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Bogaert KA, Zakka EE, Coelho SM, De Clerck O. Polarization of brown algal zygotes. Semin Cell Dev Biol 2023; 134:90-102. [PMID: 35317961 DOI: 10.1016/j.semcdb.2022.03.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 03/01/2022] [Accepted: 03/03/2022] [Indexed: 11/29/2022]
Abstract
Brown algae are a group of multicellular, heterokont algae that have convergently evolved developmental complexity that rivals that of embryophytes, animals or fungi. Early in development, brown algal zygotes establish a basal and an apical pole, which will become respectively the basal system (holdfast) and the apical system (thallus) of the adult alga. Brown algae are interesting models for understanding the establishment of cell polarity in a broad evolutionary context, because they exhibit a large diversity of life cycles, reproductive strategies and, importantly, their zygotes are produced in large quantities free of parental tissue, with symmetry breaking and asymmetric division taking place in a highly synchronous manner. This review describes the current knowledge about the establishment of the apical-basal axis in the model brown seaweeds Ectocarpus, Dictyota, Fucus and Saccharina, highlighting the advantages and specific interests of each system. Ectocarpus is a genetic model system that allows access to the molecular basis of early development and life-cycle control over apical-basal polarity. The oogamous brown alga Fucus, together with emerging comparative models Dictyota and Saccharina, emphasize the diversity of strategies of symmetry breaking in determining a cell polarity vector in brown algae. A comparison with symmetry-breaking mechanisms in land plants, animals and fungi, reveals that the one-step zygote polarisation of Fucus compares well to Saccharomyces budding and Arabidopsis stomata development, while the two-phased symmetry breaking in the Dictyota zygote compares to Schizosaccharomyces fission, the Caenorhabditis anterior-posterior zygote polarisation and Arabidopsis prolate pollen polarisation. The apical-basal patterning in Saccharina zygotes on the other hand, may be seen as analogous to that of land plants. Overall, brown algae have the potential to bring exciting new information on how a single cell gives rise to an entire complex body plan.
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Affiliation(s)
- Kenny A Bogaert
- Phycology Research Group, Department of Biology, Ghent University, Krijgslaan 281 S8, B-9000 Ghent, Belgium.
| | - Eliane E Zakka
- Phycology Research Group, Department of Biology, Ghent University, Krijgslaan 281 S8, B-9000 Ghent, Belgium
| | - Susana M Coelho
- Department of Algal Development and Evolution, Max Planck Institute for Biology, Tübingen, Germany
| | - Olivier De Clerck
- Phycology Research Group, Department of Biology, Ghent University, Krijgslaan 281 S8, B-9000 Ghent, Belgium
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2
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Coelho SM, Umen J. Switching it up: algal insights into sexual transitions. PLANT REPRODUCTION 2021; 34:287-296. [PMID: 34181073 PMCID: PMC8566403 DOI: 10.1007/s00497-021-00417-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 06/02/2021] [Indexed: 05/03/2023]
Abstract
While the process of meiosis is highly conserved across eukaryotes, the sexual systems that govern life cycle phase transitions are surprisingly labile. Switches between sexual systems have profound evolutionary and ecological consequences, in particular for plants, but our understanding of the fundamental mechanisms and ultimate causes underlying these transitions is still surprisingly incomplete. We explore here the idea that brown and green algae may be interesting comparative models that can increase our understanding of relevant processes in plant reproductive biology, from evolution of gamete dimorphism, gametogenesis, sex determination and transitions in sex-determining systems.
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Affiliation(s)
- Susana M Coelho
- Max Planck Institute for Developmental Biology, Max-Planck-Ring 5, 72076, Tübingen, Germany.
| | - James Umen
- Donald Danforth Plant Science Center, St. Louis, MO, 63132, USA
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3
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Abstract
Model organisms are extensively used in research as accessible and convenient systems for studying a particular area or question in biology. Traditionally, only a limited number of organisms have been studied in detail, but modern genomic tools are enabling researchers to extend beyond the set of classical model organisms to include novel species from less-studied phylogenetic groups. This review focuses on model species for an important group of multicellular organisms, the brown algae. The development of genetic and genomic tools for the filamentous brown alga Ectocarpus has led to it emerging as a general model system for this group, but additional models, such as Fucus or Dictyota dichotoma, remain of interest for specific biological questions. In addition, Saccharina japonica has emerged as a model system to directly address applied questions related to algal aquaculture. We discuss the past, present, and future of brown algal model organisms in relation to the opportunities and challenges in brown algal research.
