Fig. 2.

Tissue sections and permeabilization time. a–c) Frozen tissue sections, 10 µm, of operculum, skin, and fin samples were sectioned onto Visium expression slides and stained with H&E. Abbreviations: Epithelium (Epi), loose connective tissue (Lct), dense connective tissue (Dct), mucous cell (Mc), bone (Bo), and mesenchyme (Mes). Capture spot diameter and center-to-center distance are indicated in a. d) Fluorescent cDNA print of pectoral fin (10 min optimization time). Insert with higher magnification shows epithelial tissue with mature mucous cells displayed as circles with low fluorescent signal. e and f) Similar to d with 20 and 25 min permeabilization time. The intensity of the fluorescent signal indicates cDNA/mRNA yield. At all timepoints, the intensity of the fluorescent signal was higher in the epithelial layer when compared with the dermal layer.