My Favorite TED Talk

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    And it’s hard to choose just one, but it would have to be Bonnie Bassler’s talk on bacterial communication, which just went online.

    I had dinner with Bonnie before her talk and was captivated. So much so that I changed seats to talk with her instead of Paul Allen, Bezos, and some other very interesting folks around the table.

    There are 10x as many bacterial cells as human cells in and on your body, and 100x as many bacterial genes as human genes. And you depend on them for survival.

    “At best you are 10% human, but closer to 1%, depending on which metrics you like.”

    It reminded me of Craig Venter’s observation that the bacteria in each of our lungs is genetically unique, evolving in real time in an adaptive dance with our immune system.

    How can some bacteria make us sick? At a fraction of the size of a human cell, “bacteria are too small to have an impact on the environment if they simply act as individuals.”

    All bacteria can talk to each other. They make chemical words, they recognize those words, and they turn on group behaviors that are only successful when all of the cells participate in unison.”

    Bacteria always control pathogenicity with quorum sensing.”

    They wait until they are concentrated enough before they launch an attack on their host; otherwise they would be wasting energy when sub-threshold.

    And to prevent local hot spots emerging in isolation from their more distant peers, each bacteria has a positive feedback loop, dumping more signaling chemicals into the bath once they cross a threshold (this way, the entire population can switch modes in unison, from growth mode to attack mode for example).

    Each bacteria has two separate signaling pathways. One receptor is exquisitely unique to each species, and one general to all bacteria (“bacterial Esperanto”). Bacteria can distinguish self from other and can determine their absolute concentration and their concentration relative to other bacteria.

    “This is the invention of multi-cellularity. We think bacteria made the rules for how multi-cellular organization works.”

    Jam the receptor. Instead of killing the bacteria, which would engendering evolutionary resistance, “what if we could do ‘behavior modifications’ so they can’t talk and don’t know to launch virulence.”

    At dinner, I suggested that artificially induced group behaviors may also be interesting in biofilms used for water purification and other non-medical applications.

    I was also reminded of my first course on neural networks (Rummelhardt, PDP). After simulating a number of neuronal circuits, early research concluded that the neuron needs a sigmoid function — some non-linear tipping point in its response curve — for learning to occur. The positive feedback loop in bacterial quorum sensing is just such a sigmoid, and may provide clues to the early development of cellular signaling, initially among nearest neighbors in pre-Cambrian blobs, and then across differentiated body plans with the long-span neuronal cells. I’m not thinking of evolutionary subsumption or endobiosis, but a resonant developmental homology in primitive signaling systems.

    “When you learn new things about natural science, whenever you read something miraculous, it was done by a child. Everyone on my research team is between 20 and 30 years old. They are the engine that drives scientific discovery in this country.”

    You can see why this was my favorite talk. =)

    Christie13, fstar, tifotter, and 11 other people added this photo to their favorites.

    1. Jonathan Ruff 73 months ago | reply

      Fun stuff! I have to agree with you on your seating choice. Although maybe you should have dragged Bezos along with you - what he's up to in the cloud is a lot more interesting than anything Allen has done in the last 15 or so years.

    2. Doug_Dirac_Delta 73 months ago | reply

      I'm a physics guy, but I find that utterly fascinating.

    3. Todd Huffman 73 months ago | reply

      Agreed. I watched her talk a few days ago and it was stunningly good.

      The first time I read about biofilms I couldn't get over the complexity of behavior coordinated across so many species. It screams 'organism'.

      Biofilms are multi-cellular organisms... just ones that underwent cell differentiation thousands of years ago.

    4. Tomi Tapio 73 months ago | reply

      Ah, the mysteries of the unseen world. Thanks J-man!

    5. drona 73 months ago | reply

      Steve, reading your blog is like getting a sigmoid shock for my neurons, there's always something new in there to learn! :)

      Great talk -- thanks for the pointer!

    6. courtneymccolgan 73 months ago | reply

      We knew you were only 10% human Steve. Good to know the rest of us aren't that far behind...

    7. fotogail 73 months ago | reply

      I stumbled on that video and loved it.. very cool to read more backstory.

      (I had questions in the other direction, not about stopping bacterial action, but about learning more about how they are singing to one another as refelcted in one of the world's most complex ancient beverages, the aged Gueuze or Straight Lambic, in which dozens of species of 'bugs' go through successive blooms to make a complex sour beer after several years. Very exicting talk while thinking of that context, too.)

    8. Victor1 73 months ago | reply

      Wow, how fascinating and how informative...guess I'll keep on eating garlic and the wheat grass and green juices since they are anti-bacterial and keep the 'gangs from forming' by consensus which bring us down. thanks Steve.

    9. drona 72 months ago | reply

      After listening to this talk, I met with somebody at the Carnegie Institution over by that university on the side of 280, and they said that Bonnie's work would not have been possible without advances made in computational biology in recent years. Especially the part about developing new types of bad-bacteria-killers (medicines) have been made possible because of advances in gene sequencing. The ability to disrupt communications between bacteria is quite powerful indeed. These types of techniques have also been used for the elimination of pests in agriculture.

      Much work is also done at Carnegie on phototropes.

    10. david.orban 72 months ago | reply

      Understanding, and speaking the 'language' of bacteria is a necessary first step if we want to interfere in their communications.

      Blood Music, en.wikipedia.org/wiki/Blood_Music, by Greg Bear is one of the most fascinating fictional stories to be based on microbial communication (in that case not between bacteria, but of lymphocytes), brought to its rightly fantastically farout consequences.

    11. Loops666 72 months ago | reply

      Wow, I've been out of school almost too long to understand this! Interesting stuff...and nice colors in the picture!

    12. jurvetson 72 months ago | reply

      exciting stuff. drona - yeah, the frontier of bio is coupled to Moore's Law.

      The bacterial communication extends beyond nearest neighbors with nanowires. Here is a nice summary:

      "Nanowire pili are essential in biofilm formation and are also required for cell aggregation. This is an interesting idea because forming communities and accumulating a high enough cell density allows for higher rates of electron transfer. Allowing for such an extensive network of microbial nanowires even allows for electrical transfer across long distances.

      Spiders weave, ants build highways, and now it seems that bacteria have managed to network themselves better than Microsoft."


    13. mikescottnz 71 months ago | reply

      Hi, I'm an admin for a group called A Picture for a GMO Free World, and we'd love to have this added to the group!

      So long as its all not talked , as if , it's all reduced to genetic leggo blocks which seems to be the commerciial or Venters messianic approach?

    14. booledozer 8 months ago | reply

      This image was uploaded here --
      commons.wikimedia.org/wiki/File:Bonnie_Bassler_TED_talk_i...
      Thanks for using a CC liscense that allows re-use!

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