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de Miguel Bonet MDM, Hartenstein V. Ultrastructural analysis and 3D reconstruction of the frontal sensory-glandular complex and its neural projections in the platyhelminth Macrostomum lignano. Cell Tissue Res 2024:10.1007/s00441-024-03901-x. [PMID: 38898317 DOI: 10.1007/s00441-024-03901-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2024] [Accepted: 06/04/2024] [Indexed: 06/21/2024]
Abstract
The marine microturbellarian Macrostomum lignano (Platyhelminthes, Rhabditophora) is an emerging laboratory model used by a growing community of researchers because it is easy to cultivate, has a fully sequenced genome, and offers multiple molecular tools for its study. M. lignano has a compartmentalized brain that receives sensory information from receptors integrated in the epidermis. Receptors of the head, as well as accompanying glands and specialized epidermal cells, form a compound sensory structure called the frontal glandular complex. In this study, we used semi-serial transmission electron microscopy (TEM) to document the types, ultrastructure, and three-dimensional architecture of the cells of the frontal glandular complex. We distinguish a ventral compartment formed by clusters of type 1 (multiciliated) sensory receptors from a central domain where type 2 (collar) sensory receptors predominate. Six different types of glands (rhammite glands, mucoid glands, glands with aster-like and perimaculate granula, vacuolated glands, and buckle glands) are closely associated with type 1 sensory receptors. Endings of a seventh type of gland (rhabdite gland) define a dorsal domain of the frontal glandular complex. A pair of ciliary photoreceptors is closely associated with the base of the frontal glandular complex. Bundles of dendrites, connecting the receptor endings with their cell bodies which are located in the brain, form the (frontal) peripheral nerves. Nerve fibers show a varicose structure, with thick segments alternating with thin segments, and are devoid of a glial layer. This distinguishes platyhelminths from larger and/or more complex invertebrates whose nerves are embedded in prominent glial sheaths.
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Affiliation(s)
- Maria Del Mar de Miguel Bonet
- Department of Molecular, Cell and Developmental Biology, University of California Los Angeles (UCLA), Los Angeles, CA, USA
- Department of Biomedicine and Biotechnology, University of Alcalá (UAH), Madrid, Spain
- BioWorld Science, Clarivate Analytics, Barcelona, Spain
| | - Volker Hartenstein
- Department of Molecular, Cell and Developmental Biology, University of California Los Angeles (UCLA), Los Angeles, CA, USA.
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Poddubnaya LG, Warren MB, Bullard SA. FOREGUT ULTRASTRUCTURE OF ADULT SANGUINICOLA VOLGENSIS (RAŠÍN, 1929) MCINTOSH, 1934 (DIGENEA: APOROCOTYLIDAE). J Parasitol 2023; 109:27-34. [PMID: 36826441 DOI: 10.1645/22-79] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023] Open
Abstract
Herein, we use scanning and transmission electron microscopy to describe the foregut (mouth, pharyngeal canal, and associated epithelia and musculature) of an adult freshwater fish blood fluke, Sanguinicola volgensis (Rašín, 1929) McIntosh, 1934, infecting the blood of sabre, Pelecus cultratus Linnaeus, 1758 (Cypriniformes: Leuciscidae) from the Volga River, Russia. Our results indicate that S. volgensis has a pharynx and lacks an oral sucker and that its pharyngeal canal acts as a peristaltic pump that sucks blood into the esophagus, whereupon digestion commences with granules secreted from the esophageal epithelium. We saw no evidence of longitudinal muscle fibers beneath the pharyngeal canal epithelium, pharyngeal glands, or pharyngeal epithelial cells or muscle cells within the pharyngeal muscular complex; collectively indicating the presence of a pharynx rather than an oral sucker. The specialized epithelial lining associated with the mouth and pharyngeal canal evidently is unique among neodermatans; it is smooth, ∼40 nm thick anteriorly, and thickens (∼250-700 nm) posteriorly as the mouth cavity transitions into the pharyngeal canal. The pharyngeal canal epithelium has lumps of dense material resembling those of the basal lamina and fibrous coat of the tegument. The actin-like material within the pharyngeal cavity epithelium could provide structural support to the pharynx.
