Pteridine autofluorescence

Prepare diluted ammonia solution (with 0.1% β-mercaptoethanol, pH 10.0). Dissect fish fin and plated it on the imaging dish/slide. Add ammonia solution to the fin and incubate for 5 min. Get rid of excess solution and image under Dapi channel. You would see fluoresence intensity gets stronger as exposed to UV light. Method adopted from references: Mutations affecting xanthophore pigmentation in the zebrafish, Danio rerio. Development, 1996 Dec;123:391-8. doi: 10.1242/dev.123.1.391. You could also check this reference for more pteridine staining and imaging aproaches in zebrafish: Analysis of Xanthophore and Pterinosome Biogenesis in Zebrafish Using Methylene Blue and Pteridine Autofluorescence. Pigment Cell Res. 2002 Feb;15(1):27-31. doi: 10.1034/j.1600-0749.2002.00045.x.