Antimicrobial activity of Parthenium hysterophorus against five bacterial strains

In order to develop new antimicrobial agents, a series of 3-formyl indole based Schiff bases were synthesized by reacting 3-formyl indole(indole-3-carboxaldehyde) with substituted aniline taking ethanol as solvent. The reaction was carried in the presence of small amount of p-toluene sulphonic acid as catalyst.All the synthesized compounds were characterized by IR, 1H-NMR spectral analysis. All the synthesized compounds were evaluated for antimicrobial activity against two gram positive bacterial strains (B. subtilisand S. aureus) and two gram negative bacterial strains (P. aeruginosaand E. coli) and one fungal strain (C. albicans). All the synthesized compounds were found to have moderate to good antimicrobial activity. The standard drug amoxicillin, fluconazole were used for antimicrobial activity. Among the synthesized compounds, the maximum antimicrobial activity was shown by compounds GS04, GS07, GS08 and GS10.

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Antimicrobial Activity of Iron-Halide Complexes Against Gram-Positive and Gram-Negative Bacteria

10.26434/chemrxiv.11864934.v1 ◽

2020 ◽

Author(s):

Nusrat Abedin ◽

Abdullah Hamed A Alshehri ◽

Ali M A Almughrbi ◽

Olivia Moore ◽

Sheikh Alyza ◽

...

Keyword(s):

Antimicrobial Activity ◽

Antimicrobial Resistance ◽

Extracellular Dna ◽

Antibiofilm Activity ◽

Gram Negative Bacteria ◽

Bacterial Strains ◽

Gram Positive ◽

Gram Negative ◽

Antimicrobial Substances ◽

Mammalian Cell Lines

Antimicrobial resistance (AMR) has become one of the more serious threats to the global health. The emergence of bacteria resistant to antimicrobial substances decreases the potencies of current antibiotics. Consequently, there is an urgent and growing need for the developing of new classes of antibiotics. Three prepared novel iron complexes have a broad-spectrum antimicrobial activity with minimum bactericidal concentration (MBC) values ranging from 3.5 to 10 mM and 3.5 to 40 mM against Gram-positive and Gram-negative bacteria with antimicrobial resistance phenotype, respectively. Time-kill studies and quantification of the extracellular DNA confirmed the bacteriolytic mode of action of the iron-halide compounds. Additionally, the novel complexes showed significant antibiofilm activity against the tested pathogenic bacterial strains at concentrations lower than the MBC. The cytotoxic effect of the complexes on different mammalian cell lines show sub-cytotoxic values at concentrations lower than the minimum bactericidal concentrations.

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Fabrication and Characterization of Antimicrobial Magnetron Cosputtered TiO2/Ag/Cu Composite Coatings

Coatings ◽

10.3390/coatings11040473 ◽

2021 ◽

Vol 11 (4) ◽

pp. 473

Author(s):

Dilyana Gospodonova ◽

Iliana Ivanova ◽

Todorka Vladkova

Keyword(s):

Antimicrobial Activity ◽

Composite Coatings ◽

Surface Characteristics ◽

Standard Test ◽

Most Probable Number ◽

Bacterial Strains ◽

Probable Number ◽

Fabrication And Characterization

The aim of this study was to prepare TiO2/Ag/Cu magnetron co-sputtered coatings with controlled characteristics and to correlate them with the antimicrobial activity of the coated glass samples. The elemental composition and distribution, surface morphology, wettability, surface energy and its component were estimated as the surface characteristics influencing the bioadhesion. Well expressed, specific, Ag/Cu concentration-dependent antimicrobial activity in vitro was demonstrated toward Gram-negative and Gram-positive standard test bacterial strains both by diffusion 21 assay and by Most Probable Number of surviving cells. Direct contact and eluted silver/coper nanoparticles killing were experimentally demonstrated as a mode of the antimicrobial action of the studied TiO2/Ag/Cu thin composite coatings. It is expected that they would ensure a broad spectrum bactericidal activity during the indwelling of the coated medical devices and for at least 12 h after that, with the supposition that the benefits will be over a longer time.