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Affiliation(s)
- Larisa G Poddubnaya
- Papanin Institute for Biology of Inland Waters, Russian Academy of Sciences, Borok, Yaroslavl Province 152742, Russia
| | - Micah B Warren
- Aquatic Parasitology Laboratory and Southeastern Cooperative Fish Parasite and Disease Laboratory, Auburn University, 559 Devall Drive, Auburn, Alabama, 36832
| | - Stephen A Bullard
- Aquatic Parasitology Laboratory and Southeastern Cooperative Fish Parasite and Disease Laboratory, Auburn University, 559 Devall Drive, Auburn, Alabama, 36832.,Department of Zoology, School for Environmental Sciences and Development, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa
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Fegley SR, Smith JPS, Johnson D, Schirmer A, Jones-Boggs J, Edmonds A, Bursey J. Nourished, Exposed Beaches Exhibit Altered Sediment Structure and Meiofaunal Communities. DIVERSITY-BASEL 2020; 12. [PMID: 34168518 PMCID: PMC8221582 DOI: 10.3390/d12060245] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
To retain recreational uses and shoreline protection, a large proportion of ocean beaches have been, and continue to be, nourished. Adding sand from subtidal and terrestrial sources to nourish beaches rarely re-creates the original sediment structure of the beach. Numerous studies have demonstrated that meiofaunal communities are altered by changes in sediment composition in low-energy substrates, therefore, we have explored whether beach nourishment has affected exposed, ocean beach meiofaunal communities. Since the early 2000s, we have conducted a series of sampling and experimental studies on meiofauna and sediments on nourished beaches in coastal North Carolina USA that had been sampled previously in the early 1970s, prior to any beach nourishment. Most of our studies consider meiofauna at the level of major taxa only. However, a few studies examine free-living flatworm (turbellarian) species in detail because of the existence of historical studies examining this group. Comparison of contemporary results to historical data and of heavily nourished versus lightly nourished beaches reveals extensive changes to beach sediment structure and meiofaunal community composition, indicating that the beaches are a more heterogeneous habitat than in the past. The effects of these substantial physical and biological changes to the production of beach ecosystem services are unlikely to be inconsequential.
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Affiliation(s)
- Stephen R. Fegley
- Institute of Marine Sciences, University of North Carolina at Chapel Hill, Morehead City, NC 28557, USA
| | - Julian P. S. Smith
- Department of Biology, Winthrop University, Rock Hill, SC 29733, USA
- Correspondence:
| | - Douglas Johnson
- Department of Biology, Winthrop University, Rock Hill, SC 29733, USA
| | - Amelia Schirmer
- Institute of Marine Sciences, University of North Carolina at Chapel Hill, Morehead City, NC 28557, USA
| | | | - Austin Edmonds
- Department of Biology, Barton College, Wilson, NC 27893, USA
| | - Joseph Bursey
- Department of Biology, Winthrop University, Rock Hill, SC 29733, USA
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Phagocytosis in cellular defense and nutrition: a food-centered approach to the evolution of macrophages. Cell Tissue Res 2019; 377:527-547. [PMID: 31485720 DOI: 10.1007/s00441-019-03096-6] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 08/13/2019] [Indexed: 12/13/2022]
Abstract
The uptake of macromolecules and larger energy-rich particles into the cell is known as phagocytosis. Phagocytosed material is enzymatically degraded in membrane-bound vesicles of the endosome/lysosome system (intracellular digestion). Whereas most, if not all, cells of the animal body are equipped with the molecular apparatus for phagocytosis and intracellular digestion, a few cell types are specialized for a highly efficient mode of phagocytosis. These are the ("professional") macrophages, motile cells that seek out and eliminate pathogenic invaders or damaged cells. Macrophages form the backbone of the innate immune system. Developmentally, they derive from specialized compartments within the embryonic mesoderm and early vasculature as part of the process of hematopoiesis. Intensive research has revealed in detail molecular and cellular mechanisms of phagocytosis and intracellular digestion in macrophages. In contrast, little is known about a second type of cell that is "professionally" involved in phagocytosis, namely the "enteric phagocyte." Next to secretory (zymogenic) cells, enteric phagocytes form one of the two major cell types of the intestine of most invertebrate animals. Unlike vertebrates, these invertebrates only partially digest food material in the intestinal lumen. The resulting food particles are absorbed by phagocytosis or pinocytosis and digested intracellularly. In this review, we provide a brief overview of the enteric phagocytes described electron microscopically for diverse invertebrate clades, to then to compare these cells with the "canonical" phagocyte ultrastructure established for macrophages. In addition, we will review observations and speculations associated with the hypothesis that macrophages are evolutionarily derived from enteric phagocytes. This idea was already proposed in the late nineteenth century by Elias Metschnikoff who pioneered the research of phagocytosis for both macrophages and enteric phagocytes. We presume that modern approaches to better understand phagocytosis will be helped by considering the deep evolutionary relationship between the two cell types.
