1
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Alimenti C, Pedrini B, Luporini P, Jiang Y, Vallesi A. Homo- and hetero-oligomeric protein-protein associations explain autocrine and heterologous pheromone-cell interactions in Euplotes. Eur J Protistol 2024; 94:126075. [PMID: 38520753 DOI: 10.1016/j.ejop.2024.126075] [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: 11/30/2023] [Revised: 03/11/2024] [Accepted: 03/13/2024] [Indexed: 03/25/2024]
Abstract
In Euplotes, protein pheromones regulate cell reproduction and mating by binding cells in autocrine or heterologous fashion, respectively. Pheromone binding sites (receptors) are identified with membrane-bound pheromone isoforms determined by the same genes specifying the soluble forms, establishing a structural equivalence in each cell type between the two twin proteins. Based on this equivalence, autocrine and heterologous pheromone/receptor interactions were investigated analyzing how native molecules of pheromones Er-1 and Er-13, distinctive of mating compatible E. raikovi cell types, associate into crystals. Er-1 and Er-13 crystals are equally formed by molecules that associate cooperatively into oligomeric chains rigorously taking a mutually opposite orientation, and each burying two interfaces. A minor interface is pheromone-specific, while a major one is common in Er-1 and Er-13 crystals. A close structural inspection of this interface suggests that it may be used by Er-1 and Er-13 to associate into heterodimers, yet inapt to further associate into higher complexes. Pheromone-molecule homo-oligomerization into chains accounts for clustering and internalization of autocrine pheromone/receptor complexes in growing cells, while the heterodimer unsuitability to oligomerize may explain why heterologous pheromone/receptor complexes fail clustering and internalization. Remaining on the cell surface, they are credited with a key role in cell-cell mating adhesion.
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Affiliation(s)
- Claudio Alimenti
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, MC, Italy
| | - Bill Pedrini
- Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Pierangelo Luporini
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, MC, Italy
| | - Yaohan Jiang
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, MC, Italy; Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China
| | - Adriana Vallesi
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, MC, Italy.
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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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Dong J, Liu Y, Ma J, Ma H, Stoeck T, Fan X. Ultrastructure of Diophrys appendiculata and new systematic consideration of the euplotid family Uronychiidae (Protista, Ciliophora). MARINE LIFE SCIENCE & TECHNOLOGY 2022; 4:551-568. [PMID: 37078077 PMCID: PMC10077282 DOI: 10.1007/s42995-022-00153-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 10/13/2022] [Indexed: 05/03/2023]
Abstract
The ultrastructure of ciliates carries important cytological, taxonomical, and evolutionary signals for these single-celled eukaryotic organisms. However, little ultrastructural data have been accumulated for most ciliate groups with systematic problems. In the present work, a well-known marine uronychiid, Diophrys appendiculata, was investigated using electron microscopy and a comparison with, and a discussion considering, phylogenetic analyses were made. The new findings primarily show that: (i) this species lacks the typical alveolar plate, bears cortical ampule-like extrusomes, and has microtubular triads in the dorsal pellicle, and thus exhibits some ultrastructural features in common with most of its previously studied congeners; (ii) each adoral membranelle before the level of frontal cirrus II/2 contains three rows of kinetosomes and each membranelle after the level of frontal cirrus II/2 contains four rows, which might be related with morphogenesis and could be considered as a distinctive character of Diophrys; (iii) some structural details of the buccal field, such as the extra-pellicular fibrils, pellicle, pharyngeal disks and microtubular sheet, were documented. In addition, based on the ultrastructural comparison of representatives, we discuss the differentiation between the subfamilies Diophryinae and Uronychiinae. A hypothetical systematic relationship of members in the order Euplotida based on a wide range of data is also provided.
