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Rajan D, Lee B, Albright A, Tang E, Maravillas A, Vargas C, Marshall WF, Cortes D. Phylogeny, morphology, and behavior of the new ciliate species Stentor stipatus. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.03.606273. [PMID: 39131352 PMCID: PMC11312564 DOI: 10.1101/2024.08.03.606273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 08/13/2024]
Abstract
The study of evolution at the cellular level traditionally has focused on the evolution of metabolic pathways, endomembrane systems, and genomes, but there has been increasing interest in evolution of more complex cellular structures and behaviors, particularly in the eukaryotes. Ciliates have major advantages for such studies due to their easily visible surface patterning and their dramatic and complex behaviors that can be easily analyzed. Among the ciliates, the genus Stentor epitomizes the features that are useful for studying evolution: they are widespread in freshwater environments, easy to visualize because of their large size, and capable of complex behaviors such as learning, decision-making, and phototaxis. Here, we introduce the discovery of a new species within this genus: Stentor stipatus, so named for their distinctive dark brown aggregates. We present morphological, phylogenetic, ecological, and behavioral characterizations of these cells. The S. stipatus clade has a bootstrap value of 93 and is phylogenetically distinct from S. amethystinus, the closest related species which shares a sequence similarity of 98.9%. S. stipatus is capable of phototaxis and can also habituate more quickly than S. coeruleus, the Stentor species in which most habituation studies have previously been conducted. These findings expand our understanding of Stentor species diversity, natural history, and demonstrate common principles of complex behavior that are present in single-celled organisms.
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Tarkington J, Zufall RA. Correlated responses to selection across diverse environments during experimental evolution of Tetrahymena thermophila. Ecol Evol 2024; 14:e11395. [PMID: 39045496 PMCID: PMC11264346 DOI: 10.1002/ece3.11395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 04/19/2024] [Accepted: 04/26/2024] [Indexed: 07/25/2024] Open
Abstract
Correlated responses to selection have long been observed and studied; however, it remains unclear when they will arise, and in what direction. To contribute to a growing understanding of correlated responses to selection, we used experimental evolution of the ciliate Tetrahymena thermophila to study direct and correlated responses in a variety of different environmental conditions. One experiment focused on adaptation to two different temperatures and the correlated responses across temperatures. Another experiment used inhibitory concentrations of a variety of compounds to test direct and correlated responses to selection. We found that all populations adapted to the environments in which they evolved. We also found many cases of correlated evolution across environments; few conditions resulted in trade-offs and many resulted in a positive correlated response. Surprisingly, in many instances, the correlated response was of a larger magnitude than the direct response. We find that ancestral fitness predicts the extent of adaptation, consistent with diminishing returns epistasis. Unexpectedly, we also find that this pattern of diminishing returns holds across environments regardless of the environment in which evolution occurs. We also found that the correlated response is asymmetric across environments, that is, the fitness of a population evolved in one environment and assayed in a second was inversely related to the fitness of a population evolved in the second environment and assayed in the first. These results support the notion that positive correlated responses to selection across environments are frequent, and worth further study.
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Affiliation(s)
- Jason Tarkington
- Department of Biology and BiochemistryUniversity of HoustonHoustonTexasUSA
- Department of GeneticsStanford UniversityStanfordCaliforniaUSA
| | - Rebecca A. Zufall
- Department of Biology and BiochemistryUniversity of HoustonHoustonTexasUSA
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3
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Jacob S, Dupont L, Haegeman B, Thierry M, Campana JLM, Legrand D, Cote J, Raffard A. Phenotypic plasticity and the effects of thermal fluctuations on specialists and generalists. Proc Biol Sci 2024; 291:20240256. [PMID: 38889786 DOI: 10.1098/rspb.2024.0256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Accepted: 04/17/2024] [Indexed: 06/20/2024] Open
Abstract
Classical theories predict that relatively constant environments should generally favour specialists, while fluctuating environments should be selected for generalists. However, theoretical and empirical results have pointed out that generalist organisms might, on the contrary, perform poorly under fluctuations. In particular, if generalism is underlaid by phenotypic plasticity, performance of generalists should be modulated by the temporal characteristics of environmental fluctuations. Here, we used experiments in microcosms of Tetrahymena thermophila ciliates and a mathematical model to test whether the period or autocorrelation of thermal fluctuations mediate links between the level of generalism and the performance of organisms under fluctuations. In the experiment, thermal fluctuations consistently impeded performance compared with constant conditions. However, the intensity of this effect depended on the level of generalism: while the more specialist strains performed better under fast or negatively autocorrelated fluctuations, plastic generalists performed better under slow or positively autocorrelated fluctuations. Our model suggests that these effects of fluctuations on organisms' performance may result from a time delay in the expression of plasticity, restricting its benefits to slow enough fluctuations. This study points out the need to further investigate the temporal dynamics of phenotypic plasticity to better predict its fitness consequences under environmental fluctuations.
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Affiliation(s)
- Staffan Jacob
- Station d'Écologie Théorique et Expérimentale, UAR2029, CNRS, Moulis 09200, France
| | - Léonard Dupont
- Station d'Écologie Théorique et Expérimentale, UAR2029, CNRS, Moulis 09200, France
| | - Bart Haegeman
- CNRS/Sorbonne Université, UMR7621 Laboratoire d'Océanographie Microbienne, Banyuls-sur-Mer, France
| | - Mélanie Thierry
- Station d'Écologie Théorique et Expérimentale, UAR2029, CNRS, Moulis 09200, France
| | - Julie L M Campana
- Station d'Écologie Théorique et Expérimentale, UAR2029, CNRS, Moulis 09200, France
| | - Delphine Legrand
- Station d'Écologie Théorique et Expérimentale, UAR2029, CNRS, Moulis 09200, France
| | - Julien Cote
- Centre de Recherche sur la Biodiversité et l'Environnement (CRBE), UMR 5300, CNRS-IRD-TINP-UT3, Toulouse 31062 Cedex 9, France
| | - Allan Raffard
- Université catholique de Louvain, Earth and Life Institute, Biodiversity Research Centre, Louvain-la-Neuve, Belgium
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Woodcock MR, Powers K, Snead K, Pellettieri J. Flatworm Transcriptomes Reveal Widespread Parasitism by Histophagous Ciliates. Genome Biol Evol 2024; 16:evae007. [PMID: 38242711 PMCID: PMC10837001 DOI: 10.1093/gbe/evae007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 01/05/2024] [Accepted: 01/11/2024] [Indexed: 01/21/2024] Open
Abstract
Unicellular ciliates like Tetrahymena are best known as free-living bacteriovores, but many species are facultative or obligate parasites. These "histophages" feed on the tissues of hosts ranging from planarian flatworms to commercially important fish and the larvae of imperiled freshwater mussels. Here, we developed a novel bioinformatics pipeline incorporating the nonstandard ciliate genetic code and used it to search for Ciliophora sequences in 34 publicly available Platyhelminthes EST libraries. From 2,615,036 screened ESTs, we identified nearly 6,000 high-confidence ciliate transcripts, supporting parasitism of seven additional flatworm species. We also cultured and identified Tetrahymena from nine terrestrial and freshwater planarians, including invasive earthworm predators from the genus Bipalium and the widely studied regeneration models Dugesia japonica and Schmidtea mediterranea. A co-phylogenetic reconstruction provides strong evidence for the coevolution of histophagous Ciliophora with their Platyhelminthes hosts. We further report the antiprotozoal aminoglycoside paromomycin expels Tetrahymena from S. mediterranea, providing new opportunities to investigate the effects of this relationship on planarian biology. Together, our findings raise the possibility that invasive flatworms constitute a novel dispersal mechanism for Tetrahymena parasites and position the Platyhelminthes as an ideal model phylum for studying the ecology and evolution of histophagous ciliates.
