scholarly journals Biofilm Eradication Using Biogenic Silver Nanoparticles

Molecules ◽  
2020 ◽  
Vol 25 (9) ◽  
pp. 2023 ◽  
Author(s):  
María Belén Estevez ◽  
Sofía Raffaelli ◽  
Scott G. Mitchell ◽  
Ricardo Faccio ◽  
Silvana Alborés
Keyword(s):  
Silver Nanoparticles ◽  
Colloidal Stability ◽  
Fatty Acid Content ◽  
Membrane Integrity ◽  
Antimicrobial Properties ◽  
Value Added ◽  
Industrial Applications ◽  
Bioactive Substances ◽  
Cell Membrane Integrity ◽  
E Coli

Microorganisms offer an alternative green and scalable technology for the synthesis of value added products. Fungi secrete high quantities of bioactive substances, which play dual-functional roles as both reducing and stabilizing agents in the synthesis of colloidal metal nanoparticles such as silver nanoparticles, which display potent antimicrobial properties that can be harnessed for a number of industrial applications. The aim of this work was the production of silver nanoparticles using the extracellular cell free extracts of Phanerochaete chrysosporium, and to evaluate their activity as antimicrobial and antibiofilm agents. The 45–nm diameter silver nanoparticles synthesized using this methodology possessed a high negative surface charge close to −30 mV and showed colloidal stability from pH 3–9 and under conditions of high ionic strength ([NaCl] = 10–500 mM). A combination of environmental SEM, TEM, and confocal Raman microscopy was used to study the nanoparticle-E. coli interactions to gain a first insight into their antimicrobial mechanisms. Raman data demonstrate a significant decrease in the fatty acid content of E. coli cells, which suggests a loss of the cell membrane integrity after exposure to the PchNPs, which is also commensurate with ESEM and TEM images. Additionally, these biogenic PchNPs displayed biofilm disruption activity for the eradication of E. coli and C. albicans biofilms.

scholarly journals Low-Level Organic Solvents Improve Multienzyme Whole-Cell Catalytic Synthesis of Myricetin-7-O-Glucuronide

Catalysts ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 970 ◽  
Author(s):  
Yan Yang ◽  
Min-Zhi Liu ◽  
Yun-Song Cao ◽  
Chang-Kun Li ◽  
Wei Wang
Keyword(s):  
Cell Membrane ◽  
Organic Solvents ◽  
Membrane Integrity ◽  
Industrial Applications ◽  
Coli Strain ◽  
Whole Cell ◽  
Cell Membrane Integrity ◽  
E Coli ◽  
Low Level ◽  
Whole Cell Catalysis

Multienzyme whole-cell biocatalysts are preferred in industrial applications, and two major concerns regarding the use of these biocatalysts, cell viability and cell membrane integrity, must be addressed. In this work, the transformation of myricetin to myricetin-7-O-glucuronide catalyzed by an engineered Escherichia coli strain was taken as the model reaction to examine the impacts of low-level organic solvents on whole-cell biocatalysis. Low-level organic solvents (2%, v/v) showed a significant increase (roughly 13-fold) in myricetin-7-O-glucuronide yields. No obvious compromises of cellular viability and integrity were observed by a flow cytometry assay or in the determination of extracellular protein leakage, suggesting the addition of low-level organic solvents accommodates whole E. coli cells. Furthermore, a scaled-up reaction was conducted to test the capability and efficiency of whole-cell catalysis in the presence of organic solvents. This study presents a promising and simple means to enhance the productivity of multienzyme whole-cell catalysis without losing the barrier functions of the cell membrane.

scholarly journals Biogenic Silver Nanoparticles Conjugated with Nisin: Improving the Antimicrobial and Antibiofilm Properties of Nanomaterials

Chemistry ◽  
2021 ◽  
Vol 3 (4) ◽  
pp. 1271-1285
Author(s):  
Patricia Zimet ◽  
Ruby Valadez ◽  
Sofía Raffaelli ◽  
María Belén Estevez ◽  
Helena Pardo ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Antimicrobial Properties ◽  
Value Added ◽  
Green Technology ◽  
Natural Food ◽  
Antibiofilm Activity ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Biogenic Silver Nanoparticles

