scholarly journals Evaluation of Ruthenium(II) N-Heterocyclic Carbene Complexes as Antibacterial Agents and Inhibitors of Bacterial Thioredoxin Reductase

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4282
Author(s):  
Hilke Burmeister ◽  
Pascal Dietze ◽  
Lutz Preu ◽  
Julia E. Bandow ◽  
Ingo Ott
Keyword(s):  
General Type ◽  
Antibacterial Agents ◽  
Thioredoxin Reductase ◽  
Gram Negative Bacteria ◽  
Antibacterial Effects ◽  
Carbene Complexes ◽  
Metal Free ◽  
Gram Positive Bacteria ◽  
Bacterial Growth Inhibition ◽  
And Staphylococcus Aureus

A series of ruthenium(II) complexes with N-heterocyclic carbene (NHC) ligands of the general type (arene)(NHC)Ru(II)X2 (where X = halide) was prepared, characterized, and evaluated as antibacterial agents in comparison to the respective metal free benzimidazolium cations. The ruthenium(II) NHC complexes generally triggered stronger bacterial growth inhibition than the metal free benzimidazolium cations. The effects were much stronger against Gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus) than against Gram-negative bacteria (Escherichia coli, Acinetobacter baumannii, Pseudomonas aeruginosa), and all complexes were inactive against the fungus Candida albicans. Moderate inhibition of bacterial thioredoxin reductase was confirmed for selected complexes, indicating that inhibition of this enzyme might be a contributing factor to the antibacterial effects.

scholarly journals N-Doped Carbon Quantum Dots as Fluorescent Bioimaging Agents

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 789
Author(s):  
Shih-Fu Ou ◽  
Ya-Yun Zheng ◽  
Sin-Jen Lee ◽  
Shyi-Tien Chen ◽  
Chien-Hui Wu ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Carbon Nanomaterials ◽  
Graphene Quantum Dots ◽  
Carbon Quantum Dots ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Fluorescence Characteristics ◽  
And Staphylococcus Aureus

Graphene quantum dots, carbon nanomaterials with excellent fluorescence characteristics, are advantageous for use in biological systems owing to their small size, non-toxicity, and biocompatibility. We used the hydrothermal method to prepare functional N-doped carbon quantum dots (N-CQDs) from 1,3,6-trinitropyrene and analyzed their ability to fluorescently stain various bacteria. Our results showed that N-CQDs stain the cell septa and membrane of the Gram-negative bacteria Escherichia coli, Salmonellaenteritidis, and Vibrio parahaemolyticus and the Gram-positive bacteria Bacillus subtilis, Listeria monocytogenes, and Staphylococcus aureus. The optimal concentration of N-CQDs was approximately 500 ppm for Gram-negative bacteria and 1000 ppm for Gram-positive bacteria, and the exposure times varied with bacteria. N-Doped carbon quantum dots have better light stability and higher photobleaching resistance than the commercially available FM4-64. When excited at two different wavelengths, N-CQDs can emit light of both red and green wavelengths, making them ideal for bioimaging. They can also specifically stain Gram-positive and Gram-negative bacterial cell membranes. We developed an inexpensive, relatively easy, and bio-friendly method to synthesize an N-CQD composite. Additionally, they can serve as a universal bacterial membrane-staining dye, with better photobleaching resistance than commercial dyes.

scholarly journals Expression of Penaeidins 3a in Transgenic Duckweed Confers Antibacterial Ability

2021 ◽  
Author(s):  
Lin Yang ◽  
Jinge Sun ◽  
Qiuting Ren ◽  
Xu Ma ◽  
Yaya Wang ◽  
...  
Keyword(s):  
Metabolic Pathways ◽  
Quantitative Proteomics ◽  
Metabolic Process ◽  
Sphingolipid Metabolism ◽  
35S Promoter ◽  
Gram Negative Bacteria ◽  
Protein Enrichment ◽  
Urgent Problem ◽  
Gram Positive Bacteria ◽  
And Staphylococcus Aureus

Abstract Background With the development of aquaculture, fish and shrimp diseases have been paid more and more attention in the world. How to improve the immunity of aquatic animals was an urgent problem to be solved. Duckweed (Lemnacecae), as a eukaryote, could be an ideal feedstock for the production of antimicrobial peptides. Result Penaeidins 3a (Pen 3a) from Litopenaeus vannamei was expressed under the control of CaMV-35S promoter in duckweed, Lemna turionifera 5511. Bacteriostatic test by Pen3a duckweed extract showed the antibacterial activity against Escherichia coli and Staphylococcus aureus. Transcriptome analysis of WT and Pen3a duckweed showed different results, and the protein metabolic process was the most up-regulated DEGs. In Pen 3a transgenic duckweed, the expression of sphingolipid metabolism and phagocytosis process-related genes have been significantly up-regulated. Quantitative proteomics suggested a remarkable difference in protein enrichment in metabolic pathways. Conclusion Our study provide a novel solution on aquaculture and water purification. The Pen 3a transgenic duckweed extraction inhibit the growth of gram-negative bacteria, gram-positive bacteria, which could be applied to control the bacteria in lake. The results could lay the foundation for the subsequent production of antibiotics.

