Preparation of multilayer polyelectrolyte ceramic membrane for water disinfection

Abstract A multilayer polyelectrolyte ceramic membrane using LbL was assembled to test the performance of water disinfection capability. The natural raw clay material (kaolin) was used as the main ceramic membrane (CM) support. The impact of the number of polyelectrolyte bilayers (2, 4, 6) on the retention of Escherichia coli was systematically investigated. Test results showed the water permeability coefficients (Lp) were 85.3 L/m2.h.bar and 69.5, 28.3, 50.1 L/m2.h.bar for pristine (CM0) and ceramic membranes with two bilayers (CM2), four bilayers (CM4), and six bilayers (CM6), respectively. Complete retention of E. coli was achieved by the multilayer polyelectrolyte ceramic membrane with four bilayers. The surface morphology of the multilayer polyelectrolyte ceramic membrane was identified by scanning electron microscopy (SEM). The results showed that the multilayer polyelectrolyte ceramic membrane can be safely applied in providing water disinfection.

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Biomineralization of Platinum by Escherichia coli

Metals ◽

10.3390/met9040407 ◽

2019 ◽

Vol 9 (4) ◽

pp. 407 ◽

Cited By ~ 3

Author(s):

Sahar Shar ◽

Frank Reith ◽

Esmaeil Shahsavari ◽

Eric Adetutu ◽

Yuana Nurulita ◽

...

Keyword(s):

Escherichia Coli ◽

Liquid Culture ◽

Bacterial Species ◽

Platinum Complexes ◽

Industrial Applications ◽

Bacterial Survival ◽

Platinum Concentration ◽

E Coli ◽

The Impact ◽

Scanning Electron

The widespread use of platinum in many industrial applications has led to its release into the environment at elevated concentrations with potential adverse effects on human and environmental health. However, the nature of interactions between mobile platinum complexes and the biotic components of the environment, which are increasingly being exposed to platinum, is poorly studied. The aim of this study was to assess the impact of Pt(IV)-chloride on the growth and activity of the well-characterized bacteria Escherichia coli. Bacterial survival and viability in the presence of different concentrations of Pt(IV)-chloride were assessed in liquid culture, while platinum retention was assessed using experimentation with sand-filled columns with the residual platinum concentration measured by atomic absorption spectroscopy. Bacterial biomineralization of platinum was studied with scanning electron microscopy. The results showed that E. coli tolerated PtCl4 at concentrations of up to 10,000 µM over 21 days and remained viable after 112 days of incubation with PtCl4 at 10,000 µM in sand columns. Overall, 74 wt.% and 50 wt.% of platinum was mineralized in E. coli and blank sand columns, respectively. The results of this study confirm that E. coli is capable of biomineralizing platinum. The results confirm that the interaction of platinum with bacteria is not limited to known metal-resistant bacterial species.

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Evidence for Escherichia coli O157:H7 Attachment to Water Distribution Pipe Materials by Scanning Electron Microscopy

Journal of Food Protection ◽

10.4315/0362-028x-65.12.1970 ◽

2002 ◽

Vol 65 (12) ◽

pp. 1970-1975 ◽

Cited By ~ 3

Author(s):

MAFU AKIER ASSANTA ◽

DENIS ROY ◽

MARIE-JOSÉE LEMAY ◽

DIANE MONTPETIT

Keyword(s):