Microbial technology offers a green alternative for the synthesis of value-added nanomaterials. In particular, fungal compounds can improve silver nanoparticle production, stabilizing colloidal nanoparticles. Based on a previous study by our group, silver nanoparticles obtained using the extracellular cell-free extracts of Phanerochaete chrysosporium (PchNPs) have shown antimicrobial and antibiofilm activity against Gram-negative bacteria. Moreover, nisin—a bacteriocin widely used as a natural food preservative—has recently gained much attention due its antimicrobial action against Gram-positive bacteria in biomedical applications. Therefore, the aim of this work was to conjugate biogenic silver nanoparticles (PchNPs) with nisin to obtain nanoconjugates (PchNPs@nis) with enhanced antimicrobial properties. Characterization assays were conducted to determine physicochemical properties of PchNPs@nis, and also their antibacterial and antibiofilm activities were studied. The formation of PchNPs@nis was confirmed by UV-Vis, TEM, and Raman spectroscopy analysis. Different PchNPs@nis nanobioconjugates showed diameter values in the range of 60–130 nm by DLS and surface charge values between −20 and −13 mV. Nisin showed an excellent affinity to PchNPs, with binding efficiencies higher than 75%. Stable synthesized PchNPs@nis nanobioconjugates were not only able to inhibit biofilm formation by S. aureus, but also showed inhibition of the planktonic cell growth of Staphyloccocus aureus and Escherichia coli, broadening the spectrum of action of the unconjugated antimicrobials against Gram-positive and Gram-negative bacteria. In conclusion, these results show the promising application of PchNPs@nis, prepared via green technology, as potential antimicrobial nanomaterials.

scholarly journals Bacterial plasma membrane is the main cellular target of silver nanoparticles in Escherichia coli and Pseudomonas aeruginosa

2018 ◽  
Author(s):  
Olesja M Bondarenko ◽  
Mariliis Sihtmäe ◽  
Julia Kuzmičiova ◽  
Lina Ragelienė ◽  
Anne Kahru ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Silver Nanoparticles ◽  
Plasma Membrane ◽  
Antimicrobial Properties ◽  
Consumer Products ◽  
Minimal Bactericidal Concentration ◽  
Flow Cytometry Analysis ◽  
E Coli ◽  
Cellular Target

ABSTRACTSilver nanoparticles (AgNP) are widely used in consumer products, mostly due to their excellent antimicrobial properties. One of the well-established antibacterial mechanisms of AgNP is their efficient contact with bacteria and dissolution on cell membranes. To our knowledge, the primary mechanism of cell wall damage and the event(s) initiating bactericidal action of AgNP are not yet elucidated.In this study we used a combination of different assays to reveal the effect of AgNP on i) bacterial envelope in general, ii) outer membrane (OM) and iii) on plasma membrane (PM). We showed that bacterial PM was the main target of AgNP in Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa. AgNP depolarized bacterial PM, induced the leakage of the intracellular K+, inhibited respiration and caused the depletion of the intracellular ATP. In contrast, AgNP had no significant effect on the bacterial OM. Most of the adverse effects on bacterial envelope and PM occurred within the seconds and in the concentration range of 7-160 μM AgNP, depending on the bacteria and assay used, while irreversible inhibition of bacterial growth (minimal bactericidal concentration after 1-h exposure of bacteria to AgNP) occurred at 40 μM AgNP for P. aeruginosa and at 320 μM AgNP for E. coli.Flow cytometry analysis showed that AgNP were binding to P. aeruginosa but not to E. coli cells and were found inside the P. aeruginosa cells. Taking into account that AgNP did not damage OM, we speculate that AgNP entered P. aeruginosa via specific mechanism, e.g., transport through porins.

scholarly journals Evaluation of the Antimicrobial Effect of the Extracts of the Pods of Piliostigma thonningii (Schumach.) Milne-Redh. (Fabaceae)

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Memory Makosa ◽  
Simbarashe Sithole ◽  
Stanley Mukanganyama
Keyword(s):  
Antimicrobial Agents ◽  
Membrane Integrity ◽  
Herbal Medicines ◽  
Antimicrobial Properties ◽  
Fine Powder ◽  
Ethanol Extract ◽  
Antimicrobial Effects ◽  
Cell Membrane Integrity ◽  
Successive Extraction ◽  
Piliostigma Thonningii

