The general stress response of Bacillus subtilis

The soil bacterium Bacillus subtilis responds to fluctuating conditions in its environment with a wide variety of stress responses. Apart from a series of specific responses and a series of large-scale developmental changes, B. subtilis also has a general stress response (GSR). The GSR is activated in response to a wide variety of stresses, which include ‘environmental stresses’, such as salt shock and ethanol shock, and ‘energy stresses’, such as starvation of various nutrients. Both types of stresses activate separate, but converging, signal transduction pathways. The pathway that is activated by environmental stresses has a large protein complex, called the stressosome, as its most upstream component known to date. Many questions remain open regarding the stressosome. However, it is clear that the stressosome can be activated by blue light via the blue-light photoreceptor protein YtvA. The primary aim of the work presented in this thesis was to increase our understanding of the mechanisms that govern stressosome function. We have primarily used blue light to study the stressosome, as blue light is its only known direct input signal