Fig. 5.

NanoLuc imaging of P. berghei detached cells allows calculation of merozoite numbers. a Schematic representation of a detached cell. The calculation of merozoite numbers within a detached cell is derived from measurement of the detached cell volume. b Representative bioluminescent image of 64 individual detached cells. c Fluorescence images of 2 types of detached cell accounting for variability in luminescent measurements. The top panel shows a merosome (M) with even distribution of merozoites within the cell body. The bottom panel shows a large detached cell (L-DC) with even distribution of merozoites within the cell body. Scale bar corresponds to 10 μm. d Scatter plot showing significant correlation of detached cell volumes and merozoite numbers (y-axis), with and PbNLuc luminescence (x-axis). 100 individual detached cells symbolizing successful completion of PbNLuc liver infections (represented by each dot) were detected by mCherry-based fluorescence microscopy, imaged, and then individually captured and lysed for luminescence imaging. The radius of the detached cell was measured, and the volume of the detached cell thereby estimated as described in (a) [luminescence measured in photons per second (p/s)]