听力文摘：蚕丝

（单词翻译）

Silk

蚕丝

Silk is the strongest natural fiber¹ in the world, as far as we know. Scientists long to understand just how exactly the silkworm manages the process of silk weaving, so they can replicate² the process in order to manufacture such things as high-strength and high-performance materials for sports and law enforcement.

蚕丝是史上全世界最强韧的天然纤维。长久以来，科学家想知道蚕如何产丝，然后仿效制丝过程，生产高强高性能的运动原材及执法材料。

Though our understanding of the silk-making process is not yet complete, scientists do know that the key to making silk lies in the animal’s careful managing of the water content in its silk glands³.

虽然我们对制丝的整个过程了解的不多，但是科学家可以肯定关键在于蚕如何细心掌控丝腺里的水分。

Silk gets its strength from its proteins. Parts of the proteins are hydrophilic, or water-loving; and parts are hydrophobic, or water-fearing. For some time it was a mystery how silkworms managed to convert these proteins into silk threads without the proteins crystallizing before the animal is ready to spin them. Premature⁴ crystallization would clog⁵ up their silk glands, which would likely prove fatal to the little creatures.

蚕丝的高强性是因为蛋白质。蛋白质部分是亲水的；部分是疏水的。蚕吐丝前，蛋白质尚未结晶，蚕是如何将蛋白质转换成蚕线一直是个未解之谜。而过早的结晶会阻塞丝腺，蚕很可能为此丧命。

The answer lies in the silkworm’s slowly decreasing the water content in its silk glands and in the proteins’ ability to retain water, keeping the solution soluble⁶ up until it is spun⁷. As the water decreases, the water-loving parts of the proteins fold together in chains, forcing the water-fearing parts together.

奥秘在于丝腺里的水分逐步流失，而蛋白质可以储存水分，蚕在吐丝前先溶解于水。水分渐渐流失，亲水的蛋白质丝丝缕缕缠绕在一起，将疏水的部分也裹在一起。

As the water level continues to drop, the folded chains of silk push together more and more to form larger and larger gel-like structures. All the while the water-loving parts retain enough water so that the solution does not crystallize prematurely⁸, before there is enough of the material to begin spinning.

水分继续流失，包裹在一起的蚕丝像滚雪球般形成凝胶状。亲水的蛋白质始终储存足够水分避免过早结晶。结晶后，蚕吐出蚕丝。