scholarly journals Comparison of Antibacterial Mode of Action of Silver Ions and Silver Nanoformulations With Different Physico-Chemical Properties: Experimental and Computational Studies

2021 ◽  
Vol 12 ◽  
Author(s):  
Anna Kędziora ◽  
Robert Wieczorek ◽  
Mateusz Speruda ◽  
Iva Matolínová ◽  
Tomasz M. Goszczyński ◽  
...  
Keyword(s):  
Computational Methods ◽  
Mode Of Action ◽  
Chemical Properties ◽  
Silver Ions ◽  
Metallic Silver ◽  
Side Chains ◽  
Bacterial Cells ◽  
E Coli ◽  
Channel One ◽  
Rich Side

The aim of this study was to compare the antibacterial mode of action of silver ions (Ag+) and selected silver nanoformulations against E. coli strains (E. coli J53, Escherichia coli BW25113 and its derivatives: Δ ompA, Δ ompC, Δ ompF, Δ ompR, ompRG596AcusSG1130A, cusSG1130A). In this research we used various experimental methods and techniques such as determination of the minimal inhibitory concentration, flow cytometry, scanning electron microscopy, circular dichroism as well as computational methods of theoretical chemistry. Thanks to the processing of bacteria and silver samples (ions and nanoformulations), we were able to determine the bacterial sensitivity to silver samples, detect reactive oxygen species (ROS) in the bacterial cells, visualize the interaction of silver samples with the bacterial cells, and identify their interactions with proteins. Differences between the mode of action of silver ions and nanoformulations and the action of nanoformulations themselves were revealed. Based on the results of computational methods, we proposed an explanation of the differences in silver-outer protein interaction between silver ions and metallic silver; in general, the Ag0 complexes exhibit weaker interaction than Ag+ ones. Moreover, we identified two gutter-like areas of the inner layer of the ion channel: one more effective, with oxygen-rich side chains; and another one less effective, with nitrogen-rich side chains.

scholarly journals Effect of Chloride Ions on the Point-of-Use Drinking Water Disinfection Performance of Porous Ceramic Media Embedded with Metallic Silver and Copper

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1625
Author(s):  
Rekha Singh ◽  
Woohang Kim ◽  
James A. Smith
Keyword(s):  
Drinking Water ◽  
Porous Ceramic ◽  
Chloride Ion ◽  
Silver Ions ◽  
Chloride Ions ◽  
Ion Concentration ◽  
Metallic Silver ◽  
E Coli ◽  
Ion Concentrations ◽  
Copper Release

This study quantifies the effects of chloride ions on silver and copper release from porous ceramic cubes embedded with silver and copper and its effect on E. coli disinfection in drinking water. Log-reduction of E. coli by silver ions decreased after 4 h of contact time as the chloride ion concentration increased from 0 to 250 mg/L but, it was not changed by copper ions under the same conditions. For silver addition by silver-ceramic cubes, log reductions of E. coli decreased sharply from 7.2 to 1.6 after 12 h as the chloride concentration increased from 0 to 250 mg/L. For the silver-ceramic cube experiments, chloride ion also reduced the total silver concentration in solution. After 24 h, total silver concentrations in solution decreased from 61 µg/L to 20 µg/L for corresponding chloride ion concentrations. According to the MINTEQ equilibrium model analysis, the decrease in disinfection ability with silver embedded ceramic cubes could be the result of precipitation of silver ions as silver chloride. This suggests that AgCl was precipitating within the pore space of the ceramic. These results indicate that, although ionic silver is a highly effective disinfectant for E. coli, the presence of chloride ions can significantly reduce disinfection efficacy. For copper-ceramic cubes, log reductions of E. coli by copper embedded cubes increased from 1.2 to 1.5 when chloride ion concentration increased from 0 to 250 mg/L. Total copper concentrations in solution increased from 4 µg/L to 14 µg/L for corresponding chloride ion concentrations. These results point towards the synergistic effect of chloride ions on copper oxidation as an increased concentration of chloride enhances copper release.

