scholarly journals The interaction of Ag2O nanoparticles with Escherichia coli: inhibition–sterilization process

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Danqing Li ◽  
Shuai Chen ◽  
Ke Zhang ◽  
Nan Gao ◽  
Miao Zhang ◽  
...  
Keyword(s):  
Antibacterial Agents ◽  
Spectroscopic Analysis ◽  
Density Measurement ◽  
Electronic Microscopy ◽  
E Coli ◽  
High Antibacterial Activity ◽  
Infrared Spectroscopic Analysis ◽  
Optical Density Measurement ◽  
Sterilization Process ◽  
Ag2o Nanoparticles

AbstractSilver-based antibacterial agents have obtained wide attention due to the fact that bacteria in the environment is ubiquitous, which has become one of the most difficult problems for human health. However, the antibacterial mechanism and process are still inconclusive. Here, Ag2O nanoparticles (NPs) with uniform spherical morphology and small size (around 30 nm) were prepared. The as-prepared Ag2O NPs induced high antibacterial activity (100% inhibition ratio) against E. coli. A two-step antibacterial process was proposed and confirmed, which divided into inhibition and sterilization steps. The optical density measurement, malondialdehyde concentration detection, morphologic imaging with electronic microscopy and Fourier transform infrared spectroscopic analysis unveiled the interaction of Ag2O NPs with E. coli, which verified the inhibition–sterilization process we proposed.

scholarly journals 5-Bromo-1-(4-chlorobenzyl)-1H-indole-2-carboxamides as new potent antibacterial agents

2018 ◽  
Vol 24 (6) ◽  
pp. 327-332 ◽  
Author(s):  
Yogesh D. Mane ◽  
Smita S. Patil ◽  
Dhanraj O. Biradar ◽  
Bhimrao C. Khade
Keyword(s):  
Escherichia Coli ◽  
Antibacterial Activity ◽  
Antibacterial Agents ◽  
Inhibitory Concentration ◽  
Antibacterial Activities ◽  
Gram Negative Bacteria ◽  
Internal Standards ◽  
Gram Negative ◽  
E Coli ◽  
High Antibacterial Activity

Abstract Ten 5-bromoindole-2-carboxamides were synthesized, characterized and evaluated for antibacterial activity against pathogenic Gram-negative bacteria Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa and Salmonella Typhi using gentamicin and ciprofloxacin as internal standards. Compounds 7a–c, 7g and 7h exhibit high antibacterial activity with a minimum inhibitory concentration (MIC) of 0.35–1.25 μg/mL. Compounds 7a–c exhibit antibacterial activities that are higher than those of the standards against E. coli and P. aeruginosa.

scholarly journals Spectroscopic and Biophysical Studies on Chalcones and Schiff Bases Derived from Chromen-2-one and Quinoline-2(1H)-one Derivatives as Antibacterial Agents

2020 ◽  
Vol 32 (7) ◽  
pp. 1719-1727
Author(s):  
Saad H. Alotaibi
Keyword(s):  
13C Nmr ◽  
Dna Cleavage ◽  
Antibacterial Agents ◽  
Spectroscopic Analysis ◽  
Docking Studies ◽  
The Other ◽  
Moderate Activity ◽  
Bacterial Strains ◽  
E Coli ◽  
Biophysical Studies

A series of chalcone derivatives and arylidene analogues derived from 3-acetyl coumarin were synthesized. The synthesized compounds were elucidated by spectroscopic analysis such as elemental analysis, infrared, 1H & 13C NMR and mass spectroscopies, and then the synthesized compounds were purified and tested against three bacterial strains. Compound 9c showed high activity against E. coli and P. aeruginosa. Compounds 4 and 6a showed moderate activity against E. coli while compounds 6a, 6b and 9c showed moderate activity against S. aureus. The reference antibiotics were tested against the same bacteria strains in the same conditions and showed that ciprofloxacin have positive activity against P. aeruginosa and S. aureus but it shows negative activity against E. coli while amoxicillin have positive activity against S. aureus and negative activity against E. coli and P. aeruginosa. On the other hand, vancomycin has positive activity against P. aeruginosa but not tested against E. coli and S. aureus. Staph strains were treated with compounds 4 and 7 on DNA fragmentation and DNA cleavage. Docking studies of synthesized compound 9c was determined and the results were compared with ampicillin. Finally, UV and fluorescence analyses of the synthesized compounds (3, 4, 6b, 6c, 6e, 7, 9c and 9e) were also conducted.

