Walter Leal

image of Walter Leal

Professor of Biochemistry


Molecular & Cellular Biology

Offices and Labs

1117 Surge III


1990 PhD Biochemistry Tsukuba University, Tsukuba-Ibaraki, Japan -
1987 MS Agricultural Chemistry Mie University, Tsu-Mie, Japan
1982 BS Chemical Engineering Universidade Federal de Pernambuco, Recife-PE, Brazil

Research Interests

Research in my lab is aimed at unraveling the molecular mechanisms that make the insect’s olfactory system so sensitive and selective. Insect prominence among other animals is due in large part to a key physiological element for their survival and reproduction - a refined olfactory system. Olfaction is orchestrated at various levels starting with reception of odorants at the periphery, processing and integration of olfactory and other sensory modalities in the brain, and ultimately translation of olfactory signal into behavior. Thus, the cornerstone of a sophisticated olfactory system is the ability of the insect’s peripheral system to selectively detect and rapidly inactivate minute amounts of odorants. Reception of odorants is mainly mediated by three olfactory proteins, namely, odorant-binding proteins (OBPs), odorant receptors (ORs), and odorant-degrading enzymes (ODEs). OBPs are involved in the uptake, transport and delivery of odorants to ORs. By using biochemical, electrophysiological, RNAi, and kinetic studies we have demonstrated that OBPs are essential for the sensitivity of moth’s olfactory system. In collaborations with structural biologists, including UC Davis colleagues, we study the molecular mechanisms of odorant binding, release, and transport, including novel, pH-dependent conformational changes in moths and mosquitoes. By comparative kinetic studies of odorant degradation by recombinant and native enzymes we have demonstrated for the first time that ODEs are involved in the fast inactivation of odorants. Using bioinformatics and molecular approaches coupled with the Xenopus oocyte recording system we investigate how ORs contribute to the selectivity of the insect’s olfactory system.


2012 Elected, Brazilian Academy of Sciences
2012, Selected-Silver Medal, International Society of Chemical Ecology
2011 Fellow, Royal Entomological Society
2011 Nan Yao Su Award for Innovation and Creativity in Entomology, Entomological Society of America (ESA)
2011 Sawicki Lecture Honored Speaker, Rothamsted Research, United Kingdom
2010 Guest Speaker, American Philosophical Society (Autumn Meeting)
2010 Theodore L. Hopkins Distinguished Colloquium, Kansas State University
2010 C. W. Woodworth Award, ESA-Pacific Branch
2009 Fellow, Entomological Society of America (ESA)
2008 Medal of Science “Mérito em Ciência,” Brazilian Society of Entomology
2007 Silverstein-Simeone Award, International Society of Chemical Ecology
2006 Scudder Lecture Award, University of British Columbia, Canada
2005 Fellow, American Association for the Advancement of Science (AAAS)
2002 Recognition Award in Insect Physiology, Biochemistry, and Toxicology, ESA-Pacific Branch
1998 Award of the Japanese Society of Applied Entomology and Zoology (Equivalent to ESA Fellow in the US)
1997-1999 Bio-Oriented Technology Research Advancement Institution, Fellowship
1995-1997 Science and Technology Agency, Fellowship
1995 Medal of Achievement, Entomological Society of Brazil
1994 Technology Prize (Gijitsusho), Japan Society for Bioscience, Biotech. & Agrochemistry

Department and Center Affiliations

Department of Molecular and Cellular Biology


Entomological Society of America; International Society for Chemical Ecology; Japan Society for Bioscience, Biotechnology, and Agrochemistry; Japan Society of Applied Entomology and Zoology
American Association for the Advancement of Science (AAAS)
American Chemical Society
Royal Entomological Society

CBS Grad Group Affiliations

Biochemistry, Molecular, Cellular and Developmental Biology

Graduate Groups not Housed in CBS

AgCHEM: Agricultural & Environmental Chemistry


Leal Lab website
  • Pingxi Xu, Young-Moo Choo, Mario Izidoro, Yinliang Wang, Alyssa De la Rosa, Cherre Sade, Jiao Yin, Steve Shamoo

