1
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Farfán-Pira KJ, Martínez-Cuevas TI, Evans TA, Nahmad M. A cis-regulatory sequence of the selector gene vestigial drives the evolution of wing scaling in Drosophila species. J Exp Biol 2023; 226:jeb244692. [PMID: 37078652 PMCID: PMC10234621 DOI: 10.1242/jeb.244692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 04/13/2023] [Indexed: 04/21/2023]
Abstract
Scaling between specific organs and overall body size has long fascinated biologists, being a primary mechanism by which organ shapes evolve. Yet, the genetic mechanisms that underlie the evolution of scaling relationships remain elusive. Here, we compared wing and fore tibia lengths (the latter as a proxy of body size) in Drosophila melanogaster, Drosophila simulans, Drosophila ananassae and Drosophila virilis, and show that the first three of these species have roughly a similar wing-to-tibia scaling behavior. In contrast, D. virilis exhibits much smaller wings relative to their body size compared with the other species and this is reflected in the intercept of the wing-to-tibia allometry. We then asked whether the evolution of this relationship could be explained by changes in a specific cis-regulatory region or enhancer that drives expression of the wing selector gene, vestigial (vg), whose function is broadly conserved in insects and contributes to wing size. To test this hypothesis directly, we used CRISPR/Cas9 to replace the DNA sequence of the predicted Quadrant Enhancer (vgQE) from D. virilis for the corresponding vgQE sequence in the genome of D. melanogaster. Strikingly, we discovered that D. melanogaster flies carrying the D. virilis vgQE sequence have wings that are significantly smaller with respect to controls, partially shifting the intercept of the wing-to-tibia scaling relationship towards that observed in D. virilis. We conclude that a single cis-regulatory element in D. virilis contributes to constraining wing size in this species, supporting the hypothesis that scaling could evolve through genetic variations in cis-regulatory elements.
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Affiliation(s)
- Keity J. Farfán-Pira
- Department of Physiology, Biophysics and Neurosciences, Centre for Research and Advanced Studies of the National Polytechnic Institute (Cinvestav-IPN), Mexico City 07360, Mexico
| | - Teresa I. Martínez-Cuevas
- Department of Physiology, Biophysics and Neurosciences, Centre for Research and Advanced Studies of the National Polytechnic Institute (Cinvestav-IPN), Mexico City 07360, Mexico
| | - Timothy A. Evans
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR 72701, USA
| | - Marcos Nahmad
- Department of Physiology, Biophysics and Neurosciences, Centre for Research and Advanced Studies of the National Polytechnic Institute (Cinvestav-IPN), Mexico City 07360, Mexico
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2
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Ghaemi R, Acker M, Stosic A, Jacobs R, Selvaganapathy PR. Bending Drosophila larva using a microfluidic device enables imaging of its brain and nervous system at single neuronal resolution. LAB ON A CHIP 2023; 23:295-305. [PMID: 36537269 DOI: 10.1039/d2lc00775d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Single neuronal imaging of a fully intact Drosophila larva is a difficult challenge for neurosciences due to the robust digging/burrowing behaviour of the Drosophila larva and the lack of intact immobilization methods at single-neuron resolution. In this paper, for the first time, a simple microfluidic device to completely immobilize the brain and the CNS of a live, fully-functioning Drosophila larva for single neuronal imaging has been demonstrated. The design of the microfluidic device contains a unique clamping feature which pins and bends the body of the larva at 1/3rd of its length from the head. This simple twist combined with the pinning mechanism not only could stop the locomotion of the larva but also could immobilize the major movement of internal organs including the CNS. The results showed that the bent trap could keep the single neuron completely inside the field of view (FOV) (50 μm × 50 μm) over 10 min of confocal imaging. The range of motion in the x- and y-axis was approximately 8 μm and 2.5 μm, respectively. This corresponds to a range of 16% and 6% along the axis of the channel and across it compared to the size of the FOV (50 μm × 50 μm). The calcium activity of the single neurons in a 3rd instar GCaMP5 larva (Cha-Gal4/CyO; UAS-GCaMP5G/TM3) was measured while its mouth region was exposed to 20 mM sodium azide (NaN3) for 5 s. The results showed that the activity of the neurons has been statistically (p < 0.0005) increased (∼60%).
