Our long term goal is to define the regulatory pathways that respond to cell envelope stress using Bacillus subtilis as a model system. Exposure of bacteria to antibiotics that interfere with cell wall synthesis or membrane function activates several large regulons coordinated by extracytoplasmic function (ECF) sigma factors and two-component regulatory systems (TCS). These regulons include genes involved in the inactivation or efflux of antibiotics, in remodeling of the cell surface to increase resistance, and in the production of antibiotics. We will pursue three aims directed at understanding the global stress responses elicited by cell envelope stress. First, we will characterize a bacteriocin produced by sporulating B. subtilis cells that selectively kills non-sporulating cells of the same species. This bacteriocin will be structurally characterized, its spectrum and mode of activity defined, and the role of the Sigma-W regulon in defending against bacteriocin activity will be explored. We will also characterize a Sigma-W dependent bacteriocin that is produced in response to antibiotic exposure. Second, we will investigate a TCS that responds to a variety of cell wall active antibiotics that interfere with lipid II function or cycling. This TCS, LiaRS, has an unusual sensor kinase that is representative of a family of intramembrane-sensing kinases and may interact with the LiaF membrane proten. We will explore the nature of signal-sensing by the LiaRS system and define the LiaR regulon. Third, we will use transcriptional profiling to define the stress responses elicited by exposure to antibiotics. This work will compare the stimulons associated with antibiotics with well defined mechanisms of action and closely related structural variants with altered function. In addition, the stimulons elicited by co-culture of B. subtilis with other antibiotic producing bacteria, including Bacilli and Streptomycetes, will be explored. Finally, we will identify and characterize novel antibiotic resistance mechanisms focusing on genes that are strongly induced as part of the cell envelope stress responses. ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
2R01GM047446-13
Application #
6876325
Study Section
Microbial Physiology and Genetics Subcommittee 2 (MBC)
Program Officer
Anderson, James J
Project Start
1992-05-01
Project End
2008-12-31
Budget Start
2005-01-01
Budget End
2005-12-31
Support Year
13
Fiscal Year
2005
Total Cost
$467,968
Indirect Cost
Name
Cornell University
Department
Microbiology/Immun/Virology
Type
Schools of Earth Sciences/Natur
DUNS #
872612445
City
Ithaca
State
NY
Country
United States
Zip Code
14850
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Xue, Xiaowei; Davis, Maria C; Steeves, Thomas et al. (2016) Characterization of a protein-protein interaction within the SigO-RsoA two-subunit ? factor: the ?70 region 2.3-like segment of RsoA mediates interaction with SigO. Microbiology 162:1857-1869
Helmann, John D (2016) Bacillus subtilis extracytoplasmic function (ECF) sigma factors and defense of the cell envelope. Curr Opin Microbiol 30:122-132
Zhao, Heng; Sun, Yingjie; Peters, Jason M et al. (2016) Depletion of Undecaprenyl Pyrophosphate Phosphatases Disrupts Cell Envelope Biogenesis in Bacillus subtilis. J Bacteriol 198:2925-2935
Schirner, Kathrin; Eun, Ye-Jin; Dion, Mike et al. (2015) Lipid-linked cell wall precursors regulate membrane association of bacterial actin MreB. Nat Chem Biol 11:38-45
Helmann, John D (2015) Molecular scribes in the spotlight: Methods for illuminating Bacterial and Archaeal transcription. Methods 86:1-3
Helmann, John D (2015) Chemical proteomics reveals a second family of cyclic-di-AMP hydrolases. Proc Natl Acad Sci U S A 112:1921-2
Gaballa, Ahmed; Chi, Bui Khanh; Roberts, Alexandra A et al. (2014) Redox regulation in Bacillus subtilis: The bacilliredoxins BrxA(YphP) and BrxB(YqiW) function in de-bacillithiolation of S-bacillithiolated OhrR and MetE. Antioxid Redox Signal 21:357-67
Lee, Yong Heon; Helmann, John D (2014) Mutations in the primary sigma factor ?A and termination factor rho that reduce susceptibility to cell wall antibiotics. J Bacteriol 196:3700-11
Kingston, Anthony W; Zhao, Heng; Cook, Gregory M et al. (2014) Accumulation of heptaprenyl diphosphate sensitizes Bacillus subtilis to bacitracin: implications for the mechanism of resistance mediated by the BceAB transporter. Mol Microbiol 93:37-49

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