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Fromm B, Tosar JP, Aguilera F, Friedländer MR, Bachmann L, Hejnol A. Evolutionary Implications of the microRNA- and piRNA Complement of Lepidodermella squamata (Gastrotricha). Noncoding RNA 2019; 5:E19. [PMID: 30813358 PMCID: PMC6468455 DOI: 10.3390/ncrna5010019] [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: 12/21/2018] [Revised: 02/15/2019] [Accepted: 02/19/2019] [Indexed: 02/06/2023] Open
Abstract
Gastrotrichs-'hairy bellies'-are microscopic free-living animals inhabiting marine and freshwater habitats. Based on morphological and early molecular analyses, gastrotrichs were placed close to nematodes, but recent phylogenomic analyses have suggested their close relationship to flatworms (Platyhelminthes) within Spiralia. Small non-coding RNA data on e.g., microRNAs (miRNAs) and PIWI-interacting RNAs (piRNA) may help to resolve this long-standing question. MiRNAs are short post-transcriptional gene regulators that together with piRNAs play key roles in development. In a 'multi-omics' approach we here used small-RNA sequencing, available transcriptome and genomic data to unravel the miRNA- and piRNA complements along with the RNAi (RNA interference) protein machinery of Lepidodermella squamata (Gastrotricha, Chaetonotida). We identified 52 miRNA genes representing 35 highly conserved miRNA families specific to Eumetazoa, Bilateria, Protostomia, and Spiralia, respectively, with overall high similarities to platyhelminth miRNA complements. In addition, we found four large piRNA clusters that also resemble flatworm piRNAs but not those earlier described for nematodes. Congruently, transcriptomic annotation revealed that the Lepidodermella protein machinery is highly similar to flatworms, too. Taken together, miRNA, piRNA, and protein data support a close relationship of gastrotrichs and flatworms.
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Affiliation(s)
- Bastian Fromm
- Science for Life Laboratory, Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, S-10691 Stockholm, Sweden.
| | - Juan Pablo Tosar
- Functional Genomics Unit, Institut Pasteur de Montevideo, Montevideo 11400, Uruguay.
- Nuclear Research Center, Faculty of Science, Universidad de la República, Montevideo 11400, Uruguay.
| | - Felipe Aguilera
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Casilla 160_C, Concepción 3349001, Chile.
- Sars International Centre for Marine Molecular Biology, University of Bergen, 5006 Bergen, Norway.
| | - Marc R Friedländer
- Science for Life Laboratory, Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, S-10691 Stockholm, Sweden.
| | - Lutz Bachmann
- Research group Frontiers in Evolutionary Zoology, Natural History Museum, University of Oslo, 0318 Oslo, Norway.
| | - Andreas Hejnol
- Sars International Centre for Marine Molecular Biology, University of Bergen, 5006 Bergen, Norway.
