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Yu H, Song L, Duan X, Zhu D, Li N, Pan R, Xu R, Yu X, Ye F, Jiang X, Ye H, Pan Z, Wei S, Jiang Z. Optogenetics in taste research: A decade of enlightenment. Oral Dis 2024; 30:903-913. [PMID: 36620868 DOI: 10.1111/odi.14498] [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: 07/28/2022] [Revised: 12/03/2022] [Accepted: 01/05/2023] [Indexed: 01/10/2023]
Abstract
The electrophysiological function of the tongue involves complicated activities in taste sense, producing the perceptions of salty, sweet, bitter, and sour. However, therapies and prevention of taste loss arising from dysfunction in electrophysiological activity require further fundamental research. Optogenetics has revolutionized neuroscience and brought the study of sensory system to a higher level in taste. The year 2022 marks a decade of developments of optogenetics in taste since this technology was adopted from neuroscience and applied to the taste research. This review summarizes a decade of advances that define near-term translation with optogenetic tools, and newly-discovered mechanisms with the applications of these tools. The main limitations and opportunities for optogenetics in taste research are also discussed.
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Affiliation(s)
- Hanshu Yu
- Zhejiang University School of Medicine, Hangzhou, China
| | - Luyao Song
- Zhejiang University School of Medicine, Hangzhou, China
| | - Xiangyao Duan
- Zhejiang University School of Medicine, Hangzhou, China
| | - Danji Zhu
- Key Laboratory of Oral Biomedical Research of Zhejiang Province, School of Stomatology, Zhejiang Provincial Clinical Research Centre for Oral Diseases, Cancer Centre of Zhejiang University, Stomatology Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Na Li
- Key Laboratory of Oral Biomedical Research of Zhejiang Province, School of Stomatology, Zhejiang Provincial Clinical Research Centre for Oral Diseases, Cancer Centre of Zhejiang University, Stomatology Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Runxin Pan
- Zhejiang University School of Medicine, Hangzhou, China
| | - Rui Xu
- Zhejiang University School of Medicine, Hangzhou, China
| | - Xinying Yu
- Zhejiang University School of Medicine, Hangzhou, China
| | - Fengkai Ye
- Zhejiang University School of Medicine, Hangzhou, China
| | - Xinrui Jiang
- Zhejiang University School of Medicine, Hangzhou, China
| | - Han Ye
- Zhejiang University School of Medicine, Hangzhou, China
| | - Zikang Pan
- Zhejiang University School of Medicine, Hangzhou, China
| | - Sixing Wei
- Zhejiang University School of Medicine, Hangzhou, China
| | - Zhiwei Jiang
- Key Laboratory of Oral Biomedical Research of Zhejiang Province, School of Stomatology, Zhejiang Provincial Clinical Research Centre for Oral Diseases, Cancer Centre of Zhejiang University, Stomatology Hospital, Zhejiang University School of Medicine, Hangzhou, China
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2
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Ortega-Insaurralde I, Latorre-Estivalis JM, Costa-da-Silva AL, Cano A, Insausti TC, Morales HS, Pontes G, de Astrada MB, Ons S, DeGennaro M, Barrozo RB. The pharyngeal taste organ of a blood-feeding insect functions in food recognition. BMC Biol 2024; 22:63. [PMID: 38481317 PMCID: PMC10938694 DOI: 10.1186/s12915-024-01861-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 03/06/2024] [Indexed: 03/17/2024] Open
Abstract
BACKGROUND Obligate blood-feeding insects obtain the nutrients and water necessary to ensure survival from the vertebrate blood. The internal taste sensilla, situated in the pharynx, evaluate the suitability of the ingested food. Here, through multiple approaches, we characterized the pharyngeal organ (PO) of the hematophagous kissing bug Rhodnius prolixus to determine its role in food assessment. The PO, located antero-dorsally in the pharynx, comprises eight taste sensilla that become bathed with the incoming blood. RESULTS We showed that these taste sensilla house gustatory receptor neurons projecting their axons through the labral nerves to reach the subesophageal zone in the brain. We found that these neurons are electrically activated by relevant appetitive and aversive gustatory stimuli such as NaCl, ATP, and caffeine. Using RNA-Seq, we examined the expression of sensory-related gene families in the PO. We identified gustatory receptors, ionotropic receptors, transient receptor potential channels, pickpocket channels, opsins, takeouts, neuropeptide precursors, neuropeptide receptors, and biogenic amine receptors. RNA interference assays demonstrated that the salt-related pickpocket channel Rproppk014276 is required during feeding of an appetitive solution of NaCl and ATP. CONCLUSIONS We provide evidence of the role of the pharyngeal organ in food evaluation. This work shows a comprehensive characterization of a pharyngeal taste organ in a hematophagous insect.
