英語(yǔ)聽力文摘 植皮有新招
Silkworms and Skin Grafts
Don: One of the neater things that’s going on in biology is the genetic modification of species. By changing the instructions in their genes, we can make certain plants and animals produce things that are useful to humans.
Ya?l: Well, I guess people have been using animals and plants to produce things we can use for centuries. We drink cow’s milk, for example. And we make clothes out of cotton.
D: Very true. We also use silk.
Y: Yes, and silk is made by silkworms.
D: But genetic modification is a whole new ball game. For example, research being done at Hiroshima University has shown that your everyday silkworm can be genetically altered to produce a form of human collagen. They build it right into their silk.
Y: Cool! What's collagen?
D: Collagen is just a protein. It's important though because it happens to be the structural protein that goes into building your skin, tendons, ligaments, and even your bones.
Y: OK, so what would you actually do with it?
D: One thing you could do is use it to make skin grafts. Silkworms already spin about sixty thousand tons of silk every year, so if collagen-laced silk can be reliably produced, it would be a cheap and ready supply of grafting material–say for people who have burn injuries and need new skin.
You might also be able to produce albumen, which is a protein found in human blood. And what about bones, tendons, ligaments? There might be more uses down the road.
Y: And all "human-silkworm"!
蠶與植皮
Don: 從生物學(xué)上來(lái)說(shuō)，對(duì)物種基因的改造可謂是一件相對(duì)來(lái)說(shuō)比較好的事情。通過(guò)改變物種的基因構(gòu)造，人類可促使某些動(dòng)物或是植物產(chǎn)生出對(duì)人類有用的東西來(lái)。
Ya?l: 照我說(shuō)，這應(yīng)該已經(jīng)是上百年的事情了吧!比如說(shuō)，我們要喝牛奶，我們還會(huì)用棉花來(lái)做衣服。
D: 相當(dāng)正確，我們還用絲。
Y: 嗯，絲是由蠶吐出的。
D: 但是，基因改造完全又是另外一回事了。比如說(shuō)，在廣島大學(xué)的一項(xiàng)研究就說(shuō)明，我們可以通過(guò)對(duì)蠶的基因改造獲得一種人體所需的膠原質(zhì)。蠶在吐絲時(shí)會(huì)產(chǎn)生這種物質(zhì)。
Y: 太酷了!什么是膠原質(zhì)呢?
D: 膠原質(zhì)就是一種蛋白質(zhì)。膠原質(zhì)正好是組成人體皮膚、肌腱、韌帶甚至是骨骼的結(jié)構(gòu)蛋白，因而，膠原質(zhì)是相當(dāng)重要的。
Y: OK!那人類可以用這種膠原質(zhì)來(lái)做什么呢?
D: 當(dāng)然有許多了，其中之一就是用這種膠原質(zhì)來(lái)進(jìn)行皮膚移植。蠶一年可吐絲六萬(wàn)噸，因而如果含有膠原質(zhì)的絲產(chǎn)量能有所保障，對(duì)那些有燒傷在身或是需要植入新皮的人來(lái)說(shuō)，這的確是比較便宜的理想植皮材料。
植入后，人體還可能能夠產(chǎn)生人體血液中常見的蛋白質(zhì)——血清蛋白。除此之外，對(duì)骨骼、肌腱和韌帶又有什么作用呢?相信隨著日后研究的深入，人們能挖掘出它更多的用處。
Y: 到處都是“蠶人”!