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Affiliation(s)
- Jingyi Dong
- School of Life Sciences, East China Normal University, Shanghai, 200241 China
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
- Laoshan Laboratory, Qingdao, 266237 China
| | - Yujie Liu
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
| | - Jiyang Ma
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
| | - Honggang Ma
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
| | - Thorsten Stoeck
- Ecology Group, Technical University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Xinpeng Fan
- School of Life Sciences, East China Normal University, Shanghai, 200241 China
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4
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Analysis of autapomorphic point mutations provides a key for the tangled taxonomic distinction of the closely related species, Euplotes crassus, E. minuta and E. vannus (Ciliophora, Euplotida). Eur J Protistol 2022; 86:125917. [DOI: 10.1016/j.ejop.2022.125917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 08/19/2022] [Accepted: 08/23/2022] [Indexed: 11/17/2022]
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5
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Alimenti C, Buonanno F, Di Giuseppe G, Guella G, Luporini P, Ortenzi C, Vallesi A. Bioactive Molecules from Ciliates: Structure, Activity, and Applicative Potential. J Eukaryot Microbiol 2022; 69:e12887. [PMID: 35014102 PMCID: PMC9542385 DOI: 10.1111/jeu.12887] [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: 12/06/2021] [Accepted: 01/03/2022] [Indexed: 11/28/2022]
Abstract
Ciliates are a rich source of molecules synthesized to socialize, compete ecologically, and interact with prey and predators. Their isolation from laboratory cultures is often straightforward, permitting the study of their mechanisms of action and their assessment for applied research. This review focuses on three classes of these bioactive molecules: (i) water‐borne, cysteine‐rich proteins that are used as signaling pheromones in self/nonself recognition phenomena; (ii) cell membrane‐associated lipophilic terpenoids that are used in interspecies competitions for habitat colonization; (iii) cortical granule‐associated molecules of various chemical nature that primarily serve offence/defense functions.
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Affiliation(s)
- C Alimenti
- Laboratory of Eukaryotic Microbiology and Animal Biology, School of Biosciences and Veterinary Medicine, University of Camerino, 62032, Camerino, (MC), Italy
| | - F Buonanno
- Laboratory of Protistology and Biology Education, Department of Education, Cultural Heritage, and Tourism (ECHT), Università degli Studi di Macerata, 62100, Macerata, Italy
| | - G Di Giuseppe
- Unit of Protistology, Department of Biology, University of Pisa, 56126 Pisa, Italy; MARinePHARMA Center, University of Pisa, Italy
| | - G Guella
- Bioorganic Chemistry Lab, Department of Physics, University of Trento, 38123, Povo, Trento, Italy
| | - P Luporini
- Laboratory of Eukaryotic Microbiology and Animal Biology, School of Biosciences and Veterinary Medicine, University of Camerino, 62032, Camerino, (MC), Italy
| | - C Ortenzi
- Laboratory of Protistology and Biology Education, Department of Education, Cultural Heritage, and Tourism (ECHT), Università degli Studi di Macerata, 62100, Macerata, Italy
| | - A Vallesi
- Laboratory of Eukaryotic Microbiology and Animal Biology, School of Biosciences and Veterinary Medicine, University of Camerino, 62032, Camerino, (MC), Italy
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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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7
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Lian C, Wang Y, Jiang J, Yuan Q, Al-Farraj SA, El-Serehy HA, Song W, Stoeck T, Shao C. Systematic positions and taxonomy of two new ciliates found in China: Euplotes tuffraui sp. nov. and E. shii sp. nov. (Alveolata, Ciliophora, Euplotida). SYST BIODIVERS 2021. [DOI: 10.1080/14772000.2020.1865472] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Chunyu Lian
- Laboratory of Protozoological Biodiversity and Evolution in Wetland, College of Life Sciences, Shaanxi Normal University, Xi’an, 710119, China
- Institute of Evolution & Marine Biodiversity, and College of Fisheries, Ocean University of China, Qingdao, 266003, China
- Department of Ecology, University of Kaiserslautern, Kaiserslautern, 67663, Germany
| | - Yurui Wang
- Laboratory of Protozoological Biodiversity and Evolution in Wetland, College of Life Sciences, Shaanxi Normal University, Xi’an, 710119, China
| | - Jiamei Jiang
- Shanghai Universities Key Laboratory of Marine Animal Taxonomy and Evolution, Shanghai Ocean University, Shanghai, 201306, China
| | - Qingxiang Yuan
- Institute of Evolution & Marine Biodiversity, and College of Fisheries, Ocean University of China, 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, and College of Fisheries, Ocean University of China, Qingdao, 266003, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266003, China
| | - Thorsten Stoeck
- Department of Ecology, University of Kaiserslautern, Kaiserslautern, 67663, Germany
| | - Chen Shao
- Laboratory of Protozoological Biodiversity and Evolution in Wetland, College of Life Sciences, Shaanxi Normal University, Xi’an, 710119, China
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8
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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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9
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A barotolerant ciliate isolated from the abyssal deep sea of the North Atlantic: Euplotes dominicanus sp. n. (Ciliophora, Euplotia). Eur J Protistol 2020; 73:125664. [PMID: 31978632 DOI: 10.1016/j.ejop.2019.125664] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 12/20/2019] [Accepted: 12/22/2019] [Indexed: 11/22/2022]
Abstract
A new Euplotes species, isolated from abyssal depths (>4000 m) of the North Atlantic Ocean, was described based on morphology, ciliary pattern and molecular data. Euplotes dominicanus sp. n. is characterized by a small body size (29-40 × 17-27 μm in vivo), 18-22 adoral membranelles, 10 frontoventral, five transverse and two left marginal cirri and one caudal cirrus, five or six dorsolateral kineties with 7-9 dikinetids in mid-dorsolateral kinety (DK3), and dorsal silverline system of the double-eurystomus type. Phylogenetic analyses inferred from 18S rRNA sequences show that Euplotes dominicanus sp. n. is most closely related to E. curdsi, with a sequence similarity of 97.6 %. Euplotes dominicanus sp. n. was able to survive hydrostatic pressures up to 500 bar indicating its barotolerance. Metabarcoding data demonstrate the presence of E. dominicanus sp. n. in sediments of several deep-sea basins.
