1
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Leung NY, Xu C, Li JSS, Ganguly A, Meyerhof GT, Regimbald-Dumas Y, Lane EA, Breault DT, He X, Perrimon N, Montell C. Gut tumors in flies alter the taste valence of an anti-tumorigenic bitter compound. Curr Biol 2024; 34:2623-2632.e5. [PMID: 38823383 DOI: 10.1016/j.cub.2024.04.082] [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: 08/25/2022] [Revised: 03/28/2024] [Accepted: 04/30/2024] [Indexed: 06/03/2024]
Abstract
The sense of taste is essential for survival, as it allows animals to distinguish between foods that are nutritious from those that are toxic. However, innate responses to different tastants can be modulated or even reversed under pathological conditions. Here, we examined whether and how the internal status of an animal impacts taste valence by using Drosophila models of hyperproliferation in the gut. In all three models where we expressed proliferation-inducing transgenes in intestinal stem cells (ISCs), hyperproliferation of ISCs caused a tumor-like phenotype in the gut. While tumor-bearing flies had no deficiency in overall food intake, strikingly, they exhibited an increased gustatory preference for aristolochic acid (ARI), which is a bitter and normally aversive plant-derived chemical. ARI had anti-tumor effects in all three of our gut hyperproliferation models. For other aversive chemicals we tested that are bitter but do not have anti-tumor effects, gut tumors did not affect avoidance behaviors. We demonstrated that bitter-sensing gustatory receptor neurons (GRNs) in tumor-bearing flies respond normally to ARI. Therefore, the internal pathology of gut hyperproliferation affects neural circuits that determine taste valence postsynaptic to GRNs rather than altering taste identity by GRNs. Overall, our data suggest that increased consumption of ARI may represent an attempt at self-medication. Finally, although ARI's potential use as a chemotherapeutic agent is limited by its known toxicity in the liver and kidney, our findings suggest that tumor-bearing flies might be a useful animal model to screen for novel anti-tumor drugs.
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Affiliation(s)
- Nicole Y Leung
- Neuroscience Research Institute, University of California, Santa Barbara, CA 93106, USA; Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, CA 93106, USA
| | - Chiwei Xu
- Department of Genetics, Blavatnik Institute, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115, USA.
| | - Joshua Shing Shun Li
- Department of Genetics, Blavatnik Institute, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115, USA
| | - Anindya Ganguly
- Neuroscience Research Institute, University of California, Santa Barbara, CA 93106, USA; Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, CA 93106, USA
| | - Geoff T Meyerhof
- Neuroscience Research Institute, University of California, Santa Barbara, CA 93106, USA; Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, CA 93106, USA
| | - Yannik Regimbald-Dumas
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Elizabeth A Lane
- Department of Genetics, Blavatnik Institute, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115, USA
| | - David T Breault
- Division of Endocrinology, Boston Children's Hospital, Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
| | - Xi He
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Norbert Perrimon
- Department of Genetics, Blavatnik Institute, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115, USA; Howard Hughes Medical Institute, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115, USA.
| | - Craig Montell
- Neuroscience Research Institute, University of California, Santa Barbara, CA 93106, USA; Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, CA 93106, USA.
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2
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Waris MI, Lei Y, Qi G, Guan Z, Rashied A, Chen J, Lyu L. The temporal-spatial expression and functional analysis of three gustatory receptor genes in Solenopsis invicta using sweet and bitter compounds. INSECT SCIENCE 2024; 31:448-468. [PMID: 38010036 DOI: 10.1111/1744-7917.13301] [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: 06/27/2023] [Revised: 10/07/2023] [Accepted: 10/16/2023] [Indexed: 11/29/2023]
Abstract
The insect gustatory system participates in identifying potential food sources and avoiding toxic compounds. During this process, gustatory receptors (GRs) recognize feeding stimulant and deterrent compounds. However, the GRs involved in recognizing stimulant and deterrent compounds in the red imported fire ant, Solenopsis invicta, remain unknown. Therefore, we conducted a study on the genes SinvGR1, SinvGR32b, and SinvGR28a to investigate the roles of GRs in detecting feeding stimulant and deterrent compounds. In this current study, we found that sucrose and fructose are feeding stimulants and the bitter compound quinine is a feeding deterrent. The fire ant workers showed significant behavior changes to avoid the bitter taste in feeding stimulant compounds. Reverse transcription quantitative real-time polymerase chain reaction results from developmental stages showed that the SinvGR1, SinvGR32b, and SinvGR28a genes were highly expressed in fire ant workers. Tissue-specific expression profiles indicated that SinvGR1, SinvGR32b, and SinvGR28a were specifically expressed in the antennae and foreleg tarsi of workers, whereas SinvGR32b gene transcripts were also highly accumulated in the male antennae. Furthermore, the silencing of SinvGR1 or SinvGR32b alone and the co-silencing of both genes disrupted worker stimulation and feeding on sucrose and fructose. The results also showed that SinvGR28a is required for avoiding quinine, as workers with knockdown of the SinvGR28a gene failed to avoid and fed on quinine. This study first identified stimulant and deterrent compounds of fire ant workers and then the GRs involved in the taste recognition of these compounds. This study could provide potential target gustatory genes for the control of the fire ant.
