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Ian Orchard - One of the best experts on this subject based on the ideXlab platform.
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immunohistochemical localization of tyrosine hydroxylase in the ventral Nerve Cord of the stick insect carausius morosus including neurons innervating the salivary glands
Cell and Tissue Research, 1996Co-Authors: Ian OrchardAbstract:The distribution of tyrosine hydroxylase-like immunoreactive neurons is mapped in the ventral Nerve Cord of the stick insect, Carausius morosus. This study also examines the tyrosine hydroxylase- and serotonin-like immunoreactive elements in the salivary glands of Carausius morosus. Tyrosine hydroxylase is the first and rate-limiting enzyme in the pathway for the production of catecholamines; therefore, tyrosine hydroxylase-like immunoreactive neurons are likely to contain catecholamines. Approximately 225 tyrosine hydroxylase-like immunoreactive neurons are present in the ventral Nerve Cord. The majority of these neurons appear to be interneurons. The suboesophageal ganglion contains the only unpaired neuron and the only pair of peripherally projecting tyrosine hydroxylase-like immunoreactive neurons in the ventral Nerve Cord. The peripherally projecting neurons project to the salivary glands via the salivary Nerve. Each neuron in this pair is termed the salivary neuron 1. The remaining tyrosine hydroxylase-like immunoreactive neurons in the ventral Nerve Cord are interneurons and exhibit a characteristic distribution within the thoracic and the abdominal ganglia. Serotoninlike immunoreactivity is also present in the salivary glands. Positive staining of the suboesophageal ganglion for serotoninlike immunoreactivity indicates the presence of several neuron pairs including a large pair along the ventral posterior midline that project to the salivary glands via the salivary Nerve. Each neuron in this pair is termed the salivary neuron 2. Backfilling of the salivary Nerve with cobalt chloride reveals the presence of only two neurons within the suboesophageal ganglion that project to the salivary glands; these neurons are the salivary neurons 1 and 2. Reverse-phase high-performance liquid chromatography coupled with electrochemical detection of ventral Nerve Cord and salivary gland homogenates confirms the presence of dopamine and serotonin.
Steffen Harzsch - One of the best experts on this subject based on the ideXlab platform.
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serotonin immunoreactive neurons in the ventral Nerve Cord of remipedia crustacea support for a sister group relationship of remipedia and hexapoda
BMC Evolutionary Biology, 2013Co-Authors: Torben Stemme, Steffen Harzsch, Thomas M Iliffe, Stefan Koenemann, Bjorn M Von Reumont, Gerd BickerAbstract:Remipedia were initially seen as a primitive taxon within Pancrustacea based on characters considered ancestral, such as the homonomously segmented trunk. Meanwhile, several morphological and molecular studies proposed a more derived position of Remipedia within Pancrustacea, including a sister group relationship to Hexapoda. Because of these conflicting hypotheses, fresh data are crucial to contribute new insights into euarthropod phylogeny. The architecture of individually identifiable serotonin-immunoreactive neurons has successfully been used for phylogenetic considerations in Euarthropoda. Here, we identified neurons in three species of Remipedia with an antiserum against serotonin and compared our findings to reconstructed ground patterns in other euarthropod taxa. Additionally, we traced neurite connectivity and neuropil outlines using antisera against acetylated α-tubulin and synapsin. The ventral Nerve Cord of Remipedia displays a typical rope-ladder-like arrangement of separate metameric ganglia linked by paired longitudinally projecting connectives. The peripheral projections comprise an intersegmental Nerve, consisting of two branches that fuse shortly after exiting the connectives, and the segmental anterior and posterior Nerve. The distribution and morphology of serotonin-immunoreactive interneurons in the trunk segments is highly conserved within the remipede species we analyzed, which allows for the reconstruction of a ground pattern: two posterior and one anterior pair of serotonin-immunoreactive neurons that possess a single contralateral projection. Additionally, three pairs of immunoreactive neurons are found in the medial part of each hemiganglion. In one species (Cryptocorynetes haptodiscus), the anterior pair of immunoreactive neurons is missing. The anatomy of the remipede ventral Nerve Cord with its separate metameric ganglia mirrors the external morphology of the animal’s trunk. The rope-ladder-like structure and principal architecture of the segmental ganglia in Remipedia corresponds closely to that of other Euarthropoda. A comparison of the serotonin-immunoreactive cell arrangement of Remipedia to reconstructed ground patterns of major euarthropod taxa supports a homology of the anterior and posterior neurons in Pancrustacea. These neurons in Remipedia possess unbranched projections across the midline, pointing towards similarities to the hexapod pattern. Our findings are in line with a growing number of phylogenetic investigations proposing Remipedia to be a rather derived crustacean lineage that perhaps has close affinities to Hexapoda.
