Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
PLoS One
2017 Jan 01;125:e0177454. doi: 10.1371/journal.pone.0177454.
Show Gene links
Show Anatomy links
Inhibition of insect olfactory behavior by an airborne antagonist of the insect odorant receptor co-receptor subunit.
Kepchia D
,
Moliver S
,
Chohan K
,
Phillips C
,
Luetje CW
.
???displayArticle.abstract???
Response to volatile environmental chemosensory cues is essential for insect survival. The odorant receptor (OR) family is an important class of receptors that detects volatile molecules; guiding insects towards food, mates, and oviposition sites. ORs are odorant-gated ion channels, consisting of a variable odorant specificity subunit and a conserved odorant receptor co-receptor (Orco) subunit, in an unknown stoichiometry. The Orco subunit possesses an allosteric site to which modulators can bind and noncompetitively inhibit odorant activation of ORs. In this study, we characterized several halogen-substituted versions of a phenylthiophenecarboxamide Orco antagonist structure. Orco antagonist activity was assessed on ORs from Drosophila melanogaster flies and Culex quinquefasciatus mosquitoes, expressed in Xenopus laevis oocytes and assayed by two-electrode voltage clamp electrophysiology. One compound, OX1w, was also shown to inhibit odorant activation of a panel of Anopheles gambiae mosquito ORs activated by diverse odorants. Next, we asked whether Orco antagonist OX1w could affect insect olfactory behavior. A Drosophila melanogaster larval chemotaxis assay was utilized to address this question. Larvae were robustly attracted to highly diluted ethyl acetate in a closed experimental chamber. Attraction to ethyl acetate was Orco dependent and also required the odorant specificity subunit Or42b. The addition of the airborne Orco antagonist OX1w to the experimental chamber abolished larval chemotaxis towards ethyl acetate. The Orco antagonist was not a general inhibitor of sensory behavior, as behavioral repulsion from a light source was unaffected. This is the first demonstration that an airborne Orco antagonist can alter olfactory behavior in an insect. These results suggest a new approach to insect control and emphasize the need to develop more potent Orco antagonists.
???displayArticle.pubmedLink???
28562598
???displayArticle.pmcLink???PMC5451006 ???displayArticle.link???PLoS One ???displayArticle.grants???[+]
Fig 1. Orco antagonist activity of phenylthiophenecarboxamide compounds OX1t-OX1w.Compounds were initially screened at 100 μM against ORs from Drosophila melanogaster (Dmel\Orco+Dmel\OR35a activated by 10 μM OLC12) and Culex quinquefasciatus (Cqui\Orco+Cqui\OR21 activated by 3 μM OLC12). Concentration-inhibition curves were constructed for compounds that displayed favorable antagonist activity at both receptors. OX1a (a previously identified Orco antagonist [49]) served as a reference compound. Data are presented as mean ± SEM (n = 3–11). nd, not determined.
Fig 2. Orco antagonist OX1w inhibits odorant activation of a diverse array of ORs.(A) OX1w inhibits odorant activation of ORs from D. melanogaster and A. gambiae. Top trace, an oocyte expressing Dmel\Orco+Dmel\Or35a was challenged with a 30 sec application of 1 μM hexanol (Hex). After a 20 min wash period, 100 μM OX1w was applied for 90 sec before a second application of Hex and coapplied during the Hex application. Bottom trace, an oocyte expressing Agam\Orco+Agam\Or28 was challenged with a 30 sec application of 40 μM acetophenone (Ace). After a 20 min wash period, 100 μM OX1w was applied for 90 sec before a second application of Ace and coapplied during the Ace application. (B) Oocytes expressing a variety of ORs were activated by the appropriate odorant and tested for inhibition by OX1w as in panel A. Dmel\Orco+Dmel\Or35a was activated by 1 μM hexanol, Agam\Orco+Agam\Or15 was activated by 18 μM acetophenone, Agam\Orco+Agam\Or27 was activated by 3 μM L-fenchone, Agam\Orco+Agam\Or28 was activated by 40 μM acetophenone, Agam\Orco+Agam\Or31 was activated by 70 μM geranyl acetate, Agam\Orco+Agam\Or39 was activated by 10 μM 6-methyl-5-hepten-2-one, and Agam\Orco+Agam\Or65 was activated by 100 nM eugenol. Inhibition values were normalized to the value obtained when the assay was run in the absence of OX1w (sham). The structure of each odorant is shown. Data are presented as mean ± SEM (n = 3–8).
