scholarly journals Antibacterial Filtration Using Polyethylene Terephthalate Filters Coated with Copper Nanoparticles

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Vinh Tien Nguyen ◽  
Quang Hoang Anh Vu ◽  
Thi Ngoc Nhi Pham ◽  
Khanh Son Trinh
Keyword(s):  
Escherichia Coli ◽  
Polyethylene Terephthalate ◽  
Copper Nanoparticles ◽  
Colorimetric Method ◽  
Sodium Hypophosphite ◽  
Bacterial Cells ◽  
Sem Images ◽  
Point Of Use ◽  
Icp Ms ◽  
The One

The purpose of this study is to produce antibacterial filters based on a commercial polyethylene terephthalate (PET) filter with pores larger than bacterial cells. The antibacterial agent was copper nanoparticles (CuNP) which were synthesized and deposited on the PET filter by reducing copper(II) ions using sodium hypophosphite (NaH2PO2) as the reducing agent and polyvinylpyrrolidone (PVP) as the capping agent. Scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy confirmed the presence of 150–300 nm CuNP on the surface of PET filters. We evaluated the amounts of deposited CuNP using a colorimetric method and the antibacterial-filtration capacity of CuNP/PET filters against Escherichia coli using the colony counting method. The reaction conditions were optimized successively using the one-factor-at-a-time approach for the concentration of copper precursor, the concentration of PVP, and the reaction time. The results showed that an initial 1 M CuSO4, 0.8% w / v PVP, and 10-20 min of reaction resulted in a CuNP/PET filter with the highest antibacterial activity: 5.2 log cfu/mL reduction for Escherichia coli and 5.6 log cfu/mL reduction or Staphylococcus aureus. SEM images demonstrated the damages of the bacterial cells after passing through the CuNP/PET filter. ICP-MS analysis of the first liter of filtrate showed that the copper concentration of released copper was 0.6 ± 0.1  ppm, which is below the WHO standard for drinking water. Therefore, these CuNP/PET filters are promising for point-of-use disinfection of water, where clean potable water is not sufficient.

scholarly journals Bioreduction and Bioremoval of Hexavalent Chromium by Genetically Engineered Strains (Escherichia Coli MT2A and Escherichia Coli MT3)

2021 ◽  
Author(s):  
Şeyma Akkurt ◽  
Merve Oğuz ◽  
Aysel Alkan Uçkun
Keyword(s):  
Escherichia Coli ◽  
Electron Microscope ◽  
Aqueous Solutions ◽  
Hexavalent Chromium ◽  
Effective Strain ◽  
Scanning Transmission Electron Microscope ◽  
Genetically Engineered ◽  
High Rate ◽  
Bacterial Cells ◽  
Sem Images

Abstract Studies on the removal of toxic metals from water by genetic engineering applications are becoming more and more diverse. Especially by the expression of cysteine and thiol rich proteins such as metallothioneins in bacterial cells, a high rate of removal of metal ions from the environment is ensured. In this study, we evaluated the removal and reduction of hexavalent chromium Cr(VI)from aqueous solutions with the recombinant strains obtained by cloning the human metallothioneinsMT2A and MT3 into Escherichia coli Jm109.E. coli MT2A was the most effective strain in both Cr(VI) removal (89%in 25 mg/L Cr(VI) application) and Cr(VI) reduction (76%in 25 mg/L Cr(VI) application).Cr(VI) adsorbed per dry cell (at 25 mg/L) were 17 mg/g, 22 mg/g and 19 mg/g for Jm109, MT2A and MT3, respectively. Scanning electron microscope (SEM) images showed that the morphological structures of Cr(VI)treated cells were significantly damaged compared to control cells. Scanning transmission electron microscope (STEM) images showed black spots in the cytoplasm of cells treated with Cr(VI).From the shifts in the Fourier transform infrared spectroscopy analysis (FTIR) spectra of the cells treated with Cr(VI) compared to the control cells, it was determined that the groups interacting with Cr were amino, hydroxyl, methyl and sulfhydryl. When all these experimental data were evaluated together, it was concluded that all three species were effective in removing Cr(VI) from aqueous solutions and MT2A strain could be used as the most effective biotechnological tool.

