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Magarlamov TY, Chernyshev AV. Proboscis sensory cells in Nemertea: comparative morphology and phylogenetic implications. Zool J Linn Soc 2021. [DOI: 10.1093/zoolinnean/zlab106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
Analyses of molecular data have clarified the phylogenetic relations between classes and orders of the phylum Nemertea as a whole, but the ‘deficit’ of morphological synapomorphies characterizing main clades remains problematic. Characters identified with classic histological studies of nemerteans reveal a high level of homoplasy, thus complicating the search for synapomorphies. To identify more potential synapomorphies, sensory cells of the proboscis epithelium of 39 nemertean species were studied with electron and confocal laser-scanning microscopes. Three types of sensory cells were described: monociliated (found in nemerteans from all orders), multiciliated (found only in polystiliferous hoplonemerteans) and nonciliated (found in two species of monostiliferous hoplonemerteans) sensory cells. Monociliated sensory cells of the proboscis have a common structure, differing from monociliated sensory cells of the epidermis and cerebral organ canals. Each monociliated cell consists of a cilium with a bulb-like expanded tip surrounded by a cone-like collar of microvilli, an intra-epithelially located body (perikaryon) and a single basal process (axon). Some features of the monociliated sensory cell structure are thought to provide solid mechanical support. Specific features in the structure of the axial rootlets, cilia, microvillus collars and their microfilaments, considered synapomorphies/autapomorphies, were revealed in the representatives of some nemertean taxa.
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Affiliation(s)
- Timur Yu Magarlamov
- A. V. Zhirmunsky National Scientific Center of Marine Biology, Far Eastern Branch, Russian Academy of Sciences, Vladivostok, Russia
| | - Alexei V Chernyshev
- A. V. Zhirmunsky National Scientific Center of Marine Biology, Far Eastern Branch, Russian Academy of Sciences, Vladivostok, Russia
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Poddubnaya LG, Zhokhov AE, Gibson DI. Ultrastructural features of aporocotylid blood flukes: The tegument and sensory receptors of Sanguinicola inermis Plehn, 1905 from the pike Esox lucius, with a comparative analysis of their traits within the Neodermata. ZOOL ANZ 2020. [DOI: 10.1016/j.jcz.2020.10.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Abstract
SUMMARYAs the most primitive metazoan phylum, the Platyhelminthes occupies a unique position in nervous system evolution. Centrally, their nervous system consists of an archaic brain from which emanate one or more pairs of longitudinal nerve cords connected by commissures; peripherally, a diverse arrangement of nerve plexuses of varying complexity innervate the subsurface epithelial and muscle layers, and in the parasitic taxa they are most prominent in the musculature of the attachment organs and egg-forming apparatus. There is a range of neuronal-cell types, the majority being multi- and bipolar. The flatworm neuron is highly secretory and contains a heterogeneity of vesicular inclusions, dominated by densecored vesicles, whose contents may be released synaptically or by paracrine secretion for presumed delivery to target cells via the extracellular matrix. A wide range of sense organ types is present in flatworms, irrespective of life-styles. The repertoire of neuronal substances identified cytochemically includes all of the major candidate transmitters known in vertebrates. Two groups of native flatworm neuropeptides have been sequenced, neuropeptide F and FMRFamide-related peptides (FaRPs), and immunoreactivities for these have been localised in dense-cored neuronal vesicles in representatives of all major fiatworm groups. There is evidence of co-localisation of peptidergic and cholinergic elements; serotoninergic components generally occupy a separate set of neurons. The actions of neuronal substances in flatworms are largely undetermined, but FaRPs and 5-HT are known to be myoactive in all of the major groups, and there is immuno-cytochemical evidence that they have a role in the mechanism of egg assembly.
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Serotonergic and SCPb-like innervation of the atrial complex in Gyratrix hermaphroditus (Platyhelminthes, Kalyptorhynchia) revealed with CLSM. ZOOMORPHOLOGY 2009. [DOI: 10.1007/s00435-009-0086-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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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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De León RP, Volonterio O. First description of collar receptors in Temnocephalidae (Platyhelminthes). ACTA ZOOL-STOCKHOLM 2003. [DOI: 10.1046/j.1463-6395.2003.00141.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Pfistermüller R, Tyler S. Correlation of fluorescence and electron microscopy of F-actin-containing sensory cells in the epidermis of Convoluta pulchra
(Platyhelminthes: Acoela). ACTA ZOOL-STOCKHOLM 2002. [DOI: 10.1046/j.1463-6395.2002.00095.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Montalvo S, Junoy J, Roldán C, García-Corrales P. Ultrastructural study of sensory cells of the proboscidial glandular epithelium of Riseriellus occultus (Nemertea, Heteronemertea). J Morphol 1996; 229:83-96. [PMID: 29852637 DOI: 10.1002/(sici)1097-4687(199607)229:1<83::aid-jmor5>3.0.co;2-q] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Only one sensory cell type has been observed within the glandular epithelium of the proboscis in the heteronemertine Riseriellus occultus. These bipolar cells are abundant and scattered singly throughout the proboscis length. The apical surface of each dendrite bears a single cilium enclosed by a ring of six to eight prominent microvilli. The cilium has the typical 9×2 + 2 axoneme arrangement and is equipped with a cross-striated vertical rootlet extending from the basal body. No accessory centriole or horizontal rootlet was observed. Large, modified microvilli (stereovilli) surrounding the cilium are joined together by a system of fine filaments derived from the glycocalyx. Each microvillus contains a bundle of actin-like filaments which anchor on the indented inner surface of a dense, apical ring situated beneath the level of the ciliary basal body. The tip of the cilium is expanded and modified to form a bulb-like structure which lies above the level where the surrounding microvilli terminate. In the region where the cilium emerges from the microvillar cone, the membrane of the microvillar apices makes contact with a corresponding portion of the ciliary membrane. At this level microvilli and cilium are apparently firmly linked by junctional systems resembling adherens junctions. The results suggest that these sensory cells may be mechanoreceptors. © 1996 Wiley-Liss, Inc.
