Antimicrobial silver inhibits bacterial movement and stalls flagellar motor

AbstractSilver (Ag) has been gaining broad attention due to their antimicrobial activities and the increasing resistance of bacteria to commonly prescribed antibiotics. However, various aspects of the antimicrobial mechanism of Ag have not been understood, including how silver affects the motility of bacteria, a factor that is intimately related to bacterial virulence. Here we report our study on the antibiotic effects of Ag+ ions on the motility of E. coli bacteria using swimming and tethering assays. We observed that the bacteria slowed down dramatically when subjected to Ag+ ions, providing direct evidence showing that Ag inhibits the motility of bacteria. In addition, through tethering assays, we monitored the rotation of flagellar motors and observed that the tumbling frequency of bacteria increased significantly in the presence of Ag+ ions. Furthermore, the rotation of bacteria in the tethering assays were analyzed using hidden Markov model (HMM); and we found that Ag+-treatment led to a significant decrease in the tumbling-to-running transition rate of the bacteria, suggesting that the rotation of bacterial flagellar motors was stalled by Ag+ ions. This work provided a new quantitative understanding on the mechanism of Ag-based antimicrobial agents in bacterial motility.

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DPPH-Scavenging and Antimicrobial Activities of Asteraceae Medicinal Plants on Uropathogenic Bacteria

Evidence-based Complementary and Alternative Medicine ◽

10.1155/2020/7807026 ◽

2020 ◽

Vol 2020 ◽

pp. 1-9 ◽

Cited By ~ 2

Author(s):

Phan-Canh Trinh ◽

Le-Thi-Thanh Thao ◽

Hoang-Tran-Viet Ha ◽

TuAnh Nguyen

Keyword(s):

Antimicrobial Agents ◽

Natural Antioxidants ◽

Ethyl Acetate Fraction ◽

Antimicrobial Activities ◽

Chrysanthemum Morifolium ◽

Bacterial Strains ◽

Ageratum Conyzoides ◽

Potent Effect ◽

E Coli ◽

Dpph Scavenging

Asteraceae species were widely applied in traditional medicines in Asian countries as sources of natural antioxidants and antimicrobial agents. This study aimed to evaluate DPPH-scavenging capacities and antimicrobial activities of nine Asteraceae species collected from Southern Vietnam. Antioxidant and antimicrobial activities were determined by standard protocols. Essential oils from Ageratum conyzoides, Helianthus annuus, and Artemisia vulgaris indicated significant inhibitory effects on Staphylococcus aureus and Candida spp. Crude extracts and fractions from Taraxacum officinale, Chrysanthemum morifolium, A. conyzoides, and Tagetes erecta showed inhibitory ability on at least one testing bacterial strains including S. aureus, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. In a study on clinical isolates, ethyl acetate fraction from A. conyzoides flower displayed the most potent effect on uropathogenic E. coli and K. pneumoniae with MIC at 1.25–10 mg/ml and 5–12.5 mg/ml, respectively. DPPH-scavenging assay indicated that T. erecta extract had the lowest IC50 (17.280 μg/ml) and is 2.4 times higher than vitamin C (7.321 μg/ml). This study revealed that A. conyzoides has good potential against uropathogenic E. coli and K. pneumoniae, and therefore could be applied for prophylactic treatment of urinary infection.

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Synthesis, Characterization, and Thermal and Antimicrobial Activities of Some Novel Organotin(IV): Purine Base Complexes

Journal of Chemistry ◽

10.1155/2013/568195 ◽

2013 ◽

Vol 2013 ◽

pp. 1-12 ◽

Cited By ~ 3

Author(s):

Reena Jain ◽

Rajeev Singh ◽

N. K. Kaushik

Keyword(s):

