Fig. 10

Comparison of oil and water immersion objectives for imaging expanded samples. A P. berghei infected mosquito midgut was prepared by U-ExM, stained with SYTOX (cyan, DNA) and NHS ester Alexa Fluor 405 (greyscale, protein density), and imaged by Airyscan Microscopy. a Image of an oocyst using a 63 × oil-immersion objective showing a single X–Y slice and Z-Y projection (3D image rotated 90° to the right). Using this imaging setup, the image z-depth reached 66 µm before exceeding the working distance of the objective. Oocyst depth could not be measured, as it exceeded the image z-depth. b The same oocyst imaged using a 40 × water-immersion objective with a longer working distance. Using this imaging setup, the oocyst depth was measured at 144 µm. The blue line indicates the z-axis position of the z-slice depicted in the X–Y projections, while the orange line represents the maximum z-depth imaged using the 63 × objective. Scale bar = 50 µm