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Affiliation(s)
- Sagrario Montalvo
- Department of Animal Biology, University of Alcalá de Henares, E-28871, Alcalá de Henares, Madrid, Spain
| | - Juan Junoy
- Department of Animal Biology, University of Alcalá de Henares, E-28871, Alcalá de Henares, Madrid, Spain
| | - Carmen Roldán
- Department of Animal Biology I, Faculty of Biology, University Complutense, E-28040, Madrid, Spain
| | - Pedro García-Corrales
- Department of Animal Biology, University of Alcalá de Henares, E-28871, Alcalá de Henares, Madrid, Spain
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Abstract
The flatworms occupy a position at the base of the metazoan phylogenetic tree; they have a bilateral symmetric nervous system and an archaic brain. The following aspects, brought into focus by the use of new methods, will be dealt with in the present paper. 1. The high degree of diversity on all levels of the flatworm nervous system (NS). 2. The concept of main nerve cords is defined and the use of this concept in avoiding confusions in the terminology of nerve cords is stressed. 3. The archaic nature of the stomatogastric NS is reviewed. 4. The new data about neuronal celltypes implying advanced features at this low phylogenetic level. 5. The ultrastructural studies of neuronal cells indicating (A) that a common secretory cell type containing dense-core vesicles is archaic and a likely progenitor cell type for conventional neurons of advanced flatworms and (B) that an independent evolution of synaptic structures and glial cells has occurred inside the flatworm taxon. 6. The multitude of neuroactive substances demonstrated by light microscopic histofluorescence, immunocytochemistry, liquid chromatography, and HPLC. The cholinergic, aminergic, and peptidergic substances often occur in different neuronal compartments.
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Affiliation(s)
- M Reuter
- Department of Biology, Abo Akademi University, Finland
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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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Pedersen KJ. Invited Review: Structure and Composition of Basement Membranes and Other Basal Matrix Systems in Selected Invertebrates. ACTA ZOOL-STOCKHOLM 1991. [DOI: 10.1111/j.1463-6395.1991.tb01196.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Vocht A. The Ultrastructure of the Proboscis inPsammorhynchus tubulipenisKarling, 1964 andCytocystis clitellatusKarling, 1953 (Platyhelminthes, Rhabdocoela). ACTA ZOOL-STOCKHOLM 1990. [DOI: 10.1111/j.1463-6395.1990.tb01076.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Rohde K. At least eight types of sense receptors in an endoparasitic flatworm: a counter-trend to sacculinization. THE SCIENCE OF NATURE - NATURWISSENSCHAFTEN 1989; 76:383-5. [PMID: 2779668 DOI: 10.1007/bf00366214] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- K Rohde
- Department of Zoology, University of New England, Armidale, N.S.W., Australia
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De Vocht AJP. Ultrastructure of the proboscis in Cystiplanidae, (Plathelminthes, Kalyptorhynchia). ZOOMORPHOLOGY 1989. [DOI: 10.1007/bf00312178] [Citation(s) in RCA: 8] [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, Lehtonen M, Wikgren M. Immunocytochemical Evidence of Neuroactive Substances in Flatworms of Different Taxa-a Comparison. ACTA ZOOL-STOCKHOLM 1988. [DOI: 10.1111/j.1463-6395.1988.tb00898.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Types of sensory cells in Notocotylus attenuates (Rud., 1809) rediae (Digenea, Notocotylidae). Parasitol Res 1988. [DOI: 10.1007/bf00539572] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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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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Br�ggemann J. Ultrastruktur und Bildungsweise penialer Hartstrukturen bei freilebenden Plathelminthen. ZOOMORPHOLOGY 1985. [DOI: 10.1007/bf00312155] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.8] [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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Rohde K, Garlick PR. Two ciliate sense receptors in the larva of Austramphilina elongata Johnston, 1931 (Amphilinidea). ZOOMORPHOLOGY 1985. [DOI: 10.1007/bf00312070] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Epidermale Collar-Receptoren der Nematoplanidae und Polystyliphoridae (Plathelminthes, Unguiphora). ZOOMORPHOLOGY 1984. [DOI: 10.1007/bf00312035] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Pedersen KJ. Fine Structural Observations on the TurbellariansStenostomumsp. andMicrostomum linearewith Special Reference to the Extracellular Matrix and Connective Tissue Systems. ACTA ZOOL-STOCKHOLM 1983. [DOI: 10.1111/j.1463-6395.1983.tb00799.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Reuter M, Lindroos P. The Ultrastructure of the Nervous System ofGyratrix hermaphroditus(Turbellaria, Rhabdocoela). ACTA ZOOL-STOCKHOLM 1979. [DOI: 10.1111/j.1463-6395.1979.tb00608.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Ehlers U, Ehlers B. Monociliary receptors in interstitial Proseriata and Neorhabdocoela (Turbellaria Neoophora). ACTA ACUST UNITED AC 1977. [DOI: 10.1007/bf00993666] [Citation(s) in RCA: 43] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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