Organization of the central nervous system and innervation of cephalic sensory structures in the water bear Echiniscus testudo (Tardigrada: Heterotardigrada) revisited
Abstract The tardigrade brain has been the topic of several neuroanatomical studies, as it is key to understanding the evolution of the central nervous systems in Panarthropoda (Tardigrada + Onychophora + Arthropoda). The gross morphology of the brain seems to be well conserved across tardigrades de...
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crwiley:10.1002/jmor.21386 2024-06-02T08:16:04+00:00 Organization of the central nervous system and innervation of cephalic sensory structures in the water bear Echiniscus testudo (Tardigrada: Heterotardigrada) revisited Gross, Vladimir Epple, Lisa Mayer, Georg 2021 http://dx.doi.org/10.1002/jmor.21386 https://onlinelibrary.wiley.com/doi/pdf/10.1002/jmor.21386 https://onlinelibrary.wiley.com/doi/full-xml/10.1002/jmor.21386 en eng Wiley http://creativecommons.org/licenses/by/4.0/ Journal of Morphology volume 282, issue 9, page 1298-1312 ISSN 0362-2525 1097-4687 journal-article 2021 crwiley https://doi.org/10.1002/jmor.21386 2024-05-03T11:55:14Z Abstract The tardigrade brain has been the topic of several neuroanatomical studies, as it is key to understanding the evolution of the central nervous systems in Panarthropoda (Tardigrada + Onychophora + Arthropoda). The gross morphology of the brain seems to be well conserved across tardigrades despite often disparate morphologies of their heads and cephalic sensory structures. As such, the general shape of the brain and its major connections to the rest of the central nervous system have been mapped out already by early tardigradologists. Despite subsequent investigations primarily based on transmission electron microscopy or immunohistochemistry, characterization of the different regions of the tardigrade brain has progressed relatively slowly and open questions remain. In an attempt to improve our understanding of different brain regions, we reinvestigated the central nervous system of the heterotardigrade Echiniscus testudo using anti‐synapsin and anti‐acetylated α‐tubulin immunohistochemistry in order to visualize the number and position of tracts, commissures, and neuropils. Our data revealed five major synapsin‐immunoreactive domains along the body: a large unitary, horseshoe‐shaped neuropil in the head and four neuropils in the trunk ganglia, supporting the hypothesis that the dorsal brain is serially homologous with the ventral trunk ganglia. At the same time, the pattern of anti‐synapsin and anti‐tubulin immunoreactivity differs between the ganglia, adding to the existing evidence that each of the four trunk ganglia is unique in its morphology. Anti‐tubulin labeling further revealed two commissures within the central brain neuropil, one of which is forked, and additional sets of extracerebral cephalic commissures associated with the stomodeal nervous system and the ventral cell cluster. Furthermore, our results showing the innervation of each of the cephalic sensilla in E. testudo support the homology of subsets of these structures with the sensory fields of eutardigrades. Article in Journal/Newspaper Tardigrade water bear Wiley Online Library Journal of Morphology 282 9 1298 1312 |
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Wiley Online Library |
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English |
description |
Abstract The tardigrade brain has been the topic of several neuroanatomical studies, as it is key to understanding the evolution of the central nervous systems in Panarthropoda (Tardigrada + Onychophora + Arthropoda). The gross morphology of the brain seems to be well conserved across tardigrades despite often disparate morphologies of their heads and cephalic sensory structures. As such, the general shape of the brain and its major connections to the rest of the central nervous system have been mapped out already by early tardigradologists. Despite subsequent investigations primarily based on transmission electron microscopy or immunohistochemistry, characterization of the different regions of the tardigrade brain has progressed relatively slowly and open questions remain. In an attempt to improve our understanding of different brain regions, we reinvestigated the central nervous system of the heterotardigrade Echiniscus testudo using anti‐synapsin and anti‐acetylated α‐tubulin immunohistochemistry in order to visualize the number and position of tracts, commissures, and neuropils. Our data revealed five major synapsin‐immunoreactive domains along the body: a large unitary, horseshoe‐shaped neuropil in the head and four neuropils in the trunk ganglia, supporting the hypothesis that the dorsal brain is serially homologous with the ventral trunk ganglia. At the same time, the pattern of anti‐synapsin and anti‐tubulin immunoreactivity differs between the ganglia, adding to the existing evidence that each of the four trunk ganglia is unique in its morphology. Anti‐tubulin labeling further revealed two commissures within the central brain neuropil, one of which is forked, and additional sets of extracerebral cephalic commissures associated with the stomodeal nervous system and the ventral cell cluster. Furthermore, our results showing the innervation of each of the cephalic sensilla in E. testudo support the homology of subsets of these structures with the sensory fields of eutardigrades. |
format |
Article in Journal/Newspaper |
author |
Gross, Vladimir Epple, Lisa Mayer, Georg |
spellingShingle |
Gross, Vladimir Epple, Lisa Mayer, Georg Organization of the central nervous system and innervation of cephalic sensory structures in the water bear Echiniscus testudo (Tardigrada: Heterotardigrada) revisited |
author_facet |
Gross, Vladimir Epple, Lisa Mayer, Georg |
author_sort |
Gross, Vladimir |
title |
Organization of the central nervous system and innervation of cephalic sensory structures in the water bear Echiniscus testudo (Tardigrada: Heterotardigrada) revisited |
title_short |
Organization of the central nervous system and innervation of cephalic sensory structures in the water bear Echiniscus testudo (Tardigrada: Heterotardigrada) revisited |
title_full |
Organization of the central nervous system and innervation of cephalic sensory structures in the water bear Echiniscus testudo (Tardigrada: Heterotardigrada) revisited |
title_fullStr |
Organization of the central nervous system and innervation of cephalic sensory structures in the water bear Echiniscus testudo (Tardigrada: Heterotardigrada) revisited |
title_full_unstemmed |
Organization of the central nervous system and innervation of cephalic sensory structures in the water bear Echiniscus testudo (Tardigrada: Heterotardigrada) revisited |
title_sort |
organization of the central nervous system and innervation of cephalic sensory structures in the water bear echiniscus testudo (tardigrada: heterotardigrada) revisited |
publisher |
Wiley |
publishDate |
2021 |
url |
http://dx.doi.org/10.1002/jmor.21386 https://onlinelibrary.wiley.com/doi/pdf/10.1002/jmor.21386 https://onlinelibrary.wiley.com/doi/full-xml/10.1002/jmor.21386 |
genre |
Tardigrade water bear |
genre_facet |
Tardigrade water bear |
op_source |
Journal of Morphology volume 282, issue 9, page 1298-1312 ISSN 0362-2525 1097-4687 |
op_rights |
http://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.1002/jmor.21386 |
container_title |
Journal of Morphology |
container_volume |
282 |
container_issue |
9 |
container_start_page |
1298 |
op_container_end_page |
1312 |
_version_ |
1800740414034018304 |