Reverse and conventional chemical ecology in culex mosquitoes

Walter S. Leal, Rosângela M.R. Barbosa, Wei Xu, Yuko Ishida, Zainulabeuddin Syed, Nicolas Latte, Angela M. Chen, Tania I. Morgan, Anthony J. Cornel, André Furtado

Research output: Chapter in Book/Report/Conference proceedingChapterpeer-review

Abstract

Synthetic mosquito oviposition attractants are sorely needed for surveillance and control programs for Culex species, which are major vectors of pathogens causing various human diseases, including filariasis, encephalitis, and West Nile encephalomyelitis. We employed novel and conventional chemical ecology approaches to identify potential attractants, which were demonstrated in field tests to be effective for monitoring populations of Cx. p. quinquefasciatus in human dwellings. Immunohistochemistry (IHC) studies showed that an odorant-binding protein (OBP) from this species, CquiOBP1, is expressed in trichoid sensilla on the antennae, including short, sharp-tipped trichoid sensilla type, which house an olfactory receptor neuron sensitive to a previously identified mosquito oviposition pheromone (MOP), 6-acetoxy-5-hexadecanolide. The CquiOBP1 exists in monomeric and dimeric forms. Monomeric CquiOBP1 bound MOP in a pH-dependent manner, with a change in secondary structure apparently related to the loss of binding at low pH. The pheromone antipode showed higher affinity than the natural stereoisomer. By using both CquiOBP1 as a molecular target in binding assays and gas chromatography-electroantennographic detection (GCEAD), we identified nonanal, trimethylamine (TMA), and skatole as test compounds. Extensive field evaluations in Recife, Brazil, a region with high populations of Cx. p. quinquefasciatus, showed that a combination of TMA (0.9 μg/l) and nonanal (0.15 ng/ μl) is equivalent in attraction to the currently used infusion-based lure, and superior in that the offensive smell of infusions was eliminated in the newly developed synthetic mixture.

Original languageEnglish
Title of host publicationEnvironmental Chemistry
Subtitle of host publicationNew Techniques and Data
Pages132-149
Number of pages18
ISBN (Electronic)9781466558496
StatePublished - Jan 1 2011

Bibliographical note

Publisher Copyright:
© 2012 by Apple Academic Press, Inc.

Keywords

  • CquiOBP1
  • Culex
  • Gas chromatography-electroantennographic detection
  • Immunohistochemistry liquid chromatography-electrospray ionization mass spectrometry
  • Odorant-binding protein
  • Sensilla

ASJC Scopus subject areas

  • General Chemistry

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