Bacterial differentiation is an important process in stress survival, improving the chances of a bacterial colony surviving the stressor.
Spore formation, sporulation, is a process that can occur during stress, producing dormant spores that are highly resistant to heat, radiation, and nutrient absence. This increases the chance the bacteria will be able to restart growth when growth conditions become more favourable. As sporulation is a very energy intensive process that cannot easily be reversed, it begins when the stress reaches the point of no return. A fruiting body may be formed, allowing altruistic cells to form a mound of lysed cells to provide energy to the cells that will form the spores.
The c-signal is essential in forming fruiting bodies. When CsgA, the protein allowing this contact-dependent signalling to occur, is knocked out, fruiting bodies are no longer able to form in Myxococcus.
Peripheral rods are also formed under cell stress, branching out from the fruiting body. These dormant cells are able to be ‘reactivated’ on detecting the presence of nutrients and minerals. This ability to detect and respond to changes in the environment is important in restarting growth of the bacteria.
Spores can remain viable for hundreds of years.