scholarly journals Non-protein components of the cell surface of Staphylococcus aureus

1968 ◽  
Vol 107 (6) ◽  
pp. 817-821 ◽  
Author(s):  
A. M. James ◽  
J. E. Brewer
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Surface ◽  
Teichoic Acid ◽  
Surface Damage ◽  
Sodium Metaperiodate ◽  
Maximum Value ◽  
Dependent Change ◽  
Ph Dependent ◽  
Pass Through ◽  
Protein Components

1. pH–mobility curves of various laboratory strains of Staphylococcus aureus are non-sigmoid in shape, and all pass through a maximum value in the range pH4–5. 2. The maxima in the curves are not due to incomplete washing of the cells, adsorption of buffer components or irreversible surface damage. 3. Mild oxidation of the cell-surface teichoic acid with sodium metaperiodate gives cells that have typical sigmoid pH–mobility curves, characteristic of either a simple carboxyl surface or a mixed carboxyl–amino surface. 4. The results are discussed in terms of a pH-dependent change in the configuration of the teichoic acid molecules at the surface.

scholarly journals The Staphylococcus aureus Methicillin Resistance Factor FmtA Is a d-Amino Esterase That Acts on Teichoic Acids

mBio ◽  
2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Muhammad M. Rahman ◽  
Howard N. Hunter ◽  
Shamina Prova ◽  
Vidhu Verma ◽  
Aneela Qamar ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Cell Division ◽  
Cell Surface ◽  
Biofilm Formation ◽  
Negative Charge ◽  
Methicillin Resistance ◽  
Teichoic Acid ◽  
Teichoic Acids ◽  
Phosphate Backbone

ABSTRACT The methicillin resistance factor encoded by fmtA is a core member of the Staphylococcus aureus cell wall stimulon, but its function has remained elusive for the past two decades. First identified as a factor that affects methicillin resistance in S. aureus strains, FmtA was later shown to interact with teichoic acids and to localize to the cell division septum. We have made a breakthrough in understanding FmtA function. We show that FmtA hydrolyzes the ester bond between d -Ala and the backbone of teichoic acids, which are polyglycerol-phosphate or polyribitol-phosphate polymers found in the S. aureus cell envelope. FmtA contains two conserved motifs found in serine active-site penicillin-binding proteins (PBPs) and β-lactamases. The conserved SXXK motif was found to be important for the d -amino esterase activity of FmtA. Moreover, we show that deletion of fmtA (Δ fmtA ) led to higher levels of d -Ala in teichoic acids, and this effect was reversed by complementation of Δ fmtA with fmtA . The positive charge on d -Ala partially masks the negative charge of the polyol-phosphate backbone of teichoic acids; hence, a change in the d -Ala content will result in modulation of their charge. Cell division, biofilm formation, autolysis, and colonization are among the many processes in S. aureus affected by the d -Ala content and overall charge of the cell surface teichoic acids. The esterase activity of FmtA and the regulation of fmtA suggest that FmtA functions as a modulator of teichoic acid charge, thus FmtA may be involved in S. aureus cell division, biofilm formation, autolysis, and colonization. IMPORTANCE Teichoic acids are involved in cell division, cell wall synthesis, biofilm formation, attachment of bacteria to artificial surfaces, and colonization. However, the function of teichoic acids is not fully understood. Modification by glycosylation and/or d -alanylation of the polyol-phosphate backbone of teichoic acids is important in the above cell processes. The intrinsic negative charge of teichoic acid backbone plays a role in the charge and/or pH of the bacterial surface, and d -alanylation represents a means through which bacteria modulate the charge or the pH of their surfaces. We discovered that FmtA removes d -Ala from teichoic acids. We propose FmtA may provide a temporal and spatial regulation of the bacterial cell surface charge in two ways, by removing the d -Ala from LTA to make it available to wall teichoic acid (WTA) in response to certain conditions and by removing it from WTA to allow the cell to reset its surface charge to a previous condition.

scholarly journals GpsB coordinates cell division and cell surface decoration by wall teichoic acids in Staphylococcus aureus

2021 ◽  
Author(s):  
Lauren R. Hammond ◽  
Sebastian J. Khan ◽  
Michael D. Sacco ◽  
Catherine Spanoudis ◽  
Abigail Hough ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Division ◽  
Cell Surface ◽  
Teichoic Acid ◽  
Model Organisms ◽  
Bacterial Cell Division ◽  
Human Pathogens ◽  
Wall Teichoic Acid ◽  
Surface Decoration ◽  
Multiple Species

