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Wang Q, Smid HM, Dicke M, Haverkamp A. The olfactory system of Pieris brassicae caterpillars: from receptors to glomeruli. INSECT SCIENCE 2024; 31:469-488. [PMID: 38105530 DOI: 10.1111/1744-7917.13304] [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: 06/12/2023] [Revised: 10/17/2023] [Accepted: 10/30/2023] [Indexed: 12/19/2023]
Abstract
The olfactory system of adult lepidopterans is among the best described neuronal circuits. However, comparatively little is known about the organization of the olfactory system in the larval stage of these insects. Here, we explore the expression of olfactory receptors and the organization of olfactory sensory neurons in caterpillars of Pieris brassicae, a significant pest species in Europe and a well-studied species for its chemical ecology. To describe the larval olfactory system in this species, we first analyzed the head transcriptome of third-instar larvae (L3) and identified 16 odorant receptors (ORs) including the OR coreceptor (Orco), 13 ionotropic receptors (IRs), and 8 gustatory receptors (GRs). We then quantified the expression of these 16 ORs in different life stages, using qPCR, and found that the majority of ORs had significantly higher expression in the L4 stage than in the L3 and L5 stages, indicating that the larval olfactory system is not static throughout caterpillar development. Using an Orco-specific antibody, we identified all olfactory receptor neurons (ORNs) expressing the Orco protein in L3, L4, and L5 caterpillars and found a total of 34 Orco-positive ORNs, distributed among three sensilla on the antenna. The number of Orco-positive ORNs did not differ among the three larval instars. Finally, we used retrograde axon tracing of the antennal nerve and identified a mean of 15 glomeruli in the larval antennal center (LAC), suggesting that the caterpillar olfactory system follows a similar design as the adult olfactory system, although with a lower numerical redundancy. Taken together, our results provide a detailed analysis of the larval olfactory neurons in P. brassicae, highlighting both the differences as well as the commonalities with the adult olfactory system. These findings contribute to a better understanding of the development of the olfactory system in insects and its life-stage-specific adaptations.
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Affiliation(s)
- Qi Wang
- Laboratory of Entomology, Wageningen University and Research, Wageningen, the Netherlands
| | - Hans M Smid
- Laboratory of Entomology, Wageningen University and Research, Wageningen, the Netherlands
| | - Marcel Dicke
- Laboratory of Entomology, Wageningen University and Research, Wageningen, the Netherlands
| | - Alexander Haverkamp
- Laboratory of Entomology, Wageningen University and Research, Wageningen, the Netherlands
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2
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Couto A, Marty S, Dawson EH, d'Ettorre P, Sandoz JC, Montgomery SH. Evolution of the neuronal substrate for kin recognition in social Hymenoptera. Biol Rev Camb Philos Soc 2023; 98:2226-2242. [PMID: 37528574 DOI: 10.1111/brv.13003] [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: 08/11/2022] [Revised: 07/18/2023] [Accepted: 07/20/2023] [Indexed: 08/03/2023]
Abstract
In evolutionary terms, life is about reproduction. Yet, in some species, individuals forgo their own reproduction to support the reproductive efforts of others. Social insect colonies for example, can contain up to a million workers that actively cooperate in tasks such as foraging, brood care and nest defence, but do not produce offspring. In such societies the division of labour is pronounced, and reproduction is restricted to just one or a few individuals, most notably the queen(s). This extreme eusocial organisation exists in only a few mammals, crustaceans and insects, but strikingly, it evolved independently up to nine times in the order Hymenoptera (including ants, bees and wasps). Transitions from a solitary lifestyle to an organised society can occur through natural selection when helpers obtain a fitness benefit from cooperating with kin, owing to the indirect transmission of genes through siblings. However, this process, called kin selection, is vulnerable to parasitism and opportunistic behaviours from unrelated individuals. An ability to distinguish kin from non-kin, and to respond accordingly, could therefore critically facilitate the evolution of eusociality and the maintenance of non-reproductive workers. The question of how the hymenopteran brain has adapted to support this function is therefore a fundamental issue in evolutionary neuroethology. Early neuroanatomical investigations proposed that social Hymenoptera have expanded integrative brain areas due to selection for increased cognitive capabilities in the context of processing social information. Later studies challenged this assumption and instead pointed to an intimate link between higher social organisation and the existence of developed sensory structures involved in recognition and communication. In particular, chemical signalling of social identity, known to be mediated through cuticular hydrocarbons (CHCs), may have evolved hand in hand with a specialised chemosensory system in Hymenoptera. Here, we compile the current knowledge on this recognition system, from emitted identity signals, to the molecular and neuronal basis of chemical detection, with particular emphasis on its evolutionary history. Finally, we ask whether the evolution of social behaviour in Hymenoptera could have driven the expansion of their complex olfactory system, or whether the early origin and conservation of an olfactory subsystem dedicated to social recognition could explain the abundance of eusocial species in this insect order. Answering this question will require further comparative studies to provide a comprehensive view on lineage-specific adaptations in the olfactory pathway of Hymenoptera.
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Affiliation(s)
- Antoine Couto
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
- Evolution, Genomes, Behaviour and Ecology (UMR 9191), IDEEV, Université Paris-Saclay, CNRS, IRD, 12 route 128, Gif-sur-Yvette, 91190, France
| | - Simon Marty
- Evolution, Genomes, Behaviour and Ecology (UMR 9191), IDEEV, Université Paris-Saclay, CNRS, IRD, 12 route 128, Gif-sur-Yvette, 91190, France
| | - Erika H Dawson
- Laboratory of Experimental and Comparative Ethology, UR 4443 (LEEC), Université Sorbonne Paris Nord, 99 avenue J.-B. Clément, Villetaneuse, 93430, France
| | - Patrizia d'Ettorre
- Laboratory of Experimental and Comparative Ethology, UR 4443 (LEEC), Université Sorbonne Paris Nord, 99 avenue J.-B. Clément, Villetaneuse, 93430, France
- Institut Universitaire de France (IUF), 103 Boulevard Saint-Michel, Paris, 75005, France
| | - Jean-Christophe Sandoz
- Evolution, Genomes, Behaviour and Ecology (UMR 9191), IDEEV, Université Paris-Saclay, CNRS, IRD, 12 route 128, Gif-sur-Yvette, 91190, France
| | - Stephen H Montgomery
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
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3
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Depetris-Chauvin A, Galagovsky D, Keesey IW, Hansson BS, Sachse S, Knaden M. Evolution at multiple processing levels underlies odor-guided behavior in the genus Drosophila. Curr Biol 2023; 33:4771-4785.e7. [PMID: 37804828 DOI: 10.1016/j.cub.2023.09.039] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 08/02/2023] [Accepted: 09/15/2023] [Indexed: 10/09/2023]
Abstract
Olfaction is a fundamental sense guiding animals to their food. How the olfactory system evolves and influences behavior is still poorly understood. Here, we selected five drosophilid species, including Drosophila melanogaster, inhabiting different ecological niches to compare their olfactory systems at multiple levels. We first identified ecologically relevant natural food odorants from every species and established species-specific odorant preferences. To compare odor coding in sensory neurons, we analyzed the antennal lobe (AL) structure, generated glomerular atlases, and developed GCaMP transgenic lines for all species. Although subsets of glomeruli showed distinct tuning profiles, odorants inducing species-specific preferences were coded generally similarly. Species distantly related or occupying different habitats showed more evident differences in odor coding, and further analysis revealed that changes in olfactory receptor (OR) sequences partially explain these differences. Our results demonstrate that genetic distance in phylogeny and ecological niche occupancy are key determinants in the evolution of ORs, AL structures, odor coding, and behavior. Interestingly, changes in odor coding among species could not be explained by evolutionary changes at a single olfactory processing level but rather are a complex phenomenon based on changes at multiple levels.
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Affiliation(s)
- Ana Depetris-Chauvin
- Max Planck Institute for Chemical Ecology, Department of Evolutionary Neuroethology, 07745 Jena, Germany; Research Group Olfactory Coding, Max Planck Institute for Chemical Ecology, 07745 Jena, Germany
| | - Diego Galagovsky
- Max Planck Institute for Chemical Ecology, Department of Evolutionary Neuroethology, 07745 Jena, Germany
| | - Ian W Keesey
- Max Planck Institute for Chemical Ecology, Department of Evolutionary Neuroethology, 07745 Jena, Germany
| | - Bill S Hansson
- Max Planck Institute for Chemical Ecology, Department of Evolutionary Neuroethology, 07745 Jena, Germany
| | - Silke Sachse
- Research Group Olfactory Coding, Max Planck Institute for Chemical Ecology, 07745 Jena, Germany.
| | - Markus Knaden
- Max Planck Institute for Chemical Ecology, Department of Evolutionary Neuroethology, 07745 Jena, Germany.
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4
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Bandyopadhyay P, Sachse S. Mixing things up! - how odor blends are processed in Drosophila. CURRENT OPINION IN INSECT SCIENCE 2023; 59:101099. [PMID: 37562651 DOI: 10.1016/j.cois.2023.101099] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 07/26/2023] [Accepted: 08/02/2023] [Indexed: 08/12/2023]
Abstract
Insects have to navigate a complex and rich olfactory environment consisting of mixtures of odors at varying ratios. However, we understand little of how the olfactory system represents these complex blends. This review aims to highlight some of the recent results of studying this mixture code, in the Drosophila melanogaster olfactory system, as well as gives a short background to one of the most challenging questions in olfaction - how are mixtures encoded in the brain?
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Affiliation(s)
- Pramit Bandyopadhyay
- Research Group Olfactory Coding, Max Planck Institute for Chemical Ecology, Hans-Knoell-Str. 8, 07745 Jena, Germany
| | - Silke Sachse
- Research Group Olfactory Coding, Max Planck Institute for Chemical Ecology, Hans-Knoell-Str. 8, 07745 Jena, Germany.
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5
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Sizemore TR, Jonaitis J, Dacks AM. Heterogeneous receptor expression underlies non-uniform peptidergic modulation of olfaction in Drosophila. Nat Commun 2023; 14:5280. [PMID: 37644052 PMCID: PMC10465596 DOI: 10.1038/s41467-023-41012-3] [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: 02/02/2023] [Accepted: 08/21/2023] [Indexed: 08/31/2023] Open
Abstract
Sensory systems are dynamically adjusted according to the animal's ongoing needs by neuromodulators, such as neuropeptides. Neuropeptides are often widely-distributed throughout sensory networks, but it is unclear whether such neuropeptides uniformly modulate network activity. Here, we leverage the Drosophila antennal lobe (AL) to resolve whether myoinhibitory peptide (MIP) uniformly modulates AL processing. Despite being uniformly distributed across the AL, MIP decreases olfactory input to some glomeruli, while increasing olfactory input to other glomeruli. We reveal that a heterogeneous ensemble of local interneurons (LNs) are the sole source of AL MIP, and show that differential expression of the inhibitory MIP receptor across glomeruli allows MIP to act on distinct intraglomerular substrates. Our findings demonstrate how even a seemingly simple case of modulation can have complex consequences on network processing by acting non-uniformly within different components of the overall network.
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Affiliation(s)
- Tyler R Sizemore
- Department of Biology, Life Sciences Building, West Virginia University, Morgantown, WV, 26506, USA.
- Department of Molecular, Cellular, and Developmental Biology, Yale Science Building, Yale University, New Haven, CT, 06520-8103, USA.
| | - Julius Jonaitis
- Department of Biology, Life Sciences Building, West Virginia University, Morgantown, WV, 26506, USA
| | - Andrew M Dacks
- Department of Biology, Life Sciences Building, West Virginia University, Morgantown, WV, 26506, USA.
- Department of Neuroscience, West Virginia University, Morgantown, WV, 26506, USA.
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6
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Fabian B, Sachse S. Experience-dependent plasticity in the olfactory system of Drosophila melanogaster and other insects. Front Cell Neurosci 2023; 17:1130091. [PMID: 36923450 PMCID: PMC10010147 DOI: 10.3389/fncel.2023.1130091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 02/07/2023] [Indexed: 02/24/2023] Open
Abstract
It is long known that the nervous system of vertebrates can be shaped by internal and external factors. On the other hand, the nervous system of insects was long assumed to be stereotypic, although evidence for plasticity effects accumulated for several decades. To cover the topic comprehensively, this review recapitulates the establishment of the term "plasticity" in neuroscience and introduces its original meaning. We describe the basic composition of the insect olfactory system using Drosophila melanogaster as a representative example and outline experience-dependent plasticity effects observed in this part of the brain in a variety of insects, including hymenopterans, lepidopterans, locusts, and flies. In particular, we highlight recent advances in the study of experience-dependent plasticity effects in the olfactory system of D. melanogaster, as it is the most accessible olfactory system of all insect species due to the genetic tools available. The partly contradictory results demonstrate that morphological, physiological and behavioral changes in response to long-term olfactory stimulation are more complex than previously thought. Different molecular mechanisms leading to these changes were unveiled in the past and are likely responsible for this complexity. We discuss common problems in the study of experience-dependent plasticity, ways to overcome them, and future directions in this area of research. In addition, we critically examine the transferability of laboratory data to natural systems to address the topic as holistically as possible. As a mechanism that allows organisms to adapt to new environmental conditions, experience-dependent plasticity contributes to an animal's resilience and is therefore a crucial topic for future research, especially in an era of rapid environmental changes.
