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SSS 2010-09-01

时间:2010-10-08 03:18来源:互联网 提供网友:xn0006   字体: [ ]
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    (单词翻译:双击或拖选)

There’s been an unexpected development in our understanding of drug resistance in bacteria. The accepted scenario1 was a simple case of evolutionary2 selection. In a bacterial3 population exposed to a killer4 drug, a few lucky individuals might have a genetic5 mutation6 that kept them alive. They survived to reproduce, while the rest of the population perished. In short order, the entire colony consisted only of the offspring of the drug-resistant7 founders8.

But a new study finds that just a few resistant mutants can protect large numbers of normal bacteria that would have been thought to be susceptible9 to the drug therapy. The research appears in the journal Nature.

The key seems to be that the drug-resistant mutants produce large amounts of compounds called indoles, which help bacteria tough out tough times. And the indoles from the mutants buck10 up the regular, nonresistant bacteria. The mutants themselves seem to be acting11 altruistically—their own growth is slowed by their indole production.

The finding should lead to new strategies to fight drug resistance. And it could also improve our take on evolutionary dynamics12, in systems that apparently13 experience selection pressure at both the individual and group levels.

Thanks for the minute. For Scientific American's 60-Second Science, I'm Steve Mirsky.
 


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1 scenario lZoxm     
n.剧本,脚本;概要
参考例句:
  • But the birth scenario is not completely accurate.然而分娩脚本并非完全准确的。
  • This is a totally different scenario.这是完全不同的剧本。
2 evolutionary Ctqz7m     
adj.进化的;演化的,演变的;[生]进化论的
参考例句:
  • Life has its own evolutionary process.生命有其自身的进化过程。
  • These are fascinating questions to be resolved by the evolutionary studies of plants.这些十分吸引人的问题将在研究植物进化过程中得以解决。
3 bacterial dy5z8q     
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。
4 killer rpLziK     
n.杀人者,杀人犯,杀手,屠杀者
参考例句:
  • Heart attacks have become Britain's No.1 killer disease.心脏病已成为英国的头号致命疾病。
  • The bulk of the evidence points to him as her killer.大量证据证明是他杀死她的。
5 genetic PgIxp     
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。
6 mutation t1PyM     
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。
7 resistant 7Wvxh     
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。
8 founders 863257b2606659efe292a0bf3114782c     
n.创始人( founder的名词复数 )
参考例句:
  • He was one of the founders of the university's medical faculty. 他是该大学医学院的创建人之一。 来自辞典例句
  • The founders of our religion made this a cornerstone of morality. 我们宗教的创始人把这看作是道德的基石。 来自辞典例句
9 susceptible 4rrw7     
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。
10 buck ESky8     
n.雄鹿,雄兔;v.马离地跳跃
参考例句:
  • The boy bent curiously to the skeleton of the buck.这个男孩好奇地弯下身去看鹿的骸骨。
  • The female deer attracts the buck with high-pitched sounds.雌鹿以尖声吸引雄鹿。
11 acting czRzoc     
n.演戏,行为,假装;adj.代理的,临时的,演出用的
参考例句:
  • Ignore her,she's just acting.别理她,她只是假装的。
  • During the seventies,her acting career was in eclipse.在七十年代,她的表演生涯黯然失色。
12 dynamics NuSzQq     
n.力学,动力学,动力,原动力;动态
参考例句:
  • In order to succeed,you must master complicated knowledge of dynamics.要取得胜利,你必须掌握很复杂的动力学知识。
  • Dynamics is a discipline that cannot be mastered without extensive practice.动力学是一门不做大量习题就不能掌握的学科。
13 apparently tMmyQ     
adv.显然地;表面上,似乎
参考例句:
  • An apparently blind alley leads suddenly into an open space.山穷水尽,豁然开朗。
  • He was apparently much surprised at the news.他对那个消息显然感到十分惊异。
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