The top 10 life-forms living on Lady Gaga (and you)
Posted by Rahmi Lale | Filed under Science
Guest Blog, Scientific American Blog Network by Rob Dunn
Alongside the filaments of our fungi live bacteria. The bacteria on our feet consume the amino acid leucine found in sweat. It is these amino-acid-eaters that cause feet to stink. In eating leucine, these creatures excrete a gaseous perfume (isovaleric acid) that is instantly recognizable as it rises up from under the table. The stinking bacteria on most of our feet are Staphylococcus epidermidis, but those of us with especially stinky feet may also host another species of bacteria, Bacillus subtilis, which, despite its name, stinks with a ferocious lack of subtlety.
Several studies have mapped the distribution of particular species of bacteria on our bodies, but historically such studies considered only bacteria that could be grown in the lab. As of the last five years, we now know that most of the bacteria on our bodies cannot be grown in the lab. When new genetic approaches are used to “see” what is living on us, they find tens or even hundreds of kinds of microbes not noted before, many of them previously unknown to science or known to science only by the the code of their genes (map image from Bibell and Lovell 1976). Nearly two hundred kinds of bacteria have been found on human forearms alone, where it was thought that there were fewer than a dozen.
I hesitate to even tell you that you may have brain parasites. In these bad economic times, no one needs something else to worry about. Yet, they could be in there, wedged deeply between your ears. I am talking about Toxoplasma gondii, a parasite of cats. Toxoplasma gondii is able to reproduce only when it is inside the gut of a cat. It needs to find a cat, really bad. Usually it does so by finding something that cats eat, such as rats. Inside rats, it makes its way to the brain where it causes the rats to be attracted to the smell of cat pee, which they would ordinarily avoid (who wouldn’t). A rat that follows cat pee is likely to find a cat and when it does to end up in the cat’s gut, where the Toxoplasma gondii can finally mate.
Lessons can be learned from the life that coats us, inside and out. We might learn tolerance of others, or at least of the others on us. We might learn to appreciate how poorly known the world still is, even the world of our own bodies
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