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Affiliation(s)
- Susana M Coelho
- Laboratory of Integrative Biology of Marine Models (LBI2M), Station Biologique de Roscoff (SBR), CNRS, Sorbonne Université, 29680 Roscoff, France;
- Current affiliation: Department of Algal Development and Evolution, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany;
| | - J Mark Cock
- Laboratory of Integrative Biology of Marine Models (LBI2M), Station Biologique de Roscoff (SBR), CNRS, Sorbonne Université, 29680 Roscoff, France;
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Zhou AP, Gan PH, Zong D, Fei X, Zhong YY, Li SQ, Yu JD, He CZ. Bark tissue transcriptome analyses of inverted Populus yunnanensis cuttings reveal the crucial role of plant hormones in response to inversion. PeerJ 2019; 7:e7740. [PMID: 31592192 PMCID: PMC6777492 DOI: 10.7717/peerj.7740] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 08/25/2019] [Indexed: 01/11/2023] Open
Abstract
Inverted cuttings of Populus yunnanensis exhibit an interesting growth response to inversion. This response is characterized by enlargement of the stem above the shoot site, while the upright stem shows obvious outward growth below the shoot site. In this study, we examined transcriptome changes in bark tissue at four positions on upright and inverted cuttings of P. yunnanensis: position B, the upper portion of the stem; position C, the lower portion of the stem; position D, the bottom of new growth; and position E, the top of new growth. The results revealed major transcriptomic changes in the stem, especially at position B, but little alteration was observed in the bark tissue of the new shoot. The differentially expressed genes (DEGs) were mainly assigned to four pathways: plant hormone signal transduction, plant-pathogen interaction, mitogen-activated protein kinase (MAPK) signaling pathway-plant, and adenosine triphosphate-binding cassette (ABC) transporters. Most of these DEGs were involved in at least two pathways. The levels of many hormones, such as auxin (IAA), cytokinin (CTK), gibberellins (GAs), ethylene (ET), and brassinosteroids (BRs), underwent large changes in the inverted cuttings. A coexpression network showed that the top 20 hub unigenes at position B in the upright and inverted cutting groups were associated mainly with the BR and ET signaling pathways, respectively. Furthermore, brassinosteroid insensitive 1-associated receptor kinase 1 (BAK1) in the BR pathway and both ethylene response (ETR) and constitutive triple response 1 (CTR1) in the ET pathway were important hubs that interfaced with multiple pathways.
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Affiliation(s)
- An-Pei Zhou
- Key Laboratory for Forest Genetic and Tree Improvement and Propagation in Universities of Yunnan Province, Southwest Forestry University, Kunming, China
- Key Laboratory of Biodiversity Conservation in Southwest China, State Forestry Administration, Southwest Forestry University, Kunming, China
| | - Pei-Hua Gan
- Key Laboratory for Forest Genetic and Tree Improvement and Propagation in Universities of Yunnan Province, Southwest Forestry University, Kunming, China
- Key Laboratory of Biodiversity Conservation in Southwest China, State Forestry Administration, Southwest Forestry University, Kunming, China
| | - Dan Zong
- Key Laboratory for Forest Genetic and Tree Improvement and Propagation in Universities of Yunnan Province, Southwest Forestry University, Kunming, China
- Key Laboratory of Biodiversity Conservation in Southwest China, State Forestry Administration, Southwest Forestry University, Kunming, China
| | - Xuan Fei
- Key Laboratory for Forest Genetic and Tree Improvement and Propagation in Universities of Yunnan Province, Southwest Forestry University, Kunming, China
- Key Laboratory of Biodiversity Conservation in Southwest China, State Forestry Administration, Southwest Forestry University, Kunming, China
| | - Yuan-Yuan Zhong
- Key Laboratory for Forest Genetic and Tree Improvement and Propagation in Universities of Yunnan Province, Southwest Forestry University, Kunming, China
- Key Laboratory of Biodiversity Conservation in Southwest China, State Forestry Administration, Southwest Forestry University, Kunming, China
| | - Si-Qi Li
- Key Laboratory for Forest Genetic and Tree Improvement and Propagation in Universities of Yunnan Province, Southwest Forestry University, Kunming, China
- Key Laboratory of Biodiversity Conservation in Southwest China, State Forestry Administration, Southwest Forestry University, Kunming, China
| | - Jin-De Yu
- Key Laboratory for Forest Genetic and Tree Improvement and Propagation in Universities of Yunnan Province, Southwest Forestry University, Kunming, China
| | - Cheng-Zhong He
- Key Laboratory for Forest Genetic and Tree Improvement and Propagation in Universities of Yunnan Province, Southwest Forestry University, Kunming, China
- Key Laboratory of Biodiversity Conservation in Southwest China, State Forestry Administration, Southwest Forestry University, Kunming, China
- Key Laboratory for Forest Resources Conservation and Utilization in the Southwest Mountains of China, Ministry of Education, Southwest Forestry University, Kunming, China
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Charrier B, Abreu MH, Araujo R, Bruhn A, Coates JC, De Clerck O, Katsaros C, Robaina RR, Wichard T. Furthering knowledge of seaweed growth and development to facilitate sustainable aquaculture. THE NEW PHYTOLOGIST 2017; 216:967-975. [PMID: 28800196 DOI: 10.1111/nph.14728] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Macroalgae (seaweeds) are the subject of increasing interest for their potential as a source of valuable, sustainable biomass in the food, feed, chemical and pharmaceutical industries. Compared with microalgae, the pace of knowledge acquisition in seaweeds is slower despite the availability of whole-genome sequences and model organisms for the major seaweed groups. This is partly a consequence of specific hurdles related to the large size of these organisms and their slow growth. As a result, this basic scientific field is falling behind, despite the societal and economic importance of these organisms. Here, we argue that sustainable management of seaweed aquaculture requires fundamental understanding of the underlying biological mechanisms controlling macroalgal life cycles - from the production of germ cells to the growth and fertility of the adult organisms - using diverse approaches requiring a broad range of technological tools. This Viewpoint highlights several examples of basic research on macroalgal developmental biology that could enable the step-changes which are required to adequately meet the demands of the aquaculture sector.
