60秒科学:消化寿司的酵母素

Traditional Sushi Eaters Have Specialized¹ Gut² Bacteria

If you want to shell a walnut³, it helps to have a nutcracker. And if you want to digest seaweed, it helps to have the right enzymes⁵. Now, a study in the journal Nature shows that Japanese people—but not North Americans—have what it takes to eat their sushi, and digest it, too. [Jan-Hendrik Hehemann et al, The scientists were studying a particular marine⁶ bacterium⁷, which makes enzymes that break down the kind of seaweed used to wrap sushi. In searching the public databases, they discovered, to their surprise, that the enzymes was not just confined to ocean organisms. They also turned up in bacteria that live in the human gut.

Our intestines⁸ are teeming⁹ with trillions of bacteria from hundreds of different species. By sequencing the genomes of the microbial tenants¹⁰ from 30 volunteers, the scientists found that the Japanese harbor bugs¹¹ with seaweed-eating enzymes. Not so the North Americans.

The enzymes were most likely gifts from a marine microbe, eaten along with some seaweed a long time ago. The marine microbe happened to transfer some of its enzyme⁴ genes¹² to gut microbes. And with seaweed a staple¹³ in the Japanese diet, the genes stuck around. So it was a good bargain between man and microbe. Not a raw deal.

—Karen Hopkin
 

1 specialized   

adj.专门的，专业化的

参考例句：

• There are many specialized agencies in the United Nations.联合国有许多专门机构。
• These tools are very specialized.这些是专用工具。

2 gut   

n.[pl.]胆量；内脏；adj.本能的；vt.取出内脏

参考例句：

• It is not always necessary to gut the fish prior to freezing.冷冻鱼之前并不总是需要先把内脏掏空。
• My immediate gut feeling was to refuse.我本能的直接反应是拒绝。

3 walnut   

n.胡桃，胡桃木，胡桃色，茶色

参考例句：

• Walnut is a local specialty here.核桃是此地的土特产。
• The stool comes in several sizes in walnut or mahogany.凳子有几种尺寸，材质分胡桃木和红木两种。

4 enzyme   

n.酵素，酶

参考例句：

• Above a certain temperature,the enzyme molecule will become unfolded.超过一定温度，酶分子将会展开。
• An enzyme that dissolves the fibrin of blood clots.能溶解血凝块中的纤维的酶。

5 enzymes   

n. 酶，酵素

参考例句：

• It was said that washing powders containing enzymes remove stains more efficiently. 据说加酶洗衣粉除污更有效。
• Among the enzymes which are particularly effective are pepsin, papain. 在酶当中特别有效的是胃朊酶、木瓜酶。

6 marine   

adj.海的；海生的；航海的；海事的；n.水兵

参考例句：

• Marine creatures are those which live in the sea. 海洋生物是生存在海里的生物。
• When the war broke out,he volunteered for the Marine Corps.战争爆发时，他自愿参加了海军陆战队。

7 bacterium   

n.(pl.)bacteria 细菌

参考例句：

• The bacterium possibly goes in the human body by the mouth.细菌可能通过口进入人体。
• A bacterium is identified as the cause for his duodenal ulcer.一种细菌被断定为造成他十二指肠溃疡的根源。

8 intestines   

n.肠( intestine的名词复数 )

参考例句：

• Perhaps the most serious problems occur in the stomach and intestines. 最严重的问题或许出现在胃和肠里。 来自辞典例句
• The traps of carnivorous plants function a little like the stomachs and small intestines of animals. 食肉植物的捕蝇器起着动物的胃和小肠的作用。 来自辞典例句

9 teeming   

adj.丰富的v.充满( teem的现在分词 )；到处都是；（指水、雨等）暴降；倾注

参考例句：

• The rain was teeming down. 大雨倾盆而下。
• the teeming streets of the city 熙熙攘攘的城市街道

10 tenants   

n.房客( tenant的名词复数 )；佃户；占用者；占有者

参考例句：

• A number of tenants have been evicted for not paying the rent. 许多房客因不付房租被赶了出来。
• Tenants are jointly and severally liable for payment of the rent. 租金由承租人共同且分别承担。

11 bugs   

adj.疯狂的，发疯的n.窃听器( bug的名词复数 )；病菌；虫子；[计算机]（制作软件程序所产生的意料不到的）错误

参考例句：

• All programs have bugs and need endless refinement. 所有的程序都有漏洞，都需要不断改进。 来自《简明英汉词典》
• The sacks of rice were swarming with bugs. 一袋袋的米里长满了虫子。 来自《简明英汉词典》

12 genes   

n.基因( gene的名词复数 )

参考例句：

• You have good genes from your parents, so you should live a long time. 你从父母那儿获得优良的基因，所以能够活得很长。 来自《简明英汉词典》
• Differences will help to reveal the functions of the genes. 它们间的差异将会帮助我们揭开基因多种功能。 来自英汉非文学 - 生命科学 - 生物技术的世纪

13 staple   

n.主要产物，常用品，主要要素，原料，订书钉，钩环；adj.主要的，重要的；vt.分类

参考例句：

• Tea is the staple crop here.本地产品以茶叶为大宗。
• Potatoes are the staple of their diet.土豆是他们的主要食品。