11-11 为何鳄鱼不会受感染？（在线收听）

Why Crocodiles Not Get Infections?

Jill Fullerton Smith, a television producer, discovered why crocodiles can heal themselves in bacteria filled water.

“In television we have to make films that entertain people. People are very interested in anything with big teeth. And so I volunteered that I would look for a film with big teeth.”

Jill believes that the crocodile is one of the scariest beasts you are ever going to encounter because they are “still, calm and so quiet. You know that if you go anywhere near them, you are dead.”

Jill bumped into¹ a young zoologist² called Adam Briton who absolutely loves crocodiles. One of the things that interested him about crocodiles was that as part of their natural behaviour they fight other crocodiles and regularly lose limbs. What amazed him was that crocodiles sit in dirty, bacteria filled water and yet they never seemed to get infections their limbs heal quickly.

Jill says it took her three months to realize that this was a fantastic question. Why is it that a crocodile could heal in the same bacteria filled water and that if we had that wound, we would die?

“There had to be something amazing in the crocodile’s immune³ system and we very quickly found out that there is a little string of peptides⁴ that were only discovered very recently in the last eight or nine years and they are a powerful mechanism for fighting bacteria”.

Jill set out to make a film about the collecting of the samples. It was a long wait to find out if there was this peptide in the crocodile’s blood.

“I think we waited five months for the results to come through and we got the call to say that they’d found it.”

Rozina Ali, a plastic surgeon, explains that antimicrobial⁵ peptides are small proteins lots of amino⁶ acids put together in various configurations⁷. The interesting thing about them to medics is that they are antimicrobial which means that they work against microbes and microbes means bacteria, fungi⁸ and viruses.

Jill says, “As far as we know so far there aren’t any organisms which have any resistance to these antimicrobial peptides. It’s something very important in the future in medicine.”

She believes that some scientific discoveries are just luck, serendipity⁹. “People happen to find something but I don’t think it’s pure luck. You ask the question why do crocodiles not get infections and then you set out to answer the question. And what it takes is not the initial idea but the actual perseverance and stamina¹⁰ to see it through and I think that’s what makes a scientist.”

注释：

1. bump into [口]偶然遇见，碰见

2. zoologist [zEu5ClEdVist] n. 动物学家

3. immune [i5mju:n] a. [生]免疫的

4. peptide [5peptaid] n. [生化]肽，缩氨酸

5. antimicrobial [7Antimai5krEubiEl] a. 抗微生物的，抗菌的

6. amino [5AminEu] a. [化]氨基的

7. configuration [kEn7fi^ju5reiFEn] n. 配置，布局，结构，构造

8. fungus [5fQN^Es] （[复 ] -gi [-gai]或 –guses） n. [植]真菌

9. serendipity [7serEn5dipiti] n. 侥幸发现的东西，意外的发现

10. stamina [5stAminE] n. 精力，耐力，持久力

为何鳄鱼不会受感染？

电视制作人吉尔·富勒顿－史密斯发现了鳄鱼的伤口为什么能在充满了细菌的水里得以自愈。

　　“在电视中，我们必须制作出能使人们开心的片子。人们对凡有着大牙齿的动物都非常感兴趣。所以我自告奋勇去寻找有大牙齿的电视片题材。”

　　吉尔相信鳄鱼是你将遇到的最为可怕的动物之一，因为它们“一动不动、平静如水，但是你知道如果你走近它们，你就死定了。”

　　吉尔碰到了一位名叫亚当·布里顿的年轻动物学家，他极其喜爱鳄鱼。鳄鱼令他感兴趣的一点是，鳄鱼出于本性相互厮杀，并经常残损肢体。令他惊讶的是，鳄鱼生活在肮脏、充满细菌的水中，但好像从来不会感染，它们的肢体很快便痊愈了。

　　吉尔说她花了3个月的时间才意识到这是一个奇妙的问题。为什么一条鳄鱼可以在充满细菌的水中自愈，而我们如果在这种水中受伤，就会丧命？

　　“鳄鱼的免疫系统中一定存在着不同寻常之处。我们很快地发现了一小串缩氨酸。这是在最近8、9年才发现的一种具有强大的抗菌能力的物质。”

　　吉尔开始拍摄搜集这些样品的电视片。发现鳄鱼血液中是否存在这种缩氨酸是一次漫长的等待。

　　“我想我们等了5个月才获得了结果。我们接到电话说他们发现了缩氨酸物质。”

　　整形外科医生罗津娜·阿里解释说，抗菌的缩氨酸是一种小的蛋白质——许多氨基酸以不同的结构组合在一起。令医生感兴趣的是它们具有抗微生物性，也就是说它们能够攻击微生物，而微生物就是细菌，真菌和病毒。

　　吉尔说：“据我们所知，到目前为止还没有任何生物体会排斥这些抗微生物的缩氨酸。这对于未来的医学很重要。”

吉尔认为有些科学发现靠的就是运气，所谓“意外发现的珍宝”。“人们碰巧发现某种东西，但是我认为这不纯属运气。你提出这样一个问题——鳄鱼为什么不会受感染？然后你开始回答这个问题。要获得成功，靠的不是最初的想法，而是坚持到底的耐心和毅力。我想这样才能造就一名科学家。”