Plants have been used traditionally by people in treating and the management of diseases since time immemorial. Traditional medicines including the herbal medicines are used for primary healthcare in some domains in almost every country. Approximately 80% of the population in developing coutries depend on plants as their source of medicine for combating diseases. New and effective antimicrobial agents that have novel mechanism of actions are required. Piliostigma thonningii (Schumach.) Milne-Redh. is a species of flowering plants in the legume family, Fabaceae. Different parts of the P. thonningii plants such as the roots, leaves, seeds, and fruits have been used in treating wounds, heart pain, and gingivitis and as cough remedy. This study focused on determining the antimicrobial properties found in the pods of P. thonningii. The sample was prepared by grinding the dried pods into a fine powder. Successive extraction and extraction with 1 : 1 DCM: methanol was used. The antimicrobial assay was carried out using the broth microdilution and MTT assay. The microorganism used for the tests was Pseudomonas aeruginosa, Candida krusei and Mycobacterium smegmatis. The most potent extract was then used to determine its effect on microbial cell membrane integrity. The results showed that methanol extract had the highest percentage yield of 5%. The extract with the highest antimicrobial effects was ethanol extract with the 100 μg/mL concentration inhibiting the growth of cells to 26%, 87%, and 90% for P. aeruginosa, M. smegmatis, and C. krusei, respectively. The ethanol extracts caused significant leakage of proteins in these microorganisms. In conclusion, the pods of P. thonningii contain phytochemicals with antimicrobial properties. The pods of the plant can be a source of phytochemicals that can serve as sources of lead compounds with antimicrobial effects. One of the mechanisms of action of these phytochemicals is via membrane-damaging effects on microbes.

scholarly journals Effects of silver nanoparticles of different sizes on cytotoxicity and oxygen metabolism disorders in both reproductive and respiratory system cells

2016 ◽  
Vol 42 (4) ◽  
pp. 32-47 ◽  
Author(s):  
Lidia Zapór
Keyword(s):  
Silver Nanoparticles ◽  
Oxidative Dna Damage ◽  
Antimicrobial Agents ◽  
Membrane Integrity ◽  
Oxygen Metabolism ◽  
Protective Measures ◽  
Cytotoxic Effects ◽  
Cell Membrane Integrity ◽  
Antioxidative Status ◽  
Low Concentrations

Abstract Silver nanoparticles (AgNPs) are widely used in numerous industries and areas of daily life, mainly as antimicrobial agents. The particles size is very important, but still not suffi ciently recognized parameter infl uencing the toxicity of nanosilver. The aim of this study was to investigate the cytotoxic effects of AgNPs with different particle size (~ 10, 40 and 100 nm). The study was conducted on both reproductive and pulmonary cells (CHO-9, 15P-1 and RAW264.7). We tested the effects of AgNPs on cell viability, cell membrane integrity, mitochondrial metabolic activity, lipid peroxidation, total oxidative and antioxidative status of cells and oxidative DNA damage. All kinds of AgNPs showed strong cytotoxic activity at low concentrations (2÷13 μg/ml), and caused an overproduction of reactive oxygen species (ROS) at concentrations lower than cytotoxic ones. The ROS being formed in the cells induced oxidative damage of DNA in alkaline comet assay. The most toxic was AgNPs<10 nm. The results indicate that the silver nanoparticles, especially less than 10 nm, may be harmful to the organisms. Therefore, risk should be considered when using nanosilver preparations and provide appropriate protective measures when they are applied.

Characterization and antibacterial properties of Eriobotrya japonica extract loaded silver-nanoparticles

2020 ◽  
Vol 16 ◽  
Author(s):  
Arfaa Sajid ◽  
Qaisar Manzoor ◽  
Anam Sajid ◽  
Muhammad Imran ◽  
Shanza Khalid ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Green Synthesis ◽  
Antibacterial Properties ◽  
Antimicrobial Properties ◽  
Silver Ions ◽  
Eriobotrya Japonica ◽  
X Ray Diffraction ◽  
Effective Utilization ◽  
E Coli ◽  
Elongated Nanoparticles

Background:: Currently, developing methods for the formation of nanoparticles with antimicrobial properties based on green chemistry are the research hotspots. In this research green biosynthesis of Eriobotrya japonica extract loaded silver nanoparticles and their characterization were the main objectives to achieve. Methods:: Green synthesis of E. japonica leaves extract-loaded silver nanoparticles (AgNPs) was carried out and its effect on bacterial growth was examined. The reduction of silver ions in solution was observed using UV-Vis spectrophotometer. The properties of AgNPs were assessed using Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Also, their antibacterial effects were checked against Staphylococcus aureus and Escherichia coli. Results:: It was revealed that 5-50 nm sized spherical to elongated nanoparticles were synthesized that possessed comparatively better antibacterial potential against E. coli and S. aureus than conventional extract of the E. japonica leaves. Conclusions:: Green synthesis and effective utilization of Eriobotrya japonica extract loaded silver nanoparticles is a promising approach for nanoparticle production avoiding negative environmental impacts.

