趣味双语当前位置:英语 >> 字斟句酌 >> 双语阅读 >> 趣味双语


来源:天星 更新日期:2009-10-10 点击:

The 2009 Nobel Prize in medicine has been awarded to Elizabeth Blackburn, Carol Greider and Jack Szostak for the discovery of how chromosomes are protected by telomeres and the enzyme telomerase.

Australian-born Elizabeth Blackburn, British-born Jack Szostak and Carol Greider won the prize of 10 million Swedish crowns ($1.42 million).

The scientists have solved a major problem in biology: how the chromosomes can be copied in a complete way during cell divisions and how they are protected against degradation. The Nobel Laureates have shown that the solution is to be found in the ends of the chromosomes the telomeres - and in an enzyme that forms them - telomerase.

The long, threadlike DNA molecules that carry our genes are packed into chromosomes, the telomeres being the caps on their ends. Elizabeth Blackburn and Jack Szostak discovered that a unique DNA sequence in the telomeres protects the chromosomes from degradation. Carol Greider and Blackburn identified telomerase, the enzyme that makes telomere DNA. These discoveries explained how the ends of the chromosomes are protected by the telomeres and that they are built by telomerase.

If the telomeres are shortened, cells age. Conversely, if telomerase activity is high, telomere length is maintained, and cellular senescence is delayed. This is the case in cancer cells, which can be considered to have eternal life. Certain inherited diseases, in contrast, are characterized by a defective telomerase, resulting in damaged cells. The award of the Nobel Prize recognizes the discovery of a fundamental mechanism in the cell, a discovery that has stimulated the development of new therapeutic strategies.

In conclusion, the discoveries by Blackburn, Greider and Szostak have added a new dimension to our understanding of the cell, shed light on disease mechanisms, and stimulated the development of potential new therapies.

Medicine is traditionally the first of the Nobel prizes awarded each year. The prizes for achievement in science, literature and peace were first awarded in 1901 accordance with the will of dynamite inventor and businessman Alfred Nobel.

Q. What are telomeres and telomerase?

A. Telomeres are the protective caps at the ends of chromosomes in cells. Chromosomes carry the genetic information. Telomeres are buffers. They are like the tips of shoelaces. If you lose the tips, the ends start fraying.

Telomerase is an enzyme. In cells, it restores the length of the telomeres when they get worn. As the ends of the chromosomes wear down, the telomerase comes in and builds them back up.

In humans, the thing is that as we mature, our telomeres slowly wear down. So the question has always been: did that matter? Well, more and more, it seems like it matters.

Q. Is there a link between telomere length and stress?

A. In my lab, we’re finding that psychological stress actually ages cells, which can be seen when you measure the wearing down of the tips of the chromosomes, those telomeres.

A few years ago, Dr. Elissa Epel, a psychologist who studies chronic stress, came to see me. She asked, ‘Does stress have any effect on cell aging?’ There’s always been this observation that people under great stress appear to be care-worn. They look haggard, right?

So Elissa designed this study where we looked at two groups of mothers. One had normal, healthy children. The other group had a child with a chronic illness. Physiological and psychological measurements were done on everyone. With the stressed group, we found that the longer the mothers had been caring for their chronically ill child, the less their telomerase and the shorter their telomeres.

This was the first time you could clearly see cause and effect from a nongenetic influence. Genes play a role in telomerase levels, but this was not genes. This was something impacting the body that came from the outside and affecting its ability to repair itself. By the way, we found similar effects in women who were primary caregivers for partners with dementia.

Q. Is this scientific proof of the mind-body connection?

A. It’s a proof. There have been others. Researchers have found that the brain definitely sends nerves directly to organs of the immune system and not just to the heart and the lower gut. In that way, too, the brain is influencing the body.

One of the things that came out of our study of these mothers is a link between low telomerase and stress-related diseases. We looked at the measures for cardiovascular disease — bad lipid profiles, obesity, all that stuff. The women with those had low telomerase.

We also looked at low telomeres and cancer. We wondered if a cell with worn down chromosome tips might divide in some abnormal way. Our findings have yet to be published, so I can’t tell you much here, but we think we’re onto something.

2009年诺贝尔生理学或医学奖揭晓:共有三名获奖者,分别是:伊丽莎白 H. 布莱克本(Elizabeth H. Blackburn)、卡罗尔·W. 葛莱德尔(Carol W. Greider)和杰克 W. 卓斯塔克(Jack W. Szostak),他们的功绩是发现了染色体端粒及端粒酶对染色体的保护机制。