The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform
Maxwell G Heiman - One of the best experts on this subject based on the ideXlab platform.
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ordered arrangement of Dendrites within a c elegans sensory nerve bundle
eLife, 2018Co-Authors: Maxwell G HeimanAbstract:: Biological systems are organized into well-ordered structures and can evolve new patterns when perturbed. To identify principles underlying biological order, we turned to C. elegans for its simple anatomy and powerful genetics. We developed a method to quantify the arrangement of three Dendrites in the main sensory nerve bundle, and found that they exhibit a stereotyped arrangement throughout larval growth. Dendrite order does not require prominent features including sensory cilia and glial junctions. In contrast, loss of the cell adhesion molecule (CAM) CDH-4/Fat-like cadherin causes Dendrites to be ordered randomly, despite remaining bundled. Loss of the CAMs PTP-3/LAR or SAX-7/L1CAM causes Dendrites to adopt an altered order, which becomes increasingly random as animals grow. Misexpression of SAX-7 leads to subtle but reproducible changes in dendrite order. Our results suggest that combinations of CAMs allow Dendrites to self-organize into a stereotyped arrangement and can produce altered patterns when perturbed.
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ordered arrangement of Dendrites within a c elegans sensory nerve bundle
bioRxiv, 2018Co-Authors: Maxwell G HeimanAbstract:Biological systems are organized into well-ordered structures and can evolve new patterns when perturbed. To identify principles underlying biological order, we turned to C. elegans for its simple anatomy and powerful genetics. We developed a method to quantify the arrangement of three Dendrites in the main sensory nerve bundle, and found that they exhibit a stereotyped arrangement throughout larval growth. Dendrite order does not require prominent features including sensory cilia and glial junctions. In contrast, loss of the cell adhesion molecule (CAM) CDH-4/Fat-like cadherin causes Dendrites to be ordered randomly, despite remaining bundled. Loss of the CAMs PTP-3/LAR or SAX-7/L1CAM causes Dendrites to adopt an altered order, which becomes increasingly random as animals grow. Misexpression of SAX-7 leads to subtle but reproducible changes in dendrite order. Our results suggest that differential expression of CAMs allows Dendrites to self-organize into a stereotyped arrangement that readily gives rise to new patterns when perturbed.
Peter Soba - One of the best experts on this subject based on the ideXlab platform.
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Epidermis-Derived Semaphorin Promotes Dendrite Self-Avoidance by Regulating Dendrite-Substrate Adhesion in Drosophila Sensory Neurons.
Neuron, 2016Co-Authors: Shan Meltzer, Peter Soba, Smita Yadav, Susan Younger, Wei Zhang, Jay Z. ParrishAbstract:Precise patterning of dendritic arbors is critical for the wiring and function of neural circuits. Dendrite-extracellular matrix (ECM) adhesion ensures that the Dendrites of Drosophila dendritic arborization (da) sensory neurons are properly restricted in a 2D space, and thereby facilitates contact-mediated dendritic self-avoidance and tiling. However, the mechanisms regulating dendrite-ECM adhesion in vivo are poorly understood. Here, we show that mutations in the semaphorin ligand sema-2b lead to a dramatic increase in self-crossing of Dendrites due to defects in dendrite-ECM adhesion, resulting in a failure to confine Dendrites to a 2D plane. Furthermore, we find that Sema-2b is secreted from the epidermis and signals through the Plexin B receptor in neighboring neurons. Importantly, we find that Sema-2b/PlexB genetically and physically interacts with TORC2 complex, Tricornered (Trc) kinase, and integrins. These results reveal a novel role for semaphorins in dendrite patterning and illustrate how epidermal-derived cues regulate neural circuit assembly.
