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Vainer Y, Wang Y, Huff RM, Ghaninia M, Coutinho-Abreu IV, Sar-Shalom E, Ruiz C, Perets D, Yakir E, Rajamanickam D, Warburg A, Papathanos P, Akbari OS, Ignell R, Riffell JA, Pitts RJ, Bohbot JD. The evolution of borneol repellency in culicine mosquitoes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.01.548337. [PMID: 37577635 PMCID: PMC10418152 DOI: 10.1101/2023.08.01.548337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
Insects have developed remarkable adaptations to effectively interact with plant secondary metabolites and utilize them as cues to identify suitable hosts. Consequently, humans have used aromatic plants for centuries to repel mosquitoes. The repellent effects of plant volatile compounds are mediated through olfactory structures present in the antennae, and maxillary palps of mosquitoes. Mosquito maxillary palps contain capitate-peg sensilla, which house three olfactory sensory neurons, of which two are mainly tuned to either carbon dioxide or octenol - two animal host odorants. However, the third neuron, which expresses the OR49 receptor, has remained without a known ecologically-relevant odorant since its initial discovery. In this study, we used odorant mixtures and terpenoid-rich Cannabis essential oils to investigate the activation of OR49. Our results demonstrate that two monoterpenoids, borneol and camphor, selectively activate OR49, and OR9-expressing neurons, as well as the MD3 glomerulus in the antennal lobe. We confirm that borneol repels female mosquitoes, and knocking out the gene encoding the OR49 receptor suppresses the response of the corresponding olfactory sensory neuron. Importantly, this molecular mechanism of action is conserved across culicine mosquito species, underscoring its significance in their olfactory systems.
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Affiliation(s)
- Yuri Vainer
- Department of Entomology, The Hebrew University of Jerusalem, The Robert H. Smith Faculty of Agriculture, Food and Environment, Rehovot, Israel
| | - Yinliang Wang
- Department of Entomology, The Hebrew University of Jerusalem, The Robert H. Smith Faculty of Agriculture, Food and Environment, Rehovot, Israel
- Northeast Normal University, China
| | - Robert M Huff
- Department of Biology, Baylor University, Waco, Texas, USA
| | - Majid Ghaninia
- Unit of Chemical Ecology, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp, Sweden
| | - Iliano V Coutinho-Abreu
- School of Biological Sciences, Department of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA, USA
| | - Evyatar Sar-Shalom
- Department of Entomology, The Hebrew University of Jerusalem, The Robert H. Smith Faculty of Agriculture, Food and Environment, Rehovot, Israel
| | - Carlos Ruiz
- Department of Biology, University of Washington, Seattle, WA, USA 98195
| | - Dor Perets
- Department of Entomology, The Hebrew University of Jerusalem, The Robert H. Smith Faculty of Agriculture, Food and Environment, Rehovot, Israel
| | - Esther Yakir
- Department of Entomology, The Hebrew University of Jerusalem, The Robert H. Smith Faculty of Agriculture, Food and Environment, Rehovot, Israel
| | | | - Alon Warburg
- Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada, The Kuvin Centre for the Study of Infectious and Tropical Diseases, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Philippos Papathanos
- Department of Entomology, The Hebrew University of Jerusalem, The Robert H. Smith Faculty of Agriculture, Food and Environment, Rehovot, Israel
| | - Omar S Akbari
- School of Biological Sciences, Department of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA, USA
| | - Rickard Ignell
- Unit of Chemical Ecology, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp, Sweden
| | - Jeff A Riffell
- Department of Biology, University of Washington, Seattle, WA, USA 98195
| | - R Jason Pitts
- Department of Biology, Baylor University, Waco, Texas, USA
| | - Jonathan D Bohbot
- Department of Entomology, The Hebrew University of Jerusalem, The Robert H. Smith Faculty of Agriculture, Food and Environment, Rehovot, Israel
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Chen ST, Kowalewski J, Ray A. Prolonged activation of carbon dioxide-sensitive neurons in mosquitoes. Interface Focus 2021; 11:20200043. [PMID: 33633836 DOI: 10.1098/rsfs.2020.0043] [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] [Accepted: 12/09/2020] [Indexed: 11/12/2022] Open
Abstract
Many insects can detect carbon dioxide (CO2) plumes using a conserved receptor made up of members of the gustatory receptor (Gr) family Gr1, Gr2 and Gr3. Mosquitoes are attracted to host animals for blood meals using plumes of CO2 in the exhaled breath using the receptor expressed in the A neuron of the capitate peg sensilla type on the maxillary palps. The receptor is known to also detect several other classes of odorants, including ones emitted from human skin. Here, we discover that a common skin odorant, butyric acid, can cause a phasic activation followed by an unusually prolonged tonic activity after the stimulus is over in the CO2 neurons of mosquitoes. The effect is conserved in both Aedes aegypti and Anopheles gambiae mosquitoes. This raises a question about its role in a mosquito's preference for the skin odour of different individuals. Butyric acid belongs to a small number of odorants known to cause the prolonged activation of the CO2 receptor. A chemical informatic analysis identifies a specific set of physico-chemical features that can be used in a machine learning predictive model for the prolonged activators. Interestingly, this set is different from physico-chemical features selected for activators or inhibitors, indicating that each has a distinct structural basis. The structural understanding opens up an opportunity to find novel ligands to manipulate the CO2 receptor and mosquito behaviour.
