Thursday, August 20, 2009

Alienness



Lovecraft selected "vermin" as subjects of his horror knowing they would instinctively bring emotions of revulsion to his readers.

We don't consider rats, frogs, and squid as vermin now. It's "biodiversity". However, we're not immune to shock and revulsion, either. Read on...

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This is a electron microscope image of a virus that is harmless to us but deadly to bacteria. The little appendages lock on to the relatively cyclopean bacteria while the shaft penetrates the cell membrane injecting the small package of a piece of spaghetti-like DNA). Once into the cell necleus it reprograms the cell to literally dismantle itself and make copies of the virus!



On a Kappa Alpha Tau tangent, National Geographic a few years back published an article. The parasite Toxoplasma gondii uses a remarkable trick to spread from rodents to cats: It alters the brains of infected rats and mice so that they become attracted to—rather than repelled by—the scent of their predators. Rodents infected with the parasitic protozoa are drawn to the smell of cat urine, apparently having lost their otherwise natural aversion to the scent. The parasite can only sexually reproduce in the feline gut, so it's advantageous for it to get from a rodent into a cat—if necessary, by helping the latter eat the former.


In rodents, "brain circuits for many behaviors overlap with the brain circuits responsible for fear," said Ajai Vyas of Stanford University, who led the new study. "One would thus assume that if something messes up fear of cat pee, it will also mess up a variety of related behaviors." But Vyas's experiments showed that not to be the case.


In fact, his test demonstrated just how precise and efficient the mind-bending parasite is. While manipulating rodents' innate fear of felines, T. gondii leaves other behaviors intact. Toxoplasma-infected mice and rats retained most typical rodent phobias, including fears of dog odors, strange-smelling foods, and open spaces. Infected rodents also didn't appear to be sick. Only the animals' response to cats was abnormal: Uninfected rodents avoided an area of a room that researchers had scented with cat urine. But infected rodents actually seemed drawn to the smell. "Toxoplasma affects fear of cat odors with almost surgical precision," Vyas concluded. "A large number of other behaviors remain intact."

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