How do we do it

The kind of experiments we do either measure directly the properties of living bacteria (in vivo experiments) or measure the properties of purified molecules such as the complexes formed between proteins and DNA (in vitro experiments). Once we have purified the protein and DNA that interest us we can study the formation of the interactions between them. This will help us find out which part, or sequence, of the DNA is recognized by a protein and how environmental variables such as temperature can affect this interaction. In live bacteria we can measure the amount of gene expression, how fast and when a given protein is produced. To do this we use a fluorescent protein, GFP, that is produced by the bacterium. In the picture on the right you can see a photo of a petri dish with bacterial colonies on it. Some of the colonies contain bacteria with a bit of fluorescent protein, some with a lot more, you can measure the fluorescence by exposing the bacteria to blue light.We can do this kind of measurement in a whole population of bacteria, or one bacterium at a time (an example in this movie). In our laboratory we do experiments, but we also work with physicists and mathematicians who make models, or theoretical experiments (in silico experiments).