Walter Soares Leal (born February 2, 1954) is a Brazilian biochemist and entomologist who is known for identifying pheromones and mosquito attractants, and elucidating a mechanism of action of the insect repellent DEET. Leal was the first non-Japanese to earn tenure at the Ministry of Agriculture, Forestry, and Fisheries of Japan. In 2000, he accepted a position as associate professor at the University of California, Davis. Leal is a Distinguished Professor in the Department of Molecular and Cellular Biology. He served as chair of the entomology department at UC Davis (now Department of Entomology & Nematology). Education and early life Leal attended the Federal University of Pernambuco, from which he graduated in 1982 with a B.Eng degree in chemical engineering. In 1987, he got his MS in agricultural chemistry from Mie University in Tsu-Mie, Japan. While still residing in Japan, Leal attended the University of Tsukuba, division of Applied Biochemistry, graduating with a Ph.D. three years later. While in high school, Leal worked as a sports reporter to pay tuition and fees and later as a high school teacher – a career he started while a freshman in college, under the supervision of his favorite teacher, Aloísio Guimarães Sotero. Research Leal has identified complex pheromones from many insect species, including scarab beetles, true bugs, long-horned beetles, and moths. Intrigued by chiral discrimination by scarab beetles, he became interested in the molecular basis of insect olfaction. His laboratory discovered a pH-dependent conformational change in pheromone-binding proteins (PBPs) from moths before their 3D structures were known. In collaboration with Jon Clardy and Nobel Laureate Kurt Wuthrich, they determine the first 3D structures of PBPs. Subsequently, his laboratory studied the kinetics of pheromone binding and release by PBPs. Leal laboratory fully identified the first odorant-degrading enzymes from moths and scarab beetles. In 2005, Leal coined the term “reverse chemical ecology” for employing olfactory proteins to identify semiochemicals of potential practical applications. Using this approach, he identified oviposition attractants for mosquitoes. His laboratory identified olfactory receptor neurons (ORNs) highly sensitive to nonanal, which might play a crucial role in Culex mosquitoes shifting from birds to humans, implicated in West Nile virus transmission. Leal and his collaborators identified mosquito ORNs sensitive to DEET and subsequently identified an odorant receptor, CquiOR136, sensitive to DEET and other commercially available insect repellents. Leal and collaborators discovered a receptor, CquiOR32, with dual inhibitory/excitatory properties manifested in the Xenopus oocyte