Teaching Interests



BIS 102 Struc-Func Biomolecules


12/16/2013 8:25:25 AM
  • Xu, P., Choo, Y. M., De La Rosa, Alyssa, and Leal, W. S. Mosquito odorant receptor for DEET and methyl jasmonate Proc. Natl. Acad. Sci. USA, October 27, 2014, doi: 10.1073/pnas.1417244111 

  • Leal, W. S., Choo, Y. M., Xu, P., da Silva, C. B., and Ueira-Vieira, C. Differential expression of olfactory genes in the southern house mosquito and insights into unique odorant receptor gene isoforms Proc. Natl. Acad. Sci. USA, October 28, 2013, doi: 10.1073/pnas.1316059110
  • Leal, W. S. Healing power of honey. Proc. Natl. Acad. Sci. USA May 28, 2013 vol. 110 no. 22 8763-8764
  • Damberger,F. D., Michel, E., Ishida, Y., Leal, W. S., and Wüthrich, K. 2013 Pheromone discrimination by a pH-tuned polymorphism of the Bombyx mori pheromone-binding protein Proc. Natl. Acad. Sci. USA, October 24, 2013, doi: 10.1073/pnas.1317706110
  • Zhu F, Xu P, Barbosa RM, Choo YM, Leal WS. RNAi-based demonstration of direct link between specific odorant receptors and mosquito oviposition behavior. Insect Biochem Mol Biol. 2013 Oct;43(10):916-23. doi: 10.1016/j.ibmb.2013.07.008. Epub 2013 Aug 2. PubMed PMID: 23911547.
  • Xu P, Leal WS. Probing insect odorant receptors with their cognate ligands: insights into structural features. Biochem Biophys Res Commun. 2013 Jun 7;435(3):477-82. doi: 10.1016/j.bbrc.2013.05.015. Epub 2013 May 11. PubMed PMID: 23673297
  • Xu P, Choo YM, Pelletier J, Sujimoto FR, Hughes DT, Zhu F, Atungulu E, Cornel AJ, Luetje CW, Leal WS. Silent, generic and plant kairomone sensitive odorant receptors from the Southern house mosquito. J Insect Physiol. 2013 Sep;59(9):961-6. doi: 10.1016/j.jinsphys.2013.07.004. Epub 2013 Jul 19. PubMed PMID: 23876610.
  • Leal WS. Odorant reception in insects: roles of receptors, binding proteins, and degrading enzymes. Annu Rev Entomol. 2013;58:373-91. doi: 10.1146/annurev-ento-120811-153635. Epub 2012 Sep 27. Review. PubMed PMID: 23020622
  • Xu P, Garczynski SF, Atungulu E, Syed Z, Choo YM, Vidal DM, Zitelli CH, Leal WS. Moth sex pheromone receptors and deceitful parapheromones. PLoS One. 2012;7(7):e41653. doi: 10.1371/journal.pone.0041653. Epub 2012 Jul 20. PubMed PMID: 22911835; PubMed Central PMCID: PMC3401280.
  • Xu P, Hooper AM, Pickett JA, Leal WS. Specificity determinants of the silkworm moth sex pheromone. PLoS One. 2012;7(9):e44190. doi: 10.1371/journal.pone.0044190. Epub 2012 Sep 5. PubMed PMID: 22957053; PubMed Central PMCID: PMC3434217
  • Eliyahua, D., S. Nojimaa, R. G. Santangelo, S. Carpenterc, F. X. Webster, D. J. Kiemle, C. Gemeno, W. S. Leal, and Coby Schal. 2012. Unusual macrocyclic lactone sex pheromone of Parcoblatta lata, a primary food source of the endangered red-cockaded woodpecker. Proc. Natl. Acad. Sci. USA, doi: 10.1073/pnas.1111748109
  • Syed, Z., and W. S. Leal. 2011. Electrophysiological measurements from a moth olfactory system. J. Vis. Exp., doi: 10.3791/2489, 2011