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Affiliation(s)
- Isabel Ortega-Insaurralde
- Laboratorio de Neuroetología de Insectos, Departamento Biodiversidad y Biología Experimental (DBBE), Instituto Biodiversidad Biología Experimental y Aplicada (IBBEA), CONICET, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - José Manuel Latorre-Estivalis
- Laboratorio de Insectos Sociales, Instituto de Fisiología Biología Molecular y Neurociencias (IFIBYNE), CONICET, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Andre Luis Costa-da-Silva
- Department of Biological Sciences and Biomolecular Sciences Institute, Florida International University, Miami, FL, USA
| | - Agustina Cano
- Laboratorio de Neuroetología de Insectos, Departamento Biodiversidad y Biología Experimental (DBBE), Instituto Biodiversidad Biología Experimental y Aplicada (IBBEA), CONICET, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | | | - Héctor Salas Morales
- Laboratorio de Neuroetología de Insectos, Departamento Biodiversidad y Biología Experimental (DBBE), Instituto Biodiversidad Biología Experimental y Aplicada (IBBEA), CONICET, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Gina Pontes
- Laboratorio de Ecofisiología de Insectos, Departamento Biodiversidad y Biología Experimental (DBBE), Instituto Biodiversidad Biología Experimental y Aplicada (IBBEA), CONICET, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Martín Berón de Astrada
- Laboratorio de Fisiología de la Visión, Departamento de Fisiología Biología Molecular y Celular (FBMC), Instituto de Biociencias Biotecnología y Biología Traslacional (IB3), Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Sheila Ons
- Laboratorio de Neurobiología de Insectos, Facultad de Ciencias Exactas (CENEXA), Centro Regional de Estudios Genómicos, CONICET, Universidad Nacional de La Plata, La Plata, Buenos Aires, Argentina
| | - Matthew DeGennaro
- Department of Biological Sciences and Biomolecular Sciences Institute, Florida International University, Miami, FL, USA
| | - Romina B Barrozo
- Laboratorio de Neuroetología de Insectos, Departamento Biodiversidad y Biología Experimental (DBBE), Instituto Biodiversidad Biología Experimental y Aplicada (IBBEA), CONICET, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina.
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Miyashita T, Murakami K, Kikuchi E, Ofusa K, Mikami K, Endo K, Miyaji T, Moriyama S, Konno K, Muratani H, Moriyama Y, Watanabe M, Horiuchi J, Saitoe M. Glia transmit negative valence information during aversive learning in Drosophila. Science 2023; 382:eadf7429. [PMID: 38127757 DOI: 10.1126/science.adf7429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 10/20/2023] [Indexed: 12/23/2023]
Abstract
During Drosophila aversive olfactory conditioning, aversive shock information needs to be transmitted to the mushroom bodies (MBs) to associate with odor information. We report that aversive information is transmitted by ensheathing glia (EG) that surround the MBs. Shock induces vesicular exocytosis of glutamate from EG. Blocking exocytosis impairs aversive learning, whereas activation of EG can replace aversive stimuli during conditioning. Glutamate released from EG binds to N-methyl-d-aspartate receptors in the MBs, but because of Mg2+ block, Ca2+ influx occurs only when flies are simultaneously exposed to an odor. Vesicular exocytosis from EG also induces shock-associated dopamine release, which plays a role in preventing formation of inappropriate associations. These results demonstrate that vesicular glutamate released from EG transmits negative valence information required for associative learning.
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Affiliation(s)
- Tomoyuki Miyashita
- Learning and Memory Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - Kanako Murakami
- Learning and Memory Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
- Department of Biological Science, Graduate School of Science, Tokyo Metropolitan University, Tokyo 192-0397, Japan
| | - Emi Kikuchi
- Learning and Memory Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - Kyouko Ofusa
- Learning and Memory Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - Kyohei Mikami
- Center for Basic Technology Research, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - Kentaro Endo
- Center for Basic Technology Research, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - Takaaki Miyaji
- Department of Molecular Membrane Biology, Faculty of Pharmaceutical Sciences, Okayama University, Okayama 700-8530, Japan
- Department of Genomics and Proteomics, Advanced Science Research Center, Okayama University, Okayama 700-8530, Japan
| | - Sawako Moriyama
- Division of Endocrinology and Metabolism, Department of Internal Medicine, School of Medicine, Kurume University, Fukuoka 830-0011, Japan
| | - Kotaro Konno
- Department of Anatomy, Faculty of Medicine, Hokkaido University, Hokkaido 060-8368, Japan
| | - Hinako Muratani
- Learning and Memory Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
- Department of Engineering Science, Graduate School of Informatics and Engineering, The University of Electro-Communications, Tokyo 182-8585, Japan
| | - Yoshinori Moriyama
- Division of Endocrinology and Metabolism, Department of Internal Medicine, School of Medicine, Kurume University, Fukuoka 830-0011, Japan
| | - Masahiko Watanabe
- Department of Anatomy, Faculty of Medicine, Hokkaido University, Hokkaido 060-8368, Japan
| | - Junjiro Horiuchi
- Center for Basic Technology Research, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - Minoru Saitoe
- Learning and Memory Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
- Center for Basic Technology Research, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
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4
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Dey M, Brown E, Charlu S, Keene A, Dahanukar A. Evolution of fatty acid taste in drosophilids. Cell Rep 2023; 42:113297. [PMID: 37864792 PMCID: PMC10697176 DOI: 10.1016/j.celrep.2023.113297] [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: 02/06/2023] [Revised: 09/01/2023] [Accepted: 10/02/2023] [Indexed: 10/23/2023] Open
Abstract
Comparative studies of related but ecologically distinct species can reveal how the nervous system evolves to drive behaviors that are particularly suited to certain environments. Drosophila melanogaster is a generalist that feeds and oviposits on most overripe fruits. A sibling species, D. sechellia, is an obligate specialist of Morinda citrifolia (noni) fruit, which is rich in fatty acids (FAs). To understand evolution of noni taste preference, we characterized behavioral and cellular responses to noni-associated FAs in three related drosophilids. We find that mixtures of sugar and noni FAs evoke strong aversion in the generalist species but not in D. sechellia. Surveys of taste sensory responses reveal noni FA- and species-specific differences in at least two mechanisms-bitter neuron activation and sweet neuron inhibition-that correlate with shifts in noni preference. Chemoreceptor mutant analysis in D. melanogaster predicts that multiple genetic changes account for evolution of gustatory preference in D. sechellia.
