Recent scientific studies have shown that fatty acids emitted by the skin can create an intense scent that mosquitoes cannot resist.
It is impossible to hide from a female mosquito. Female mosquitoes hunt down every member of humanity by tracking their carbon dioxide emissions, body temperature and body odor. But some of us are definite “mosquito magnets” who get a fair number of bites. There are many popular theories as to why this happens. But there are few reliable data to support most of these theories, said Leslie Vosshall, director of the Institute for Neurogenetics and Behavior at Rockefeller University. I’m here.
That’s why Vosshall and Maria Elena De Obaldia, a former postdoc in her lab, set out to investigate the major theories that explain the attraction of different mosquitoes.Through research, they recently demonstrated that fatty acids emanating from the skin can create a powerful scent that mosquitoes cannot resist. cell October 18th.
“The high levels of these fatty acids in the skin and its susceptibility to mosquito attraction,” said Vosshall, a Robin Kemmers Neustein professor at the Rockefeller University and chief scientific officer at the Howard Hughes Medical Institute. There is a very strong connection between them.
A female Aedes aegypti bites a Rockefeller University researcher.Credit: Alex Wild
A tournament that no one wants to win
In a three-year study, eight participants were asked to wear nylon stockings on their forearms for six hours a day. This process was repeated for several days. Over the next few years, researchers tested nylons against each other in all possible combinations through round-robin format “tournaments.” They used his binary olfactometer assay built by De Obaldia. The assay consisted of a plexiglass chamber divided into two tubes, each terminated by a box holding a stocking.they put Aedes aegypti Mosquitoes, the main vector species for Zika, dengue, yellow fever and chikungunya, were observed in the main chamber as insects flew down the tube towards the nylon or other nylons.
overwhelmingly attractive target Aedes aegypti Subject 33 was four times more attractive to mosquitoes than the next most attractive study participant, and a staggering 100 times more attractive than the least attractive subject, 19.
Because the trial samples were anonymized, the experimenters did not know which participants wore which nylons. will notice. This is because the insects will swarm towards the sample. “It’s obvious within seconds of starting the assay,” he says. “This is the type of thing that really excites me as a scientist. This is the real deal. It’s not splitting the hair. This is a huge effect.”
Participants were classified as high and low attractors, and the scientists set out to determine what differentiated them. They identified 50 molecular compounds that elevated the skin’s moisturizing barrier. The substance is found in sebum and is used by skin bacteria to produce our unique body odor.
To confirm their findings, Vosshall’s team enrolled 56 more people in a validation study. Again, subject 33 was the most attractive and the attraction lasted longer.
“Some of the subjects have been in the study for several years, and we’ve found that if they’re mosquito magnets, they’re still mosquito magnets,” says De Obaldia. A lot could have changed about his behavior, but this was a very stable trait of that person.”
Even knockouts find us
Humans primarily produce two classes of odors that mosquitoes detect with two different sets of odorant receptors: Orco receptors and IR receptors. To see if they could manipulate mosquitoes that can’t identify humans, the researchers created mutants that lacked one or both of the receptors. Orco mutants remained attracted to humans and were able to distinguish between mosquito magnets and low attractants, whereas IR mutants lost their attractiveness to humans to varying degrees, but still made us I had the ability to find
These were not the results the scientists had hoped for. “The goal was a mosquito that loses all attraction to people, or a mosquito that loses all attraction to everyone and cannot distinguish between subject 19 and subject 33. It’s crazy,” says Vosshall. Development of more effective mosquito repellents. “But it wasn’t what we saw. We were disappointed.”
These results are Vosshal’s recent researchis also posted on cellwhich revealed the redundancy of Aedes aegypti A highly complex olfactory system. It’s a fail-safe that female mosquitoes rely on to live and reproduce. Without blood, neither can she. That’s why “she has a backup plan and a backup plan and a backup plan to match the different skin chemistries of the people she chases,” Vosshall says.
Mosquito scent trackers are apparently indestructible, so it’s hard to imagine a future where we’re no longer the number one meal on our menu. is to Smearing sebum and skin bacteria from the skin of a less attractive person, such as subject 19, onto the skin of a highly attractive person, such as subject 33, may provide a mosquito masking effect.
“We haven’t done that kind of experiment,” says Vosshall. “It’s a tough experiment. But if it works, by doing dietary and microbiome interventions that put bacteria on the skin that can somehow alter how they interact with sebum, people like Subject 33 will 19. But that’s all very much speculation.
She and her colleagues hope the paper will inspire researchers to test other mosquito species, including the genus Anopheles mosquitoSpreading Malaria .Vosshall adds:
Reference: “Differences in mosquito attraction to humans are related to skin-derived carboxylic acids”[{” attribute=””>acid levels” by Maria Elena De Obaldia, Takeshi Morita, Laura C. Dedmon, Daniel J. Boehmler, Caroline S. Jiang, Emely V. Zeledon, Justin R. Cross and Leslie B. Vosshall, 18 October 2022, Cell.
DOI: 10.1016/j.cell.2022.09.034