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Affiliation(s)
- Bénédicte Charrier
- Morphogenesis of Macroalgae, UMR8227, CNRS-UPMC, Station Biologique, Roscoff, 29680, France
| | - Maria Helena Abreu
- Travessa Alexandre da Conceição, ALGAplus Lda, Ílhavo, 3830-196, Portugal
| | - Rita Araujo
- Water and Marine Resources Unit, Joint Research Centre - Directorate for Sustainable Resources, European Commission, via E. Fermi, Ispra (VA), 2749-21027, Italy
| | - Annette Bruhn
- Department of BioScience, Aarhus University, Vejlsøvej 25, Silkeborg, 8600, Denmark
| | - Juliet C Coates
- School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Olivier De Clerck
- Department of Biology, Ghent University, Krijgslaan 281 S8, Ghent, 9000, Belgium
| | - Christos Katsaros
- Department of Biology, Morphogenesis of Macroalgae, National and Kapodistrian University of Athens, Athens, 157 84, Greece
| | - Rafael R Robaina
- Facultad de Ciencias del Mar, Universidad de Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, 35017, Spain
| | - Thomas Wichard
- Institute for Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, Lessingstr. 8, Jena, 07743, Germany
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Torode TA, Marcus SE, Jam M, Tonon T, Blackburn RS, Hervé C, Knox JP. Monoclonal antibodies directed to fucoidan preparations from brown algae. PLoS One 2015; 10:e0118366. [PMID: 25692870 PMCID: PMC4333822 DOI: 10.1371/journal.pone.0118366] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 01/15/2015] [Indexed: 11/28/2022] Open
Abstract
Cell walls of the brown algae contain a diverse range of polysaccharides with useful bioactivities. The precise structures of the sulfated fucan/fucoidan group of polysaccharides and their roles in generating cell wall architectures and cell properties are not known in detail. Four rat monoclonal antibodies, BAM1 to BAM4, directed to sulfated fucan preparations, have been generated and used to dissect the heterogeneity of brown algal cell wall polysaccharides. BAM1 and BAM4, respectively, bind to a non-sulfated epitope and a sulfated epitope present in the sulfated fucan preparations. BAM2 and BAM3 identified additional distinct epitopes present in the fucoidan preparations. All four epitopes, not yet fully characterised, occur widely within the major brown algal taxonomic groups and show divergent distribution patterns in tissues. The analysis of cell wall extractions and fluorescence imaging reveal differences in the occurrence of the BAM1 to BAM4 epitopes in various tissues of Fucus vesiculosus. In Ectocarpus subulatus, a species closely related to the brown algal model Ectocarpus siliculosus, the BAM4 sulfated epitope was modulated in relation to salinity levels. This new set of monoclonal antibodies will be useful for the dissection of the highly complex and yet poorly resolved sulfated polysaccharides in the brown algae in relation to their ecological and economic significance.
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Affiliation(s)
- Thomas A. Torode
- Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Susan E. Marcus
- Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Murielle Jam
- Sorbonne Universités, UPMC Univ Paris 06, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, Roscoff, France
- CNRS, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, Roscoff, France
| | - Thierry Tonon
- Sorbonne Universités, UPMC Univ Paris 06, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, Roscoff, France
- CNRS, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, Roscoff, France
| | - Richard S. Blackburn
- Sustainable Materials Research Group, Centre for Technical Textiles, University of Leeds, Leeds, United Kingdom
| | - Cécile Hervé
- Sorbonne Universités, UPMC Univ Paris 06, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, Roscoff, France
- CNRS, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, Roscoff, France
| | - J. Paul Knox
- Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
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7
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Lipinska AP, D’hondt S, Van Damme EJM, De Clerck O. Uncovering the genetic basis for early isogamete differentiation: a case study of Ectocarpus siliculosus. BMC Genomics 2013; 14:909. [PMID: 24359479 PMCID: PMC3879662 DOI: 10.1186/1471-2164-14-909] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Accepted: 12/17/2013] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND The phenomenon of sexual reproduction characterizes nearly all eukaryotes, with anisogamy being the most prevalent form of gamete discrimination. Since dimorphic gametes most likely descend from equal-sized specialized germ cells, identifying the genetic bases of the early functional diversification in isogametes can provide better understanding of the evolution of sexual dimorphism. However, despite the potential importance to the evolutionary biology field, no comprehensive survey of the transcriptome profiling in isomorphic gametes has been reported hitherto. RESULTS Gamete differentiation on the genomic level was investigated using Ectocarpus siliculosus, a model organism for brown algal lineage which displays an isogamous sexual reproduction cycle. Transcriptome libraries of male and female gametes were generated using Next Generation Sequencing technology (SOLiD) and analyzed to identify differentially regulated genes and pathways with potential roles in fertilization and gamete specialization. Gamete transcriptomes showed a high level of complexity with a large portion of gender specific gene expression. Our results indicate that over 4,000 of expressed genes are differentially regulated between male and female, including sequences related to cell movement, carbohydrate and lipid metabolism, signaling, transport and RNA processing. CONCLUSIONS This first comprehensive transcriptomic study of protist isogametes describes considerable adaptation to distinct sexual roles, suggesting that functional anisogamy precedes morphological differentiation. Several sex-biased genes and pathways with a putative role in reproduction were identified, providing the basis for more detailed investigations of the mechanisms underlying evolution of mating types and sexual dimorphism.
