Bacterial biofilm in a hot spring in Northern Nevada
For a long time, microbiologists thought that bacteria cells acted as individual entities and did not communicate with one another. We now understand that nearly all cells communicate- whether its the stomach cells within our own body or the mass of cells within the hot spring biofilm above.
Biofilms are dense aggregates of billions of cells that stick together to form a mass that we can actually see with our own eyes. One of the most interesting features of biofilms is that they are generally composed of a variety of different kinds of bacteria, working together as a community. In much the way our communities differentiate labor to benefit the whole (garbage collection, food production and trasnport, etc.), these aggregates of bacteria form fluid channels for transport of waste and nutrients and rely on communication to perform these tasks.
Instead of using verbal communication, bacteria cells talk to each other using signaling molecules that are released into the environment. Different bactieral species use different signaling molecules to communicate. Within biofilms, interspecies (between two different species) communication can be very important. Communication allows indivudal bacteria cells to regulate gene expression by sensing cell density, the presence of "intruders" and the availability of nutrients.
