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Skalon EK, Starunov VV, Bondarenko NI, Slyusarev GS. Plasmodium structure of Intoshia linei (Orthonectida). J Morphol 2023; 284:e21602. [PMID: 37313769 DOI: 10.1002/jmor.21602] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 05/10/2023] [Accepted: 05/13/2023] [Indexed: 06/15/2023]
Abstract
Orthonectids are enigmatic parasitic bilaterians whose exact position on the phylogenetic tree is still uncertain. Despite ongoing debate about their phylogenetic position, the parasitic stage of orthonectids known as "plasmodium" remains underexplored. There is still no consensus on the origin of the plasmodium: whether it is an altered host cell or a parasitic organism that develops in the host extracellular environment. To determine the origin of the orthonectid parasitic stage, we studied in detail the fine structure of the Intoshia linei orthonectid plasmodium using a variety of morphological methods. The orthonectid plasmodium is a shapeless multinucleated organism separated from host tissues by a double membrane envelope. Besides numerous nuclei, its cytoplasm contains organelles typical for other bilaterians, reproductive cells, and maturing sexual specimens. Reproductive cells, as well as developing orthonectid males and females, are covered by an additional membrane. The plasmodium forms protrusions directed to the surface of the host body and used by mature individuals for egress from the host. The obtained results indicate that the orthonectid plasmodium is an extracellular parasite. A possible mechanism for its formation might involve spreading parasitic larva cells across the host tissues with subsequent generation of a cell-within-cell complex. The cytoplasm of the plasmodium originates from the outer cell, which undergoes multiple nuclear divisions without cytokinesis, while the inner cell divides, giving rise to reproductive cells and embryos. The term "plasmodium" should be avoided and the term "orthonectid plasmodium" could be temporarily used instead.
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Affiliation(s)
- Elizaveta K Skalon
- Department of Invertebrate Zoology, Faculty of Biology, St. Petersburg University, St. Petersburg, Russia
| | - Viktor V Starunov
- Department of Invertebrate Zoology, Faculty of Biology, St. Petersburg University, St. Petersburg, Russia
| | - Natalya I Bondarenko
- Department of Invertebrate Zoology, Faculty of Biology, St. Petersburg University, St. Petersburg, Russia
| | - George S Slyusarev
- Department of Invertebrate Zoology, Faculty of Biology, St. Petersburg University, St. Petersburg, Russia
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Liberman R, Benayahu Y, Huchon D. Octocorals in the Gulf of Aqaba exhibit high photosymbiont fidelity. Front Microbiol 2022; 13:1005471. [PMID: 36504779 PMCID: PMC9732034 DOI: 10.3389/fmicb.2022.1005471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 10/25/2022] [Indexed: 11/26/2022] Open
Abstract
Symbiotic associations, widespread in terrestrial and marine ecosystems, are of considerable ecological importance. Many tropical coral species are holobionts, formed by the obligate association between a cnidarian host and endosymbiotic dinoflagellates of the family Symbiodiniaceae. The latter are abundant on coral reefs from very shallow water down to the upper mesophotic zone (30-70 m). The research on scleractinians has revealed that the photosymbiont lineages present in the cnidarian host play an important role in the coral's ability to thrive under different environmental conditions, such as light regime and temperature. However, little is known regarding octocoral photosymbionts, and in particular regarding those found deeper than 30 m. Here, we used ribosomal (ITS2) and chloroplast (23S) markers to uncover, for the first time, the dominant Symbiodiniaceae taxa present in 19 mesophotic octocoral species (30-70 m depth) from the Gulf of Aqaba/Eilat (northern Red Sea). In addition, using high-throughput sequencing of the ITS2 region we characterized both the dominant and the rare Symbiodiniaceae lineages found in several species across depth. The phylogenetic analyses of both markers were in agreement and revealed that most of the studied mesophotic octocorals host the genus Cladocopium. Litophyton spp. and Klyxum utinomii were exceptions, as they harbored Symbiodinium and Durusdinium photosymbionts, respectively. While the dominant algal lineage of each coral species did not vary across depth, the endosymbiont community structure significantly differed between host species, as well as between different depths for some host species. The findings from this study contribute to the growing global-catalogue of Cnidaria-Symbiodiniaceae associations. Unravelling the Symbiodiniaceae composition in octocoral holobionts across environmental gradients, depth in particular, may enable a better understanding of how specialized those associations are, and to what extent coral holobionts are able to modify their photosymbionts.
