scholarly journals The Cell Envelope Stress Response of Bacillus subtilis towards Laspartomycin C

Antibiotics ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 729
Author(s):  
Angelika Diehl ◽  
Thomas M. Wood ◽  
Susanne Gebhard ◽  
Nathaniel I. Martin ◽  
Georg Fritz
Keyword(s):  
Cell Wall ◽  
Bacillus Subtilis ◽  
Stress Response ◽  
Cell Envelope ◽  
Resistance Mechanisms ◽  
Detailed Knowledge ◽  
Knock Out ◽  
Lipid Ii ◽  
Envelope Stress ◽  
The Impact

Cell wall antibiotics are important tools in our fight against Gram-positive pathogens, but many strains become increasingly resistant against existing drugs. Laspartomycin C is a novel antibiotic that targets undecaprenyl phosphate (UP), a key intermediate in the lipid II cycle of cell wall biosynthesis. While laspartomycin C has been thoroughly examined biochemically, detailed knowledge about potential resistance mechanisms in bacteria is lacking. Here, we use reporter strains to monitor the activity of central resistance modules in the Bacillus subtilis cell envelope stress response network during laspartomycin C attack and determine the impact on the resistance of these modules using knock-out strains. In contrast to the closely related UP-binding antibiotic friulimicin B, which only activates ECF σ factor-controlled stress response modules, we find that laspartomycin C additionally triggers activation of stress response systems reacting to membrane perturbation and blockage of other lipid II cycle intermediates. Interestingly, none of the studied resistance genes conferred any kind of protection against laspartomycin C. While this appears promising for therapeutic use of laspartomycin C, it raises concerns that existing cell envelope stress response networks may already be poised for spontaneous development of resistance during prolonged or repeated exposure to this new antibiotic.

scholarly journals MurJ and a novel lipid II flippase are required for cell wall biogenesis in Bacillus subtilis

2015 ◽  
Vol 112 (20) ◽  
pp. 6437-6442 ◽  
Author(s):  
Alexander J. Meeske ◽  
Lok-To Sham ◽  
Harvey Kimsey ◽  
Byoung-Mo Koo ◽  
Carol A. Gross ◽  
...  
Keyword(s):  
Cell Wall ◽  
Bacillus Subtilis ◽  
Cell Envelope ◽  
Synthetic Lethal ◽  
Bacterial Surface ◽  
E Coli ◽  
Lipid Ii ◽  
Cell Wall Biogenesis ◽  
Morphological Defects ◽  
Surface Polysaccharides

Bacterial surface polysaccharides are synthesized from lipid-linked precursors at the inner surface of the cytoplasmic membrane before being translocated across the bilayer for envelope assembly. Transport of the cell wall precursor lipid II in Escherichia coli requires the broadly conserved and essential multidrug/oligosaccharidyl-lipid/polysaccharide (MOP) exporter superfamily member MurJ. Here, we show that Bacillus subtilis cells lacking all 10 MOP superfamily members are viable with only minor morphological defects, arguing for the existence of an alternate lipid II flippase. To identify this factor, we screened for synthetic lethal partners of MOP family members using transposon sequencing. We discovered that an uncharacterized gene amj (alternate to MurJ; ydaH) and B. subtilis MurJ (murJBs; formerly ytgP) are a synthetic lethal pair. Cells defective for both Amj and MurJBs exhibit cell shape defects and lyse. Furthermore, expression of Amj or MurJBs in E. coli supports lipid II flipping and viability in the absence of E. coli MurJ. Amj is present in a subset of gram-negative and gram-positive bacteria and is the founding member of a novel family of flippases. Finally, we show that Amj is expressed under the control of the cell envelope stress-response transcription factor σM and cells lacking MurJBs increase amj transcription. These findings raise the possibility that antagonists of the canonical MurJ flippase trigger expression of an alternate translocase that can resist inhibition.

scholarly journals From Modules to Networks: a Systems-Level Analysis of the Bacitracin Stress Response in Bacillus subtilis

mSystems ◽  
2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Hannah Piepenbreier ◽  
Andre Sim ◽  
Carolin M. Kobras ◽  
Jara Radeck ◽  
Thorsten Mascher ◽  
...  
Keyword(s):  
Cell Wall ◽  
Bacillus Subtilis ◽  
Stress Response ◽  
Bacterial Resistance ◽  
Bacterial Species ◽  
Cell Wall Biosynthesis ◽  
Multiple Resistance ◽  
Resistance Response ◽  
Content Type ◽  
Lipid Ii

