scholarly journals Loss of Bacterial Cell Pole Stabilization in Caulobacter crescentus Sensitizes to Outer Membrane Stress and Peptidoglycan-Directed Antibiotics

2019 ◽  
Author(s):  
Simon-Ulysse Vallet ◽  
Lykke Haastrup Hansen ◽  
Freja Cecillie Bistrup ◽  
Julien Bortoli Chapalay ◽  
Marc Chambon ◽  
...  
Keyword(s):  
Cell Wall ◽  
Caulobacter Crescentus ◽  
Cell Envelope ◽  
Wall Stress ◽  
Two Component System ◽  
Component System ◽  
Division Plane ◽  
Cell Wall Stress ◽  
Two Component ◽  
Weak Points

AbstractRod-shaped bacteria frequently localise proteins to one or both cell poles in order to regulate processes such as chromosome replication or polar organelle development. However, the role of such polar factors in responses to extracellular stimuli has been generally unexplored. We employed chemical-genetic screening to probe the interaction between one such factor from Caulobacter crescentus, TipN, and extracellular stress and found that TipN is required for normal tolerance of cell envelope-directed antibiotics, including vancomycin that does not normally inhibit growth of Gram-negative bacteria. Forward genetic screening for suppressors of vancomycin sensitivity in the absence of TipN revealed the TonB-dependent receptor ChvT as the mediator of vancomycin tolerance. Loss of ChvT improved resistance to vancomycin and cefixime in the otherwise sensitive ΔtipN strain. The activity of the two-component system regulating ChvT (ChvIG) was increased in ΔtipN cells relative to wild type under some, but not all, cell wall stress conditions that this strain was sensitised to, in particular cefixime and detergent exposure. Together, these results indicate that the ChvIG two-component system has been co-opted as a sensor of cell wall stress and that TipN can influence cell envelope stability and ChvIG-mediated signaling in addition to its roles in intracellular development.Author summaryMaintenance of an intact cell envelope is essential for free-living bacteria to survive harsh conditions they may encounter in their environment. In the case of rod-shaped bacteria, the poles of the cell are potential weak points in the cell envelope due to the high curvature of the layers and the need to break and re-form parts of the cell envelope at the division plane in order to form new poles as the cells replicate and divide. We have found that TipN, a factor required for correct division and cell pole development in the rod-shaped bacterium, Caulobacter crescentus, is also needed for maintaining normal levels of resistance to cell wall-targeting antibiotics such as vancomycin and cefixime, which interfere with peptidoglycan synthesis. We also identified an outer membrane receptor, ChvT, that was responsible for allowing vancomycin access to the cells and found that the two-component system that negatively regulates ChvT production was activated by various kinds of cell wall stress. Presence or absence of TipN influenced how active this system was in the presence of cefixime or of the membrane-disrupting detergent sodium deoxycholate. Since TipN is normally located at the poles of the cell and at the division plane just before cells complete division, our results suggest that it is involved in stabilisation of these weak points of the cell envelope as well as its other roles inside the cell.

scholarly journals Loss of Bacterial Cell Pole Stabilization in Caulobacter crescentus Sensitizes to Outer Membrane Stress and Peptidoglycan-Directed Antibiotics

mBio ◽  
2020 ◽  
Vol 11 (3) ◽  
Author(s):  
Simon-Ulysse Vallet ◽  
Lykke Haastrup Hansen ◽  
Freja Cecillie Bistrup ◽  
Signe Aagaard Laursen ◽  
Julien Bortoli Chapalay ◽  
...  
Keyword(s):  
Cell Wall ◽  
Caulobacter Crescentus ◽  
Cell Envelope ◽  
Wall Stress ◽  
Two Component System ◽  
Content Type ◽  
Division Plane ◽  
Cell Wall Stress ◽  
Two Component ◽  
Weak Points