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Affiliation(s)
- Reza Ghaemi
- Department of Mechanical Engineering, McMaster University, Hamilton, ON, Canada.
| | - Meryl Acker
- Department of Biology, McMaster University, Hamilton, ON, Canada
| | - Ana Stosic
- Department of Biology, McMaster University, Hamilton, ON, Canada
| | - Roger Jacobs
- Department of Biology, McMaster University, Hamilton, ON, Canada
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3
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Velten J, Gao X, Van Nierop y Sanchez P, Domsch K, Agarwal R, Bognar L, Paulsen M, Velten L, Lohmann I. Single‐cell RNA sequencing of motoneurons identifies regulators of synaptic wiring in
Drosophila
embryos. Mol Syst Biol 2022; 18:e10255. [PMID: 35225419 PMCID: PMC8883443 DOI: 10.15252/msb.202110255] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 01/28/2022] [Accepted: 02/07/2022] [Indexed: 12/14/2022] Open
Abstract
The correct wiring of neuronal circuits is one of the most complex processes in development, since axons form highly specific connections out of a vast number of possibilities. Circuit structure is genetically determined in vertebrates and invertebrates, but the mechanisms guiding each axon to precisely innervate a unique pre‐specified target cell are poorly understood. We investigated Drosophila embryonic motoneurons using single‐cell genomics, imaging, and genetics. We show that a cell‐specific combination of homeodomain transcription factors and downstream immunoglobulin domain proteins is expressed in individual cells and plays an important role in determining cell‐specific connections between differentiated motoneurons and target muscles. We provide genetic evidence for a functional role of five homeodomain transcription factors and four immunoglobulins in the neuromuscular wiring. Knockdown and ectopic expression of these homeodomain transcription factors induces cell‐specific synaptic wiring defects that are partly phenocopied by genetic modulations of their immunoglobulin targets. Taken together, our data suggest that homeodomain transcription factor and immunoglobulin molecule expression could be directly linked and function as a crucial determinant of neuronal circuit structure.
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Affiliation(s)
- Jessica Velten
- Department of Developmental Biology Centre for Organismal Studies (COS) Heidelberg Heidelberg Germany
- The Barcelona Institute of Science and Technology Centre for Genomic Regulation (CRG) Barcelona Spain
- Flow Cytometry Core Facility European Molecular Biology Laboratory (EMBL) Heidelberg Germany
| | - Xuefan Gao
- Department of Developmental Biology Centre for Organismal Studies (COS) Heidelberg Heidelberg Germany
| | | | - Katrin Domsch
- Department of Developmental Biology Centre for Organismal Studies (COS) Heidelberg Heidelberg Germany
- Developmental Biology Erlangen‐Nürnberg University Erlangen Germany
| | - Rashi Agarwal
- Department of Developmental Biology Centre for Organismal Studies (COS) Heidelberg Heidelberg Germany
| | - Lena Bognar
- Department of Developmental Biology Centre for Organismal Studies (COS) Heidelberg Heidelberg Germany
| | - Malte Paulsen
- Flow Cytometry Core Facility European Molecular Biology Laboratory (EMBL) Heidelberg Germany
| | - Lars Velten
- The Barcelona Institute of Science and Technology Centre for Genomic Regulation (CRG) Barcelona Spain
- Universitat Pompeu Fabra (UPF) Barcelona Spain
| | - Ingrid Lohmann
- Department of Developmental Biology Centre for Organismal Studies (COS) Heidelberg Heidelberg Germany
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4
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Joshi R, Sipani R, Bakshi A. Roles of Drosophila Hox Genes in the Assembly of Neuromuscular Networks and Behavior. Front Cell Dev Biol 2022; 9:786993. [PMID: 35071230 PMCID: PMC8777297 DOI: 10.3389/fcell.2021.786993] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 12/14/2021] [Indexed: 11/13/2022] Open
Abstract
Hox genes have been known for specifying the anterior-posterior axis (AP) in bilaterian body plans. Studies in vertebrates have shown their importance in developing region-specific neural circuitry and diversifying motor neuron pools. In Drosophila, they are instrumental for segment-specific neurogenesis and myogenesis early in development. Their robust expression in differentiated neurons implied their role in assembling region-specific neuromuscular networks. In the last decade, studies in Drosophila have unequivocally established that Hox genes go beyond their conventional functions of generating cellular diversity along the AP axis of the developing central nervous system. These roles range from establishing and maintaining the neuromuscular networks to controlling their function by regulating the motor neuron morphology and neurophysiology, thereby directly impacting the behavior. Here we summarize the limited knowledge on the role of Drosophila Hox genes in the assembly of region-specific neuromuscular networks and their effect on associated behavior.