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Affiliation(s)
- M Ryan Woodcock
- Department of Biology, Keene State College, Keene, NH, USA
- Department of Science, Mathematics and Technology, Medaille University, Buffalo, NY, USA
- Department of Natural Science, Trocaire College, Buffalo, NY, USA
| | - Kaleigh Powers
- Department of Biology, Keene State College, Keene, NH, USA
| | - Kirsten Snead
- Department of Science, Mathematics and Technology, Medaille University, Buffalo, NY, USA
- Ira A. Fulton Schools of Engineering, Arizona State University, Tempe, AZ, USA
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5
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Jiang M, Zhou C, Wang S, Liu L, Zhang S, Wang L, Pan X. Identification of a Tetrahymena species infecting guppies, pathology, and expression of beta-tubulin during infection. Parasitol Res 2024; 123:104. [PMID: 38240890 DOI: 10.1007/s00436-024-08117-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Accepted: 01/04/2024] [Indexed: 01/23/2024]
Abstract
Tetrahymenosis is caused by the ciliated protozoan Tetrahymena and is responsible for serious economic losses to the aquaculture industry worldwide. However, information regarding the molecular mechanism leading to tetrahymenosis is limited. In previous transcriptome sequencing work, it was found that one of the two β-tubulin genes in T. pyriformis was significantly expressed in infected fish, we speculated that β-tubulin is involved in T. pyriformis infecting fish. Herein, the potential biological function of the β-tubulin gene in Tetrahymena species when establishing infection in guppies was investigated by cloning the full-length cDNA of this T. pyriformis β-tubulin (BTU1) gene. The full-length cDNA of T. pyriformis BTU1 gene was 1873 bp, and the ORF occupied 1134 bp, whereas 5' UTR 434 bp, and 3' UTR 305 bp whose poly (A) tail contained 12 bases. The predicted protein encoded by T. pyriformis BTU1 gene had a calculated molecular weight of 42.26 kDa and pI of 4.48. Moreover, secondary structure analysis and tertiary structure prediction of BTU1 protein were also conducted. In addition, morphology, infraciliature, phylogeny, and histopathology of T. pyriformis isolated from guppies from a fish market in Harbin were also investigated. Furthermore, qRT-PCR analysis and experimental infection assays indicated that the expression of BTU1 gene resulted in efficient cell proliferation during infection. Collectively, our data revealed that BTU1 is a key gene involved in T. pyriformis infection in guppies, and the findings discussed herein provide valuable insights for future studies on tetrahymenosis.
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Affiliation(s)
- Mingyue Jiang
- Laboratory of Protozoology, Harbin Normal University, Harbin, 150025, China
| | - Chunyu Zhou
- Laboratory of Protozoology, Harbin Normal University, Harbin, 150025, China
| | - Sihan Wang
- Laboratory of Protozoology, Harbin Normal University, Harbin, 150025, China
| | - Lihui Liu
- Laboratory of Protozoology, Harbin Normal University, Harbin, 150025, China
| | - Shuixian Zhang
- Panzhou No.4 Primary School, Panzhou, 553599, Guizhou Province, China
| | - Li Wang
- Laboratory of Protozoology, Harbin Normal University, Harbin, 150025, China
| | - Xuming Pan
- Laboratory of Protozoology, Harbin Normal University, Harbin, 150025, China.
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6
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Derelle R, Verdonck R, Jacob S, Huet M, Akerman I, Philippe H, Legrand D. The macronuclear genomic landscape within Tetrahymena thermophila. Microb Genom 2024; 10:001175. [PMID: 38206129 PMCID: PMC10868616 DOI: 10.1099/mgen.0.001175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Accepted: 12/19/2023] [Indexed: 01/12/2024] Open
Abstract
The extent of intraspecific genomic variation is key to understanding species evolutionary history, including recent adaptive shifts. Intraspecific genomic variation remains poorly explored in eukaryotic micro-organisms, especially in the nuclear dimorphic ciliates, despite their fundamental role as laboratory model systems and their ecological importance in many ecosystems. We sequenced the macronuclear genome of 22 laboratory strains of the oligohymenophoran Tetrahymena thermophila, a model species in both cellular biology and evolutionary ecology. We explored polymorphisms at the junctions of programmed eliminated sequences, and reveal their utility to barcode very closely related cells. As for other species of the genus Tetrahymena, we confirm micronuclear centromeres as gene diversification centres in T. thermophila, but also reveal a two-speed evolution in these regions. In the rest of the genome, we highlight recent diversification of genes coding for extracellular proteins and cell adhesion. We discuss all these findings in relation to this ciliate's ecology and cellular characteristics.
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Affiliation(s)
- Romain Derelle
- Station d’Ecologie Théorique et Expérimentale, UAR2029, CNRS, Moulis, France
- Present address: NIHR Health Protection Research Unit in Respiratory Infections, National Heart and Lung Institute, Imperial College London, London, UK
| | - Rik Verdonck
- Station d’Ecologie Théorique et Expérimentale, UAR2029, CNRS, Moulis, France
- Present address: Centre for Environmental Sciences, Environmental Biology, Hasselt University, Diepenbeek, Belgium
| | - Staffan Jacob
- Station d’Ecologie Théorique et Expérimentale, UAR2029, CNRS, Moulis, France
| | - Michèle Huet
- Station d’Ecologie Théorique et Expérimentale, UAR2029, CNRS, Moulis, France
| | - Ildem Akerman
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK
| | - Hervé Philippe
- Station d’Ecologie Théorique et Expérimentale, UAR2029, CNRS, Moulis, France
| | - Delphine Legrand
- Station d’Ecologie Théorique et Expérimentale, UAR2029, CNRS, Moulis, France
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7
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Woodcock MR, Powers K, Snead K, Pellettieri J. FLATWORM TRANSCRIPTOMES REVEAL WIDESPREAD PARASITISM BY HISTOPHAGOUS CILIATES. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.17.558123. [PMID: 37745455 PMCID: PMC10516030 DOI: 10.1101/2023.09.17.558123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
Unicellular ciliates like Tetrahymena are best known as free-living bacteriovores, but many species are facultative or obligate parasites. These 'histophages' feed on the tissues of hosts ranging from planarian flatworms to commercially important fish and the larvae of imperiled freshwater mussels. Here, we developed a novel bioinformatics pipeline incorporating the nonstandard ciliate genetic code and used it to search for Ciliophora sequences in 34 publicly available Platyhelminthes EST libraries. From 2,615,036 screened ESTs, we identified nearly 6,000 high-confidence ciliate transcripts, supporting parasitism of seven additional flatworm species. We also cultured and identified Tetrahymena from nine terrestrial and freshwater planarians, including invasive earthworm predators from the genus Bipalium and the widely studied regeneration models Dugesia japonica and Schmidtea mediterranea. A cophylogenetic reconstruction provides strong evidence for coevolution of histophagous Ciliophora with their Platyhelminthes hosts. We further report the antiprotozoal aminoglycoside paromomycin expels Tetrahymena from S. mediterranea, providing new opportunities to investigate the effects of this relationship on planarian biology. Together, our findings raise the possibility that invasive flatworms constitute a novel dispersal mechanism for Tetrahymena parasites and position the Platyhelminthes as an ideal model phylum for studying the ecology and evolution of histophagous ciliates.