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Affiliation(s)
- Agnieszka P Lipinska
- Phycology Research Group and Center for Molecular Phylogenetics and Evolution, Ghent University, Krijgslaan 281, Building S8, 9000 Ghent, Belgium
| | - Sofie D’hondt
- Phycology Research Group and Center for Molecular Phylogenetics and Evolution, Ghent University, Krijgslaan 281, Building S8, 9000 Ghent, Belgium
| | - Els JM Van Damme
- Department of Molecular Biotechnology, Laboratory of Biochemistry and Glycobiology, Ghent University, Coupure Links 653, 9000 Gent, Belgium
| | - Olivier De Clerck
- Phycology Research Group and Center for Molecular Phylogenetics and Evolution, Ghent University, Krijgslaan 281, Building S8, 9000 Ghent, Belgium
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8
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Farnham G, Strittmatter M, Coelho S, Cock JM, Brownlee C. Gene silencing in Fucus embryos: developmental consequences of RNAi-mediated cytoskeletal disruption. JOURNAL OF PHYCOLOGY 2013; 49:819-29. [PMID: 27007308 DOI: 10.1111/jpy.12096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2012] [Accepted: 06/02/2013] [Indexed: 05/10/2023]
Abstract
Brown algae (Phaeophyceae) are an important algal class that play a range of key ecological roles. They are often important components of rocky shore communities. A number of members of the Fucales and Ectocarpales have provided models for the study of multicellular evolution, reproductive biology and polarized development. Indeed the fucoid algae exhibit the unusual feature of inducible embryo polarization, allowing many classical studies of polarity induction. The potential of further studies of brown algae in these important areas has been increasingly hindered by the absence of tools for manipulation of gene expression that would facilitate further mechanistic analysis and gene function studies at a molecular level. The aim of this study was to establish a method that would allow the analysis of gene function through RNAi-mediated gene knockdown. We show that injection of double-stranded RNA (dsRNA) corresponding to an α-tubulin gene into Fucus serratus Linnaeus zygotes induces the loss of a large proportion of the microtubule cytoskeleton, leading to growth arrest and disruption of cell division. Injection of dsRNA targeting β-actin led to reduced rhizoid growth, enlarged cells and the failure to develop apical hair cells. The silencing effect on actin expression was maintained for 3 months. These results indicate that the Fucus embryo possesses a functional RNA interference system that can be exploited to investigate gene function during embryogenesis.
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Affiliation(s)
- Garry Farnham
- Marine Biological Association, The Laboratory, Citadel Hill, Plymouth, PL1 2PB, UK
| | - Martina Strittmatter
- The Marine Plants and Biomolecules Laboratory, CNRS, UMR 7139, UPMC University Paris 06, UMR 7139, Station Biologique de Roscoff, Place Georges Teissier, BP74, Roscoff Cedex, 29682, France
| | - Susana Coelho
- The Marine Plants and Biomolecules Laboratory, CNRS, UMR 7139, UPMC University Paris 06, UMR 7139, Station Biologique de Roscoff, Place Georges Teissier, BP74, Roscoff Cedex, 29682, France
| | - Jeremy Mark Cock
- The Marine Plants and Biomolecules Laboratory, CNRS, UMR 7139, UPMC University Paris 06, UMR 7139, Station Biologique de Roscoff, Place Georges Teissier, BP74, Roscoff Cedex, 29682, France
| | - Colin Brownlee
- Marine Biological Association, The Laboratory, Citadel Hill, Plymouth, PL1 2PB, UK
- School of Ocean and Earth Sciences, University of Southampton, National Oceanography Centre, Southampton, SO14 3ZH, UK
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9
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Abstract
Brown algae are an extremely interesting, but surprisingly poorly explored, group of organisms. They are one of only five eukaryotic lineages to have independently evolved complex multicellularity, which they express through a wide variety of morphologies ranging from uniseriate branched filaments to complex parenchymatous thalli with multiple cell types. Despite their very distinct evolutionary history, brown algae and land plants share a striking amount of developmental features. This has led to an interest in several aspects of brown algal development, including embryogenesis, polarity, cell cycle, asymmetric cell division and a putative role for plant hormone signalling. This review describes how investigations using brown algal models have helped to increase our understanding of the processes controlling early embryo development, in particular polarization, axis formation and asymmetric cell division. Additionally, the diversity of life cycles in the brown lineage and the emergence of Ectocarpus as a powerful model organism, are affording interesting insights on the molecular mechanisms underlying haploid-diploid life cycles. The use of these and other emerging brown algal models will undoubtedly add to our knowledge on the mechanisms that regulate development in multicellular photosynthetic organisms.
