scholarly journals EXTRACELLULAR BIOSYNTHESIS, OPTIMIZATION, CHARACTERIZATION AND ANTIMICROBIAL POTENTIAL OF ESCHERICHIA COLI D8 SILVER NANOPARTICLES

2021 ◽  
Vol 10 (4) ◽  
pp. 648-656
Keyword(s):  
Escherichia Coli ◽  
Silver Nanoparticles ◽  
Antimicrobial Potential ◽  
Extracellular Biosynthesis

scholarly journals Extracellular Biosynthesis of Silver Nanoparticles Using Escherichia coli ATCC 8739, Bacillus subtilis ATCC 6633, and Streptococcus thermophilus ESh1 and Their Antimicrobial Activities

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Abd El-Raheem R. El-Shanshoury ◽  
Sobhy E. ElSilk ◽  
Mohamed E. Ebeid
Keyword(s):  
Escherichia Coli ◽  
Silver Nanoparticles ◽  
Bacillus Subtilis ◽  
Aqueous Media ◽  
Streptococcus Thermophilus ◽  
Antimicrobial Activities ◽  
Silver Ion ◽  
Metallic Silver ◽  
Extracellular Biosynthesis

The development of reliable and eco-friendly organisms of silver nanomaterials is an important aspect of current nanotechnology research and application. Recently, microorganisms have been explored as potential biofactory for synthesis of silver nanoparticles. In this study, through screening of common bacteria, we report extracellular biosynthesis of metallic silver nanoparticles by the reduction of aqueous Ag+ using Escherichia coli ATCC 8739, Bacillus subtilis ATCC 6633, and Streptococcus thermophilus ESh1 as potential candidates for the rapid synthesis of silver nanoparticles. The culture supernatant of silver nanoparticles biosynthesis by reduction of silver ion coming in contact with the cell filtrate was fast and was formed within few minutes. UV-visible spectrum of the aqueous media obtained from the above bacteria containing silver ion showed a peak around 420 nm corresponding to the plasmon absorbance of silver nanoparticles. Transmission electron microscopy (TEM) micrographs showed formation of well-dispersed silver nanoparticles in the range of 5–25 nm. X-ray diffraction (XRD) of silver nanoparticles exhibited 2θ values corresponding to the silver nanocrystal. In vitro studies indicated that the formed silver nanoparticles showed variable antimicrobial activity against Escherichia coli, Bacillus subtilis, Salmonella typhimurium, Klebsiella pneumoniae, Staphylococcus aureus, and Pseudomonas aeruginosa and the fungus like yeast (Candida albicans). The diameter of inhibition zone varied according to the silver nanocrystal concentration and the test microorganism.

Analysis of antimicrobial silver nanoparticles synthesized by coastal strains of Escherichia coli and Aspergillus niger

2010 ◽  
Vol 56 (12) ◽  
pp. 1050-1059 ◽  
Author(s):  
Kandasamy Kathiresan ◽  
Nabeel M. Alikunhi ◽  
SriMahibala Pathmanaban ◽  
Asmathunisha Nabikhan ◽  
Saravanakumar Kandasamy
Keyword(s):  
Escherichia Coli ◽  
Silver Nanoparticles ◽  
Aspergillus Niger ◽  
Electrophoretic Analysis ◽  
Protein Band ◽  
Mangrove Sediment ◽  
Diffraction Spectrum ◽  
E Coli ◽  
Extracellular Biosynthesis ◽  
20 Nm

The present study investigated the extracellular biosynthesis of antimicrobial silver nanoparticles by Escherichia coli AUCAS 112 and Aspergillus niger AUCAS 237 derived from coastal mangrove sediment of southeast India. Both microbial species were able to produce silver nanoparticles, as confirmed by X-ray diffraction spectrum. The nanoparticles synthesized were mostly spherical, ranging in size from 5 to 20 nm for E. coli and from 5 to 35 nm for A. niger, as evident by transmission electron microscopy. Fourier transform spectroscopy revealed prominent peaks corresponding to amides I and II, indicating the presence of a protein for stabilizing the nanoparticles. Electrophoretic analysis revealed the presence of a prominent protein band with a molecular mass of 45 kDa for E. coli and 70 kDa for A. niger. The silver nanoparticles inhibited certain clinical pathogens, with antibacterial activity being more distinct than antifungal activity. The antimicrobial activity of E. coli was more pronounced than that of A. niger and was enhanced with the addition of polyvinyl alcohol as a stabilizing agent. This work highlighted the possibility of using microbes of coastal origin for synthesis of antimicrobial silver nanoparticles.

scholarly journals Effect of Optimization Factors on the Production of Bacillus subtilis and Escherichia coli Synthesized Silver Nanoparticles