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Adami ML, Brusa F, Ronderos JR, Damborenea C. Muscular pattern in three species ofMacrostomum(platyhelminthes, macrostomorpha). J Morphol 2016; 278:264-282. [DOI: 10.1002/jmor.20633] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 08/19/2016] [Accepted: 11/01/2016] [Indexed: 11/05/2022]
Affiliation(s)
- Mariana L. Adami
- División Zoología Invertebrados; Museo de La Plata (FCNyM-UNLP); CONICET. Paseo del Bosque s/n La Plata 1900 Argentina
- Cátedra de Histología y Embriología Animal (FCNyM-UNLP); Calle 64 N°3 La Plata 1900 Argentina
| | - Francisco Brusa
- División Zoología Invertebrados; Museo de La Plata (FCNyM-UNLP); CONICET. Paseo del Bosque s/n La Plata 1900 Argentina
| | - Jorge R. Ronderos
- Cátedra de Histología y Embriología Animal (FCNyM-UNLP); Calle 64 N°3 La Plata 1900 Argentina
| | - Cristina Damborenea
- División Zoología Invertebrados; Museo de La Plata (FCNyM-UNLP); CONICET. Paseo del Bosque s/n La Plata 1900 Argentina
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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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Struck TH, Wey-Fabrizius AR, Golombek A, Hering L, Weigert A, Bleidorn C, Klebow S, Iakovenko N, Hausdorf B, Petersen M, Kück P, Herlyn H, Hankeln T. Platyzoan paraphyly based on phylogenomic data supports a noncoelomate ancestry of spiralia. Mol Biol Evol 2014; 31:1833-49. [PMID: 24748651 DOI: 10.1093/molbev/msu143] [Citation(s) in RCA: 112] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Based on molecular data three major clades have been recognized within Bilateria: Deuterostomia, Ecdysozoa, and Spiralia. Within Spiralia, small-sized and simply organized animals such as flatworms, gastrotrichs, and gnathostomulids have recently been grouped together as Platyzoa. However, the representation of putative platyzoans was low in the respective molecular phylogenetic studies, in terms of both, taxon number and sequence data. Furthermore, increased substitution rates in platyzoan taxa raised the possibility that monophyletic Platyzoa represents an artifact due to long-branch attraction. In order to overcome such problems, we employed a phylogenomic approach, thereby substantially increasing 1) the number of sampled species within Platyzoa and 2) species-specific sequence coverage in data sets of up to 82,162 amino acid positions. Using established and new measures (long-branch score), we disentangled phylogenetic signal from misleading effects such as long-branch attraction. In doing so, our phylogenomic analyses did not recover a monophyletic origin of platyzoan taxa that, instead, appeared paraphyletic with respect to the other spiralians. Platyhelminthes and Gastrotricha formed a monophylum, which we name Rouphozoa. To the exclusion of Gnathifera, Rouphozoa and all other spiralians represent a monophyletic group, which we name Platytrochozoa. Platyzoan paraphyly suggests that the last common ancestor of Spiralia was a simple-bodied organism lacking coelomic cavities, segmentation, and complex brain structures, and that more complex animals such as annelids evolved from such a simply organized ancestor. This conclusion contradicts alternative evolutionary scenarios proposing an annelid-like ancestor of Bilateria and Spiralia and several independent events of secondary reduction.
