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Nanes Sarfati D, Xue Y, Song ES, Byrne A, Le D, Darmanis S, Quake SR, Burlacot A, Sikes J, Wang B. Coordinated wound responses in a regenerative animal-algal holobiont. Nat Commun 2024; 15:4032. [PMID: 38740753 DOI: 10.1038/s41467-024-48366-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 04/24/2024] [Indexed: 05/16/2024] Open
Abstract
Animal regeneration involves coordinated responses across cell types throughout the animal body. In endosymbiotic animals, whether and how symbionts react to host injury and how cellular responses are integrated across species remain unexplored. Here, we study the acoel Convolutriloba longifissura, which hosts symbiotic Tetraselmis sp. green algae and can regenerate entire bodies from tissue fragments. We show that animal injury causes a decline in the photosynthetic efficiency of the symbiotic algae, alongside two distinct, sequential waves of transcriptional responses in acoel and algal cells. The initial algal response is characterized by the upregulation of a cohort of photosynthesis-related genes, though photosynthesis is not necessary for regeneration. A conserved animal transcription factor, runt, is induced after injury and required for acoel regeneration. Knockdown of Cl-runt dampens transcriptional responses in both species and further reduces algal photosynthetic efficiency post-injury. Our results suggest that the holobiont functions as an integrated unit of biological organization by coordinating molecular networks across species through the runt-dependent animal regeneration program.
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Affiliation(s)
| | - Yuan Xue
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Eun Sun Song
- Department of Applied Physics, Stanford University, Stanford, CA, USA
| | | | - Daniel Le
- Chan Zuckerberg Biohub, San Francisco, CA, USA
| | | | - Stephen R Quake
- Department of Bioengineering, Stanford University, Stanford, CA, USA
- Department of Applied Physics, Stanford University, Stanford, CA, USA
| | - Adrien Burlacot
- Department of Biology, Stanford University, Stanford, CA, USA
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, USA
| | - James Sikes
- Department of Biology, University of San Francisco, San Francisco, CA, USA.
| | - Bo Wang
- Department of Bioengineering, Stanford University, Stanford, CA, USA.
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA, USA.
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2
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Nakamura M, Oguchi K, Sato DS, Kato S, Okanishi M, Hayashi Y, Aguado MT, Miura T. Morphological, histological and gene-expression analyses on stolonization in the Japanese Green Syllid, Megasyllis nipponica (Annelida, Syllidae). Sci Rep 2023; 13:19419. [PMID: 37993494 PMCID: PMC10665476 DOI: 10.1038/s41598-023-46358-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 10/31/2023] [Indexed: 11/24/2023] Open
Abstract
Benthic annelids belonging to the family Syllidae (Annelida, Errantia, Phyllodocida) exhibit a unique reproduction mode called "schizogamy" or "stolonization", in which the posterior body part filled with gametes detaches from the original body, as a reproductive unit (stolon) that autonomously swims and spawns. In this study, morphological and histological observations on the developmental processes during stolonization were carried out in Megasyllis nipponica. Results suggest that the stolon formation started with maturation of gonads, followed by the formation of a head ganglion in the anteriormost segment of the developing stolon. Then, the detailed stolon-specific structures such as stolon eyes and notochaetae were formed. Furthermore, expression profiles of genes involved in the anterior-posterior identity (Hox genes), head determination, germ-line, and hormone regulation were compared between anterior and posterior body parts during the stolonization process. The results reveal that, in the posterior body part, genes for gonadal development were up-regulated, followed by hormone-related genes and head-determination genes. Unexpectedly, Hox genes known to identify body parts along the anterior-posterior axis showed no significant temporal expression changes. These findings suggest that during stolonization, gonad development induces the head formation of a stolon, without up-regulation of anterior Hox genes.
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Affiliation(s)
- Mayuko Nakamura
- Misaki Marine Biological Station, School of Science, The University of Tokyo, Misaki, Miura, Kanagawa, 238-0225, Japan
| | - Kohei Oguchi
- Misaki Marine Biological Station, School of Science, The University of Tokyo, Misaki, Miura, Kanagawa, 238-0225, Japan
| | - Daisuke S Sato
- Misaki Marine Biological Station, School of Science, The University of Tokyo, Misaki, Miura, Kanagawa, 238-0225, Japan
| | - Sumika Kato
- Misaki Marine Biological Station, School of Science, The University of Tokyo, Misaki, Miura, Kanagawa, 238-0225, Japan
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Hongo, Bunkyo, Tokyo, 113-0033, Japan
| | - Masanori Okanishi
- Misaki Marine Biological Station, School of Science, The University of Tokyo, Misaki, Miura, Kanagawa, 238-0225, Japan
- Faculty of Human Environmental Studies, Hiroshima Shudo University, Ozuka-Higashi, Asaminami, Hiroshima, 731-3195, Japan
| | - Yoshinobu Hayashi
- Department of Biology, Keio University, Hiyoshi, Yokohama, 223-8521, Japan
| | - M Teresa Aguado
- Animal Evolution and Biodiversity, Georg-August-Universität Göttingen, 37073, Göttingen, Germany
| | - Toru Miura
- Misaki Marine Biological Station, School of Science, The University of Tokyo, Misaki, Miura, Kanagawa, 238-0225, Japan.
