经济学人189:肠道细菌可以影响人的情绪

 　　Bacteria and behaviour

　　细菌和行为学

　　Gut¹ instinct

　　肠道反应

　　Tantalising evidence that intestinal² bacteria can influence mood

　　逗引的证据表明，肠道细菌可以影响人的情绪

　　Sep 3rd 2011 | from the print edition

　　A GOOD way to make yourself unpopular at dinner parties is to point out that a typical person is, from a microbiologist’s perspective, a walking, talking Petri dish. An extraordinary profusion³ of microscopic⁴ critters inhabit every crack and crevice⁵ of the typical human, so many that they probably outnumber the cells of the body upon and within which they dwell.

　　一个让你自己在晚宴上不受欢迎的好方式就是，从微生物学家的角度指出，一位有代表性的人就是一个会走动并会说话的皮氏培养皿。每位有代表性的人的裂纹和缝隙里生活着无数的微小生物，它们的数目如此之多可能超过它们所依靠并栖息的人体细胞。

　　Happily, these microbes are mostly harmless. Some of them, particularly those that live in the gut, are positively⁶ beneficial, helping⁷ with digestion⁸ and keeping the intestines⁹ in good working order. That is no surprise—bacteria as much as people have an interest in keeping their homes in sound condition. What is surprising is the small but growing body of evidence which suggests that bacteria dwelling¹⁰ in the gut can affect the brain, too, and thereby¹¹ influence an individual’s mood and behaviour. The most recent paper on the topic, published this week in the Proceedings¹² of the National Academy of Sciences, reports (like much of the research in this field) on results in mice.

　　幸运地是，这些微生物大部分都是无害的。其中一些，特别是那些生活在消化道里的微生物，实际上是有益的，不仅有助于消化还保持肠道良好的工作秩序。这毫不奇怪——细菌和人一样也喜欢保持家园状态完好。奇怪的是，虽然数量不多，但越来越多的证据表明，生活在肠道的细菌也可能影响大脑，继而影响个人的情绪和行为。本周有关该主题的论文刊登在《美国国家科学院院刊》的一篇文章报道（像这个领域的许多研究一样）了应用小鼠的实验结果。

　　The researchers, led by Javier Bravo of University College, Cork¹³, split their rodent¹⁴ subjects into two groups. One lot were fed a special broth¹⁵ containing Lactobacillus rhamnosus, a gut-dwelling bacterium¹⁶ often found in yogurt and other dairy products. The others were fed an ordinary diet, not fortified¹⁷ with microbes.

　　科克大学学院的哈维尔?布拉沃（Javier Bravo）带领下的研究人员将这些啮齿目动物分成两组。一组以一种在酸奶和其它乳制品中经常发现的含乳酸杆菌属鼠李糖乳杆菌（学名为Lactobacillus rhamnosus）的特别液体培养基喂食。另一组则以不用微生物强化的一般食物喂食。

　　The team then subjected the mice to a battery of tests that are used routinely to measure the emotional states of rodents¹⁸. Most (though not all) of these tests showed significant differences between the two groups of animals.

　　然后，研究组人员对小鼠进行了一套测试。这套测试经常用于衡量啮齿类动物的情感状态。大部分（虽然不是所有的）测试表明，两组动物之间有着显著的不同。

　　One test featured a maze¹⁹ that had both enclosed and open tunnels. The researchers found that the bacterially boosted mice ventured out into the open twice as often as the control mice, which they interpreted to mean that these rodents were more confident and less anxious than those not fed Lactobacillus.

　　一个测试是以封闭和敞开的隧道迷宫为特点。研究人员发现，喂食了李糖乳杆菌的小鼠更经常冒险进入敞开的隧道，而且次数是对照小鼠的两倍之多。他们的解释意味着这些啮齿类动物比那些没有喂食李糖乳杆菌的小鼠更有信心而且焦虑更少。

　　In another test the animals were made to swim in a container from which they could not escape. Bacteria-fed mice attempted to swim for longer than the others before they gave up and had to be rescued. Such persistence²¹ is usually interpreted by students of rodent behaviour as evidence of a more positive mood.