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Affiliation(s)
- Manali Dey
- Interdepartmental Neuroscience Program, University of California, Riverside, Riverside, CA 92521, USA
| | - Elizabeth Brown
- Department of Biology, Texas A&M University, College Station, TX 77843, USA
| | - Sandhya Charlu
- Biomedical Sciences Graduate Program, University of California, Riverside, Riverside, CA 92521, USA
| | - Alex Keene
- Department of Biology, Texas A&M University, College Station, TX 77843, USA
| | - Anupama Dahanukar
- Interdepartmental Neuroscience Program, University of California, Riverside, Riverside, CA 92521, USA; Biomedical Sciences Graduate Program, University of California, Riverside, Riverside, CA 92521, USA; Department of Molecular, Cell & Systems Biology, University of California, Riverside, Riverside, CA 92521, USA.
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5
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Coomer C, Naumova D, Talay M, Zolyomi B, Snell N, Sorkac A, Chanchu JM, Cheng J, Roman I, Li J, Robson D, Barnea G, Halpern ME. Transsynaptic labeling and transcriptional control of zebrafish neural circuits. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.03.535421. [PMID: 37066422 PMCID: PMC10103993 DOI: 10.1101/2023.04.03.535421] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/18/2023]
Abstract
Deciphering the connectome, the ensemble of synaptic connections that underlie brain function is a central goal of neuroscience research. The trans-Tango genetic approach, initially developed for anterograde transsynaptic tracing in Drosophila, can be used to map connections between presynaptic and postsynaptic partners and to drive gene expression in target neurons. Here, we describe the successful adaptation of trans-Tango to visualize neural connections in a living vertebrate nervous system, that of the zebrafish. Connections were validated between synaptic partners in the larval retina and brain. Results were corroborated by functional experiments in which optogenetic activation of retinal ganglion cells elicited responses in neurons of the optic tectum, as measured by trans-Tango-dependent expression of a genetically encoded calcium indicator. Transsynaptic signaling through trans-Tango reveals predicted as well as previously undescribed synaptic connections, providing a valuable in vivo tool to monitor and interrogate neural circuits over time.
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6
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Benton R, Dahanukar A. Chemosensory Coding in Drosophila Single Sensilla. Cold Spring Harb Protoc 2023; 2023:107803-pdb.top. [PMID: 36446528 DOI: 10.1101/pdb.top107803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The chemical senses-smell and taste-detect and discriminate an enormous diversity of environmental stimuli and provide fascinating but challenging models to investigate how sensory cues are represented in the brain. Important stimulus-coding events occur in peripheral sensory neurons, which express specific combinations of chemosensory receptors with defined ligand-response profiles. These receptors convert ligand recognition into spatial and temporal patterns of neural activity that are transmitted to, and interpreted in, central brain regions. Drosophila melanogaster provides an attractive model to study chemosensory coding because it possesses relatively simple peripheral olfactory and gustatory systems that display many organizational parallels to those of vertebrates. Moreover, nearly all peripheral chemosensory neurons have been molecularly characterized and are accessible for physiological analysis, as they are exposed on the surface of sensory organs housed in specialized hairs called sensilla. Here, we briefly review anatomical, molecular, and physiological properties of adult Drosophila olfactory and gustatory systems and provide background to methods for electrophysiological recordings of ligand-evoked activity from different types of chemosensory sensilla.
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Affiliation(s)
- Richard Benton
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Anupama Dahanukar
- Department of Molecular, Cell & Systems Biology, University of California, Riverside, California 92521, USA
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7
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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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8
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Dey M, Ganguly A, Dahanukar A. An inhibitory mechanism for suppressing high salt intake in Drosophila. Chem Senses 2023; 48:bjad014. [PMID: 37201555 PMCID: PMC10413321 DOI: 10.1093/chemse/bjad014] [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: 08/15/2022] [Indexed: 05/20/2023] Open
Abstract
High concentrations of dietary salt are harmful to health. Like most animals, Drosophila melanogaster are attracted to foods that have low concentrations of salt, but show strong taste avoidance of high salt foods. Salt in known on multiple classes of taste neurons, activating Gr64f sweet-sensing neurons that drive food acceptance and 2 others (Gr66a bitter and Ppk23 high salt) that drive food rejection. Here we find that NaCl elicits a bimodal dose-dependent response in Gr64f taste neurons, which show high activity with low salt and depressed activity with high salt. High salt also inhibits the sugar response of Gr64f neurons, and this action is independent of the neuron's taste response to salt. Consistent with the electrophysiological analysis, feeding suppression in the presence of salt correlates with inhibition of Gr64f neuron activity, and remains if high salt taste neurons are genetically silenced. Other salts such as Na2SO4, KCl, MgSO4, CaCl2, and FeCl3 act on sugar response and feeding behavior in the same way. A comparison of the effects of various salts suggests that inhibition is dictated by the cationic moiety rather than the anionic component of the salt. Notably, high salt-dependent inhibition is not observed in Gr66a neurons-response to a canonical bitter tastant, denatonium, is not altered by high salt. Overall, this study characterizes a mechanism in appetitive Gr64f neurons that can deter ingestion of potentially harmful salts.
