Christian Long

Bonnie Bassler: How Bacteria Communicate

In TED Talks on April 23, 2010 at 9:58 pm

Reflection by HERSH T.

Original TED page w/ speaker bio, links, comments, etc:

Bonnie Bassler:  How Bacteria Communicate

The oldest and simplest living thing is bacteria. If, as Mrs. Bassler says, we compare the amount of cells in our body to the number of bacteria on or in our body at all times we can multiply the number of cells (about a trillion) by ten, which would then give us the number of bacterial cells. So these bacteria cells are much more prevalent than we can even conceivably think about. And Mrs. Bassler makes a clever pun that we are not just humans, we are about 90% bacterial.

Of course the bacteria keep us alive.

The bacteria do not just ride on or in our bodies; they actually perform many functions such as ingesting our food and protecting us through the immune system which actually keep us alive. However, that knowledge has just come up recently, before our time and during our time as well, we can see that bacteria are blamed for just about everything that goes wrong in our current day society. However, often in this day and age we actually make assumptions which then make our basis of knowledge shaky. So, Mrs. Bassler asks the fundamental question of how something so small could affect us so profoundly.

A bacterium is so small that it requires a microscope to see and yet it still affects us in such incredibly profound ways.

Mrs. Bassler conducted a lab in which they studied the bacteria which make light similar to that of fireflies. However, alone, these bacteria make no light whatsoever. They remain black and in the case of a disease would remain innocuous. The discovery was that when the bacteria had a certain amount of bacterium around it, all the bacteria would turn the light on simultaneously.

How is this possible for such simple single-celled organisms?

It appears that these bacteria use something called quorum sensing. Quorum sensing is when the bacteria are releasing a certain chemical messenger, at all times, and alone it does nothing, but when all the bacteria are releasing it together than it has an effect. This is what happens in diseases. If the bacteria is alone then releasing a toxin would have absolutely no effect because of the magnitude of the human body, but when all the bacteria are together than when they release the toxin it has a much more potent effect on the human body.

And, delving further into the subject, we can see that the bacteria actually have more than one sense for these chemical messengers. They have a specific one which only works among the bacteria of the same nature and type; however, all bacteria have a general messenger that can communicate across the domain of bacteria.

The magnificent thing about this is we can potentially disrupt these molecules which could stop the release of toxins preemptively.

When we take into account the fact that the bacteria releases a toxin when it is surrounded by bacteria then what if we actually created a chemical messenger that could block the sensors on the membrane of the bacteria and so it would not release the toxin no matter what and simply be washed out?

Once again bacteria have been around for hundreds of millions of years and humans are only barely old enough to affect them. However, as Mrs. Bassler says, bacteria could have actually created the rules for multicellular organisms. We as humans are simply fancy bacteria and so we must always give our predecessors due respect. Thank you bacteria for allowing me to analyze why you do what you do.

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