ABSTRACT Bacterial resistance against antibiotics often involves multiple mechanisms that are interconnected to ensure robust protection. So far, the knowledge about underlying regulatory features of those resistance networks is sparse, since they can hardly be determined by experimentation alone. Here, we present the first computational approach to elucidate the interplay between multiple resistance modules against a single antibiotic and how regulatory network structure allows the cell to respond to and compensate for perturbations of resistance. Based on the response of Bacillus subtilis toward the cell wall synthesis-inhibiting antibiotic bacitracin, we developed a mathematical model that comprehensively describes the protective effect of two well-studied resistance modules (BceAB and BcrC) on the progression of the lipid II cycle. By integrating experimental measurements of expression levels, the model accurately predicts the efficacy of bacitracin against the B. subtilis wild type as well as mutant strains lacking one or both of the resistance modules. Our study reveals that bacitracin-induced changes in the properties of the lipid II cycle itself control the interplay between the two resistance modules. In particular, variations in the concentrations of UPP, the lipid II cycle intermediate that is targeted by bacitracin, connect the effect of the BceAB transporter and the homeostatic response via BcrC to an overall resistance response. We propose that monitoring changes in pathway properties caused by a stressor allows the cell to fine-tune deployment of multiple resistance systems and may serve as a cost-beneficial strategy to control the overall response toward this stressor. IMPORTANCE Antibiotic resistance poses a major threat to global health, and systematic studies to understand the underlying resistance mechanisms are urgently needed. Although significant progress has been made in deciphering the mechanistic basis of individual resistance determinants, many bacterial species rely on the induction of a whole battery of resistance modules, and the complex regulatory networks controlling these modules in response to antibiotic stress are often poorly understood. In this work we combined experiments and theoretical modeling to decipher the resistance network of Bacillus subtilis against bacitracin, which inhibits cell wall biosynthesis in Gram-positive bacteria. We found a high level of cross-regulation between the two major resistance modules in response to bacitracin stress and quantified their effects on bacterial resistance. To rationalize our experimental data, we expanded a previously established computational model for the lipid II cycle through incorporating the quantitative action of the resistance modules. This led us to a systems-level description of the bacitracin stress response network that captures the complex interplay between resistance modules and the essential lipid II cycle of cell wall biosynthesis and accurately predicts the minimal inhibitory bacitracin concentration in all the studied mutants. With this, our study highlights how bacterial resistance emerges from an interlaced network of redundant homeostasis and stress response modules.

scholarly journals Cell Envelope Stress Response in Cell Wall-Deficient L-Forms of Bacillus subtilis

2012 ◽  
Vol 56 (11) ◽  
pp. 5907-5915 ◽  
Author(s):  
Diana Wolf ◽  
Patricia Domínguez-Cuevas ◽  
Richard A. Daniel ◽  
Thorsten Mascher
Keyword(s):  
Cell Wall ◽  
Bacillus Subtilis ◽  
Cell Envelope ◽  
Membrane Integrity ◽  
Culture Conditions ◽  
Content Type ◽  
Damage Sensing ◽  
Controlled Switching ◽  
Gene Assay ◽  
Envelope Stress

ABSTRACTL-forms are cell wall-deficient bacteria that can grow and proliferate in osmotically stabilizing media. Recently, a strain of the Gram-positive model bacteriumBacillus subtiliswas constructed that allowed controlled switching between rod-shaped wild-type cells and corresponding L-forms. Both states can be stably maintained under suitable culture conditions. Because of the absence of a cell wall, L-forms are known to be insensitive to β-lactam antibiotics, but reports on the susceptibility of L-forms to other antibiotics that interfere with membrane-anchored steps of cell wall biosynthesis are sparse, conflicting, and strongly influenced by strain background and method of L-form generation. Here we investigated the response ofB. subtilisto the presence of cell envelope antibiotics, with regard to both antibiotic resistance and the induction of the known LiaRS- and BceRS-dependent cell envelope stress biosensors. Our results show thatB. subtilisL-forms are resistant to antibiotics that interfere with the bactoprenol cycle, such as bacitracin, vancomycin, and mersacidin, but are hypersensitive to nisin and daptomycin, which both affect membrane integrity. Moreover, we established alacZ-based reporter gene assay for L-forms and provide evidence that LiaRS senses its inducers indirectly (damage sensing), while the Bce module detects its inducers directly (drug sensing).