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Affiliation(s)
- Manali Dey
- Interdepartmental Neuroscience Program, University of California, Riverside, CA 92521, United States
| | - Anindya Ganguly
- Interdepartmental Neuroscience Program, University of California, Riverside, CA 92521, United States
| | - Anupama Dahanukar
- Interdepartmental Neuroscience Program, University of California, Riverside, CA 92521, United States
- Department of Molecular, Cell & Systems Biology, University of California, Riverside, CA 92521, United States
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9
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McDowell SAT, Stanley M, Gordon MD. A molecular mechanism for high salt taste in Drosophila. Curr Biol 2022; 32:3070-3081.e5. [PMID: 35772408 DOI: 10.1016/j.cub.2022.06.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 05/04/2022] [Accepted: 06/07/2022] [Indexed: 11/25/2022]
Abstract
Dietary salt detection and consumption are crucial to maintaining fluid and ionic homeostasis. To optimize salt intake, animals employ salt-dependent activation of multiple taste pathways. Generally, sodium activates attractive taste cells, but attraction is overridden at high salt concentrations by cation non-selective activation of aversive taste cells. In flies, high salt avoidance is driven by both "bitter" taste neurons and a class of glutamatergic "high salt" neurons expressing pickpocket23 (ppk23). Although the cellular basis of salt taste has been described, many of the molecular mechanisms remain elusive. Here, we show that ionotropic receptor 7c (IR7c) is expressed in glutamatergic high salt neurons, where it functions with co-receptors IR76b and IR25a to detect high salt and is essential for monovalent salt taste. Misexpression of IR7c in sweet neurons, which endogenously express IR76b and IR25a, confers responsiveness to non-sodium salts, indicating that IR7c is sufficient to convert a sodium-selective gustatory receptor neuron to a cation non-selective one. Furthermore, the resultant transformation of taste neuron tuning switches potassium chloride from an aversive to an attractive tastant. This research provides insight into the molecular basis of monovalent and divalent salt-taste coding.
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Affiliation(s)
- Sasha A T McDowell
- Department of Zoology and Life Sciences Institute, The University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Molly Stanley
- Department of Zoology and Life Sciences Institute, The University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Michael D Gordon
- Department of Zoology and Life Sciences Institute, The University of British Columbia, Vancouver, BC V6T 1Z3, Canada.
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Abstract
The Anthropocene Epoch poses a critical challenge for organisms: they must cope with new threats at a rapid rate. These threats include toxic chemical compounds released into the environment by human activities. Here, we examine elevated concentrations of heavy metal ions as an example of anthropogenic stressors. We find that the fruit fly Drosophila avoids nine metal ions when present at elevated concentrations that the flies experienced rarely, if ever, until the Anthropocene. We characterize the avoidance of feeding and egg laying on metal ions, and we identify receptors, neurons, and taste organs that contribute to this avoidance. Different subsets of taste receptors, including members of both Ir (Ionotropic receptor) and Gr (Gustatory receptor) families contribute to the avoidance of different metal ions. We find that metal ions activate certain bitter-sensing neurons and inhibit sugar-sensing neurons. Some behavioral responses are mediated largely through neurons of the pharynx. Feeding avoidance remains stable over 10 generations of exposure to copper and zinc ions. Some responses to metal ions are conserved across diverse dipteran species, including the mosquito Aedes albopictus. Our results suggest mechanisms that may be essential to insects as they face challenges from environmental changes in the Anthropocene.
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11
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Aryal B, Dhakal S, Shrestha B, Sang J, Nhuchhen Pradhan R, Lee Y. Protocol for binary food choice assays using Drosophila melanogaster. STAR Protoc 2022; 3:101410. [PMID: 35620079 PMCID: PMC9127214 DOI: 10.1016/j.xpro.2022.101410] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Food preference is a fundamental behavior for animals to choose nutritious foods while rejecting foods containing toxins. Here, we describe binary food choice assays using Drosophila melanogaster, which are straightforward approaches for the characterization of two-way choice tastants. We detail the preparation of flies and dye-containing food, followed by the binary-choice feeding assays and the determination of the preference index (PI). This protocol is simple, sensitive, and reproducible in qualitatively detecting attractive or aversive characteristics toward any two-way choice tastants. For complete details on the use and execution of this protocol, please refer to Aryal et al. (2022). Protocol for qualitatively analyzing food preferences in Drosophila A simple, sensitive, and reproducible binary food choice assay Determination of preference index using dye-containing foods Appropriate for any behavioral taste analysis of fly models
Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics.
