I have been playing recently with simple, computer-controlled systems for growing bacteria in the presence of antibiotics. The picture shows a “morbidostat” that I have build (see here for the first system of this type). I want to use it to track how bacteria evolve resistance to drugs.
The system consists of a small tube (20ml) holding the bacteria, a magnetic stirrer, three peristaltic pumps, an infrared LED and a phototransistor to measure turbidity of the culture, and a few other things, all inside a transparent incubator set to 37C.
The plot shows how the population of bacteria (E. coli) responds to the increasing concentration of the drug (ciprofloxacin). The drug is kept at a level that stresses the bacteria and forces them to evolve.