12
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Histological study on maturation, fertilization and the state of gonadal region following spawning in the model sea anemone, Nematostella vectensis

      research-article
      , , , *
      PLoS ONE
      Public Library of Science

      Read this article at

      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          The starlet sea-anemone Nematostella vectensis has emerged as a model organism in developmental biology. Still, our understanding of various biological features, including reproductive biology of this model species are in its infancy. Consequently, through histological sections, we study here key stages of the oogenesis (oocyte maturation/fertilization), as the state of the gonad region immediately after natural spawning. Germ cells develop in a secluded mesenterial gastrodermal zone, where the developing oocytes are surrounded by mucoid glandular cells and trophocytes (accessory cells). During vitellogenesis, the germinal vesicle in oocytes migrates towards the animal pole and the large polarized oocytes begin to mature, characterized by karyosphere formation. Then, the karyosphere breaks down, the chromosomes form the metaphase plate I and the eggs are extruded from the animal enclosed in a sticky, jelly-like mucoid mass, along with numerous nematosomes. Fertilization occurs externally at metaphase II via swimming sperm extruded by males during natural spawning. The polar bodies are ejected from the eggs and are situated within a narrow space between the egg’s vitelline membrane and the adjacent edge of the jelly coat. The cortical reaction occurs only at the polar bodies’ ejection site. Several spermatozoa can penetrate the same egg. Fertilization is accompanied by a strong ooplasmatic segregation. Immediately after spawning, the gonad region holds many previtellogenic and vitellogenic oocytes, though no oocytes with karyosphere. Above are the first histological descriptions for egg maturation, meiotic chromosome’s status at fertilization, fertilization and the gonadal region’s state following spawning, also documenting for the first time the ejection of the polar body.

          Related collections

          Most cited references72

          • Record: found
          • Abstract: found
          • Article: not found

          Sea anemone genome reveals ancestral eumetazoan gene repertoire and genomic organization.

          Sea anemones are seemingly primitive animals that, along with corals, jellyfish, and hydras, constitute the oldest eumetazoan phylum, the Cnidaria. Here, we report a comparative analysis of the draft genome of an emerging cnidarian model, the starlet sea anemone Nematostella vectensis. The sea anemone genome is complex, with a gene repertoire, exon-intron structure, and large-scale gene linkage more similar to vertebrates than to flies or nematodes, implying that the genome of the eumetazoan ancestor was similarly complex. Nearly one-fifth of the inferred genes of the ancestor are eumetazoan novelties, which are enriched for animal functions like cell signaling, adhesion, and synaptic transmission. Analysis of diverse pathways suggests that these gene "inventions" along the lineage leading to animals were likely already well integrated with preexisting eukaryotic genes in the eumetazoan progenitor.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            Investigating the origins of triploblasty: 'mesodermal' gene expression in a diploblastic animal, the sea anemone Nematostella vectensis (phylum, Cnidaria; class, Anthozoa).

            Mesoderm played a crucial role in the radiation of the triploblastic Bilateria, permitting the evolution of larger and more complex body plans than in the diploblastic, non-bilaterian animals. The sea anemone Nematostella is a non-bilaterian animal, a member of the phylum Cnidaria. The phylum Cnidaria (sea anemones, corals, hydras and jellyfish) is the likely sister group of the triploblastic Bilateria. Cnidarians are generally regarded as diploblastic animals, possessing endoderm and ectoderm, but lacking mesoderm. To investigate the origin of triploblasty, we studied the developmental expression of seven genes from Nematostella whose bilaterian homologs are implicated in mesodermal specification and the differentiation of mesodermal cell types (twist, snailA, snailB, forkhead, mef2, a GATA transcription factor and a LIM transcription factor). Except for mef2, the expression of these genes is largely restricted to the endodermal layer, the gastrodermis. mef2 is restricted to the ectoderm. The temporal and spatial expression of these 'mesoderm' genes suggests that they may play a role in germ layer specification. Furthermore, the predominantly endodermal expression of these genes reinforces the hypothesis that the mesoderm and endoderm of triploblastic animals could be derived from the endoderm of a diploblastic ancestor. Alternatively, we consider the possibility that the diploblastic condition of cnidarians is a secondary simplification, derived from an ancestral condition of triploblasty.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              Origins of bilateral symmetry: Hox and dpp expression in a sea anemone.

              Over 99% of modern animals are members of the evolutionary lineage Bilateria. The evolutionary success of Bilateria is credited partly to the origin of bilateral symmetry. Although animals of the phylum Cnidaria are not within the Bilateria, some representatives, such as the sea anemone Nematostella vectensis, exhibit bilateral symmetry. We show that Nematostella uses homologous genes to achieve bilateral symmetry: Multiple Hox genes are expressed in a staggered fashion along its primary body axis, and the transforming growth factor-beta gene decapentaplegic (dpp) is expressed in an asymmetric fashion about its secondary body axis. These data suggest that bilateral symmetry arose before the evolutionary split of Cnidaria and Bilateria.
                Bookmark

                Author and article information

                Contributors
                Role: ConceptualizationRole: Data curationRole: Writing – original draftRole: Writing – review & editing
                Role: MethodologyRole: Writing – review & editing
                Role: Data curationRole: Writing – review & editing
                Role: Funding acquisitionRole: SupervisionRole: Writing – review & editing
                Role: Editor
                Journal
                PLoS One
                PLoS ONE
                plos
                plosone
                PLoS ONE
                Public Library of Science (San Francisco, CA USA )
                1932-6203
                10 August 2017
                2017
                : 12
                : 8
                : e0182677
                Affiliations
                [001]Israel Oceanography and Limnological Research, National Institute of Oceanography, Tel-Shikmona, Haifa, Israel
                University of California Irvine, UNITED STATES
                Author notes

                Competing Interests: The authors have declared that no competing interests exist.

                Author information
                http://orcid.org/0000-0003-2263-9019
                Article
                PONE-D-17-20110
                10.1371/journal.pone.0182677
                5552035
                28796817
                7b9e3017-2a56-464e-a1b5-3acce49bbb59
                © 2017 Moiseeva et al

                This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

                History
                : 25 May 2017
                : 22 July 2017
                Page count
                Figures: 6, Tables: 0, Pages: 17
                Funding
                Funded by: Ministry of National Infrastructures, Energy and Water Resources in Israel
                Award Recipient :
                This work was supported by the Ministry of National Infrastructures, Energy and Water Resources in Israel.
                Categories
                Research Article
                Biology and Life Sciences
                Cell Biology
                Cellular Types
                Animal Cells
                Germ Cells
                OVA
                Oocytes
                Biology and Life Sciences
                Developmental Biology
                Fertilization
                Biology and Life Sciences
                Cell Biology
                Cellular Types
                Animal Cells
                Germ Cells
                Sperm
                Biology and Life Sciences
                Developmental Biology
                Modes of Reproduction
                Sexual Reproduction
                Spawning
                Biology and Life Sciences
                Cell Biology
                Cellular Structures and Organelles
                Vesicles
                Biology and Life Sciences
                Cell Biology
                Cellular Types
                Animal Cells
                Germ Cells
                Biology and Life Sciences
                Anatomy
                Abdomen
                Peritoneum
                Mesentery
                Medicine and Health Sciences
                Anatomy
                Abdomen
                Peritoneum
                Mesentery
                Research and Analysis Methods
                Specimen Preparation and Treatment
                Staining
                Cell Staining
                Custom metadata
                All relevant data are within the paper.

                Uncategorized
                Uncategorized

                Comments

                Comment on this article