Fig. 6: Transmission electron micrographs showing ultrastructure of P. falciparum ring stages and post DHA treatment on Day 1 and 5.

a Low-power transmission electron micrograph of ring stages with distinct organelles such as nucleus (N), ribosomes, plastid and rough endoplasmic reticulum (RER). b Low-power transmission electron micrograph of dormant parasites 1 day post DHA treatment, showing the transformation of parasites to round and compact forms, with the nucleus (N) being the most identifiable organelle in the parasite. Note the presence of electron dense spots in the RBC cytosol (blue arrowhead). c Low-power transmission electron micrograph of d5MDPs showing a completely different morphology characterized by lack of intracellular organellar structure except for the nucleus (N) and the presence of large “vacuole-like” structures (VS) and multi-membrane structures (MAS). An increase in electron dense spots (blue arrowhead) was also observed. d Low-power transmission electron micrographs with increasing magnification (orange boxes) showing electron dense spots at Day 5 post DHA treatment were observed in the cytosol of 48 out of 65 infected RBCs (73%) on Day 5 (Fig. S13). Additionally, clusters of these spots surrounded by membranous structures, forming packets, were observed in d5MDP infected-RBCs. All represented TEM pictures are from two independent experiments. Approximately 100 images were generated per each day captured.