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Affiliation(s)
- Muhammad Irfan Waris
- Institute of Plant Protection, Guangdong Academy of Agricultural Sciences, Guangdong Provincial Key Laboratory of High Technology for Plant Protection, Guangzhou, China
| | - Yanyuan Lei
- Institute of Plant Protection, Guangdong Academy of Agricultural Sciences, Guangdong Provincial Key Laboratory of High Technology for Plant Protection, Guangzhou, China
| | - Guojun Qi
- Institute of Plant Protection, Guangdong Academy of Agricultural Sciences, Guangdong Provincial Key Laboratory of High Technology for Plant Protection, Guangzhou, China
| | - Ziying Guan
- Institute of Plant Protection, Guangdong Academy of Agricultural Sciences, Guangdong Provincial Key Laboratory of High Technology for Plant Protection, Guangzhou, China
| | - Abdul Rashied
- Institute of Plant Protection, Guangdong Academy of Agricultural Sciences, Guangdong Provincial Key Laboratory of High Technology for Plant Protection, Guangzhou, China
- Department of Entomology, College of Plant Protection, South China Agricultural University, Guangzhou, China
| | - Jie Chen
- Institute of Plant Protection, Guangdong Academy of Agricultural Sciences, Guangdong Provincial Key Laboratory of High Technology for Plant Protection, Guangzhou, China
| | - Lihua Lyu
- Institute of Plant Protection, Guangdong Academy of Agricultural Sciences, Guangdong Provincial Key Laboratory of High Technology for Plant Protection, Guangzhou, China
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3
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Deere JU, Sarkissian AA, Yang M, Uttley HA, Martinez Santana N, Nguyen L, Ravi K, Devineni AV. Selective integration of diverse taste inputs within a single taste modality. eLife 2023; 12:84856. [PMID: 36692370 PMCID: PMC9873257 DOI: 10.7554/elife.84856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Accepted: 01/10/2023] [Indexed: 01/25/2023] Open
Abstract
A fundamental question in sensory processing is how different channels of sensory input are processed to regulate behavior. Different input channels may converge onto common downstream pathways to drive the same behaviors, or they may activate separate pathways to regulate distinct behaviors. We investigated this question in the Drosophila bitter taste system, which contains diverse bitter-sensing cells residing in different taste organs. First, we optogenetically activated subsets of bitter neurons within each organ. These subsets elicited broad and highly overlapping behavioral effects, suggesting that they converge onto common downstream pathways, but we also observed behavioral differences that argue for biased convergence. Consistent with these results, transsynaptic tracing revealed that bitter neurons in different organs connect to overlapping downstream pathways with biased connectivity. We investigated taste processing in one type of downstream bitter neuron that projects to the higher brain. These neurons integrate input from multiple organs and regulate specific taste-related behaviors. We then traced downstream circuits, providing the first glimpse into taste processing in the higher brain. Together, these results reveal that different bitter inputs are selectively integrated early in the circuit, enabling the pooling of information, while the circuit then diverges into multiple pathways that may have different roles.