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Affiliation(s)
| | - Silke Sachse
- Research Group Olfactory Coding, Max Planck Institute for Chemical Ecology, Jena, Germany
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7
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Hayashi TT, MacKenzie AJ, Ganguly I, Ellis KE, Smihula HM, Jacob MS, Litwin-Kumar A, Caron SJC. Mushroom body input connections form independently of sensory activity in Drosophila melanogaster. Curr Biol 2022; 32:4000-4012.e5. [PMID: 35977547 PMCID: PMC9533768 DOI: 10.1016/j.cub.2022.07.055] [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: 11/05/2021] [Revised: 05/04/2022] [Accepted: 07/21/2022] [Indexed: 11/19/2022]
Abstract
Associative brain centers, such as the insect mushroom body, need to represent sensory information in an efficient manner. In Drosophila melanogaster, the Kenyon cells of the mushroom body integrate inputs from a random set of olfactory projection neurons, but some projection neurons-namely those activated by a few ethologically meaningful odors-connect to Kenyon cells more frequently than others. This biased and random connectivity pattern is conceivably advantageous, as it enables the mushroom body to represent a large number of odors as unique activity patterns while prioritizing the representation of a few specific odors. How this connectivity pattern is established remains largely unknown. Here, we test whether the mechanisms patterning the connections between Kenyon cells and projection neurons depend on sensory activity or whether they are hardwired. We mapped a large number of mushroom body input connections in partially anosmic flies-flies lacking the obligate odorant co-receptor Orco-and in wild-type flies. Statistical analyses of these datasets reveal that the random and biased connectivity pattern observed between Kenyon cells and projection neurons forms normally in the absence of most olfactory sensory activity. This finding supports the idea that even comparatively subtle, population-level patterns of neuronal connectivity can be encoded by fixed genetic programs and are likely to be the result of evolved prioritization of ecologically and ethologically salient stimuli.
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Affiliation(s)
- Tatsuya Tatz Hayashi
- School of Biological Sciences, University of Utah, Aline Skaggs Wilmot Biology Building, 257 South 1400 East, Salt Lake City, UT 84112, USA; Neuroscience Program, University of Utah, Salt Lake City, UT 84112, USA
| | - Alexander John MacKenzie
- School of Biological Sciences, University of Utah, Aline Skaggs Wilmot Biology Building, 257 South 1400 East, Salt Lake City, UT 84112, USA; Neuroscience Program, University of Utah, Salt Lake City, UT 84112, USA
| | - Ishani Ganguly
- Center for Theoretical Neuroscience, Columbia University, Jerome L Greene Science Center, 3227 Broadway, New York, NY 10027, USA
| | - Kaitlyn Elizabeth Ellis
- School of Biological Sciences, University of Utah, Aline Skaggs Wilmot Biology Building, 257 South 1400 East, Salt Lake City, UT 84112, USA
| | - Hayley Marie Smihula
- School of Biological Sciences, University of Utah, Aline Skaggs Wilmot Biology Building, 257 South 1400 East, Salt Lake City, UT 84112, USA
| | - Miles Solomon Jacob
- School of Biological Sciences, University of Utah, Aline Skaggs Wilmot Biology Building, 257 South 1400 East, Salt Lake City, UT 84112, USA
| | - Ashok Litwin-Kumar
- Center for Theoretical Neuroscience, Columbia University, Jerome L Greene Science Center, 3227 Broadway, New York, NY 10027, USA
| | - Sophie Jeanne Cécile Caron
- School of Biological Sciences, University of Utah, Aline Skaggs Wilmot Biology Building, 257 South 1400 East, Salt Lake City, UT 84112, USA; Neuroscience Program, University of Utah, Salt Lake City, UT 84112, USA.
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8
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Zhu KW, Burton SD, Nagai MH, Silverman JD, de March CA, Wachowiak M, Matsunami H. Decoding the olfactory map through targeted transcriptomics links murine olfactory receptors to glomeruli. Nat Commun 2022; 13:5137. [PMID: 36050313 PMCID: PMC9437035 DOI: 10.1038/s41467-022-32267-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 07/21/2022] [Indexed: 12/12/2022] Open
Abstract
Sensory processing in olfactory systems is organized across olfactory bulb glomeruli, wherein axons of peripheral sensory neurons expressing the same olfactory receptor co-terminate to transmit receptor-specific activity to central neurons. Understanding how receptors map to glomeruli is therefore critical to understanding olfaction. High-throughput spatial transcriptomics is a rapidly advancing field, but low-abundance olfactory receptor expression within glomeruli has previously precluded high-throughput mapping of receptors to glomeruli in the mouse. Here we combined sequential sectioning along the anteroposterior, dorsoventral, and mediolateral axes with target capture enrichment sequencing to overcome low-abundance target expression. This strategy allowed us to spatially map 86% of olfactory receptors across the olfactory bulb and uncover a relationship between OR sequence and glomerular position.
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Affiliation(s)
- Kevin W Zhu
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Shawn D Burton
- Department of Biological Sciences, Lehigh University, Bethlehem, PA, 18015, USA
- Department of Neurobiology, University of Utah School of Medicine, Salt Lake City, UT, 84112, USA
| | - Maira H Nagai
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Justin D Silverman
- College of Information Science and Technology, Pennsylvania State University, University Park, PA, 16802, USA
- Department of Statistics, Pennsylvania State University, University Park, PA, 16802, USA
- Department of Medicine, Pennsylvania State University, Hershey, PA, 17033, USA
- Institute for Computational and Data Science, Pennsylvania State University, University Park, PA, 16802, USA
| | - Claire A de March
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Matt Wachowiak
- Department of Neurobiology, University of Utah School of Medicine, Salt Lake City, UT, 84112, USA.
| | - Hiroaki Matsunami
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, 27710, USA.
- Department of Neurobiology, Duke University School of Medicine, Durham, NC, 27710, USA.
- Duke Institute for Brain Sciences, Duke University, Durham, NC, 27710, USA.
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9
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Herre M, Goldman OV, Lu TC, Caballero-Vidal G, Qi Y, Gilbert ZN, Gong Z, Morita T, Rahiel S, Ghaninia M, Ignell R, Matthews BJ, Li H, Vosshall LB, Younger MA. Non-canonical odor coding in the mosquito. Cell 2022; 185:3104-3123.e28. [PMID: 35985288 PMCID: PMC9480278 DOI: 10.1016/j.cell.2022.07.024] [Citation(s) in RCA: 56] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 01/05/2022] [Accepted: 07/20/2022] [Indexed: 12/23/2022]
Abstract
Aedes aegypti mosquitoes are a persistent human foe, transmitting arboviruses including dengue when they feed on human blood. Mosquitoes are intensely attracted to body odor and carbon dioxide, which they detect using ionotropic chemosensory receptors encoded by three large multi-gene families. Genetic mutations that disrupt the olfactory system have modest effects on human attraction, suggesting redundancy in odor coding. The canonical view is that olfactory sensory neurons each express a single chemosensory receptor that defines its ligand selectivity. We discovered that Ae. aegypti uses a different organizational principle, with many neurons co-expressing multiple chemosensory receptor genes. In vivo electrophysiology demonstrates that the broad ligand-sensitivity of mosquito olfactory neurons depends on this non-canonical co-expression. The redundancy afforded by an olfactory system in which neurons co-express multiple chemosensory receptors may increase the robustness of the mosquito olfactory system and explain our long-standing inability to disrupt the detection of humans by mosquitoes. Humans produce a complex blend of odor cues that attract female mosquitoes, and these cues are typically detected by olfactory neurons expressing a single receptor. In female Aedes aegypti mosquitos, however, many of these neurons co-express multiple chemosensory receptors directly affecting mosquito behavior and challenging the canonical one-receptor-to-one-neuron organization.
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Affiliation(s)
- Margaret Herre
- Laboratory of Neurogenetics and Behavior, The Rockefeller University, New York, NY 10065, USA; Kavli Neural Systems Institute, New York, NY 10065, USA; Weill Cornell/Rockefeller/Sloan Kettering Tri-Institutional MD-PhD Program, New York, NY 10065, USA
| | - Olivia V Goldman
- Laboratory of Neurogenetics and Behavior, The Rockefeller University, New York, NY 10065, USA; Kavli Neural Systems Institute, New York, NY 10065, USA
| | - Tzu-Chiao Lu
- Huffington Center on Aging and Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Gabriela Caballero-Vidal
- Disease Vector Group, Unit of Chemical Ecology, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp 234 22, Sweden
| | - Yanyan Qi
- Huffington Center on Aging and Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Zachary N Gilbert
- Laboratory of Neurogenetics and Behavior, The Rockefeller University, New York, NY 10065, USA
| | - Zhongyan Gong
- Laboratory of Neurogenetics and Behavior, The Rockefeller University, New York, NY 10065, USA
| | - Takeshi Morita
- Laboratory of Neurogenetics and Behavior, The Rockefeller University, New York, NY 10065, USA; Howard Hughes Medical Institute, New York, NY 10065, USA
| | - Saher Rahiel
- Laboratory of Neurogenetics and Behavior, The Rockefeller University, New York, NY 10065, USA
| | - Majid Ghaninia
- Disease Vector Group, Unit of Chemical Ecology, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp 234 22, Sweden
| | - Rickard Ignell
- Disease Vector Group, Unit of Chemical Ecology, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp 234 22, Sweden
| | - Benjamin J Matthews
- Laboratory of Neurogenetics and Behavior, The Rockefeller University, New York, NY 10065, USA; Howard Hughes Medical Institute, New York, NY 10065, USA
| | - Hongjie Li
- Huffington Center on Aging and Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Leslie B Vosshall
- Laboratory of Neurogenetics and Behavior, The Rockefeller University, New York, NY 10065, USA; Kavli Neural Systems Institute, New York, NY 10065, USA; Howard Hughes Medical Institute, New York, NY 10065, USA
| | - Meg A Younger
- Laboratory of Neurogenetics and Behavior, The Rockefeller University, New York, NY 10065, USA; Kavli Neural Systems Institute, New York, NY 10065, USA; Department of Biology, Boston University, Boston, MA 02215, USA.
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10
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Rihani K, Sachse S. Shedding Light on Inter-Individual Variability of Olfactory Circuits in Drosophila. Front Behav Neurosci 2022; 16:835680. [PMID: 35548690 PMCID: PMC9084309 DOI: 10.3389/fnbeh.2022.835680] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 03/29/2022] [Indexed: 12/25/2022] Open
Abstract
Inter-individual differences in behavioral responses, anatomy or functional properties of neuronal populations of animals having the same genotype were for a long time disregarded. The majority of behavioral studies were conducted at a group level, and usually the mean behavior of all individuals was considered. Similarly, in neurophysiological studies, data were pooled and normalized from several individuals. This approach is mostly suited to map and characterize stereotyped neuronal properties between individuals, but lacks the ability to depict inter-individual variability regarding neuronal wiring or physiological characteristics. Recent studies have shown that behavioral biases and preferences to olfactory stimuli can vary significantly among individuals of the same genotype. The origin and the benefit of these diverse “personalities” is still unclear and needs to be further investigated. A perspective taken into account the inter-individual differences is needed to explore the cellular mechanisms underlying this phenomenon. This review focuses on olfaction in the vinegar fly Drosophila melanogaster and summarizes previous and recent studies on odor-guided behavior and the underlying olfactory circuits in the light of inter-individual variability. We address the morphological and physiological variabilities present at each layer of the olfactory circuitry and attempt to link them to individual olfactory behavior. Additionally, we discuss the factors that might influence individuality with regard to olfactory perception.
