Females of the Southern House mosquito, Culex quinquefasciatus, rely on environmental cues, also known as oviposition attractants (OAs), to locate suitable sites for laying eggs. Their antennae are endowed with hair-like structures called sensilla. We have already identified three types of sensilla on the antennae of the Southern House mosquito that detect OAs. This research is aimed at testing the hypothesis that both odorant-binding proteins (OBPs) and odorant receptors (ORs), which are harbored in these sensilla, are essential for reception of OAs. Affinity of OBPs mined from the Culex genome towards a small set of known OAs will be measured. Function of OBPs with high affinity for OAs will be further evaluated by RNAi and electrophysiology to unambiguously identify those involved in OA reception. Candidate ORs identified from the genome will be expressed in the Xenopus oocyte system and tested against a panel of odorants, which include known OAs. A comparison of their response profiles with the profiles obtained from the mosquito antennae in our preliminary studies will allow identification of receptors and their localization in the OA-detecting sensilla. The olfactory proteins involved in OA reception will be used to screen a library of natural products to prospect for a second generation of OAs. Compounds already identified in preliminary studies and those derived from the above-mentioned molecular approaches will be tested by indoor behavioral studies and ultimately in the field. That way we plan to develop better OAs for monitoring and surveillance as well as to pave the way for novel environmentally friendly strategies for controlling Culex mosquito populations.

Public Health Relevance

Mosquitoes in the genus Culex are vectors of pathogens causing human diseases throughout the world, including filariasis, various types of encephalitis, and in the United States they spread West Nile Virus while feeding on birds and humans. Vector surveillance and monitoring of Culex populations are reliant on chemical cues to attract gravid females searching for oviposition sites, but current trapping technologies need improvements, particularly the development of better oviposition attractants (OAs). This research is aimed at advancing our knowledge of mosquito olfaction as well as to develop a second generation of OAs, which may be used for trapping, surveillance and possibly green chemistry for controlling mosquito populations.

National Institute of Health (NIH)
National Institute of Allergy and Infectious Diseases (NIAID)
Research Project (R01)
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Vector Biology Study Section (VB)
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Costero, Adriana
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University of California Davis
Schools of Earth Sciences/Natur
United States
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Franco, Thiago A; Xu, Pingxi; Brito, Nathália F et al. (2018) Reverse chemical ecology-based approach leading to the accidental discovery of repellents for Rhodnius prolixus, a vector of Chagas diseases refractory to DEET. Insect Biochem Mol Biol 103:46-52
Choo, Young-Moo; Xu, Pingxi; Hwang, Justin K et al. (2018) Reverse chemical ecology approach for the identification of an oviposition attractant for Culex quinquefasciatus. Proc Natl Acad Sci U S A 115:714-719
Leal, Walter S (2017) Reverse chemical ecology at the service of conservation biology. Proc Natl Acad Sci U S A 114:12094-12096
Guedes, Duschinka Rd; Paiva, Marcelo Hs; Donato, Mariana Ma et al. (2017) Zika virus replication in the mosquito Culex quinquefasciatus in Brazil. Emerg Microbes Infect 6:e69
Leal, Walter S; Barbosa, Rosângela M R; Zeng, Fangfang et al. (2017) Does Zika virus infection affect mosquito response to repellents? Sci Rep 7:42826
Lu, WeiYu; Hwang, Justin K; Zeng, Fangfang et al. (2017) DEET as a feeding deterrent. PLoS One 12:e0189243
Paiva, Marcelo Henrique Santos; Guedes, Duschinka Ribeiro Duarte; Leal, Walter Soares et al. (2017) Sensitivity of RT-PCR method in samples shown to be positive for Zika virus by RT-qPCR in vector competence studies. Genet Mol Biol 40:597-599
Hughes, David T; Pelletier, Julien; Rahman, Suhaila et al. (2017) Functional and Nonfunctional Forms of CquiOR91, an Odorant Selectivity Subunit of Culex quinquefasciatus. Chem Senses 42:333-341
Pelletier, Julien; Xu, Pingxi; Yoon, Kyong S et al. (2015) Odorant receptor-based discovery of natural repellents of human lice. Insect Biochem Mol Biol 66:103-9
Yin, Jiao; Choo, Young-Moo; Duan, Hongxia et al. (2015) Selectivity of odorant-binding proteins from the southern house mosquito tested against physiologically relevant ligands. Front Physiol 6:56

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