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Marcelo J Villar - One of the best experts on this subject based on the ideXlab platform.
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distribution and characterization of corazonin in the central nervous system of triatoma infestans insecta heteroptera
Peptides, 2011Co-Authors: Beatriz P Settembrini, Daniela De Pasquale, Melissa Postal, Paulo Marcos Pinto, Celia R Carlini, Marcelo J VillarAbstract:The distribution of corazonin in the central nervous system of the heteropteran insect Triatoma infestans was studied by immunohistochemistry. The presence of corazonin isoforms was investigated using MALDI-TOF mass spectrometry in samples containing the brain, the subesophageal ganglion, the corpora cardiaca-corpus allatum complex and the anterior part of the aorta. Several groups of immunopositive perikarya were detected in the brain, the subesophageal ganglion and the thoracic ganglia. Regarding the brain, three clusters were observed in the protocerebrum. One of these clusters was formed by somata located near the entrance of the ocellar nerves whose fibers supplied the aorta and the corpora cardiaca. The remaining groups of the protocerebrum were located in the lateral soma cortex and at the boundary of the protocerebrum with the optic lobe. The optic lobe housed immunoreactive somata in the medial soma layer of the lobula and at the level of the first optic chiasma. The neuropils of the deutocerebrum and the tritocerebrum were immunostained, but no immunoreactive perikarya were detected. In the subesophageal ganglion, immunostained somata were found in the soma layers of the mandibular and labial Neuromeres, whereas in the mesothoracic ganglionic mass, they were observed in the mesothoracic, metathoracic and abdominal Neuromeres. Immunostained neurites were also found in the esophageal wall. The distribution pattern of corazonin like immunoreactivity in the central nervous system of this species suggests that corazonin may act as a neurohormone. Mass spectrometric analysis revealed that [Arg(7)]-corazonin was the only isoform of the neuropeptide present in T. infestans tissue samples.
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FMRFamide-like immunocytochemistry in the brain and subesophageal ganglion of Triatoma infestans (Insecta: Heteroptera). Coexpression with β-pigment-dispersing hormone and small cardioactive peptide B
Cell and Tissue Research, 2005Co-Authors: Beatriz P Settembrini, Marcelo J VillarAbstract:The distribution of FMRFamide (FMRFa)-like immunoreactivity (LI) was studied in the brain and subesophageal ganglion of Triatoma infestans, the insect vector of Chagas’ disease. The neuropeptide displayed a widespread distribution with immunostained somata in the optic lobe, in the anterior, lateral, and posterior soma rinds of the protocerebrum, and around the antennal sensory and mechanosensory and motor neuropils of the deutocerebrum. FMRFa-immunoreactive profiles of the subesophageal ganglion were seen in the mandibular, maxillary, and labial Neuromeres. Immunostained neurites were detected in the medulla and lobula of the optic lobe, the lateral protocerebral neuropil, the median bundle, the calyces and the stalk of the mushroom bodies, and the central body. In the deutocerebrum, the sensory glomeruli showed a higher density of immunoreactive processes than the mechanosensory and motor neuropil, whereas the neuropils of each Neuromere of the subesophageal ganglion displayed a moderate density of immunoreactive neurites. Colocalization of FMRFa-LI and crustacean pigment-dispersing hormone-LI was found in perikarya of the proximal optic lobe, the lobula, the sensory deutocerebrum, and the labial Neuromere of the subesophageal ganglion. The distribution pattern of small cardioactive peptide B (SCPB)-LI was also widespread, with immunolabeled somata surrounding every neuropil region of the brain and subesophageal ganglion, except for the optic lobe. FMRFa- and SCPB-LIs showed extensive colocalization in the brain of this triatomine species. The presence of immunolabeled perikarya displaying either FMRFa- or SCPB-LI confirmed that each antisera identified different peptide molecules. The distribution of FMRFa immunostaining in T. infestans raises the possibility that FMRFa plays a role in the regulation of circadian rhythmicity. The finding of immunolabeling in neurosecretory somata of the protocerebrum suggests that this neuropeptide may also act as a neurohormone.