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Affiliation(s)
- Rohit Joshi
- Laboratory of Drosophila Neural Development, Centre for DNA Fingerprinting and Diagnostics (CDFD), Hyderabad, India
| | - Rashmi Sipani
- Laboratory of Drosophila Neural Development, Centre for DNA Fingerprinting and Diagnostics (CDFD), Hyderabad, India.,Graduate Studies, Manipal Academy of Higher Education, Manipal, India
| | - Asif Bakshi
- Laboratory of Drosophila Neural Development, Centre for DNA Fingerprinting and Diagnostics (CDFD), Hyderabad, India.,Graduate Studies, Manipal Academy of Higher Education, Manipal, India
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5
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Miroschnikow A, Schlegel P, Pankratz MJ. Making Feeding Decisions in the Drosophila Nervous System. Curr Biol 2020; 30:R831-R840. [DOI: 10.1016/j.cub.2020.06.036] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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6
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Miroschnikow A, Schlegel P, Schoofs A, Hueckesfeld S, Li F, Schneider-Mizell CM, Fetter RD, Truman JW, Cardona A, Pankratz MJ. Convergence of monosynaptic and polysynaptic sensory paths onto common motor outputs in a Drosophila feeding connectome. eLife 2018; 7:40247. [PMID: 30526854 PMCID: PMC6289573 DOI: 10.7554/elife.40247] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 11/17/2018] [Indexed: 12/13/2022] Open
Abstract
We reconstructed, from a whole CNS EM volume, the synaptic map of input and output neurons that underlie food intake behavior of Drosophila larvae. Input neurons originate from enteric, pharyngeal and external sensory organs and converge onto seven distinct sensory synaptic compartments within the CNS. Output neurons consist of feeding motor, serotonergic modulatory and neuroendocrine neurons. Monosynaptic connections from a set of sensory synaptic compartments cover the motor, modulatory and neuroendocrine targets in overlapping domains. Polysynaptic routes are superimposed on top of monosynaptic connections, resulting in divergent sensory paths that converge on common outputs. A completely different set of sensory compartments is connected to the mushroom body calyx. The mushroom body output neurons are connected to interneurons that directly target the feeding output neurons. Our results illustrate a circuit architecture in which monosynaptic and multisynaptic connections from sensory inputs traverse onto output neurons via a series of converging paths.
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Affiliation(s)
- Anton Miroschnikow
- Department of Molecular Brain Physiology and Behavior, LIMES Institute, University of Bonn, Bonn, Germany
| | - Philipp Schlegel
- Department of Molecular Brain Physiology and Behavior, LIMES Institute, University of Bonn, Bonn, Germany.,Department of Zoology, University of Cambridge, Cambridge, United Kingdom
| | - Andreas Schoofs
- Department of Molecular Brain Physiology and Behavior, LIMES Institute, University of Bonn, Bonn, Germany
| | - Sebastian Hueckesfeld
- Department of Molecular Brain Physiology and Behavior, LIMES Institute, University of Bonn, Bonn, Germany
| | - Feng Li
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | | | - Richard D Fetter
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States.,Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States
| | - James W Truman
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Albert Cardona
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States.,Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Michael J Pankratz
- Department of Molecular Brain Physiology and Behavior, LIMES Institute, University of Bonn, Bonn, Germany
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7
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Schoofs A, Hückesfeld S, Pankratz MJ. Serotonergic network in the subesophageal zone modulates the motor pattern for food intake in Drosophila. JOURNAL OF INSECT PHYSIOLOGY 2018; 106:36-46. [PMID: 28735009 DOI: 10.1016/j.jinsphys.2017.07.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 07/14/2017] [Accepted: 07/17/2017] [Indexed: 05/13/2023]
Abstract
The functional organization of central motor circuits underlying feeding behaviors is not well understood. We have combined electrophysiological and genetic approaches to investigate the regulatory networks upstream of the motor program underlying food intake in the Drosophila larval central nervous system. We discovered that the serotonergic network of the CNS is able to set the motor rhythm frequency of pharyngeal pumping. Pharmacological experiments verified that modulation of the feeding motor pattern is based on the release of serotonin. Classical lesion and laser based cell ablation indicated that the serotonergic neurons in the subesophageal zone represent a redundant network for motor control of larval food intake.
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Affiliation(s)
- Andreas Schoofs
- Department of Molecular Brain Physiology, Limes Institute, University of Bonn, Carl-Troll-Str. 31, 53115 Bonn, Germany.
| | - Sebastian Hückesfeld
- Department of Molecular Brain Physiology, Limes Institute, University of Bonn, Carl-Troll-Str. 31, 53115 Bonn, Germany
| | - Michael J Pankratz
- Department of Molecular Brain Physiology, Limes Institute, University of Bonn, Carl-Troll-Str. 31, 53115 Bonn, Germany
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8
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Kim D, Alvarez M, Lechuga LM, Louis M. Species-specific modulation of food-search behavior by respiration and chemosensation in Drosophila larvae. eLife 2017; 6:27057. [PMID: 28871963 PMCID: PMC5584988 DOI: 10.7554/elife.27057] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 08/08/2017] [Indexed: 12/17/2022] Open
Abstract
Animals explore their environment to encounter suitable food resources. Despite its vital importance, this behavior puts individuals at risk by consuming limited internal energy during locomotion. We have developed a novel assay to investigate how food-search behavior is organized in Drosophila melanogaster larvae dwelling in hydrogels mimicking their natural habitat. We define three main behavioral modes: resting at the gel's surface, digging while feeding near the surface, and apneic dives. In unstimulated conditions, larvae spend most of their time digging. By contrast, deep and long exploratory dives are promoted by olfactory stimulations. Hypoxia and chemical repellents impair diving. We report remarkable differences in the dig-and-dive behavior of D. melanogaster and the fruit-pest D. suzukii. The present paradigm offers an opportunity to study how sensory and physiological cues are integrated to balance the limitations of dwelling in imperfect environmental conditions and the risks associated with searching for potentially more favorable conditions.
