscow127051, Russia
| | - Adriana Vallesi
- Laboratory of Eukaryotic Microbiology and Animal Biology, School of Biosciences and Veterinary Medicine, University of Camerino, Camerino62032, Italy
| | - Stephen M. Heaphy
- School of Biochemistry and Cell Biology, University College Cork, CorkT12 XF62, Ireland
| | - John F. Atkins
- School of Biochemistry and Cell Biology, University College Cork, CorkT12 XF62, Ireland
- Department of Human Genetics, University of Utah, Salt Lake City, UT84112
| | - Mikhail S. Gelfand
- A. A. Kharkevich Institute for Information Transmission Problems RAS, Moscow127051, Russia
| | - Pavel V. Baranov
- School of Biochemistry and Cell Biology, University College Cork, CorkT12 XF62, Ireland
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3
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Ciliate Morpho-Taxonomy and Practical Considerations before Deploying Metabarcoding to Ciliate Community Diversity Surveys in Urban Receiving Waters. Microorganisms 2022; 10:microorganisms10122512. [PMID: 36557765 PMCID: PMC9787992 DOI: 10.3390/microorganisms10122512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 12/12/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022] Open
Abstract
Disentangling biodiversity and community assembly effects on ecosystem function has always been an important topic in ecological research. The development and application of a DNA metabarcoding method has fundamentally changed the way we describe prokaryotic communities and estimate biodiversity. Compared to prokaryotes (bacteria and archaea), the eukaryotic microbes (unicellular eukaryotes) also fulfill extremely important ecological functions in different ecosystems regarding their intermediate trophic positions. For instance, ciliated microbes (accounting for a substantial portion of the diversity of unicellular eukaryotes) perform pivotal roles in microbial loops and are essential components in different ecosystems, especially in water purification processes. Therefore, the community composition of ciliated species has been widely utilized as a proxy for water quality and biological assessment in urban river ecosystems and WWTPs (wastewater treatment plants). Unfortunately, investigating the dynamic changes and compositions in ciliate communities relies heavily on existing morpho-taxonomical descriptions, which is limited by traditional microscopic approaches. To deal with this dilemma, we discuss the DNA-based taxonomy of ciliates, the relative merits and challenges of deploying its application using DNA metabarcoding for surveys of ciliate community diversity in urban waterbodies, and provide suggestions for minimizing relevant sources of biases in its implementation. We expect that DNA metabarcoding could untangle relationships between community assembly and environmental changes affecting ciliate communities. These analyses and discussions could offer a replicable method in support of the application of evaluating communities of ciliated protozoa as indicators of urban freshwater ecosystems.
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Othman SN, Shin Y, Kim HT, Chuang MF, Bae Y, Hoti J, Zhang Y, Jang Y, Borzée A. Evaluating the efficiency of popular species identification analytical methods, and integrative workflow using morphometry and barcoding bioinformatics for taxonomy and origin of traded cryptic brown frogs. Glob Ecol Conserv 2022. [DOI: 10.1016/j.gecco.2022.e02253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022] Open
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5
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Primary Structure and Coding Genes of Two Pheromones from the Antarctic Psychrophilic Ciliate, Euplotes focardii. Microorganisms 2022; 10:microorganisms10061089. [PMID: 35744607 PMCID: PMC9229436 DOI: 10.3390/microorganisms10061089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 05/14/2022] [Accepted: 05/23/2022] [Indexed: 02/01/2023] Open
Abstract
In ciliates, diffusible cell type-specific pheromones regulate cell growth and mating phenomena acting competitively in both autocrine and heterologous fashion. In Euplotes species, these signaling molecules are represented by species-specific families of structurally homologous small, disulfide-rich proteins, each specified by one of a series of multiple alleles that are inherited without relationships of dominance at the mat-genetic locus of the germinal micronuclear genome, and expressed as individual gene-sized molecules in the somatic macronuclear genome. Here we report the 85-amino acid sequences and the full-length macronuclear nucleotide coding sequences of two pheromones, designated Ef-1 and Ef-2, isolated from the supernatant of a wild-type strain of a psychrophilic species of Euplotes, E. focardii, endemic to Antarctic coastal waters. An overall comparison of the determined E. focardii pheromone and pheromone-gene structures with their homologs from congeneric species provides an initial picture of how an evolutionary increase in the complexity of these structures accompanies Euplotes speciation.
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Melekhin M, Yakovleva Y, Lebedeva N, Nekrasova I, Nikitashina L, Castelli M, Mayén-Estrada R, Romanovich AE, Petroni G, Potekhin A. Cryptic Diversity in Paramecium multimicronucleatum Revealed with a Polyphasic Approach. Microorganisms 2022; 10:microorganisms10050974. [PMID: 35630417 PMCID: PMC9143557 DOI: 10.3390/microorganisms10050974] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 04/01/2022] [Accepted: 05/03/2022] [Indexed: 02/06/2023] Open
Abstract
Paramecium (Ciliophora) systematics is well studied, and about twenty morphological species have been described. The morphological species may include several genetic species. However, molecular phylogenetic analyses revealed that the species diversity within Paramecium could be even higher and has raised a problem of cryptic species whose statuses remain uncertain. In the present study, we provide the morphological and molecular characterization of two novel Paramecium species. While Paramecium lynni n. sp., although morphologically similar to P. multimicronucleatum, is phylogenetically well separated from all other Paramecium species, Paramecium fokini n. sp. appears to be a cryptic sister species to P. multimicronucleatum. The latter two species can be distinguished only by molecular methods. The number and structure of micronuclei, traditionally utilized to discriminate species in Paramecium, vary not only between but also within each of the three studied species and, thus, cannot be considered a reliable feature for species identification. The geographic distribution of the P. multimicronucleatum and P. fokini n. sp. strains do not show defined patterns, still leaving space for a role of the geographic factor in initial speciation in Paramecium. Future findings of new Paramecium species can be predicted from the molecular data, while morphological characteristics appear to be unstable and overlapping at least in some species.
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Affiliation(s)
- Maksim Melekhin
- Faculty of Biology, Saint Petersburg State University, 199034 Saint Petersburg, Russia
- Laboratory of Cellular and Molecular Protistology, Zoological Institute RAS, 199034 Saint Petersburg, Russia
| | - Yulia Yakovleva
- Faculty of Biology, Saint Petersburg State University, 199034 Saint Petersburg, Russia
| | - Natalia Lebedeva
- Centre for Culture Collection of Microorganisms, Saint Petersburg State University, 198504 Saint Petersburg, Russia
| | - Irina Nekrasova
- Faculty of Biology, Saint Petersburg State University, 199034 Saint Petersburg, Russia
| | - Liubov Nikitashina
- Faculty of Biology, Saint Petersburg State University, 199034 Saint Petersburg, Russia
| | - Michele Castelli
- Department of Biology and Biotechnology 'Lazzaro Spallanzani', University of Pavia, 27100 Pavia, Italy
| | - Rosaura Mayén-Estrada
- Laboratorio de Protozoología, Facultad de Ciencias, Universidad Nacional Autónoma de México, Circuito Ext. s/núm. Ciudad Universitaria, Av. Universidad 3000, Coyoacán, Ciudad de Mexico 04510, Mexico
| | - Anna E Romanovich
- Center for Molecular and Cell Technologies, Saint Petersburg State University, 199034 Saint Petersburg, Russia
| | - Giulio Petroni
- Department of Biology, University of Pisa, 56126 Pisa, Italy
| | - Alexey Potekhin
- Faculty of Biology, Saint Petersburg State University, 199034 Saint Petersburg, Russia
- Laboratory of Cellular and Molecular Protistology, Zoological Institute RAS, 199034 Saint Petersburg, Russia
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Xu J, Han J, Su H, Zhu C, Quan Z, Wu L, Yi Z. Diversity Patterns of Protists Are Highly Affected by Methods Disentangling Biological Variants: A Case Study in Oligotrich (s.l.) Ciliates. Microorganisms 2022; 10:913. [PMID: 35630359 PMCID: PMC9147439 DOI: 10.3390/microorganisms10050913] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 04/15/2022] [Accepted: 04/25/2022] [Indexed: 02/05/2023] Open
Abstract
Protists are a dominant group in marine microplankton communities and play important roles in energy flux and nutrient cycling in marine ecosystems. Environmental sequences produced by high-throughput sequencing (HTS) methods are increasingly used for inferring the diversity and distribution patterns of protists. However, studies testing whether methods disentangling biological variants affect the diversity and distribution patterns of protists using field samples are insufficient. Oligotrich (s.l.) ciliates are one group of the abundant and dominant planktonic protists in coastal waters and open oceans. Using oligotrich (s.l.) ciliates in field samples as an example, the present study indicates that DADA2 performs better than SWARM, UNOISE, UPARSE, and UCLUST for inferring diversity patterns of oligotrich (s.l.) ciliates in the Pearl River Estuary and surrounding regions. UPARSE and UNOISE might underestimate species richness. SWARM might not be suitable for the resolution of alpha diversity owing to its rigorous clustering and sensitivity to sequence variations. UCLUST with 99% clustering threshold overestimates species richness, and the beta diversity pattern inferred by DADA2 is more reasonable than that of the other methods. Additionally, salinity is shown to be one of the key factors responsible for variations in the community distribution of ciliates, but infrequent marine-freshwater transitions occurred during evolutionary terms of this group.