P. Sivasubramanian - One of the best experts on this subject based on the ideXlab platform.
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localization of leucokinin like immunoreactive neurons and their metamorphic changes in the ventral ganglion of the fly sarcophaga bullata
Comparative Biochemistry and Physiology Part A: Physiology, 1994Co-Authors: P. SivasubramanianAbstract:Abstract The distribution of leucokinin I-like immunoreactive neurons in the ventral ganglion of the fly Sarcophaga bullata was examined by indirect immunofluorescence. In the larval ventral ganglion there are seven pairs of large, highly immunoreactive neurons distributed ventrolaterally as bilateral pairs in abdominal Neuromeres 1–7. During metamorphosis, the seven pairs of larval immunoreactive neurons survive and three additional pairs of immunoreactive neurons appear within the condensed abdominal ganglion, bringing the total number of immunoreactive neurons to 10 pairs. It is suggested that the neuropeptide from the newly formed three pairs of leucokinin-like immunoreactive neurons may have some unique function in the life of the adult insect.
Heinrich Reichert - One of the best experts on this subject based on the ideXlab platform.
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Structure and development of the subesophageal zone of the Drosophila brain. II. Sensory compartments
The Journal of Comparative Neurology, 2017Co-Authors: Sarah Kendroud, Heinrich Reichert, Philipp A. Kuert, Simon G. Sprecher, Ali Asgar Bohra, Bao Nguyen, Oriane Guillermin, Krishnaswamy Vijayraghavan, Volker HartensteinAbstract:The subesophageal zone (SEZ) of the Drosophila brain processes mechanosensory and gustatory sensory input from sensilla located on the head, mouth cavity and trunk. Motor output from the SEZ directly controls the movements involved in feeding behavior. In an accompanying paper (Hartenstein et al., 2017) we analyzed the systems of fiber tracts and secondary lineages to establish reliable criteria for defining boundaries between the four Neuromeres of the SEZ, as well as discrete longitudinal neuropil domains within each SEZ Neuromere. Here we use this anatomical framework to systematically map the sensory projections entering the SEZ throughout development. Our findings show a continuity between larval and adult sensory neuropils. Gustatory axons from internal and external taste sensilla of the larva and adult form two closely related sensory projections, (1) the anterior central sensory center (ACSC) located deep in the ventromedial neuropil of the tritocerebrum and mandibular Neuromere, and (2) the anterior ventral sensory center (AVSC), occupying a superficial layer within the ventromedial tritocerebrum. Additional, presumed mechanosensory terminal axons entering via the labial nerve define the ventromedial sensory center (VMSC) in the maxilla and labium. Mechanosensory afferents of the massive array of chordotonal organs (Johnston's organ) of the adult antenna project into the centrolateral neuropil column of the anterior SEZ, creating the antenno-mechanosensory and motor center (AMMC). Dendritic projections of dye back-filled motor neurons extend throughout a ventral layer of the SEZ, overlapping widely with the AVSC and VMSC. Our findings elucidate fundamental structural aspects of the developing sensory systems in Drosophila. This article is protected by copyright. All rights reserved.
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Structure and development of the subesophageal zone of the Drosophila brain. I. Segmental architecture, compartmentalization, and lineage anatomy.
