Structural and functional studies on the transcriptional regulation of flagellar motility and biofilm formation

Devid Mrusek, Bange, Gert (Prof. Dr.), Chemie
Part 1: Numerical regulation in the monotrichous bacterium Shewanella putrefaciens Microorganisms have the ability to adapt to changing environmental conditinos. This has enabled them to colonize virtually nearly every niche on the planet Earth. Key to this ability is bacterial motility, which allows bacteria to move away from unfavourable conditions and to move towards favourable conditions. In connection with a sensory system, which detects chemical cues and other stimuli, bacteria can move
more » ... wards nutrients. Bacterial motility is largely enabled by flagella. The biogenesis of a flagellum is a very costly process, which is for this reason highly regulated. In the monotrichous bacterium Shewanella putrefaciens, FlhF and FlhG are responsible for maintaining number and location of the single polar flagellum. In the course of this work, it could be shown that FlhG limits the number of flagella to one by directly interacting with the master transcriptional regulator of the flagellum, FlrA. Furthermore, FlhG is implicated in assembly of the cytosolic face of the flagellum, the C-Ring. The transcriptional control via FlrA as well as the C-Ring assembly via FliM occur through the same binding site on FlhG. This highlights the central role of FlhG and shows that FlhG integrates the two processes to regulate flagellar number. Taken together, these observations represent an important step towards a complete conceptual description of flagellar biogenesis. Thereby, these results also form the basis for further research. Part 2: Transcriptional regulation of biofilms is mediated by RemA, which interacts with DNA in a histone-like manner Instead of a motile lifestyle, bacteria can also establish a multicellular, sessile lifestyle in the form of biofilms. In biofilms, bacterial cells establish a division of labour and establish an increased resistance against antibiotics and environmental hazardous conditions. This is mediated by the secretion of extracellular proteins and other biological molecules. The protein RemA is centra [...]
doi:10.17192/z2019.0114 fatcat:u42zbgaifnavfgdg24tds3cmhy