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Romussi S, Giunti S, Andersen N, De Rosa MJ. C. elegans: a prominent platform for modeling and drug screening in neurological disorders. Expert Opin Drug Discov 2024; 19:565-585. [PMID: 38509691 DOI: 10.1080/17460441.2024.2329103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 03/06/2024] [Indexed: 03/22/2024]
Abstract
INTRODUCTION Human neurodevelopmental and neurodegenerative diseases (NDevDs and NDegDs, respectively) encompass a broad spectrum of disorders affecting the nervous system with an increasing incidence. In this context, the nematode C. elegans, has emerged as a benchmark model for biological research, especially in the field of neuroscience. AREAS COVERED The authors highlight the numerous advantages of this tiny worm as a model for exploring nervous system pathologies and as a platform for drug discovery. There is a particular focus given to describing the existing models of C. elegans for the study of NDevDs and NDegDs. Specifically, the authors underscore their strong applicability in preclinical drug development. Furthermore, they place particular emphasis on detailing the common techniques employed to explore the nervous system in both healthy and diseased states. EXPERT OPINION Drug discovery constitutes a long and expensive process. The incorporation of invertebrate models, such as C. elegans, stands as an exemplary strategy for mitigating costs and expediting timelines. The utilization of C. elegans as a platform to replicate nervous system pathologies and conduct high-throughput automated assays in the initial phases of drug discovery is pivotal for rendering therapeutic options more attainable and cost-effective.
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Affiliation(s)
- Stefano Romussi
- Laboratorio de Neurobiología de Invertebrados, Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), UNS-CONICET, Bahía Blanca, Argentina
| | - Sebastián Giunti
- Laboratorio de Neurobiología de Invertebrados, Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), UNS-CONICET, Bahía Blanca, Argentina
- Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur (UNS), Bahía Blanca, Argentina
| | - Natalia Andersen
- Laboratorio de Neurobiología de Invertebrados, Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), UNS-CONICET, Bahía Blanca, Argentina
- Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur (UNS), Bahía Blanca, Argentina
| | - María José De Rosa
- Laboratorio de Neurobiología de Invertebrados, Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), UNS-CONICET, Bahía Blanca, Argentina
- Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur (UNS), Bahía Blanca, Argentina
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Banerjee N, Gang SS, Castelletto ML, Ruiz F, Hallem EA. Carbon dioxide shapes parasite-host interactions in a human-infective nematode. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.28.587273. [PMID: 38585813 PMCID: PMC10996684 DOI: 10.1101/2024.03.28.587273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Skin-penetrating nematodes infect nearly one billion people worldwide. The developmentally arrested infective larvae (iL3s) seek out hosts, invade hosts via skin penetration, and resume development inside the host in a process called activation. Activated infective larvae (iL3as) traverse the host body, ending up as parasitic adults in the small intestine. Skin-penetrating nematodes respond to many chemosensory cues, but how chemosensation contributes to host seeking, intra-host development, and intra-host navigation - three crucial steps of the parasite-host interaction - remains poorly understood. Here, we investigate the role of carbon dioxide (CO2) in promoting parasite-host interactions in the human-infective threadworm Strongyloides stercoralis. We show that S. stercoralis exhibits life-stage-specific preferences for CO2: iL3s are repelled, non-infective larvae and adults are neutral, and iL3as are attracted. CO2 repulsion in iL3s may prime them for host seeking by stimulating dispersal from host feces, while CO2 attraction in iL3as may direct worms toward high-CO2 areas of the body such as the lungs and intestine. We also identify sensory neurons that detect CO2; these neurons are depolarized by CO2 in iL3s and iL3as. In addition, we demonstrate that the receptor guanylate cyclase Ss-GCY-9 is expressed specifically in CO2-sensing neurons and is required for CO2-evoked behavior. Ss-GCY-9 also promotes activation, indicating that a single receptor can mediate both behavioral and physiological responses to CO2. Our results illuminate chemosensory mechanisms that shape the interaction between parasitic nematodes and their human hosts and may aid in the design of novel anthelmintics that target the CO2-sensing pathway.
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Affiliation(s)
- Navonil Banerjee
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095
| | - Spencer S. Gang
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095
| | - Michelle L. Castelletto
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095
| | - Felicitas Ruiz
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095
| | - Elissa A. Hallem
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095
- Lead contact
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3
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Banerjee N, Rojas Palato EJ, Shih PY, Sternberg PW, Hallem EA. Distinct neurogenetic mechanisms establish the same chemosensory valence state at different life stages in Caenorhabditis elegans. G3 (BETHESDA, MD.) 2024; 14:jkad271. [PMID: 38092065 PMCID: PMC10849362 DOI: 10.1093/g3journal/jkad271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 11/17/2023] [Indexed: 02/09/2024]
Abstract
An animal's preference for many chemosensory cues remains constant despite dramatic changes in the animal's internal state. The mechanisms that maintain chemosensory preference across different physiological contexts remain poorly understood. We previously showed that distinct patterns of neural activity and motor output are evoked by carbon dioxide (CO2) in starved adults vs dauers of Caenorhabditis elegans, despite the two life stages displaying the same preference (attraction) for CO2. However, how the distinct CO2-evoked neural dynamics and motor patterns contribute to CO2 attraction at the two life stages remained unclear. Here, using a CO2 chemotaxis assay, we show that different interneurons are employed to drive CO2 attraction at the two life stages. We also investigate the molecular mechanisms that mediate CO2 attraction in dauers vs adults. We show that insulin signaling promotes CO2 attraction in dauers but not starved adults and that different combinations of neurotransmitters and neuropeptides are used for CO2 attraction at the two life stages. Our findings provide new insight into the distinct molecular and cellular mechanisms used by C. elegans at two different life stages to generate attractive behavioral responses to CO2.
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Affiliation(s)
- Navonil Banerjee
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, CA 90095, USA
- Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA
| | - Elisa J Rojas Palato
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, CA 90095, USA
| | - Pei-Yin Shih
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
- Department of Ecology, Evolution and Environmental Biology, Columbia University, NewYork, NY 10027, USA
- Zuckerman Mind, Brain, Behavior Institute, Columbia University, NewYork, NY 10027, USA
| | - Paul W Sternberg
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Elissa A Hallem
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, CA 90095, USA
- Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA
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4
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Prakash SJ, Van Auken KM, Hill DP, Sternberg PW. Semantic representation of neural circuit knowledge in Caenorhabditis elegans. Brain Inform 2023; 10:30. [PMID: 37947958 PMCID: PMC10638142 DOI: 10.1186/s40708-023-00208-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 09/22/2023] [Indexed: 11/12/2023] Open
Abstract
In modern biology, new knowledge is generated quickly, making it challenging for researchers to efficiently acquire and synthesise new information from the large volume of primary publications. To address this problem, computational approaches that generate machine-readable representations of scientific findings in the form of knowledge graphs have been developed. These representations can integrate different types of experimental data from multiple papers and biological knowledge bases in a unifying data model, providing a complementary method to manual review for interacting with published knowledge. The Gene Ontology Consortium (GOC) has created a semantic modelling framework that extends individual functional gene annotations to structured descriptions of causal networks representing biological processes (Gene Ontology-Causal Activity Modelling, or GO-CAM). In this study, we explored whether the GO-CAM framework could represent knowledge of the causal relationships between environmental inputs, neural circuits and behavior in the model nematode C. elegans [C. elegans Neural-Circuit Causal Activity Modelling (CeN-CAM)]. We found that, given extensions to several relevant ontologies, a wide variety of author statements from the literature about the neural circuit basis of egg-laying and carbon dioxide (CO2) avoidance behaviors could be faithfully represented with CeN-CAM. Through this process, we were able to generate generic data models for several categories of experimental results. We also discuss how semantic modelling may be used to functionally annotate the C. elegans connectome. Thus, Gene Ontology-based semantic modelling has the potential to support various machine-readable representations of neurobiological knowledge.
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Affiliation(s)
- Sharan J Prakash
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Kimberly M Van Auken
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - David P Hill
- The Jackson Laboratory, Bar Harbor, ME, 04609, USA
| | - Paul W Sternberg
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, USA.
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5
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Prakash SJ, Van Auken KM, Hill DP, Sternberg PW. Semantic Representation of Neural Circuit Knowledge in Caenorhabditis elegans. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.28.538760. [PMID: 37162850 PMCID: PMC10168330 DOI: 10.1101/2023.04.28.538760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
In modern biology, new knowledge is generated quickly, making it challenging for researchers to efficiently acquire and synthesise new information from the large volume of primary publications. To address this problem, computational approaches that generate machine-readable representations of scientific findings in the form of knowledge graphs have been developed. These representations can integrate different types of experimental data from multiple papers and biological knowledge bases in a unifying data model, providing a complementary method to manual review for interacting with published knowledge. The Gene Ontology Consortium (GOC) has created a semantic modelling framework that extends individual functional gene annotations to structured descriptions of causal networks representing biological processes (Gene Ontology Causal Activity Modelling, or GO-CAM). In this study, we explored whether the GO-CAM framework could represent knowledge of the causal relationships between environmental inputs, neural circuits and behavior in the model nematode C. elegans (C. elegans Neural Circuit Causal Activity Modelling (CeN-CAM)). We found that, given extensions to several relevant ontologies, a wide variety of author statements from the literature about the neural circuit basis of egg-laying and carbon dioxide (CO2) avoidance behaviors could be faithfully represented with CeN-CAM. Through this process, we were able to generate generic data models for several categories of experimental results. We also discuss how semantic modelling may be used to functionally annotate the C. elegans connectome. Thus, Gene Ontology-based semantic modelling has the potential to support various machine-readable representations of neurobiological knowledge.
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Affiliation(s)
- Sharan J Prakash
- 1. Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Kimberly M Van Auken
- 1. Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - David P Hill
- 2. The Jackson Laboratory, Bar Harbor, ME, 04609 USA
| | - Paul W Sternberg
- 1. Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
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6
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Chaubey AH, Sojka SE, Onukwufor JO, Ezak MJ, Vandermeulen MD, Bowitch A, Vodičková A, Wojtovich AP, Ferkey DM. The Caenorhabditis elegans innexin INX-20 regulates nociceptive behavioral sensitivity. Genetics 2023; 223:iyad017. [PMID: 36753530 PMCID: PMC10319955 DOI: 10.1093/genetics/iyad017] [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: 09/03/2022] [Revised: 09/03/2022] [Accepted: 02/01/2023] [Indexed: 02/09/2023] Open
Abstract
Organisms rely on chemical cues in their environment to indicate the presence or absence of food, reproductive partners, predators, or other harmful stimuli. In the nematode Caenorhabditis elegans, the bilaterally symmetric pair of ASH sensory neurons serves as the primary nociceptors. ASH activation by aversive stimuli leads to backward locomotion and stimulus avoidance. We previously reported a role for guanylyl cyclases in dampening nociceptive sensitivity that requires an innexin-based gap junction network to pass cGMP between neurons. Here, we report that animals lacking function of the gap junction component INX-20 are hypersensitive in their behavioral response to both soluble and volatile chemical stimuli that signal through G protein-coupled receptor pathways in ASH. We find that expressing inx-20 in the ADL and AFD sensory neurons is sufficient to dampen ASH sensitivity, which is supported by new expression analysis of endogenous INX-20 tagged with mCherry via the CRISPR-Cas9 system. Although ADL does not form gap junctions directly with ASH, it does so via gap junctions with the interneuron RMG and the sensory neuron ASK. Ablating either ADL or RMG and ASK also resulted in nociceptive hypersensitivity, suggesting an important role for RMG/ASK downstream of ADL in the ASH modulatory circuit. This work adds to our growing understanding of the repertoire of ways by which ASH activity is regulated via its connectivity to other neurons and identifies a previously unknown role for ADL and RMG in the modulation of aversive behavior.