2021 ◽  
pp. 39-47
Author(s):  
C. Chi-Nwankwo ◽  
J. N. Ogbulie ◽  
C. O. Akujobi
Keyword(s):  
Escherichia Coli ◽  
Silver Nanoparticles ◽  
Bacillus Subtilis ◽  
Negative Slope ◽  
Sharp Decline ◽  
Temperature Variations ◽  
E Coli ◽  
Extracellular Biosynthesis ◽  
Exponential Increase ◽  
Standard Procedures

The recent discovery of silver nanoparticles and their production from Bacillus subtilis and Escherichia coli have enhanced optimization attempts. Extracellular biosynthesis of silver nanoparticles using the Bacillus subtilis and Escherichia coli cultured supernatants was done according to standard procedures. Optimization of the production of silver nanoparticles was done in a 3 X 3 (three factors) design involving temperature (25, 30 and 35 degrees), pH (6, 7 and 8), and time of incubation (24, 48 and 72 Hours) in a total of 15 non-randomized runs. The result showed a sharp decline in the synthesis of B. subtilis silver nanoparticles (BNP) within the first 40 hours but attained steady optimization between 40 – 60 mins. An exponential increase in BNP synthesis was observed between pH 6 – 7 with a slight decline observed between pH 7 – 8. An increase in temperature from 25-300C resulted in a decrease in the production of BNP while the production of BNP increased over 30-350C. An initial lag in Escherichia coli synthesized silver nanoparticle (ENP) synthesis was observed with temperature variations. ENP synthesis maintained an exponential increase up to pH 7 but decreased with 7>pH≤8. The results showed that the increase in temperature resulted in a gradual decrease in production of ENP producing a negative slope. Therefore, the variations in optimization factors of silver nanoparticles produced from both B. subtilis and E. coli led to improved production.

Antimicrobial Activity of Silver Nanoparticles Prepared Under an Ultrasonic Field

2011 ◽  
Vol 4 (3) ◽  
pp. 1491-1496
Author(s):  
Umadevi M ◽  
Rani T ◽  
Balakrishnan T ◽  
Ramanibai R
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Activity ◽  
Silver Nanoparticles ◽  
Reduction Method ◽  
Therapeutic Potential ◽  
Chemical Reduction ◽  
Ultrasonic Field ◽  
Great Promise ◽  
Chemical Reduction Method ◽  
E Coli

Nanotechnology has great promise for improving the therapeutic potential of medicinal molecules and related agents. In this study, silver nanoparticles of different sizes were synthesized in an ultrasonic field using the chemical reduction method with sodium borohydride as a reducing agent. The size effect of silver nanoparticles on antimicrobial activity were tested against the microorganisms Staphylococcus aureus (MTCC No. 96), Bacillus subtilis (MTCC No. 441), Streptococcus mutans (MTCC No. 497), Escherichia coli (MTCC No. 739) and Pseudomonas aeruginosa (MTCC No. 1934). The results shows that B. subtilis, and E. coli were more sensitive to silver nanoparticles and its size, indicating the superior antimicrobial efficacy of silver nanoparticles. 

scholarly journals Transcriptome analysis of Escherichia coli K1 after therapy with hesperidin conjugated with silver nanoparticles

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Abdulkader Masri ◽  
Naveed Ahmed Khan ◽  
Muhammad Zarul Hanifah Md Zoqratt ◽  
Qasim Ayub ◽  
Ayaz Anwar ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Silver Nanoparticles ◽  
Minimum Inhibitory Concentration ◽  
Inhibitory Concentration ◽  
Neonatal Meningitis ◽  
E Coli ◽  
Drug Candidates ◽  
Metabolic Genes ◽  
Genetic Mechanisms ◽  
Cell Stress Response

Abstract Backgrounds Escherichia coli K1 causes neonatal meningitis. Transcriptome studies are indispensable to comprehend the pathology and biology of these bacteria. Recently, we showed that nanoparticles loaded with Hesperidin are potential novel antibacterial agents against E. coli K1. Here, bacteria were treated with and without Hesperidin conjugated with silver nanoparticles, and silver alone, and 50% minimum inhibitory concentration was determined. Differential gene expression analysis using RNA-seq, was performed using Degust software and a set of genes involved in cell stress response and metabolism were selected for the study. Results 50% minimum inhibitory concentration with silver-conjugated Hesperidin was achieved with 0.5 μg/ml of Hesperidin conjugated with silver nanoparticles at 1 h. Differential genetic analysis revealed the expression of 122 genes (≥ 2-log FC, P< 0.01) in both E. coli K1 treated with Hesperidin conjugated silver nanoparticles and E. coli K1 treated with silver alone, compared to untreated E. coli K1. Of note, the expression levels of cation efflux genes (cusA and copA) and translocation of ions, across the membrane genes (rsxB) were found to increase 2.6, 3.1, and 3.3- log FC, respectively. Significant regulation was observed for metabolic genes and several genes involved in the coordination of flagella. Conclusions The antibacterial mechanism of nanoparticles maybe due to disruption of the cell membrane, oxidative stress, and metabolism in E. coli K1. Further studies will lead to a better understanding of the genetic mechanisms underlying treatment with nanoparticles and identification of much needed novel antimicrobial drug candidates.

