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Derby CD, Caprio J. What are olfaction and gustation, and do all animals have them? Chem Senses 2024; 49:bjae009. [PMID: 38422390 DOI: 10.1093/chemse/bjae009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Indexed: 03/02/2024] Open
Abstract
Different animals have distinctive anatomical and physiological properties to their chemical senses that enhance detection and discrimination of relevant chemical cues. Humans and other vertebrates are recognized as having 2 main chemical senses, olfaction and gustation, distinguished from each other by their evolutionarily conserved neuroanatomical organization. This distinction between olfaction and gustation in vertebrates is not based on the medium in which they live because the most ancestral and numerous vertebrates, the fishes, live in an aquatic habitat and thus both olfaction and gustation occur in water and both can be of high sensitivity. The terms olfaction and gustation have also often been applied to the invertebrates, though not based on homology. Consequently, any similarities between olfaction and gustation in the vertebrates and invertebrates have resulted from convergent adaptations or shared constraints during evolution. The untidiness of assigning olfaction and gustation to invertebrates has led some to recommend abandoning the use of these terms and instead unifying them and others into a single category-chemical sense. In our essay, we compare the nature of the chemical senses of diverse animal types and consider their designation as olfaction, oral gustation, extra-oral gustation, or simply chemoreception. Properties that we have found useful in categorizing chemical senses of vertebrates and invertebrates include the nature of peripheral sensory cells, organization of the neuropil in the processing centers, molecular receptor specificity, and function.
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Affiliation(s)
- Charles D Derby
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States
| | - John Caprio
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, United States
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2
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Shunkina KV, Starunova ZI, Novikova EL, Starunov VV. Mass Start or Time Trial? Structure of the Nervous System and Neuroregeneration in Pygospio elegans (Spionidae, Annelida). BIOLOGY 2023; 12:1412. [PMID: 37998011 PMCID: PMC10669057 DOI: 10.3390/biology12111412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 10/30/2023] [Accepted: 11/07/2023] [Indexed: 11/25/2023]
Abstract
The spionid worm Pygospio elegans is a convenient model for regeneration studies due to its accessibility, high tolerance, and ease of maintenance in laboratory culture. This article presents the findings regarding neuroregeneration and the structure of the nervous system based on antibody labeling of serotonin and FMRFamide. We propose the main stages of central nervous system neurogenesis during regeneration: single nerve fibers, a loop structure, and neurons in the brain and segmental ganglia. Nerve fibers and receptor cells of the peripheral nerve system can be traced to different stages of regeneration. We also provide a comparison of our results with previous data on the structure and regeneration of the nervous system based on antibody labeling of catecholamines, gamma-aminobutyric acid, and histamine and with the results for other annelids.
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Affiliation(s)
| | | | - Elena L. Novikova
- Zoological Institute RAS, Saint Petersburg 199034, Russia; (K.V.S.)
- Faculty of Biology, St. Petersburg State University, Saint Petersburg 199034, Russia
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3
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Martin C, Jahn H, Klein M, Hammel JU, Stevenson PA, Homberg U, Mayer G. The velvet worm brain unveils homologies and evolutionary novelties across panarthropods. BMC Biol 2022; 20:26. [PMID: 35073910 PMCID: PMC9136957 DOI: 10.1186/s12915-021-01196-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 11/16/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The evolution of the brain and its major neuropils in Panarthropoda (comprising Arthropoda, Tardigrada and Onychophora) remains enigmatic. As one of the closest relatives of arthropods, onychophorans are regarded as indispensable for a broad understanding of the evolution of panarthropod organ systems, including the brain, whose anatomical and functional organisation is often used to gain insights into evolutionary relations. However, while numerous recent studies have clarified the organisation of many arthropod nervous systems, a detailed investigation of the onychophoran brain with current state-of-the-art approaches is lacking, and further inconsistencies in nomenclature and interpretation hamper its understanding. To clarify the origins and homology of cerebral structures across panarthropods, we analysed the brain architecture in the onychophoran Euperipatoides rowelli by combining X-ray micro-computed tomography, histology, immunohistochemistry, confocal microscopy, and three-dimensional reconstruction. RESULTS Here, we use this detailed information to generate a consistent glossary for neuroanatomical studies of Onychophora. In addition, we report novel cerebral structures, provide novel details on previously known brain areas, and characterise further structures and neuropils in order to improve the reproducibility of neuroanatomical observations. Our findings support homology of mushroom bodies and central bodies in onychophorans and arthropods. Their antennal nerve cords and olfactory lobes most likely evolved independently. In contrast to previous reports, we found no evidence for second-order visual neuropils, or a frontal ganglion in the velvet worm brain. CONCLUSION We imaged the velvet worm nervous system at an unprecedented level of detail and compiled a comprehensive glossary of known and previously uncharacterised neuroanatomical structures to provide an in-depth characterisation of the onychophoran brain architecture. We expect that our data will improve the reproducibility and comparability of future neuroanatomical studies.
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Affiliation(s)
- Christine Martin
- Department of Zoology, Institute of Biology, University of Kassel, 34132, Kassel, Germany.
| | - Henry Jahn
- Department of Zoology, Institute of Biology, University of Kassel, 34132, Kassel, Germany
| | - Mercedes Klein
- Department of Zoology, Institute of Biology, University of Kassel, 34132, Kassel, Germany
| | - Jörg U Hammel
- Institute of Materials Physics, Helmholtz-Zentrum hereon, 21502, Geesthacht, Germany
| | - Paul A Stevenson
- Physiology of Animals and Behaviour, Institute of Biology, University of Leipzig, 04103, Leipzig, Germany
| | - Uwe Homberg
- Department of Biology, Animal Physiology, Philipps-Universität Marburg, 35043, Marburg, Germany
- Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus Liebig University Giessen, 35032, Marburg, Germany
| | - Georg Mayer
- Department of Zoology, Institute of Biology, University of Kassel, 34132, Kassel, Germany.
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Abstract
AbstractMushroom bodies are known from annelids and arthropods and were formerly assumed to argue for a close relationship of these two taxa. Since molecular phylogenies univocally show that both taxa belong to two different clades in the bilaterian tree, similarity must either result from convergent evolution or from transformation of an ancestral mushroom body. Any morphological differences in the ultrastructure and composition of mushroom bodies could thus indicate convergent evolution that results from similar functional constraints. We here study the ultrastructure of the mushroom bodies, the glomerular neuropil, glia-cells and the general anatomy of the nervous system in Sthenelais boa. The neuropil of the mushroom bodies is composed of densely packed, small diameter neurites that lack individual or clusterwise glia enwrapping. Neurites of other regions of the brain are much more prominent, are enwrapped by glia-cell processes and thus can be discriminated from the neuropil of the mushroom bodies. The same applies to the respective neuronal somata. The glomerular neuropil of insects and annelids is a region of higher synaptic activity that result in a spheroid appearance of these structures. However, while these structures are sharply delimited from the surrounding neuropil of the brain by glia enwrapping in insects, this is not the case in Sthenelais boa. Although superficially similar, there are anatomical differences in the arrangement of glia-cells in the mushroom bodies and the glomerular neuropil between insects and annelids. Hence, we suppose that the observed differences rather evolved convergently to solve similar functional constrains than by transforming an ancestral mushroom body design.
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Gąsiorowski L, Børve A, Cherneva IA, Orús-Alcalde A, Hejnol A. Molecular and morphological analysis of the developing nemertean brain indicates convergent evolution of complex brains in Spiralia. BMC Biol 2021; 19:175. [PMID: 34452633 PMCID: PMC8400761 DOI: 10.1186/s12915-021-01113-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 07/30/2021] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND The brain anatomy in the clade Spiralia can vary from simple, commissural brains (e.g., gastrotrichs, rotifers) to rather complex, partitioned structures (e.g., in cephalopods and annelids). How often and in which lineages complex brains evolved still remains unclear. Nemerteans are a clade of worm-like spiralians, which possess a complex central nervous system (CNS) with a prominent brain, and elaborated chemosensory and neuroglandular cerebral organs, which have been previously suggested as homologs to the annelid mushroom bodies. To understand the developmental and evolutionary origins of the complex brain in nemerteans and spiralians in general, we investigated details of the neuroanatomy and gene expression in the brain and cerebral organs of the juveniles of nemertean Lineus ruber. RESULTS In the juveniles, the CNS is already composed of all major elements present in the adults, including the brain, paired longitudinal lateral nerve cords, and an unpaired dorsal nerve cord, which suggests that further neural development is mostly related with increase in the size but not in complexity. The ultrastructure of the juvenile cerebral organ revealed that it is composed of several distinct cell types present also in the adults. The 12 transcription factors commonly used as brain cell type markers in bilaterians show region-specific expression in the nemertean brain and divide the entire organ into several molecularly distinct areas, partially overlapping with the morphological compartments. Additionally, several of the mushroom body-specific genes are expressed in the developing cerebral organs. CONCLUSIONS The dissimilar expression of molecular brain markers between L. ruber and the annelid Platynereis dumerilii indicates that the complex brains present in those two species evolved convergently by independent expansions of non-homologous regions of a simpler brain present in their last common ancestor. Although the same genes are expressed in mushroom bodies and cerebral organs, their spatial expression within organs shows apparent differences between annelids and nemerteans, indicating convergent recruitment of the same genes into patterning of non-homologous organs or hint toward a more complicated evolutionary process, in which conserved and novel cell types contribute to the non-homologous structures.
