SSS 2011-08-17
时间:2011-09-05 06:01:04
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(单词翻译)
This is Scientific American's 60-Second Science. I'm Steve Mirsky. Got a minute?
When a healthy rat smells a cat, it flees. But rats infected with the Toxoplasma brain
parasite1 actually follow cat odors, often presumably to their
doom2, red in tooth and claw. Now researchers have found out exactly what's going on in the rat's infected brain—it's in love. The study is in the journal Public Library of Science ONE.
That Toxo-infected rats approach cats has long been a well-known example of a parasite manipulating the behavior of its mammalian host. The protozoan needs to be in a cat's
intestine3 to reproduce. It then gets pooped out and has to find its way into another cat to continue its
fabulously4 glamorous5 lifestyle. Rats that touch the poop and then get eaten by a cat can complete the circuit.
The new research reveals that when a Toxo-infected rat smells cat urine, it has increased activity in brain regions associated with sexual attraction. Which the researchers say is "compelling evidence that Toxoplasma overwhelms the
innate6 fear response by causing, in its stead, a type of sexual attraction to the normally aversive cat odor." That's right, the rat is turned on. Before it's
permanently7 turned off.
Thanks for the minute. For Scientific American's 60-Second Science, I'm Steve Mirsky.
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