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10
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Wang R, Liu J, Di Giuseppe G, Liang A. UAA and UAG may Encode Amino Acid in Cathepsin B Gene of Euplotes octocarinatus. J Eukaryot Microbiol 2019; 67:144-149. [PMID: 31419839 DOI: 10.1111/jeu.12755] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 07/23/2019] [Accepted: 08/11/2019] [Indexed: 12/28/2022]
Abstract
The ciliate Euplotes deviates from the universal genetic code by translating UGA as cysteine and using UAA and UAG as the termination codon. Here, we cloned and sequenced the Cathepsin B gene of Euplotes octocarinatus (Eo-CTSB) which containing several in-frame stop codons throughout the coding sequence. We provide evidences, based on 3'-RACE method and Western blot, that the Eo-CTSB gene is actively expressed. Comparison of the derived amino acid sequence with the homologs in other eukaryotes revealed that UAA and UAG may code for glutamine in Eo-CTSB. These findings imply an evolutionary complexity of stop codon reassignment in eukaryotes.
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Affiliation(s)
- Ruanlin Wang
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, 030006, China
| | - Jingni Liu
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, 030006, China
| | | | - Aihua Liang
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, 030006, China
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11
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Vallesi A, Sjödin A, Petrelli D, Luporini P, Taddei AR, Thelaus J, Öhrman C, Nilsson E, Di Giuseppe G, Gutiérrez G, Villalobo E. A New Species of the γ-Proteobacterium Francisella, F. adeliensis Sp. Nov., Endocytobiont in an Antarctic Marine Ciliate and Potential Evolutionary Forerunner of Pathogenic Species. MICROBIAL ECOLOGY 2019; 77:587-596. [PMID: 30187088 DOI: 10.1007/s00248-018-1256-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 08/29/2018] [Indexed: 06/08/2023]
Abstract
The study of the draft genome of an Antarctic marine ciliate, Euplotes petzi, revealed foreign sequences of bacterial origin belonging to the γ-proteobacterium Francisella that includes pathogenic and environmental species. TEM and FISH analyses confirmed the presence of a Francisella endocytobiont in E. petzi. This endocytobiont was isolated and found to be a new species, named F. adeliensis sp. nov.. F. adeliensis grows well at wide ranges of temperature, salinity, and carbon dioxide concentrations implying that it may colonize new organisms living in deeply diversified habitats. The F. adeliensis genome includes the igl and pdp gene sets (pdpC and pdpE excepted) of the Francisella pathogenicity island needed for intracellular growth. Consistently with an F. adeliensis ancient symbiotic lifestyle, it also contains a single insertion-sequence element. Instead, it lacks genes for the biosynthesis of essential amino acids such as cysteine, lysine, methionine, and tyrosine. In a genome-based phylogenetic tree, F. adeliensis forms a new early branching clade, basal to the evolution of pathogenic species. The correlations of this clade with the other clades raise doubts about a genuine free-living nature of the environmental Francisella species isolated from natural and man-made environments, and suggest to look at F. adeliensis as a pioneer in the Francisella colonization of eukaryotic organisms.
