VOA标准英语2011--Microbe Could Help Battle Malaria

Microbe Could Help Battle Malaria¹

Researchers have discovered a bacterium² in the gut³ of the Anopheles mosquito which may someday be used to destroy and, therefore, prevent the spread of the disease-causing parasite⁴.
The World Health Organization estimates 800,000 people die of malaria each year. The parasite that causes the disease is transmitted by the Anopheles mosquito. After the mosquito feeds on the blood of an infected individual, the parasite matures into an infectious stage in the insect's gut. From there, the parasite, known as Plasmodium falciparum, takes up residence in the mosquito's salivary⁵ glands⁶ so it can infect the next person that's bitten.
Researchers at Johns Hopkins School of Public Health in Baltimore, Maryland found the bacterium in the gut of the Anopheles mosquito among hundreds of so-called microbial flora⁷ that live harmlessly in the stomach of a group of Anopheles mosquitoes collected in an area of southern Zambia where malaria is rampant⁸.
The microbe, which was in the guts⁹ of a small percentage of the mosquitoes, protected those insects against infection with the parasite.
Lead researcher George Dimopoulos says the protection seems to be a side-effect of the bacterium's normal bodily function, adding that scientists would like to figure out a way to use the microbe as a weapon against malaria.
"Our study has shown that this bacterium produces free radicals¹⁰, molecules¹¹ that contain oxygen and that can cause damage to cells. So, we believe that's how this bacterium is killing¹² the malaria parasite in the mosquito gut. But we need to understand that mechanism¹³ in greater detail."
To demonstrate the beneficial effect, the researchers used antibiotics¹⁴ to kill the bacterium in mosquitoes that contained it, and were then able to infect those mosquitoes more easily with the Plasmodium parasite.
They also introduced the bacterium into the guts of mosquitoes that didn't have it. When they fed this group infected blood, the parasite was destroyed in nearly all of the insects.
Dimopoulos says researchers' goal now is to figure out a way to introduce the microbe into large populations of Anopheles mosquitoes - perhaps through bait laced with their favorite snack.
"Mosquitoes need to feed on sugar every day. And one can potentially expose mosquitoes in the field to these bacteria through sugar bait."
The researchers noted¹⁵ that mosquitoes with the bacterium in their guts die sooner than those without it - when both groups are infected with the parasite. Since the malaria parasite lives in mosquitoes for about two weeks before maturing to an infectious stage, Dimopoulos says it's good news that the stomach bacterium seems to shorten the insect's lifespan, before it could potentially transmit the parasite to humans.

1 malaria   

n.疟疾

参考例句：

• He had frequent attacks of malaria.他常患疟疾。
• Malaria is a kind of serious malady.疟疾是一种严重的疾病。

2 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。

3 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。

4 parasite   

n.寄生虫；寄生菌；食客

参考例句：

• The lazy man was a parasite on his family.那懒汉是家里的寄生虫。
• I don't want to be a parasite.I must earn my own way in life.我不想做寄生虫，我要自己养活自己。

5 salivary   

adj. 唾液的

参考例句：

• Small doses depress salivary and bronchial secretion and sweating. 小剂量可抑制唾液分泌、支气管分泌及出汗。
• The five pairs of salivary glands open into the mouth. 有五对唾液腺通向口腔。

6 glands   

n.腺( gland的名词复数 )

参考例句：

• a snake's poison glands 蛇的毒腺
• the sebaceous glands in the skin 皮脂腺

7 flora   

n.(某一地区的)植物群

参考例句：

• The subtropical island has a remarkably rich native flora.这个亚热带岛屿有相当丰富的乡土植物种类。
• All flora need water and light.一切草木都需要水和阳光。

8 rampant   

adj.(植物)蔓生的；狂暴的，无约束的

参考例句：

• Sickness was rampant in the area.该地区疾病蔓延。
• You cannot allow children to rampant through the museum.你不能任由小孩子在博物馆里乱跑。

9 guts   

v.狼吞虎咽，贪婪地吃，飞碟游戏（比赛双方每组5人，相距15码，互相掷接飞碟）；毁坏（建筑物等）的内部( gut的第三人称单数 )；取出…的内脏n.勇气( gut的名词复数 )；内脏；消化道的下段；肠

参考例句：

• I'll only cook fish if the guts have been removed. 鱼若已收拾干净，我只需烧一下即可。
• Barbara hasn't got the guts to leave her mother. 巴巴拉没有勇气离开她妈妈。 来自《简明英汉词典》

10 radicals   

n.激进分子( radical的名词复数 )；根基；基本原理；[数学]根数

参考例句：

• Some militant leaders want to merge with white radicals. 一些好斗的领导人要和白人中的激进派联合。 来自《简明英汉词典》
• The worry is that the radicals will grow more intransigent. 现在人们担忧激进分子会变得更加不妥协。 来自辞典例句

11 molecules   

分子( molecule的名词复数 )

参考例句：

• The structure of molecules can be seen under an electron microscope. 分子的结构可在电子显微镜下观察到。
• Inside the reactor the large molecules are cracked into smaller molecules. 在反应堆里，大分子裂变为小分子。

12 killing   

n.巨额利润；突然赚大钱，发大财

参考例句：

• Investors are set to make a killing from the sell-off.投资者准备清仓以便大赚一笔。
• Last week my brother made a killing on Wall Street.上个周我兄弟在华尔街赚了一大笔。

13 mechanism   

n.机械装置；机构，结构

参考例句：

• The bones and muscles are parts of the mechanism of the body.骨骼和肌肉是人体的组成部件。
• The mechanism of the machine is very complicated.这台机器的结构是非常复杂的。

14 antibiotics   

n.（用作复数）抗生素；（用作单数）抗生物质的研究；抗生素，抗菌素( antibiotic的名词复数 )

参考例句：

• the discovery of antibiotics in the 20th century 20世纪抗生素的发现
• The doctor gave me a prescription for antibiotics. 医生给我开了抗生素。

15 noted   

adj.著名的，知名的

参考例句：

• The local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
• Jim is noted for arriving late for work.吉姆上班迟到出了名。