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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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Abraham JS, Somasundaram S, Maurya S, Gupta R, Makhija S, Toteja R. Characterization of Euplotes lynni nov. spec., E. indica nov. spec. and description of E. aediculatus and E. woodruffi (Ciliophora, Euplotidae) using an integrative approach. Eur J Protistol 2021; 79:125779. [PMID: 33706203 DOI: 10.1016/j.ejop.2021.125779] [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: 02/14/2020] [Revised: 01/14/2021] [Accepted: 01/23/2021] [Indexed: 11/26/2022]
Abstract
Four species belonging to the genus Euplotes have been investigated, namely: E. lynni nov. spec., E. indica nov. spec., E. aediculatus, and E. woodruffi. All populations are from India and were investigated using morphological and molecular markers. The phylogenetic relationships were inferred from small subunit ribosomal rRNA gene (SSU rRNA), internal transcribed spacer (ITS) region, and mitochondrial cytochrome c oxidase subunit I (COI) gene. Predicted secondary structure models for two new species using the hypervariable region of the SSU rRNA gene and ITS2 region support the distinctness of both species. Morphological characters were subjected to principal component analysis (PCA) and genetic variations were studied in-depth to analyze the relatedness of the two new species with their congeners. An integrative approach combining morphological features, molecular analysis, and ecological characteristics was carried out to understand the phylogenetic position of the reported species within the different clades of the genus Euplotes.
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Affiliation(s)
- Jeeva Susan Abraham
- Ciliate Biology Laboratory, Acharya Narendra Dev College, University of Delhi, Govindpuri, Kalkaji, New Delhi 110019, India
| | - Sripoorna Somasundaram
- Ciliate Biology Laboratory, Acharya Narendra Dev College, University of Delhi, Govindpuri, Kalkaji, New Delhi 110019, India
| | - Swati Maurya
- Ciliate Biology Laboratory, Acharya Narendra Dev College, University of Delhi, Govindpuri, Kalkaji, New Delhi 110019, India
| | - Renu Gupta
- Maitreyi College, University of Delhi, Bapu Dham, Chanakyapuri, New Delhi 110021, India.
| | - Seema Makhija
- Ciliate Biology Laboratory, Acharya Narendra Dev College, University of Delhi, Govindpuri, Kalkaji, New Delhi 110019, India
| | - Ravi Toteja
- Ciliate Biology Laboratory, Acharya Narendra Dev College, University of Delhi, Govindpuri, Kalkaji, New Delhi 110019, India.
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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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Conjugation in Euplotes raikovi (Protista, Ciliophora): New Insights into Nuclear Events and Macronuclear Development from Micronucleate and Amicronucleate Cells. Microorganisms 2020; 8:microorganisms8020162. [PMID: 31979289 PMCID: PMC7074782 DOI: 10.3390/microorganisms8020162] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 01/16/2020] [Accepted: 01/20/2020] [Indexed: 01/08/2023] Open
Abstract
Ciliates form a distinct group of single-celled eukaryotes that host two types of nuclei (micro and macronucleus) in the same cytoplasm and have a special sexual process known as conjugation, which involves mitosis, meiosis, fertilization, nuclear differentiation, and development. Due to their high species diversity, ciliates have evolved different patterns of nuclear events during conjugation. In the present study, we investigate these events in detail in the marine species Euplotes raikovi. Our results indicate that: (i) conjugation lasts for about 50 h, the longest stage being the development of the new macronucleus (ca. 36 h); (ii) there are three prezygotic micronuclear divisions (mitosis and meiosis I and II) and two postzygotic synkaryon divisions; and (iii) a fragment of the parental macronucleus fuses with the new developing macronucleus. In addition, we describe for the first time conjugation in amicronucleate E. raikovi cells. When two amicronucleate cells mate, they separate after about 4 h without evident nuclear changes; when one amicronucleate cell mates with a micronucleate cell, the micronucleus undergoes regular prezygotic divisions to form migratory and stationary pronuclei, but the two pronuclei fuse in the same cell. In the amicronucleate cell, the parental macronucleus breaks into fragments, which are then recovered to form a new functional macronucleus. These results add new information on the process of conjugation in both micronucleate and amicronucleate Euplotes cells.
