科学美国人60秒 SSS 唾液蛋白可能抑制肠道无序状态（在线收听）

Saliva Protein Might Inhibit Intestinal Anarchy

唾液蛋白可能抑制肠道无序状态

Every day, you produce one to two liters of spit. It kick-starts digestion and helps you swallow. And it helps prevent bacterial infection in your mouth.

每天，你会产生一到两公升的唾液。唾液能促进消化，帮助吞咽，也有助于防止口腔细菌感染。

"But that still seemed like a lot of energy put into something if it's only going to do that small task." Esther Bullitt, a biophysicist at the Boston University School of Medicine. "And we wondered whether there was something else it was doing as well, if maybe it had a farther reach than just preventing infections in the mouth."

“但是，即使只能做这么小的工作，却似乎还是有很多精力投入的。”波士顿大学医学院生物物理学家Esther Bullitt表示。“我们想知道，唾液是否还有其他用途，比如说，它不仅仅可以防止口腔感染的功能。”

So she and her team looked farther down the pipes—at whether certain proteins in spit might also disrupt the work of bad bugs in the gut. They grew cells taken from the small intestine of a 51-year-old woman. They also grew a batch of pathogenic E. coli bacteria, the kind that cause traveler's diarrhea. The E. coli have hairlike extensions, called pili, that grab onto the intestinal cells. But fewer of the E. coli were able to successfully attach to the intestinal cells when a particular saliva protein, called histatin-5, was hanging around.

因此，她和研究小组进一步研究了唾液中某些蛋白质是否会干扰肠道内的有害细菌的工作。他们从一名51岁的妇女的小肠中提取细胞。他并培养了一批致病性大肠杆菌，这种细菌会导致旅行者腹泻。大肠杆菌有毛发状的突触，叫做pili，这种突触附着肠道细胞。但是，当一种叫做histatin-5的特殊唾液蛋白悬浮在肠道中时，大肠杆菌的数量就减少了。

You can think of the E. coli like pirate ships, trying to dock at a port. What the histatin-5 does is stop the pirate ships, the bad bugs, from using their ropes—the pili—to dock. "If you can't bind, then you can't start an infection. So no adhesion, no infection, no disease."

你可以想象一下大肠杆菌像海盗船一样，试图在一个港口停靠。histatin-5所做的就是阻止海盗船，那些坏的虫子，从使用它们的绳索套住的码头。“如果不能结合，那么就不能开始无法开始感染。”所以没有粘附，没有感染，没有疾病。

The study is in The Journal of Infectious Diseases.

该项研究结果发表在《传染病杂志》上。

The salivary protein can be chemically synthesized; stored as a powder; and dissolved in water. And presumably, the resulting liquid is safe. "You know that your body tolerates it, because you swallow one to two liters of it every day." No word yet on whether it might someday be available at the drugstore. But the good news is: you're already swallowing some right now.

可以化学合成唾液蛋白质; 以粉末形式储存; 并溶于水。 据推测，这种液体是安全的。“你知道我们身体能与它共存，你每天吞下一升到两升的唾液啊。” 目前还没有关于它是否有在药店可用的消息。但好消息是：你现在已经在吞咽一些了。