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Affiliation(s)
| | - Aina Børve
- Department of Biological Sciences, University of Bergen, Bergen, Norway
| | - Irina A Cherneva
- Biological Faculty, M.V. Lomonosov Moscow State University, Moscow, Russia
| | | | - Andreas Hejnol
- Department of Biological Sciences, University of Bergen, Bergen, Norway.
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Whole-body integration of gene expression and single-cell morphology. Cell 2021; 184:4819-4837.e22. [PMID: 34380046 PMCID: PMC8445025 DOI: 10.1016/j.cell.2021.07.017] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 05/05/2021] [Accepted: 07/14/2021] [Indexed: 01/10/2023]
Abstract
Animal bodies are composed of cell types with unique expression programs that implement their distinct locations, shapes, structures, and functions. Based on these properties, cell types assemble into specific tissues and organs. To systematically explore the link between cell-type-specific gene expression and morphology, we registered an expression atlas to a whole-body electron microscopy volume of the nereid Platynereis dumerilii. Automated segmentation of cells and nuclei identifies major cell classes and establishes a link between gene activation, chromatin topography, and nuclear size. Clustering of segmented cells according to gene expression reveals spatially coherent tissues. In the brain, genetically defined groups of neurons match ganglionic nuclei with coherent projections. Besides interneurons, we uncover sensory-neurosecretory cells in the nereid mushroom bodies, which thus qualify as sensory organs. They furthermore resemble the vertebrate telencephalon by molecular anatomy. We provide an integrated browser as a Fiji plugin for remote exploration of all available multimodal datasets. A cellular atlas integrates gene expression and ultrastructure for an entire annelid Morphometry of all segmented cells, nuclei, and chromatin categorizes cell classes Molecular anatomy and projectome of head ganglionic nuclei and mushroom bodies An open-source browser for multimodal big image data exploration and analysis
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7
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Affiliation(s)
- Patrick Beckers
- Institute of Evolutionary Biology and Ecology University of Bonn Bonn Germany
| | - Ekin Tilic
- Institute of Evolutionary Biology and Ecology University of Bonn Bonn Germany
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Schmidbaur H, Schwaha T, Franzkoch R, Purschke G, Steiner G. Within-family plasticity of nervous system architecture in Syllidae (Annelida, Errantia). Front Zool 2020; 17:20. [PMID: 32582362 PMCID: PMC7310387 DOI: 10.1186/s12983-020-00359-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 04/03/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The ground pattern underlying the nervous system of the last common ancestor in annelids was long thought to be settled, consisting of a dorsal brain, circumoesophageal connectives and a subepithelial, ladder-like ventral nerve cord with segmental ganglia connected by paired connectives. With the advent of immunocytochemical stainings and confocal laser scanning microscopy, it becomes evident that its architecture is extremely diverse, which makes the reconstruction of a ground pattern in annelida challenging. Whereas the nervous systems of many different families has already been described, only very few studies looked at the diversity of nervous systems within such clades to give a closer estimate on how plastic the annelid nervous system really is. So far, little is known on syllid nervous system architecture, one of the largest and most diverse groups of marine annelids. RESULTS The position of the brain, the circumoesophageal connectives, the stomatogastric nervous system, the longitudinal nerves that traverse each segment and the innervation of appendages are relatively uniform within the clade. Both the number of connectives within the ventral nerve cord and the number of segmental nerves, which in earlier studies were used to infer phylogenetic relationships and to reconstruct an annelid ground pattern, are highly diverse and differ between genera or even within a given genus. Differences in the distribution of somata of the brain, the nuchal innervation and its associated cell bodies were found between Syllinae and Exogoninae and may be subfamily-specific. CONCLUSIONS The nervous system morphology of syllids very likely depends on the taxon-specific ecological requirements. Thus, it is not surprising that in a clade, which occupies such diverse niches as the Annelida, we find similar patterns in phylogenetically widely separated species in similar niches and a high degree of modularity within a family. Only standardized protocols and staining methods can lead to comparable results, but so far different approaches have been taken to describe annelid nervous systems, making homologization of certain structures difficult. This study provides the first thorough description of the nervous system in the family Syllidae, allowing more detailed comparisons between annelid families in the future.
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Affiliation(s)
- Hannah Schmidbaur
- Department of Integrative Zoology, Faculty of Life Sciences, University of Vienna, Althanstraße 14, 1090 Vienna, Austria
- Present address: Department of Molecular Evolution and Development, Faculty of Life Sciences, University of Vienna, Althanstraße 14, 1090 Vienna, Austria
| | - Thomas Schwaha
- Department of Integrative Zoology, Faculty of Life Sciences, University of Vienna, Althanstraße 14, 1090 Vienna, Austria
| | - Rico Franzkoch
- Zoology and Developmental Biology, Department of Biology and Chemistry, University of Osnabrück, Barbarastr. 11, 49069 Osnabrück, Germany
- Present address: Microbiology, Department of Biology and Chemistry, University of Osnabrück, Barbarastr. 11, 49069 Osnabrück, Germany
| | - Günter Purschke
- Zoology and Developmental Biology, Department of Biology and Chemistry, University of Osnabrück, Barbarastr. 11, 49069 Osnabrück, Germany
| | - Gerhard Steiner
- Department of Integrative Zoology, Faculty of Life Sciences, University of Vienna, Althanstraße 14, 1090 Vienna, Austria
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Nanglu K, Caron JB. A New Burgess Shale Polychaete and the Origin of the Annelid Head Revisited. Curr Biol 2019; 28:319-326.e1. [PMID: 29374441 DOI: 10.1016/j.cub.2017.12.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 09/11/2017] [Accepted: 12/08/2017] [Indexed: 11/28/2022]
Abstract
Annelida is one of the most speciose (∼17,000 species) and ecologically successful phyla. Key to this success is their flexible body plan with metameric trunk segments and bipartite heads consisting of a prostomium bearing sensory structures and a peristomium containing the mouth. The flexibility of this body plan has traditionally proven problematic for reconstructing the evolutionary relationships within the Annelida. Although recent phylogenies have focused on resolving the interrelationships of the crown group [1-3], many questions remain regarding the early evolution of the annelid body plan itself, including the origin of the head [4]. Here we describe an abundant and exceptionally well-preserved polychaete with traces of putative neural and vascular tissues for the first time in a fossilized annelid. Up to three centimeters in length, Kootenayscolex barbarensis gen. et sp. nov. is described based on more than 500 specimens from Marble Canyon [5] and several specimens from the original Burgess Shale site (both in British Columbia, Canada). K. barbarensis possesses biramous parapodia along the trunk, bearing similar elongate and thin notochaetae and neurochaetae. A pair of large palps and one median antenna project from the anteriormost dorsal margin of the prostomium. The mouth-bearing peristomium bears neuropodial chaetae, a condition that is also inferred in Canadia and Burgessochaeta from the Burgess Shale, suggesting a chaetigorous origin for the peristomial portion of the head and a secondary loss of peristomial parapodia and chaetae in modern polychaetes.
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Affiliation(s)
- Karma Nanglu
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON M5S 2J7, Canada.