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Affiliation(s)
- Julia U Deere
- Zuckerman Mind Brain Behavior Institute, Columbia UniversityNew YorkUnited States
| | | | - Meifeng Yang
- Department of Biology, Emory UniversityAtlantaUnited States
| | - Hannah A Uttley
- Zuckerman Mind Brain Behavior Institute, Columbia UniversityNew YorkUnited States
| | | | - Lam Nguyen
- Department of Biology, Emory UniversityAtlantaUnited States
| | - Kaushiki Ravi
- Department of Biology, Emory UniversityAtlantaUnited States
| | - Anita V Devineni
- Zuckerman Mind Brain Behavior Institute, Columbia UniversityNew YorkUnited States
- Neuroscience Graduate Program, Emory UniversityAtlantaUnited States
- Department of Biology, Emory UniversityAtlantaUnited States
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4
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Zhao Y, Duan J, Han Z, Engström Y, Hartenstein V. Identification of a GABAergic neuroblast lineage modulating sweet and bitter taste sensitivity. Curr Biol 2022; 32:5354-5363.e3. [PMID: 36347251 PMCID: PMC10728805 DOI: 10.1016/j.cub.2022.10.029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 06/16/2022] [Accepted: 10/14/2022] [Indexed: 11/09/2022]
Abstract
In Drosophila melanogaster, processing of gustatory information and controlling feeding behavior are executed by neural circuits located in the subesophageal zone (SEZ) of the brain.1 Gustatory receptor neurons (GRNs) project their axons in the primary gustatory center (PGC), which is located in the SEZ.1,2,3,4 To address the function of the PGC, we need detailed information about the different classes of gustatory interneurons that frame the PGC. In this work, we screened large collections of driver lines for SEZ interneuron-specific labeling and subsequently used candidate lines to access the SEZ neuroblast lineages. We converted 130 Gal4 lines to LexA drivers and carried out functional screening using calcium imaging. We found one neuroblast lineage, TRdm, whose neurons responded to both sweet and bitter tastants, and formed green fluorescent protein (GFP) reconstitution across synaptic partners (GRASP)-positive synapses with sweet sensory neurons. TRdm neurons express the inhibitory transmitter GABA, and silencing these neurons increases appetitive feeding behavior. These results demonstrate that TRdm generates a class of inhibitory local neurons that control taste sensitivity in Drosophila.
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Affiliation(s)
- Yunpo Zhao
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden; Biozentrum, University of Basel, 4056 Basel, Switzerland; Center for Precision Disease Modeling, University of Maryland School of Medicine, Baltimore 21201, USA.
| | - Jianli Duan
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden; Center for Precision Disease Modeling, University of Maryland School of Medicine, Baltimore 21201, USA
| | - Zhe Han
- Center for Precision Disease Modeling, University of Maryland School of Medicine, Baltimore 21201, USA
| | - Ylva Engström
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden
| | - Volker Hartenstein
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles 90095-1606, USA.
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5
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Zhang G, Cao S, Guo T, Wang H, Qi X, Ren X, Niu C. Identification and expression profiles of gustatory receptor genes in Bactrocera minax larvae (Diptera: Tephritidae): Role of BminGR59f in larval growth. INSECT SCIENCE 2022; 29:1240-1250. [PMID: 35146929 DOI: 10.1111/1744-7917.13014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 01/03/2022] [Accepted: 01/26/2022] [Indexed: 06/14/2023]
Abstract
Insects employ various types of gustatory receptors (GRs) to identify nutrient-rich food and avoid toxic substances. The larval gustatory system is the critical checkpoint for food acceptance or rejection. As a specialist herbivore, the larvae of Bactrocera minax feed only on unripe citrus fruits. However, how larvae use GRs to check and adapt to the secondary metabolites in unripe citrus fruits remains unknown. In this study, we first performed developmental expression profiles showing that most BminGRs genes were highly expressed in 1st and 2nd instar larvae and that tissue-specific expression indicated high expression of most BminGRs genes in the mouthparts of 2nd instar larvae. Furthermore, we found that silencing BminGR59f by RNA interference (RNAi) affected the growth of 2nd instar B. minax larvae. Hesperidin and naringin were screened as ligands of BminGR59f via RNAi and cell calcium imaging, and the combination of these two flavones increased the body weight of larvae. In summary, we identified a novel gustatory perception pattern in B. minax for detecting hesperidin and naringin, which boosted the growth of B. minax larvae. These results shed light on how specialist herbivores detect and adapt to host metabolites in adverse environments depending on larval GRs.