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Affiliation(s)
- Torsten H Struck
- Zoological Research Museum Alexander Koenig, Bonn, GermanyUniversity of Osnabrück, FB05 Biology/Chemistry, AG Zoology, Osnabrück, Germany
| | - Alexandra R Wey-Fabrizius
- Institute of Molecular Genetics, Biosafety Research and Consulting, Johannes Gutenberg University, Mainz, Germany
| | - Anja Golombek
- Zoological Research Museum Alexander Koenig, Bonn, Germany
| | - Lars Hering
- Animal Evolution and Development, Institute of Biology II, University of Leipzig, Leipzig, Germany
| | - Anne Weigert
- Molecular Evolution and Systematics of Animals, Institute of Biology, University of Leipzig, Leipzig, Germany
| | - Christoph Bleidorn
- Molecular Evolution and Systematics of Animals, Institute of Biology, University of Leipzig, Leipzig, Germany
| | - Sabrina Klebow
- Institute of Molecular Genetics, Biosafety Research and Consulting, Johannes Gutenberg University, Mainz, Germany
| | - Nataliia Iakovenko
- Department of Biology and Ecology, Ostravian University in Ostrava, Ostrava, Czech RepublicDepartment of Invertebrate Fauna and Systematics, Schmalhausen Institute of Zoology NAS of Ukraine, Kyiv, Ukraine
| | | | - Malte Petersen
- Zoological Research Museum Alexander Koenig, Bonn, Germany
| | - Patrick Kück
- Zoological Research Museum Alexander Koenig, Bonn, Germany
| | - Holger Herlyn
- Institute of Anthropology, Johannes Gutenberg University, Mainz, Germany
| | - Thomas Hankeln
- Institute of Molecular Genetics, Biosafety Research and Consulting, Johannes Gutenberg University, Mainz, Germany
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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: 36] [Impact Index Per Article: 3.0] [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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Moreno E, Permanyer J, Martinez P. The origin of patterning systems in bilateria-insights from the Hox and ParaHox genes in Acoelomorpha. GENOMICS PROTEOMICS & BIOINFORMATICS 2012; 9:65-76. [PMID: 21802044 PMCID: PMC5054442 DOI: 10.1016/s1672-0229(11)60010-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Accepted: 02/24/2011] [Indexed: 01/22/2023]
Abstract
Hox and ParaHox genes constitute two families of developmental regulators that pattern the Anterior–Posterior body axis in all bilaterians. The members of these two groups of genes are usually arranged in genomic clusters and work in a coordinated fashion, both in space and in time. While the mechanistic aspects of their action are relatively well known, it is still unclear how these systems evolved. For instance, we still need a proper model of how the Hox and ParaHox clusters were assembled over time. This problem is due to the shortage of information on gene complements for many taxa (mainly basal metazoans) and the lack of a consensus phylogenetic model of animal relationships to which we can relate our new findings. Recently, several studies have shown that the Acoelomorpha most probably represent the first offshoot of the Bilateria. This finding has prompted us, and others, to study the Hox and ParaHox complements in these animals, as well as their activity during development. In this review, we analyze how the current knowledge of Hox and ParaHox genes in the Acoelomorpha is shaping our view of bilaterian evolution.
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Todt C. Structure and evolution of the pharynx simplex in acoel flatworms (Acoela). J Morphol 2009; 270:271-90. [PMID: 18942704 DOI: 10.1002/jmor.10682] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The homology of pharynges within the mostly pharynx-less Acoela has been a matter of discussion for decades and even the basic question of whether a pharynx is a primitive trait within the Acoela and homologous to the pharynx of platyhelminth turbellarians is open. By using fluorescence staining of musculature, as well as conventional histological techniques and transmission electron microscopy, the present study sets focus on the mouth and pharynx (where present) of seven species of Acoela within Paratomellidae, Solenofilomorphidae, Hofsteniidae, Proporidae, and Convolutidae, as well as one species of Nemertodermatida and Catenulida, respectively. It is shown that among the investigated families of acoels there is a great variability in muscle systems associated with the mouth and pharynx and that pharynx histology and ultrastructural characters are widely diverse. There are no close similarities between the acoel pharynges and the catenulid pharynx but there is a general resemblance of the musculature associated with the mouth in the representatives of Paratomellidae and Nemertodermatida. On the basis of the profound differences in pharynx morphology, three major conclusions are drawn: 1) the pharynges as present in Recent acoels are not homologous to the pharynx simplex characteristic for Catenulida and Macrostomida within the Platyhelminthes; 2) the different muscular pharynx types of acoels are not homologous between higher taxa and thus a single acoel-type pharynx simplex cannot be defined; 3) the presence of a muscular pharynx most likely does not represent the ancestral state.
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Affiliation(s)
- Christiane Todt
- Department of Biology, University of Bergen, 5020 Bergen, Norway.