scholarly journals Antibacterial Properties of a Novel Zirconium Phosphate-Glycinediphosphonate Loaded with Either Zinc or Silver

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3184 ◽  
Author(s):  
Davide Campoccia ◽  
Stefano Ravaioli ◽  
Riccardo Vivani ◽  
Anna Donnadio ◽  
Eleonora Vischini ◽  
...  
Keyword(s):  
Zirconium Phosphate ◽  
Antibacterial Properties ◽  
Colloidal Suspensions ◽  
Silver Ions ◽  
Colloidal Dispersions ◽  
Metallic Silver ◽  
Minimal Bactericidal Concentration ◽  
Orthopaedic Implant ◽  
E Coli ◽  
Material Forming

A novel compound consisting of a zirconium phosphate-glycinediphosphonate (ZPGly) has recently been introduced. This 2D-structured material forming nanosheets was exfoliated under appropriate conditions, producing colloidal aqueous dispersions (ZPGly-e) which were then loaded with zinc (Zn/ZPGly) or silver ions. Silver ions were subsequently reduced to produce metallic silver nanoparticles on exfoliated ZPGly nanosheets (Ag@ZPGly). In the search for new anti-infective materials, the present study investigated the properties of colloidal dispersions of ZPGly-e, Zn/ZPGly, and Ag@ZPGly. Ag@ZPGly was found to be a bactericidal material and was assayed to define its minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) on the five most prevalent pathogens of orthopaedic implant infections, namely: Staphylococcus aureus ATCC25923, Staphylococcus epidermidis RP62A, Enterococcus faecalis ATCC29212, Escherichia coli ATCC51739, and Pseudomonas aeruginosa ATCC27853. MIC and MBC were in the range of 125–250 μg/mL and 125–1000 μg/mL, respectively, with E. coli being the most sensitive species. Even colloidal suspensions of exfoliated ZPGly nanosheets and Zn/ZPGly exhibited some intrinsic antibacterial properties, but only at greater concentrations. Unexpectedly, Zn/ZPGly was less active than ZPGly-e.

Antimicrobial Activity of Silver Nanoparticles Synthesized by Streptomyces Species JF714876

2012 ◽  
Vol 5 (1) ◽  
pp. 1638-1642 ◽  
Author(s):  
Vidyasagar G M ◽  
Shankaravva B ◽  
R Begum ◽  
Imrose ◽  
Sagar R ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Silver Nanoparticles ◽  
Silver Ions ◽  
Human Beings ◽  
Streptomyces Species ◽  
Force Microscopy ◽  
E Coli ◽  
Extracellular Synthesis ◽  
Atomic Force ◽  
Uv Visible

Microorganisms like fungi, actinomycetes and bacteria are considered nanofactories and are helpful in the production of nanoparticles useful in the welfare of human beings. In the present study, we investigated the production of silver nanoparticles from Streptomyces species JF714876. Extracellular synthesis of silver nanoparticles by Streptomyces species was carried out using two different media. Silver nanoparticles were examined using UV-visible, IR and atomic force microscopy. The size of silver nanoparticles was in the range of 80-100 nm. Antimicrobial activity of silver nanoparticle against bacteria such as E. coli, S. aureus, and dermatophytes like T. rubrum and T. tonsurans was determined. Thus, this study suggests that the Streptomyces sp. JF741876 can produce silver ions that can be used as an antimicrobial substance.

Toxic Effect of 2-ethyl (bicyclo[2.2.1] heptane) on Bacterial Cells

2019 ◽  
Vol 35 (6) ◽  
pp. 67-72 ◽  
Author(s):  
I.V. Manukhov ◽  
L.S. Yaguzhinsky ◽  
M.V. Bermeshev ◽  
M.A. Zisman ◽  
V.G. Pevgov ◽  
...  
Keyword(s):  
Toxic Effect ◽  
Atmospheric Oxygen ◽  
Inducible Promoter ◽  
Oxygen Species ◽  
Bacterial Cells ◽  
Unique Identifier ◽  
E Coli ◽  
Lux Biosensors ◽  
High Level ◽  
Ministry Of Higher Education

