From ABC Science, 5 June 2015:
A highly resistant malaria parasite hijacks resources in immature red blood cells to defend itself against the impact of anti-malarial drugs, researchers have found.
The study, by Australian and Scottish researchers, looks at how different species of malaria parasite behave inside the human body.
Their findings, published today in PLOS Pathogens, also sheds light on why resistance to anti-malaria drugs is more common in some species of the parasite than others.
Of the two species of malaria parasites that most commonly affect humans, one — Plasmodium falciparum — grows mostly inside mature red blood cells, while the other — Plasmodium vivax — prefers the environment of immature red blood cells, known as reticulocytes.
“This has always been interesting because they have quite different biologies so it raises the question as to whether drugs for one species would be as effective against others,” says co-author Professor Malcolm McConville, professor of biochemistry at the University of Melbourne.
Researchers used a novel approach known as metabolomics, which involves a detailed analysis of the biochemical processes inside a cell or organism.
This enabled them to look at the different environments inside the two types of red blood cells.
“We found that reticulocytes, because they’re on the way to developing into mature red blood cells, have much more complex metabolism than mature red blood cells,” says McConville, also head of Metabolomics Australia.
“The maturation of red blood cells involves losing all the structures that are found in the reticulocytes; basically they’re bags of haemoglobin in the end so they don’t need all the other things normal cells have,” he says.
This more complex metabolic environment in the reticulocytes provides the ideal haven for P. vivax; giving it access to metabolites that it can use as a sort of crutch to support its own systems if they’re knocked out by anti-malarial drugs. Read more.