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Affiliation(s)
- Guijian Zhang
- Hubei Key Laboratory of Insect Resource Application and Sustainable Pest Control, College of Plant Science & Technology, Huazhong Agricultural University, Wuhan, China
| | - Shuai Cao
- Hubei Key Laboratory of Insect Resource Application and Sustainable Pest Control, College of Plant Science & Technology, Huazhong Agricultural University, Wuhan, China
| | - Tong Guo
- Hubei Key Laboratory of Insect Resource Application and Sustainable Pest Control, College of Plant Science & Technology, Huazhong Agricultural University, Wuhan, China
| | - Haoran Wang
- Hubei Key Laboratory of Insect Resource Application and Sustainable Pest Control, College of Plant Science & Technology, Huazhong Agricultural University, Wuhan, China
| | - Xuewei Qi
- Hubei Key Laboratory of Insect Resource Application and Sustainable Pest Control, College of Plant Science & Technology, Huazhong Agricultural University, Wuhan, China
| | - Xueming Ren
- Hubei Key Laboratory of Insect Resource Application and Sustainable Pest Control, College of Plant Science & Technology, Huazhong Agricultural University, Wuhan, China
| | - Changying Niu
- Hubei Key Laboratory of Insect Resource Application and Sustainable Pest Control, College of Plant Science & Technology, Huazhong Agricultural University, Wuhan, China
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6
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Snell NJ, Fisher JD, Hartmann GG, Zolyomi B, Talay M, Barnea G. Complex representation of taste quality by second-order gustatory neurons in Drosophila. Curr Biol 2022; 32:3758-3772.e4. [PMID: 35973432 PMCID: PMC9474709 DOI: 10.1016/j.cub.2022.07.048] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 04/08/2022] [Accepted: 07/19/2022] [Indexed: 01/24/2023]
Abstract
Sweet and bitter compounds excite different sensory cells and drive opposing behaviors. However, it remains unclear how sweet and bitter tastes are represented by the neural circuits linking sensation to behavior. To investigate this question in Drosophila, we devised trans-Tango(activity), a strategy for calcium imaging of second-order gustatory projection neurons based on trans-Tango, a genetic transsynaptic tracing technique. We found spatial overlap between the projection neuron populations activated by sweet and bitter tastants. The spatial representation of bitter tastants in the projection neurons was consistent, while that of sweet tastants was heterogeneous. Furthermore, we discovered that bitter tastants evoke responses in the gustatory receptor neurons and projection neurons upon both stimulus onset and offset and that bitter offset and sweet onset excite overlapping second-order projections. These findings demonstrate an unexpected complexity in the representation of sweet and bitter tastants by second-order neurons of the gustatory circuit.
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Affiliation(s)
- Nathaniel J Snell
- Department of Neuroscience, Division of Biology and Medicine, Brown University, Providence, RI 02912, USA; The Robert J. and Nancy D. Carney Institute for Brain Science, Brown University, Providence, RI 02912, USA
| | - John D Fisher
- Department of Neuroscience, Division of Biology and Medicine, Brown University, Providence, RI 02912, USA; The Robert J. and Nancy D. Carney Institute for Brain Science, Brown University, Providence, RI 02912, USA
| | - Griffin G Hartmann
- Department of Neuroscience, Division of Biology and Medicine, Brown University, Providence, RI 02912, USA; The Robert J. and Nancy D. Carney Institute for Brain Science, Brown University, Providence, RI 02912, USA
| | - Bence Zolyomi
- Department of Neuroscience, Division of Biology and Medicine, Brown University, Providence, RI 02912, USA; The Robert J. and Nancy D. Carney Institute for Brain Science, Brown University, Providence, RI 02912, USA
| | - Mustafa Talay
- Department of Neuroscience, Division of Biology and Medicine, Brown University, Providence, RI 02912, USA; The Robert J. and Nancy D. Carney Institute for Brain Science, Brown University, Providence, RI 02912, USA
| | - Gilad Barnea
- Department of Neuroscience, Division of Biology and Medicine, Brown University, Providence, RI 02912, USA; The Robert J. and Nancy D. Carney Institute for Brain Science, Brown University, Providence, RI 02912, USA.
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7
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Sun LL, Liu XL, Wang YN, Berg BG, Xie GY, Chen WB, Liu Y, Wang GR, Zhao XC, Tang QB. Neuronal architecture and functional mapping of the taste center of larval Helicoverpa armigera (Lepidoptera: Noctuidae). INSECT SCIENCE 2022; 29:730-748. [PMID: 34427391 DOI: 10.1111/1744-7917.12965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 08/17/2021] [Accepted: 08/19/2021] [Indexed: 06/13/2023]
Abstract
The sense of taste plays a crucial role in herbivorous insects by discriminating nutrients from complex plant metabolic compounds. The peripheral coding of taste has been thoroughly studied in many insect species, but the central gustatory pathways are poorly described. In the present study, we characterized single neurons in the gnathal ganglion of Helicoverpa armigera larvae using the intracellular recording/staining technique. We identified different types of neurons, including sensory neurons, interneurons, and motor neurons. The morphologies of these neurons were largely diverse and their arborizations seemingly covered the whole gnathal ganglion. The representation of the single neurons responding to the relevant stimuli of sweet and bitter cues showed no distinct patterns in the gnathal ganglion. We postulate that taste signals may be processed in a manner consistent with the principle of population coding in the gnathal ganglion of H. armigera larvae.
