scholarly journals Transcriptional Signature following Inhibition of Early-Stage Cell Wall Biosynthesis in Staphylococcus aureus

2009 ◽  
Vol 53 (4) ◽  
pp. 1701-1704 ◽  
Author(s):  
A. J. O'Neill ◽  
J. A. Lindsay ◽  
K. Gould ◽  
J. Hinds ◽  
I. Chopra
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Microarray Analysis ◽  
Dna Microarray ◽  
Late Stage ◽  
Mode Of Action ◽  
Early Stage ◽  
Transcriptional Response ◽  
Cell Wall Biosynthesis ◽  
Transcriptional Signature

ABSTRACT To facilitate mode of action studies on antibacterial inhibitors of early-stage cell wall biosynthesis (CWB), we determined the transcriptional response of Staphylococcus aureus to depletion/inhibition of enzymes in this pathway by DNA microarray analysis. We identified a transcriptional signature distinct from that previously observed following exposure to inhibitors of late-stage CWB.

scholarly journals Oritavancin Exhibits Dual Mode of Action to Inhibit Cell-Wall Biosynthesis in Staphylococcus aureus

2008 ◽  
Vol 377 (1) ◽  
pp. 281-293 ◽  
Author(s):  
Sung Joon Kim ◽  
Lynette Cegelski ◽  
Dirk Stueber ◽  
Manmilan Singh ◽  
Evelyne Dietrich ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Mode Of Action ◽  
Cell Wall Biosynthesis ◽  
Dual Mode

scholarly journals Insights into the Mode of Action of Chitosan as an Antibacterial Compound

2008 ◽  
Vol 74 (12) ◽  
pp. 3764-3773 ◽  
Author(s):  
Dina Raafat ◽  
Kristine von Bargen ◽  
Albert Haas ◽  
Hans-Georg Sahl
Keyword(s):  
Antimicrobial Activity ◽  
Cell Wall ◽  
Cell Membrane ◽  
Mode Of Action ◽  
Membrane Lipids ◽  
Expression Profiles ◽  
Transcriptional Response ◽  
Response Analysis ◽  
Sequence Of Events ◽  
Wide Range

ABSTRACT Chitosan is a polysaccharide biopolymer that combines a unique set of versatile physicochemical and biological characteristics which allow for a wide range of applications. Although its antimicrobial activity is well documented, its mode of action has hitherto remained only vaguely defined. In this work we investigated the antimicrobial mode of action of chitosan using a combination of approaches, including in vitro assays, killing kinetics, cellular leakage measurements, membrane potential estimations, and electron microscopy, in addition to transcriptional response analysis. Chitosan, whose antimicrobial activity was influenced by several factors, exhibited a dose-dependent growth-inhibitory effect. A simultaneous permeabilization of the cell membrane to small cellular components, coupled to a significant membrane depolarization, was detected. A concomitant interference with cell wall biosynthesis was not observed. Chitosan treatment of Staphylococcus simulans 22 cells did not give rise to cell wall lysis; the cell membrane also remained intact. Analysis of transcriptional response data revealed that chitosan treatment leads to multiple changes in the expression profiles of Staphylococcus aureus SG511 genes involved in the regulation of stress and autolysis, as well as genes associated with energy metabolism. Finally, a possible mechanism for chitosan's activity is postulated. Although we contend that there might not be a single classical target that would explain chitosan's antimicrobial action, we speculate that binding of chitosan to teichoic acids, coupled with a potential extraction of membrane lipids (predominantly lipoteichoic acid) results in a sequence of events, ultimately leading to bacterial death.

scholarly journals Human β-Defensin 3 Inhibits Cell Wall Biosynthesis in Staphylococci

2010 ◽  
Vol 78 (6) ◽  
pp. 2793-2800 ◽  
Author(s):  
Vera Sass ◽  
Tanja Schneider ◽  
Miriam Wilmes ◽  
Christian Körner ◽  
Alessandro Tossi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Host Defense ◽  
Transcriptional Response ◽  
Cell Wall Biosynthesis ◽  
Host Defense Peptides ◽  
Lipid Ii ◽  
Transmission Electron ◽  
Host Defense Peptide

