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. 2020 Aug 29;23(9):101514. doi: 10.1016/j.isci.2020.101514

Figure 3.

Figure 3

FIB-SEM Analysis of Mitochondrial Protrusions in Neurons of the Mouse Nucleus Accumbens

(A) Selective micrographs showing the spatial progression of a mitochondrial protrusion (arrowheads) connecting to a nearby tubulovesicular structure. The z resolution of the FIB-SEM for the nuclear accumbens is 4 nm. The number on the micrograph indicates its z position in the SEM image stack. A complete stack of consecutive micrographs for this mitochondrial vesicle is shown in Video S1.

(B and C) Examples of mitochondrial protrusions. Note in (C), the mitochondrial protrusion touches a tubular structure (arrow).

(D–G) Additional examples of mitochondrial protrusions, all of which have a stubby neck (arrowheads). Arrow in (D) indicates the tip of the protrusion making direct contact with a nearby tubular structure. Arrow in (F) indicates a part of the protrusion contacting a structure that has the structural feature of a recycling endosome. Arrow in (G) indicates also the tip of the protrusion making contact with a tubular structure. A 3D reconstruction of this mitochondrial protrusion is shown, and a Video showing a complete EM image stack of this example is in Video S2.

(H) Percentage of mitochondria with protrusions. A total of 58 axonal mitochondria and 42 dendritic mitochondria were examined in their entirety in z dimensions. Additional examples of mitochondrial protrusions in the nucleus accumbens are shown in Figure S3. Scale bars, 100 nm.