Responses of Bacillus subtilis to Hypotonic Challenges: Physiological Contributions of Mechanosensitive Channels to Cellular Survival

• DOI: 10.1128/aem.01573-07
• Publication Date: 2008-03-01T02:37:03Z
• Authors: Tamara Hoffmann; Clara Boiangiu; Susanne Moses; Erhard Bremer
• Keywords: Osmotic concentration; Osmotic shock; Osmotic pressure; Osmoregulation

ABSTRACT Mechanosensitive channels are thought to function as safety valves for the release of cytoplasmic solutes from cells that have manage a rapid transition high- low-osmolarity environments. Subsequent an osmotic down-shock grown at high osmolarity, Bacillus subtilis rapidly releases previously accumulated compatible solute glycine betaine in accordance with degree downshift. Database searches suggest B. possesses one copy gene mechanosensitive channel large conductance ( mscL ) and three copies genes encoding proteins putatively form small yhdY , yfkC ykuT ). Detailed mutational analysis all potential channel-forming revealed quadruple mutant has no growth disadvantage high-osmolarity media comparison wild type. Osmotic experiments demonstrated MscL is principal system strains disruption exhibited severe survival defect upon down-shock. We also detected minor contribution SigB-controlled putative MscS-type protein YkuT cellular mutant. Taken together, our data both MscS types play pivotal roles managing hyper- hypo-osmotic