Nitrification inhibition by silver nanoparticles

2009 ◽  
Vol 59 (9) ◽  
pp. 1699-1702 ◽  
Author(s):  
O. K. Choi ◽  
Z. Q. Hu
Keyword(s):  
Silver Nanoparticles ◽  
Wastewater Treatment ◽  
Wastewater Treatment Plants ◽  
Silver Chloride ◽  
Membrane Integrity ◽  
Silver Ions ◽  
Nitrifying Bacteria ◽  
Nitrification Inhibition ◽  
Cell Membrane Integrity ◽  
Sulfide Species

Nitrification inhibition by silver nanoparticles (nanosilver) was evaluated by extant respirometry using enriched nitrifying bacteria isolated from wastewater treatment plants. Silver nanoparticles were more toxic than silver ions or silver chloride colloids, all of which did not disrupt cell membrane integrity at 1 mg/L Ag. The toxicity of silver nanoparticles was reduced in the presence of various anions, especially sulfide. The results suggest that silver nanoparticles have the same behaviour of surface complexation as silver ions, and inhibition by nanosilver in wastewater treatment may be removed by reaction of silver nanoparticles with soluble sulfide species.

scholarly journals Effect of Farnesol on Staphylococcus aureus Biofilm Formation and Antimicrobial Susceptibility

2006 ◽  
Vol 50 (4) ◽  
pp. 1463-1469 ◽  
Author(s):  
M. A. Jabra-Rizk ◽  
T. F. Meiller ◽  
C. E. James ◽  
M. E. Shirtliff
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Antimicrobial Agents ◽  
Membrane Integrity ◽  
Antimicrobial Properties ◽  
Bloodstream Infections ◽  
High Concentration ◽  
Bacterial Populations ◽  
Cell Membrane Integrity ◽  
Plate Counts

ABSTRACT Staphylococcus aureus is among the leading pathogens causing bloodstream infections able to form biofilms on host tissue and indwelling medical devices and to persist and cause disease. Infections caused by S. aureus are becoming more difficult to treat because of increasing resistance to antibiotics. In a biofilm environment particularly, microbes exhibit enhanced resistance to antimicrobial agents. Recently, farnesol was described as a quorum-sensing molecule with possible antimicrobial properties. In this study, the effect of farnesol on methicillin-resistant and -susceptible strains of S. aureus was investigated. With viability assays, biofilm formation assessment, and ethidium bromide uptake testing, farnesol was shown to inhibit biofilm formation and compromise cell membrane integrity. The ability of farnesol to sensitize S. aureus to antimicrobials was assessed by agar disk diffusion and broth microdilution methods. For both strains of staphylococci, farnesol was only able to reverse resistance at a high concentration (150 μM). However, it was very successful at enhancing the antimicrobial efficacy of all of the antibiotics to which the strains were somewhat susceptible. Therefore, synergy testing of farnesol and gentamicin was performed with static biofilms exposed to various concentrations of both agents. Plate counts of harvested biofilm cells at 0, 4, and 24 h posttreatment indicated that the combined effect of gentamicin at 2.5 times the MIC and farnesol at 100 μM (22 μg/ml) was able to reduce bacterial populations by more than 2 log units, demonstrating synergy between the two antimicrobial agents. This observed sensitization of resistant strains to antimicrobials and the observed synergistic effect with gentamicin indicate a potential application for farnesol as an adjuvant therapeutic agent for the prevention of biofilm-related infections and promotion of drug resistance reversal.

scholarly journals Preparation of antibacterial polypropylene grafted acrylic acid and immobilized silver nanoparticles by γ-irradiation method

2018 ◽  
Vol 14 (4) ◽  
pp. 699-704
Author(s):  
Dang Hoang Viet ◽  
Duong Hoa Xo ◽  
Le Quang Luan
Keyword(s):  
Silver Nanoparticles ◽  
Acrylic Acid ◽  
Mammalian Cells ◽  
Antibacterial Properties ◽  
Antimicrobial Properties ◽  
Inhibition Zone ◽  
Γ Irradiation ◽  
E Coli ◽  
Γ Rays

