Fibril electron micrographs

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).

The muscle fibrils are embedded in sarcoplasm, each individual fibril showing the banding pattern of the whole fiber (Bowman, 1840). Myosin could be extracted from muscle with strong salt solutions. From the altered appearance of the bands after extraction it was suggested that this protein was a major component of the A bands (Kuhne,1864 Danilewsky, 1881). The localization of myosin in the A bands and of actin in the I bands was convincingly shown by Jean Hanson and Hugh Huxley (1954-1955) in electron micrographs of transected fibers and confirmed after selective extraction to remove myosin (Hasselbach, 1953 Hanson and H.E. Huxley, 1953-1955). 

Fig. 2.4 Chrysotile asbestos sectioned perpendicular to the fiber axis. Electron micrograph showing typical lattice images of the layers of this serpentine mineral rolled into hollow cylinders (fibrils).

Fig. 13. Scanning electron micrograph of polyacrylonitrile fibrils formed by spraying a 0.05 wt % polyacrylonitrile in dimethylformamide solution into C02 through a 50-/mi inner diameter, 18-cm-long nozzle at a temperature of 40°C, density of 0.66 g/mL, and solution flow rate of 0.36 mL/min (118).

As manufactured, PTFE is of two principal types dispersion polymer, made by suspension polymerization followed by coagulation, and granular PTFE, polymerized and generally comminuted to a desirable particle size. Some details are given by Sperati. We have observed cast films of an aqueous colloidal dispersion and see that it consists of peanut-shaped particles, approximately 0.25 pm in size, which are composed of even finer particles. Electron micrographs of as-polymerized granular particles show three structures bands arranged in parallel, striated humps, and fibrils, some of which have the shish-kebab structure."... 

Figure 29-10 Schematic diagram of collagen molecules in a fibril so arranged as to give the 640-A spacing visible in electron micrographs...

An electron micrograph of collagen fibrils from skin. (Courtesy of Jerome Gross, Massachusetts Genera] Hospital.)... 

Fibril arrangements in the cell wall of Valonia (12,000 X), (Electron micrograph from A. Frey-Wyssling and K. Miihlethaler, Ultrastructural Plant Cytology, Elsevier Science Publishers, Amsterdam, 1965, p. 298. Reprinted with permission from Elsevier Science Publishers.)... 

Ronziere, M-C., Herbage, B., Herbage, D., and Bemengo, J-C. (1998). Fourier analysis of electron micrographs of positively stained collagen fibrils Application to type I and II collagen typing. Int. J. Biol. Macromol. 23, 207-213. 

Fig. 1. (A) Scanning electron micrograph of human skin. The epidermis has pulled away from part of the basement membrane. (B and C) Transmission electron micrograph through the epidermal-dermal junction of human skin. Keratinocytes (KF) are the cells in the human epidermis. LD, The lamina densa of the basement membrane LL, the lamina lucida. Typical anchoring fibrils (AF) formed from type VII collagen are shown at higher power in C. Courtesy of Dr. K. Holbrook, University of Washington.

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 ...

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