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Affiliation(s)
- Jiahui Xu
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, School of Life Science, South China Normal University, Guangzhou 510631, China; (J.X.); (J.H.); (H.S.); (C.Z.); (Z.Q.); (L.W.)
| | - Jianlin Han
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, School of Life Science, South China Normal University, Guangzhou 510631, China; (J.X.); (J.H.); (H.S.); (C.Z.); (Z.Q.); (L.W.)
| | - Hua Su
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, School of Life Science, South China Normal University, Guangzhou 510631, China; (J.X.); (J.H.); (H.S.); (C.Z.); (Z.Q.); (L.W.)
| | - Changyu Zhu
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, School of Life Science, South China Normal University, Guangzhou 510631, China; (J.X.); (J.H.); (H.S.); (C.Z.); (Z.Q.); (L.W.)
- Institute of Evolution & Marine Biodiversity, College of Fisheries, Ocean University of China, Qingdao 266003, China
| | - Zijing Quan
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, School of Life Science, South China Normal University, Guangzhou 510631, China; (J.X.); (J.H.); (H.S.); (C.Z.); (Z.Q.); (L.W.)
| | - Lei Wu
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, School of Life Science, South China Normal University, Guangzhou 510631, China; (J.X.); (J.H.); (H.S.); (C.Z.); (Z.Q.); (L.W.)
| | - Zhenzhen Yi
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, School of Life Science, South China Normal University, Guangzhou 510631, China; (J.X.); (J.H.); (H.S.); (C.Z.); (Z.Q.); (L.W.)
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8
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Wang C, Hu Y, Warren A, Hu X. Genetic Diversity and Phylogeny of the Genus Euplotes (Protozoa, Ciliophora) Revealed by the Mitochondrial CO1 and Nuclear Ribosomal Genes. Microorganisms 2021; 9:microorganisms9112204. [PMID: 34835330 PMCID: PMC8624429 DOI: 10.3390/microorganisms9112204] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 10/03/2021] [Accepted: 10/19/2021] [Indexed: 11/16/2022] Open
Abstract
Nuclear ribosomal and mitochondrial genes have been utilized individually or in combination to identify known species and discriminate closely related species. However, compared with metazoans, genetic diversity within the ciliate order Euplotida is poorly known. The aim of this study is to investigate how much nucleotide sequence divergence occurs within Euplotes. A total of 14 new gene sequences, comprising four SSU rDNA and 10 CO1 (including three species for the first time) were obtained. Phylogenetic analyses were carried out based on sequences of two DNA fragments from the same 27 isolates. We found that CO1 revealed a larger interspecific divergence than the SSU rRNA gene, thus demonstrating a higher resolution for separating congeners. Genetic distances differ significantly at the species level. Euplotes balteatus was revealed to have a large intraspecific variation at two loci, while E. vannus showed different levels of haplotype variability, which appeared as a polyphyletic cluster on the CO1 tree. These high genetic divergences suggest the presence of more cryptic species. By contrast, the CO1 gene showed low variability within E. raikovi, appearing as monophyletic clusters, which indicates that this species could be identified based on this gene. Conclusively, CO1 is a suitable marker for the study of genetic diversity within Euplotes, and increased taxon sampling gives an opportunity to screen relationships among members of this genus. Additionally, current data present no clear biogeographical pattern for Euplotes.
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Affiliation(s)
- Congcong Wang
- Key Laboratory of Mariculture, Ministry of Education, College of Fisheries, Ocean University of China, Qingdao 266003, China;
| | - Yue Hu
- Oxford Sixth Form College, Oxford OX1 4HT, UK;
| | - Alan Warren
- Department of Life Sciences, Natural History Museum, London SW7 5BD, UK;
| | - Xiaozhong Hu
- Key Laboratory of Mariculture, Ministry of Education, College of Fisheries, Ocean University of China, Qingdao 266003, China;
- Correspondence: ; Tel.: +86-532-8203-1610
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Chromosome organization and gene expansion in the highly fragmented genome of the ciliate Strombidium stylifer. J Genet Genomics 2021; 48:908-916. [PMID: 34452852 DOI: 10.1016/j.jgg.2021.05.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 04/29/2021] [Accepted: 05/13/2021] [Indexed: 02/01/2023]
Abstract
Chromosomes are well-organized carriers of genetic information in eukaryotes and are usually quite long, carrying hundreds and thousands of genes. Intriguingly, a clade of single-celled ciliates, Spirotrichea, feature nanochromosomes-also called "gene-sized chromosomes". These chromosomes predominantly carry only one gene, flanked by short telomere sequences. However, the organization and copy number variation of the chromosomes in these highly fragmented genomes remain unexplored in many groups of Spirotrichea, including the marine Strombidium. Using deep genome sequencing, we assembled the macronuclear genome of Strombidium stylifer into more than 18,000 nanochromosomes (~2.4 Kb long on average). Our results show that S. stylifer occupies an intermediate position during the evolutionary history of Strombidium lineage and experienced significant expansions in several gene families related to guanyl ribonucleotide binding. Based on the nucleotide distribution bias analysis and conserved motifs search in non-genic regions, we found that the subtelomeric regions have a conserved adenine-thymine (AT)-rich sequence motif. We also found that the copy number of nanochromosomes lacks precise regulation. This work sheds light on the unique features of chromosome structure in eukaryotes with highly fragmented genomes and reveals that a rather specialized evolutionary strategy at the genomic level has resulted in great diversity within the ciliated lineages.
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Omar A, Moon JH, Jung JH. Molecular phylogeny of a new gonostomatid ciliate revealing a discrepancy between interphasic and cell divisional patterns (Ciliophora, Hypotricha). Eur J Protistol 2021; 79:125794. [PMID: 33975056 DOI: 10.1016/j.ejop.2021.125794] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Revised: 03/07/2021] [Accepted: 04/06/2021] [Indexed: 10/21/2022]
Abstract
The morphology, ontogenesis, and molecular phylogeny of a new ciliate, Gonostomum koreanum n. sp., discovered in a terrestrial moss sample from South Korea, were investigated. Morphologically, it is characterized by a gonostomatid oral apparatus, two macronuclear nodules, six frontoventral rows, the two rightmost of which (frontoventral rows V and VI) extend posteriorly to near pretransverse and transverse cirri, and three dorsal kineties each with a single caudal cirrus posteriorly. The new species is easily confused with members of the genus Metagonostomum because of the long frontoterminal cirral row but differs mainly in the de novo (vs. intrakinetal) origin of anlage VI, a character found only in Gonostomum and Paragonostomum. To solve the discrepancy between the interphasic and ontogenetic patterns, we additionally performed morphological and multigene analyses on three gonostomatid species, namely Gonostomum koreanum n. sp. and its morphologically (M. gonostomoida) and ontogenetically (G. kuehnelti) most similar species. The multigene analyses show that the new species is closely related to G. kuehnelti and the core gonostomatids consists of five groups based on the origin of the frontoventral rows.
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Affiliation(s)
- Atef Omar
- Natural Science Research Institute, Gangneung-Wonju National University, Gangneung 25457, South Korea; Department of Zoology, Al Azhar University, Assiut 71524, Egypt
| | - Ji Hye Moon
- Department of Biology, Gangneung-Wonju National University, Gangneung 25457, South Korea
| | - Jae-Ho Jung
- Department of Biology, Gangneung-Wonju National University, Gangneung 25457, South Korea.