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Affiliation(s)
- Adriana Vallesi
- School of Biosciences and Veterinary Medicine, University of Camerino, 62032, Camerino, MC, Italy.
| | - Andreas Sjödin
- Department of Chemistry, Computational Life Science Cluster (CLiC), Umeå University, Umeå, Sweden
- Division of CBRN Defence and Security, Swedish Defence Research Agency, FOI, Umeå, Sweden
| | - Dezemona Petrelli
- School of Biosciences and Veterinary Medicine, University of Camerino, 62032, Camerino, MC, Italy
| | - Pierangelo Luporini
- School of Biosciences and Veterinary Medicine, University of Camerino, 62032, Camerino, MC, Italy
| | - Anna Rita Taddei
- Center of Large Equipment-section of Electron Microscopy, University of Tuscia, Largo dell'Università, snc, Viterbo, Italy
| | - Johanna Thelaus
- Division of CBRN Defence and Security, Swedish Defence Research Agency, FOI, Umeå, Sweden
| | - Caroline Öhrman
- Division of CBRN Defence and Security, Swedish Defence Research Agency, FOI, Umeå, Sweden
| | - Elin Nilsson
- Division of CBRN Defence and Security, Swedish Defence Research Agency, FOI, Umeå, Sweden
| | | | - Gabriel Gutiérrez
- Departamento de Genética, Universidad de Sevilla, Av Reina Mercedes 6, 41012, Seville, Spain
| | - Eduardo Villalobo
- Departamento de Microbiología, Universidad de Sevilla, Av Reina Mercedes 6, 41012, Seville, Spain.
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12
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Lian C, Zhang T, Al-Rasheid KA, Yu Y, Jiang J, Huang J. Morphology and SSU rDNA-based phylogeny of two Euplotes species from China: E. wuhanensis sp. n. and E. muscicola Kahl, 1932 (Ciliophora, Euplotida). Eur J Protistol 2019; 67:1-14. [DOI: 10.1016/j.ejop.2018.10.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2018] [Revised: 10/03/2018] [Accepted: 10/05/2018] [Indexed: 11/25/2022]
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13
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Zhao Y, Yi Z, Warren A, Song W. Species delimitation for the molecular taxonomy and ecology of the widely distributed microbial eukaryote genus Euplotes (Alveolata, Ciliophora). Proc Biol Sci 2019; 285:rspb.2017.2159. [PMID: 29367393 DOI: 10.1098/rspb.2017.2159] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 01/03/2018] [Indexed: 11/12/2022] Open
Abstract
Recent advances in high-throughput sequencing and metabarcoding technologies are revolutionizing our understanding of the diversity and ecology of microbial eukaryotes (protists). The interpretation of protist diversity and the elucidation of their ecosystem function are, however, impeded by problems with species delimitation, especially as it applies to molecular taxonomy. Here, using the ciliate Euplotes as an example, we describe approaches for species delimitation based on integrative taxonomy by using evolutionary and ecological perspectives and selecting the most appropriate metabarcoding gene markers as proxies for species units. Our analyses show that: Euplotes (sensu lato) comprises six distinct clades, mainly as result of ecological speciation; the validity of the genera Euplotes (sensu stricto), Euplotoides, Euplotopsis and Moneuplotes are not supported; the vannus-type group, which includes species without distinct morphological differences, seems to be undergoing incipient speciation and contains cryptic species; the hypervariable V4 region of the small subunit rDNA and D1-D2 region of the large subunit rDNA are the promising candidates for general species delimitation in Euplotes.
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Affiliation(s)
- Yan Zhao
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, People's Republic of China .,Laboratory of Protozoology, Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao 266003, People's Republic of China
| | - Zhenzhen Yi
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, School of Life Science, South China Normal University, Guangzhou 510631, People's Republic of China
| | - Alan Warren
- Department of Life Sciences, Natural History Museum, London SW7 5BD, UK
| | - Weibo Song
- Laboratory of Protozoology, Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao 266003, People's Republic of China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266003, People's Republic of China
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14
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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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Rajter Ľ, Vďačný P. Selection and paucity of phylogenetic signal challenge the utility of alpha-tubulin in reconstruction of evolutionary history of free-living litostomateans (Protista, Ciliophora). Mol Phylogenet Evol 2018; 127:534-544. [PMID: 29763665 DOI: 10.1016/j.ympev.2018.05.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 04/25/2018] [Accepted: 05/11/2018] [Indexed: 11/26/2022]
Abstract
The class Litostomatea represents a highly diverse but monophyletic group, uniting both free-living and endosymbiotic ciliates. Ribosomal RNA genes and ITS-region sequences helped to recognize and define the main litostomatean lineages, but did not provide enough phylogenetic signal to unambiguously resolve their interrelationships. In this study, we attempted to improve the resolution among main free-living predatory lineages by adding the gene coding for alpha-tubulin. However, our phylogenetic analyses challenged the performance of alpha-tubulin in reconstruction of evolutionary history of free-living litostomateans. We identified several mutually interconnected problems associated with the ciliate alpha-tubulin gene: the paucity of phylogenetic signal, molecular homoplasies and non-neutral evolution. Positive selection may generate molecular homoplasies (parallel evolution), while negative selection may cause a small number of changes and hence little phylogenetic informativness. Both problems were encountered in nucleotide and amino acid alpha-tubulin alignments, indicating an action of various selective pressures. Taking into account the involvement of alpha-tubulin in many essential biological processes, this protein could be so strongly affected by purifying selection that it even might have become an inappropriate molecular marker for reconstruction of phylogenetic relationships. Therefore, a great caution should be paid when tubulin genes are included in phylogenetic and/or phylogenomic analyses.
