Metal binding by the peptidoglycan sacculus of <i>Escherichia coli</i> K-12

Hoyle, B.; Beveridge, Terry J.

doi:10.1139/m84-031

Cited by 96 publications

(47 citation statements)

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“…Bacillus on the other hand showed a better tolerance and uptake with Cd (Graph 5). Similar findings were reported with respect to Cd biosorption studies [3,4]. It was also reported that metal binding capacities of E. coli was relatively higher than Bacillus by [5].…”

Section: Discussionsupporting

confidence: 88%

Effect of Heavy Metal Uptake by E. coli and Bacillus sps

Vijayadeep¹,

Ps²

2014

J Bioremed Biodeg

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Over the past century, unrestricted mining, extensive industrialization, modern agricultural practices and faulty waste disposal methods have resulted in the release of unprecedented levels of toxic heavy metals like Cd, Hg, Ag, Sn, Pb, Cu, Co, Mn, Zn, etc into the environment. Many metals are essential for microbial growth in less concentration, yet are toxic in higher concentrations. Biosorption is an attractive alternative approach which involves the binding or adsorption of heavy metals to living or dead cells. Many microbes have the ability to selectively accumulate metals.The present study is intended to analyze the uptake systems of Bacillus and E. coli against different conc. of heavy metals like Zn, Cu, Cd, and Hg in their salt form incorporated into nutrient broth medium observed over a regular interval of time. Analysis was based on how much of the metal from the original conc. Used was left behind in the media after the rest being up taken by the organism. This was done using AAS which was indirectly the representation of percent uptake of heavy metal by the respective organism.The study showed that Gram -ve organisms like E. coli exhibited more resistance to metals like Zn, Cu and Hg in relative comparison with Gram +ve organisms like Bacillus. Bacillus sps was less sensitive to effect of Cd than in E. coli.

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Section: Discussionsupporting

confidence: 88%

Effect of Heavy Metal Uptake by E. coli and Bacillus sps

Vijayadeep¹,

Ps²

2014

J Bioremed Biodeg

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“…Whole-cell pellets were then resuspended in 100 ml 25 mM sodium phosphate buffer (pH 6.0). Insoluble peptidoglycan and associated teichoic acids were extracted using the boiling 4% sodium dodecyl sulfate (SDS) procedure described by Holye and Beveridge (22), taking care to preserve natural levels of O acetylation (9). The SDS-insoluble cell wall material (for convenience referred to below as peptidoglycan) was recovered by ultracentrifugation at 160,000 ϫ g for 55 min at 25°C, washed at least four times with 25 mM sodium phosphate buffer (pH 6.0), and lyophilized.…”

Section: Methodsmentioning

confidence: 99%

Peptidoglycan O Acetylation and Autolysin Profile ofEnterococcus faecalisin the Viable but Nonculturable State