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Engrailed-like immunoreactivity in the embryonic ventral Nerve Cord of the Marbled Crayfish (Marmorkrebs)
Invertebrate Neuroscience, 2008Co-Authors: Kathia Fabritius-vilpoux, Sonja Bisch-knaden, Steffen HarzschAbstract:The homeobox transcription factor Engrailed is involved in controlling segmentation during arthropod germ band formation but also in establishing individual neuronal identities during later embryogenesis. In Crustacea, most studies analysing the expression of Engrailed so far have focussed on its function as segment polarity gene. In continuation to these previous studies, we analysed the neuronal expression of the Engrailed protein by immunohistochemistry in the embryonic Nerve Cord of a parthenogenetic crustacean, the Marbled Crayfish (Marmorkrebs). We paid particular attention to the individual identification of Engrailed expressing putative neuroblasts in the crayfish embryos. Engrailed positive cells in the neuroectoderm were counted, measured and mapped from 38 to 65% of embryonic development. That way, several Engrailed positive putative neuroblasts and putative neurons were identified. Our findings are compared with earlier studies on Engrailed expression during germ band formation in Crustacea. Recent data on neurogenesis in an amphipod crustacean have provided compelling evidence for the homology of several identified neuroblasts between this amphipod and insects. The present report may serve as a basis to explore the question if during crustacean neurogenesis additional communalities with insects exist.
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embryonic development of the histaminergic system in the ventral Nerve Cord of the marbled crayfish marmorkrebs
Tissue & Cell, 2008Co-Authors: Verena Rieger, Steffen HarzschAbstract:The embryonic development of neurotransmitter systems in crustaceans so far is poorly understood. Therefore, in the current study we monitored the ontogeny of histamine-immunoreactive neurons in the ventral Nerve Cord of the Marbled Crayfish, an emerging crustacean model system for developmental studies. The first histaminergic neurons arise around 60% of embryonic development, well after the primordial axonal scaffold of the ventral Nerve Cord has been established. This suggests that histaminergic neurons do not serve as pioneer neurons but that their axons follow well established axonal tracts. The developmental sequence of the different types of histaminergic neurons is charted in this study. The analysis of the histaminergic structures is also extended into adult specimens, showing a persistence of embryonic histaminergic neurons into adulthood. Our data are compared to the pattern of histaminergic neurons in other crustaceans and discussed with regard to our knowledge on other aspects of neurogenesis in Crustacea. Furthermore, the possible role of histaminergic neurons as characters in evolutionary considerations is evaluated.
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ontogeny of the ventral Nerve Cord in malacostracan crustaceans a common plan for neuronal development in crustacea hexapoda and other arthropoda
Arthropod Structure & Development, 2003Co-Authors: Steffen HarzschAbstract:Abstract This review sets out to summarize our current knowledge on the structural layout of the embryonic ventral Nerve Cord in decapod crustaceans and its development from stem cell to the mature structure. In Decapoda, neuronal stem cells, the neuroblasts, mostly originate from ectodermal stem cells, the ectoteloblast, via a defined lineage. The neuroblasts undergo repeated asymmetric division and generate ganglion mother cells. The ganglion mother cells later divide again to give birth to ganglion cells (neurons) and there is increasing evidence now that ganglion mother cells divide again not only once but repeatedly. Various other aspects of neuroblast proliferation such as their temporal patterns of mitotic activity and spatial arrangement as well as the relation of neurogenesis to the development of the segmental appendages and maturation of motor behaviors are described. The link between cell lineage and cell differentiation in Decapoda so far has only been established for the midline neuroblast. However, there are several other identified early differentiating neurons, the outgrowing neurites of which pioneer the axonal scaffold within the neuromeres of the ventral Nerve Cord. The maturation of identified neurons as examined by immunohistochemistry against their neurotransmitters or engrailed, is briefly described. These processes are compared to other Arthropoda (icluding Onychophora, Chelicerata, Diplopoda and Hexapoda) in order to shed light on variations and conserved motifs of the theme ‘neurogenesis’. The question of a ‘common plan for neuronal development’ in the ventral Nerve Cords of Hexapoda and Crustacea is critically evaluated and the possibility of homologous neurons arising through divergent developmental pathways is discussed.