  • E. Michel, F. F. Damberger, Y. Ishida, F. Fiorito, D. Lee, W. S. Leal, and K. Wuthrich. 2011. Dynamic conformational equilibria in the physiological function of the Bombyx mori pheromone-binding protein. J. Mol. Biol.,vol. 408, pp.922-931,,doi:10.1016/j.jmb.2011.03.008
  • Mao, Y., X. Xu, W. Xu, Y. Ishida, W. S. Leal, J. B. Ames, and J. Clardy. 2010. Crystal and solution structures of an odorant-binding protein from the southern house mosquito complexed with an oviposition pheromone. Proc. Natl. Acad. Sci. USA, doi: 10.1073/pnas.1012274107
  • Leal WS. Behavioural neurobiology: The treacherous scent of a human. Nature. 2010 Mar 4;464(7285):37-8. doi: 10.1038/464037a. PubMed PMID: 20203594
  • Syed, Z., A. Kopp, D. A. Kimbrell, and W. S. Leal. 2010. Bombykol receptors in the silkworm moth and the fruit fly. Proc. Natl. Acad. Sci. USA, vol. 107, pp. 9436-9439, 2010.
  • Syed, Z., and W. S. Leal. 2009. Acute olfactory response of Culex mosquitoes to a human- and bird-derived attractant. Proc. Natl. Acad. Sci. USA, vol. 106, pp. 18803-18808, 2009.
  • Syed, Z. and W. S. Leal. 2008. Mosquitoes smell and avoid the insect repellent DEET. Proc. Natl. Acad. Sci. USA, 105:13598-13603.
  • Wogulis, M., T. I. Morgan, Y. Ishida, W. S. Leal, and D. K. Wilson. The crystal structure of an odorant binding protein from Anopheles gambiae: Evidence for a common ligand release mechanism. Biochem. Biophys. Res. Commun. 339: 157-164, 2006.
  • Leal, W. S., R. M. R. Barbosa, W. Xu, Y. Ishida, Z. Syed, N. Latte, A. M. Chen, T. I. Morgan, A. J. Cornel, and A. Furtado. 2008. Reverse and conventional chemical ecology approaches for the development of oviposition attractants for Culex mosquitoes. PLoS ONE, 3(8): e3045. doi:10.1371/journal.pone.0003045.
  • Ishida, Y. and W. S. Leal. 2008. Chiral discrimination of the Japanese beetle sex pheromone and a behavioral antagonist by a pheromone-degrading enzyme. Proc. Natl. Acad. Sci. USA 105: 9076-9080.
  • Syed, Z., and W. S. Leal. 2007. Maxillary Palps Are Broad Spectrum Odorant Detectors in Culex quinquefasciatus. Chem. Senses 32:727–738.
  • Syed, Z., Y. Ishida, K. Taylor, D. A. Kimbrell and W. S. Leal. 2006. Pheromone reception in fruit flies expressing a moth’s odorant receptor. Proc. Natl. Acad. Sci. USA 103:16538-16543.
  • Ishida, Y. and W. S. Leal. 2005. Rapid inactivation of a moth pheromone. Proc. Natl. Acad. Sci. USA 102:14075-14079. PNAS Cover Article:
  • Leal, W. S., A. M. Chen, Y. Ishida, V. P. Chiang, M. L. Erickson, T. I. Morgan, and J. M. Tsuruda. 2005. Kinetics and molecular properties of pheromone binding and release. Proc. Natl. Acad. Sci. USA 102:5386-5391.
  • Leal, W. S., P. H. G. Zarbin, H. Wojtasek, S. Kuwahara, M. Hasegawa, and Y. Ueda. 1997. Medicinal alkaloid as a sex pheromone. Nature 385: 213.
  • Leal, W. S. 1996 Chemical communication in scarab beetles: Reciprocal behavioral agonist-antagonist activities of chiral pheromones. Proc. Natl. Acad. Sci. USA 93: 12112-12115.