Secretion stress, ROS stress and gene fitness in Bacillus subtilis

In this thesis, different aspects of Bacillus subtilis have been studied. We implemented RNA-seq and zymologic assays to study the secretion stress in B. subtilis and identified that the induction of CtsR-regulated chaperones improves Xylanase production. Using similar method, we discovered that the inactivation of the conserved protease LonA increases the production of xylanase and amylase in B. subtilis. We implemented Tn-seq to study the gene fitness contribution and we found that teichoic acid modifications are required for intercellular competition in B. subtilis. We used genetic screening in combination with fluorescent microscopy to study the bactericidal mechanism of membrane depolarization antibiotics and proved that membrane depolarization kills dormant B. subtilis cells by generating a lethal dose of ROS. We applied fluorescence-activated cell sorting (FACS) with flow cytometry to investigate the bimodal differentiation and showed that different resource allocation is a reason causing bimodal motility in B. subtilis.