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Affiliation(s)
- M. Ryan Woodcock
- Department of Biology, Keene State College, Keene, NH, USA
- Department of Science, Mathematics & Technology, Medaille University, Buffalo, NY, USA
- Department of Natural Science, Trocaire College, Buffalo, NY, USA
| | - Kaleigh Powers
- Department of Biology, Keene State College, Keene, NH, USA
| | - Kirsten Snead
- Department of Science, Mathematics & Technology, Medaille University, Buffalo, NY, USA
- Ira A. Fulton Schools of Engineering, Arizona State University, Tempe, AZ, USA
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8
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Schütte A, Stüben PE, Astrin JJ. Molecular Weevil Identification Project: A thoroughly curated barcode release of 1300 Western Palearctic weevil species (Coleoptera, Curculionoidea). Biodivers Data J 2023; 11:e96438. [PMID: 38357418 PMCID: PMC10865102 DOI: 10.3897/bdj.11.e96438] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 12/08/2022] [Indexed: 01/25/2023] Open
Abstract
The Molecular Weevil Identification project (MWI) studies the systematics of Western Palearctic weevils (superfamily Curculionoidea) in an integrative taxonomic approach of DNA barcoding, morphology and ecology. This barcode release provides almost 3600 curated CO1 sequences linked to morphological vouchers in about 1300 weevil species. The dataset is presented in statistical distance tables and as a Neighbour-Joining tree. Bayesian Inference trees are computed for the subfamilies Cryptorhynchinae, Apioninae and Ceutorhynchinae. Altogether, 18 unresolved taxonomic issues are discussed. A new barcode primer set is presented. Finally, we establish group-specific genetic distances for many weevil genera to serve as a tool in species delineation. These values are statistically based on distances between "good species" and their congeners. With this morphologically calibrated approach, we could resolve most alpha-taxonomic questions within the MWI project.
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Affiliation(s)
- André Schütte
- Leibniz Institute for the Analysis of Biodiversity Change, Museum Koenig, Bonn, Germany Leibniz Institute for the Analysis of Biodiversity Change, Museum Koenig Bonn Germany
| | - Peter E Stüben
- Curculio Institute, Mönchengladbach, Germany Curculio Institute Mönchengladbach Germany
| | - Jonas J Astrin
- Leibniz Institute for the Analysis of Biodiversity Change, Museum Koenig, Bonn, Germany Leibniz Institute for the Analysis of Biodiversity Change, Museum Koenig Bonn Germany
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9
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Cassidy-Hanley DM, Doerder FP, Hossain M, Devine C, Clark T. Molecular identification of Tetrahymena species. J Eukaryot Microbiol 2023; 70:e12936. [PMID: 35808858 PMCID: PMC9825679 DOI: 10.1111/jeu.12936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 06/29/2022] [Accepted: 07/05/2022] [Indexed: 01/29/2023]
Abstract
Mitochondrial cox1 689 bp barcodes are routinely used for identification of Tetrahymena species. Here, we examine whether two shorter nuclear sequences, the 5.8S rRNA gene region and the intergenic region between H3 and H4 histone genes, might also be useful either singly or in combination with each other or cox1. We obtained sequences from ~300 wild isolates deposited at the Tetrahymena Stock Center and analyzed additional sequences obtained from GenBank. The 5.8S rRNA gene and portions of its transcribed flanks identify isolates as to their major clade and uniquely identify some, but not all, species. The ~330 bp H3/H4 intergenic region possesses low intraspecific variability and is unique for most species. However, it fails to distinguish between two pairs of common species and their rarer counterparts, and its use is complicated by the presence of duplicate genes in some species. The results show that while the cox1 sequence is the best single marker for Tetrahymena species identification, 5.8S rRNA, and the H3/H4 intergenic regions sequences are useful, singly or in combination, to confirm cox1 species assignments or as part of a preliminary survey of newly collected Tetrahymena. From our newly collected isolates, the results extend the biogeographical range of T. shanghaiensis and T. malaccensis and identify a new species, Tetrahymena arleneae n. sp. herein described.
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Affiliation(s)
| | - F. Paul Doerder
- Department of Biological, Geological, and Environmental Sciences, Cleveland State University, Cleveland OH 44115
| | - Mozammal Hossain
- Department of Veterinary Medicine, Cornell University, Ithaca NY 14853-0001
| | - Catherine Devine
- Department of Veterinary Medicine, Cornell University, Ithaca NY 14853-0001
| | - Theodore Clark
- Department of Veterinary Medicine, Cornell University, Ithaca NY 14853-0001
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10
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Zhang G, Sheng Y, Liu Y, Cao X, Al-Farraj SA, Vďačný P, Pan H. Integrative studies on three new freshwater Amphileptus species (Ciliophora, Pleurostomatida) discovered in northern China. MARINE LIFE SCIENCE & TECHNOLOGY 2022; 4:452-470. [PMID: 37078086 PMCID: PMC10077290 DOI: 10.1007/s42995-022-00143-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 08/23/2022] [Indexed: 05/03/2023]
Abstract
The morphology and molecular phylogeny of freshwater pleurostomatid ciliates are insufficiently explored. In the present study, we investigated three new Amphileptus species discovered in Lake Weishan and its vicinity, northern China, using standard alpha-taxonomic methods. Amphileptus paracarchesii sp. nov. is characterized by a lateral fossa (groove) in the posterior body portion, four macronuclear nodules, contractile vacuoles distributed along the dorsal margin, and 4-6 left and 44-50 right somatic kineties. Amphileptus pilosus sp. nov. differs from congeners by having 4-14 macronuclear nodules, numerous contractile vacuoles scattered throughout the cytoplasm, and 22-31 left and 35-42 right somatic kineties. Amphileptus orientalis sp. nov. is characterized by two ellipsoidal macronuclear nodules, three ventral contractile vacuoles, and about four left and 31-35 right somatic kineties. Phylogenetic analyses of nuclear small subunit ribosomal DNA (SSU rDNA) sequences indicate that the family Amphileptidae might be monophyletic while the genus Amphileptus is paraphyletic, as Pseudoamphileptus macrostoma robustly groups with Amphileptus sp. Although deep phylogenetic relationships of amphileptids are poorly resolved, multiple well-delimited species groups are recognizable within the genus Amphileptus. Supplementary Information The online version contains supplementary material available at 10.1007/s42995-022-00143-0.
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Affiliation(s)
- Gongaote Zhang
- Engineering Research Center of Environmental DNA and Ecological Water Health Assessment, Shanghai Ocean University, Shanghai, 201306 China
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
| | - Yalan Sheng
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, School of Life Science, South China Normal University, Guangzhou, 510631 China
| | - Yujie Liu
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
| | - Xiao Cao
- Weishan Fishery Development Service Center, Jining, 277600 China
| | - Saleh A. Al-Farraj
- Zoology Department, College of Science, King Saud University, Riyadh, 11451 Saudi Arabia
| | - Peter Vďačný
- Department of Zoology, Comenius University in Bratislava, Bratislava, 84215 Slovakia
| | - Hongbo Pan
- Engineering Research Center of Environmental DNA and Ecological Water Health Assessment, Shanghai Ocean University, Shanghai, 201306 China
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11
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Study on Analysis of Several Molecular Identification Methods for Ciliates of Colpodea (Protista, Ciliophora). Cell Microbiol 2022. [DOI: 10.1155/2022/4017442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The application of molecular techniques to accurately identify protozoan species can correct previous misidentifications based on traditional morphological identification. Colpodea ciliates have many toxicological and cytological applications, but their subtle morphological differences and small body size hinder species delineation. Herein, we used Cox I and β-tubulin genes, alongside fluorescence in situ hybridization (FISH), to evaluate each method in delineating Colpodea species. For this analysis, Colpoda harbinensis n. sp., C. reniformis, two populations of C. inflata, Colpoda compare grandis, and five populations of Paracolpoda steinii, from the soil in northeastern China, were used. We determined that (1) the Cox I gene was more suitable than the β-tubulin gene as a molecular marker for defining intra- and interspecific level relationships of Colpoda. (2) FISH probes designed for Colpoda sp., C. inflata, Colpoda compare grandis, and Paracolpoda steinii, provided rapid interspecific differentiation of Colpodea species. (3) Colpoda harbinensis n. sp. was established and mainly characterized by its size in vivo (approximately
), a reniform body in outline, one macronucleus, its spherical shape, a sometimes nonexistent micronucleus, 11–15 somatic kineties, and five or six postoral kineties. In conclusion, combining oligonucleotide probes, DNA barcoding, and morphology for the first time, we have greatly improved the delineation of Colpodea and confirmed that Cox I gene was a promising DNA barcoding marker for species of Colpodea, and FISH could provide useful morphological information as complementing traditional techniques such as silver carbonate.