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Affiliation(s)
- Stephanie Turner Chen
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, CA 92521, USA
| | - Joel Kowalewski
- Interdepartmental Neuroscience Program, University of California, Riverside, CA 92521, USA
| | - Anandasankar Ray
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, CA 92521, USA.,Interdepartmental Neuroscience Program, University of California, Riverside, CA 92521, USA
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KC P, Chu X, Kvello P, Zhao XC, Wang GR, Berg BG. Revisiting the Labial Pit Organ Pathway in the Noctuid Moth, Helicoverpa armigera. Front Physiol 2020; 11:202. [PMID: 32256380 PMCID: PMC7090773 DOI: 10.3389/fphys.2020.00202] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 02/21/2020] [Indexed: 11/24/2022] Open
Abstract
Lepidopteran species detect CO2 via a specialized organ located on the peripheral segment of the labial palps, the labial palp pit organ (LPO). Based on tracing of LPO sensory neurons targeting one distinct antennal-lobe glomerulus, Kent and her colleagues described the projections originating from the LPO in the sphinx moth as "an accessory olfactory pathway in Lepidoptera" already in the 1980 ties. In spite of similar reports from studies of other lepidopteran species, however, it has been an unresolved issue whether additional termination areas of the labial nerve, such as the gnathal ganglion (GNG) and the ventral nerve cord, are actually output sites of LPO neurons. Since the previous studies have interpreted slightly differently about the projection pattern occurring from the classical mass staining, we performed selective mass staining from the inside of the pit and from the outer surface of the peripheral palp. The results demonstrated that the LPO sensory neurons project exclusively to the LPO glomerulus (LPOG), whereas the non-LPO sensory neurons target the GNG and the ventral nerve cord. Additional iontophoretic staining of individual LPO sensory neurons, performed from the LPO and the LPOG, showed three morphological neuron types: one bilateral targeting the LPOG in both antennal lobes, one unilateral targeting the ipsilateral LPOG only, and one contralateral targeting the LPOG in the other antennal lobe. Finally, to explore putative differences in the projection pattern of neurons housed by two previously reported sensillum types in the pit, i.e., hair-shaped sensilla located distally and club-shaped sensilla located proximally, we performed mass staining from two different levels of the peripheral palp. We found a projection pattern implying stronger innervation of the ipsi- than the contralateral LPOG in both staining experiments.