scholarly journals From modules to networks: A systems-level analysis of the bacitracin stress response in Bacillus subtilis

2019 ◽  
Author(s):  
Hannah Piepenbreier ◽  
Andre Sim ◽  
Carolin M. Kobras ◽  
Jara Radeck ◽  
Thorsten Mascher ◽  
...  
Keyword(s):  
Cell Wall ◽  
Bacillus Subtilis ◽  
Stress Response ◽  
Bacterial Resistance ◽  
Bacterial Species ◽  
Theoretical Modelling ◽  
Cell Wall Biosynthesis ◽  
Multiple Resistance ◽  
Resistance Response ◽  
Lipid Ii

AbstractBacterial resistance against antibiotics often involves multiple mechanisms that are interconnected to ensure robust protection. So far, the knowledge about underlying regulatory features of those resistance networks is sparse, since they can hardly be determined by experimentation alone. Here, we present the first computational approach to elucidate the interplay between multiple resistance modules against a single antibiotic, and how regulatory network structure allows the cell to respond to and compensate for perturbations of resistance. Based on the response of B. subtilis towards the cell wall synthesis-inhibiting antibiotic bacitracin, we developed a mathematical model that comprehensively describes the protective effect of two well-studied resistance modules (BceAB and BcrC) on the progression of the lipid II cycle. By integrating experimental measurements of expression levels, the model accurately predicts the efficacy of bacitracin against the B. subtilis wild-type as well as mutant strains lacking one or both of the resistance modules. Our study reveals that bacitracin-induced changes in the properties of the lipid II cycle itself control the interplay between the two resistance modules. In particular, variations in the concentrations of UPP, the lipid II cycle intermediate that is targeted by bacitracin, connect the effect of the BceAB transporter and the homeostatic response via BcrC to an overall resistance response. We propose that monitoring changes in pathway properties caused by a stressor allows the cell to fine-tune deployment of multiple resistance systems and may serve as a cost-beneficial strategy to control the overall response towards this stressor.ImportanceAntibiotic resistance poses a major threat to global health and systematic studies to understand the underlying resistance mechanisms are urgently needed. Although significant progress has been made in deciphering the mechanistic basis of individual resistance determinants, many bacterial species rely on the induction of a whole battery of resistance modules, and the complex regulatory networks controlling these modules in response to antibiotic stress are often poorly understood. In this work we combine experiments and theoretical modelling to decipher the resistance network of Bacillus subtilis against bacitracin, which inhibits cell wall biosynthesis in Gram-positive bacteria. In response to bacitracin stress we find a high level of cross-regulation between the two major resistance modules and quantify their effects on bacterial resistance. To rationalize our experimental data, we expand a previously established computational model for the lipid II cycle through incorporating the quantitative action of the resistance modules. This leads us to a systems-level description of the bacitracin stress response network that captures the complex interplay between resistance modules and the essential lipid II cycle of cell wall biosynthesis and accurately predicts the minimal inhibitory bacitracin concentration in all the studied mutants. With this, our study highlights how bacterial resistance emerges from an interlaced network of redundant homeostasis and stress response modules.

scholarly journals Proteomic Response of Bacillus subtilis to Lantibiotics Reflects Differences in Interaction with the Cytoplasmic Membrane

2012 ◽  
Vol 56 (11) ◽  
pp. 5749-5757 ◽  
Author(s):  
Michaela Wenzel ◽  
Bastian Kohl ◽  
Daniela Münch ◽  
Nadja Raatschen ◽  
H. Bauke Albada ◽  
...  
Keyword(s):  
Cell Wall ◽  
Bacillus Subtilis ◽  
Pore Formation ◽  
Cytoplasmic Membrane ◽  
Cell Wall Biosynthesis ◽  
Membrane Pore ◽  
Content Type ◽  
Lipid Ii ◽  
Proteomic Response ◽  
The Impact

