Nayeli Lomeli/Staff Writer
Just like we savor chocolate chip cookies at the smell of their warm aroma, mosquitoes do the same for their blood meal at the smell of human odor and scientists have discovered how.
Matthew DeGennaro, a biologist and leader of FIU’s Laboratory of Tropical Genetics, and his team of researchers recently identified an olfactory receptor in “Aedes aegypti” mosquitoes that affects their behavior when finding a host to feed from. It is the Ionotropic Receptor 8a, or IR8a, found in the mosquito’s attanae which helps these insects find humans.
They determined that this pathway senses the acidic volatiles that are found in human odor, including lactic acid which is produced when we sweat.
“This may be an odor which defines us as being human… [and] the loss of IR8a cannot be compensated for by other olfactory receptor pathways,” said DeGennaro.
The work began in 2013 when DeGennaro was a postdoctoral researcher at the Rockefeller University. He created the first mutant mosquito and removed another olfactory receptor known as Orco. Before the mutation it was believed that this gene controlled all of olfaction in the mosquito, however, he learned that mosquitoes were still attracted to humans.
“The orco mutants did not lose their ability to seek hosts in the presence of carbon dioxide and I wanted to find what else was involved,’ said DeGennaro.
DeGennaro hopes to continue understanding whether this family of receptors is really important in the choice mosquitoes make between humans and animals, as well as if it influences nectar seeking, which mosquitoes also do. In addition, his team wants to understand which chemicals and odors are binding to which receptors in the pathway. They are working on this in collaboration with Peter Larsson at the University of Miami Medical Center.
“It is important for us to fundamentally understand how mosquitoes find us, because it is by finding us that they can spread disease,” said DeGennaro.
Although this is only a step in understanding how they find us and more experiments are needed, DeGennaro says that this can be an important pathway for a repellent design that can help block the sensation of acidic volatiles in mosquitoes. This information can also be used as a molecular target to design new chemicals that are more attractive than human odor that could pull mosquitoes into traps and keep them away from us.
John S. Castillo, third author in this research and Ph.D. student in the DeGennaro lab, feels honored to be part of this team.
“I think it’s important to show our achievement to [everyone], it’s more important for me to share our knowledge,” said Castillo.
This is the first major publication for DeGennaro’s lab at FIU and he would like to thank his international collaborators who are also authors in the paper. As the first person in his family to earn his Ph. D., he feels honored to be at FIU because he says the research community here has helped him reach the goals of his research program.
He added that the initial stages of this work were done by FIU undergraduates and that he thinks FIU students can achieve anything.
“I know that sometimes when you grow up in an environment where people don’t believe in you, you think that you can’t, but you should never stop believing and should try to make your dreams a reality,” said DeGennaro.
DeGennaro has received coverage from NPR, The L.A. Times, The New York Times, Le Monde and La República among other major publications and said that it is great that people are interested in this kind of research because it affects many people in the tropics and subtropics areas.
“My laboratory is all about using genetics to help people in the tropic and subtropics,” said Dr. DeGennaro.
The research was published in Current Biology. Featured photo taken from WikiCommons.
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