scholarly journals Conformational Changes in Wheat Gluten After using Ag-nanoparticles

2014 ◽  
Vol 28 (3) ◽  
pp. 311-317 ◽  
Author(s):  
Agnieszka Nawrocka
Keyword(s):  
Aqueous Solution ◽  
Silver Nanoparticles ◽  
Secondary Structure ◽  
Conformational Changes ◽  
Fungal Infections ◽  
Wheat Gluten ◽  
Control Sample ◽  
Antimicrobial Properties ◽  
Protective Layer ◽  
Trisodium Citrate

Abstract Silver nanoparticles have antimicrobial properties since they can be regarded as an efficient protector against pathogenic microorganisms. Fourier transform infrared spectroscopy was used to examine conformational changes in the secondary structure of wheat gluten washed out from grain treated with an aqueous solution of silver nanoparticles stabilized by tri-sodium citrate. Silver nanoparticles were used as a protective layer on the grain surface against bacterial and fungal infections (antimicrobial agent). Analysis of the amide I band revealed significant changes in the secondary structure after using silver nanoparticles. An increase in the β-sheet content (from 36.2 to 39.2%) was observed at the expense of the α-helix and β-turn content. To find factors causing these changes, the wheat grains were treated by an aqueous solution of trisodium citrate and water. The results obtained indicate that the changes in the gluten structure were connected mainly with the trisodium citrate action due to presence of a small number of free molecules of the stabilizer in the solution of silver nanoparticles. Additionally, the conformational changes in gluten pointed out that gluten flexibility increased (decrease in the αH/βS ratio from 1.40 for the control sample to 1.26 for the silver nanoparticle-treated samples) as well as the solubility of gluten decreased (decrease in the β-turn content from 13.1 to 11.4%).

Effect of High Pressure Microfluidization on Secondary Structure of Wheat Gluten in Different Solvents

2013 ◽  
Vol 781-784 ◽  
pp. 770-773
Author(s):  
Zhao Xi Fang ◽  
Nai Jun Yan ◽  
Guo Qin Liu
Keyword(s):  
High Pressure ◽  
Secondary Structure ◽  
Acid Treatment ◽  
Wheat Gluten ◽  
Control Sample ◽  
Random Coil ◽  
Comprehensive Treatment ◽  
Gluten Protein ◽  
Α Helix ◽  
Β Sheet

Far-UV circular dichroism (CD) spectroscopy was used to study the conformation of wheat gluten protein treatmented by dynamic high pressure microfluidization (DHPM), acid treatment and its comprehensive treatment in two solvents. The results showed, the secondary structure of control sample are mainly consist of α-helix and random-coil in phosphate-buffered saline (PBS) and phosphate buffered solution with SDS(SDS), the secondary structure of control sample are mainly consist of β-Sheet and random-coil. The CD data also showed that SDS interacts with the gluten protein and modifies the protein conformation, which switched the conformation from α-helix and β-Turn to β-sheet and random-coil. However, the CD analysis also indicated that some of the ordered structures of α-helix, β-Turn and β-sheet were destroyed and converted random-coil coped with acid in two solvents, in other words, the acid treatment can directed change the secondary structure. Furthermore, the effect of comprehensive treatment (DHPM plus acid) is not equal to the simple sum of the individual treatment effect.

scholarly journals Influence of silver nanoparticles on food components in wheat

2013 ◽  
Vol 27 (1) ◽  
pp. 49-55 ◽  
Author(s):  
A. Nawrocka ◽  
J. Cieśla
Keyword(s):  
Silver Nanoparticles ◽  
Grain Quality ◽  
Sodium Citrate ◽  
Fungal Infections ◽  
Antimicrobial Properties ◽  
Protein Secondary Structure ◽  
Wheat Quality ◽  
Falling Number ◽  
Food Components

Abstract During storage, grain might be affected by bacterial and fungal infections. Pathogens diminish the grain quality through contamination with excrements and second metabolites. It is very important to prevent grain from infections. Due to their antimicrobial properties, silver nanoparticles can play the role of an effective protector. The influence of nanoparticles on wheat quality was studied. The gluten parameters and falling number did not change after covering the grain with silver nanoparticles stabilized by sodium citrate. Changes in the structure of starch and gluten were investigated using Fourier-transform infrared spectroscopy. Infrared spectra of the whole meal and starch have shown a slight shift (from 1 000 to 995cm-1) of the band connected with the C-O-H bending. This displacement is probably related to the changes in sample moisture. Significant differences, corresponding to changes in the protein secondary structure, have appeared in the gluten spectra after covering.A decrease of absorbance in the amide and CH and OH regions has been observed regardless of the covering time.

