INFLUENCE OF NAFCILLIN ON THE ENZYMIC LYSIS OF STAPHYLOCOCCUS AUREUS

1967 ◽  
Vol 13 (3) ◽  
pp. 321-328 ◽  
Author(s):  
George H. Warren ◽  
Jane Gray
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Proteolytic Enzymes ◽  
Cell Permeability ◽  
Cross Linking ◽  
Logarithmic Phase ◽  
Pronounced Increase ◽  
Dose Dependent ◽  
Sublethal Concentrations ◽  
Primary Action

During growth of Staphylococcus aureus cells, sublethal concentrations of nafcillin induce changes in the cell wall resulting in a pronounced increase in susceptibility to lysis by lysozyme and proteolytic enzymes. Data presented demonstrate that this property of nafcillin is dose dependent, and the relatively low concentration needed to influence lysis significantly, approximately 1/80th the minimum inhibiting concentration, suggests that we are dealing with a specific and primary action on cell wall synthesis. The enhancement in lytic response observed during the logarithmic phase of growth is consistent with the hypothesis that an impairment of cross-linking in mucopeptide synthesis occurs following exposure to nafcillin. Since heat treatment (60 °C, 20 min) of nafcillin-treated cells considerably reduces lysis, the rate and extent must depend in part on the activity of one or more autolytic factors. Enzymic lysis is also enhanced by addition of sodium bicarbonate to control and nafcillin-treated suspensions, a phenomenon interpreted as a reversible bicarbonate-induced effect on cell permeability.

scholarly journals Role of the msaABCR Operon in Cell Wall Biosynthesis, Autolysis, Integrity, and Antibiotic Resistance in Staphylococcus aureus

2019 ◽  
Vol 63 (10) ◽  
Author(s):  
Bibek G C ◽  
Gyan S. Sahukhal ◽  
Mohamed O. Elasri
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Antibiotic Resistance ◽  
Teichoic Acid ◽  
Cross Linking ◽  
Wall Defect ◽  
Content Type ◽  
Mrsa Strains ◽  
Mutant Cells

ABSTRACT Staphylococcus aureus is an important human pathogen in both community and health care settings. One of the challenges with S. aureus as a pathogen is its acquisition of antibiotic resistance. Previously, we showed that deletion of the msaABCR operon reduces cell wall thickness, resulting in decreased resistance to vancomycin in vancomycin-intermediate S. aureus (VISA). In this study, we investigated the nature of the cell wall defect in the msaABCR operon mutant in the Mu50 (VISA) and USA300 LAC methicillin-resistant Staphylococcus aureus (MRSA) strains. Results showed that msaABCR mutant cells had decreased cross-linking in both strains. This defect is typically due to increased murein hydrolase activity and/or nonspecific processing of murein hydrolases mediated by increased protease activity in mutant cells. The defect was enhanced by a decrease in teichoic acid content in the msaABCR mutant. Therefore, we propose that deletion of the msaABCR operon results in decreased peptidoglycan cross-linking, leading to increased susceptibility toward cell wall-targeting antibiotics, such as β-lactams and vancomycin. Moreover, we also observed significantly downregulated transcription of early cell wall-synthesizing genes, supporting the finding that msaABCR mutant cells have decreased peptidoglycan synthesis. More specifically, the msaABCR mutant in the USA300 LAC strain (MRSA) showed significantly reduced expression of the murA gene, whereas the msaABCR mutant in the Mu50 strain (VISA) showed significantly reduced expression of glmU, murA, and murD. Thus, we conclude that the msaABCR operon controls the balance between cell wall synthesis and cell wall hydrolysis, which is required for maintaining a robust cell wall and acquiring resistance to cell wall-targeting antibiotics, such as vancomycin and the β-lactams.

scholarly journals Role of Penicillin-Binding Protein 2 (PBP2) in the Antibiotic Susceptibility and Cell Wall Cross-Linking of Staphylococcus aureus: Evidence for the Cooperative Functioning of PBP2, PBP4, and PBP2A

2005 ◽  
Vol 187 (5) ◽  
pp. 1815-1824 ◽  
Author(s):  
Tomasz A. Łęski ◽  
Alexander Tomasz
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Antimicrobial Agents ◽  
Binding Protein ◽  
Resistant Mutant ◽  
Site Directed Mutagenesis ◽  
Cross Linking ◽  
Penicillin Binding Protein ◽  
Beta Lactam ◽  
Experimental Proof

