Silk of spider

Aspects of X-ray diffraction on single spider fibres. Int.J. Biol. Macromol. 24,179-186. Riekel, C., Mueller, M., and Vollrath, F. (1999b). In situ X-ray diffraction during forced silking of spider silk. Macromolecules 32, 4464-4466. 

The key components in all sophisticated biological materials are the macromolecules that the cells produce and subsequently incorporate into the material. These include proteins, glycoproteins, proteoglycans, lipid assemblies and polysaccharides. Many biological materials are composed almost entirely of these assembled macromolecules. Common examples are the cuticles of many insects, the skin and tendons of vertebrates or the silk of spider webs. A very widespread adaptation is to stiffen the material by the introduction of a mineral phase. Common mineralized biological materials include the shells of mollusks, the carapaces of crustaceans, and the bones and teeth of vertebrates. Many of them are composite materials and are known to possess remarkable mechanical properties, especially when taking into account that they form at ambient temperatures and pressures, and that their mineral components are often commonplace materials with rather poor natural mechanical properties... 

Here, it was of interest to compare whether the silk of spiders or the silk of silkworms are more resistant to ultraviolet rays. 

Nature frequently uses polymers for load-bearing applications as well (see also section 9.4.4). One particularly interesting example for a biological polymer is the silk of spiders or some insects, for example the... 

Bon, M. (1710-1712). A Discourse upon the Usefulness of the Silk of Spiders. By Monsieur Bon, President of the Court of Accounts, Aydes and Finances, and President of the Royal Society of Sciences at Montpellier. Communicated by the Author. Philosophical Transactions (1683-1775) 27, 2-16. 

Spider Silk. Spider silks function ki prey capture, reproduction, and as vibration receptors, safety lines, and dispersion tools. Spider silks are synthesized ki glands located ki the abdomen and spun through a series of orifices (spinnerets). The types and nature of the various silks are diverse and depend on the type of spider (2). Some general categories of silks and the glands responsible for thek production are Hsted in Table 1. 

Table 1. Function and Location of Spider Silk Glands ...

Simmons, A.H., Michal, C.A., Jelinski, L.W. Molecular orientation and two-component nature of the crystalline fraction of spider dragline silk. Science 271 84-87, 1996. 

This combination of strength and flexibility derives from the eomposite nature of spider silk. As keratin protein is extruded from... 

The complexity and versatility of materials made by nature are the envy of scientists. We are only beginning to be able to create materials that have the strong yet porous structure of bone or the strength and flexibility of spider silk (Section 19.13). However, some materials are not strong they are soft and flexible. These materials, some of which are described in the following two sections, are also important to industry and medicine and some are vital to life. 

Hayash C.I., Shipley N., and Lewis R., Hypotheses that correlate the sequence, structure, and mechanical properties of spider silk proteins, Int. J. Biol. Macromol., 24, 271, 1999. 

Parkhe AD, Seeley SK, Gardner K (1997) Structural studies of spider silk proteins in the fiber. J Mol Recognit 10 1-6... 

Figure 10 shows polarized spectra of two types of silks recorded by Raman spectromicroscopy the dragline silk (the lifeline) of the spider Nephila edulis and the cocoon silk of a wild silkworm Sarnia cynthia ricini. The position of the amide I band at 1,668-1,669 cm-1 for both threads is characteristic of the /i-sheet... 

Figure 10 Polarized spectra obtained by Raman microspectroscopy of (A) the dragline silk of the spider Nephila edulis and (B) the cocoon silk of the silkworm Sarnia cynthia ricini. Adapted with permission from Rousseau et al. [63]. Copyright 2004 American Chemical Society.

Examples. 2D SAXS/WAXS experiments on highly anisotropic polymer materials during melting and crystallization can be used to visualize and understand the evolution of nanostructure [56,57], Transformations of biopolymers in solution, e.g., virus crystallization can be studied in situ [58], It is possible to study solidification mechanisms of spider silk [59], or the self-assembly of micelles on a time-scale of milliseconds [60],... 

Production of Spider Silk Proteins in Transgenic Tobacco and Potato... 

Purification of Spider Silk-Elastin Fusion Proteins by Heat Treatment and Inverse Transition Cycling... 

Applications of Spider Silk-ELP Fusion Proteins in Mammalian Cell Culture... 

Nevertheless, despite our rapidly increasing knowledge about silk protein sequences, very little is known about the part played by gene design (Tatham and Shewry, 2000) in the stability and solubility of the prespun silk and in the final property of silk fibers across a wider variety of spiders and insects. 

Fig. 4. Time-induced conformational change of spider silk protein (spidroin) in solution. Solutions of silk proteins at 1% w/v in distilled water were monitored using circular dichroism. The graph shows a change in secondary structure with time. The silk proteins underwent a kinetically driven transition from a partially unfolded structure to a -sheet-rich structure (from Dicko et al., 2004c). ( ) after 0 days, (O) after 1 day, and (A) after 2 days. The conformational change appeared faster at 20°C compared to 5°C, suggesting a hydrophobically driven mechanism. (Copyright 2004 American Chemical Society.)...

Beek, J. D.v., Hess, S., Vollrath, F., and Meier, B. H. (2002). The molecular structure of spider dragline silk Folding and orientation of the protein backbone. Proc. Natl. Acad. Sci. USA 99, 10266-10271. 

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