scholarly journals Bovine NK-lysin peptides exert potent antimicrobial activity against multidrug-resistant Salmonella outbreak isolates

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rohana P. Dassanayake ◽  
Briony M. Atkinson ◽  
Adam S. Mullis ◽  
Shollie M. Falkenberg ◽  
Eric M. Nicholson ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Antimicrobial Activity ◽  
Positive Charge ◽  
Direct Interaction ◽  
Multidrug Resistant ◽  
Bacterial Membrane ◽  
Transmission Electron ◽  
Dose Dependent ◽  
Net Positive Charge ◽  
Lps Binding

AbstractMultidrug-resistant (MDR) Salmonella is a threat to public health. Non-antibiotic therapies could serve as important countermeasures to control MDR Salmonella outbreaks. In this study, antimicrobial activity of cationic α-helical bovine NK-lysin-derived antimicrobial peptides was evaluated against MDR Salmonella outbreak isolates. NK2A and NK2B strongly inhibited MDR Salmonella growth while NK1 and NK2C showed minimum-to-no growth inhibition. Scrambled-NK2A, which is devoid of α-helicity but has the same net positive charge as NK2A, also failed to inhibit bacterial growth. Incubation of negatively charged MDR Salmonella with NK2A showed increased Zeta potential, indicating bacterial-peptide electrostatic attraction. Confocal and transmission electron microscopy studies revealed NK2A-mediated damage to MDR Salmonella membranes. LPS inhibited NK2A-mediated growth suppression in a dose-dependent response, suggesting irreversible NK2A-LPS binding. LPS-NK2A binding and bacterial membrane disruption was also confirmed via electron microscopy using gold nanoparticle-NK2A conjugates. Finally, NK2A-loaded polyanhydride nanoparticles showed sustained peptide delivery and anti-bacterial activity. Together, these findings indicate that NK2A α-helicity and positive charge are prerequisites for antimicrobial activity and that MDR Salmonella killing is mediated by direct interaction of NK2A with LPS and the inner membrane, leading to bacterial membrane permeabilization. With further optimization using nano-carriers, NK2A has the potential to become a potent anti-MDR Salmonella agent.

scholarly journals Potential Decontamination of Drinking Water Pathogens through k-Carrageenan Integrated Green Bottle Fly Bio-Synthesized Silver Nanoparticles

Molecules ◽  
2020 ◽  
Vol 25 (8) ◽  
pp. 1936 ◽  
Author(s):  
M. A. Abu-Saied ◽  
Mohamed Elnouby ◽  
Tarek Taha ◽  
Muhammad El-shafeey ◽  
Ali G. Alshehri ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Antimicrobial Activity ◽  
Silver Nanoparticles ◽  
Drinking Water ◽  
Pathogenic Bacteria ◽  
Polymeric Nanoparticles ◽  
Wide Distribution ◽  
Spectrophotometric Analysis ◽  
Transmission Electron ◽  
Green Bottle

The wide distribution of infections-related pathogenic microbes is almost related to the contamination of food and/or drinking water. The current applied treatments face some limitations. In the current study, k-carrageenan polymer was used as supporting material for the proper/unreleased silver nanoparticles that showed strong antimicrobial activity against six pathogenic bacteria and yeast. The bio-extract of the pupa of green bottle fly was used as the main agent for the synthesis of silver nanoparticles. The qualitative investigation of biologically synthesized silver nanoparticles was determined using UV-Vis spectrophotometric analysis; however, the size of nanoparticles was in range of 30–100 nm, as confirmed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and particle size analyzer. The proper integration of silver nanoparticles into the polymeric substrate was also characterized through fourier transform infrared (FT-IR), thermogravimetric analysis (TGA), SEM, and tensile strength. The antimicrobial activity of k-carrageenan/silver nanoparticles against Gram positive, Gram negative, and yeast pathogens was highly effective. These results indicate the probable exploitation of the polymeric/nanoparticles composite as an extra stage in water purification systems in homes or even at water treatment plants.

scholarly journals Multifunctional Epoxy/Nanocomposites Based on Natural Moroccan Clays with High Antimicrobial Activity: Morphological, Thermal and Mechanical Properties