ABSTRACT Ceftizoxime, a beta-lactam antibiotic with high selective affinity for penicillin-binding protein 2 (PBP2) of Staphylococcus aureus, was used to select a spontaneous resistant mutant of S. aureus strain 27s. The stable resistant mutant ZOX3 had an increased ceftizoxime MIC and a decreased affinity of its PBP2 for ceftizoxime and produced peptidoglycan in which the proportion of highly cross-linked muropeptides was reduced. The pbpB gene of ZOX3 carried a single C-to-T nucleotide substitution at nucleotide 1373, causing replacement of a proline with a leucine at amino acid residue 458 of the transpeptidase domain of the protein, close to the SFN conserved motif. Experimental proof that this point mutation was responsible for the drug-resistant phenotype, and also for the decreased PBP2 affinity and reduced cell wall cross-linking, was provided by allelic replacement experiments and site-directed mutagenesis. Disruption of pbpD, the structural gene of PBP4, in either the parental strain or the mutant caused a large decrease in the highly cross-linked muropeptide components of the cell wall and in the mutant caused a massive accumulation of muropeptide monomers as well. Disruption of pbpD also caused increased sensitivity to ceftizoxime in both the parental cells and the ZOX3 mutant, while introduction of the plasmid-borne mecA gene, the genetic determinant of the beta-lactam resistance protein PBP2A, had the opposite effects. The findings provide evidence for the cooperative functioning of two native S. aureus transpeptidases (PBP2 and PBP4) and an acquired transpeptidase (PBP2A) in staphylococcal cell wall biosynthesis and susceptibility to antimicrobial agents.

scholarly journals Morphological and Genetic Differences in Two Isogenic Staphylococcus aureus Strains with Decreased Susceptibilities to Vancomycin

2003 ◽  
Vol 47 (2) ◽  
pp. 568-576 ◽  
Author(s):  
Andrea Reipert ◽  
Kerstin Ehlert ◽  
Thomas Kast ◽  
Gabriele Bierbaum
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Methicillin Resistance ◽  
Resistance Mechanism ◽  
Cross Linking ◽  
Spontaneous Mutant ◽  
Chromosomal Dna ◽  
False Target ◽  
A Cell ◽  
Wall Profile

ABSTRACT Many VISA (vancomycin intermediately resistant Staphylococcus aureus) strains are characterized by increased cell wall biosynthesis and decreased cross-linking of the peptide side chains, leading to accumulation of free d-alanyl-d-alanine termini in the peptidoglycan, which act as false target sites for vancomycin. A spontaneous mutant of methicillin-resistant VISA strain SA137/93A (vancomycin MIC [E-test], 8 μg/ml), called SA137/93G, showed increased resistance to vancomycin (MIC [E-test], 12 μg/ml). Analysis of the resistance profile of the mutant revealed a loss of β-lactam resistance with a concomitant increase in resistance to glycopeptides. In both strains, cell wall thickness was 1.4-fold greater than that of control isolates. However, cross-linking of the cell wall was drastically lower in SA137/93A than in SA137/93G. The sensitivity of strain SA137/93G to β-lactams was due to loss of the β-lactamase plasmid and a deletion that comprises 32.5 kb of the methicillin resistance cassette SCCmec, as well as 65.4 kb of chromosomal DNA. A spontaneous mutant of SA137/93G with higher sensitivity to vancomycin displayed a cell wall profile similar, in some respects, to that of an fmhB mutant. Results described here and elsewhere show that the only feature common to all VISA strains is a thickened cell wall, which may play a central role in the vancomycin resistance mechanism.

scholarly journals Detection of the cell wall-affecting antibiotics at sublethal concentrations using a reporter Staphylococcus aureus harboring drp35 promoter - lacZ transcriptional fusion

BMB Reports ◽  
2010 ◽  
Vol 43 (7) ◽  
pp. 468-473 ◽  
Author(s):  
Rajkrishna Mondal ◽  
Palas K. Chanda ◽  
Amitava Bandhu ◽  
Biswanath Jana ◽  
Chia-Y. Lee ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Transcriptional Fusion ◽  
Sublethal Concentrations

scholarly journals Contribution of a Thickened Cell Wall and Its Glutamine Nonamidated Component to the Vancomycin Resistance Expressed by Staphylococcus aureus Mu50

2000 ◽  
Vol 44 (9) ◽  
pp. 2276-2285 ◽  
Author(s):  
Longzhu Cui ◽  
Hiroko Murakami ◽  
Kyoko Kuwahara-Arai ◽  
Hideaki Hanaki ◽  
Keiichi Hiramatsu
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Glutamine Synthetase ◽  
Glucose Utilization ◽  
Vancomycin Resistance ◽  
Cross Linking ◽  
Synthetase Activity ◽  
Glutamine Synthetase Activity ◽  
Peptidoglycan Synthesis ◽  
Different Levels