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Affiliation(s)
- Karen Rihani
- Research Group Olfactory Coding, Max Planck Institute for Chemical Ecology, Jena, Germany
- Max Planck Center Next Generation Insect Chemical Ecology, Jena, Germany
| | - Silke Sachse
- Research Group Olfactory Coding, Max Planck Institute for Chemical Ecology, Jena, Germany
- Max Planck Center Next Generation Insect Chemical Ecology, Jena, Germany
- *Correspondence: Silke Sachse,
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11
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Borrero-Echeverry F, Solum M, Trona F, Becher PG, Wallin EA, Bengtsson M, Witzgall P, Lebreton S. The female sex pheromone (Z)-4-undecenal mediates flight attraction and courtship in Drosophila melanogaster. JOURNAL OF INSECT PHYSIOLOGY 2022; 137:104355. [PMID: 35007554 DOI: 10.1016/j.jinsphys.2022.104355] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 10/24/2021] [Accepted: 01/04/2022] [Indexed: 06/14/2023]
Abstract
Specific mate communication and recognition underlies reproduction and hence speciation. Our study provides new insights in Drosophila melanogaster premating olfactory communication. Mate communication evolves during adaptation to ecological niches and makes use of social signals and habitat cues. Female-produced, species-specific volatile pheromone (Z)-4-undecenal (Z4-11Al) and male pheromone (Z)-11-octadecenyl acetate (cVA) interact with food odour in a sex-specific manner. Furthermore, Z4-11Al, which mediates upwind flight attraction in both sexes, also elicits courtship in experienced males. Two isoforms of the olfactory receptor Or69a are co-expressed in the same olfactory sensory neurons. Z4-11Al is perceived via Or69aB, while the food odorant (R)-linalool is a main ligand for the other variant, Or69aA. However, only Z4-11Al mediates courtship in experienced males, not (R)-linalool. Behavioural discrimination is reflected by calcium imaging of the antennal lobe, showing distinct glomerular activation patterns by these two compounds. Male sex pheromone cVA is known to affect male and female courtship at close range, but does not elicit upwind flight attraction as a single compound, in contrast to Z4-11Al. A blend of the food odour vinegar and cVA attracted females, while a blend of vinegar and female pheromone Z4-11Al attracted males, instead. Sex-specific upwind flight attraction to blends of food volatiles and male and female pheromone, respectively, adds a new element to Drosophila olfactory premating communication and is an unambiguous paradigm for identifying the behaviourally active components, towards a more complete concept of food-pheromone odour objects.
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Affiliation(s)
- Felipe Borrero-Echeverry
- Chemical Ecology Unit, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, 230 53 Alnarp, Sweden; Corporación Colombiana de Investgación Agropecuaria, Agrosavia, Mosquera, Colombia
| | - Marit Solum
- Chemical Ecology Unit, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, 230 53 Alnarp, Sweden
| | - Federica Trona
- Chemical Ecology Unit, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, 230 53 Alnarp, Sweden
| | - Paul G Becher
- Chemical Ecology Unit, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, 230 53 Alnarp, Sweden
| | - Erika A Wallin
- Department of Chemical Engineering, Mid Sweden University, Holmgatan 10, 85170 Sundsvall, Sweden
| | - Marie Bengtsson
- Chemical Ecology Unit, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, 230 53 Alnarp, Sweden
| | - Peter Witzgall
- Chemical Ecology Unit, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, 230 53 Alnarp, Sweden.
| | - Sebastien Lebreton
- Chemical Ecology Unit, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, 230 53 Alnarp, Sweden; IRSEA, Research Institute for Semiochemistry and Applied Ethology, Quartier Salignan, 84400 Apt, France
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12
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Drosophila melanogaster Chemosensory Pathways as Potential Targets to Curb the Insect Menace. INSECTS 2022; 13:insects13020142. [PMID: 35206716 PMCID: PMC8874460 DOI: 10.3390/insects13020142] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 01/19/2022] [Accepted: 01/25/2022] [Indexed: 11/17/2022]
Abstract
Simple Summary The perception and processing of chemosensory stimuli are indispensable to the survival of living organisms. In insects, olfaction and gustation play a critical role in seeking food, finding mates and avoiding signs of danger. This review aims to present updated information about olfactory and gustatory signaling in the fruit fly Drosophila melanogaster. We have described the mechanisms involved in olfactory and gustatory perceptions at the molecular level, the receptors along with the allied molecules involved, and their signaling pathways in the fruit fly. Due to the magnifying problems of disease-causing insect vectors and crop pests, the applications of chemosensory signaling in controlling pests and insect vectors are also discussed. Abstract From a unicellular bacterium to a more complex human, smell and taste form an integral part of the basic sensory system. In fruit flies Drosophila melanogaster, the behavioral responses to odorants and tastants are simple, though quite sensitive, and robust. They explain the organization and elementary functioning of the chemosensory system. Molecular and functional analyses of the receptors and other critical molecules involved in olfaction and gustation are not yet completely understood. Hence, a better understanding of chemosensory cue-dependent fruit flies, playing a major role in deciphering the host-seeking behavior of pathogen transmitting insect vectors (mosquitoes, sandflies, ticks) and crop pests (Drosophila suzukii, Queensland fruit fly), is needed. Using D. melanogaster as a model organism, the knowledge gained may be implemented to design new means of controlling insects as well as in analyzing current batches of insect and pest repellents. In this review, the complete mechanisms of olfactory and gustatory perception, along with their implementation in controlling the global threat of disease-transmitting insect vectors and crop-damaging pests, are explained in fruit flies.
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Vulpe A, Kim HS, Ballou S, Wu ST, Grabe V, Nava Gonzales C, Liang T, Sachse S, Jeanne JM, Su CY, Menuz K. An ammonium transporter is a non-canonical olfactory receptor for ammonia. Curr Biol 2021; 31:3382-3390.e7. [PMID: 34111404 PMCID: PMC8355169 DOI: 10.1016/j.cub.2021.05.025] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 04/18/2021] [Accepted: 05/13/2021] [Indexed: 10/21/2022]
Abstract
Numerous hematophagous insects are attracted to ammonia, a volatile released in human sweat and breath.1-3 Low levels of ammonia also attract non-biting insects such as the genetic model organism Drosophila melanogaster and several species of agricultural pests.4,5 Two families of ligand-gated ion channels function as olfactory receptors in insects,6-10 and studies have linked ammonia sensitivity to a particular olfactory receptor in Drosophila.5,11,12 Given the widespread importance of ammonia to insect behavior, it is surprising that the genomes of most insects lack an ortholog of this gene.6 Here, we show that canonical olfactory receptors are not necessary for responses to ammonia in Drosophila. Instead, we demonstrate that a member of the ancient electrogenic ammonium transporter family, Amt, is likely a new type of olfactory receptor. We report two hitherto unidentified olfactory neuron populations that mediate neuronal and behavioral responses to ammonia in Drosophila. Their endogenous ammonia responses are lost in Amt mutant flies, and ectopic expression of either Drosophila or Anopheles Amt confers ammonia sensitivity. These results suggest that Amt is the first transporter known to function as an olfactory receptor in animals and that its function may be conserved across insect species.
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Affiliation(s)
- Alina Vulpe
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT 06269, USA
| | - Hyong S Kim
- Department of Neuroscience, Yale University, New Haven, CT 06510, USA
| | - Sydney Ballou
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT 06269, USA
| | - Shiuan-Tze Wu
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Veit Grabe
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Jena 07745, Germany
| | - Cesar Nava Gonzales
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Tiffany Liang
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT 06269, USA
| | - Silke Sachse
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Jena 07745, Germany
| | - James M Jeanne
- Department of Neuroscience, Yale University, New Haven, CT 06510, USA
| | - Chih-Ying Su
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Karen Menuz
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT 06269, USA; Connecticut Institute for Brain and Cognitive Sciences, University of Connecticut, Storrs, CT 06269, USA.
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14
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Large-scale characterization of sex pheromone communication systems in Drosophila. Nat Commun 2021; 12:4165. [PMID: 34230464 PMCID: PMC8260797 DOI: 10.1038/s41467-021-24395-z] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 06/11/2021] [Indexed: 11/08/2022] Open
Abstract
Insects use sex pheromones as a reproductive isolating mechanism to attract conspecifics and repel heterospecifics. Despite the profound knowledge of sex pheromones, little is known about the coevolutionary mechanisms and constraints on their production and detection. Using whole-genome sequences to infer the kinship among 99 drosophilids, we investigate how phylogenetic and chemical traits have interacted at a wide evolutionary timescale. Through a series of chemical syntheses and electrophysiological recordings, we identify 52 sex-specific compounds, many of which are detected via olfaction. Behavioral analyses reveal that many of the 43 male-specific compounds are transferred to the female during copulation and mediate female receptivity and/or male courtship inhibition. Measurement of phylogenetic signals demonstrates that sex pheromones and their cognate olfactory channels evolve rapidly and independently over evolutionary time to guarantee efficient intra- and inter-specific communication systems. Our results show how sexual isolation barriers between species can be reinforced by species-specific olfactory signals. Despite the profound knowledge of sex pheromones, little is known about the coevolutionary mechanisms and constraints on their production and detection. Whole-genome sequences from 99 drosophilids, with chemical and behavioural data, show that sex pheromones and their cognate olfactory channels evolve rapidly and independently.
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15
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Tait C, Kharva H, Schubert M, Kritsch D, Sombke A, Rybak J, Feder JL, Olsson SB. A reversal in sensory processing accompanies ongoing ecological divergence and speciation in Rhagoletis pomonella. Proc Biol Sci 2021; 288:20210192. [PMID: 33757346 DOI: 10.1098/rspb.2021.0192] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Changes in behaviour often drive rapid adaptive evolution and speciation. However, the mechanistic basis for behavioural shifts is largely unknown. The tephritid fruit fly Rhagoletis pomonella is an example of ecological specialization and speciation in action via a recent host plant shift from hawthorn to apple. These flies primarily use specific odours to locate fruit, and because they mate only on or near host fruit, changes in odour preference for apples versus hawthorns translate directly to prezygotic reproductive isolation, initiating speciation. Using a variety of techniques, we found a reversal between apple and hawthorn flies in the sensory processing of key odours associated with host fruit preference at the first olfactory synapse, linking changes in the antennal lobe of the brain with ongoing ecological divergence. Indeed, changes to specific neural pathways of any sensory modality may be a broad mechanism for changes in animal behaviour, catalysing the genesis of new biodiversity.
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Affiliation(s)
- Cheyenne Tait
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Hinal Kharva
- Naturalist-Inspired Chemical Ecology, National Centre for Biological Sciences, Tata Institute of Fundamental Research, GKVK Campus, Bellary Road, Bangalore 560065, India.,School of Life Sciences, The University of Trans-Disciplinary Health Sciences and Technology, 74/2, Jarakabande Kaval, Post Attur via Yelahanka, Bangalore 560064, India
| | - Marco Schubert
- Department of Biology, Chemistry and Pharmacy, Institute of Biology, Free University Berlin, Berlin 14195, Germany
| | - Daniel Kritsch
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Hans Knöll Strasse 8, Jena 07745, Germany
| | - Andy Sombke
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Hans Knöll Strasse 8, Jena 07745, Germany
| | - Jürgen Rybak
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Hans Knöll Strasse 8, Jena 07745, Germany
| | - Jeffrey L Feder
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Shannon B Olsson
- Naturalist-Inspired Chemical Ecology, National Centre for Biological Sciences, Tata Institute of Fundamental Research, GKVK Campus, Bellary Road, Bangalore 560065, India
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16
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Baltruschat L, Prisco L, Ranft P, Lauritzen JS, Fiala A, Bock DD, Tavosanis G. Circuit reorganization in the Drosophila mushroom body calyx accompanies memory consolidation. Cell Rep 2021; 34:108871. [PMID: 33730583 DOI: 10.1016/j.celrep.2021.108871] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 01/07/2021] [Accepted: 02/24/2021] [Indexed: 12/21/2022] Open
Abstract
The formation and consolidation of memories are complex phenomena involving synaptic plasticity, microcircuit reorganization, and the formation of multiple representations within distinct circuits. To gain insight into the structural aspects of memory consolidation, we focus on the calyx of the Drosophila mushroom body. In this essential center, essential for olfactory learning, second- and third-order neurons connect through large synaptic microglomeruli, which we dissect at the electron microscopy level. Focusing on microglomeruli that respond to a specific odor, we reveal that appetitive long-term memory results in increased numbers of precisely those functional microglomeruli responding to the conditioned odor. Hindering memory consolidation by non-coincident presentation of odor and reward, by blocking protein synthesis, or by including memory mutants suppress these structural changes, revealing their tight correlation with the process of memory consolidation. Thus, olfactory long-term memory is associated with input-specific structural modifications in a high-order center of the fly brain.
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Affiliation(s)
| | - Luigi Prisco
- Center for Neurodegenerative Diseases (DZNE), 53175 Bonn, Germany
| | - Philipp Ranft
- Center for Neurodegenerative Diseases (DZNE), 53175 Bonn, Germany
| | - J Scott Lauritzen
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - André Fiala
- Molecular Neurobiology of Behaviour, University of Göttingen, 37077 Göttingen, Germany
| | - Davi D Bock
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA; Department of Neurological Sciences, University of Vermont, Burlington, VT 05405, USA
| | - Gaia Tavosanis
- Center for Neurodegenerative Diseases (DZNE), 53175 Bonn, Germany; LIMES Institute, University of Bonn, 53115 Bonn, Germany.
