Fig. 3. Fluorescence intensity measurements from uninfected and parasitized erythrocytes. (A) Representation example of fluorescence symmetry through a z-stack series of a horizontally oriented, healthy AA erythrocyte. Although the z-stack consisted of 70 frames, only those frames containing the erythrocyte are shown. Each fluorescence intensity profile was centered along the vertical axis for representational purposes. Owing to the high photostability of quantum dots, no measurable reduction in fluorescence intensity occurred throughout the z-stack sequence. (B) Cell-by-cell comparison of mean total fluorescence intensity occurring during the development of malaria parasites in AA and CC erythrocytes. The total fluorescence was measured using 3D-reconstructed, sum projection images. Data were normalized against uninfected erythrocytes (U) for each genotype. Error bars represent the standard error of the mean (s.e.m.). n=3-11 (see Table 1).