The Journal of Comparative Neurology, 2017Co-Authors: Volker Hartenstein, Heinrich Reichert, Jaison J. Omoto, Darren Wong, Philipp A. Kuert, Jennifer K. Lovick, Amelia Younossi-hartensteinAbstract:The subesophageal zone (SEZ) of the Drosophila brain houses the circuitry underlying feeding behavior and is involved in many other aspects of sensory processing and locomotor control. Formed by the merging of four Neuromeres, the internal architecture of the SEZ can be best understood by identifying segmentally reiterated landmarks emerging in the embryo and larva, and following the gradual changes by which these landmarks become integrated into the mature SEZ during metamorphosis. In previous works, the system of longitudinal fibers (connectives) and transverse axons (commissures) has been utilized as a scaffold that provides internal landmarks for the Neuromeres of the larval ventral nerve cord. We have extended the analysis of this scaffold to the SEZ and, in addition, reconstructed the tracts formed by lineages and nerves in relationship to the connectives and commissures. As a result we establish reliable criteria that define boundaries between the four Neuromeres (tritocerebrum; mandibular Neuromere, maxillary Neuromere, labial Neuromere) of the SEZ at all stages of development. Fascicles and lineage tracts also demarcate seven columnar neuropil domains (ventromedial, ventro-lateral; centromedial; central; centrolateral; dorsomedial; dorsolateral) identifiable throughout development. These anatomical subdivisions, presented in the form of an atlas including confocal sections and 3D digital models for the larval, pupal and adult stage, allowed us to describe the morphogenetic changes shaping the adult SEZ. Finally, we mapped MARCM-labeled clones of all secondary lineages of the SEZ to the newly established neuropil subdivisions. Our work will facilitate future studies of function and comparative anatomy of the SEZ. This article is protected by copyright. All rights reserved.
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arborization pattern of engrailed positive neural lineages reveal Neuromere boundaries in the drosophila brain neuropil
The Journal of Comparative Neurology, 2009Co-Authors: Abhilasha Kumar, Heinrich Reichert, Siaumin Fung, Robert Lichtneckert, Volker HartensteinAbstract:The Drosophila brain is a highly complex structure composed of thousands of neurons that are interconnected in numerous exquisitely organized neuropile structures such as the mushroom bodies, central complex, antennal lobes, and other specialized neuropiles. While the neurons of the insect brain are known to derive in a lineage-specific fashion from a stereotyped set of segmentally organized neuroblasts, the developmental origin and neuromeric organization of the neuropile formed by these neurons is still unclear. In this report, we use genetic labeling techniques to characterize the neuropile innervation pattern of engrailed-expressing brain lineages of known neuromeric origin. We show that the neurons of these lineages project to and form most arborizations, in particular all of their proximal branches, in the same brain neuropile compartments in embryonic, larval and adult stages. Moreover, we show that engrailed-positive neurons of differing neuromeric origin respect boundaries between Neuromere-specific compartments in the brain. This is confirmed by an analysis of the arborization pattern of empty spiracles-expressing lineages. These findings indicate that arborizations of lineages deriving from different brain Neuromeres innervate a non-overlapping set of neuropile compartments. This supports a model for Neuromere-specific brain neuropile, in which a given lineage forms its proximal arborizations predominantly in the compartments that correspond to its Neuromere of origin.
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the columnar gene vnd is required for tritocerebral Neuromere formation during embryonic brain development of drosophila
Development, 2006Co-Authors: Simon G. Sprecher, Heinrich Reichert, Rolf Urbach, Gerhard M. Technau, Filippo M Rijli, Frank HirthAbstract:In Drosophila, evolutionarily conserved transcription factors are required for the specification of neural lineages along the anteroposterior and dorsoventral axes, such as Hox genes for anteroposterior and columnar genes for dorsoventral patterning. In this report, we analyse the role of the columnar patterning gene ventral nervous system defective (vnd) in embryonic brain development. Expression of vnd is observed in specific subsets of cells in all brain Neuromeres. Loss-of-function analysis focussed on the tritocerebrum shows that inactivation of vnd results in regionalized axonal patterning defects, which are comparable with the brain phenotype caused by mutation of the Hox gene labial (lab). However, in contrast to lab activity in specifying tritocerebral neuronal identity, vnd is required for the formation and specification of tritocerebral neural lineages. Thus, in early vnd mutant embryos, the Tv1-Tv5 neuroblasts, which normally express lab, do not form. Later in embryogenesis, vnd mutants show an extensive loss of lab-expressing cells because of increased apoptotic activity, resulting in a gap-like brain phenotype that is characterized by an almost complete absence of the tritocerebral Neuromere. Correspondingly, genetic block of apoptosis in vnd mutant embryos partially restores tritocerebral cells as well as axon tracts. Taken together, our results indicate that vnd is required for the genesis and proper identity specification of tritocerebral neural lineages during embryonic brain development of Drosophila.