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Affiliation(s)
- Pramod KC
- Chemosensory Laboratory, Department of Psychology, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Xi Chu
- Chemosensory Laboratory, Department of Psychology, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Pål Kvello
- Department of Teacher Education, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Xin-Cheng Zhao
- Department of Entomology, College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Gui-Rong Wang
- State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Bente Gunnveig Berg
- Chemosensory Laboratory, Department of Psychology, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
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4
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Batista EPA, Mapua SA, Ngowo H, Matowo NS, Melo EF, Paixão KS, Eiras AE, Okumu FO. Videographic analysis of flight behaviours of host-seeking Anopheles arabiensis towards BG-Malaria trap. PLoS One 2019; 14:e0220563. [PMID: 31365584 PMCID: PMC6668822 DOI: 10.1371/journal.pone.0220563] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 07/18/2019] [Indexed: 11/19/2022] Open
Abstract
The BG-Malaria trap (BGM) is an adaptation of the well-known BG-Sentinel trap (BGS) with greater trapping efficiencies for anopheline and culicine mosquitoes. Its continued optimization requires greater understanding of mosquito flight behaviors near it. We used three high-resolution infrared cameras (68 frames/second) to track flight behaviors of laboratory-reared Anopheles arabiensis females in vicinity of the BGM in comparison with BGS. Additional comparisons were done for BGM at 20, 40 and 80cm heights, and for BGMs baited with Ifakara blend plus CO2, CO2 alone, or no bait. More mosquitoes were observed near BGM than BGS. Both BGMs installed 20cm above the floor and baited with CO2 received more visits by host-seeking mosquitoes than the other BGMs evaluated in their respective experiments. Trap designs, height and attractants all influence mosquito activity in vicinity of the traps which can be readily visualized using infrared cameras to accelerate trap development and testing. The greater activity of host-seeking mosquitoes near BGM than BGS supports the proven superiority of BGM traps in field and semi-field settings.
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Affiliation(s)
- Elis P. A. Batista
- Laboratory of Innovation Technologies in Vector Control, Department of Parasitology, Biological Sciences Institute, Federal University of Minas Gerais, Belo Horizonte, Brazil
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
| | - Salum A. Mapua
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
- School of Life Sciences, University of Keele, Staffordshire, United Kingdom
- School of Environment and Life Sciences, University of Salford, Manchester, United Kingdom
| | - Halfan Ngowo
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | - Nancy S. Matowo
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
- University of Basel, Basel, Switzerland
- Swiss Tropical and Public Health Institute, Basel, Switzerland
| | - Elizangela F. Melo
- Laboratory of Innovation Technologies in Vector Control, Department of Parasitology, Biological Sciences Institute, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Kelly S. Paixão
- Laboratory of Innovation Technologies in Vector Control, Department of Parasitology, Biological Sciences Institute, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Alvaro E. Eiras
- Laboratory of Innovation Technologies in Vector Control, Department of Parasitology, Biological Sciences Institute, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Fredros O. Okumu
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
- School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Parktown, Republic of South Africa
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Dekel A, Pitts RJ, Yakir E, Bohbot JD. Evolutionarily conserved odorant receptor function questions ecological context of octenol role in mosquitoes. Sci Rep 2016; 6:37330. [PMID: 27849027 PMCID: PMC5110965 DOI: 10.1038/srep37330] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 10/11/2016] [Indexed: 11/08/2022] Open
Abstract
Olfaction is a key insect adaptation to a wide range of habitats. In the last thirty years, the detection of octenol by blood-feeding insects has been primarily understood in the context of animal host-seeking. The recent discovery of a conserved octenol receptor gene in the strictly nectar-feeding elephant mosquito Toxorhynchites amboinensis (TaOr8) suggests a different biological role. Here, we show that TaOR8 is a functional ortholog of its counterparts in blood-feeding mosquitoes displaying selectivity towards the (R)-enantiomer of octenol and susceptibility to the insect repellent DEET. These findings suggest that while the function of OR8 has been maintained throughout mosquito evolution, the context in which this receptor is operating has diverged in blood and nectar-feeding mosquitoes.
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Affiliation(s)
- Amir Dekel
- Department of Entomology, The Hebrew University of Jerusalem, Rehovot 76100, Israel
| | - Ronald J. Pitts
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Esther Yakir
- Department of Entomology, The Hebrew University of Jerusalem, Rehovot 76100, Israel
| | - Jonathan D. Bohbot
- Department of Entomology, The Hebrew University of Jerusalem, Rehovot 76100, Israel
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Abstract
Sexual dimorphism, a poorly understood but crucial aspect of vector mosquito biology, encompasses sex-specific physical, physiological, and behavioral traits related to mosquito reproduction. The study of mosquito sexual dimorphism has largely focused on analysis of the differences between adult female and male mosquitoes, particularly with respect to sex-specific behaviors related to disease transmission. However, sexually dimorphic behaviors are the products of differential gene expression that initiates during development and therefore must also be studied during development. Recent technical advancements are facilitating functional genetic studies in the dengue vector Aedes aegypti, an emerging model for mosquito development. These methodologies, many of which could be extended to other non-model insect species, are facilitating analysis of the development of sexual dimorphism in neural tissues, particularly the olfactory system. These studies are providing insight into the neurodevelopmental genetic basis for sexual dimorphism in vector mosquitoes.