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Affiliation(s)
- Ronen Liberman
- School of Zoology, The George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel Aviv, Israel,The Interuniversity Institute for Marine Sciences, Eilat, Israel,*Correspondence: Ronen Liberman,
| | - Yehuda Benayahu
- School of Zoology, The George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel Aviv, Israel
| | - Dorothée Huchon
- School of Zoology, The George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel Aviv, Israel,The Steinhardt Museum of Natural History and National Research Center, Tel Aviv University, Tel Aviv, Israel
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Williamson JE, Gillings MR, Nevatte RJ, Harasti D, Raoult V, Ghaly TM, Stow AJ, Smith TM, Gaston TF. Genetic differentiation in the threatened soft coral
Dendronephthya australis
in temperate eastern Australia. AUSTRAL ECOL 2022. [DOI: 10.1111/aec.13160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Jane E. Williamson
- School of Natural Sciences Macquarie University Sydney New South Wales Australia
| | - Michael R. Gillings
- School of Natural Sciences Macquarie University Sydney New South Wales Australia
| | - Ryan J. Nevatte
- School of Natural Sciences Macquarie University Sydney New South Wales Australia
| | - David Harasti
- Fisheries Research, NSW Department of Primary Industries Port Stephens Fisheries Institute Port Stephens New South Wales Australia
| | - Vincent Raoult
- School of Environmental and Life Sciences University of Newcastle Ourimbah New South Wales Australia
| | - Timothy M. Ghaly
- School of Natural Sciences Macquarie University Sydney New South Wales Australia
| | - Adam J. Stow
- School of Natural Sciences Macquarie University Sydney New South Wales Australia
| | - Timothy M. Smith
- School of Environmental and Life Sciences University of Newcastle Ourimbah New South Wales Australia
| | - Troy F. Gaston
- School of Environmental and Life Sciences University of Newcastle Ourimbah New South Wales Australia
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Gabay Y, Weis VM, Davy SK. Symbiont Identity Influences Patterns of Symbiosis Establishment, Host Growth, and Asexual Reproduction in a Model Cnidarian-Dinoflagellate Symbiosis. THE BIOLOGICAL BULLETIN 2018; 234:1-10. [PMID: 29694802 DOI: 10.1086/696365] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The genus Symbiodinium is physiologically diverse and so may differentially influence symbiosis establishment and function. To explore this, we inoculated aposymbiotic individuals of the sea anemone Exaiptasia pallida (commonly referred to as "Aiptasia"), a model for coral symbiosis, with one of five Symbiodinium species or types (S. microadriaticum, S. minutum, phylotype C3, S. trenchii, or S. voratum). The spatial pattern of colonization was monitored over time via confocal microscopy, and various physiological parameters were measured to assess symbiosis functionality. Anemones rapidly formed a symbiosis with the homologous symbiont, S. minutum, but struggled or failed to form a long-lasting symbiosis with Symbiodinium C3 or S. voratum, respectively. Symbiodinium microadriaticum and S. trenchii were successful but reached their peak density two weeks after S. minutum. The spatial pattern of colonization was identical for all Symbiodinium taxa that were ultimately successful, starting in the oral disk and progressing to the tentacles, before invading the column and, finally, the pedal disk. In all cases, proliferation through the anemone's tentacles was patchy, suggesting that symbionts were being expelled into the gastrovascular cavity and re-phagocytosed by the host. However, the timing of these various spatial events differed between the different Symbiodinium taxa. Furthermore, S. microadriaticum and S. trenchii were less beneficial to the host, as indicated by lower rates of photosynthesis, anemone growth, and pedal laceration. This study enhances our understanding of the link between symbiont identity and the performance of the overall symbiosis, which is important for understanding the potential establishment and persistence of novel host-symbiont pairings. Importantly, we also provide a baseline for further studies on this topic with the globally adopted "Aiptasia" model system.