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Affiliation(s)
- Binod Aryal
- Department of Bio & Fermentation Convergence Technology, Kookmin University, Seoul 02707, Republic of Korea
| | - Subash Dhakal
- Department of Bio & Fermentation Convergence Technology, Kookmin University, Seoul 02707, Republic of Korea
| | - Bhanu Shrestha
- Department of Bio & Fermentation Convergence Technology, Kookmin University, Seoul 02707, Republic of Korea
| | - Jiun Sang
- Department of Bio & Fermentation Convergence Technology, Kookmin University, Seoul 02707, Republic of Korea
| | - Roshani Nhuchhen Pradhan
- Department of Bio & Fermentation Convergence Technology, Kookmin University, Seoul 02707, Republic of Korea
| | - Youngseok Lee
- Department of Bio & Fermentation Convergence Technology, Kookmin University, Seoul 02707, Republic of Korea
- Corresponding author
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12
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Identification of additional dye tracers for measuring solid food intake and food preference via consumption-excretion in Drosophila. Sci Rep 2022; 12:6201. [PMID: 35418664 PMCID: PMC9008003 DOI: 10.1038/s41598-022-10252-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 04/01/2022] [Indexed: 11/08/2022] Open
Abstract
The Drosophila model has become a leading platform for investigating mechanisms that drive feeding behavior and the effect of diet on physiological outputs. Several methods for tracking feeding behavior in flies have been developed. One method, consumption-excretion or Con-Ex, provides flies with media labeled with dye and then quantifies the amount of dye excreted into the vial as a measure of consumption. We previously found that Blue 1 and Orange 4 work well in Con-Ex and can be used as a dye pair in food preference studies. We have expanded our development of Con-Ex by identifying two additional dyes, Orange G and Yellow 10, that detect the anticipated effects of mating status, strain, starvation and nutrient concentration. Additionally, Orange G and Yellow 10 accumulate linearly in excretion products out to 48 h and the excreted volumes of these two dyes reflect the volumes consumed. Orange G also works with Blue 1 as a dye pair in food preference studies. Finally, consumption of Blue 1, Orange 4, Orange G or Yellow 10 does not affect ethanol sedation or rapid tolerance to ethanol. Our findings establish that Orange G and Yellow 10, like Blue 1 and Orange 4, are suitable for use in Con-Ex.
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Dhakal S, Sang J, Aryal B, Lee Y. Ionotropic receptors mediate nitrogenous waste avoidance in Drosophila melanogaster. Commun Biol 2021; 4:1281. [PMID: 34773080 PMCID: PMC8589963 DOI: 10.1038/s42003-021-02799-3] [Citation(s) in RCA: 10] [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: 04/27/2021] [Accepted: 10/19/2021] [Indexed: 01/03/2023] Open
Abstract
Ammonia and its amine-containing derivatives are widely found in natural decomposition byproducts. Here, we conducted biased chemoreceptor screening to investigate the mechanisms by which different concentrations of ammonium salt, urea, and putrescine in rotten fruits affect feeding and oviposition behavior. We identified three ionotropic receptors, including the two broadly required IR25a and IR76b receptors, as well as the narrowly tuned IR51b receptor. These three IRs were fundamental in eliciting avoidance against nitrogenous waste products, which is mediated by bitter-sensing gustatory receptor neurons (GRNs). The aversion of nitrogenous wastes was evaluated by the cellular requirement by expressing Kir2.1 and behavioral recoveries of the mutants in bitter-sensing GRNs. Furthermore, by conducting electrophysiology assays, we confirmed that ammonia compounds are aversive in taste as they directly activated bitter-sensing GRNs. Therefore, our findings provide insights into the ecological roles of IRs as a means to detect and avoid toxic nitrogenous waste products in nature.
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Affiliation(s)
- Subash Dhakal
- Department of Bio and Fermentation Convergence Technology, Kookmin University, Seoul, 02707, Republic of Korea
| | - Jiun Sang
- Department of Bio and Fermentation Convergence Technology, Kookmin University, Seoul, 02707, Republic of Korea
| | - Binod Aryal
- Department of Bio and Fermentation Convergence Technology, Kookmin University, Seoul, 02707, Republic of Korea
| | - Youngseok Lee
- Department of Bio and Fermentation Convergence Technology, Kookmin University, Seoul, 02707, Republic of Korea.
- Interdisciplinary Program for Bio-Health Convergence, Kookmin University, Seoul, 02707, Republic of Korea.
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14
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Yang T, Yuan Z, Liu C, Liu T, Zhang W. A neural circuit integrates pharyngeal sensation to control feeding. Cell Rep 2021; 37:109983. [PMID: 34758309 DOI: 10.1016/j.celrep.2021.109983] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 08/20/2021] [Accepted: 10/20/2021] [Indexed: 11/18/2022] Open
Abstract
Swallowing is an essential step of eating and drinking. However, how the quality of a food bolus is sensed by pharyngeal neurons is largely unknown. Here we find that mechanical receptors along the Drosophila pharynx are required for control of meal size, especially for food of high viscosity. The mechanical force exerted by the bolus passing across the pharynx is detected by neurons expressing the mechanotransduction channel NOMPC (no mechanoreceptor potential C) and is relayed, together with gustatory information, to IN1 neurons in the subesophageal zone (SEZ) of the brain. IN1 (ingestion neurons) neurons act directly upstream of a group of peptidergic neurons that encode satiety. Prolonged activation of IN1 neurons suppresses feeding. IN1 neurons receive inhibition from DSOG1 (descending subesophageal neurons) neurons, a group of GABAergic neurons that non-selectively suppress feeding. Our results reveal the function of pharyngeal mechanoreceptors and their downstream neural circuits in the control of food ingestion.
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Affiliation(s)
- Tingting Yang
- School of Life Sciences, Tsinghua-Peking Joint Center for Life Sciences, IDG/McGovern Institute for Brain Research, Tsinghua University, Beijing 100084, China
| | - Zixuan Yuan
- School of Life Sciences, Tsinghua-Peking Joint Center for Life Sciences, IDG/McGovern Institute for Brain Research, Tsinghua University, Beijing 100084, China
| | - Chenxi Liu
- School of Life Sciences, Tsinghua-Peking Joint Center for Life Sciences, IDG/McGovern Institute for Brain Research, Tsinghua University, Beijing 100084, China
| | - Ting Liu
- School of Life Sciences, Tsinghua-Peking Joint Center for Life Sciences, IDG/McGovern Institute for Brain Research, Tsinghua University, Beijing 100084, China
| | - Wei Zhang
- School of Life Sciences, Tsinghua-Peking Joint Center for Life Sciences, IDG/McGovern Institute for Brain Research, Tsinghua University, Beijing 100084, China; Tsinghua-Peking Center for Life Sciences, Beijing 100084, China.