Synthesis, Characterization and Biological Evaluation of Some 2-[1-(1,3-Diphenyl-1HPyrazol-4-yl)-meth-(E)-ylidene]indan-1-one Derivatives as Antibacterial Agents

2020 ◽  
Vol 5 (2) ◽  
pp. 127-132
Author(s):  
Uttam B. Chougule ◽  
Hemant V. Chavan ◽  
Savita R. Dhongade
Keyword(s):  
Reaction Time ◽  
Antibacterial Agents ◽  
Spectroscopic Analysis ◽  
Knoevenagel Condensation ◽  
Biological Evaluation ◽  
Bacterial Strains ◽  
Short Reaction Time ◽  
E Coli ◽  
Time Structures ◽  
Substituted 1

A new series of 2-[1-(1,3-diphenyl-1H-pyrazol-4-yl)-meth-(E)-ylidene]-indan-1-one derivatives (5a-l) have been synthesized through through the Knoevenagel condensation of pyrazole carbaldehydes with differently substituted 1-indanone derivatives in the presence of base. A high yielding and solvent-free method was developed for the synthesis of hydrazones from acetophenones under microwave irradiation in a very short reaction time. Structures of the newly synthesized compounds were affirmed by IR, 1H & 13C NMR and mass spectroscopic analysis. The confirmed structures were screened for their antibacterial potency against S. aureus and E. coli bacterial strains. Among the series, compounds 5b, 5c and 5f were evoked as potent antibacterial agents

scholarly journals SOFT CORAL (Sinularia sp.) EXTRACTS WITH ANTIBACTERIAL ACTIVITY

Omni-Akuatika ◽  
2018 ◽  
Vol 14 (1) ◽  
Author(s):  
Wendy Alexander Tanod ◽  
Anita Treisya Aristawati ◽  
Masteria Yunovilsa Putra ◽  
Muliadin Muliadin
Keyword(s):  
Antibacterial Activity ◽  
Pathogenic Bacteria ◽  
Antibacterial Agents ◽  
Soft Coral ◽  
Solvent Polarity ◽  
Soft Corals ◽  
Bacterial Strains ◽  
E Coli ◽  
High Antibacterial Activity ◽  
And Staphylococcus Aureus

There is a growing need for new antibacterial agents, in particular because many antibiotics are becoming ineffective due to the emergence of resistant bacterial strains. Soft corals of the Genus Sinularia, Family Alcyoniidae, have potential as a source of terpenoid and steroid compounds with antibacterial activity. These corals may vary in external morphology (shape, colour, size).The aim of this research was to identify extracted fractions with high antibacterial activity. Sinularia sp. specimens were extracted, fractionated based on solvent polarity, and tested for antibacterial bioactivity against pathogenic bacteria (Escherichia coli and Staphylococcus aureus). Antibacterial activity of the three fractions varied in strength. The dichloromethane fraction showed strong antibacterial activity, inhibiting S. aureus and E. coli growth at a concentration of 1 mg ml-1, while the ethyl acetate and ethanol fractions were effective at 10 mg ml-1 and 100 mg ml-1, respectively.