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Affiliation(s)
- Aditi H Chaubey
- Department of Biological Sciences, University at Buffalo, State University of New York, Buffalo, NY 14260, USA
| | - Savannah E Sojka
- Department of Biological Sciences, University at Buffalo, State University of New York, Buffalo, NY 14260, USA
| | - John O Onukwufor
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Meredith J Ezak
- Department of Biological Sciences, University at Buffalo, State University of New York, Buffalo, NY 14260, USA
| | - Matthew D Vandermeulen
- Department of Biological Sciences, University at Buffalo, State University of New York, Buffalo, NY 14260, USA
| | - Alexander Bowitch
- Department of Biological Sciences, University at Buffalo, State University of New York, Buffalo, NY 14260, USA
| | - Anežka Vodičková
- Department of Anesthesiology and Perioperative Medicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Andrew P Wojtovich
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY 14642, USA
- Department of Anesthesiology and Perioperative Medicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Denise M Ferkey
- Department of Biological Sciences, University at Buffalo, State University of New York, Buffalo, NY 14260, USA
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7
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Liao CP, Chiang YC, Tam WH, Chen YJ, Chou SH, Pan CL. Neurophysiological basis of stress-induced aversive memory in the nematode Caenorhabditis elegans. Curr Biol 2022; 32:5309-5322.e6. [PMID: 36455561 DOI: 10.1016/j.cub.2022.11.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 08/01/2022] [Accepted: 11/04/2022] [Indexed: 12/03/2022]
Abstract
Physiological stress induces aversive memory formation and profoundly impacts animal behavior. In C. elegans, concurrent mitochondrial disruption induces aversion to the bacteria that the animal inherently prefers, offering an experimental paradigm for studying the neural basis of aversive memory. We find that, under mitochondrial stress, octopamine secreted from the RIC modulatory neuron targets the AIY interneuron through the SER-6 receptor to trigger learned bacterial aversion. RIC responds to systemic mitochondrial stress by increasing octopamine synthesis and acts in the formation of aversive memory. AIY integrates sensory information, acts downstream of RIC, and is important for the retrieval of aversive memory. Systemic mitochondrial dysfunction induces RIC responses to bacterial cues that parallel stress induction, suggesting that physiological stress activates latent communication between RIC and the sensory neurons. These findings provide insights into the circuit and neuromodulatory mechanisms underlying stress-induced aversive memory.
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Affiliation(s)
- Chien-Po Liao
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, No. 7 Chung-Shan South Road, Taipei 10002, Taiwan; Center for Precision Medicine, College of Medicine, National Taiwan University, No. 7 Chung-Shan South Road, Taipei 10002, Taiwan
| | - Yueh-Chen Chiang
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, No. 7 Chung-Shan South Road, Taipei 10002, Taiwan; Center for Precision Medicine, College of Medicine, National Taiwan University, No. 7 Chung-Shan South Road, Taipei 10002, Taiwan
| | - Wai Hou Tam
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, No. 7 Chung-Shan South Road, Taipei 10002, Taiwan; Center for Precision Medicine, College of Medicine, National Taiwan University, No. 7 Chung-Shan South Road, Taipei 10002, Taiwan
| | - Yen-Ju Chen
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, No. 7 Chung-Shan South Road, Taipei 10002, Taiwan; Center for Precision Medicine, College of Medicine, National Taiwan University, No. 7 Chung-Shan South Road, Taipei 10002, Taiwan
| | - Shih-Hua Chou
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, No. 7 Chung-Shan South Road, Taipei 10002, Taiwan; Center for Precision Medicine, College of Medicine, National Taiwan University, No. 7 Chung-Shan South Road, Taipei 10002, Taiwan
| | - Chun-Liang Pan
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, No. 7 Chung-Shan South Road, Taipei 10002, Taiwan; Center for Precision Medicine, College of Medicine, National Taiwan University, No. 7 Chung-Shan South Road, Taipei 10002, Taiwan.
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8
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Servello FA, Fernandes R, Eder M, Harris N, Martin OMF, Oswal N, Lindberg A, Derosiers N, Sengupta P, Stroustrup N, Apfeld J. Neuronal temperature perception induces specific defenses that enable C. elegans to cope with the enhanced reactivity of hydrogen peroxide at high temperature. eLife 2022; 11:e78941. [PMID: 36226814 PMCID: PMC9635881 DOI: 10.7554/elife.78941] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 10/12/2022] [Indexed: 11/30/2022] Open
Abstract
Hydrogen peroxide is the most common reactive chemical that organisms face on the microbial battlefield. The rate with which hydrogen peroxide damages biomolecules required for life increases with temperature, yet little is known about how organisms cope with this temperature-dependent threat. Here, we show that Caenorhabditis elegans nematodes use temperature information perceived by sensory neurons to cope with the temperature-dependent threat of hydrogen peroxide produced by the pathogenic bacterium Enterococcus faecium. These nematodes preemptively induce the expression of specific hydrogen peroxide defenses in response to perception of high temperature by a pair of sensory neurons. These neurons communicate temperature information to target tissues expressing those defenses via an insulin/IGF1 hormone. This is the first example of a multicellular organism inducing their defenses to a chemical when they sense an inherent enhancer of the reactivity of that chemical.
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Affiliation(s)
| | - Rute Fernandes
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and TechnologyBarcelonaSpain
- Universitat Pompeu Fabra (UPF)BarcelonaSpain
| | - Matthias Eder
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and TechnologyBarcelonaSpain
- Universitat Pompeu Fabra (UPF)BarcelonaSpain
| | - Nathan Harris
- Department of Biology, Brandeis UniversityWalthamUnited States
| | - Olivier MF Martin
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and TechnologyBarcelonaSpain
- Universitat Pompeu Fabra (UPF)BarcelonaSpain
| | - Natasha Oswal
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and TechnologyBarcelonaSpain
- Universitat Pompeu Fabra (UPF)BarcelonaSpain
| | - Anders Lindberg
- Biology Department, Northeastern UniversityBostonUnited States
| | | | - Piali Sengupta
- Department of Biology, Brandeis UniversityWalthamUnited States
| | - Nicholas Stroustrup
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and TechnologyBarcelonaSpain
- Universitat Pompeu Fabra (UPF)BarcelonaSpain
| | - Javier Apfeld
- Biology Department, Northeastern UniversityBostonUnited States
- Bioengineering Department, Northeastern UniversityBostonUnited States
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9
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Yu YV, Xue W, Chen Y. Multisensory Integration in Caenorhabditis elegans in Comparison to Mammals. Brain Sci 2022; 12:brainsci12101368. [PMID: 36291302 PMCID: PMC9599712 DOI: 10.3390/brainsci12101368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 09/28/2022] [Accepted: 10/03/2022] [Indexed: 11/30/2022] Open
Abstract
Multisensory integration refers to sensory inputs from different sensory modalities being processed simultaneously to produce a unitary output. Surrounded by stimuli from multiple modalities, animals utilize multisensory integration to form a coherent and robust representation of the complex environment. Even though multisensory integration is fundamentally essential for animal life, our understanding of the underlying mechanisms, especially at the molecular, synaptic and circuit levels, remains poorly understood. The study of sensory perception in Caenorhabditis elegans has begun to fill this gap. We have gained a considerable amount of insight into the general principles of sensory neurobiology owing to C. elegans’ highly sensitive perceptions, relatively simple nervous system, ample genetic tools and completely mapped neural connectome. Many interesting paradigms of multisensory integration have been characterized in C. elegans, for which input convergence occurs at the sensory neuron or the interneuron level. In this narrative review, we describe some representative cases of multisensory integration in C. elegans, summarize the underlying mechanisms and compare them with those in mammalian systems. Despite the differences, we believe C. elegans is able to provide unique insights into how processing and integrating multisensory inputs can generate flexible and adaptive behaviors. With the emergence of whole brain imaging, the ability of C. elegans to monitor nearly the entire nervous system may be crucial for understanding the function of the brain as a whole.
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Affiliation(s)
- Yanxun V. Yu
- Department of Neurology, Medical Research Institute, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan 430070, China
- Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan 430070, China
- Correspondence: or
| | - Weikang Xue
- Department of Neurology, Medical Research Institute, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan 430070, China
| | - Yuanhua Chen
- Department of Neurology, Medical Research Institute, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan 430070, China
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10
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Mendez P, Walsh B, Hallem EA. Using newly optimized genetic tools to probe Strongyloides sensory behaviors. Mol Biochem Parasitol 2022; 250:111491. [PMID: 35697205 PMCID: PMC9339661 DOI: 10.1016/j.molbiopara.2022.111491] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 05/25/2022] [Accepted: 06/07/2022] [Indexed: 11/26/2022]
Abstract
The oft-neglected human-parasitic threadworm, Strongyloides stercoralis, infects roughly eight percent of the global population, placing disproportionate medical and economic burden upon marginalized communities. While current chemotherapies treat strongyloidiasis, disease recrudescence and the looming threat of anthelminthic resistance necessitate novel strategies for nematode control. Throughout its life cycle, S. stercoralis relies upon sensory cues to aid in environmental navigation and coordinate developmental progression. Odorants, tastants, gases, and temperature have been shown to shape parasite behaviors that drive host seeking and infectivity; however, many of these sensory behaviors remain poorly understood, and their underlying molecular and neural mechanisms are largely uncharacterized. Disruption of sensory circuits essential to parasitism presents a promising strategy for future interventions. In this review, we describe our current understanding of sensory behaviors - namely olfactory, gustatory, gas sensing, and thermosensory behaviors - in Strongyloides spp. We also highlight the ever-growing cache of genetic tools optimized for use in Strongyloides that have facilitated these findings, including transgenesis, CRISPR/Cas9-mediated mutagenesis, RNAi, chemogenetic neuronal silencing, and the use of fluorescent biosensors to measure neuronal activity. Bolstered by these tools, we are poised to enter an era of rapid discovery in Strongyloides sensory neurobiology, which has the potential to shape pioneering advances in the prevention and treatment of strongyloidiasis.
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Affiliation(s)
- Patricia Mendez
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA, USA; Molecular Biology Interdepartmental PhD Program, University of California Los Angeles, Los Angeles, CA, USA.
| | - Breanna Walsh
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA, USA; Molecular Biology Interdepartmental PhD Program, University of California Los Angeles, Los Angeles, CA, USA; Medical Scientist Training Program, University of California, Los Angeles, Los Angeles, CA, USA.
| | - Elissa A Hallem
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA, USA; Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA, USA.
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11
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Aoki I, Jurado P, Nawa K, Kondo R, Yamashiro R, Matsuyama HJ, Ferrer I, Nakano S, Mori I. OLA-1, an Obg-like ATPase, integrates hunger with temperature information in sensory neurons in C. elegans. PLoS Genet 2022; 18:e1010219. [PMID: 35675262 PMCID: PMC9176836 DOI: 10.1371/journal.pgen.1010219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2019] [Accepted: 04/26/2022] [Indexed: 11/18/2022] Open
Abstract
Animals detect changes in both their environment and their internal state and modify their behavior accordingly. Yet, it remains largely to be clarified how information of environment and internal state is integrated and how such integrated information modifies behavior. Well-fed C. elegans migrates to past cultivation temperature on a thermal gradient, which is disrupted when animals are starved. We recently reported that the neuronal activities synchronize between a thermosensory neuron AFD and an interneuron AIY, which is directly downstream of AFD, in well-fed animals, while this synchrony is disrupted in starved animals. However, it remained to be determined whether the disruption of the synchrony is derived from modulation of the transmitter release from AFD or from the modification of reception or signal transduction in AIY. By performing forward genetics on a transition of thermotaxis behavior along starvation, we revealed that OLA-1, an Obg-like ATPase, functions in AFD to promote disruption of AFD-AIY synchrony and behavioral transition. Our results suggest that the information of hunger is delivered to the AFD thermosensory neuron and gates transmitter release from AFD to disrupt thermotaxis, thereby shedding light onto a mechanism for the integration of environmental and internal state to modulate behavior.
