Whatâ€™s the News: Biochemists at the University of Arizona have found a promising new way to fight disease-carrying mosquitoes. In their research project, published in the journal PNAS, the scientists blocked mosquitoes’ ability to digest blood, making blood-sucking deadly to the winged pests. This technique could someday be used alongside other strategies to battle mosquitoes, like repellents and traps.
How the Heck:
- Mosquitoes, like many other insects, draw most of their nutrients from nectar. But when it comes time to produce eggs, female mosquitoes require large amounts of protein, which they get from blood. So, Roger Miesfeld and his research team decided to see what would happen if they blocked a mosquitoâ€™s ability to digest blood.
- The researchers focused on a protein complex called coatomer protein 1, or COPI, which is made up of several subunits that cells use to secrete gut enzymes that break down blood proteins. When a mosquito draws blood, cells lining its gut package enzymes in small droplets called vesicles, and release the packages into the gut.
- Using a technique called RNAi, the researchers shutdown individual COPI subunits in about 5,000 mosquitoes. Surprisingly, more than 90 percent of the yellow fever mosquitoes died within 48 hours of blood feeding. â€œWhen she does [feed], all hell starts breaking loose, biochemically and anatomically speaking,â€ Miesfeld said in a prepared statement.
- The researchers think that the removal of a COPI subunit makes the whole secretion process defectiveâ€”It causes the cells lining a mosquitoâ€™s gut to fall apart, allowing blood to seep into its body.
Whatâ€™s the Context:
- There are many techniques scientists have used to kill mosquitoes. Recently, a study in the American Journal of Tropical Medicine and Hygiene showed that a cheap deworming pill used against river blindness is temporarily effective for battling the spread of malaria, too. Mosquitoes that bite people who have taken the drug ultimately die.
- Researchers are also looking at ways to prevent mosquitoes from biting people. Earlier this year, scientists found a possible new mosquito repellent: a molecule that overloads a mosquitoâ€™s sense of smell.
- Other scientists want to use mosquitoesâ€™ sense of smell to draw them into traps. The lure? Smelly socks.
The Future Holds: Miesfeld says that the research could be used in conjunction with other mosquito-fighting techniques, if they can develop a small molecule that works in place of the injected RNAi. Scientists could douse mosquito nets with the molecule to create an effective mosquito-specific insecticide, or place it in a pill for people to swallow (as with the deworming pill above). Though, Miesfeld notes that genetic changes would eventually make mosquitoes immune to the molecule.
Reference: J. Isoe, J. Collins, H. Badgandi, W. A. Day, R. L. Miesfeld. PNAS Plus: Defects in coatomer protein I (COPI) transport cause blood feeding-induced mortality in Yellow Fever mosquitoes. Proceedings of the National Academy of Sciences, 2011; 108 (24): E211 DOI: 10.1073/pnas.1102637108
RedEaredSlider writes “Millions of people in the tropics suffer from malaria, a mosquito-borne disease that has been difficult to treat and which costs many developing countries millions of dollars per year in lost productivity. Up to now, efforts at controlling it have focused on attacking the parasites that cause it, keeping mosquitoes from biting, or killing the insects. But at Johns Hopkins University, Rhoel Dinglasan, an entomologist and biologist, decided to try another tack: immunizing mosquitoes. When a mosquito bites an infected human, it takes up some of the gametocytes. They aren’t dangerous to people at that stage. Since plasmodium is vulnerable there, that is the point Dinglasan chose to attack. A mosquito’s gut has certain receptor molecules in it that the plasmodium can bind to. Dinglasan asked what would happen if the parasite couldn’t ‘see’ them, which would happen if another molecule, some antigen, were binding to those receptors.”
Gisg writes “The University of Arizona team reported that their genetically modified mosquitoes are immune to the malaria-causing parasite, a single-cell organism called Plasmodium. Riehle and his colleagues tested their genetically-altered mosquitoes by feeding them malaria-infested blood. Not even one mosquito became infected with the malaria parasite”
wisebabo writes “Nathan Myhrvol demonstrated at TED a laser, built from parts scrounged from eBay, capable of shooting down not one but 50 to 100 mosquitos a second. The system is ‘so precise that it can specify the species, and even the gender, of the mosquito being targeted.’ Currently, for the sake of efficiency, it leaves the males alone because only females are bloodsuckers. Best of all the system could cost as little as $50. Maybe that’s too expensive for use in preventing malaria in Africa but I’d buy one in a second!” We ran a story about this last year. It looks like the company has added a bit more polish, and burning mosquito footage to their marketing.