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Méndez-Sánchez D, Mayén-Estrada R, Hu X. Euplotes octocarinatus Carter, 1972 (Ciliophora, Spirotrichea, Euplotidae): Considerations on its morphology, phylogeny, and biogeography. Eur J Protistol 2020; 74:125667. [DOI: 10.1016/j.ejop.2019.125667] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 12/19/2019] [Accepted: 12/22/2019] [Indexed: 11/28/2022]
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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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Jiang Y, Zhang T, Vallesi A, Yang X, Gao F. Time-course analysis of nuclear events during conjugation in the marine ciliate Euplotes vannus and comparison with other ciliates (Protozoa, Ciliophora). Cell Cycle 2019; 18:288-298. [PMID: 30563432 DOI: 10.1080/15384101.2018.1558871] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Ciliates represent a morphologically and genetically distinct group of single-celled eukaryotes that segregate germline and somatic functions into two types of nuclei and exhibit complex cytogenetic events during the sexual process of conjugation, which is under the control of the so-called "mating type systems". Studying conjugation in ciliates may provide insight into our understanding of the origins and evolution of sex and fertilization. In the present work, we studied in detail the sexual process of conjugation using the model species Euplotes vannus, and compared these nuclear events with those occurring in other ciliates. Our results indicate that in E. vannus: 1) conjugation requires about 75 hours to complete: the longest step is the development of the new macronucleus (ca. 64h), followed by the nuclear division of meiosis I (5h); the mitotic divisions usually take only 2h; 2) there are three prezygotic divisions (mitosis and meiosis I and II), and two of the eight resulting nuclei become pronuclei; 3) after the exchange and fusion of the pronuclei, two postzygotic divisions occur; two of the four products differentiate into the new micronucleus and macronucleus, respectively, and the parental macronucleus degenerates completely; 4) comparison of the nuclear events during conjugation in different ciliates reveals that there are generally three prezygotic divisions while the number of postzygotic divisions is highly variable. These results can serve as reference to investigate the mating type system operating in this species and to analyze genes involved in the different steps of the sexual process.
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Affiliation(s)
- Yaohan Jiang
- a Institute of Evolution and Marine Biodiversity , Ocean University of China , Qingdao , China.,b Ministry of Education , Key Laboratory of Mariculture (Ocean University of China) , Qingdao , China
| | - Tengteng Zhang
- a Institute of Evolution and Marine Biodiversity , Ocean University of China , Qingdao , China.,b Ministry of Education , Key Laboratory of Mariculture (Ocean University of China) , Qingdao , China
| | - Adriana Vallesi
- c Laboratory of Eukaryotic Microbiology and Animal Biology , University of Camerino , Camerino , Italy
| | - Xianyu Yang
- d College of Animal Science and Technology , Zhejiang A&F University , Hangzhou , China
| | - Feng Gao
- a Institute of Evolution and Marine Biodiversity , Ocean University of China , Qingdao , China.,b Ministry of Education , Key Laboratory of Mariculture (Ocean University of China) , Qingdao , China
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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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Frankel J. Klaus Heckmann (1934-2012). J Eukaryot Microbiol 2013; 60:322-5. [DOI: 10.1111/jeu.12039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Joseph Frankel
- Department of Biology; University of Iowa; 129 East Jefferson Street Iowa City Iowa 52242
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Coding genes and molecular structures of the diffusible signalling proteins (pheromones) of the polar ciliate, Euplotes nobilii. Mar Genomics 2012. [DOI: 10.1016/j.margen.2012.03.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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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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Brosnahan ML, Kulis DM, Solow AR, Erdner DL, Percy L, Lewis J, Anderson DM. Outbreeding lethality between toxic Group I and nontoxic Group III Alexandrium tamarense spp. isolates: Predominance of heterotypic encystment and implications for mating interactions and biogeography. DEEP-SEA RESEARCH. PART II, TOPICAL STUDIES IN OCEANOGRAPHY 2010; 57:175-189. [PMID: 24882951 PMCID: PMC4038962 DOI: 10.1016/j.dsr2.2009.09.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
We report the zygotic encystment of geographically dispersed isolates in the dinoflagellate species complex Alexandrium tamarense, in particular, successful mating of toxic Group I and nontoxic Group III isolates. However, hypnozygotes produced in Group I/III co-cultures complete no more than three divisions after germinating. Previous reports have suggested a mate recognition mechanism whereby hypnozygotes produced in co-cultures could arise from either homotypic (inbred) or heterotypic (outbred) gamete pairs. To determine the extent to which each occurs, a nested PCR assay was developed to determine parentage of individual hypnozygotes. The vast majority of hypnozygotes from pairwise Group I/III co-cultures were outbred, so that inviability was a result of hybridization, not inbreeding. These findings support the assertion that complete speciation underlies the phylogenetic structure of the