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Jiang N, Xue DY, Han HX, Cheng R. Estimating hybridization as a consequence of climatic fluctuations: A case study of two geometridae species. Mol Phylogenet Evol 2021; 161:107168. [PMID: 33798671 DOI: 10.1016/j.ympev.2021.107168] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 02/05/2021] [Accepted: 03/26/2021] [Indexed: 10/21/2022]
Abstract
In some cases, the phylogenetic analysis based on the mitochondrial DNA (mtDNA) and the nuclear DNA (ncDNA) are discordant. There are three major causes of the discordance within insects, including hybridization, incomplete lineage sorting (ILS) and infection by Wolbachia. In this study, we used a combination of multilocus and coalescent analyses to explore these processes occurred during the evolutionary history of Limbatochlamys rosthorni Rothschild, 1894 and Limbatochlamys pararosthorni Han and Xue, 2005. The ncDNA phylogenetic tree supported two reciprocally monophyletic species, whereas the mtDNA results failed to reveal such a structure and revealed an extensive level of admixture between two species. Because of very low Wolbachia infection rates (<20%), we firstly excluded this reason for the discordance. The fixed nucleotide differences and large genetic distances (1.5-2.5%) at the ncDNA genes suggested that the lineage sorting process between these two species is nearly complete and two species have experienced a prolonged period of independent evolution. Thus, we secondly excluded ILS. Sharing haplotypes, mtDNA gene flow occurring and the transitional samples with morphological features supported hybridization. The distribution contraction during glaciations and postglacial distribution expansion might have facilitated hybridization. Taken together, our study indicates that the current genetic structure of L. rosthorni and L. pararosthorni is the results of contraction and fragmentation into separated refugia during glaciations, followed by postglacial expansion and admixture.
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Affiliation(s)
- Nan Jiang
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Da-Yong Xue
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Hong-Xiang Han
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.
| | - Rui Cheng
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.
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Fan X, Yao S, Luo X, Dong T, Xu Y, Chen L, Bourland W, Zhao Y, Huang J. Some morphologically distinguishable hypotrich ciliates share identical 18S rRNA gene sequences – taxonomic insights from a case study on Oxytricha species (Protista, Ciliophora). Zool J Linn Soc 2021. [DOI: 10.1093/zoolinnean/zlaa145] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
Modern taxonomic studies of ciliated protozoa require both morphological and molecular data. One dilemma is how to distinguish morphologically similar species with few nucleotide differences in the widely used marker, the 18S rRNA gene. In the present study, two Oxytricha species were morphologically documented using light and electron microscopy. The mitochondrial cytochrome c oxidase subunit I (COI) gene and a fragment of the rRNA gene covering the 18S-ITS1-5.8S-ITS2-28S rRNA gene regions were sequenced. Phylogenetic analyses of all available Oxytricha granulifera-related populations were performed to reveal the internal relationships of this group. We described a new species, Oxytricha atypica sp. nov., distinguished from its congeners by having seven postoral ventral cirri resulting from the additional fragmentation of anlage V during ontogenesis. Although their 18S rRNA genes differ by only one nucleotide, divergence of the COI gene is as high as 11.8% between O. atypica and the closely related species, O. granulifera. All but one of the COI nucleotide substitutions were synonymous. We documented the highly conserved nature of the 18S rRNA gene in the morphospecies of Oxytricha. Based on these findings, we speculate that O. granulifera contains cryptic species or morphospecies needing further characterization, and new insights for the taxonomy of hypotrich ciliates are also discussed.
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Affiliation(s)
- Xinpeng Fan
- School of Life Sciences, East China Normal University, Shanghai, China
| | - Shunli Yao
- School of Life Sciences, East China Normal University, Shanghai, China
| | - Xiaotian Luo
- Key Laboratory of Aquatic Biodiversity and Conservation of the Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Tianyao Dong
- School of Life Sciences, East China Normal University, Shanghai, China
| | - Yuan Xu
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, China
| | - Lingyun Chen
- College of Life Science, Northwest Normal University, Lanzhou, China
| | - William Bourland
- Department of Biological Sciences, Boise State University, Boise, ID, USA
| | - Yan Zhao
- College of Life Sciences, Capital Normal University, Beijing, China
| | - Jie Huang
- Key Laboratory of Aquatic Biodiversity and Conservation of the Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
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Serra V, Gammuto L, Nitla V, Castelli M, Lanzoni O, Sassera D, Bandi C, Sandeep BV, Verni F, Modeo L, Petroni G. Morphology, ultrastructure, genomics, and phylogeny of Euplotes vanleeuwenhoeki sp. nov. and its ultra-reduced endosymbiont "Candidatus Pinguicoccus supinus" sp. nov. Sci Rep 2020; 10:20311. [PMID: 33219271 PMCID: PMC7679464 DOI: 10.1038/s41598-020-76348-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 09/30/2020] [Indexed: 01/30/2023] Open
Abstract
Taxonomy is the science of defining and naming groups of biological organisms based on shared characteristics and, more recently, on evolutionary relationships. With the birth of novel genomics/bioinformatics techniques and the increasing interest in microbiome studies, a further advance of taxonomic discipline appears not only possible but highly desirable. The present work proposes a new approach to modern taxonomy, consisting in the inclusion of novel descriptors in the organism characterization: (1) the presence of associated microorganisms (e.g.: symbionts, microbiome), (2) the mitochondrial genome of the host, (3) the symbiont genome. This approach aims to provide a deeper comprehension of the evolutionary/ecological dimensions of organisms since their very first description. Particularly interesting, are those complexes formed by the host plus associated microorganisms, that in the present study we refer to as "holobionts". We illustrate this approach through the description of the ciliate Euplotes vanleeuwenhoeki sp. nov. and its bacterial endosymbiont "Candidatus Pinguicoccus supinus" gen. nov., sp. nov. The endosymbiont possesses an extremely reduced genome (~ 163 kbp); intriguingly, this suggests a high integration between host and symbiont.
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Affiliation(s)
- Valentina Serra
- Department of Biology, University of Pisa, Via Volta 4/6, 56126, Pisa, Italy
| | - Leandro Gammuto
- Department of Biology, University of Pisa, Via Volta 4/6, 56126, Pisa, Italy
| | - Venkatamahesh Nitla
- Department of Biology, University of Pisa, Via Volta 4/6, 56126, Pisa, Italy
| | - Michele Castelli
- Department of Biosciences, Romeo and Enrica Invernizzi Pediatric Research Center, University of Milan, Milan, Italy
- Department of Biology and Biotechnology "Lazzaro Spallanzani", Pavia University, Pavia, Italy
| | - Olivia Lanzoni
- Department of Biology, University of Pisa, Via Volta 4/6, 56126, Pisa, Italy
| | - Davide Sassera
- Department of Biology and Biotechnology "Lazzaro Spallanzani", Pavia University, Pavia, Italy
| | - Claudio Bandi
- Department of Biosciences, Romeo and Enrica Invernizzi Pediatric Research Center, University of Milan, Milan, Italy
| | | | - Franco Verni
- Department of Biology, University of Pisa, Via Volta 4/6, 56126, Pisa, Italy
| | - Letizia Modeo
- Department of Biology, University of Pisa, Via Volta 4/6, 56126, Pisa, Italy.
- CIME, Centro Interdipartimentale di Microscopia Elettronica, Università di Pisa, Pisa, Italy.
- CISUP, Centro per l'Integrazione della Strumentazione dell'Università di Pisa, Pisa, India.
| | - Giulio Petroni
- Department of Biology, University of Pisa, Via Volta 4/6, 56126, Pisa, Italy.
- CIME, Centro Interdipartimentale di Microscopia Elettronica, Università di Pisa, Pisa, Italy.
- CISUP, Centro per l'Integrazione della Strumentazione dell'Università di Pisa, Pisa, India.
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14
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Valbonesi A, Di Giuseppe G, Vallesi A, Luporini P. Two new species of Euplotes with cirrotype-9, Euplotes foissneri sp. nov. and Euplotes warreni sp. nov. (Ciliophora, Spirotrichea, Euplotida), from the coasts of Patagonia: implications from their distant, early and late branching in the Euplotes phylogenetic tree. Int J Syst Evol Microbiol 2020; 71. [PMID: 33201796 DOI: 10.1099/ijsem.0.004568] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Two new Euplotes species have been isolated from cold shallow sandy sediments of the extreme Southern Chilean coasts: Euplotes foissneri sp. nov., from a low-salinity site at Puerto Natales on the Pacific coast, and Euplotes warreni sp. nov., from a marine site at Punta Arenas on the Atlantic coast. Euplotes foissneri has a medium body size (53×36 µm in vivo), a dorsal surface marked by six prominent ridges, a double dargyrome, six dorsal and two ventrolateral kineties, a buccal field extending to about 3/4 of the body length, an adoral zone composed of 28-32 membranelles, and nine fronto-ventral, five transverse and two or three caudal cirri. The bulky, hook-, horseshoe- or 3-shaped macronucleus is associated with one sub-spherical micronucleus. The central body region hosts taxonomically unidentified endosymbiotic eubacteria. Euplotes warreni has a small body size (39×27 µm in vivo), a smooth dorsal surface marked by three deep grooves, a double dargyrome, four dorsal and two ventrolateral kineties, a buccal field extending to about 2/3 of the body length, an adoral zone composed of 23-25 adoral membranelles, and nine fronto-ventral, five transverse and three caudal cirri. The macronucleus is hook- or C-shaped and associated with one spherical micronucleus. Endosymbiotic bacteria belonging to the genus Francisella reside preferentially in the anterior cell region. Both species lack the fronto-ventral cirrus numbered 'V/2', whereby their cirrotype-9 conforms to the so-called 'pattern I', which is the basic distinctive trait of the genus Euplotopsis Borror and Hill, 1995. Phylogenetic analyses of small subunit rRNA gene sequences, however, classify E. warreni into its own early branching clade and E. foissneri into a late branching clade. This indicates a polyphyletic nature and taxonomic inconsistency of the genus Euplotopsis, which was erected to include Euplotes species with cirrotype-9 pattern I.
