Fig. 6: PRM-SRS imaging of Drosophila fat body cells detects different lipid subtypes and their subcellular distributions.
a Maximum intensity projection (MIP) of the PRM-SRS hyperspectral image of total lipids reveals lipid droplets. b PRM-SRS detected TAG in lipid droplet cores. c Lysosome-like structures detected by PRM-SRS using reference spectra measured from lysosome-like structures in Drosophila fat body. d PE:TAG ratiometric images show that the interstitium between lipid droplet cores and lysosome-like structures has higher relative levels of PE. e PRM-SRS subtype images are merged to detect co-localization of different lipid subtypes. f Similarity scores from areas marked by red arrows 1 and 2 in the lower part of panel D highlight the necessity of evaluating relative concentrations as opposed to absolute concentrations. g SRS spectra of top 90th percentile pixel similarity scores in (b–d) lipid subtypes with respective standard reference spectrum overlaid. Center-line of spectra represent mean with 1 standard deviation (SD) error bands. h Intensity profiles along the dotted white lines in (a) and (e), upper and lower panels respectively, show how signal intensity varies with spectral shape, rather than concentration in a PRM-SRS image. n = 2 replicate trials. Scale bar, 20 µm. MIP maximum intensity projection, TAG triacylglyceride, PE phosphatidylethanolamine. Source data are provided as a Source Data file.
