Mulberry silkworm

Zhou, L., Chen, X., Shao, Z.Z., Huang, Y.F., and Knight, D.P. "Effect of metallic ions on silk formation the mulberry silkworm, Bombyx mori". ]. Phys. Chem. B, 109(35), 16937-16945 (2005a). 

Silk is a continuous protein niament spun by the silkworm to form its cocoon. The principle species used in commercial production is the mulberry silkworm, which is the larva of the silk moth, Bombyx mori. It belongs to the order Lepidoptera. 

Silva, S.S., Popa, E.G., Gomes, M.E., Ohveira, M.B., Nayak, S., Subia, B., Mano, J.F., Kundu, S.C., Reis, R.L., 2013. Silk hydrogels from non-mulberry and mulberry silkworm cocoons processed with ionic hquids. Acta Biomaterialia 9 (11), 8972—8982. 

Mai-Ngam, K., Boonkitpattarakul, K., Jaipaew, J., Mai-Ngam, B., 2011. Evaluation of the properties of silk fibroin films from the non-mulberry silkworm Sarnia cynthia ricini for biomaterial design. J. Biomater. Sci. Polym. Ed. 22, 2001—2022. 

R. K. Datta, K. Sengupta, and S. K. Das, Induction of dominant lethals with ethyl methanesulfonate in the male germ cells of mulberry silkworm, Bombyx mori, L., Mutat. Res. 

Silk is a natural protein fiber. The best known type of silk is obtained from cocoons made by the larvae of the mulberry silkworm Bombyx mori. The shiny appearance of silk is due to the triangular prism-like structure of the silk fiber, which allows the fibers to refract light at different angles. 

A few caterpillars which produce silk occur naturally in the wild depending on the forest trees. Such a silk which is obtained from the wild silk worms is referred to as wild silk and such worms are Antheraea mylitta, Antheraea paphia, Antheraea assamensis, etc. Antheraea mylitta (A mylitta ) is one of the wild varieties of non-mulberiy silkworm which produces Tassar silk. A few other wild silks are Mopani silk from South Africa, Saturniidae silk from Thailand, Assam silks (Muga, Eri and Pat] and Tassar silk from India and China. Six million people in India alone are involved in sericulture and one of the most economically important species for sericulture in India is the wild-type non-mulberry silkworm. 

Silks are fibrous protein, some forms of which can be woven into textiles. The best known type of silk have a range of functions, including cocoons of the larvae of the mulberry silkworm. Bombyx mori are reared in captivity [41, 143, 145]. They have repetitive protein sequence [29] with a predominance of alanine, glycine and serine (which is high in silkworm silks but low in spider silks). Silk proteins are comprised of four different structural components (1) elastic [3-spirals, (2) crystalline P-sheets rich in alanine, (3) tight amino acid repeats forming a-helices, and (4) spacer regions [47, 126]. 

Hakimi, O., Knight, D. P, Volhath, R, Vadgama, P. Spider and mulberry silkworm silks as compatible biomaterials. Journal of Composites Part B Engineering, 2007, 38(3), 324-337. 

The feeling of a spider web may be unsettling, but a similar natural material has been used for centuries to make silk fabric that is prized for its smooth texture. Silkworms produce the silk fibers used to make clothing. They feast on mulberry leaves and convert the molecules from these leaves into silk, from which they spin cocoons. 

The ancient Chinese discovered how to harvest silkworm cocoons, boil them to loosen the tangle, and unravel the silk into a fiber from which elegant clothing could be produced. A single silkworm cocoon can yield nearly a mile-long filament of silk, but the filament is so fine that it takes around 30 mulberry trees to yield enough cocoons to make one kilogram of silk. 

FIGURE 24.1 The pathway of carotenoid transport in the silkworm. Carotenoids are absorbed from dietary mulberry leaves into the intestinal mucosa, transferred to the hemolymph (1), transported in the hemolymph by plasma lipoproteins (2), and accumulated in the silk gland (3). 

Asano N, Yamashita T, Yasuda K, Ikeda K, Kizu H, Kameda Y, kato A, Nash RJ, Lee HS, Ryu KS. (2001) Polyhydroxylated alkaloids isolated from mulberry trees Moms alba L.) and silkworms Bombyx mori L.). J Agric Food Chem 49 4208-4213. 

The early work focused on a particular silkworm, Bombyx mori, that lives on mulberry bushes. There are other silkworms each with its own special properties, but in general most silk is still derived from the original strain of silkworm. Crystalline silk fiber is about four times stronger than steel on a weight basis. 

Rayon is made from cellulose. Count Chardonnet made the synthetic fibre from mulberry leaves. Chardonnet was studying the diseases of the silkworms. He was inspired by the silkworm spinning silk to find a way to make artificial silk. He made artificial silk from the cellulose he obtained from mulberry leaves by a complex process. 

O-a-D-galactopyranosylcalystegine B2 (22) and 3p,6p-dihydroxynortropane (23), were isolated from the fruits of M. alba [12]. DNJ is present in high concentrations in all parts of the mulberry tree. Interestingly, silkworms feed exclusively on its leaves and appear to accumulate DNJ in their bodies since the DNJ content in silkworms is 2.7-fold higher than that in the leaves [12] (Figure 5.1). 

There are all sorts of silk that are found in nature. The stuff that is usually found in textiles comes from silkworms (Bombyx mori). They are not really worms, but the larvae of moths. They emerge from very small eggs with an incredible lust for mulberry leaves, which they consume until they are ready to. pupate and weave a cocoon around themselves. Unlike spiders, which spin silk from their rear end, silkworm silk is actually hardened saliva, which comes out of the mouth. The larva has a small spinneret on its lip, through which the silk emerges. The cocoon is formed from a single strand of silk that... 

The family Moraceae was named after the mulberry. Modus. The red mulberry. Modus rubra, is native to North America, where it occurs in moist woodlands. It produces a tasty, juicy fruit which is favored by birds, and although it is also good for people to eat, it is not economically important. The white mulberry. Modus alba, is native to Asia. In China, leaves of the white mulberry are fed to cultivated silkworms, a type of moth larva. The white mulberry became naturalized in North America during unsuccessful attempts to establish a silk industry in colonial America. Unlike the native red mulberry, the white mulberry is somewhat weedy, and is often found around homes, in disturbed sites, along fencerows, and in moist, second-growth bottomlands. Fruits of the white mulberry may be white, pink, red, or deep purple. The dark purple fruits inspired the name Modus nigra, although taxonomists have since determined this plant to only be a variety of Modus alba. 

The mulberry plant was venerated because it was the food upon which silkworms fed, and silk was one of China s most important products. But silk was very expensive and only the very wealthy could afford silken fabric. For the vast millions of less fortunate, cheaper material had to be found. Such material was typically hemp. 

This is the term applied to the cultivation of silkworms. The first essential for success is a good stock of mulberry trees. The eggs are hatched in incubating rooms which are maintained between 20° and 25°C (68° and 77°F). As the worms hatch they are transferred to frames where they are fed on chopped mulberry leaves. Plenty of fresh air and cleanliness are essential for the well-being of the worms because they are subject to many diseases, these being one of the great hazards of sericulture. Pasteur studied the causes of sickness in silkworms, and this particular work was a part of... 

Traditional rearing of silkworms has been in practice in the country for centuries as silk continues to remain a sought-after commodity from India. The Department of Biotechnology has been supporting a number of projects in mulberry and non-mulberry sericulture. A few important features of such efforts are briefly described below. 

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