经济学人120:癌症与肥胖 恶性松弛

 　　Science and Technology Cancer and obesity¹ Malignant² flab

　　科技 癌症与肥胖 恶性松弛

　　At last, an understanding of how overeating causes cancer

　　吃得过多如何导致癌症

　　OVERWEIGHT women are more likely to develop breast cancer than lean ones.

　　超重的女人相比偏瘦的女人更容易得乳癌。

　　Why has been a mystery.

　　原因一直以来都是个迷。

　　But it is now less mysterious thanks to the work of Kevin Gardner, a researcher at America's National Cancer Institute in Bethesda, Maryland.

　　但由于马里兰州美国国家癌症协会研究院KG研究员为此做出的努力，现在并没有之前那么神秘了。

　　Dr Gardner and his colleagues have found that processing calories affects the activity of BRCA1, a gene³ that encodes a well-known tumour-suppression protein.

　　KG博士和他的同事们发现合成卡路里的过程会影响BRCA1基因的活性，该基因为一种著名的抗肿瘤蛋白质编码。

　　Mutations of this gene are strong predictors of breast and ovarian cancer—so strong that the gene's DNA⁵ sequence is the subject of litigation in America about whether natural gene sequences can be patented, and thus the market in tests for these mutations cornered.

　　BRCA1基因的突变是乳癌和卵巢癌的强烈预报器---如此强烈以至于在美国，常常就有关自然基因序列是否可以申请专利这样的问题发生诉讼，因此测试这些突变的市场被垄断了。

　　Dr Gardner's discovery is that a substance called C-terminal binding⁶ protein (CtBP) helps regulate BRCA1.

　　KG博士发现了一种能够调节BRCA1基因的蛋白质CtBP。

　　Since the activity of CtBP is, itself, governed by the processing of calorie-rich molecules⁸, the more of those molecules the body processes, the more at risk of cancer it becomes.

　　因为CtBP蛋白质本身由加工富含卡路里的分子的过程控制着，所以身体处理越多的这类分子，患癌症的风险就越大。

　　Previous work has shown that CtBP senses the amount of energy in a cell by binding to a small molecule⁷ called NADH.

　　之前的工作表明，CtBP蛋白质通过结合一种叫做NADH的小分子来感知每个细胞中的总能量。

　　This chemical is a by-product⁹ of metabolism¹⁰, and cells that are processing an excessive amount of energy for storage have a superabundance of it compared with the amount of a related molecule called NAD+. As the ratio of NAD+ to NADH falls, CtBP combines with NADH.

　　这种化学物质是新陈代谢的副产物，并且那些处理并存储过剩能量的细胞拥有过剩的NADH分子，和与之有关叫做NAD+的分子比起来。

　　This changes CtBP's shape and enables it to form complexes with several other proteins.

　　这改变了CtBP的形状并使之形成一种带有其他蛋白质的联合体。

　　These complexes control the activity of DNA by shutting off certain genes¹¹.

　　这些联合体通过切断某些基因控制DNA活动。

　　Dr Gardner and his team report in the latest issue of Nature Structural¹² & Molecular¹³ Biology that one of the genes so controlled is BRCA1.

　　KG博士和他的团队在最新一期的《自然结构和分子生物》上宣称，其中这么被控制的基因中就有BRCA1。

　　The protein encoded by BRCA1 is involved in DNA repair.

　　被BRCA1基因编码的蛋白质与DNA修复有关。

　　Cells that lack a working version of it gradually accumulate genetic¹⁴ changes.

　　缺乏它的一个工作版本的细胞们渐渐引起了基因的改变。

　　Though most of these changes either have little impact or will lead to the cell's death, some may promote the formation or progression of tumours¹⁵.

　　尽管多数改变要么影响不大，要么会导致细胞（自身）死亡，但有些可能会刺激肿瘤的形成或恶化。

　　A low NAD+/NADH ratio, according to Dr Gardner's work, has a similar effect to a BRCA1 mutation⁴.

　　据KG博士的研究工作，低水平的NAD+/NADH对BRCA1突变会产生类似作用。

　　It leads to less DNA repair and more mutations.

　　这导致了DNA修复的减少却增加了基因的突变的可能性。

　　That, unfortunately, combines with another effect of too much fat, which is that it stimulates¹⁶ the production of oestrogen by cells that are involved in the storage of fat.

　　不幸的是，这和另外一个过多摄入脂肪的影响就结合起来，过多摄入脂肪通过那些储存脂肪的细胞会刺激雌激素的产生。

　　More oestrogen means more cell proliferation in hormone-sensitive tissues—a category that includes the breasts and the ovaries.

　　更多的雌激素意味着荷尔蒙细胞增殖---这是一种非常敏感的组织---包括乳房和卵巢。

　　Therefore, just when those cells are being told to undergo the error-prone process of replication and division and need their DNA-repair system most, CtBP slashes¹⁷ that system to ribbons.

　　因此，当这些细胞被通知经历可能会出错的复制和分裂过程并需要他们的DNA修复系统时，CtBP就会将此系统破坏。

　　Though this is the first clear link between calorie intake¹⁸ and cancer that has been seen at the molecular level, Dr Gardner says his result is consistent with numerous past experiments.

　　尽管这是摄入热量和癌症之间联系的首次清晰描述，该联系是在分子水平下被发现的，但KG博士说，他的研究结果与之前的大量实验一致。

　　For example, breast tumours are more aggressive and less genetically¹⁹ stable in heavily fed mice than in animals confined to a calorie-restricted diet.

