New insights into the regulatory networks of Bacillus subtilis controlling general stress response and osmo adaptation The soil living Gram positive bacterium Bacillus subtilis is frequently exposed to a wide variety of stress and starvation conditions in its natural environment. In order to survive under these environmental and energy stresses the bacterium acquired a general stress response mechanism mediated by the alternative sigma factor SigB. A wide variety of stress conditions such as environmental stress conditions like ethanol stress heat stress oxidative stress osmotic stress or limitation of glucose oxygen phosphate etc.; and low temperature growth induce this SigB dependent general stress response. Though much is known about the mechanisms of activation of this general stress response the conditions that induce the SigB regulon and its general functions the definition of the structure of the SigB regulon is not completely clear. The SigB dependent general stress regulon has previously been characterized by proteomic approaches as well as DNA array based expression studies. Genome wide expression studies performed by Price Petersohn and Helmann defined the SigB regulon containing well above 100 target genes however the overlapping list of target genes contains only 67 members. The differences between these studies probably result from the different strains growth conditions array platforms and experimental setups used in these studies. The first part of this work presents a targeted microarray analysis which was performed to gain a better understanding ... Heubacillus Microarray general stress response SigB tiling array expression analysis osmotic stress