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3
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Martí-Solans J, Børve A, Bump P, Hejnol A, Lynagh T. Peripheral and central employment of acid-sensing ion channels during early bilaterian evolution. eLife 2023; 12:81613. [PMID: 36821351 PMCID: PMC9949801 DOI: 10.7554/elife.81613] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 01/08/2023] [Indexed: 02/24/2023] Open
Abstract
Nervous systems are endowed with rapid chemosensation and intercellular signaling by ligand-gated ion channels (LGICs). While a complex, bilaterally symmetrical nervous system is a major innovation of bilaterian animals, the employment of specific LGICs during early bilaterian evolution is poorly understood. We therefore questioned bilaterian animals' employment of acid-sensing ion channels (ASICs), LGICs that mediate fast excitatory responses to decreases in extracellular pH in vertebrate neurons. Our phylogenetic analysis identified an earlier emergence of ASICs from the overarching DEG/ENaC (degenerin/epithelial sodium channel) superfamily than previously thought and suggests that ASICs were a bilaterian innovation. Our broad examination of ASIC gene expression and biophysical function in each major bilaterian lineage of Xenacoelomorpha, Protostomia, and Deuterostomia suggests that the earliest bilaterian ASICs were probably expressed in the periphery, before being incorporated into the brain as it emerged independently in certain deuterostomes and xenacoelomorphs. The loss of certain peripheral cells from Ecdysozoa after they separated from other protostomes likely explains their loss of ASICs, and thus the absence of ASICs from model organisms Drosophila and Caenorhabditis elegans. Thus, our use of diverse bilaterians in the investigation of LGIC expression and function offers a unique hypothesis on the employment of LGICs in early bilaterian evolution.
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Affiliation(s)
| | - Aina Børve
- Department of Biological Sciences, University of BergenBergenNorway
| | - Paul Bump
- Hopkins Marine Station, Department of Biology, Stanford UniversityPacific GroveUnited States
| | - Andreas Hejnol
- Department of Biological Sciences, University of BergenBergenNorway
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Srivastava M. Studying development, regeneration, stem cells, and more in the acoel Hofstenia miamia. Curr Top Dev Biol 2022; 147:153-172. [PMID: 35337448 DOI: 10.1016/bs.ctdb.2022.01.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Acoel worms represent an enigmatic lineage of animals (Acoelomorpha) that has danced around the tree of animal life. Morphology-based classification placed them as flatworms (Phylum Platyhelminthes), with much of their biology being interpreted as a variation on what is observed in better-studied members of that phylum. However, molecular phylogenies suggest that acoels belong to a clade (Xenacoelomorpha) that could be a sister group to other animals with bilateral symmetry (Bilateria) or could belong within deuterostomes, closely related to a group that includes sea stars (Ambulacraria). This change in phylogenetic position has led to renewed interest in the biology of acoels, which can now offer insights into the evolution of many bilaterian traits. The acoel Hofstenia miamia has emerged as a powerful new research organism that enables mechanistic studies of xenacoelomorph biology, especially of developmental and regenerative processes. This article explains the motivation for developing Hofstenia as a new model system, describes Hofstenia biology, highlights the tools and resources that make Hofstenia a good research organism, and considers the questions that Hofstenia is well-positioned to answer. Finally, looking to the future, this article serves as an invitation to new and established scientists to join the growing community of researchers studying this exciting model system.
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Affiliation(s)
- Mansi Srivastava
- Department of Organismic and Evolutionary Biology, Museum of Comparative Zoology, Harvard University, Cambridge, MA, United States.
