Hydrogel supported positively charged ultrathin polyamide layer with antimicrobial properties via Ag modification

AbstractA polyelectrolyte multilayer film with antimicrobial properties was prepared by the layer-by-layer technique on porous cellulose membranes by the alternate adsorption of hydrophobically modified polyvinylamine (PVAm) and polyacrylic acid. The approach included the introduction of negative charges onto cellulose membranes by NaBr and TEMPO-catalysed oxidation which created anchoring sites for the positively charged PVAm. The antibacterial activity of the cellulose membranes were tested with the Gram-negative bacteriumEscherichia colias organism. A significant decrease in bacterial growth was observed with increasing number of polymeric bilayers (between three and six layers of cationic polymer) on the cellulose membranes. The antimicrobial property was ascribed to the modified PVAm.

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Photocatalytic and Antimicrobial Properties of Ag2O/TiO2 Heterojunction

ChemEngineering ◽

10.3390/chemengineering3010003 ◽

2019 ◽

Vol 3 (1) ◽

pp. 3 ◽

Cited By ~ 10

Author(s):

Maya Endo-Kimura ◽

Marcin Janczarek ◽

Zuzanna Bielan ◽

Dong Zhang ◽

Kunlei Wang ◽

...

Keyword(s):

Diffuse Reflectance Spectroscopy ◽

Antimicrobial Properties ◽

Simple Method ◽

Oxidative Decomposition ◽

X Ray ◽

Transmission Electron ◽

Scanning Transmission ◽

Negative Surface ◽

Almost All ◽

Positively Charged

Ag2O/TiO2 heterojunctions were prepared by a simple method, i.e., the grinding of argentous oxide with six different titania photocatalysts. The physicochemical properties of the obtained photocatalysts were characterized by diffuse-reflectance spectroscopy (DRS), X-ray powder diffraction (XRD) and scanning transmission electron microscopy (STEM) with an energy dispersive X-ray spectroscopy (EDS). The photocatalytic activity was investigated for the oxidative decomposition of acetic acid and methanol dehydrogenation under UV/vis irradiation and for the oxidative decomposition of phenol and 2-propanol under vis irradiation. Antimicrobial properties were tested for bacteria (Escherichia coli) and fungi (Candida albicans and Penicillium chrysogenum) under UV and vis irradiation and in the dark. Enhanced activity was observed under UV/vis (with synergism for fine anatase-containing samples) and vis irradiation for almost all samples. This suggests a hindered recombination of charge carriers by p-n heterojunction or Z-scheme mechanisms under UV irradiation and photo-excited electron transfer from Ag2O to TiO2 under vis irradiation. Improved antimicrobial properties were achieved, especially under vis irradiation, probably due to electrostatic attractions between the negative surface of microorganisms and the positively charged Ag2O.

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Colloidal Stability of Positively Charged Dispersions of Styrene and Acrylic Copolymers in the Presence of TiO2 and CaCO3

Colloids and Interfaces ◽

10.3390/colloids3010020 ◽

2019 ◽

Vol 3 (1) ◽

pp. 20 ◽

Cited By ~ 1

Author(s):

Kamil Wojciechowski ◽

Małgorzata Gutarowicz ◽

Kamil Janke ◽

Ilona Jurek ◽

Marcin Kaczorowski ◽

...

Keyword(s):

Cetyltrimethylammonium Bromide ◽

Colloidal Stability ◽

Antimicrobial Properties ◽

Ethyl Acrylate ◽

Ζ Potential ◽

Bacterial Diseases ◽

Latex Dispersions ◽

Acrylic Copolymers ◽

Alternative Approaches ◽

Positively Charged

Increasing antibiotic resistance of several pathogenic microorganisms calls for alternative approaches to prevent spreading of bacterial diseases. We propose to employ for this purpose coatings obtained from positively charged latex dispersions. In this contribution we characterize aqueous mixed dispersions containing TiO2 or CaCO3 and methyl methacrylate-ethyl acrylate or styrene-ethyl acrylate copolymers synthesized using a cationic surfactant, cetyltrimethylammonium bromide as an emulsifier. Particle size, electrokinetic (ζ) potential of the mixed dispersions and the resulting thin films, as well as antimicrobial properties of the latter are described. The TiO2 and CaCO3 dispersions were stabilised with polyethyleneimine (PEI) and optimum pH for the mixed dispersions were chosen on the basis of ζ-potential measurements. For TiO2, the maximum ζ = +35 mV was found at pH 7.5, and for CaCO3, pH was set at 8.2 (ζ = +38 mV), to prevent its dissolution. In most 1:1 mixtures of TiO2 or CaCO3 with the cetyltrimethylammonium bromide (CTAB)-stabilised latex dispersions, two distinct particles populations were observed, corresponding to the bare latex and bare TiO2 or CaCO3 fractions. Films made of the mixed dispersions remained positively charged and showed antimicrobial activity similar or reduced with respect to the bare polymer films.