Inhibition of Aspergillus flavus and Selected Gram-positive Bacteria by Chelation of Essential Metal Cations by Polyphosphates

1991 ◽  
Vol 54 (5) ◽  
pp. 360-365 ◽  
Author(s):  
S.J. KNABEL ◽  
H.W. WALKER ◽  
P.A. HARTMAN
Keyword(s):  
Aspergillus Flavus ◽  
Binding Sites ◽  
Iron Supplementation ◽  
Cation Binding ◽  
Gram Negative Bacteria ◽  
Positive Bacterium ◽  
Gram Positive ◽  
Tetrasodium Pyrophosphate ◽  
Gram Positive Bacteria ◽  
And Staphylococcus Aureus

A simple well-plate technique was utilized to determine the effect of various metals on the growth of microorganisms in media containing different polyphosphates. Aspergillus flavus and four gram-positive bacteria were completely inhibited by media containing 1% of various alkaline polyphosphates, whereas four gram-negative bacteria were not. Significant differences were observed between the type of polyphosphate added, the type of metal added, and the species of gram-positive bacterium inhibited. The addition of Mg2+ stimulated growth of A. flavus and Bacillus cereus in the presence of tetrasodium pyrophosphate, whereas Mn2+ permitted growth of A. flavus and Staphylococcus aureus in the presence of sodium hexametaphosphate. Iron supplementation allowed the growth of S. aureus and Listeria monocytogenes on media containing 1 % tetrasodium pyrophosphate. A method for determining the amount of calcium and magnesium in water was modified to detect free Mg2+ by replacing EDTA with phosphate. The addition of free Mg2+, but not Mg2+ chelated by tetrasodium pyrophosphate, permitted the growth of B. cereus on a medium containing tetrasodium pyrophosphate. It is speculated that polyphosphates specifically inhibited A. flavus and gram-positive bacteria by removing essential metals from cation-binding sites located within their cell walls.

scholarly journals Synthesis and Evaluation of Novel Fluorinated 2-Styrylchromones as Antibacterial Agents

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Mehbub Momin ◽  
Deresh Ramjugernath ◽  
Hafizah Chenia ◽  
Neil A. Koorbanally
Keyword(s):  
Antibacterial Activity ◽  
Phenyl Ring ◽  
Antibacterial Agents ◽  
Klebsiella Pneumonia ◽  
Gram Negative Bacteria ◽  
Fluorine Substitution ◽  
Single Strain ◽  
E Coli ◽  
Gram Positive Bacteria ◽  
Activity Indices

A range of fluorinated 2-styrylchromones (5a–g) of which six were new (5a–f) were prepared in three steps using the Baker-Venkataraman rearrangement along with two methoxylated derivatives (5h-i) and a methylenedioxy derivative (5j) and screened for their antibacterial activity using Gram-positive bacteria (Staphylococcus aureus, sciuri, andxylosusas well asBacillus subtilis) and Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, andKlebsiella pneumonia). The compounds were most effective againstB. subtilisfollowed byS. aureusand a single strain ofE. coli(ATCC 25922). Difluorination on the phenyl ring was shown to enhance antibacterial activity, and fluorine substitution at the 6 position was shown to be far superior to substitution at the 7 position. In comparison to tetracycline, the activity indices of the fluorinated styrylchromones ranged from 0.50 to 0.75 againstB. subtilis. The crystal structure of 2′-fluoro-2-styrylchromone is also presented, and the molecule was shown to be planar.

scholarly journals Densely Functionalized 2-methylideneazetidines: Evaluation as Antibacterials

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3891
Author(s):  
Giovanni Petrillo ◽  
Cinzia Tavani ◽  
Lara Bianchi ◽  
Alice Benzi ◽  
Maria Maddalena Cavalluzzi ◽  
...  
Keyword(s):  
Antibacterial Agents ◽  
Inhibitory Concentration ◽  
General Procedure ◽  
Eukaryotic Cells ◽  
Gram Negative Bacteria ◽  
Pharmacological Profile ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Structure Activity