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5
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Asai M, Miyazawa H, Yanase R, Inaba K, Nakano H. A New Species of Acoela Possessing a Middorsal Appendage with a Possible Sensory Function. Zoolog Sci 2022; 39:147-156. [DOI: 10.2108/zs210058] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 11/03/2021] [Indexed: 11/17/2022]
Affiliation(s)
- Masashi Asai
- Shimoda Marine Research Center, University of Tsukuba, 5-10-1, Shimoda, Shizuoka, 415-0025, Japan
| | - Hideyuki Miyazawa
- Shimoda Marine Research Center, University of Tsukuba, 5-10-1, Shimoda, Shizuoka, 415-0025, Japan
| | - Ryuji Yanase
- Shimoda Marine Research Center, University of Tsukuba, 5-10-1, Shimoda, Shizuoka, 415-0025, Japan
| | - Kazuo Inaba
- Shimoda Marine Research Center, University of Tsukuba, 5-10-1, Shimoda, Shizuoka, 415-0025, Japan
| | - Hiroaki Nakano
- Shimoda Marine Research Center, University of Tsukuba, 5-10-1, Shimoda, Shizuoka, 415-0025, Japan
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Goel T, Ireland D, Shetty V, Rabeler C, Diamond PH, Collins EMS. Let it rip: the mechanics of self-bisection in asexual planarians determines their population reproductive strategies. Phys Biol 2021; 19. [PMID: 34638110 DOI: 10.1088/1478-3975/ac2f29] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 10/12/2021] [Indexed: 11/11/2022]
Abstract
Asexual freshwater planarians reproduce by transverse bisection (binary fission) into two pieces. This process produces a head and a tail, which fully regenerate within 1-2 weeks. How planarians split into two offspring-using only their musculature and substrate traction-is a challenging biomechanics problem. We found that three different species,Dugesia japonica,Girardia tigrinaandSchmidtea mediterranea, have evolved three different mechanical solutions to self-bisect. Using time lapse imaging of the fission process, we quantitatively characterize the main steps of division in the three species and extract the distinct and shared key features. Across the three species, planarians actively alter their body shape, regulate substrate traction, and use their muscles to generate tensile stresses large enough to overcome the ultimate tensile strength of the tissue. Moreover, we show thathoweach planarian species divides dictates how resources are split among its offspring. This ultimately determines offspring survival and reproductive success. Thus, heterospecific differences in the mechanics of self-bisection of individual worms explain the observed differences in the population reproductive strategies of different planarian species.
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Affiliation(s)
- Tapan Goel
- Physics Department, UC San Diego, La Jolla, CA, United States of America
| | - Danielle Ireland
- Biology Department, Swarthmore College, Swarthmore, PA, United States of America
| | - Vir Shetty
- Physics and Astronomy Department, Swarthmore College, Swarthmore, PA, United States of America
| | - Christina Rabeler
- Biology Department, Swarthmore College, Swarthmore, PA, United States of America
| | - Patrick H Diamond
- Physics Department, UC San Diego, La Jolla, CA, United States of America
| | - Eva-Maria S Collins
- Physics Department, UC San Diego, La Jolla, CA, United States of America.,Biology Department, Swarthmore College, Swarthmore, PA, United States of America.,Physics and Astronomy Department, Swarthmore College, Swarthmore, PA, United States of America
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7
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Ultrastructure of spermatozoa and female copulatory organs in preferably asexually-reproducing acoel Convolutriloba retrogemma (Acoelomorpha). ZOOMORPHOLOGY 2020. [DOI: 10.1007/s00435-020-00505-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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8
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Gavilán B, Sprecher SG, Hartenstein V, Martinez P. The digestive system of xenacoelomorphs. Cell Tissue Res 2019; 377:369-382. [PMID: 31093756 DOI: 10.1007/s00441-019-03038-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 04/16/2019] [Indexed: 11/26/2022]
Abstract
Interest in the study of Xenacoelomorpha has recently been revived due to realization of its key phylogenetic position as the putative sister group of the remaining Bilateria. Phylogenomic studies have attracted the attention of researchers interested in the evolution of animals and the origin of novelties. However, it is clear that a proper understanding of novelties can only be gained in the context of thorough descriptions of the anatomy of the different members of this phylum. A considerable literature, based mainly on conventional histological techniques, describes different aspects of xenacoelomorphs' tissue architecture. However, the focus has been somewhat uneven; some tissues, such as the neuro-muscular system, are relatively well described in most groups, whereas others, including the digestive system, are only poorly understood. Our lack of knowledge of the xenacoelomorph digestive system is exacerbated by the assumption that, at least in Acoela, which possess a syncytial gut, the digestive system is a derived and specialized tissue with little bearing on what is observed in other bilaterian animals. Here, we try to remedy this lack of attention by revisiting the different studies of the xenacoelomorph digestive system, and we discuss the diversity present in the light of new evolutionary knowledge.
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Affiliation(s)
- B Gavilán
- Departament de Genètica, Microbiologia i Estadística, Universitat de Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain
| | - S G Sprecher
- Department of Biology, University of Fribourg, 10, ch. Du Musée, 1700, Fribourg, Switzerland
| | - V Hartenstein
- Department of Biology, University of California, Los Angeles, CA, USA.
| | - P Martinez
- Departament de Genètica, Microbiologia i Estadística, Universitat de Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain.