| | - Jean-Bernard Caron
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON M5S 2J7, Canada; Department of Natural History Palaeobiology, Royal Ontario Museum, Toronto, ON M5S 2C6, Canada; Department of Earth Sciences, University of Toronto, Toronto, ON M5S 3B1, Canada
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Beckers P, Helm C, Purschke G, Worsaae K, Hutchings P, Bartolomaeus T. The central nervous system of Oweniidae (Annelida) and its implications for the structure of the ancestral annelid brain. Front Zool 2019; 16:6. [PMID: 30911320 PMCID: PMC6417257 DOI: 10.1186/s12983-019-0305-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 02/26/2019] [Indexed: 11/29/2022] Open
Abstract
Background Recent phylogenomic analyses congruently reveal a basal clade which consists of Oweniidae and Mageloniidae as sister group to the remaining Annelida. These results indicate that the last common ancestor of Annelida was a tube-dwelling organism. They also challenge traditional evolutionary hypotheses of different organ systems, among them the nervous system. In textbooks the central nervous system is described as consisting of a ganglionic ventral nervous system and a dorsally located brain with different tracts that connect certain parts of the brain to each other. Only limited information on the fine structure, however, is available for Oweniidae, which constitute the sister group (possibly together with Magelonidae) to all remaining annelids. Results The brain of Oweniidae is ring- shaped and basiepidermal. Ganglia, higher brain centers or complex sensory organs do not exist; instead the central nervous system is medullary. Posterior to the brain the ventral medullary cord arises directly from the ventral region of the brain in Myriowenia sp. while in Owenia fusiformis two medullary cords arise perpendicular to the brain ring, extend caudally and fuse posterior. The central nervous system is composed of a central neuropil and surrounding somata of the neurons. According to ultrastructural and histological data only one type of neuron is present in the central nervous system. Conclusion The central nervous system of Oweniidae is the simplest in terms of enlargement of the dorsal part of the brain and neuron distribution found among Annelida. Our investigation suggests that neither ganglia nor commissures inside the brain neuropil or clusters of polymorphic neurons were present in the annelid stem species. These structures evolved later within Annelida, most likely in the stem lineage of Amphinomidae, Sipuncula and Pleistoannelida. Palps were supposedly present in the last common ancestor of annelids and innervated by two nerves originating in the dorsal part of the brain. A broader comparison with species of each major spiralian clade shows the medullary nervous system to be a common feature and thus possibly representing the ancestral state of the spiralian nervous system. Moreover, ganglia and clusters of polymorphic neurons seemingly evolved independently in the compared taxa of Spiralia and Annelida. Electronic supplementary material The online version of this article (10.1186/s12983-019-0305-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Patrick Beckers
- 1Institute of Evolutionary Biology, University of Bonn, 53121 Bonn, Germany
| | - Conrad Helm
- 2Johann-Friedrich-Blumenbach Institute for Zoology & Anthropology Animal Evolution and Biodiversity, University of Göttingen, 37073 Göttingen, Germany
| | - Günter Purschke
- 3Department of Developmental Biology and Zoology, University of Osnabrück, 49069 Osnabrück, Germany
| | - Katrine Worsaae
- 4Department of Biology, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Pat Hutchings
- 5Australian Museum Research Institute, Australian Museum, Sydney, NSW 2010 Australia.,6Department of Biological Sciences, Macquarie University, North Ryde, 2109 Australia
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Starunov VV. The organization of musculature and the nervous system in the pygidial region of phyllodocid annelids. ZOOMORPHOLOGY 2019. [DOI: 10.1007/s00435-018-00430-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Rimskaya-Korsakova NN, Galkin SV, Malakhov VV. The neuroanatomy of the siboglinid Riftia pachyptila highlights sedentarian annelid nervous system evolution. PLoS One 2018; 13:e0198271. [PMID: 30543637 PMCID: PMC6292602 DOI: 10.1371/journal.pone.0198271] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 11/24/2018] [Indexed: 12/28/2022] Open
Abstract
Tracing the evolution of the siboglinid group, peculiar group of marine gutless annelids, requires the detailed study of the fragmentarily explored central nervous system of vestimentiferans and other siboglinids. 3D reconstructions of the neuroanatomy of Riftia revealed that the "brain" of adult vestimentiferans is a fusion product of the supraesophageal and subesophageal ganglia. The supraesophageal ganglion-like area contains the following neural structures that are homologous to the annelid elements: the peripheral perikarya of the brain lobes, two main transverse commissures, mushroom-like structures, commissural cell cluster, and the circumesophageal connectives with two roots which give rise to the palp neurites. Three pairs of giant perikarya are located in the supraesophageal ganglion, giving rise to the paired giant axons. The circumesophageal connectives run to the VNC. The subesophageal ganglion-like area contains a tripartite ventral aggregation of perikarya (= the postoral ganglion of the VNC) interconnected by the subenteral commissure. The paired VNC is intraepidermal, not ganglionated over most of its length, associated with the ciliary field, and comprises the giant axons. The pairs of VNC and the giant axons fuse posteriorly. Within siboglinids, the vestimentiferans are distinguished by a large and considerably differentiated brain. This reflects the derived development of the tentacle crown. The tentacles of vestimentiferans are homologous to the annelid palps based on their innervation from the dorsal and ventral roots of the circumesophageal connectives. Neuroanatomy of the vestimentiferan brains is close to the brains of Cirratuliiformia and Spionida/Sabellida, which have several transverse commissures, specific position of the giant somata (if any), and palp nerve roots (if any). The palps and palp neurite roots originally developed in all main annelid clades (basally branching, errantian and sedentarian annelids), show the greatest diversity in their number in sedentarian species. Over the course of evolution of Sedentaria, the number of palps and their nerve roots either dramatically increased (as in vestimentiferan siboglinids) or were lost.
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Affiliation(s)
| | - Sergey V. Galkin
- Laboratory of Ocean Benthic Fauna, Shirshov Institute of Oceanology of the Russian Academy of Science, Moscow, Russia
| | - Vladimir V. Malakhov
- Department of Invertebrate Zoology, Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia
- Far Eastern Federal University, Vladivostok, Russia
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Chartier TF, Deschamps J, Dürichen W, Jékely G, Arendt D. Whole-head recording of chemosensory activity in the marine annelid Platynereis dumerilii. Open Biol 2018; 8:180139. [PMID: 30381362 PMCID: PMC6223215 DOI: 10.1098/rsob.180139] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 10/08/2018] [Indexed: 01/13/2023] Open
Abstract
Chemical detection is key to various behaviours in both marine and terrestrial animals. Marine species, though highly diverse, have been underrepresented so far in studies on chemosensory systems, and our knowledge mostly concerns the detection of airborne cues. A broader comparative approach is therefore desirable. Marine annelid worms with their rich behavioural repertoire represent attractive models for chemosensation. Here, we study the marine worm Platynereis dumerilii to provide the first comprehensive investigation of head chemosensory organ physiology in an annelid. By combining microfluidics and calcium imaging, we record neuronal activity in the entire head of early juveniles upon chemical stimulation. We find that Platynereis uses four types of organs to detect stimuli such as alcohols, esters, amino acids and sugars. Antennae are the main chemosensory organs, compared to the more differentially responding nuchal organs or palps. We report chemically evoked activity in possible downstream brain regions including the mushroom bodies (MBs), which are anatomically and molecularly similar to insect MBs. We conclude that chemosensation is a major sensory modality for marine annelids and propose early Platynereis juveniles as a model to study annelid chemosensory systems.
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Affiliation(s)
- Thomas F Chartier
- Developmental Biology Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Joran Deschamps
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Wiebke Dürichen
- Developmental Biology Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Gáspár Jékely
- Living Systems Institute, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
| | - Detlev Arendt
- Developmental Biology Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117 Heidelberg, Germany
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14
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Evolution of the bilaterian mouth and anus. Nat Ecol Evol 2018; 2:1358-1376. [PMID: 30135501 DOI: 10.1038/s41559-018-0641-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 06/26/2018] [Accepted: 07/11/2018] [Indexed: 12/17/2022]
Abstract
It is widely held that the bilaterian tubular gut with mouth and anus evolved from a simple gut with one major gastric opening. However, there is no consensus on how this happened. Did the single gastric opening evolve into a mouth, with the anus forming elsewhere in the body (protostomy), or did it evolve into an anus, with the mouth forming elsewhere (deuterostomy), or did it evolve into both mouth and anus (amphistomy)? These questions are addressed by the comparison of developmental fates of the blastopore, the opening of the embryonic gut, in diverse animals that live today. Here we review comparative data on the identity and fate of blastoporal tissue, investigate how the formation of the through-gut relates to the major body axes, and discuss to what extent evolutionary scenarios are consistent with these data. Available evidence indicates that stem bilaterians had a slit-like gastric opening that was partially closed in subsequent evolution, leaving open the anus and most likely also the mouth, which would favour amphistomy. We discuss remaining difficulties, and outline directions for future research.
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Scaros AT, Croll RP, Baratte S. Immunohistochemical Approach to Understanding the Organization of the Olfactory System in the Cuttlefish, Sepia officinalis. ACS Chem Neurosci 2018; 9:2074-2088. [PMID: 29578683 DOI: 10.1021/acschemneuro.8b00021] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Cephalopods are nontraditional but captivating models of invertebrate neurobiology, particularly in evolutionary comparisons. Cephalopod olfactory systems have striking similarities and fundamental differences with vertebrates, arthropods, and gastropods, raising questions about the ancestral origins of those systems. We describe here the organization and development of the olfactory system of the common cuttlefish, Sepia officinalis, using immunohistochemistry and in situ hybridization. FMRFamide and/or related peptides and histamine are putative neurotransmitters in olfactory sensory neurons. Other neurotransmitters, including serotonin and APGWamide within the olfactory and other brain lobes, suggest efferent control of olfactory input and/or roles in the processing of olfactory information. The distributions of neurotransmitters, along with staining patterns of phalloidin, anti-acetylated α-tubulin, and a synaptotagmin riboprobe, help to clarify the structure of the olfactory lobe. We discuss a key difference, the lack of identifiable olfactory glomeruli, in cuttlefish in comparison to other models, and suggest its implications for the evolution of olfaction.