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Affiliation(s)
- Ichiro Aoki
- Group of Molecular Neurobiology, Neuroscience Institute, Graduate School of Science, Nagoya University, Nagoya, Japan
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan
| | - Paola Jurado
- Group of Molecular Neurobiology, Neuroscience Institute, Graduate School of Science, Nagoya University, Nagoya, Japan
- Cancer Area, Institut d’Investigació Biomèdica de Bellvitge, Barcelona, Spain
| | - Kanji Nawa
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan
| | - Rumi Kondo
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan
| | - Riku Yamashiro
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan
| | - Hironori J. Matsuyama
- Group of Molecular Neurobiology, Neuroscience Institute, Graduate School of Science, Nagoya University, Nagoya, Japan
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan
| | - Isidre Ferrer
- Neuroscience Area, Institut d’Investigació Biomèdica de Bellvitge, Barcelona, Spain
| | - Shunji Nakano
- Group of Molecular Neurobiology, Neuroscience Institute, Graduate School of Science, Nagoya University, Nagoya, Japan
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan
| | - Ikue Mori
- Group of Molecular Neurobiology, Neuroscience Institute, Graduate School of Science, Nagoya University, Nagoya, Japan
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan
- * E-mail:
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12
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Riedl J, Fieseler C, Zimmer M. Tyraminergic corollary discharge filters reafferent perception in a chemosensory neuron. Curr Biol 2022; 32:3048-3058.e6. [PMID: 35690069 DOI: 10.1016/j.cub.2022.05.051] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 05/10/2022] [Accepted: 05/18/2022] [Indexed: 12/25/2022]
Abstract
Interpreting sensory information requires its integration with the current behavior of the animal. However, how motor-related circuits influence sensory information processing is incompletely understood. Here, we report that current locomotor state directly modulates the activity of BAG CO2 sensory neurons in Caenorhabditis elegans. By recording neuronal activity in animals freely navigating CO2 landscapes, we found that during reverse crawling states, BAG activity is suppressed by tyraminergic corollary discharge signaling. We provide genetic evidence that tyramine released from the RIM reversal interneurons extrasynaptically activates the inhibitory chloride channel LGC-55 in BAG. Disrupting this pathway genetically leads to excessive behavioral responses to CO2 stimuli. Moreover, we find that LGC-55 signaling cancels out perception of self-produced CO2 and O2 stimuli when animals reverse into their own gas plume in ethologically relevant aqueous environments. Our results show that sensorimotor integration involves corollary discharge signals directly modulating chemosensory neurons.
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Affiliation(s)
- Julia Riedl
- Department of Neuroscience and Developmental Biology, Vienna BioCenter (VBC), University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria
| | - Charles Fieseler
- Department of Neuroscience and Developmental Biology, Vienna BioCenter (VBC), University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria
| | - Manuel Zimmer
- Department of Neuroscience and Developmental Biology, Vienna BioCenter (VBC), University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria; Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria.
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13
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Smoot J, Padilla S, Farraj AK. The utility of alternative models in particulate matter air pollution toxicology. Curr Res Toxicol 2022; 3:100077. [PMID: 35676914 PMCID: PMC9168130 DOI: 10.1016/j.crtox.2022.100077] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 05/04/2022] [Accepted: 05/25/2022] [Indexed: 11/29/2022] Open
Abstract
Countless unique particulate matter (PM) samples with limited or no toxicity information. Alternative in vivo models offer greater throughput than traditional mammalian models. Use of zebrafish, fruit flies, and nematodes in PM toxicology lacks systematic review. Their utility in PM toxicity and mechanistic research and as screening tools is reviewed.
Exposure to particulate matter (PM) air pollution increases risk of adverse human health effects. As more attention is brought to bear on the problem of PM, traditional mammalian in vivo models struggle to keep up with the risk assessment challenges posed by the countless number of unique PM samples across air sheds with limited or no toxicity information. This review examines the utility of three higher throughput, alternative, in vivo animal models in PM toxicity research: Danio rerio (zebrafish), Caenorhabditis elegans (nematode), and Drosophila melanogaster (fruit fly). These model organisms vary in basic biology, ease of handling, methods of exposure to PM, number and types of available assays, and the degree to which they mirror human biology and responsiveness, among other differences. The use of these models in PM research dates back over a decade, with assessments of the toxicity of various PM sources including traffic-related combustion emissions, wildland fire smoke, and coal fly ash. This article reviews the use of these alternative model organisms in PM toxicity studies, their biology, the various assays developed, endpoints measured, their strengths and limitations, as well as their potential role in PM toxicity assessment and mechanistic research going forward.
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Affiliation(s)
- Jacob Smoot
- Oak Ridge Institute for Science and Education, Oak Ridge, TN, United States
| | - Stephanie Padilla
- Biomolecular and Computational Toxicology Division, Center for Computational Toxicology and Exposure, US EPA, RTP, NC, United States
| | - Aimen K. Farraj
- Public Health and Integrated Toxicology Division, US EPA, RTP, NC, United States
- Corresponding author.
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14
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Kreuzinger-Janik B, Gansfort B, Ptatscheck C. Population density, bottom-up and top-down control as an interactive triplet to trigger dispersal. Sci Rep 2022; 12:5578. [PMID: 35368038 PMCID: PMC8976845 DOI: 10.1038/s41598-022-09631-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 03/21/2022] [Indexed: 11/09/2022] Open
Abstract
AbstractDispersal reflects the trade-offs between the cost of a change in habitat and the fitness benefits conferred by that change. Many factors trigger the dispersal of animals, but in field studies they are typically not controllable; consequently, they are mostly studied in the laboratory, where their single and interactive effects on dispersal can be investigated. We tested whether three fundamental factors, population density as well as bottom-up and top-down control, influence the emigration of the nematode Caenorhabditis elegans. Nematode movement was observed in experiments conducted in two-chamber arenas in which these factors were manipulated. The results showed that both decreasing food availability and increasing population density had a positive influence on nematode dispersal. The presence of the predatory flatworm Polycelis tenuis did not consistently affect dispersal but worked as an amplifier when linked with population density with respect to certain food-supply levels. Our study indicates that nematode dispersal on small scales is non-random; rather, the worms’ ability to perceive environmental information leads to a context-dependent decision by individuals to leave or stay in a patch. The further use of nematodes to gain insights into both the triggers that initiate dispersal, and the traits of dispersing individuals will improve the modeling of animal behavior in changing and spatial heterogenous landscapes.
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15
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Feinstein JS, Gould D, Khalsa SS. Amygdala-driven apnea and the chemoreceptive origin of anxiety. Biol Psychol 2022; 170:108305. [PMID: 35271957 DOI: 10.1016/j.biopsycho.2022.108305] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 02/09/2022] [Accepted: 03/03/2022] [Indexed: 12/13/2022]
Abstract
Although the amygdala plays an important part in the pathogenesis of anxiety and generation of exteroceptive fear, recent discoveries have challenged the directionality of this brain-behavior relationship with respect to interoceptive fear. Here we highlight several paradoxical findings including: (1) amygdala lesion patients who experience excessive fear and panic following inhalation of carbon dioxide (CO2), (2) clinically anxious patients who have significantly smaller (rather than larger) amygdalae and a pronounced hypersensitivity toward CO2, and (3) epilepsy patients who exhibit apnea immediately following stimulation of their amygdala yet have no awareness that their breathing has stopped. The above findings elucidate an entirely novel role for the amygdala in the induction of apnea and inhibition of CO2-induced fear. Such a role is plausible given the strong inhibitory connections linking the central nucleus of the amygdala with respiratory and chemoreceptive centers in the brainstem. Based on this anatomical arrangement, we propose a model of Apnea-induced Anxiety (AiA) which predicts that recurring episodes of apnea are being unconsciously elicited by amygdala activation, resulting in transient spikes in CO2 that provoke fear and anxiety, and lead to characteristic patterns of escape and avoidance behavior in patients spanning the spectrum of anxiety. If this new conception of AiA proves to be true, and activation of the amygdala can repeatedly trigger states of apnea outside of one's awareness, then it remains possible that the chronicity of anxiety disorders is being interoceptively driven by a chemoreceptive system struggling to maintain homeostasis in the midst of these breathless states.
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Affiliation(s)
- Justin S Feinstein
- Laureate Institute for Brain Research, Tulsa, Oklahoma, USA, 74136; University of Tulsa, Oxley College of Health Sciences, Tulsa, Oklahoma, USA, 74104; University of Iowa, Department of Neurology, Iowa City, Iowa, USA, 52242.
| | - Dylan Gould
- Laureate Institute for Brain Research, Tulsa, Oklahoma, USA, 74136
| | - Sahib S Khalsa
- Laureate Institute for Brain Research, Tulsa, Oklahoma, USA, 74136; University of Tulsa, Oxley College of Health Sciences, Tulsa, Oklahoma, USA, 74104
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16
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Britz S, Markert SM, Witvliet D, Steyer AM, Tröger S, Mulcahy B, Kollmannsberger P, Schwab Y, Zhen M, Stigloher C. Structural Analysis of the Caenorhabditis elegans Dauer Larval Anterior Sensilla by Focused Ion Beam-Scanning Electron Microscopy. Front Neuroanat 2021; 15:732520. [PMID: 34819841 PMCID: PMC8607169 DOI: 10.3389/fnana.2021.732520] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 09/24/2021] [Indexed: 11/13/2022] Open
Abstract
At the end of the first larval stage, the nematode Caenorhabditis elegans developing in harsh environmental conditions is able to choose an alternative developmental path called the dauer diapause. Dauer larvae exhibit different physiology and behaviors from non-dauer larvae. Using focused ion beam-scanning electron microscopy (FIB-SEM), we volumetrically reconstructed the anterior sensory apparatus of C. elegans dauer larvae with unprecedented precision. We provide a detailed description of some neurons, focusing on structural details that were unknown or unresolved by previously published studies. They include the following: (1) dauer-specific branches of the IL2 sensory neurons project into the periphery of anterior sensilla and motor or putative sensory neurons at the sub-lateral cords; (2) ciliated endings of URX sensory neurons are supported by both ILso and AMso socket cells near the amphid openings; (3) variability in amphid sensory dendrites among dauers; and (4) somatic RIP interneurons maintain their projection into the pharyngeal nervous system. Our results support the notion that dauer larvae structurally expand their sensory system to facilitate searching for more favorable environments.