- Institut Català de Recerca i Estudis Avançats (ICREA), Barcelona, Spain.
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9
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Dittmann IL, Zauchner T, Nevard LM, Telford MJ, Egger B. SALMFamide2 and serotonin immunoreactivity in the nervous system of some acoels (Xenacoelomorpha). J Morphol 2018; 279:589-597. [PMID: 29388261 PMCID: PMC5947262 DOI: 10.1002/jmor.20794] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 12/20/2017] [Accepted: 12/31/2017] [Indexed: 11/06/2022]
Abstract
Acoel worms are simple, often microscopic animals with direct development, a multiciliated epidermis, a statocyst, and a digestive parenchyma instead of a gut epithelium. Morphological characters of acoels have been notoriously difficult to interpret due to their relative scarcity. The nervous system is one of the most accessible and widely used comparative features in acoels, which have a so-called commissural brain without capsule and several major longitudinal neurite bundles. Here, we use the selective binding properties of a neuropeptide antibody raised in echinoderms (SALMFamide2, or S2), and a commercial antibody against serotonin (5-HT) to provide additional characters of the acoel nervous system. We have prepared whole-mount immunofluorescent stainings of three acoel species: Symsagittifera psammophila (Convolutidae), Aphanostoma pisae, and the model acoel Isodiametra pulchra (both Isodiametridae). The commissural brain of all three acoels is delimited anteriorly by the ventral anterior commissure, and posteriorly by the dorsal posterior commissure. The dorsal anterior commissure is situated between the ventral anterior commissure and the dorsal posterior commissure, while the statocyst lies between dorsal anterior and dorsal posterior commissure. S2 and serotonin do not co-localise, and they follow similar patterns to each other within an animal. In particular, S2, but not 5-HT, stains a prominent commissure posterior to the main (dorsal) posterior commissure. We have for the first time observed a closed posterior loop of the main neurite bundles in S. psammophila for both the amidergic and the serotonergic nervous system. In I. pulchra, the lateral neurite bundles also form a posterior loop in our serotonergic nervous system stainings.
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Affiliation(s)
- Isabel L. Dittmann
- Research unit Evolutionary Developmental BiologyInstitute of Zoology, University of Innsbruck, Technikerstr. 25Innsbruck6020Austria
| | - Thomas Zauchner
- Research unit Evolutionary Developmental BiologyInstitute of Zoology, University of Innsbruck, Technikerstr. 25Innsbruck6020Austria
- Department of Genetics, Evolution and EnvironmentUniversity College London, Darwin Building, Gower StreetLondonWC1E 6BTUnited Kingdom
| | - Lucy M. Nevard
- Department of Genetics, Evolution and EnvironmentUniversity College London, Darwin Building, Gower StreetLondonWC1E 6BTUnited Kingdom
| | - Maximilian J. Telford
- Department of Genetics, Evolution and EnvironmentUniversity College London, Darwin Building, Gower StreetLondonWC1E 6BTUnited Kingdom
| | - Bernhard Egger
- Research unit Evolutionary Developmental BiologyInstitute of Zoology, University of Innsbruck, Technikerstr. 25Innsbruck6020Austria
- Department of Genetics, Evolution and EnvironmentUniversity College London, Darwin Building, Gower StreetLondonWC1E 6BTUnited Kingdom
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Abstract
Because of their sessile lifestyle and the lack of the sensory and feeding structures usually associated with the cephalic end, fixing the antero-posterior (AP) polarity of tapeworms is somewhat equivocal and has been a matter of century-long debates. Koziol et al. offer the first molecular evidence finally fixing the scolex as the animal’s anterior pole.
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Affiliation(s)
- Alessandro Minelli
- Department of Biology, University of Padova, Via Ugo Bassi 58 B, I 35131, Padova, Italy.