Silver nanoparticles (AgNPs) are now being widely used as antibacterial agents due to their strong bactericidal properties and low toxicity on mammalian cells. In this study, γ-rays irradiation method was used to synthesize AgNPs from silver nitrate (AgNO3) solution and to graft acrylic acid (AAc) onto porous polypropylene (PP). Porous PP grafted with AAc (PP-g-AAc) was then immobilized with AgNPs for preparing the antimicrobial materials (PP-g-AAc/AgNPs). The results demonstrated that the grafting yield of AAc onto PP increased by the increasing of irradiation dose as well as AAc concentration. The PP-g-AAc samples with grafting degrees from 1.2 to 29.8% were immobilized with AgNPs (d ~ 10 nm, 500 ppm) to obtain antimicrobial properties. The immobilized Ag contents were from 132 to 392 ppm and corresponded to the PP-g-AAc samples at grafting degrees from 1.2 to 29.8%. The in vitro antibacterial properties of PP-g-AAc/AgNPs materials on E. coli were evaluated and the results indicated that the bactericidal efficiency (η) increased by the increase of Ag contents in the tested materials. The germicidal activities against E. coli of PP-g-AAc/AgNPs containing 363 ppm Ag were found to be nearly 100% after treating in 30 min. In addition, the inhibition zone of this PP-g-AAc/AgNPs on E. coli was also found up to 28 mm in diameter. Thus, γ-rays radiation demonstrated a strong capability in grafting functional groups (AAc) onto porous PP. Furthermore, the porous PP grafted with AAc and immobilized with AgNPs might potentially be used for elimination of bacteria in water filtering.

scholarly journals Cloning, expression and characterization of a chitinase from Paenibacillus chitinolyticus strain UMBR 0002

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8964 ◽  
Author(s):  
Cong Liu ◽  
Naikun Shen ◽  
Jiafa Wu ◽  
Mingguo Jiang ◽  
Songbiao Shi ◽  
...  
Keyword(s):  
Genomic Library ◽  
Specific Activity ◽  
Sodium Dodecyl ◽  
Value Added ◽  
Industrial Applications ◽  
Degree Of Polymerization ◽  
Colloidal Chitin ◽  
Target Sequence ◽  
E Coli ◽  
Low Efficiency

Background Chitinases are enzymes which degrade β-1,4-glycosidid linkages in chitin. The enzymatic degradation of shellfish waste (containing chitin) to chitooligosaccharides is used in industrial applications to generate high-value-added products from such waste. However, chitinases are currently produced with low efficiency and poor tolerance, limiting the industrial utility. Therefore, identifying chitinases with higher enzymatic activity and tolerance is of great importance. Methods Primers were designed using the genomic database of Paenibacillus chitinolyticus NBRC 15660. An exochitinase (CHI) was cloned into the recombinant plasmid pET-22b (+) to form pET-22b (+)-CHI, which was transformed into Escherichia coli TOP10 to construct a genomic library. Transformation was confirmed by colony-polymerase chain reaction and electrophoresis. The target sequence was verified by sequencing. Recombinant pET-22b (+)-CHI was transformed into E. coli Rosetta-gami B (DE3) for expression of chitinase. Recombinant protein was purified by Ni-NTA affinity chromatography and enzymatic analysis was carried out. Results The exochitinase CHI from P. chitinolyticus strain UMBR 0002 was successfully cloned and heterologously expressed in E. coli Rosetta-gami B (DE3). Purification yielded a 13.36-fold enrichment and recovery yield of 72.20%. The purified enzyme had a specific activity of 750.64 mU mg−1. The optimum pH and temperature for degradation of colloidal chitin were 5.0 and 45 °C, respectively. The enzyme showed high stability, retaining >70% activity at pH 4.0–10.0 and 25–45 °C (maximum of 90 min). The activity of CHI strongly increased with the addition of Ca2+, Mn2+, Tween 80 and urea. Conversely, Cu2+, Fe3+, acetic acid, isoamyl alcohol, sodium dodecyl sulfate and β-mercaptoethanol significantly inhibited enzyme activity. The oligosaccharides produced by CHI from colloidal chitin exhibited a degree of polymerization, forming N-acetylglucosamine (GlcNAc) and (GlcNAc)2 as products. Conclusions This is the first report of the cloning, heterologous expression and purification of a chitinase from P. chitinolyticus strain UMBR 0002. The results highlight CHI as a good candidate enzyme for green degradation of chitinous waste.

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