SSS 2008-09-04

（单词翻译）

This is Scientific American's 60-Second Science. I'm Cynthia Graber. This will just take a minute.

Conditions such as mad cow disease are caused by abnormally shaped proteins, called prions. Prions spread by causing other, normal proteins to misfold and adopt the abnormal shape—no genetic¹ material like DNA² is involved. Prion diseases affect the brains of a number of mammals, including humans. Although humans can get mad cow from beef, these unusual diseases rarely jump between species. Still, scientists say new forms of prion diseases have arisen lately, and there’s concern that they could hop³ to humans. So researchers want to understand the species barrier better.

A study published in the September 4th issue of the journal Cell investigates that issue. Scientists from Texas, Spain and Chile took normal hamster proteins and mixed them with misfolded mouse ones.  And the mouse prions were able to change the hamster proteins into a new kind of prion that infected both healthy hamsters and mice. The test tube is obviously an unnatural⁴ situation, but it shows that prions can leap the species barrier without the aid of any other infectious agent. Scientists hope to learn more about how this process works so they can keep prions in their place—away from humans.

Thanks for the minute for Scientific American's 60-Second Science. I'm Cynthia Graber .