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12
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McGee A, Zufall RA. THE ROLE OF PRIORITY IN DETERMINING THE RESTRICTED DISTRIBUTION OF TETRAHYMENA THERMOPHILA. SOUTHWEST NAT 2022. [DOI: 10.1894/0038-4909-66.1.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Amberly McGee
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA
| | - Rebecca A. Zufall
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA
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13
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Rataj M, Zhang T, Vd’ačný P. Nuclear and Mitochondrial SSU rRNA Genes Reveal Hidden Diversity of Haptophrya Endosymbionts in Freshwater Planarians and Challenge Their Traditional Classification in Astomatia. Front Microbiol 2022; 13:830951. [PMID: 35495648 PMCID: PMC9048206 DOI: 10.3389/fmicb.2022.830951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 03/18/2022] [Indexed: 11/13/2022] Open
Abstract
Like many other aquatic animals, freshwater planarians have also become partners of symbiotic ciliates from the class Oligohymenophorea. In the present study, we explored the hidden diversity and addressed the questionable systematic position of mouthless obligatory gut endosymbionts of freshwater planarians, using the nuclear and mitochondrial SSU rRNA genes. Although all isolated ciliates morphologically corresponded to a single species, molecular analyses suggested the existence of three genetically distinct entities: Haptophrya planariarum, Haptophrya dugesiarum nov. spec., and Haptophrya schmidtearum nov. spec. The two former species share the same planarian host, which indicates a speciation model involving one duplication event without host switching. Such a diversification pattern was recognized also in astome ciliates inhabiting megascolecid and glossoscolecid earthworms. The present multi-gene phylogenies along with the secondary structure of the mitochondrial 16S rRNA molecule, however, challenge the traditional classification of Haptophrya within the subclass Astomatia. Haptophrya very likely evolved from an orphan scuticociliate lineage by the loss of oral apparatus and by the transformation of the thigmotactic field into an adhesive sucker. Since astomy evolved multiple times independently within the Oligohymenophorea, the loss of cell mouth cannot be used as a sole argument for the assignment of Haptophrya to the Astomatia anymore.
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Affiliation(s)
| | | | - Peter Vd’ačný
- Department of Zoology, Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia
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14
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Montagnes DJS, Wang Q, Lyu Z, Shao C. Evaluating thermal performance of closely related taxa: Support for hotter is not better, but for unexpected reasons. ECOL MONOGR 2022. [DOI: 10.1002/ecm.1517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- David J. S. Montagnes
- Department of Ecology Jinan University Guangzhou China
- Laboratory of Protozoological Biodiversity and Evolution in Wetland College of Life Sciences, Shaanxi Normal University Xi’an China
- Department of Evolution, Ecology and Behaviour University of Liverpool, BioSciences Building, Crown Street Liverpool UK
| | - Qing Wang
- Department of Ecology Jinan University Guangzhou China
| | - Zhao Lyu
- College of Life Sciences Northwest University Xi'an China
| | - Chen Shao
- Laboratory of Protozoological Biodiversity and Evolution in Wetland College of Life Sciences, Shaanxi Normal University Xi’an China
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15
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Rataj M, Vďačný P. Putative ITS2 secondary structure model and multi‐gene phylogenies of tetrahymenids (Ciliophora, Hymenostomatia) parasitizing planarians and crayfish worms. ZOOL SCR 2022. [DOI: 10.1111/zsc.12528] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Matej Rataj
- Department of Zoology Faculty of Natural Sciences Comenius University in Bratislava Bratislava Slovakia
| | - Peter Vďačný
- Department of Zoology Faculty of Natural Sciences Comenius University in Bratislava Bratislava Slovakia
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16
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Paramecium bursaria—A Complex of Five Cryptic Species: Mitochondrial DNA COI Haplotype Variation and Biogeographic Distribution. DIVERSITY 2021. [DOI: 10.3390/d13110589] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Ciliates are a diverse protistan group and many consist of cryptic species complexes whose members may be restricted to particular biogeographic locations. Mitochondrial genes, characterized by a high resolution for closely related species, were applied to identify new species and to distinguish closely related morphospecies. In the current study, we analyzed 132 sequences of COI mtDNA fragments obtained from P. bursaria species collected worldwide. The results allowed, for the first time, to generate a network of COI haplotypes and demonstrate the relationships between P. bursaria strains, as well as to confirm the existence of five reproductively isolated haplogroups. The P. bursaria haplogroups identified in the present study correspond to previously reported syngens (R1, R2, R3, R4, and R5), thus we decided to propose the following binominal names for each of them: P. primabursaria, P. bibursaria, P. tribursaria, P. tetrabursaria, and P. pentabursaria, respectively. The phylogeographic distribution of P. bursaria species showed that P. primabursaria and P. bibursaria were strictly Eurasian, except for two South Australian P. bibursaria strains. P. tribursaria was found mainly in Eastern Asia, in two stands in Europe and in North America. In turn, P. tetrabursaria was restricted to the USA territory, whereas P. pentabursaria was found in two European localities.
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17
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Pecina L, Vďačný P. DNA barcoding and coalescent-based delimitation of endosymbiotic clevelandellid ciliates (Ciliophora: Clevelandellida): a shift to molecular taxonomy in the inventory of ciliate diversity in panesthiine cockroaches. Zool J Linn Soc 2021. [DOI: 10.1093/zoolinnean/zlab063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
Phylogenetically distinct lineages may be hidden behind identical or highly similar morphologies. The phenomenon of morphological crypticity has been recently detected in symbiotic ciliates of the family Clevelandellidae, as multivariate and Fourier shape analyses failed to distinguish genetically distinct taxa. To address the question of species boundaries, the phylogenetic information contained in the rDNA cistron of clevelandellid ciliates, which had been isolated from the digestive tract of blaberid cockroaches, was studied using a multifaceted statistical approach. Multigene phylogenies revealed that the genus Clevelandella is paraphyletic containing members of the genus Paraclevelandia. To resolve the paraphyly of Clevelandella, two new genera, Anteclevelandella gen. nov. and Rhynchoclevelandella gen. nov., are proposed based on morphological synapomorphies and shared molecular characters. Multigene analyses and Bayesian species delimitation supported the existence of 13 distinct species within the family Clevelandellidae, eight of which represent new taxa. Moreover, two new Nyctotherus species were recognized within the clade that is sister to the Clevelandellidae. According to the present distance and network analyses, the first two domains of the 28S rRNA gene showed much higher power for species discrimination than the 18S rRNA gene and ITS region. Therefore, the former molecular marker was proposed to be a suitable group-specific barcode for the family Clevelandellidae.