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Affiliation(s)
- Molly Duman-Scheel
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, South Bend, Indiana, USA; Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, USA; Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - Zainulabeuddin Syed
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, USA; Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, USA
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7
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Nyasembe VO, Tchouassi DP, Kirwa HK, Foster WA, Teal PEA, Borgemeister C, Torto B. Development and assessment of plant-based synthetic odor baits for surveillance and control of malaria vectors. PLoS One 2014; 9:e89818. [PMID: 24587059 PMCID: PMC3933673 DOI: 10.1371/journal.pone.0089818] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Accepted: 01/26/2014] [Indexed: 11/22/2022] Open
Abstract
Background Recent malaria vector control measures have considerably reduced indoor biting mosquito populations. However, reducing the outdoor biting populations remains a challenge because of the unavailability of appropriate lures to achieve this. This study sought to test the efficacy of plant-based synthetic odor baits in trapping outdoor populations of malaria vectors. Methodology and Principal Finding Three plant-based lures ((E)-linalool oxide [LO], (E)-linalool oxide and (E)-β-ocimene [LO + OC], and a six-component blend comprising (E)-linalool oxide, (E)-β-ocimene, hexanal, β-pinene, limonene, and (E)-β-farnesene [Blend C]), were tested alongside an animal/human-based synthetic lure (comprising heptanal, octanal, nonanal, and decanal [Blend F]) and worn socks in a malaria endemic zone in the western part of Kenya. Mosquito Magnet-X (MM-X) and lightless Centre for Disease Control (CDC) light traps were used. Odor-baited traps were compared with traps baited with either solvent alone or solvent + carbon dioxide (controls) for 18 days in a series of randomized incomplete-block designs of days × sites × treatments. The interactive effect of plant and animal/human odor was also tested by combining LO with either Blend F or worn socks. Our results show that irrespective of trap type, traps baited with synthetic plant odors compared favorably to the same traps baited with synthetic animal odors and worn socks in trapping malaria vectors, relative to the controls. Combining LO and worn socks enhanced trap captures of Anopheles species while LO + Blend F recorded reduced trap capture. Carbon dioxide enhanced total trap capture of both plant- and animal/human-derived odors. However, significantly higher proportions of male and engorged female Anopheles gambiae s.l. were caught when the odor treatments did not include carbon dioxide. Conclusion and Significance The results highlight the potential of plant-based odors and specifically linalool oxide, with or without carbon dioxide, for surveillance and mass trapping of malaria vectors.
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Affiliation(s)
- Vincent O. Nyasembe
- Behavioral and Chemical Ecology Department, International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
| | - David P. Tchouassi
- Behavioral and Chemical Ecology Department, International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
| | - Hillary K. Kirwa
- Behavioral and Chemical Ecology Department, International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
| | - Woodbridge A. Foster
- Department of Ecology and Organismal Biology, The Ohio State University, Columbus, Ohio, United States of America
| | - Peter E. A. Teal
- Center for Medical, Agricultural, and Veterinary Entomology, U.S. Department of Agriculture, Agricultural Research Service, Gainesville, Florida, United States of America
| | - Christian Borgemeister
- Behavioral and Chemical Ecology Department, International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
- Center for Development Research, University of Bonn, Bonn, Germany
| | - Baldwyn Torto
- Behavioral and Chemical Ecology Department, International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
- * E-mail:
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Tauxe GM, MacWilliam D, Boyle SM, Guda T, Ray A. Targeting a dual detector of skin and CO2 to modify mosquito host seeking. Cell 2014; 155:1365-79. [PMID: 24315103 DOI: 10.1016/j.cell.2013.11.013] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Revised: 08/20/2013] [Accepted: 11/05/2013] [Indexed: 01/08/2023]
Abstract
Female mosquitoes that transmit deadly diseases locate human hosts by detecting exhaled CO2 and skin odor. The identities of olfactory neurons and receptors required for attraction to skin odor remain a mystery. Here, we show that the CO2-sensitive olfactory neuron is also a sensitive detector of human skin odorants in both Aedes aegypti and Anopheles gambiae. We demonstrate that activity of this neuron is important for attraction to skin odor, establishing it as a key target for intervention. We screen ~0.5 million compounds in silico and identify several CO2 receptor ligands, including an antagonist that reduces attraction to skin and an agonist that lures mosquitoes to traps as effectively as CO2. Analysis of the CO2 receptor ligand space provides a foundation for understanding mosquito host-seeking behavior and identifies odors that are potentially safe, pleasant, and affordable for use in a new generation of mosquito control strategies worldwide.