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Affiliation(s)
- Alexia T. Scaros
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Roger P. Croll
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Sébastien Baratte
- Sorbonne Université,
MNHN, UNICAEN, UA, CNRS, IRD, Biologie des Organismes et Ecosystèmes
Aquatiques (BOREA), Paris 75005, France
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16
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Kerbl A, Conzelmann M, Jékely G, Worsaae K. High diversity in neuropeptide immunoreactivity patterns among three closely related species of Dinophilidae (Annelida). J Comp Neurol 2017; 525:3596-3635. [PMID: 28744909 DOI: 10.1002/cne.24289] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 06/23/2017] [Accepted: 07/07/2017] [Indexed: 12/31/2022]
Abstract
Neuropeptides are conserved metazoan signaling molecules, and represent useful markers for comparative investigations on the morphology and function of the nervous system. However, little is known about the variation of neuropeptide expression patterns across closely related species in invertebrate groups other than insects. In this study, we compare the immunoreactivity patterns of 14 neuropeptides in three closely related microscopic dinophilid annelids (Dinophilus gyrociliatus, D. taeniatus and Trilobodrilus axi). The brains of all three species were found to consist of around 700 somata, surrounding a central neuropil with 3-5 ventral and 2-5 dorsal commissures. Neuropeptide immunoreactivity was detected in the brain, the ventral cords, stomatogastric nervous system, and additional nerves. Different neuropeptides are expressed in specific, non-overlapping cells in the brain in all three species. FMRFamide, MLD/pedal peptide, allatotropin, RNamide, excitatory peptide, and FVRIamide showed a broad localization within the brain, while calcitonin, SIFamide, vasotocin, RGWamide, DLamide, FLamide, FVamide, MIP, and serotonin were present in fewer cells in demarcated regions. The different markers did not reveal ganglionic subdivisions or physical compartmentalization in any of these microscopic brains. The non-overlapping expression of different neuropeptides may indicate that the regionalization in these uniform, small brains is realized by individual cells, rather than cell clusters, representing an alternative to the lobular organization observed in several macroscopic annelids. Furthermore, despite the similar gross brain morphology, we found an unexpectedly high variation in the expression patterns of neuropeptides across species. This suggests that neuropeptide expression evolves faster than morphology, representing a possible mechanism for the evolutionary divergence of behaviors.
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Affiliation(s)
- Alexandra Kerbl
- Marine Biological Section - Department of Biology, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | | | - Gáspár Jékely
- Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Katrine Worsaae
- Marine Biological Section - Department of Biology, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
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17
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Thoen HH, Marshall J, Wolff GH, Strausfeld NJ. Insect-Like Organization of the Stomatopod Central Complex: Functional and Phylogenetic Implications. Front Behav Neurosci 2017; 11:12. [PMID: 28223924 PMCID: PMC5294995 DOI: 10.3389/fnbeh.2017.00012] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 01/13/2017] [Indexed: 11/17/2022] Open
Abstract
One approach to investigating functional attributes of the central complex is to relate its various elaborations to pancrustacean phylogeny, to taxon-specific behavioral repertoires and ecological settings. Here we review morphological similarities between the central complex of stomatopod crustaceans and the central complex of dicondylic insects. We discuss whether their central complexes possess comparable functional properties, despite the phyletic distance separating these taxa, with mantis shrimp (Stomatopoda) belonging to the basal branch of Eumalacostraca. Stomatopods possess the most elaborate visual receptor system in nature and display a fascinating behavioral repertoire, including refined appendicular dexterity such as independently moving eyestalks. They are also unparalleled in their ability to maneuver during both swimming and substrate locomotion. Like other pancrustaceans, stomatopods possess a set of midline neuropils, called the central complex, which in dicondylic insects have been shown to mediate the selection of motor actions for a range of behaviors. As in dicondylic insects, the stomatopod central complex comprises a modular protocerebral bridge (PB) supplying decussating axons to a scalloped fan-shaped body (FB) and its accompanying ellipsoid body (EB), which is linked to a set of paired noduli and other recognized satellite regions. We consider the functional implications of these attributes in the context of stomatopod behaviors, particularly of their eyestalks that can move independently or conjointly depending on the visual scene.
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Affiliation(s)
- Hanne H Thoen
- Sensory Neurobiology Group, Queensland Brain Institute, University of Queensland, St. Lucia Brisbane, QLD, Australia
| | - Justin Marshall
- Sensory Neurobiology Group, Queensland Brain Institute, University of Queensland, St. Lucia Brisbane, QLD, Australia
| | | | - Nicholas J Strausfeld
- Department of Neuroscience, School of Mind, Brain and Behavior, University of Arizona Tucson, AZ, USA
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18
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Kerbl A, Martín-Durán JM, Worsaae K, Hejnol A. Molecular regionalization in the compact brain of the meiofaunal annelid Dinophilus gyrociliatus (Dinophilidae). EvoDevo 2016; 7:20. [PMID: 27583125 PMCID: PMC5006589 DOI: 10.1186/s13227-016-0058-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 08/17/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Annelida is a morphologically diverse animal group that exhibits a remarkable variety in nervous system architecture (e.g., number and location of longitudinal cords, architecture of the brain). Despite this heterogeneity of neural arrangements, the molecular profiles related to central nervous system patterning seem to be conserved even between distantly related annelids. In particular, comparative molecular studies on brain and anterior neural region patterning genes have focused so far mainly on indirect-developing macrofaunal taxa. Therefore, analyses on microscopic, direct-developing annelids are important to attain a general picture of the evolutionary events underlying the vast diversity of annelid neuroanatomy. RESULTS We have analyzed the expression domains of 11 evolutionarily conserved genes involved in brain and anterior neural patterning in adult females of the direct-developing meiofaunal annelid Dinophilus gyrociliatus. The small, compact brain shows expression of dimmed, foxg, goosecoid, homeobrain, nk2.1, orthodenticle, orthopedia, pax6, six3/6 and synaptotagmin-1. Although most of the studied markers localize to specific brain areas, the genes six3/6 and synaptotagmin-1 are expressed in nearly all perikarya of the brain. All genes except for goosecoid, pax6 and nk2.2 overlap in the anterior brain region, while the respective expression domains are more separated in the posterior brain. CONCLUSIONS Our findings reveal that the expression patterns of the genes foxg, orthodenticle, orthopedia and six3/6 correlate with those described in Platynereis dumerilii larvae, and homeobrain, nk2.1, orthodenticle and synaptotagmin-1 resemble the pattern of late larvae of Capitella teleta. Although data on other annelids are limited, molecular similarities between adult Dinophilus and larval Platynereis and Capitella suggest an overall conservation of molecular mechanisms patterning the anterior neural regions, independent from developmental and ecological strategies, or of the size and configuration of the nervous system.
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Affiliation(s)
- Alexandra Kerbl
- Marine Biology Section, Department of Biology, Faculty of Science, University of Copenhagen, Universitetsparken 4, 2100 Copenhagen, Denmark
| | - José M Martín-Durán
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate, 55, 5006 Bergen, Norway
| | - Katrine Worsaae
- Marine Biology Section, Department of Biology, Faculty of Science, University of Copenhagen, Universitetsparken 4, 2100 Copenhagen, Denmark
| | - Andreas Hejnol
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate, 55, 5006 Bergen, Norway
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19
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Schumann I, Hering L, Mayer G. Immunolocalization of Arthropsin in the Onychophoran Euperipatoides rowelli (Peripatopsidae). Front Neuroanat 2016; 10:80. [PMID: 27540356 PMCID: PMC4972820 DOI: 10.3389/fnana.2016.00080] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Accepted: 07/14/2016] [Indexed: 01/09/2023] Open
Abstract
Opsins are light-sensitive proteins that play a key role in animal vision and are related to the ancient photoreceptive molecule rhodopsin found in unicellular organisms. In general, opsins involved in vision comprise two major groups: the rhabdomeric (r-opsins) and the ciliary opsins (c-opsins). The functionality of opsins, which is dependent on their protein structure, may have changed during evolution. In arthropods, typically r-opsins are responsible for vision, whereas in vertebrates c-opsins are components of visual photoreceptors. Recently, an enigmatic r-opsin-like protein called arthropsin has been identified in various bilaterian taxa, including arthropods, lophotrochozoans, and chordates, by performing transcriptomic and genomic analyses. Since the role of arthropsin and its distribution within the body are unknown, we immunolocalized this protein in a representative of Onychophora – Euperipatoides rowelli – an ecdysozoan taxon which is regarded as one of the closest relatives of Arthropoda. Our data show that arthropsin is expressed in the central nervous system of E. rowelli, including the brain and the ventral nerve cords, but not in the eyes. These findings are consistent with previous results based on reverse transcription PCR in a closely related onychophoran species and suggest that arthropsin is a non-visual protein. Based on its distribution in the central brain region and the mushroom bodies, we speculate that the onychophoran arthropsin might be either a photosensitive molecule playing a role in the circadian clock, or a non-photosensitive protein involved in olfactory pathways, or both.
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Affiliation(s)
- Isabell Schumann
- Department of Zoology, Institute of Biology, University of Kassel, KasselGermany; Molecular Evolution and Animal Systematics, University of Leipzig, LeipzigGermany
| | - Lars Hering
- Department of Zoology, Institute of Biology, University of Kassel, Kassel Germany
| | - Georg Mayer
- Department of Zoology, Institute of Biology, University of Kassel, Kassel Germany
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20
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Olfactory pathway in Xibalbanus tulumensis: remipedian hemiellipsoid body as homologue of hexapod mushroom body. Cell Tissue Res 2015; 363:635-48. [PMID: 26358175 DOI: 10.1007/s00441-015-2275-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 08/04/2015] [Indexed: 01/01/2023]
Abstract
The Remipedia have been proposed to be the crustacean sister group of the Hexapoda. These blind cave animals heavily rely on their chemical sense and are thus rewarding subjects for the analysis of olfactory pathways. The evolution of these pathways as a character for arthropod phylogeny has recently received increasing attention. Here, we investigate the situation in Xibalbanus tulumensis by focal dye injections and immunolabelling of the catalytic subunit of the cAMP-dependent protein kinase (DC0), an enzyme particularly enriched in insect mushroom bodies. DC0 labelling of the hemiellipsoid body suggests its subdivision into a cap-like and a core neuropil. Immunofluorescence of the enzyme glutamic acid decarboxylase (GAD), which synthesizes γ-aminobutyric acid (GABA), has revealed a cluster of GABAergic interneurons in the hemiellipsoid body, reminiscent of the characteristic feedback neurons of the mushroom body. Thus, the hemiellipsoid body of Xibalbanus shares many of the characteristics of insect mushroom bodies. Nevertheless, the general neuroanatomy of the olfactory pathway in the Remipedia strongly corresponds to the malacostracan ground pattern. Given that the Remipedia are probably the sister group of the Hexapoda, the phylogenetic appearance of the typical neuropilar compartments in the insect mushroom body has to be assigned to the origins of the Hexapoda.