ABSTRACT Rod-shaped bacteria frequently localize proteins to one or both cell poles in order to regulate processes such as chromosome replication or polar organelle development. However, the roles of polar factors in responses to extracellular stimuli have been generally unexplored. We employed chemical-genetic screening to probe the interaction between one such factor from Caulobacter crescentus, TipN, and extracellular stress and found that TipN is required for normal resistance of cell envelope-directed antibiotics, including vancomycin which does not normally inhibit growth of Gram-negative bacteria. Forward genetic screening for suppressors of vancomycin sensitivity in the absence of TipN revealed the TonB-dependent receptor ChvT as the mediator of vancomycin sensitivity. Loss of ChvT improved resistance to vancomycin and cefixime in the otherwise sensitive ΔtipN strain. The activity of the two-component system regulating ChvT (ChvIG) was increased in ΔtipN cells relative to the wild type under some, but not all, cell wall stress conditions that this strain was sensitized to, in particular cefixime and detergent exposure. Together, these results indicate that TipN contributes to cell envelope stress resistance in addition to its roles in intracellular development, and its loss influences signaling through the ChvIG two-component system which has been co-opted as a sensor of cell wall stress in Caulobacter. IMPORTANCE Maintenance of an intact cell envelope is essential for free-living bacteria to protect themselves against their environment. In the case of rod-shaped bacteria, the poles of the cell are potential weak points in the cell envelope due to the high curvature of the layers and the need to break and reform the cell envelope at the division plane as the cells divide. We have found that TipN, a factor required for correct division and cell pole development in Caulobacter crescentus, is also needed for maintaining normal levels of resistance to cell wall-targeting antibiotics such as vancomycin and cefixime, which interfere with peptidoglycan synthesis. Since TipN is normally located at the poles of the cell and at the division plane just before cells complete division, our results suggest that it is involved in stabilization of these weak points of the cell envelope as well as its other roles inside the cell.

scholarly journals Requirement of the CroRS Two-Component System for Resistance to Cell Wall-Targeting Antimicrobials in Enterococcus faecium

2017 ◽  
Vol 61 (5) ◽  
Author(s):  
Stephanie L. Kellogg ◽  
Jaime L. Little ◽  
Jessica S. Hoff ◽  
Christopher J. Kristich
Keyword(s):  
Cell Wall ◽  
Enterococcus Faecium ◽  
Wall Stress ◽  
Signaling System ◽  
Beta Lactam ◽  
Two Component System ◽  
Component System ◽  
Content Type ◽  
Cell Wall Stress ◽  
Two Component

ABSTRACT Enterococci are serious opportunistic pathogens that are resistant to many cell wall-targeting antibiotics. The CroRS two-component signaling system responds to antibiotic-mediated cell wall stress and is critical for resistance to cell wall-targeting antibiotics in Enterococcus faecalis. Here, we identify and characterize an orthologous two-component system found in Enterococcus faecium that is functionally equivalent to the CroRS system of E. faecalis. Deletion of croRS in E. faecium resulted in marked susceptibility to cell wall-targeting agents including cephalosporins and bacitracin, as well as moderate susceptibility to ampicillin and vancomycin. As in E. faecalis, exposure to bacitracin and vancomycin stimulates signaling through the CroRS system in E. faecium. Moreover, the CroRS system is critical in E. faecium for enhanced beta-lactam resistance mediated by overexpression of Pbp5. Expression of a Pbp5 variant that confers enhanced beta-lactam resistance cannot overcome the requirement for CroRS function. Thus, the CroRS system is a conserved signaling system that responds to cell wall stress to promote intrinsic resistance to important cell wall-targeting antibiotics in clinically relevant enterococci.

scholarly journals Cell envelope gene expression in phosphate-limited Bacillus subtilis cells

Microbiology ◽  
2011 ◽  
Vol 157 (9) ◽  
pp. 2470-2484 ◽  
Author(s):  
Eric Botella ◽  
Sebastian Hübner ◽  
Karsten Hokamp ◽  
Annette Hansen ◽  
Paola Bisicchia ◽  
...  
Keyword(s):  
Cell Wall ◽  
Bacillus Subtilis ◽  
Cell Envelope ◽  
Expression Profiles ◽  
Phosphate Limitation ◽  
Envelope Gene ◽  
Two Component System ◽  
Cell Wall Metabolism ◽  
Component System ◽  
Two Component