Green synthesis of silver nanoparticles: Antimicrobial potential and chemosensing of a mutagenic drug nitrofurazone in real samples

Measurement ◽  
2021 ◽  
pp. 109489
Author(s):  
Shah Rizwan Ahmed ◽  
Humera Anwar ◽  
Syed Waseem Ahmed ◽  
Muhammed Raza Shah ◽  
Ayaz Ahmed ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Green Synthesis ◽  
Real Samples ◽  
Antimicrobial Potential

scholarly journals Evaluation of Changes Induced in the Probiotic Escherichia coli M17 Following Recurrent Exposure to Antimicrobials

2021 ◽  
pp. 158-167
Author(s):  
M. J. A. Mbarga ◽  
I. V. Podoprigora ◽  
E. G. Volina ◽  
A. V. Ermolaev ◽  
L. A. Smolyakova
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Silver Nanoparticles ◽  
Biofilm Formation ◽  
Fold Increase ◽  
Bacterial Attachment ◽  
Diffusion Method ◽  
Cross Resistance ◽  
Microdilution Method ◽  
Similar Work

Introduction: It is already well known that the exposure of certain bacteria, pathogenic or not, to antimicrobials is likely to increase their virulence and induce the development of direct or cross resistance to antimicrobials, but there is almost no information available regarding probiotics. Aim: To assess the changes induced in susceptibility to antibiotics, biofilm formation, growth rate and relative pathogenicity in the probiotic Escherichia coli M17 (EC-M17) after long exposure to antimicrobials namely ampicillin, kanamycin, cefazolin and silver nanoparticles (AgNPs). Methods: After determining the minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) of the 4 antimicrobials above-mentioned by the microdilution method, EC-M17 was exposed to increasing subinhibitory doses ranging from MIC/8 to MIC for 8 days. The susceptibility to antibiotics of the mutants obtained was assessed by the Kirby Bauer disc diffusion method, biofilm formation by the Congo red agar method and with crystal violet bacterial attachment assay, and relative pathogenicity was assessed using a Galleria melonella waxworm model. Results: Exposure to antimicrobials induces noticeable changes in EC-M17. The highest adaptation to antimicrobials was observed on AgNPs with 8-fold increase in MIC and 16-fold increase in MBC of AgNPs. EC-M17 exposed to ampicillin, kanamycin and silver nanoparticles became resistant to ampicillin, ceftazidime, ceftazidime/clavulanate and tetracycline while exposure to cefazolin induced a significant decrease in sensitivity to tetracycline and ampicillin and resistance to ceftazidime/clavulanate and ceftazidime. The strain exposed to ampicillin was the only one to produce more biofilm than the control strain and except the EC-M17 exposed to cefazolin, all other EC-M17 strains were more pathogenic on G. melonella model than the control. Conclusion: Data in this investigation suggest that repeated exposure of the probiotic EC-M17 to antimicrobials may induce changes in antimicrobials susceptibility, biofilm formation, growth rate, and relative pathogenicity. Therefore, as far as possible, the probiotic E. coli M17 should not be used in combination with antibiotics and further investigations are required to expand similar work on more probiotics in order to avoid resistance build-up which might be transmitted by horizontal transfer.

Guanidinium and phosphonium scaffolds loaded with silver nanoparticles: synthesis, characterization, in vitro assessment of the antibacterial potential and toxicity

2021 ◽  
Author(s):  
M. N. Gorbunova ◽  
L.M. Lemkina ◽  
A.I. Nechaev
Keyword(s):  
Escherichia Coli ◽  
Silver Nanoparticles ◽  
Uv Spectroscopy ◽  
Planktonic Cells ◽  
Silver Nanocomposites ◽  
Nanoparticles Synthesis ◽  
In Vitro Assessment ◽  
Xrd Techniques ◽  
Antibacterial Potential

Abstract New silver nanocomposites based on polysulfones of 2,2-diallyl-1,1,3,3-tetraethylguanidiniumchloride [poly(AGC-SO2)], tris(diethylamino)diallylaminophosphonium tetrafluoroborate [poly(DAAP-BF4-SO2)] and chloride [poly(DAAP-Cl-SO2)] have been developed. UV- spectroscopy, SEM and XRD techniques were used to characterize the formation of silver nanoparticles in copolymers. Antibacterial action of new silver nanocomposites on S. epidermidis 33 and Escherichia coli (planktonic cells and biofilms) was studied. The silver nanocomposites strongly inhibited biofilms formation of S. epidermidis 33 and Escherichia coli. The silver nanocomposites based on phosphonium polysulfones have a significant cytotoxic activity against RD and MS line cells.

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