scholarly journals ZnO Nanoparticles-Chitosan Composite as Antibacterial Finish for Textiles

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Asmaa Farouk ◽  
Shaaban Moussa ◽  
Mathias Ulbricht ◽  
Torsten Textor
Keyword(s):  
Escherichia Coli ◽  
Antibacterial Activity ◽  
Zno Nanoparticles ◽  
Micrococcus Luteus ◽  
Sol Gel ◽  
Negative Bacterium ◽  
Hybrid Polymers ◽  
Gram Negative ◽  
Organic Hybrid ◽  
Equal Degree

The antibacterial performance of sol-gel-derived inorganic-organic hybrid polymers filled with ZnO nanoparticles-chitosan against a gram-negative bacterium Escherichia coli and a gram-positive Micrococcus luteus has been investigated. Three different molecular weights (MW) of chitosan (CTS) 1.36 · 105, 2.2 · 105, and 3.0 · 105 Da with equal degree of deacetylation (DD, 85%) (coded as S 85-60, He 85-250, and He 85-500) with equal degree of deacetylation (DD, 85%) were examined. ZnO was prepared by the base hydrolysis of zinc acetate in isopropanol using lithium hydroxide (LiOH · H2O) to hydrolyze the precursor. Sol-gel-based inorganic-organic hybrid polymers were modified with these oxides and were applied to cellulosic cotton (100%) and cotton/polyester (65/35%) fabrics. Inorganic-organic hybrids polymers were based on 3-glycidyloxypropyltrimethoxysilane (GPTMS). Bacteriological tests were performed in nutrient agar media on solid agar plates and in liquid broth systems using ZnO nanoparticles with average particle size of (40 nm). Our study showed the enhanced antibacterial activity of ZnO nanoparticles chitosan (different MW) of against a gram-negative bacterium Escherichia coli DSMZ 498 and a gram-positive Micrococcus luteus ATCC 9341 in repeated experiments. The antibacterial activity of textile treated with ZnO nanoparticles chitosan increases with decreasing the molecular weight of chitosan.

scholarly journals Antimicrobial Activity of Extracts and Fractions from Aerial Parts of Selected Plants (Garcinia achachairu, Macrosiphonia velame, Rubus niveus and Pilea microphylla) Against Some Pathogenic Microorganisms

2013 ◽  
Vol 8 (11) ◽  
pp. 1934578X1300801 ◽  
Author(s):  
Carla Melim ◽  
Karoliny Guimarães ◽  
Zhelmy Martin-Quintal ◽  
Aurea Damaceno Alves ◽  
Domingos Tabajara de Oliveira Martins ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antibacterial Activity ◽  
Pathogenic Microorganisms ◽  
Negative Bacterium ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Aerial Parts ◽  
Brazilian Flora ◽  
Brazilian Biodiversity

As part of the program of our research group to search for new and effective substances from the Brazilian biodiversity, the present work evaluates the antibacterial activity of four species from the Brazilian flora ( Garcinia achachairu, Macrosiphonia velame, Rubus niveus and Pilea microphylla) against Bacillus subtilis, Staphylococcus aureus and S. saprophyticus (Gram-positive bacteria), Escherichia coli (Gram-negative bacterium) and Candida albicans (yeast). The extracts of R. niveus and M. velame showed promising antibacterial activity with MICs, ranging from 1000 to 125 μg/mL. Bio-guided fractionation of M. velame yielded four compounds, with the highest inhibition being observed for compound 3, with a MIC of 125 μg/mL against S. aureus. The combinations of fractions 2 and 4 showed beneficial effect against Gram-positive bacteria (additive effect), suggesting a possible synergistic effect.

scholarly journals An investigation of the effect of the extracts from the seeds of Bidens pilosa on the growth of Escherichia coli and Bacillus subtilis

2021 ◽  
Vol 4 (1) ◽  
pp. 125-128
Author(s):  
Jordan Johnson ◽  
Lovely Anderson ◽  
Jennifer Laifa
Keyword(s):  
Escherichia Coli ◽  
Antibacterial Activity ◽  
Bacillus Subtilis ◽  
Food Poisoning ◽  
Negative Bacterium ◽  
Bidens Pilosa ◽  
Gram Positive ◽  
Gram Negative ◽  
E Coli ◽  
Zones Of Inhibition