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Size Attenuated Copper Doped Zirconia Nanoparticles Enhances in Vitro Antimicrobial Properties

10.21203/rs.3.rs-807437/v1 ◽

2021 ◽

Author(s):

Nishakavya S ◽

Agnishwar Girigoswami ◽

Deepa R ◽

Divya A ◽

Ajith S ◽

...

Keyword(s):

Mammalian Cells ◽

Biomedical Applications ◽

Antimicrobial Properties ◽

Gram Positive ◽

Antimicrobial Drugs ◽

Xtt Assay ◽

Gram Positive Bacteria ◽

Positively Charged ◽

Zirconia Nanoparticles

Abstract Biofilm formation hinders the activity of antimicrobial drugs at the site of infections and any agent that can act on both Gram- positive and Gram- bacteria by inhibiting the bacterial growth and rupture the biofilm is needed for the management of infection. In the present study, we have synthesized ZrO2 NPs and copper doped zirconia nanoparticles (Cu-ZrO2 NPs) and characterized them using dynamic light scattering, X-ray diffractometry and scanning electron microscopy (SEM). The size of the Cu-ZrO2 NPs drastically reduced compared to ZrO2 NPs and the antimicrobial activity was studied against Gram- positive bacteria (Lactobacillus sp.) and Gram- negative bacteria (Pseudomonas aeruginosa), respectively. The synthesized Cu-ZrO2 NPs showed superior inhibitory action against Lactobacillus sp. compared to ZrO2 NPs, due to the negatively charged cell wall of Lactobacillus sp. which could attract readily the positively charged Cu-ZrO2 NPs, thereby inhibiting its activity. The biocompatibility was tested using XTT assay in FL cells and the results demonstrated that Cu-ZrO2 NPs were non- toxic to mammalian cells. Hence, it could be proposed that the synthesized Cu-ZrO2 NPs possess possible biomedical applications and can be used as antibacterial agents without causing toxicity in mammalian cells.

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Protamine-DNA interaction

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100081863 ◽

1978 ◽

Vol 36 (2) ◽

pp. 200-201

Author(s):

D.P. Bazett-Jones ◽

F.P. Ottensmeyer

Keyword(s):

Small Volume ◽

Double Helix ◽

Dna Interaction ◽

Dark Field ◽

Sperm Head ◽

Nuclear Proteins ◽

Field Electron Microscopy ◽

Dark Field Electron ◽

Dna Double Helix ◽

Positively Charged

Dark field electron microscopy has been used for the study of the structure of individual macromolecules with a resolution to at least the 5Å level. The use of this technique has been extended to the investigation of structure of interacting molecules, particularly the interaction between DNA and fish protamine, a class of basic nuclear proteins of molecular weight 4,000 daltons.Protamine, which is synthesized during spermatogenesis, binds to chromatin, displaces the somatic histones and wraps up the DNA to fit into the small volume of the sperm head. It has been proposed that protamine, existing as an extended polypeptide, winds around the minor groove of the DNA double helix, with protamine's positively-charged arginines lining up with the negatively-charged phosphates of DNA. However, viewing protamine as an extended protein is inconsistent with the results obtained in our laboratory.

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Structure and Interaction of Protamine by Dark Field Electron Microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100090786 ◽

1976 ◽

Vol 34 ◽

pp. 160-161

Author(s):

D.P. Bazett-Jones ◽

F.P. Ottensmeyer

Keyword(s):

Electron Microscopy ◽

Dark Field ◽

Amino Acid Sequences ◽

Dimensional Structure ◽

3 Dimensional ◽

Field Electron ◽

Proposed Model ◽

Field Electron Microscopy ◽

Dark Field Electron ◽

Positively Charged

It has been shown for some time that it is possible to obtain images of small unstained proteins, with a resolution of approximately 5Å using dark field electron microscopy (1,2). Applying this technique, we have observed a uniformity in size and shape of the 2-dimensional images of pure specimens of fish protamines (salmon, herring (clupeine, Y-l) and rainbow trout (Salmo irideus)). On the basis of these images, a model for the 3-dimensional structure of the fish protamines has been proposed (2).The known amino acid sequences of fish protamines show stretches of positively charged arginines, separated by regions of neutral amino acids (3). The proposed model for protamine structure (2) consists of an irregular, right-handed helix with the segments of adjacent arginines forming the loops of the coil.