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Exonuclease VII repairs quinolone-induced damage by resolving DNA gyrase cleavage complexes

Science Advances ◽

10.1126/sciadv.abe0384 ◽

2021 ◽

Vol 7 (10) ◽

pp. eabe0384

Author(s):

Shar-yin N. Huang ◽

Stephanie A. Michaels ◽

Brianna B. Mitchell ◽

Nadim Majdalani ◽

Arnaud Vanden Broeck ◽

...

Keyword(s):

Antimicrobial Activity ◽

Molecular Biology ◽

Excision Repair ◽

Dna Gyrase ◽

Nuclease Activity ◽

Bacterial Strains ◽

Functional Importance ◽

Quinolone Antibiotics ◽

Repair Pathways ◽

Exonuclease Vii

The widely used quinolone antibiotics act by trapping prokaryotic type IIA topoisomerases, resulting in irreversible topoisomerase cleavage complexes (TOPcc). Whereas the excision repair pathways of TOPcc in eukaryotes have been extensively studied, it is not known whether equivalent repair pathways for prokaryotic TOPcc exist. By combining genetic, biochemical, and molecular biology approaches, we demonstrate that exonuclease VII (ExoVII) excises quinolone-induced trapped DNA gyrase, an essential prokaryotic type IIA topoisomerase. We show that ExoVII repairs trapped type IIA TOPcc and that ExoVII displays tyrosyl nuclease activity for the tyrosyl-DNA linkage on the 5′-DNA overhangs corresponding to trapped type IIA TOPcc. ExoVII-deficient bacteria fail to remove trapped DNA gyrase, consistent with their hypersensitivity to quinolones. We also identify an ExoVII inhibitor that synergizes with the antimicrobial activity of quinolones, including in quinolone-resistant bacterial strains, further demonstrating the functional importance of ExoVII for the repair of type IIA TOPcc.

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Characterization and Antibacterial Response of Silver Nanoparticles Biosynthesized Using an Ethanolic Extract of Coccinia indica Leaves

Crystals ◽

10.3390/cryst11020097 ◽

2021 ◽

Vol 11 (2) ◽

pp. 97

Author(s):

Suresh V. Chinni ◽

Subash C. B. Gopinath ◽

Periasamy Anbu ◽

Neeraj Kumar Fuloria ◽

Shivkanya Fuloria ◽

...

Keyword(s):

Electron Microscopy ◽

Antimicrobial Activity ◽

Silver Nanoparticles ◽

Zeta Potential ◽

Ethanolic Extract ◽

Spherical Shape ◽

Bacterial Strains ◽

X Ray ◽

Coccinia Indica ◽

Antibacterial Potential

The present study was planned to characterize and analyze the antimicrobial activity of silver nanoparticles (AgNP) biosynthesized using a Coccinia indica leaf (CIL) ethanolic extract. The present study included the preparation of CIL ethanolic extract using the maceration process, which was further used for AgNP biosynthesis by silver nitrate reduction. Biosynthetic AgNPs were characterized using UV–Visible spectrometry, zeta potential analysis, transmission electron microscopy (TEM), scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), and energy-dispersive X-ray (EDX) spectrometry. The biogenic AgNP and CIL extracts were further investigated against different bacterial strains for their antimicrobial activity. The surface plasmon resonance (SPR) signal at 425 nm confirmed AgNP formation. The SEM and TEM data revealed the spherical shape of biogenic AgNPs and size in the range of 8 to 48 nm. The EDX results verified the presence of Ag. The AgNPs displayed a zeta potential of −55.46 mV, suggesting mild AgNP stability. Compared to Gram-positive bacteria, the biogenic AgNPs demonstrated high antibacterial potential against Gram-negative bacteria. Based on the results, the current study concluded that AgNPs based on CIL extract have strong antibacterial potential, and it established that AgNP biosynthesis using CIL ethanol extract is an effective process.

