Dealing with change: the different microenvironments faced by the malarial parasite

In a new paper, Pillai et al. (2013) report that in vitro asexual blood-stage Plasmodium falciparum parasite cultures are able to grow unhindered in media with surprisingly broad ranges of ionic constituents. In doing so, the authors demonstrate that long known changes in the cationic composition of the cytosol of host erythrocytes induced by developing intra-erythrocytic parasites are not essential for growth. Moreover, their results also suggest that besides a low K(+) environment, which has been shown to trigger key processes such as microneme secretion and merozoite egress, there must be alternative signals that can regulate these processes and allow normal growth in diverse ionic environments. Given these findings, mechanisms by which the parasite is able to sense and tolerate different ionic environments are worthy of further study in an effort to identify urgently needed novel anti-malarial strategies.