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Affiliation(s)
- Kenny A Bogaert
- Phycology Research Group, Department of Biology, Center for Molecular Phylogenetics and Evolution, Ghent University, Ghent, Belgium
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10
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De Smet I, Beeckman T. Asymmetric cell division in land plants and algae: the driving force for differentiation. Nat Rev Mol Cell Biol 2011; 12:177-88. [PMID: 21346731 DOI: 10.1038/nrm3064] [Citation(s) in RCA: 144] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Asymmetric cell division generates two cells with different fates and has an important role in plant development. It produces distinct cell types and new organs, and maintains stem cell niches. To handle the constraints of having immobile cells, plants possess numerous unique features to obtain asymmetry, such as specific regulators of intrinsic polarity. Although several components have not yet been identified, new findings, together with knowledge from different developmental systems, now allow us to take an important step towards a mechanistic overview of asymmetric cell division in plants and algae. Strikingly, several key regulators are used for different developmental processes, and common mechanisms can be recognized.
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Affiliation(s)
- Ive De Smet
- Plant and Crop Sciences Division, School of Biosciences, University of Nottingham, Loughborough LE12 5RD, UK.
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11
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Hable WE, Hart PE. Signaling mechanisms in the establishment of plant and fucoid algal polarity. Mol Reprod Dev 2010; 77:751-8. [PMID: 20803733 DOI: 10.1002/mrd.21199] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
The establishment of polarity is a fundamental property of most cells. In tip-growing plant and in fucoid algal cells, polarization specifies a growth pole, the center of localized secretion of new plasma membrane and cell wall material, generating a protrusion with a dome-shaped apex. Although much progress has been made concerning the cellular machinery required to execute tip growth, less is known regarding the signaling mechanisms involved in selecting the growth site and regulating vectorial cell division and expansion. Fucoid algal zygotes use extrinsic cues to orient their growth axes and are thus well-suited for studies of de novo selection of an axis. This process has been investigated largely by both pharmacological and immuno-localization studies. In tip growing plant cells, polarity is often predetermined, as in the formation of root hairs or moss protonema branches. More focus has been on genomic and genetic studies to reveal the molecules involved in expressing a growth axis. Here we review the common roles of the cytoskeleton and signal transduction pathways in the formation of a developmental axis in fucoid algal cells and the control of tip growth in higher plant cells.
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Affiliation(s)
- Whitney E Hable
- University of Massachusetts Dartmouth, Dartmouth, Massachusetts 02747, USA.
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12
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Peters NT, Kropf DL. Asymmetric microtubule arrays organize the endoplasmic reticulum during polarity establishment in the brown alga Silvetia compressa. Cytoskeleton (Hoboken) 2010; 67:102-11. [PMID: 20169534 DOI: 10.1002/cm.20427] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2009] [Accepted: 12/16/2009] [Indexed: 11/09/2022]
Abstract
Polarity is a fundamental characteristic of most cell types, and is crucial to early development of the brown alga Silvetia compressa. In eukaryotes the cytoskeleton plays an important role in generating cellular asymmetries. While it is known that F-actin is required for polarization and growth in most tip-growing cells, the roles of microtubules are less clear. We examined the distribution and function of microtubules in S. compressa zygotes as they polarized and initiated tip growth. Microtubules formed asymmetric arrays oriented toward the rhizoid hemisphere early in the polarization process. These arrays were spatially coupled with polar adhesive deposition, a marker of the rhizoid pole. Reorientation of the light vector during polarization led to sequential redistribution of polar axis components, with the microtubules and the polar axis reorienting nearly simultaneously, followed by cell wall loosening and then deposition of new polar adhesive. These findings suggested that microtubules may organize and target endomembrane arrays. We therefore examined the distribution of the endoplasmic reticulum during polarization and found it colocalized with microtubules and became targeted toward the rhizoid pole as microtubule asymmetry was generated. Endoplasmic reticulum association with microtubules remained fully intact following pharmacological disruption of F-actin, whereas microtubule disruption led to aggregation of the endoplasmic reticulum around the nucleus. We propose that brown algae utilize microtubules for organization of the endoplasmic reticulum and migration of exocytotic components to the rhizoid cortex, and present a model for polarity establishment to account for these new findings.
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Affiliation(s)
- Nick T Peters
- Department of Biology, University of Utah, Salt Lake City, USA.