Toxic effect of 2-ethylnorbornane (2-ethyl(bicyclo[2.2.1]heptane) (EBH)) on bacteria has been studied using the E. coli pRecA-lux and E. coli pKatG- lux cells as lux-biosensors. It was shown that the addition of EBH to the incubation medium leads to death and growth retardation, high level oxidative stress and DNA damage in E. coli cells. It is assumed that the oxidation of EBH with atmospheric oxygen causes the formation of reactive oxygen species in the medium, which makes a major contribution to the toxicity of this substance. biosensor, luciferase, bioluminescence, inducible promoter, PrecA, PkatG The authors are grateful to Stanislav Filippovich Chalkin for the development of interdisciplinary ties in the scientific community. The work was financially supported by the Ministry of Higher Education and Science of Russia (Project Unique Identifier RFMEFI60417X0181, Agreement No. 14.604.21.0181 of 26.09.2017).

Decomposition of hydrogen peroxide on nickel-silver two-component catalyst

1984 ◽  
Vol 49 (10) ◽  
pp. 2222-2230 ◽  
Author(s):  
Viliam Múčka ◽  
Rostislav Silber
Keyword(s):  
Hydrogen Peroxide ◽  
Chemical Properties ◽  
Silver Ions ◽  
Surface Concentration ◽  
Chloride Ions ◽  
Nickel Silver ◽  
Silver Catalysts ◽  
Physico Chemical ◽  
Low Degree ◽  
Defective Crystal

The catalytic and physico-chemical properties of low-temperature nickel-silver catalysts with nickel oxide concentrations up to 43.8% (m/m) are examined via decomposition of hydrogen peroxide in aqueous solution. The mixed catalysts prepared at 250°C are composed of partly decomposed silver carbonate or oxide and nickel carbonate or hydroxide decomposed to a low degree only and exhibiting a very defective crystal structure. The activity of these catalysts is determined by the surface concentration of silver ions, which is affected by the nickel component present. The latter also contributes to the thermal stability of the catalytic centres of the silver component, viz. the Ag+ ions. The concentration of these ions varies with the temperature of the catalyst treatment, the activity varies qualitatively in the same manner, and the system approaches the Ag-NiO composition. The catalytic centres are very susceptible to poisoning by chloride ions. A previous exposition of the catalyst to a gamma dose of 10 kGy from a 60Co source has no measurable effect on the physico-chemical properties of the system.

scholarly journals Binding Site of the Bridged Macrolides in the Escherichia coli Ribosome

2005 ◽  
Vol 49 (1) ◽  
pp. 281-288 ◽  
Author(s):  
Liqun Xiong ◽  
Yakov Korkhin ◽  
Alexander S. Mankin
Keyword(s):  
Escherichia Coli ◽  
Tight Binding ◽  
Dimethyl Sulfate ◽  
23S Rrna ◽  
Side Chain ◽  
Macrolide Antibiotics ◽  
Side Chains ◽  
Alkyl Aryl ◽  
E Coli ◽  
Exit Tunnel

ABSTRACT Ketolides represent the latest group of macrolide antibiotics. Tight binding of ketolides to the ribosome appears to correlate with the presence of an extended alkyl-aryl side chain. Recently developed 6,11-bridged bicyclic ketolides extend the spectrum of platforms used to generate new potent macrolides with extended alkyl-aryl side chains. The purpose of the present study was to characterize the site of binding and the action of bridged macrolides in the ribosomes of Escherichia coli. All the bridged macrolides investigated efficiently protected A2058 and A2059 in domain V of 23S rRNA from modification by dimethyl sulfate and U2609 from modification by carbodiimide. In addition, bridged macrolides that carry extended alkyl-aryl side chains protruding from the 6,11 bridge protected A752 in helix 35 of domain II of 23S rRNA from modification by dimethyl sulfate. Bridged macrolides efficiently displaced erythromycin from the ribosome in a competition binding assay. The A2058G mutation in 23S rRNA conferred resistance to the bridged macrolides. The U2609C mutation, which renders E. coli resistant to the previously studied ketolides telithromycin and cethromycin, barely affected cell susceptibility to the bridged macrolides used in this study. The results of the biochemical and genetic studies indicate that in the E. coli ribosome, bridged macrolides bind in the nascent peptide exit tunnel at the site previously described for other macrolide antibiotics. The presence of the side chain promotes the formation of specific interactions with the helix 35 of 23S rRNA.