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Affiliation(s)
- Daeyeon Kim
- EMBL-CRG Systems Biology Research Unit, Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, Barcelona, Spain.,Universitat Pompeu Fabra, Barcelona, Spain
| | - Mar Alvarez
- Nanobiosensors and Bioanalytical Applications Group, Catalan Institute of Nanoscience and Nanotechnology, CSIC and The Barcelona Institute of Science and Technology, CIBER-BBN, Barcelona, Spain
| | - Laura M Lechuga
- Nanobiosensors and Bioanalytical Applications Group, Catalan Institute of Nanoscience and Nanotechnology, CSIC and The Barcelona Institute of Science and Technology, CIBER-BBN, Barcelona, Spain
| | - Matthieu Louis
- EMBL-CRG Systems Biology Research Unit, Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, Barcelona, Spain.,Universitat Pompeu Fabra, Barcelona, Spain.,Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, United States.,Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, Santa Barbara, United States
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9
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Cropper EC, Jing J, Perkins MH, Weiss KR. Use of the Aplysia feeding network to study repetition priming of an episodic behavior. J Neurophysiol 2017; 118:1861-1870. [PMID: 28679841 DOI: 10.1152/jn.00373.2017] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 06/21/2017] [Accepted: 06/21/2017] [Indexed: 02/06/2023] Open
Abstract
Many central pattern generator (CPG)-mediated behaviors are episodic, meaning that they are not continuously ongoing; instead, there are pauses between bouts of activity. This raises an interesting possibility, that the neural networks that mediate these behaviors are not operating under "steady-state" conditions; i.e., there could be dynamic changes in motor activity as it stops and starts. Research in the feeding system of the mollusk Aplysia californica has demonstrated that this can be the case. After a pause, initial food grasping responses are relatively weak. With repetition, however, responses strengthen. In this review we describe experiments that have characterized cellular/molecular mechanisms that produce these changes in motor activity. In particular, we focus on cumulative effects of modulatory neuropeptides. Furthermore, we relate Aplysia research to work in other systems and species, and develop a hypothesis that postulates that changes in response magnitude are a reflection of an efficient feeding strategy.
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Affiliation(s)
- Elizabeth C Cropper
- Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York; and
| | - Jian Jing
- Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York; and.,State Key Laboratory of Pharmaceutical Biotechnology, Advanced Institute for Life Sciences, School of Life Sciences, Nanjing University, Nanjing, Jiangsu, China
| | - Matthew H Perkins
- Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York; and
| | - Klaudiusz R Weiss
- Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York; and
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10
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Ghaemi R, Rezai P, Nejad FR, Selvaganapathy PR. Characterization of microfluidic clamps for immobilizing and imaging of Drosophila melanogaster larva's central nervous system. BIOMICROFLUIDICS 2017; 11:034113. [PMID: 28580046 PMCID: PMC5446281 DOI: 10.1063/1.4984767] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 05/18/2017] [Indexed: 05/16/2023]
Abstract
Drosophila melanogaster is a well-established model organism to understand biological processes and study human diseases at the molecular-genetic level. The central nervous system (CNS) of Drosophila larvae is widely used as a model to study neuron development and network formation. This has been achieved by using various genetic manipulation tools such as microinjection to knock down certain genes or over-express proteins for visualizing the cellular activities. However, visualization of an intact-live neuronal response in larva's Central Nervous System (CNS) is challenging due to robust digging/burrowing behaviour that impedes neuroimaging. To address this problem, dissection is used to isolate and immobilize the CNS from the rest of the body. In order to obtain a true physiological response from the Drosophila CNS, it is important to avoid dissection, while the larva should be kept immobilized. In this paper, a series of microfluidic clamps were investigated for intact immobilization of the larva. As a result, an optimized structure for rapid mechanical immobilization of Drosophila larvae for CNS imaging was determined. The clamping and immobilization processes were characterized by imaging and movement measurement of the CNS through the expression of genetically encoded Calcium sensor GCaMP5 in all sensory and cholinergic interneurons. The optimal structure that included two 3D constrictions inside a narrowed channel considerably reduced the internal CNS capsule movements. It restricts the CNS movement to 10% of the motion from a glued larva and allows motion of only 10 ± 30 μm over 350 s immobilization which was sufficient for CNS imaging. These larva-on-a-chip platforms can be useful for studying CNS responses to sensory cues such as sound, light, chemosensory, tactile, and electric/magnetic fields.