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Affiliation(s)
- Sebastian Britz
- Imaging Core Facility of the Biocenter, Theodor-Boveri-Institute, Julius-Maximilians-University, Würzburg, Germany
| | - Sebastian Matthias Markert
- Imaging Core Facility of the Biocenter, Theodor-Boveri-Institute, Julius-Maximilians-University, Würzburg, Germany
| | - Daniel Witvliet
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada
- Department of Molecular Genetics, Physiology and Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Anna Maria Steyer
- European Molecular Biology Laboratory, Cell Biology and Biophysics Unit, Heidelberg, Germany
| | - Sarah Tröger
- Imaging Core Facility of the Biocenter, Theodor-Boveri-Institute, Julius-Maximilians-University, Würzburg, Germany
| | - Ben Mulcahy
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada
- Department of Molecular Genetics, Physiology and Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Philip Kollmannsberger
- Center for Computational and Theoretical Biology, Julius-Maximilians-University, Würzburg, Germany
| | - Yannick Schwab
- European Molecular Biology Laboratory, Cell Biology and Biophysics Unit, Heidelberg, Germany
| | - Mei Zhen
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada
- Department of Molecular Genetics, Physiology and Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Christian Stigloher
- Imaging Core Facility of the Biocenter, Theodor-Boveri-Institute, Julius-Maximilians-University, Würzburg, Germany
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17
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Chauve L, Hodge F, Murdoch S, Masoudzadeh F, Mann HJ, Lopez-Clavijo AF, Okkenhaug H, West G, Sousa BC, Segonds-Pichon A, Li C, Wingett SW, Kienberger H, Kleigrewe K, de Bono M, Wakelam MJO, Casanueva O. Neuronal HSF-1 coordinates the propagation of fat desaturation across tissues to enable adaptation to high temperatures in C. elegans. PLoS Biol 2021; 19:e3001431. [PMID: 34723964 PMCID: PMC8585009 DOI: 10.1371/journal.pbio.3001431] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 11/11/2021] [Accepted: 09/29/2021] [Indexed: 11/18/2022] Open
Abstract
To survive elevated temperatures, ectotherms adjust the fluidity of membranes by fine-tuning lipid desaturation levels in a process previously described to be cell autonomous. We have discovered that, in Caenorhabditis elegans, neuronal heat shock factor 1 (HSF-1), the conserved master regulator of the heat shock response (HSR), causes extensive fat remodeling in peripheral tissues. These changes include a decrease in fat desaturase and acid lipase expression in the intestine and a global shift in the saturation levels of plasma membrane's phospholipids. The observed remodeling of plasma membrane is in line with ectothermic adaptive responses and gives worms a cumulative advantage to warm temperatures. We have determined that at least 6 TAX-2/TAX-4 cyclic guanosine monophosphate (cGMP) gated channel expressing sensory neurons, and transforming growth factor ß (TGF-β)/bone morphogenetic protein (BMP) are required for signaling across tissues to modulate fat desaturation. We also find neuronal hsf-1 is not only sufficient but also partially necessary to control the fat remodeling response and for survival at warm temperatures. This is the first study to show that a thermostat-based mechanism can cell nonautonomously coordinate membrane saturation and composition across tissues in a multicellular animal.
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Affiliation(s)
- Laetitia Chauve
- Epigenetics Department, Babraham Institute, Cambridge, United Kingdom
| | - Francesca Hodge
- Epigenetics Department, Babraham Institute, Cambridge, United Kingdom
| | - Sharlene Murdoch
- Epigenetics Department, Babraham Institute, Cambridge, United Kingdom
| | | | | | | | | | - Greg West
- Babraham Institute, Cambridge, United Kingdom
| | | | | | - Cheryl Li
- Epigenetics Department, Babraham Institute, Cambridge, United Kingdom
| | | | | | - Karin Kleigrewe
- Bavarian Centre for Biomolecular Mass Spectrometry, Freising, Germany
| | - Mario de Bono
- Institute of Science and Technology, Klosterneuburg, Austria
| | | | - Olivia Casanueva
- Epigenetics Department, Babraham Institute, Cambridge, United Kingdom
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18
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Vuong-Brender TT, Flynn S, Vallis Y, de Bono M. Neuronal calmodulin levels are controlled by CAMTA transcription factors. eLife 2021; 10:68238. [PMID: 34499028 PMCID: PMC8428840 DOI: 10.7554/elife.68238] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 08/28/2021] [Indexed: 01/18/2023] Open
Abstract
The ubiquitous Ca2+ sensor calmodulin (CaM) binds and regulates many proteins, including ion channels, CaM kinases, and calcineurin, according to Ca2+-CaM levels. What regulates neuronal CaM levels, is, however, unclear. CaM-binding transcription activators (CAMTAs) are ancient proteins expressed broadly in nervous systems and whose loss confers pleiotropic behavioral defects in flies, mice, and humans. Using Caenorhabditis elegans and Drosophila, we show that CAMTAs control neuronal CaM levels. The behavioral and neuronal Ca2+ signaling defects in mutants lacking camt-1, the sole C. elegans CAMTA, can be rescued by supplementing neuronal CaM. CAMT-1 binds multiple sites in the CaM promoter and deleting these sites phenocopies camt-1. Our data suggest CAMTAs mediate a conserved and general mechanism that controls neuronal CaM levels, thereby regulating Ca2+ signaling, physiology, and behavior.
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Affiliation(s)
- Thanh Thi Vuong-Brender
- Cell Biology Division, Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom.,Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria
| | - Sean Flynn
- Cell Biology Division, Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Yvonne Vallis
- Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria
| | - Mario de Bono
- Cell Biology Division, Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom
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19
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Filipowicz A, Lalsiamthara J, Aballay A. TRPM channels mediate learned pathogen avoidance following intestinal distention. eLife 2021; 10:65935. [PMID: 34032213 PMCID: PMC8177887 DOI: 10.7554/elife.65935] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 05/24/2021] [Indexed: 12/13/2022] Open
Abstract
Upon exposure to harmful microorganisms, hosts engage in protective molecular and behavioral immune responses, both of which are ultimately regulated by the nervous system. Using the nematode Caenorhabditis elegans, we show that ingestion of Enterococcus faecalis leads to a fast pathogen avoidance behavior that results in aversive learning. We have identified multiple sensory mechanisms involved in the regulation of avoidance of E. faecalis. The G-protein coupled receptor NPR-1-dependent oxygen-sensing pathway opposes this avoidance behavior, while an ASE neuron-dependent pathway and an AWB and AWC neuron-dependent pathway are directly required for avoidance. Colonization of the anterior part of the intestine by E. faecalis leads to AWB and AWC mediated olfactory aversive learning. Finally, two transient receptor potential melastatin (TRPM) channels, GON-2 and GTL-2, mediate this newly described rapid pathogen avoidance. These results suggest a mechanism by which TRPM channels may sense the intestinal distension caused by bacterial colonization to elicit pathogen avoidance and aversive learning by detecting changes in host physiology.
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Affiliation(s)
- Adam Filipowicz
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, United States
| | - Jonathan Lalsiamthara
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, United States
| | - Alejandro Aballay
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, United States
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20
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de Lima TM, Nery LEM, Maciel FE, Ngo-Vu H, Kozma MT, Derby CD. Oxygen sensing in crustaceans: functions and mechanisms. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2021; 207:1-15. [PMID: 33392718 DOI: 10.1007/s00359-020-01457-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Revised: 11/18/2020] [Accepted: 11/20/2020] [Indexed: 12/30/2022]
Abstract
Animals that live in changing environments need to adjust their metabolism to maintain body functions, and sensing these changing conditions is essential for mediating the short- and long-term physiological and behavioral responses that make these adjustments. Previous research on nematodes and insects facing changing oxygen levels has shown that these animals rapidly respond using atypical soluble guanylyl cyclases (sGCs) as oxygen sensors connected to downstream cGMP pathways, and they respond more slowly using hypoxia-inducible transcription factors (HIFs) that are further modulated by oxygen-sensing prolyl hydroxylases (PHs). Crustaceans are known to respond in different ways to hypoxia, but the mechanisms responsible for sensing oxygen levels are more poorly understood than in nematodes and insects. Our paper reviews the functions of and mechanisms underlying oxygen sensing in crustaceans. Furthermore, using the oxygen sensing abilities of nematodes and insects as guides in analyzing available crustacean transcriptomes, we identified orthologues of atypical sGCs, HIFs, and PHs in crustaceans, including in their chemosensory organs and neurons. These molecules include atypical sGCs activated by hypoxia (Gyc-88E/GCY-31 and Gyc-89D/GCY-33) but not those activated by hyperoxia (GCY-35, GCY-36), as well as orthologues of HIF-α, HIF-β, and PH. We offer possible directions for future research on oxygen sensing by crustaceans.
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Affiliation(s)
- Tábata Martins de Lima
- Programa de Pós-Graduação Em Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande, FURG, Av. Itália, Km 8, Rio Grande, RS, 96201-300, Brazil.
| | - Luiz Eduardo Maia Nery
- Programa de Pós-Graduação Em Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande, FURG, Av. Itália, Km 8, Rio Grande, RS, 96201-300, Brazil
| | - Fábio Everton Maciel
- Programa de Pós-Graduação Em Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande, FURG, Av. Itália, Km 8, Rio Grande, RS, 96201-300, Brazil
| | - Hanh Ngo-Vu
- Neuroscience Institute, Georgia State University, Atlanta, GA, USA
| | - Mihika T Kozma
- Neuroscience Institute, Georgia State University, Atlanta, GA, USA.,Department of Biology, Colorado State University, Ft. Collins, CO, USA
| | - Charles D Derby
- Neuroscience Institute, Georgia State University, Atlanta, GA, USA
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21
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Fasseas MK, Grover M, Drury F, Essmann CL, Kaulich E, Schafer WR, Barkoulas M. Chemosensory Neurons Modulate the Response to Oomycete Recognition in Caenorhabditis elegans. Cell Rep 2021; 34:108604. [PMID: 33440164 PMCID: PMC7809619 DOI: 10.1016/j.celrep.2020.108604] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 11/02/2020] [Accepted: 12/14/2020] [Indexed: 12/22/2022] Open
Abstract
Understanding how animals detect and respond to pathogen threats is central to dissecting mechanisms of host immunity. The oomycetes represent a diverse eukaryotic group infecting various hosts from nematodes to humans. We have previously shown that Caenorhabditis elegans mounts a defense response consisting of the induction of chitinase-like (chil) genes in the epidermis to combat infection by its natural oomycete pathogen Myzocytiopsis humicola. We provide here evidence that C. elegans can sense the oomycete by detecting an innocuous extract derived from animals infected with M. humicola. The oomycete recognition response (ORR) leads to changes in the cuticle and reduction in pathogen attachment, thereby increasing animal survival. We also show that TAX-2/TAX-4 function in chemosensory neurons is required for the induction of chil-27 in the epidermis in response to extract exposure. Our findings highlight that neuron-to-epidermis communication may shape responses to oomycete recognition in animal hosts. C. elegans senses its natural oomycete pathogen M. humicola without infection Exposure to a pathogen extract triggers an oomycete recognition response Upon pathogen detection, C. elegans resists infection through changes in the cuticle The response involves signaling between sensory neurons and the epidermis
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Affiliation(s)
| | - Manish Grover
- Department of Life Sciences, Imperial College, London SW7 2AZ, UK
| | - Florence Drury
- Department of Life Sciences, Imperial College, London SW7 2AZ, UK
| | - Clara L Essmann
- Department of Life Sciences, Imperial College, London SW7 2AZ, UK
| | - Eva Kaulich
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
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22
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Wolf T, Perez A, Harris G. Glutamatergic transmission regulates locomotory behavior on a food patch in C. elegans. MICROPUBLICATION BIOLOGY 2020; 2020:10.17912/micropub.biology.000332. [PMID: 33274320 PMCID: PMC7704250 DOI: 10.17912/micropub.biology.000332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Trevor Wolf
- Biology Program, 1 University Drive, California State University Channel Islands, Camarillo, Ca, 93012
| | - Ariana Perez
- Biology Program, 1 University Drive, California State University Channel Islands, Camarillo, Ca, 93012
| | - Gareth Harris
- Biology Program, 1 University Drive, California State University Channel Islands, Camarillo, Ca, 93012,
Correspondence to: Gareth Harris ()
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23
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Abstract
Microbes are ubiquitous in the natural environment of Caenorhabditis elegans. Bacteria serve as a food source for C. elegans but may also cause infection in the nematode host. The sensory nervous system of C. elegans detects diverse microbial molecules, ranging from metabolites produced by broad classes of bacteria to molecules synthesized by specific strains of bacteria. Innate recognition through chemosensation of bacterial metabolites or mechanosensation of bacteria can induce immediate behavioral responses. The ingestion of nutritive or pathogenic bacteria can modulate internal states that underlie long-lasting behavioral changes. Ingestion of nutritive bacteria leads to learned attraction and exploitation of the bacterial food source. Infection, which is accompanied by activation of innate immunity, stress responses, and host damage, leads to the development of aversive behavior. The integration of a multitude of microbial sensory cues in the environment is shaped by experience and context. Genetic, chemical, and neuronal studies of C. elegans behavior in the presence of bacteria have defined neural circuits and neuromodulatory systems that shape innate and learned behavioral responses to microbial cues. These studies have revealed the profound influence that host-microbe interactions have in governing the behavior of this simple animal host.