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Affiliation(s)
- Genevieve M Tauxe
- Department of Entomology, University of California, Riverside, Riverside, CA 92521, USA
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Grant AJ, Muskavitch MAT, O’Connell RJ. Malaria infection does not affect the sensitivity of peripheral receptor neurons in Anopheles stephensi. Parasit Vectors 2013; 6:134. [PMID: 23642231 PMCID: PMC3659000 DOI: 10.1186/1756-3305-6-134] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Accepted: 04/23/2013] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Mosquitoes transmit many important diseases including malaria, dengue and yellow fever. Disease transmission from one vertebrate host to another depends on repeated blood feedings by single mosquitoes. In order for the mosquito to acquire the blood that it needs to complete oogenesis, the insect must locate a suitable host. Olfactory cues (including carbon dioxide) released by the host and detected by the mosquito are the primary signals that vector insects use for host location. Previous studies have suggested that the physiological status - including bacterial, fungal, viral and Plasmodium infections - can modulate aspects of behavior in haematophagous insects. METHODS Standard electrophysiological techniques were used to record extracellular responses from the receptor neurons located in sensilla found on the maxillary palps of the insects. The recording microelectrode was inserted through the cuticle at the base of an individual sensillum and the extracellular electrical signals obtained from the three neurons within the sensillum were recorded. Stimulations consisted of 2 s pulses of the desired concentrations of CO(2) or dosages of 1-octen-3-ol. RESULTS Accordingly, we were interested in determining whether Plasmodium infection affects the sensitivity of those peripheral olfactory sensors that are involved in host-seeking in mosquitoes. Our studies indicate that infection of female Anopheles stephensi with Plasmodium berghei does not alter the response characteristics of the neurons innervating the maxillary palp sensilla that respond to the attractants carbon dioxide and 1-octen-3-ol. Although the response characteristics of the peripheral sensory neurons are not affected by infection status, we found that the age of the mosquito alone does affect the threshold of sensitivity of these neurons to carbon dioxide. The proportion of older insects (21-30 d post-emergence) that responds to 150 ppm carbon dioxide is higher than the proportion that responds among younger insects (1-10 d post-emergence). CONCLUSIONS Anopheles stephensi infected with Plasmodium berghei exhibit sensitivities to stimulation with carbon dioxide and 1-octen-3-ol similar to those of uninfected mosquitoes. However, the age of the infected or uninfected mosquito does affect the threshold of sensitivity of these neurons to carbon dioxide.
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Affiliation(s)
- Alan J Grant
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Harvard University, 665 Huntington Avenue, Boston, Massachusetts 02115, USA
| | - Marc A T Muskavitch
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Harvard University, 665 Huntington Avenue, Boston, Massachusetts 02115, USA
- Biology Department, Boston College, 140 Commonwealth Avenue, Chestnut Hill, Massachusetts, 02467, USA
| | - Robert J O’Connell
- University of Massachusetts Medical School, Worcester, Massachusetts, 01505, USA
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10
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Turner SL, Li N, Guda T, Githure J, Cardé RT, Ray A. Ultra-prolonged activation of CO2-sensing neurons disorients mosquitoes. Nature 2011; 474:87-91. [PMID: 21637258 PMCID: PMC3150595 DOI: 10.1038/nature10081] [Citation(s) in RCA: 125] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Accepted: 04/01/2011] [Indexed: 11/25/2022]
Abstract
CO2 present in exhaled air is the most important sensory cue for female blood-feeding mosquitoes, causing activation of long-distance host-seeking flight, navigation towards the vertebrate host1, and, in the case of Aedes aegypti, increased sensitivity to skin odours2. The CO2 detection machinery is therefore an ideal target to disrupt host seeking. We use electrophysiological assays to identify a volatile odourant that causes an unusual, ultra-prolonged activation of CO2-detecting neurons in three major disease-transmitting mosquitoes: Anopheles gambiae, Culex quinquefasciatus and A. aegypti. Importantly ultra-prolonged activation of this neuron severely compromises its ability to subsequently detect CO2 for several minutes. We also identify odours that strongly inhibit the CO2-sensitive neuron as candidates for use in disruption of host-seeking behaviour, as well as an odour that evokes CO2-like activity and thus has potential use as a lure in trapping devices. Analysis of responses to panels of structurally related odours across the three mosquitoes and Drosophila, which have related CO2-receptor proteins, reveals a pattern of inhibition that is often conserved. We use video tracking in wind-tunnel experiments to demonstrate that the novel ultra-prolonged activators can completely disrupt CO2-mediated activation as well as source-finding behaviour in Aedes mosquitoes, even after the odour is no longer present. Finally, semi-field studies demonstrate that use of ultra-prolonged activators disrupts CO2-mediated hut entry behaviour of Culex mosquitoes. The three classes of CO2 response modifying odours offer powerful instruments for developing new generations of insect repellents and lures, which even in small quantities can interfere with the ability of mosquitoes to seek humans.