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Affiliation(s)
- Reza Ghaemi
- Department of Mechanical Engineering, McMaster University, Hamilton, Ontario L8S 4L8, Canada
| | - Pouya Rezai
- Department of Mechanical Engineering, York University, Toronto, Ontario M3J 1P3, Canada
| | - Fatemeh Rafiei Nejad
- Department of Mechanical Engineering, McMaster University, Hamilton, Ontario L8S 4L8, Canada
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11
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Abstract
Following considerable progress on the molecular and cellular basis of taste perception in fly sensory neurons, the time is now ripe to explore how taste information, integrated with hunger and satiety, undergo a sensorimotor transformation to lead to the motor actions of feeding behavior. I examine what is known of feeding circuitry in adult flies from more than 250 years of work in larger flies and from newer work in Drosophila. I review the anatomy of the proboscis, its muscles and their functions (where known), its motor neurons, interneurons known to receive taste inputs, interneurons that diverge from taste circuitry to provide information to other circuits, interneurons from other circuits that converge on feeding circuits, proprioceptors that influence the motor control of feeding, and sites of integration of hunger and satiety on feeding circuits. In spite of the several neuron types now known, a connected pathway from taste inputs to feeding motor outputs has yet to be found. We are on the threshold of an era where these individual components will be assembled into circuits, revealing how nervous system architecture leads to the control of behavior.
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12
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Hox Function Is Required for the Development and Maintenance of the Drosophila Feeding Motor Unit. Cell Rep 2016; 14:850-860. [DOI: 10.1016/j.celrep.2015.12.077] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 11/18/2015] [Accepted: 12/15/2015] [Indexed: 11/24/2022] Open
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13
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Hückesfeld S, Schoofs A, Schlegel P, Miroschnikow A, Pankratz MJ. Localization of Motor Neurons and Central Pattern Generators for Motor Patterns Underlying Feeding Behavior in Drosophila Larvae. PLoS One 2015; 10:e0135011. [PMID: 26252658 PMCID: PMC4529123 DOI: 10.1371/journal.pone.0135011] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Accepted: 07/16/2015] [Indexed: 11/19/2022] Open
Abstract
Motor systems can be functionally organized into effector organs (muscles and glands), the motor neurons, central pattern generators (CPG) and higher control centers of the brain. Using genetic and electrophysiological methods, we have begun to deconstruct the motor system driving Drosophila larval feeding behavior into its component parts. In this paper, we identify distinct clusters of motor neurons that execute head tilting, mouth hook movements, and pharyngeal pumping during larval feeding. This basic anatomical scaffold enabled the use of calcium-imaging to monitor the neural activity of motor neurons within the central nervous system (CNS) that drive food intake. Simultaneous nerve- and muscle-recordings demonstrate that the motor neurons innervate the cibarial dilator musculature (CDM) ipsi- and contra-laterally. By classical lesion experiments we localize a set of CPGs generating the neuronal pattern underlying feeding movements to the subesophageal zone (SEZ). Lesioning of higher brain centers decelerated all feeding-related motor patterns, whereas lesioning of ventral nerve cord (VNC) only affected the motor rhythm underlying pharyngeal pumping. These findings provide a basis for progressing upstream of the motor neurons to identify higher regulatory components of the feeding motor system.
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14
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Ghaemi R, Rezai P, Iyengar BG, Selvaganapathy PR. Microfluidic devices for imaging neurological response of Drosophila melanogaster larva to auditory stimulus. LAB ON A CHIP 2015; 15:1116-22. [PMID: 25536889 DOI: 10.1039/c4lc01245c] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Two microfluidic devices (pneumatic chip and FlexiChip) have been developed for immobilization and live-intact fluorescence functional imaging of Drosophila larva's Central Nervous System (CNS) in response to controlled acoustic stimulation. The pneumatic chip is suited for automated loading/unloading and potentially allows high throughput operation for studies with a large number of larvae while the FlexiChip provides a simple and quick manual option for animal loading and is suited for smaller studies. Both chips were capable of significantly reducing the endogenous CNS movement while still allowing the study of sound-stimulated CNS activities of Drosophila 3rd instar larvae using genetically encoded calcium indicator GCaMP5. Temporal effects of sound frequency (50-5000 Hz) and intensity (95-115 dB) on CNS activities were investigated and a peak neuronal response of 200 Hz was identified. Our lab-on-chip devices can not only aid further studies of Drosophila larva's auditory responses but can be also adopted for functional imaging of CNS activities in response to other sensory cues. Auditory stimuli and the corresponding response of the CNS can potentially be used as a tool to study the effect of chemicals on the neurophysiology of this model organism.