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
M. Monsif ◽  
A. Zerouale ◽  
N. Idrissi Kandri ◽  
R. Bertani ◽  
A. Bartolozzi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Antimicrobial Activity ◽  
Environmental Scanning Electron Microscopy ◽  
Environmental Scanning ◽  
Clay Nanocomposites ◽  
Mechanical And Thermal Properties ◽  
Clay Dispersion ◽  
Mechanical Stirring ◽  
Antimicrobial Materials ◽  
Transmission Electron

In this study, a series of new epoxy/clay nanocomposites (ECN) has been prepared and characterized in order to investigate the properties and compare the effect of the unmodified Moroccan clay on the structure and properties of the composite materials. Five natural clays have been used to reinforce the neat epoxy resin with 1% wt and 5% wt achieving the clay dispersion only through strong milling and mechanical stirring without previous organic modifications of the clays. The quality of clay dispersion in the epoxy matrix and the morphology of nanocomposites have been studied by transmission electron microscopy (TEM), environmental scanning electron microscopy (ESEM), and X-ray diffraction (XRD). The mechanical and thermal properties have also been investigated. The antimicrobial activity of the nanocomposites has been tested against E. coli and S. aureus in order to evaluate their applicability as advanced antimicrobial materials. The results showed that the epoxy/crude clay nanocomposites exhibited a high inhibition action attending 99% against both bacteria in the case of the clay labeled A5.

scholarly journals Ultrastructural Study of Elaeis guineensis (Oil Palm) Leaf and Antimicrobial Activity of its Methanol Extract against Staphylococcus Aureus

2016 ◽  
Vol 12 (3) ◽  
pp. 419-423 ◽  
Author(s):  
Amala Rajoo ◽  
Sreenivasan Sasidharan ◽  
Subramanion L Jothy ◽  
Surash Ramanathan ◽  
Sharif M Mansor
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Staphylococcus Aureus ◽  
Transmission Electron Microscopy ◽  
Antimicrobial Activity ◽  
Methanol Extract ◽  
Elaeis Guineensis ◽  
Transmission Electron ◽  
Inhibition Concentration ◽  
Scanning Electron

Purpose: To evaluate the antimicrobial activity of the methanol extract of Elaeis guineensis leaf against Staphylococcus aureus and to determine the effect of extract treatment on the microstructure of the microbeMethods: The antimicrobial activity of the methanol leaf extract of the plant against S. aureus was examined using disc diffusion and broth dilution methods. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were carried out to determine the major alterations in the microstructure of S. aureus after treatment with the extract.Results: The extract showed a good antimicrobial activity against S. aureus with a minimum inhibition concentration (MIC) of 6.25 mg/mL and for Chloramphenicol was 30.00 ìg/mL. The main changes observed under SEM and TEM were structural disorganization of the cell membrane which occurred after 12 h and total collapse of the cell 36 h after exposure to the extract.Conclusion: We concluded that the methanolic extract of E. guineensis leaf exhibited good antimicrobial activity against S. aureus and this is supported by SEM and TEM.Keywords: Antimicrobial activity, Elaeis guineensis, Staphylococcus aureus, Scanning electron microscopy, Transmission electron microscopy

Loading AKBA on surface of silver nanoparticles to improve their sedative-hypnotic and anti-inflammatory efficacies

Nanomedicine ◽  
2019 ◽  
Vol 14 (21) ◽  
pp. 2783-2798
Author(s):  
Ajmal Khan ◽  
Ahmed Al-Harrasi ◽  
Najeeb Ur Rehman ◽  
Rizwana Sarwar ◽  
Touqeer Ahmad ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Silver Nanoparticles ◽  
Water Solubility ◽  
Boswellic Acid ◽  
Transmission Electron ◽  
Anti Inflammatory ◽  
Compound Materials ◽  
Dose Dependent ◽  
Scanning Electron

Aim: Acetyl-11-keto- β-boswellic acid (AKBA) is a potent anti-inflammatory compound limited by its low water solubility and bioavailability. To load AKBA on silver nanoparticles (AgNPs) to improve bioavailability and water solubility of the compound. Materials & methods: AKBA-AgNPs were chemically synthesized and characterized by UV–Vis spectrophotometry, Fourier transform infrared spectroscopy, scanning electron microscopy and transmission electron microscopy. AKBA and AKBA-Ag were studied for their sedative-hypnotic and anti-inflammatory efficacies. Results: Pretreatment with AKBA or AKBA-Ag caused significant dose-dependent sedative-hypnotic effects at 5 and 10 mg/kg intraperitoneal. The effects of AKBA-loaded AgNPs caused pronounced changes in mice compared with those of AKBA, and the AKBA-AgNPs demonstrated anti-inflammatory effects that were superior to those of AKBA. Conclusion: The loading of AKBA on nanoparticles improved its pharmacokinetic effects, and capacity for drug delivery.