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Affiliation(s)
- Long-Long Sun
- Department of Entomology, College of Plant Protection, Henan Agricultural University, Zhengzhou, 450002, China
| | - Xiao-Lan Liu
- Department of Entomology, College of Plant Protection, Henan Agricultural University, Zhengzhou, 450002, China
| | - Ya-Nan Wang
- Department of Entomology, College of Plant Protection, Henan Agricultural University, Zhengzhou, 450002, China
| | - Bente G Berg
- Chemosensory laboratory, Department of Psychology, Norwegian University of Science and Technology, Trondheim, 7489, Norway
| | - Gui-Ying Xie
- Department of Entomology, College of Plant Protection, Henan Agricultural University, Zhengzhou, 450002, China
| | - Wen-Bo Chen
- Department of Entomology, College of Plant Protection, Henan Agricultural University, Zhengzhou, 450002, China
| | - Yang Liu
- State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Gui-Rong Wang
- State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Xin-Cheng Zhao
- Department of Entomology, College of Plant Protection, Henan Agricultural University, Zhengzhou, 450002, China
| | - Qing-Bo Tang
- Department of Entomology, College of Plant Protection, Henan Agricultural University, Zhengzhou, 450002, China
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8
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Sareen PF, McCurdy LY, Nitabach MN. A neuronal ensemble encoding adaptive choice during sensory conflict in Drosophila. Nat Commun 2021; 12:4131. [PMID: 34226544 PMCID: PMC8257655 DOI: 10.1038/s41467-021-24423-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 06/18/2021] [Indexed: 01/02/2023] Open
Abstract
Feeding decisions are fundamental to survival, and decision making is often disrupted in disease. Here, we show that neural activity in a small population of neurons projecting to the fan-shaped body higher-order central brain region of Drosophila represents food choice during sensory conflict. We found that food deprived flies made tradeoffs between appetitive and aversive values of food. We identified an upstream neuropeptidergic and dopaminergic network that relays internal state and other decision-relevant information to a specific subset of fan-shaped body neurons. These neurons were strongly inhibited by the taste of the rejected food choice, suggesting that they encode behavioral food choice. Our findings reveal that fan-shaped body taste responses to food choices are determined not only by taste quality, but also by previous experience (including choice outcome) and hunger state, which are integrated in the fan-shaped body to encode the decision before relay to downstream motor circuits for behavioral implementation.
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Affiliation(s)
- Preeti F Sareen
- Department of Cellular and Molecular Physiology, Yale University, New Haven, CT, USA
| | - Li Yan McCurdy
- Department of Cellular and Molecular Physiology, Yale University, New Haven, CT, USA
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT, USA
| | - Michael N Nitabach
- Department of Cellular and Molecular Physiology, Yale University, New Haven, CT, USA.
- Department of Genetics, Yale University, New Haven, CT, USA.
- Department of Neuroscience, Yale University, New Haven, CT, USA.
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9
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Lau CKS, Jelen M, Gordon MD. A closed-loop optogenetic screen for neurons controlling feeding in Drosophila. G3-GENES GENOMES GENETICS 2021; 11:6170659. [PMID: 33714999 PMCID: PMC8104954 DOI: 10.1093/g3journal/jkab073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 03/03/2021] [Indexed: 11/14/2022]
Abstract
Feeding is an essential part of animal life that is greatly impacted by the sense of taste. Although the characterization of taste-detection at the periphery has been extensive, higher order taste and feeding circuits are still being elucidated. Here, we use an automated closed-loop optogenetic activation screen to detect novel taste and feeding neurons in Drosophila melanogaster. Out of 122 Janelia FlyLight Project GAL4 lines preselected based on expression pattern, we identify six lines that acutely promote feeding and 35 lines that inhibit it. As proof of principle, we follow up on R70C07-GAL4, which labels neurons that strongly inhibit feeding. Using split-GAL4 lines to isolate subsets of the R70C07-GAL4 population, we find both appetitive and aversive neurons. Furthermore, we show that R70C07-GAL4 labels putative second-order taste interneurons that contact both sweet and bitter sensory neurons. These results serve as a resource for further functional dissection of fly feeding circuits.
