Spider silk, types

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. 

Crystallinity. Generally, spider dragline and silkworm cocoon silks are considered semicrystalline materials having amorphous flexible chains reinforced by strong stiff crystals (3). The orb web fibers are composite materials (qv) in the sense that they are composed of crystalline regions immersed in less crystalline regions, which have estimates of 30—50% crystallinity (3,16). Eadier studies by x-ray diffraction analysis indicated 62—65% crystallinity in cocoon silk fibroin from the silkworm, 50—63% in wild-type silkworm cocoons, and lesser amounts in spider silk (17). 

Although spider and insect spinning silks are different and their silk types and functions diverse (Craig, 2003 Foelix, 1996), it is strongly... 

There are several reports of the use of silk in biomaterials. Kluge et al. (2008) provide a good overview of application of spider silks including recombinant versions. In addition to spider silks there are other types of silks that provide distinct and useful properties, such as those derived from mussels which will presumably become targets for recombinant protein production (Carrington, 2008). 

In man-made fibres, any stretching will irreversibly alter the crystallinity and there is no control of the lateral size of polymer crystals. Semicrystalline polymer networks typically consist of platelet type crystals whose width exceeds their thickness by several order of magnitudes because only the thickness is controlled by the chain folding [61]. In contrast to synthetic fibres, spider silk does not need any mechanical treatment by external forces the constituents self-assemble directly during the spinning-process. These examples clearly demonstrate the need for more detailed control of the mesoscopic structures for further development of man-made materials. 

Institute of Plant Genetics and Cultivated Plant Research in Gatersleben Human papillomavirus (HPV), Type 16 virus-like particles, spider silk, single chain antibodies 146-151... 

Types of Spider Silk Including the Gland Where They Are Synthesized and the General... 

Most silkworm cocoon and spider dragline silk fibers contain assembled antiparallel p-pleated-sheet crystalline structures [33-35]. Silks are considered semicrystalline materials with 30-50% crystallinity in spider silks, 62-65% in cocoon silk fibroin from the silkworm B. mori, and 50-63% in wild-type silkworm cocoons. In the -sheet erystals the polymer chain axis is parallel to the fiber axis. The extent to which these struetures form, as well as their orientation and size, directly impact the mechanical features of silk fibers. Furthermore, the polyalanine repeats or... 

Currently, it is believed that a new type of material having properties similar to those of spider silk should be produced using a genetic method. To do so it would be beneficial to study the physicochemical properties of spider silk in detail from the viewpoint of nanostructure. 

Both stretched and unstretched silk threads from the Black Widow spider were imaged. Two types of fibers were observed within the threads (thicker, 300 nm in diameter, oriented parallel to the thread axis thinner, 10-100 nm fibrils oriented across the thread axis). With increasing strain, mean fiber and fibril diameters were found to decrease and fibrils aligned themselves more closely with the thread axis. The authors were able to relate these structural features to models of secondary and tertiary structure and organization in spider silk (77). 

Baoyong, L., Jian, Z., Denglong, C., and Min, L. (2010). Evaluation of a new type of wound dressing made from recombinant spider silk protein using rat models. iJumi 36, 891-896. 

The functional and developmental details of the two so very different elastic recoil mechanisms of the two types of capture silk micro-machines are interesting and deserve deeper studies. However, at present we do not even understand the interaction of form and function in the much more typical spider silk fibre such as a dragline filament. Recent studies indicate that the toughness of spider dragline silk may depend on the complex hierarchical structure of the fibre [11] which in turn depends on a complex... 

As shown earlier, orb weavers like the garden spider Araneus or the golden silk spider Nephila coat the capture threads with an aqueous solution that forms sticky droplets. Coat and droplets are crucial for the function of these capture threads as their elasticity derives largely from the high water content of the coat. However, water is important not only for these threads, but for many other types of thread as well, and the role of water as well as other solvents for understanding and manipulating the mechanical properties of spider silk caimot be understated (Fig. 8.9). This can be of special interest if we aim to produce bio-engineered silks with specific properties. 

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