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12
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Todt C, Tyler S. Ciliary receptors associated with the mouth and pharynx of Acoela (Acoelomorpha): a comparative ultrastructural study. ACTA ZOOL-STOCKHOLM 2006. [DOI: 10.1111/j.1463-6395.2007.00246.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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13
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Morris J, Ladurner P, Rieger R, Pfister D, Del Mar De Miguel-Bonet M, Jacobs D, Hartenstein V. The Macrostomum lignano EST database as a molecular resource for studying platyhelminth development and phylogeny. Dev Genes Evol 2006; 216:695-707. [PMID: 17021863 DOI: 10.1007/s00427-006-0098-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2006] [Accepted: 06/20/2006] [Indexed: 12/31/2022]
Abstract
We report the development of an Expressed Sequence Tag (EST) resource for the flatworm Macrostomum lignano. This taxon is of interest due to its basal placement within the flatworms. As such, it provides a useful comparative model for understanding the development of neural and sensory organization. It was anticipated on the basis of previous studies [e.g., Sánchez-Alvarado et al., Development, 129:5659-5665, (2002)] that a wide range of developmental markers would be expressed in later-stage macrostomids, and this proved to be the case, permitting recovery of a range of gene sequences important in development. To this end, an adult Macrostomum cDNA library was generated and 7,680 Macrostomum ESTs were sequenced from the 5' end. In addition, 1,536 of these aforementioned sequences were sequenced from the 3' end. Of the roughly 5,416 non-redundant sequences identified, 68% are similar to previously reported genes of known function. In addition, nearly 100 specific clones were obtained with potential neural and sensory function. From these data, an annotated searchable database of the Macrostomum EST collection has been made available on the web. A major objective was to obtain genes that would allow reconstruction of embryogenesis, and in particular neurogenesis, in a basal platyhelminth. The sequences recovered will serve as probes with which the origin and morphogenesis of lineages and tissues can be followed. To this end, we demonstrate a protocol for combined immunohistochemistry and in situ hybridization labeling in juvenile Macrostomum, employing homologs of lin11/lim1 and six3/optix. Expression of these genes is shown in the context of the neuropile/muscle system.
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Affiliation(s)
- Joshua Morris
- Department of Molecular, Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA 90095, USA
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Todt C, Tyler S. Morphology and ultrastructure of the pharynx in Solenofilomorphidae (Acoela). J Morphol 2006; 267:776-92. [PMID: 16555253 DOI: 10.1002/jmor.10440] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The homology of pharynges within the mostly pharynx-less Acoela has been a matter of discussion for decades. Here, we analyze the pharynges of three members of the Solenofilomorphidae, Myopea sp. and two species of the genus Solenofilomorpha, by means of light and transmission electron microscopy. Special focus is placed on the ultrastructure of the pharyngeal musculature, epidermis surrounding the mouth, pharyngeal epithelium, and junction with the digestive parenchyma. The main goal of this study was to evaluate the usefulness of certain characters for broader comparisons within the Acoela. Among the three species, characters relating to position of the mouth, presence and elaboration of sphincter muscles, presence of pharyngeal glands, and ultrastructure of epitheliosomes proved to be variously species- and genus-specific. The arrangement of pharyngeal muscles and their connection with body wall musculature, ultrastructure of receptor cells, and morphology of a nonciliated glandular region in the posterior pharynx, in contrast, appear to be characteristic of the family Solenofilomorphidae and thus of predominant interest for comparisons with other acoel families.
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Affiliation(s)
- Christiane Todt
- Department of Biological Sciences, University of Maine, Orono, Maine 04469, USA.