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Affiliation(s)
- Stephanie Lynn Turner
- Cellular, Molecular, and Developmental Biology Program, University of California, Riverside, California 92521, USA
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11
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Molecular basis of odor coding in the malaria vector mosquito Anopheles gambiae. Proc Natl Acad Sci U S A 2010; 107:4418-23. [PMID: 20160092 DOI: 10.1073/pnas.0913392107] [Citation(s) in RCA: 277] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A systematic functional analysis across much of the conventional Anopheles gambiae odorant receptor (AgOR) repertoire was carried out in Xenopus oocytes using two-electrode, voltage-clamp electrophysiology. The resulting data indicate that each AgOR manifests a distinct odor-response profile and tuning breadth. The large diversity of tuning responses ranges from AgORs that are responsive to a single or small number of odorants (specialists) to more broadly tuned receptors (generalists). Several AgORs were identified that respond robustly to a range of human volatiles that may play a critical role in anopheline host selection. AgOR responses were analyzed further by constructing a multidimensional odor space representing the relationships between odorants and AgOR responses. Within this space, the distance between odorants is related to both chemical class and concentration and may correlate with olfactory discrimination. This study provides a comprehensive overview of olfactory coding mechanisms of An. gambiae that ultimately may aid in fostering the design and development of olfactory-based strategies for reducing the transmission of malaria and other mosquito-borne diseases.
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Cardé RT, Willis MA. Navigational strategies used by insects to find distant, wind-borne sources of odor. J Chem Ecol 2008; 34:854-66. [PMID: 18581182 DOI: 10.1007/s10886-008-9484-5] [Citation(s) in RCA: 251] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2008] [Revised: 02/24/2008] [Accepted: 04/23/2008] [Indexed: 10/21/2022]
Abstract
Insects locate many resources important to survival by tracking along wind-borne odor plumes to their source. It is well known that plumes are patchy distributions of high concentration packets of odor interspersed with clean air, not smooth Gaussian distributions of odor intensity. This realization has been crucial to our understanding of plume-tracking behavior, because insect locomotory movements and sensory processing typically take place in the range of tens to hundreds of milliseconds, permitting them to respond to the rapid changes in odor concentration they experience in plumes. Because odor plumes are not comprised of smooth concentration gradients, they cannot provide the directional information necessary to allow plume-tracking insects to steer toward the source. Many experiments have shown that, in the species examined, successful source location requires two sensory inputs: the presence of the attractive odor and the detection of the direction of the wind bearing that odor. All plume-tracking insects use the wind direction as the primary directional cue that enables them to steer their movements toward the odor source. Experimental manipulations of the presence and absence of the odor, and the presence, absence, or direction of the wind during plume tracking, have begun to resolve the relationship between these two sensory inputs and how they shape the maneuvers we observe. Experiments, especially those undertaken in the natural wind and odor environments of the organisms in question and those directed at understanding the neural processing that underlie plume tracking, promise to enhance our understanding of this remarkable behavior.
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Affiliation(s)
- Ring T Cardé
- Department of Entomology, University of California, Riverside, CA 92521, USA.
