VOA慢速英语 2007 0626a

This is the VOA Special English Agriculture Report.

Someday, rice plants might not only provide food but also a way to prevent cholera¹ and other diseases.

Cholera is a bacterial² infection of the intestines³. Today it is found mostly in Africa, Asia and Latin America. Current vaccines⁵ to protect against cholera must be kept in cold storage. The need for refrigeration limits use in poor countries.

But research in Japan may lead to rice plants that contain a cholera vaccine⁴ that does not need to be kept cold. So far, the research has been carried out only on mice. The Proceedings⁶ of the National Academy of Sciences in the United States published the study earlier this month.

Hiroshi Kiyono of the University of Tokyo and his team experimented with genetic⁷ material from the bacterium⁸ responsible for cholera. They placed it into the Kitaake rice plant.

Mice ate the genetically⁹ changed rice seeds as a powder. The report says the vaccine was not destroyed by stomach acid; instead, the animals developed antibodies against the cholera toxin¹⁰. The scientists say the vaccine remained active even after being stored at room temperature for more than a year and a half.

People would take the vaccine as a drug that contains the powder.

Cholera is usually spread through water or food, in places where conditions are dirty and drinking water supplies are unsafe. Cholera infections are often mild. But some people develop severe cases. The World Health Organization says half of them will die if they are not treated.

The researchers say the experimental cholera vaccine produced reactions in the immune system and in areas of mucosal tissue. Mucosal surfaces include the mouth, nose and reproductive organs. Cholera as well as viruses like those that cause influenza¹¹ and AIDS infect these areas.

The scientists have great hopes for rice-based vaccines as a way to protect large populations against mucosal infections. There would be no need for injection, since the vaccine would be taken by mouth.

Yet scientists have tried for some time to make plant-based vaccines. Researchers in the United States have developed one for Newcastle disease in chickens, but so far there are no products for humans. At the same time, scientists have to deal with concerns about genetically engineered plants accidentally mixing with food crops.

And that's the VOA Special English Agriculture Report, written by Jerilyn Watson.

1 cholera   

n.霍乱

参考例句：

• The cholera outbreak has been contained.霍乱的发生已被控制住了。
• Cholera spread like wildfire through the camps.霍乱在营地里迅速传播。

2 bacterial   

a.细菌的

参考例句：

• Bacterial reproduction is accelerated in weightless space. 在失重的空间，细菌繁殖加快了。
• Brain lesions can be caused by bacterial infections. 大脑损伤可能由细菌感染引起。

3 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

4 vaccine   

n.牛痘苗，疫苗；adj.牛痘的，疫苗的

参考例句：

• The polio vaccine has saved millions of lives.脊髓灰质炎疫苗挽救了数以百万计的生命。
• She takes a vaccine against influenza every fall.她每年秋季接种流感疫苗。

5 vaccines   

疫苗，痘苗( vaccine的名词复数 )

参考例句：

• His team are at the forefront of scientific research into vaccines. 他的小组处于疫苗科研的最前沿。
• The vaccines were kept cool in refrigerators. 疫苗放在冰箱中冷藏。

6 proceedings   

n.进程，过程，议程；诉讼(程序)；公报

参考例句：

• He was released on bail pending committal proceedings. 他交保获释正在候审。
• to initiate legal proceedings against sb 对某人提起诉讼

7 genetic   

adj.遗传的，遗传学的

参考例句：

• It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
• Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。

8 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。

9 genetically   

adv.遗传上

参考例句：

• All the bees in the colony are genetically related. 同一群体的蜜蜂都有亲缘关系。
• Genetically modified foods have already arrived on American dinner tables. 经基因改造加工过的食物已端上了美国人的餐桌。 来自英汉非文学 - 生命科学 - 基因与食物

10 toxin   

n.毒素，毒质

参考例句：

• Experts have linked this condition to a build-up of toxins in the body.专家已把这一病症与体内毒素的积累联系起来。
• Tests showed increased levels of toxin in shellfish.检验表明水生有壳动物的毒素水平提高了。

11 influenza   

n.流行性感冒，流感

参考例句：

• They took steps to prevent the spread of influenza.他们采取措施
• Influenza is an infectious disease.流感是一种传染病。