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Affiliation(s)
- Alessandro Valbonesi
- Laboratory of Eukaryotic Microbiology and Animal Biology, School of Bioscience and Veterinary Medicine, University of Camerino, Italy
| | | | - Adriana Vallesi
- Laboratory of Eukaryotic Microbiology and Animal Biology, School of Bioscience and Veterinary Medicine, University of Camerino, Italy
| | - Pierangelo Luporini
- Laboratory of Eukaryotic Microbiology and Animal Biology, School of Bioscience and Veterinary Medicine, University of Camerino, Italy
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15
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Xu J, Wilkinson M, Chen M, Zhang Q, Yang R, Yi Z. Concatenated data and dense taxon sampling clarify phylogeny and ecological transitions within Hypotricha. ZOOL SCR 2020. [DOI: 10.1111/zsc.12459] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jiahui Xu
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture School of Life Sciences South China Normal University Guangzhou China
| | - Mark Wilkinson
- Department of Life Sciences Natural History Museum London UK
| | - Miaoying Chen
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture School of Life Sciences South China Normal University Guangzhou China
| | - Qi Zhang
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture School of Life Sciences South China Normal University Guangzhou China
| | - Ran Yang
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture School of Life Sciences South China Normal University Guangzhou China
| | - Zhenzhen Yi
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture School of Life Sciences South China Normal University Guangzhou China
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16
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Zhu C, Bass D, Wang Y, Shen Z, Song W, Yi Z. Environmental Parameters and Substrate Type Drive Microeukaryotic Community Structure During Short-Term Experimental Colonization in Subtropical Eutrophic Freshwaters. Front Microbiol 2020; 11:555795. [PMID: 33072015 PMCID: PMC7541896 DOI: 10.3389/fmicb.2020.555795] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Accepted: 08/24/2020] [Indexed: 12/12/2022] Open
Abstract
Microeukaryotes are key components of aquatic ecosystems and play crucial roles in aquatic food webs. However, influencing factors and potential assembly mechanisms for microeukaryotic community on biofilms are rarely studied. Here, those of microeukaryotic biofilms in subtropical eutrophic freshwaters were investigated for the first time based on 2,585 operational taxonomic units (OTUs) from 41 samples, across different environmental conditions and substrate types. Following conclusions were drawn: (1) Environmental parameters were more important than substrate types in structuring microeukaryotic community of biofilms in subtropical eutrophic freshwaters. (2) In the fluctuating river, there was a higher diversity of OTUs and less predictability of community composition than in the stable lake. Sessile species were more likely to be enriched on smooth surfaces of glass slides, while both free-swimming and attached organisms occurred within holes inside PFUs (polyurethane foam units). (3) Both species sorting and neutral process were mechanisms for assembly of microeukaryotic biofilms, but their importance varied depending on different habitats and substrates. (4) The effect of species sorting was slightly higher than the neutral process in river biofilms due to stronger environmental filtering. Species sorting was a stronger force structuring communities on glass slides than PFUs with more niche availability. Our study sheds light on assembly mechanisms for microeukaryotic community on different habitat and substrate types, showing that the resulting communities are determined by both sets of variables, in this case primarily habitat type. The balance of neutral process and species sorting differed between habitats, but the high alpha diversity of microeukaryotes in both led to similar sets of lifecycle traits being selected for in each case.
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Affiliation(s)
- Changyu Zhu
- Institute of Evolution and Marine Biodiversity, College of Fisheries, Ocean University of China, Qingdao, China.,Pilot National Laboratory for Marine Science and Technology, Qingdao, China.,Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, School of Life Sciences, South China Normal University, Guangzhou, China
| | - David Bass
- Department of Life Sciences, Natural History Museum, London, United Kingdom
| | - Yutao Wang
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, School of Life Sciences, South China Normal University, Guangzhou, China.,Dongli Planting and Farming Industrial Co., Ltd., Lianzhou, China
| | - Zhuo Shen
- Institute of Microbial Ecology and Matter Cycle, School of Marine Sciences, Sun Yat-sen University, Zhuhai, China.,Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China
| | - Weibo Song
- Institute of Evolution and Marine Biodiversity, College of Fisheries, Ocean University of China, Qingdao, China.,Pilot National Laboratory for Marine Science and Technology, Qingdao, China
| | - Zhenzhen Yi
- Pilot National Laboratory for Marine Science and Technology, Qingdao, China.,Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, School of Life Sciences, South China Normal University, Guangzhou, China
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17
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Jin D, Qu Z, Wei B, Montagnes DJS, Fan X, Chen X. Two parasitic ciliates (Protozoa: Ciliophora: Phyllopharyngea) isolated from respiratory-mucus of an unhealthy beluga whale: characterization, phylogeny and an assessment of morphological adaptations. Zool J Linn Soc 2020. [DOI: 10.1093/zoolinnean/zlaa086] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Abstract
Ciliates occur in the blowholes of marine mammals, but our understanding of their biology is poor. Consequently, we investigated an infestation of ciliates in an unhealthy, captive beluga whale that was exhibiting accelerated breathing, leukocytosis and expulsion of unusually large amounts of viscous sputum. This sputum contained ~104 ciliates mL-1 (when healthy, numbers were ten- to 100-fold lower). One known ciliate species, Planilamina ovata, is fully characterized, and a new species, Kyaroikeus paracetarius sp. nov., is here described. The new species is established based on its larger number of left kineties over its only congener. Sequences of small-subunit rDNA, large-subunit rDNA and ITS1-5.8S-ITS2 regions of these two taxa were used in phylogenetic analyses, inferring that Kyaroikeus and Planilamina have close affinity with the free-living family Dysteriidae, contradicting their morphology-based assignment to the family Kyaroikeidae. We suggest that Kyaroikeidae be relegated to subfamily status. Finally, by comparing parasitic species with free-living taxa, we suggest how these ciliates have adapted to their unique environment and how they may have initially invaded the host. We provide essential data and concepts for the continued evaluation of ciliate-parasites in whale blowholes.
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Affiliation(s)
- Didi Jin
- School of Marine Sciences, Ningbo University, Ningbo, China
| | - Zhishuai Qu
- Department of Ecology, University of Kaiserslautern, Kaiserslautern, Germany
| | - Bojue Wei
- School of Marine Sciences, Ningbo University, Ningbo, China
| | | | - Xinpeng Fan
- School of Life Sciences, East China Normal University, Shanghai, China
| | - Xiangrui Chen
- School of Marine Sciences, Ningbo University, Ningbo, China
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18
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Zhang Q, Xu J, Warren A, Yang R, Shen Z, Yi Z. Assessing the utility of Hsp90 gene for inferring evolutionary relationships within the ciliate subclass Hypotricha (Protista, Ciliophora). BMC Evol Biol 2020; 20:86. [PMID: 32677880 PMCID: PMC7364784 DOI: 10.1186/s12862-020-01653-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 07/07/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Although phylogenomic analyses are increasingly used to reveal evolutionary relationships among ciliates, relatively few nuclear protein-coding gene markers have been tested for their suitability as candidates for inferring phylogenies within this group. In this study, we investigate the utility of the heat-shock protein 90 gene (Hsp90) as a marker for inferring phylogenetic relationships among hypotrich ciliates. RESULTS A total of 87 novel Hsp90 gene sequences of 10 hypotrich species were generated. Of these, 85 were distinct sequences. Phylogenetic analyses based on these data showed that: (1) the Hsp90 gene amino acid trees are comparable to the small subunit rDNA tree for recovering phylogenetic relationships at the rank of class, but lack sufficient phylogenetic signal for inferring evolutionary relationships at the genus level; (2) Hsp90 gene paralogs are recent and therefore unlikely to pose a significant problem for recovering hypotrich clades; (3) definitions of some hypotrich orders and families need to be revised as their monophylies are not supported by various gene markers; (4) The order Sporadotrichida is paraphyletic, but the monophyly of the "core" Urostylida is supported; (5) both the subfamily Oxytrichinae and the genus Urosoma seem to be non-monophyletic, but monophyly of Urosoma is not rejected by AU tests. CONCLUSIONS Our results for the first time demonstrate that the Hsp90 gene is comparable to SSU rDNA for recovering phylogenetic relationships at the rank of class, and its paralogs are unlikely to pose a significant problem for recovering hypotrich clades. This study shows the value of careful gene marker selection for phylogenomic analyses of ciliates.
