Ribbons electron micrographs

Fig. 11. Scanning electron micrograph showing the intersection of primary shear bands with the glassy ribbon surface produced by simple bending.

Figure 5.3 Electron micrographs of diastereomers of A-octyl-D-aldonamide (a) helical rods from D-Glu-8 (1, bar = 50 nm), (b) rolled-up sheets from D-Man-8 (2, bar = 300 nm), and (c) twisted ribbons from D-Gal-8 (3, bar = 300 nm). Reprinted with permission from Ref. 31. Copyright 1990 by the American Chemical Society.

Figure 5.16 Cryo-transmission electron micrograph of (a, b) helical ribbons and (c, d) multi-lamellar tubules in aqueous dispersions of A-dodecanoyl-L-serine (28) at pH 6.4 (a-c) and 4.9 (d). Reprinted with permission from Ref. 79. Copyright 2001 by the American Chemical Society.

Figure 5.21 Transmission electron micrographs showing right-handed helical ribbons of L-Glu-Bis-3 (37) in aqueous environment. Reprinted with permission from Ref. 97. Copyright 2002 by Elsevier Science.

Figure 5.38 shows electron micrographs of the nanotubes and ribbons in this system. While these nanotubules were transformed into the ribbon gel after a few hours at ambient temperature, they appeared to be stable at 4°C. 

Figure 5.38 (a) Negative-stained transmission electron micrograph of nanotubules formed from equimolar mixture of DCg PC and DNPC (2 mM total lipid concentration) stored at 4°C just prior to deposition, (b) Freeze-fracture electron micrograph of twisted ribbons at 27°C. Bars = 100 nm. Reprinted with permission from Ref. 153. Copyright 2001 by the American Chemical Society. 

Figure 5.40 Electron micrographs of extended ribbon structure from DMPA (44) in 50 mM Tris-HCl buffer (pH 8.0) (a) after aging at 25°C and (b) gel of ribbons after aging at 25°C for 1 month. Bars = 0.1 p,m. Reprinted with permission from Ref. 157. Copyright 1992 by the American Chemical Society.

Fig. 2. Electron micrographs highlighting the polymorphism of amyloid fibrils. (A) A single human calcitonin protofibril with a diameter of 4 nm (adapted from Bauer et al., 1995). (B) Different morphologies present in a transthyretin fibril preparation. Black arrowheads show oligomers of different sizes, the black arrow points to a 9- to 10-nm-wide fibril, and the white arrowhead marks an 4-nm-wide fibril (adapted from Cardoso et al., 2002). (C-F) Human amylin fibril ribbons (adapted from Goldsbury et al., 1997). (C) A single 5-nm-wide protofibril. (D-F) Ribbons containing two (D), three (E), or five (F) 5-nm-wide protofibrils. (G) A twisted ribbon made of four 5-nm-wide protofibril subunits of Api-40 (adapted from Goldsbury et al., 2000b). Scale bar, 50 nm (A-G).

Figure 7-8 (A) Electron micrograph of the rod-shaped particles of tobacco mosaic virus. Omikron, Photo Researchers. See also Butler and Klug.42 (B) A stereoscopic computer graphics image of a segment of the 300 nm long tobacco mosaic virus. The diameter of the rod is 18 nm, the pitch of the helix is 2.3 nm, and there are 16 1 3 subunits per turn. The coat is formed from 2140 identical 17.5-kDa subunits. The 6395-nucleotide genomic RNA is represented by the dark chain exposed at the top of the segment. The resolution is 0.4 nm. From Namba, Caspar, and Stubbs.47 (C) A MolScript ribbon drawing of two stacked subunits. From Wang and Stubbs.46...

Figure 30-10 (A) Schematic drawing of a synapse. (B) Electron micrograph showing the synaptic junctions in the basal part (pedicle) of a retinal cone cell of a monkey.403 Each pedicle contains synaptic contacts with 12 triads, each made up of processes from a bipolar cell center that carries the principal output signal and processes from two horizontal cells that also synapse with other cones. A ribbon structure within the pedicle is characteristic of these synapses. Note the numerous synaptic vesicles in the pedicle, some arranged around the ribbon, the synaptic clefts, and the characteristic thickening of the membranes surrounding the cleft (below the ribbons). Micrograph courtesy of John Dowling.

FIGURE 14.9 Freeze-fracture electron micrograph of the ribbon-like amphotericin B lipid complexes. (From Bangham (1992). With permission.)... 

Figure 4 Self-assembling structures and liquid crystalline phase behavior observed in solutions of Pu-2 in water with increasing peptide concentration c (log scale). Electron micrographs (a) of ribbons (c = 0.2mM), (b) and (c) of fibrils (c = 6.2mM), and (d) fibers. The curves in (e) were calculated with the generalized model described in the text (see also Figure 5d). The polarizing optical micrograph (f) shows the thick thread-like texture observed for a solution with c = 3.7mM in a 0.2 mM pathlength microslide ...

Single chain amides with amino acid head groups and alkyl chains of various lengths have also been shown to form helical rods, twisted ribbons and straight tubules. These assemblies show no regular pitch in electron micrographs and... 

Fig. 2. Structure of E. coli ClpAP. (A) Side view of ClpA Pu reconstructed from electron micrographic data (Beuron et al., 1998). (B) Top view of the ClpAf, model (Beuron etal., 1998). (C) Cutaway view of the model ofClpA P (Beuron etal., 1998). (D) Structure of ClpP ]4 shown in a ribbon diagram (Wang et al., 1997). (E) Cutaway view of model of ClpPj4 (Reprinted from Larsen and Finley, 1997, with permission of Elsevier Science).

Figure 4.5.11 Electron micrograph of (a) iV-octyl-D-mannonamide scrolls, (b) iV-octyl-D-galactonamide twisted ribbons, and (c) galacton-gluconamide 1 1 mixture tubules.

Figure 17.2 (a) Transmission electron micrograph showing the ribbons of approximately 60 nm widths (b) on the left,... 

Fig. 2 Electron micrograph of AT-octyl-D-gluconamide self-assembled fibers and 3D model of four entwined ribbons [71,72]. Image kindly provided by Dr. BOttcher...

Fig. 41. Scanning electron micrograph showing the tensile fracture appearance of Alg YgNij amorphous ribbon.

Figure 8 displays a transmission electron micrograph of a dried dispersion of fully polymerized PTFE. This micrograph reveals the globular nature of common, commercial PTFE particles. More detailed studies on these particles revealed that these entities are not polycrystalline, but, in fact, are ribbon, or rodlike extended chain crystals that are wrapped around themselves in a more or less random manner (23). 

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