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Affiliation(s)
- Lukáš Pecina
- Department of Zoology, Faculty of Natural Sciences, Comenius University in Bratislava, 842 15 Bratislava, Slovakia
| | - Peter Vďačný
- Department of Zoology, Faculty of Natural Sciences, Comenius University in Bratislava, 842 15 Bratislava, Slovakia
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Watt A, Young N, Haites R, Dunse K, Russell D, Billman-Jacobe H. Intraspecies Variation in Tetrahymena rostrata. Microorganisms 2021; 9:microorganisms9102100. [PMID: 34683421 PMCID: PMC8538936 DOI: 10.3390/microorganisms9102100] [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: 07/16/2021] [Revised: 09/21/2021] [Accepted: 09/27/2021] [Indexed: 11/19/2022] Open
Abstract
Two distinct isolates of the facultative parasite, Tetrahymena rostrata were compared, identifying and utilising markers that are useful for studying clonal variation within the species were identified and utilised. The sequences of mitochondrial genomes and several nuclear genes were determined using Illumina short read sequencing. The two T. rostrata isolates had similar morphology. The linear mitogenomes had the gene content and organisation typical of the Tetrahymena genus, comprising 8 tRNA genes, 6 ribosomal RNA genes and 45 protein coding sequences (CDS), twenty-two of which had known function. The two isolates had nucleotide identity within common nuclear markers encoded within the histone H3 and H4 and small subunit ribosomal RNA genes and differed by only 2–4 nucleotides in a region of the characterised actin genes. Variation was observed in several mitochondrial genes and was used to determine intraspecies variation and may reflect the natural history of T. rostrata from different hosts or the geographic origins of the isolates.
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Affiliation(s)
- Anne Watt
- Asia-Pacific Centre for Animal Health, Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, VIC 3010, Australia; (A.W.); (R.H.); (D.R.)
| | - Neil Young
- Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, VIC 3010, Australia; (N.Y.); (K.D.)
| | - Ruth Haites
- Asia-Pacific Centre for Animal Health, Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, VIC 3010, Australia; (A.W.); (R.H.); (D.R.)
| | - Kerry Dunse
- Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, VIC 3010, Australia; (N.Y.); (K.D.)
| | - Derek Russell
- Asia-Pacific Centre for Animal Health, Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, VIC 3010, Australia; (A.W.); (R.H.); (D.R.)
| | - Helen Billman-Jacobe
- Asia-Pacific Centre for Animal Health, Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, VIC 3010, Australia; (A.W.); (R.H.); (D.R.)
- Correspondence:
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Tarkington J, Zufall RA. Temperature affects the repeatability of evolution in the microbial eukaryote Tetrahymena thermophila. Ecol Evol 2021; 11:13139-13152. [PMID: 34646458 PMCID: PMC8495795 DOI: 10.1002/ece3.8036] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 07/29/2021] [Accepted: 08/03/2021] [Indexed: 11/09/2022] Open
Abstract
Evolutionary biologists have long sought to understand what factors affect the repeatability of adaptive outcomes. To better understand the role of temperature in determining the repeatability of adaptive trajectories, we evolved populations of different genotypes of the ciliate Tetrahymena thermophila at low and high temperatures and followed changes in growth rate over 6,500 generations. As expected, growth rate increased with a decelerating rate for all populations; however, there were differences in the patterns of evolution at the two temperatures. The growth rates of the different genotypes tended to converge as evolution proceeded at both temperatures, but this convergence was quicker and more pronounced at the higher temperature. Additionally, over the first 4,000 generations we found greater repeatability of evolution, in terms of change in growth rate, among replicates of the same genotype at the higher temperature. Finally, we found limited evidence of trade-offs in fitness between temperatures, and an asymmetry in the correlated responses, whereby evolution in a high temperature increases growth rate at the lower temperature significantly more than the reverse. These results demonstrate the importance of temperature in determining the repeatability of evolutionary trajectories for the eukaryotic microbe Tetrahymena thermophila and may provide clues to how temperature affects evolution more generally.
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Affiliation(s)
- Jason Tarkington
- Department of Biology and BiochemistryUniversity of HoustonHoustonTXUSA
- Department of GeneticsStanford UniversityStanfordCAUSA
| | - Rebecca A. Zufall
- Department of Biology and BiochemistryUniversity of HoustonHoustonTXUSA
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20
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Wang Z, Liu M, Ma H, Lu B, Shen Z, Mu C, Alfarraj SA, El-Serehy HA, Warren A. Redescription and molecular characterization of two Trichodina species (Ciliophora, Peritrichia, Mobilida) from freshwater fish in China. Parasitol Int 2021; 86:102470. [PMID: 34560288 DOI: 10.1016/j.parint.2021.102470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 09/17/2021] [Accepted: 09/17/2021] [Indexed: 10/20/2022]
Abstract
During an investigation of parasitic ciliates in northern China, two Trichodina species, T. acuta Lom, 1970 and T. nigra Lom, 1960, were isolated from the freshwater fish Cyprinus carpio Linnaeus, 1758. The morphology of each species was investigated based on dry silver nitrate-stained specimens. In addition, the molecular phylogeny of each was analyzed based on small subunit ribosomal DNA (SSU rDNA) sequence data. Trichodina acuta can be distinguished from its congeners by the undefined periphery of the central circle, the distinct gap between the rays and the central circle, and the distinctly sickle-shaped blades. Trichodina nigra is a cosmopolitan ciliate and is characterized by its densely linked denticles, broad, rounded spatula-shaped blades, robust central parts, and well developed rays. Phylogenetic analyses revealed that T. acuta and T. nigra nest within different clades, supporting the assertion that the GC content of SSU rDNA sequences could reflect evolutionary relationships among Trichodina species.
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Affiliation(s)
- Zhe Wang
- Institute of Evolution & Marine Biodiversity, Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao 266003, China
| | - Mingjian Liu
- Institute of Evolution & Marine Biodiversity, Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao 266003, China
| | - Hongang Ma
- Institute of Evolution & Marine Biodiversity, Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao 266003, China
| | - Borong Lu
- Institute of Evolution & Marine Biodiversity, Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao 266003, China.
| | - Zhuo Shen
- Institute of Microbial Ecology and Matter Cycle, School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China; Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519000, China.
| | - Changjun Mu
- Weishan Special Aquaculture Base, Jining 277600, China
| | - Saleh A Alfarraj
- 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
| | - Alan Warren
- Department of Life Sciences, Natural History Museum, London SW7 5BD, UK
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21
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Multiple independent losses of cell mouth in phylogenetically distant endosymbiotic lineages of oligohymenophorean ciliates: A lesson from Clausilocola. Mol Phylogenet Evol 2021; 166:107310. [PMID: 34506949 DOI: 10.1016/j.ympev.2021.107310] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 09/02/2021] [Accepted: 09/04/2021] [Indexed: 01/27/2023]
Abstract
The cell mouth is a property of the vast majority of free-living and endosymbiotic/epibiotic ciliates of the class Oligohymenophorea. Cytostome, however, naturally absents in the whole endosymbiotic subclass Astomatia and was naturally or experimentally lost in a few members of the subclass Hymenostomatia. This poses a question of how homoplastic might be the lack of oral structures in the oligohymenophorean evolution. To address this question, we used two mitochondrial genes, five nuclear markers, and detailed morphological data from an enigmatic mouthless ciliate, Clausilocola apostropha, which we re-discovered after more than half of a century. According to the present phylogenetic analyses, astomy evolved at least three times independently and in different time frames of the oligohymenophorean phylogeny, ranging from the Paleozoic to the Cenozoic period. Mouthless endosymbionts inhabiting mollusks (represented by Clausilocola), planarians (Haptophrya), and annelids ('core' astomes) never clustered together. Haptophrya grouped with the scuticociliate genus Conchophthirus, 'core' astomes were placed in a sister position to the scuticociliate orders Philasterida and Pleuronematida, and Clausilocola was robustly nested within the hymenostome family Tetrahymenidae. The tetrahymenid origin of Clausilocola is further corroborated by the existence of mouthless Tetrahymena mutants and the huge phenotypic plasticity in the cytostome size in tetrahymenids.
