Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Proteins show promise for mosquito control

13.09.2004


Mosquito abatement usually means one thing: blasting the pesky critters with pesticides. Those pesticides, although highly effective, can impair other organisms in the environment.



Que Lan, insect physiologist at the University of Wisconsin-Madison, and her colleagues in the entomology department are working on a new, more targeted approach to mosquito control: inhibiting their ability to metabolize cholesterol.

Cholesterol, the sticky substance that accumulates on the lining of human arteries, is an important component of cell membranes in vertebrates and invertebrates. In mosquitoes, it is vital for growth, development and egg production.


Unlike humans, mosquitoes cannot synthesize cholesterol. They must obtain it from decomposed plants they eat while in their larval stage, living in shallow waters. Plants make phytosterol, which is converted to cholesterol in the mosquito’s gut.

Using the yellow fever mosquito, Aedes aegypti, Lan and her research colleagues discovered that a sterol-carrying protein, AeSCP-2, is the vehicle that transports cholesterol in mosquito cells. Cholesterol is hydrophobic. In order to transport it in a liquid medium, such as blood or cell fluids, organisms must have a way to shield it from the watery environment through which it moves. That shield is typically a carrier protein, such as SCP-2.

Lan and her colleagues reasoned that if they could block the carrier protein, it would disrupt the uptake of cholesterol by the mosquito. Screening what she calls "a small chemical library of 16,000 compounds," Lan and her team found 57 compounds that inhibited the cholesterol-binding capacity of SCP-2.

The top five most viable inhibitor compounds were then tested on mosquito larvae, producing promising results--the larvae died. The results were dose-dependent; that is, at higher concentrations, larger numbers of larvae died. Still, the concentrations were very small, Lan says, in the range of 10 parts per million.

Lan has a somewhat personal vendetta against disease-carrying mosquitoes. Growing up in China, she contracted malaria when she was 13. A school teacher recognized her symptoms and encouraged her to see a physician. "I was drenched in sweat and pale as paper," Lan recalls. Interestingly, her father had malaria when he was a teenager. "That’s 50 percent of my family," she says.

"Control is urgent," Lan says. "Mosquito-borne illnesses are endemic in parts of China. Malaria is a big problem in south-central China. South of the Yangtze River the infant mortality rate is high, especially in homes without screens on the windows."

Although Lan grew up in Wuhan, a bustling city of 7 million, there were rice fields nearby. "It is a land of 10,000 lakes," she says, where rice is a major crop and the weather is hot and humid, perfect for mosquito breeding.

Worldwide, mosquitoes are notorious for spreading not only malaria, but also dengue fever (so painful it’s commonly called "break bone fever"), several forms of encephalitis, yellow fever, and West Nile virus. And the numbers are increasing. The World Health Organization estimates that there are 300 million cases of mosquito-borne diseases annually. Malaria is the biggest killer, claiming a million lives a year.

The two main approaches to future mosquito control, as Lan sees it, are genetic and chemical. In the genetic approach, she says, researchers are working on ways to modify the malaria mosquito so that it cannot transmit disease, but it can still take a blood meal. The problem with that approach, she says, is that there are many uncertainties about releasing genetically modified organisms into the environment.

Lan believes that a more fine-tuned chemical approach is more practical: only one compound is selected, it works for a short period, and it targets a single insect. "People might ask, ’Why do we need more pesticides?’" Lan says. The answer is twofold: resistance and the effect on non-target species. "I believe you should develop smart pesticides to only kill the mosquitoes," Lan says. "We don’t want to go down the same road as DDT."

To that end, her team is testing the most promising handful of SCP inhibitor compounds on a variety of insect and vertebrate species. So far three of the five compounds tested were not toxic to mouse cells and the other two were only slightly toxic. They will also test the compounds on other pest species, including flies, roaches and termites.

Environmental and degradation tests have yet to be performed. "We want a specific target with low residue time- two to three weeks and it should be degraded," Lan says.

Lan and her team have patented the gene and the methods for screening the compounds. It will take a year to screen another 20,000 chemicals. After that, they will be looking for companies to develop the compounds into chemical inhibitors for widespread mosquito control.

"Four years ago (when Lan joined the faculty of UW-Madison) I couldn’t imagine having five viable compounds in hand," Lan says. "This is the first example of looking at target proteins for pest management. No one has done this with insects."

Que Lan | EurekAlert!
Further information:
http://www.entomology.wisc.edu

More articles from Life Sciences:

nachricht Nesting aids make agricultural fields attractive for bees
20.07.2017 | Julius-Maximilians-Universität Würzburg

nachricht The Kitchen Sponge – Breeding Ground for Germs
20.07.2017 | Hochschule Furtwangen

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

Im Focus: On the way to a biological alternative

A bacterial enzyme enables reactions that open up alternatives to key industrial chemical processes

The research team of Prof. Dr. Oliver Einsle at the University of Freiburg's Institute of Biochemistry has long been exploring the functioning of nitrogenase....

Im Focus: The 1 trillion tonne iceberg

Larsen C Ice Shelf rift finally breaks through

A one trillion tonne iceberg - one of the biggest ever recorded -- has calved away from the Larsen C Ice Shelf in Antarctica, after a rift in the ice,...

Im Focus: Laser-cooled ions contribute to better understanding of friction

Physics supports biology: Researchers from PTB have developed a model system to investigate friction phenomena with atomic precision

Friction: what you want from car brakes, otherwise rather a nuisance. In any case, it is useful to know as precisely as possible how friction phenomena arise –...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

The technology with a feel for feelings

12.07.2017 | Event News

Leipzig HTP-Forum discusses "hydrothermal processes" as a key technology for a biobased economy

12.07.2017 | Event News

 
Latest News

Researchers create new technique for manipulating polarization of terahertz radiation

20.07.2017 | Information Technology

High-tech sensing illuminates concrete stress testing

20.07.2017 | Materials Sciences

First direct observation and measurement of ultra-fast moving vortices in superconductors

20.07.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>