Solubilities of the silver halides in propylene carbonate mixtures with bis(trifluoroethyl)sulfite

1977 ◽  
Vol 55 (13) ◽  
pp. 2499-2503 ◽  
Author(s):  
Mark Salomon
Keyword(s):  
Propylene Carbonate ◽  
Inductive Effect ◽  
Mixed Solvents ◽  
Chemical Properties ◽  
Silver Ions ◽  
Halide Ions ◽  
Silver Halides

The complex solubilities of AgCl, AgBr, and AgI have been measured in several mixed solvents containing propylene carbonate and bis(trifluoroethyl)sulfite. The results indicate that a large inductive effect destabilizes the solvation of silver ions whereas the halide ions appear to be stabilized by coordination with the sulfinyl sulfur. Several physio-chemical properties of pure bis(trifluoroethyl)sulfite are reported.

One-Step Preparation of Competent E. coli: Transformation and Storage of Bacterial Cells in the Same Solution

2021 ◽  
Vol 2021 (11) ◽  
pp. pdb.prot101212 ◽  
Author(s):  
Michael R. Green ◽  
Joseph Sambrook
Keyword(s):  
Escherichia Coli ◽  
Convenient Method ◽  
Plasmid Dna ◽  
Transformation Efficiency ◽  
Bacterial Cells ◽  
E Coli ◽  
One Step ◽  
And Storage

This protocol describes a convenient method for the preparation, use, and storage of competent Escherichia coli. The reported transformation efficiency of this method is ∼5 × 107 transformants/µg of plasmid DNA.

PBP4 and PBP5 are involved in regulating exopolysaccharide synthesis during Escherichia coli biofilm formation

Microbiology ◽  
2021 ◽  
Vol 167 (3) ◽  
Author(s):  
Sathi Mallick ◽  
Shanti Kiran ◽  
Tapas Kumar Maiti ◽  
Anindya S. Ghosh
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
Type Species ◽  
Pentose Phosphate ◽  
Bacterial Cells ◽  
Surface Adhesion ◽  
Content Type ◽  
Penicillin Binding Proteins ◽  
E Coli ◽  
Link Type

Escherichia coli low-molecular-mass (LMM) Penicillin-binding proteins (PBPs) help in hydrolysing the peptidoglycan fragments from their cell wall and recycling them back into the growing peptidoglycan matrix, in addition to their reported involvement in biofilm formation. Biofilms are external slime layers of extra-polymeric substances that sessile bacterial cells secrete to form a habitable niche for themselves. Here, we hypothesize the involvement of Escherichia coli LMM PBPs in regulating the nature of exopolysaccharides (EPS) prevailing in its extra-polymeric substances during biofilm formation. Therefore, this study includes the assessment of physiological characteristics of E. coli CS109 LMM PBP deletion mutants to address biofilm formation abilities, viability and surface adhesion. Finally, EPS from parent CS109 and its ΔPBP4 and ΔPBP5 mutants were purified and analysed for sugars present. Deletions of LMM PBP reduced biofilm formation, bacterial adhesion and their viability in biofilms. Deletions also diminished EPS production by ΔPBP4 and ΔPBP5 mutants, purification of which suggested an increased overall negative charge compared with their parent. Also, EPS analyses from both mutants revealed the appearance of an unusual sugar, xylose, that was absent in CS109. Accordingly, the reason for reduced biofilm formation in LMM PBP mutants may be speculated as the subsequent production of xylitol and a hindrance in the standard flow of the pentose phosphate pathway.

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