All cells need to sense and respond to different stresses in their local environment in order to survive and grow, and bacteria are certainly no exception. The model soil bacterium Bacillus subtilis senses different stresses using discrete pathways that converge to elicit a general protective response.
However, how bacterial cells respond to stresses over time has been difficult to determine, as growing cells in a flask or on a microscope slide crowd their locale, thus inducing their own stress.
By combining microfluidic technology with the genetic tractability of B. subtilis, researchers in the Losick lab have overcome previous experimental obstacles and observed how single bacterial cells respond to the onset and presence of different stresses over tens of generations. B. subtilis uses distinct signal transduction pathways to respond to environmental and energy stresses, which were induced with ethanol and nucleotide synthesis inhibitors, respectively.
Their results show that bacteria can mount vastly different responses, ranging from the sharp and transient to the slow and sustained, depending on the type of stress and the complement of response proteins present in the cell. These findings open the door to a new molecular-level understanding of how bacteria mount specific responses and how different response profiles are optimized for surviving different types of stress.