E coli gets a bad reputation. Most people think of food poisoning or lettuce recalls when they think of E. coli, but not all strains are harmful! Actually most strains are very beneficial and we need some strains of E. coli to keep our microbiome fully functioning.

The spindles that are coming coming out of the E. coli drawn here are a mix of pili and flagella. These help the bacteria move through their surroundings usually towards a food source or away from harmful sources (or toxins) in a process known as chemotaxis.

E. coli also produces and secretes a variety of different signals. Some signals, known as quorum sensing molecules, tell bacteria the number of surrounding bacteria. Other signals turn on certain genes thus causing the bacteria to express or repress those genes. When a gene is expressed, the production of the protein corresponding to that gene increases, likewise if the gene is repressed, the corresponding protein sees a decrease in production.