Prions (one example: mad cow) Cross Species Barrier In Lab

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[scientific American]Conditions such as mad cow disease are caused by abnormally shapedproteins, called prions. Prions spread by causing other, normalproteins to misfold and adopt the abnormal shape—no genetic materiallike DNA is involved. Prion diseases affect the brains of a number ofmammals, including humans. Although humans can get mad cow from beef,these unusual diseases rarely jump between species. Still, scientistssay new forms of prion diseases have arisen lately, and there'sconcern that they could hop to humans. So researchers want tounderstand the species barrier better.A study published in the September 4th issue of the journal Cellinvestigates that issue. Scientists from Texas, Spain and Chile tooknormal hamster proteins and mixed them with misfolded mouse ones. ...-- full

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