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Antimicrobial Activity of Cyclic-Monomeric and Dimeric Derivatives of the Snail-Derived Peptide Cm-p5 against Viral and Multidrug-Resistant Bacterial Strains

Biomolecules ◽

10.3390/biom11050745 ◽

2021 ◽

Vol 11 (5) ◽

pp. 745

Author(s):

Melaine González-García ◽

Fidel Morales-Vicente ◽

Erbio Díaz Pico ◽

Hilda Garay ◽

Daniel G. Rivera ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Antimicrobial Activity ◽

Antifungal Activity ◽

Multidrug Resistant ◽

Moderate Activity ◽

Dependent Manner ◽

Bacterial Strains ◽

Acinetobacter Baumanii ◽

Concentration Dependent Manner ◽

Conventional Antibiotics

Cm-p5 is a snail-derived antimicrobial peptide, which demonstrated antifungal activity against the pathogenic strains of Candida albicans. Previously we synthetized a cyclic monomer as well as a parallel and an antiparallel dimer of Cm-p5 with improved antifungal activity. Considering the alarming increase of microbial resistance to conventional antibiotics, here we evaluated the antimicrobial activity of these derivatives against multiresistant and problematic bacteria and against important viral agents. The three peptides showed a moderate activity against Pseudomonas aeruginosa, Klebsiella pneumoniae Extended Spectrum β-Lactamase (ESBL), and Streptococcus agalactiae, with MIC values > 100 µg/mL. They exerted a considerable activity with MIC values between 25–50 µg/mL against Acinetobacter baumanii and Enterococcus faecium. In addition, the two dimers showed a moderate activity against Pseudomonas aeruginosa PA14. The three Cm-p5 derivatives inhibited a virulent extracellular strain of Mycobacterium tuberculosis, in a dose-dependent manner. Moreover, they inhibited Herpes Simplex Virus 2 (HSV-2) infection in a concentration-dependent manner, but had no effect on infection by the Zika Virus (ZIKV) or pseudoparticles of Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2). At concentrations of >100 µg/mL, the three new Cm-p5 derivatives showed toxicity on different eukaryotic cells tested. Considering a certain cell toxicity but a potential interesting activity against the multiresistant strains of bacteria and HSV-2, our compounds require future structural optimization.

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Antimicrobial activity of human hepcidin 20 and 25 against clinically relevant bacterial strains: Effect of copper and acidic pH

Peptides ◽

10.1016/j.peptides.2010.08.007 ◽

2010 ◽

Vol 31 (11) ◽

pp. 1995-2002 ◽

Cited By ~ 55

Author(s):

Giuseppantonio Maisetta ◽

Raffaele Petruzzelli ◽

Franca Lisa Brancatisano ◽

Semih Esin ◽

Alberto Vitali ◽

...

Keyword(s):

Antimicrobial Activity ◽

Acidic Ph ◽

Bacterial Strains ◽

Effect Of Copper

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Comparative Study on the Antimicrobial Efficacy of Methanolic Extract of Root, Callus and Fruit Extracts of Myxopyrum smilacifolium Blume

International Journal of Applied Sciences and Biotechnology ◽

10.3126/ijasbt.v2i4.11362 ◽

2014 ◽

Vol 2 (4) ◽

pp. 521-524

Author(s):

RP Praveen ◽

Ashalantha Nair

Keyword(s):

Antimicrobial Activity ◽

Methanolic Extract ◽

Fungal Strain ◽

Antimicrobial Efficacy ◽

Bacterial Strains ◽

E Coli ◽

Root Extracts ◽

Fruit Extracts ◽

Root Callus ◽

And Staphylococcus Aureus

The aim of the present study was to compare the antimicrobial efficacy of methanolic extract of root, callus and fruit of Myxopyrum smilacifolium Blume. Antimicrobial activity was tested using agar well diffusion with four bacterial strains viz: Escherechia coli, Enterococcus faecalis, Bacillus subtilis and Staphylococcus aureus of which E. coli alone was gram negative. The fungal strain employed was Candida albicans. Root extracts shown to be effective only against B. subtilis. Fruit extracts showed the maximum antimicrobial activity against all the microbial species considered for the current study except against S. aureus. Highlight of the present study was the antimicrobial activity of callus extracts. DOI: http://dx.doi.org/10.3126/ijasbt.v2i4.11362 Int J Appl Sci Biotechnol, Vol. 2(4): 521-524

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