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22
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Jacob S, Legrand D. Phenotypic plasticity can reverse the relative extent of intra- and interspecific variability across a thermal gradient. Proc Biol Sci 2021; 288:20210428. [PMID: 34187192 DOI: 10.1098/rspb.2021.0428] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Intra- and interspecific variability can both ensure ecosystem functions. Generalizing the effects of individual and species assemblages requires understanding how much within and between species trait variation is genetically based or results from phenotypic plasticity. Phenotypic plasticity can indeed lead to rapid and important changes of trait distributions, and in turn community functionality, depending on environmental conditions, which raises a crucial question: could phenotypic plasticity modify the relative importance of intra- and interspecific variability along environmental gradients? We quantified the fundamental niche of five genotypes in monocultures for each of five ciliate species along a wide thermal gradient in standardized conditions to assess the importance of phenotypic plasticity for the level of intraspecific variability compared to differences between species. We showed that phenotypic plasticity strongly influences trait variability and reverses the relative extent of intra- and interspecific variability along the thermal gradient. Our results show that phenotypic plasticity may lead to either increase or decrease of functional trait variability along environmental gradients, making intra- and interspecific variability highly dynamic components of ecological systems.
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Affiliation(s)
- Staffan Jacob
- Station d'Ecologie Théorique et Expérimentale du CNRS UAR5321, 2 route du CNRS, 09200, Moulis, France
| | - Delphine Legrand
- Station d'Ecologie Théorique et Expérimentale du CNRS UAR5321, 2 route du CNRS, 09200, Moulis, France
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23
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Description of Lepidochaetus tirjakovae sp. nov. (Gastrotricha: Paucitubulatina: Chaetonotidae), using morphology and DNA barcoding. ZOOL ANZ 2021. [DOI: 10.1016/j.jcz.2021.04.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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24
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Zhang T, Vďačný P. A discovery of two new Tetrahymena species parasitizing slugs and mussels: morphology and multi-gene phylogeny of T. foissneri sp. n. and T. unionis sp. n. Parasitol Res 2021; 120:2595-2616. [PMID: 33851248 DOI: 10.1007/s00436-021-07152-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 04/04/2021] [Indexed: 11/25/2022]
Abstract
The presence of parasitic ciliates of the hymenostome genus Tetrahymena was examined in 150 mollusks belonging to six bivalve and 13 gastropod species in Slovakia, Central Europe. Tetrahymenids were detected only in two species, viz., in the invasive Lusitanian slug (Arion vulgaris) and in the native swollen river mussel (Unio tumidus). Although only 10.52% of the examined mollusk taxa were positive, their Tetrahymena infections were very intensive accounting for several hundreds of ciliates per host. Phylogenetic analyses of the 16S and 18S rRNA genes as well as of the barcoding region of the gene encoding for cytochrome c oxidase subunit I revealed that both isolates represent new taxa, T. foissneri sp. n. and T. unionis sp. n. The former species belongs to the 'borealis' clade and its nearest relative is T. limacis, a well-known parasite of slugs and snails. Besides molecular data, T. foissneri can be distinguished from T. limacis also morphologically by the body shape of the parasitic-phase form, dimensions of micronuclei, and the silverline system. On the other hand, T. unionis was classified within the 'paravorax' clade along with T. pennsylvaniensis, T. glochidiophila, and T. nigricans. Although these four species are genetically distinct, T. unionis could be morphologically separated only from T. nigricans by body shape and size. The present study suggests that both aquatic and terrestrial mollusks represent interesting hosts for the discovery of novel Tetrahymena lineages.
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Affiliation(s)
- Tengyue Zhang
- Department of Zoology, Faculty of Natural Sciences, Comenius University in Bratislava, 842 15, Bratislava, Slovakia
| | - Peter Vďačný
- Department of Zoology, Faculty of Natural Sciences, Comenius University in Bratislava, 842 15, Bratislava, Slovakia.
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25
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Rataj M, Vd'ačný P. Cryptic host-driven speciation of mobilid ciliates epibiotic on freshwater planarians. Mol Phylogenet Evol 2021; 161:107174. [PMID: 33831547 DOI: 10.1016/j.ympev.2021.107174] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 03/28/2021] [Accepted: 03/30/2021] [Indexed: 01/18/2023]
Abstract
Mobilids are among the most taxonomically diverse but morphologically uniform groups of epibiotic ciliates. They attach to their hosts by means of an adhesive disc as harmless commensals such as Urceolaria, or as parasites causing significant economic loss such as some Trichodina species. We investigated the diversity, species boundaries, and phylogenetic relationships of mobilids associated with freshwater planarians, using 114 new sequences of two mitochondrial (16S rRNA gene and cytochrome c oxidase gene) and five nuclear (18S rRNA gene, ITS1-5.8S-ITS2 region, D1/D2 domains of 28S rRNA gene) markers. Although the morphological disparity of the isolated trichodinids and urceolariids was low, Bayesian coalescent analyses revealed the existence of five distinct evolutionary lineages/species given the seven molecular markers. The occurrence of mobilids perfectly correlated with their planarian hosts: Trichodina steinii and two Urceolaria mitra-like taxa were associated exclusively with the planarian Dugesia gonocephala, Trichodina polycelis sp. n. with the planarian Polycelis felina, and Trichodina schmidtea sp. n. with the planarian Schmidtea polychroa. Host organisms thus very likely constitute sharply isolated niches that might permit speciation of their epibiotic ciliates, even though no distinct morphological features appear to be recognizable among ciliates originating from different hosts.
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Affiliation(s)
- Matej Rataj
- Department of Zoology, Comenius University in Bratislava, 842 15 Bratislava, Slovak Republic
| | - Peter Vd'ačný
- Department of Zoology, Comenius University in Bratislava, 842 15 Bratislava, Slovak Republic.
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26
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Soo VWC, Swadling JB, Faure AJ, Warnecke T. Fitness landscape of a dynamic RNA structure. PLoS Genet 2021; 17:e1009353. [PMID: 33524037 PMCID: PMC7877785 DOI: 10.1371/journal.pgen.1009353] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 02/11/2021] [Accepted: 01/12/2021] [Indexed: 11/24/2022] Open
Abstract
RNA structures are dynamic. As a consequence, mutational effects can be hard to rationalize with reference to a single static native structure. We reasoned that deep mutational scanning experiments, which couple molecular function to fitness, should capture mutational effects across multiple conformational states simultaneously. Here, we provide a proof-of-principle that this is indeed the case, using the self-splicing group I intron from Tetrahymena thermophila as a model system. We comprehensively mutagenized two 4-bp segments of the intron. These segments first come together to form the P1 extension (P1ex) helix at the 5' splice site. Following cleavage at the 5' splice site, the two halves of the helix dissociate to allow formation of an alternative helix (P10) at the 3' splice site. Using an in vivo reporter system that couples splicing activity to fitness in E. coli, we demonstrate that fitness is driven jointly by constraints on P1ex and P10 formation. We further show that patterns of epistasis can be used to infer the presence of intramolecular pleiotropy. Using a machine learning approach that allows quantification of mutational effects in a genotype-specific manner, we demonstrate that the fitness landscape can be deconvoluted to implicate P1ex or P10 as the effective genetic background in which molecular fitness is compromised or enhanced. Our results highlight deep mutational scanning as a tool to study alternative conformational states, with the capacity to provide critical insights into the structure, evolution and evolvability of RNAs as dynamic ensembles. Our findings also suggest that, in the future, deep mutational scanning approaches might help reverse-engineer multiple alternative or successive conformations from a single fitness landscape.
