Silkworms produce spider silk

Researchers use caterpillars to produce spider silk

03/01/2012

A team of Chinese and American scientists has brought genetically modified caterpillars to produce a kind of spider silk. This could be the breakthrough in the production of artificial spider silk, according to Donald Jarvis, professor of molecular biology at the University of Wyoming, USA, in the latest issue of the journal „Proceedings of the National Academy of Sciences“ (PNAS).

The scientists injected the genome of the silkworms with a gene sequence with the instructions for a silk protein of the Golden Silk Spider (Nephila clavipes). Subsequently, the caterpillars produced fibers that actually contained proteins of the spider silk. The silk produced by the caterpillars was comparable in its elasticity and tensile strength with spider silk, according to the researchers in the magazine „PNAS“.

Produce spider silk with the help of caterpillars?
Spider threads are due to their special properties in medicine for a variety of uses such as a material for sutures or bandages particularly well suited. So far, however, spider silk can only be obtained by hand in extremely small quantities, and the animals' attitude is made considerably more difficult by the natural habits of the spiders, such as territorial behavior or cannibalism. Therefore, production of large amounts of spider silk seemed almost impossible. The efforts to create spider silk with the help of bacteria, insects or plants, failed, because in this mode of production did not produce the necessary threads. Caterpillars, however, are producing their silk in threads anyway, and the extraction of silk has been known for centuries.

So the Chinese and American scientists have taken advantage of the caterpillars to produce artificial spider silk with their help. By altering the genome, the instructions for building a silk protein of the Golden Silk Spider were implemented in the silk glands of the silkworms (Bombyx mori). The caterpillars then produced a hybrid silk, which contained only five percent spider proteins, but in its elasticity and tensile strength was quite comparable to spider silk, so the statement of Prof. Dr. med. Donald Jarvis and colleagues. Thus, the silkworms could possibly be used in the future for the production of hard silk fibers with spider silk proteins, the researchers said. „Spider silk has enormous potential as a biomaterial for a wide variety of applications“ and correspondingly high is the need for one „effective biotechnology approach“ for fiber production of spider silk, emphasized Prof. Dr. med. Jarvis.

Medical applications of spider silk
The US scientists call in their contribution a variety of possible applications of spider silk in medicine. According to Florence Teulé of the University of Wyoming, spider silk fibers have great potential as biomaterials for wound dressings, artificial ligaments, tendons, tissue scaffolds or microcapsules, for example. A more comprehensive use is hitherto prevented only by the very limited availability. However, the current discovery for hope of the researchers could help here. With the help of silkworms could avoid the existing difficulties in the production of spider silk and could be produced in the future significantly larger quantities, said the US scientists. (Fp)

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Picture: Erika Hartmann