ABSTRACTMersacidin, gallidermin, and nisin are lantibiotics, antimicrobial peptides containing lanthionine. They show potent antibacterial activity. All three interfere with cell wall biosynthesis by binding lipid II, but they display different levels of interaction with the cytoplasmic membrane. On one end of the spectrum, mersacidin interferes with cell wall biosynthesis by binding lipid II without integrating into bacterial membranes. On the other end of the spectrum, nisin readily integrates into membranes, where it forms large pores. It destroys the membrane potential and causes leakage of nutrients and ions. Gallidermin, in an intermediate position, also readily integrates into membranes. However, pore formation occurs only in some bacteria and depends on membrane composition. In this study, we investigated the impact of nisin, gallidermin, and mersacidin on cell wall integrity, membrane pore formation, and membrane depolarization inBacillus subtilis. The impact of the lantibiotics on the cell envelope was correlated to the proteomic response they elicit inB. subtilis. By drawing on a proteomic response library, including other envelope-targeting antibiotics such as bacitracin, vancomycin, gramicidin S, or valinomycin, YtrE could be identified as the most reliable marker protein for interfering with membrane-bound steps of cell wall biosynthesis. NadE and PspA were identified as markers for antibiotics interacting with the cytoplasmic membrane.

scholarly journals The LiaFSR System Regulates the Cell Envelope Stress Response in Streptococcus mutans

2009 ◽  
Vol 191 (9) ◽  
pp. 2973-2984 ◽  
Author(s):  
Prashanth Suntharalingam ◽  
M. D. Senadheera ◽  
Richard W. Mair ◽  
Céline M. Lévesque ◽  
Dennis G. Cvitkovitch
Keyword(s):  
Stress Response ◽  
Streptococcus Mutans ◽  
Cell Envelope ◽  
Membrane Integrity ◽  
Transcriptional Analysis ◽  
Dependent Manner ◽  
Bacterial Survival ◽  
Concentration Dependent Manner ◽  
Lipid Ii ◽  
Envelope Stress

ABSTRACT Maintaining cell envelope integrity is critical for bacterial survival, including bacteria living in a complex and dynamic environment such as the human oral cavity. Streptococcus mutans, a major etiological agent of dental caries, uses two-component signal transduction systems (TCSTSs) to monitor and respond to various environmental stimuli. Previous studies have shown that the LiaSR TCSTS in S. mutans regulates virulence traits such as acid tolerance and biofilm formation. Although not examined in streptococci, homologs of LiaSR are widely disseminated in Firmicutes and function as part of the cell envelope stress response network. We describe here liaSR and its upstream liaF gene in the cell envelope stress tolerance of S. mutans strain UA159. Transcriptional analysis established liaSR as part of the pentacistronic liaFSR-ppiB-pnpB operon. A survey of cell envelope antimicrobials revealed that mutants deficient in one or all of the liaFSR genes were susceptible to Lipid II cycle interfering antibiotics and to chemicals that perturbed the cell membrane integrity. These compounds induced liaR transcription in a concentration-dependent manner. Notably, under bacitracin stress conditions, the LiaFSR signaling system was shown to induce transcription of several genes involved in membrane protein synthesis, peptidoglycan biosynthesis, envelope chaperone/proteases, and transcriptional regulators. In the absence of an inducer such as bacitracin, LiaF repressed LiaR-regulated expression, whereas supplementing cultures with bacitracin resulted in derepression of liaSR. While LiaF appears to be an integral component of the LiaSR signaling cascade, taken collectively, we report a novel role for LiaFSR in sensing cell envelope stress and preserving envelope integrity in S. mutans.

scholarly journals An Antibiotic-Inducible Cell Wall-Associated Protein That Protects Bacillus subtilis from Autolysis

2007 ◽  
Vol 189 (13) ◽  
pp. 4671-4680 ◽  
Author(s):  
Letal I. Salzberg ◽  
John D. Helmann
Keyword(s):  
Cell Wall ◽  
Bacillus Subtilis ◽  
Cell Envelope ◽  
Sequence Similarity ◽  
Envelope Stress ◽  
Class B ◽  
Dependent Cell ◽  
A Cell ◽  
Close Relatives ◽  
Minimal Region

ABSTRACT In Bacillus subtilis, antibiotics that impair cell wall synthesis induce a characteristic stress response including the σW and σM regulons and the previously uncharacterized yoeB gene. Here we demonstrate that YoeB is a cell wall-associated protein with weak sequence similarity to a noncatalytic domain of class B penicillin-binding proteins. A yoeB-null mutant exhibits an increased rate of autolysis in response to cell wall-targeting antibiotics or nutrient depletion. This phenotype does not appear to be correlated with gross alterations in peptidoglycan structure or levels of autolysins. Promoter dissection experiments define a minimal region necessary for antibiotic-mediated induction of yoeB, and this region is highly conserved preceding yoeB homologs in close relatives of B. subtilis. These results support a model in which induction of YoeB in response to cell envelope stress decreases the activity of autolysins and thereby reduces the rate of antibiotic-dependent cell death.

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