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Affiliation(s)
- Jim D. Clark
- T. H. Morgan School of Biological Sciences, University of Kentucky, Lexington, KY 40506
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Ricci F, Candelori A, Brandi A, Alimenti C, Luporini P, Vallesi A. The Sub-Chromosomic Macronuclear Pheromone Genes of the Ciliate Euplotes raikovi: Comparative Structural Analysis and Insights into the Mechanism of Expression. J Eukaryot Microbiol 2018; 66:376-384. [PMID: 30076754 DOI: 10.1111/jeu.12677] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 07/16/2018] [Accepted: 07/25/2018] [Indexed: 12/23/2022]
Abstract
In Euplotes raikovi, we have determined the full-length sequences of a family of macronuclear genes that are the transcriptionally active versions of codominant alleles inherited at the mating-type (mat) locus of the micronuclear genome, and encode cell type-distinctive signaling pheromones. These genes include a 225-231-bp coding region flanked by a conserved 544-bp 5'-leader region and a more variable 3'-trailer region. Two transcription initiation start sites and two polyadenylation sites associated with nonconventional signals cooperate with a splicing phenomenon of a 326-bp intron residing in the 5'-leader region in the generation of multiple transcripts from the same gene. In two of them, the synthesis of functional products depends on the reassignment to a sense codon, or readthrough of a strictly conserved leaky UAG stop codon. That this reassignment may take place is suggested by the position this codon occupies in the transcripts, close to the transcript extremity and far from the poly(A) tail. In such a case, one product is a 69-amino acid protein in search of function and the second product is a 126-amino acid protein that represents a membrane-bound pheromone isoform candidate to function as a cell type-specific binding site (receptor) of the soluble pheromones.
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Affiliation(s)
- Francesca Ricci
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino (MC), 62032, Italy
| | - Annalisa Candelori
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino (MC), 62032, Italy
| | - Anna Brandi
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino (MC), 62032, Italy
| | - Claudio Alimenti
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino (MC), 62032, Italy
| | - Pierangelo Luporini
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino (MC), 62032, Italy
| | - Adriana Vallesi
- 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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8
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Luporini P, Alimenti C, Vallesi A. Ciliate pheromone structures and activity: a review. ACTA ACUST UNITED AC 2014. [DOI: 10.1080/11250003.2014.976282] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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9
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Vallesi A, Alimenti C, Federici S, Di Giuseppe G, Dini F, Guella G, Luporini P. Evidence for gene duplication and allelic codominance (not hierarchical dominance) at the mating-type locus of the ciliate, Euplotes crassus. J Eukaryot Microbiol 2014; 61:620-9. [PMID: 25040318 DOI: 10.1111/jeu.12140] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Revised: 03/25/2014] [Accepted: 05/03/2014] [Indexed: 11/30/2022]
Abstract
The high-multiple mating system of Euplotes crassus is known to be controlled by multiple alleles segregating at a single locus and manifesting relationships of hierarchical dominance, so that heterozygous cells would produce a single mating-type substance (pheromone). In strain L-2D, now known to be homozygous at the mating-type locus, we previously identified two pheromones (Ec-α and Ec-1) characterized by significant variations in their amino acid sequences and structure of their macronuclear coding genes. In this study, pheromones and macronuclear coding genes have been analyzed in strain POR-73 characterized by a heterozygous genotype and strong mating compatibility with L-2D strain. It was found that POR-73 cells contain three distinct pheromone coding genes and, accordingly, secrete three distinct pheromones. One pheromone revealed structural identity in amino acid sequence and macronuclear coding gene to the Ec-α pheromone of L-2D cells. The other two pheromones were shown to be new and were designated Ec-2 and Ec-3 to denote their structural homology with the Ec-1 pheromone of L-2D cells. We interpreted these results as evidence of a phenomenon of gene duplication at the E. crassus mating-type locus, and lack of hierarchical dominance in the expression of the macronuclear pheromone genes in cells with heterozygous genotypes.