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Affiliation(s)
- Reza Ghaemi
- Department of Mechanical Engineering, McMaster University, Hamilton, ON, Canada.
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15
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Schoofs A, Hückesfeld S, Surendran S, Pankratz MJ. Serotonergic pathways in the Drosophila larval enteric nervous system. JOURNAL OF INSECT PHYSIOLOGY 2014; 69:118-125. [PMID: 24907674 DOI: 10.1016/j.jinsphys.2014.05.022] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 05/26/2014] [Accepted: 05/28/2014] [Indexed: 06/03/2023]
Abstract
The enteric nervous system is critical for coordinating diverse feeding-related behaviors and metabolism. We have characterized a cluster of four serotonergic neurons in Drosophila larval brain: cell bodies are located in the subesophageal ganglion (SOG) whose neuronal processes project into the enteric nervous system. Electrophysiological, calcium imaging and behavioral analyses indicate a functional role of these neurons in modulating foregut motility. We suggest that the axonal projections of this serotonergic cluster may be part of a brain-gut neural pathway that is functionally analogous to the vertebrate vagus nerve.
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Affiliation(s)
- Andreas Schoofs
- Department of Molecular Brain Physiology, LIMES Institute, University of Bonn, Carl Troll Str. 31, 53115 Bonn, Germany.
| | - Sebastian Hückesfeld
- Department of Molecular Brain Physiology, LIMES Institute, University of Bonn, Carl Troll Str. 31, 53115 Bonn, Germany
| | - Sandya Surendran
- Department of Molecular Brain Physiology, LIMES Institute, University of Bonn, Carl Troll Str. 31, 53115 Bonn, Germany
| | - Michael J Pankratz
- Department of Molecular Brain Physiology, LIMES Institute, University of Bonn, Carl Troll Str. 31, 53115 Bonn, Germany.
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16
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Schoofs A, Hückesfeld S, Schlegel P, Miroschnikow A, Peters M, Zeymer M, Spieß R, Chiang AS, Pankratz MJ. Selection of motor programs for suppressing food intake and inducing locomotion in the Drosophila brain. PLoS Biol 2014; 12:e1001893. [PMID: 24960360 PMCID: PMC4068981 DOI: 10.1371/journal.pbio.1001893] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Accepted: 05/15/2014] [Indexed: 12/20/2022] Open
Abstract
Central mechanisms by which specific motor programs are selected to achieve meaningful behaviors are not well understood. Using electrophysiological recordings from pharyngeal nerves upon central activation of neurotransmitter-expressing cells, we show that distinct neuronal ensembles can regulate different feeding motor programs. In behavioral and electrophysiological experiments, activation of 20 neurons in the brain expressing the neuropeptide hugin, a homolog of mammalian neuromedin U, simultaneously suppressed the motor program for food intake while inducing the motor program for locomotion. Decreasing hugin neuropeptide levels in the neurons by RNAi prevented this action. Reducing the level of hugin neuronal activity alone did not have any effect on feeding or locomotion motor programs. Furthermore, use of promoter-specific constructs that labeled subsets of hugin neurons demonstrated that initiation of locomotion can be separated from modulation of its motor pattern. These results provide insights into a neural mechanism of how opposing motor programs can be selected in order to coordinate feeding and locomotive behaviors.
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Affiliation(s)
- Andreas Schoofs
- Molecular Brain Physiology and Behavior, LIMES-Institute, University of Bonn, Germany
| | - Sebastian Hückesfeld
- Molecular Brain Physiology and Behavior, LIMES-Institute, University of Bonn, Germany
| | - Philipp Schlegel
- Molecular Brain Physiology and Behavior, LIMES-Institute, University of Bonn, Germany
| | - Anton Miroschnikow
- Molecular Brain Physiology and Behavior, LIMES-Institute, University of Bonn, Germany
| | - Marc Peters
- Molecular Brain Physiology and Behavior, LIMES-Institute, University of Bonn, Germany
| | - Malou Zeymer
- Molecular Brain Physiology and Behavior, LIMES-Institute, University of Bonn, Germany
| | - Roland Spieß
- Department of Forensic Entomology, Institute of Legal Medicine, Jena University Hospital, Germany
| | - Ann-Shyn Chiang
- Brain Research Center, National Tsing Hua University, Taiwan
| | - Michael J. Pankratz
- Molecular Brain Physiology and Behavior, LIMES-Institute, University of Bonn, Germany
- * E-mail:
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17
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Abstract
The serotonergic feeding circuit in Drosophila melanogaster larvae can be used to investigate neuronal substrates of critical importance during the development of the circuit. Using the functional output of the circuit, feeding, changes in the neuronal architecture of the stomatogastric system can be visualized. Feeding behavior can be recorded by observing the rate of retraction of the mouth hooks, which receive innervation from the brain. Locomotor behavior is used as a physiological control for feeding, since larvae use their mouth hooks to traverse across an agar substrate. Changes in feeding behavior can be correlated with the axonal architecture of the neurites innervating the gut. Using immunohistochemistry it is possible to visualize and quantitate these changes. Improper handling of the larvae during behavior paradigms can alter data as they are very sensitive to manipulations. Proper imaging of the neurite architecture innervating the gut is critical for precise quantitation of number and size of varicosities as well as the extent of branch nodes. Analysis of most circuits allow only for visualization of neurite architecture or behavioral effects; however, this model allows one to correlate the functional output of the circuit with the impairments in neuronal architecture.