Alexandrium tamarense species complex. Additionally, the ribosomal DNA (rDNA) copy numbers of both hybrid and single ribotype hypnozygotes were reduced substantially from those of haploid motile cells. The destruction of rDNA loci may be crucial for the successful mating of genetically distant conjugants and appears integral to the process of encystment. The inviability of Group I/III hybrids is important for public health because the presence of hybrid cysts may indicate ongoing displacement of a nontoxic population by a toxic one (or vice versa). Hybrid inviability also suggests a bloom control strategy whereby persistent, toxic Group I blooms could be mitigated by introduction of nontoxic Group III cells. The potential for hybridization in nature was investigated by applying the nested PCR assay to hypnozygotes from Belfast Lough, Northern Ireland, a region where Group I and III populations co-occur. Two hybrid cysts were identified in 14 successful assays, demonstrating that Group I and III populations do interbreed in that region. However, an analysis of mating data collected over an 18-year period indicated a leaky pre-mating barrier between ribosomal species (including Groups I and III). Whether the observed selectivity inhibits hybridization in nature is dependent on its mechanism. If the point of selectivity is the induction of gametogenesis, dissimilar ribotypes could interbreed freely, promoting displacement in cases where hybridization is lethal. If instead, selectivity occurs during the adhesion of gamete pairs, it could enable stable coexistence of A. tamarense species. In either case, hybrid inviability may impose a significant obstacle to range expansion. The nested PCR assay developed here is a valuable tool for investigation of interspecies hybridization and its consequences for the global biogeography of these important organisms.
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Affiliation(s)
- Michael L. Brosnahan
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | - David M. Kulis
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | - Andrew R. Solow
- Marine Policy Center, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | - Deana L. Erdner
- Department of Marine Science, The University of Texas at Austin, Marine Science Institute, 750 Channel View Drive, Port Aransas, TX 78373-5015, USA
| | - Linda Percy
- School of Biosciences, University of Westminster, 115 New Cavendish Street, London W1W 6UW, UK
| | - Jane Lewis
- School of Biosciences, University of Westminster, 115 New Cavendish Street, London W1W 6UW, UK
| | - Donald M. Anderson
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
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Valbonesi A, Ortenzi C, Luporini P. Observations on the biology ofEuplotes charon(Hypotrichida, Ciliophora). ACTA ACUST UNITED AC 2009. [DOI: 10.1080/11250008709355569] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Alessandro Valbonesi
- a Dipartimento di Biologia Cellulare , Università di Camerino , Via Camerini 2, Camerino, 62032, Italy
| | - Claudio Ortenzi
- a Dipartimento di Biologia Cellulare , Università di Camerino , Via Camerini 2, Camerino, 62032, Italy
| | - Pierangelo Luporini
- a Dipartimento di Biologia Cellulare , Università di Camerino , Via Camerini 2, Camerino, 62032, Italy
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KOSAKA TOSHIKAZU. Methods for Inducing Selfing, Selfing and Its Role in the Life Cycle of Euplotes woodruffi syngen 3 (Ciliophora). ACTA ACUST UNITED AC 2007. [DOI: 10.1111/j.1550-7408.1990.tb01110.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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12
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KUSCH JÜRGEN, HECKMANN KLAUS. Gamone Production in Large-Scale Cultures ofEuplotes octocarinatus1. ACTA ACUST UNITED AC 2007. [DOI: 10.1111/j.1550-7408.1988.tb04102.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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13
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DINI FERNANDO, BRACCHI PAOLO, GIANNÍ ALESSANDRO. Mating Types inAspidiscasp. (Ciliophora, Hypotrichida): a Cluster of Cryptic Species. ACTA ACUST UNITED AC 2007. [DOI: 10.1111/j.1550-7408.1987.tb03165.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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14
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Petroni G, Dini F, Verni F, Rosati G. A molecular approach to the tangled intrageneric relationships underlying phylogeny in Euplotes (Ciliophora, Spirotrichea). Mol Phylogenet Evol 2002; 22:118-30. [PMID: 11796035 DOI: 10.1006/mpev.2001.1030] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The cosmopolitan genus Euplotes is remarkable among ciliates for its species richness. To understand the still tangled taxonomy and phylogenetic relationships within the genus, small subunit rRNA sequences of 11 morphologically defined species colonizing different habitats were determined. Euplotes 18S rRNA is unique among ciliates for its anomalous length and high evolutionary rate. Phylogenetic reconstruction pointed to a high divergence between this genus and the other Spirotrichea, together with a high variability within the genus. Some of the relationships within the Euplotes group were also resolved. Data from the literature, based on morphological features, habitat, and symbiotic relationships, have been compared with our results and are critically discussed. In many cases, the molecular phylogenetic analysis disagreed with species relatedness established on morphological and ecological grounds. The occurrence of a radiation phenomenon in the evolution of the genus is postulated.
