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A Dynamo, a Maverick and an Inspiration
The competition was fierce.
We're talking 800 postdoctoral scholars on the UC Davis campus, 12 finalists and two winners.
Chemical ecologist Zain Syed, who helped discover the mode of action for the insect repellent DEET in the Walter Leal lab, UC Davis Department of Entomology, emerged as one of the two winners.
The occasion: the sixth annual postdoctoral scholar research awards, sponsored by the UC Davis Postdoctoral Scholars’ Association and the Office of Graduate Studies.
Syed and fellow recipient Izumi Maezawa of the Department of Pathology and Laboratory Medicine, UC Davis Health System, each received a certificate and a $500 cash prize.
So, the next time you’re applying DEET to ward off mosquitoes, you can thank Leal and Syed for why mosquitoes won’t go near you. For the past 50 years, scientists assumed that DEET jams the senses of a mosquito or masks the smell of the host.
Not so. Mosquitoes can smell DEET and they avoid it because it smells bad to them. No jamming. No masking. Just a smell that's not in their comfort zone.
The chemical ecologists identified the olfactory receptor neuron in the antenna that detects the repellent. Their work led to one of the most popular research articles ever published in the Proceedings of the National Academy of Sciences (PNAS). The research paper has been loaded 9317 times from August 2008 through April 2009.
What this research means is we may see a whole new direction in the development of novel and promising insect repellents.
Syed, a native of
“Zain has an an encyclopedic knowledge of the literature and he designs well-thought experiments,” said Leal, also praising him as “a good mentor to students in the department, college and elsewhere on campus.”
“Zain is the type of postdoc that every principal investigator dreams about one day having in their own laboratory,” wrote professor Gabrielle Nevitt of Neurobiology, Physiology, and Behavior,
Entomology professor Penelope Gullan, who supported the nomination, said: "As a faculty member in the same department as Dr. Syed, I have watched his research progress and accomplishments over the past four years. His recent achievements have been truly outstanding in terms of significant research findings and publications in highly rated journals."
A dynamo, a maverick and an inspiration: mosquitoes beware!
Congratulations!
Blood-fed mosquito
The Secret's Out
We know it works, but how?
Just how does DEET work? Does it jam the senses of a mosquito? Does it mask the smell of the host?
You spray the chemical repellent on your arm and thankfully, those darn skeeters leave you alone. They need a blood meal to develop their eggs, so off they buzz to find another host, one that’s not so inhospitable.
But why do mosquitoes avoid DEET?
Well, they avoid it because it smells bad to them. Yes, they can smell it--that's why they avoid it.
The groundbreaking research, the work of UC Davis chemical ecologist Walter Leal and researcher
The research contradicts a Science article published in March by researchers at
The Leal-Syed research solidly establishes the real mode of action.
Noted entomologist James "Jim" Miller of
Said Miller: "For decades we were told that DEET warded off mosquito bites because it blocked insect response to lactic acid from the host -- the key stimulus for blood-feeding. Dr. Leal and co-workers escaped the key stimulus over-simplification to show that mosquito responses -- like our own -- result from a balancing of various positive and negative factors, all impinging on a tiny brain more capable than most people think of sophisticated decision-making.”
“This new work corrects long-standing erroneous dogma, and shows that recent work on DEET mode-of-action published in the flagship journal, Science, apparently was flat-out wrong,” Miller said. “One of the great attributes of science is that, over time, it is self-correcting."
Leal, past president of the International Society of Chemical Ecology and former chair of the UC Davis Department of Entomology, said previous findings of other scientists showed a “false positive” resulting from the experimental design.
Now that we know that skeeters can smell it, this will no doubt lead to better methods of insect control. Or, as
Those darn female mosquitoes, always in a “Let-us-prey” mood, have clearly met their match: the "why" behind "Let us spray."
(For more information and a video,access this page.)
Culex quinquefasciatus
Spraying DEET