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15
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Ladurner P, Scharer L, Salvenmoser W, Rieger RM. A new model organism among the lower Bilateria and the use of digital microscopy in taxonomy of meiobenthic Platyhelminthes: Macrostomum lignano, n. sp. (Rhabditophora, Macrostomorpha). J ZOOL SYST EVOL RES 2005. [DOI: 10.1111/j.1439-0469.2005.00299.x] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Hooge MD, Tyler S. New tools for resolving phylogenies: a systematic revision of the Convolutidae (Acoelomorpha, Acoela). J ZOOL SYST EVOL RES 2005. [DOI: 10.1111/j.1439-0469.2005.00301.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Tyler S, Hooge M. Comparative morphology of the body wall in flatworms (Platyhelminthes). CAN J ZOOL 2004. [DOI: 10.1139/z03-222] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The soft-bodied nature of the platyhelminths is due largely to the structure of the body wall and its lack of sclerotic elements such as cuticle. Free-living members, i.e., most turbellarians, show considerable variety, but the basic form of the body wall comprises a simple ciliated epithelium overlying a network of muscles. We illustrate this body wall structure in a representative typhloplanoid rhabditophoran and discuss variations in representatives of the Acoela, Catenulida, and other free-living rhabditophorans. The major parasitic groups of platyhelminths, the rhabditophoran Neodermata, follow a developmental pattern that replaces a similar ciliated epidermis in a larval stage with a specialized epidermis called a neodermis, which is assumed to be key to their success as parasites. This neodermis consists of a syncytium that covers the body in a continuous sheet connected to perikarya that lie below the body wall musculature. The neodermis can be seen as a special adaptation of a developmental mechanism common to all platyhelminths, in which epidermal growth and renewal are accomplished by replacement cells originating beneath the body wall. The cell type responsible for all cell renewal, including body wall renewal, in platyhelminths is the neoblast, and its presence may be the one autapomorphic character that unites all taxonomic groups of platyhelminths.
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Hooge MD. Evolution of body-wall musculature in the Platyhelminthes (Acoelomorpha, Catenulida, Rhabditophora). J Morphol 2001; 249:171-94. [PMID: 11517463 DOI: 10.1002/jmor.1048] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
In an effort to understand the phylogeny of the Platyhelminthes, the patterns of body-wall musculature of flatworms were studied using fluorescence microscopy and Alexa-488-labeled phalloidin. Species of the Catenulida have a simple orthogonal gridwork of longitudinal and circular muscles. Members of the Rhabditophora have the same gridwork of musculature, but also have diagonal muscles over their entire body. Although a few species of Acoelomorpha possessed a simple orthogonal grid of musculature, most species typically have distinctly different patterns of dorsal and ventral body-wall musculature that include sets of longitudinal, circular, U-shaped, and several kinds of diagonal muscles. Several distinct patterns of musculature were identified, including 8 patterns in 11 families of acoels. These patterns have proven to be useful in clarifying the phylogeny of the Acoelomorpha, particularly with regard to the higher acoels. Patterns of musculature as well as other morphological characters are used here for revisions of acoel systematics, including the return of Eumecynostomum sanguineum (Mecynostomidae) to the genus Aphanostoma (Convolutidae), the revision of the family Childiidae, and the formation of a new family, Actinoposthiidae.
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Affiliation(s)
- M D Hooge
- Department of Biological Sciences, University of Maine, Orono, Maine 04469-5751, USA.
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Abstract
In an effort to understand how the feeding motions of Urastoma cyprinae are generated, the arrangement of its musculature was studied using fluorescence microscopy of phalloidin-linked fluorescent stains and conventional light histology and transmission electron microscopy. BODIPY 558/568 phalloidin and Alexa 488 phalloidin resolved a meshwork of ribbon-shaped body-wall muscles as well as inner-body musculature associated with the pharynx and male copulatory organ. The general pattern of body-wall muscles in U. cyprinae is similar to that of other rhabdocoel turbellarians in consisting only of circular, longitudinal, and diagonal fibers; the arrangement of these muscles readily correlates with the bending motions the animal undergoes as it feeds at the surface of gills in bivalves it parasitizes. The orogenital atrium of U. cyprinae lies at the posterior apex of the body, opening at a terminal pore. As evidenced by the arrangement of its epithelium and musculature, it appears to be an invagination of the body wall and comes closest of any such duct studied in turbellarians to satisfying the hypothetical model of a "pseudopharynx," ostensibly adapted as an organ for swallowing and so supplementing the ingestive role of the animal's true pharynx.
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Affiliation(s)
- M D Hooge
- Department of Biological Sciences, University of Maine, Orono, Maine, USA.