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ventral veins lacking is required for specification of the tritocerebrum in embryonic brain development of Drosophila.
Mechanisms of Development, 2005Co-Authors: Stefan Meier, Heinrich Reichert, Simon G. Sprecher, Frank HirthAbstract:The homeotic or Hox genes encode a network of conserved transcription factors which provide axial positional information and control segment morphology in development and evolution. During embryonic brain development of Drosophila, the Hox gene labial (lab) is essential for tritocerebral Neuromere specification; lab loss of function results in tritocerebral cells that fail to adopt a neuronal identity, causing axonal pathfinding defects. Here we present evidence that the POU-homeodomain DNA-binding protein ventral veins lacking (vvl) acts genetically downstream of lab in the specification of the tritocerebral Neuromere. In the embryonic brain, vvl expression is seen in all brain Neuromeres, including the tritocerebral lab domain. Lab mutant analysis shows that vvl expression in the tritocerebrum is dependent on lab activity. Loss-of-function analysis focussed on the tritocerebrum reveals that inactivation of vvl results in patterning defects which are comparable to the brain phenotype caused by null mutation of lab. In the absence of vvl, mutant tritocerebral cells are generated and positioned correctly, but these cells fail to express neuronal markers indicating defects in neuronal differentiation. Moreover, longitudinal axon pathways in the tritocerebrum are severely reduced or absent and the tritocerebral commissure is missing in the vvl mutant brain. Genetic rescue experiments show that vvl is able to partially replace lab in the specification of the tritocerebral Neuromere. Our results indicate that vvl acts downstream of the Hox gene lab and regulates specific aspects of neuronal differentiation within the tritocerebral Neuromere during embryonic brain development of Drosophila.
Beatriz P Settembrini - One of the best experts on this subject based on the ideXlab platform.
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distribution and characterization of corazonin in the central nervous system of triatoma infestans insecta heteroptera
Peptides, 2011Co-Authors: Beatriz P Settembrini, Daniela De Pasquale, Melissa Postal, Paulo Marcos Pinto, Celia R Carlini, Marcelo J VillarAbstract:The distribution of corazonin in the central nervous system of the heteropteran insect Triatoma infestans was studied by immunohistochemistry. The presence of corazonin isoforms was investigated using MALDI-TOF mass spectrometry in samples containing the brain, the subesophageal ganglion, the corpora cardiaca-corpus allatum complex and the anterior part of the aorta. Several groups of immunopositive perikarya were detected in the brain, the subesophageal ganglion and the thoracic ganglia. Regarding the brain, three clusters were observed in the protocerebrum. One of these clusters was formed by somata located near the entrance of the ocellar nerves whose fibers supplied the aorta and the corpora cardiaca. The remaining groups of the protocerebrum were located in the lateral soma cortex and at the boundary of the protocerebrum with the optic lobe. The optic lobe housed immunoreactive somata in the medial soma layer of the lobula and at the level of the first optic chiasma. The neuropils of the deutocerebrum and the tritocerebrum were immunostained, but no immunoreactive perikarya were detected. In the subesophageal ganglion, immunostained somata were found in the soma layers of the mandibular and labial Neuromeres, whereas in the mesothoracic ganglionic mass, they were observed in the mesothoracic, metathoracic and abdominal Neuromeres. Immunostained neurites were also found in the esophageal wall. The distribution pattern of corazonin like immunoreactivity in the central nervous system of this species suggests that corazonin may act as a neurohormone. Mass spectrometric analysis revealed that [Arg(7)]-corazonin was the only isoform of the neuropeptide present in T. infestans tissue samples.
