"长生不老"未来或成为现实?

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Today, Tony from the Vientiane International School in Laos asks the scientists about how long we - or our descendants - might live.

Tony: Is it possible for humans to live for 200 years?

EarthSky spoke to an MIT professor of biology who studies the genetic sequence that controls aging. Lenny Guarente said he's skeptical about humans living as long as 200 years. But, he said, new research could help extend our lifespan.

Lenny Guarente: In mammals, which includes us, what we think is the case, is that calorie restriction - a low calorie diet - triggers anti-aging genes better called sirtuins. And that enables us to forestall diseases of aging so we can stay healthier, longer, and perhaps to actually live longer.

Guarente doesn't believe that science could stop aging altogether.

Lenny Guarente: There're just too many things that go wrong in aging, that it would be almost impossible to fix them all at the same time so that you achieve immortality. But I think you can do, as you can achieve something that's better than what we have now.

He said life expectancy could increase anywhere from 10 to 30 years in the not too distant future.

Our thanks today to the Monsanto Fund, bridging the gap between the needs of people around the world and their resources.

I am Joel Block from E&S, a clear voice for science. We are at E&S. org.

[背景知识]

    1986年，当伦纳德·瓜伦特第一个提出通过限制卡路里的摄取来研究生物学的衰老时，这个主意听上去荒唐可笑。然而在过去十年中，研究人员主要了解为什么突然降低卡路里的摄取能激发一种名为SIR2的基因的活性并能延长简单生物体的寿命，而且取得了很大进展。

    瓜伦特和一位名叫戴维·辛克莱的哈佛大学研究者都是这方面的顶尖专家，他们主要研究名为“sirtuins”的抗衰老酶，这是SIR2或哺乳动物身上的与SIR2类似的SIRT1所产生的蛋白家族。瓜伦特的实验已经搞清楚了SIR2背后的很多基本分子过程。例如一种名为NADH的天然化学物质可以抑制“sirtuins”发挥作用；他们已经确认NADH含量较低的酵母存活的时间更长。辛克莱发现白藜芦醇与限制卡路里摄取有关联。研究表明，酵母在大剂量白藜芦醇的作用下能延长寿命70％。