Journal: The journal of histochemistry and cytochemistry : official journal of the Histochemistry Society

Article Title: Quantum dot immunocytochemical localization of somatostatin in somatostatinoma by Widefield Epifluorescence, super-resolution light, and immunoelectron microscopy.

doi: 10.1369/0022155412459856

Figure Lengend Snippet: Figure 4. (A) Super-resolution light microscopy image of somatostatin labeling with streptavidin 525-nm quantum dots (QDs) in a 500- nm semithin epoxy section acquired in 3D-SIM mode. The 100-nm resolution of this microscope resolved the irregular distribution of somatostatin in individual secretory granules. Labeling can be seen to be variable with areas of high and moderate fluorescence (arrows). Intensely stained 500- to 600-nm ring-shaped or “doughnut-like” structures in the cytoplasm (square box) and some nonspecific staining in nuclei (colored blue) may also be seen. Super-resolution imaging of QD probes is possible due to their high photostability and strong fluorescence signal. Objective was ×100 with oil immersion and excitation was with a 488-nm laser (monochrome image with false color). (B) Transmission electron microscopy image showing 500- to 600-nm sized granules with electron-dense material at their margins (arrow) thought to correspond to ring-shaped fluorescent structures. (C) Higher power view of a 500-nm secretory granule with electron-dense material inside the limiting membrane (arrows). Scale bars: A = 8 µm, B = 6 µm, C = 500 nm.

Article Snippet: Superresolution fluorescence microscopy in the present study was performed using a Nikon Ni Eclipse inverted microscope fitted with an N-SIM (Structured Illumination Microscopy) illuminator (Nikon Corporation; Tokyo, Japan).

Techniques: Light Microscopy, Labeling, Microscopy, Fluorescence, Staining, Imaging, Transmission Assay, Electron Microscopy, Membrane