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August 2, 2003
Small Talk
Turns out, bacteria can communicate. Are they
talking behind our backs?
by Scott C. Anderson
 A
few years ago, Bonnie Bassler discovered something fishy about the
bacteria she was studying. Actually, they were already pretty fishy,
since these diminutive critters lived in the bodies of deep-sea
fish, squid and jellyfish. Weirder still, these bacteria could glow
a most beguiling moonlight blue.
This was great for the fish, who could
use them as a gaudy glowing lure, and pretty cool for the squid,
who could use the glow to become virtually invisible in the moonlit
sea. But it was a conundrum for Dr. Bassler, who couldn't figure
out why the bacteria insisted on waiting for a crowd to show up
before starting to get a glow on. It seemed to imply that the bacteria
could somehow talk to each other in order to agree upon when to
start glowing. But everyone knew that bacteria couldn't possibly
communicate. They were, after all, only bacteria…
But after much hard work, Dr. Bassler (now at Princeton)
finally found a chemical she called a signaling molecule. As the
bacteria multiplied they would secrete this signaling molecule and
at a certain threshold they would be fairly swimming in the stuff.
At that point, they would all start to glow in unison. Dr. Bassler
had discovered the language of bacteria. Because it's triggered
by a specific density of bacteria, it's known as "quorum sensing."
Every year since, new types of bacteria have been added to the growing
roster of microscopic chatterboxes. Many of them can speak two languages,
letting them hold conversations with different species.
 So
what does that mean for you, other than providing a good reason
to toss away any seafood that glows in the dark? Well, some of the
bacteria being researched are about as nasty as they can be, including
cholera, TB and the plague - and they're all talking behind your
back. About what? Well, unfortunately, they're plotting to kill
or at least maim you: by observing their version of radio silence,
they can infiltrate your body without alarming the guardian cells
of the immune system. Then, as soon as their numbers are unstoppable,
their attack is launched. The clinical term for this is "Yikes!"
Dr. Bassler's discovery may help researchers find
a completely new way to stop these decidedly unfriendly bacteria.
Preliminary work indicates that when these gregarious bacteria are
chemically gagged, they can't issue the call to arms and are thus
rendered impotent. That would be a nice breakthrough, seeing as
how we're entering a scary new era of bacterial resistance - and
we're running out of solutions.
Dr. Bassler's work may just save your life. Not bad
for paying attention to small talk.
Dr. Bassler responds:
"Its wonderful! It's the most straightforward
description of QS [quorum sensing] I've ever read! I'll send it
to my father who, no matter how many times I go through it, cannot
seem to understand what I work on!"
-- Bonnie Bassler
For more information on Dr. Bassler's
work, check out these sites:
Princeton
Stanford
Wired
Copyright © 2000-2004 by Scott Anderson
For reprint rights, email the author:
Scott_Anderson@ScienceForPeople.com
Here are some other suggested readings
in bacteriology:
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