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Affiliation(s)
- Celia K S Lau
- Department of Zoology and Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Meghan Jelen
- Department of Zoology and Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Michael D Gordon
- Department of Zoology and Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
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10
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Perez-Alvarez A, Fearey BC, O'Toole RJ, Yang W, Arganda-Carreras I, Lamothe-Molina PJ, Moeyaert B, Mohr MA, Panzera LC, Schulze C, Schreiter ER, Wiegert JS, Gee CE, Hoppa MB, Oertner TG. Freeze-frame imaging of synaptic activity using SynTagMA. Nat Commun 2020; 11:2464. [PMID: 32424147 PMCID: PMC7235013 DOI: 10.1038/s41467-020-16315-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 04/23/2020] [Indexed: 12/16/2022] Open
Abstract
Information within the brain travels from neuron to neuron across billions of synapses. At any given moment, only a small subset of neurons and synapses are active, but finding the active synapses in brain tissue has been a technical challenge. Here we introduce SynTagMA to tag active synapses in a user-defined time window. Upon 395-405 nm illumination, this genetically encoded marker of activity converts from green to red fluorescence if, and only if, it is bound to calcium. Targeted to presynaptic terminals, preSynTagMA allows discrimination between active and silent axons. Targeted to excitatory postsynapses, postSynTagMA creates a snapshot of synapses active just before photoconversion. To analyze large datasets, we show how to identify and track the fluorescence of thousands of individual synapses in an automated fashion. Together, these tools provide an efficient method for repeatedly mapping active neurons and synapses in cell culture, slice preparations, and in vivo during behavior.
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Affiliation(s)
- Alberto Perez-Alvarez
- Institute for Synaptic Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, D-20251, Germany
| | - Brenna C Fearey
- Institute for Synaptic Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, D-20251, Germany
| | - Ryan J O'Toole
- Department of Biological Sciences, Dartmouth College, Hanover, NH, 03755, USA
| | - Wei Yang
- Research Group Synaptic Wiring and Information Processing, University Medical Center Hamburg-Eppendorf, Hamburg, D-20251, Germany
| | - Ignacio Arganda-Carreras
- Ikerbasque, Basque Foundation for Science, Bilbao, Spain
- Dept. of Computer Science and Artificial Intelligence, Basque Country University, San Sebastian, Spain
- Donostia International Physics Center (DIPC), San Sebastian, Spain
| | - Paul J Lamothe-Molina
- Institute for Synaptic Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, D-20251, Germany
| | | | - Manuel A Mohr
- HHMI, Janelia Farm Research Campus, Ashburn, VA, 20147, USA
| | - Lauren C Panzera
- Department of Biological Sciences, Dartmouth College, Hanover, NH, 03755, USA
| | - Christian Schulze
- Institute for Synaptic Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, D-20251, Germany
| | | | - J Simon Wiegert
- Research Group Synaptic Wiring and Information Processing, University Medical Center Hamburg-Eppendorf, Hamburg, D-20251, Germany
| | - Christine E Gee
- Institute for Synaptic Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, D-20251, Germany
| | - Michael B Hoppa
- Department of Biological Sciences, Dartmouth College, Hanover, NH, 03755, USA
| | - Thomas G Oertner
- Institute for Synaptic Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, D-20251, Germany.
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11
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Edwards KA, Hoppa MB, Bosco G. The Photoconvertible Fluorescent Probe, CaMPARI, Labels Active Neurons in Freely-Moving Intact Adult Fruit Flies. Front Neural Circuits 2020; 14:22. [PMID: 32457580 PMCID: PMC7227398 DOI: 10.3389/fncir.2020.00022] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 04/14/2020] [Indexed: 01/27/2023] Open
Abstract
Linking neural circuitry to behavior by mapping active neurons in vivo is a challenge. Both genetically encoded calcium indicators (GECIs) and intermediate early genes (IEGs) have been used to pinpoint active neurons during a stimulus or behavior but have drawbacks such as limiting the movement of the organism, requiring a priori knowledge of the active region or having poor temporal resolution. Calcium-modulated photoactivatable ratiometric integrator (CaMPARI) was engineered to overcome these spatial-temporal challenges. CaMPARI is a photoconvertible protein that only converts from green to red fluorescence in the presence of high calcium concentration and 405 nm light. This allows the experimenter to precisely mark active neurons within defined temporal windows. The photoconversion can then be quantified by taking the ratio of the red fluorescence to the green. CaMPARI promises the ability to trace active neurons during a specific stimulus; however, CaMPARI's uses in adult Drosophila have been limited to photoconversion during fly immobilization. Here, we demonstrate a method that allows photoconversion of multiple freely-moving intact adult flies during a stimulus. Flies were placed in a dish with filter paper wet with acetic acid (pH = 2) or neutralized acetic acid (pH = 7) and exposed to photoconvertible light (60 mW) for 30 min (500 ms on, 200 ms off). Immediately following photoconversion, whole flies were fixed and imaged by confocal microscopy. The red:green ratio was quantified for the DC4 glomerulus, a bundle of neurons expressing Ir64a, an ionotropic receptor that senses acids in the Drosophila antennal lobe. Flies exposed to acetic acid showed 1.3-fold greater photoconversion than flies exposed to neutralized acetic acid. This finding was recapitulated using a more physiological stimulus of apple cider vinegar. These results indicate that CaMPARI can be used to label neurons in intact, freely-moving adult flies and will be useful for identifying the circuitry underlying complex behaviors.