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Joffe BI, Solovei IV, Watson NA, Cannon LRG. Structure and evolution of the pharynx in the Temnocephalida (Platyhelminthes). CAN J ZOOL 1997. [DOI: 10.1139/z97-028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The structure of the pharynx was studied in the genera Didymorchis, Diceratocephala, Temnocephala, and Craspedella, using light microscopy, silver nitrate staining, and transmission electron microscopy. Based on these data, evolution of this organ within the Temnocephalida is analysed. In addition to the specific pattern of muscle fibres in the walls of the pharynx known from earlier studies, three other features characteristic of the pharynges of temnocephalids were found: (1) multisyncytial organization of the pharyngeal epithelium, (2) the presence of type 1 sensory receptors, and (3) muscle fibres incorporated into the epithelium of the pharynx. Features deduced to be characteristic of the pharynx in primitive temnocephalids are (i) the presence of three types of sensory receptors with specific morphologies and locations in the pharynx, (ii) the presence of a bundle of muscle fibres that traverses the epithelium surrounding the anterior margin of the pharynx, (iii) characteristic lamellation of the epithelium of the pharynx proper, and (iv) a narrow syncytium nesting the openings of the pharyngeal glands and forming deep invaginations into which the gland ducts open. The most prominent tendencies in the evolution of the pharynx are reinforcement of the pharyngeal musculature (related to the mode of feeding) and reduction in the number of syncytia.
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Antoniazzi MM, Silveira M. Studies onStenostomum grandeChild, 1902 (Platyhelminthes, Catenulida): fine structure of the digestive tract and the endocytotic activity of the gastrodermis. ACTA ZOOL-STOCKHOLM 1996. [DOI: 10.1111/j.1463-6395.1996.tb01250.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Phalloidin-rhodamine preparations of Macrostomum hystricinum marinum (Plathelminthes): morphology and postembryonic development of the musculature. ZOOMORPHOLOGY 1994. [DOI: 10.1007/bf00403261] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Antoniazzi MM, Silveira M. Pharyngeal and Gastrodermal Ultrastructure ofProrhynchus stagnalisSchultze, 1851 (Turbellaria, Lecithoepitheliata). ACTA ZOOL-STOCKHOLM 1992. [DOI: 10.1111/j.1463-6395.1992.tb01090.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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WATSON NIKKIA, ROHDE KLAUS. Ultrastructure of the pharynx of Prorhynchus (Platyhelminthes, Lecithoepitheliata). ZOOL SCR 1992. [DOI: 10.1111/j.1463-6409.1992.tb00334.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Reuter M, Palmberg I. An Ultrastructural and Immunocytochemical Study of Gastrodermal Cell Types inMicrostomum lineare(Turbellaria, Macrostomida). ACTA ZOOL-STOCKHOLM 1987. [DOI: 10.1111/j.1463-6395.1987.tb00886.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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KLAUSER MARIANNED, TYLER SETH. Frontal glands and frontal sensory structures in the Macrostomida (Turbellaria). ZOOL SCR 1987. [DOI: 10.1111/j.1463-6409.1987.tb00057.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Doe DA. Ultrastructure of the copulatory organ of Haplopharynx quadristimulus and its phylogenetic significance (Plathelminthes, Haplopharyngida). ZOOMORPHOLOGY 1986. [DOI: 10.1007/bf00312205] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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SMITH JULIANPS, TYLER SETH. Fine-Structure and Evolutionary Implications of the Frontal Organ in Turbellaria Acoela. 1 Diopisthoporus gymnopharyngeus sp.n. ZOOL SCR 1985. [DOI: 10.1111/j.1463-6409.1985.tb00180.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Turbeville JM, Ruppert EE. Epidermal muscles and peristaltic burrowing in Carinoma tremaphoros (Nemertini): Correlates of effective burrowing without segmentation. ZOOMORPHOLOGY 1983. [DOI: 10.1007/bf00312241] [Citation(s) in RCA: 37] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Curtis SK, Cowden RR, Moore JD, Robertson JL. Histochemical and ultrastructural features of the epidermis of the land planarianBipalium adventitium. J Morphol 1983; 175:171-194. [DOI: 10.1002/jmor.1051750206] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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