Isolation and characterization of the peptidoglycans from selected Gram-positive and Gram-negative periodontal pathogens

1985 ◽  
Vol 31 (2) ◽  
pp. 154-160 ◽  
Author(s):  
M. R. Barnard ◽  
S. C. Holt
Keyword(s):  
Electron Microscopy ◽  
Diaminopimelic Acid ◽  
Muramic Acid ◽  
Periodontal Pathogens ◽  
Gram Positive ◽  
Gram Negative ◽  
Isolation And Characterization ◽  
Bacteroides Gingivalis ◽  
Scanning Electron

The peptidoglycans from several Gram-negative and Gram-positive periodontal pathogens were isolated, purified, and characterized both morphologically and chemically. In addition, the effects of the mureolytic enzymes, lysozyme, M-1 N-acetyl-muramidase, and the AM-3 endopeptidase, on the peptidoglycans were examined. These enzymes were found to be highly effective in the degradation of the purified peptidoglycans; however, a Bacteroides capillus peptidoglycan–protein complex exhibited a greater resistance to these enzymes. Morphologically, the peptidoglycans consisted of large saccular sheets which, when viewed by scanning electron microscopy, contained numerous holes and tears. Chemically, the peptidoglycans consisted of muramic acid, glucosamine, alanine, glutamic acid, and meso-diaminopimelic acid (DAP). One Bacteroides species, Bacteroides gingivalis strain W, contained glycine and LL-DAP, suggestive of an indirectly cross-linked A3γ peptidoglycan.

Al2O3 Nanopowders, a Suitable Compound for Active Control of Biofouling

2015 ◽  
Vol 32 ◽  
pp. 71-80
Author(s):  
Mohsen Mehregan ◽  
Hossein Soltaninejad ◽  
Behnaz Toluei Nia ◽  
Hadi Zare-Zardini ◽  
Masoud Zare-Shehneh ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Antibacterial Activity ◽  
Blood Cells ◽  
Gram Negative Bacteria ◽  
Bacterial Strains ◽  
X Ray Diffraction ◽  
Gram Positive ◽  
Gram Negative ◽  
X Ray

The formation of biofilm (Biofouling) in different surface is the great concern in types of fields, especially in medical and health system as well as in membrane technology. The present study deals with the synthesis and characterization of Al2O3 nanopowders with antibacterial activity which can be a potentially utilized material for biocompatible implants. Nanostructure was synthesized based on sol-gel method and then, crystallite size, and microstructural and morphological characterization of nanostructure were determined by X-ray diffraction, electron-microscopic techniques - scanning electron microscopy (SEM) and transmission electron microscopy (TEM). According to X-ray diffraction, the value of particle size for Al2O3 nanopowders is 20.85 nm. In the following, the antibacterial activity of Al2O3 nanoparticles was assessed on three gram positive and three gram negative bacteria by radial diffusion assay and measurement of minimum inhibitory concentration (MIC). The toxicity of Al2O3 nanopowders on blood cells was also assessed. The results showed that this nanostructure has potent antibacterial activity against gram positive and gram negative bacteria. The synthesized Al2O3 nanopowders showed the antimicrobial activity against antibiotic resistant bacterium, Staphylococcus aureus. Significant antibacterial activity of this nanostructure was seen to have a greatest effect on Bacillus cereus with the MIC value of 9.2 μg/ml; while, among bacterial strains, Salmonellatyphimurium was investigated to be the most resistant one with the MIC of 35.6 μg/ml. Al2O3 nanopowders showed no toxicity on blood cells. according to acquired data in this study, Al2O3 nanopowders may be a good material for inhibition of biofilm formation.