Synthesis and Characterization of Silver Nanoplates by a Seed-mediated Method

2019 ◽  
Vol 29 (3) ◽  
Author(s):  
Mai Ngọc Tuan Anh
Keyword(s):  
Hydrogen Peroxide ◽  
Silver Nanoparticles ◽  
Ascorbic Acid ◽  
Silver Nitrate ◽  
Sodium Borohydride ◽  
Trisodium Citrate ◽  
Synthesis And Characterization ◽  
Silver Nanoplates ◽  
Seed Mediated

Silver nanoplates (SNPs) having different size were synthesized by a seed-mediated method. The seeds -silver nanoparticles with 4 – 6 nm diameters were synthesized first by reducing silver nitrate with sodium borohydride in the present of Trisodium Citrate and Hydrogen peroxide. Then these seeds were developed by continue reducing Ag\(^+\) ions with various amount of L-Ascorbic acid to form SNPs. Our analysis showed that the concentratrion of L-Ascorbic acid, a secondary reducing agent, played an important role to form SNPs. In addition, the size and in-plane dipole plasmon resonance wavelenght of silver nanoplates were increased when the concentration of added silver nitrate increased. The characterization of SNPs were studied by UV-Vis, FE-SEM, EDS and TEM methods.

scholarly journals Silver Nanoparticles Induce Neutrophil Extracellular Traps Via Activation of PAD and Neutrophil Elastase

Biomolecules ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 317
Author(s):  
HanGoo Kang ◽  
Jinwon Seo ◽  
Eun-Jeong Yang ◽  
In-Hong Choi
Keyword(s):  
Silver Nanoparticles ◽  
Neutrophil Elastase ◽  
Mammalian Cells ◽  
Antimicrobial Properties ◽  
Neutrophil Extracellular Traps ◽  
Arginine Deiminase ◽  
Human Neutrophils ◽  
Extracellular Traps ◽  
Peptidyl Arginine Deiminase ◽  
Key Factor

Silver nanoparticles (AgNPs) are widely used in various fields because of their antimicrobial properties. However, many studies have reported that AgNPs can be harmful to both microorganisms and humans. Reactive oxygen species (ROS) are a key factor of cytotoxicity of AgNPs in mammalian cells and an important factor in the immune reaction of neutrophils. The immune reactions of neutrophils include the expulsion of webs of DNA surrounded by histones and granular proteins. These webs of DNA are termed neutrophil extracellular traps (NETs). NETs allow neutrophils to catch and destroy pathogens in extracellular spaces. In this study, we investigated how AgNPs stimulate neutrophils, specifically focusing on NETs. Freshly isolated human neutrophils were treated with 5 or 100 nm AgNPs. The 5 nm AgNPs induced NET formation, but the 100 nm AgNPs did not. Subsequently, we investigated the mechanism of AgNP-induced NETs using known inhibitors related to NET formation. AgNP-induced NETs were dependent on ROS, peptidyl arginine deiminase, and neutrophil elastase. The result in this study indicates that treatment of 5 nm AgNPs induce NET formation through histone citrullination by peptidyl arginine deiminase and histone cleavage by neutrophil elastase.

scholarly journals Tribological Performance Investigation of a Commercial Engine Oil Incorporating Reduced Graphene Oxide as Additive

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 386
Author(s):  
Hakan Kaleli ◽  
Selman Demirtaş ◽  
Veli Uysal ◽  
Ioannis Karnis ◽  
Minas M. Stylianakis ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Tribological Behavior ◽  
Control Sample ◽  
Protective Layer ◽  
Steel Ball ◽  
Carbon Accumulation ◽  
Engine Oil ◽  
Wear Scar Diameter ◽  
Reduced Graphene

We investigated the tribological behavior of commercialized, fully synthetic engine oil upon the incorporation of reduced graphene oxide in seven different concentrations between 0.01 and 0.2 wt %. Stability of the prepared samples was assessed by turbidimetry and dynamic light scattering measurements, and their tribological properties through a reciprocating tribometer, using a steel ball on special cut steel blocks. The addition of 0.02 wt % of reduced graphene oxide led to an improvement of the tribological behavior compared to the pristine engine oil, by significantly lowering the friction coefficient by 5% in the boundary lubrication regime. Both the surfaces and the reduced graphene oxide additive were thoroughly characterized by microscopic and optical spectroscopy techniques. We also verified that a protective layer was formed between the worn surfaces, due to the presence of reduced graphene oxide. Carbon accumulation and various additive elements such as Ca, Zn, S and P were detected on the rubbing surfaces of both the ball and the block through energy-dispersive X-ray spectroscopy. Finally, it was shown that the wear scar diameter on the surface of the steel ball was lower by 3%, upon testing the engine oil sample containing reduced graphene oxide at concentration 0.02 wt %, compared to the control sample.