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MESH Headings
- Animals
- Base Sequence
- DNA, Protozoan/genetics
- DNA, Ribosomal/genetics
- Environment
- Euplotes/classification
- Euplotes/genetics
- Euplotes/ultrastructure
- Evolution, Molecular
- Genetic Variation
- Microscopy, Electron, Scanning
- Molecular Sequence Data
- Nucleic Acid Conformation
- Phylogeny
- RNA, Protozoan/chemistry
- RNA, Protozoan/genetics
- RNA, Ribosomal, 18S/chemistry
- RNA, Ribosomal, 18S/genetics
- Sequence Homology, Nucleic Acid
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Affiliation(s)
- Giulio Petroni
- Dipartimento di Etologia, Ecologia, Evoluzione, Università di Pisa, via A., Volta 4-6, 56126 Pisa, Italy
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Möllenbeck M, Heckmann K. Identification and characterization of a pheromone 2 specific binding protein of Euplotes octocarinatus. Eur J Protistol 2002. [DOI: 10.1078/0932-4739-00804] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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16
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Sakaguchi M, Murakami H, Suzaki T. Involvement of a 40-kDa glycoprotein in food recognition, prey capture, and induction of phagocytosis in the protozoon Actinophrys sol. Protist 2001; 152:33-41. [PMID: 11401035 DOI: 10.1078/1434-4610-00041] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A 40-kDa glycoprotein (gp40) was identified as a Con A-binding adhesive substance of the heliozoon Actinophrys sol for immobilizing and ingesting prey flagellates. Isolation and partial characterization of gp40 showed that: 1) gp40 is a major Con A-binding protein of Actinophrys with a molecular weight of 40 kDa, and is stored in secretory granules called extrusomes; 2) gp40 was purified by Con A-affinity chromatography, and the N-terminal amino acid sequence was determined as H2N-KVLK-FEDDFDTFDLQ; 3) prey flagellates became adhered to gp40-immobilized agarose beads; 4) phagocytosis of Actinophrys was induced against gp40-immobilized agarose beads; and 5) solubilized gp40 induced exocytosis of extrusomes and cell fusion of heliozoons. These results indicate that gp40 is a multi-functional secretory protein of Actinophrys, which is required in correct targeting of the heliozoon to food organisms as well as in self-recognition.