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Affiliation(s)
- Katie A. Edwards
- Department of Molecular and Systems Biology, Geisel School of Medicine, Dartmouth College, Hanover, NH, United States
| | - Michael B. Hoppa
- Department of Biological Sciences, Dartmouth College, Hanover, NH, United States
| | - Giovanni Bosco
- Department of Molecular and Systems Biology, Geisel School of Medicine, Dartmouth College, Hanover, NH, United States
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12
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Mahishi D, Huetteroth W. The prandial process in flies. CURRENT OPINION IN INSECT SCIENCE 2019; 36:157-166. [PMID: 31765996 DOI: 10.1016/j.cois.2019.09.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 09/03/2019] [Accepted: 09/18/2019] [Indexed: 06/10/2023]
Abstract
Feeding is fundamental to any heterotroph organism; in its role to quell hunger it overrides most other motivational states. But feeding also literally opens the door to harmful risks, especially for a saprophagous animal like Drosophila; ingestion of poisonous substrate can lead to irreversible damage. Thus feeding incorporates a series of steps with several checkpoints to guarantee that the ingestion remains beneficial and provides a balanced diet, or the feeding process is interrupted. Subsequently, we will summarize and describe the feeding process in Drosophila in a comprehensive manner. We propose eleven distinct steps for feeding, grouped into four categories, to address our current knowledge of prandial regulatory mechanisms in Drosophila.
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Affiliation(s)
- Deepthi Mahishi
- Department of Biology, University of Leipzig, Leipzig, Germany
| | - Wolf Huetteroth
- Department of Biology, University of Leipzig, Leipzig, Germany.
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13
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Chen YCD, Ahmad S, Amin K, Dahanukar A. A subset of brain neurons controls regurgitation in adult Drosophila melanogaster. J Exp Biol 2019; 222:jeb210724. [PMID: 31511344 PMCID: PMC6806010 DOI: 10.1242/jeb.210724] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 09/03/2019] [Indexed: 12/26/2022]
Abstract
Taste is essential for animals to evaluate food quality and make important decisions about food choice and intake. How complex brains process sensory information to produce behavior is an essential question in the field of sensory neurobiology. Currently, little is known about higher-order taste circuits in the brain as compared with those of other sensory systems. Here, we used the common vinegar fly, Drosophila melanogaster, to screen for candidate neurons labeled by different transgenic GAL4 lines in controlling feeding behaviors. We found that activation of one line (VT041723-GAL4) produces 'proboscis holding' behavior (extrusion of the mouthpart without withdrawal). Further analysis showed that the proboscis holding phenotype indicates an aversive response, as flies pre-fed with either sucrose or water prior to neuronal activation exhibited regurgitation. Anatomical characterization of VT041723-GAL4-labeled neurons suggests that they receive sensory input from peripheral taste neurons. Overall, our study identifies a subset of brain neurons labeled by VT041723-GAL4 that may be involved in a taste circuit that controls regurgitation.