Electron Microscopy ◽

Escherichia Coli ◽

Scanning Electron Microscopy ◽

Water Distribution ◽

Escherichia Coli O157 ◽

Exposure Condition ◽

Copper Surfaces ◽

E Coli ◽

Plastic Surfaces ◽

Scanning Electron

Scanning electron microscopy observation was used to investigate the adhesion of Escherichia coli O157:H7 on water distribution pipe surfaces such as copper and polyethylene plastic at different contact times and storage temperatures. Our results indicated that E. coli cells could easily attach to both surface types after exposures as short as 1 or 4 h at ambient (20°C) and refrigeration temperatures (4°C). Also, we found that copper surfaces have a higher number of attached E. coli cells than plastic surfaces. The number of cells attached to each type of material depended on the nature of the water distribution pipe surfaces and the length of contact time. In addition, the surface energy value of each surface estimated by contact angle measurements using water, ∝-bromonaphthalene, and dimethyl sulfoxide as wetting agents showed that both copper (41.2 megajoules [MJ]·m−2) and plastic (45.8 MJ·m−2) have a low energy surface. In no cases could evidence of extracellular material be observed on surfaces with either exposure condition.

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Enterohemorrhagic Escherichia coli O157:H7 Present in Radish Sprouts

Applied and Environmental Microbiology ◽

10.1128/aem.64.4.1532-1535.1998 ◽

1998 ◽

Vol 64 (4) ◽

pp. 1532-1535 ◽

Cited By ~ 173

Author(s):

Yoshinori Itoh ◽

Yoshiko Sugita-Konishi ◽

Fumiko Kasuga ◽

Masaaki Iwaki ◽

Yukiko Hara-Kudo ◽

...

Keyword(s):

Electron Microscopy ◽

Escherichia Coli ◽

Scanning Electron Microscopy ◽

Outer Surface ◽

Immunofluorescence Microscopy ◽

Enterohemorrhagic Escherichia Coli ◽

Escherichia Coli O157 ◽

E Coli ◽

Radish Sprouts ◽

Scanning Electron

ABSTRACT Using cultivation, immunofluorescence microscopy, and scanning electron microscopy, we demonstrated the presence of viable enterohemorrhagic Escherichia coli O157:H7 not only on the outer surfaces but also in the inner tissues and stomata of cotyledons of radish sprouts grown from seeds experimentally contaminated with the bacterium. HgCl2 treatment of the outer surface of the hypocotyl did not kill the contaminating bacteria, which emphasized the importance of either using seeds free from E. coli O157:H7 in the production of radish sprouts or heating the sprouts before they are eaten.

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SINTESIS DAN KARAKTERISASI NANOPARTIKEL CuFe2O4 SERTA APLIKASINYA SEBAGAI ANTIBAKTERI

CHEMISTRY PROGRESS ◽

10.35799/cp.12.2.2019.27929 ◽

2020 ◽

Vol 12 (2) ◽

Author(s):

Almendo G. Lasera ◽

Henry Aritonang ◽

Harry Koleangan

Keyword(s):

Electron Microscopy ◽

Escherichia Coli ◽

Scanning Electron Microscopy ◽

Staphylococcus Aureus ◽

Antibacterial Activity ◽

Gram Negative Bacteria ◽

E Coli ◽

Activity Test ◽

Sem Imaging ◽

Scanning Electron

ABSTRAKNanopartikel CuFe2O4 disintesis menggunakan metode kopresipitasi. Material yang telah disintesis, kemudian dikarakterisasi dengan menggunakan Scanning Electron Microscopy (SEM) dan Xray-Diffraction (XRD) serta di uji aktifitasnya sebagai antibakteri dengan menggunakan bakteri Staphylococcus aureus (Gram positif) dan Escherichia coli (Gram negatif). Hasil citra SEM memperlihatkan morfologi nanopartikel CuFe2O4 berbentuk persegi yang tidak beraturan. Difraktogram XRD menunjukkan bahwa ukuran sampel CuFe2O4 yang diperoleh adalah sebesar 20,136 nm. Uji aktifitas antibakteri yang telah dilakukan menunjukkan bahwa, nanopartikel CuFe2O4 jauh lebih baik dalam menghambat pertumbuhan bakteri E. coli dibandingkan dengan bakteri S.aureus, masing-masing 24 mm dan 6,5 mm. ABSTRACTCuFe2O4 nanoparticles were synthesized using the coprecipitation method. The synthesized material was then characterized using Scanning Electron Microscopy (SEM) and Xray-Difraction (XRD) and tested as antibacterial activity using Staphylococcus aureus (Gram positive) and Escherichia coli (Gram negative) bacteria. SEM imaging showed morphology of CuFe2O4 nanoparticles shaped like a rod. XRD diffractogram showed that the size of CuFe2O4 nanoparticles that obtained at 20.13 nm. The antibacterial activity test that has been done shows, CuFe2O4 nanoparticles are much better in inhibiting the growth of E. coli bacteria compared with S. aureus bacteria, 24 mm and 6,5 respertivelly.