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Affiliation(s)
- M Sakaguchi
- Department of Biology, Faculty of Science, Kobe University, Japan
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Ortenzi C, Alimenti C, Vallesi A, Di Pretoro B, Terza AL, Luporini P. The autocrine mitogenic loop of the ciliate Euplotes raikovi: the pheromone membrane-bound forms are the cell binding sites and potential signaling receptors of soluble pheromones. Mol Biol Cell 2000; 11:1445-55. [PMID: 10749941 PMCID: PMC14858 DOI: 10.1091/mbc.11.4.1445] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Homologous proteins, denoted pheromones, promote cell mitotic proliferation and mating pair formation in the ciliate Euplotes raikovi, according to whether they bind to cells in an autocrine- or paracrine-like manner. The primary transcripts of the genes encoding these proteins undergo alternate splicing, which generates at least two distinct mRNAs. One is specific for the soluble pheromone, the other for a pheromone isoform that remains anchored to the cell surface as a type II protein, whose extracellular C-terminal region is structurally equivalent to the secreted form. The 15-kDa membrane-bound isoform of pheromone Er-1, denoted Er-1mem and synthesized by the same E. raikovi cells that secrete Er-1, has been purified from cell membranes by affinity chromatography prepared with matrix-bound Er-1, and its extracellular and cytoplasmic regions have been expressed as recombinant proteins. Using the purified material and these recombinant proteins, it has been shown that Er-1mem has the property of binding pheromones competitively through its extracellular pheromone-like domain and associating reversibly and specifically with a guanine nucleotide-binding protein through its intracellular domain. It has been concluded that the membrane-bound pheromone isoforms of E. raikovi represent the cell effective pheromone binding sites and are functionally equipped for transducing the signal generated by this binding.
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Affiliation(s)
- C Ortenzi
- Dipartimento di Biologia Molecolare Cellulare Animale, University of Camerino, 62032 Camerino (MC), Italy
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18
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Mollenbeck M. Genetic relationship of 32 cell lines of the Euplotes octocarinatus species complex revealed by random amplified polymorphic DNA (RAPD) fingerprinting. Mol Ecol 1999. [DOI: 10.1046/j.1365-294x.1999.00774.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Characterization of two genes encoding a fifth so far unknown pheromone of Euplotes octocarinatus. Eur J Protistol 1999. [DOI: 10.1016/s0932-4739(99)80041-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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20
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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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21
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Kuhlmann HW, Brünen-Nieweler C, Heckmann K. Pheromones of the ciliateEuplotes octocarinatus not only induce conjugation but also function as chemoattractants. ACTA ACUST UNITED AC 1997. [DOI: 10.1002/(sici)1097-010x(19970101)277:1<38::aid-jez4>3.0.co;2-c] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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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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Abstract
For long, our knowledge of the biology of ciliate pheromones has long relied solely upon the study of the two structurally unrelated "gamones" identified in culture filtrates of a Blepharisma species. However, the characterization of a number of polypeptide pheromones secreted by Euplotes raikovi and E. octocarinatus has now established that structural relationships of homology usually link these molecules, which is consistent with the genetic basis of the mating type systems evolved by these species. In this context, our growing appreciation of the conserved and variable elements of the pheromone architecture should foster progress in the understanding of pheromone-receptor interactions and thus, provide important clues into pheromone mechanisms of action.
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Affiliation(s)
- P Luporini
- Dipartimento di Biologia Molecolare, Cellulare e Animale, University of Camerino, Italy
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ORTENZI OLAUDIO, LUPORINI PIERANGELO. Competition Among Homologous Polypeptide Pheromones of the Ciliate Euplotes raikovi for Binding to Each Other's Cell Receptors. J Eukaryot Microbiol 1995. [DOI: 10.1111/j.1550-7408.1995.tb01573.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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26
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PLÜMPER EVELYN, FREIBURG MANFRED, HECKMANN KLAUS. Inhibition of Pair Formation by Concanavalin A and Concanavalin A-Binding Glycoconjugates in Euplotes octocarinatus. J Eukaryot Microbiol 1995. [DOI: 10.1111/j.1550-7408.1995.tb01558.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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27
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Brünen-Nieweler C, Meyer F, Heckmann K. Expression of the pheromone 3-encoding gene of Euplotes octocarinatus using a novel bacterial secretion vector. Gene X 1994; 150:187-92. [PMID: 7959050 DOI: 10.1016/0378-1119(94)90882-6] [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: 01/28/2023] Open
Abstract
The pheromone 3-encoding gene (phr3) of Euplotes octocarinatus was expressed in Escherichia coli using a novel expression-secretion vector. The vector, pExSec1, contains a strong and tightly regulated T7 promoter, the corresponding Shine-Dalgarno sequence and the T7 terminator region. Translation starts at the protein A leader sequence followed by the synthetic ZZ sequence of protein A. The expression-secretion modules are embedded in the high-copy-number plasmid vector, pUK21, which carries a kanamycin-resistance marker (KmR). The produced ZZ-pheromone 3 (Phr3) fusion protein was secreted into the culture medium of the host cells. It was isolated by affinity chromatography and was further purified by gel filtration. After refolding with protein disulfide isomerase (PDI), the fusion protein exhibited the same high activity as the native pheromone.