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integrins regulate repulsion mediated dendritic patterning of drosophila sensory neurons by restricting Dendrites in a 2d space
Neuron, 2012Co-Authors: Denan Wang, Peter SobaAbstract:Summary Dendrites of the same neuron usually avoid each other. Some neurons also repel similar neurons through dendrite-dendrite interaction to tile the receptive field. Nonoverlapping coverage based on such contact-dependent repulsion requires Dendrites to compete for limited space. Here we show that Drosophila class IV dendritic arborization (da) neurons, which tile the larval body wall, grow their Dendrites mainly in a 2D space on the extracellular matrix (ECM) secreted by the epidermis. Removing neuronal integrins or blocking epidermal laminin production causes Dendrites to grow into the epidermis, suggesting that integrin-laminin interaction attaches Dendrites to the ECM. We further show that some of the previously identified tiling mutants fail to confine Dendrites in a 2D plane. Expansion of these mutant Dendrites in three dimensions results in overlap of dendritic fields. Moreover, overexpression of integrins in these mutant neurons effectively reduces dendritic crossing and restores tiling, revealing an additional mechanism for tiling.
Rajan Ambat - One of the best experts on this subject based on the ideXlab platform.
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electrochemical migration of tin in electronics and microstructure of the Dendrites
Corrosion Science, 2011Co-Authors: Daniel Minzari, Flemming Bjerg Grumsen, Morten Stendahl Jellesen, Per Moller, Rajan AmbatAbstract:Abstract The macro-, micro-, and nano-scale morphology and structure of tin Dendrites, formed by electrochemical migration on a surface mount ceramic chip resistor having electrodes consisting of tin with small amounts of Pb (∼2 wt.%) was investigated by scanning electron microscopy and transmission electron microscopy including Energy dispersive X-ray spectroscopy and electron diffraction. The tin Dendrites were formed under 5 or 12 V potential bias in 10 ppm by weight NaCl electrolyte as a micro-droplet on the resistor during electrochemical migration experiments. The Dendrites formed were found to have heterogeneous microstructure along the growth direction, which is attributed to unstable growth conditions inside the micro-volume of electrolyte. Selected area electron diffraction showed that the Dendrites are metallic tin having sections of single crystal orientation and lead containing intermetallic particles embedded in the structure. At certain areas, the dendrite structure was found to be surrounded by an oxide crust, which is believed to be due to unstable growth conditions during the dendrite formation. The oxide layer was found to be of nanocrystalline structure, which is expected to be formed by the dehydration of the hydrated oxide originally formed in solution ex-situ in ambient air.
Miklos Antal - One of the best experts on this subject based on the ideXlab platform.
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differential distribution of diacylglycerol lipase alpha and n acylphosphatidylethanolamine specific phospholipase d immunoreactivity in the superficial spinal dorsal horn of rats
Glia, 2012Co-Authors: Zoltan Hegyi, Krisztina Hollo, Ken Mackie, Miklos AntalAbstract:It is generally accepted that the endocannabinoid system plays important roles in spinal pain processing. Although it is documented that cannabinoid-1 receptors are strongly expressed in the superficial spinal dorsal horn, the cellular distribution of enzymes that can synthesize endocannabinoid ligands is less well studied. Thus, using immunocytochemical methods at the light and electron microscopic levels, we investigated the distribution of diacylglycerol lipase-alpha (DGLα) and N-acylphosphatidylethanolamine-specific phospholipase D (NAPE-PLD), enzymes synthesizing the endocannabinoid ligands, 2-arachidonoylglycerol (2-AG) and anandamide, respectively. Positive labeling was revealed only occasionally in axon terminals, but Dendrites displayed strong immunoreactivity for both enzymes. However, the dendritic localization of DGLα and NAPE-PLD showed a remarkably different distribution. DGLα immunolabeling in dentrites was always revealed at membrane compartments in close vicinity to synapses. In contrast to this, dendritic NAPE-PLD labeling was never observed in association with synaptic contacts. In addition to Dendrites, a substantial proportion of astrocytic (immunoreactive for GFAP) and microglial (immunoreactive for CD11b) profiles were also immunolabeled for both DGLα and NAPE-PLD. Glial processes immunostained for DGLα were frequently found near to synapses in which the postsynaptic dendrite was immunoreactive for DGLα, whereas NAPE-PLD immunoreactivity on glial profiles at the vicinity of synapses was only occasionally observed. Our results suggest that both neurons and glial cells can synthesize and release 2-AG and anandamide in the superficial spinal dorsal horn. 2-AG can primarily be released by postsynaptic Dendrites and glial processes adjacent to synapses, whereas anandamide can predominantly be released from non-synaptic dendritic and glial compartments.