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11
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Haszprunar G. Review of data for a morphological look on Xenacoelomorpha (Bilateria incertae sedis). ORG DIVERS EVOL 2015. [DOI: 10.1007/s13127-015-0249-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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12
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Petralia RS, Mattson MP, Yao PJ. Aging and longevity in the simplest animals and the quest for immortality. Ageing Res Rev 2014; 16:66-82. [PMID: 24910306 DOI: 10.1016/j.arr.2014.05.003] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Revised: 05/08/2014] [Accepted: 05/22/2014] [Indexed: 12/12/2022]
Abstract
Here we review the examples of great longevity and potential immortality in the earliest animal types and contrast and compare these to humans and other higher animals. We start by discussing aging in single-celled organisms such as yeast and ciliates, and the idea of the immortal cell clone. Then we describe how these cell clones could become organized into colonies of different cell types that lead to multicellular animal life. We survey aging and longevity in all of the basal metazoan groups including ctenophores (comb jellies), sponges, placozoans, cnidarians (hydras, jellyfish, corals and sea anemones) and myxozoans. Then we move to the simplest bilaterian animals (with a head, three body cell layers, and bilateral symmetry), the two phyla of flatworms. A key determinant of longevity and immortality in most of these simple animals is the large numbers of pluripotent stem cells that underlie the remarkable abilities of these animals to regenerate and rejuvenate themselves. Finally, we discuss briefly the evolution of the higher bilaterians and how longevity was reduced and immortality lost due to attainment of greater body complexity and cell cycle strategies that protect these complex organisms from developing tumors. We also briefly consider how the evolution of multiple aging-related mechanisms/pathways hinders our ability to understand and modify the aging process in higher organisms.
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Fischer AHL, Mozzherin D, Eren AM, Lans KD, Wilson N, Cosentino C, Smith J. SeaBase: a multispecies transcriptomic resource and platform for gene network inference. Integr Comp Biol 2014; 54:250-63. [PMID: 24907201 DOI: 10.1093/icb/icu065] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Marine and aquatic animals are extraordinarily useful as models for identifying mechanisms of development and evolution, regeneration, resistance to cancer, longevity and symbiosis, among many other areas of research. This is due to the great diversity of these organisms and their wide-ranging capabilities. Genomics tools are essential for taking advantage of these "free lessons" of nature. However, genomics and transcriptomics are challenging in emerging model systems. Here, we present SeaBase, a tool for helping to meet these needs. Specifically, SeaBase provides a platform for sharing and searching transcriptome data. More importantly, SeaBase will support a growing number of tools for inferring gene network mechanisms. The first dataset available on SeaBase is a developmental transcriptomic profile of the sea anemone Nematostella vectensis (Anthozoa, Cnidaria). Additional datasets are currently being prepared and we are aiming to expand SeaBase to include user-supplied data for any number of marine and aquatic organisms, thereby supporting many potentially new models for gene network studies. SeaBase can be accessed online at: http://seabase.core.cli.mbl.edu.
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Affiliation(s)
- Antje H L Fischer
- *Marine Biological Laboratory, Woods Hole, MA 02543, USA; Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA; Systems & Control Engineering, University of Magna Graecia, 88100 Catanzaro, Italy*Marine Biological Laboratory, Woods Hole, MA 02543, USA; Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA; Systems & Control Engineering, University of Magna Graecia, 88100 Catanzaro, Italy
| | - Dmitry Mozzherin
- *Marine Biological Laboratory, Woods Hole, MA 02543, USA; Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA; Systems & Control Engineering, University of Magna Graecia, 88100 Catanzaro, Italy
| | - A Murat Eren
- *Marine Biological Laboratory, Woods Hole, MA 02543, USA; Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA; Systems & Control Engineering, University of Magna Graecia, 88100 Catanzaro, Italy
| | - Kristen D Lans
- *Marine Biological Laboratory, Woods Hole, MA 02543, USA; Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA; Systems & Control Engineering, University of Magna Graecia, 88100 Catanzaro, Italy
| | - Nathan Wilson
- *Marine Biological Laboratory, Woods Hole, MA 02543, USA; Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA; Systems & Control Engineering, University of Magna Graecia, 88100 Catanzaro, Italy
| | - Carlo Cosentino
- *Marine Biological Laboratory, Woods Hole, MA 02543, USA; Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA; Systems & Control Engineering, University of Magna Graecia, 88100 Catanzaro, Italy
| | - Joel Smith
- *Marine Biological Laboratory, Woods Hole, MA 02543, USA; Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA; Systems & Control Engineering, University of Magna Graecia, 88100 Catanzaro, Italy
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14