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Affiliation(s)
- C Brünen-Nieweler
- Institut für Allgemeine Zoologie und Genetik, Universität Münster, Germany
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Kuhlmann HW, Schmidt HJ. Extracellular nucleotides are active in evoking the “winged” morph of Euplotes octocarinatus. ACTA ACUST UNITED AC 1994. [DOI: 10.1016/0300-9629(94)90150-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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29
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Abstract
It might appear curious to read about yeast, slime molds and protozoa in a journal dedicated to neuroscience. However, despite their distinct lack of synapses, eukaryotic microorganisms hold a wealth of information relevant to the signal-transduction pathways that underly activity in neuronal receptor cells, particularly those subserving the chemical senses. Microorganisms are sensitive to chemical stimuli from their environment and thus have similarities to receptor neurons of the olfactory system and the taste bud. Here, we introduce receptors, second messengers and effectors responsible for chemosensory signal transduction in yeast mating, sea-urchin spermatozoan chemotaxis, slime-mold aggregation and development, and ciliate chemoresponses.
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Affiliation(s)
- J Van Houten
- Dept of Zoology, University of Vermont, Burlington 05405
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Identification of Cell Surface Polypeptides of the Hypotrich Ciliate Euplotes octocarinatus. ACTA ACUST UNITED AC 1993. [DOI: 10.1016/s0003-9365(11)80327-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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31
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Kuhlmann HW, Sato K. Interspecific mating reactions between Euplotes octocarinatus and Euplotes patella syngen 2. Eur J Protistol 1993. [DOI: 10.1016/s0932-4739(11)80293-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
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32
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Jerka-Dziadosz M, Wiernicka L. Ultrastructural studies on the development of cortical structures in the ciliary pattern mutants of the hypotrich ciliate Paraurostyla weissei. Eur J Protistol 1992. [DOI: 10.1016/s0932-4739(11)80232-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
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34
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Abstract
The ciliated protists (ciliates) offer a unique opportunity to explore the relationship between chemoreception and cell structure. Ciliates resemble chemosensory neurons in their responses to stimuli and presence of cilia. Ciliates have highly patterned surfaces that should permit precise localization of chemoreceptors in relation to effector organelles. Furthermore, ciliates are easy to grow and to manipulate genetically; they can also be readily studied biochemically and by electrophysiological techniques. This review contains a comparative description of the ultrastructural features of the ciliate cell surface relevant to chemoreception, examines the structural features of putative chemoreceptive cilia, and provides a summary of the electron microscopic information available so far bearing on chemoreceptive aspects of swimming, feeding, excretion, endocytosis, and sexual responses of ciliates. The electron microscopic identification and localization of specific chemoreceptive macromolecules and organelles at the molecular level have not yet been achieved in ciliates. These await the development of specific probes for chemoreceptor and transduction macromolecules. Nevertheless, the electron microscope has provided a wealth of information about the surface features of ciliates where chemoreception is believed to take place. Such morphological information will prove essential to a complete understanding of reception and transduction at the molecular level. In the ciliates, major questions to be answered relate to the apportionment of chemoreceptive functions between the cilia and cell soma, the global distribution of receptors in relation to the anterior-posterior, dorsal-ventral, and left-right axes of the cell, and the relationship of receptors to ultrastructural components of the cell coat, cell membrane, and cytoskeleton.