The role of the macular pigment optical density measurement in the diagnosis of eye diseases

2016 ◽  
Vol 16 (4) ◽  
pp. 197-200
Author(s):  
E.N. Eskina ◽  
◽  
E.A. Egorov ◽  
A.V. Belogurova ◽  
А.А. Gvetadze ◽  
...  
Keyword(s):  
Optical Density ◽  
Density Measurement ◽  
Macular Pigment ◽  
Eye Diseases ◽  
Macular Pigment Optical Density ◽  
Optical Density Measurement

Large-scale High-throughput Screening Revealed 5'-(carbonylamino)-2,3'- bithiophene-4'-carboxylate as Novel Template for Antibacterial Agents

2020 ◽  
Vol 17 (5) ◽  
pp. 716-724
Author(s):  
Yan A. Ivanenkov ◽  
Renat S. Yamidanov ◽  
Ilya A. Osterman ◽  
Petr V. Sergiev ◽  
Vladimir A. Aladinskiy ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
High Throughput ◽  
High Throughput Screening ◽  
Large Scale ◽  
Antibacterial Agents ◽  
Sos Response ◽  
Luciferase Assay ◽  
Translational Machinery ◽  
E Coli ◽  
New Class

Background: The key issue in the development of novel antimicrobials is a rapid expansion of new bacterial strains resistant to current antibiotics. Indeed, World Health Organization has reported that bacteria commonly causing infections in hospitals and in the community, e.g. E. Coli, K. pneumoniae and S. aureus, have high resistance vs the last generations of cephalosporins, carbapenems and fluoroquinolones. During the past decades, only few successful efforts to develop and launch new antibacterial medications have been performed. This study aims to identify new class of antibacterial agents using novel high-throughput screening technique. Methods: We have designed library containing 125K compounds not similar in structure (Tanimoto coeff.< 0.7) to that published previously as antibiotics. The HTS platform based on double reporter system pDualrep2 was used to distinguish between molecules able to block translational machinery or induce SOS-response in a model E. coli system. MICs for most active chemicals in LB and M9 medium were determined using broth microdilution assay. Results: In an attempt to discover novel classes of antibacterials, we performed HTS of a large-scale small molecule library using our unique screening platform. This approach permitted us to quickly and robustly evaluate a lot of compounds as well as to determine the mechanism of action in the case of compounds being either translational machinery inhibitors or DNA-damaging agents/replication blockers. HTS has resulted in several new structural classes of molecules exhibiting an attractive antibacterial activity. Herein, we report as promising antibacterials. Two most active compounds from this series showed MIC value of 1.2 (5) and 1.8 μg/mL (6) and good selectivity index. Compound 6 caused RFP induction and low SOS response. In vitro luciferase assay has revealed that it is able to slightly inhibit protein biosynthesis. Compound 5 was tested on several archival strains and exhibited slight activity against gram-negative bacteria and outstanding activity against S. aureus. The key structural requirements for antibacterial potency were also explored. We found, that the unsubstituted carboxylic group is crucial for antibacterial activity as well as the presence of bulky hydrophobic substituents at phenyl fragment. Conclusion: The obtained results provide a solid background for further characterization of the 5'- (carbonylamino)-2,3'-bithiophene-4'-carboxylate derivatives discussed herein as new class of antibacterials and their optimization campaign.

scholarly journals Apomorphine Targets the Pleiotropic Bacterial Regulator Hfq

Antibiotics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 257
Author(s):  
Florian Turbant ◽  
David Partouche ◽  
Omar El Hamoui ◽  
Sylvain Trépout ◽  
Théa Legoubey ◽  
...  
Keyword(s):  
Small Rnas ◽  
Antibacterial Agents ◽  
Amyloid Fibrils ◽  
Noncoding Rnas ◽  
Amyloid Formation ◽  
Gram Negative Bacteria ◽  
Translation Efficiency ◽  
Gram Negative ◽  
Bacterial Adaptation ◽  
E Coli

Hfq is a bacterial regulator with key roles in gene expression. The protein notably regulates translation efficiency and RNA decay in Gram-negative bacteria, thanks to its binding to small regulatory noncoding RNAs. This property is of primary importance for bacterial adaptation and survival in hosts. Small RNAs and Hfq are, for instance, involved in the response to antibiotics. Previous work has shown that the E. coli Hfq C-terminal region (Hfq-CTR) self-assembles into an amyloid structure. It was also demonstrated that the green tea compound EpiGallo Catechin Gallate (EGCG) binds to Hfq-CTR amyloid fibrils and remodels them into nonamyloid structures. Thus, compounds that target the amyloid region of Hfq may be used as antibacterial agents. Here, we show that another compound that inhibits amyloid formation, apomorphine, may also serve as a new antibacterial. Our results provide an alternative in order to repurpose apomorphine, commonly used in the treatment of Parkinson’s disease, as an antibiotic to block bacterial adaptation to treat infections.