scholarly journals Evaluation of Samarium Doped Hydroxyapatite, Ceramics for Medical Application: Antimicrobial Activity

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
C. S. Ciobanu ◽  
S. L. Iconaru ◽  
C. L. Popa ◽  
M. Motelica-Heino ◽  
D. Predoi
Keyword(s):  
Electron Microscopy ◽  
Antimicrobial Activity ◽  
Antibacterial Activity ◽  
Enterococcus Faecalis ◽  
Medical Application ◽  
Inhibitory Effect ◽  
Linear Increase ◽  
High Antibacterial Activity ◽  
Hydroxyapatite Ceramics ◽  
Transmission Electron

Samarium doped hydroxyapatite (Sm:HAp),Ca10-xSmx(PO4)6(OH)2(HAp), bionanoparticles with differentxSmhave been successfully synthesized by coprecipitation method. Detailed characterization of samarium doped hydroxyapatite nanoparticles (Sm:HAp-NPs) was carried out using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FTIR). The biocompatibility of samarium doped hydroxyapatite was assessed by cell viability. The antibacterial activity of the Sm:HAp-NPs was tested against Gram-negative bacteria (Pseudomonas aeruginosaandEscherichia coli) and Gram-positive bacteria (Enterococcus faecalisandStaphylococcus aureus). A linear increase of antimicrobial activity ofP. aeruginosahas been observed when concentrations of Sm:HAp-NPs in the samples withxSm=0.02were higher than 0.125 mg/mL. For Sm:HAp-NPs withxSm=0.05a significant increase of antibacterial activity onE. coliwas observed in the range 0.5–1 mg/mL. For low concentrations of Sm:HAp-NPs (xSm=0.05) from 0.031 to 0.125 mg/mL a high antibacterial activity onEnterococcus faecalishas been noticed. A growth of the inhibitory effect onS. aureuswas observed for all concentrations of Sm:HAp-NPs withxSm=0.02.

scholarly journals Effect of Biosynthesized ZnO Nanoparticles on Multi-Drug Resistant Pseudomonas Aeruginosa

Antibiotics ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 260 ◽  
Author(s):  
Syed Ghazanfar Ali ◽  
Mohammad Azam Ansari ◽  
Mohammad A. Alzohairy ◽  
Mohammad N. Alomary ◽  
Mohammad Jalal ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Pseudomonas Aeruginosa ◽  
Virulence Factors ◽  
Environmentally Friendly ◽  
Cost Effective ◽  
Multidrug Resistant ◽  
Zno Nps ◽  
Synthesis Of Nanoparticles ◽  
Transmission Electron ◽  
Average Size

Synthesis of nanoparticles using the plants has several advantages over other methods due to the environmentally friendly nature of plants. Besides being environmentally friendly, the synthesis of nanoparticles using plants or parts of the plants is also cost effective. The present study focuses on the biosynthesis of zinc oxide nanoparticles (ZnO NPs) using the seed extract of Butea monsoperma and their effect on to the quorum-mediated virulence factors of multidrug-resistant clinical isolates of Pseudomonas aeruginosa at sub minimum inhibitory concentration (MIC). The synthesized ZnO NPs were characterized by different techniques, such as Fourier transform infra-red spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), and transmission electron microscopy (TEM). The average size of the nanoparticles was 25 nm as analyzed by TEM. ZnO NPs at sub MIC decreased the production of virulence factors such as pyocyanin, protease and hemolysin for P. aeruginosa (p ≤ 0.05). The interaction of NPs with the P. aeruginosa cells on increasing concentration of NPs at sub MIC levels showed greater accumulation of nanoparticles inside the cells as analyzed by TEM.