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Enhanced type I photoreaction of indocyanine green via electrostatic-force-driven aggregation

Nanoscale ◽

10.1039/d0nr01208d ◽

2020 ◽

Vol 12 (17) ◽

pp. 9517-9523 ◽

Cited By ~ 3

Author(s):

Huizhen Fan ◽

Yu Fan ◽

Wenna Du ◽

Rui Cai ◽

Xinshuang Gao ◽

...

Keyword(s):

Mesoporous Silica ◽

Indocyanine Green ◽

Electrostatic Force ◽

Type I ◽

Positively Charged

ICG forms aggregates in positively charged mesoporous silica, which show an enhanced type I photoreaction pathway.

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Influence of nascent polypeptide positive charges on translation dynamics

Biochemical Journal ◽

10.1042/bcj20200303 ◽

2020 ◽

Vol 477 (15) ◽

pp. 2921-2934

Author(s):

Rodrigo D. Requião ◽

Géssica C. Barros ◽

Tatiana Domitrovic ◽

Fernando L. Palhano

Keyword(s):

Mrna Decay ◽

Translation Termination ◽

Published Data ◽

Translation Efficiency ◽

Amino Acid Residues ◽

High Concentration ◽

Strong Argument ◽

Translation Arrest ◽

Exit Tunnel ◽

Positively Charged

Protein segments with a high concentration of positively charged amino acid residues are often used in reporter constructs designed to activate ribosomal mRNA/protein decay pathways, such as those involving nonstop mRNA decay (NSD), no-go mRNA decay (NGD) and the ribosome quality control (RQC) complex. It has been proposed that the electrostatic interaction of the positively charged nascent peptide with the negatively charged ribosomal exit tunnel leads to translation arrest. When stalled long enough, the translation process is terminated with the degradation of the transcript and an incomplete protein. Although early experiments made a strong argument for this mechanism, other features associated with positively charged reporters, such as codon bias and mRNA and protein structure, have emerged as potent inducers of ribosome stalling. We carefully reviewed the published data on the protein and mRNA expression of artificial constructs with diverse compositions as assessed in different organisms. We concluded that, although polybasic sequences generally lead to lower translation efficiency, it appears that an aggravating factor, such as a nonoptimal codon composition, is necessary to cause translation termination events.

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Characteristics of the Interaction between Thrombin Exosite1 and the Sequence 269-297 of Platelet Glycoprotein Ibα

Thrombosis and Haemostasis ◽

10.1055/s-0037-1615193 ◽

1998 ◽

Vol 80 (08) ◽

pp. 310-315 ◽

Cited By ~ 8

Author(s):

Marie-Christine Bouton ◽

Christophe Thurieau ◽

Marie-Claude Guillin ◽

Martine Jandrot-Perrus

Keyword(s):

Platelet Activation ◽

Electrostatic Interactions ◽

Platelet Glycoprotein ◽

Thrombin Receptor ◽

Central Position ◽

Amidolytic Activity ◽

N Terminus ◽

Hydrolysis Of ◽

Chemical Cross Linking ◽

Positively Charged

SummaryThe interaction between GPIb and thrombin promotes platelet activation elicited via the hydrolysis of the thrombin receptor and involves structures located on the segment 238-290 within the N-terminal domain of GPIbα and the positively charged exosite 1 on thrombin. We have investigated the ability of peptides derived from the 269-287 sequence of GPIbα to interact with thrombin. Three peptides were synthesized, including Ibα 269-287 and two scrambled peptides R1 and R2 which are comparable to Ibα 269-287 with regards to their content and distribution of anionic residues. However, R2 differs from both Ibα 269-287 and R1 by the shifting of one proline from a central position to the N-terminus. By chemical cross-linking, we observed the formation of a complex between 125I-Ibα 269-287 and α-thrombin that was inhibited by hirudin, the C-terminal peptide of hirudin, sodium pyrophosphate but not by heparin. The complex did not form when γ-thrombin was substituted for α-thrombin. Ibα 269-287 produced only slight changes in thrombin amidolytic activity and inhibited thrombin binding to fibrin. R1 and R2 also formed complexes with α-thrombin, modified slightly its catalytic activity and inhibited its binding to fibrin. Peptides Ibα 269-287 and R1 inhibited platelet aggregation and secretion induced by low thrombin concentrations whereas R2 was without effect. Our results indicate that Ibα 269-287 interacts with thrombin exosite 1 via mainly electrostatic interactions, which explains why the scrambled peptides also interact with exosite 1. Nevertheless, the lack of effect of R2 on thrombin-induced platelet activation suggests that proline 280 is important for thrombin interaction with GPIb.

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Antimicrobial properties of tannin extracts as animal feed

10.1055/s-0039-3399960 ◽

2019 ◽

Author(s):

S Štumpf ◽

G Hostnik ◽

M Leitgeb ◽

M Primožič ◽

U Bren

Keyword(s):

Animal Feed ◽

Antimicrobial Properties

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