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Affiliation(s)
- Ľubomír Rajter
- Department of Zoology, Comenius University in Bratislava, 842 15 Bratislava, Slovak Republic
| | - Peter Vďačný
- Department of Zoology, Comenius University in Bratislava, 842 15 Bratislava, Slovak Republic.
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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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Lian C, Luo X, Fan X, Huang J, Yu Y, Bourland W, Song W. Morphological and Molecular Redefinition of Euplotes platystoma Dragesco & Dragesco-Kernéis, 1986 and Aspidisca lynceus (Müller,1773) Ehrenberg, 1859, with Reconsideration of a "Well-known" Euplotes Ciliate, Euplotes harpa Stein, 1859 (Ciliophora, Euplotida). J Eukaryot Microbiol 2018; 65:531-543. [PMID: 29315959 DOI: 10.1111/jeu.12499] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 11/29/2017] [Accepted: 12/27/2017] [Indexed: 11/26/2022]
Abstract
We documented the morphology, infraciliature, silverline system, and molecular data of two euplotid species isolated from China, including two populations of the poorly known Euplotes platystoma Dragesco & Dragesco-Kernéis, and the previously well described Aspidisca lynceus (Müller, ) Ehrenberg, 1830. Based on the information available, an improved diagnosis of Euplotes platystoma is given, including: a narrow adoral zone with 44-68 membranelles, 10 frontoventral, 5 transverse, 2 left marginal and 2 caudal cirri, 11-13 dorsal kineties with 17-25 dikinetids in the mid-dorsal row, and dorsal silverline system of the double-eurystomus type. The Chinese population of Aspidisca lynceus closely resembles previously described populations. Phylogenetic analyses inferred from SSU rDNA sequences show that E. platystoma is closely related with E. neapolitanus, and the internal position of A. lynceus within this genus is still not robust. A reconsideration of the "well-known" Euplotes harpa and a comparison of all SSU rDNA sequences of E. harpa in GenBank are provided. We speculate that the sequences available from GenBank under the name of E. harpa are very likely from misidentified materials, that is, the identity of the species currently associated with the SSU rDNA of this "well-known" form in molecular databases requires further confirmation.
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Affiliation(s)
- Chunyu Lian
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, 266003, China.,Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Xiaotian Luo
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, 266003, China.,Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China.,Department of Biological Sciences, Boise State University, Boise, 83725, ID, USA
| | - Xinpeng Fan
- School of Life Sciences, East China Normal University, Shanghai, 200062, China
| | - Jie Huang
- Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Yuhe Yu
- Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - William Bourland
- Department of Biological Sciences, Boise State University, Boise, 83725, ID, USA
| | - Weibo Song
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, 266003, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China
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Kollmar M, Mühlhausen S. Nuclear codon reassignments in the genomics era and mechanisms behind their evolution. Bioessays 2017; 39. [PMID: 28318058 DOI: 10.1002/bies.201600221] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The canonical genetic code ubiquitously translates nucleotide into peptide sequence with several alterations known in viruses, bacteria, mitochondria, plastids, and single-celled eukaryotes. A new hypothesis to explain genetic code changes, termed tRNA loss driven codon reassignment, has been proposed recently when the polyphyly of the yeast codon reassignment events has been uncovered. According to this hypothesis, the driving force for genetic code changes are tRNA or translation termination factor loss-of-function mutations or loss-of-gene events. The free codon can subsequently be captured by all tRNAs that have an appropriately mutated anticodon and are efficiently charged. Thus, codon capture most likely happens by near-cognate tRNAs and tRNAs whose anticodons are not part of the recognition sites of the respective aminoacyl-tRNA-synthetases. This hypothesis comprehensively explains the CTG codon translation as alanine in Pachysolen yeast together with the long known translation of the same codon as serine in Candida albicans and related species, and can also be applied to most other known reassignments.