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Mies M, Sumida PYG, Rädecker N, Voolstra CR. Marine Invertebrate Larvae Associated with Symbiodinium: A Mutualism from the Start? Front Ecol Evol 2017. [DOI: 10.3389/fevo.2017.00056] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Hikosaka-Katayama T, Koike K, Yamashita H, Hikosaka A, Koike K. Mechanisms of Maternal Inheritance of Dinoflagellate Symbionts in the Acoelomorph WormWaminoa litus. Zoolog Sci 2012; 29:559-67. [DOI: 10.2108/zsj.29.559] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Morris DJ. A new model for myxosporean (Myxozoa) development explains the endogenous budding phenomenon, the nature of cell within cell life stages and evolution of parasitism from a cnidarian ancestor. Int J Parasitol 2012; 42:829-40. [PMID: 22749958 DOI: 10.1016/j.ijpara.2012.06.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Revised: 06/05/2012] [Accepted: 06/06/2012] [Indexed: 11/17/2022]
Abstract
The phylum Myxozoa is composed of endoparasitic species that have predominately been recorded within aquatic vertebrates. The simple body form of a trophic cell containing other cells within it, as observed within these hosts, has provided few clues to relationships with other organisms. In addition, the placement of the group using molecular phylogenies has proved very difficult, although the majority of analyses now suggest that they are cnidarians. There have been relatively few studies of myxozoan stages within invertebrate hosts, even though these exhibit multicellular and sexual stages that may provide clues to myxozoan evolution. Therefore an ultrastructural examination of a myxozoan infection of a freshwater oligochaete was conducted, to reassess and formulate a model for myxozoan development in these hosts. This deemed that meiosis occurs within the oligochaete, but that fertilisation is not immediate. Rather, the resultant haploid germ cell (oocyte) is engulfed by a diploid sporogonic cell (nurse cell) to form a sporoplasm. It is this sporoplasm that infects the fish, resulting in the multicellular stages observed. Fertilisation occurs after the parasites leave the fish and enter the oligochaete host. The nurse cell/oocyte model explains previously conflicting evidence in the literature regarding myxosporean biology, and aligns phenomena considered distinctive to the Myxozoa, such as endogenous budding and cell within cell development, with processes recorded in cnidarians. Finally, the evolutionary origin of the Myxozoa as cnidarian parasites of ova is hypothesised.
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Affiliation(s)
- D J Morris
- Institute of Aquaculture, University of Stirling, Stirling, Scotland, UK.
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Abstract
Eukaryotes form new cells through the replication of nuclei followed by cytokinesis. A notable exception is reported from the class Myxosporea of the phylum Myxozoa. This assemblage of approximately 2310 species is regarded as either basal bilaterian or cnidarian, depending on the phylogenetic analysis employed. For myxosporeans, cells have long been regarded as forming within other cells by a process referred to as endogenous budding. This would involve a nucleus forming endoplasmic reticulum around it, which transforms into a new plasma membrane, thus enclosing and separating it from the surrounding cell. This remarkable process, unique within the Metazoa, is accepted as occurring within stages found in vertebrate hosts, but has only been inferred from those stages observed within invertebrate hosts. Therefore, I conducted an ultrastructural study to examine how internal cells are formed by a myxosporean parasitizing an annelid. In this case, actinospore parasite stages clearly internalized existing cells; a process with analogies to the acquisition of endosymbiotic algae by cnidarian species. A subsequent examination of the myxozoan literature did not support endogenous budding, indicating that this process, which has been a central tenet of myxozoan developmental biology for over a century, is dogma.
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Affiliation(s)
- David J Morris
- Institute of Aquaculture, University of Stirling, Stirling FK9 4LA, UK.