Isolation and characterization of Gram-negative and Gram-positive bacteria capable of producing piceatannol from resveratrol

2019 ◽  
Vol 103 (14) ◽  
pp. 5811-5820 ◽  
Author(s):  
Toshiki Furuya ◽  
Naoto Imaki ◽  
Kosuke Shigei ◽  
Masahiko Sai ◽  
Kuniki Kino
Keyword(s):  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Isolation And Characterization

scholarly journals Biocatalytic and Biological Activities of Cassia Occidentalis Mediated Silver Nanoparticles

2022 ◽  
Vol 19 (1) ◽  
pp. 1712
Author(s):  
Shashika Singh ◽  
Viresh Mohanlall
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Silver Nanoparticles ◽  
Leaf Extracts ◽  
Gram Positive ◽  
Cassia Occidentalis ◽  
Gram Negative ◽  
Transmission Electron ◽  
Scanning Electron

Silver nanoparticles (AgNPs) were synthesized using the leaf extracts from Cassia occidentalis. The reactions were marked by a distinct colour change and the formation of AgNPs was monitored by measuring the UV-Vis spectra. The morphology and crystalline phase of the metal nanoparticles were determined using Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray analysis (EDX) and Fourier-Transform-Infrared Spectroscopy (FTIR). The biocatalytic activity of the AgNPs against nitrifying compounds was determined using 4-nitrophenol and 4-nitroalanine. The biological screening involved analyzing the AgNPs effectiveness against gram-negative and gram-positive bacteria (Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa, Bacillus cereus and Enterococcus faecalis). The AgNPs displayed minimal inhibition at low concentrations ranging from 25 to 50 μg/mL. The toxicity of the AgNPs was tested using the brine shrimp assay and was observed as non-toxic with a nearly zero mortality rate. The AgNPs exhibited an antioxidant potential of 70.90 % inhibition at 1000 µg/mL. C. occidentalis is noted as a potential bioresource for synthesizing AgNPs with applications as antibacterial, antioxidant and biocatalytic agents. HIGHLIGHTS The addition of Ag nanoparticles to C. occidentalis plant extracts resulted in the formation of AgNPs-C. occidentalis complexes The AgNPs-C. occidentalis complexes were characterized using Transmission Electron Microscopy, Scanning Electron Microscopy with EDX, UV-Vis spectrophotometry and IR spectroscopy These AgNPs-C. occidentalis complexes were very stable and showed antibacterial activity against a range of tested gram-positive and gram-negative bacteria at low doses, thus proving to be good antimicrobial agents The AgNPs-C. occidentalis complexes showed higher scavenging activity than leaf extracts of C. occidentalis. The AgNPs have increased catalytic ability for the reduction of 4-nitrophenol and 4-nitroalanine after a 30 min time interval GRAPHICAL ABSTRACT

scholarly journals Isolation and characterization of fungi from deteriorated old manuscripts from Banyumas, collection of Library of Universitas Indonesia

2021 ◽  
Vol 948 (1) ◽  
pp. 012031
Author(s):  
W Lintang ◽  
T Susetyo-Salim ◽  
A Oetari ◽  
W Sjamsuridzal
Keyword(s):  
Electron Microscopy ◽  
Fungal Spores ◽  
Carbon Sources ◽  
Morphological Characteristics ◽  
Fungal Growth ◽  
Dry Weight ◽  
Isolation And Characterization ◽  
Fungal Isolates ◽  
Scanning Electron

Abstract Fungi are the main cause of old manuscript deterioration since manuscripts provide carbon source and nutrient for fungal growth. Isolation of fungi from deteriorated old manuscripts from Banyumas was carried out and their morphology, xerophilic, and cellulolytic nature were investigated. Two deteriorated old dluwang manuscripts showed fungal spores, brown spots, and discoloured paper. Based on morphological characteristics, 31 fungal isolates belonged to five genera (Aspergillus Micheli, Cladosporium Link, Curvularia Boedijn, Penicillium Link, Ulocladium Preuss). These genera have been reported from deteriorated old manuscripts from several historical places in Indonesia. Xerophilic character was shown by 90% (28 isolates) as determined by growth in DG18 medium, which indicated the ability to grow in dry substrates such as old manuscripts. Cellulolytic character was shown by 93.5% (29 isolates) as determined by growth in dluwang paper and merang paper, which indicated that the papers were used as carbon sources and substrates. After 30 days-incubation, the dry weight loss of merang paper was 0.28-51.2%. Result from Scanning Electron Microscopy showed that the deterioration of merang paper were caused by the isolates as shown by the presence of fungal structures. These results showed that the fungal isolates were able to deteriorate old manuscripts from Banyumas, Indonesia.