Antimicrobial Agents ◽

Rhizopus Oryzae ◽

Antimicrobial Activities ◽

Spectral Studies ◽

Purine Base ◽

Mass Spectral ◽

E Coli ◽

Kinetic And Thermodynamic Parameters ◽

C Nmr

A new series of organotin(IV) complexes with purine bases theophylline (HL1) and theobromine (L2) of the types R3Sn(L1), R2Sn(L1)Cl, R3Sn(L2)Cl, and R2Sn(L2)Cl2(R = C6H5CH2–;p-ClC6H4CH2–) have been synthesized in anhydrous THF. The complexes were characterized by elemental analysis, conductance measurements, molecular weight determinations, UV-vis, IR,1H,13C NMR, and mass spectral studies. Various kinetic and thermodynamic parameters of these complexes have also been determined using TG/DTA technique. The thermal decomposition techniques indicate the formation of SnO2as a residue. The results show that the ligands act as bidentate, forming a five-member chelate ring. All the complexes are 1 : 1 metal-ligand complexes. In order to assess their antimicrobial activity, the ligands and their corresponding complexes have also been testedin vitroagainst bacteria (E. coli, S. aureus, andP. pyocyanea) and fungi (Rhizopus oryzaeandAspergillus flavus). All the complexes exhibit remarkable activity, and the results provide evidence that the studied complexes might indeed be a potential source of antimicrobial agents.

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Synthesis of sulfonamides bearing 1,3,5-triarylpyrazoline and 4-thiazolidinone moieties as novel antimicrobial agents

Journal of the Serbian Chemical Society ◽

10.2298/jsc180621057t ◽

2020 ◽

Vol 85 (2) ◽

pp. 155-162

Author(s):

Thi-Dan Thach ◽

Thi Le ◽

Thien-Annguyen Nguyen ◽

Chi-Hien Dang ◽

Van-Su Dang ◽

...

Keyword(s):

Antimicrobial Agents ◽

Antimicrobial Activities ◽

Significant Inhibition ◽

Mercaptoacetic Acid ◽

Bacterial Strains ◽

Reference Drug ◽

E Coli ◽

Yeast Strains ◽

Microbial Strains

Two series of sulfonamides were synthesized from 4-hydrazinylbenzenesulfonamide as the key starting material. 1,3,5-Triarylpyrazoline sulfonamides (2a?i) were obtained by cyclocondensation of various chalcones in 53? ?64 % yields, while 4-thiazolidinone derivatives (4a?e) were synthesized by cyclocondensation between mercaptoacetic acid and different phenylhydrazones in 43?62 % yields. The synthesized compounds were characterized based on FTIR, 1H-NMR, 13C-NMR and HRMS data. The sulfonamides were evaluated for their in vitro antimicrobial activities against four bacterial strains (E. coli, P. aeruginosa, B. subtillis and S aureus), two filamentous fungal strains (A. niger and F. oxysporum) and two yeast strains (C. albicans and S. cerevisiae). Seven pyrazolines, 2a?c and 2e?h, exhibited significant inhibition of different microbial strains. Among them, compound 2b displayed good antifungal activity against A. niger (MIC value at 12.5 ?g mL-1) over the reference drug.

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Efficiency of Basil Essential Oil Antimicrobial Agents under Different Shading Treatments and Harvest Times

Agronomy ◽

10.3390/agronomy11081574 ◽

2021 ◽

Vol 11 (8) ◽

pp. 1574

Author(s):

Zoran S. Ilić ◽

Lidija Milenković ◽

Ljubomir Šunić ◽

Nadica Tmušić ◽

Jasna Mastilović ◽

...

Keyword(s):

Antimicrobial Activity ◽

Essential Oil ◽

Essential Oils ◽

Antimicrobial Agents ◽

Antimicrobial Activities ◽

Plant Production ◽

Exposure Control ◽

Harvest Time ◽

E Coli ◽

Growing Conditions

The aim of this study was to determine the antimicrobial activity of essential oils obtained from sweet basil (Ocimum basilicum L. cv. ‘Genovese’) cultivated in the open field under different shading conditions (red, blue, and pearl nets with a shade index of 50% and full sunlight exposure (control plants)), harvested at different times. The antimicrobial activity of basil essential oils (BEOs) obtained from all samples was determined for four microorganisms, while determinations for an additional five microorganisms included samples from non-shaded plants, plants grown under red and pearl nets, and second harvest of plants grown under blue net. Basil essential oil exhibited antimicrobial activity surpassing the activity of relevant commercial antibiotics regardless of growing conditions in the case of B. cereus, K. pneumoniae and C. albicans, while superior antimicrobial activity was exhibited in the case of essential oils from plants grown under blue nets in the case of S. aureus, E. coli and P. vulgaris. The influence of the application of colored shading nets was highly significant (p < 0.01) in the cases of all analyzed microorganisms except C. albicans and P. aeruginosa, while the influence of harvest time was proven in the cases of all microorganisms except K. pneumoniae. ANOVA proved that antimicrobial activities are highly dependent on the methods of plant production, shading treatment, and harvest time. Obtained results are discussed in relation to previously determined composition and yield of essential oils from basil grown under shade nets and harvested in different periods.

