Fig. 2.

Micro-computed tomography (micro-CT) detects CaOx crystals in Drosophilia (A) CaOx crystals (“stone”) are detected in oxalate-fed Drosophilia (Ox-fed) but not controls (Ctl). As with human CT, micro-CT reveals Ca-opaque spots (CaOx-monohydrate and dehydrate based on analysis in Fig. 5 and Supplemental Fig. S2). After 36 h of oxalate-supplemented food, crystals can be observed by birefringence (as in Fig. 4B). Knowing this, whole flies (3 Ox-fed and 2 Ctl) were fixed with ethanol, air dried, and then attached to polyethylene tubing. The entire assembly was embedded in wax (to prevent dehydration and movement of flies), then scanned over 24 h using micro-CT with a voxel resolution was 6 μm. Image is a maximum intensity display which shows the calcium (white) nicely but suppresses the “soft” tissue information (bodies of the flies). These experiments have been repeated at least three times with similar results. B: surface rendering of micro-CT image for fly 3. Botttom: images include the density extremes: low density (air sacs) and high density (CaOx).