Question: How do you know bacteria are communicating?

Katie Fala answered on 12 Nov 2019:

Great question JackScienceFan13! I am studying a couple of specific chemical signals that bacteria use to communicate with another (and then change their behaviour based on the size of the population and the other types of bacteria that might happen to be nearby). These signals can be detected by growing the bacteria that I am testing close to another bacteria called an ‘indicator’. One of these indicators is called Chromobacterium violaceum, as the name suggests it make a purple pigment when there are high levels of the chemical signal.

There is another indicator I use to detect a different chemical signal, but instead it produces bio-luminescence (light!) when it detects the chemical (my profile pic on here has an example of a petri dish with the bio-luminescent bacteria in the background)

We can also use some techniques involving chromatography to identify the type and shape of the signals being produced.

Finally, we can use molecular techniques to look at the DNA and RNA of the bacteria to see what genes get expressed when the levels of the chemical signals are very high or very low.

Hope that answered your question, let me know if you have any more!