SSS 2012-02-21
时间：2018-12-24 作者：英语课 分类：Scientific American(二)月
英语课
This is Scientific American 60 second Science, I am Christopher Intagliata, got a minute?
It's no secret cigarettes can yellow your teeth. But tobacco smoke has another, unseen effect. It can wipe out the healthy bacteria in your mouth, leaving the field open for pathogenic bugs 1—like the kind that cause gum disease. So says a study in the journal Infection and Immunity 2.
Researchers gave a complete dental cleaning to 30 volunteers, half of whom were regular smokers 3. Then, as bacteria moved back in, they took plague samples and sequenced the DNA 4 in those scrapings. And they found that non-smokers tended to have stable bacterial 5 communities, dominated by a few benign 6 species. That's good, because a healthy biofilm educates your immune system—preventing unnecessary attacks and inflammation—and it keeps bad bacteria at bay.
Smokers, on the other hand, had wildly transient populations, with species moving in and out—which opened up real estate for the bad bugs. Smokers also had higher levels of inflammation, which can destroy friendly bacteria, too. The researchers aren't sure yet why smoking
1 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
- 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》
2 immunity
n.优惠；免除；豁免，豁免权
- The law gives public schools immunity from taxation.法律免除公立学校的纳税义务。
- He claims diplomatic immunity to avoid being arrested.他要求外交豁免以便避免被捕。
3 smokers
吸烟者( smoker的名词复数 )
- Many smokers who are chemically addicted to nicotine cannot cut down easily. 许多有尼古丁瘾的抽烟人不容易把烟戒掉。
- Chain smokers don't care about the dangers of smoking. 烟鬼似乎不在乎吸烟带来的种种危害。
4 DNA
(缩)deoxyribonucleic acid 脱氧核糖核酸
- 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。