Scientists search for new ways to treat infection

VOA 2012-10-24 13:30

分享到

 

Get Flash Player

Download

This is SCIENCE IN THE NEWS, in VOA Special English. I’m Christopher Cruise.

And I’m Jim Tedder. Today, we report on the search for new ways to treat infections. We tell how researchers used DNA, deoxyribonucleic acid, to study the roots of the English language. And we tell about an experiment that shows you can learn while you sleep.

In nineteen twenty-eight, a British scientist made a chance observation. He found that some mold had grown in bacteria in a culture plate in his laboratory. Molds can do that. But this mold that had somehow gotten into the plate had the ability to kill the bacteria around it.

The scientist, Alexander Fleming, found that the mold was a member of a common group known as Penicillium. Fleming and two other scientists, Ernst Boris Chain and Howard Walter Florey, went on to win the Nobel Prize in nineteen forty-five. They were honored "for the discovery of penicillin and its curative effect in various infectious diseases."

Other powerful antibiotics have been discovered since penicillin. But many antibiotics have become less effective as the germs they are designed to kill develop resistance.

​​So scientists are searching for new ways to treat infections. Recently, researchers in Australia said they made an important discovery. Scientists at Monash University in Melbourne believe an antibacterial viral protein called PlyC could be used as an alternative to antibiotics.

This protein was first identified as a possible treatment for infections in nineteen twenty five. But the research ended following the discovery of antibiotics.

Now, scientists have spent six years studying the structure of the protein. They have found how it kills the bacteria that cause sore throats, pneumonia and streptococcal toxic shock syndrome.

Australian researchers worked with scientists at the Rockefeller University in New York and the University of Maryland. Their findings appeared in the Proceedings of the National Academy of Sciences.

Sheena McGowan from Monash University describes the protein as a powerful bacterial killing machine. She says it looks like a flying saucer carrying a pair of warheads. It connects to the surface of the bacterium and then cuts through the outside to destroy it.

Dr. McGowan says it could be highly valuable when conditions like pneumonia do not respond to traditional treatments.

"There's antibiotics at the moment for those particular types of diseases. We sort of see that there's a bit of resistance being built up in the bacterial community almost, and some of our antibiotics aren't quite as effective as they used to be. So this kind of ground route, basic research needs to be done quite early so that we have some time to develop them as safe human therapeutic over the timeframe when the antibiotics can keep working."

The researchers have been studying PlyC's atomic structure in hopes of developing a drug. They say they have had success in treating streptococcal infections in mice. But an effective human treatment in the form of a pill or nasal spray may be at least ten years away.

One of the jobs of an evolutionary biologist is to study the genetic material of viruses. Studying the DNA can show where a virus came from, how it changed over time and how it is related to other viruses.

Now, scientists have borrowed this idea for a completely different purpose: to study the roots of the first Indo-European language. Indo-European is a family of several hundred related languages including English, French, Russian and Persian.

Indo-European is one of the largest language families in the world. It covers an area from Iceland in the west to Sri Lanka in the east. One theory says it developed six thousand years ago and was spread by a horse-riding people in the Russian Steppes north of the Caspian Sea. Another theory says the common ancestor of Indo-European was first spoken in what is now Turkey. This theory says it began eight thousand to nine thousand five hundred years ago and spread with agriculture.

The new study offers support for this second theory. Quentin Atkinson, an evolutionary psychologist at the University of Auckland in New Zealand, led the study. He says his team worked in much the same way that evolutionary biologists do to identify the origin of virus outbreaks.

“They use the DNA to reconstruct the family tree of the viruses. But rather than looking at viruses, we were looking for languages. And rather than looking at DNA, we were looking at the words in the different languages.”

The researchers used a statistical method that evolutionary biologists use to show how different species are related on a family tree. They analyzed two hundred two cognates, or words with shared meanings and similar sounds. They studied them across one hundred three languages, including twenty that are no longer spoken.

Quentin Atkinson says examining the similarities and differences in these cognates helped establish family ties. For example, in English and other Germanic languages, the word for "water" sounds something like the English word "water" or "wasser" in German. But in the Romance languages that came from Latin, the word sounds a lot different, something like "agua" in Spanish or "acqua" in Italian.

Mr. Atkinson says that although some words are more closely related than others, they are tied together on branches of the Indo-European family tree.

“We know where the languages are. They are like the leaves of the tree, and we know how they are connected, and we trace back along those branches back through time and space to work out where the origin is.”

He argues that Indo-European started to expand across Europe with the spread of agriculture.

