2022年经济学人 肠道细菌可以帮助绵羊抵御线虫的侵袭

Science & technology

科技版块

Sheep farming

绵羊养殖

Turning the worms

改变蠕虫

Gut¹ bacteria may help fight nematode infestations² in sheep

肠道细菌可以帮助绵羊抵御线虫的侵袭

Sheep farmers in Australia and New Zealand have a problem.

澳大利亚和新西兰的牧羊人有一个问题。

Their charges are susceptible³ to intestinal⁴ nematode worms which cause them to waste away and can, in severe cases, kill them.

他们的羊群容易受到肠道线虫的影响，这些蠕虫会使它们日渐消瘦，在严重的情况下，会令它们死亡。

Over the years, the worms have evolved resistance to drugs once used to attack them.

多年来，这些蠕虫已经对曾经攻击它们的药物产生了抗药性。

But a second approach is to breed countermeasures into the sheep themselves.

但第二种方法是在绵羊体内培育对策。

This can be done by counting the number of worm eggs in animals' droppings and selecting as sires and dams those that have the fewest, on the assumption that these are the sheep with the least worm-friendly guts⁵, and that this property will show up in their offspring as well.

这可以通过计算动物粪便中的虫卵数量，并选择那些虫卵最少的作为公羊和母羊培育后代，假设这些羊的肠道对虫子最不友好，这种特性也会在它们的后代中表现出来。

That works.

这很管用。

But how, has been obscure.

但如何做到这一点还是个未知数。

A study just published in Animal Microbiome, by Erwin Paz of the University of Western Australia and his colleagues, throws light on the matter.

西澳大利亚大学的Erwin Paz和他的同事刚刚在《动物微生物组》上发表的一项研究揭示了这一问题。

It suggests that what is being bred for is a propensity⁶ to develop a worm-hostile gut microbiome.

这表明，繁殖的目的是为了培养一种对蠕虫不利的肠道微生物群。

Gut microbial health, once a fringe medical interest, is now mainstream⁷ for human beings, as bugs⁸ in the alimentary⁹ canal are linked with conditions ranging from obesity¹⁰ to arthritis¹¹.

肠道微生物健康曾经是一种边缘医学关注点，现在已经成为人类的主流，因为消化道中的细菌与肥胖、关节炎等一系列疾病有关。

But what is true of people is true of other animals, too.

对人类来说是这样的，对其他动物也是这样。

And, in the case of sheep, Dr Paz and his collaborators seem to have hit the jackpot.

在绵羊的例子中，Paz博士和他的合作者似乎大获成功。

Dr Paz knew from past work that sheep with severe worm infestations tend to have abnormal bacterial¹² populations in their faeces.

Paz博士从过去的工作中了解到，患有严重蠕虫感染的绵羊的粪便中往往细菌种群不正常。

This led him to wonder whether the bugs in the guts of resistant¹³ sheep were somehow hampering¹⁴ the worms' activities.

这让他很好奇，抗蠕虫绵羊肠道中的细菌是否以某种方式阻碍了蠕虫的活动。

He and his team therefore looked at a flock of 200 sheep at a farm in Western Australia and selected ten that had particularly high loads of worm eggs in their faeces (1,940 per gram, on average) and ten that had low loads (410 per gram).

因此，他和他的团队研究了西澳大利亚一个农场的200只绵羊，选择了10只粪便中虫卵含量特别高的羊(平均每克含1940只蠕虫)和10只虫卵含量低的(每克含410只蠕虫)。

These unfortunate sacrificial beasts were then slaughtered¹⁵ and their entrails examine -- not for auguries¹⁶ of the future but for their microbial populations.

这些不幸的绵羊随后被屠宰，并检查了它们的内脏——不是为了预示未来，而是为了检查它们体内的微生物种群。

As they had hoped to, the researchers did indeed find systematic¹⁷ differences between the microbiomes of the two groups.

正如他们所希望的那样，研究人员确实发现了两组微生物群之间的系统性差异。

These differences were particularly notable in the small intestine¹⁸, where the worms live, with resistant sheep having richer and more diverse bacterial populations in this part of the gut than vulnerable animals did.

这些差异在蠕虫生活的小肠中尤为明显，与易受感染的动物相比，抗蠕虫绵羊在肠道的这一部分拥有更丰富和更多样化的细菌种群。

In particular, the team noticed that populations of bacteria which ferment¹⁹ carbohydrates²⁰ such as cellulose and turn them into short-chain fatty acids were especially abundant in the resistant animals.

特别是，研究小组注意到，在抗蠕虫绵羊体内，可将其转化为短链脂肪酸的发酵纤维素等碳水化合物细菌种群尤其丰富。

It is, of course, possible, that the worms are affecting the sheep's microbiomes, rather than the other way around.

当然，有可能是蠕虫影响了绵羊体内的生物群，而不是体内生物群影响了蠕虫。

But Dr Paz thinks this is unlikely, because all of the sheep looked at had at least some worms.

但Paz博士认为这不太可能，因为所有被观察的绵羊都或多或少有一些蠕虫。

Rather, he suspects, genetically²¹ resistant sheep are providing an intestinal environment conducive²² to bacteria which either produce compounds that repel²³ the worms or consume resources which the worms depend upon.

相反，他怀疑，具有基因抗性的绵羊正在提供一个有利于细菌的肠道环境，这些细菌要么产生驱除蠕虫的化合物，要么消耗蠕虫所依赖的资源。

If that is correct, it opens up a third approach to worm control, which is to employ probiotics to shape the gut microbiomes of flocks directly, rather than relying on selective breeding to do it at one remove.