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Affiliation(s)
- Martin Kollmar
- Group Systems Biology of Motor Proteins, Department of NMR-Based Structural Biology, Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany
| | - Stefanie Mühlhausen
- Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, Bath, UK
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19
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Balzano S, Percopo I, Siano R, Gourvil P, Chanoine M, Marie D, Vaulot D, Sarno D. Morphological and genetic diversity of Beaufort Sea diatoms with high contributions from the Chaetoceros neogracilis species complex. JOURNAL OF PHYCOLOGY 2017; 53:161-187. [PMID: 27809344 DOI: 10.1111/jpy.12489] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 07/19/2016] [Indexed: 06/06/2023]
Abstract
Seventy-five diatom strains isolated from the Beaufort Sea (Canadian Arctic) in the summer of 2009 were characterized by light and electron microscopy (SEM and TEM), as well as 18S and 28S rRNA gene sequencing. These strains group into 20 genotypes and 17 morphotypes and are affiliated with the genera Arcocellulus, Attheya, Chaetoceros, Cylindrotheca, Eucampia, Nitzschia, Porosira, Pseudo-nitzschia, Shionodiscus, Thalassiosira, and Synedropsis. Most of the species have a distribution confined to the northern/polar area. Chaetoceros neogracilis and Chaetoceros gelidus were the most represented taxa. Strains of C. neogracilis were morphologically similar and shared identical 18S rRNA gene sequences, but belonged to four distinct genetic clades based on 28S rRNA, ITS-1 and ITS-2 phylogenies. Secondary structure prediction revealed that these four clades differ in hemi-compensatory base changes (HCBCs) in paired positions of the ITS-2, suggesting their inability to interbreed. Reproductively isolated C. neogracilis genotypes can thus co-occur in summer phytoplankton communities in the Beaufort Sea. C. neogracilis generally occurred as single cells but also formed short colonies. It is phylogenetically distinct from an Antarctic species, erroneously identified in some previous studies as C. neogracilis, but named here as Chaetoceros sp. This work provides taxonomically validated sequences for 20 Arctic diatom taxa, which will facilitate future metabarcoding studies on phytoplankton in this region.
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Affiliation(s)
- Sergio Balzano
- CNRS, UMR7144, Station Biologique De Roscoff, Sorbonne Universités, UPMC Univ Paris 06, 29680, Roscoff, France
| | - Isabella Percopo
- Integrative Marine Ecology Department, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121, Naples, Italy
| | | | - Priscillia Gourvil
- CNRS, UMR7144, Station Biologique De Roscoff, Sorbonne Universités, UPMC Univ Paris 06, 29680, Roscoff, France
| | - Mélanie Chanoine
- CNRS, UMR7144, Station Biologique De Roscoff, Sorbonne Universités, UPMC Univ Paris 06, 29680, Roscoff, France
| | - Dominique Marie
- CNRS, UMR7144, Station Biologique De Roscoff, Sorbonne Universités, UPMC Univ Paris 06, 29680, Roscoff, France
| | - Daniel Vaulot
- CNRS, UMR7144, Station Biologique De Roscoff, Sorbonne Universités, UPMC Univ Paris 06, 29680, Roscoff, France
| | - Diana Sarno
- Integrative Marine Ecology Department, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121, Naples, Italy
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Syberg-Olsen MJ, Irwin NAT, Vannini C, Erra F, Di Giuseppe G, Boscaro V, Keeling PJ. Biogeography and Character Evolution of the Ciliate Genus Euplotes (Spirotrichea, Euplotia), with Description of Euplotes curdsi sp. nov. PLoS One 2016; 11:e0165442. [PMID: 27828996 PMCID: PMC5102374 DOI: 10.1371/journal.pone.0165442] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2016] [Accepted: 10/06/2016] [Indexed: 01/08/2023] Open
Abstract
Ciliates comprise a diverse and ecologically important phylum of unicellular protists. One of the most specious and best-defined genera is Euplotes, which constitutes more than 70 morphospecies, many of which have never been molecularly tested. The increasing number of described Euplotes taxa emphasizes the importance for detailed characterizations of new ones, requiring standardized morphological observations, sequencing of molecular markers and careful comparison with previous literature. Here we describe Euplotes curdsi sp. nov., distinguishable by the combination of the following features: 45–65 μm length, oval or elongated shape with both ends rounded, narrow peristome with 25–34 adoral membranelles, conspicuous paroral membrane, double-eurystomus dorsal argyrome type, 6–7 dorsolateral kineties and 10 frontoventral cirri. Three populations of the novel species have been found in brackish and marine samples in the Mediterranean and the White Sea. We provide the SSU rRNA gene sequences of these populations, and an updated phylogeny of the genus Euplotes. Using the molecular phylogenetic tree, we inferred aspects of the biogeographical history of the genus and the evolution of its most important taxonomic characters in order to provide a frame for future descriptions. Ultimately, these data reveal recurrent trends of freshwater invasion and highlight the dynamic, yet convergent, morphological evolution of Euplotes.