ABSTRACT Human β-defensin 3 (hBD3) is a highly charged (+11) cationic host defense peptide, produced by epithelial cells and neutrophils. hBD3 retains antimicrobial activity against a broad range of pathogens, including multiresistant Staphylococcus aureus, even under high-salt conditions. Whereas antimicrobial host defense peptides are assumed to act by permeabilizing cell membranes, the transcriptional response pattern of hBD3-treated staphylococcal cells resembled that of vancomycin-treated cells (V. Sass, U. Pag, A. Tossi, G. Bierbaum, and H. G. Sahl, Int. J. Med. Microbiol. 298:619-633, 2008) and suggested that inhibition of cell wall biosynthesis is a major component of the killing process. hBD3-treated cells, inspected by transmission electron microscopy, showed localized protrusions of cytoplasmic contents, and analysis of the intracellular pool of nucleotide-activated cell wall precursors demonstrated accumulation of the final soluble precursor, UDP-MurNAc-pentapeptide. Accumulation is typically induced by antibiotics that inhibit membrane-bound steps of cell wall biosynthesis and also demonstrates that hBD3 does not impair the biosynthetic capacity of cells and does not cause gross leakage of small cytoplasmic compounds. In in vitro assays of individual membrane-associated cell wall biosynthesis reactions (MraY, MurG, FemX, and penicillin-binding protein 2 [PBP2]), hBD3 inhibited those enzymes which use the bactoprenol-bound cell wall building block lipid II as a substrate; quantitative analysis suggested that hBD3 may stoichiometrically bind to lipid II. We report that binding of hBD3 to defined, lipid II-rich sites of cell wall biosynthesis may lead to perturbation of the biosynthesis machinery, resulting in localized lesions in the cell wall as demonstrated by electron microscopy. The lesions may then allow for osmotic rupture of cells when defensins are tested under low-salt conditions.

scholarly journals Inhibition of Staphylococcus aureus Cell Wall Biosynthesis by Desleucyl-Oritavancin: a Quantitative Peptidoglycan Composition Analysis by Mass Spectrometry

2017 ◽  
Vol 199 (15) ◽  
Author(s):  
James D. Chang ◽  
Erin E. Foster ◽  
Aanchal N. Thadani ◽  
Alejandro J. Ramirez ◽  
Sung Joon Kim
Keyword(s):  
Mass Spectrometry ◽  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Binding Site ◽  
Mode Of Action ◽  
Composition Analysis ◽  
Edman Degradation ◽  
Glycopeptide Antibiotics ◽  
Content Type ◽  
The Cross

ABSTRACT Oritavancin is a lipoglycopeptide antibiotic that exhibits potent activities against vancomycin-resistant Gram-positive pathogens. Oritavancin differs from vancomycin by a hydrophobic side chain attached to the drug disaccharide, which forms a secondary binding site to enable oritavancin binding to the cross-linked peptidoglycan in the cell wall. The mode of action of secondary binding site was investigated by measuring the changes in the peptidoglycan composition of Staphylococcus aureus grown in the presence of desleucyl-oritavancin at subinhibitory concentration using liquid chromatography-mass spectrometry (LC-MS). Desleucyl-oritavancin is an Edman degradation product of oritavancin that exhibits potent antibacterial activities despite the damaged d-Ala–d-Ala binding site due to its functional secondary binding site. Accurate quantitative peptidoglycan composition analysis based on 83 muropeptide ions determined that cell walls of S. aureus grown in the presence of desleucyl-oritavancin showed a reduction of peptidoglycan cross-linking, increased muropeptides with a tetrapeptide-stem structure, decreased O-acetylation of MurNAc, and increased N-deacetylation of GlcNAc. The changes in peptidoglycan composition suggest that desleucyl-oritavancin targets the peptidoglycan template to induce cell wall disorder and interferes with cell wall maturation. IMPORTANCE Oritavancin is a lipoglycopeptide antibiotic with a secondary binding site that targets the cross-linked peptidoglycan bridge structure in the cell wall. Even after the loss of its primary d-Ala–d-Ala binding site through Edman degradation, desleucyl-oritavancin exhibits potent antimicrobial activities through its still-functioning secondary binding site. In this study, we characterized the mode of action for desleucyl-oritavancin's secondary binding site using LC-MS. Peptidoglycan composition analysis of desleucyl-oritavancin-treated S. aureus was performed by determining the relative abundances of 83 muropeptide ions matched from a precalculated library through integrating extracted ion chromatograms. Our work highlights the use of quantitative peptidoglycan composition analysis by LC-MS to provide insights into the mode of action of glycopeptide antibiotics.

scholarly journals SEDS-bPBP pairs direct Lateral and Septal Peptidoglycan Synthesis in Staphylococcus aureus

2019 ◽  
Author(s):  
Nathalie T. Reichmann ◽  
Andreia C. Tavares ◽  
Bruno M. Saraiva ◽  
Ambre Jousselin ◽  
Patricia Reed ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Cell Division ◽  
Late Stage ◽  
Cell Elongation ◽  
Cell Shape ◽  
Protein A ◽  
Interacting Proteins ◽  
Peptidoglycan Synthesis ◽  
Multiple Rings