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Mikami K, Li L, Takahashi M, Saga N. Photosynthesis-dependent Ca2+ influx and functional diversity between phospholipases in the formation of cell polarity in migrating cells of red algae. PLANT SIGNALING & BEHAVIOR 2009; 4:911-913. [PMID: 19938378 PMCID: PMC2802806 DOI: 10.4161/psb.4.9.9534] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2009] [Accepted: 07/16/2009] [Indexed: 05/28/2023]
Abstract
Unicellular spore cells, designated as monospores (also called archeospores), are well known as migrating plant cells, in which establishment of the anterior-posterior axis directs asymmetrical distribution of F-actin. Since the mechanisms of cell polarity formation are not yet fully elucidated in monospores, we investigated the roles of phosphoinositide signaling systems and Ca2+ mobilization in migration. Although we have already found the critical involvement of phosphatidylinositol 3-kinase in the establishment of cell polarity, we recently demonstrated the important roles of extracellular Ca2+ influx, phospholipase C (PLC) and phospholipase D (PLD). The remarkable characteristics of these factors are that Ca2+ influx depends on photosynthetic activity and that PLC and PLD play roles in the establishment and maintenance of cell polarity, respectively. These findings could provide new insight into the regulation of migration in eukaryotic cells.
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Affiliation(s)
- Koji Mikami
- Faculty of Fisheries Sciences, Hokkaido University, Hakodate, Japan.
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14
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Li L, Saga N, Mikami K. Ca2+ influx and phosphoinositide signalling are essential for the establishment and maintenance of cell polarity in monospores from the red alga Porphyra yezoensis. JOURNAL OF EXPERIMENTAL BOTANY 2009; 60:3477-89. [PMID: 19531546 PMCID: PMC2724695 DOI: 10.1093/jxb/erp183] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2009] [Revised: 05/12/2009] [Accepted: 05/13/2009] [Indexed: 05/16/2023]
Abstract
The asymmetrical distribution of F-actin directed by cell polarity has been observed during the migration of monospores from the red alga Porphyra yezoensis. The significance of Ca2+ influx and phosphoinositide signalling during the formation of cell polarity in migrating monospores was analysed pharmacologically. The results indicate that the inhibition of the establishment of cell polarity, as judged by the ability of F-actin to localize asymmetrically, cell wall synthesis, and development into germlings, occurred when monospores were treated with inhibitors of the Ca2+ permeable channel, phospholipase C (PLC), diacylglycerol kinase, and inositol-1,4,5-trisphosphate receptor. Moreover, it was also found that light triggered the establishment of cell polarity via photosynthetic activity but not its direction, indicating that the Ca2+ influx and PLC activation required for the establishment of cell polarity are light dependent. By contrast, inhibition of phospholipase D (PLD) prevented the migration of monospores but not the asymmetrical localization of F-actin. Taken together, these findings suggest that there is functional diversity between the PLC and PLD signalling systems in terms of the formation of cell polarity; the former being critical for the light-dependent establishment of cell polarity and the latter playing a role in the maintenance of established cell polarity.
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Affiliation(s)
- Lin Li
- Graduate School of Fisheries Sciences, Hokkaido University, Hakodate 041-8611, Japan
| | - Naotsune Saga
- Faculty of Fisheries Sciences, Hokkaido University, 3-1-1 Minato-cho, Hakodate 041-8611, Japan
| | - Koji Mikami
- Faculty of Fisheries Sciences, Hokkaido University, 3-1-1 Minato-cho, Hakodate 041-8611, Japan
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Muzzy RA, Hable WE. Rac1 function during fucoid development. PLANT SIGNALING & BEHAVIOR 2008; 3:717-719. [PMID: 19704838 PMCID: PMC2634569 DOI: 10.4161/psb.3.9.6457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2008] [Accepted: 06/18/2008] [Indexed: 05/28/2023]
Abstract
Morphogenesis in fucoid algae begins with adhesive secretion and rhizoid germination, developmental events that secure the alga within the intertidal zone. The importance of the actin cytoskeleton during these processes has been well established; but in general, little is known about actin regulation within the stramenopile lineage. Based on conserved strategies for regulation of actin in other lineages, co-localization of the Arp2/3 complex with actin structures that are essential for rhizoid formation may implicate members of the Rho family of small GTPases in the signaling pathway(s) regulating actin polymerization during fucoid development. Our lab recently demonstrated Rac1 dependent regulation of endomembrane polarization, polarization of adhesive secretion, germination and tip growth in the fucoid brown alga Silvetia compressa. We also present new evidence revealing Rac1 localization during germination in S. compressa, and show that membrane localization is essential for proper Rac1 function.