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Impact of the contamination time by Escherichia coli on biofilm formation in surgical instruments

Revista Brasileira de Enfermagem ◽

10.1590/0034-7167-2020-0759 ◽

2021 ◽

Vol 74 (3) ◽

Author(s):

Síntia de Souza Evangelista ◽

Simone Gonçalves dos Santos ◽

Adriana Cristina de Oliveira

Keyword(s):

Electron Microscopy ◽

Escherichia Coli ◽

Scanning Electron Microscopy ◽

Biofilm Formation ◽

Surgical Instruments ◽

Microbial Load ◽

Surgical Instrument ◽

E Coli ◽

Over Time ◽

Scanning Electron

ABSTRACT Objectives: to evaluate the microbial load and adherence of Escherichia coli in different areas of the surgical instrument surface exposed to experimental contamination over time. Methods: experimental study in which fragments of crile forceps (serrated, rod and rack) were contaminated by immersion in Tryptic Soy Broth, containing 106 CFU/mL of E. coli, for 1, 2, 4, 6, 8, 12 and 24 hours. Microbial load and bacterial adherence were evaluated using microbiological culture and scanning electron microscopy, respectively. Results: there was an increase in the microbial load on the surgical instrument, proportional to the contamination interval, ranging from 102 after 1 hour to 105 CFU/cm2 in 24 hours. The presence of exopolysaccharide was detected after two hours of contamination. Conclusions: microbial load and adhesion of E. coli increased over time, reaching 105 CFU/cm2 after 24 hours of contamination, starting biofilm formation after two hours.

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Relative Efficacy of Sodium Hypochlorite Wash Versus Irradiation To Inactivate Escherichia coli O157:H7 Internalized in Leaves of Romaine Lettuce and Baby Spinach†

Journal of Food Protection ◽

10.4315/0362-028x-70.11.2526 ◽

2007 ◽

Vol 70 (11) ◽

pp. 2526-2532 ◽

Cited By ~ 60

Author(s):

BRENDAN A. NIEMIRA

Keyword(s):