Antimicrobial properties of silver nanoparticles prepared by Acacia etbaica (Schweinf.) valve extract

2021 ◽  
pp. 130233
Author(s):  
A. Kalam ◽  
A.G. Al-Sehemi ◽  
S. Alrumman ◽  
M.A. Assiri ◽  
A.M. Alfaify ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Antimicrobial Properties

Preparation of Triangular Silver Nanoparticles Using Polyvinyl Pyrrolidone with Different Concentration

2013 ◽  
Vol 873 ◽  
pp. 206-210
Author(s):  
Kai Li ◽  
Rao Fu ◽  
Qing Ran Gao ◽  
Ai Wei Tang ◽  
Ying Feng Wang
Keyword(s):  
Electron Microscopy ◽  
Aqueous Solution ◽  
Silver Nanoparticles ◽  
Driving Force ◽  
Ostwald Ripening ◽  
Polyvinyl Pyrrolidone ◽  
Protective Agent ◽  
Ag Nps ◽  
Transmission Electron ◽  
Uv Visible

This paper continues our previous work on preparation of triangular silver nanoparticles. The method proceeds with reaction of silver nitrate with hydrazine hydrate in the presence of polyvinyl pyrrolidone in aqueous solution. Effects of the concentration of PVP on the morphologies of Ag NPs were systematically investigated. The obtained Ag NPs were characterized by transmission electron microscopy and UV-visible spectrophotometer. The results showed that, triangular Ag NPs with edge lengths in the range of 50-200 nm were obtained using PVP as protective agent with lower concentration. As the concentration of PVP increased, spherical Ag NPs with their sizes about 6.2 nm were prepared and triangular Ag NPs were not obtained. The formation mechanism of triangular Ag NPs has been studied. Ostwald ripening is the driving force on the conversion of spherical Ag NPs to triangular Ag NPs in the presence of PVP.

Synthesis silver nanoparticles using trisodium citrate and development in analysis method

2021 ◽  
Author(s):  
Moh. Syaiful Arif ◽  
Rusda Ulfiya ◽  
Erwin ◽  
Aman Sentosa Panggabean
Keyword(s):  
Silver Nanoparticles ◽  
Trisodium Citrate ◽  
Analysis Method

PHYTO-MEDIATED SYNTHESIS OF SILVER NANOPARTICLES USING AQUEOUS EXTRACT OF „BUGLOSSOIDES PURPUROCAERULEA“ (BORAGINACEAE) AND THEIR BIOACTIVITY

2021 ◽  
Author(s):  
Jelena S. Katanić Stanković ◽  
◽  
Nikola Srećković ◽  
Vladimir Mihailović
Keyword(s):  
Silver Nanoparticles ◽  
Aqueous Extract ◽  
Radical Scavenging ◽  
Antimicrobial Properties ◽  
Bacterial Strains ◽  
Penicillium Species ◽  
Microdilution Method ◽  
Biological Potential ◽  
Vis Spectroscopy

In this study, silver nanoparticles (AgNPs) have been synthesized using the aqueous extract of the aerial parts of B. purpurocaerulea, collected in Serbia. B. purpurocaerulea silver nanoparticles (Bp– AgNPs) synthesis was confirmed using UV-Vis spectroscopy and Fourier Transform Infrared Spectroscopy (FTIR). The biological potential of synthesized Bp-AgNPs was evaluated in vitro using ABTS assay for determining free radical scavenging potential and microdilution method for analysis of antimicrobial properties. Bp-AgNPs showed high antioxidant activity similar to Bp-extract, comparable to BHT. The synthesized nanoparticles exerted remarkable antibacterial effects, with minimal inhibitory concentration (MIC) values below 20 µg/mL. In the case of some bacterial strains, the results of Bp– AgNPs were comparable or similar to standard antibiotic erythromycin. The antifungal activity of Bp– AgNPs was moderate for most of the used strains. Nevertheless, several fungi were resistant to the NPs action, while two tested Penicillium species were extremely sensitive on Bp-AgNPs with MIC lower than 40 µg/mL. The antimicrobial properties of Bp-AgNPs can be useful for the development of new NPs-containing products.

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