Bacterial cell division is a complex and highly regulated process requiring the coordination of many different proteins. Despite substantial work in model organisms, our understanding of the systems regulating cell division in non-canonical organisms, including critical human pathogens, is far from complete. One such organism is Staphylococcus aureus, a spherical bacterium that lacks known cell division regulatory proteins. Recent studies on GpsB, a protein conserved within the Firmicutes phylum, have provided insight into cell division regulation in S. aureus and other related organisms. It has been revealed that GpsB coordinates cell division and cell wall synthesis in multiple species by interacting with Penicillin Binding Proteins (PBPs) and other partners. In S. aureus, we have previously shown that GpsB directly regulates FtsZ polymerization. In this study, using Bacillus subtilis as a tool, we isolated intragenic and extragenic spontaneous suppressor mutants that abrogate the lethality of S. aureus GpsB overproduction in B. subtilis. Through characterization of these mutants, we identified several key residues important for the function of GpsB. Furthermore, we discovered an additional role for GpsB in wall teichoic acid (WTA) biosynthesis in S. aureus. Specifically, we show that GpsB directly interacts with the wall teichoic acid export protein TarG using a bacterial two-hybrid analysis. We also identified a three-residue motif in GpsB that is crucial for this interaction. Based on the analysis of the localization of TagG in B. subtilis and its homolog TarG in S. aureus, it appears that WTA machinery is a part of the divisome complex. As such, we show additional evidence to the growing body of work that suggests that along with peptidoglycan synthesis, WTA biosynthesis and export may take place at the site of cell division. Taken together, this research illustrates how GpsB performs an essential function in S. aureus by directly linking the tightly regulated cell cycle processes of cell division and WTA-mediated cell surface decoration.

Gold labeling of teichoic acid on adjacent surfaces of staphylococcus aureus

1990 ◽  
Vol 48 (3) ◽  
pp. 578-579
Author(s):  
Margaret Hukee
Keyword(s):  
Staphylococcus Aureus ◽  
Teichoic Acid ◽  
Protein Labeling ◽  
Minimal Amount ◽  
Section Thickness ◽  
Double Labeling ◽  
Parallel Surfaces ◽  
Supporting Membrane

Gold labeling of two antigens (double labeling) is often done on two section surfaces separated by section thickness. Whether labeling is done on both sides of the same section or on two parallel surfaces separated by section thickness (PSSST), comparable results are dependent on an equal number of epitopes being exposed at each surface. We propose a method to study protein labeling within the same field of proteins, by examining two directly adjacent surfaces that were split during sectioning. The number of labeling sites on adjacent surfaces (AS) were compared to sites on PSSST surfaces in individual bacteria.Since each bacteria needed to be recognizable in all three section surfaces, one-hole grids were used for labeling. One-hole grids require a supporting membrane and excessive handling during labeling often ruptures the membrane. To minimize handling, a labeling chamber was designed that is inexpensive, disposable, minimizes contamination, and uses a minimal amount of solution.

Reactive Ion Etching Induced Surface Damage of Silicon Carbide

2005 ◽  
Vol 483-485 ◽  
pp. 765-768 ◽  
Author(s):  
Jun Hai Xia ◽  
E. Rusli ◽  
R. Gopalakrishnan ◽  
S.F. Choy ◽  
Chin Che Tin ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Reactive Ion Etching ◽  
Surface Damage ◽  
Textured Surface ◽  
Rf Power ◽  
Power Devices ◽  
Ion Etching ◽  
Maximum Value ◽  
Wide Range ◽  
Coarse Surface

Reactive ion etching of SiC induced surface damage, e.g., micromasking effect induced coarse and textured surface, is one of the main concerns in the fabrication of SiC based power devices [1]. Based on CHF3 + O2 plasma, 4H-SiC was etched under a wide range of RF power. Extreme coarse and textured etched surfaces were observed under certain etching conditions. A super-linear relationship was found between the surface roughness and RF power when the latter was varied from 40 to 160 W. A further increase in the RF power to 200 W caused the surface roughness to drop abruptly from its maximum value of 182.4 nm to its minimum value of 1.3 nm. Auger electron spectroscopy (AES) results revealed that besides the Al micromasking effect, the carbon residue that formed a carbon-rich layer, could also play a significant role in affecting the surface roughness. Based on the AES results, an alternative explanation on the origin of the coarse surface is proposed.

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