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FMRFamide-like immunocytochemistry in the brain and subesophageal ganglion of Triatoma infestans (Insecta: Heteroptera). Coexpression with β-pigment-dispersing hormone and small cardioactive peptide B
Cell and Tissue Research, 2005Co-Authors: Beatriz P Settembrini, Marcelo J VillarAbstract:The distribution of FMRFamide (FMRFa)-like immunoreactivity (LI) was studied in the brain and subesophageal ganglion of Triatoma infestans, the insect vector of Chagas’ disease. The neuropeptide displayed a widespread distribution with immunostained somata in the optic lobe, in the anterior, lateral, and posterior soma rinds of the protocerebrum, and around the antennal sensory and mechanosensory and motor neuropils of the deutocerebrum. FMRFa-immunoreactive profiles of the subesophageal ganglion were seen in the mandibular, maxillary, and labial Neuromeres. Immunostained neurites were detected in the medulla and lobula of the optic lobe, the lateral protocerebral neuropil, the median bundle, the calyces and the stalk of the mushroom bodies, and the central body. In the deutocerebrum, the sensory glomeruli showed a higher density of immunoreactive processes than the mechanosensory and motor neuropil, whereas the neuropils of each Neuromere of the subesophageal ganglion displayed a moderate density of immunoreactive neurites. Colocalization of FMRFa-LI and crustacean pigment-dispersing hormone-LI was found in perikarya of the proximal optic lobe, the lobula, the sensory deutocerebrum, and the labial Neuromere of the subesophageal ganglion. The distribution pattern of small cardioactive peptide B (SCPB)-LI was also widespread, with immunolabeled somata surrounding every neuropil region of the brain and subesophageal ganglion, except for the optic lobe. FMRFa- and SCPB-LIs showed extensive colocalization in the brain of this triatomine species. The presence of immunolabeled perikarya displaying either FMRFa- or SCPB-LI confirmed that each antisera identified different peptide molecules. The distribution of FMRFa immunostaining in T. infestans raises the possibility that FMRFa plays a role in the regulation of circadian rhythmicity. The finding of immunolabeling in neurosecretory somata of the protocerebrum suggests that this neuropeptide may also act as a neurohormone.
Frank Hirth - One of the best experts on this subject based on the ideXlab platform.
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Expression and function of the columnar patterning gene msh in late embryonic brain development of Drosophila.
Developmental Dynamics, 2020Co-Authors: Simon G. Sprecher, Frank HirthAbstract:In Drosophila, specification of neural identity requires a network of conserved transcription factors, such as the columnar genes for dorsoventral patterning. Here, we analyze the expression and function of the columnar patterning gene muscle specific homeobox (msh) in late embryonic brain development. Expression of msh is observed in all brain Neuromeres, including neurons and neuropile glia. Functional analysis demonstrates that msh is essential for proper development of the tritocerebral Neuromere and brain neuropile glia. Thus, msh mutants display a severe loss of neural and glial tissue together with axonal patterning defects. This gap-like phenotype initially correlates with defects in neural and glial cell formation and during later embryonic development is associated with increased apoptotic activity. Taken together, our results provide evidence that the columnar patterning gene msh is required for correct tritocerebral Neuromere development, as well as for neuropile glia formation and axogenesis in embryonic brain development of Drosophila. Developmental Dynamics 235:2920–2929, 2006. © 2006 Wiley-Liss, Inc.