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Affiliation(s)
- Qi Zhang
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, School of Life Science, South China Normal University, Guangzhou, 510631, China.,Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, 266237, China
| | - Jiahui Xu
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, School of Life Science, South China Normal University, Guangzhou, 510631, China.,Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, 266237, China
| | - Alan Warren
- Department of Life Sciences, Natural History Museum, London, SW7 5BD, UK
| | - Ran Yang
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, School of Life Science, South China Normal University, Guangzhou, 510631, China
| | - Zhuo Shen
- Institute of Microbial Ecology and Matter Cycle, School of Marine Sciences, Sun Yat-sen University, Zhuhai, 519000, China. .,Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, 519000, China.
| | - Zhenzhen Yi
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, School of Life Science, South China Normal University, Guangzhou, 510631, China. .,Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, 266237, China.
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19
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Li Y, Chen X, Wu K, Pan J, Long H, Yan Y. Characterization of Simple Sequence Repeats (SSRs) in Ciliated Protists Inferred by Comparative Genomics. Microorganisms 2020; 8:microorganisms8050662. [PMID: 32370063 PMCID: PMC7285179 DOI: 10.3390/microorganisms8050662] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 04/24/2020] [Accepted: 04/26/2020] [Indexed: 01/02/2023] Open
Abstract
Simple sequence repeats (SSRs) are prevalent in the genomes of all organisms. They are widely used as genetic markers, and are insertion/deletion mutation hotspots, which directly influence genome evolution. However, little is known about such important genomic components in ciliated protists, a large group of unicellular eukaryotes with extremely long evolutionary history and genome diversity. With recent publications of multiple ciliate genomes, we start to get a chance to explore perfect SSRs with motif size 1-100 bp and at least three motif repeats in nine species of two ciliate classes, Oligohymenophorea and Spirotrichea. We found that homopolymers are the most prevalent SSRs in these A/T-rich species, with AAA (lysine, charged amino acid; also seen as an SSR with one-adenine motif repeated three times) being the codons repeated at the highest frequencies in coding SSR regions, consistent with the widespread alveolin proteins rich in lysine repeats as found in Tetrahymena. Micronuclear SSRs are universally more abundant than the macronuclear ones of the same motif-size, except for the 8-bp-motif SSRs in extensively fragmented chromosomes. Both the abundance and A/T content of SSRs decrease as motif-size increases, while the abundance is positively correlated with the A/T content of the genome. Also, smaller genomes have lower proportions of coding SSRs out of all SSRs in Paramecium species. This genome-wide and cross-species analysis reveals the high diversity of SSRs and reflects the rapid evolution of these simple repetitive elements in ciliate genomes.
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20
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Wang Y, Jiang Y, Liu Y, Li Y, Katz LA, Gao F, Yan Y. Comparative Studies on the Polymorphism and Copy Number Variation of mtSSU rDNA in Ciliates (Protista, Ciliophora): Implications for Phylogenetic, Environmental, and Ecological Research. Microorganisms 2020; 8:microorganisms8030316. [PMID: 32106521 PMCID: PMC7142639 DOI: 10.3390/microorganisms8030316] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 02/20/2020] [Accepted: 02/21/2020] [Indexed: 01/21/2023] Open
Abstract
While nuclear small subunit ribosomal DNA (nSSU rDNA) is the most commonly-used gene marker in studying phylogeny, ecology, abundance, and biodiversity of microbial eukaryotes, mitochondrial small subunit ribosomal DNA (mtSSU rDNA) provides an alternative. Recently, both copy number variation and sequence variation of nSSU rDNA have been demonstrated for diverse organisms, which can contribute to misinterpretation of microbiome data. Given this, we explore patterns for mtSSU rDNA among 13 selected ciliates (representing five classes), a major component of microbial eukaryotes, estimating copy number and sequence variation and comparing to that of nSSU rDNA. Our study reveals: (1) mtSSU rDNA copy number variation is substantially lower than that for nSSU rDNA; (2) mtSSU rDNA copy number ranges from 1.0 × 104 to 8.1 × 105; (3) a most common sequence of mtSSU rDNA is also found in each cell; (4) the sequence variation of mtSSU rDNA are mainly indels in poly A/T regions, and only half of species have sequence variation, which is fewer than that for nSSU rDNA; and (5) the polymorphisms between haplotypes of mtSSU rDNA would not influence the phylogenetic topology. Together, these data provide more insights into mtSSU rDNA as a powerful marker especially for microbial ecology studies.
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Affiliation(s)
- Yurui Wang
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China; (Y.W.); (Y.J.); (Y.L.); (Y.L.); (F.G.)
- Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao 266003, China
| | - Yaohan Jiang
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China; (Y.W.); (Y.J.); (Y.L.); (Y.L.); (F.G.)
- Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao 266003, China
| | - Yongqiang Liu
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China; (Y.W.); (Y.J.); (Y.L.); (Y.L.); (F.G.)
- Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao 266003, China
| | - Yuan Li
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China; (Y.W.); (Y.J.); (Y.L.); (Y.L.); (F.G.)
- Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao 266003, China
| | - Laura A. Katz
- Department of Biological Sciences, Smith College, Northampton, MA 01063, USA;
| | - Feng Gao
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China; (Y.W.); (Y.J.); (Y.L.); (Y.L.); (F.G.)
- Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao 266003, China
| | - Ying Yan
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China; (Y.W.); (Y.J.); (Y.L.); (Y.L.); (F.G.)
- Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao 266003, China
- Department of Biological Sciences, Smith College, Northampton, MA 01063, USA;
- Correspondence:
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21
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Comparative Transcriptome Analyses during the Vegetative Cell Cycle in the Mono-Cellular Organism Pseudokeronopsis erythrina (Alveolata, Ciliophora). Microorganisms 2020; 8:microorganisms8010108. [PMID: 31940957 PMCID: PMC7022673 DOI: 10.3390/microorganisms8010108] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 01/08/2020] [Accepted: 01/09/2020] [Indexed: 01/18/2023] Open
Abstract
Studies focusing on molecular mechanisms of cell cycles have been lagging in unicellular eukaryotes compared to other groups. Ciliates, a group of unicellular eukaryotes, have complex cell division cycles characterized by multiple events. During their vegetative cell cycle, ciliates undergo macronuclear amitosis, micronuclear mitosis, stomatogenesis and somatic cortex morphogenesis, and cytokinesis. Herein, we used the hypotrich ciliate Pseudokeronopsis erythrina, whose morphogenesis has been well studied, to examine molecular mechanisms of ciliate vegetative cell cycles. Single-cell transcriptomes of the growth (G) and cell division (D) stages were compared. The results showed that (i) More than 2051 significantly differentially expressed genes (DEGs) were detected, among which 1545 were up-regulated, while 256 were down-regulated at the D stage. Of these, 11 randomly picked DEGs were validated by reverse transcription quantitative polymerase chain reaction (RT-qPCR); (ii) Enriched DEGs during the D stage of the vegetative cell cycle of P. erythrina were involved in development, cortex modifications, and several organelle-related biological processes, showing correspondence of molecular evidence to morphogenetic changes for the first time; (iii) Several individual components of molecular mechanisms of ciliate vegetative division, the sexual cell cycle and cellular regeneration overlap; and (iv) The P. erythrina cell cycle and division have the same essential components as other eukaryotes, including cyclin-dependent kinases (CDKs), cyclins, and genes closely related to cell proliferation, indicating the conserved nature of this biological process. Further studies are needed focusing on detailed inventory and gene interactions that regulate specific ciliated cell-phase events.
