Araneus diadematus

Kovoor, J., and Zylberberg, I. (1972). Morphologie et ultrastructure du canal des glandes ampullacees d Araneus diadematus Clerck (Arachnida, Araneae). Z. Zellforsch. Mikros-kop. Anat. 128, 188-211. 

ICommon] Garden spider. Araneus diadematus, a harmless orbitelous spider, has a white cross formed of guanine crystals on its back. These crystals are enclosed in guanocytes which are visible through the cuticule see also spider venoms. 

The first successful expression of cDNA clones of silks were with partial cDNA clones from N. clavipes major ampullate silk gland cDNA [76]. The 1.7-kb fragment was from the 3 -terminus of the major ampullate silk gene and a 43 kDa recombinant silk protein was expressed and characterized. Most recently, partial cDNA clones of the 3 end of spider silks cDNAs from Araneus diadematus were cloned and expressed in mammalian cells as part of an effort to develop transgenic animals that express silk proteins [77]. Transgenic expression of silks in plants (tobacco and potato) and mammalian epithelial cells has been reported [71,77] and may point the way toward more substantive production of these proteins in the future. 

Gosline, J.M., Poliak, C.C., Guerette, P.A., Cheng, A., DeMont, M.E. and Denny, M.W. (1994) Elastomeric network models for the frame and viscid silks from the orb web of the spider Araneus diadematus. In Siik Polymers Materials Science and Biotechnology, pp. 328-341, D.L. Kaplan, W.W. Adams, B.L. Farmer and C. Viney (Eds.). American Chemical Society, Washington, DC. 

Silk is an interesting biomateiial that has been used since ancient times. It is a protein polymer (consisting of various amino acids) that is spun into fibers by insects like the silkworm, spider, scorpion, mites, and flies. Depending on the source and the arrangement of amino acids, there are a variety of silks, each having specific properties. Some evolutionary advanced species of insects are capable of spinning as many as nine or more varieties of silk for different purposes such as cocoon construction, lines for prey capture, safety lines or draglines, web construction, and adhesion [29]. The most widely characterized silks include those from the domesticated silkworm (Bombyx mori) and from spiders (Nephila clav-ipes and Araneus diadematus). 

The mechanical properties of spider dragline silk are especially well-studied, mostly for the common garden spider Araneus diadematus and... 

The mechanical behaviour of radial and capture silks differs greatly. For example, the wet and soft sticky spiral of the Araneus diadematus garden spider absorbs energy by large extendibility circa 500%) of the wetted thread which develops substantial force only after 100-200% extension with... 

A capture thread of Araneus diadematus under increasing magnification. The windlass mechanism is seen in the lower picture where the core fibres after a large extension-contraction cycle have been reeled into a droplet (for details see ref. 12). 

The dry and very tough radius threads of orb web-building spiders such as Nephila spp. or Araneus diadematus show good extendibility (up to and... 

Kohler, T. and Vollrath, F., Thread biomechanics in the two orb weaving spiders Araneus diadematus (Araneae, Araneidae) and Uloborus walckenaerius (Araneae, Uloboridae). J. Exp. Zool., 1995, 271 1-17. 

The shells of shellfish consist not only of chitin. In the edible crab Cancer pagurus and the lobster Homarus americanus) the calcified, rigid parts of the exoskeleton also contain a series of proteins that are also found in the noncalcified, flexible regions. Most of these proteins have a molar mass below 20 kDa some of them seem specific to crustaceans but others are also present in some insects (Andersen, 1999). The cuticular proteins of the horseshoe crab [Limulus polyphemus) show similarities with those of other arthropods, in particular those of the spider Araneus diadematus, but their molar masses are lower (7-16 kDa) Dietzel, Andersen, and Hojrup, 2003). 

Figure 14.7 Silks from different sources exhibit a wide range of stress-strain properties. The examples shown are divided into three groups on the basis of their extensibility. (1) Anaphe moloneyr, (2) /Araneus ser/cafus dragline (3) Bombyx mori cocoon, (4) A. diadematus cocoon] (5) Galleria mellonella cocoon (6) A. sericatus viscid. (7) Apis mellifora larval (8) Chrysopa carnea egg stalk (9) Meta reticulata viscid. Data collected from various sources.

---