Nephila clavipes

The first spinning experiments were performed with dissolved raw silk of the silkworm Bombyx mori [31] and the golden orb-weaver Nephila clavipes [32]. For this purpose a minimized wet-spinning apparatus was constructed [31]. The apparatus was capable of spinning fibers from solutions containing 10 mg of soluble protein. 

Raw silk was dissolved in hexafluoro-iso-propanol (HFIP) [17, 33]. A typical working concentration for spinning was 2.5% (w/v) silk fibroin in HFIP. The spinning solution was pressed through a small needle (0 80-250 pm) into a precipitation bath (methanol for Bombyx mori silk proteins and acetone for Nephila clavipes silk proteins) and the silk solution immediately precipitated as a fiber. The best performing fibers approached the maximum strength measured for native fibers of Bombyx mori, but did not achieve the mechanical properties of natural spider silk. 

Sponner, A., Schlott, B., Vollrath, F., Unger, E., Grosse, F., and Weisshart, K. (2005a). Characterization of the protein components of Nephila clavipes dragline silk. Biochemistry 44, 4727—1736. 

Nephila clavipes, silk from, 22 627, 628t, 632t, 633 Nephrotoxicity... 

From a defensive point of view, it was shown that sequestered PAs constitute an efficient protection against the orb-weaving spider Nephila clavipes, which liberates butterflies unharmed from its web. In this study, AT-oxides were shown to be more active than the corresponding free bases. This could be correlated with physicochemical properties of these molecules in interaction with the Nephila receptors. Moreover, there was a significant correlation between dosage and antipredator activity of PAs [160]. 

Higgins, L.E., Townley, M. A., Tillinghast, E. K. and Rankin, M. A. (2001). Variation in the chemical composition of orb webs built by the spider Nephila clavipes (Araneae, Tetragnathidae). Journal of Arachnology 29 82-94. 

Composition of the silk lipids of the spider Nephila clavipes. Lipids 36 637-647. 

Vasoconcellos-Neto, J. and Lewinsohn, T. M. (1984). Discrimination and release of unpalatable butterflies by Nephila clavipes, a neotropical orb-weaving spider. Ecological Entomology 9 337-344. 

Figure 12.3 Utetheisa ornatrix that were offered to the orb-weaving spider Nephila clavipes. The specimen on the right, rejected intact, was raised on one of its normal, pyrrolizidine alkaloid-containing food plants (Crotalaria mucronata). The one on the left, raised on an artificial diet devoid of alkaloid, was eaten. See also Figure 12.4. (From Eisner, 1982. American Institute of Biological Science.)...

Trivers R. L. (1985) Social Evolution. Benjamin Cummings, Menlo Park, CA. von Nickisch-Rosenegk E. and Wink M. (1993) Sequestration of pyrrolizidine alkaloids in several arctiid moths (Lepidoptera Arctiidae). J. Chem. Ecol. 19, 1889-1903. Vasconcellos-Neto J. and Lewinsohn T. M. (1984) Discrimination and release of unpalatable butterflies by Nephila clavipes, a neotropical orb-weaving spider. Ecol. Entomol. 9, 337-344. 

Fibroin (Bombyx mori) (ExPASy http //www.expasy.ch/) Spidroin (Nephila clavipe) (Shao et at, 2003)... 

Zarkoob et al. (1998, 2004) were the first to report on the electrospinning of silkworm silk and Nephila clavipes dragline protein. They used an HFIP solution of protein as the spinning dope. The resulting fibers had a wide distribution in diameter and the continuity during spinning could be significantly improved. 

Hinman, M.B., and Lewis, R.V. "Isolation of a Clone Encoding a 2nd Dragline Silk Fibroin - Nephila-Clavipes Dragline Silk Is a 2-Protein Fiber". J. Biol. Chem. 267(27), 19320-19324 (1992). 

Figure 8 (a) Schematic drawing of the proposed structure of the dry dragline silk of Nephila clavipes, consisting of /i-pleated nanocrystallites, connected via amorphous chains, (b) Simplificated model, investigated by Termonia [75], Reproduced with permission from [75]. 1994 American Chemical Society... 

Dependence of mechanical properties on the amino acid content in the silk of Nephila clavipes has been investigated using solid state NMR and amino acid analysis. ... 

Second viral coefficient molcm g Nephila clavipes spider dragline 3.0 X 10 (13)... 

Spider silk is composed of large polypeptides, 250-320 kDa. A 285 kDa protein from the spider Nephila clavipes was generated in E. coli and purified. Its structural properties were superior to smaller-molecular-weight proteins. The glycine-rich (44% of residues) protein was generated by increasing the pool of glycyl-tRNA [142]. 

Nephila clavipes silk produced naturally and through controlled silking. 

---