et al. 2006

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The O acetylation of peptidoglycan occurs specifically at the C-6 hydroxyl group of muramoyl residues. Using a combination of high-performance liquid chromatography-based organic acid analysis and carbohydrate analysis by high-pH anion-exchange chromatography, we determined that strains of Entercoccus durans, E. faecalis, E. faecium, and E. hirae produce O-acetylated peptidoglycan. The levels of O acetylation ranged from 19% to 72% relative to the muramic acid content, and they were found to vary with the growth phase of the culture. Increases of 10 to 40% in O acetylation were observed with cultures entering the stationary phase. Cells of E. faecalis in the viable but nonculturable (VBNC) state had the highest levels of peptidoglycan O acetylation. The presence of this modification to peptidoglycan was shown to inhibit the action of hen egg white lysozyme in a concentration-dependent manner. Zymography using sodium dodecyl sulfate-polyacrylamide gel electrophoresis gels containing either O-acetylated or chemically de-O-acetylated peptidoglycan was used to monitor the production of specific autolysins in E. faecalis. Differences in the expression of specific autolysins were observed with the age of the culture, and VBNC E. faecalis produced the highest levels of these enzymes. This technique also permitted classification of the enterococcal autolysins into enzymes that preferentially hydrolyze either O-acetylated or non-O-acetylated peptidoglycan and enzymes that show no apparent preference for either substrate type.The gram-positive, gut commensal bacterium Enterococcus faecalis is the causative agent of 90% of all enterococcal infections, which include endocarditis, bacteremia, and urinary tract infections. Of these, urinary tract infections are the most common, and the majority of them are acquired nosocomially. E. faecalis infections pose problems for the clinician because of their resistance to multiple antibiotics, sometimes including vancomycin, the drug of last resort for many gram-positive infections (recently reviewed in references 14, 19, and 32). To exacerbate this situation, this bacterium has been shown to persist in a mouse model for extended periods of time in the kidney (26). This persistence is thought to result from the cell's ability to enter the viable but nonculturable (VBNC) state, a feature first described for E. faecalis by Lleo et al. (30). VBNC E. faecalis, like other VBNC pathogenic bacteria, appears to retain its pathogenicity genes and is able to resume active growth upon restoration of the optimal environmental conditions (reference 30 and references therein). While in this state, E. faecalis cells have an irregular morphology, and there are concomitant alterations in the molecular architecture of the peptidoglycan sacculus (39). However, the changes observed in the peptidoglycan composition do not readily account for the persistence associated with the VBNC enterococci. One possible explanation for the apparent resilience of VBNC E. faecalis could involve a modification to the pep...

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“…Two liters of P. aeruginosa PAO1 in TSB was incubated at 37ЊC and 125 rpm to obtain an optical density at 600 nm (OD 600 ) of 1.0. After centrifugation at 5,000 ϫ g for 30 min, the cell pellet was resuspended in distilled water, and murein sacculi were prepared by boiling cells in 4% (final concentration) SDS for 3 h as described previously (13). Murein sacculi were sonicated to homogeneity prior to incorporation into the polyacrylamide gel used in the zymogram system.…”

Section: Bacteriamentioning

confidence: 99%

A major autolysin of Pseudomonas aeruginosa: subcellular distribution, potential role in cell growth and division and secretion in surface membrane vesicles

1996

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A 26-kDa murein hydrolase is the major autolysin of Pseudomonas aeruginosa PAO1, and its expression can be correlated with the growth and division of cells in both batch and synchronously growing cultures. In batch cultures, it is detected primarily during the mid-exponential growth phase, and in synchronous cultures, it is detected primarily during the cell elongation and division phases. Immunogold labeling of thin sections of P. aeruginosa using antibodies raised against the 26-kDa autolysin revealed that it is associated mainly with the cell envelope and in particular within the periplasm. It is also tightly bound to the peptidoglycan layer, since murein sacculi, isolated by boiling 4% sodium dodecyl sulfate treatment, could also be immunogold labeled. Since division is due to cell constriction in this P. aeruginosa strain (septa are rarely seen), we cannot comment on the autolysin's contribution to septation, although constriction sites were always heavily labeled. Some labeling was also found in the cytoplasm, and this was thought to be due to the de novo synthesis of the enzyme before translocation to the periplasm. Interestingly, the autolysin was also found to be associated with natural membrane vesicles which blebbed from the surface during cell growth; the enzyme is therefore part of the complex makeup of these membrane packages of secreted materials (J. L. Kadurugamuwa and T. J. Beveridge, J. Bacteriol. 177:3998-4008, 1995). The expression of these membrane vesicles was correlated with the expression of B-band lipopolysaccharide.

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Metal binding by the peptidoglycan sacculus of Escherichia coli K-12

Cited by 96 publications

References 0 publications

Effect of Heavy Metal Uptake by E. coli and Bacillus sps

Effect of Heavy Metal Uptake by E. coli and Bacillus sps

Peptidoglycan O Acetylation and Autolysin Profile ofEnterococcus faecalisin the Viable but Nonculturable State

A major autolysin of Pseudomonas aeruginosa: subcellular distribution, potential role in cell growth and division and secretion in surface membrane vesicles

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