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Affiliation(s)
- Rachel A Muzzy
- University of Massachusetts Dartmouth; Department of Biology; North Dartmouth, Massachusetts USA
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Hable WE, Reddy S, Julien L. The Rac1 inhibitor, NSC23766, depolarizes adhesive secretion, endomembrane cycling, and tip growth in the fucoid alga, Silvetia compressa. PLANTA 2008; 227:991-1000. [PMID: 18183417 DOI: 10.1007/s00425-007-0673-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2007] [Accepted: 11/23/2007] [Indexed: 05/25/2023]
Abstract
Proper cell morphogenesis is dependent on the establishment and expression of cellular polarity. In the fucoid zygote, cell shape is critical for establishing the developmental pattern of the adult, and is achieved by guiding insertion of new membrane and wall to the rhizoid tip. Selection and growth of the appropriate tip site are accompanied by formation of dynamic actin arrays associated with the actin-nucleating Arp2/3 complex. In eukaryotes, a major pathway for activation of the Arp2/3 complex is via the Rho family GTPase, Rac1, which stimulates the Scar/WAVE complex. To determine whether Rac1 controls actin nucleation in Silvetia compressa (J. Agardh) E. Serrao, T. O. Cho, S. M. Boo et Brawley, we tested the effects of the Rac1-specific inhibitory compound, NSC23766, on actin dependent processes and on actin arrays. We found that NSC23766 disrupted polar secretion of adhesive, polarization of endomembranes, and tip-focused growth in the rhizoid. Similarly, NSC23766 altered actin and Arp2 localization in the growing rhizoid. In contrast, NSC23766 had no effect on selection of the growth site or on cytokinesis. These data suggest that Rac1 participates in nucleation of specific actin arrays in the developing zygote.
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Affiliation(s)
- Whitney E Hable
- Department of Biology, University of Massachusetts Dartmouth, North Dartmouth, MA 02747-2300, USA.
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Peters NT, Logan KO, Miller AC, Kropf DL. Phospholipase D Signaling Regulates Microtubule Organization in the Fucoid Alga Silvetia compressa. ACTA ACUST UNITED AC 2007; 48:1764-74. [DOI: 10.1093/pcp/pcm149] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Bischoff M, Schnabel R. A posterior centre establishes and maintains polarity of the Caenorhabditis elegans embryo by a Wnt-dependent relay mechanism. PLoS Biol 2007; 4:e396. [PMID: 17121454 PMCID: PMC1637133 DOI: 10.1371/journal.pbio.0040396] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2006] [Accepted: 09/20/2006] [Indexed: 11/19/2022] Open
Abstract
Cellular polarity is a general feature of animal development. However, the mechanisms that establish and maintain polarity in a field of cells or even in the whole embryo remain elusive. Here we provide evidence that in the Caenorhabditis elegans embryo, the descendants of P1, the posterior blastomere of the 2-cell stage, constitute a polarising centre that orients the cell divisions of most of the embryo. This polarisation depends on a MOM-2/Wnt signal originating from the P1 descendants. Furthermore, we show that the MOM-2/Wnt signal is transduced from cell to cell by a relay mechanism. Our findings suggest how polarity is first established and then maintained in a field of cells. According to this model, the relay mechanism constantly orients the polarity of all cells towards the polarising centre, thus organising the whole embryo. This model may also apply to other systems such as Drosophila and vertebrates.
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Affiliation(s)
- Marcus Bischoff
- Technische Universität Braunschweig Carolo Wilhelmina, Institut für Genetik, Braunschweig, Germany
| | - Ralf Schnabel
- Technische Universität Braunschweig Carolo Wilhelmina, Institut für Genetik, Braunschweig, Germany
- * To whom correspondence should be addressed. E-mail:
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Katsaros C, Karyophyllis D, Galatis B. Cytoskeleton and morphogenesis in brown algae. ANNALS OF BOTANY 2006; 97:679-93. [PMID: 16467352 PMCID: PMC2803427 DOI: 10.1093/aob/mcl023] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2005] [Revised: 11/05/2005] [Accepted: 11/28/2005] [Indexed: 05/06/2023]
Abstract
BACKGROUND Morphogenesis on a cellular level includes processes in which cytoskeleton and cell wall expansion are strongly involved. In brown algal zygotes, microtubules (MTs) and actin filaments (AFs) participate in polarity axis fixation, cell division and tip growth. Brown algal vegetative cells lack a cortical MT cytoskeleton, and are characterized by centriole-bearing centrosomes, which function as microtubule organizing centres. SCOPE Extensive electron microscope and immunofluorescence studies of MT organization in different types of brown algal cells have shown that MTs constitute a major cytoskeletal component, indispensable for cell morphogenesis. Apart from participating in mitosis and cytokinesis, they are also involved in the expression and maintenance of polarity of particular cell types. Disruption of MTs after Nocodazole treatment inhibits cell growth, causing bulging and/or bending of apical cells, thickening of the tip cell wall, and affecting the nuclear positioning. Staining of F-actin using Rhodamine-Phalloidin, revealed a rich network consisting of perinuclear, endoplasmic and cortical AFs. AFs participate in mitosis by the organization of an F-actin spindle and in cytokinesis by an F-actin disc. They are also involved in the maintenance of polarity of apical cells, as well as in lateral branch initiation. The cortical system of AFs was found related to the orientation of cellulose microfibrils (MFs), and therefore to cell wall morphogenesis. This is expressed by the coincidence in the orientation between cortical AFs and the depositing MFs. Treatment with cytochalasin B inhibits mitosis and cytokinesis, as well as tip growth of apical cells, and causes abnormal deposition of MFs. CONCLUSIONS Both the cytoskeletal elements studied so far, i.e. MTs and AFs are implicated in brown algal cell morphogenesis, expressed in their relationship with cell wall morphogenesis, polarization, spindle organization and cytokinetic mechanism. The novelty is the role of AFs and their possible co-operation with MTs.