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the columnar gene vnd is required for tritocerebral Neuromere formation during embryonic brain development of drosophila
Development, 2006Co-Authors: Simon G. Sprecher, Heinrich Reichert, Rolf Urbach, Gerhard M. Technau, Filippo M Rijli, Frank HirthAbstract:In Drosophila, evolutionarily conserved transcription factors are required for the specification of neural lineages along the anteroposterior and dorsoventral axes, such as Hox genes for anteroposterior and columnar genes for dorsoventral patterning. In this report, we analyse the role of the columnar patterning gene ventral nervous system defective (vnd) in embryonic brain development. Expression of vnd is observed in specific subsets of cells in all brain Neuromeres. Loss-of-function analysis focussed on the tritocerebrum shows that inactivation of vnd results in regionalized axonal patterning defects, which are comparable with the brain phenotype caused by mutation of the Hox gene labial (lab). However, in contrast to lab activity in specifying tritocerebral neuronal identity, vnd is required for the formation and specification of tritocerebral neural lineages. Thus, in early vnd mutant embryos, the Tv1-Tv5 neuroblasts, which normally express lab, do not form. Later in embryogenesis, vnd mutants show an extensive loss of lab-expressing cells because of increased apoptotic activity, resulting in a gap-like brain phenotype that is characterized by an almost complete absence of the tritocerebral Neuromere. Correspondingly, genetic block of apoptosis in vnd mutant embryos partially restores tritocerebral cells as well as axon tracts. Taken together, our results indicate that vnd is required for the genesis and proper identity specification of tritocerebral neural lineages during embryonic brain development of Drosophila.
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ventral veins lacking is required for specification of the tritocerebrum in embryonic brain development of Drosophila.
Mechanisms of Development, 2005Co-Authors: Stefan Meier, Heinrich Reichert, Simon G. Sprecher, Frank HirthAbstract:The homeotic or Hox genes encode a network of conserved transcription factors which provide axial positional information and control segment morphology in development and evolution. During embryonic brain development of Drosophila, the Hox gene labial (lab) is essential for tritocerebral Neuromere specification; lab loss of function results in tritocerebral cells that fail to adopt a neuronal identity, causing axonal pathfinding defects. Here we present evidence that the POU-homeodomain DNA-binding protein ventral veins lacking (vvl) acts genetically downstream of lab in the specification of the tritocerebral Neuromere. In the embryonic brain, vvl expression is seen in all brain Neuromeres, including the tritocerebral lab domain. Lab mutant analysis shows that vvl expression in the tritocerebrum is dependent on lab activity. Loss-of-function analysis focussed on the tritocerebrum reveals that inactivation of vvl results in patterning defects which are comparable to the brain phenotype caused by null mutation of lab. In the absence of vvl, mutant tritocerebral cells are generated and positioned correctly, but these cells fail to express neuronal markers indicating defects in neuronal differentiation. Moreover, longitudinal axon pathways in the tritocerebrum are severely reduced or absent and the tritocerebral commissure is missing in the vvl mutant brain. Genetic rescue experiments show that vvl is able to partially replace lab in the specification of the tritocerebral Neuromere. Our results indicate that vvl acts downstream of the Hox gene lab and regulates specific aspects of neuronal differentiation within the tritocerebral Neuromere during embryonic brain development of Drosophila.
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Developmental defects in brain segmentation caused by mutations of the homeobox genes orthodenticle and empty spiracles in Drosophila
Neuron, 1995Co-Authors: Frank Hirth, Stavros Therianos, Thomas Loop, Walter J. Gehring, Heinrich Reichert, Katsuo Furukubo-tokunagaAbstract:We have studied the roles of the homeobox genes orthodenticle (otd) and empty spiracles (ems) in embryonic brain development of Drosophila. The embryonic brain is composed of three segmental Neuromeres. The otd gene is expressed predominantly in the anterior Neuromere; expression of ems is restricted to the two posterior Neuromeres. Mutation of otd eliminates the first (protocerebral) brain Neuromere. Mutation of ems eliminates the second (deutocerebral) and third (tritocerebral) Neuromeres. otd is also necessary for development of the dorsal protocerebrum of the adult brain. We conclude that these homeobox genes are required for the development of specific brain segments in Drosophila, and that the regionalized expression of their homologs in vertebrate brains suggests an evolutionarily conserved program for brain development.