The high phosphate content of Bacillus subtilis cell walls dictates that cell wall metabolism is an important feature of the PhoPR-mediated phosphate limitation response. Here we report the expression profiles of cell-envelope-associated and PhoPR regulon genes, determined by live cell array and transcriptome analysis, in exponentially growing and phosphate-limited B. subtilis cells. Control by the WalRK two-component system confers a unique expression profile and high level of promoter activity on the genes of its regulon with yocH and cwlO expression differing both qualitatively and quantitatively from all other autolysin-encoding genes examined. The activity of the PhoPR two-component system is restricted to the phosphate-limited state, being rapidly induced in response to the cognate stimulus, and can be sustained for an extended phosphate limitation period. Constituent promoters of the PhoPR regulon show heterogeneous induction profiles and very high promoter activities. Phosphate-limited cells also show elevated expression of the actin-like protein MreBH and reduced expression of the WapA cell wall protein and WprA cell wall protease indicating that cell wall metabolism in this state is distinct from that of exponentially growing and stationary-phase cells. The PhoPR response is very rapidly deactivated upon removal of the phosphate limitation stimulus with concomitant increased expression of cell wall metabolic genes. Moreover expression of genes encoding enzymes involved in sulphur metabolism is significantly altered in the phosphate-limited state with distinct perturbations being observed in wild-type 168 and AH024 (ΔphoPR) cells.

scholarly journals The Two-Component System CesRK Controls the Transcriptional Induction of Cell Envelope-Related Genes in Listeria monocytogenes in Response to Cell Wall-Acting Antibiotics

2008 ◽  
Vol 190 (13) ◽  
pp. 4772-4776 ◽  
Author(s):  
Sanne Gottschalk ◽  
Iver Bygebjerg-Hove ◽  
Mette Bonde ◽  
Pia Kiil Nielsen ◽  
Thanh Ha Nguyen ◽  
...  
Keyword(s):  
Cell Wall ◽  
Listeria Monocytogenes ◽  
Cell Envelope ◽  
Two Component System ◽  
Component System ◽  
Two Component ◽  
Transcriptional Induction ◽  
Damaging Effects

ABSTRACT The two-component system CesRK of Listeria monocytogenes responds to cell wall-acting antibiotics. We show here that CesRK controls the transcription of several cell envelope-related genes. The CesRK-dependent induction of these genes may be viewed as an attempt by L. monocytogenes to protect itself against the damaging effects of cell wall-acting antibiotics.

scholarly journals Antibiotic-Inducible Promoter Regulated by the Cell Envelope Stress-Sensing Two-Component System LiaRS of Bacillus subtilis

2004 ◽  
Vol 48 (8) ◽  
pp. 2888-2896 ◽  
Author(s):  
Thorsten Mascher ◽  
Sara L. Zimmer ◽  
Terry-Ann Smith ◽  
John D. Helmann
Keyword(s):  
Cell Wall ◽  
Bacillus Subtilis ◽  
Cytoplasmic Membrane ◽  
Cell Envelope ◽  
Inducible Promoter ◽  
Two Component System ◽  
Component System ◽  
Lipid Ii ◽  
Two Component ◽  
Stress Sensing

ABSTRACT Soil bacteria are among the most prodigious producers of antibiotics. The Bacillus subtilis LiaRS (formerly YvqCE) two-component system is one of several antibiotic-sensing systems that coordinate the genetic response to cell wall-active antibiotics. Upon the addition of vancomycin or bacitracin, LiaRS autoregulates the liaIHGFSR operon. We have characterized the promoter of the lia operon and defined the cis-acting sequences necessary for antibiotic-inducible gene expression. A survey for compounds that act as inducers of the lia promoter revealed that it responds strongly to a subset of cell wall-active antibiotics that interfere with the lipid II cycle in the cytoplasmic membrane (bacitracin, nisin, ramoplanin, and vancomycin). Chemicals that perturb the cytoplasmic membrane, such as organic solvents, are also weak inducers. Thus, the reporter derived from P liaI (the liaI promoter) provides a tool for the detection and classification of antimicrobial compounds.

scholarly journals Reciprocal Regulation of Resistance-Nodulation-Division Efflux Systems and the Cpx Two-Component System in Vibrio cholerae

2014 ◽  
Vol 82 (7) ◽  
pp. 2980-2991 ◽  
Author(s):  
Dawn L. Taylor ◽  
X. Renee Bina ◽  
Leyla Slamti ◽  
Matthew K. Waldor ◽  
James E. Bina
Keyword(s):  
Antimicrobial Resistance ◽  
Vibrio Cholerae ◽  
Cell Envelope ◽  
Two Component System ◽  
Reciprocal Regulation ◽  
Component System ◽  
Content Type ◽  
Expression Of Genes ◽  
Two Component ◽  
Resistance Nodulation Division