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Affiliation(s)
- Parag K Bhatt
- Department of Pharmacological and Physiological Science, Saint Louis University School of Medicine
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18
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Abstract
Rhythmic motor behaviors such as feeding are driven by neural networks that can be modulated by external stimuli and internal states. In Drosophila, ingestion is accomplished by a pump that draws fluid into the esophagus. Here we examine how pumping is regulated and characterize motor neurons innervating the pump. Frequency of pumping is not affected by sucrose concentration or hunger but is altered by fluid viscosity. Inactivating motor neurons disrupts pumping and ingestion, whereas activating them elicits arrhythmic pumping. These motor neurons respond to taste stimuli and show prolonged activity to palatable substances. This work describes an important component of the neural circuit for feeding in Drosophila and is a step toward understanding the rhythmic activity producing ingestion.
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19
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Khesroshahi ND, Wessalowski U, Ulama T, Niederegger S, Heinzel HG, Spiess R. Gustatory feedback affects feeding related motor pattern generation in starved 3rd instar larvae of Calliphora vicina. JOURNAL OF INSECT PHYSIOLOGY 2011; 57:872-880. [PMID: 21453707 DOI: 10.1016/j.jinsphys.2011.03.021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Revised: 03/16/2011] [Accepted: 03/18/2011] [Indexed: 05/30/2023]
Abstract
Gustatory feedback allows animals to distinguish between edible and noxious food and adapts centrally generated feeding motor patterns to environmental demands. In reduced preparations obtained from starved Calliphora larvae, putatively appetitive (ethanol), aversive (sodium acetate) and neutral (glucose) gustatory stimuli were applied to the anterior sense organs. The resulting sensory response was recorded from the maxillary and antennal nerves. All three stimuli increased the neural activity in both nerves. Recordings obtained from the antennal nerve to monitor the activation pattern of the cibarial dilator muscles, demonstrated an effect of gustatory input on the central pattern generator for feeding. Ethanol consistently enhanced the rhythmic activity of the CDM motor neurons either by speeding up the rhythm or by increasing the burst duration. Ethanol also had an enhancing effect on the motor patterns of a protractor muscle which moves the cephalopharyngeal skeleton relative to the body. Sodium acetate showed a state dependent effect: in preparations without spontaneous CDM activity it initiated rhythmic motor patterns, while an ongoing CDM rhythm was inhibited. Surprisingly glucose had an enhancing effect which was less pronounced than that of ethanol. Gustatory feedback therefore can modify and adapt the motor output of the multifunctional central pattern generator for feeding.
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Affiliation(s)
- Nasim Dokani Khesroshahi
- Zoologisches Institut der Universität Bonn, Abteilung Neurobiologie, Poppelsdorfer Schloß, 53115 Bonn, Germany.