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Affiliation(s)
- L A Hufnagel
- Department of Microbiology, University of Rhode Island, Kingston 02881
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Cheng LJ, Hufnagel LA. Ciliary polypeptides and glycoconjugates of wild-type and mutant Tetrahymena thermophila: starved versus nonstarved. DEVELOPMENTAL GENETICS 1992; 13:26-33. [PMID: 1395138 DOI: 10.1002/dvg.1020130105] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
To investigate the role of cilia in mating interactions of Tetrahymena thermophila, ciliary membrane-rich fractions were isolated from two wild-type strains, a non-discharge mucocyst mutant which possesses mating behavior similar to wild-type, and a mating mutant which is able to costimulate cells of complementary mating type but cannot enter into pair formation. In each case, proteins from the ciliary membrane-rich fractions of starved, mating-competent ("initiated") cells were compared with those from non-starved, mating-incompetent ("non-initiated") cells, by gel electrophoresis and lectin blotting. In stained gels, a 43 kDa polypeptide was reduced or absent in initiated cells but present in non-initiated cells, in all strains. In silver-stained gels, a 25 kDa polypeptide was present in all strains, both initiated and non-initiated. In blots probed with Con A-peroxidase, a 25 kDa glycoprotein was present in ciliary membrane fractions from non-initiated cells and absent in membranes of initiated cells of the two wild-type strains and the mucocyst mutant, but is present in initiated and non-initiated cells of the mating mutant (several hypotheses are presented to explain these findings). In addition, ciliary proteins of the mating mutant included at least two unique Con A-binding polypeptides. Our results support the idea that development of mating competence during starvation involves an extensive remodeling of ciliary membranes, and identify a 25 kDa glycoconjugate as having a potential role in control of pair formation during mating.
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Affiliation(s)
- L J Cheng
- Department of Microbiology, University of Rhode Island, Kingston 02881
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Meyer F, Schmidt HJ, Heckmann K. Pheromone 4 gene of Euplotes octocarinatus. DEVELOPMENTAL GENETICS 1992; 13:16-25. [PMID: 1395137 DOI: 10.1002/dvg.1020130104] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
We have cloned and sequenced a 1.7 kb macronuclear chromosome encoding the pheromone 4 gene of Euplotes octocarinatus. The sequence of the secreted pheromone is preceded by a 42 amino acid leader peptide, which ends with a lysine residue. The sequence coding for the leader peptide contains information for a putative signal peptide and is interrupted by a 772 bp intron as shown by comparison with a cDNA clone. A 64 bp intron and a 145 bp intron interrupt the sequence coding for the secreted pheromone. The three introns contain typical 5' and 3' splice junctions and a putative branch point site. The small introns have a low GC content. The large intron has a GC content similar to that of the pheromone 4 gene exons. The amino acid sequence of pheromone 4, deduced from both the genomic DNA and the cDNA of pheromone 4, shows that the secreted pheromone consists of 85 amino acids. One of its amino acids is encoded by a UGA codon. Since it has been shown for pheromone 3 of E. octocarinatus that UGA is translated as cysteine, it is assumed that the UGA codon encodes cysteine in pheromone 4 as well. The 164 bp noncoding region upstream of the leader peptide is AT-rich and contains an inverted repeat capable of forming a stem-loop structure with a stem of 11 bp. The 151 bp noncoding region at the 3' end of the chromosome contains a putative polyadenylation sequence and an inverted repeat. The macronuclear molecule is flanked by telomeres and carries the pentanucleotide motif TTGAA, located at a distance of 17 nucleotides from the telomeres. This motif has been suggested to be involved in the formation of macronuclear chromosomes.
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Affiliation(s)
- F Meyer
- Institut für Allgemeine Zoologie und Genetik, Universität Münster, Federal Republic of Germany
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Brünen-Nieweler C, Schmidt HJ, Heckmann K. Two introns in the pheromone 3-encoding gene of Euplotes octocarinatus. Gene X 1991; 109:233-7. [PMID: 1765269 DOI: 10.1016/0378-1119(91)90613-g] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The portion of the pheromone 3 (Phr3)-encoding gene (phr3) of Euplotes octocarinatus, corresponding to secreted Phr3 was isolated using the polymerase chain reaction and oligodeoxyribonucleotide primers flanking the Phr3-encoding cDNA. Unexpectedly, the sequence analysis revealed that this gene is interrupted by two introns with lengths of 63 bp and 72 bp. These introns belong to the class of nuclear pre-mRNA introns and contain typical 5'- and 3'-consensus sequences, as well as unique features. Our findings constitute the first example of introns in any Euplotes species and the first case of multiple introns in hypotrichous ciliates. In ciliates such as Euplotes, the macronucleus is the transcriptionally active nucleus. It develops from a micronucleus in a process which involves chromosome breakage and the elimination of up to 95% of the micronuclear genome. The existence of the introns in the macronuclear version of phr3 shows that, in spite of this extensive elimination, some noncoding sequences are nevertheless retained in the macronucleus of hypotrichous ciliates. It was recently discovered by Meyer et al. [Proc. Natl. Acad. Sci. USA 88 (1991) 3758-3761] that the Phr3-encoding cDNA contains three in frame TGA triplets coding for cysteine. The genomic sequence of phr3 confirms this finding.