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Affiliation(s)
- Valerie W. C. Soo
- Medical Research Council London Institute of Medical Sciences, London, United Kingdom
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Jacob B. Swadling
- Medical Research Council London Institute of Medical Sciences, London, United Kingdom
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Andre J. Faure
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Tobias Warnecke
- Medical Research Council London Institute of Medical Sciences, London, United Kingdom
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom
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27
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Evolution of the mating type gene pair and multiple sexes in Tetrahymena. iScience 2021; 24:101950. [PMID: 33437937 PMCID: PMC7786109 DOI: 10.1016/j.isci.2020.101950] [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: 02/25/2020] [Revised: 06/16/2020] [Accepted: 12/11/2020] [Indexed: 11/21/2022] Open
Abstract
The multiple mating type system of the Ciliate Tetrahymena thermophila is a self/non-self recognition system, whose specificity resides in a head-to-head, functionally distinct pair of genes, MTA and MTB. We have now sequenced and analyzed these mating type genes in nine additional Tetrahymena species. We conclude that MTA and MTB are derived from a common ancestral gene and have co-evolved for at least ∼150 Myr. We show that T. shanghaiensis, a perpetual selfer (unisexual) species, has a single mating type gene pair, whose MTA and MTB genes likely have different mating type specificity. We document the recent replacement of a complete different set of mating type specificities for another, illustrating how quickly this can happen. We discuss how varying conditions of reproductive stress could result in evolutionary co-adaptations of MTA and MTB genes and changes in mating type determination mechanisms. The two Tetrahymena mating type proteins evolved from a common ancestor Successive replacement waves generated the current diversity of mating type proteins Well defined segments of both mating type proteins show differential lineage sorting Perpetual selfer, T. shanghaiensis, has a heterospecific mating type gene pair
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28
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Farthing HN, Jiang J, Henwood AJ, Fenton A, Garner TWJ, Daversa DR, Fisher MC, Montagnes DJS. Microbial Grazers May Aid in Controlling Infections Caused by the Aquatic Zoosporic Fungus Batrachochytrium dendrobatidis. Front Microbiol 2021; 11:592286. [PMID: 33552011 PMCID: PMC7858660 DOI: 10.3389/fmicb.2020.592286] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 12/16/2020] [Indexed: 11/13/2022] Open
Abstract
Free-living eukaryotic microbes may reduce animal diseases. We evaluated the dynamics by which micrograzers (primarily protozoa) apply top-down control on the chytrid Batrachochytrium dendrobatidis (Bd) a devastating, panzootic pathogen of amphibians. Although micrograzers consumed zoospores (∼3 μm), the dispersal stage of chytrids, not all species grew monoxenically on zoospores. However, the ubiquitous ciliate Tetrahymena pyriformis, which likely co-occurs with Bd, grew at near its maximum rate (r = 1.7 d-1). A functional response (ingestion vs. prey abundance) for T. pyriformis, measured using spore-surrogates (microspheres) revealed maximum ingestion (I max ) of 1.63 × 103 zoospores d-1, with a half saturation constant (k) of 5.75 × 103 zoospores ml-1. Using these growth and grazing data we developed and assessed a population model that incorporated chytrid-host and micrograzer dynamics. Simulations using our data and realistic parameters obtained from the literature suggested that micrograzers could control Bd and potentially prevent chytridiomycosis (defined as 104 sporangia host-1). However, simulated inferior micrograzers (0.7 × I max and 1.5 × k) did not prevent chytridiomycosis, although they ultimately reduced pathogen abundance to below levels resulting in disease. These findings indicate how micrograzer responses can be applied when modeling disease dynamics for Bd and other zoosporic fungi.
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Affiliation(s)
- Hazel N. Farthing
- Shanghai Universities Key Laboratory of Marine Animal Taxonomy and Evolution, Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, China
- Department of Evolution, Ecology and Behaviour, Biosciences Building, University of Liverpool, Liverpool, United Kingdom
| | - Jiamei Jiang
- Shanghai Universities Key Laboratory of Marine Animal Taxonomy and Evolution, Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, China
| | - Alexandra J. Henwood
- Department of Evolution, Ecology and Behaviour, Biosciences Building, University of Liverpool, Liverpool, United Kingdom
| | - Andy Fenton
- Department of Evolution, Ecology and Behaviour, Biosciences Building, University of Liverpool, Liverpool, United Kingdom
| | - Trent W. J. Garner
- Institute of Zoology, Zoological Society of London, London, United Kingdom
| | - David R. Daversa
- MRC Centre for Global Infectious Disease Analysis, Imperial College London, London, United Kingdom
| | - Matthew C. Fisher
- Department of Evolution, Ecology and Behaviour, Biosciences Building, University of Liverpool, Liverpool, United Kingdom
- Institute of Zoology, Zoological Society of London, London, United Kingdom
| | - David J. S. Montagnes
- Department of Evolution, Ecology and Behaviour, Biosciences Building, University of Liverpool, Liverpool, United Kingdom
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Obert T, Rurik I, Vd’ačný P. Diversity and Eco-Evolutionary Associations of Endosymbiotic Astome Ciliates With Their Lumbricid Earthworm Hosts. Front Microbiol 2021; 12:689987. [PMID: 34220782 PMCID: PMC8250849 DOI: 10.3389/fmicb.2021.689987] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 05/06/2021] [Indexed: 12/17/2022] Open
Abstract
Coevolution of endosymbionts with their hosts plays an important role in the processes of speciation and is among the most fascinating topics in evolutionary biology. Astome ciliates represent an interesting model for coevolutionary studies because they are so tightly associated with their host organisms that they completely lost the cell oral apparatus. In the present study, we used five nuclear markers (18S rRNA gene, ITS1-5.8S-ITS2 region, and 28S rRNA gene) and two mitochondrial genes (16S rRNA gene and cytochrome c oxidase subunit I) to explore the diversity of astomes inhabiting the digestive tract of lumbricid earthworms at temperate latitudes in Central Europe and to cast more light on their host specificity and coevolution events that shaped their diversification. The present coevolutionary and phylogenetic interaction-adjusted similarity analyses suggested that almost every host switch leads to speciation and firm association with the new host. Nevertheless, the suggested high structural host specificity of astomes needs to be tested with increased earthworm sampling, as only 52 out of 735 lumbricid earthworms (7.07%) were inhabited by ciliates. On the other hand, the diversification of astomes associated with megascolecid and glossoscolecid earthworms might have been driven by duplication events without host switching.
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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: 27] [Impact Index Per Article: 6.8] [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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Morel‐Journel T, Thuillier V, Pennekamp F, Laurent E, Legrand D, Chaine AS, Schtickzelle N. A multidimensional approach to the expression of phenotypic plasticity. Funct Ecol 2020. [DOI: 10.1111/1365-2435.13667] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Thibaut Morel‐Journel
- Earth and Life Institute Biodiversity Research Centre Université catholique de Louvain Louvain‐la‐Neuve Belgium
| | - Virginie Thuillier
- Earth and Life Institute Biodiversity Research Centre Université catholique de Louvain Louvain‐la‐Neuve Belgium
| | - Frank Pennekamp
- Earth and Life Institute Biodiversity Research Centre Université catholique de Louvain Louvain‐la‐Neuve Belgium
- Department of Evolutionary Biology and Environmental Studies University of Zurich Zurich Switzerland
| | - Estelle Laurent
- Earth and Life Institute Biodiversity Research Centre Université catholique de Louvain Louvain‐la‐Neuve Belgium
| | - Delphine Legrand
- Earth and Life Institute Biodiversity Research Centre Université catholique de Louvain Louvain‐la‐Neuve Belgium
- Station d'Ecologie Théorique et Expérimentale du CNRS UMR5321 Moulis France
| | - Alexis S. Chaine
- Station d'Ecologie Théorique et Expérimentale du CNRS UMR5321 Moulis France
- Toulouse School of Economics Institute for Advanced Studies in Toulouse Toulouse France
| | - Nicolas Schtickzelle
- Earth and Life Institute Biodiversity Research Centre Université catholique de Louvain Louvain‐la‐Neuve Belgium
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Agatha S, Utz LRP, Zufall RA, Warren A. Symposium on Ciliates in Memory of Denis Lynn. Eur J Protistol 2020; 78:125694. [PMID: 33500175 DOI: 10.1016/j.ejop.2020.125694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 03/10/2020] [Indexed: 10/24/2022]
Abstract
Denis Lynn (1947-2018) was an outstanding protistologist, applying multiple techniques and data sources and thus pioneering an integrative approach in order to investigate ciliate biology. For example, he recognized the importance of the ultrastructure for inferring ciliate phylogeny, based on which he developed his widely accepted classification scheme for the phylum Ciliophora. In this paper, recent findings regarding the evolution and systematics of both peritrichs and the mainly marine planktonic oligotrichean spirotrichs are discussed and compared with the concepts and hypotheses formulated by Denis Lynn. Additionally, the state of knowledge concerning the diversity of ciliates in bromeliad phytotelmata and amitosis in ciliates is reviewed.