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Antimicrobial Activities of Cymbopogon citratus and Ximenia Americana Leaf Extracts Against Some Selected Bacterial and Yeast Clinical Isolates

Asian Journal of Biochemistry, Genetics and Molecular Biology ◽

10.9734/ajbgmb/2021/v9i130204 ◽

2021 ◽

pp. 1-10

Author(s):

A. U. Hassan ◽

A. H. Madu ◽

U. O. Ozojiofor ◽

A. H. Galadanci ◽

I. B. Mato ◽

...

Keyword(s):

Antimicrobial Agents ◽

Antimicrobial Activities ◽

Cymbopogon Citratus ◽

Leaf Extracts ◽

Phytochemical Content ◽

E Coli ◽

Plant Parts ◽

Ximenia Americana ◽

Bioassay Technique ◽

Emergence Of Resistance

Increasing emergence of resistance to antibiotics by pathogenic microorganisms worldwide necessitates the need for finding new antimicrobial agents with minimal resistance and side effects. This study was carried out to investigate the phytochemical content and antimicrobial activities of two ethno-medicinal plants namely: Cymbopogon citratus and Ximenia Americana. Methanol and aqueous were used as solvent for a soxhlet and aqueous percolation extraction techniques to obtain the crude extracts of the named plant parts. Tannins, steroids, reducing sugars, tritapenoids and Flavonoids were found present in these plant extracts. GC-MS analysis done in this study indicates the presence of some basic phenolic compounds, such as; Cyclohexane-1-3,5-trione & 2-phenyl-1,4-benzopyrone, in the C. citratus extract and methyl guanidine & 3-meyhylheptyl acetate in the X. americana extract, which have been attributed with numerous antimicrobial effects onmicrobial pathogens. Using an agar well diffusion bioassay technique the C. citratus extracts shows; both the extracts are active against E. coli and P. aeroginosa. While X. americana extracts shows a higher activity against C. albican. However the MIC/MBC/MFC of all the extracts shows that known of the extracts has an active viability below 12.5µg/ml.

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Synthesis and Biological Evaluation of 1,2,3-Triazole Tethered Thymol-1,3,4-Oxadiazole Derivatives as Anticancer and Antimicrobial Agents

Pharmaceuticals ◽

10.3390/ph14090866 ◽

2021 ◽

Vol 14 (9) ◽

pp. 866

Author(s):

Abdulraheem S. A. Almalki ◽

Syed Nazreen ◽

Azizah M. Malebari ◽

Nada M. Ali ◽

Ahmed A. Elhenawy ◽

...

Keyword(s):

Antimicrobial Agents ◽

Antimicrobial Activities ◽

Biological Evaluation ◽

Standard Drug ◽

E Coli ◽

Hct 116 ◽

Oxadiazole Derivatives ◽

Synthesis And Biological Evaluation ◽

Better Than ◽

Mcf 7

A library of 1,2,3-triazole-incorporated thymol-1,3,4-oxadiazole derivatives (6–18) hasbeen synthesized and tested for anticancer and antimicrobial activities. Compounds 7, 8, 9, 10, and 11 exhibited significant antiproliferative activity. Among these active derivatives, compound 2-(4-((5-((2-isopropyl-5-methylphenoxy)methyl)-1,3,4-oxadiazol-2-ylthio)methyl)-1H-1,2,3-triazol-1-yl)phenol (9) was the best compound against all three tested cell lines, MCF-7 (IC50 1.1 μM), HCT-116 (IC50 2.6 μM), and HepG2 (IC50 1.4 μM). Compound 9 was found to be better than the standard drugs, doxorubicin and 5-fluorouracil. These compounds showed anticancer activity through thymidylate synthase inhibition as they displayed significant TS inhibitory activity with IC50 in the range 1.95–4.24 μM, whereas the standard drug, Pemetrexed, showed IC50 7.26 μM. The antimicrobial results showed that some of the compounds (6, 7, 9, 16, and 17) exhibited good inhibition on Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The molecular docking and simulation studies supported the anticancer and antimicrobial data. It can be concluded that the synthesized 1,2,3-triazole tethered thymol-1,3,4-oxadiazole conjugates have both antiproliferative and antimicrobial potential.

