Like flatmates, bacteria which live in the same space can have complicated and ever-changing relationships. These can depend on the species of bacteria, other substances in the environment, and many other things. Species can live peacefully alongside each other, but sometimes conditions change and cause one to take over. With bacteria living inside us, one particular species becoming too abundant can cause disease. A recently developed method can help us understand changing relationships between bacterial species. Characteristics of a patch (colony) of bacteria, such as size and shape, are automatically measured. The colonies shown here are bacteria normally found in the human lung. Scientists found that adding benzo[a]pyrene, a chemical found in cigarettes, caused one species of bacteria to inhibit the growth of another, whereas normally it would enhance it. This can help us understand how we change the balance of the tiny ecosystems inside us.
Written by Esther Redhouse White
BPoD stands for Biomedical Picture of the Day. Managed by the MRC London Institute of Medical Sciences (the new name for the MRC Clinical Sciences Centre) the website aims to engage everyone, young and old, in the wonders of biomedicine. Images are kindly provided for inclusion on this website through the generosity of scientists across the globe.