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21
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Meyer NP, Carrillo-Baltodano A, Moore RE, Seaver EC. Nervous system development in lecithotrophic larval and juvenile stages of the annelid Capitella teleta. Front Zool 2015; 12:15. [PMID: 26167198 PMCID: PMC4498530 DOI: 10.1186/s12983-015-0108-y] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Accepted: 05/20/2015] [Indexed: 11/24/2022] Open
Abstract
Background Reconstructing the evolutionary history of nervous systems requires an understanding of their architecture and development across diverse taxa. The spiralians encompass diverse body plans and organ systems, and within the spiralians, annelids exhibit a variety of morphologies, life histories, feeding modes and associated nervous systems, making them an ideal group for studying evolution of nervous systems. Results We describe nervous system development in the annelid Capitella teleta (Blake JA, Grassle JP, Eckelbarger KJ. Capitella teleta, a new species designation for the opportunistic and experimental Capitella sp. I, with a review of the literature for confirmed records. Zoosymposia. 2009;2:25–53) using whole-mount in situ hybridization for a synaptotagmin 1 homolog, nuclear stains, and cross-reactive antibodies against acetylated α-tubulin, 5-HT and FMRFamide. Capitella teleta is member of the Sedentaria (Struck TH, Paul C, Hill N, Hartmann S, Hosel C, Kube M, et al. Phylogenomic analyses unravel annelid evolution. Nature. 2011;471:95–8) and has an indirectly-developing, lecithotrophic larva. The nervous system of C. teleta shares many features with other annelids, including a brain and a ladder-like ventral nerve cord with five connectives, reiterated commissures, and pairs of peripheral nerves. Development of the nervous system begins with the first neurons differentiating in the brain, and follows a temporal order from central to peripheral and from anterior to posterior. Similar to other annelids, neurons with serotonin-like-immunoreactivity (5HT-LIR) and FMRFamide-like-immunoreactivity (FMRF-LIR) are found throughout the brain and ventral nerve cord. A small number of larval-specific neurons and neurites are present, but are visible only after the central nervous system begins to form. These larval neurons are not visible after metamorphosis while the rest of the nervous system is largely unchanged in juveniles. Conclusions Most of the nervous system that forms during larvogenesis in C. teleta persists into the juvenile stage. The first neurons differentiate in the brain, which contrasts with the early formation of peripheral, larval-specific neurons found in some spiralian taxa with planktotrophic larvae. Our study provides a clear indication that certain shared features among annelids - e.g., five connectives in the ventral nerve cord - are only visible during larval stages in particular species, emphasizing the need to include developmental data in ancestral character state reconstructions. The data provided in this paper will serve as an important comparative reference for understanding evolution of nervous systems, and as a framework for future molecular studies of development. Electronic supplementary material The online version of this article (doi:10.1186/s12983-015-0108-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Néva P Meyer
- Biology Department, Clark University, 950 Main Street, Worcester, MA 01610 USA
| | | | - Richard E Moore
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, 1955 East-west Road, Honolulu, HI 96822 USA
| | - Elaine C Seaver
- Whitney Laboratory for Marine Bioscience, University of Florida, 9505 Ocean Shore Boulevard, Saint Augustine, FL 32080 USA
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22
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Shigeno S, Ogura A, Mori T, Toyohara H, Yoshida T, Tsuchida S, Fujikura K. Sensing deep extreme environments: the receptor cell types, brain centers, and multi-layer neural packaging of hydrothermal vent endemic worms. Front Zool 2014; 11:82. [PMID: 25505488 PMCID: PMC4261566 DOI: 10.1186/s12983-014-0082-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 10/23/2014] [Indexed: 01/30/2023] Open
Abstract
INTRODUCTION Deep-sea alvinellid worm species endemic to hydrothermal vents, such as Alvinella and Paralvinella, are considered to be among the most thermotolerant animals known with their adaptability to toxic heavy metals, and tolerance of highly reductive and oxidative stressful environments. Despite the number of recent studies focused on their overall transcriptomic, proteomic, and metabolic stabilities, little is known regarding their sensory receptor cells and electrically active neuro-processing centers, and how these can tolerate and function in such harsh conditions. RESULTS We examined the extra- and intracellular organizations of the epidermal ciliated sensory cells and their higher centers in the central nervous system through immunocytochemical, ultrastructural, and neurotracing analyses. We observed that these cells were rich in mitochondria and possessed many electron-dense granules, and identified specialized glial cells and serial myelin-like repeats in the head sensory systems of Paralvinella hessleri. Additionally, we identified the major epidermal sensory pathways, in which a pair of distinct mushroom bodies-like or small interneuron clusters was observed. These sensory learning and memory systems are commonly found in insects and annelids, but the alvinellid inputs are unlikely derived from the sensory ciliary cells of the dorsal head regions. CONCLUSIONS Our evidence provides insight into the cellular and system-wide adaptive structure used to sense, process, and combat the deep-sea hydrothermal vent environment. The alvinellid sensory cells exhibit characteristics of annelid ciliary types, and among the most unique features were the head sensory inputs and structure of the neural cell bodies of the brain, which were surrounded by multiple membranes. We speculated that such enhanced protection is required for the production of normal electrical signals, and to avoid the breakdown of the membrane surrounding metabolically fragile neurons from oxidative stress. Such pivotal acquisition is not broadly found in the all body parts, suggesting the head sensory inputs are specific, and these heterogenetic protection mechanisms may be present in alvinellid worms.
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Affiliation(s)
- Shuichi Shigeno
- Department for Marine Biodiversity Research, Japan Agency for Marine-Earth Science and Technology, 2-15 Natsushima-cho, Yokosuka, 237-0061, Kanagawa Japan
| | - Atsushi Ogura
- Nagahama Institute of Bio-Science and Technology, Institute of Bio-Science and Technology, 1266 Tamura-Cho, Nagahama, 526-0829, Shiga Japan
| | - Tsukasa Mori
- Nihon University, 1866 Kameino, Fujisawa, 252-0880, Kanagawa Japan
| | - Haruhiko Toyohara
- Division of Applied Biosciences, Kyoto University, Graduate School of Agriculture, Laboratory of Marine Biological Function, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8602 Japan
| | - Takao Yoshida
- Department for Marine Biodiversity Research, Japan Agency for Marine-Earth Science and Technology, 2-15 Natsushima-cho, Yokosuka, 237-0061, Kanagawa Japan
| | - Shinji Tsuchida
- Department for Marine Biodiversity Research, Japan Agency for Marine-Earth Science and Technology, 2-15 Natsushima-cho, Yokosuka, 237-0061, Kanagawa Japan
| | - Katsunori Fujikura
- Department for Marine Biodiversity Research, Japan Agency for Marine-Earth Science and Technology, 2-15 Natsushima-cho, Yokosuka, 237-0061, Kanagawa Japan
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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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Holland LZ, Carvalho JE, Escriva H, Laudet V, Schubert M, Shimeld SM, Yu JK. Evolution of bilaterian central nervous systems: a single origin? EvoDevo 2013; 4:27. [PMID: 24098981 PMCID: PMC3856589 DOI: 10.1186/2041-9139-4-27] [Citation(s) in RCA: 117] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Accepted: 08/14/2013] [Indexed: 12/21/2022] Open
Abstract
The question of whether the ancestral bilaterian had a central nervous system (CNS) or a diffuse ectodermal nervous system has been hotly debated. Considerable evidence supports the theory that a CNS evolved just once. However, an alternative view proposes that the chordate CNS evolved from the ectodermal nerve net of a hemichordate-like ancestral deuterostome, implying independent evolution of the CNS in chordates and protostomes. To specify morphological divisions along the anterior/posterior axis, this ancestor used gene networks homologous to those patterning three organizing centers in the vertebrate brain: the anterior neural ridge, the zona limitans intrathalamica and the isthmic organizer, and subsequent evolution of the vertebrate brain involved elaboration of these ancestral signaling centers; however, all or part of these signaling centers were lost from the CNS of invertebrate chordates. The present review analyzes the evidence for and against these theories. The bulk of the evidence indicates that a CNS evolved just once - in the ancestral bilaterian. Importantly, in both protostomes and deuterostomes, the CNS represents a portion of a generally neurogenic ectoderm that is internalized and receives and integrates inputs from sensory cells in the remainder of the ectoderm. The expression patterns of genes involved in medio/lateral (dorso/ventral) patterning of the CNS are similar in protostomes and chordates; however, these genes are not similarly expressed in the ectoderm outside the CNS. Thus, their expression is a better criterion for CNS homologs than the expression of anterior/posterior patterning genes, many of which (for example, Hox genes) are similarly expressed both in the CNS and in the remainder of the ectoderm in many bilaterians. The evidence leaves hemichordates in an ambiguous position - either CNS centralization was lost to some extent at the base of the hemichordates, or even earlier, at the base of the hemichordates + echinoderms, or one of the two hemichordate nerve cords is homologous to the CNS of protostomes and chordates. In any event, the presence of part of the genetic machinery for the anterior neural ridge, the zona limitans intrathalamica and the isthmic organizer in invertebrate chordates together with similar morphology indicates that these organizers were present, at least in part, at the base of the chordates and were probably elaborated upon in the vertebrate lineage.