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Affiliation(s)
- Mitchell J. Syberg-Olsen
- Canadian Institute for Advanced Research, Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada
| | - Nicholas A. T. Irwin
- Canadian Institute for Advanced Research, Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada
| | | | - Fabrizio Erra
- Dipartimento di Biologia, Università di Pisa, Pisa, Italy
| | | | - Vittorio Boscaro
- Canadian Institute for Advanced Research, Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada
- * E-mail:
| | - Patrick J. Keeling
- Canadian Institute for Advanced Research, Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada
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Pedrini B, Suter-Stahel T, Vallesi A, Alimenti C, Luporini P. Molecular Structures and Coding Genes of the Water-Borne Protein Pheromones of Euplotes petzi, an Early Diverging Polar Species of Euplotes. J Eukaryot Microbiol 2016; 64:164-172. [PMID: 27455370 DOI: 10.1111/jeu.12348] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 06/27/2016] [Accepted: 07/19/2016] [Indexed: 12/01/2022]
Abstract
Euplotes is diversified into dozens of widely distributed species that produce structurally homologous families of water-borne protein pheromones governing self-/nonself-recognition phenomena. Structures of pheromones and pheromone coding genes have so far been studied from species lying in different positions of the Euplotes phylogenetic tree. We have now cloned the coding genes and determined the NMR molecular structure of four pheromones isolated from Euplotes petzi, a polar species which is phylogenetically distant from previously studied species and forms the deepest branching clade in the tree. The E. petzi pheromone genes have significantly shorter sequences than in other congeners, lack introns, and encode products of only 32 amino acids. Likewise, the three-dimensional structure of the E. petzi pheromones is markedly simpler than the three-helix up-down-up architecture previously determined in another polar species, Euplotes nobilii, and in a temperate-water species, Euplotes raikovi. Although sharing the same up-down-up architecture, it includes only two short α-helices that find their topological counterparts with the second and third helices of the E. raikovi and E. nobilii pheromones. The overall picture that emerges is that the evolution of Euplotes pheromones involves progressive increases in the gene sequence length and in the complexity of the three-dimensional molecular structure.
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Affiliation(s)
- Bill Pedrini
- Paul Scherrer Institute, Villigen 5232, Switzerland
| | - Thea Suter-Stahel
- Institute of Molecular Biology and Biophysics, ETH Zürich, Zürich 8093, Switzerland
| | - Adriana Vallesi
- Laboratory of Eukaryotic Microbiology and Animal Biology, School of Biosciences and Veterinary Medicine, University of Camerino, Camerino (MC) 62032, Italy
| | - Claudio Alimenti
- Laboratory of Eukaryotic Microbiology and Animal Biology, School of Biosciences and Veterinary Medicine, University of Camerino, Camerino (MC) 62032, Italy
| | - Pierangelo Luporini
- Laboratory of Eukaryotic Microbiology and Animal Biology, School of Biosciences and Veterinary Medicine, University of Camerino, Camerino (MC) 62032, Italy
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Luporini P, Pedrini B, Alimenti C, Vallesi A. Revisiting fifty years of research on pheromone signaling in ciliates. Eur J Protistol 2016; 55:26-38. [PMID: 27345662 DOI: 10.1016/j.ejop.2016.04.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Revised: 04/22/2016] [Accepted: 04/25/2016] [Indexed: 01/15/2023]
Abstract
Among protists, pheromones have been identified in a great variety of algal species for their activity in driving gamete-gamete interactions for fertilization. Analogously in ciliates, pheromones have been identified for their activity in inducing the sexual phenomenon of conjugation. Although this identification was pioneered by Kimball more than fifty years ago, an effective isolation and chemical characterization of ciliate pheromones has remained confined to species of Blepharisma, Dileptus and Euplotes. In Euplotes species, in which the molecular structures have been determined, pheromones form species-specific families of structurally homologous helical, cysteine-rich, highly-stable proteins. Being structurally homologous, they can bind cells in competition with one another, raising interesting functional analogies with the families of growth factors and cytokines that regulate cell differentiation and development in higher organisms. In addition to inducing conjugation by binding cells in heterologous fashion, Euplotes pheromones act also as autocrine growth factors by binding to, and promoting the vegetative reproduction of the same cells from which they originate. This autocrine activity is most likely primary, providing a concrete example of how the original function of a molecule can be obscured during evolution by the acquisition of a new one.