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Perea-Atienza E, Botta M, Salvenmoser W, Gschwentner R, Egger B, Kristof A, Martinez P, Achatz JG. Posterior regeneration in Isodiametra pulchra (Acoela, Acoelomorpha). Front Zool 2013; 10:64. [PMID: 24160844 PMCID: PMC3816570 DOI: 10.1186/1742-9994-10-64] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 10/17/2013] [Indexed: 01/30/2023] Open
Abstract
INTRODUCTION Regeneration is a widespread phenomenon in the animal kingdom, but the capacity to restore damaged or missing tissue varies greatly between different phyla and even within the same phylum. However, the distantly related Acoelomorpha and Platyhelminthes share a strikingly similar stem-cell system and regenerative capacity. Therefore, comparing the underlying mechanisms in these two phyla paves the way for an increased understanding of the evolution of this developmental process.To date, Isodiametra pulchra is the most promising candidate as a model for the Acoelomorpha, as it reproduces steadily under laboratory conditions and is amenable to various techniques, including the silencing of gene expression by RNAi. In order to provide an essential framework for future studies, we report the succession of regeneration events via the use of cytochemical, histological and microscopy techniques, and specify the total number of cells in adult individuals. RESULTS Isodiametra pulchra is not capable of regenerating a new head, but completely restores all posterior structures within 10 days. Following amputation, the wound closes via the contraction of local muscle fibres and an extension of the dorsal epidermis. Subsequently, stem cells and differentiating cells invade the wound area and form a loosely delimited blastema. After two days, the posterior end is re-patterned with the male (and occasionally the female) genital primordium being apparent. Successively, these primordia differentiate into complete copulatory organs. The size of the body and also of the male and female copulatory organs, as well as the distance between the copulatory organs, progressively increase and by nine days copulation is possible. Adult individuals with an average length of 670 μm consist of approximately 8100 cells. CONCLUSION Isodiametra pulchra regenerates through a combination of morphallactic and epimorphic processes. Existing structures are "re-modelled" and provide a framework onto which newly differentiating cells are added. Growth proceeds through the intercalary addition of structures, mirroring the embryonic and post-embryonic development of various organ systems. The suitability of Isodiametra pulchra for laboratory techniques, the fact that its transcriptome and genome data will soon be available, as well as its small size and low number of cells, make it a prime candidate subject for research into the cellular mechanisms that underlie regeneration in acoelomorphs.
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Affiliation(s)
- Elena Perea-Atienza
- Department of Genetics, University of Barcelona, Av. Diagonal 643, edifici annex, planta 2a, 08028 Barcelona, Spain
| | - Maria Botta
- Department of Evolutionary Developmental Biology, University of Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria
| | - Willi Salvenmoser
- Department of Evolutionary Developmental Biology, University of Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria
| | - Robert Gschwentner
- Department of Evolutionary Developmental Biology, University of Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria
| | - Bernhard Egger
- Department of Evolutionary Developmental Biology, University of Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria
- Department of Genetics, Evolution and Environment, University College London, Darwin Building, Gower Street, London WC1E 6BT, UK
| | - Alen Kristof
- Department of Integrative Zoology, University of Vienna, Althanstrasse 14, UZA 1, 1090 Vienna, Austria
| | - Pedro Martinez
- Department of Genetics, University of Barcelona, Av. Diagonal 643, edifici annex, planta 2a, 08028 Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig Lluís Companys 23, 08010 Barcelona, Spain
| | - Johannes Georg Achatz
- Department of Genetics, University of Barcelona, Av. Diagonal 643, edifici annex, planta 2a, 08028 Barcelona, Spain
- Department of Evolutionary Developmental Biology, University of Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria
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Abstract
Invertebrates comprise approximately 34 phyla, while vertebrates represent one subphylum and insects a (very large) class. Thus, the clades excepting vertebrates and insects encompass almost all of animal diversity. Consequently, the barcoding challenge in invertebrates is that of barcoding animals in general. While standard extraction, cleaning, PCR methods, and universal primers work for many taxa, taxon-specific challenges arise because of the shear genetic and biochemical diversity present across the kingdom, and because problems arising as a result of this diversity, and solutions to them, are still poorly characterized for many metazoan clades. The objective of this chapter is to emphasize general approaches, and give practical advice for overcoming the diverse challenges that may be encountered across animal taxa, but we stop short of providing an exhaustive inventory. Rather, we encourage researchers, especially those working on poorly studied taxa, to carefully consider methodological issues presented below, when standard approaches perform poorly.