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Affiliation(s)
- Yu-Chieh David Chen
- Interdepartmental Neuroscience Program, University of California, Riverside, CA 92521, USA
| | - Sameera Ahmad
- Department of Biology, University of California, Riverside, CA 92521, USA
| | - Kush Amin
- Department of Biology, University of California, Riverside, CA 92521, USA
| | - Anupama Dahanukar
- Interdepartmental Neuroscience Program, University of California, Riverside, CA 92521, USA
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, CA 92521, USA
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14
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Molecular control limiting sensitivity of sweet taste neurons in Drosophila. Proc Natl Acad Sci U S A 2019; 116:20158-20168. [PMID: 31527261 DOI: 10.1073/pnas.1911583116] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
To assess the biological value of environmental stimuli, animals' sensory systems must accurately decode both the identities and the intensities of these stimuli. While much is known about the mechanism by which sensory neurons detect the identities of stimuli, less is known about the mechanism that controls how sensory neurons respond appropriately to different intensities of stimuli. The ionotropic receptor IR76b has been shown to be expressed in different Drosophila chemosensory neurons for sensing a variety of chemicals. Here, we show that IR76b plays an unexpected role in lowering the sensitivity of Drosophila sweet taste neurons. First, IR76b mutants exhibited clear behavioral responses to sucrose and acetic acid (AA) at concentrations that were too low to trigger observable behavioral responses from WT animals. Second, IR76b is expressed in many sweet neurons on the labellum, and these neurons responded to both sucrose and AA. Removing IR76b from the sweet neurons increased their neuronal responses as well as animals' behavioral responses to sucrose and AA. Conversely, overexpressing IR76b in the sweet neurons decreased their neuronal as well as animals' behavioral responses to sucrose and AA. Last, IR76b's response-lowering ability has specificity: IR76b mutants and WT showed comparable responses to capsaicin when the mammalian capsaicin receptor VR1 was ectopically expressed in their sweet neurons. Our findings suggest that sensitivity of Drosophila sweet neurons to their endogenous ligands is actively limited by IR76b and uncover a potential molecular target by which contexts can modulate sensitivity of sweet neurons.
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15
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Guo C, Pan Y, Gong Z. Recent Advances in the Genetic Dissection of Neural Circuits in Drosophila. Neurosci Bull 2019; 35:1058-1072. [PMID: 31119647 DOI: 10.1007/s12264-019-00390-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 12/17/2018] [Indexed: 11/28/2022] Open
Abstract
Nervous systems endow animals with cognition and behavior. To understand how nervous systems control behavior, neural circuits mediating distinct functions need to be identified and characterized. With superior genetic manipulability, Drosophila is a model organism at the leading edge of neural circuit analysis. We briefly introduce the state-of-the-art genetic tools that permit precise labeling of neurons and their interconnectivity and investigating what is happening in the brain of a behaving animal and manipulating neurons to determine how behaviors are affected. Brain-wide wiring diagrams, created by light and electron microscopy, bring neural circuit analysis to a new level and scale. Studies enabled by these tools advances our understanding of the nervous system in relation to cognition and behavior.
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Affiliation(s)
- Chao Guo
- Key Laboratory of Developmental Genes and Human Disease of the Ministry of Education of China, Institute of Life Sciences, Southeast University, Nanjing, 210096, China.
| | - Yufeng Pan
- Key Laboratory of Developmental Genes and Human Disease of the Ministry of Education of China, Institute of Life Sciences, Southeast University, Nanjing, 210096, China
| | - Zhefeng Gong
- Department of Neurobiology, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Key Laboratory of Neurobiology, Zhejiang University School of Medicine, Hangzhou, 310058, China
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Kaushik S, Kumar R, Kain P. Salt an Essential Nutrient: Advances in Understanding Salt Taste Detection Using Drosophila as a Model System. J Exp Neurosci 2018; 12:1179069518806894. [PMID: 30479487 PMCID: PMC6249657 DOI: 10.1177/1179069518806894] [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: 05/10/2018] [Accepted: 09/19/2018] [Indexed: 11/16/2022] Open
Abstract
Taste modalities are conserved in insects and mammals. Sweet gustatory signals evoke attractive behaviors while bitter gustatory information drive aversive behaviors. Salt (NaCl) is an essential nutrient required for various physiological processes, including electrolyte homeostasis, neuronal activity, nutrient absorption, and muscle contraction. Not only mammals, even in Drosophila melanogaster, the detection of NaCl induces two different behaviors: Low concentrations of NaCl act as an attractant, whereas high concentrations act as repellant. The fruit fly is an excellent model system for studying the underlying mechanisms of salt taste due to its relatively simple neuroanatomical organization of the brain and peripheral taste system, the availability of powerful genetic tools and transgenic strains. In this review, we have revisited the literature and the information provided by various laboratories using invertebrate model system Drosophila that has helped us to understand NaCl salt taste so far. We hope that this compiled information from Drosophila will be of general significance and interest for forthcoming studies of the structure, function, and behavioral role of NaCl-sensitive (low and high concentrations) gustatory circuitry for understanding NaCl salt taste in all animals.
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Affiliation(s)
- Shivam Kaushik
- Department of Neurobiology and Genetics, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, India
| | - Rahul Kumar
- Department of Neurobiology and Genetics, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, India.,Department of Biotechnology, Maharshi Dayanand University, Rohtak, India
| | - Pinky Kain
- Department of Neurobiology and Genetics, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, India
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