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Affiliation(s)
- C Brünen-Nieweler
- Institute of General Zoology and Genetics, University of Münster, F.R.G
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Schmidt HJ, Bottke W, Teckentrup W, Heckmann K, Helftenbein E. A comparative study of RNAs from four ciliate groups and a mollusc and data on their poly(A)+ RNA in vitro translation. Eur J Protistol 1991. [DOI: 10.1016/s0932-4739(11)80250-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Fiori PL, Miceli C, Raffioni S, Vallesi A. Specific and common epitopes in mating pheromones of Euplotes raikovi revealed by monoclonal antibodies. THE JOURNAL OF PROTOZOOLOGY 1990; 37:187-90. [PMID: 1694246 DOI: 10.1111/j.1550-7408.1990.tb01125.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Polypeptide mating pheromones Er-1 and Er-2, purified from the supernatant of Euplotes raikovi cultures of mating type I and mating type II, respectively, were used to immunize mice and obtain monoclonal antibodies. Five hybridoma clones producing antibodies specific to the mating pheromones were selected. They were analyzed for immunospecificity by immunoperoxidase assay, immunoblotting, and for their efficacy in inhibition of mating pheromone activity. Monoclonal antibodies from two hybridoma clones recognized only the mating pheromone used as antigen: those from the other three clones reacted, to comparable extents, with both mating pheromones. On the basis of these results it was assumed that two immunogenic sites exist in Er-1 and Er-2, one specific and the other common to both mating pheromones.
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Affiliation(s)
- P L Fiori
- Institute of Microbiology and Virology, University of Sassari, Italy
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41
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Affiliation(s)
- G Beale
- Genetics Department, University of Edinburgh, UK
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42
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Raffioni S, Luporini P, Chait BT, Disper SS, Bradshaw RA. Primary structure of the mating pheromone Er-1 of the ciliate Euplotes raikovi. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(19)81338-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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Kusch J, Heckmann K. Gamones are secreted in Euplotes octocarinatus via the cortical ampules. Eur J Protistol 1988. [DOI: 10.1016/s0932-4739(88)80044-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Schulze Dieckhoff H, Freiburg M, Heckmann K. The isolation of gamones 3 and 4 of Euplotes octocarinatus. EUROPEAN JOURNAL OF BIOCHEMISTRY 1987; 168:89-94. [PMID: 3665921 DOI: 10.1111/j.1432-1033.1987.tb13391.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Gamones 3 and 4 of the ciliate Euplotes octocarinatus were isolated and purified to chromatographic and electrophoretic homogeneity. They are secreted into the culture medium by cells of certain mating types and induce cells of other mating types to unite in pairs and exchange gametic nuclei. The purified gamones are biologically active at concentrations as low as 0.1-1 pM. Both are polypeptides with unusually low pI values of approximately 3.2, and both have a carbohydrate content of less than 2%. Gamone 3 has an Mr of 18,800 and is slightly smaller than gamone 4, which has an Mr of 23,500. Gamone 3 was isolated from the starvation medium of cells homozygous for the mating type allele mt3 and gamone 4 was isolated from the medium of cells homozygous for the mating type allele mt4. Each of the two homozygous cell lines was found to secrete one gamone only.
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46
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A mutation ofEuplotes vannus causing induction of intraclonal conjugation (selfing) in low [K+]o. Cell Mol Life Sci 1987. [DOI: 10.1007/bf01951674] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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47
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Concetti A, Raffioni S, Miceli C, Barra D, Luporini P. Purification to apparent homogeneity of the mating pheromone of mat-1 homozygous Euplotes raikovi. J Biol Chem 1986. [DOI: 10.1016/s0021-9258(18)67424-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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