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Affiliation(s)
- Adriana Vallesi
- Laboratory of Eukaryotic Microbiology and Animal Biology, University of Camerino, 62032, Camerino, MC, Italy
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10
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Alimenti C, Vallesi A, Federici S, di Giuseppe G, Fernando D, Carratore V, Luporini P. Isolation and structural characterization of two water-borne pheromones from Euplotes crassus, a ciliate commonly known to carry membrane-bound pheromones. J Eukaryot Microbiol 2011; 58:234-41. [PMID: 21414056 DOI: 10.1111/j.1550-7408.2011.00535.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ciliates comprise species synthesizing water-diffusible mating type factors or pheromones and species synthesizing insoluble, cell membrane-bound pheromones. Euplotes crassus has traditionally been placed in the latter group. In contrast with this notion, we found that E. crassus is a constitutive pheromone-secreting ciliate, like other Euplotes species. From cell-free filtrate preparations of the E. crassus strain L-2D, we isolated two distinct pheromones, designated as Ec-α and Ec-1, and determined their complete amino acid sequences by combined chemical and genetic approaches. The Ec-α pheromone sequence extends for 56 amino acid residues with six cysteines and shows a molecular mass of 6,183 Da, while the Ec-1 pheromone sequence extends for 45 amino acid residues with 10 cysteines and shows a molecular mass of 4,840 Da. Marked structural differences distinguish the full-length Ec-α and Ec-1 coding sequences, which have been cloned and characterized from the transcriptionally active macronuclear genome. They were taken as clear indication that the Ec-α and Ec-1 pheromones are specified by genes that are not allelic, but likely derived from a duplicated genetic locus of the transcriptionally silent micronuclear genome.
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Affiliation(s)
- Claudio Alimenti
- Dipartimento di Scienze Ambientali e Naturali, University of Camerino, 62032 Camerino (MC), Italy
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Di GG, Miceli C, Zahn R, Damberger F, Wüthrich K, Luporini P. A structurally deviant member of the Euplotes raikovi pheromone family: Er-23. J Eukaryot Microbiol 2002; 49:86-92. [PMID: 11908903 DOI: 10.1111/j.1550-7408.2002.tb00347.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Pheromones of Euplotes raikovi form a homologous family of proteins with 37- to 40-amino acid residues, including six cysteines that form three strictly conserved disulfide bridges. The determination of the primary structure of the pheromone Er-23, which was isolated from cells derived from natural populations of E. raikovi that secrete the other known pheromones, has now revealed a novel structure type. The polypeptide chain of this pheromone contains 51 residues, 10 of which are cysteines presumably involved in the formation of five disulfide bridges, and lacks a carboxyl-terminal tail following the last cysteine of the sequence. The elongation of the Er-23 molecule is presumed to result from multiple events of gene duplication starting from an ancestral motif Xxx(2-4)-Cys-Xxx(5-7)-Cys.
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Affiliation(s)
- Giuseppe Graziano Di
- Dipartimento di Biologia Molecolare Cellulare Animale, University of Camerino, Italy
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12
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Bender J, Kämpfer M, Klein A. Faithful expression of a heterologous gene carried on an artificial macronuclear chromosome in Euplotes crassus. Nucleic Acids Res 1999; 27:3168-72. [PMID: 10454614 PMCID: PMC148544 DOI: 10.1093/nar/27.15.3168] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Macronuclear chromosomes of hypotrichous ciliates are gene-sized molecules carrying the coding sequence flanked by short non-translated regions and bounded by telomeres. We have constructed artificial chromosomes for investigation of transcription in the macronucleus of Euplotes crassus. The neo gene was put under the control of the 5"-non-translated region of the TBP gene of E.crassus. These molecules were introduced into the cell with the help of liposomes. The cells were transformed and survived high concentrations of geneticin. The artificial chromosomes were kept in the macro-nucleus for at least 50 days at a copy number of about 200 per macronucleus. Expression of the gene was shown by reverse transcription of the neo messenger. The transcription start was mapped and found to coincide with that found on the natural macronuclear chromosome encoding TBP in E.crassus.
