Fig. 2: pan-ExM-t reveals mouse brain tissue ultrastructure.
From: All-optical visualization of specific molecules in the ultrastructural context of brain tissue
a, NHS ester pan-stained tissue section of the mouse cortex. b,c, Magnified areas in the black and dotted black boxes in a, respectively. d–h, Magnified areas identified by the correspondingly colored boxes in b,c showing putative excitatory synapses. i, Linear expansion factor (n = 254 measurements from 3 independent experiments, corresponds to data shown in a–h). j, ECS + lipid membrane (ECS+) fraction (n = 14 measurements from 3 independent experiments). k, Image of neuropil in the hippocampus. l, Same area as k where white pixels represent the ECS+ fraction. m–cc, Putative excitatory synapses defined by a prominent PSD. Lime arrows in n and o point to mitochondria in the presynaptic bouton and in the postsynaptic compartment, respectively. The salmon arrow in q points to a spine neck. dd–ii, Putative spine apparatuses (pink arrows) in the postsynaptic compartment defined by a characteristic lamellar arrangement. jj–ll, Classification of synapses based on the patterns and intensity of the PSD. jj, Type I (asymmetric) synapses where the PSD is prominent and macular. kk, Type I (asymmetric) synapses where the PSD is prominent and perforated. ll, Type II (symmetric) synapses, where the PSD, unlike DPs, is thin or barely visible. mm–vv, NHS ester pan-stained multisynaptic boutons and their postsynaptic partners. ww, Lateral view of a centriole showing distal and proximal ends as well as distal appendages (turquoise arrows). xx,yy, Top views of centrioles showing the cartwheel structure (xx) and the ninefold symmetry of microtubule triplets (yy). zz–nnn, Mitochondria with vesicular cristae (zz–ccc,ggg,iii), lamellar cristae (ddd–fff) and teardrop-shaped with tubular extensions (yellow arrows) (jjj–nnn). Salmon arrow in lll points to putative myelinated sheaths. ooo, Brain capillary showing endothelial cells (lavender arrow heads), putative tight junctions (TJs; teal arrows) that link neighboring endothelial cells, putative pericyte branch (salmon arrow) and the basement membrane (yellow arrow). Medians and interquartile ranges are shown with whiskers drawn down to the minimum and maximum values. Panels showing pan staining are displayed with a white-to-black color table. Gamma corrections: a,ww–yy,ooo, γ = 0.7; m–vv,zz–nnn, γ = 0.8. All scale bars are corrected for the expansion factor. Scale bars: 5 µm (a), 1 µm (b,c,ooo), 200 nm (d–h,m–cc,jj–vv,xx,ww,zz–ccc,ggg,jjj,kkk), 3 µm (k,l), 100 nm (dd–ii,xx,yy,ddd–fff,iii,mmm; 400 nm (hhh,lll,nnn). Expansion factor for m–ooo: 21.3 ± 1.5.
