Scientists discover exact receptor for DEET that repels mosquitoes

DEET has been the gold standard of insect repellents for more than six decades, and now researchers led by a University of California, Davis, scientist have discovered the exact odorant receptor that repels them.

fig. Biochemist Walter Leal has discovered which receptor on mosquito antennae detects DEET, making it an effective repellant.

They also have identified a plant defensive compound that might mimic DEET, a discovery that could pave the way for better and more affordable insect repellents. Findings from the study appear in the journal Proceedings of the National Academy of Sciences.

More than 200 million people worldwide use DEET, developed by scientists at the U.S. Department of Agriculture and patented by the U.S. Army in 1946.

A gut bacterium that attacks dengue and malaria pathogens and their mosquito vectors

Just like those of humans, insect guts are full of microbes, and the microbiota can influence the insect's ability to transmit diseases. A study published on October 23rd in PLOS Pathogens reports that a bacterium isolated from the gut of an Aedes mosquito can reduce infection of mosquitoes by malaria parasites and dengue virus. The bacterium can also directly inhibit these pathogens in the test tube, and shorten the life span of the mosquitoes that transmit both diseases.

George Dimopoulos and colleagues from Johns Hopkins University, USA, had previously isolated Csp_P, a member of the family of chromobacteria, from the gut of Aedes aegypti mosquitoes (which transmit dengue fever) in Panama. In the present study, they examined its actions on both mosquitoes and pathogens, and the results suggest that Csp_P might help to fight malaria and dengue fever at different levels.

Genetic tweak gave yellow fever mosquitoes a nose for human odor

One of the world's deadliest mosquitoes sustains its taste for human blood thanks in part to a genetic tweak that makes it more sensitive to human odor, according to new research.

 

 image : Researchers report that the yellow fever mosquito sustains its taste for human blood thanks in part to a genetic tweak that makes it more sensitive to human odor. The human-preferring 'domestic' form of the mosquito (right) contains a version of the odor-detecting gene AaegOr4 in its antennae that is highly attuned to sulcatone, a compound prevalent in human odor. The researchers found that this gene is more abundant and more sensitive in the domestic form than in its ancestral 'forest' form (left), which prefers the blood of non-human animals. Credit: Carolyn McBride, Department of Ecology and Evolutionary Biology and the Princeton Neuroscience Institute

Researchers report in the journal Nature that the yellow fever mosquito contains a version of an odor-detecting gene in its antennae that is highly attuned to sulcatone, a compound prevalent in human odor. The researchers found that the gene, AaegOr4, is more abundant and more sensitive in the human-preferring "domestic" form of the yellow fever mosquito than in its ancestral "forest" form that prefers the blood of non-human animals.

The research provides a rare glimpse at the genetic changes that cause behaviors to evolve, explained first author Carolyn "Lindy" McBride, an assistant professor in Princeton University's Department of Ecology and Evolutionary Biology and the Princeton Neuroscience Institute who conducted the work as a postdoctoral researcher at the Rockefeller University. Uncovering the genetic basis of changes in behavior can help us understand the neural pathways that carry out that behavior, McBride said.