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Affiliation(s)
- J Bender
- Genetics, Department of Biology, University of Marburg, D-35032 Marburg, Germany
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13
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Brünen-Nieweier C, Christoph Weiligmann J, Hansen B, Kuhlmann HW, Möllenbeck M, Heckmann K. The pheromones and pheromone genes of new stocks of the Euplotes octocarinatus species complex. Eur J Protistol 1998. [DOI: 10.1016/s0932-4739(98)80022-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Abstract
It is widely believed that the number of species of micro-organisms in the world is extremely large. Here, we offer the contrasting view--that the number may be quite modest. Most of the work reviewed refers to the ciliated protozoa. As with all microbial groups, we must define our concept of "species", and for ciliates, the "morphospecies" concept appears to be at least as robust as any other. Critical examination of published descriptions of ciliates provides a "best estimate" of 3744 for the global number of free-living morphospecies. Of these, 793 are associated with marine sediments, and 1370 with freshwater sediments. In an independent analysis based on extrapolation (assuming the ubiquity of species) from ecological datasets, we estimate the numbers of species in marine and freshwater sediments as 597 and 732, respectively (i.e. within a factor of two of the figures obtained from taxonomic analysis). This apparent convergence of independent estimates will strengthen if, as is likely, the number of nominal species is further reduced by taxonomic revision. These relatively low numbers of species are consistent with (a) the vast amount of published information indicating typically cosmopolitan distributions for ciliates and other microbes, and (b) recent experimental evidence that most free-living ciliates are rare or cryptic--seldom detectable, but present, and "waiting" for suitable conditions to arrive. In summary, most ciliates (and other micro-organisms) are probably ubiquitous, endemics are rare, global species richness is relatively low, and, at least in the case of the ciliates, most species have already been discovered.
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Affiliation(s)
- B J Finlay
- Institute of Freshwater Ecology, Ambleside, Cumbria, UK.
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15
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Nanney DL, Park C, Preparata R, Simon EM. Comparison of sequence differences in a variable 23S rRNA domain among sets of cryptic species of ciliated protozoa. J Eukaryot Microbiol 1998; 45:91-100. [PMID: 9495037 DOI: 10.1111/j.1550-7408.1998.tb05075.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Studies were undertaken to discover the relative molecular distances separating some familiar forms of ciliated protozoa, and the genetic species they include. Sequences of 190 bases of the D2 domain of the large ribosomal nucleic acid molecule were obtained by polymerase chain reaction from protists of three distinctive groups of ciliated protozoa-Colpoda, Paramecium and Tetrahymena. Evolutionary trees were constructed for each set of sequences using the PHYLOGEN 1.0 string programs. All three groups of ciliates manifested large molecular diversity among strains difficult or impossible to distinguish morphologically. The largest single evolutionary distance within a group was the 75 differences separating Tetrahymena paravorax from the other tetrahymenids. The largest mean distance for a group was the 21.2 for the colpodids. In all the protist groups the large molecular diversity is obscured by morphological conservatism associated with constraints of ancient designs. The molecular diversity within morphotypes argues for long evolutionary coexistence of species differentiated from each other in significant physiological, ecological, or nutritional ways.