scholarly journals Polyphenylglyoxamide-Based Amphiphilic Small Molecular Peptidomimetics as Antibacterial Agents with Anti-Biofilm Activity

2021 ◽  
Vol 22 (14) ◽  
pp. 7344
Author(s):  
Tsz Tin Yu ◽  
Rajesh Kuppusamy ◽  
Muhammad Yasir ◽  
Md. Musfizur Hassan ◽  
Manjulatha Sara ◽  
...  
Keyword(s):  
Quaternary Ammonium ◽  
Antibacterial Agents ◽  
Health Concern ◽  
Resistant Bacteria ◽  
Ammonium Iodide ◽  
E Coli ◽  
Drug Resistant Bacteria ◽  
Permeability Study ◽  
Cationic Group ◽  
Chain Lengths

The rapid emergence of drug-resistant bacteria is a major global health concern. Antimicrobial peptides (AMPs) and peptidomimetics have arisen as a new class of antibacterial agents in recent years in an attempt to overcome antibiotic resistance. A library of phenylglyoxamide-based small molecular peptidomimetics was synthesised by incorporating an N-alkylsulfonyl hydrophobic group with varying alkyl chain lengths and a hydrophilic cationic group into a glyoxamide core appended to phenyl ring systems. The quaternary ammonium iodide salts 16d and 17c showed excellent minimum inhibitory concentration (MIC) of 4 and 8 μM (2.9 and 5.6 μg/mL) against Staphylococcus aureus, respectively, while the guanidinium hydrochloride salt 34a showed an MIC of 16 μM (8.5 μg/mL) against Escherichia coli. Additionally, the quaternary ammonium iodide salt 17c inhibited 70% S. aureus biofilm formation at 16 μM. It also disrupted 44% of pre-established S. aureus biofilms at 32 μM and 28% of pre-established E. coli biofilms 64 μM, respectively. A cytoplasmic membrane permeability study indicated that the synthesised peptidomimetics acted via disruption and depolarisation of membranes. Moreover, the quaternary ammonium iodide salts 16d and 17c were non-toxic against human cells at their therapeutic dosages against S. aureus.

scholarly journals Synthesis and In Vitro Antimicrobial Evaluation of Photoactive Multi—Block Chalcone Conjugate Phthalimide and 1,8-Naphthalimide Novolacs

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1859
Author(s):  
Periyan Durairaju ◽  
Chinnasamy Umarani ◽  
Govindasami Periyasami ◽  
Perumberkandigai Adikesavan Vivekanand ◽  
Mostafizur Rahaman
Keyword(s):  
Spectroscopic Analysis ◽  
Photophysical Properties ◽  
Gel Permeation Chromatography ◽  
13C Nmr Spectroscopy ◽  
Antimicrobial Activities ◽  
Microbial Activities ◽  
E Coli ◽  
Molecular Weights ◽  
Antimicrobial Evaluation

Herein we report new multiblock chalcone conjugate phthalimide and naphthalimide functionalized copolymers with a topologically novel architecture synthesis using nucleophilic substitution and polycondensation methodology. The structures of the synthesized novolacs were elucidated on the basis of their spectroscopic analysis including FTIR, 1H NMR, and 13C NMR spectroscopy. Further, the number-average and weight-average molecular weights of the novolac polymers were determined by gel permeation chromatography (GPC). We examined the solubility of the synthesized polymers in various organic solvents including CHCl3, CH3CN, THF, H2O, CH3OH, DMSO, and DMF and found they are insoluble in both methanol and water. The novolac polymers were evaluated for their photophysical properties and microbial activities. The investigation of the antimicrobial activities of these polymers reveals significant antimicrobial activity against the pathogens E. coli, S. aureus, C. albicans, and A. niger.

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