glow-in-the-dark bacterium that lives in the ocean -- all bacteria have systems like this. 住在大海中、会在黑暗中发光的细菌，而是所有的细菌都有类似的系统。

　　So now what we understand is that all bacteria can talk to each other. 由此，我们发现所有细菌都是可以彼此交谈的。

　　They make chemical words, they recognize those words, 它们制造化学文字，同时也能够辨认这些文字，

　　and they turn on group behaviors that are only successful when all of the cells participate in unison. 然后表现只有当所有细胞齐心协力才能成功的集体行为。

　　We have a fancy name for this: we call it quorum sensing. 我们为这种行为取了一个新潮的名字，称作：聚量感应。

　　They vote with these chemical votes, the vote gets counted, and then everybody responds to the vote. 就象用化学物质投票，再对票量加以统计，然后所有细胞都要服从最后的投票结果。

　　And what's important for today's talk is that we know that there are hundreds of behaviors that bacteria carry out in these collective fashions. 今天演讲最重要的一点是，我们已经知道细菌有数百种以上的这种集体行为。

　　But the one that's probably the most important to you is virulence. 其中对大家来说，最关心的应该还是细菌的致病性。

　　So it's not like a couple bacteria get in you and they start secreting some toxins -- you're enormous, that would have no effect on you. You're huge. 并不是说少量细菌进入你体内后就马上开始分泌毒素。相对它们来说，你是个庞然大物，少量细菌对你不会有任何的影响。

　　What they do, we now understand, is they get in you, they wait, they start growing, they count themselves with these little molecules, 我们发现，它们是先进入你的体内，然后等待，开始不断复制增长，它们由统计小分子的数目来估计自身的实力，

　　and they recognize when they have the right cell number that if all of the bacteria launch their virulence attack together, 当确定有足够的细胞数后，所有细菌一起发动致病攻击，

　　they are going to be successful at overcoming an enormous host. 这样它们就能成功攻陷巨大的宿主。

　　So bacteria always control pathogenicity with quorum sensing. And so that's how it works. 细菌总是以聚量感应来控制其致病性。这就是它们运作的原理。