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Affiliation(s)
- Dennis H Kim
- Division of Infectious Diseases, Boston Children's Hospital, and Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Steven W Flavell
- Department of Brain and Cognitive Sciences, Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA, USA
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24
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C. elegans Males Integrate Food Signals and Biological Sex to Modulate State-Dependent Chemosensation and Behavioral Prioritization. Curr Biol 2020; 30:2695-2706.e4. [PMID: 32531276 DOI: 10.1016/j.cub.2020.05.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 04/15/2020] [Accepted: 05/01/2020] [Indexed: 12/13/2022]
Abstract
Dynamic integration of internal and external cues is essential for flexible, adaptive behavior. In C. elegans, biological sex and feeding state regulate expression of the food-associated chemoreceptor odr-10, contributing to plasticity in food detection and the decision between feeding and exploration. In adult hermaphrodites, odr-10 expression is high, but in well-fed adult males, odr-10 expression is low, promoting exploratory mate-searching behavior. Food-deprivation transiently activates male odr-10 expression, heightening food sensitivity and reducing food leaving. Here, we identify a neuroendocrine feedback loop that sex-specifically regulates odr-10 in response to food deprivation. In well-fed males, insulin-like (insulin/IGF-1 signaling [IIS]) and transforming growth factor β (TGF-β) signaling repress odr-10 expression. Upon food deprivation, odr-10 is directly activated by DAF-16/FoxO, the canonical C. elegans IIS effector. The TGF-β ligand DAF-7 likely acts upstream of IIS and links feeding to odr-10 only in males, due in part to the male-specific expression of daf-7 in ASJ. Surprisingly, these responses to food deprivation are not triggered by internal metabolic cues but rather by the loss of sensory signals associated with food. When males are starved in the presence of inedible food, they become nutritionally stressed, but odr-10 expression remains low and exploratory behavior is suppressed less than in starved control males. Food signals are detected by a small number of sensory neurons whose activity non-autonomously regulates daf-7 expression, IIS, and odr-10. Thus, adult C. elegans males employ a neuroendocrine feedback loop that integrates food detection and genetic sex to dynamically modulate chemoreceptor expression and influence the feeding-versus-exploration decision.
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25
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Banerjee N, Hallem EA. Decoding Inter-individual Variability in Experience-Dependent Behavioral Plasticity. Neuron 2020; 105:7-9. [PMID: 31951528 DOI: 10.1016/j.neuron.2019.12.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Inter-individual variability in behavioral flexibility is widespread throughout the animal kingdom, but its underlying mechanisms remain poorly understood. In this issue of Neuron, Beets et al. (2020) provide novel insights into the genetic basis of inter-individual differences in behavioral flexibility using the model nematode C. elegans.
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Affiliation(s)
- Navonil Banerjee
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Elissa A Hallem
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA.
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Merivee E, Must A, Nurme K, Di Giulio A, Muzzi M, Williams I, Mänd M. Neural Code for Ambient Heat Detection in Elaterid Beetles. Front Behav Neurosci 2020; 14:1. [PMID: 32116586 PMCID: PMC7016213 DOI: 10.3389/fnbeh.2020.00001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 01/03/2020] [Indexed: 11/13/2022] Open
Abstract
Environmental thermal conditions play a major role at all levels of biological organization; however, there is little information on noxious high temperature sensation crucial in behavioral thermoregulation and survival of small ectothermic animals such as insects. So far, a capability to unambiguously encode heat has been demonstrated only for the sensory triad of the spike bursting thermo- and two bimodal hygro-thermoreceptor neurons located in the antennal dome-shaped sensilla (DSS) in a carabid beetle. We used extracellular single sensillum recording in the range of 20-45°C to demonstrate that a similar sensory triad in the elaterid Agriotes obscurus also produces high temperature-induced bursty spike trains. Several parameters of the bursts are temperature dependent, allowing the neurons in a certain order to encode different, but partly overlapping ranges of heat up to lethal levels in a graded manner. ISI in a burst is the most useful parameter out of six. Our findings consider spike bursting as a general, fundamental quality of the classical sensory triad of antennal thermo- and hygro-thermoreceptor neurons widespread in many insect groups, being a flexible and reliable mode of coding unfavorably high temperatures. The possible involvement of spike bursting in behavioral thermoregulation of the beetles is discussed. By contrast, the mean firing rate of the neurons in regular and bursty spike trains combined does not carry useful thermal information at the high end of noxious heat.
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Affiliation(s)
- Enno Merivee
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Tartu, Estonia
| | - Anne Must
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Tartu, Estonia
| | - Karin Nurme
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Tartu, Estonia
| | | | - Maurizio Muzzi
- Department of Science, University of Roma Tre, Rome, Italy
| | - Ingrid Williams
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Tartu, Estonia
| | - Marika Mänd
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Tartu, Estonia
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Cebul ER, McLachlan IG, Heiman MG. Dendrites with specialized glial attachments develop by retrograde extension using SAX-7 and GRDN-1. Development 2020; 147:dev.180448. [PMID: 31988188 DOI: 10.1242/dev.180448] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 01/07/2020] [Indexed: 12/18/2022]
Abstract
Dendrites develop elaborate morphologies in concert with surrounding glia, but the molecules that coordinate dendrite and glial morphogenesis are mostly unknown. C. elegans offers a powerful model for identifying such factors. Previous work in this system examined dendrites and glia that develop within epithelia, similar to mammalian sense organs. Here, we focus on the neurons BAG and URX, which are not part of an epithelium but instead form membranous attachments to a single glial cell at the nose, reminiscent of dendrite-glia contacts in the mammalian brain. We show that these dendrites develop by retrograde extension, in which the nascent dendrite endings anchor to the presumptive nose and then extend by stretching during embryo elongation. Using forward genetic screens, we find that dendrite development requires the adhesion protein SAX-7/L1CAM and the cytoplasmic protein GRDN-1/CCDC88C to anchor dendrite endings at the nose. SAX-7 acts in neurons and glia, while GRDN-1 acts in glia to non-autonomously promote dendrite extension. Thus, this work shows how glial factors can help to shape dendrites, and identifies a novel molecular mechanism for dendrite growth by retrograde extension.
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Affiliation(s)
- Elizabeth R Cebul
- Department of Genetics, Blavatnik Institute, Harvard Medical School and Boston Children's Hospital, Boston, MA 02115, USA
| | - Ian G McLachlan
- Department of Genetics, Blavatnik Institute, Harvard Medical School and Boston Children's Hospital, Boston, MA 02115, USA
| | - Maxwell G Heiman
- Department of Genetics, Blavatnik Institute, Harvard Medical School and Boston Children's Hospital, Boston, MA 02115, USA
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Soares MV, Charão MF, Jacques MT, Dos Santos ALA, Luchese C, Pinton S, Ávila DS. Airborne toluene exposure causes germline apoptosis and neuronal damage that promotes neurobehavioural changes in Caenorhabditis elegans. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 256:113406. [PMID: 31662251 DOI: 10.1016/j.envpol.2019.113406] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 10/13/2019] [Accepted: 10/14/2019] [Indexed: 06/10/2023]
Abstract
Toluene is a highly volatile organic solvent present in gasoline. Exposure mainly occurs by absorption via the pulmonary tract and easily reaches the central nervous system, which causes toxic effects. Toluene toxicity has been described but not well established. The present work aimed to evaluate the effects of airborne exposure to toluene, the in vivo model Caenorhabditis elegans was assessed to determine whether nematode could be used to evaluate the effects of exposure to toluene and the possible mechanisms of toxicity of the solvent. Worms at the first or fourth larval stages were exposed to toluene for 48 or 24 h, respectively, in a laboratory-developed vapor chamber at concentrations of 450, 850, 1250 and 1800 ppm. We observed increases in worm mortality and significant developmental delays that occurred in a concentration-dependent manner. An increased incidence of apoptotic events in treated germline cells was shown, which was consistent with observed reductions in reproductive capacity. In addition, toluene promoted significant behavioural changes affecting swimming movements and radial locomotion, which were associated with changes in the fluorescence intensity and morphology of GABAergic and cholinergic neurons. We conclude that toluene exposure was toxic to C. elegans, with effects produced by the induction of apoptosis and neuronal damage.
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Affiliation(s)
- Marcell Valandro Soares
- Programa de Pós-Graduação em Bioquímica, Grupo de pesquisa em Bioquímica e Toxicologia em Caenorhabditis elegans (GBToxCe), Universidade Federal do Pampa, Uruguaiana, RS, 97500-970, Brazil
| | - Mariele Feiffer Charão
- Laboratório de Toxicologia Analítica, Universidade Feevale, Rua Rubem Berta, nº 200, Novo Hamburgo, CEP: 93525-090, RS, Brazil
| | - Mauricio Tavares Jacques
- Programa de Pós-Graduação em Bioquímica, Grupo de pesquisa em Bioquímica e Toxicologia em Caenorhabditis elegans (GBToxCe), Universidade Federal do Pampa, Uruguaiana, RS, 97500-970, Brazil; Laboratório de Experimentação em Neuropatologia - Departamento de Bioquímica, CCB, Universidade Federal de Santa Catarina, Bloco C, Trindade, Florianópolis, SC, CEP 88040-900, Brazil
| | - Ana Laura Anibaletto Dos Santos
- Laboratório de Toxicologia Analítica, Universidade Feevale, Rua Rubem Berta, nº 200, Novo Hamburgo, CEP: 93525-090, RS, Brazil
| | - Cristiane Luchese
- Programa de Pós-Graduação em Bioquímica e Bioprospecção, Laboratório de Pesquisa em Farmacologia Bioquímica (LaFarBio), Grupo de Pesquisa em Neurobiotecnologia (GPN), Universidade Federal de Pelotas, Pelotas, RS, 96010-900, Brazil
| | - Simone Pinton
- Programa de Pós-Graduação em Bioquímica, Grupo de pesquisa em Bioquímica e Toxicologia em Caenorhabditis elegans (GBToxCe), Universidade Federal do Pampa, Uruguaiana, RS, 97500-970, Brazil
| | - Daiana Silva Ávila
- Programa de Pós-Graduação em Bioquímica, Grupo de pesquisa em Bioquímica e Toxicologia em Caenorhabditis elegans (GBToxCe), Universidade Federal do Pampa, Uruguaiana, RS, 97500-970, Brazil.
