Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Proteins show promise for mosquito control


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:

More articles from Life Sciences:

nachricht Novel mechanisms of action discovered for the skin cancer medication Imiquimod
21.10.2016 | Technische Universität München

nachricht Second research flight into zero gravity
21.10.2016 | Universität Zürich

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>