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Affiliation(s)
- Nathaniel Evans
- Florida Museum of Natural History, University of Florida, Gainesville, FL, USA
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Achatz JG, Martinez P. The nervous system of Isodiametra pulchra (Acoela) with a discussion on the neuroanatomy of the Xenacoelomorpha and its evolutionary implications. Front Zool 2012; 9:27. [PMID: 23072457 PMCID: PMC3488495 DOI: 10.1186/1742-9994-9-27] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Accepted: 10/09/2012] [Indexed: 12/21/2022] Open
Abstract
Introduction Acoels are microscopic marine worms that have become the focus of renewed debate and research due to their placement at the base of the Bilateria by molecular phylogenies. To date, Isodiametra pulchra is the most promising “model acoel” as it can be cultured and gene knockdown can be performed with double-stranded RNA. Despite its well-known morphology data on the nervous system are scarce. Therefore we examined this organ using various microscopic techniques, including histology, conventional histochemistry, electron microscopy, and immunocytochemistry in combination with CLSM and discuss our results in light of recently established phylogenies. Results The nervous system of Isodiametra pulchra consists of a bilobed brain with a dorsal posterior commissure, a frontal ring and tracts, four pairs of longitudinal neurite bundles, as well as a supramuscular and submuscular plexus. Serotonin-like immunoreactivity (SLI) is displayed in parts of the brain, the longitudinal neurite bundles and a large part of the supramuscular plexus, while FMRFamide-like immunoreactivity (RFLI) is displayed in parts of the brain and a distinct set of neurons, the longitudinal neurite bundles and the submuscular plexus. Despite this overlap SLI and RFLI are never colocalized. Most remarkable though is the presence of a distinct functional neuro-muscular system consisting of the statocyst, tracts, motor neurons and inner muscles, as well as the presence of various muscles that differ with regard to their ultrastructure and innervation. Conclusions The nervous system of Isodiametra pulchra consists of an insunk, bilobed brain, a peripheral part for perception and innervation of the smooth body-wall musculature as well as tracts and motor neurons that together with pseudostriated inner muscles are responsible for steering and quick movements. The insunk, bilobed brains with two to three commissures found in numerous acoels are homologous and evolved from a ring-commissural brain that was present in the stem species of acoelomorphs. The acoelomorph brain is bipartite, consisting of a Six3/6-dependend animal pole nervous system that persists throughout adulthood and an axial nervous system that does not develop by exhibiting a staggered pattern of conserved regulatory genes as in other bilaterians but by a nested pattern of these genes. This indicates that acoelomorphs stem from an ancestor with a simple brain or with a biphasic life cycle.
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Affiliation(s)
- Johannes Georg Achatz
- Department of Evolutionary Developmental Biology, University of Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria.
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Achatz JG, Chiodin M, Salvenmoser W, Tyler S, Martinez P. The Acoela: on their kind and kinships, especially with nemertodermatids and xenoturbellids (Bilateria incertae sedis). ORG DIVERS EVOL 2012; 13:267-286. [PMID: 24098090 PMCID: PMC3789126 DOI: 10.1007/s13127-012-0112-4] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Acoels are among the simplest worms and therefore have often been pivotal in discussions of the origin of the Bilateria. Initially thought primitive because of their “planula-like” morphology, including their lumenless digestive system, they were subsequently dismissed by many morphologists as a specialized clade of the Platyhelminthes. However, since molecular phylogenies placed them outside the Platyhelminthes and outside all other phyla at the base of the Bilateria, they became the focus of renewed debate and research. We review what is currently known of acoels, including information regarding their morphology, development, systematics, and phylogenetic relationships, and put some of these topics in a historical perspective to show how the application of new methods contributed to the progress in understanding these animals. Taking all available data into consideration, clear-cut conclusions cannot be made; however, in our view it becomes successively clearer that acoelomorphs are a “basal” but “divergent” branch of the Bilateria.
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Affiliation(s)
- Johannes G. Achatz
- Department of Genetics, University of Barcelona, Av. Diagonal, edifici annex, planta 2a, 08028 Barcelona, Spain
- Department of Evolutionary Developmental Biology, University of Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria
| | - Marta Chiodin
- Department of Genetics, University of Barcelona, Av. Diagonal, edifici annex, planta 2a, 08028 Barcelona, Spain
| | - Willi Salvenmoser
- Department of Evolutionary Developmental Biology, University of Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria
| | - Seth Tyler
- School of Biology and Ecology, University of Maine, 5751 Murray Hall, Orono, ME 04469 USA
| | - Pedro Martinez
- Department of Genetics, University of Barcelona, Av. Diagonal, edifici annex, planta 2a, 08028 Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig Lluís Companys, 23, 08010 Barcelona, Spain
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Thomas MA, Schötz EM. SAPling: a Scan-Add-Print barcoding database system to label and track asexual organisms. ACTA ACUST UNITED AC 2012; 214:3518-23. [PMID: 21993779 DOI: 10.1242/jeb.059048] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We have developed a 'Scan-Add-Print' database system, SAPling, to track and monitor asexually reproducing organisms. Using barcodes to uniquely identify each animal, we can record information on the life of the individual in a computerized database containing its entire family tree. SAPling has enabled us to carry out large-scale population dynamics experiments with thousands of planarians and keep track of each individual. The database stores information such as family connections, birth date, division date and generation. We show that SAPling can be easily adapted to other asexually reproducing organisms and has a strong potential for use in large-scale and/or long-term population and senescence studies as well as studies of clonal diversity. The software is platform-independent, designed for reliability and ease of use, and provided open source from our webpage to allow project-specific customization.
