VOA英语2010年-Research Finds Possible New Way to Attack Sl

African sleeping sickness affects mostly rural people in 36 sub-Saharan countries. The World Health Organization says there are currently an estimated 30,000 cases. Left untreated, it is fatal.

 

Sleeping sickness is caused by a parasite¹ that is transmitted to humans by the tsetse fly. The parasite is a one-cell protozoa like ones you might have seen under a classroom microscope, floating around in fluid.

"But it turns out that, under the right conditions, they can actually transition to a multi-cellular form," says Kent Hill, a professor at the University of California, Los Angeles (UCLA) Department of Microbiology. "And in that form there's groups of cells that can sense their environment, that can communicate with one another, and that can engage in coordinate² activities."

Hill and his colleagues used an artificial material in the lab to simulate a surface like the tissue inside an infected person. They found that the parasites³ gathered together in groups on these lab surfaces.

"And that is when we discovered that they change from acting⁴ as individual organisms, where they'd come together as these little groups, and then the little groups would actually send out parasites to look for more parasites and make the group bigger."

For years, microbiologists knew about this sort of grouping behavior in bacteria, but it had never been observed before in microbes like the sleeping sickness parasite.

"So we're really, really excited about it because it was kind of a really new observation," Hill says. "It was something we weren't expecting. And it turns out that once we discovered it, if we look at other microbes and bacteria, we kind of felt that we were a little surprised we didn't see it before."

According to Hill, the discovery of this previously-unknown aspect of the parasite's lifecycle opens up new possibilities for disrupting that lifecycle to stop the disease.

For example, when they are grouped together, the individual parasites communicate with each other by exchanging proteins, which bind⁵ to receptors on the surface of the cell.

"And so what we've got now are proteins on the parasite that are accessible on live cells to small molecules⁶ - meaning like drugs - that you could add to live cells, and they interfere⁷ with behavior of the parasite. And so we hope that this will lead to more ability to develop drugs for targets that are accessible on the parasites."

Although this work is still very much in the early research stage, Hill says it's possible that if drugs can be developed to target the sleeping sickness parasite, the same general principle might also be used against the parasites that carry some other tropical diseases including malaria⁸ and leishmaniasis.

Hill of the UCLA Department of Microbiology presented his research at the annual meeting of the American Society for Cell Biology in Philadelphia.

1 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。

2 coordinate   

adj.同等的，协调的；n.同等者；vt.协作，协调

参考例句：

• You must coordinate what you said with what you did.你必须使你的言行一致。
• Maybe we can coordinate the relation of them.或许我们可以调和他们之间的关系。

3 parasites   

寄生物( parasite的名词复数 )； 靠他人为生的人； 诸虫

参考例句：

• These symptoms may be referable to virus infection rather than parasites. 这些症状也许是由病毒感染引起的，而与寄生虫无关。
• Kangaroos harbor a vast range of parasites. 袋鼠身上有各种各样的寄生虫。

4 acting   

n.演戏，行为，假装；adj.代理的，临时的，演出用的

参考例句：

• Ignore her,she's just acting.别理她，她只是假装的。
• During the seventies,her acting career was in eclipse.在七十年代，她的表演生涯黯然失色。

5 bind   

vt.捆，包扎；装订；约束；使凝固；vi.变硬

参考例句：

• I will let the waiter bind up the parcel for you.我让服务生帮你把包裹包起来。
• He wants a shirt that does not bind him.他要一件不使他觉得过紧的衬衫。

6 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。

7 interfere   

v.(in)干涉，干预；(with)妨碍，打扰

参考例句：

• If we interfere, it may do more harm than good.如果我们干预的话，可能弊多利少。
• When others interfere in the affair,it always makes troubles. 别人一卷入这一事件，棘手的事情就来了。

8 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。