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  • To us humans, aging seems inevitable - probably because no human has ever not aged. But getting

    對人類而言,老化似乎是必然的- 或許是因為沒有人是不會老的 。但是

  • older isn’t as universal a fact of life as we might think.


  • Take the naked mole rat. Unlike their less-naked brethren, they don’t appear to age after

    以裸鼴鼠為例子。 跟牠們有毛的同類們不一樣,牠們成年後不會隨著

  • reaching adulthood - years pass, but the rats don’t get weaker, more susceptible to disease,


  • or least not any more wrinkly...and they keep on making as many babies as ever.


  • Surprisingly, they aren’t any more likely to die in old age than when theyre young


  • adults. It’s as if theyve found the fountain of youth, though perhaps not the fountain


  • of beauty. And naked mole rats aren’t alone in not aging: rockfish, lobsters, and bristlecone

    在不老方面,裸鼴鼠並不孤单 石斑魚,龍蝦, 及狐尾松

  • pines also seem to stay forever young...or at least forever middle-aged.


  • Were not exactly sure how these species do it, but their anti-aging secret may have

    我們不太確定這些物種是怎麼辦到的, 但是牠們抗衰老的秘密可能

  • to do with their ability to rebuild the DNA caps on their chromosomes. These caps, called


  • telomeres, are one line of defense against aging in many species. That’s because cells


  • need to divide to replace old or dysfunctional cells, but each time they replicate, they

    為了取代舊的或無功能的細胞而分裂, 但每次細胞複製,

  • lose a little bit of DNA from the end of each chromosome. Normally that doesn’t matter,

    會從染色體失去一點DNA 。那通常不重要,

  • since these lost bits come from the telomere end caps that don’t encode important information.


  • But after many replications, the telomeres get trimmed so short that the cells can’t


  • afford to lose any more DNA, and they stop replicating.

    無法負荷失去更多DNA, 就停止複製。

  • Age-defying species like naked mole rats, however, pump out high levels of a telomere-rebuilding


  • enzyme that enables them to keep on replacing old and dysfunctional cells indefinitely.


  • A few kinds of human cells make this enzyme, but the vast majority don’t. And even if


  • we could trick the rest into producing it, then we’d have another problem: more replications


  • means more chances for mutations that could turn a cell cancerous unlimited replication


  • increases a cell’s chances of becoming cancerous. Naked mole rats don’t care because they

    增加细胞變成癌細胞的機會。 裸鼴鼠不在乎,因為他們

  • seem to be immune to cancer; but we humans certainly aren’t.

    似乎對癌症免疫; 但我們人類肯定不是。

  • However, as amazing as naked mole rats are, they can only pause their agingthe tiny

    然而,就算裸鼴鼠如此令人驚歎,他們也只能暫停老化- 小小的

  • jellyfish Turritopsis dohrnii can age in reverse. Like butterflies, Turritopsis morph through


  • multiple stages during their life cycle. But unlike butterflies, if Turritopsis get wounded


  • or if times get tough, they can morph backwards, reverting to their immature polyp form until


  • conditions improve. Theyre like, real life phoenixes.


  • However if humans could somehow imitate Turritopsistrick, it might not give us the kind of eternal


  • youth we’d be looking forfor one thing, melting into an amorphous blob where our cells


  • are reorganized and reprogrammed with new functions would not only be a mess; it would


  • likely turn our brain cells into skin or muscle cells - and vice versa - erasing our memories

    那將會把我們的腦細胞變成皮膚或肌肉細胞- 反之亦然- 刪除我們的記憶

  • and our sense of self. And no matter what, eternal youth wouldn’t


  • make us invincible - in fact, the longer a creature lives, the more time it has to get

    使我們立於不敗之地- 事實上,生物活得愈久,牠就必須經歷更久的

  • chomped, starved, or smooshed. So eventually, every naked mole rat, pine tree, and jellyfish


  • will ultimately meet its end - because it’s possible to be immune to aging, but not to death.


To us humans, aging seems inevitable - probably because no human has ever not aged. But getting

對人類而言,老化似乎是必然的- 或許是因為沒有人是不會老的 。但是

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B2 中高級 中文 美國腔 細胞 水母 老化 燈塔 端粒 衰老

我們必須變老和死嗎? (Do We Have to Get Old and Die?)

  • 20748 783
    Charlene Tai 發佈於 2015 年 07 月 20 日