Peptidoglycan (PGN) is the major component of the bacterial cell wall, a structure essential for the physical integrity and shape of the cell. Bacteria maintain cell shape by directing PGN incorporation to distinct regions of the cell, namely through the localisation of the late stage PGN synthesis proteins. These include two key protein families, SEDS transglycosylases and the bPBP transpeptidases, proposed to function in cognate pairs. Rod-shaped bacteria have two SEDS-bPBP pairs, involved in cell elongation and cell division. Here, we elucidate why coccoid bacteria, such as Staphylococcus aureus, also possess two SEDS-bPBP pairs. We determined that S. aureus RodA-PBP3 and FtsW-PBP1 likely constitute cognate pairs of interacting proteins. Lack of RodA-PBP3 decreased cell eccentricity due to deficient pre-septal PGN synthesis, whereas the depletion of FtsW-PBP1 arrested normal septal PGN incorporation. Although PBP1 is an essential protein, a mutant lacking PBP1 transpeptidase activity is viable, showing that this protein has a second function. We propose that the FtsW-PBP1 pair has a role in stabilising the divisome at midcell. In the absence of these proteins, the divisome appears as multiple rings/arcs that drive lateral PGN incorporation, leading to cell elongation. We conclude that RodA-PBP3 and FtsW-PBP1 mediate lateral and septal PGN incorporation, respectively, and that the activity of these pairs must be balanced in order to maintain coccoid morphology.

Genome-wide transcriptional profiling of the response of Staphylococcus aureus to cell-wall-active antibiotics reveals a cell-wall-stress stimulon

Microbiology ◽  
2003 ◽  
Vol 149 (10) ◽  
pp. 2719-2732 ◽  
Author(s):  
S. Utaida ◽  
P. M. Dunman ◽  
D. Macapagal ◽  
E. Murphy ◽  
S. J. Projan ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Stress Responses ◽  
Transcriptional Profiling ◽  
Wall Stress ◽  
Antibacterial Activities ◽  
Transcriptional Signature ◽  
Genome Wide ◽  
Custom Made ◽  
A Cell

The molecular events following inhibition of bacterial peptidoglycan synthesis have not been studied extensively. Previous proteomic studies have revealed that certain proteins are produced in increased amounts upon challenge of Staphylococcus aureus with cell-wall-active antibiotics. In an effort to further those studies, the genes upregulated in their expression in response to cell-wall-active antibiotics have been identified by genome-wide transcriptional profiling using custom-made Affymetrix S. aureus GeneChipsTM. A large number of genes, including ones encoding proteins involved in cell-wall metabolism (including pbpB, murZ, fmt and vraS) and stress responses (including msrA, htrA, psrA and hslO), were upregulated by oxacillin, d-cycloserine or bacitracin. This response may represent the transcriptional signature of a cell-wall stimulon induced in response to cell-wall-active agents. The findings imply that treatment with cell-wall-active antibiotics results in damage to proteins including oxidative damage. Additional genes in a variety of functional categories were upregulated uniquely by each of the three cell-wall-active antibiotics studied. These changes in gene expression can be viewed as an attempt by the organism to defend itself against the antibacterial activities of the agents.

scholarly journals Transcriptional Profiling Reveals that Daptomycin Induces the Staphylococcus aureus Cell Wall Stress Stimulon and Genes Responsive to Membrane Depolarization

2007 ◽  
Vol 52 (3) ◽  
pp. 980-990 ◽  
Author(s):  
Arunachalam Muthaiyan ◽  
Jared A. Silverman ◽  
Radheshyam K. Jayaswal ◽  
Brian J. Wilkinson
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Mode Of Action ◽  
Bacterial Infections ◽  
Antimicrobial Agents ◽  
Transcriptional Profiling ◽  
Wall Stress ◽  
Membrane Depolarization ◽  
Transcriptional Responses ◽  
Cell Wall Stress

ABSTRACT Daptomycin is a lipopeptide antibiotic that has recently been approved for treatment of gram-positive bacterial infections. The mode of action of daptomycin is not yet entirely clear. To further understand the mechanism transcriptomic analysis of changes in gene expression in daptomycin-treated Staphylococcus aureus was carried out. The expression profile indicated that cell wall stress stimulon member genes (B. J. Wilkinson, A. Muthaiyan, and R. K. Jayaswal, Curr. Med. Chem. Anti-Infect. Agents 4:259-276, 2005) were significantly induced by daptomycin and by the cell wall-active antibiotics vancomycin and oxacillin. Comparison of the daptomycin response of a two-component cell wall stress stimulon regulator VraSR mutant, S. aureus KVR, to its parent N315 showed diminished expression of the cell wall stress stimulon in the mutant. Daptomycin has been proposed to cause membrane depolarization, and the transcriptional responses to carbonyl cyanide m-chlorophenylhydrazone (CCCP) and nisin were determined. Transcriptional profiles of the responses to these antimicrobial agents showed significantly different patterns compared to those of the cell wall-active antibiotics, including little or no induction of the cell wall stress stimulon. However, there were a significant number of genes induced by both CCCP and daptomycin that were not induced by oxacillin or vancomycin, so the daptomycin transcriptome probably reflected a membrane depolarizing activity of this antimicrobial also. The results indicate that inhibition of peptidoglycan biosynthesis, either directly or indirectly, and membrane depolarization are parts of the mode of action of daptomycin.

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