ABSTRACT Staphylococcus aureus Mu50, which has reduced susceptibility to vancomycin, has a remarkably thickened cell wall with an increased proportion of glutamine nonamidated muropeptides. In addition, Mu50 had enhanced glutamine synthetase andl-glutamine d-fructose-6-phosphate aminotransferase activities, which are involved in the cell-wall peptidoglycan synthesis pathway. Furthermore, significantly increased levels of incorporation of 14C-labeledd-glucose into the cell wall was observed in Mu50. Unlike afemC mutant S. aureus strain, increased levels of production of nonamidated muropeptides in Mu50 was not caused by lower levels of glutamine synthetase activity but was considered to be due to the glutamine depletion caused by increased glucose utilization by the cell to biosynthesize increased amounts of peptidoglycan. After the cells were allowed to synthesize cell wall in the absence or presence of glucose and glutamine, cells with different cell-wall thicknesses and with cell walls with different levels of cross-linking were prepared, and susceptibility testing of these cells demonstrated a strong correlation between the cell-wall thickness and the degree of vancomycin resistance. Affinity trapping of vancomycin molecules by the cell wall and clogging of the outer layers of peptidoglycan by bound vancomycin molecules were considered to be the mechanism of vancomycin resistance of Mu50. The reduced cross-linking and the increased affinity of binding to vancomycin of the Mu50 cell wall presumably caused by the increased proportion of nonamidated muropeptides may also contribute to the resistance to some extent.

scholarly journals Influence of Adhesion Force onicaAandcidAGene Expression and Production of Matrix Components in Staphylococcus aureus Biofilms

2015 ◽  
Vol 81 (10) ◽  
pp. 3369-3378 ◽  
Author(s):  
Akshay K. Harapanahalli ◽  
Yun Chen ◽  
Jiuyi Li ◽  
Henk J. Busscher ◽  
Henny C. van der Mei
Keyword(s):  
Gene Expression ◽  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Adhesion Force ◽  
Extracellular Dna ◽  
Cross Linking ◽  
Adhesion Forces ◽  
Content Type ◽  
Isogenic Mutant ◽  
Matrix Components

ABSTRACTThe majority of human infections are caused by biofilms. The biofilm mode of growth enhances the pathogenicity ofStaphylococcusspp. considerably, because once they adhere, staphylococci embed themselves in a protective, self-produced matrix of extracellular polymeric substances (EPSs). The aim of this study was to investigate the influence of forces of staphylococcal adhesion to different biomaterials onicaA(which regulates the production of EPS matrix components) andcidA(which is associated with cell lysis and extracellular DNA [eDNA] release) gene expression inStaphylococcus aureusbiofilms. Experiments were performed withS. aureusATCC 12600 and its isogenic mutant,S. aureusATCC 12600 Δpbp4, deficient in peptidoglycan cross-linking. Deletion ofpbp4was associated with greater cell wall deformability, while it did not affect the planktonic growth rate, biofilm formation, cell surface hydrophobicity, or zeta potential of the strains. The adhesion forces ofS. aureusATCC 12600 were the strongest on polyethylene (4.9 ± 0.5 nN), intermediate on polymethylmethacrylate (3.1 ± 0.7 nN), and the weakest on stainless steel (1.3 ± 0.2 nN). The production of poly-N-acetylglucosamine, eDNA presence, and expression oficaAgenes decreased with increasing adhesion forces. However, no relation between adhesion forces andcidAexpression was observed. The adhesion forces of the isogenic mutantS. aureusATCC 12600 Δpbp4(deficient in peptidoglycan cross-linking) were much weaker than those of the parent strain and did not show any correlation with the production of poly-N-acetylglucosamine, eDNA presence, or expression of theicaAandcidAgenes. This suggests that adhesion forces modulate the production of the matrix molecule poly-N-acetylglucosamine, eDNA presence, andicaAgene expression by inducing nanoscale cell wall deformation, with cross-linked peptidoglycan layers playing a pivotal role in this adhesion force sensing.

Influence of Calcium Ions on the Plant Cell Surface: Membrane Fusions and Conformational Changes

1974 ◽  
Vol 32 ◽  
pp. 154-155
Author(s):  
D. James Morré ◽  
Charles E. Bracker ◽  
William J. VanDerWoude
Keyword(s):  
Cell Wall ◽  
Cell Surface ◽  
Conformational Changes ◽  
Calcium Ions ◽  
Surface Membrane ◽  
Carboxyl Groups ◽  
Cross Linking ◽  
Ultrastructural Evidence ◽  
Glycine Max L ◽  
Wall Extensibility

Calcium ions in the concentration range 5-100 mM inhibit auxin-induced cell elongation and wall extensibility of plant stems. Inhibition of wall extensibility requires that the tissue be living; growth inhibition cannot be explained on the basis of cross-linking of carboxyl groups of cell wall uronides by calcium ions. In this study, ultrastructural evidence was sought for an interaction of calcium ions with some component other than the wall at the cell surface of soybean (Glycine max (L.) Merr.) hypocotyls.

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