Electron Microscopy ◽

Escherichia Coli ◽

Ionizing Radiation ◽

Sodium Hypochlorite ◽

Escherichia Coli O157 ◽

Romaine Lettuce ◽

E Coli ◽

Perfusion Process ◽

Scanning Electron ◽

Spinach Leaves

Pathogenic bacteria that become internalized in leaf tissues are protected from the antimicrobial effects of surface treatments. Ionizing radiation is known to penetrate food tissues, but the efficacy of the process against internalized bacteria is unknown. Leaves of Romaine lettuce and baby spinach were cut into pieces, submerged in a cocktail mixture of three isolates of Escherichia coli O157:H7, and subjected to a vacuum perfusion process to force the bacterial cells into the intercellular spaces in the leaves. Scanning electron microscopy was used to evaluate the efficacy of the perfusion process. The inoculated leaves were then treated with a 3-min water wash, a 3-min wash with a sodium hypochlorite sanitizing solution (300 or 600 ppm), or various doses of ionizing radiation (0.25 to 1.5 kGy). Leaves were stomached to recover the internalized pathogen cells, which were enumerated. The vacuum perfusion effectively forced bacteria into the leaf vasculature and apoplast, as confirmed by scanning electron microscopy. For spinach leaf pieces, neither the water nor the sodium hypochlorite washes resulted in significant reductions of E. coli O157:H7 cells relative to the untreated control. For Romaine lettuce leaf pieces, 300 and 600 ppm sodium hypochlorite each resulted in less than 1-log reduction; water wash was ineffective. Ionizing radiation, in contrast, significantly reduced the pathogen population, with 4-log (Romaine lettuce) or 3-log (spinach) reductions at the highest dose tested. In Romaine leaves, the reduction was dose dependent across the range of doses tested, with a D10-value (the amount of irradiation necessary to reduce the population by 1 log unit) of 0.39 kGy. In spinach leaves, the pathogen had a biphasic response, with a D10-value of 0.27 kGy in the range of 0 to 0.75 kGy but only slight additional reductions from 0.75 to 1.5 kGy. In this study, ionizing radiation but not chemical sanitizers effectively reduced viable E. coli O157:H7 cells internalized in leafy green vegetables, but the response of the pathogen to irradiation was more complex in spinach leaves than in Romaine lettuce leaves.

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The Protein Interactome of Glycolysis in Escherichia coli

Proteomes ◽

10.3390/proteomes9020016 ◽

2021 ◽

Vol 9 (2) ◽

pp. 16

Author(s):

Shomeek Chowdhury ◽

Stephen Hepper ◽

Mudassir K. Lodi ◽

Milton H. Saier ◽

Peter Uetz

Keyword(s):

Escherichia Coli ◽

Protein Interactions ◽

Allosteric Regulation ◽

Glycolytic Enzymes ◽

Protein Protein Interactions ◽

Post Translational Modification ◽

Interacting Protein ◽

E Coli ◽

Protein Interactome ◽

The Impact

Glycolysis is regulated by numerous mechanisms including allosteric regulation, post-translational modification or protein-protein interactions (PPI). While glycolytic enzymes have been found to interact with hundreds of proteins, the impact of only some of these PPIs on glycolysis is well understood. Here we investigate which of these interactions may affect glycolysis in E. coli and possibly across numerous other bacteria, based on the stoichiometry of interacting protein pairs (from proteomic studies) and their conservation across bacteria. We present a list of 339 protein-protein interactions involving glycolytic enzymes but predict that ~70% of glycolytic interactors are not present in adequate amounts to have a significant impact on glycolysis. Finally, we identify a conserved but uncharacterized subset of interactions that are likely to affect glycolysis and deserve further study.

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Solubility assessment of single-chain antibody fragment against epithelial cell adhesion molecule extracellular domain in four Escherichia coli strains

Journal of Genetic Engineering and Biotechnology ◽

10.1186/s43141-021-00126-1 ◽

2021 ◽

Vol 19 (1) ◽

Author(s):

Fatemeh Sadat Javadian ◽

Majid Basafa ◽

Aidin Behravan ◽

Atieh Hashemi

Keyword(s):