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Affiliation(s)
- Linda Z Holland
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California at San Diego, La Jolla, CA 92093-0202, USA
| | - João E Carvalho
- Laboratoire de Biologie du Développement de Villefranche-sur-Mer (UMR 7009 – CNRS/UPMC), Observatoire Océanologique de Villefranche-sur-Mer, 181 Chemin du Lazaret, B.P. 28, 06230 Villefranche-sur-Mer, France
| | - Hector Escriva
- CNRS, UMR 7232, BIOM, Université Pierre et Marie Curie Paris 06, Observatoire Océanologique, 66650 Banyuls-sur-Mer, France
| | - Vincent Laudet
- Institut de Génomique Fonctionnelle de Lyon (CNRS UMR5242, UCBL, ENS, INRA 1288), Ecole Normale Supérieure de Lyon, 46 allée d’Italie, 69364 Lyon Cedex 07, France
| | - Michael Schubert
- Laboratoire de Biologie du Développement de Villefranche-sur-Mer (UMR 7009 – CNRS/UPMC), Observatoire Océanologique de Villefranche-sur-Mer, 181 Chemin du Lazaret, B.P. 28, 06230 Villefranche-sur-Mer, France
| | - Sebastian M Shimeld
- Department of Zoology, University of Oxford, The Tinbergen Building, South Parks Road, Oxford OX1 3PS, UK
| | - Jr-Kai Yu
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 11529, Taiwan
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25
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Beckers P, Loesel R, Bartolomaeus T. The nervous systems of basally branching nemertea (palaeonemertea). PLoS One 2013; 8:e66137. [PMID: 23785478 PMCID: PMC3681988 DOI: 10.1371/journal.pone.0066137] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Accepted: 05/01/2013] [Indexed: 11/18/2022] Open
Abstract
In recent years, a lot of studies have been published dealing with the anatomy of the nervous system in different spiralian species. The only nemertean species investigated in this context probably shows derived characters and thus the conditions found there are not useful in inferring the relationship between nemerteans and other spiralian taxa. Ingroup relationships within Nemertea are still unclear, but there is some agreement that the palaeonemerteans form a basal, paraphyletic grade. Thus, palaeonemertean species are likely the most informative when comparing with other invertebrate groups. We therefore analyzed the nervous system of several palaeonemertean species by combining histology and immunostaining. 3D reconstructions based on the aligned slices were performed to get an overall impression of the central nervous system, and immunohistochemistry was chosen to reveal fine structures and to be able to compare the data with recently published results. The insights presented here permit a first attempt to reconstruct the primary organization of the nemertean nervous system. This comparative analysis allows substantiating homology hypotheses for nerves of the peripheral nervous system. This study also provides evidence that the nemertean brain primarily consists of two lobes connected by a strong ventral commissure and one to several dorsal commissures. During nemertean evolution, the brain underwent continuous compartmentalization into a pair of dorsal and ventral lobes interconnected by commissures and lateral tracts. Given that this conclusion can be corroborated by cladistic analyses, nemerteans should share a common ancestor with spiralians that primarily have a simple brain consisting of paired medullary, frontally commissurized and reinforced cords. Such an organization resembles the situation found in presumably basally branching annelids or mollusks.
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Affiliation(s)
- Patrick Beckers
- Institute for Evolutionary Biology and Ecology, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany.
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HELM CONRAD, SCHEMEL SINA, BLEIDORN CHRISTOPH. Temporal Plasticity in Annelid Development-Ontogeny ofPhyllodoce groenlandica(Phyllodocidae, Annelida) Reveals Heterochronous Patterns. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2013; 320:166-78. [DOI: 10.1002/jez.b.22492] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Revised: 01/18/2013] [Accepted: 01/22/2013] [Indexed: 11/09/2022]
Affiliation(s)
- CONRAD HELM
- Molecular Evolution & Systematics of Animals; Institute of Biology, University of Leipzig; Leipzig; Germany
| | - SINA SCHEMEL
- Molecular Evolution & Systematics of Animals; Institute of Biology, University of Leipzig; Leipzig; Germany
| | - CHRISTOPH BLEIDORN
- Molecular Evolution & Systematics of Animals; Institute of Biology, University of Leipzig; Leipzig; Germany
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Miyamoto N, Shinozaki A, Fujiwara Y. Neuroanatomy of the vestimentiferan tubeworm Lamellibrachia satsuma provides insights into the evolution of the polychaete nervous system. PLoS One 2013; 8:e55151. [PMID: 23372830 PMCID: PMC3553155 DOI: 10.1371/journal.pone.0055151] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Accepted: 12/20/2012] [Indexed: 11/18/2022] Open
Abstract
Vestimentiferan tubeworms are marine invertebrates that inhabit chemosynthetic environments, and although recent molecular phylogenetic analyses have suggested that vestimentiferan tubeworms are derived from polychaete annelids, they show some morphological features that are different from other polychaetes. For example, vestimentiferans lack a digestive tract and have less body segments and comparative neuroanatomy can provide essential insight into the vestimentiferan body plan and its evolution. In the present study, we investigated the adult nervous system in the vestimentiferan Lamellibrachia satsuma using antibodies against synapsin, serotonin, FMRMamide and acetylated α-tubulin. We also examined the expressions of neural marker genes, elav and synaptotagmin to reveal the distribution of neuronal cell bodies. Brain anatomy shows simple organization in Lamellibrachia compared to other polychaetes. This simplification is probably due to the loss of the digestive tract, passing through the body between the brain and the subesophageal ganglion. In contrast, the ventral nerve cord shows a repeated organizational structure as in the other polychaetes, despite the absence of the multiple segmentation of the trunk. These results suggest that the brain anatomy is variable depending on the function and the condition of surrounding tissues, and that the formation of the rope ladder-like nervous system of the ventral nerve cord is independent from segmentation in polychaetes.
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Affiliation(s)
- Norio Miyamoto
- Institute of Biogeosciences, Japan Agency for Marine-Earth Science and Technology, Yokosuka, Japan.
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Andrew DR, Brown SM, Strausfeld NJ. The minute brain of the copepod Tigriopus californicus supports a complex ancestral ground pattern of the tetraconate cerebral nervous systems. J Comp Neurol 2012; 520:3446-70. [DOI: 10.1002/cne.23099] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Heuer CM, Kollmann M, Binzer M, Schachtner J. Neuropeptides in insect mushroom bodies. ARTHROPOD STRUCTURE & DEVELOPMENT 2012; 41:199-226. [PMID: 22401884 DOI: 10.1016/j.asd.2012.02.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Revised: 02/22/2012] [Accepted: 02/23/2012] [Indexed: 05/31/2023]
Abstract
Owing to their experimental amenability, insect nervous systems continue to be in the foreground of investigations into information processing in - ostensibly - simple neuronal networks. Among the cerebral neuropil regions that hold a particular fascination for neurobiologists are the paired mushroom bodies, which, despite their function in other behavioral contexts, are most renowned for their role in learning and memory. The quest to understand the processes that underlie these capacities has been furthered by research focusing on unraveling neuroanatomical connections of the mushroom bodies and identifying key players that characterize the molecular machinery of mushroom body neurons. However, on a cellular level, communication between intrinsic and extrinsic mushroom body neurons still remains elusive. The present account aims to provide an overview on the repertoire of neuropeptides expressed in and utilized by mushroom body neurons. Existing data for a number of insect representatives is compiled and some open gaps in the record are filled by presenting additional original data.
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Affiliation(s)
- Carsten M Heuer
- Philipps-University Marburg, Department of Biology, Animal Physiology, Marburg, Germany.
