2023年经济学人 超级细菌的秘密(2)

 

    But such “transductions” cannot fully¹ explain the speed with which bacteria evolve resistance either.

    但是这种“转导”也不能完全解释细菌进化出耐药性的速度。

    It happens rarely, and transfers only small chunks² of DNA³ when it does.

    这种情况很少发生，即使发生，也只会转移一小块DNA。

    In 2018 Dr Chen identified another mechanism⁴, known as lateral⁵ transduction.

    2018年，陈博士发现了另一种机制，即侧向转导。

    This happens when phages, rather than killing⁶ their hosts immediately, integrate their genomes into those of their prey⁷.

    当噬菌体不是立即杀死宿主，而是将自己的基因组整合到猎物的基因组中时，就会发生这种情况。

    When the phages replicate⁸, they read their own genes⁹ from the bacteria’s genome, but sometimes grab copies of long neighbouring stretches of bacterial¹⁰ DNA too, which they carry to infect new hosts.

    当噬菌体复制时，它们利用细菌的基因组读取自己的基因，但有时也会拷贝邻近细菌的长片段DNA，它们携带这些复制品来感染新的宿主。

    Dr Chen reckons that phages could in this way end up stealing up to a quarter of their host’s genome.

    陈博士认为噬菌体可以通过这种方式窃取四分之一的宿主基因组。

    He estimates that lateral transduction is thousands of times faster than other mechanisms¹¹, making it a candidate as the chief driver of microbial drug resistance.

    他估计，横向转导比其他机制快数千倍，已经成为了微生物耐药性的主要驱动因素。

    In practice, this means a bacterium¹² with no previous exposure to antibiotics¹³ could acquire the genes necessary for resistance in a matter of minutes.

    实际上，这意味着以前没有接触过抗生素的细菌可以在几分钟内获得耐药性所需的基因。

    But the story does not end there.

    但故事并没有就此结束。

    Dr Chen examined Staphylococcus aureus, a bacterium that is usually harmless but which can occasionally cause serious illnesses.

    陈医生检查了金黄色葡萄球菌，这种细菌通常是无害的，但偶尔也会引起严重的疾病。

    Particular chunks of its genome, called “pathogenicity islands” (or Sapis), seem to behave like genetic¹⁴ parasites¹⁵; bits of DNA that replicate selfishly without regard for the well-being¹⁶ of their host.

    其基因组的特定部分，称为“致病性岛”(或致病岛)，似乎表现得像是遗传寄生物; 这些DNA片段会自私地复制，不顾宿主的健康。

    In one sense, that makes them an even more primitive¹⁷ form of replicator than a virus.

    从某种意义上说，这会使它们成为比病毒更原始的复制因子。

    When a bacterial cell playing host to a Sapi is infected by a phage, the Sapis can command the cell to produce a protein called small transferase.

    当作为致病岛宿主的细菌细胞被噬菌体感染时，致病岛可以命令细胞产生一种称为小转移酶的蛋白质。

    This is similar to the protein that the attacking phage uses as a signal to begin packing its DNA into newly produced phages.

    这类似于攻击型噬菌体的蛋白质，它会作为信号，开始将自身DNA打包到新产生的噬菌体中。

    That biochemical trick can cause new phages to be packaged not with viral DNA at all, but with long chunks of bacterial genome.

    这种生化技巧可以导致新的噬菌体完全不是用病毒DNA包装的，而是用长段细菌基因组包装的。

    “It completely replaces the phage genome,” says Dr Chen.

    “它完全取代了噬菌体基因组，”陈博士说。

1 fully   

adv.完全地，全部地，彻底地；充分地

参考例句：

• The doctor asked me to breathe in,then to breathe out fully.医生让我先吸气，然后全部呼出。
• They soon became fully integrated into the local community.他们很快就完全融入了当地人的圈子。

2 chunks   

厚厚的一块( chunk的名词复数 )； （某物）相当大的数量或部分

参考例句：

• a tin of pineapple chunks 一罐菠萝块
• Those chunks of meat are rather large—could you chop them up a bIt'smaller? 这些肉块相当大，还能再切小一点吗？

3 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。

4 mechanism   

n.机械装置；机构，结构

参考例句：

• The bones and muscles are parts of the mechanism of the body.骨骼和肌肉是人体的组成部件。
• The mechanism of the machine is very complicated.这台机器的结构是非常复杂的。

5 lateral   

adj.侧面的，旁边的

参考例句：

• An airfoil that controls lateral motion.能够控制横向飞行的机翼。
• Mr.Dawson walked into the court from a lateral door.道森先生从一个侧面的门走进法庭。

6 killing   

n.巨额利润；突然赚大钱，发大财

参考例句：

• Investors are set to make a killing from the sell-off.投资者准备清仓以便大赚一笔。
• Last week my brother made a killing on Wall Street.上个周我兄弟在华尔街赚了一大笔。

7 prey   

n.被掠食者，牺牲者，掠食；v.捕食，掠夺，折磨

参考例句：

• Stronger animals prey on weaker ones.弱肉强食。
• The lion was hunting for its prey.狮子在寻找猎物。

8 replicate   

v.折叠，复制，模写；n.同样的样品；adj.转折的

参考例句：

• The DNA of chromatin must replicate before cell division.染色质DNA在细胞分裂之前必须复制。
• It is also easy to replicate,as the next subsection explains.就像下一个小节详细说明的那样，它还可以被轻易的复制。

9 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

10 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。

11 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》

12 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。

13 antibiotics   

n.（用作复数）抗生素；（用作单数）抗生物质的研究；抗生素，抗菌素( antibiotic的名词复数 )

参考例句：

• the discovery of antibiotics in the 20th century 20世纪抗生素的发现
• The doctor gave me a prescription for antibiotics. 医生给我开了抗生素。

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 parasites   

寄生物( parasite的名词复数 )； 靠他人为生的人； 诸虫

参考例句：

• These symptoms may be referable to virus infection rather than parasites. 这些症状也许是由病毒感染引起的，而与寄生虫无关。
• Kangaroos harbor a vast range of parasites. 袋鼠身上有各种各样的寄生虫。

16 well-being   

n.安康，安乐，幸福

参考例句：

• He always has the well-being of the masses at heart.他总是把群众的疾苦挂在心上。
• My concern for their well-being was misunderstood as interference.我关心他们的幸福，却被误解为多管闲事。

17 primitive   

adj.原始的；简单的；n.原(始)人，原始事物

参考例句：

• It is a primitive instinct to flee a place of danger.逃离危险的地方是一种原始本能。
• His book describes the march of the civilization of a primitive society.他的著作描述了一个原始社会的开化过程。