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20
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Niederegger S, Wartenberg N, Spieß R, Mall G. Simple clearing technique as species determination tool in blowfly larvae. Forensic Sci Int 2011; 206:e96-8. [PMID: 21306846 DOI: 10.1016/j.forsciint.2011.01.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Revised: 12/17/2010] [Accepted: 01/12/2011] [Indexed: 10/18/2022]
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21
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Hückesfeld S, Niederegger S, Schlegel P, Heinzel HG, Spiess R. Feel the heat: The effect of temperature on development, behavior and central pattern generation in 3rd instar Calliphora vicina larvae. JOURNAL OF INSECT PHYSIOLOGY 2011; 57:136-146. [PMID: 20965195 DOI: 10.1016/j.jinsphys.2010.10.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2010] [Revised: 10/11/2010] [Accepted: 10/11/2010] [Indexed: 05/30/2023]
Abstract
Like in all poikilothermic animals, higher temperatures increase developmental rate and activity in Calliphora vicina larvae. We therefore could expect temperature to have a persistent effect on the output of the feeding and crawling central pattern generators (CPGs). When confronted with a steep temperature gradient, larvae show evasive behavior after touching the substrate with the cephalic sense organs. Beside this reflex behavior the terminal- and dorsal organ might also mediate long term CPG modulation. Both organs were thermally stimulated while their response was recorded from the maxillary- or antennal nerve. The terminal organ showed a tonic response characteristic while the dorsal organ was not sensitive to temperature. Thermal stimulation of the terminal organ did not affect the ongoing patterns of fictive feeding or crawling, recorded from the antennal- or abdominal nerve respectively. A selective increase of the central nervous system (CNS) temperature accelerated the motor patterns of both feeding and crawling. We propose that temperature affects centrally generated behavior via two pathways: short term changes like thermotaxis are mediated by the terminal organ, while long term adaptations like increased feeding rate are caused by temperature sensitive neurons in the CNS which were recently shown to exist in Drosophila larvae.
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Affiliation(s)
- Sebastian Hückesfeld
- Zoologisches Institut der Universität Bonn, Abteilung Neurobiologie, Poppelsdorfer Schloß, 53115 Bonn, Germany
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22
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Newquist G. Brain organization and the roots of anticipation in Drosophila olfactory conditioning. Neurosci Biobehav Rev 2010; 35:1166-74. [PMID: 21168436 DOI: 10.1016/j.neubiorev.2010.12.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Revised: 12/09/2010] [Accepted: 12/10/2010] [Indexed: 11/16/2022]
Abstract
Defining learning at the molecular and physiological level has been one of the greatest challenges in biology. Recent research suggests that by studying fruit fly (Drosophila melanogaster) brain organization we can now begin to unravel some of these mysteries. The fruit fly brain is organized into executive centers that regulate anatomically separate behavioral systems. The mushroom body is an example of an executive center which is modified by olfactory conditioning. During this simple form of learning, an odor is paired with either food or shock. Either experience alters distinguishable specific circuitry within the mushroom body. Results suggest that after conditioning an odor to food, the mushroom body will activate a feeding system via a subset of its circuitry. After conditioning an odor to shock, the mushroom body will instead activate an avoidance system with other subsets of mushroom body neurons. The results of these experiments demonstrate a mechanism for flies to display anticipation of their environment after olfactory conditioning has occurred. However, these results fail to provide evidence for reinforcement, a consequence of action, as part of this mechanism. Instead, specific subsets of dopaminergic and octopaminergic neurons provide a simple pairing signal, in contrast to a reinforcement signal, which allows for prediction of the environment after experience. This view has implications for models of conditioning.
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Affiliation(s)
- Gunnar Newquist
- Cell and Molecular Biology Program, Department of Biology, University of Nevada, Reno, NV 89557, United States.
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23
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Hückesfeld S, Niederegger S, Heinzel HG, Spiess R. The cephalic and pharyngeal sense organs of Calliphora vicina 3rd instar larvae are mechanosensitive but have no profound effect on ongoing feeding related motor patterns. JOURNAL OF INSECT PHYSIOLOGY 2010; 56:1530-1541. [PMID: 20493875 DOI: 10.1016/j.jinsphys.2010.05.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2010] [Revised: 04/30/2010] [Accepted: 05/03/2010] [Indexed: 05/29/2023]
Abstract
The anterior segments of cyclorraphous Diptera larvae bear various sense organs: the dorsal- and terminal organ located on the cephalic lobes, the ventral- and labial organs associated with the mouthplate and the internal labral organ which lies on the dorsal surface of the esophagus. The sense organs are connected to the brain via the antennal nerve (dorsal- and labral organ) or the maxillary nerve (terminal-, ventral-, labial organ). Although their ultrastructure suggests also a mechanosensory function only their response to olfactory and gustatory stimuli has been investigated electrophysiologically. Here we stimulated the individual organs with step-, ramp-, and sinusoidal stimuli of different amplitude while extracellulary recording their afferents from the respective nerves. The external organs show a threshold of approximately 2 microm. All organs responded phasically and did not habituate to repetitive stimuli. The low threshold of the external organs combined with their rhythmically exposure to the substrate suggested a putative role in the temporal coordination of feeding. We therefore repetitively stimulated individual organs while simultaneously monitoring the centrally generated motor pattern for food ingestion. Neither the dorsal-, terminal- or ventral organ afferents had an obvious effect on the ongoing motor rhythm. Various reasons explaining these results are discussed.
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Affiliation(s)
- Sebastian Hückesfeld
- Zoologisches Institut der Universität Bonn, Abteilung Neurobiologie, Bonn, Germany
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