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Affiliation(s)
- Pierangelo Luporini
- Laboratory of Eukaryotic Microbiology and Animal Biology, School of Biosciences and Veterinary Medicine, University of Camerino, 62032 Camerino, MC, Italy.
| | - Bill Pedrini
- Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Claudio Alimenti
- Laboratory of Eukaryotic Microbiology and Animal Biology, School of Biosciences and Veterinary Medicine, University of Camerino, 62032 Camerino, MC, Italy
| | - Adriana Vallesi
- Laboratory of Eukaryotic Microbiology and Animal Biology, School of Biosciences and Veterinary Medicine, University of Camerino, 62032 Camerino, MC, Italy
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Fotedar R, Stoeck T, Filker S, Fell JW, Agatha S, Al Marri M, Jiang J. Description of the Halophile Euplotes qatarensis nov. spec. (Ciliophora, Spirotrichea, Euplotida) Isolated from the Hypersaline Khor Al-Adaid Lagoon in Qatar. J Eukaryot Microbiol 2016; 63:578-90. [PMID: 26864150 DOI: 10.1111/jeu.12305] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Revised: 01/21/2016] [Accepted: 02/02/2016] [Indexed: 11/30/2022]
Abstract
The morphology, ontogenesis, and phylogenetic relationships of a halophile euplotid ciliates, Euplotes qatarensis nov. spec., isolated from the Khor Al-Adaid Lagoon in Qatar were investigated based on live observation as well as protargol- and silver nitrate-impregnated methods. The new species is characterised by a combination of features: the halophile habitat, a cell size of 50-65 × 33-40 μm, seven dorsal ridges, 10 commonly sized frontoventral cirri, two widely spaced marginal cirri, 10 dorsolateral kineties, and a double silverline pattern. The morphogenesis is similar to that of its congeners: (i) the oral primordium develops hypoapokinetally and the parental oral apparatus is retained; (ii) the frontoventral-transverse field of five streaks gives rise to the frontal, ventral, and transverse cirri, but not to the cirri I/1 and the marginal cirri; (iii) the dorsal somatic ciliature develops by intrakinetal proliferation of basal bodies in two anlagen per kinety that are just anterior and posterior to the future division furrow; (iv) the caudal cirri are formed by the two rightmost dorsolateral kineties. The SSU rDNA sequence of E. qatarensis branches with full support in the Euplotopsis elegans-Euplotes nobilii-Euplotopsis raikovi clade. The closest related publicly available SSU rDNA sequence is the one of E. nobilii, with which E. qatarensis has 93.4% sequence similarity. Euplotes parawoodruffi Song & Bradbury, 1997 is transferred to the genus Euplotoides based on the absence of frontoventral cirrus VI/3.
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Affiliation(s)
- Rashmi Fotedar
- Department of Genetic Engineering, Biotechnology Centre, Ministry of Environment, 7634 Doha, Qatar
| | - Thorsten Stoeck
- Department of Ecology, University of Kaiserslautern, D-67633, Kaiserslautern, Germany
| | - Sabine Filker
- Department of Ecology, University of Kaiserslautern, D-67633, Kaiserslautern, Germany
| | - Jack W Fell
- Rosenstiel School of Marine and Atmospheric Science, University of Miami, Key Biscayne, FL, 33149, USA
| | - Sabine Agatha
- Department of Ecology and Evolution, University of Salzburg, Hellbrunnerstrasse 34, A-5020, Salzburg, Austria
| | - Masoud Al Marri
- Department of Genetic Engineering, Biotechnology Centre, Ministry of Environment, 7634 Doha, Qatar
| | - Jiamei Jiang
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Education, 201306, Shanghai, China
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