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pattern with the large central core of repetitive domains for mechanical strength

flanked by a non-repetitive N and C terminal domain helping in the fibre formation

during spinning. Dragline silk proteins were given much emphasis for the production

ofrecombinantsilkwhichdifferinthepercentageofprolineresidues.Someofthesilk

proteins like MaSp1, MaSp2 and AcSp1 from different sources of Nephella clavipes,

Araneus Diadematus, Arglope and Trifasciata were cloned in different organisms like

E. Coli, Salmonella, Yeast, etc. with recombinant protein product yields ranging from

40 to 300 mg/L. It has not been possible to breed spiders in the laboratory even today.

Hence, it is advisable to produce spider silk by DNA technology [19].

Summary

In this chapter, chitin composition and its applications have been discussed in some

detail. The role of resilin in insect flight and in the jumping process has been stressed.

Silk as a natural fibre thread giving details of its structure and compositions has been

mentioned. A mathematical approach has been attempted to understand the elastic

nature, energy stored or consumed and force exerted during its action in the resilin.

However, the availability of this fibre in the required quantity is a major problem.

The most significant aspect of spider silk is its strength and its bulletproof nature.

Hence, it is being used in the defence industry for making bulletproof jackets of

soldiers. A summarized comparison between spider and tasar silk moth from various

sources has been listed in Table 8.3.