Some of the biochemical tricks the malaria parasite uses to become resistant have been unravelled thanks to a series of discoveries by Dr Rowena Martin and her colleagues at the Australian National University.
She is using those insights to give a new lease of life to chloroquine, the wonder drug against malaria first discovered in the 1950s.
For more than half a century chloroquine saved hundreds of millions of lives, but now chloroquine-resistant malaria strains have become common in developing countries.
Rowena is working to understand what happened. The single-celled malaria parasite enters our bodies when we are bitten by an infected mosquito.
It eventually invades and plunders our red blood cells, consuming the haemoglobin contained within.
The digestion of haemoglobin, which takes place in the parasite’s stomach compartment, releases the iron-containing, nonprotein component, haem.
Free haem is toxic to the parasite, which responds by converting it to a harmless crystal. Chloroquine works by blocking the formation of these crystals.
Ten years ago researchers discovered that just a few small changes in a protein PfCRT were enough to give the parasite resistance to chloroquine. But they did not know what the changes did.
Rowena developed a system to study PfCRT in frog eggs—allowing her to examine it in isolation and in detail.
“We found that it moves chloroquine out of the parasite’s stomach compartment so that the drug can’t accumulate at its site of action.” For her achievements to date, in 2010 Rowena won a $20,000 L’Oréal Australia For Women in Science Fellowship.
Photo: Rowena Martin, the Australian National University, Canberra/The University of Melbourne. Credit: L’oréal Australia/SDP media.
Research School of Biology, The Australian National University, Rowena Martin, Tel: +61 2 6125 8589, Rowena.Martin@anu.edu.au, www.scienceinpublic.com.au/loreal