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Affiliation(s)
- D L Nanney
- Department of Ecology, Ethology and Evolution, University of Illinois, Urbana 61801, USA
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STOCK CHRISTIAN, KRÜPPEL THOMAS, LUEKEN WOLFGANG. Kinesis in Euplotes vannus-Ethological and Electrophysiological Characteristics of Chemosensory Behavior. J Eukaryot Microbiol 1997. [DOI: 10.1111/j.1550-7408.1997.tb05719.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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17
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Ricci N, Luverà G, Cacciatori M, Banchetti R, Lueken W. The effects of 2 μM Hg++ on the ethogram of Euplotes vannus (Ciliata, Hypotrichida). Eur J Protistol 1997. [DOI: 10.1016/s0932-4739(97)80021-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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18
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Dönhoff T, Klein A. Timing of differential amplification of macronucleus-destined sequences during macronuclear development in the hypotrichous ciliate Euplotes crassus. Chromosoma 1996; 105:172-9. [PMID: 8781185 DOI: 10.1007/bf02509498] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The change in copy numbers of macronucleus-destined gene sequences was followed in anlagen DNA during postconjugational development in Euplotes crassus. As noted earlier, copy numbers increase during the polytene stage. During this replication process major differential amplification of different genes is not observed. Instead it is only achieved during or shortly after the fragmentation of the polytene chromosomes. This process is not totally synchronous with respect to different genes. Highly amplified genes are excised earlier than genes with a low final macronuclear copy number. Unexpectedly, the pattern of processing of the newly added oversized telomeres also appears to correlate with the degree of gene amplification. These observations are discussed in terms of a limited replication period after polytene chromosome fragmentation leading to preferential amplification of early excised genes.
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Affiliation(s)
- T Dönhoff
- Molecular Genetics, Department of Biology, Philipps University, D-35032 Marburg, Germany
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Bergemann J, Florian V, Kremser T, Klein A. Two different macronuclear EF-1 alpha-encoding genes of the ciliate Euplotes crassus are very dissimilar in their sequences, copy numbers and transcriptional activities. Gene X 1996; 168:109-12. [PMID: 8626055 DOI: 10.1016/0378-1119(95)00728-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Genes (EFA) encoding the translation elongation factor EF-1 alpha (EFA) or the prokaryotic homolog EFTu frequently occur in multiple copies in the same organism. This has been interpreted either in terms of a potential of differential gene expression during different phases of development, or as gene dosage adaptation to the need of high-level production of the gene products. Since ciliates can differentially amplify their genes, the latter argument would lead to the expectation of only one EFA gene in the macronucleus. However, we have found two such genes which strongly differ in both copy number and codon usage. Both transcripts are detectable at very different levels. The expression of the genes takes place both in the vegetative and sexual phases, i.e.,during conjugation.
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Affiliation(s)
- J Bergemann
- Molecular Genetics, Department of Biology, Philipps-University, Marburg, Germany
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20
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Rhythmic spontaneous depolarizations determine a slow-and-fast rhythm in walking of the marine hypotrich Euplotes vannus. Eur J Protistol 1996. [DOI: 10.1016/s0932-4739(96)80038-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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21
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Luporini P, Miceli C, Ortenzi C, Vallesi A. Ciliate pheromones. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 1996; 17:80-104. [PMID: 8822801 DOI: 10.1007/978-3-642-80106-8_5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- P Luporini
- Dipartimento di Biologia Molecolare, Cellulare e Animale, Università di Camerino, Italy
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Brandt A, Klein A. Transcription rates and transcript stabilities of macronuclear genes in vegetative Euplotes crassus cells. J Eukaryot Microbiol 1995; 42:691-6. [PMID: 8520583 DOI: 10.1111/j.1550-7408.1995.tb01617.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
In hypotrichous ciliates such as Euplotes crassus genes in the transcriptionally active macronucleus are present on individual minichromosomes which occur in gene-specific copy numbers. This different degree of gene amplification can be understood as a means to preset the expression potential of the respective genetic information. In addition, the actual steady state transcript amounts are governed by the transcription rates and transcript stabilities. To establish the relative effects of these three parameters the copy numbers of genes transcribed by the three different polymerases were determined. The transcript levels of growing or starving vegetative cells were then determined, and nuclear run-on assays were performed to determine the transcription rates of the genes in the different nutritional states. A weak correlation between the gene copy numbers and transcription rates was found. The transcripts of genes synthesized by RNA polymerase II exhibited different stabilities upon starvation of the cells, compared to the supposedly stable ribosomal 5S and 26S RNA. Refeeding of the cells after starvation also resulted in a differential response with respect to the accumulation of the transcripts of different genes transcribed by RNA polymerase II, which can be interpreted in the context of the gene functions.