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22
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Liu W, Zhang K, Chen C, Li J, Tan Y, Warren A, Lin X, Song W. Overview of the biodiversity and geographic distribution of aloricate oligotrich ciliates (Protozoa, Ciliophora, Spirotrichea) in coastal waters of southern China. SYST BIODIVERS 2019. [DOI: 10.1080/14772000.2019.1691081] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Weiwei Liu
- Laboratory of Protozoology, Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, South China Normal University, Guangzhou 510631, China
- Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Science, Guangzhou 510301, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China
| | - Kexin Zhang
- Laboratory of Protozoology, Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, South China Normal University, Guangzhou 510631, China
| | - Changzhi Chen
- Laboratory of Protozoology, Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, South China Normal University, Guangzhou 510631, China
| | - Jiqiu Li
- Laboratory of Protozoology, Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, South China Normal University, Guangzhou 510631, China
| | - Yehui Tan
- Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Science, Guangzhou 510301, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China
| | - Alan Warren
- Department of Life Sciences, Natural History Museum, Cromwell Road, London SW75BD, UK
| | - Xiaofeng Lin
- Laboratory of Protozoology, Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, South China Normal University, Guangzhou 510631, China
| | - Weibo Song
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao 266003, China
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23
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Shazib SUA, Vďačný P, Slovák M, Gentekaki E, Shin MK. Deciphering phylogenetic relationships and delimiting species boundaries using a Bayesian coalescent approach in protists: A case study of the ciliate genus Spirostomum (Ciliophora, Heterotrichea). Sci Rep 2019; 9:16360. [PMID: 31704993 PMCID: PMC6841689 DOI: 10.1038/s41598-019-52722-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 10/22/2019] [Indexed: 11/09/2022] Open
Abstract
The ciliate genus Spirostomum comprises eight morphospecies, inhabiting diverse aquatic environments worldwide, where they can be used as water quality indicators. Although Spirostomum species are relatively easily identified using morphological methods, the previous nuclear rDNA-based phylogenies indicated several conflicts in morphospecies delineation. Moreover, the single locus phylogenies and previous analytical approaches could not unambiguously resolve phylogenetic relationships among Spirostomum morphospecies. Here, we attempt to investigate species boundaries and evolutionary history of Spirostomum taxa, using 166 new sequences from multiple populations employing one mitochondrial locus (CO1 gene) and two nuclear loci (rRNA operon and alpha-tubulin gene). In accordance with previous studies, relationships among the eight Spirostomum morphospecies were poorly supported statistically in individual gene trees. To overcome this problem, we utilised for the first time in ciliates the Bayesian coalescent approach, which accounts for ancestral polymorphisms, incomplete lineage sorting, and recombination. This strategy enabled us to robustly resolve deep relationships between Spirostomum species and to support the hypothesis that taxa with compact macronucleus and taxa with moniliform macronucleus each form a distinct lineage. Bayesian coalescent-based delimitation analyses strongly statistically supported the traditional morphospecies concept but also indicated that there are two S. minus-like cryptic species and S. teres is non-monophyletic. Spirostomum teres was very likely defined by a set of ancestral features of lineages that also gave rise to S. yagiui and S. dharwarensis. However, molecular data from type populations of the morphospecies S. minus and S. teres are required to unambiguously resolve the taxonomic problems.
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Affiliation(s)
| | - Peter Vďačný
- Department of Zoology, Comenius University in Bratislava, 842 15, Bratislava, Slovakia
| | - Marek Slovák
- Plant Science and Biodiversity Centre, Institute of Botany, Slovak Academy of Sciences, 845 23, Bratislava, Slovakia.,Department of Botany, Charles University, 128 01, Prague, Czech Republic
| | - Eleni Gentekaki
- School of Science, Mae Fah Luang University, Chiang Rai, 57100, Thailand
| | - Mann Kyoon Shin
- Department of Biological Science, University of Ulsan, Ulsan, 44610, South Korea.
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24
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Zhan Z, Li J, Xu K. Ciliate Environmental Diversity Can Be Underestimated by the V4 Region of SSU rDNA: Insights from Species Delimitation and Multilocus Phylogeny of Pseudokeronopsis (Protist, Ciliophora). Microorganisms 2019; 7:microorganisms7110493. [PMID: 31717798 PMCID: PMC6920991 DOI: 10.3390/microorganisms7110493] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2019] [Revised: 10/22/2019] [Accepted: 10/25/2019] [Indexed: 12/03/2022] Open
Abstract
Metabarcoding and high-throughput sequencing methods have greatly improved our understanding of protist diversity. Although the V4 region of small subunit ribosomal DNA (SSU-V4 rDNA) is the most widely used marker in DNA metabarcoding of eukaryotic microorganisms, doubts have recently been raised about its suitability. Here, using the widely distributed ciliate genus Pseudokeronopsis as an example, we assessed the potential of SSU-V4 rDNA and four other nuclear and mitochondrial markers for species delimitation and phylogenetic reconstruction. Our studies revealed that SSU-V4 rDNA is too conservative to distinguish species, and a threshold of 97% and 99% sequence similarity detected only one and three OTUs, respectively, from seven species. On the basis of the comparative analysis of the present and previously published data, we proposed the multilocus marker including the nuclear 5.8S rDNA combining the internal transcribed spacer regions (ITS1-5.8S-ITS2) and the hypervariable D2 region of large subunit rDNA (LSU-D2) as an ideal barcode rather than the mitochondrial cytochrome c oxidase subunit 1 gene, and the ITS1-5.8S-ITS2 as a candidate metabarcoding marker for ciliates. Furthermore, the compensating base change and tree-based criteria of ITS2 and LSU-D2 were useful in complementing the DNA barcoding and metabarcoding methods by giving second structure and phylogenetic evidence.
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Affiliation(s)
- Zifeng Zhan
- Laboratory of Marine Organism Taxonomy and Phylogeny, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (Z.Z.); (J.L.)
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266071, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Ju Li
- Laboratory of Marine Organism Taxonomy and Phylogeny, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (Z.Z.); (J.L.)
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Kuidong Xu
- Laboratory of Marine Organism Taxonomy and Phylogeny, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (Z.Z.); (J.L.)
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266071, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Correspondence:
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25
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Wang C, Yan Y, Chen X, Al‐Farraj SA, El‐Serehy HA, Gao F. Further analyses on the evolutionary “key‐protist”
Halteria
(Protista, Ciliophora) based on transcriptomic data. ZOOL SCR 2019. [DOI: 10.1111/zsc.12380] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Chundi Wang
- Institute of Evolution & Marine Biodiversity Ocean University of China Qingdao China
- Key Laboratory of Mariculture (Ocean University of China) Ministry of Education Qingdao China
| | - Ying Yan
- Institute of Evolution & Marine Biodiversity Ocean University of China Qingdao China
- Key Laboratory of Mariculture (Ocean University of China) Ministry of Education Qingdao China
| | - Xiao Chen
- Institute of Evolution & Marine Biodiversity Ocean University of China Qingdao China
- Key Laboratory of Mariculture (Ocean University of China) Ministry of Education Qingdao China
- Department of Genetics and Development Columbia University Medical Center New York NY USA
| | - Saleh A. Al‐Farraj
- Zoology Department, College of Science King Saud University Riyadh Saudi Arabia
| | - Hamed A. El‐Serehy
- Zoology Department, College of Science King Saud University Riyadh Saudi Arabia
| | - Feng Gao
- Institute of Evolution & Marine Biodiversity Ocean University of China Qingdao China
- Key Laboratory of Mariculture (Ocean University of China) Ministry of Education Qingdao China
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26
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Zhang T, Fan X, Gao F, Al-Farraj SA, El-Serehy HA, Song W. Further analyses on the phylogeny of the subclass Scuticociliatia (Protozoa, Ciliophora) based on both nuclear and mitochondrial data. Mol Phylogenet Evol 2019; 139:106565. [PMID: 31326515 DOI: 10.1016/j.ympev.2019.106565] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 07/13/2019] [Accepted: 07/17/2019] [Indexed: 11/24/2022]
Abstract
So far, the phylogenetic studies on ciliated protists have mainly based on single locus, the nuclear ribosomal DNA (rDNA). In order to avoid the limitations of single gene/genome trees and to add more data to systematic analyses, information from mitochondrial DNA sequence has been increasingly used in different lineages of ciliates. The systematic relationships in the subclass Scuticociliatia are extremely confused and largely unresolved based on nuclear genes. In the present study, we have characterized 72 new sequences, including 40 mitochondrial cytochrome oxidase c subunit I (COI) sequences, 29 mitochondrial small subunit ribosomal DNA (mtSSU-rDNA) sequences and three nuclear small subunit ribosomal DNA (nSSU-rDNA) sequences from 47 isolates of 44 morphospecies. Phylogenetic analyses based on single gene as well as concatenated data were performed and revealed: (1) compared to mtSSU-rDNA, COI gene reveals more consistent relationships with those of nSSU-rDNA; (2) the secondary structures of mtSSU-rRNA V4 region are predicted and compared in scuticociliates, which can contribute to discrimination of closely related species; (3) neither nuclear nor mitochondrial data support the monophyly of the order Loxocephalida, which may represent some divergent and intermediate lineages between the subclass Scuticociliatia and Hymenostomatia; (4) the assignments of thigmotrichids to the order Pleuronematida and the confused taxon Sulcigera comosa to the genus Histiobalantium are confirmed by mitochondrial genes; (5) both nuclear and mitochondrial data reveal that the species in the family Peniculistomatidae always group in the genus Pleuronema, suggesting that peniculistomatids are more likely evolved from Pleuronema-like ancestors; (6) mitochondrial genes support the monophyly of the order Philasterida, but the relationships among families of the order Philasterida remain controversial due to the discrepancies between their morphological and molecular data.
