Fig. 3

Distinct toxin distributions across the venom glands are taxonomically widespread in snakes. A pLSA analysis of MSI spectra from the venom gland of N. subfulva. The top spectrum shows the normalised across-tissue averaged spectrum in the m/z region corresponding to 3FTx—the dominant components of N. subfulva venom. The below centroid spectra are extracted from each group clustered by pLSA, where distributions across the gland are displayed as contrast-optimised heatmaps on the right. The H&E-stained section is shown at the top with an arrow indicating the direction of venom secretion. B Distributions of peaks corresponding to toxins with known activities are shown as contrast-optimised heatmaps. Accession numbers for cytotoxins are UniProt P01448, P01473, and P01474 and for neurotoxins, UniProt P01424, P01400, and GenBank GIJM01004310.1. C pLSA analysis of MSI spectra from the venom gland of C. rhodostoma. The top spectrum shows the normalised across-tissue averaged spectrum across the full acquired m/z range. The below centroid spectra are extracted from each group clustered by pLSA, where distributions across the gland are displayed as contrast-optimised heatmaps on the right. The H&E-stained section is shown at the top with an arrow indicating the direction of venom secretion. D Distributions of major peaks corresponding to the m/z values given below each image are shown as contrast-optimised heatmaps