Fig 3. D. melanogaster larvae are attracted to ethyl acetate (EA).(A) Diagram of larval plate assay. A starting circle was drawn at the center of a 100x15 mm polystyrene Petri dish (VWR) containing 20 ml of 1.1% agarose. A line divides the plate in half, with a small filter disk on each side. A Response Index (RI) is calculated as RI = (S − C)/(S + C), where S = number of larvae on the stimulus (EA) side and C = number of larvae on the control (vehicle) side. RI = 1 would indicate complete attraction, RI = 0 would indicate no preference, and RI = -1 would indicate complete repulsion. (B) Left panel, at the start of an experiment, larvae are in the starting circle flanked on either side by small filter disks. 10 μL of 1:1000 diluted EA was placed on the left filter disk and 10 μL of mineral oil (vehicle) was placed on the right filter disk. Right panel, the same plate, following a 5 min migration period. The majority of larvae have moved towards the filter disk containing EA. A large group of larvae is indicated by the arrow. (C) Larval chemotaxis towards EA is assayed at a series of dilutions. Data are presented as mean ± SEM (n = 4–7).
Fig 4. Ethyl acetate attraction is inhibited by an airborne Orco antagonist.(A) Cross-section diagram of the larval plate assay with the addition of a large filter paper on the inner side of the lid. (B) Results of the larval chemotaxis assay. EA, ethyl acetate; oil, mineral oil (vehicle); D, DMSO (vehicle); OX1w, Orco antagonist; Ø, nothing added; light, fiber optic light source. Data are presented as mean ± SEM (n = 4–9). Results were compared by one-way ANOVA and Bonferroni’s multiple comparison test: for comparison to oil vs. oil control (sixth bar from top), **, p<0.01; ***, p<0.001. Light repulsion (bottom 2 bars) with DMSO or OX1w in the lid filter was compared by two-tailed, unpaired t-test. (C) A representative OX1w inhibition experiment. In both panels, larvae were placed in the starting circle, flanked on the left by EA and on the right by mineral oil (vehicle). In the left panel, DMSO (vehicle) was applied to the lid filter paper, while in the right panel, OX1w was applied to the lid filter paper. A large group of larvae is indicated by the arrow. (D) Cross-section diagram of the larval plate assay with addition of a fiber optic light source.
Abuin,
Functional architecture of olfactory ionotropic glutamate receptors.
2011, Pubmed
Abuin,
Functional architecture of olfactory ionotropic glutamate receptors.
2011,
Pubmed
Benton,
Atypical membrane topology and heteromeric function of Drosophila odorant receptors in vivo.
2006,
Pubmed
Benton,
Variant ionotropic glutamate receptors as chemosensory receptors in Drosophila.
2009,
Pubmed
Carey,
Insect olfaction from model systems to disease control.
2011,
Pubmed
Carey,
Odorant reception in the malaria mosquito Anopheles gambiae.
2010,
Pubmed
Chen,
Identification of new agonists and antagonists of the insect odorant receptor co-receptor subunit.
2012,
Pubmed
,
Xenbase
Chen,
Phenylthiophenecarboxamide antagonists of the olfactory receptor co-receptor subunit from a mosquito.
2013,
Pubmed
,
Xenbase
Chen,
Trace amines inhibit insect odorant receptor function through antagonism of the co-receptor subunit.
2014,
Pubmed
DeGennaro,
The mysterious multi-modal repellency of DEET.
2015,
Pubmed
DeGennaro,
orco mutant mosquitoes lose strong preference for humans and are not repelled by volatile DEET.
2013,
Pubmed
Dweck,
Olfactory proxy detection of dietary antioxidants in Drosophila.
2015,
Pubmed
Fox,
Candidate odorant receptors from the malaria vector mosquito Anopheles gambiae and evidence of down-regulation in response to blood feeding.
2001,
Pubmed
Franco,
Silencing the odorant receptor co-receptor RproOrco affects the physiology and behavior of the Chagas disease vector Rhodnius prolixus.
2016,
Pubmed
Gibson,
Visual and olfactory responses of haematophagous Diptera to host stimuli.
1999,
Pubmed
Hallem,
The molecular basis of odor coding in the Drosophila antenna.
2004,
Pubmed
Hallem,
Coding of odors by a receptor repertoire.
2006,
Pubmed
Hughes,
Odorant receptor from the southern house mosquito narrowly tuned to the oviposition attractant skatole.
2010,
Pubmed
,
Xenbase
Jones,
Functional conservation of an insect odorant receptor gene across 250 million years of evolution.
2005,
Pubmed
Jones,
Functional agonism of insect odorant receptor ion channels.
2011,
Pubmed
Jones,
Allosteric antagonism of insect odorant receptor ion channels.
2012,
Pubmed
Kepchia,
Correction: Inhibition of insect olfactory behavior by an airborne antagonist of the insect odorant receptor co-receptor subunit.
2017,
Pubmed
Kreher,
Translation of sensory input into behavioral output via an olfactory system.
2008,
Pubmed
Krieger,
A candidate olfactory receptor subtype highly conserved across different insect orders.
2003,
Pubmed
Larsson,
Or83b encodes a broadly expressed odorant receptor essential for Drosophila olfaction.
2004,
Pubmed
Leal,
The enigmatic reception of DEET - the gold standard of insect repellents.