Object Oriented Database and Electronic Notebook for Transmission Electron Microscopy

2003 ◽  
Vol 9 (6) ◽  
pp. 556-565 ◽  
Author(s):  
Steven J. Ludtke ◽  
Laurie Nason ◽  
Haili Tu ◽  
Liwei Peng ◽  
Wah Chiu
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Object Oriented ◽  
Direct Interaction ◽  
Large Data ◽  
Data Sets ◽  
Maximum Information ◽  
Transmission Electron ◽  
Database Structure ◽  
Object Oriented Database

As high-resolution biological transmission electron microscopy (TEM) has increased in popularity over recent years, the volume of data and number of projects underway has risen dramatically. A robust tool for effective data management is essential to efficiently process large data sets and extract maximum information from the available data. We present the Electron Microscopy Electronic Notebook (EMEN), a portable, object-oriented, web-based tool for TEM data archival and project management. EMEN has several unique features. First, the database is logically organized and annotated so multiple collaborators at different geographical locations can easily access and interpret the data without assistance. Second, the database was designed to provide flexibility to the user, so it can be used much as a lab notebook would be, while maintaining a structure suitable for data mining and direct interaction with data-processing software. Finally, as an object-oriented database, the database structure is dynamic and can be easily extended to incorporate information not defined in the original database specification.

scholarly journals Azoxymethane-induced fulminant hepatic failure in C57BL/6J mice: characterization of a new animal model

1999 ◽  
Vol 277 (2) ◽  
pp. G455-G462 ◽  
Author(s):  
Kristina A. Matkowskyj ◽  
Jorge A. Marrero ◽  
Robert E. Carroll ◽  
Alexey V. Danilkovich ◽  
Richard M. Green ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Animal Model ◽  
Fulminant Hepatic Failure ◽  
Hepatic Failure ◽  
Serum Glucose ◽  
Astrocyte Swelling ◽  
Sinusoidal Dilatation ◽  
Transmission Electron ◽  
Dose Dependent

Without transplantation, ∼50–90% of all patients with fulminant hepatic failure (FHF) die. This poor outcome is due in part to the absence of an appropriate animal model, which would allow for a greater understanding of the pathophysiology of this syndrome. Given the reports of liver injury in humans and livestock fed cycad palm nuts on the island of Guam, we hypothesized that the active ingredient azoxymethane (AOM) could cause FHF. We therefore evaluated AOM in C57BL/6J mice. Histologically, we observed microvesicular steatosis 2 h, sinusoidal dilatation 4 h, and centrilobular necrosis 20 h after AOM administration, and transmission electron microscopy showed that this agent causes mitochondrial injury. FHF was associated with all four stages of encephalopathy, as well as by a prodromal period of decreased eating and drinking lasting ∼15 h before the development of stage I encephalopathy (i.e., loss of scatter reflex). Late encephalopathy was associated with increased arterial ammonia, decreased serum glucose, and evidence of brain edema (astrocyte swelling). We show that AOM-induced FHF is highly reproducible, without evidence of lot-to-lot variability, and is dose dependent. These findings therefore suggest that AOM is an excellent agent for the study of FHF, as well as indicate that Guamanian FHF may be due to AOM found in unwashed cycad palm nuts.

scholarly journals Click-correlative light and electron microscopy (click-AT-CLEM) for imaging and tracking azido-functionalized sphingolipids in bacteria

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Simon Peters ◽  
Lena Kaiser ◽  
Julian Fink ◽  
Fabian Schumacher ◽  
Veronika Perschin ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Antimicrobial Activity ◽  
Outer Membrane ◽  
Light And Electron Microscopy ◽  
Super Resolution ◽  
Hydroxyl Group ◽  
Side Chain ◽  
Gram Negative ◽  
Array Tomography ◽  
Transmission Electron

AbstractSphingolipids, including ceramides, are a diverse group of structurally related lipids composed of a sphingoid base backbone coupled to a fatty acid side chain and modified terminal hydroxyl group. Recently, it has been shown that sphingolipids show antimicrobial activity against a broad range of pathogenic microorganisms. The antimicrobial mechanism, however, remains so far elusive. Here, we introduce ‘click-AT-CLEM’, a labeling technique for correlated light and electron microscopy (CLEM) based on the super-resolution array tomography (srAT) approach and bio-orthogonal click chemistry for imaging of azido-tagged sphingolipids to directly visualize their interaction with the model Gram-negative bacterium Neisseria meningitidis at subcellular level. We observed ultrastructural damage of bacteria and disruption of the bacterial outer membrane induced by two azido-modified sphingolipids by scanning electron microscopy and transmission electron microscopy. Click-AT-CLEM imaging and mass spectrometry clearly revealed efficient incorporation of azido-tagged sphingolipids into the outer membrane of Gram-negative bacteria as underlying cause of their antimicrobial activity.

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