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Affiliation(s)
- Sabine Agatha
- Department of Biosciences, Paris Lodron University of Salzburg, Salzburg, Austria.
| | - Laura R P Utz
- School of Health and Life Sciences, PUCRS, Porto Alegre, Brazil
| | - Rebecca A Zufall
- Department of Biology and Biochemistry, University of Houston, Houston, TX, USA
| | - Alan Warren
- Department of Life Sciences, Natural History Museum, London, UK.
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Multi-gene phylogeny of Tetrahymena refreshed with three new histophagous species invading freshwater planarians. Parasitol Res 2020; 119:1523-1545. [PMID: 32152714 DOI: 10.1007/s00436-020-06628-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 02/14/2020] [Indexed: 10/24/2022]
Abstract
Planarians represent an insufficiently explored group of aquatic invertebrates that might serve as hosts of histophagous ciliates belonging to the hymenostome genus Tetrahymena. During our extensive research on freshwater planarians, parasitic tetrahymenas were detected in two of the eight planarian species investigated, namely, in Dugesia gonocephala and Girardia tigrina. Using the 16S and 18S rRNA genes as well as the barcoding cytochrome oxidase subunit I, one ciliate species was identified as T. scolopax and three species were recognized as new forms: T. acanthophora, T. dugesiae, and T. nigricans. Thus, 25% of the examined planarian taxa are positive for Tetrahymena species and three of them represent new taxa, indicating a large undescribed ciliate diversity in freshwater planarians. According to phylogenetic analyses, histophagous tetrahymenas show a low phylogenetic host specificity. Although T. acanthophora, T. dugesiae, and T. scolopax clustered together within the "borealis" clade, the former species has been detected exclusively in G. tigrina, while the two latter species only in D. gonocephala. Tetrahymena nigricans, which has been isolated only from G. tigrina, was classified within the "paravorax" clade along with T. glochidiophila which feeds on glochidia. The present phylogenetic reconstruction of ancestral life strategies suggested that the last common ancestor of the family Tetrahymenidae was free-living, unlike the progenitor of the subclass Hymenostomatia which was very likely parasitic. Consequently, there were at least seven independent shifts back to parasitism/histophagy within Tetrahymena: one each in the "paravorax" and "australis" clades and at least five transfers back to parasitism in the "borealis" clade.
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Documentation of a new hypotrich species in the family Amphisiellidae, Lamtostyla gui n. sp. (Protista, Ciliophora) using a multidisciplinary approach. Sci Rep 2020; 10:3763. [PMID: 32111909 PMCID: PMC7048753 DOI: 10.1038/s41598-020-60327-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 02/11/2020] [Indexed: 01/04/2023] Open
Abstract
An integrated approach considering both morphologic and molecular data is now required to improve biodiversity estimations and provide more robust systematics interpretations in hypotrichs, a highly differentiated group of ciliates. In present study, we document a new hypotrich species, Lamtostyla gui n. sp., collected from Chongming wetland, Shanghai, China, based on investigations using living observation, protargol staining, scanning and transmission electron microscopy, and gene sequencing. The new species is mainly recognized by having a short amphisiellid median cirral row composed of four cirri, three frontoventral cirri, three dorsal kinetids, four to eight macronuclear nodules, and small colorless cortical granules distributed as rosettes around dorsal bristles. Transmission electron microscope observation finds the associated microtubules of cirri and pharyngeal discs of L. gui are distinct from those in other hypotrichs. Morphogenesis of this species indicates that parental adoral membranelles retained intact or partial renewed is a potential feature to separate Lamtostyla granulifera-group and Lamtostyla lamottei-group. Phylogenetic analysis based on small subunit ribosomal RNA (rRNA) gene shows that this molecular marker is not useful to resolve phylogenetic relationships of the genus Lamtostyla, as well as many other hypotrichous taxa. We additionally characterize the internal transcribed spacers (ITS) region and the almost complete large subunit rRNA, which will be essential for future studies aimed at solving phylogenetic problems of Lamtostyla, or even the family Amphisiellidae. As a final remark, the critical screening of GenBank using ITS genes of our organism allows us to recognize a large amount of hypotrichous sequences have been misclassified as fungi. This observation suggests that hypotrichs could be frequently found in fungi-rich environment and overlooked by fungal specialists.
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Abundant and diverse Tetrahymena species living in the bladder traps of aquatic carnivorous Utricularia plants. Sci Rep 2019; 9:13669. [PMID: 31541152 PMCID: PMC6754427 DOI: 10.1038/s41598-019-50123-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 09/06/2019] [Indexed: 01/01/2023] Open
Abstract
Ciliates are unicellular eukaryotes known for their cellular complexity and wide range of natural habitats. How they adapt to their niches and what roles they play in ecology remain largely unknown. The genus Tetrahymena is among the best-studied groups of ciliates and one particular species, Tetrahymena thermophila, is a well-known laboratory model organism in cell and molecular biology, making it an excellent candidate for study in protist ecology. Here, based on cytochrome c oxidase subunit I (COX1) gene barcoding, we identify a total of 19 different putative Tetrahymena species and two closely related Glaucoma lineages isolated from distinct natural habitats, of which 13 are new species. These latter include 11 Tetrahymena species found in the bladder traps of Utricularia plants, the most species-rich and widely distributed aquatic carnivorous plant, thus revealing a previously unknown but significant symbiosis of Tetrahymena species living among the microbial community of Utricularia bladder traps. Additional species were collected using an artificial trap method we have developed. We show that diverse Tetrahymena species may live even within the same habitat and that their populations are highly dynamic, suggesting that the diversity and biomass of species worldwide is far greater than currently appreciated.
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Rataj M, Vdacny P. Living morphology and molecular phylogeny of oligohymenophorean ciliates associated with freshwater turbellarians. DISEASES OF AQUATIC ORGANISMS 2019; 134:147-166. [PMID: 31120041 DOI: 10.3354/dao03366] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Three freshwater turbellarian species (Dugesia gonocephala, Girardia tigrina, and Polycelis felina), belonging to the order Tricladida, were examined for the presence of ciliates. Living morphology and phylogenetic position of the isolated ciliates were studied using light microscopy and molecular phylogenetic methods. Three ciliate species, all from the highly diverse class Oligohymenophorea, were detected: Haptophrya planariarum from the subclass Astomatia, Urceolaria mitra from the subclass Peritrichia, and Tetrahymena sp. from the subclass Hymenostomatia. Each of these ciliates is specialized for different parts of the turbellarian bodies: H. planariarum lives in the pharynx and rami of the intestine, U. mitra colonizes the body surface, and Tetrahymena sp. attacks open wounds and feeds on the mesenchyme. Astomes and peritrichs isolated from turbellarians are placed deeper in 18S rRNA gene phylogenies than their relatives isolated from annelids and mollusks. On the other hand, Tetrahymena sp. isolated from turbellarians is classified comparatively deeply within the family Tetrahymenidae, suggesting that the phylogeny of tetrahymenids does not correlate with that of their obligate/facultative host groups. Nevertheless, the reconstruction of ancestral traits corroborated the hypothesis that histophagy was already a life history trait of the progenitor of the subclass Hymenostomatia to which Tetrahymena belongs.
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Affiliation(s)
- M Rataj
- Department of Zoology, Comenius University in Bratislava, 842 15 Bratislava, Slovakia
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