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17
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Scaplen KM, Talay M, Fisher JD, Cohn R, Sorkaç A, Aso Y, Barnea G, Kaun KR. Transsynaptic mapping of Drosophila mushroom body output neurons. eLife 2021; 10:e63379. [PMID: 33570489 PMCID: PMC7877909 DOI: 10.7554/elife.63379] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 01/26/2021] [Indexed: 11/13/2022] Open
Abstract
The mushroom body (MB) is a well-characterized associative memory structure within the Drosophila brain. Analyzing MB connectivity using multiple approaches is critical for understanding the functional implications of this structure. Using the genetic anterograde transsynaptic tracing tool, trans-Tango, we identified divergent projections across the brain and convergent downstream targets of the MB output neurons (MBONs). Our analysis revealed at least three separate targets that receive convergent input from MBONs: other MBONs, the fan-shaped body (FSB), and the lateral accessory lobe (LAL). We describe, both anatomically and functionally, a multilayer circuit in which inhibitory and excitatory MBONs converge on the same genetic subset of FSB and LAL neurons. This circuit architecture enables the brain to update and integrate information with previous experience before executing appropriate behavioral responses. Our use of trans-Tango provides a genetically accessible anatomical framework for investigating the functional relevance of components within these complex and interconnected circuits.
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Affiliation(s)
- Kristin M Scaplen
- Department of Neuroscience, Brown UniversityProvidenceUnited States
- Department of Psychology, Bryant UniversitySmithfieldUnited States
- Center for Health and Behavioral Sciences, Bryant UniversitySmithfieldUnited States
| | - Mustafa Talay
- Department of Neuroscience, Brown UniversityProvidenceUnited States
| | - John D Fisher
- Department of Neuroscience, Brown UniversityProvidenceUnited States
| | - Raphael Cohn
- Laboratory of Neurophysiology and Behavior, The Rockefeller UniversityNew YorkUnited States
| | - Altar Sorkaç
- Department of Neuroscience, Brown UniversityProvidenceUnited States
| | - Yoshi Aso
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Gilad Barnea
- Department of Neuroscience, Brown UniversityProvidenceUnited States
| | - Karla R Kaun
- Department of Neuroscience, Brown UniversityProvidenceUnited States
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18
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Das Chakraborty S, Sachse S. Olfactory processing in the lateral horn of Drosophila. Cell Tissue Res 2021; 383:113-123. [PMID: 33475851 PMCID: PMC7873099 DOI: 10.1007/s00441-020-03392-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 12/10/2020] [Indexed: 11/24/2022]
Abstract
Sensing olfactory signals in the environment represents a crucial and significant task of sensory systems in almost all organisms to facilitate survival and reproduction. Notably, the olfactory system of diverse animal phyla shares astonishingly many fundamental principles with regard to anatomical and functional properties. Binding of odor ligands by chemosensory receptors present in the olfactory peripheral organs leads to a neuronal activity that is conveyed to first and higher-order brain centers leading to a subsequent odor-guided behavioral decision. One of the key centers for integrating and processing innate olfactory behavior is the lateral horn (LH) of the protocerebrum in insects. In recent years the LH of Drosophila has garnered increasing attention and many studies have been dedicated to elucidate its circuitry. In this review we will summarize the recent advances in mapping and characterizing LH-specific cell types, their functional properties with respect to odor tuning, their neurotransmitter profiles, their connectivity to pre-synaptic and post-synaptic partner neurons as well as their impact for olfactory behavior as known so far.
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Affiliation(s)
- Sudeshna Das Chakraborty
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Hans-Knoell-Str. 8, 07745, Jena, Germany
| | - Silke Sachse
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Hans-Knoell-Str. 8, 07745, Jena, Germany.
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19
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An updated antennal lobe atlas for the yellow fever mosquito Aedes aegypti. PLoS Negl Trop Dis 2020; 14:e0008729. [PMID: 33079925 PMCID: PMC7575095 DOI: 10.1371/journal.pntd.0008729] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 08/17/2020] [Indexed: 12/17/2022] Open
Abstract
The yellow fever mosquito Aedes aegypti is a prolific vector of arboviral and filarial diseases that largely relies on its sense of smell to find humans. To facilitate in-depth analysis of the neural circuitry underlying Ae. aegypti olfactory-driven behaviors, we generated an updated in vitro atlas for the antennal lobe olfactory brain region of this disease vector using two independent neuronal staining methods. We performed morphological reconstructions with replicate fixed, dissected and stained brain samples from adult male and female Ae. aegypti of the LVPib12 genome reference strain and determined that the antennal lobe in both sexes is comprised of approximately 80 discrete glomeruli. Guided by landmark features in the antennal lobe, we found 63 of these glomeruli are stereotypically located in spatially invariant positions within these in vitro preparations. A posteriorly positioned, mediodorsal glomerulus denoted MD1 was identified as the largest spatially invariant glomerulus in the antennal lobe. Spatial organization of glomeruli in a recently field-derived strain of Ae. aegypti from Puerto Rico was conserved, despite differences in antennal lobe shape relative to the inbred LVPib12 strain. This model in vitro atlas will serve as a useful community resource to improve antennal lobe annotation and anatomically map projection patterns of neurons expressing target genes in this olfactory center. It will also facilitate the development of chemotopic maps of odor representation in the mosquito antennal lobe to decode the molecular and cellular basis of Ae. aegypti attraction to human scent and other chemosensory cues. The olfactory system of the yellow fever mosquito Aedes aegypti is highly tuned for the detection of human odorants, as well as other chemical cues influencing host and food-search behavior, egg-laying and mating. To provide insights into the neuroanatomical organization of the olfactory system of this globally important disease vector, we have generated an updated in vitro atlas for the primary smell processing center of the Ae. aegypti brain, called the antennal lobe. These new guide maps facilitate systematic interrogation of antennal lobe morphology and naming of associated substructures in dissected brain samples of this species labeled with two common neural staining methods. We report that landmark features of the Ae. aegypti antennal lobe morphology and spatial organization appear conserved between mosquito sexes and across geographically divergent strains of this mosquito species. An improved understanding of Ae. aegypti antennal lobe neuroanatomy and how attractive or repellent odorant stimuli are encoded in this brain center has the potential to rapidly accelerate reverse engineering of synthetic chemical blends that effectively lure, confuse or repel this major disease vector.
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20
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Muscarinic Modulation of Antennal Lobe GABAergic Local Neurons Shapes Odor Coding and Behavior. Cell Rep 2020; 29:3253-3265.e4. [PMID: 31801087 PMCID: PMC6900217 DOI: 10.1016/j.celrep.2019.10.125] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 09/18/2019] [Accepted: 10/29/2019] [Indexed: 11/21/2022] Open
Abstract
In the antennal lobe (AL), the first olfactory relay of Drosophila, excitatory neurons are predominantly cholinergic. Ionotropic nicotinic receptors play a vital role in the effects of acetylcholine in the AL. However, the AL also has a high expression level of metabotropic muscarinic acetylcholine receptors type A (mAChRs-A). Nevertheless, the neurons expressing them and their role in the AL are unknown. Elucidating their function may reveal principles in olfactory modulation. Here, we show that mAChRs-A shape AL output and affect behavior. We localized mAChRs-A effects to a sub-population of GABAergic local neurons (iLNs), where they play a dual role: direct excitation of iLNs and stabilization of the synapse between receptor neurons and iLNs, which undergoes strong short-term depression. Our results reveal modulatory functions of the AL main excitatory neurotransmitter. Striking similarities to the mammalian olfactory system predict that mammalian glutamatergic metabotropic receptors could be associated with similar modulations.
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21
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Gonzalez F, Borrero‐Echeverry F, Jósvai JK, Strandh M, Unelius CR, Tóth M, Witzgall P, Bengtsson M, Walker WB. Odorant receptor phylogeny confirms conserved channels for sex pheromone and host plant signals in tortricid moths. Ecol Evol 2020; 10:7334-7348. [PMID: 32760532 PMCID: PMC7391548 DOI: 10.1002/ece3.6458] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 05/08/2020] [Accepted: 05/12/2020] [Indexed: 11/09/2022] Open
Abstract
The search for mates and food is mediated by volatile chemicals. Insects sense food odorants and sex pheromones through odorant receptors (ORs) and pheromone receptors (PRs), which are expressed in olfactory sensory neurons. Molecular phylogenetics of ORs, informed by behavioral and functional data, generates sound hypotheses for the identification of semiochemicals driving olfactory behavior. Studying orthologous receptors and their ligands across taxa affords insights into the role of chemical communication in reproductive isolation and phylogenetic divergence. The female sex pheromone of green budworm moth Hedya nubiferana (Lepidoptera, Totricidae) is a blend of two unsaturated acetates, only a blend of both elicits male attraction. Females produce in addition codlemone, which is the sex pheromone of another tortricid, codling moth Cydia pomonella. Codlemone also attracts green budworm moth males. Concomitantly, green budworm and codling moth males are attracted to the host plant volatile pear ester. A congruent behavioral response to the same pheromone and plant volatile in two tortricid species suggests co-occurrence of dedicated olfactory channels. In codling moth, one PR is tuned to both compounds, the sex pheromone codlemone and the plant volatile pear ester. Our phylogenetic analysis finds that green budworm moth expresses an orthologous PR gene. Shared ancestry, and high levels of amino acid identity and sequence similarity, in codling and green budworm moth PRs offer an explanation for parallel attraction of both species to the same compounds. A conserved olfactory channel for a sex pheromone and a host plant volatile substantiates the alliance of social and habitat signals in insect chemical communication. Field attraction assays confirm that in silico investigations of ORs afford powerful predictions for an efficient identification of behavior-modifying semiochemicals, for an improved understanding of the mechanisms of host plant attraction in insect herbivores and for the further development of sustainable insect control.
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Affiliation(s)
- Francisco Gonzalez
- Department to Plant Protection BiologySwedish University of Agricultural SciencesAlnarpSweden
- ChemTica InternacionalHerediaCosta Rica
| | - Felipe Borrero‐Echeverry
- Department to Plant Protection BiologySwedish University of Agricultural SciencesAlnarpSweden
- Corporación Colombiana de Investgación AgropecuariaAgrosaviaMosqueraColombia
| | | | - Maria Strandh
- Department to Plant Protection BiologySwedish University of Agricultural SciencesAlnarpSweden
- Molecular Ecology and Evolution LabDepartment of BiologyLund UniversityLundSweden
| | | | - Miklós Tóth
- Plant Protection Institute CARBudapestHungary
| | - Peter Witzgall
- Department to Plant Protection BiologySwedish University of Agricultural SciencesAlnarpSweden
| | - Marie Bengtsson
- Department to Plant Protection BiologySwedish University of Agricultural SciencesAlnarpSweden
| | - William B. Walker
- Department to Plant Protection BiologySwedish University of Agricultural SciencesAlnarpSweden
- Faculty of Forestry and Wood SciencesCzech University of Life SciencesPragueCzech Republic
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22
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Khallaf MA, Auer TO, Grabe V, Depetris-Chauvin A, Ammagarahalli B, Zhang DD, Lavista-Llanos S, Kaftan F, Weißflog J, Matzkin LM, Rollmann SM, Löfstedt C, Svatoš A, Dweck HKM, Sachse S, Benton R, Hansson BS, Knaden M. Mate discrimination among subspecies through a conserved olfactory pathway. SCIENCE ADVANCES 2020; 6:eaba5279. [PMID: 32704542 PMCID: PMC7360436 DOI: 10.1126/sciadv.aba5279] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 05/07/2020] [Indexed: 05/22/2023]
Abstract
Communication mechanisms underlying the sexual isolation of species are poorly understood. Using four subspecies of Drosophila mojavensis as a model, we identify two behaviorally active, male-specific pheromones. One functions as a conserved male antiaphrodisiac in all subspecies and acts via gustation. The second induces female receptivity via olfaction exclusively in the two subspecies that produce it. Genetic analysis of the cognate receptor for the olfactory pheromone indicates an important role for this sensory pathway in promoting sexual isolation of subspecies, in combination with auditory signals. Unexpectedly, the peripheral sensory pathway detecting this pheromone is conserved molecularly, physiologically, and anatomically across subspecies. These observations imply that subspecies-specific behaviors arise from differential interpretation of the same peripheral cue, reminiscent of sexually conserved detection but dimorphic interpretation of male pheromones in Drosophila melanogaster. Our results reveal that, during incipient speciation, pheromone production, detection, and interpretation do not necessarily evolve in a coordinated manner.