Denan Wang - One of the best experts on this subject based on the ideXlab platform.
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epidermal cells are the primary phagocytes in the fragmentation and clearance of degenerating Dendrites in drosophila
Neuron, 2014Co-Authors: Yuanquan Song, Denan Wang, Hui Xiao, Nathalie C FrancAbstract:During developmental remodeling, neurites destined for pruning often degenerate on-site. Physical injury also induces degeneration of neurites distal to the injury site. Prompt clearance of degenerating neurites is important for maintaining tissue homeostasis and preventing inflammatory responses. Here we show that in both dendrite pruning and dendrite injury of Drosophila sensory neurons, epidermal cells rather than hemocytes are the primary phagocytes in clearing degenerating Dendrites. Epidermal cells act via Draper-mediated recognition to facilitate dendrite degeneration and to engulf and degrade degenerating Dendrites. Using multiple dendritic membrane markers to trace phagocytosis, we show that two members of the CD36 family, croquemort (crq) and debris buster (dsb), act at distinct stages of phagosome maturation for dendrite clearance. Our finding reveals the physiological importance of coordination between neurons and their surrounding epidermis, for both dendrite fragmentation and clearance.
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integrins regulate repulsion mediated dendritic patterning of drosophila sensory neurons by restricting Dendrites in a 2d space
Neuron, 2012Co-Authors: Denan Wang, Peter SobaAbstract:Summary Dendrites of the same neuron usually avoid each other. Some neurons also repel similar neurons through dendrite-dendrite interaction to tile the receptive field. Nonoverlapping coverage based on such contact-dependent repulsion requires Dendrites to compete for limited space. Here we show that Drosophila class IV dendritic arborization (da) neurons, which tile the larval body wall, grow their Dendrites mainly in a 2D space on the extracellular matrix (ECM) secreted by the epidermis. Removing neuronal integrins or blocking epidermal laminin production causes Dendrites to grow into the epidermis, suggesting that integrin-laminin interaction attaches Dendrites to the ECM. We further show that some of the previously identified tiling mutants fail to confine Dendrites in a 2D plane. Expansion of these mutant Dendrites in three dimensions results in overlap of dendritic fields. Moreover, overexpression of integrins in these mutant neurons effectively reduces dendritic crossing and restores tiling, revealing an additional mechanism for tiling.
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Control of dendrite arborization by an Ig family member, dendrite arborization and synapse maturation 1 (Dasm1)
Proceedings of the National Academy of Sciences of the United States of America, 2004Co-Authors: Denan WangAbstract:Development of both Dendrites and axons is important for the formation of neuronal circuits, because Dendrites receive information and the axon is responsible for sending signals. In the past decade, extensive studies have revealed many molecules underlying axonal outgrowth and pathfinding. In contrast, much less is known about the molecular mechanisms that control dendrite development. Here we report the identification of an evolutionarily conserved Ig superfamily member, dendrite arborization and synapse maturation 1 (Dasm1), which plays a critical role in dendrite development. Dasm1 contains five Ig domains and two fibronectin III domains in the extracellular N terminus, a single transmembrane domain, and an intracellular C-terminal tail with a type I PDZ domain binding motif at the end. It is highly expressed in the brain and localized at the Dendrites. Suppression of Dasm1 expression in hippocampal neurons via RNA interference or expression of Dasm1 without its cytoplasmic tail specifically impairs dendrite, but not axon, outgrowth. Together with its orthologues in other species, Dasm1 defines a family of molecules likely involved specifically in dendrite arborization.