如果这个猜想正确的，它开辟了第三种控制蠕虫的方法，即使用益生菌直接塑造羊群的肠道微生物群，而不是依赖于选择性繁殖一次完成。

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 infestations   

n.（害虫、盗贼等）群袭，出没，横行( infestation的名词复数 )

参考例句：

• The arrival of warm weather raises the specter of disease and increased rat infestations caused by rotting garbage. 天气转暖使人们担心垃圾腐烂会引起疾病传播和鼠群猖獗。 来自《简明英汉词典》
• Piperazine citrate is the drug of choice in the treatment of Ascaris infestations. 枸橼酸哌嗪治疗蛔虫感染是最好的药物。 来自辞典例句

3 susceptible   

adj.过敏的，敏感的；易动感情的，易受感动的

参考例句：

• Children are more susceptible than adults.孩子比成人易受感动。
• We are all susceptible to advertising.我们都易受广告的影响。

4 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

5 guts   

v.狼吞虎咽，贪婪地吃，飞碟游戏（比赛双方每组5人，相距15码，互相掷接飞碟）；毁坏（建筑物等）的内部( gut的第三人称单数 )；取出…的内脏n.勇气( gut的名词复数 )；内脏；消化道的下段；肠

参考例句：

• I'll only cook fish if the guts have been removed. 鱼若已收拾干净，我只需烧一下即可。
• Barbara hasn't got the guts to leave her mother. 巴巴拉没有勇气离开她妈妈。 来自《简明英汉词典》

6 propensity   

n.倾向；习性

参考例句：

• He has a propensity for drinking too much alcohol.他有酗酒的倾向。
• She hasn't reckoned on his propensity for violence.她不曾料到他有暴力倾向。

7 mainstream   

n.（思想或行为的）主流；adj.主流的

参考例句：

• Their views lie outside the mainstream of current medical opinion.他们的观点不属于当今医学界观点的主流。
• Polls are still largely reflects the mainstream sentiment.民调还在很大程度上反映了社会主流情绪。

8 bugs   

adj.疯狂的，发疯的n.窃听器( bug的名词复数 )；病菌；虫子；[计算机]（制作软件程序所产生的意料不到的）错误

参考例句：

• All programs have bugs and need endless refinement. 所有的程序都有漏洞，都需要不断改进。 来自《简明英汉词典》
• The sacks of rice were swarming with bugs. 一袋袋的米里长满了虫子。 来自《简明英汉词典》

9 alimentary   

adj.饮食的，营养的

参考例句：

• He had the disease of alimentary canal.他患了消化道疾病。
• This system is mainly a long tube,called the alimentary canal.这一系统主要是一根长管，称作消化道。

10 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。

11 arthritis   

n.关节炎

参考例句：

• Rheumatoid arthritis has also been linked with the virus.风湿性关节炎也与这种病毒有关。
• He spent three months in the hospital with acute rheumatic arthritis.他患急性风湿性关节炎，在医院住了三个月。

12 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。

13 resistant   

adj.(to)抵抗的，有抵抗力的

参考例句：

• Many pests are resistant to the insecticide.许多害虫对这种杀虫剂有抵抗力。
• They imposed their government by force on the resistant population.他们以武力把自己的统治强加在持反抗态度的人民头上。

14 hampering   

妨碍，束缚，限制( hamper的现在分词 )

参考例句：

• So fraud on cows and development aid is seriously hampering growth. 因此在牛问题上和发展补助上的诈骗严重阻碍了发展。
• Short-termism, carbon-trading, disputing the science-are hampering the implementation of direct economically-led objectives. 短效主义，出售二氧化碳，进行科学辩论，这些都不利于实现以经济为主导的直接目标。

15 slaughtered   

v.屠杀，杀戮，屠宰( slaughter的过去式和过去分词 )

参考例句：

• The invading army slaughtered a lot of people. 侵略军杀了许多人。 来自《简明英汉词典》
• Hundreds of innocent civilians were cruelly slaughtered. 数百名无辜平民遭残杀。 来自《简明英汉词典》

16 auguries   

n.（古罗马）占卜术，占卜仪式( augury的名词复数 )；预兆

参考例句：

• So far, the auguries look gloomy. 但迄今为止，前景似乎不容乐观。 来自互联网

17 systematic   

adj.有系统的，有计划的，有方法的

参考例句：

• The way he works isn't very systematic.他的工作不是很有条理。
• The teacher made a systematic work of teaching.这个教师进行系统的教学工作。

18 intestine   

adj.内部的；国内的；n.肠

参考例句：

• This vitamin is absorbed through the walls of the small intestine.这种维生素通过小肠壁被吸收。
• The service productivity is the function,including external efficiency,intestine efficiency and capacity efficiency.服务业的生产率是一个包含有外部效率、内部效率和能力效率的函数。

19 ferment   

vt.使发酵；n./vt.（使）激动，（使）动乱

参考例句：

• Fruit juices ferment if they are kept a long time.果汁若是放置很久，就会发酵。
• The sixties were a time of theological ferment.六十年代是神学上骚动的时代。

20 carbohydrates   

n.碳水化合物，糖类( carbohydrate的名词复数 )；淀粉质或糖类食物

参考例句：

• The plant uses the carbohydrates to make cellulose. 植物用碳水化合物制造纤维素。 来自《简明英汉词典》
• All carbohydrates originate from plants. 所有的碳水化合物均来自植物。 来自辞典例句

21 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

22 conducive   

adj.有益的，有助的

参考例句：

• This is a more conducive atmosphere for studying.这样的氛围更有利于学习。
• Exercise is conducive to good health.体育锻炼有助于增强体质。

23 repel   

v.击退，抵制，拒绝，排斥

参考例句：

• A country must have the will to repel any invader.一个国家得有决心击退任何入侵者。
• Particles with similar electric charges repel each other.电荷同性的分子互相排斥。