Mechanisms involved in effects of antimicrobial peptides, bactenectins ChBac3.4, ChBac5, and mini-ChBac7.5Nb, on bacterial cells

2017 ◽  
pp. 43-50
Author(s):  
О.В. Шамова ◽  
М.С. Жаркова ◽  
П.М. Копейкин ◽  
Д.С. Орлов ◽  
Е.А. Корнева
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Activity ◽  
Innate Immunity ◽  
Infectious Diseases ◽  
Metabolic Activity ◽  
Capra Hircus ◽  
Bacterial Cells ◽  
Antibiotic Resistant ◽  
Resistant Strains

Антимикробные пептиды (АМП) системы врожденного иммунитета - соединения, играющие важную роль в патогенезе инфекционных заболеваний, так как обладают свойством инактивировать широкий спектр патогенных бактерий, обеспечивая противомикробную защиту живых организмов. В настоящее время АМП рассматриваются как потенциальные соединения-корректоры инфекционной патологии, вызываемой антибиотикорезистентными бактериями (АБР). Цель данной работы состояла в изученим механизмов антибактериального действия трех пептидов, принадлежащих к семейству бактенецинов - ChBac3.4, ChBac5 и mini-ChBac7.5Nb. Эти химически синтезированные пептиды являются аналогами природных пролин-богатых АМП, обнаруженных в лейкоцитах домашней козы Capra hircus и проявляющих высокую антимикробную активность, в том числе и в отношении грамотрицательных АБР. Методы. Минимальные ингибирующие и минимальные бактерицидные концентрации пептидов (МИК и МБК) определяли методом серийных разведений в жидкой питательной среде с последующим высевом на плотную питательную среду. Эффекты пептидов на проницаемость цитоплазматической мембраны бактерий для хромогенного маркера исследовали с использованием генетически модифицированного штамма Escherichia coli ML35p. Действие бактенецинов на метаболическую активность бактерий изучали с применением маркера резазурина. Результаты. Показано, что все исследованные пептиды проявляют высокую антимикробную активность в отношении Escherichia coli ML35p и антибиотикоустойчивых штаммов Escherichia coli ESBL и Acinetobacter baumannii in vitro, но их действие на бактериальные клетки разное. Использован комплекс методик, позволяющих наблюдать в режиме реального времени динамику действия бактенецинов в различных концентрациях (включая их МИК и МБК) на барьерную функцию цитоплазматической мембраны и на интенсивность метаболизма бактериальных клеток, что дало возможность выявить различия в характере воздействия бактенецинов, отличающихся по структуре молекулы, на исследуемые микроорганизмы. Установлено, что действие каждого из трех исследованных бактенецинов в бактерицидных концентрациях отличается по эффективности нарушения целостности бактериальных мембран и в скорости подавления метаболизма клеток. Заключение. Полученная информация дополнит существующие фундаментальные представления о механизмах действия пролин-богатых пептидов врожденного иммунитета, а также послужит основой для биотехнологических исследований, направленных на разработку на базе этих соединений новых антибиотических препаратов для коррекции инфекционных заболеваний, вызываемых АБР и являющимися причинами тяжелых внутрибольничных инфекций. Antimicrobial peptides (AMPs) of the innate immunity are compounds that play an important role in pathogenesis of infectious diseases due to their ability to inactivate a broad array of pathogenic bacteria, thereby providing anti-microbial host defense. AMPs are currently considered promising compounds for treatment of infectious diseases caused by antibiotic-resistant bacteria. The aim of this study was to investigate molecular mechanisms of the antibacterial action of three peptides from the bactenecin family, ChBac3.4, ChBac5, and mini-ChBac7.5Nb. These chemically synthesized peptides are analogues of natural proline-rich AMPs previously discovered by the authors of the present study in leukocytes of the domestic goat, Capra hircus. These peptides exhibit a high antimicrobial activity, in particular, against antibiotic-resistant gram-negative bacteria. Methods. Minimum inhibitory and minimum bactericidal concentrations of the peptides (MIC and MBC) were determined using the broth microdilution assay followed by subculturing on agar plates. Effects of the AMPs on bacterial cytoplasmic membrane permeability for a chromogenic marker were explored using a genetically modified strain, Escherichia coli ML35p. The effect of bactenecins on bacterial metabolic activity was studied using a resazurin marker. Results. All the studied peptides showed a high in vitro antimicrobial activity against Escherichia coli ML35p and antibiotic-resistant strains, Escherichia coli ESBL and Acinetobacter baumannii, but differed in features of their action on bacterial cells. The used combination of techniques allowed the real-time monitoring of effects of bactenecin at different concentrations (including their MIC and MBC) on the cell membrane barrier function and metabolic activity of bacteria. The differences in effects of these three structurally different bactenecins on the studied microorganisms implied that these peptides at bactericidal concentrations differed in their capability for disintegrating bacterial cell membranes and rate of inhibiting bacterial metabolism. Conclusion. The obtained information will supplement the existing basic concepts on mechanisms involved in effects of proline-rich peptides of the innate immunity. This information will also stimulate biotechnological research aimed at development of new antibiotics for treatment of infectious diseases, such as severe in-hospital infections, caused by antibiotic-resistant strains.

