在线英语听力室_免费在线英语听力学习网站

(单词翻译:双击或拖选)

 

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 bugs¹—like the kind that cause gum disease. So says a study in the journal Infection and Immunity². 

 

Researchers gave a complete dental cleaning to 30 volunteers, half of whom were regular smokers³. Then, as bacteria moved back in, they took plague samples and sequenced the DNA⁴ in those scrapings. And they found that non-smokers tended to have stable bacterial⁵ communities, dominated by a few benign⁶ 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

点击收听单词发音