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Affiliation(s)
- Christos Katsaros
- University of Athens, Faculty of Biology, Department of Botany, Athens 157 84, Greece.
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Hadley R, Hable WE, Kropf DL. Polarization of the endomembrane system is an early event in fucoid zygote development. BMC PLANT BIOLOGY 2006; 6:5. [PMID: 16504093 PMCID: PMC1397835 DOI: 10.1186/1471-2229-6-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2005] [Accepted: 02/23/2006] [Indexed: 05/06/2023]
Abstract
BACKGROUND Fucoid zygotes are excellent experimental organisms for investigating mechanisms that establish cell polarity and determine the site of tip growth. A common feature of polarity establishment is targeting endocytosis and exocytosis (secretion) to localized cortical domains. We have investigated the spatiotemporal development of endomembrane asymmetry in photopolarizing zygotes, and examined the underlying cellular physiology. RESULTS The vital dye FM4-64 was used to visualize endomembranes. The endomembrane system preferentially accumulated at the rhizoid (growth) pole within 4 h of fertilization. The polarized endomembrane array was initially labile and reoriented when the developmental axis changed direction in response to changing light cues. Pharmacological studies indicated that vesicle trafficking, actin and microtubules were needed to maintain endomembrane polarity. In addition, endocytosis required a functional cortical actin cytoskeleton. CONCLUSION Endomembrane polarization is an early event in polarity establishment, beginning very soon after photolocalization of cortical actin to the presumptive rhizoid site. Targeting of endocytosis and secretion to the rhizoid cortex contributes to membrane asymmetry. We suggest that microtubule-actin interactions, possibly involving microtubule capture and stabilization at actin-rich sites in the rhizoid, may organize the endomembrane array.
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Affiliation(s)
- Rhett Hadley
- University of Utah, Department of Biology, 257 South 1400 East, Salt Lake City, Utah 84112-0840, USA
| | - Whitney E Hable
- University of Utah, Department of Biology, 257 South 1400 East, Salt Lake City, Utah 84112-0840, USA
- Department of Biology, University of Massachusetts Dartmouth, 285 Old Westport Road, North Dartmouth MA 02747, USA
| | - Darryl L Kropf
- University of Utah, Department of Biology, 257 South 1400 East, Salt Lake City, Utah 84112-0840, USA
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McQueen-Mason S. Cell walls: the boundaries of plant development. The role of the extracellular matrix in the control of plant development: the 13th New Phytologist Symposium, London, UK, January 2005. THE NEW PHYTOLOGIST 2005; 166:717-22. [PMID: 15869636 DOI: 10.1111/j.1469-8137.2005.01447.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Affiliation(s)
- Simon McQueen-Mason
- CNAP, Biology Department, University of York, PO Box 373, York, YO10 5YW, UK. email
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Hable WE, Kropf DL. The Arp2/3 complex nucleates actin arrays during zygote polarity establishment and growth. CELL MOTILITY AND THE CYTOSKELETON 2005; 61:9-20. [PMID: 15776461 DOI: 10.1002/cm.20059] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Previous work has demonstrated that dynamic actin arrays are important for axis establishment and polar growth in the fucoid zygote, Silvetia compressa. Transitions between these arrays are mediated by depolymerization of an existing array and polymerization of a new array. To begin to understand how polymerization of new arrays might be regulated, we investigated the role of the highly conserved, actin-nucleating, Actin-related protein 2/3 (Arp2/3) complex. Arp2, a subunit of the complex, was cloned and peptide antibodies were raised to the C-terminal domain. In immunolocalization studies of polarizing zygotes, actin and Arp2 colocalized around the nucleus and in a patch at the rhizoid pole. In germinated zygotes, a cone of Arp2 and actin extended from the nucleus to the subapex. Within the rhizoid tip, three structural zones were observed in the majority of zygotes: the extreme apex was devoid of label, the subapex was enriched for Arp2, and further back both actin and Arp2 were present. This zonation suggests that actin nucleation occurs at the leading edge of the cone, in the Arp2-enriched region. In two sets of experiments, we showed that tip zonation is important for growth. First, pharmacological treatments that disrupted Arp2/actin zonation arrested tip growth. Second, changes in the direction of tip growth during negative phototropism were preceded by a reorientation of the zonation in accordance with the new growth direction. This work represents the first investigation of Arp2/3 complex localization in tip-growing algal cells.
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Affiliation(s)
- Whitney E Hable
- Department of Biology, University of Massachusetts Dartmouth, North Dartmouth, MA 02747-2300, USA.
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