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15
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Expansion and application of dye tracers for measuring solid food intake and food preference in Drosophila. Sci Rep 2021; 11:20044. [PMID: 34625601 PMCID: PMC8501022 DOI: 10.1038/s41598-021-99483-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 09/23/2021] [Indexed: 12/03/2022] Open
Abstract
The Drosophila model is used to investigate the effects of diet on physiology as well as the effects of genetic pathways, neural systems and environment on feeding behavior. We previously showed that Blue 1 works well as a dye tracer to track consumption of agar-based media in Drosophila in a method called Con-Ex. Here, we describe Orange 4 as a novel dye for use in Con-Ex studies that expands the utility of this method. Con-Ex experiments using Orange 4 detect the predicted effects of starvation, mating status, strain, and sex on feeding behavior in flies. Orange 4 is consumed and excreted into vials linearly with time in Con-Ex experiments, the number of replicates required to detect differences between groups when using Orange 4 is comparable to that for Blue 1, and excretion of the dye reflects the volume of consumed dye. In food preference studies using Orange 4 and Blue 1 as a dye pair, flies decreased their intake of food laced with the aversive tastants caffeine and NaCl as determined using Con-Ex or a more recently described modification called EX-Q. Our results indicate that Orange 4 is suitable for Con-Ex experiments, has comparable utility to Blue 1 in Con-Ex studies, and can be paired with Blue 1 to assess food preference via both Con-Ex and EX-Q.
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16
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Abstract
Many animals rely on taste to identify nutritious foods and to avoid the consumption of harmful substances. The tastes of macronutrients, as well as of non-caloric micronutrients such as sodium and calcium, contribute to the regulation of ingestive behavior1,2. Whether vitamins also affect feeding behavior through taste is less clear. Here, we show that the fly Drosophila melanogaster has a strong preference for consuming a vitamin-containing diet: both sexes show a preference for folic acid, whereas only females show a preference for riboflavin. Females show a preference with vitamin concentrations as low as ∼10 nM - at least 50,000-fold lower than the concentration needed for sucrose preference. This female vitamin preference requires inputs from external and internal taste organs, suggesting that post-ingestive signals, in the absence of gustatory input, are insufficient to actuate preferential consumption of vitamin-containing diets. Our studies demonstrate that vitamin perception is an important determinant of feeding behavior.
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Affiliation(s)
- Qi Wu
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA; Center on Aging, The Scripps Research Institute, Jupiter, FL 33458, USA; Institute of Animal Genetics and Breeding, Sichuan Agricultural University, Chengdu, China
| | - Scarlet J Park
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA; Center on Aging, The Scripps Research Institute, Jupiter, FL 33458, USA; Skaggs Graduate School, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Mingyao Yang
- Institute of Animal Genetics and Breeding, Sichuan Agricultural University, Chengdu, China
| | - William W Ja
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA; Center on Aging, The Scripps Research Institute, Jupiter, FL 33458, USA; Skaggs Graduate School, The Scripps Research Institute, Jupiter, FL 33458, USA.
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17
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Chen YCD, Menon V, Joseph RM, Dahanukar AA. Control of Sugar and Amino Acid Feeding via Pharyngeal Taste Neurons. J Neurosci 2021; 41:5791-5808. [PMID: 34031164 PMCID: PMC8265808 DOI: 10.1523/jneurosci.1794-20.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 05/06/2021] [Accepted: 05/11/2021] [Indexed: 11/21/2022] Open
Abstract
Insect gustatory systems comprise multiple taste organs for detecting chemicals that signal palatable or noxious quality. Although much is known about how taste neurons sense various chemicals, many questions remain about how individual taste neurons in each taste organ control feeding. Here, we use the Drosophila pharynx as a model to investigate how taste information is encoded at the cellular level to regulate consumption of sugars and amino acids. We first generate taste-blind animals and establish a critical role for pharyngeal input in food selection. We then investigate feeding behavior of both male and female flies in which only selected classes of pharyngeal neurons are restored via binary choice feeding preference assays as well as Fly Liquid-Food Interaction Counter assays. We find instances of integration as well as redundancy in how pharyngeal neurons control behavioral responses to sugars and amino acids. Additionally, we find that pharyngeal neurons drive sugar feeding preference based on sweet taste but not on nutritional value. Finally, we demonstrate functional specialization of pharyngeal and external neurons using optogenetic activation. Overall, our genetic taste neuron protection system in a taste-blind background provides a powerful approach to elucidate principles of pharyngeal taste coding and demonstrates functional overlap and subdivision among taste neurons.SIGNIFICANCE STATEMENT Dietary intake of nutritious chemicals such as sugars and amino acids is essential for the survival of an animal. In insects, distinct classes of taste neurons control acceptance or rejection of food sources. Here, we develop a genetic system to investigate how individual taste neurons in the Drosophila pharynx encode specific tastants, focusing on sugars and amino acids. By examining flies in which only a single class of taste neurons is active, we find evidence for functional overlap as well as redundancy in responses to sugars and amino acids. We also uncover a functional subdivision between pharyngeal and external neurons in driving feeding responses. Overall, we find that different pharyngeal neurons act together to control intake of the two categories of appetitive tastants.