Escherichia Coli ◽

Cell Adhesion ◽

Epithelial Cell ◽

Adhesion Molecule ◽

Cell Adhesion Molecule ◽

Extracellular Domain ◽

Epithelial Cell Adhesion Molecule ◽

Single Chain ◽

E Coli ◽

The Impact

Abstract Background Overexpression of the EpCAM (epithelial cell adhesion molecule) in malignancies makes it an attractive target for passive immunotherapy in a wide range of carcinomas. In comparison with full-length antibodies, due to the small size, the scFvs (single-chain variable fragments) are more suitable for recombinant expression in E. coli (Escherichia coli). However, the proteins expressed in large amounts in E. coli tend to form inclusion bodies that need to be refolded which may result in poor recovery of bioactive proteins. Various engineered strains were shown to be able to alleviate the insolubility problem. Here, we studied the impact of four E. coli strains on the soluble level of anti-EpEX-scFv (anti-EpCAM extracellular domain-scFv) protein. Results Although results showed that the amount of soluble anti-EpEX-scFv obtained in BL21TM (DE3) (114.22 ± 3.47 mg/L) was significantly higher to those produced in the same condition in E. coli RosettaTM (DE3) (71.39 ± 0.31 mg/L), and OrigamiTM T7 (58.99 ± 0.44 mg/L) strains, it was not significantly different from that produced by E. coli SHuffleTM T7 (108.87 ± 2.71 mg/L). Furthermore, the highest volumetric productivity of protein reached 318.29 ± 26.38 mg/L in BL21TM (DE3). Conclusions Although BL21TM (DE3) can be a suitable strain for high-level production of anti-EpEX-scFv protein, due to higher solubility yield (about 55%), E. coli SHuffleTM T7 seems to be better candidate for soluble production of scfv compared to BL21TM (DE3) (solubility yield of about 30%).

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Effect of inorganic nanofillers on the impact behavior and fracture probability of industrial high-density polyethylene nanocomposite

Journal of Composite Materials ◽

10.1177/0021998317746477 ◽

2017 ◽

Vol 52 (18) ◽

pp. 2431-2442 ◽

Cited By ~ 4

Author(s):

Harun Sepet ◽

Necmettin Tarakcioglu ◽

RDK Misra

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

High Density Polyethylene ◽

Fracture Probability ◽

High Density ◽

Impact Behavior ◽

Inorganic Filler ◽

Melt Mixing ◽

The Impact ◽

Scanning Electron

The main purpose of this work is to study how the morphology of nanofillers and dispersion and distribution level of inorganic nanofiller influence the impact behavior and fracture probability of inorganic filler filled industrial high-density polyethylene nanocomposites. For this study, nanoclay and nano-CaCO3 fillers–high-density polyethylene mixings (0, 1, 3, 5 wt.% high-density polyethylene) was prepared by melt-mixing method using a compounder system. The impact behavior was examined by charpy impact test, scanning electron microscopy, and probability theory and statistics. The level of the dispersion was characterized with scanning electron microscopy energy dispersive X-ray spectroscopy analysis. The results showed rather good dispersion of both of inorganic nanofiller, with a mixture of exfoliated and confined morphology. The results indicated that the impact strength of the industrial nanocomposite decreased with the increase of inorganic particulate content. The impact reliability of the industrial nanocomposites depends on the type of nanofillers and their dispersion and distribution in the matrix.

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Impact of Vacuum Cooling on Escherichia coli O157:H7 Infiltration into Lettuce Tissue

Applied and Environmental Microbiology ◽

10.1128/aem.02811-07 ◽

2008 ◽

Vol 74 (10) ◽

pp. 3138-3142 ◽

Cited By ~ 57

Author(s):

Haiping Li ◽

Mehrdad Tajkarimi ◽

Bennie I. Osburn

Keyword(s):

Escherichia Coli ◽

Risk Assessment ◽

Reduction Rate ◽

Escherichia Coli O157 ◽

Surface Sterilization ◽

E Coli ◽

Green Industry ◽

Vacuum Cooling ◽

The Impact

ABSTRACT Vacuum cooling is a common practice in the California leafy green industry. This study addressed the impact of vacuum cooling on the infiltration of Escherichia coli O157:H7 into lettuce as part of the risk assessment responding to the E. coli O157:H7 outbreaks associated with leafy green produce from California. Vacuum cooling significantly increased the infiltration of E. coli O157:H7 into the lettuce tissue (2.65E+06 CFU/g) compared to the nonvacuumed condition (1.98E+05 CFU/g). A stringent surface sterilization and quadruple washing could not eliminate the internalized bacteria from lettuce. It appeared that vacuuming forcibly changed the structure of lettuce tissue such as the stomata, suggesting a possible mechanism of E. coli O157:H7 internalization. Vacuuming also caused a lower reduction rate of E. coli O157:H7 in stored lettuce leaves than that for the nonvacuumed condition.

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