Sequenced Malaria genome exposes novel drug targets

The malaria parasite genome has been sequenced and is already revealing novel drug targets that could lead to effective treatment of the disease.

Professor Geoff McFadden and his team from the University of Melbourne recently discovered that the malaria parasite evolved from a plant-like organism that survived by photosynthesis. It is this plant-like part that, so far, appears to be a depot for anti-malarial drug targets. Consequently, existing safe herbicides are providing leads for some of these new drugs. So too are antibiotics.

"Our role in this international collaboration is to find the genes associated with the relict plant component of the parasite. This has been a key success of the study. At least 12 new drug targets have been identified so far from the plant-like genes," says Prof. McFadden.

Human malaria is caused by infection with parasites of the Plasmodium species that are transmitted by Anopheles mosquitoes. Plasmodium species are members of large group numbering over 5000 species that harbour a relict chloroplast, the part of a plant that carries out photosynthesis. Scientists have determined this relict, called the apicoplast, is essential for the malaria parasite's survival, but its exact role is unclear.

McFadden's team has gone someway to unraveling the apicoplast's mysteries. They have revealed that it is the apicoplast that houses the herbicide-sensitive pathways and compounds with potential for drug therapy. Stuart Ralph, a PhD student in McFadden's lab, has helped identify three metabolic pathways in the apicoplast that are distinct from metabolic pathways in humans or the mosquito.

Chloroplasts themselves evolved from bacteria, opening the door to another common drug treatment, antibiotics. Doxycycline is a common and effective anti-malarial in use today and it is an antibiotic.

Approximately 40% of the world's population lives in areas where malaria is transmitted. There are an estimated 300-500 million cases and at least 1 million deaths from malaria each year. Recent studies suggest that the number of malaria cases may double in 20 years if new methods of control are not devised and implemented.

Item provided courtesy of The University of Melbourne