It may be hard to believe, but this sea of shiny, donut-shaped colonies are Pseudomonas aeruginosa colonies. These Pseudomonas colonies have a genetic mutation that causes many of the bacteria’s genes to be shut off. The donut-shape of these colonies may indicate a two-step growth phase where the younger cells on the outside edge of the colony grow towards more nutrients while the older cells in the center are stuck in a nutrient-depleted location.
Contributed by Ian Hill, a fifth year graduate student in the Biological and Biomedical Sciences program at Harvard University, and our Featured Artist for January and February, 2018. To meet Ian and see more of his art, click here.