Escherichia coli is a Gram-negative bacterium also found in the human. Bacillus subtilis is a Gram-positive, non-pathogenic, endospore-forming bacterium. The spores can survive the heat and B. subtilis to cause food poisoning. The study hypothesized that the extracts from B. pilosa would inhibit the growth of E. coli and B. subtilis. The seeds of B. pilosa were purchased from the seed company. The seeds were dried, ground, and shaken in acetone, ethanol, methanol, and water for 72 hours. Solvents were evaporated and the crude extracts were used for antibacterial activity using a modified Kirby-Bauer disc method. The results revealed that the growth of E. coli was inhibited by the extracts using ethanol. The zones of inhibition were 13 mm. The extracts that were extracted using acetone and water were not effective in inhibiting the growth of E. coli. The growth of B. subtilis was inhibited by the extracts from acetone and methanol. The zones of inhibition were 13 mm. The results revealed that the extracts from ethanol and water were not effective in inhibiting the growth of B. subtilis. Seeds of B. pilosa have the potential to be used as antimicrobials.

Iso-octenidine: Promising Octenidine Analogue with Improved Solubility

2020 ◽  
Vol 17 ◽  
Author(s):  
Igor K. Yakuschenko ◽  
Nataliya N. Pozdeeva ◽  
Viktoriya A. Mumyatova ◽  
Alexey A. Terentiev ◽  
Svyatoslav Ya. Gadomsky
Keyword(s):  
Escherichia Coli ◽  
Antibacterial Activity ◽  
Micrococcus Luteus ◽  
Octenidine Dihydrochloride ◽  
First Time

: Iso-octenidine, an isomer of octenidine dihydrochloride, was synthesized and studied for the first time. Isooctenidine was demonstrated to be 3-fold more soluble in water in comparison to original octenidine, and both substances had remarkably similar antibacterial activity (tested on Escherichia Coli and Micrococcus luteus).

Synthesis of Chalcones and Nucleosides Incorporating [1, 3, 4]Oxadiazolenone Core and Evaluation of their Antifungal and Antibacterial Activities

2020 ◽  
Vol 15 (6) ◽  
pp. 665-679
Author(s):  
Alok K. Srivastava ◽  
Lokesh K. Pandey
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Bacillus Subtilis ◽  
Antifungal Activity ◽  
Aspergillus Niger ◽  
Gram Negative ◽  
E Coli ◽  
Gram Positive Bacteria ◽  
Good Antibacterial Activity