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Affiliation(s)
- Tengteng Zhang
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China; Key Laboratory of Mariculture (Ocean University of China), Ministry of Education, Qingdao 266003, China
| | - Xinpeng Fan
- School of Life Sciences, East China Normal University, Shanghai 200241 China
| | - Feng Gao
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China; Key Laboratory of Mariculture (Ocean University of China), Ministry of Education, Qingdao 266003, China.
| | - Saleh A Al-Farraj
- Zoology Department, College of Science, King Saud University, Riyadh 11451, Saudi Arabia
| | - Hamed A El-Serehy
- Zoology Department, College of Science, King Saud University, Riyadh 11451, Saudi Arabia
| | - Weibo Song
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China; Key Laboratory of Mariculture (Ocean University of China), Ministry of Education, Qingdao 266003, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266003, China.
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27
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Spatio-temporal patterns of zooplankton in a main-stem dam affected tributary: a case study in the Xiangxi River of the Three Gorges Reservoir, China. SCIENCE CHINA-LIFE SCIENCES 2019; 62:1058-1069. [PMID: 31290096 DOI: 10.1007/s11427-018-9523-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 03/26/2019] [Indexed: 10/26/2022]
Abstract
As the ecologically important recipient channels for riverine ecosystems, tributaries provide unique microhabitats for microorganisms, among which zooplankton constitutes the most important heterotrophic organisms. In particular, the reduced water velocity caused by dams is more favorable for zooplankton development; therefore, dammed rivers are expected to support extremely diverse and abundant zooplankton communities and notably different spatiotemporal distribution patterns. So far, however, only very few molecular studies support these assumptions. Using high-throughput sequencing, a high number of 350 operational taxonomic units (OTUs; 97% cutoff) were retrieved from 30 samples collected in the Xiangxi River, the nearest large tributary upstream of the Three Gorges Dam. Zooplankton did not show significant spatial distribution in the channel. Instead, the community structures varied significantly over sampling dates, corroborating the seasonal patterns found in lakes and ponds in the subtropical zone. As expected, the community compositions were deterministically governed by environmental filtering processes (phylogenetic clustering), in which water velocity appeared to be much less important than other investigated environmental factors. Moreover, most of the detected phylotypes (OTUs) had a relatively high (>90%) sequence similarity to previously deposited sequences, suggesting a mediocre degree of genetic novelty within the zooplankton communities in the Xiangxi River.
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28
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Chen X, Jiang Y, Gao F, Zheng W, Krock TJ, Stover NA, Lu C, Katz LA, Song W. Genome analyses of the new model protist Euplotes vannus focusing on genome rearrangement and resistance to environmental stressors. Mol Ecol Resour 2019; 19:1292-1308. [PMID: 30985983 DOI: 10.1111/1755-0998.13023] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 04/05/2019] [Accepted: 04/08/2019] [Indexed: 12/11/2022]
Abstract
As a model organism for studies of cell and environmental biology, the free-living and cosmopolitan ciliate Euplotes vannus shows intriguing features like dual genome architecture (i.e., separate germline and somatic nuclei in each cell/organism), "gene-sized" chromosomes, stop codon reassignment, programmed ribosomal frameshifting (PRF) and strong resistance to environmental stressors. However, the molecular mechanisms that account for these remarkable traits remain largely unknown. Here we report a combined analysis of de novo assembled high-quality macronuclear (MAC; i.e., somatic) and partial micronuclear (MIC; i.e., germline) genome sequences for E. vannus, and transcriptome profiling data under varying conditions. The results demonstrate that: (a) the MAC genome contains more than 25,000 complete "gene-sized" nanochromosomes (~85 Mb haploid genome size) with the N50 ~2.7 kb; (b) although there is a high frequency of frameshifting at stop codons UAA and UAG, we did not observe impaired transcript abundance as a result of PRF in this species as has been reported for other euplotids; (c) the sequence motif 5'-TA-3' is conserved at nearly all internally-eliminated sequence (IES) boundaries in the MIC genome, and chromosome breakage sites (CBSs) are duplicated and retained in the MAC genome; (d) by profiling the weighted correlation network of genes in the MAC under different environmental stressors, including nutrient scarcity, extreme temperature, salinity and the presence of ammonia, we identified gene clusters that respond to these external physical or chemical stimulations, and (e) we observed a dramatic increase in HSP70 gene transcription under salinity and chemical stresses but surprisingly, not under temperature changes; we link this temperature-resistance to the evolved loss of temperature stress-sensitive elements in regulatory regions. Together with the genome resources generated in this study, which are available online at Euplotes vannus Genome Database (http://evan.ciliate.org), these data provide molecular evidence for understanding the unique biology of highly adaptable microorganisms.
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Affiliation(s)
- Xiao Chen
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China.,Department of Genetics and Development, Columbia University Medical Center, New York, New York
| | - Yaohan Jiang
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Feng Gao
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China.,Key Laboratory of Mariculture (Ministry of Education), Ocean University of China, Qingdao, China
| | - Weibo Zheng
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Timothy J Krock
- Department of Computer Science and Information Systems, Bradley University, Peoria, Illinois
| | - Naomi A Stover
- Department of Biology, Bradley University, Peoria, Illinois
| | - Chao Lu
- Department of Genetics and Development, Columbia University Medical Center, New York, New York
| | - Laura A Katz
- Department of Biological Sciences, Smith College, Northampton, Massachusetts
| | - Weibo Song
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
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29
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Liu Y, Nan B, Duan L, Cheng T, Bourland WA, Liu M, Zhao Y. A Simple and Rapid Cryopreservation Technique for Ciliates: A Long‐Term Storage Procedure Used for Marine Scuticociliates. J Eukaryot Microbiol 2019; 66:836-848. [DOI: 10.1111/jeu.12730] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Revised: 02/22/2019] [Accepted: 03/15/2019] [Indexed: 12/25/2022]
Affiliation(s)
- Yongqiang Liu
- Institute of Evolution & Marine Biodiversity Ocean University of China Qingdao 266003 China
- Laboratory for Marine Biology and Biotechnology Qingdao National Laboratory for Marine Science and Technology Qingdao 266003 China
| | - Bei Nan
- Institute of Evolution & Marine Biodiversity Ocean University of China Qingdao 266003 China
- Laboratory for Marine Biology and Biotechnology Qingdao National Laboratory for Marine Science and Technology Qingdao 266003 China
| | - Lili Duan
- Institute of Evolution & Marine Biodiversity Ocean University of China Qingdao 266003 China
- Laboratory for Marine Biology and Biotechnology Qingdao National Laboratory for Marine Science and Technology Qingdao 266003 China
| | - Ting Cheng
- Institute of Evolution & Marine Biodiversity Ocean University of China Qingdao 266003 China
- Laboratory for Marine Biology and Biotechnology Qingdao National Laboratory for Marine Science and Technology Qingdao 266003 China
| | - William A. Bourland
- Department of Biological Sciences Boise State University Boise Idaho 83725‐1515 USA
| | - Mingjian Liu
- Institute of Evolution & Marine Biodiversity Ocean University of China Qingdao 266003 China
| | - Yan Zhao
- Research Centre for Eco‐Environmental Sciences Chinese Academy of Sciences Beijing 100085 China
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30
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Wang Y, Wang C, Jiang Y, Katz LA, Gao F, Yan Y. Further analyses of variation of ribosome DNA copy number and polymorphism in ciliates provide insights relevant to studies of both molecular ecology and phylogeny. SCIENCE CHINA-LIFE SCIENCES 2019; 62:203-214. [PMID: 30671886 DOI: 10.1007/s11427-018-9422-5] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 09/08/2018] [Accepted: 11/06/2018] [Indexed: 11/26/2022]
Abstract
Sequence-based approaches, such as analyses of ribosome DNA (rDNA) clone libraries and high-throughput amplicon sequencing, have been used extensively to infer evolutionary relationships and elucidate the biodiversity in microbial communities. However, recent studies demonstrate both rDNA copy number variation and intra-individual (intra-genomic) sequence variation in many organisms, which challenges the application of the rDNA-based surveys. In ciliates, an ecologically important clade of microbial eukaryotes, rDNA copy number and sequence variation are rarely studied. In the present study, we estimate the intraindividual small subunit rDNA (SSU rDNA) copy number and sequence variation in a wide range of taxa covering nine classes and 18 orders of the phylum Ciliophora. Our studies reveal that: (i) intra-individual sequence variation of SSU rDNA is ubiquitous in all groups of ciliates detected and the polymorphic level varies among taxa; (ii) there is a most common version of SSU rDNA sequence in each cell that is highly predominant and may represent the germline micronuclear template; (iii) compared with the most common version, other variant sequences differ in only 1-3 nucleotides, likely generated during macronuclear (somatic) amplification; (iv) the intra-cell sequence variation is unlikely to impact phylogenetic analyses; (v) the rDNA copy number in ciliates is highly variable, ranging from 103 to 106, with the highest record in Stentor roeselii. Overall, these analyses indicate the need for careful consideration of SSU rDNA variation in analyses of the role of ciliates in ecosystems.
