Bacteria that talk to each other

April 9, 2009 | By | 7 Replies More

Bonnie Bassler, who teaches molecular biology at Princeton, explains that bacteria don’t just grow and divide, grow and divide. They speak to each other and with other species of bacteria through their chemicals.

Bassler studies how bacteria use chemical signals to act as coordinated social units. In this delightful TED talk, Bassler discusses how her research group has studied the manner in which bacteria talk to each other.  They make chemical “words” to enable group activities (such as triggering the timing for effective virulence attacks), sensing each other through their “quorum-sensing molecules.”  They can also sense the difference between themselves and other bacteria.

Note that each of us is 99% bacterial. Our human body consists of about one trillion of “our own” cells, but ten trillion bacteria.  We have about 30,000 of “our own” genes, but we carry about 100 times more bacterial DNA than human DNA.  Bacteria live as “mutualists” with us. They help us digest our food, make our vitamins, protects us from other pathogens and help us survive in numerous other ways.

Rather than using antibiotics to kill bacteria (which inevitably selects for more virulent strains), Bassler suggests that a better understanding of the communications schemes used by bacteria is allowing scientists to develop potent new medicines.

This is an upbeat and informative talk regarding a most ancient form of life.


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Category: Communication, Evolution, Human animals, nature, Networking, Science

About the Author ()

Erich Vieth is an attorney focusing on consumer law litigation and appellate practice. He is also a working musician and a writer, having founded Dangerous Intersection in 2006. Erich lives in the Shaw Neighborhood of St. Louis, Missouri, where he lives half-time with his two extraordinary daughters.

Comments (7)

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  1. Great talk, I learned stuff I didn't know before. I wonder what the reli-fundies will have to say about it ;-).

  2. TonyC says:

    If you want to hear some more about Quorum Sensing (and get weirded out too) you should read "Blood Music" by Greg Bear. I was intersted before I read that – I got very intereseted after I read it. (and a lot of the science in the book is actually true- which is even cooler!)

  3. Dan Klarmann says:

    Quibble: One part human cells to ten parts bacteria is 10/11 bacteria = 91%. A significant fraction of human cells are larger than bacteria, like nerve and muscle cells measuring up to a meter in length. So the fraction drops significantly if measured by by mass or volume.

    But we are outnumbered inside our skin.

  4. Ebonmuse says:

    In fairness to humans, I do have to point out that our cells are much bigger than bacterial cells. (We eukaryotes have many organelles and lots of other internal structure that prokaryotic cells don't.) To get an idea of the scale here, consider that the mitochondria, the energy-producing organelles of eukaryotes, are descended from prokaryotes that entered into symbiosis with us. A typical human cell can contain anywhere from several hundred to several thousand mitochondria.

    Those ten to fifteen trillion bacteria that live in the average human body (most in the gut) would just about fill a 10-ounce soup can.

  5. Hank says:

    I loved this talk. Bonnie's very engaging and enthusiastic and I learned a bunch of cool new stuff about our tiny cousins – stuff my med student wife didn't even know and which I got to relay to her (it's not often I get to do that).

    I heartily recommend browsing the TED site to anyone. Perfect viewing for a rainy day.

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