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Pathak A, Chatterjee N, Sinha S. Developmental trajectory of Caenorhabditis elegans nervous system governs its structural organization. PLoS Comput Biol 2020; 16:e1007602. [PMID: 31895942 PMCID: PMC6959611 DOI: 10.1371/journal.pcbi.1007602] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Revised: 01/14/2020] [Accepted: 12/11/2019] [Indexed: 11/22/2022] Open
Abstract
A central problem of neuroscience involves uncovering the principles governing the organization of nervous systems which ensure robustness in brain development. The nematode Caenorhabditis elegans provides us with a model organism for studying this question. In this paper, we focus on the invariant connection structure and spatial arrangement of the neurons comprising the somatic neuronal network of this organism to understand the key developmental constraints underlying its design. We observe that neurons with certain shared characteristics-such as, neural process lengths, birth time cohort, lineage and bilateral symmetry-exhibit a preference for connecting to each other. Recognizing the existence of such homophily and their relative degree of importance in determining connection probability within neurons (for example, in synapses, symmetric pairing is the most dominant factor followed by birth time cohort, process length and lineage) helps in connecting specific neuronal attributes to the topological organization of the network. Further, the functional identities of neurons appear to dictate the temporal hierarchy of their appearance during the course of development. Providing crucial insights into principles that may be common across many organisms, our study shows how the trajectory in the developmental landscape constrains the structural organization of a nervous system.
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Affiliation(s)
- Anand Pathak
- The Institute of Mathematical Sciences, CIT Campus, Taramani, Chennai, India
- Homi Bhabha National Institute, Anushaktinagar, Mumbai, India
| | | | - Sitabhra Sinha
- The Institute of Mathematical Sciences, CIT Campus, Taramani, Chennai, India
- Homi Bhabha National Institute, Anushaktinagar, Mumbai, India
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Beets I, Zhang G, Fenk LA, Chen C, Nelson GM, Félix MA, de Bono M. Natural Variation in a Dendritic Scaffold Protein Remodels Experience-Dependent Plasticity by Altering Neuropeptide Expression. Neuron 2019; 105:106-121.e10. [PMID: 31757604 PMCID: PMC6953435 DOI: 10.1016/j.neuron.2019.10.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Revised: 08/18/2019] [Accepted: 09/28/2019] [Indexed: 12/13/2022]
Abstract
The extent to which behavior is shaped by experience varies between individuals. Genetic differences contribute to this variation, but the neural mechanisms are not understood. Here, we dissect natural variation in the behavioral flexibility of two Caenorhabditis elegans wild strains. In one strain, a memory of exposure to 21% O2 suppresses CO2-evoked locomotory arousal; in the other, CO2 evokes arousal regardless of previous O2 experience. We map that variation to a polymorphic dendritic scaffold protein, ARCP-1, expressed in sensory neurons. ARCP-1 binds the Ca2+-dependent phosphodiesterase PDE-1 and co-localizes PDE-1 with molecular sensors for CO2 at dendritic ends. Reducing ARCP-1 or PDE-1 activity promotes CO2 escape by altering neuropeptide expression in the BAG CO2 sensors. Variation in ARCP-1 alters behavioral plasticity in multiple paradigms. Our findings are reminiscent of genetic accommodation, an evolutionary process by which phenotypic flexibility in response to environmental variation is reset by genetic change. Behavioral flexibility varies across Caenorhabditis and C. elegans wild isolates A natural polymorphism in ARCP-1 underpins inter-individual variation in plasticity ARCP-1 is a dendritic scaffold protein localizing cGMP signaling machinery to cilia Disrupting ARCP-1 alters behavioral plasticity by changing neuropeptide expression
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Affiliation(s)
- Isabel Beets
- Cell Biology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Gaotian Zhang
- Institut de Biologie de l'École Normale Supérieure, CNRS, Inserm, PSL Research University, Paris 75005, France
| | - Lorenz A Fenk
- Cell Biology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Changchun Chen
- Cell Biology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Geoffrey M Nelson
- Cell Biology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Marie-Anne Félix
- Institut de Biologie de l'École Normale Supérieure, CNRS, Inserm, PSL Research University, Paris 75005, France.
| | - Mario de Bono
- Cell Biology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK.
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Romero-Afrima L, Zelmanovich V, Abergel Z, Zuckerman B, Shaked M, Abergel R, Livshits L, Smith Y, Gross E. Ferritin is regulated by a neuro-intestinal axis in the nematode Caenorhabditis elegans. Redox Biol 2019; 28:101359. [PMID: 31677552 PMCID: PMC6920132 DOI: 10.1016/j.redox.2019.101359] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 10/17/2019] [Accepted: 10/21/2019] [Indexed: 01/24/2023] Open
Abstract
Iron is vital for the life of most organisms. However, when dysregulated, iron can catalyze the formation of oxygen (O2) radicals that can destroy any biological molecule and thus lead to oxidative injury and death. Therefore, iron metabolism must be tightly regulated at all times, as well as coordinated with the metabolism of O2. However, how is this achieved at the whole animal level is not well understood. Here, we explore this question using the nematode Caenorhabditis elegans. Exposure of worms to O2 starvation conditions (i.e. hypoxia) induces a major upregulation in levels of the conserved iron-cage protein ferritin 1 (ftn-1) in the intestine, while exposure to 21% O2 decreases ftn-1 level. This O2-dependent inhibition is mediated by O2-sensing neurons that communicate with the intestine through neurotransmitter and neuropeptide signalling, and requires the activity of hydroxylated HIF-1. By contrast, the induction of ftn-1 in hypoxia appears to be HIF-1-independent. This upregulation provides protection against Pseudomonas aeruginosa bacteria and oxidative injury. Taken together, our studies uncover a neuro-intestine axis that coordinates O2 and iron responses at the whole animal level. The expression of ferritin 1 (ftn-1) is tightly regulated by O2 tension. O2-sensing neurons inhibit the expression of ftn-1 in the intestine at 21% O2. Hydroxylated–HIF–1 inhibits the expression of ftn-1 at 21% O2. ftn-1 is important for protecting against Pseudomonas aeruginosa bacteria.
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Affiliation(s)
- Leonor Romero-Afrima
- Dept. of Biochemistry and Molecular Biology, IMRIC, Faculty of Medicine, The Hebrew University of Jerusalem, Ein Kerem. P.O. Box 12271, Jerusalem, 9112102, Israel
| | - Veronica Zelmanovich
- Dept. of Biochemistry and Molecular Biology, IMRIC, Faculty of Medicine, The Hebrew University of Jerusalem, Ein Kerem. P.O. Box 12271, Jerusalem, 9112102, Israel
| | - Zohar Abergel
- Dept. of Biochemistry and Molecular Biology, IMRIC, Faculty of Medicine, The Hebrew University of Jerusalem, Ein Kerem. P.O. Box 12271, Jerusalem, 9112102, Israel
| | - Binyamin Zuckerman
- Dept. of Biochemistry and Molecular Biology, IMRIC, Faculty of Medicine, The Hebrew University of Jerusalem, Ein Kerem. P.O. Box 12271, Jerusalem, 9112102, Israel
| | - Maayan Shaked
- Dept. of Biochemistry and Molecular Biology, IMRIC, Faculty of Medicine, The Hebrew University of Jerusalem, Ein Kerem. P.O. Box 12271, Jerusalem, 9112102, Israel
| | - Rachel Abergel
- Dept. of Biochemistry and Molecular Biology, IMRIC, Faculty of Medicine, The Hebrew University of Jerusalem, Ein Kerem. P.O. Box 12271, Jerusalem, 9112102, Israel
| | - Leonid Livshits
- Dept. of Biochemistry and Molecular Biology, IMRIC, Faculty of Medicine, The Hebrew University of Jerusalem, Ein Kerem. P.O. Box 12271, Jerusalem, 9112102, Israel
| | - Yoav Smith
- Genomic Data Analysis Unit, The Hebrew University - Hadassah Medical School, The Hebrew University of Jerusalem, 91120, Jerusalem, Israel
| | - Einav Gross
- Dept. of Biochemistry and Molecular Biology, IMRIC, Faculty of Medicine, The Hebrew University of Jerusalem, Ein Kerem. P.O. Box 12271, Jerusalem, 9112102, Israel.
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Abstract
Carbon dioxide (CO2) is an important sensory cue for many animals, including both parasitic and free-living nematodes. Many nematodes show context-dependent, experience-dependent and/or life-stage-dependent behavioural responses to CO2, suggesting that CO2 plays crucial roles throughout the nematode life cycle in multiple ethological contexts. Nematodes also show a wide range of physiological responses to CO2. Here, we review the diverse responses of parasitic and free-living nematodes to CO2. We also discuss the molecular, cellular and neural circuit mechanisms that mediate CO2 detection in nematodes, and that drive context-dependent and experience-dependent responses of nematodes to CO2.
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How Caenorhabditis elegans Senses Mechanical Stress, Temperature, and Other Physical Stimuli. Genetics 2019; 212:25-51. [PMID: 31053616 PMCID: PMC6499529 DOI: 10.1534/genetics.118.300241] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 03/04/2019] [Indexed: 12/30/2022] Open
Abstract
Caenorhabditis elegans lives in a complex habitat in which they routinely experience large fluctuations in temperature, and encounter physical obstacles that vary in size and composition. Their habitat is shared by other nematodes, by beneficial and harmful bacteria, and nematode-trapping fungi. Not surprisingly, these nematodes can detect and discriminate among diverse environmental cues, and exhibit sensory-evoked behaviors that are readily quantifiable in the laboratory at high resolution. Their ability to perform these behaviors depends on <100 sensory neurons, and this compact sensory nervous system together with powerful molecular genetic tools has allowed individual neuron types to be linked to specific sensory responses. Here, we describe the sensory neurons and molecules that enable C. elegans to sense and respond to physical stimuli. We focus primarily on the pathways that allow sensation of mechanical and thermal stimuli, and briefly consider this animal’s ability to sense magnetic and electrical fields, light, and relative humidity. As the study of sensory transduction is critically dependent upon the techniques for stimulus delivery, we also include a section on appropriate laboratory methods for such studies. This chapter summarizes current knowledge about the sensitivity and response dynamics of individual classes of C. elegans mechano- and thermosensory neurons from in vivo calcium imaging and whole-cell patch-clamp electrophysiology studies. We also describe the roles of conserved molecules and signaling pathways in mediating the remarkably sensitive responses of these nematodes to mechanical and thermal cues. These studies have shown that the protein partners that form mechanotransduction channels are drawn from multiple superfamilies of ion channel proteins, and that signal transduction pathways responsible for temperature sensing in C. elegans share many features with those responsible for phototransduction in vertebrates.
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Meneely PM, Dahlberg CL, Rose JK. Working with Worms:Caenorhabditis elegansas a Model Organism. ACTA ACUST UNITED AC 2019. [DOI: 10.1002/cpet.35] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
| | | | - Jacqueline K. Rose
- Behavioral Neuroscience Program, Department of PsychologyWestern Washington University Bellingham Washington
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Sinnige T, Ciryam P, Casford S, Dobson CM, de Bono M, Vendruscolo M. Expression of the amyloid-β peptide in a single pair of C. elegans sensory neurons modulates the associated behavioural response. PLoS One 2019; 14:e0217746. [PMID: 31150491 PMCID: PMC6544271 DOI: 10.1371/journal.pone.0217746] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 05/19/2019] [Indexed: 12/21/2022] Open
Abstract
Although the aggregation of the amyloid-β peptide (Aβ) into amyloid fibrils is a well-established hallmark of Alzheimer’s disease, the complex mechanisms linking this process to neurodegeneration are still incompletely understood. The nematode worm C. elegans is a valuable model organism through which to study these mechanisms because of its simple nervous system and its relatively short lifespan. Standard Aβ-based C. elegans models of Alzheimer’s disease are designed to study the toxic effects of the overexpression of Aβ in the muscle or nervous systems. However, the wide variety of effects associated with the tissue-level overexpression of Aβ makes it difficult to single out and study specific cellular mechanisms related to the onset of Alzheimer’s disease. Here, to better understand how to investigate the early events affecting neuronal signalling, we created a C. elegans model expressing Aβ42, the 42-residue form of Aβ, from a single-copy gene insertion in just one pair of glutamatergic sensory neurons, the BAG neurons. In behavioural assays, we found that the Aβ42-expressing animals displayed a subtle modulation of the response to CO2, compared to controls. Ca2+ imaging revealed that the BAG neurons in young Aβ42-expressing nematodes were activated more strongly than in control animals, and that neuronal activation remained intact until old age. Taken together, our results suggest that Aβ42-expression in this very subtle model of AD is sufficient to modulate the behavioural response but not strong enough to generate significant neurotoxicity, suggesting that slightly more aggressive perturbations will enable effectively studies of the links between the modulation of a physiological response and its associated neurotoxicity.
