A Comparative Study of Fat Storage Quantitation in Nematode Caenorhabditis elegans Using Label and Label-Free Methods
Figure 2
Label and label-free imaging methods to assay fat storage in C. elegans.
(A) Labeled imaging of fat stores using Sudan Black, Oil Red O, and Nile Red staining of fixed worms and Nile Red and BODIPY-labeled fatty acids fed to live worms. (B) Label-free visualization of neutral lipid species and autofluorescent gut granules using simultaneous CARS and TPEF imaging, respectively. Note the co-localization of TPEF signal with CARS signal in the intestinal cells. Images are presented as 3-D stacks of 30 frames taken at 1 µm increment along the vertical axis. Rightmost panel is an enlargement of the overlaid image with the xy dimensions of 20 µm×20 µm. It should be noted that the association of fluorescent signal with lipid signal can be found surrounding, at one end, above, or below the lipid signal. In addition, the lipid contents of the fluorescent particles vary from one to another. For the particular image presented, the fluorescent puncta do exhibit lipid signal when examined at a higher magnification.