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Cayirlioglu P, Kadow IG, Zhan X, Okamura K, Suh GSB, Gunning D, Lai EC, Zipursky SL. Hybrid neurons in a microRNA mutant are putative evolutionary intermediates in insect CO2 sensory systems. Science 2008; 319:1256-60. [PMID: 18309086 PMCID: PMC2714168 DOI: 10.1126/science.1149483] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Carbon dioxide (CO2) elicits different olfactory behaviors across species. In Drosophila, neurons that detect CO2 are located in the antenna, form connections in a ventral glomerulus in the antennal lobe, and mediate avoidance. By contrast, in the mosquito these neurons are in the maxillary palps (MPs), connect to medial sites, and promote attraction. We found in Drosophila that loss of a microRNA, miR-279, leads to formation of CO2 neurons in the MPs. miR-279 acts through down-regulation of the transcription factor Nerfin-1. The ectopic neurons are hybrid cells. They express CO2 receptors and form connections characteristic of CO2 neurons, while exhibiting wiring and receptor characteristics of MP olfactory receptor neurons (ORNs). We propose that this hybrid ORN reveals a cellular intermediate in the evolution of species-specific behaviors elicited by CO2.
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Affiliation(s)
- Pelin Cayirlioglu
- Department of Biological Chemistry, Howard Hughes Medical Institute, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
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Ghaninia M, Ignell R, Hansson BS. Functional classification and central nervous projections of olfactory receptor neurons housed in antennal trichoid sensilla of female yellow fever mosquitoes, Aedes aegypti. Eur J Neurosci 2007; 26:1611-23. [PMID: 17880395 PMCID: PMC2121139 DOI: 10.1111/j.1460-9568.2007.05786.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Mosquitoes are highly dependent on their olfactory system for, e.g. host location and identification of nectar-feeding and oviposition sites. Odours are detected by olfactory receptor neurons (ORNs) housed in hair-shaped structures, sensilla, on the antennae and maxillary palps. In order to unravel the function of the olfactory system in the yellow fever vector, Aedes aegypti, we performed single-sensillum recordings from trichoid sensilla on female antennae. These sensilla are divided into four distinct morphological types. Based on the response to a set of 16 odour compounds, we identified 18 different ORN types, housed in 10 sensillum types. The ORNs responded to behaviourally relevant olfactory cues, such as oviposition attractants and sweat-borne compounds, including 4-methylcyclohexanol and indole, respectively. Two ORNs housed in these sensilla, as well as two ORNs housed in an additional sensillum type, did not respond to any of the compounds tested. The ORNs housed in individual sensilla exhibited stereotypical pairing and displayed differences in signalling mode (excitatory and inhibitory) as well as in temporal response patterns. In addition to physiological characterization, we performed anterograde neurobiotin stainings of functionally identified ORNs in order to define the functional map among olfactory glomeruli in the primary olfactory centre, the antennal lobe. The targeted glomeruli were compared with an established 3D map. Our data showed that the ORN types sent their axons to defined antennal lobe glomeruli in a stereotypic pattern.
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Affiliation(s)
- Majid Ghaninia
- Division of Chemical Ecology, Department of Plant Protection Biology, SLU, Box 44, 230 53, Alnarp, Sweden
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15
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Lu T, Qiu YT, Wang G, Kwon JY, Rutzler M, Kwon HW, Pitts RJ, van Loon JJ, Takken W, Carlson JR, Zwiebel LJ. Odor coding in the maxillary palp of the malaria vector mosquito Anopheles gambiae. Curr Biol 2007; 17:1533-44. [PMID: 17764944 PMCID: PMC3113458 DOI: 10.1016/j.cub.2007.07.062] [Citation(s) in RCA: 242] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2007] [Revised: 07/27/2007] [Accepted: 07/30/2007] [Indexed: 11/25/2022]
Abstract
BACKGROUND Many species of mosquitoes, including the major malaria vector Anopheles gambiae, utilize carbon dioxide (CO(2)) and 1-octen-3-ol as olfactory cues in host-seeking behaviors that underlie their vectorial capacity. However, the molecular and cellular basis of such olfactory responses remains largely unknown. RESULTS Here, we use molecular and physiological approaches coupled with systematic functional analyses to define the complete olfactory sensory map of the An. gambiae maxillary palp, an olfactory appendage that mediates the detection of these compounds. In doing so, we identify three olfactory receptor neurons (ORNs) that are organized in stereotyped triads within the maxillary-palp capitate-peg-sensillum population. One ORN is CO(2)-responsive and characterized by the coexpression of three receptors that confer CO(2) responses, whereas the other ORNs express characteristic odorant receptors (AgORs) that are responsible for their in vivo olfactory responses. CONCLUSIONS Our results describe a complete and highly concordant map of both the molecular and cellular olfactory components on the maxillary palp of the adult female An. gambiae mosquito. These results also facilitate the understanding of how An. gambiae mosquitoes sense olfactory cues that might be exploited to compromise their ability to transmit malaria.