ABSTRACTThe Cpx two-component regulatory system has been shown inEscherichia colito alleviate stress caused by misfolded cell envelope proteins. TheVibrio choleraeCpx system was previously found to respond to cues distinct from those in theE. colisystem, suggesting that this system fulfills a different physiological role in the cholera pathogen. Here, we used microarrays to identify genes that were regulated by theV. choleraeCpx system. Our observations suggest that the activation of theV. choleraeCpx system does not induce expression of genes involved in the mitigation of stress generated by misfolded cell envelope proteins but promotes expression of genes involved in antimicrobial resistance. In particular, activation of the Cpx system induced expression of the genes encoding the VexAB and VexGH resistance-nodulation-division (RND) efflux systems and their cognate outer membrane pore protein TolC. The promoters for these loci contained putative CpxR consensus binding sites, and ectopiccpxRexpression activated transcription from the promoters for the RND efflux systems. CpxR was not required for intrinsic antimicrobial resistance, but CpxR activation enhanced resistance to antimicrobial substrates of VexAB and VexGH. Mutations that inactivated VexAB or VexGH efflux activity resulted in the activation of the Cpx response, suggesting thatvexABandvexGHand thecpxP-cpxRAsystem are reciprocally regulated. We speculate that the reciprocal regulation of theV. choleraeRND efflux systems and the Cpx two-component system is mediated by the intracellular accumulation of an endogenously produced metabolic by-product that is normally extruded from the cell by the RND efflux systems.

scholarly journals Two-Component System Cross-Regulation Integrates Bacillus anthracis Response to Heme and Cell Envelope Stress

2014 ◽  
Vol 10 (3) ◽  
pp. e1004044 ◽  
Author(s):  
Laura A. Mike ◽  
Jacob E. Choby ◽  
Paul R. Brinkman ◽  
Lorenzo Q. Olive ◽  
Brendan F. Dutter ◽  
...  
Keyword(s):  
Bacillus Anthracis ◽  
Cell Envelope ◽  
Two Component System ◽  
Component System ◽  
Envelope Stress ◽  
Two Component

scholarly journals Mutational Analyses of Open Reading Frames within thevraSROperon and Their Roles in the Cell Wall Stress Response ofStaphylococcus aureus

2011 ◽  
Vol 55 (4) ◽  
pp. 1391-1402 ◽  
Author(s):  
N. McCallum ◽  
P. Stutzmann Meier ◽  
R. Heusser ◽  
B. Berger-Bächi
Keyword(s):  
Signal Transduction ◽  
Cell Wall ◽  
Cell Envelope ◽  
Wall Stress ◽  
Integral Membrane Protein ◽  
Luciferase Reporter ◽  
Wild Type ◽  
Luciferase Reporter Gene ◽  
Cell Wall Stress ◽  
Type Strains

ABSTRACTThe exposure ofStaphylococcus aureusto a broad range of cell wall-damaging agents triggers the induction of a cell wall stress stimulon (CWSS) controlled by the VraSR two-component system. ThevraSRgenes form part of the four-cistron autoregulatory operonorf1-yvqF-vraS-vraR. The markerless inactivation of each of the genes within this operon revealed thatorf1played no observable role in CWSS induction and had no influence on resistance phenotypes for any of the cell envelope stress-inducing agents tested. The remaining three genes were all essential for the induction of the CWSS, and mutants showed various degrees of increased susceptibility to cell wall-active antibiotics. Therefore, the role of YvqF inS. aureusappears to be opposite that in other Gram-positive bacteria, where YvqF homologs have all been shown to inhibit signal transduction. This role, as an activator rather than repressor of signal transduction, corresponds well with resistance phenotypes of ΔYvqF mutants, which were similar to those of ΔVraR mutants in which CWSS induction also was completely abolished. Resistance profiles of ΔVraS mutants differed phenotypically from those of ΔYvqF and ΔVraR mutants on many non-ß-lactam antibiotics. ΔVraS mutants still became more susceptible than wild-type strains at low antibiotic concentrations, but they retained larger subpopulations that were able to grow on higher antibiotic concentrations than ΔYvqF and ΔVraR mutants. Subpopulations of ΔVraS mutants could grow on even higher glycopeptide concentrations than wild-type strains. The expression of a highly sensitive CWSS-luciferase reporter gene fusion was up to 2.6-fold higher in a ΔVraS than a ΔVraR mutant, which could be linked to differences in their respective antibiotic resistance phenotypes. Bacterial two-hybrid analysis indicated that the integral membrane protein YvqF interacted directly with VraS but not VraR, suggesting that it plays an essential role in sensing the as-yet unknown trigger of CWSS induction.

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