Table 2.
Comparison of Fura-Red derived resting [Ca2+] in the different compartments of erythrocyte cytosol (RBCcyt, iRBCcyt), parasite cytoplasm (Parcyt), and digestive vacuole (Parvac) with the apparent Fluo-4 derived Ca2+ concentrations using the in situ calibration results and resting Fluo-4 fluorescence intensities from hundreds of intact infected and non-infected erythrocytes. The non-ratiometric dye Fluo-4 suggests an inaccurately elevated [Ca2+] in the parasitic compartments of Dd2, as the concentration of dye was incorrectly assumed to be evenly distributed. In contrast, the ratiometric dye Fura-Red indicates no major Ca2+ storage properties of the digestive vacuole
| Compartment | Fura-Red [Ca2+]resting (μM) [12] | Fluo-4 Kd (μM) | Apparent Fluo-4 [Ca2+]resting (μM) |
|---|---|---|---|
| RBC | |||
| RBCcyt | 0.16 | 9.10 | 1.40 |
| HB3 | |||
| iRBCcyt | 0.08 | 41.00 | 2.30 |
| Parcyt | 0.40 | 10.00 | 3.10 |
| Parvac | 0.45 | 2.20 | 1.00 |
| Dd2 | |||
| iRBCcyt | 0.08 | 41.00 | 3.50 |
| Parcyt | 0.35 | 8.50 | 17.80 |
| Parvac | 0.45 | 5.20 | 39.00 |