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DPPH-scavenging and antimicrobial activities of Asteraceae medicinal plants on uropathogenic bacteria

10.1101/2019.12.25.888404 ◽

2019 ◽

Author(s):

Trinh Canh Phan ◽

Thao Thi Thanh Le ◽

Ha Tran Viet Hoang ◽

TuAnh Nguyen

Keyword(s):

Antimicrobial Agents ◽

Ethyl Acetate Fraction ◽

Antimicrobial Activities ◽

Chrysanthemum Morifolium ◽

Tagetes Erecta ◽

Bacterial Strains ◽

Ageratum Conyzoides ◽

Potent Effect ◽

E Coli ◽

Dpph Scavenging

AbstractAsteraceae species were widely applied in traditional medicines in Asia countries as sources of natural antioxidants and antimicrobial agents. This study aimed to evaluate DPPH-scavenging capacities and antimicrobial activities of nine Asteraceae species collected from Southern Vietnam. Antioxidant and antimicrobial activities were determined by standard protocols. Essential oils from Ageratum conyzoides, Helianthus annuus, Artemisia vulgaris indicated significant inhibitory effects on Staphyloccocus aureus and Candida spp.. Crude extracts and fractions from Taraxacum officinale, Chrysanthemum morifolium, Ageratum conyzoides, Tagetes erecta showed inhibitory ability on at least one testing bacterial strains including S. aureus, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa. Study on clinical isolates, ethyl acetate fraction from A. conyzoides displayed the most potent effect on uropathogenic E. coli and K. pneumoniae with MIC at 1.25-10 mg/ml and 5-12.5 mg/ml, respectively. DPPH scavenging assay indicated that Tagetes erecta extract had the lowest IC50 (17.280 μg/ml) and 2.5 times higher than vitamin C (7.321 μg/ml). This study revealed that A. conyzoides has good potential against uropathogenic E. coli and K. pneumoniae, and could, therefore, apply to prophylactic urinary tract infection.

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Phytochemical Compositions and Antimicrobial Activities of Citrus sinensis and Citrus aurantifolia Peels on Selected Pathogenic Bacteria Isolated from Jollof Rice

International Journal of Pathogen Research ◽

10.9734/ijpr/2019/v2i330075 ◽

2019 ◽

pp. 1-7

Author(s):

Mojisola Abiola Asowata-Ayodele ◽

Peter Anani Dabesor ◽

Bolaji Afolabi

Keyword(s):

Pathogenic Bacteria ◽

Antimicrobial Agents ◽

Orange Peel ◽

Antimicrobial Activities ◽

Diffusion Method ◽

Phytochemical Analysis ◽

Zone Of Inhibition ◽

E Coli ◽

Orange Peels ◽

Peel Extract

Aims: The aim of this study is to investigate the antimicrobial activities of aqueous and ethanolic (EtOH) extracts of orange (C. sinensis Pers.) and lime (C.aurantifolia (Christm.) Swingle) peels on some selected pathogenic bacteria isolated from jollof rice. Study Design: Antimicrobial analysis, phytochemical analysis Place and Duration of Study: Microbiology Laboratory, Department of Biological Sciences, Wesley University Ondo, Ondo State, Nigeria, between June and July 2017. Methodology: Antimicrobial analysis of aqueous and EtOH extracts prepared from orange and lime peels were done by using the agar well diffusion method against the selected pathogenic bacteria. The extracts were screened for anti-nutrients such as alkaloids, tannins, oxalate, phytate and glycosides. Results: The EtOH extracts of orange peel showed a remarkable zone of inhibition against Escherichia coli (23.5 ± 0.1 mm) followed by Staphylococcus aureus (11.4 ± 0.0 mm) and Bacillus cereus (9.8 ± 0.0 mm). Whereas, the aqueous extracts of orange showed no zone of inhibition against the tested pathogenic bacteria. In addition the EtOH peel extract of lime showed maximum zone of inhibition against S. aureus (15.5 ± 0.0 mm) followed by E. coli (14.3 ± 0.1 mm) and B. cereus (12.1 ± 0.2 mm), whereas its aqueous peel extract showed no zone of inhibition against K. pneumonia, S. aureus, E. coli and B. cereus. Both EtOH extracts of orange and lime peels showed no zone of inhibition against K. pneumonia. Streptomycin, the reference antibiotic, had no zone of inhibition against B. cereus and S. aureus whereas it recorded maximum zone of inhibition against E. coli (24.0 ± 0.0 mm) and K. pneumonia (25.1 ± 0.1 mm). The phytochemical analysis showed presence of oxalate, alkaloids, phytate, tannins and glycoside in the aqueous and EtOH extracts of lime and orange peels. The antimicrobial activities of EtOH extracts of both lime and orange peels demonstrated inhibitory effect against the targeted organisms such as B. cereus, S. aureus and E. coli. Conclusion: The exploration of novel antimicrobial agents from natural resources such as plant like Lime and sweet orange as food preservative is due to the presence of various secondary metabolites.