　　在另一组测试中，研究人员让这些动物在一个无法逃脱的容器内游泳。在这些小鼠放弃游泳并不得不被救出之前，李糖乳杆菌喂养的小鼠试图游泳的时间比其它小鼠更长。这种持久性经常被研究啮齿类动物行为的学生解释为更积极情绪的证据。

　　Direct measurements of the animals’ brains supported the behavioural results. Levels of corticosterone, a stress hormone²², were markedly lower in the bacteria-fed mice than they were in the control group when both groups were exposed to stressful situations. The number of receptors for gamma-aminobutyric acid, a natural chemical messenger that helps dampen the activity of certain nerve cells, varied²³ in statistically²⁴ significant ways between the brains of the two groups, with more in some parts of the treated animals’ brains and fewer in others. Most intriguing²⁵ of all, when Dr Bravo cut the animals’ vagus nerves—which transmit signals between the gut and the brain—the differences between the groups vanished.

　　对这些动物大脑的多次直接测量结果支持了行为学方面的效果。当两组小鼠进行应激实验时，喂食李糖乳杆菌的小鼠体内的应激激素皮质甾酮含量比那些对照组的小鼠体内要明显低地多。γ-氨基丁酸是有助于抑制特定神经细胞活动的自然化学信使。两组小鼠的大脑中γ-氨基丁酸感受器的数目以统计学上显著的方式改变。γ-氨基丁酸感受器在处理过的小鼠大脑的一些部分出现较多些，而在没有处理过的小鼠大脑内则少些。最引人注目的是，当布拉沃博士（Dr Bravo）切断这些动物的迷走神经---传输肠道和大脑之间的信号---两组小鼠间的差异突然消失了。

　　The idea that gut-dwelling microbes can affect an animal’s state of mind may strike some people as outlandish, and there are certainly loose ends still to be tied up. Beyond their evidence that the vagus nerve is crucial to the relationship, for example, Dr Bravo and his colleagues do not yet know the precise mechanisms²⁶ at work. There is also an obvious follow-up question: whether a similar thing is going on in people. A few previous studies have hinted at the possibility. For example, bacterial²⁰ treatments may help with the mental symptoms of illnesses such as irritable-bowel syndrome²⁷.

　　这个想法---生活在肠道里的微生物能够影响动物的精神状态---可能给一些人留下稀奇古怪的印象，而且肯定还有一些零星问题有待解决。他们手头的证据无法证明迷走神经对动物之间的关系至关重要，比如，布拉沃博士和其同事至今还不知道其起作用的明确机制。况且还有一个明显的后续问题：人类是否也有类似的情况。以前的几个研究已经暗示这种可能性。例如，细菌的治疗方法可能有助于改善诸如肠易激综合症疾病的精神症状。

　　All this is forcing a reassessment of people’s relationship with the bacteria that live on and in them, which have long been regarded mainly as a potential source of infections. An editorial in this week’s Nature raises the possibility that the widespread prescription²⁸ of antibiotics—which kill useful bacteria as effectively as hostile ones—might be one factor behind rising rates of asthma²⁹, diabetes³⁰ and irritable-bowel syndrome. If Dr Bravo’s results apply to people, too, then mood disorders³¹ may end up being added to this list.

　　所有这一切正在迫使人类重新评估自身与这些栖居于人体而且人类依靠它们维持生命的细菌之间的关系。长期以来，这些细菌主要被认为是潜在的感染源。本周《自然杂志》的社论提出了一种可能性，广泛使用的抗生素处方---抗生素杀死有益菌的有效性就像杀死不利的细菌一样---可能是哮喘，糖尿病和肠易激综合症比例上升的真正因素之一。假如布拉沃博士（Dr Bravo）的结果也应用于人类，那么情感障碍可能最终被添加到这个目录上。

1 gut   

n.[pl.]胆量；内脏；adj.本能的；vt.取出内脏

参考例句：

• It is not always necessary to gut the fish prior to freezing.冷冻鱼之前并不总是需要先把内脏掏空。
• My immediate gut feeling was to refuse.我本能的直接反应是拒绝。