scholarly journals Clean one-pot multicomponent synthesis of pyrans using a green and magnetically recyclable heterogeneous nanocatalyst

SynOpen ◽  
2021 ◽  
Author(s):  
Mina Ghassemi ◽  
Ali Maleki
Keyword(s):  
Room Temperature ◽  
Significant Loss ◽  
Copper Ferrite ◽  
Multicomponent Synthesis ◽  
Thermo Gravimetric ◽  
Sem Images ◽  
One Pot ◽  
Three Component Reaction ◽  
Ft Ir ◽  
The One

Copper ferrite (CuFe2O4) magnetic nanoparticles (MNPs) were synthesized via thermal decomposition method and applied as a reusable and green catalyst in the synthesis of functionalized 4H-pyran derivatives using malononitrile, an aromatic aldehyde and a β-ketoester in ethanol at room temperature. Then it was characterized by Fourier transform infrared spectroscopy (FT-IR), energy-dispersive X-ray spectroscopy (EDX) analysis, scanning electron microscopy (SEM) images, thermo gravimetric and differential thermo gravimetric (TGA/DTG) analysis. The catalyst was recovered from the reaction mixture by applying an external magnet and decanting the mixture. Recycled catalyst was reused for several times without significant loss in its activity. Running the one-pot three-component reaction at room temperature, no use of eternal energy source and using a green solvent provide benign, mild, and environmentally friendly reaction conditions; as well, ease of catalyst recovering, catalyst recyclability, no use of column chromatography and good to excellent yields are extra advantages of this work.

scholarly journals Study on the Behavior and Removal of Cadmium and Zinc Using Taraxacum officinale and Gazania under the Application of Biodegradable Chelating Agents

2021 ◽  
Vol 11 (4) ◽  
pp. 1557
Author(s):  
Naoki Kano ◽  
Takumi Hori ◽  
Haixin Zhang ◽  
Naoto Miyamoto ◽  
David Eva Vanessa Anak ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Chelating Agents ◽  
Environmental Control ◽  
Chelating Agent ◽  
Taraxacum Officinale ◽  
Inductively Coupled ◽  
Icp Ms ◽  
Plasma Mass Spectrometry ◽  
Experimental Treatments ◽  
The One

The removal of cadmium (Cd) and zinc (Zn) from soil by phytoremediation was investigated using Taraxacum officinale and Gazania. A plant environmental control system was used to cultivate the plants. The effects of different biodegradable chelating agents (i.e., EDDS, HIDS, and GLDA), relative humidity, and other competitive metals on the adsorption of Cd and Zn were also studied. In addition, the approach for metal recovery was explored by extraction of metals from plants after phytoremediation using Gazania. The concentrations of Cd and Zn were determined by inductively coupled plasma mass spectrometry (ICP-MS). In addition, one-way analysis of variance (ANOVA) tests were performed.to determine significant differences between the experimental treatments adopted in this work. Consequently, the following main conclusions were obtained: (1) In the case of Taraxacum officinale, Cd and Zn could be removed even under the presence of other heavy metals. (2) By adding a chelating agent, the amount absorbed by the shoot generally increased. (3) In the case of Gazania, the concentration of Cd was higher in root than that in shoot, whereas the concentration of Zn was higher in the shoot than that in the root. (4) Taraxacum officinale was more suitable for phytoremediation of Cd than Gazania. (5) Cd and Zn could be extracted from plants by adding a low concentration of nitric acid. (6) The one-way ANOVA tests showed no statistically significant differences among the experimental treatments.

scholarly journals Mechanical and structural properties of composites made from recycled and virgin polyethylene terephthalate (PET) and metal chip or mesh wire

2019 ◽  
Vol 299 ◽  
pp. 06007
Author(s):  
Mircea Aurelian Antoniu Rusu ◽  
Sever-Adrian Radu ◽  
Catalin Moldovan ◽  
Codruta Sarosi ◽  
Ionela Amalia Mazilu (Moldovan) ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Polyethylene Terephthalate ◽  
Processing Parameters ◽  
Sem Images ◽  
Major Drawback ◽  
Recycled Pet ◽  
Plastic Processing ◽  
Metal Chip ◽  
Intense Research ◽  
Properties Of Composites