Background: [1, 3, 4]oxadiazolenone core containing chalcones and nucleosides were synthesized by Claisen-Schmidt condensation of a variety of benzaldehyde derivatives, obtained from oxidation of substituted 5-(3/6 substituted-4-Methylphenyl)-1, 3, 4-oxadiazole-2(3H)-one and various substituted acetophenone. The resultant chalcones were coupled with penta-O-acetylglucopyranose followed by deacetylation to get [1, 3, 4] oxadiazolenone core containing chalcones and nucleosides. Various analytical techniques viz IR, NMR, LC-MS and elemental analysis were used to confirm the structure of the synthesised compounds.The compounds were targeted against Bacillus subtilis, Staphylococcus aureus and Escherichia coli for antibacterial activity and Aspergillus flavus, Aspergillus niger and Fusarium oxysporum for antifungal activity. Methods: A mixture of Acid hydrazides (3.0 mmol) and N, Nʹ- carbonyl diimidazole (3.3 mmol) in 15 mL of dioxane was refluxed to afford substituted [1, 3, 4]-oxadiazole-2(3H)-one. The resulted [1, 3, 4]- oxadiazole-2(3H)-one (1.42 mmol) was oxidized with Chromyl chloride (1.5 mL) in 20 mL of carbon tetra chloride and condensed with acetophenones (1.42 mmol) to get chalcones 4. The equimolar ratio of obtained chalcones 4 and β -D-1,2,3,4,6- penta-O-acetylglucopyranose in presence of iodine was refluxed to get nucleosides 5. The [1, 3, 4] oxadiazolenone core containing chalcones 4 and nucleosides 5 were tested to determined minimum inhibitory concentration (MIC) value with the experimental procedure of Benson using disc-diffusion method. All compounds were tested at concentration of 5 mg/mL, 2.5 mg/mL, 1.25 mg/mL, 0.62 mg/mL, 0.31 mg/mL and 0.15 mg/mL for antifungal activity against three strains of pathogenic fungi Aspergillus flavus (A. flavus), Aspergillus niger (A. niger) and Fusarium oxysporum (F. oxysporum) and for antibacterial activity against Gram-negative bacterium: Escherichia coli (E. coli), and two Gram-positive bacteria: Staphylococcus aureus (S. aureus) and Bacillus subtilis(B. subtilis). Result: The chalcones 4 and nucleosides 5 were screened for antibacterial activity against E. coli, S. aureus and B. subtilis whereas antifungal activity against A. flavus, A. niger and F. oxysporum. Compounds 4a-t showed good antibacterial activity whereas compounds 5a-t containing glucose moiety showed better activity against fungi. The glucose moiety of compounds 5 helps to enter into the cell wall of fungi and control the cell growth. Conclusion: Chalcones 4 and nucleosides 5 incorporating [1, 3, 4] oxadiazolenone core were synthesized and characterized by various spectral techniques and elemental analysis. These compounds were evaluated for their antifungal activity against three fungi; viz. A. flavus, A. niger and F. oxysporum. In addition to this, synthesized compounds were evaluated for their antibacterial activity against gram negative bacteria E. Coli and gram positive bacteria S. aureus, B. subtilis. Compounds 4a-t showed good antibacterial activity whereas 5a-t showed better activity against fungi.

scholarly journals Proteomic response of Escherichia coli to a membrane lytic and iron chelating truncated Amaranthus tricolor defensin

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Tessa B. Moyer ◽  
Ashleigh L. Purvis ◽  
Andrew J. Wommack ◽  
Leslie M. Hicks
Keyword(s):  
Escherichia Coli ◽  
Antibacterial Activity ◽  
Antimicrobial Peptides ◽  
Mechanism Of Action ◽  
Gram Negative Bacteria ◽  
Amaranthus Tricolor ◽  
Core Motif ◽  
Gram Negative ◽  
E Coli ◽  
Membrane Lysis

Abstract Background Plant defensins are a broadly distributed family of antimicrobial peptides which have been primarily studied for agriculturally relevant antifungal activity. Recent studies have probed defensins against Gram-negative bacteria revealing evidence for multiple mechanisms of action including membrane lysis and ribosomal inhibition. Herein, a truncated synthetic analog containing the γ-core motif of Amaranthus tricolor DEF2 (Atr-DEF2) reveals Gram-negative antibacterial activity and its mechanism of action is probed via proteomics, outer membrane permeability studies, and iron reduction/chelation assays. Results Atr-DEF2(G39-C54) demonstrated activity against two Gram-negative human bacterial pathogens, Escherichia coli and Klebsiella pneumoniae. Quantitative proteomics revealed changes in the E. coli proteome in response to treatment of sub-lethal concentrations of the truncated defensin, including bacterial outer membrane (OM) and iron acquisition/processing related proteins. Modification of OM charge is a common response of Gram-negative bacteria to membrane lytic antimicrobial peptides (AMPs) to reduce electrostatic interactions, and this mechanism of action was confirmed for Atr-DEF2(G39-C54) via an N-phenylnaphthalen-1-amine uptake assay. Additionally, in vitro assays confirmed the capacity of Atr-DEF2(G39-C54) to reduce Fe3+ and chelate Fe2+ at cell culture relevant concentrations, thus limiting the availability of essential enzymatic cofactors. Conclusions This study highlights the utility of plant defensin γ-core motif synthetic analogs for characterization of novel defensin activity. Proteomic changes in E. coli after treatment with Atr-DEF2(G39-C54) supported the hypothesis that membrane lysis is an important component of γ-core motif mediated antibacterial activity but also emphasized that other properties, such as metal sequestration, may contribute to a multifaceted mechanism of action.