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Affiliation(s)
- Mohammed A. Khallaf
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, D-07745 Jena, Germany
| | - Thomas O. Auer
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Veit Grabe
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, D-07745 Jena, Germany
| | - Ana Depetris-Chauvin
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, D-07745 Jena, Germany
| | - Byrappa Ammagarahalli
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221, USA
| | - Dan-Dan Zhang
- Department of Biology, Lund University, SE-22362 Lund, Sweden
| | - Sofía Lavista-Llanos
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, D-07745 Jena, Germany
| | - Filip Kaftan
- Group of Mass Spectrometry and Proteomics, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, D-07745 Jena, Germany
| | - Jerrit Weißflog
- Group of Mass Spectrometry and Proteomics, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, D-07745 Jena, Germany
| | - Luciano M. Matzkin
- Department of Entomology, University of Arizona, 1140 E. South Campus Drive, Tucson, AZ 85721, USA
| | - Stephanie M. Rollmann
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221, USA
| | | | - Aleš Svatoš
- Group of Mass Spectrometry and Proteomics, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, D-07745 Jena, Germany
| | - Hany K. M. Dweck
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, D-07745 Jena, Germany
| | - Silke Sachse
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, D-07745 Jena, Germany
| | - Richard Benton
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Bill S. Hansson
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, D-07745 Jena, Germany
| | - Markus Knaden
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, D-07745 Jena, Germany
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23
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Multiple network properties overcome random connectivity to enable stereotypic sensory responses. Nat Commun 2020; 11:1023. [PMID: 32094345 PMCID: PMC7039968 DOI: 10.1038/s41467-020-14836-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 02/03/2020] [Indexed: 02/08/2023] Open
Abstract
Connections between neuronal populations may be genetically hardwired or random. In the insect olfactory system, projection neurons of the antennal lobe connect randomly to Kenyon cells of the mushroom body. Consequently, while the odor responses of the projection neurons are stereotyped across individuals, the responses of the Kenyon cells are variable. Surprisingly, downstream of Kenyon cells, mushroom body output neurons show stereotypy in their responses. We found that the stereotypy is enabled by the convergence of inputs from many Kenyon cells onto an output neuron, and does not require learning. The stereotypy emerges in the total response of the Kenyon cell population using multiple odor-specific features of the projection neuron responses, benefits from the nonlinearity in the transfer function, depends on the convergence:randomness ratio, and is constrained by sparseness. Together, our results reveal the fundamental mechanisms and constraints with which convergence enables stereotypy in sensory responses despite random connectivity.
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24
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Paoli M, Nishino H, Couzin-Fuchs E, Galizia CG. Coding of odour and space in the hemimetabolous insect Periplaneta americana. J Exp Biol 2020; 223:jeb218032. [PMID: 31932303 DOI: 10.1242/jeb.218032] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 01/06/2020] [Indexed: 11/20/2022]
Abstract
The general architecture of the olfactory system is highly conserved from insects to humans, but neuroanatomical and physiological differences can be observed across species. The American cockroach, inhabiting dark shelters with a rather stable olfactory landscape, is equipped with long antennae used for sampling the surrounding air-space for orientation and navigation. The antennae's exceptional length provides a wide spatial working range for odour detection; however, it is still largely unknown whether and how this is also used for mapping the structure of the olfactory environment. By selectively labelling antennal lobe projection neurons with a calcium-sensitive dye, we investigated the logic of olfactory coding in this hemimetabolous insect. We show that odour responses are stimulus specific and concentration dependent, and that structurally related odorants evoke physiologically similar responses. By using spatially confined stimuli, we show that proximal stimulations induce stronger and faster responses than distal ones. Spatially confined stimuli of the female pheromone periplanone B activate a subregion of the male macroglomerulus. Thus, we report that the combinatorial logic of odour coding deduced from holometabolous insects applies also to this hemimetabolous species. Furthermore, a fast decrease in sensitivity along the antenna, not supported by a proportionate decrease in sensillar density, suggests a neural architecture that strongly emphasizes neuronal inputs from the proximal portion of the antenna.
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Affiliation(s)
- Marco Paoli
- Department of Neuroscience, University of Konstanz, 78457 Konstanz, Germany
| | - Hiroshi Nishino
- Research Institute for Electronic Science, Hokkaido University, Sapporo 060-0812, Japan
| | - Einat Couzin-Fuchs
- Department of Neuroscience, University of Konstanz, 78457 Konstanz, Germany
| | - C Giovanni Galizia
- Department of Neuroscience, University of Konstanz, 78457 Konstanz, Germany
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25
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Odor-Induced Multi-Level Inhibitory Maps in Drosophila. eNeuro 2020; 7:ENEURO.0213-19.2019. [PMID: 31888962 PMCID: PMC6957311 DOI: 10.1523/eneuro.0213-19.2019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 12/06/2019] [Accepted: 12/16/2019] [Indexed: 12/04/2022] Open
Abstract
Optical imaging of intracellular Ca2+ influx as a correlate of neuronal excitation represents a standard technique for visualizing spatiotemporal activity of neuronal networks. However, the information-processing properties of single neurons and neuronal circuits likewise involve inhibition of neuronal membrane potential. Here, we report spatially resolved optical imaging of odor-evoked inhibitory patterns in the olfactory circuitry of Drosophila using a genetically encoded fluorescent Cl- sensor. In combination with the excitatory component reflected by intracellular Ca2+ dynamics, we present a comprehensive functional map of both odor-evoked neuronal activation and inhibition at different levels of olfactory processing. We demonstrate that odor-evoked inhibition carried by Cl- influx is present both in sensory neurons and second-order projection neurons (PNs), and is characterized by stereotypic, odor-specific patterns. Cl--mediated inhibition features distinct dynamics in different neuronal populations. Our data support a dual role of inhibitory neurons in the olfactory system: global gain control across the neuronal circuitry and glomerulus-specific inhibition to enhance neuronal information processing.
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26
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Abstract
The brain's synaptic networks endow an animal with powerfully adaptive biological behavior. Maps of such synaptic circuits densely reconstructed in those model brains that can be examined and manipulated by genetic means offer the best prospect for understanding the underlying biological bases of behavior. That prospect is now technologically feasible and a scientifically enabling possibility in neurobiology, much as genomics has been in molecular biology and genetics. In Drosophila, two major advances are in electron microscopic technology, using focused ion beam-scanning electron microscopy (FIB-SEM) milling to capture and align digital images, and in computer-aided reconstruction of neuron morphologies. The last decade has witnessed enormous progress in detailed knowledge of the actual synaptic circuits formed by real neurons. Advances in various brain regions that heralded identification of the motion-sensing circuits in the optic lobe are now extending to other brain regions, with the prospect of encompassing the fly's entire nervous system, both brain and ventral nerve cord.
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Affiliation(s)
- Louis K Scheffer
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia 20147-2408, USA;
| | - Ian A Meinertzhagen
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia 20147-2408, USA; .,Department of Psychology and Neuroscience and Department of Biology, Life Sciences Centre, Dalhousie University, Halifax, Canada B3H 4R2
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27
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Groothuis J, Pfeiffer K, El Jundi B, Smid HM. The Jewel Wasp Standard Brain: Average shape atlas and morphology of the female Nasonia vitripennis brain. ARTHROPOD STRUCTURE & DEVELOPMENT 2019; 51:41-51. [PMID: 31357033 DOI: 10.1016/j.asd.2019.100878] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 07/25/2019] [Accepted: 07/25/2019] [Indexed: 06/10/2023]
Abstract
Nasonia, a genus of parasitoid wasps, is a promising model system in the study of developmental and evolutionary genetics, as well as complex traits such as learning. Of these "jewel wasps", the species Nasonia vitripennis is widely spread and widely studied. To accelerate neuroscientific research in this model species, fundamental knowledge of its nervous system is needed. To this end, we present an average standard brain of recently eclosed naïve female N. vitripennis wasps obtained by the iterative shape averaging method. This "Jewel Wasp Standard Brain" includes the optic lobe (excluding the lamina), the anterior optic tubercle, the antennal lobe, the lateral horn, the mushroom body, the central complex, and the remaining unclassified neuropils in the central brain. Furthermore, we briefly describe these well-defined neuropils and their subregions in the N. vitripennis brain. A volumetric analysis of these neuropils is discussed in the context of brains of other insect species. The Jewel Wasp Standard Brain will provide a framework to integrate and consolidate the results of future neurobiological studies in N. vitripennis. In addition, the volumetric analysis provides a baseline for future work on age- and experience-dependent brain plasticity.
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Affiliation(s)
- Jitte Groothuis
- Laboratory of Entomology, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, the Netherlands
| | - Keram Pfeiffer
- Behavioral Physiology and Sociobiology (Zoology II), University of Würzburg, Biocenter, Am Hubland, 97074, Würzburg, Germany
| | - Basil El Jundi
- Behavioral Physiology and Sociobiology (Zoology II), University of Würzburg, Biocenter, Am Hubland, 97074, Würzburg, Germany
| | - Hans M Smid
- Laboratory of Entomology, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, the Netherlands.
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28
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Martelli C, Fiala A. Slow presynaptic mechanisms that mediate adaptation in the olfactory pathway of Drosophila. eLife 2019; 8:43735. [PMID: 31169499 PMCID: PMC6581506 DOI: 10.7554/elife.43735] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Accepted: 06/05/2019] [Indexed: 12/14/2022] Open
Abstract
The olfactory system encodes odor stimuli as combinatorial activity of populations of neurons whose response depends on stimulus history. How and on which timescales previous stimuli affect these combinatorial representations remains unclear. We use in vivo optical imaging in Drosophila to analyze sensory adaptation at the first synaptic step along the olfactory pathway. We show that calcium signals in the axon terminals of olfactory receptor neurons (ORNs) do not follow the same adaptive properties as the firing activity measured at the antenna. While ORNs calcium responses are sustained on long timescales, calcium signals in the postsynaptic projection neurons (PNs) adapt within tens of seconds. We propose that this slow component of the postsynaptic response is mediated by a slow presynaptic depression of vesicle release and enables the combinatorial population activity of PNs to adjust to the mean and variance of fluctuating odor stimuli.
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Affiliation(s)
- Carlotta Martelli
- Molecular Neurobiology of Behavior, Johann-Friedrich-Blumenbach-Institute for Zoology and Anthropology, University of Goettingen, Goettingen, Germany.,Department of Biology, Neurobiology, University of Konstanz, Konstanz, Germany
| | - André Fiala
- Molecular Neurobiology of Behavior, Johann-Friedrich-Blumenbach-Institute for Zoology and Anthropology, University of Goettingen, Goettingen, Germany
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29
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Mohamed AAM, Retzke T, Das Chakraborty S, Fabian B, Hansson BS, Knaden M, Sachse S. Odor mixtures of opposing valence unveil inter-glomerular crosstalk in the Drosophila antennal lobe. Nat Commun 2019; 10:1201. [PMID: 30867415 PMCID: PMC6416470 DOI: 10.1038/s41467-019-09069-1] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 02/20/2019] [Indexed: 12/17/2022] Open
Abstract
Evaluating odor blends in sensory processing is a crucial step for signal recognition and execution of behavioral decisions. Using behavioral assays and 2-photon imaging, we have characterized the neural and behavioral correlates of mixture perception in the olfactory system of Drosophila. Mixtures of odors with opposing valences elicit strong inhibition in certain attractant-responsive input channels. This inhibition correlates with reduced behavioral attraction. We demonstrate that defined subsets of GABAergic interneurons provide the neuronal substrate of this computation at pre- and postsynaptic loci via GABAB- and GABAA receptors, respectively. Intriguingly, manipulation of single input channels by silencing and optogenetic activation unveils a glomerulus-specific crosstalk between the attractant- and repellent-responsive circuits. This inhibitory interaction biases the behavioral output. Such a form of selective lateral inhibition represents a crucial neuronal mechanism in the processing of conflicting sensory information.
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Affiliation(s)
- Ahmed A M Mohamed
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Hans-Knoell-Str. 8, 07745, Jena, Germany
| | - Tom Retzke
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Hans-Knoell-Str. 8, 07745, Jena, Germany
| | - Sudeshna Das Chakraborty
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Hans-Knoell-Str. 8, 07745, Jena, Germany
| | - Benjamin Fabian
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Hans-Knoell-Str. 8, 07745, Jena, Germany
| | - Bill S Hansson
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Hans-Knoell-Str. 8, 07745, Jena, Germany
| | - Markus Knaden
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Hans-Knoell-Str. 8, 07745, Jena, Germany
| | - Silke Sachse
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Hans-Knoell-Str. 8, 07745, Jena, Germany.