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Affiliation(s)
- Tan Lu
- Department of Biological Sciences, Center for Molecular Neuroscience, Institute of Chemical Biology and Global Health, and Program in Developmental Biology, Vanderbilt University, Nashville, Tennessee 37235
| | - Yu Tong Qiu
- Laboratory of Entomology, Wageningen University, P.O. Box 8031, 6700 EH Wageningen, The Netherlands
| | - Guirong Wang
- Department of Biological Sciences, Center for Molecular Neuroscience, Institute of Chemical Biology and Global Health, and Program in Developmental Biology, Vanderbilt University, Nashville, Tennessee 37235
| | - Jae Young Kwon
- Department of Molecular, Cellular, and Developmental, Biology, Yale University, New Haven, Connecticut 06520-8103
| | - Michael Rutzler
- Department of Biological Sciences, Center for Molecular Neuroscience, Institute of Chemical Biology and Global Health, and Program in Developmental Biology, Vanderbilt University, Nashville, Tennessee 37235
| | - Hyung-Wook Kwon
- Department of Biological Sciences, Center for Molecular Neuroscience, Institute of Chemical Biology and Global Health, and Program in Developmental Biology, Vanderbilt University, Nashville, Tennessee 37235
| | - R. Jason Pitts
- Department of Biological Sciences, Center for Molecular Neuroscience, Institute of Chemical Biology and Global Health, and Program in Developmental Biology, Vanderbilt University, Nashville, Tennessee 37235
| | - Joop J.A. van Loon
- Laboratory of Entomology, Wageningen University, P.O. Box 8031, 6700 EH Wageningen, The Netherlands
| | - Willem Takken
- Laboratory of Entomology, Wageningen University, P.O. Box 8031, 6700 EH Wageningen, The Netherlands
| | - John R. Carlson
- Department of Molecular, Cellular, and Developmental, Biology, Yale University, New Haven, Connecticut 06520-8103
| | - Laurence J. Zwiebel
- Department of Biological Sciences, Center for Molecular Neuroscience, Institute of Chemical Biology and Global Health, and Program in Developmental Biology, Vanderbilt University, Nashville, Tennessee 37235
- Correspondence:
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Guerenstein PG, Christensen TA, Hildebrand JG. Sensory processing of ambient CO2 information in the brain of the moth Manduca sexta. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2004; 190:707-25. [PMID: 15235811 DOI: 10.1007/s00359-004-0529-0] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2003] [Revised: 04/23/2004] [Accepted: 04/24/2004] [Indexed: 11/26/2022]
Abstract
Insects use information about CO2 to perform vital tasks such as locating food sources. In certain moths, CO2 is involved in oviposition behavior. The labial palps of adult moths that feed as adults have a pit organ containing sensory receptor cells that project into the antennal lobes, the sites of primary processing of olfactory information in the brain. In the moth Manduca sexta and certain other species of Lepidoptera, these receptor cells in the labial-palp pit organ have been shown to be tuned to CO2, and their axons project to a single, identified glomerulus in the antennal lobe, the labial-palp pit organ glomerulus. At present, however, nothing is known about the function of this glomerulus or how CO2 information is processed centrally. We used intracellular recording and staining to reveal projection (output) neurons in the antennal lobes that respond to CO2 and innervate the labial-palp pit organ glomerulus. Our results demonstrate that this glomerulus is the site of first-order processing of sensory information about ambient CO2. We found three functional types of CO2-responsive neurons (with their cell bodies in the antennal lobe or the protocerebrum) that provide output from the antennal lobe to higher centers in the brain. Some physiological characteristics of those neurons are described.
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Affiliation(s)
- Pablo G Guerenstein
- Arizona Research Laboratories, Division of Neurobiology, University of Arizona, PO Box 210077, Tucson, AZ 85721-0077, USA
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