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Comparative neuroanatomy of Caudofoveata, Solenogastres, Polyplacophora, and Scaphopoda (Mollusca) and its phylogenetic implications. ZOOMORPHOLOGY 2012. [DOI: 10.1007/s00435-012-0150-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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31
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CAPA MARÍA, HUTCHINGS PAT, PEART RACHAEL. Systematic revision of Sabellariidae (Polychaeta) and their relationships with other polychaetes using morphological and DNA sequence data. Zool J Linn Soc 2012. [DOI: 10.1111/j.1096-3642.2011.00767.x] [Citation(s) in RCA: 20] [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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Pflüger HJ, Field LH, Nishino H, Currie MJ. Neuromodulatory unpaired median neurons in the New Zealand tree weta, Hemideina femorata. JOURNAL OF INSECT PHYSIOLOGY 2011; 57:1420-1430. [PMID: 21810425 DOI: 10.1016/j.jinsphys.2011.07.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Revised: 07/08/2011] [Accepted: 07/13/2011] [Indexed: 05/31/2023]
Abstract
Wetas are ancient Gondwanan orthopterans (Anostostomatidae) with many species endemic to New Zealand. Like all Orthoptera they possess efferent neuromodulatory dorsal unpaired median (DUM) neurons, with bilaterally symmetrical axons, that are important components of motor networks. These neurons produce overshooting action potentials and are easily stimulated by a variety of external mechanosensory stimuli delivered to the body and appendages. In particular, stimulation of the antennae, mouth parts, tarsi and femora of the legs, abdomen, cerci and ovipositor is very effective in activating DUM neurons in the metathoracic ganglion of wetas. In addition, looming visual stimuli or light on-, light off-stimuli excite many metathoracic DUM neurons. These DUM sensory reflex pathways remain viable after the prothoracic to subesophageal connective is cut, whereas in locusts such reflex pathways are interrupted by the ablation. This suggests that, in wetas, sensory reflex pathways for DUM activation are organized in a less centralized fashion than in locusts, and may therefore reflect a plesiomorphic evolutionary state in the weta. In addition, many weta DUM neurons exhibit slow rhythmic bursting which also persists following the connective ablation.
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Affiliation(s)
- Hans-Joachim Pflüger
- University of Canterbury, School of Biological Sciences, Christchurch, New Zealand.
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Beckers P, Faller S, Loesel R. Lophotrochozoan neuroanatomy: An analysis of the brain and nervous system of Lineus viridis(Nemertea) using different staining techniques. Front Zool 2011; 8:17. [PMID: 21771310 PMCID: PMC3160363 DOI: 10.1186/1742-9994-8-17] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Accepted: 07/19/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The now thriving field of neurophylogeny that links the morphology of the nervous system to early evolutionary events relies heavily on detailed descriptions of the neuronal architecture of taxa under scrutiny. While recent accounts on the nervous system of a number of animal clades such as arthropods, annelids, and molluscs are abundant, in depth studies of the neuroanatomy of nemerteans are still wanting. In this study, we used different staining techniques and confocal laser scanning microscopy to reveal the architecture of the nervous system of Lineus viridis with high anatomical resolution. RESULTS In L. viridis, the peripheral nervous system comprises four distinct but interconnected nerve plexus. The central nervous system consists of a pair of medullary cords and a brain. The brain surrounds the proboscis and is subdivided into four voluminous lobes and a ring of commissural tracts. The brain is well developed and contains thousands of neurons. It does not reveal compartmentalized neuropils found in other animal groups with elaborate cerebral ganglia. CONCLUSIONS The detailed analysis of the nemertean nervous system presented in this study does not support any hypothesis on the phylogenetic position of Nemertea within Lophotrochozoa. Neuroanatomical characters that are described here are either common in other lophotrochozoan taxa or are seemingly restricted to nemerteans. Since detailed descriptions of the nervous system of adults in other nemertean species have not been available so far, this study may serve as a basis for future studies that might add data to the unsettled question of the nemertean ground pattern and the position of this taxon within the phylogenetic tree.
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Affiliation(s)
- Patrick Beckers
- Institute of Evolutionary Biology and Ecology, University of Bonn, 53121 Bonn, Germany
| | - Simone Faller
- Unit of Developmental Biology and Morphology of Animals, Institute for Biology II, RWTH Aachen University, 52070 Aachen, Germany
| | - Rudi Loesel
- Unit of Developmental Biology and Morphology of Animals, Institute for Biology II, RWTH Aachen University, 52070 Aachen, Germany
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Farris SM. Are mushroom bodies cerebellum-like structures? ARTHROPOD STRUCTURE & DEVELOPMENT 2011; 40:368-79. [PMID: 21371566 DOI: 10.1016/j.asd.2011.02.004] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2010] [Revised: 02/08/2011] [Accepted: 02/19/2011] [Indexed: 05/20/2023]
Abstract
The mushroom bodies are distinctive neuropils in the protocerebral brain segments of many protostomes. A defining feature of mushroom bodies is their intrinsic neurons, masses of cytoplasm-poor globuli cells that form a system of lobes with their densely-packed, parallel-projecting axon-like processes. In insects, the role of the mushroom bodies in olfactory processing and associative learning and memory has been studied in depth, but several lines of evidence suggest that the function of these higher brain centers cannot be restricted to these roles. The present account considers whether insight into an underlying function of mushroom bodies may be provided by cerebellum-like structures in vertebrates, which are similarly defined by the presence of masses of tiny granule cells that emit thin parallel fibers forming a dense molecular layer. In vertebrates, the shared neuroarchitecture of cerebellum-like structures has been suggested to underlie a common functional role as adaptive filters for the removal of predictable sensory elements, such as those arising from reafference, from the total sensory input. Cerebellum-like structures include the vertebrate cerebellum, the electrosensory lateral line lobe, dorsal and medial octavolateral nuclei of fish, and the dorsal cochlear nucleus of mammals. The many architectural and physiological features that the insect mushroom bodies share with cerebellum-like structures suggest that it might be fruitful to consider mushroom body function in light of a possible role as adaptive sensory filters. The present account thus presents a detailed comparison of the insect mushroom bodies with vertebrate cerebellum-like structures.
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Affiliation(s)
- Sarah M Farris
- Department of Biology, West Virginia University, 3139 Life Sciences Building, 53 Campus Drive, Morgantown, WV 26505, USA.
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Stegner MEJ, Richter S. Morphology of the brain in Hutchinsoniella macracantha (Cephalocarida, Crustacea). ARTHROPOD STRUCTURE & DEVELOPMENT 2011; 40:221-243. [PMID: 21679884 DOI: 10.1016/j.asd.2011.04.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2010] [Revised: 04/18/2011] [Accepted: 04/18/2011] [Indexed: 05/30/2023]
Abstract
External morphological features of Cephalocarida have long been interpreted as plesiomorphic with regard to those of other crustaceans. Based on transmission electron microscopy and light microscopy, however, the brain in the cephalocarid Hutchinsoniella macracantha has been shown to contain a number of structures that are more difficult to interpret in an evolutionary context. These include the multi-lobed complex, a unique cluster of neuropils associated with the olfactory lobes. To establish a well-founded comparison of phylogenetically relevant, neuroanatomical data from Cephalocarida to other arthropods, we investigated the brain in H. macracantha using immunolabeling (acetylated α-tubulin, serotonin, RFamide, histamine) and nuclear counter stains of whole mounts and vibratome sections analyzing specimens with confocal laser scanning microscopy and computer-aided 3D-reconstruction. Other 3D-reconstructions were based on serial 1 μm semi-thin sections. The multi-lobed complex features a pedunculus and shows detailed homologies with the mushroom bodies of certain Insecta and Lithobiomorpha (Chilopoda), suggesting that the hemiellipsoid bodies in Remipedia and Malacostraca have derived from a cephalocarid-like pattern. Like the corresponding tracts in Insecta, the olfactory globular tracts linking the multi-lobed complex to the olfactory lobes are ipsilateral, probably constituting the plesiomorphic pattern from which the decussating tracts in Remipedia and Malacostraca have evolved. The olfactory lobes in H. macracantha are uniquely organized into vertical stacks of olfactory glomeruli whose exact shape could not be identified. Similarly to Malacostraca and Insecta, the olfactory glomeruli in H. macracantha are innervated by serotonin-like, RFamide-like, and histamine-like immunoreactive interneurons. This suggests homology of the olfactory lobes across Tetraconata, despite the different morphological organization. Although H. macracantha lacks elongated, unpaired midline neuropils known from the protocerebrum of other Arthropoda, the possible rudiment of a central-body-like neuropil that receives decussating fibers from anterior somata was revealed by the serotonin-like immunoreactive pattern.
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Affiliation(s)
- Martin E J Stegner
- Institut für Biowissenschaften, Abteilung Allgemeine und Spezielle Zoologie, Universität Rostock, Universitätsplatz 2, 18055 Rostock, Germany.
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Strausfeld NJ, Andrew DR. A new view of insect-crustacean relationships I. Inferences from neural cladistics and comparative neuroanatomy. ARTHROPOD STRUCTURE & DEVELOPMENT 2011; 40:276-88. [PMID: 21333750 DOI: 10.1016/j.asd.2011.02.002] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Revised: 01/28/2011] [Accepted: 02/08/2011] [Indexed: 05/15/2023]
Abstract
Traditional hypotheses regarding the relationships of the major arthropod lineages focus on suites of comparable characters, often those that address features of the exoskeleton. However, because of the enormous morphological variety among arthropods, external characters may lead to ambiguities of interpretation and definition, particularly when species have undergone evolutionary simplification and reversal. Here we present the results of a cladistic analysis using morphological characters associated with brains and central nervous systems, based on the evidence that cerebral organization is generally robust over geological time. Well-resolved, strongly supported phylogenies were obtained from a neuromorphological character set representing a variety of discrete neuroanatomical traits. Phylogenetic hypotheses from this analysis support many accepted relationships, including monophyletic Chelicerata, Myriapoda, and Hexapoda, paraphyletic Crustacea and the union of Hexapoda and Crustacea (Tetraconata). They also support Mandibulata (Myriapoda + Tetraconata). One problematic result, which can be explained by symplesiomorphies that are likely to have evolved in deep time, is the inability to resolve Onychophora as a taxon distinct from Arthropoda. Crucially, neuronal cladistics supports the heterodox conclusion that both Hexapoda and Malacostraca are derived from a common ancestor that possessed a suite of discrete neural centers comprising an elaborate brain. Remipedes and copepods, both resolved as basal to Branchiopoda share a neural ground pattern with Malacostraca. These findings distinguish Hexapoda (Insecta) from Branchiopoda, which is the sister group of the clade Malacostraca + Hexapoda. The present study resolves branchiopod crustaceans as descendents of an ancestor with a complex brain, which means that they have evolved secondary simplification and the loss or reduction of numerous neural systems.