“We can see the spread in the archeological record. So the argument is that agricultural populations were able to increase their population density relative to hunter gatherer populations around them, and so they expanded out generation by generation.”

The study appeared in the journal Science. Quentin Atkinson says the method used to study the origins of the Indo-European language family could also be used with other language groups.

Last year, he published a report in Science exploring the earliest history of human language. He suggested that modern languages began in southwestern Africa. For that study, he borrowed an idea that comes not from evolutionary biologists but from scientists who study population genetics. They call it the "serial founder effect." It offers a scientific explanation for why there are fewer genetic differences in populations the farther away they live from Africa. Scientists say this decrease in diversity shows that modern humans originated on the continent.

Quentin Atkinson reported finding a similar effect in language. He based his study on the phonemes -- the basic speech sounds, like vowels and consonants -- in about five hundred different languages. He reported that languages in southwestern Africa had the most phonemes, while the numbers decreased with distance from the continent. Mr. Atkinson says his findings support the theory that modern humans expanded from Africa. Some other scientists, however, suggested that the results of his study were weak and failed to prove where language started.

Imagine you are walking down the street. As you pass a bakery, someone opens the door.

Ah…what a wonderful smell. Freshly baked bread, just out of the oven. You breathe deeply, letting that great smell fill your lungs. Life is good!

Now imagine that as you keep walking, you pass a fish market. A worker has just thrown a box full of rotting fish parts into a waste basket.

Oooh! Whew! The smell is so bad, you take only a short breath and hurry on your way.

Anat Arzi of the Weizmann Institute of Science in Israel imagined this kind of reaction recently when she performed sleep experiments in her laboratory. First, she made sure that her volunteers were in a deep sleep…no peeking …eyes tightly closed.

Then she opened a bottle of sweet smelling shampoo…and then…and this is important… played a soft musical note.

Then, she held something rotten under the volunteer’s nose …and played a different sound.

One of the best things about this kind of experiment is that it did not wake the volunteers. And when they were awakened, they had no memory of what had happened.

The next morning, after the people woke up, they thought the experiment was done. It was then that Anat Arzi played one of the sounds used while they were asleep and carefully measured their breathing. What she found was that the human brain, even while asleep, had learned to connect the smell with the sound.

This caused the patient to take a long, deep breath.

This caused a short intake of air.

So, what does all this mean? Ms. Arzi and her professor, Noam Sobel say it shows that we can learn while we are asleep. They may be the first scientists to use the sense of smell in this way as part of a sleep experiment. Their study was published in the journal Nature Neuroscience.

They hope that future experiments will show that we can learn much more difficult things while sleeping. Like chapter three in your calculus book, or how to write a new computer software program. Now that would be a sweet dream!​

相关阅读

Mobile phones could help efforts to end malaria

Visit to a medical museum

Nobel Prize in economics recognizes 'market designers'

Words and their stories: baseball terms

(来源:VOA 编辑:Julie)

 

分享到

中国日报网英语点津版权说明:凡注明来源为“中国日报网英语点津:XXX(署名)”的原创作品,除与中国日报网签署英语点津内容授权协议的网站外,其他任何网站或单位未经允许不得非法盗链、转载和使用,违者必究。如需使用,请与010-84883561联系;凡本网注明“来源:XXX(非英语点津)”的作品,均转载自其它媒体,目的在于传播更多信息,其他媒体如需转载,请与稿件来源方联系,如产生任何问题与本网无关;本网所发布的歌曲、电影片段,版权归原作者所有,仅供学习与研究,如果侵权,请提供版权证明,以便尽快删除。

中国日报网双语新闻

扫描左侧二维码

添加Chinadaily_Mobile
你想看的我们这儿都有!

中国日报双语手机报

点击左侧图标查看订阅方式

中国首份双语手机报
学英语看资讯一个都不能少!

关注和订阅

本文相关阅读
人气排行
热搜词
 
 
精华栏目
 

阅读

词汇

视听

翻译

口语

合作

 

关于我们 | 联系方式 | 招聘信息

Copyright by chinadaily.com.cn. All rights reserved. None of this material may be used for any commercial or public use. Reproduction in whole or in part without permission is prohibited. 版权声明:本网站所刊登的中国日报网英语点津内容,版权属中国日报网所有,未经协议授权,禁止下载使用。 欢迎愿意与本网站合作的单位或个人与我们联系。

电话:8610-84883645

传真:8610-84883500

Email: languagetips@chinadaily.com.cn