Fig. 4: Cryo-XANES reveals differences in guanine spectrum within intracellular organelles.
From: pH variations enable guanine crystal formation within iridosomes
a, A cryo-XANES spectra of the nitrogen K-edge of a crystal (blue) and organelle (orange). b,c, Swarm graphs showing the ratio between π*2 and π*1 peaks of crystals (blue) and organelles (orange), using normal radiation dose (n = 143 organelles and n = 192 crystals from 25 different cells) (b) and using minimal radiation dose (n = 36 organelles and n = 52 crystals from 5 different cells) (c). Each data point represents an ROI within the XANES measurement field of view. The mean ± s.d. is indicated by horizontal bars overlaid on the swarm plot. Differences in ratios between categories were tested with a two-sided linear mixed-effects model, with category as a fixed factor and sample ID (cell number) as a random factor; P = 2 × 10−16 in b and P = 3.32 × 10−5 in c.