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Copper(II) mixed-ligand complexes containing 1, 10-phenanthroline, adenine and thymine: Synthesis, characterization and antibacterial activities

10.31221/osf.io/d95yt ◽

2019 ◽

Author(s):

Chem Int

Keyword(s):

Copper Complexes ◽

Antimicrobial Agents ◽

Conductivity Measurement ◽

Antibacterial Activities ◽

Antimicrobial Activities ◽

Bacterial Strains ◽

E Coli ◽

In Vivo Cytotoxicity

New copper complexes, [Cu(phen)2(Thy)]2Cl and [Cu(phen)2(Ad)]2Cl (phen = 1,10-phenantroline, Ad (Adenine, a purine nucleobase) and Thy (Thymine, a pyrimidine nucleobase)), were synthesized and characterized by atomic absorption spectroscopy (AAS), conductivity measurement, UV-visible and infrared (IR) techniques. The complexes were tested for their antimicrobial activity against two gram positive and two gram negative bacterial strains. The results of in vitro antimicrobial activities were compared with the commercially available antimicrobial agents (ciprofloxacin and chloramphenicol). This comparative study has demonstrated that [Cu(phen)2(Thy)]2Cl inhibited the growth of methicillin resistant Staphylococcus aureous (MRSA), Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumonia) better than chloramphenicol by 11.25%, 19.41% and 25.35%, respectively. It also showed better activities than ciprofloxacine on MRSA and K. pneumoniae by 2.50% and 12.13%, respectively. Similarly, [Cu(phen)2(Ad)]2Cl demonstrated better inhibitions than chloramphenicol against MRSA, E. coli and K. pneumoniae by 11.24%, 2.48% and 9.06%, respectively. Therefore, after in vivo cytotoxicity investigations, these complexes could be considered as potential antimicrobial agents.

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Synthesis, Characterization and Antimicrobial Activities of 1,4- Disubstituted 1,2,3-Triazole Compounds

Current Topics in Medicinal Chemistry ◽

10.2174/1568026620666200819143029 ◽

2020 ◽

Vol 20 (25) ◽

pp. 2289-2299

Author(s):

Seck Insa ◽

Fall Alioune ◽

Ba Lalla Aicha ◽

Ndoye Samba Fama ◽

Ka Seydou ◽

...

Keyword(s):

Broad Spectrum ◽

Antimicrobial Agents ◽

Biological Activities ◽

Antimicrobial Activities ◽

Ambient Conditions ◽

Lead Structure ◽

E Coli ◽

Drug Molecules ◽

The World ◽

Microbial Strains

Background: 1,2,3-triazoles are five-membered heterocyclic scaffold; their broad-spectrum biological activities are known. Researchers around the world are increasingly being interested in this emerging area, owing to its immense pharmacological scope. Objective: This work summarizes the synthesis of 1,2,3-triazoles and the significance of this pattern as a lead structure for new drug molecules discovery. Methods: 1,2,3-triazoles can be obtained on a multigram scale through “click chemistry” under ambient conditions. Results: Sixteen compounds were synthesized and evaluated on five microbial strains E. coli, E. faecalis, P. aeruginosa, S. aureus and C. albicans. NMR, MS and IR were used to characterize all compounds. They were evaluated with their Minimum Inhibitory Concentrations (MICs) and interesting results were obtained with compounds 12a, 12b, 3, 2a and 2c, with MIC 0.14 μM (P. aeruginosa), 1.08 μM (E. coli), 1.20 μM (E. faecalis and C. albicans), 3.5 μM (E. faecalis) and 4.24 μM (C. albicans), respectively. P. aeruginosa and C. albicans were the most sensitive among all the strains. Conclusion: The synthesized compounds were found as potential antimicrobial agents against Gram (+), Gram (-) strains and fungi.

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