Efficacy of crude extracts of Clitoria ternatea for antibacterial activity against gram negative bacterium (Proteus mirabilis)

2019 ◽  
Vol 21 ◽  
pp. 101328 ◽  
Author(s):  
S. Dhanasekaran ◽  
A. Rajesh ◽  
Thangavel Mathimani ◽  
S. Melvin Samuel ◽  
Rajasree Shanmuganathan ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Proteus Mirabilis ◽  
Negative Bacterium ◽  
Gram Negative ◽  
Clitoria Ternatea ◽  
Crude Extracts

scholarly journals A New Prenylated Flavanoid with Antibacterial Activity from Propolis Collected in Egypt

2010 ◽  
Vol 5 (1) ◽  
pp. 1934578X1000500 ◽  
Author(s):  
Ashraf El-Bassuony ◽  
Sameh AbouZid
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Bacillus Cereus ◽  
Spectroscopic Methods ◽  
Gram Positive ◽  
Gram Negative

A novel prenylated flavanoid, isonymphaeol-D (1), together with two known compounds, isonymphaeol-B (2) and nymphaeol-B (3), were isolated from Egyptian propolis. The structures of the isolated compounds were determined by various spectroscopic methods. 1 exhibited antibacterial activity against Gram-positive (Bacillus cereus, Staphylococcus aureus) and Gram-negative strains (Serratia sp., Pseudomonos sp., Escherichia coli).

New Inorganic-Organic Hybrid Polymers for Integrated Optics

1998 ◽  
Vol 519 ◽  
Author(s):  
Christof Roscher ◽  
Ralf Buestrich ◽  
Peter Dannberg ◽  
Oliver Rösch ◽  
Michael Popall
Keyword(s):  
Integrated Optics ◽  
Sol Gel ◽  
Optoelectronic Devices ◽  
Transmission Losses ◽  
Hybrid Polymers ◽  
Organic Hybrid ◽  
Catalyst Temperature ◽  
Tunable Refractive Index ◽  
Crosslinking Reactions ◽  
Gel Processing

AbstractNew fluorinated inorganic-organic hybrid polymers (ORMOCER*s) for integrated optics were synthesized via hydrolysis and condensation (sol-gel processing) of functionalized pentafluorophenylalkoxysi lanes followed by organic crosslinking reactions. Process parameters (catalyst, temperature and ratio of educts) were optimized to achieve low transmission losses at the most important wavelengths for telecommunication in the NIR range: 1310 nm and 1550 nm.The result is a photopatternable transparent ORMOCER (negative resist behavior) with excellent low losses: 0.20 dB/cm at 1310 nm and 0.30 dB/cm at 1550 nm.Besides their high transparency the fluorinated ORMOCERs show a variety of other properties enabling their use as waveguide materials within the production of optoelectronic devices and related thin film technology: good wetting and adhesion on various substrates (e.g. glass, silicon and several polymers), low processing temperatures (postbake below 160 °C), high thermal stability (decomposition > 250°C) and a tunable refractive index.

scholarly journals Chemical Composition and Antimicrobial Activity of the Essential Oil from Chaerophyllum Aureum L. (Apiaceae)

2009 ◽  
Vol 4 (1) ◽  
pp. 1934578X0900400 ◽  
Author(s):  
Branislava Lakušić ◽  
Violeta Slavkovska ◽  
Milica Pavlović ◽  
Marina Milenković ◽  
Jelena Antić Stanković ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Candida Albicans ◽  
Chemical Composition ◽  
Micrococcus Luteus ◽  
Bacterial Strains ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Aerial Parts

The essential oils of the aerial parts and fruits of Chaerophyllum aureum L., collected from two mountains in Serbia, were analyzed by GC and GC/MS. Sabinene (18.5-31.6%), p-cymene (7.9-25.4%) and limonene (1.9-10.9%) were characterized as the main constituents. The oils were tested against six bacterial strains and one strain of yeast, Candida albicans. The highest antimicrobial activity was observed against the Gram-positive bacteria Staphylococcus aureus, S. epidermidis and Micrococcus luteus, while of the Gram-negative strains, Escherichia coli was the most sensitive.

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