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Affiliation(s)
- Tessa Sinnige
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Prashanth Ciryam
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Samuel Casford
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Christopher M. Dobson
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Mario de Bono
- Cell Biology Division, Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Michele Vendruscolo
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
- * E-mail:
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Koide T, Yabuki Y, Yoshihara Y. Terminal Nerve GnRH3 Neurons Mediate Slow Avoidance of Carbon Dioxide in Larval Zebrafish. Cell Rep 2019; 22:1115-1123. [PMID: 29386100 DOI: 10.1016/j.celrep.2018.01.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2017] [Revised: 12/01/2017] [Accepted: 01/05/2018] [Indexed: 12/13/2022] Open
Abstract
Escape responses to threatening stimuli are vital for survival in all animal species. Larval zebrafish display fast escape responses when exposed to tactile, acoustic, and visual stimuli. However, their behavioral responses to chemosensory stimuli remain unknown. In this study, we found that carbon dioxide (CO2) induced a slow avoidance response, which was distinct from the touch-evoked fast escape response. We identified the gonadotropin-releasing hormone 3-expressing terminal nerve as the CO2 sensor in the nose. Wide-field calcium imaging revealed downstream CO2-activated ensembles of neurons along three distinct neural pathways, olfactory, trigeminal, and habenulo-interpeduncular, further reaching the reticulospinal neurons in the hindbrain. Ablation of the nose, terminal nerve, or trigeminal ganglion resulted in a dramatic decrease in CO2-evoked avoidance responses. These findings demonstrate that the terminal nerve-trigeminal system plays a pivotal role in triggering a slow chemosensory avoidance behavior in the larval zebrafish.
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Affiliation(s)
- Tetsuya Koide
- Laboratory for Neurobiology of Synapse, RIKEN Brain Science Institute, Saitama 351-0198, Japan.
| | - Yoichi Yabuki
- Laboratory for Neurobiology of Synapse, RIKEN Brain Science Institute, Saitama 351-0198, Japan
| | - Yoshihiro Yoshihara
- Laboratory for Neurobiology of Synapse, RIKEN Brain Science Institute, Saitama 351-0198, Japan; RIKEN BSI-KAO Collaboration Center, RIKEN Brain Science Institute, Saitama 351-0198, Japan; ERATO Touhara Chemosensory Signal Project, JST, The University of Tokyo, Tokyo 113-8657, Japan.
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Hoffman C, Aballay A. Role of neurons in the control of immune defense. Curr Opin Immunol 2019; 60:30-36. [PMID: 31117013 DOI: 10.1016/j.coi.2019.04.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 04/11/2019] [Accepted: 04/12/2019] [Indexed: 11/28/2022]
Abstract
Studies in recent years have strengthened the notion that neural mechanisms are involved in the control of immune responses. From initial studies that highlighted the vagus nerve control of inflammatory responses in vertebrates, many advances have been made, including the dissection of specific neural circuits that are involved in controlling immunity. Part of this has been facilitated by the use of a tractable model animal, Caenorhabditis elegans, in which individual neurons involved in sensing pathogens and controlling the immune response have been identified. Importantly, some of the underlying mechanisms involved in the neural control of immune pathways appear to be present in evolutionarily diverse species. This review focuses on some major developments in vertebrates and C. elegans, and how these discoveries may lead to advances in understanding neural-immune connections that govern inflammatory responses.
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Affiliation(s)
- Casandra Hoffman
- Molecular Microbiology and Immunology, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, 6351 Richard Jones Hall, Mail Code: L220, Portland, OR 97239, United States
| | - Alejandro Aballay
- Molecular Microbiology and Immunology, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, 6351 Richard Jones Hall, Mail Code: L220, Portland, OR 97239, United States.
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Anderson A, McMullan R. Neuronal and non-neuronal signals regulate Caernorhabditis elegans avoidance of contaminated food. Philos Trans R Soc Lond B Biol Sci 2019; 373:rstb.2017.0255. [PMID: 29866922 PMCID: PMC6000145 DOI: 10.1098/rstb.2017.0255] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/06/2017] [Indexed: 01/24/2023] Open
Abstract
One way in which animals minimize the risk of infection is to reduce their contact with contaminated food. Here, we establish a model of pathogen-contaminated food avoidance using the nematode worm Caernorhabditis elegans. We find that avoidance of pathogen-contaminated food protects C. elegans from the deleterious effects of infection and, using genetic approaches, demonstrate that multiple sensory neurons are required for this avoidance behaviour. In addition, our results reveal that the avoidance of contaminated food requires bacterial adherence to non-neuronal cells in the tail of C. elegans that are also required for the cellular immune response. Previous studies in C. elegans have contributed significantly to our understanding of molecular and cellular basis of host–pathogen interactions and our model provides a unique opportunity to gain basic insights into how animals avoid contaminated food. This article is part of the Theo Murphy meeting issue ‘Evolution of pathogen and parasite avoidance behaviours’.
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Affiliation(s)
- Alexandra Anderson
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
| | - Rachel McMullan
- School of Life, Health and Chemical Sciences, The Open University, Milton Keynes, Buckinghamshire MK7 2AA, UK
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Singh J, Aballay A. Microbial Colonization Activates an Immune Fight-and-Flight Response via Neuroendocrine Signaling. Dev Cell 2019; 49:89-99.e4. [PMID: 30827896 DOI: 10.1016/j.devcel.2019.02.001] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 10/26/2018] [Accepted: 01/31/2019] [Indexed: 01/01/2023]
Abstract
The ability to distinguish harmful and beneficial microbes is critical for the survival of an organism. Here, we show that bloating of the intestinal lumen of Caenorhabditis elegans caused by microbial colonization elicits a microbial aversion behavior. Bloating of the intestinal lumen also activates a broad innate immune response, even in the absence of bacterial pathogens or live bacteria. Neuroendocrine pathway genes are upregulated by intestinal bloating and are required for microbial aversion behavior. We propose that microbial colonization and bloating of the intestine may be perceived as a danger signal that activates an immune fight-and-flight response. These results reveal how inputs from the intestine can aid in the recognition of a broad range of microbes and modulate host behavior via neuroendocrine signaling.
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Affiliation(s)
- Jogender Singh
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, OR 97239, USA
| | - Alejandro Aballay
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, OR 97239, USA.
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40
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Feeding state sculpts a circuit for sensory valence in Caenorhabditis elegans. Proc Natl Acad Sci U S A 2019; 116:1776-1781. [PMID: 30651312 DOI: 10.1073/pnas.1807454116] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Hunger affects the behavioral choices of all animals, and many chemosensory stimuli can be either attractive or repulsive depending on an animal's hunger state. Although hunger-induced behavioral changes are well documented, the molecular and cellular mechanisms by which hunger modulates neural circuit function to generate changes in chemosensory valence are poorly understood. Here, we use the CO2 response of the free-living nematode Caenorhabditis elegans to elucidate how hunger alters valence. We show that CO2 response valence shifts from aversion to attraction during starvation, a change that is mediated by two pairs of interneurons in the CO2 circuit, AIY and RIG. The transition from aversion to attraction is regulated by biogenic amine signaling. Dopamine promotes CO2 repulsion in well-fed animals, whereas octopamine promotes CO2 attraction in starved animals. Biogenic amines also regulate the temporal dynamics of the shift from aversion to attraction such that animals lacking octopamine show a delayed shift to attraction. Biogenic amine signaling regulates CO2 response valence by modulating the CO2-evoked activity of AIY and RIG. Our results illuminate a new role for biogenic amine signaling in regulating chemosensory valence as a function of hunger state.
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41
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Bryant AS, Hallem EA. Terror in the dirt: Sensory determinants of host seeking in soil-transmitted mammalian-parasitic nematodes. Int J Parasitol Drugs Drug Resist 2018; 8:496-510. [PMID: 30396862 PMCID: PMC6287541 DOI: 10.1016/j.ijpddr.2018.10.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 10/22/2018] [Accepted: 10/24/2018] [Indexed: 12/12/2022]
Abstract
Infection with gastrointestinal parasitic nematodes is a major cause of chronic morbidity and economic burden around the world, particularly in low-resource settings. Some parasitic nematode species, including the human-parasitic threadworm Strongyloides stercoralis and human-parasitic hookworms in the genera Ancylostoma and Necator, feature a soil-dwelling infective larval stage that seeks out hosts for infection using a variety of host-emitted sensory cues. Here, we review our current understanding of the behavioral responses of soil-dwelling infective larvae to host-emitted sensory cues, and the molecular and cellular mechanisms that mediate these responses. We also discuss the development of methods for transgenesis and CRISPR/Cas9-mediated targeted mutagenesis in Strongyloides stercoralis and the closely related rat parasite Strongyloides ratti. These methods have established S. stercoralis and S. ratti as genetic model systems for gastrointestinal parasitic nematodes and are enabling more detailed investigations into the neural mechanisms that underlie the sensory-driven behaviors of this medically and economically important class of parasites.
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Affiliation(s)
- Astra S Bryant
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, CA, 90095, USA
| | - Elissa A Hallem
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, CA, 90095, USA.
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42
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Oranth A, Schultheis C, Tolstenkov O, Erbguth K, Nagpal J, Hain D, Brauner M, Wabnig S, Steuer Costa W, McWhirter RD, Zels S, Palumbos S, Miller III DM, Beets I, Gottschalk A. Food Sensation Modulates Locomotion by Dopamine and Neuropeptide Signaling in a Distributed Neuronal Network. Neuron 2018; 100:1414-1428.e10. [DOI: 10.1016/j.neuron.2018.10.024] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 09/14/2018] [Accepted: 10/12/2018] [Indexed: 01/02/2023]
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43
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Khan F, Jain S, Oloketuyi SF. Bacteria and bacterial products: Foe and friends to Caenorhabditis elegans. Microbiol Res 2018; 215:102-113. [DOI: 10.1016/j.micres.2018.06.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 06/11/2018] [Accepted: 06/24/2018] [Indexed: 02/07/2023]
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44
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Metaxakis A, Petratou D, Tavernarakis N. Multimodal sensory processing in Caenorhabditis elegans. Open Biol 2018; 8:180049. [PMID: 29925633 PMCID: PMC6030117 DOI: 10.1098/rsob.180049] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 05/22/2018] [Indexed: 12/22/2022] Open
Abstract
Multisensory integration is a mechanism that allows organisms to simultaneously sense and understand external stimuli from different modalities. These distinct signals are transduced into neuronal signals that converge into decision-making neuronal entities. Such decision-making centres receive information through neuromodulators regarding the organism's physiological state and accordingly trigger behavioural responses. Despite the importance of multisensory integration for efficient functioning of the nervous system, and also the implication of dysfunctional multisensory integration in the aetiology of neuropsychiatric disease, little is known about the relative molecular mechanisms. Caenorhabditis elegans is an appropriate model system to study such mechanisms and elucidate the molecular ways through which organisms understand external environments in an accurate and coherent fashion.