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Affiliation(s)
- Yu-Chieh David Chen
- Interdepartmental Neuroscience Program, University of California, Riverside, Riverside, California 92521
| | - Vaibhav Menon
- Interdepartmental Neuroscience Program, University of California, Riverside, Riverside, California 92521
| | - Ryan Matthew Joseph
- Department of Molecular, Cell, and Systems Biology, University of California, Riverside, Riverside, California 92521
| | - Anupama Arun Dahanukar
- Interdepartmental Neuroscience Program, University of California, Riverside, Riverside, California 92521
- Department of Molecular, Cell, and Systems Biology, University of California, Riverside, Riverside, California 92521
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18
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Ni L. The Structure and Function of Ionotropic Receptors in Drosophila. Front Mol Neurosci 2021; 13:638839. [PMID: 33597847 PMCID: PMC7882480 DOI: 10.3389/fnmol.2020.638839] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 12/28/2020] [Indexed: 12/21/2022] Open
Abstract
Ionotropic receptors (IRs) are a highly divergent subfamily of ionotropic glutamate receptors (iGluR) and are conserved across Protostomia, a major branch of the animal kingdom that encompasses both Ecdysozoa and Lophothrochozoa. They are broadly expressed in peripheral sensory systems, concentrated in sensory dendrites, and function in chemosensation, thermosensation, and hygrosensation. As iGluRs, four IR subunits form a functional ion channel to detect environmental stimuli. Most IR receptors comprise individual stimulus-specific tuning receptors and one or two broadly expressed coreceptors. This review summarizes the discoveries of the structure of IR complexes and the expression and function of each IR, as well as discusses the future direction for IR studies.
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Affiliation(s)
- Lina Ni
- School of Neuroscience, Virginia Tech, Blacksburg, VA, United States
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19
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Ni L. Genetic Transsynaptic Techniques for Mapping Neural Circuits in Drosophila. Front Neural Circuits 2021; 15:749586. [PMID: 34675781 PMCID: PMC8524129 DOI: 10.3389/fncir.2021.749586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 09/13/2021] [Indexed: 11/23/2022] Open
Abstract
A neural circuit is composed of a population of neurons that are interconnected by synapses and carry out a specific function when activated. It is the structural framework for all brain functions. Its impairments often cause diseases in the nervous system. To understand computations and functions in a brain circuit, it is of crucial importance to identify how neurons in this circuit are connected. Genetic transsynaptic techniques provide opportunities to efficiently answer this question. These techniques label synapses or across synapses to unbiasedly label synaptic partners. They allow for mapping neural circuits with high reproducibility and throughput, as well as provide genetic access to synaptically connected neurons that enables visualization and manipulation of these neurons simultaneously. This review focuses on three recently developed Drosophila genetic transsynaptic tools for detecting chemical synapses, highlights their advantages and potential pitfalls, and discusses the future development needs of these techniques.
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20
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Hubbard CB, Gerry AC. Selection, Reversion, and Characterization of House Fly (Diptera: Muscidae) Behavioral Resistance to the Insecticide Imidacloprid. JOURNAL OF MEDICAL ENTOMOLOGY 2020; 57:1843-1851. [PMID: 32516402 DOI: 10.1093/jme/tjaa105] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Indexed: 06/11/2023]
Abstract
Insecticide resistance in pest populations is an increasing problem in both urban and rural settings caused by over-application of insecticides and lack of rotation among chemical classes. The house fly (Musca domestica L.) is a cosmopolitan fly species implicated in the transmission of numerous pathogens, and which can be extremely pestiferous when present in high numbers. The evolution of insecticide resistance has long been documented in house flies, with resistance reported to all major insecticide classes. House fly resistance to imidacloprid, the most widely used neonicotinoid insecticide available for fly control, has been selected for in field populations through both physiological and behavioral resistance mechanisms. In the current study, house flies collected from a southern California dairy were selectively bred for behavioral resistance to imidacloprid, without increasing the physiological resistance profile of the selected flies. Flies were also successfully selected for behavioral susceptibility to imidacloprid. The rapid selection for either behavioral resistance or behavioral susceptibility suggests that inheritable alleles conferring behavioral resistance were already present in the wild-type fly population collected from the dairy site. The methods used for the specific selection of behavioral resistance (or susceptibility) in the fly population will be useful for further studies on the specific mechanisms conferring this resistance. House fly behavioral resistance was further investigated using behavioral observation and feeding preference assays, with resistance determined to be both contact-dependent and specific to the insecticide (imidacloprid) rather than to a non-insecticidal component of a bait matrix as previously documented.