Synthesizing selenium- and silver-substituted hydroxyapatite-based bone grafts and their effects on antibacterial efficiency and cell viability

2018 ◽  
Vol 63 (3) ◽  
pp. 291-300
Author(s):  
Bunyamin Aksakal ◽  
Mehtap Demirel ◽  
Zeynep A. Sinirlioglu
Keyword(s):  
Electron Microscopy ◽  
Cell Viability ◽  
Sol Gel ◽  
Control Group ◽  
Gram Positive ◽  
Gram Negative ◽  
X Ray ◽  
E Coli ◽  
Scanning Electron

Abstract Hydroxyapatite (HA)-based biografts with selenium (Se) and silver (Ag) substitutions were synthesized using the sol-gel method. The synthesized HA-based biografts at various Se and Ag quantity ratios (wt%) were characterized via Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy dispersive X-Ray spectroscopy (EDX). Escherichia coli (JM103) and Gram-positive Staphylococcus aureus (ATCC29293) bacteria were used for the cell viability tests by performing the MTT assay. During antibacterial tests, it was determined that the synthesized biografts showed significant antimicrobial activity on E. coli and S. aureus; however, some materials were effective on Gram-negative E. coli, but had no effect on Gram-positive S. aureus. In vitro cell viability tests revealed that some of the synthesized biografts such as H30Ag10Se15 and H40Ag20Se10 provided the highest cell viability rates compared to those in the control group.

Characterization of CMOS Structures (0.6 µm process) Submitted to HBM and COM ESD Stress Tests

1997 ◽  
Author(s):  
G. Meneghesso ◽  
E. Zanoni ◽  
P. Colombo ◽  
M. Brambilla ◽  
R. Annunziata ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Electrostatic Discharge ◽  
Stress Test ◽  
Complete Characterization ◽  
Stress Tests ◽  
Test Procedures ◽  
Emission Microscopy ◽  
Fast Rise ◽  
Scanning Electron

Abstract In this work, we present new results concerning electrostatic discharge (ESD) robustness of 0.6 μm CMOS structures. Devices have been tested according to both HBM and socketed CDM (sCDM) ESD test procedures. Test structures have been submitted to a complete characterization consisting in: 1) measurement of the tum-on time of the protection structures submitted to pulses with very fast rise times; 2) ESD stress test with the HBM and sCDM models; 3) failure analysis based on emission microscopy (EMMI) and Scanning Electron Microscopy (SEM).

Isolasi Dan Karakterisasi Bentonit Alam Menjadi Nanopartikel Monmorillonit

2018 ◽  
Vol 3 (1) ◽  
pp. 12 ◽  
Author(s):  
Zaimahwati Zaimahwati ◽  
Yuniati Yuniati ◽  
Ramzi Jalal ◽  
Syahman Zhafiri ◽  
Yuli Yetri
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Particle Size ◽  
Surface Morphology ◽  
Average Diameter ◽  
Particle Size Analyzer ◽  
Ft Ir ◽  
Scanning Electron ◽  
Sedimentation Processes

<p>Pada penelitian ini telah dilakukan isolasi dan karakterisasi bentonit alam menjadi nanopartikel montmorillonit. Bentonit alam yang digunakan diambil dari desa Blangdalam, Kecamatan Nisam Kabupaten Aceh Utara.  Proses isolasi meliputi proses pelarutan dengan aquades, ultrasonic dan proses sedimentasi. Untuk mengetahui karakterisasi montmorillonit dilakukan uji FT-IR, X-RD dan uji morfologi permukaan dengan Scanning Electron Microscopy (SEM). Partikel size analyzer untuk menganalisis dan menentukan ukuran nanopartikel dari isolasi bentonit alam. Dari hasil penelitian didapat ukuran nanopartikel montmorillonit hasil isolasi dari bentonit alam diperoleh berdiameter rata-rata 82,15 nm.</p><p><em>In this research we have isolated and characterized natural bentonite into montmorillonite nanoparticles. Natural bentonite used was taken from Blangdalam village, Nisam sub-district, North Aceh district. The isolation process includes dissolving process with aquades, ultrasonic and sedimentation processes.  The characterization of montmorillonite, FT-IR, X-RD and surface morphology test by Scanning Electron Microscopy (SEM). Particle size analyzer to analyze and determine the size of nanoparticles from natural bentonite insulation. From the research results obtained the size of montmorillonite nanoparticles isolated from natural bentonite obtained an average diameter of 82.15 nm.</em></p>

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