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MESH Headings
- Animals
- Base Sequence
- Biological Evolution
- Conjugation, Genetic
- Conserved Sequence
- DNA Probes
- DNA, Protozoan/genetics
- DNA, Ribosomal/genetics
- Euplotes/genetics
- Euplotes/physiology
- Gene Expression
- Genes, Protozoan
- RNA Polymerase II/metabolism
- RNA, Protozoan/biosynthesis
- RNA, Protozoan/genetics
- RNA, Ribosomal/biosynthesis
- RNA, Ribosomal/genetics
- RNA, Ribosomal, 5S/biosynthesis
- RNA, Ribosomal, 5S/genetics
- Transcription, Genetic
- Tubulin/biosynthesis
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Affiliation(s)
- A Brandt
- Department of Biology, Phillipps-University, Marburg, Germany
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Jones DE, Tu TD, Sweeney RW, Clark DP. Isolation of Cryptosporidium and bovine cDNA clones from a Cryptosporidium-infected MDBK cell line subtraction library. J Eukaryot Microbiol 1994; 41:46S-47S. [PMID: 7804246 DOI: 10.1111/j.1550-7408.1994.tb06040.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- D E Jones
- Dept. of Pathology and Lab. Med. Univ. of Pennsylvania, Philadelphia 19104
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Miceli C, Ballarini P, Di Giuseppe G, Valbonesi A, Luporini P. Identification of the tubulin gene family and sequence determination of one beta-tubulin gene in a cold-poikilotherm protozoan, the antarctic ciliate Euplotes focardii. J Eukaryot Microbiol 1994; 41:420-7. [PMID: 8087111 DOI: 10.1111/j.1550-7408.1994.tb06100.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Four different tubulin genes were identified in the somatic nucleus (macronucleus) of Euplotes focardii, a strictly cold-adapted, Antarctic ciliate: one of 1,800 bp for alpha-tubulin and three of 2,150, 1,900, and 1,600 bp, respectively, for beta-tubulin. Preliminarily analysed for restriction fragment length polymorphisms, these genes showed remarkable differences in organisation from tubulin genes of other ciliates which live in temperate areas and were analysed in parallel with E. focardii. The complete coding sequence of the 1,600 bp beta-tubulin gene was then determined and shown to contain unique structural features of potential importance for E. focardii microtubule organization and activity. Of eight unique substitutions detected, seven were concentrated in the large amino terminal domain of the molecule that directly interacts with the carboxy terminal region of alpha-tubulin for heterodimer formation. Sequence analysis of the cloned gene revealed, in addition, a potential new exception in the use of the genetic code by ciliates. A TAG codon was aligned in correspondence with Trp-21 which is strictly conserved in every tubulin sequence so far determined.
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Affiliation(s)
- C Miceli
- Dipartimento di Biologia Molecolare, Cellulare ed Animale Università di Camerino, Italy
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CAPRETTE CHRISTOPHERL, GATES MICHAELA. Quantitative Analyses of Interbreeding in Populations of vannus-Morphotype Euplotes, with Special Attention to the Nominal Species E. vannus and E. crassus. J Eukaryot Microbiol 1994. [DOI: 10.1111/j.1550-7408.1994.tb06084.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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