Keratins electron microscopy

Marshall, R. C Orwin, D. F. G., and Gillespie, J. M. (1991). Structure and biochemistry of mammalian hard keratin. Electron Microscopy Research 4,47-83. 

Moreover, prolonged heating will actually cause new links to form which anchor the molecules fhmly in their new position, a transition from cx-keratin to 3-keratin. Electron microscopy. X-ray diffraction and other forms of evidence indicate that about one-third of the total length of the protein chains in wool is in the coiled-coil, oc-helix conformation. 

Marshall, R.C., Orwin, D.F.G., and Gillespie, J.M., Stmcture and Biochemistry of Mammalian Hard Keratin , Electron Microscopy Reviews, 4, 47-83, 1991. 

Kunert, J. and Krajci, D. (1981). An electron microscopy study of keratin degradation by the fungus Microsporum gypseum in vitro. Mykosen 24, 485-496. 

Mercer, E. H., The electron microscopy of keratinized tissues, in The Biology of Hair Growth, Montagna, W. and Ellis, R. A., Eds., Academic Press, New York, 1958, 91. 

Fibrous protein structure investigations applying X-ray diffraction and electron microscopy were reviewed by Blakely (31). Keratin fibers are made of three main structural components the cuticle, the cortex, and the medulla. The medulla is only present in coarse fibers. The cortex forms the bulk of the fiber. Various morphological models have been proposed to explain the mechanical properties of keratin fibers. It is generally agreed that the cortex consists of fibrils in which protein molecules exist in helical and nonhelical regions. 

Brody, I., The Keratinization of Epidermal Cells of Normal Guinea Pig Skin as Revealed by Electron Microscopy, J. Ultrastruct. Res. (1959) 2, 482. 

Sarcomatoid carcinoma, also referred to as carcinosarcoma, spindle cell carcinoma, blastoma, and teratocarci-noma, are neoplasms of epithelial derivation that show variable differentiation. Sarcomatoid carcinoma has been reviewed conceptually by Wick and Swanson. Several studies have evaluated sarcomatoid carcinoma by immunohistochemistry using keratin antibodies and/ or electron microscopy. These studies concluded that the spindle cell component of the neoplasm was of epithelial derivation. In most instances, the spindle cells coexpress keratin and vimentin (Figs. 12.10 and 12.11) or occasionally keratin and other intermediate filaments such as desmin or actin. 

Kahn HJ, Thorner PS, Yeager H, et al. Immunohistochemical localization of pre-keratin filaments in benign and malignant cells in effusions Gomparison with intermediate filament distribution by electron microscopy. Am J Pathol. 1982 109 206-214. 

Keratin has a crystallinity of about 30 Z. Since 1950,X-ray diffraction and electron microscopy have led to a model in which the structural elements are (13,14) the a-helix with a diameter of 10, the elementary fibril containing two to three helicoidal chains of 20 diameter, the microfibril or association of ten elementary fibrils through the amorphous regions (of 80 A diameter) and finally the fibrils or structures of several microfibrils within an amorphous matrix. 

Electron microscopy of the stratum comeum does not give the ability to distinguish between the proteins produced during normal keratinization and those of psoriatic and ichthyotic scale. In psoriatic scale (Figure 7.4A),... 

Thus, clinically very similar types of inherited ichthyoses may be separated by their distinctive morphologic differences It may be expected that future ultrastructural studies will reveal the existence of further heterogeneities in the inherited ichthyoses. Moreover, electron microscopy has become a valuable tool in their exact diagnosis and is of great importance for our understanding of the kind of disturbances that lead to these types of inborn errors of keratinization . 

---