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Affiliation(s)
- Nicholas J Strausfeld
- Department of Neuroscience, University of Arizona, 1040 E. 4th St., Gould-Simpson Bldg. #611, Tucson, AZ 85721, USA.
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Winchell CJ, Valencia JE, Jacobs DK. Expression of Distal-less, dachshund, and optomotor blind in Neanthes arenaceodentata (Annelida, Nereididae) does not support homology of appendage-forming mechanisms across the Bilateria. Dev Genes Evol 2010; 220:275-95. [PMID: 21116826 PMCID: PMC3005117 DOI: 10.1007/s00427-010-0346-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2010] [Accepted: 11/09/2010] [Indexed: 01/11/2023]
Abstract
The similarity in the genetic regulation of arthropod and vertebrate appendage formation has been interpreted as the product of a plesiomorphic gene network that was primitively involved in bilaterian appendage development and co-opted to build appendages (in modern phyla) that are not historically related as structures. Data from lophotrochozoans are needed to clarify the pervasiveness of plesiomorphic appendage-forming mechanisms. We assayed the expression of three arthropod and vertebrate limb gene orthologs, Distal-less (Dll), dachshund (dac), and optomotor blind (omb), in direct-developing juveniles of the polychaete Neanthes arenaceodentata. Parapodial Dll expression marks pre-morphogenetic notopodia and neuropodia, becoming restricted to the bases of notopodial cirri and to ventral portions of neuropodia. In outgrowing cephalic appendages, Dll activity is primarily restricted to proximal domains. Dll expression is also prominent in the brain. dac expression occurs in the brain, nerve cord ganglia, a pair of pharyngeal ganglia, presumed interneurons linking a pair of segmental nerves, and in newly differentiating mesoderm. Domains of omb expression include the brain, nerve cord ganglia, one pair of anterior cirri, presumed precursors of dorsal musculature, and the same pharyngeal ganglia and presumed interneurons that express dac. Contrary to their roles in outgrowing arthropod and vertebrate appendages, Dll, dac, and omb lack comparable expression in Neanthes appendages, implying independent evolution of annelid appendage development. We infer that parapodia and arthropodia are not structurally or mechanistically homologous (but their primordia might be), that Dll's ancestral bilaterian function was in sensory and central nervous system differentiation, and that locomotory appendages possibly evolved from sensory outgrowths.
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Affiliation(s)
- Christopher J. Winchell
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, 621 Charles E. Young Drive South, Los Angeles, CA 90095-1606 USA
| | - Jonathan E. Valencia
- Division of Biology, California Institute of Technology, 1200 East California Boulevard; MC 156-29, Pasadena, CA 91125 USA
| | - David K. Jacobs
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, 621 Charles E. Young Drive South, Los Angeles, CA 90095-1606 USA
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Richter S, Loesel R, Purschke G, Schmidt-Rhaesa A, Scholtz G, Stach T, Vogt L, Wanninger A, Brenneis G, Döring C, Faller S, Fritsch M, Grobe P, Heuer CM, Kaul S, Møller OS, Müller CHG, Rieger V, Rothe BH, Stegner MEJ, Harzsch S. Invertebrate neurophylogeny: suggested terms and definitions for a neuroanatomical glossary. Front Zool 2010; 7:29. [PMID: 21062451 PMCID: PMC2996375 DOI: 10.1186/1742-9994-7-29] [Citation(s) in RCA: 232] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2010] [Accepted: 11/09/2010] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Invertebrate nervous systems are highly disparate between different taxa. This is reflected in the terminology used to describe them, which is very rich and often confusing. Even very general terms such as 'brain', 'nerve', and 'eye' have been used in various ways in the different animal groups, but no consensus on the exact meaning exists. This impedes our understanding of the architecture of the invertebrate nervous system in general and of evolutionary transformations of nervous system characters between different taxa. RESULTS We provide a glossary of invertebrate neuroanatomical terms with a precise and consistent terminology, taxon-independent and free of homology assumptions. This terminology is intended to form a basis for new morphological descriptions. A total of 47 terms are defined. Each entry consists of a definition, discouraged terms, and a background/comment section. CONCLUSIONS The use of our revised neuroanatomical terminology in any new descriptions of the anatomy of invertebrate nervous systems will improve the comparability of this organ system and its substructures between the various taxa, and finally even lead to better and more robust homology hypotheses.
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Affiliation(s)
- Stefan Richter
- Universität Rostock, Institut für Biowissenschaften, Abteilung für Allgemeine und Spezielle Zoologie, Universitätsplatz 2, D-18055 Rostock, Germany
| | - Rudi Loesel
- RWTH Aachen, Institute of Biology II, Department of Developmental Biology and Morphology of Animals, Mies-van-der-Rohe-Straße 15, D-52056 Aachen, Germany
| | - Günter Purschke
- Universität Osnabrück, Fachbereich Biologie/Chemie, AG Zoologie, Barbarastraße 11,, D-49069 Osnabrück, Germany
| | - Andreas Schmidt-Rhaesa
- Biozentrum Grindel/Zoological Museum, Martin-Luther-King-Platz 3, D-20146 Hamburg, Germany
| | - Gerhard Scholtz
- Humboldt-Universität zu Berlin, Institut für Biologie - Vergleichende Zoologie, Philippstraße 13, D-10115 Berlin, Germany
| | - Thomas Stach
- Freie Universität Berlin, Zoologie - Systematik und Evolutionsforschung, Königin-Luise-Straße 1-3, D-14195 Berlin, Germany
| | - Lars Vogt
- Universität Bonn, Institut für Evolutionsbiologie und Ökologie, An der Immenburg 1, D-53121 Bonn, Germany
| | - Andreas Wanninger
- University of Copenhagen, Department of Biology, Research Group for Comparative Zoology, Universitetsparken 15, DK-2100 Copenhagen, Denmark
| | - Georg Brenneis
- Universität Rostock, Institut für Biowissenschaften, Abteilung für Allgemeine und Spezielle Zoologie, Universitätsplatz 2, D-18055 Rostock, Germany
- Humboldt-Universität zu Berlin, Institut für Biologie - Vergleichende Zoologie, Philippstraße 13, D-10115 Berlin, Germany
| | - Carmen Döring
- Universität Osnabrück, Fachbereich Biologie/Chemie, AG Zoologie, Barbarastraße 11,, D-49069 Osnabrück, Germany
| | - Simone Faller
- RWTH Aachen, Institute of Biology II, Department of Developmental Biology and Morphology of Animals, Mies-van-der-Rohe-Straße 15, D-52056 Aachen, Germany
| | - Martin Fritsch
- Universität Rostock, Institut für Biowissenschaften, Abteilung für Allgemeine und Spezielle Zoologie, Universitätsplatz 2, D-18055 Rostock, Germany
| | - Peter Grobe
- Universität Bonn, Institut für Evolutionsbiologie und Ökologie, An der Immenburg 1, D-53121 Bonn, Germany
| | - Carsten M Heuer
- RWTH Aachen, Institute of Biology II, Department of Developmental Biology and Morphology of Animals, Mies-van-der-Rohe-Straße 15, D-52056 Aachen, Germany
| | - Sabrina Kaul
- Freie Universität Berlin, Zoologie - Systematik und Evolutionsforschung, Königin-Luise-Straße 1-3, D-14195 Berlin, Germany
| | - Ole S Møller
- Universität Rostock, Institut für Biowissenschaften, Abteilung für Allgemeine und Spezielle Zoologie, Universitätsplatz 2, D-18055 Rostock, Germany
| | - Carsten HG Müller
- Ernst-Moritz-Arndt-Universität Greifswald, Zoologisches Institut, Cytologie und Evolutionsbiologie, Johann-Sebastian-Bach-Straße 11/12, D-17487 Greifswald, Germany
| | - Verena Rieger
- Ernst-Moritz-Arndt-Universität Greifswald, Zoologisches Institut, Cytologie und Evolutionsbiologie, Johann-Sebastian-Bach-Straße 11/12, D-17487 Greifswald, Germany
| | - Birgen H Rothe
- Biozentrum Grindel/Zoological Museum, Martin-Luther-King-Platz 3, D-20146 Hamburg, Germany
| | - Martin EJ Stegner
- Universität Rostock, Institut für Biowissenschaften, Abteilung für Allgemeine und Spezielle Zoologie, Universitätsplatz 2, D-18055 Rostock, Germany
| | - Steffen Harzsch
- Ernst-Moritz-Arndt-Universität Greifswald, Zoologisches Institut, Cytologie und Evolutionsbiologie, Johann-Sebastian-Bach-Straße 11/12, D-17487 Greifswald, Germany
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