Bacteria Stops Malaria Parasites In Mosquito Gut

By genetically engineering a bacteria that lives in the digestive system of mosquitoes, scientists in China have devised a new strategy to control the spread of malaria.

AsianScientist (Oct. 25, 2017) – Using a bacteria strain that colonizes the mosquito digestive tract and spreads rapidly throughout the populations, scientists have successfully inhibited malaria transmission. They report their findings in Science.

Malaria, one of the most devastating infectious diseases worldwide, is caused by Plasmodium parasites that are transmitted through the bite of infected female anopheline mosquitoes.

Instead of using pesticides to kill the mosquitoes, paratransgenesis involves using genetically modified symbiotic bacteria to deliver anti-Plasmodium effector molecules to mosquitoes. However, strategies to spread such bacteria throughout mosquito populations require optimization.

In this study, a joint research team led by Professor Wang Sibao at Shanghai Institute of Plant Physiology and Ecology of the Chinese Academy of Sciences, and Professor Marcelo Jacobs-Lorena at Johns Hopkins University, has developed a promising way to stop mosquitoes from spreading malaria.

The researchers identified a bacterial strain (AS1) of the genus Serratia isolated from Anopheles mosquito ovaries. Serratia AS1 fed to adult mosquitoes stably colonized the mosquito midgut, crossed the midgut epithelium and colonized the reproductive organs.

Importantly, the AS1 bacteria were transmitted from males to females via mating. Moreover, Serratia AS1 was vertically transmitted from female to larval progeny via attachment to laid eggs, primarily on the chorion ridges and floats. These bacteria propagated in the water and were ingested by the larvae that hatch from these eggs.

The researchers demonstrated that this bacterium can spread rapidly throughout mosquito populations and persist for multiple subsequent generations. Moreover, Serratia AS1 could be genetically manipulated to secrete anti-Plasmodium effector molecules by use of the Serratia HasA (heme-binding protein) exporting system.

The recombinant strains strongly inhibited development of the human malaria parasite Plasmodium falciparum in mosquitoes, but do not have an obvious negative impact on mosquito longevity or fecundity and fertility.

Therefore, Serratia AS1 makes it possible to develop a powerful tool against Plasmodium infection of mosquitoes in the field, the researchers concluded.

The article can be found at: Wang et al. (2017) Driving Mosquito Refractoriness to Plasmodium falciparum with Engineered Symbiotic Bacteria.


Source: Chinese Academy of Sciences.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.

Asian Scientist Magazine is an award-winning science and technology magazine that highlights R&D news stories from Asia to a global audience. The magazine is published by Singapore-headquartered Wildtype Media Group.

Related Stories from Asian Scientist