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Affiliation(s)
- Michael A Thomas
- 170 Carl Icahn Laboratory, Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
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CHIODIN MARTA, ACHATZ JOHANNESG, WANNINGER ANDREAS, MARTINEZ PEDRO. Molecular architecture of muscles in an acoel and its evolutionary implications. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART B, MOLECULAR AND DEVELOPMENTAL EVOLUTION 2011; 316:427-39. [PMID: 21538843 PMCID: PMC3501712 DOI: 10.1002/jez.b.21416] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2010] [Revised: 03/12/2011] [Accepted: 04/01/2011] [Indexed: 12/14/2022]
Abstract
We have characterized the homologs of an actin, a troponin I, and a tropomyosin gene in the acoel Symsagittifera roscoffensis. These genes are expressed in muscles and most likely coexpressed in at least a subset of them. In addition, and for the first time for Acoela, we have produced a species-specific muscular marker, an antibody against the tropomyosin protein. We have followed tropomyosin gene and protein expression during postembryonic development and during the posterior regeneration of amputated adults, showing that preexisting muscle fibers contribute to the wound closure. The three genes characterized in this study interact in the striated muscles of vertebrates and invertebrates, where troponin I and tropomyosin are key regulators of the contraction of the sarcomere. S. roscoffensis and all other acoels so far described have only smooth muscles, but the molecular architecture of these is the same as that of striated fibers of other bilaterians. Given the proposed basal position of acoels within the Bilateria, we suggest that sarcomeric muscles arose from a smooth muscle type, which had the molecular repertoire of striated musculature already in place. We discuss this model in a broad comparative perspective.
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Affiliation(s)
- MARTA CHIODIN
- Departament de Genètica, Universitat de Barcelona, Barcelona, Spain
| | | | - ANDREAS WANNINGER
- Department of Evolutionary Biology, Section of Morphology, University of Vienna, Vienna, Austria
| | - PEDRO MARTINEZ
- Departament de Genètica, Universitat de Barcelona, Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig Lluís Companys, Barcelona, Spain
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Making heads from tails: Development of a reversed anterior–posterior axis during budding in an acoel. Dev Biol 2010; 338:86-97. [DOI: 10.1016/j.ydbio.2009.10.033] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2009] [Revised: 10/21/2009] [Accepted: 10/21/2009] [Indexed: 11/23/2022]
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De Mulder K, Kuales G, Pfister D, Willems M, Egger B, Salvenmoser W, Thaler M, Gorny AK, Hrouda M, Borgonie G, Ladurner P. Characterization of the stem cell system of the acoel Isodiametra pulchra. BMC DEVELOPMENTAL BIOLOGY 2009; 9:69. [PMID: 20017953 PMCID: PMC2806412 DOI: 10.1186/1471-213x-9-69] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2009] [Accepted: 12/18/2009] [Indexed: 12/27/2022]
Abstract
Background Tissue plasticity and a substantial regeneration capacity based on stem cells are the hallmark of several invertebrate groups such as sponges, cnidarians and Platyhelminthes. Traditionally, Acoela were seen as an early branching clade within the Platyhelminthes, but became recently positioned at the base of the Bilateria. However, little is known on how the stem cell system in this new phylum is organized. In this study, we wanted to examine if Acoela possess a neoblast-like stem cell system that is responsible for development, growth, homeostasis and regeneration. Results We established enduring laboratory cultures of the acoel Isodiametra pulchra (Acoela, Acoelomorpha) and implemented in situ hybridization and RNA interference (RNAi) for this species. We used BrdU labelling, morphology, ultrastructure and molecular tools to illuminate the morphology, distribution and plasticity of acoel stem cells under different developmental conditions. We demonstrate that neoblasts are the only proliferating cells which are solely mesodermally located within the organism. By means of in situ hybridisation and protein localisation we could demonstrate that the piwi-like gene ipiwi1 is expressed in testes, ovaries as well as in a subpopulation of somatic stem cells. In addition, we show that germ cell progenitors are present in freshly hatched worms, suggesting an embryonic formation of the germline. We identified a potent stem cell system that is responsible for development, homeostasis, regeneration and regrowth upon starvation. Conclusions We introduce the acoel Isodiametra pulchra as potential new model organism, suitable to address developmental questions in this understudied phylum. We show that neoblasts in I. pulchra are crucial for tissue homeostasis, development and regeneration. Notably, epidermal cells were found to be renewed exclusively from parenchymally located stem cells, a situation known only from rhabditophoran flatworms so far. For further comparison, it will be important to analyse the stem cell systems of other key-positioned understudied taxa.
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Affiliation(s)
- Katrien De Mulder
- University of Innsbruck, Institute of Zoology, Technikerstrasse 25, A-6020 Innsbruck, Austria.
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