　　例如，与那些吃热量受限制食物的老鼠相比，不加限制的老鼠的乳房肿块更恶性且基因更不稳定。

　　So, along with all the other reasons to keep trim, there is a new one: it may help to keep you free of cancer.

　　因此，和其他保持苗条的所有理由一道，今天多了一条：保持苗条有助于远离癌症。

1 obesity   

n.肥胖，肥大

参考例句：

• One effect of overeating may be obesity.吃得过多能导致肥胖。
• Sugar and fat can more easily lead to obesity than some other foods.糖和脂肪比其他食物更容易导致肥胖。

2 malignant   

adj.恶性的，致命的；恶意的，恶毒的

参考例句：

• Alexander got a malignant slander.亚历山大受到恶意的诽谤。
• He started to his feet with a malignant glance at Winston.他爬了起来，不高兴地看了温斯顿一眼。

3 gene   

n.遗传因子，基因

参考例句：

• A single gene may have many effects.单一基因可能具有很多种效应。
• The targeting of gene therapy has been paid close attention.其中基因治疗的靶向性是值得密切关注的问题之一。

4 mutation   

n.变化，变异，转变

参考例句：

• People who have this mutation need less sleep than others.有这种突变的人需要的睡眠比其他人少。
• So far the discussion has centered entirely around mutation in the strict sense.到目前为止，严格来讲，讨论完全集中于围绕突变问题上。

5 DNA   

(缩)deoxyribonucleic acid 脱氧核糖核酸

参考例句：

• DNA is stored in the nucleus of a cell.脱氧核糖核酸储存于细胞的细胞核里。
• Gene mutations are alterations in the DNA code.基因突变是指DNA密码的改变。

6 binding   

有约束力的，有效的，应遵守的

参考例句：

• The contract was not signed and has no binding force. 合同没有签署因而没有约束力。
• Both sides have agreed that the arbitration will be binding. 双方都赞同仲裁具有约束力。

7 molecule   

n.分子，克分子

参考例句：

• A molecule of water is made up of two atoms of hygrogen and one atom of oxygen.一个水分子是由P妈̬f婘̬ 妈̬成的。
• This gives us the structural formula of the molecule.这种方式给出了分子的结构式。

8 molecules   

分子( molecule的名词复数 )

参考例句：

• The structure of molecules can be seen under an electron microscope. 分子的结构可在电子显微镜下观察到。
• Inside the reactor the large molecules are cracked into smaller molecules. 在反应堆里，大分子裂变为小分子。

9 by-product   

n.副产品，附带产生的结果

参考例句：

• Freedom is the by-product of economic surplus.自由是经济盈余的副产品。
• The raw material for the tyre is a by-product of petrol refining.制造轮胎的原材料是提炼汽油时产生的一种副产品。

10 metabolism   

n.新陈代谢

参考例句：

• After years of dieting,Carol's metabolism was completely out of whack.经过数年的节食，卡罗尔的新陈代谢完全紊乱了。
• All living matter undergoes a process of metabolism.生物都有新陈代谢。

11 genes   

n.基因( gene的名词复数 )

参考例句：

• You have good genes from your parents, so you should live a long time. 你从父母那儿获得优良的基因，所以能够活得很长。 来自《简明英汉词典》
• Differences will help to reveal the functions of the genes. 它们间的差异将会帮助我们揭开基因多种功能。 来自英汉非文学 - 生命科学 - 生物技术的世纪

12 structural   

adj.构造的，组织的，建筑（用）的

参考例句：

• The storm caused no structural damage.风暴没有造成建筑结构方面的破坏。
• The North American continent is made up of three great structural entities.北美大陆是由三个构造单元组成的。

13 molecular   

adj.分子的；克分子的

参考例句：

• The research will provide direct insight into molecular mechanisms.这项研究将使人能够直接地了解分子的机理。
• For the pressure to become zero, molecular bombardment must cease.当压强趋近于零时，分子的碰撞就停止了。

14 genetic   

adj.遗传的，遗传学的

参考例句：

• It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
• Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。

15 tumours   

肿瘤( tumour的名词复数 )

参考例句：

• Blood vessels develop abnormally in cancer tumours. 在癌肿瘤中血管出现不正常。
• This apparatus scans patients' brains for tumours. 这台仪器扫描检查病人的脑瘤。

16 stimulates   

v.刺激( stimulate的第三人称单数 )；激励；使兴奋；起兴奋作用，起刺激作用，起促进作用

参考例句：

• Exercise stimulates the body. 运动促进身体健康。 来自《简明英汉词典》
• Alcohol stimulates the action of the heart. 酒刺激心脏的活动。 来自《现代英汉综合大词典》

17 slashes   

n.（用刀等）砍( slash的名词复数 )；（长而窄的）伤口；斜杠；撒尿v.挥砍( slash的第三人称单数 )；鞭打；割破；削减

参考例句：

• They report substantial slashes in this year's defense outlays. 他们报道今年度国防经费的大量削减。 来自辞典例句
• Inmates suffered injuries ranging from stab wounds and slashes to head trauma. 囚犯们有的被刺伤，有的被砍伤，而有的头部首创，伤势不一而足。 来自互联网

18 intake   

n.吸入，纳入；进气口，入口

参考例句：

• Reduce your salt intake.减少盐的摄入量。
• There was a horrified intake of breath from every child.所有的孩子都害怕地倒抽了一口凉气。

19 genetically   

adv.遗传上

参考例句：

• All the bees in the colony are genetically related. 同一群体的蜜蜂都有亲缘关系。
• Genetically modified foods have already arrived on American dinner tables. 经基因改造加工过的食物已端上了美国人的餐桌。 来自英汉非文学 - 生命科学 - 基因与食物