2014,
Pubmed
Leal,
Differential expression of olfactory genes in the southern house mosquito and insights into unique odorant receptor gene isoforms.
2013,
Pubmed
Lee,
Avoiding DEET through insect gustatory receptors.
2010,
Pubmed
Li,
CRISPR/Cas9 in locusts: Successful establishment of an olfactory deficiency line by targeting the mutagenesis of an odorant receptor co-receptor (Orco).
2016,
Pubmed
Liman,
Subunit stoichiometry of a mammalian K+ channel determined by construction of multimeric cDNAs.
1992,
Pubmed
,
Xenbase
Monte,
Characterization of the larval olfactory response in Drosophila and its genetic basis.
1989,
Pubmed
Nakagawa,
Amino acid residues contributing to function of the heteromeric insect olfactory receptor complex.
2012,
Pubmed
,
Xenbase
Nakagawa,
Insect sex-pheromone signals mediated by specific combinations of olfactory receptors.
2005,
Pubmed
,
Xenbase
Nakagawa,
Controversy and consensus: noncanonical signaling mechanisms in the insect olfactory system.
2009,
Pubmed
Neuhaus,
Odorant receptor heterodimerization in the olfactory system of Drosophila melanogaster.
2005,
Pubmed
Nichols,
Subunit contributions to insect olfactory receptor function: channel block and odorant recognition.
2011,
Pubmed
,
Xenbase
Nichols,
Transmembrane segment 3 of Drosophila melanogaster odorant receptor subunit 85b contributes to ligand-receptor interactions.
2010,
Pubmed
,
Xenbase
Pask,
Heteromeric Anopheline odorant receptors exhibit distinct channel properties.
2011,
Pubmed
Pellegrino,
A natural polymorphism alters odour and DEET sensitivity in an insect odorant receptor.
2011,
Pubmed
Pelletier,
An odorant receptor from the southern house mosquito Culex pipiens quinquefasciatus sensitive to oviposition attractants.
2010,
Pubmed
,
Xenbase
Pickett,
Chemical ecology of animal and human pathogen vectors in a changing global climate.
2010,
Pubmed
Pitts,
A highly conserved candidate chemoreceptor expressed in both olfactory and gustatory tissues in the malaria vector Anopheles gambiae.
2004,
Pubmed
Ramdya,
Evolving olfactory systems on the fly.
2010,
Pubmed
Sato,
Insect olfactory receptors are heteromeric ligand-gated ion channels.
2008,
Pubmed
,
Xenbase
Sawin-McCormack,
Characterization and genetic analysis of Drosophila melanogaster photobehavior during larval development.
1995,
Pubmed
Siju,
Influence of blood meal on the responsiveness of olfactory receptor neurons in antennal sensilla trichodea of the yellow fever mosquito, Aedes aegypti.
2010,
Pubmed
Smallegange,
Malaria infected mosquitoes express enhanced attraction to human odor.
2013,
Pubmed
Sparks,
Bitter-sensitive gustatory receptor neuron responds to chemically diverse insect repellents in the common malaria mosquito Anopheles quadrimaculatus.
2016,
Pubmed
Stanczyk,
Aedes aegypti mosquitoes exhibit decreased repellency by DEET following previous exposure.
2013,
Pubmed
Stensmyr,
A conserved dedicated olfactory circuit for detecting harmful microbes in Drosophila.
2012,
Pubmed
Sutherland,
A horizon scan of global conservation issues for 2015.
2015,
Pubmed
Takken,
Inhibition of host-seeking response and olfactory responsiveness in Anopheles gambiae following blood feeding.
2001,
Pubmed
Taylor,
Structure-activity relationship of a broad-spectrum insect odorant receptor agonist.
2012,
Pubmed
Tsitoura,
Inhibition of Anopheles gambiae odorant receptor function by mosquito repellents.
2015,
Pubmed
Tsitoura,
Expression and membrane topology of Anopheles gambiae odorant receptors in lepidopteran insect cells.
2010,
Pubmed
Vosshall,
A unified nomenclature system for the insect olfactory coreceptor.
2011,
Pubmed
Vosshall,
Molecular architecture of smell and taste in Drosophila.
2007,
Pubmed
Wang,
Molecular basis of odor coding in the malaria vector mosquito Anopheles gambiae.
2010,
Pubmed
,
Xenbase
Wanner,
A honey bee odorant receptor for the queen substance 9-oxo-2-decenoic acid.
2007,
Pubmed
,
Xenbase
Wicher,
Drosophila odorant receptors are both ligand-gated and cyclic-nucleotide-activated cation channels.
2008,
Pubmed
Xia,
The molecular and cellular basis of olfactory-driven behavior in Anopheles gambiae larvae.
2008,
Pubmed
,
Xenbase
Xu,
Mosquito odorant receptor for DEET and methyl jasmonate.
2014,
Pubmed
,
Xenbase