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evolution of identified arthropod neurons the serotonergic system in relation to engrailed expressing cells in the embryonic ventral Nerve Cord of the american lobster homarus americanus milne edwards 1873 malacostraca pleocyemata homarida
Developmental Biology, 2003Co-Authors: Steffen HarzschAbstract:One of the long-standing questions in zoology is that on the phylogenetic relationships within the Arthropoda. Comparative studies on structure and development of the nervous system can contribute important arguments to this discussion. In the present report, the arrangement of serotonin- and engrailed-expressing cells was examined in the embryonic ventral Nerve Cord of the American lobster Homarus americanus Milne Edwards, 1873 (Malacostraca, Pleocyemata, Homarida), and the spatial relationship of these two cell classes was explored by a double-labelling approach. The goal of this study was to determine whether the lobster serotonergic neurons are homologous to similar cells present in representatives of the Hexapoda and other Arthropoda. The results indicate that, in fact, these neurons in the lobster ventral Nerve Cord have corresponding counterparts in many other mandibulate taxa. Based on the finding of these homologies, the arrangement of serotonergic neurons in a model trunk ganglion of the mandibulate ground pattern was reconstructed as comprising an anterior and a posterior pair of serotonergic neurons per hemiganglion, each cell with both an ipsilateral and a contralateral neurite. Starting from this ground pattern, the evolutionary diversification of this class of neurons within the Mandibulata is discussed.
Angela B Lange - One of the best experts on this subject based on the ideXlab platform.
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isolation sequence and bioactivity of fmrfamide related peptides from the locust ventral Nerve Cord
Peptides, 1994Co-Authors: Angela B Lange, Neda M PeeffAbstract:Abstract The ventral Nerve Cord of the locust, Locusta migratoria , was examined for the presence of FMRFamide-related peptides (FaRPs). RP-HPLC coupled to an RIA specific for extended-RFamides revealed the presence of several FaRPs eluting at different percentages of acetonitrile. The sequences of five of these peptides were determined. Two sequences are identical to the two peptides previously sequenced from brain and retrocerebral complex of Locusta . These two peptides (PDVDHVFLRFamide and ADVGHVFLRFamide) were inhibitory when tested on locust oviduct contractions. The other peptides are novel with sequences of GQERNFLRFamide, AXXRNFIRFamide, and AFIRFamide. The synthesized peptides were stimulatory when tested on locust oviduct contractions, increasing the frequency and amplitude of spontaneous contractions and resulting in a basal contraction.
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tyrosine hydroxylase like immunoreactivity in the ventral Nerve Cord of the locust locusta migratoria including neurones innervating the salivary glands
Journal of Insect Physiology, 1992Co-Authors: Angela B Lange, Brenda B BrownAbstract:Abstract The distribution of tyrosine hydroxylase-like immunoreactivity was mapped in whole-mount preparations of the ventral Nerve Cord of adult male Locusta migratoria. Immunoreactivity was found in approx. 60 neuronal cell bodies and their processes distributed as bilaterally-symmetrical neurones throughout the various ganglia. Since tyrosine hydroxylase is the rate-limiting enzyme in catecholamine synthesis in vertebrates, it is likely that the neurones positive for tyrosine hydroxylase-like immunoreactivity in locust are catecholaminergic. The wide distribution of immunoreactivity indicates diverse functions for catecholamines in the locust. One function appears to be in the control of the salivary glands since an identifiable pair of neurones, the salivary neurones, SN1, are positive for tyrosine hydroxylase-like immunoreactivity. The remaining neurones appear to be interneurones with processes gaining in number and complexity in an anterior to posterior axis along the Nerve Cord. The mapping of these neurones is an initial step in the analysis of identifiable catecholamine-containing neurones in the locust.
