一起聽英語 168 轉(zhuǎn)基因牛

轉(zhuǎn)基因的東西越來越多，食用這些轉(zhuǎn)基因食品是否會對人體健康造成不利?

Jen: Hello and welcome to 6 Minute English from BBC Learning English. I'm Jen

and with me today is Neil.

Neil: Hello there.

Jen: Today’s story is all about allergies. If you have an allergy to something,

your body reacts to it in a negative way. Do you have any allergies, Neil?

Neil: I get hay fever in the summer; that happens when you have an allergy to

pollen from plants or trees.

Jen: And what happens when you get hay fever?

Neil: It’s horrible. I start sneezing, and my eyes become red and itchy, my nose

runs and I sometimes get a real headache.

Jen: That doesn’t sound very pleasant. Well, on today’s programme we’re

going to be taking a look at how genetically modified food might be able

to help people with allergies.

Neil: That’s quite a complicated topic!

Jen: It is, but I’m going to ease you in gently with a quiz question first, to get

you thinking! In what year was the first genetically modified food sold on

the market. Was it?

a) 1984

b) 1994

c) 2004

Neil: Well, as usual, I have no idea, so this is a guess, but I’ll say… 1984.

Jen: We’ll find out if you’re right at the end of the programme, but let’s get

back to our story about allergies.

Neil: Some allergies, like hay fever, can be described as mild. That means that

you might experience some unpleasant symptoms like itchy eyes,

sneezing or a rash.

Jen: Others, though, can be more severe, and can cause problems with

breathing, or even death.

Neil: Many people are allergic to a particular type of food, such as nuts or eggs,

for example.

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Jen: Very true, but did you know that cow’s milk can also cause problems?

Listen to the first part of this report from BBC correspondent James

Gallagher. How does cow’s milk affect some babies?

BBC correspondent James Gallagher:

Allergic reactions to cow’s milk are common in babies. Up to three percent treat it as

dangerous with their immune systems launching an attack on proteins found in cow's

milk, but never in their mother's breast milk.

Jen: Your body is protected by your immune system. That’s a series of cells

and tissues which stop you from catching diseases or infections.

Neil: These cells attack anything which they think is harming, or damaging the

body.

Jen: It’s quite common for babies to have allergic reactions to cow’s milk, so

their bodies are attacking it.

Neil: However, as we heard in the report, the babies’ bodies never attack

breast milk.

Jen: So, there must be something in the cow’s milk that babies’ bodies don’t

like. Listen to the second part of the report: what have scientists done to

cow’s milk?

BBC correspondent James Gallagher:

Now researchers in New Zealand have cut out one of the main culprits - the protein

beta-lactoglobulin. They added new genetic material to disrupt its manufacturing

process in a technique called RNA interference.

Jen: Scientists identified a protein in cow’s milk which causes allergic reactions.

Neil: In the report, this was called the culprit. The word culprit is often used to

describe the bad guy in a book or film – here, it’s used to describe the

dangerous protein.

Jen: The scientists have introduced a new genetic material to the cows to stop

this protein being made.

Neil: If you like, the cows have been genetically modified.

Jen: Their genes have been altered, or changed, so they don’t produce the

harmful protein in their milk.

Neil: It sounds pretty complicated, but if there is no harmful protein in the milk,

then babies shouldn’t have an allergic reaction. Now that’s good, isn’t it?

Jen: Well, not everyone thinks it’s a good thing. Here’s James Gallagher again:

BBC correspondent James Gallagher:

A study published in Proceedings of the National Academy of Sciences showed the GM

cow did not produce the protein in its milk. Other scientists said it was a spectacular

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study, while campaign groups have questioned the ethics of genetically modifying farm

animals.

Neil: So, some people think this scientific study is spectacular – in other

words, they think it’s amazing.

Jen: Very true, but we also heard in the report that some campaign groups

think that it’s unethical to genetically modify animals.

Neil: They think it’s morally wrong to interfere with, or change, nature.

Jen: Some people also worry about what effects genetic modification of

animals could have on our health.

Neil: That’s true, I suppose there could be side effects that people don’t yet

know about.

Jen: On the other hand, some people argue that genetic modification could be

used to produce super crops, and maybe, one day, help to stop world

hunger.

Neil: Who knows what type of foods will be available in the future?

Jen: We’ll have to wait to find out, but I can tell you about the first genetically

modified food which became available, but first, I asked you when it came

onto the market for the very first time. Was it:

a) 1984

b) 1994

c) 2004

Neil: And I said 1984.

Jen: Well, you were wrong! It was actually 1994. And it was a tomato. It was

genetically modified so that it would stay green for longer after it was

harvested.

Neil: So it had a longer shelf life.

Jen: Exactly! We’re coming to the end of the programme now, so there’s just

time to go over some of the vocabulary we’ve heard today.

Neil: The words and phrases were:

Allergy

Mild

Immune system

Culprits

Genetically modified

Spectacular

Unethical

Jen: Bye for now!