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Study provides better understanding of how mosquitoes find a host

Date:
March 10, 2010
Source:
USDA/Agricultural Research Service
Summary:
The potentially deadly yellow-fever-transmitting Aedes aegypti mosquito detects the specific chemical structure of a compound called octenol as one way to find a mammalian host for a blood meal.
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FULL STORY

Mosquitoes can detect a very fine chemical structure difference in octenol, a compound emitted by mammals, according to new research by ARS scientists.
Credit: Photo by ARS Photo Unit

The potentially deadly yellow-fever-transmitting Aedes aegypti mosquito detects the specific chemical structure of a compound called octenol as one way to find a mammalian host for a blood meal, Agricultural Research Service (ARS) scientists report.

Scientists have long known that mosquitoes can detect octenol, but this most recent finding by ARS entomologists Joseph Dickens and Jonathan Bohbot explains in greater detail how Ae. aegypti -- and possibly other mosquito species -- accomplish this.

Dickens and Bohbot, at the ARS Invasive Insect Biocontrol and Behavior Laboratory in Beltsville, Md., have shown that Ae. aegypti taps into the "right-handed" and "left-handed" structural nature of octenol, which is emitted by people, cattle and other mammals. This ability to detect the "handedness" of molecules has been shown in mammals, but the discovery is the first case of scientists finding out how it works in an insect, according to the researchers.

When they hunt for a blood meal, mosquitoes hone in on a variety of chemicals, including carbon dioxide, lactic acid, ammonia and octenol. Octenol is one of many carbon-based compounds that have a molecular structure that can take on either a "right-handed" or "left-handed" form. Each form is a mirror image of the other, and a form's "handedness" is determined by how its molecular bonds are assembled.

The scientists used frog eggs to help them make their discovery. They injected RNA from Ae. aegypti into the frog eggs, allowing the egg membranes to mimic the mosquito's ability to detect octenol. Then they attached microelectrodes to the frog egg cell membranes, passed octenol over them and recorded the electrical signals stimulated by the odors.

They ran the tests using both the right- and left-handed forms of octenol. The scientists found heightened electrical activity when the membrane was exposed to the right-handed form, and weakened activity when it was exposed to the left-handed form.

There are many natural compounds that can take on either a right-handed or left-handed form. While the effects of those differences on many plants and animals remains a mystery, the report, published in PLoS ONE, shows the effects of octenol's dual structure on the yellow fever mosquito and adds to scientists' understanding of how mosquitoes sense the world around them. It also may open the door to speedier development of better mosquito repellents and traps, according to Dickens.

The team's research is being funded by the Department of Defense Deployed War Fighter Protection Research Program.

ARS is the principal intramural scientific research agency of the U.S. Department of Agriculture.


Story Source:

The above story is based on materials provided by USDA/Agricultural Research Service. The original article was written by Dennis O'Brien. Note: Materials may be edited for content and length.


Journal Reference:

  1. Jonathan D. Bohbot, Joseph C. Dickens. Characterization of an Enantioselective Odorant Receptor in the Yellow Fever Mosquito Aedes aegypti. PLoS ONE, 2009; 4 (9): e7032 DOI: 10.1371/journal.pone.0007032

Cite This Page:

USDA/Agricultural Research Service. "Study provides better understanding of how mosquitoes find a host." ScienceDaily. ScienceDaily, 10 March 2010. <www.sciencedaily.com/releases/2010/03/100309111633.htm>.
USDA/Agricultural Research Service. (2010, March 10). Study provides better understanding of how mosquitoes find a host. ScienceDaily. Retrieved April 25, 2015 from www.sciencedaily.com/releases/2010/03/100309111633.htm
USDA/Agricultural Research Service. "Study provides better understanding of how mosquitoes find a host." ScienceDaily. www.sciencedaily.com/releases/2010/03/100309111633.htm (accessed April 25, 2015).

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