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Affiliation(s)
- Athanasios Metaxakis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, Nikolaou Plastira 100, Heraklion 70013, Crete, Greece
| | - Dionysia Petratou
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, Nikolaou Plastira 100, Heraklion 70013, Crete, Greece
| | - Nektarios Tavernarakis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, Nikolaou Plastira 100, Heraklion 70013, Crete, Greece
- Department of Basic Sciences, Faculty of Medicine, University of Crete, Heraklion 71110, Crete, Greece
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45
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Yuan S, Sharma AK, Richart A, Lee J, Kim BE. CHCA-1 is a copper-regulated CTR1 homolog required for normal development, copper accumulation, and copper-sensing behavior in Caenorhabditis elegans. J Biol Chem 2018; 293:10911-10925. [PMID: 29784876 DOI: 10.1074/jbc.ra118.003503] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Indexed: 01/11/2023] Open
Abstract
Copper plays key roles in catalytic and regulatory biochemical reactions essential for normal growth, development, and health. Dietary copper deficiencies or mutations in copper homeostasis genes can lead to abnormal musculoskeletal development, cognitive disorders, and poor growth. In yeast and mammals, copper is acquired through the activities of the CTR1 family of high-affinity copper transporters. However, the mechanisms of systemic responses to dietary or tissue-specific copper deficiency remain unclear. Here, taking advantage of the animal model Caenorhabditis elegans for studying whole-body copper homeostasis, we investigated the role of a C. elegans CTR1 homolog, CHCA-1, in copper acquisition and in worm growth, development, and behavior. Using sequence homology searches, we identified 10 potential orthologs to mammalian CTR1 Among these genes, we found that chca-1, which is transcriptionally up-regulated in the intestine and hypodermis of C. elegans during copper deficiency, is required for normal growth, reproduction, and maintenance of systemic copper balance under copper deprivation. The intestinal copper transporter CUA-1 normally traffics to endosomes to sequester excess copper, and we found here that loss of chca-1 caused CUA-1 to mislocalize to the basolateral membrane under copper overload conditions. Moreover, animals lacking chca-1 exhibited significantly reduced copper avoidance behavior in response to toxic copper conditions compared with WT worms. These results establish that CHCA-1-mediated copper acquisition in C. elegans is crucial for normal growth, development, and copper-sensing behavior.
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Affiliation(s)
- Sai Yuan
- From the Department of Animal and Avian Sciences and
| | | | | | - Jaekwon Lee
- the Redox Biology Center, Department of Biochemistry, University of Nebraska, Lincoln, Nebraska 68588
| | - Byung-Eun Kim
- From the Department of Animal and Avian Sciences and .,Biological Sciences Graduate Program, University of Maryland, College Park, Maryland 20742 and
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46
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FLP-18 Functions through the G-Protein-Coupled Receptors NPR-1 and NPR-4 to Modulate Reversal Length in Caenorhabditis elegans. J Neurosci 2018; 38:4641-4654. [PMID: 29712787 PMCID: PMC5965667 DOI: 10.1523/jneurosci.1955-17.2018] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2017] [Revised: 03/27/2018] [Accepted: 03/31/2018] [Indexed: 01/03/2023] Open
Abstract
Animal behavior is critically dependent on the activity of neuropeptides. Reversals, one of the most conspicuous behaviors in Caenorhabditis elegans, plays an important role in determining the navigation strategy of the animal. Our experiments on hermaphrodite C. elegans show the involvement of a neuropeptide FLP-18 in modulating reversal length in these hermaphrodites. We show that FLP-18 controls the reversal length by regulating the activity of AVA interneurons through the G-protein-coupled neuropeptide receptors, NPR-4 and NPR-1. We go on to show that the site of action of these receptors is the AVA interneuron for NPR-4 and the ASE sensory neurons for NPR-1. We further show that mutants in the neuropeptide, flp-18, and its receptors show increased reversal lengths. Consistent with the behavioral data, calcium levels in the AVA neuron of freely reversing C. elegans were significantly higher and persisted for longer durations in flp-18, npr-1, npr-4, and npr-1 npr-4 genetic backgrounds compared with wild-type control animals. Finally, we show that increasing FLP-18 levels through genetic and physiological manipulations causes shorter reversal lengths. Together, our analysis suggests that the FLP-18/NPR-1/NPR-4 signaling is a pivotal point in the regulation of reversal length under varied genetic and environmental conditions. SIGNIFICANCE STATEMENT In this study, we elucidate the circuit and molecular machinery required for normal reversal behavior in hermaphrodite Caenorhabditis elegans. We delineate the circuit and the neuropeptide receptors required for maintaining reversal length in C. elegans. Our work sheds light on the importance of a single neuropeptide, FLP-18, and how change in levels in this one peptide could allow the animal to change the length of its reversal, thereby modulating how the C. elegans explores its environment. We also go on to show that FLP-18 functions to maintain reversal length through the neuropeptide receptors NPR-4 and NPR-1. Our study will allow for a better understanding of the complete repertoire of behaviors shown by freely moving animals as they explore their environment.
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Vidal-Gadea A, Bainbridge C, Clites B, Palacios BE, Bakhtiari L, Gordon V, Pierce-Shimomura J. Response to comment on "Magnetosensitive neurons mediate geomagnetic orientation in Caenorhabditis elegans". eLife 2018; 7:31414. [PMID: 29651982 PMCID: PMC5898907 DOI: 10.7554/elife.31414] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 03/19/2018] [Indexed: 01/26/2023] Open
Abstract
Many animals can orient using the earth’s magnetic field. In a recent study, we performed three distinct behavioral assays providing evidence that the nematode Caenorhabditis elegans orients to earth-strength magnetic fields (Vidal-Gadea et al., 2015). A new study by Landler et al. suggests that C. elegans does not orient to magnetic fields (Landler et al., 2018). They also raise conceptual issues that cast doubt on our study. Here, we explain how they appear to have missed positive results in part by omitting controls and running assays longer than prescribed, so that worms switched their preferred migratory direction within single tests. We also highlight differences in experimental methods and interpretations that may explain our different results and conclusions. Together, these findings provide guidance on how to achieve robust magnetotaxis and reinforce our original finding that C. elegans is a suitable model system to study magnetoreception.
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Affiliation(s)
- Andres Vidal-Gadea
- School of Biological Sciences, Illinois State University, Normal, United States
| | - Chance Bainbridge
- School of Biological Sciences, Illinois State University, Normal, United States
| | - Ben Clites
- Department of Physics, University of Texas at Austin, Austin, United States
| | - Bridgitte E Palacios
- Department of Physics, University of Texas at Austin, Austin, United States.,Department of Neuroscience, University of Texas at Austin, Austin, United States
| | - Layla Bakhtiari
- Department of Neuroscience, University of Texas at Austin, Austin, United States
| | - Vernita Gordon
- Department of Neuroscience, University of Texas at Austin, Austin, United States
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48
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Rojo Romanos T, Ng L, Pocock R. Behavioral Assays to Study Oxygen and Carbon Dioxide Sensing in Caenorhabditis elegans. Bio Protoc 2018; 8:e2679. [PMID: 29335676 DOI: 10.21769/bioprotoc.2679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
Abstract
Animals use behavioral strategies to seek optimal environments. Population behavioral assays provide a robust means to determine the effect of genetic perturbations on the ability of animals to sense and respond to changes in the environment. Here, we describe a C. elegans population behavioral assay used to measure locomotory responses to changes in environmental oxygen (O2) and carbon dioxide (CO2) concentrations. These behavioral assays are high-throughput and enable examination of genetic, neuronal and circuit function.
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Affiliation(s)
- Teresa Rojo Romanos
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, Victoria, Australia.,Biotech Research and Innovation Centre, University of Copenhagen, Copenhagen, Denmark
| | - Leelee Ng
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, Victoria, Australia
| | - Roger Pocock
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, Victoria, Australia.,Biotech Research and Innovation Centre, University of Copenhagen, Copenhagen, Denmark
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49
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Thapliyal S, Babu K. C. elegans Locomotion: Finding Balance in Imbalance. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1112:185-196. [PMID: 30637699 DOI: 10.1007/978-981-13-3065-0_14] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The excitation-inhibition (E-I) imbalance in neural circuits represents a hallmark of several neuropsychiatric disorders. The tiny nematode Caenorhabditis elegans has emerged as an excellent system to study the molecular mechanisms underlying this imbalance in neuronal circuits. The C. elegans body wall muscles receive inputs from both excitatory cholinergic and inhibitory GABAergic motor neurons at neuromuscular junctions (NMJ), making it an excellent model for studying the genetic and molecular mechanisms required for maintaining E-I balance at the NMJ. The cholinergic neurons form dyadic synapses wherein they synapse onto ipsilateral body wall muscles allowing for muscle contraction as well as onto GABAergic motor neurons that in turn synapse on the contralateral body wall muscles causing muscle relaxation. An alternating wave of contraction and relaxation mediated by excitatory and inhibitory signals maintains locomotion in C. elegans. This locomotory behavior requires an intricate balance between the excitatory cholinergic signaling and the inhibitory GABAergic signaling mechanisms.Studies on the C. elegans NMJ have provided insights into several molecular mechanisms that could regulate this balance in neural circuits. This review provides a discussion on multiple genetic factors including neuropeptides and their receptors, cell adhesion molecules, and other molecular pathways that have been associated with maintaining E-I balance in C. elegans motor circuits. Further, it also discusses the implications of these studies that could help us in understanding the role of E-I balance in mammalian neural circuits and how changes in this balance could give rise to brain disorders.
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Affiliation(s)
- Shruti Thapliyal
- Indian Institute of Science Education and Research (IISER), Mohali, Punjab, India.
| | - Kavita Babu
- Indian Institute of Science Education and Research (IISER), Mohali, Punjab, India.
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50
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Grove C, Cain S, Chen WJ, Davis P, Harris T, Howe KL, Kishore R, Lee R, Paulini M, Raciti D, Tuli MA, Van Auken K, Williams G. Using WormBase: A Genome Biology Resource for Caenorhabditis elegans and Related Nematodes. Methods Mol Biol 2018; 1757:399-470. [PMID: 29761466 DOI: 10.1007/978-1-4939-7737-6_14] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
WormBase ( www.wormbase.org ) provides the nematode research community with a centralized database for information pertaining to nematode genes and genomes. As more nematode genome sequences are becoming available and as richer data sets are published, WormBase strives to maintain updated information, displays, and services to facilitate efficient access to and understanding of the knowledge generated by the published nematode genetics literature. This chapter aims to provide an explanation of how to use basic features of WormBase, new features, and some commonly used tools and data queries. Explanations of the curated data and step-by-step instructions of how to access the data via the WormBase website and available data mining tools are provided.
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Affiliation(s)
- Christian Grove
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA.
| | - Scott Cain
- Informatics and Bio-computing Platform, Ontario Institute for Cancer Research, Toronto, ON, Canada
| | - Wen J Chen
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Paul Davis
- European Molecular Biology Laboratory, European Bioinformatics Institute, Cambridge, UK
| | - Todd Harris
- Informatics and Bio-computing Platform, Ontario Institute for Cancer Research, Toronto, ON, Canada
| | - Kevin L Howe
- European Molecular Biology Laboratory, European Bioinformatics Institute, Cambridge, UK
| | - Ranjana Kishore
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Raymond Lee
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Michael Paulini
- European Molecular Biology Laboratory, European Bioinformatics Institute, Cambridge, UK
| | - Daniela Raciti
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Mary Ann Tuli
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Kimberly Van Auken
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Gary Williams
- European Molecular Biology Laboratory, European Bioinformatics Institute, Cambridge, UK
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