Whenever an infected mosquito bites someone, it can also leave a deadly cargo in its victim’s bloodstream: parasites that can cause malaria, a disease almost a million people die from every year. Research scientists from Bayer are now working on an entirely new strategy to fight the tropical fever: they are looking for compounds that block specific odor receptors in mosquitoes. Since the insects rely on their sense of smell to find their way around, this would stop them finding victims to bite – thus dramatically reducing the spread of malaria.
In order to find substances that block mosquitoes’ ability to smell, scientists use Bayer CropScience’s vast substance library. This facility contains over two million chemical compounds that could potentially make insects “blind” to odors. Since testing every single substance on live mosquitoes would be an expensive and extremely long process, they carry out biochemical screening in the laboratory. Bayer’s research scientists use special scent-detecting cells for this purpose. These cells were produced in a research cooperation with the leading scientists in this area, Prof. Leslie Vosshall (Rockefeller University) and Prof. Richard Axel (Columbia University), using gene transfer to insert the relevant sections of genetic material into the cells, which then produce odor-sensitive protein structures. “These cells have a sense of smell which is almost as acute as that of insects,” says Dr. Katharina Wölfel, head of the project at Bayer CropScience.
The promising substances picked out through the screening are then examined more closely and eventually tested on living insects. If their odor receptors are blocked, humans are practically invisible to mosquitoes, and consequently protected against malarial infection. But the “molecular clothes-peg” for scent receptors has other benefits, too: the mosquitoes cannot find a mate, or get back to their breeding grounds. Depriving these deadly pests of their sense of smell also makes it harder for them to find food. This significantly weakens the population.
The project, which is funded via the “Grand Challenges in Global Health” initiative with resources from the U.S. Foundation for the National Institutes of Health, also offers potential for agriculture. Researchers are looking not only for substances that act against mosquitoes but can also lead astray greedy crop pests. This could lead to very environmentally friendly insecticides for use in crop protection. And because insects’ sense of smell works in a completely different way from that of humans, the compounds would be completely safe for people. Innovative solutions might also be found for animal parasites like ticks that can likewise transmit dangerous diseases. If Bayer’s research scientists succeed with their insect-puzzling strategy, this could in future make people, homes or entire fields of grain invisible to insect pests – thereby also securing harvests.
For additional information and more stories see research, the Bayer scientific magazine: http://www.research.bayer.com/en/homepage.aspx