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Hirose M, Hidaka M. Early development of zooxanthella-containing eggs of the corals Porites cylindrica and Montipora digitata: The endodermal localization of zooxanthellae. Zoolog Sci 2007; 23:873-81. [PMID: 17116990 DOI: 10.2108/zsj.23.873] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We studied the early development of zooxanthellae-containing eggs of the scleractinian corals Porites cylindrica and Montipora digitata to elucidate how zooxanthellae become localized to the endoderm of planulae during the course of development. In both species, zooxanthellae were distributed evenly in the oocytes and delivered almost equally to the blastomeres during cleavage. In P. cylindrica, gastrulation occurred via delamination or ingression, and blastomeres containing zooxanthellae dropped into the blastocoel during gastrulation. Thus, zooxanthellae were restricted to the endodermal cells at the gastrula or early planula stage in P. cylindrica. In M. digitata, gastrulation occurred by a combination of invagination and epiboly to form a somewhat concave gastrula. Zooxanthellae were present in both endodermal and ectodermal cells of early planulae, but they disappeared from the ectoderm as the planulae matured. In our previous study on two species of Pocillopora, we found that zooxanthellae were localized in eggs as well as in embryos, and that blastomeres containing zooxanthellae later dropped into the blastocoel to become restricted to the endoderm (Hirose et al., 2000). The timing and mechanism of zooxanthella localization and types of gastrulation differed among species belonging to the three genera. These results suggest that zooxanthella localization in the embryos reflects the timing of the determination of presumptive endoderm cells and/or specificity of zooxanthellae toward presumptive endoderm cells.
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Affiliation(s)
- Mamiko Hirose
- Department of Chemistry, Biology and Marine Science, University of the Ryukyus, Nishihara, Okinawa, Japan.
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Davy SK, Turner JR. Early development and acquisition of Zooxanthellae in the temperate symbiotic sea anemone Anthopleura ballii (Cocks). THE BIOLOGICAL BULLETIN 2003; 205:66-72. [PMID: 12917223 DOI: 10.2307/1543446] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The ova of Anthopleura ballii become infected with zooxanthellae (endosymbiotic dinoflagellates) of maternal origin just prior to spawning. After fertilization, the zygotes undergo radial, holoblastic cleavage, and then gastrulate by invagination to form ciliated planulae. Because the zooxanthellae are localized on one side of the ovum-and later, within the blastomeres at one end of the embryo-invagination leads to the zooxanthellae being restricted to the planular endoderm and hence to the gastrodermal cells of the adult anemone. We propose that maternal inheritance of zooxanthellae plays an important part in the success of these temperate sea anemones, which live in regions where potential sources of zooxanthellae are scarce.
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Affiliation(s)
- Simon K Davy
- Institute of Marine Studies, University of Plymouth, Drake Circus, Plymouth PL4 8AA, UK
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Jimbo M, Yanohara T, Koike K, Koike K, Sakai R, Muramoto K, Kamiya H. The D-galactose-binding lectin of the octocoral Sinularia lochmodes: characterization and possible relationship to the symbiotic dinoflagellates. Comp Biochem Physiol B Biochem Mol Biol 2000; 125:227-36. [PMID: 10817910 DOI: 10.1016/s0305-0491(99)00173-x] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
A D-galactose binding lectin (SLL-2) was isolated from Sinularia lochmodes, an octocoral, by a combination of affinity chromatography on acid-treated agarose and FPLC on Superdex 200. SLL-2 agglutinated rabbit and horse erythrocytes while SLL-1, a minor component, reacted only with rabbit erythrocytes. SLL-2 is a glycoprotein with a molecular mass of 122 kDa and is composed of eight identical subunits (15 kDa). The sequence of the amino terminal region of SLL-2 did not show any apparent homology to the sequences of other animal and plant lectins. D-Galactose, N-acetyl-D-galactosamine, lactose, and melibiose were moderate inhibitors to the agglutination of rabbit erythrocytes. In contrast, horse erythrocytes were much more susceptible to agglutination by SLL-2, which was inhibited by sugars and glycoproteins such as D-galactose, N-acetyl-D-galactosamine, lactose, melibiose, and porcine stomach mucin. SLL-2 showed considerable tolerance to heating and kept its activity after heating at 80 degrees C for 60 min. In immuno-histochemical studies using an anti-SLL-2 antiserum and protein A gold conjugate, SLL-2 was found to be present in high amounts in the nematocysts. SLL-2 was also detected on the surface of symbiotic dinoflagellate, Symbiodinium sp. cells irrespective whether they were surrounded with or without host cells. These observations suggest the presence of lectin-mediated interaction between symbiotic dinoflagellates and S. lochmodes.
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Affiliation(s)
- M Jimbo
- Department of Marine Biochemistry, Faculty of Fisheries Sciences, Kitasato University, Iwate, Japan
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