2 intestinal   

adj.肠的；肠壁；肠道细菌

参考例句：

• A few other conditions are in high intestinal obstruction. 其它少数情况是高位肠梗阻。 来自辞典例句
• This complication has occasionally occurred following the use of intestinal antiseptics. 这种并发症偶而发生在使用肠道抗菌剂上。 来自辞典例句

3 profusion   

n.挥霍；丰富

参考例句：

• He is liberal to profusion.他挥霍无度。
• The leaves are falling in profusion.落叶纷纷。

4 microscopic   

adj.微小的，细微的，极小的，显微的

参考例句：

• It's impossible to read his microscopic handwriting.不可能看清他那极小的书写字迹。
• A plant's lungs are the microscopic pores in its leaves.植物的肺就是其叶片上微细的气孔。

5 crevice   

n.(岩石、墙等)裂缝；缺口

参考例句：

• I saw a plant growing out of a crevice in the wall.我看到墙缝里长出一棵草来。
• He edged the tool into the crevice.他把刀具插进裂缝里。

6 positively   

adv.明确地，断然，坚决地；实在，确实

参考例句：

• She was positively glowing with happiness.她满脸幸福。
• The weather was positively poisonous.这天气着实讨厌。

7 helping   

n.食物的一份&adj.帮助人的，辅助的

参考例句：

• The poor children regularly pony up for a second helping of my hamburger. 那些可怜的孩子们总是要求我把我的汉堡包再给他们一份。
• By doing this, they may at times be helping to restore competition. 这样一来, 他在某些时候,有助于竞争的加强。

8 digestion   

n.消化，吸收

参考例句：

• This kind of tea acts as an aid to digestion.这种茶可助消化。
• This food is easy of digestion.这食物容易消化。

9 intestines   

n.肠( intestine的名词复数 )

参考例句：

• Perhaps the most serious problems occur in the stomach and intestines. 最严重的问题或许出现在胃和肠里。 来自辞典例句
• The traps of carnivorous plants function a little like the stomachs and small intestines of animals. 食肉植物的捕蝇器起着动物的胃和小肠的作用。 来自辞典例句

10 dwelling   

n.住宅，住所，寓所

参考例句：

• Those two men are dwelling with us.那两个人跟我们住在一起。
• He occupies a three-story dwelling place on the Park Street.他在派克街上有一幢3层楼的寓所。

11 thereby   

adv.因此，从而

参考例句：

• I have never been to that city,,ereby I don't know much about it.我从未去过那座城市，因此对它不怎么熟悉。
• He became a British citizen,thereby gaining the right to vote.他成了英国公民，因而得到了投票权。

12 proceedings   

n.进程，过程，议程；诉讼(程序)；公报

参考例句：

• He was released on bail pending committal proceedings. 他交保获释正在候审。
• to initiate legal proceedings against sb 对某人提起诉讼

13 cork   

n.软木，软木塞

参考例句：

• We heard the pop of a cork.我们听见瓶塞砰的一声打开。
• Cork is a very buoyant material.软木是极易浮起的材料。

14 rodent   

n.啮齿动物；adj.啮齿目的

参考例句：

• When there is a full moon,this nocturnal rodent is careful to stay in its burrow.月圆之夜，这种夜间活动的啮齿类动物会小心地呆在地洞里不出来。
• This small rodent can scoop out a long,narrow tunnel in a very short time.这种小啮齿动物能在很短的时间里挖出一条又长又窄的地道来。

15 broth   

n.原(汁)汤(鱼汤、肉汤、菜汤等)

参考例句：

• Every cook praises his own broth.厨子总是称赞自己做的汤。
• Just a bit of a mouse's dropping will spoil a whole saucepan of broth.一粒老鼠屎败坏一锅汤。

16 bacterium   

n.(pl.)bacteria 细菌

参考例句：

• The bacterium possibly goes in the human body by the mouth.细菌可能通过口进入人体。
• A bacterium is identified as the cause for his duodenal ulcer.一种细菌被断定为造成他十二指肠溃疡的根源。