Brenda B Brown - One of the best experts on this subject based on the ideXlab platform.
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tyrosine hydroxylase like immunoreactivity in the ventral Nerve Cord of the locust locusta migratoria including neurones innervating the salivary glands
Journal of Insect Physiology, 1992Co-Authors: Angela B Lange, Brenda B BrownAbstract:Abstract The distribution of tyrosine hydroxylase-like immunoreactivity was mapped in whole-mount preparations of the ventral Nerve Cord of adult male Locusta migratoria. Immunoreactivity was found in approx. 60 neuronal cell bodies and their processes distributed as bilaterally-symmetrical neurones throughout the various ganglia. Since tyrosine hydroxylase is the rate-limiting enzyme in catecholamine synthesis in vertebrates, it is likely that the neurones positive for tyrosine hydroxylase-like immunoreactivity in locust are catecholaminergic. The wide distribution of immunoreactivity indicates diverse functions for catecholamines in the locust. One function appears to be in the control of the salivary glands since an identifiable pair of neurones, the salivary neurones, SN1, are positive for tyrosine hydroxylase-like immunoreactivity. The remaining neurones appear to be interneurones with processes gaining in number and complexity in an anterior to posterior axis along the Nerve Cord. The mapping of these neurones is an initial step in the analysis of identifiable catecholamine-containing neurones in the locust.
G. Tsechpenakis - One of the best experts on this subject based on the ideXlab platform.
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part based motor neuron recognition in the drosophila ventral Nerve Cord
NeuroImage, 2014Co-Authors: X. Chang, A. Chiba, M D Kim, Rachel Stephens, G. TsechpenakisAbstract:We exploit the morphological stereotypy and relative simplicity of the Drosophila nervous system to model the diverse neuronal morphologies of individual motor neurons and understand underlying principles of synaptic connectivity in a motor circuit. In our analysis, we use images depicting single neurons labeled with green fluorescent protein (GFP) and serially imaged with laser scanning confocal microscopy. We model morphology with a novel formulation of Conditional Random Fields, a hierarchical latent-state CRF, to capture the highly varying compartment-based structure of the neurons (soma-axon-dendrites). In the training phase, we follow two approaches: (i) hierarchical learning, where compartment labels are given, and (ii) latent-state learning, where compartment labels are not given in the samples. We demonstrate the accuracy of our approach using wild-type motor neurons in the larval ventral Nerve Cord. However, our method can also be used for the identification of motor neuron mutations, as well as the automated annotation of the motor circuitry in wild type and mutant animals. Our method is directly applicable to the recognition of compartment-defined structures.
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Motor neuron recognition in the Drosophila ventral Nerve Cord
2013 IEEE 10th International Symposium on Biomedical Imaging, 2013Co-Authors: X. Chang, A. Chiba, G. TsechpenakisAbstract:We exploit the morphological stereotypy and relative simplicity of the Drosophila nervous system to model the diverse neuronal morphologies of individual motor neurons and understand underlying principles of synaptic connectivity in a motor circuit. In our analysis, we use images depicting single neurons labeled with green fluorescent protein (GFP) and serially imaged with laser scanning confocal microscopy. We model morphology with a novel formulation of Conditional Random Fields, a hierarchical latent-state CRF, to capture the highly varying compartment-based structure of the neurons (soma-axon-dendrites). In the training phase, we follow two approaches: (i) hierarchical learning, were compartment labels are given, and (ii) latent-state learning, where compartment labels are not given in the training samples. We demonstrate the accuracy of our approach using wild-type MNs in the larval ventral Nerve Cord. However, our method can also be used for the identification of MN mutations, as well as the automated annotation of the motor circuitry in wild type and mutant animals.
