经济学人278:微生物组学 病毒防护

 　　Science and technology

　　科学技术
　　Microbiomics
　　微生物组学
　　A virus shield
　　病毒防护
　　Viruses help keep people disease-free
　　病毒能够帮助人类免遭疾病
　　THE story of the microbiome—the community of tiny organisms that coexist symbiotically 1 with people and other animals—gets weirder 2 every day.
　　微生物组指的就是能与人类和其他动物互依共存的微有机体群，关于生物体组的传言一天比一天古怪。
　　Until now that story, which has emerged over the past few years, has seemed one of friendly collaboration 3.
　　自其前些年出现至今，已经看作成一种友好互利的合作。
　　In exchange for a place to live, bacteria aid digestion 4 and help regulate their host's metabolism 5.
　　只要它们寄住在寄主体内，细菌可以帮助寄主消化也可以调节寄主的新陈代谢。
　　The story's latest chapter, though, describes a different deal: between the animal host and viruses.
　　但是，关于生物体组的最新研究提出了一种不同的理论：在动物宿主和病毒的关系链之间还有细菌，
　　And in this deal, bacteria are the targets.
　　细菌是需要被消灭的。
　　Jeremy Barr of San Diego State University and his colleagues, who have just published their results in the Proceedings 6 of the National Academy of Sciences, were intrigued 7 by the high concentrations of viruses called bacteriophages in the mucus secreted 8 by soft-tissue membranes 10 ranging from the outer layers of sea anemones 12 via the skins of fish to the mouths of people.
　　来自圣地亚哥分学的Barr及其同事，对叫噬菌体的一类病毒产生了浓厚的兴趣，它广泛存在于软组织膜分泌的粘液中，不管是海葵的外表面、鱼表面还是人类的口腔，他们将这一发现发表在《美国科学院院刊》上。
　　Such membranes are prime targets for pathogens, which is why so many people suffer from throat and lung infections, and upset guts 13.
　　这些软组织膜就是病原体的主要存在区域，这就是为什么许多人会嗓子发炎、肺部感染和得肠炎。
　　Bacteriophages parasitise bacteria, a process pictured schematically above.
　　噬菌体寄生在细菌内，寄生过程难以用一两句话说清楚。
　　Dr Barr wondered if they were actively 14 working with their hosts to keep down the level of pathogenic bugs 16 that might otherwise set up shop in the hosts' mucus membranes.
　　Barr博士觉得噬菌体或许可以帮助寄主降低致病菌的数量，防止病菌将在寄主的粘膜液中大量繁殖。
　　Regardless of which type of membrane 9 they looked at, Dr Barr and his colleagues found about four times more phages per bacterium 17 in the mucus than were in its immediate 18 surroundings.
　　Barr博士和他的同事发现，无论在何种类型粘液中，每一个病菌对应噬菌体的数量要比粘液附近其他组织里的多四倍。
　　This suggested that phages are sticking specifically to mucus, and in an elegant series of experiments they found that this was true and that the thing on a phage which is doing the sticking is a “hypervariable” protein called Hoc.
　　这暗示噬菌体特定存在于粘液中，在一系列巧妙的实验之后，他们发现确实是这样并且发现噬菌体上存在一种称为Hoc的高变蛋白，正是由于这种蛋白质才会使噬菌体特定存在粘液中。
　　Hypervariable proteins come in thousands of slightly different versions.
　　细分的话，高变蛋白有好几千种。
　　The best studied is the mammalian antibody protein, immunoglobulin.
　　对这类蛋白研究最深入的要属哺乳动物抗体蛋白—免疫球蛋白。
　　Each of the versions of this protein that exist in every individual is capable of locking onto and neutralising a different invading pathogen, by interacting with different molecules 20 on the pathogen's surface.
　　人体内有各种高变蛋白的噬菌体，噬菌体通过识别不同细菌的表面分子，做到一种噬菌体只侵噬一种入侵细菌。
　　In phages, Dr Barr discovered, the various versions of Hoc stick to the varied 21 branched sugar molecules characteristic of mucus.
　　Barr博士发现不同的HOC蛋白与不同的粘液特征性多糖分子的支链相结合。
　　That helps the phages, because their bacterial 22 prey 23 also accumulate in mucus, which is thus a rich hunting ground.
　　因为细菌的侵染过程也是发生在粘液中，这就为噬菌体提供了大量的寄生宿主。
　　And it helps the animal host, be that host sea anemone 11, fish or human being, by stopping any particular bacterial species running out of control—for if a species does start to multiply, which is a normal precursor 24 to infection, there will be more phages around to attack it and multiply in their turn, bringing the uppity bug 15 rapidly under control.
　　这也帮助诸如海葵、鱼、人类一样的动物寄主防止某种细菌大量繁殖，因为细菌要感染宿主就必须先大量繁殖，这样周围会聚集更多的噬菌体来侵噬它们，并且噬菌体开始繁殖，迅速控制住这繁殖快速的细菌的数量。
　　The phages are thus acting 19 as a backup immune system for their hosts, and one whose mode of operation has a surprising parallel with that of the more familiar antibody-based system.
　　对于寄主来说，噬菌体属于免疫系统的一部分，并且噬菌体的这种免疫系统与与它很相似的抗体免疫系统不相伯仲。
　　1.coexist with 与…同时存在，与…共存
　　That is to say, it coexists with poetic 25 language.
　　这就是说，实用语言和诗歌语言并存。
　　That is the trick, after all, of Ms. Shteynshleyger's work: Prickly self-protection coexists with supreme 26 vulnerability.
　　毕竟这就是Shteynshleyger作品的技巧所在：仙人掌形的自我保护与极端的内心脆弱并存。
　　2.in exchange for 交换
　　Mr monti's big idea is a swap 27: liberalism in exchange for redistribution.
　　蒙逖先生的妙计是一个互换机制：自由主义交换再分配。
　　You'll get free accommodation in exchange for watering some plants and walking a dog.
　　你将会获得免费住宿，与此相交换的就是你要做一些植物浇水、遛狗的工作。
　　3.prime target 主要目标
　　It's a prime target for terrorist attacks.
　　这是恐怖分子攻击的首要目标。
　　One prime target has been cash management for chinese companies that are expanding abroad.
　　一个主要目标是在海外扩张的中国企业的现金管理。
　　4.keep down 控制；使不升起；使留级
　　They try to keep down the cost of living.
　　他们努力压低生活费。
　　Keep down, stay still.
　　保持低姿势不要动！