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30
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Chai PC, Cruchet S, Wigger L, Benton R. Sensory neuron lineage mapping and manipulation in the Drosophila olfactory system. Nat Commun 2019; 10:643. [PMID: 30733440 PMCID: PMC6367400 DOI: 10.1038/s41467-019-08345-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 12/28/2018] [Indexed: 11/20/2022] Open
Abstract
Nervous systems exhibit myriad cell types, but understanding how this diversity arises is hampered by the difficulty to visualize and genetically-probe specific lineages, especially at early developmental stages prior to expression of unique molecular markers. Here, we use a genetic immortalization method to analyze the development of sensory neuron lineages in the Drosophila olfactory system, from their origin to terminal differentiation. We apply this approach to define a fate map of nearly all olfactory lineages and refine the model of temporal patterns of lineage divisions. Taking advantage of a selective marker for the lineage that gives rise to Or67d pheromone-sensing neurons and a genome-wide transcription factor RNAi screen, we identify the spatial and temporal requirements for Pointed, an ETS family member, in this developmental pathway. Transcriptomic analysis of wild-type and Pointed-depleted olfactory tissue reveals a universal requirement for this factor as a switch-like determinant of fates in these sensory lineages. Few tools exist to study molecular diversity during neurodevelopment. Here the authors apply a genetic immortalization method in Drosophila to generate a fate map of olfactory sensory lineages, examine the relationships of this map and the neuroanatomical, molecular and evolutionary properties of the mature circuits, and identify a novel factor controlling lineage development.
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Affiliation(s)
- Phing Chian Chai
- Center for Integrative Genomics, Génopode Building, Faculty of Biology and Medicine, University of Lausanne, 1015, Lausanne, Switzerland
| | - Steeve Cruchet
- Center for Integrative Genomics, Génopode Building, Faculty of Biology and Medicine, University of Lausanne, 1015, Lausanne, Switzerland
| | - Leonore Wigger
- Lausanne Genomic Technologies Facility, Génopode Building, Faculty of Biology and Medicine, University of Lausanne, 1015, Lausanne, Switzerland.,Vital-IT Group, SIB Swiss Institute of Bioinformatics, 1015, Lausanne, Switzerland
| | - Richard Benton
- Center for Integrative Genomics, Génopode Building, Faculty of Biology and Medicine, University of Lausanne, 1015, Lausanne, Switzerland.
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31
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Horne JA, Langille C, McLin S, Wiederman M, Lu Z, Xu CS, Plaza SM, Scheffer LK, Hess HF, Meinertzhagen IA. A resource for the Drosophila antennal lobe provided by the connectome of glomerulus VA1v. eLife 2018; 7:e37550. [PMID: 30382940 PMCID: PMC6234030 DOI: 10.7554/elife.37550] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2018] [Accepted: 10/31/2018] [Indexed: 02/06/2023] Open
Abstract
Using FIB-SEM we report the entire synaptic connectome of glomerulus VA1v of the right antennal lobe in Drosophila melanogaster. Within the glomerulus we densely reconstructed all neurons, including hitherto elusive local interneurons. The fruitless-positive, sexually dimorphic VA1v included >11,140 presynaptic sites with ~38,050 postsynaptic dendrites. These connected input olfactory receptor neurons (ORNs, 51 ipsilateral, 56 contralateral), output projection neurons (18 PNs), and local interneurons (56 of >150 previously reported LNs). ORNs are predominantly presynaptic and PNs predominantly postsynaptic; newly reported LN circuits are largely an equal mixture and confer extensive synaptic reciprocity, except the newly reported LN2V with input from ORNs and outputs mostly to monoglomerular PNs, however. PNs were more numerous than previously reported from genetic screens, suggesting that the latter failed to reach saturation. We report a matrix of 192 bodies each having >50 connections; these form 88% of the glomerulus' pre/postsynaptic sites.
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Affiliation(s)
- Jane Anne Horne
- Department of Psychology and NeuroscienceLife Sciences Centre, Dalhousie UniversityHalifaxCanada
| | - Carlie Langille
- Department of Psychology and NeuroscienceLife Sciences Centre, Dalhousie UniversityHalifaxCanada
| | - Sari McLin
- Department of Psychology and NeuroscienceLife Sciences Centre, Dalhousie UniversityHalifaxCanada
| | - Meagan Wiederman
- Department of Psychology and NeuroscienceLife Sciences Centre, Dalhousie UniversityHalifaxCanada
| | - Zhiyuan Lu
- Department of Psychology and NeuroscienceLife Sciences Centre, Dalhousie UniversityHalifaxCanada
- Janelia Research Campus, Howard Hughes Medical InstituteVirginiaUnited States
| | - C Shan Xu
- Janelia Research Campus, Howard Hughes Medical InstituteVirginiaUnited States
| | - Stephen M Plaza
- Janelia Research Campus, Howard Hughes Medical InstituteVirginiaUnited States
| | - Louis K Scheffer
- Janelia Research Campus, Howard Hughes Medical InstituteVirginiaUnited States
| | - Harald F Hess
- Janelia Research Campus, Howard Hughes Medical InstituteVirginiaUnited States
| | - Ian A Meinertzhagen
- Department of Psychology and NeuroscienceLife Sciences Centre, Dalhousie UniversityHalifaxCanada
- Janelia Research Campus, Howard Hughes Medical InstituteVirginiaUnited States
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32
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Lin T, Li C, Liu J, Smith BH, Lei H, Zeng X. Glomerular Organization in the Antennal Lobe of the Oriental Fruit Fly Bactrocera dorsalis. Front Neuroanat 2018; 12:71. [PMID: 30233333 PMCID: PMC6127620 DOI: 10.3389/fnana.2018.00071] [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: 05/23/2018] [Accepted: 08/06/2018] [Indexed: 11/30/2022] Open
Abstract
The oriental fruit fly, Bactrocera dorsalis is one of the most destructive pests of horticultural crops in tropical and subtropical Asia. The insect relies heavily on its olfactory system to select suitable hosts for development and reproduction. To understand the neural basis of its odor-driven behaviors, it is fundamental to characterize the anatomy of its olfactory system. In this study, we investigated the anatomical organization of the antennal lobe (AL), the primary olfactory center, in B. dorsalis, and constructed a 3D glomerular atlas of the AL based on synaptic antibody staining combined with computerized 3D reconstruction. To facilitate identification of individual glomeruli, we also applied mass staining of olfactory sensory neurons (OSNs) and projection neurons (PNs). In total, 64 or 65 glomeruli are identifiable in both sexes based on their shape, size, and relative spatial relationship. The overall glomerular volume of two sexes is not statistically different. However, eight glomeruli are sexually dimorphic: four (named AM2, C1, L2, and L3) are larger in males, and four are larger in females (A3, AD1, DM3, and M1). The results from anterograde staining, obtained by applying dye in the antennal lobe, show that three typical medial, media lateral, and lateral antennal-lobe tracts form parallel connections between the antennal lobe and protocerebrum. In addition to these three tracts, we also found a transverse antennal-lobe tract. Based on the retrograde staining of the calyx in the mushroom body, we also characterize the arrangement of roots and cell body clusters linked to the medial antennal-lobe tracts. These data provide a foundation for future studies on the olfactory processing of host odors in B. dorsalis.
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Affiliation(s)
- Tao Lin
- Guangdong Engineering Research Center for Insect Behavior Regulation, South China Agricultural University, Guangzhou, China
| | - Chaofeng Li
- Guangdong Engineering Research Center for Insect Behavior Regulation, South China Agricultural University, Guangzhou, China
| | - Jiali Liu
- Guangdong Engineering Research Center for Insect Behavior Regulation, South China Agricultural University, Guangzhou, China
| | - Brian H. Smith
- School of Life Sciences, Arizona State University, Tempe, AZ, United States
| | - Hong Lei
- School of Life Sciences, Arizona State University, Tempe, AZ, United States
| | - Xinnian Zeng
- Guangdong Engineering Research Center for Insect Behavior Regulation, South China Agricultural University, Guangzhou, China
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33
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Newe A, Becker L. Three-Dimensional Portable Document Format (3D PDF) in Clinical Communication and Biomedical Sciences: Systematic Review of Applications, Tools, and Protocols. JMIR Med Inform 2018; 6:e10295. [PMID: 30087092 PMCID: PMC6103636 DOI: 10.2196/10295] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2018] [Revised: 05/07/2018] [Accepted: 05/24/2018] [Indexed: 12/20/2022] Open
Abstract
Background The Portable Document Format (PDF) is the standard file format for the communication of biomedical information via the internet and for electronic scholarly publishing. Although PDF allows for the embedding of three-dimensional (3D) objects and although this technology has great potential for the communication of such data, it is not broadly used by the scientific community or by clinicians. Objective The objective of this review was to provide an overview of existing publications that apply 3D PDF technology and the protocols and tools for the creation of model files and 3D PDFs for scholarly purposes to demonstrate the possibilities and the ways to use this technology. Methods A systematic literature review was performed using PubMed and Google Scholar. Articles searched for were in English, peer-reviewed with biomedical reference, published since 2005 in a journal or presented at a conference or scientific meeting. Ineligible articles were removed after screening. The found literature was categorized into articles that (1) applied 3D PDF for visualization, (2) showed ways to use 3D PDF, and (3) provided tools or protocols for the creation of 3D PDFs or necessary models. Finally, the latter category was analyzed in detail to provide an overview of the state of the art. Results The search retrieved a total of 902 items. Screening identified 200 in-scope publications, 13 covering the use of 3D PDF for medical purposes. Only one article described a clinical routine use case; all others were pure research articles. The disciplines that were covered beside medicine were many. In most cases, either animal or human anatomies were visualized. A method, protocol, software, library, or other tool for the creation of 3D PDFs or model files was described in 19 articles. Most of these tools required advanced programming skills and/or the installation of further software packages. Only one software application presented an all-in-one solution with a graphical user interface. Conclusions The use of 3D PDF for visualization purposes in clinical communication and in biomedical publications is still not in common use, although both the necessary technique and suitable tools are available, and there are many arguments in favor of this technique. The potential of 3D PDF usage should be disseminated in the clinical and biomedical community. Furthermore, easy-to-use, standalone, and free-of-charge software tools for the creation of 3D PDFs should be developed.
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Affiliation(s)
- Axel Newe
- Chair of Medical Informatics, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany.,NewTec GmbH, Pfaffenhofen an der Roth, Germany
| | - Linda Becker
- Chair of Health Psychology, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
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34
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Zheng Z, Lauritzen JS, Perlman E, Robinson CG, Nichols M, Milkie D, Torrens O, Price J, Fisher CB, Sharifi N, Calle-Schuler SA, Kmecova L, Ali IJ, Karsh B, Trautman ET, Bogovic JA, Hanslovsky P, Jefferis GSXE, Kazhdan M, Khairy K, Saalfeld S, Fetter RD, Bock DD. A Complete Electron Microscopy Volume of the Brain of Adult Drosophila melanogaster. Cell 2018; 174:730-743.e22. [PMID: 30033368 PMCID: PMC6063995 DOI: 10.1016/j.cell.2018.06.019] [Citation(s) in RCA: 452] [Impact Index Per Article: 75.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 02/28/2018] [Accepted: 06/10/2018] [Indexed: 12/16/2022]
Abstract
Drosophila melanogaster has a rich repertoire of innate and learned behaviors. Its 100,000-neuron brain is a large but tractable target for comprehensive neural circuit mapping. Only electron microscopy (EM) enables complete, unbiased mapping of synaptic connectivity; however, the fly brain is too large for conventional EM. We developed a custom high-throughput EM platform and imaged the entire brain of an adult female fly at synaptic resolution. To validate the dataset, we traced brain-spanning circuitry involving the mushroom body (MB), which has been extensively studied for its role in learning. All inputs to Kenyon cells (KCs), the intrinsic neurons of the MB, were mapped, revealing a previously unknown cell type, postsynaptic partners of KC dendrites, and unexpected clustering of olfactory projection neurons. These reconstructions show that this freely available EM volume supports mapping of brain-spanning circuits, which will significantly accelerate Drosophila neuroscience. VIDEO ABSTRACT.
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Affiliation(s)
- Zhihao Zheng
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - J Scott Lauritzen
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Eric Perlman
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Camenzind G Robinson
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Matthew Nichols
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | | | - Omar Torrens
- Coleman Technologies, Newtown Square, PA 19073, USA
| | - John Price
- Hudson Price Designs, Hingham, MA 02043, USA
| | - Corey B Fisher
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Nadiya Sharifi
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | | | - Lucia Kmecova
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Iqbal J Ali
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Bill Karsh
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Eric T Trautman
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - John A Bogovic
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Philipp Hanslovsky
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Gregory S X E Jefferis
- Division of Neurobiology, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK; Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK
| | - Michael Kazhdan
- Department of Computer Science, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Khaled Khairy
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Stephan Saalfeld
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Richard D Fetter
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Davi D Bock
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA.