17 fortified   

adj. 加强的

参考例句：

• He fortified himself against the cold with a hot drink. 他喝了一杯热饮御寒。
• The enemy drew back into a few fortified points. 敌人收缩到几个据点里。

18 rodents   

n.啮齿目动物( rodent的名词复数 )

参考例句：

• Rodents carry diseases and are generally regarded as pests. 啮齿目动物传播疾病，常被当作害虫对待。 来自《简明英汉词典》
• Some wild rodents in Africa also harbor the virus. 在非洲，有些野生啮齿动物也是储毒者。 来自辞典例句

19 maze   

n.迷宫，八阵图，混乱，迷惑

参考例句：

• He found his way through the complex maze of corridors.他穿过了迷宮一样的走廊。
• She was lost in the maze for several hours.一连几小时，她的头脑处于一片糊涂状态。

20 bacterial   

a.细菌的

参考例句：

• Bacterial reproduction is accelerated in weightless space. 在失重的空间，细菌繁殖加快了。
• Brain lesions can be caused by bacterial infections. 大脑损伤可能由细菌感染引起。

21 persistence   

n.坚持，持续，存留

参考例句：

• The persistence of a cough in his daughter puzzled him.他女儿持续的咳嗽把他难住了。
• He achieved success through dogged persistence.他靠着坚持不懈取得了成功。

22 hormone   

n.荷尔蒙，激素，内分泌

参考例句：

• Hormone implants are used as growth boosters.激素植入物被用作生长辅助剂。
• This hormone interacts closely with other hormones in the body.这种荷尔蒙与体內其他荷尔蒙紧密地相互作用。

23 varied   

adj.多样的，多变化的

参考例句：

• The forms of art are many and varied.艺术的形式是多种多样的。
• The hotel has a varied programme of nightly entertainment.宾馆有各种晚间娱乐活动。

24 statistically   

ad.根据统计数据来看，从统计学的观点来看

参考例句：

• The sample of building permits is larger and therefore, statistically satisfying. 建筑许可数的样本比较大，所以统计数据更令人满意。
• The results of each test would have to be statistically independent. 每次试验的结果在统计上必须是独立的。

25 intriguing   

adj.有趣的；迷人的v.搞阴谋诡计(intrigue的现在分词)；激起…的好奇心

参考例句：

• These discoveries raise intriguing questions. 这些发现带来了非常有趣的问题。
• It all sounds very intriguing. 这些听起来都很有趣。 来自《简明英汉词典》

26 mechanisms   

n.机械( mechanism的名词复数 )；机械装置；[生物学] 机制；机械作用

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。 来自《简明英汉词典》
• He explained how the two mechanisms worked. 他解释这两台机械装置是如何工作的。 来自《简明英汉词典》

27 syndrome   

n.综合病症；并存特性

参考例句：

• The Institute says that an unidentified virus is to blame for the syndrome. 该研究所表示,引起这种综合症的是一种尚未确认的病毒。
• Results indicated that 11 fetuses had Down syndrome. 结果表明有11个胎儿患有唐氏综合征。

28 prescription   

n.处方，开药；指示，规定

参考例句：

• The physician made a prescription against sea- sickness for him.医生给他开了个治晕船的药方。
• The drug is available on prescription only.这种药只能凭处方购买。

29 asthma   

n.气喘病，哮喘病

参考例句：

• I think he's having an asthma attack.我想他现在是哮喘病发作了。
• Its presence in allergic asthma is well known.它在过敏性气喘中的存在是大家很熟悉的。

30 diabetes   

n.糖尿病

参考例句：

• In case of diabetes, physicians advise against the use of sugar.对于糖尿病患者，医生告诫他们不要吃糖。
• Diabetes is caused by a fault in the insulin production of the body.糖尿病是由体內胰岛素分泌失调引起的。

31 disorders   

n.混乱( disorder的名词复数 )；凌乱；骚乱；（身心、机能）失调

参考例句：

• Reports of anorexia and other eating disorders are on the increase. 据报告，厌食症和其他饮食方面的功能紊乱发生率正在不断增长。 来自《简明英汉词典》
• The announcement led to violent civil disorders. 这项宣布引起剧烈的骚乱。 来自《简明英汉词典》