Turning on the Bio-Lights
Ambience: Waves
A quorum is a minimum number of individuals necessary to agree to an endeavor. This holds true for people – and bacteria. I’m Jim Metzner and this is the Pulse of the Planet.
Heidelberg: The light production in these bacteria are under a system called quorum sensing control.
John Heidelberg is the Associate Director of the Wrigley Institute for Environmental Studies and a Principal Investigator for Earthwatch. The bacteria he’s speaking of are bioluminescent they live on creatures like Anglerfish or a species of squid, and they can glow in the dark when then they sense that they have a quorum, which in their case is a lot of bacteria!
Heidelburg: Quorum sensing is that if you think about the light that can be produced by a single bacterium, it’s not going to be bright enough for anybody to see, any organisms. So really what has to happen is you have to get a huge number, billions of cells together in a very small area, in order for there to be enough cells producing light for that light to be visible.
The bacteria have a system called quorum sensing control that says that, “I’m not gonna turn on these genes until I know there are this billion of my brethren around me.” The system works by a cell producing a molecule that can diffuse, can move outside of the cell freely. And so if you’re there by yourself and you’re producing this, you’re throwing this cell out into the water and it’s just flowing away from you. So it gets diluted out, but as more and more cells grow, all of those other cells also producing this molecule are throwing them out of their cells, and they’re diffusing into your cell. So, you start to build up this molecule inside of you. Once that molecule builds up to an appropriate level, that means that there are enough cells around you producing this molecule, that if we turn on our light system, it’ll be visible to animals.
I’m Jim Metzner and this is the Pulse of the Planet.