Figure 4

Localization using confocal microscopy. Bright field, fluorescence, and overlay DIC images of uninfected and infected cells loaded with Fluo-8 AM (top and bottom pairs of rows, respectively). Cells were loaded in the presence or absence of probenecid (Pr) and imaged in media containing 1 mM Ca⁺⁺. Cell-associated fluorescence is not detected in uninfected cells in the absence of probenecid, consistent with exported Fluo-8; probenecid reveals a weak intracellular signal. With infected cells, a clear signal is detected within both host and parasite compartments. Cell-to-cell variability prevented quantitative assessment of probenecid effect.