Cell division in walled Bacillus subtilis and cell wall-lacking Acholeplasma laidlawii

Bacterial resistance to the antibiotics is an increasing worldwide health problem, and the inhibition of the bacterial divisome, especially by targeting the central cell division mediator FtsZ, has been regarded as a promising strategy for antibiotic attack. Therefore, the knowledge of detailed bacterial cell division process, contribute to the discovery of novel antibiotic targets. Cell division is initiated by polymerization of the tubulin homologue FtsZ into ring-like structure at mid-cell, and afterwards, the late division proteins involving in synthesis of septal wall are recruited. In this thesis, I found in Gram-positive bacterium Bacillus subtilis, the extra free SepF interferes the recruitment of late division proteins, and polymerized FtsZ, cannot alone recruit late cell division proteins, without the assistance of FtsA and EzrA. Besides, I also found many metabolic and stress pathways, in Bacillus subtilis, linked to (Fts)Z-ring assembly by transcriptome analysis. For a long time, the “peptidoglycan-centric” model, whereby the membrane is pushed inwards by synthesis of septal cell wall, is regarded as the main force to trigger the cell division, this thesis also investigated FtsZ-centric model in cell wall-lacking bacterium Acholeplasma ladialwii, and identified cell division can also occur by FtsZ-triggered cell membrane constriction, and in this case, cell propagates by budding instead of traditional binary fission.