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35
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Nischik ES, Krieger J. Evaluation of standard imaging techniques and volumetric preservation of nervous tissue in genetically identical offspring of the crayfish Procambarus fallax cf. virginalis (Marmorkrebs). PeerJ 2018; 6:e5181. [PMID: 30018856 PMCID: PMC6044273 DOI: 10.7717/peerj.5181] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 06/18/2018] [Indexed: 01/24/2023] Open
Abstract
In the field of comparative neuroanatomy, a meaningful interspecific comparison demands quantitative data referring to method-specific artifacts. For evaluating the potential of state-of-the-art imaging techniques in arthropod neuroanatomy, micro-computed X-ray microscopy (μCT) and two different approaches using confocal laser-scanning microscopy (cLSM) were applied to obtain volumetric data of the brain and selected neuropils in Procambarus fallax forma virginalis (Crustacea, Malacostraca, Decapoda). The marbled crayfish P. fallax cf. virginalis features a parthogenetic reproduction generating genetically identical offspring from unfertilized eggs. Therefore, the studied organism provides ideal conditions for the comparative analysis of neuroanatomical imaging techniques and the effect of preceding sample preparations of nervous tissue. We found that wet scanning of whole animals conducted with μCT turned out to be the least disruptive method. However, in an additional experiment it was discovered that fixation in Bouin’s solution, required for μCT scans, resulted in an average tissue shrinkage of 24% compared to freshly dissected and unfixed brains. The complete sample preparation using fixation in half-strength Karnovsky’s solution of dissected brains led to an additional volume decrease of 12.5%, whereas the preparation using zinc-formaldehyde as fixative resulted in a shrinkage of 5% in comparison to the volumes obtained by μCT. By minimizing individual variability, at least for aquatic arthropods, this pioneer study aims for the inference of method-based conversion factors in the future, providing a valuable tool for reducing quantitative neuroanatomical data already published to a common denominator. However, volumetric deviations could be shown for all experimental protocols due to methodological noise and/or phenotypic plasticity among genetically identical individuals. MicroCT using undried tissue is an appropriate non-disruptive technique for allometry of arthropod brains since spatial organ relationships are conserved and tissue shrinkage is minimized. Collecting tissue-based shrinkage factors according to specific sample preparations might allow a better comparability of volumetric data from the literature, even if another technique was applied.
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Affiliation(s)
- Emanuel S Nischik
- Zoological Institute and Museum, Cytology and Evolutionary Biology, University of Greifswald, Greifswald, Germany
| | - Jakob Krieger
- Zoological Institute and Museum, Cytology and Evolutionary Biology, University of Greifswald, Greifswald, Germany
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Jeanne JM, Fişek M, Wilson RI. The Organization of Projections from Olfactory Glomeruli onto Higher-Order Neurons. Neuron 2018; 98:1198-1213.e6. [PMID: 29909998 PMCID: PMC6051339 DOI: 10.1016/j.neuron.2018.05.011] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2018] [Revised: 04/19/2018] [Accepted: 05/04/2018] [Indexed: 11/27/2022]
Abstract
Each odorant receptor corresponds to a unique glomerulus in the brain. Projections from different glomeruli then converge in higher brain regions, but we do not understand the logic governing which glomeruli converge and which do not. Here, we use two-photon optogenetics to map glomerular connections onto neurons in the lateral horn, the region of the Drosophila brain that receives the majority of olfactory projections. We identify 39 morphological types of lateral horn neurons (LHNs) and show that different types receive input from different combinations of glomeruli. We find that different LHN types do not have independent inputs; rather, certain combinations of glomeruli converge onto many of the same LHNs and so are over-represented. Notably, many over-represented combinations are composed of glomeruli that prefer chemically dissimilar ligands whose co-occurrence indicates a behaviorally relevant "odor scene." The pattern of glomerulus-LHN connections thus represents a prediction of what ligand combinations will be most salient.
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Affiliation(s)
- James M Jeanne
- Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA
| | - Mehmet Fişek
- Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA
| | - Rachel I Wilson
- Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA.
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A 3D anatomical atlas of appendage musculature in the chelicerate arthropod Limulus polyphemus. PLoS One 2018; 13:e0191400. [PMID: 29444161 PMCID: PMC5812571 DOI: 10.1371/journal.pone.0191400] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 01/04/2018] [Indexed: 11/19/2022] Open
Abstract
Limulus polyphemus, an archetypal chelicerate taxon, has interested both biological and paleontological researchers due to its unique suite of anatomical features and as a useful modern analogue for fossil arthropod groups. To assist the study and documentation of this iconic taxon, we present a 3D atlas on the appendage musculature, with specific focus on the muscles of the cephalothoracic appendages. As L. polyphemus appendage musculature has been the focus of extensive study, depicting the muscles in 3D will facilitate a more complete understanding thereof for future researchers. A large museum specimen was CT scanned to illustrate the major exoskeletal features of L. polyphemus. Micro-CT scans of iodine-stained appendages from fresh, non-museum specimens were digitally dissected to interactively depict appendage sections and muscles. This study has revealed the presence of two new muscles: one within the pushing leg, located dorsally relative to all other patella muscles, and the other within the male pedipalp, located in the modified tibiotarsus. This atlas increases accessibility to important internal and external morphological features of L. polyphemus and reduces the need for destructive fresh tissue dissection of specimens. Scanning, digitally dissecting, and documenting taxa in 3D is a pivotal step towards creating permanent digital records of life on Earth.
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38
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Elucidating the Neuronal Architecture of Olfactory Glomeruli in the Drosophila Antennal Lobe. Cell Rep 2018; 16:3401-3413. [PMID: 27653699 DOI: 10.1016/j.celrep.2016.08.063] [Citation(s) in RCA: 98] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2016] [Revised: 07/15/2016] [Accepted: 08/18/2016] [Indexed: 11/21/2022] Open
Abstract
Olfactory glomeruli are morphologically conserved spherical compartments of the olfactory system, distinguishable solely by their chemosensory repertoire, anatomical position, and volume. Little is known, however, about their numerical neuronal composition. We therefore characterized their neuronal architecture and correlated these anatomical features with their functional properties in Drosophila melanogaster. We quantitatively mapped all olfactory sensory neurons (OSNs) innervating each glomerulus, including sexually dimorphic distributions. Our data reveal the impact of OSN number on glomerular dimensions and demonstrate yet unknown sex-specific differences in several glomeruli. Moreover, we quantified uniglomerular projection neurons for each glomerulus, which unraveled a glomerulus-specific numerical innervation. Correlation between morphological features and functional specificity showed that glomeruli innervated by narrowly tuned OSNs seem to possess a larger number of projection neurons and are involved in less lateral processing than glomeruli targeted by broadly tuned OSNs. Our study demonstrates that the neuronal architecture of each glomerulus encoding crucial odors is unique.
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Abstract
This chapter describes how to apply two-photon neuroimaging to study the insect olfactory system in vivo. It provides a complete protocol for insect brain functional imaging, with some additional remarks on the acquisition of morphological information from the living brain. We discuss the most important choices to make when buying or building a two-photon laser-scanning microscope. We illustrate different possibilities of animal preparation and brain tissue labeling for in vivo imaging. Finally, we give an overview of the main methods of image data processing and analysis, followed by a short description of pioneering applications of this imaging modality.
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Affiliation(s)
- Marco Paoli
- Department of Biology, University of Konstanz, Konstanz, Germany
| | - Albrecht Haase
- Department of Physics, University of Trento, Povo, Italy. .,Center for Mind/Brain Sciences, University of Trento, Trento, Italy.
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40
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Fischer S, Lu Z, Meinertzhagen IA. From two to three dimensions: The importance of the third dimension for evaluating the limits to neuronal miniaturization in insects. J Comp Neurol 2017; 526:653-662. [PMID: 29159850 DOI: 10.1002/cne.24358] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 11/02/2017] [Accepted: 11/03/2017] [Indexed: 11/06/2022]
Abstract
Most studies dealing with the limits to miniaturization in insect brains have until now relied on information based on data collected in two dimensions: either histological sections imaged by light microscopy, or electron micrographs of single ultrathin sections imaged by transmission electron microscopy (TEM). To test the validity of transferring information gained from two-dimensional images to the third dimension, we examined a 3D image stack from serial-section TEM (ssTEM) of the optic neuropiles of the miniature parasitic wasp Trichogramma brassicae (Bezdenko, 1968). We reinvestigated the proposed lower limit of 2 µm for the diameters of neuronal somata and found average volumes of 6.5 μm3 for lamina cells and 3.8 μm3 for medulla cells. We likewise found a limiting factor for the volume of nuclei, which averages 41.9% and 49.2% of the cell body volume, respectively, but that in turn the compactness of heterochromatin was not a limiting factor in the minimal volume of the nuclei. Finally, we also found a minimum axon diameter of 98 nm that could nevertheless accommodate axoplasmic mitochondria. Incorporating the third dimension thus proves critically important in avoiding volumetric misinterpretations of these values. We discuss the limitations of analyzing the effects of miniaturization from profile data of neurons and demonstrate that miniaturization within the nervous system can lie beyond previously described limits and in some cases is already present in the optic lobe neurons of T. brassicae.
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Affiliation(s)
- Stefan Fischer
- Department of Psychology and Neuroscience, Life Sciences Centre, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Zhiyuan Lu
- Department of Psychology and Neuroscience, Life Sciences Centre, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Ian A Meinertzhagen
- Department of Psychology and Neuroscience, Life Sciences Centre, Dalhousie University, Halifax, Nova Scotia, Canada
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41
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Crustacean olfactory systems: A comparative review and a crustacean perspective on olfaction in insects. Prog Neurobiol 2017; 161:23-60. [PMID: 29197652 DOI: 10.1016/j.pneurobio.2017.11.005] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 11/10/2017] [Accepted: 11/28/2017] [Indexed: 12/20/2022]
Abstract
Malacostracan crustaceans display a large diversity of sizes, morphs and life styles. However, only a few representatives of decapod taxa have served as models for analyzing crustacean olfaction, such as crayfish and spiny lobsters. Crustaceans bear multiple parallel chemosensory pathways represented by different populations of unimodal chemosensory and bimodal chemo- and mechanosensory sensilla on the mouthparts, the walking limbs and primarily on their two pairs of antennae. Here, we focus on the olfactory pathway associated with the unimodal chemosensory sensilla on the first antennal pair, the aesthetascs. We explore the diverse arrangement of these sensilla across malacostracan taxa and point out evolutionary transformations which occurred in the central olfactory pathway. We discuss the evolution of chemoreceptor proteins, comparative aspects of active chemoreception and the temporal resolution of crustacean olfactory system. Viewing the evolution of crustacean brains in light of energetic constraints can help us understand their functional morphology and suggests that in various crustacean lineages, the brains were simplified convergently because of metabolic limitations. Comparing the wiring of afferents, interneurons and output neurons within the olfactory glomeruli suggests a deep homology of insect and crustacean olfactory systems. However, both taxa followed distinct lineages during the evolutionary elaboration of their olfactory systems. A comparison with insects suggests their olfactory systems ö especially that of the vinegar fly ö to be superb examples for "economy of design". Such a comparison also inspires new thoughts about olfactory coding and the functioning of malacostracan olfactory systems in general.
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Electrical synapses mediate synergism between pheromone and food odors in Drosophila melanogaster. Proc Natl Acad Sci U S A 2017; 114:E9962-E9971. [PMID: 29087946 DOI: 10.1073/pnas.1712706114] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
In Drosophila melanogaster, the sex pheromone produced by males, cis-vaccenyl acetate (cVA), evokes a stereotypic gender-specific behavior in both males and females. As Drosophila adults feed, mate, and oviposit on food, they perceive the pheromone as a blend against a background of food odors. Previous studies have reported that food odors enhance flies' behavioral response to cVA, specifically in virgin females. However, how and where the different olfactory inputs interact has so far remained unknown. In this study, we elucidated the neuronal mechanism underlying the response at an anatomical, functional, and behavioral level. Our data show that in virgin females cVA and the complex food odor vinegar evoke a synergistic response in the cVA-responsive glomerulus DA1. This synergism, however, does not appear at the input level of the glomerulus, but is restricted to the projection neuron level only. Notably, it is abolished by a mutation in gap junctions in projection neurons and is found to be mediated by electrical synapses between excitatory local interneurons and projection neurons. As a behavioral consequence, we demonstrate that virgin females in the presence of vinegar become receptive more rapidly to courting males, while male courtship is not affected. Altogether, our results suggest that lateral excitation via gap junctions modulates odor tuning in the antennal lobe and drives synergistic interactions between two ecologically relevant odors, representing food and sex.
