The Nature has created a great number of materials with fascinating properties. Technologists can only dream of some of such materials. For example, look at an ordinary cobweb. Amazingly, but these fragile silk threads are five times more resistant to rupture than steel is. These threads, which are not very dense, are capable to stretch over one third of their length. Actually, this is true for only one kind of cobwebs, so called base thread, which is the strongest and the thickest (about five microns). Threads of this kind are the frames of spider catching nets. A female spider can produce seven sorts of cobweb silk that are excreted by different glands made use of in different ways, that is why their structure and properties differ greatly. The thread is very strong: it could stop a swiftly flying insect; while the spider (some of them are rather big) hangs up on this invisible safety rope and never ruptures it.
Material with such properties is sure to be important to the people. It would be perfect for parachute chords, body armours and many other things. Above that, it could be used in medicine as stitch material for microsurgery or as a material for strong and elastic artificial cords and tendons, which are not rejected by the body. One may say "Take a thousand of spiders and let them make their cobwebs". But spiders will not do. This work takes them too much energy and they have to revive for several days, after each thirty up to thirty-five meters of cobweb have been produced. And that all not mentioning the fact that spiders do not live in one can; they would have simply eaten each other then.
On the other hand it is impossible to synthesise this material. The investigations conducted at many laboratories around the world showed that spider silk is a complex composite material, containing two kinds of proteins and 5-6 % of water. Protein molecules are bound together in a very complicated way. One part of the protein is amorphous and another part (from 30 up to 45 %) is crystalline. The former ensures the elasticity and the latter is responsible for the strength. It is impossible to make such material by hand. The only way to produce it is to use biotechnology.
A team of scientists at the State Research Institute of Genetics and Selection of Industrial Microorganisms headed by Professor Vladimir G. Debabov and Dr Vladimir Bogush has decoded the gene responsible for producing the cobweb protein of a big spider from the Far East. Then the scientists managed to synthesise an analogue of this gene, though not completely similar to the natural one. After the scientists had inserted the synthesised gene into the genome of saccharomycetic yeast, the microorganisms started producing the cobweb protein.
The scientists managed to get a sufficient amount of the protein out of the yeast and to purify it. They found the appropriate solvent and made tiny films on glass plates, which then were thoroughly studied. The investigation showed that the films contain structures similar to the natural cobweb. In other words, the scientists managed to produce the analogue of the natural composite material.
This is the first step towards the industrial technology, which will allow manufacturing the tiny protein threads by passing through spinners that really remind spider spinning organs. The scientists at the Research Center "Uglechimvolokno" (Mytyshy) have been working out the technology of spinning.
Meanwhile, biotechnologists have been trying to synthesise the gene completely (as possible) reproducing the natural one, so that the protein produced by the yeast should be the exact copy of the cobweb silk in all respects.
The study is supported by ISTC.
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