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Affiliation(s)
- Yurui Wang
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003, China
- Key Laboratory of Mariculture, Ocean University of China, Ministry of Education, Qingdao, 266003, China
| | - Chundi Wang
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003, China
- Key Laboratory of Mariculture, Ocean University of China, Ministry of Education, Qingdao, 266003, China
| | - Yaohan Jiang
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003, China
- Key Laboratory of Mariculture, Ocean University of China, Ministry of Education, Qingdao, 266003, China
| | - Laura A Katz
- Department of Biological Sciences, Smith College, Northampton, MA, 01063, USA
| | - Feng Gao
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003, China.
- Key Laboratory of Mariculture, Ocean University of China, Ministry of Education, Qingdao, 266003, China.
| | - Ying Yan
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003, China.
- Key Laboratory of Mariculture, Ocean University of China, Ministry of Education, Qingdao, 266003, China.
- Department of Biological Sciences, Smith College, Northampton, MA, 01063, USA.
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31
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Jiang Y, Zhang T, Vallesi A, Yang X, Gao F. Time-course analysis of nuclear events during conjugation in the marine ciliate Euplotes vannus and comparison with other ciliates (Protozoa, Ciliophora). Cell Cycle 2019; 18:288-298. [PMID: 30563432 DOI: 10.1080/15384101.2018.1558871] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Ciliates represent a morphologically and genetically distinct group of single-celled eukaryotes that segregate germline and somatic functions into two types of nuclei and exhibit complex cytogenetic events during the sexual process of conjugation, which is under the control of the so-called "mating type systems". Studying conjugation in ciliates may provide insight into our understanding of the origins and evolution of sex and fertilization. In the present work, we studied in detail the sexual process of conjugation using the model species Euplotes vannus, and compared these nuclear events with those occurring in other ciliates. Our results indicate that in E. vannus: 1) conjugation requires about 75 hours to complete: the longest step is the development of the new macronucleus (ca. 64h), followed by the nuclear division of meiosis I (5h); the mitotic divisions usually take only 2h; 2) there are three prezygotic divisions (mitosis and meiosis I and II), and two of the eight resulting nuclei become pronuclei; 3) after the exchange and fusion of the pronuclei, two postzygotic divisions occur; two of the four products differentiate into the new micronucleus and macronucleus, respectively, and the parental macronucleus degenerates completely; 4) comparison of the nuclear events during conjugation in different ciliates reveals that there are generally three prezygotic divisions while the number of postzygotic divisions is highly variable. These results can serve as reference to investigate the mating type system operating in this species and to analyze genes involved in the different steps of the sexual process.
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Affiliation(s)
- Yaohan Jiang
- a Institute of Evolution and Marine Biodiversity , Ocean University of China , Qingdao , China.,b Ministry of Education , Key Laboratory of Mariculture (Ocean University of China) , Qingdao , China
| | - Tengteng Zhang
- a Institute of Evolution and Marine Biodiversity , Ocean University of China , Qingdao , China.,b Ministry of Education , Key Laboratory of Mariculture (Ocean University of China) , Qingdao , China
| | - Adriana Vallesi
- c Laboratory of Eukaryotic Microbiology and Animal Biology , University of Camerino , Camerino , Italy
| | - Xianyu Yang
- d College of Animal Science and Technology , Zhejiang A&F University , Hangzhou , China
| | - Feng Gao
- a Institute of Evolution and Marine Biodiversity , Ocean University of China , Qingdao , China.,b Ministry of Education , Key Laboratory of Mariculture (Ocean University of China) , Qingdao , China
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32
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Sheng Y, He M, Zhao F, Shao C, Miao M. Phylogenetic relationship analyses of complicated class Spirotrichea based on transcriptomes from three diverse microbial eukaryotes: Uroleptopsis citrina, Euplotes vannus and Protocruzia tuzeti. Mol Phylogenet Evol 2018; 129:338-345. [DOI: 10.1016/j.ympev.2018.06.025] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Accepted: 06/13/2018] [Indexed: 11/25/2022]
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33
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Boscaro V, Syberg-Olsen MJ, Irwin NAT, del Campo J, Keeling PJ. What Can Environmental Sequences Tell Us About the Distribution of Low-Rank Taxa? The Case of Euplotes
(Ciliophora, Spirotrichea), Including a Description of Euplotes enigma
sp. nov. J Eukaryot Microbiol 2018; 66:281-293. [DOI: 10.1111/jeu.12669] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 07/11/2018] [Accepted: 07/14/2018] [Indexed: 02/06/2023]
Affiliation(s)
- Vittorio Boscaro
- Department of Botany; University of British Columbia; 3529-6270 University Boulevard Vancouver British Columbia V6T1Z4 Canada
| | - Mitchell J. Syberg-Olsen
- Department of Botany; University of British Columbia; 3529-6270 University Boulevard Vancouver British Columbia V6T1Z4 Canada
| | - Nicholas A. T. Irwin
- Department of Botany; University of British Columbia; 3529-6270 University Boulevard Vancouver British Columbia V6T1Z4 Canada
| | - Javier del Campo
- Department of Botany; University of British Columbia; 3529-6270 University Boulevard Vancouver British Columbia V6T1Z4 Canada
- Department of Marine Biology and Oceanography; Institut de Ciències del Mar - CSIC; Passeig Marítim de la Barceloneta, 37-49 08003 Barcelona Catalonia Spain
| | - Patrick J. Keeling
- Department of Botany; University of British Columbia; 3529-6270 University Boulevard Vancouver British Columbia V6T1Z4 Canada
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34
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Yan Y, Fan Y, Luo X, El-Serehy HA, Bourland W, Chen X. New contribution to the species-rich genus Euplotes: Morphology, ontogeny and systematic position of two species (Ciliophora; Euplotia). Eur J Protistol 2018; 64:20-39. [PMID: 29621653 DOI: 10.1016/j.ejop.2018.03.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 03/02/2018] [Accepted: 03/12/2018] [Indexed: 10/17/2022]
Abstract
The morphology, ontogeny and phylogeny of two Euplotes species, E. estuarinus sp. nov. and a population of E. platystoma Dragesco and Dragesco-Kernéis, 1986, both collected from tropical brackish waters in south China, were investigated based on living morphology, ciliary pattern and molecular data. Euplotes estuarinus sp. nov. is small (about 60 × 40 μm in vivo), has a dargyrome of the double-eurystomus type, and the transverse cirri are arranged in two groups, with two left and three right ones. The original description of the poorly known species, E. platystoma, is brief, and the species was never investigated using live observation and molecular methods Hence, we provided a detailed redescription. Some stages of their morphogenesis were observed which proceed in the same pattern as in their congeners. The new species E. estuarinus sp. nov. clusters with E. curdsi, differing only by 1 bp in their SSU rRNA gene sequences, which is likely due to the recent speciation event and the limited resolution of the SSU rRNA gene at species level in this group as the two species are clearly morphologically distinct.
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Affiliation(s)
- Ying Yan
- School of Marine Sciences, Ningbo University, Ningbo 315211, China; Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao 266003, China
| | - Yangbo Fan
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao 266003, China; School of Civil and Environment Engineering, Harbin Institute of Technology, Shenzhen 518000, China
| | - Xiaotian Luo
- Department of Biological Sciences, Boise State University, Boise 83725, USA
| | - Hamed A El-Serehy
- Department of Zoology, King Saud University, Riyadh 11451, Saudi Arabia
| | - William Bourland
- Department of Biological Sciences, Boise State University, Boise 83725, USA
| | - Xiangrui Chen
- School of Marine Sciences, Ningbo University, Ningbo 315211, China.
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