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43
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Münch D, Galizia CG. Take time: odor coding capacity across sensory neurons increases over time in Drosophila. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2017; 203:959-972. [PMID: 28852844 PMCID: PMC5696509 DOI: 10.1007/s00359-017-1209-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2017] [Revised: 08/11/2017] [Accepted: 08/14/2017] [Indexed: 11/25/2022]
Abstract
Due to the highly efficient olfactory code, olfactory sensory systems are able to reliably encode enormous numbers of olfactory stimuli. The olfactory code consists of combinatorial activation patterns across sensory neurons, thus its capacity exceeds the number of involved classes of sensory neurons by a manifold. Activation patterns are not static but vary over time, caused by the temporally complex response dynamics of the individual sensory neuron responses. We systematically analyzed the temporal dynamics of olfactory sensory neuron responses to a diverse set of odorants. We find that response dynamics depend on the combination of sensory neuron and odorant and that information about odorant identity can be extracted from the time course of the response. We also show that new response dynamics can arise when mixing two odorants. Our data show that temporal dynamics of odorant responses are able to significantly enhance the coding capacity of olfactory sensory systems.
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Affiliation(s)
- Daniel Münch
- Neurobiology, University of Konstanz, 78457, Konstanz, Germany. .,Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Av. Brasília, 1400-038, Lisbon, Portugal.
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44
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Strube-Bloss MF, Grabe V, Hansson BS, Sachse S. Calcium imaging revealed no modulatory effect on odor-evoked responses of the Drosophila antennal lobe by two populations of inhibitory local interneurons. Sci Rep 2017; 7:7854. [PMID: 28798324 PMCID: PMC5552818 DOI: 10.1038/s41598-017-08090-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 07/06/2017] [Indexed: 12/26/2022] Open
Abstract
Although we have considerable knowledge about how odors are represented in the antennal lobe (AL), the insects’ analogue to the olfactory bulb, we still do not fully understand how the different neurons in the AL network contribute to the olfactory code. In Drosophila melanogaster we can selectively manipulate specific neuronal populations to elucidate their function in odor processing. Here we silenced the synaptic transmission of two distinct subpopulations of multiglomerular GABAergic local interneurons (LN1 and LN2) using shibire (shits) and analyzed their impact on odor-induced glomerular activity at the AL input and output level. We verified that the employed shits construct effectively blocked synaptic transmission to the AL when expressed in olfactory sensory neurons. Notably, selective silencing of both LN populations did not significantly affect the odor-evoked activity patterns in the AL. Neither the glomerular input nor the glomerular output activity was modulated in comparison to the parental controls. We therefore conclude that these LN subpopulations, which cover one third of the total LN number, are not predominantly involved in odor identity coding per se. As suggested by their broad innervation patterns and contribution to long-term adaptation, they might contribute to AL–computation on a global and longer time scale.
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Affiliation(s)
- Martin F Strube-Bloss
- Max Planck Institute for Chemical Ecology, Department of Evolutionary Neuroethology, Hans-Knöll-Straße 8, 07745, Jena, Germany.,Department of Behavioral Physiology & Sociobiology, Theodor-Boveri-Institute of Bioscience, Biocenter University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Veit Grabe
- Max Planck Institute for Chemical Ecology, Department of Evolutionary Neuroethology, Hans-Knöll-Straße 8, 07745, Jena, Germany
| | - Bill S Hansson
- Max Planck Institute for Chemical Ecology, Department of Evolutionary Neuroethology, Hans-Knöll-Straße 8, 07745, Jena, Germany
| | - Silke Sachse
- Max Planck Institute for Chemical Ecology, Department of Evolutionary Neuroethology, Hans-Knöll-Straße 8, 07745, Jena, Germany.
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45
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Olfactory coding from the periphery to higher brain centers in the Drosophila brain. BMC Biol 2017; 15:56. [PMID: 28666437 PMCID: PMC5493115 DOI: 10.1186/s12915-017-0389-z] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2017] [Accepted: 06/02/2017] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND Odor information is processed through multiple receptor-glomerular channels in the first order olfactory center, the antennal lobe (AL), then reformatted into higher brain centers and eventually perceived by the fly. To reveal the logic of olfaction, it is fundamental to map odor representations from the glomerular channels into higher brain centers. RESULTS We characterize odor response profiles of AL projection neurons (PNs) originating from 31 glomeruli using whole cell patch-clamp recordings in Drosophila melanogaster. We reveal that odor representation from olfactory sensory neurons to PNs is generally conserved, while transformation of odor tuning curves is glomerulus-dependent. Reconstructions of PNs reveal that attractive and aversive odors are represented in different clusters of glomeruli in the AL. These separate representations are preserved into higher brain centers, where attractive and aversive odors are segregated into two regions in the lateral horn and partly separated in the mushroom body calyx. CONCLUSIONS Our study reveals spatial representation of odor valence coding from the AL to higher brain centers. These results provide a global picture of the olfactory circuit design underlying innate odor-guided behavior.
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Knecht ZA, Silbering AF, Cruz J, Yang L, Croset V, Benton R, Garrity PA. Ionotropic Receptor-dependent moist and dry cells control hygrosensation in Drosophila. eLife 2017. [PMID: 28621663 PMCID: PMC5495567 DOI: 10.7554/elife.26654] [Citation(s) in RCA: 103] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Insects use hygrosensation (humidity sensing) to avoid desiccation and, in vectors such as mosquitoes, to locate vertebrate hosts. Sensory neurons activated by either dry or moist air (‘dry cells’ and ‘moist cells’) have been described in many insects, but their behavioral roles and the molecular basis of their hygrosensitivity remain unclear. We recently reported that Drosophila hygrosensation relies on three Ionotropic Receptors (IRs) required for dry cell function: IR25a, IR93a and IR40a (Knecht et al., 2016). Here, we discover Drosophila moist cells and show that they require IR25a and IR93a together with IR68a, a conserved, but orphan IR. Both IR68a- and IR40a-dependent pathways drive hygrosensory behavior: each is important for dry-seeking by hydrated flies and together they underlie moist-seeking by dehydrated flies. These studies reveal that humidity sensing in Drosophila, and likely other insects, involves the combined activity of two molecularly related but neuronally distinct hygrosensing systems. DOI:http://dx.doi.org/10.7554/eLife.26654.001
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Affiliation(s)
- Zachary A Knecht
- National Center for Behavioral Genomics, Brandeis University, Waltham, United States.,Volen Center for Complex Systems, Brandeis University, Waltham, United States.,Department of Biology, Brandeis University, Waltham, United States
| | - Ana F Silbering
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Joyner Cruz
- National Center for Behavioral Genomics, Brandeis University, Waltham, United States.,Volen Center for Complex Systems, Brandeis University, Waltham, United States.,Department of Biology, Brandeis University, Waltham, United States
| | - Ludi Yang
- National Center for Behavioral Genomics, Brandeis University, Waltham, United States.,Volen Center for Complex Systems, Brandeis University, Waltham, United States.,Department of Biology, Brandeis University, Waltham, United States
| | - Vincent Croset
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Richard Benton
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Paul A Garrity
- National Center for Behavioral Genomics, Brandeis University, Waltham, United States.,Volen Center for Complex Systems, Brandeis University, Waltham, United States.,Department of Biology, Brandeis University, Waltham, United States
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47
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Tobin WF, Wilson RI, Lee WCA. Wiring variations that enable and constrain neural computation in a sensory microcircuit. eLife 2017; 6. [PMID: 28530904 PMCID: PMC5440167 DOI: 10.7554/elife.24838] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Accepted: 04/23/2017] [Indexed: 11/13/2022] Open
Abstract
Neural network function can be shaped by varying the strength of synaptic connections. One way to achieve this is to vary connection structure. To investigate how structural variation among synaptic connections might affect neural computation, we examined primary afferent connections in the Drosophila olfactory system. We used large-scale serial section electron microscopy to reconstruct all the olfactory receptor neuron (ORN) axons that target a left-right pair of glomeruli, as well as all the projection neurons (PNs) postsynaptic to these ORNs. We found three variations in ORN→PN connectivity. First, we found a systematic co-variation in synapse number and PN dendrite size, suggesting total synaptic conductance is tuned to postsynaptic excitability. Second, we discovered that PNs receive more synapses from ipsilateral than contralateral ORNs, providing a structural basis for odor lateralization behavior. Finally, we found evidence of imprecision in ORN→PN connections that can diminish network performance. DOI:http://dx.doi.org/10.7554/eLife.24838.001
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Affiliation(s)
- William F Tobin
- Department of Neurobiology, Harvard Medical School, Boston, United States
| | - Rachel I Wilson
- Department of Neurobiology, Harvard Medical School, Boston, United States
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48
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Paoli M, Münch D, Haase A, Skoulakis E, Turin L, Galizia CG. Minute Impurities Contribute Significantly to Olfactory Receptor Ligand Studies: Tales from Testing the Vibration Theory. eNeuro 2017; 4:ENEURO.0070-17.2017. [PMID: 28670618 PMCID: PMC5490255 DOI: 10.1523/eneuro.0070-17.2017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2017] [Revised: 05/18/2017] [Accepted: 05/19/2017] [Indexed: 11/27/2022] Open
Abstract
Several studies have attempted to test the vibrational hypothesis of odorant receptor activation in behavioral and physiological studies using deuterated compounds as odorants. The results have been mixed. Here, we attempted to test how deuterated compounds activate odorant receptors using calcium imaging of the fruit fly antennal lobe. We found specific activation of one area of the antennal lobe corresponding to inputs from a specific receptor. However, upon more detailed analysis, we discovered that an impurity of 0.0006% ethyl acetate in a chemical sample of benzaldehyde-d5 was entirely responsible for a sizable odorant-evoked response in Drosophila melanogaster olfactory receptor cells expressing dOr42b. Without gas chromatographic purification within the experimental setup, this impurity would have created a difference in the responses of deuterated and nondeuterated benzaldehyde, suggesting that dOr42b be a vibration sensitive receptor, which we show here not to be the case. Our results point to a broad problem in the literature on use of non-GC-pure compounds to test receptor selectivity, and we suggest how the limitations can be overcome in future studies.
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Affiliation(s)
- M. Paoli
- Neurobiology, University of Konstanz, Konstanz, 78457, Germany
- Department of Physics and Center for Mind/Brain Sciences, University of Trento, Povo, TN 38123, Italy
| | - D. Münch
- Neurobiology, University of Konstanz, Konstanz, 78457, Germany
| | - A. Haase
- Department of Physics and Center for Mind/Brain Sciences, University of Trento, Povo, TN 38123, Italy
| | - E. Skoulakis
- Division of Neuroscience, Biomedical Sciences Research Centre Alexander Fleming, Vari 16672, Greece
| | - L. Turin
- Division of Neuroscience, Biomedical Sciences Research Centre Alexander Fleming, Vari 16672, Greece
| | - C. G. Galizia
- Neurobiology, University of Konstanz, Konstanz, 78457, Germany
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50
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Morphological and Transcriptomic Analysis of a Beetle Chemosensory System Reveals a Gnathal Olfactory Center. BMC Biol 2016; 14:90. [PMID: 27751175 PMCID: PMC5067906 DOI: 10.1186/s12915-016-0304-z] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 09/05/2016] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND The red flour beetle Tribolium castaneum is an emerging insect model organism representing the largest insect order, Coleoptera, which encompasses several serious agricultural and forest pests. Despite the ecological and economic importance of beetles, most insect olfaction studies have so far focused on dipteran, lepidopteran, or hymenopteran systems. RESULTS Here, we present the first detailed morphological description of a coleopteran olfactory pathway in combination with genome-wide expression analysis of the relevant gene families involved in chemoreception. Our study revealed that besides the antennae, also the mouthparts are highly involved in olfaction and that their respective contribution is processed separately. In this beetle, olfactory sensory neurons from the mouthparts project to the lobus glomerulatus, a structure so far only characterized in hemimetabolous insects, as well as to a so far non-described unpaired glomerularly organized olfactory neuropil in the gnathal ganglion, which we term the gnathal olfactory center. The high number of functional odorant receptor genes expressed in the mouthparts also supports the importance of the maxillary and labial palps in olfaction of this beetle. Moreover, gustatory perception seems equally distributed between antenna and mouthparts, since the number of expressed gustatory receptors is similar for both organs. CONCLUSIONS Our analysis of the T. castaneum chemosensory system confirms that olfactory and gustatory perception are not organotopically separated to the antennae and mouthparts, respectively. The identification of additional olfactory processing centers, the lobus glomerulatus and the gnathal olfactory center, is in contrast to the current picture that in holometabolous insects all olfactory inputs allegedly converge in the antennal lobe. These findings indicate that Holometabola have evolved a wider variety of solutions to chemoreception than previously assumed.
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