Mosquito-borne diseases cause approximately 700,000 deaths each year. Using insect repellents can save lives, including the chrysanthemum extract called pyrethrum that has been used by humans for thousands of years.A new study exist Nature Communications Finally, the working principle of pyrethrum is shown, and the two ingredients work together to deter nasty vampires.
The senior author of the study, Duke University neurotoxicologist Ke Dong pointed out that over time, mosquitoes tend to become resistant to certain insect repellents. Therefore, “new alternatives need to be continuously developed to eventually replace the existing ones,” she said. It may be helpful to understand the deworming mechanism. “We are very excited because we are finally beginning to understand how a popular natural insect repellent, used globally, prevents mosquitoes from biting people.”
To observe the effects of pyrethrum, Dong and her colleagues attached tiny electrodes to the hair of the mosquito’s antennae. This allowed them to measure insect responses to insect repellents at the level of individual odor receptors in nerve cells. Many disease-carrying mosquito species have more than 100 such receptors, but researchers have found that pyrethrum activates a receptor specifically called Or31-they confirmed that if mosquitoes are genetically modified and lack this receptor, they Will not shrink from this substance.
Dong said that unlike many other odor receptors, Or31 happens to appear in all known disease-carrying mosquito species. In addition, many other natural insect repellents (unlike pyrethrum) work by activating multiple odorant receptors, and researchers know little about how these other receptors work. Taking these factors into consideration, scientists suggest that Or31 can be used as a clear and universal target for the development of better insect repellents.
The team also used chemical analysis to determine how the two molecular components of pyrethrum-EBF and pyrethrin-trigger an insect repellent response. Mosquito experiments show that these chemicals work best when combined: EBF activates Or31, and pyrethrins enhance the insect repellency by enhancing nerve signals.
Dong and her colleagues next plan to study the neural circuits behind rejection caused by pyrethrum and similar natural substances. They will continue to test other potential insect repellent molecules, including the main ingredient in citronella oil, and they found that it can also activate Or31.
Johns Hopkins University neuroscientist Christopher Porter specializes in insect olfactory but did not participate in this research. He said these findings may eventually help create “super insect repellent.” Porter said that in particular, figuring out which neurons determine how mosquitoes respond to certain odors can reveal new ways to manipulate their behavior. “Maybe one day,” he observed, “we can determine how to further increase this dial, or how to induce mosquitoes to be repelled by other odors-such as those that would normally attract them to humans.”