Democracy Among the Microbes

In light of today's historical events, I decided to NOT talk about our new president. I figure there's a lot of other bloggers out there that can do a way better job of it than I can! So instead, I shall talk about democracy of a different kind: quorum sensing.

In a nutshell, quorum sensing is how certain bacterial communities determine when to do something once they reach a particular population density. What they "do" depends on bacterial species and where that particular species is growing.

For example, see that picture of glowing green bacteria? These bacteria, found in squid eyes, are called Vibrio fischeri. At populations of less than 10^11, (that's a 1 with 11 zeros behind it), they don't glow. However, when they reach populations of over 100,000,000,000 cells, we get glow!!!

Bacteria also use quorum sensing to secret toxins that stop the growth of other bacteria. -Or to orchestrate an effort to suddenly overthrow a host's immune system and give it a bad case of pneumonia! Muhuhahahaaa!

In any case, quorum sensing allows bacteria to not only sense how many other bacterial cells are out there, but it also directs a large population of bacteria into doing something that, in small numbers, would be impossible to do.

How is it done? Err... that would be a topic for another day.

Quorum sensing - committees that actually work!