Although polyethylene terephthalate (PET) is a champion of recycling, intense research is being done to find new solutions for using recycled plastic. This study aims to characterize the mechanical andstructural properties (SEM- scanning electron microscopy) of products made from recycled metal swarf or mesh wire with recycled plastic (PET) in comparison with virgin plastic. Samples manufactured from virgin and recycled PET are made by pressing and high temperature. The loss of mechanical properties ofproducts made from recycled plastic is a major drawback that influences their use. SEM images confirm that the dispersion and distribution of the PET phase is not very uniform. By addition of virgin plastic in various compositions with recycled plastic, processing parameters and mechanical properties can be optimized.

scholarly journals Detection of Engineered Copper Nanoparticles in Soil Using Single Particle ICP-MS

2015 ◽  
Vol 12 (12) ◽  
pp. 15756-15768 ◽  
Author(s):  
Jana Navratilova ◽  
Antonia Praetorius ◽  
Andreas Gondikas ◽  
Willi Fabienke ◽  
Frank von der Kammer ◽  
...  
Keyword(s):  
Copper Nanoparticles ◽  
Single Particle ◽  
Icp Ms

Circumcision Debate

PEDIATRICS ◽  
1986 ◽  
Vol 78 (5) ◽  
pp. 951-951
Author(s):  
MARK L. COHEN
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract Infection ◽  
Urinary Tract ◽  
Tract Infection ◽  
Bladder Mucosa ◽  
Gene Coding ◽  
The One

To the Editor.— It appears that the circumcision pendulum is swinging back, before it even had a chance to swing forth. I am prepared to believe that Wiswell and his colleagues1 will be proved right and that the operation really does protect against urinary tract infection. Although the possibility still exists that the gene coding for the Escherichia coli receptor in bladder mucosa is linked to the one that induces noncircumcision-directed behavior in a parent, I am willing to concede the point.

One-Step Preparation of Competent E. coli: Transformation and Storage of Bacterial Cells in the Same Solution

2021 ◽  
Vol 2021 (11) ◽  
pp. pdb.prot101212 ◽  
Author(s):  
Michael R. Green ◽  
Joseph Sambrook
Keyword(s):  
Escherichia Coli ◽  
Convenient Method ◽  
Plasmid Dna ◽  
Transformation Efficiency ◽  
Bacterial Cells ◽  
E Coli ◽  
One Step ◽  
And Storage

This protocol describes a convenient method for the preparation, use, and storage of competent Escherichia coli. The reported transformation efficiency of this method is ∼5 × 107 transformants/µg of plasmid DNA.

PBP4 and PBP5 are involved in regulating exopolysaccharide synthesis during Escherichia coli biofilm formation

Microbiology ◽  
2021 ◽  
Vol 167 (3) ◽  
Author(s):  
Sathi Mallick ◽  
Shanti Kiran ◽  
Tapas Kumar Maiti ◽  
Anindya S. Ghosh
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
Type Species ◽  
Pentose Phosphate ◽  
Bacterial Cells ◽  
Surface Adhesion ◽  
Content Type ◽  
Penicillin Binding Proteins ◽  
E Coli ◽  
Link Type

Escherichia coli low-molecular-mass (LMM) Penicillin-binding proteins (PBPs) help in hydrolysing the peptidoglycan fragments from their cell wall and recycling them back into the growing peptidoglycan matrix, in addition to their reported involvement in biofilm formation. Biofilms are external slime layers of extra-polymeric substances that sessile bacterial cells secrete to form a habitable niche for themselves. Here, we hypothesize the involvement of Escherichia coli LMM PBPs in regulating the nature of exopolysaccharides (EPS) prevailing in its extra-polymeric substances during biofilm formation. Therefore, this study includes the assessment of physiological characteristics of E. coli CS109 LMM PBP deletion mutants to address biofilm formation abilities, viability and surface adhesion. Finally, EPS from parent CS109 and its ΔPBP4 and ΔPBP5 mutants were purified and analysed for sugars present. Deletions of LMM PBP reduced biofilm formation, bacterial adhesion and their viability in biofilms. Deletions also diminished EPS production by ΔPBP4 and ΔPBP5 mutants, purification of which suggested an increased overall negative charge compared with their parent. Also, EPS analyses from both mutants revealed the appearance of an unusual sugar, xylose, that was absent in CS109. Accordingly, the reason for reduced biofilm formation in LMM PBP mutants may be speculated as the subsequent production of xylitol and a hindrance in the standard flow of the pentose phosphate pathway.

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