最近，发表在英国《自然》杂志上的一项小鼠实验研究表明，一种对细胞自噬过程至关重要的蛋白质（beclin-1）发生突变后，会增加小鼠大脑和肌肉中的细胞自噬，可延长小鼠的健康期限和寿命。
自噬（autophagy）一词来源于希腊语的自我（auto-）和吃（-phagy），所以细胞自噬的意思就是“吃掉自己”。这一概念最早提出于20世纪60年代，但因当时研究这种现象困难重重，人们对其一直所知甚少。直到20世纪90年代早期，人们才了解了它的机制，并意识到它的重要性。此前的研究发现，自噬与蠕虫的衰老相关，而今，却是第一次将这种关系印证到了哺乳动物身上。
随着自噬研究的深入扩展，人们已认识到这不再是一种简单反应，许多生理现象的发生都与之有密切关系。同时，进行该实验的研究团队表示，这可能是哺乳动物增加细胞自噬、预防过早衰老、延长健康期限和寿命的一种有效机制。
本篇课程选自 The Economist Espresso APP
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New diet trend: autophagy and ageing
① Few would turn down the chance to live longer, and ideas range from starvation diets to blood transfusions from the young.
② A paper published in Nature this week looks at autophagy (Greek for "self-eating"), the process by which cells break down and recycle parts for re-use.
③ Researchers found that mice engineered to have higher levels of beclin-1, an autophagy-associated protein, lived about 10% longer than unmodified cousins.
④ They were healthier, too, suffering fewer cancers and less heart and kidney damage.
⑤ The finding joins mounting evidence that autophagy is important in hindering ageing, though the mechanism remains unclear.
⑥ (One theory is that it recycles worn-out cellular components whose operation generates highly reactive free radicals—chemicals that play havoc with all sorts of cellular processes.)
⑦ The protein in question might one day make a target for drug development.
⑧ However, as with all drugs, the treatment will be in the dose—too much autophagy is as bad as too little.
参考资料：
https://huanqiukexue.com/a/qianyan/shengwu__yixue/2015/1120/25791.html
▍生词好句
autophagy /ɔ:ˈtɒfədʒi/: n.（细胞的）自体吞噬
turn down: 拒绝
range from A to B: 从 A 到 B（内容很丰富、什么都有）
starvation diet: 饥饿疗法；饥饿式节食减肥
blood transfusion /ˌtransˈfjʊ:ʒ(ə)n/: 输血
look at: 探讨
engineered /ˌendʒɪˈnɪəd/: adj. 被基因工程改编的
beclin-1: 细胞分化、凋亡和自噬过程中起重要作用的多功能蛋白
autophagy-associated protein /ˈprəʊti:n/: 参与自噬的蛋白
unmodified /ʌnˈmɒdɪfʌɪd/: adj. 未被改编的；未被修改的
mounting /ˈmaʊntɪŋ/: adj. 越来越多的
join mounting evidence: 在逐渐增加的证据上又添了一笔
hinder ageing /ˈhɪndə/: 抗衰老
generate /ˈdʒenəreɪt/: vt. 制造；生成
free radical: 自由基；游离基
play havoc with /ˈhævək/: 对……有（不好的）影响
sth. in question: 正被讨论的……
make sth.: 成为……
in the dose /dəʊs/: 剂量问题
▍补充例句
1. range from A to B
我们的课程很多，从时尚到哲学，从文学到商务。
Our courses range from fashion to philosophy, and from literature to business.
2. look at
这部电影探讨了一些社会问题。
This movie looks at some social issues.
3. mounting
① 他们的债务越来越多。
They faced mounting debts.
② 要求他辞职的压力越来越大。
There was mounting pressure on him to resign.
4. play havoc with
下雨一直影响着体育比赛的进行。
Rain has continued to play havoc with sporting events.
5. make
有一天，你会成为优秀的科学家。
One day, you'll make a fabulous scientist.
6. in the dose
所有的化学物质都有毒性，但是它们都存在一个剂量问题。
Every chemical has toxicity, but it's all in the dose.