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Affiliation(s)
| | - Alec C Gerry
- Department of Entomology, University of California, Riverside, CA
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21
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Muñoz IJ, Schilman PE, Barrozo RB. Impact of alkaloids in food consumption, metabolism and survival in a blood-sucking insect. Sci Rep 2020; 10:9443. [PMID: 32523008 PMCID: PMC7287067 DOI: 10.1038/s41598-020-65932-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 04/27/2020] [Indexed: 02/08/2023] Open
Abstract
The sense of taste provides information about the “good” or “bad” quality of a food source, which may be potentially nutritious or toxic. Most alkaloids taste bitter to humans, and because bitter taste is synonymous of noxious food, they are generally rejected. This response may be due to an innate low palatability or due to a malaise that occurs after food ingestion, which could even lead to death. We investigated in the kissing bug Rhodnius prolixus, whether alkaloids such as quinine, caffeine and theophylline, are merely distasteful, or if anti-appetitive responses are caused by a post-ingestion physiological effect, or both of these options. Although anti-appetitive responses were observed for the three alkaloids, only caffeine and theophylline affect metabolic and respiratory parameters that reflected an underlying physiological stress following their ingestion. Furthermore, caffeine caused the highest mortality. In contrast, quinine appears to be a merely unpalatable compound. The sense of taste helps insects to avoid making wrong feeding decisions, such as the intake of bitter/toxic foods, and thus avoid potentially harmful effects on health, a mechanism preserved in obligate hematophagous insects.
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Affiliation(s)
- Ignacio J Muñoz
- Grupo de Neuroetología de Insectos Vectores, Laboratorio Fisiología de Insectos, Instituto Biodiversidad Biología Experimental Aplicada, CONICET; Departamento Biodiversidad Biología Experimental, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, UBA, Buenos Aires, Argentina.,Laboratorio de Ecofisiología de Insectos, Instituto de Biodiversidad y Biología Experimental y Aplicada, CONICET; Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, UBA, Buenos Aires, Argentina
| | - Pablo E Schilman
- Laboratorio de Ecofisiología de Insectos, Instituto de Biodiversidad y Biología Experimental y Aplicada, CONICET; Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, UBA, Buenos Aires, Argentina.
| | - Romina B Barrozo
- Grupo de Neuroetología de Insectos Vectores, Laboratorio Fisiología de Insectos, Instituto Biodiversidad Biología Experimental Aplicada, CONICET; Departamento Biodiversidad Biología Experimental, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, UBA, Buenos Aires, Argentina.
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22
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Park SJ, Ja WW. Absolute ethanol intake predicts ethanol preference in Drosophilamelanogaster. J Exp Biol 2020; 223:jeb224121. [PMID: 32366685 PMCID: PMC7295594 DOI: 10.1242/jeb.224121] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 04/22/2020] [Indexed: 12/20/2022]
Abstract
Factors that mediate ethanol preference in Drosophila melanogaster are not well understood. A major confound has been the use of diverse methods to estimate ethanol consumption. We measured fly consumptive ethanol preference on base diets varying in nutrients, taste and ethanol concentration. Both sexes showed an ethanol preference that was abolished on high nutrient concentration diets. Additionally, manipulating total food intake without altering the nutritive value of the base diet or the ethanol concentration was sufficient to evoke or eliminate ethanol preference. Absolute ethanol intake and food volume consumed were stronger predictors of ethanol preference than caloric intake or the dietary caloric content. Our findings suggest that the effect of the base diet on ethanol preference is largely mediated by total consumption associated with the delivery medium, which ultimately determines the level of ethanol intake. We speculate that a physiologically relevant threshold for ethanol intake is essential for preferential ethanol consumption.
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Affiliation(s)
- Scarlet J Park
- Skaggs Graduate School, The Scripps Research Institute, Jupiter, FL 33458, USA
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - William W Ja
- Skaggs Graduate School, The Scripps Research Institute, Jupiter, FL 33458, USA
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
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23
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Wu Q, Yu G, Park SJ, Gao Y, Ja WW, Yang M. Excreta Quantification (EX-Q) for Longitudinal Measurements of Food Intake in Drosophila. iScience 2019; 23:100776. [PMID: 31901635 PMCID: PMC6941854 DOI: 10.1016/j.isci.2019.100776] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Revised: 11/28/2019] [Accepted: 12/12/2019] [Indexed: 12/20/2022] Open
Abstract
Longitudinal measurements of food intake remain a challenge in Drosophila studies of nutrition and behavior. Here, we report an improved method for measuring fly food intake using dye-labeled food and excreta quantification (EX-Q). Reducing the surface area of the medium maximized excreta recovery and the accuracy in estimating total consumption. The EX-Q method is compatible with agar-based medium and makes it possible to measure consumption over an extended period and at multiple time points without sacrificing flies. Using EX-Q, we revealed nutrient- and age-specific features of Drosophila feeding behavior. Daily consumption of a chemically defined diet was relatively consistent over the first 25 days of adulthood. Omitting amino acids or vitamins from the diet reduced consumption in both sexes, whereas omitting sugars or cholesterol primarily affected female food intake. Our results demonstrate EX-Q as a simple, reliable, and nondestructive method for longitudinal studies of solid food intake in Drosophila.
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Affiliation(s)
- Qi Wu
- Institute of Animal Genetics and Breeding, Sichuan Agricultural University, Chengdu, China
| | - Guixiang Yu
- Institute of Animal Genetics and Breeding, Sichuan Agricultural University, Chengdu, China
| | - Scarlet J Park
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA; Center on Aging, The Scripps Research Institute, Jupiter, FL 33458, USA; Skaggs Graduate School, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Yue Gao
- Institute of Animal Genetics and Breeding, Sichuan Agricultural University, Chengdu, China
| | - William W Ja
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA; Center on Aging, The Scripps Research Institute, Jupiter, FL 33458, USA; Skaggs Graduate School, The Scripps Research Institute, Jupiter, FL 33458, USA.
| | - Mingyao Yang
- Institute of Animal Genetics and Breeding, Sichuan Agricultural University, Chengdu, China.
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