Twenty-two novel, variously substituted nitroazetidines were designed as both sulfonamide and urethane vinylogs possibly endowed with antimicrobial activity. The compounds under study were obtained following a general procedure recently developed, starting from 4-nitropentadienoates deriving from a common β-nitrothiophenic precursor. While being devoid of any activity against fungi and Gram-negative bacteria, most of the title compounds performed as potent antibacterial agents on Gram-positive bacteria (E. faecalis and three strains of S. aureus), with the most potent congener being the 1-(4-chlorobenzyl)-3-nitro-4-(p-tolyl)azetidine 22, which displayed potency close to that of norfloxacin, the reference antibiotic (minimum inhibitory concentration values 4 and 1–2 μg/mL, respectively). Since 22 combines a relatively efficient activity against Gram-positive bacteria and a cytotoxicity on eucharyotic cells only at 4-times higher concentrations (inhibiting concentration on 50% of the cultured eukaryotic cells: 36 ± 10 μM, MIC: 8.6 μM), it may be considered as a promising hit compound for the development of a new series of antibacterials selectively active on Gram-positive pathogens. The relatively concise synthetic route described herein, based on widely available starting materials, could feed further structure–activity relationship studies, thus allowing for the fine investigation and optimization of the toxico-pharmacological profile.

scholarly journals Synthesis of Some Derivatives of 4-phenyl-1,3-dihydro-2H-imidazole-2-thion Using Ionic Liquid as Catalyst and Evaluation of Their Antimicrobial Activity

2017 ◽  
Vol 9 (2) ◽  
pp. 45 ◽  
Author(s):  
Bahareh Behmaram ◽  
Naser Foroughifar ◽  
Neda Foroughifar ◽  
Sara Hallajian
Keyword(s):  
Escherichia Coli ◽  
Antibacterial Activity ◽  
Ionic Liquid ◽  
13C Nmr Spectroscopy ◽  
Basic Medium ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Derivatives Of ◽  
And Staphylococcus Aureus

The synthesis of some 1,3-diazoles and thiazoles was realized in different conditions:a) In the presence of PTSA or sulfuric acid as catalyst we obtained only diazole products(4a-d).b) In basic medium such as DABCO or sodium hydroxide and ionic liquid afforded thiazoles.c) Both products, diazoles and thiazoles were collected when using methanol as catalyst and solvent.All structures were confirmed by IR, 1H NMR and 13C NMR spectroscopy. The antibacterial activity of some synthesized compounds was investigated against Escherichia Coli (ATCC: 25922) and Serratia marcescens (ATCC: 13880) as gram negative bacteria, Bacillus sabtilis (ATCC: 6633) and Staphylococcus aureus (ATCC: 6338) as gram positive bacteria. Some of these products exhibit good activities to significant antibacterial activity.

Three New Abietane-Type Diterpenoids from Plectranthus africanus and Their Antibacterial Activities

Planta Medica ◽  
2017 ◽  
Vol 84 (01) ◽  
pp. 59-64 ◽  
Author(s):  
Raïssa Nzogong ◽  
Blaise Nganou ◽  
Alex Tedonkeu ◽  
Maurice Awouafack ◽  
Mathieu Tene ◽  
...  
Keyword(s):  
Minimal Inhibitory Concentration ◽  
Inhibitory Concentration ◽  
Methanol Extract ◽  
2D Nmr ◽  
Antibacterial Activities ◽  
Gram Negative Bacteria ◽  
Gram Positive Bacteria ◽  
Whole Plant ◽  
New Compounds ◽  
And Staphylococcus Aureus

AbstractThree new abietane-type diterpenoids, plectranthroyleanones A – C (1 – 3), together with five known compounds (4 – 8) were isolated from the methanol extract of the whole plant of Plectranthus africanus using column chromatography techniques. The structures of the new compounds were elucidated using a combination of 1D and 2D NMR and HRESIMS analyses. Compound 1 exhibited weak activities with minimal inhibitory concentration values of 75 µg/mL against gram-positive bacteria, Bacillus subtilis and Staphylococcus aureus, and 150 µg/mL against two gram-negative bacteria, Pseudomonas aeruginosa and Klebsiella pneumoniae, respectively, while 2 and 3 had moderate antibacterial activity against K. pneumoniae with a minimal inhibitory concentration value of 37.5 µg/mL.

scholarly journals Synthesis and Characterization of Some New Pyrazoline and Isoxazoline Derivatives as Antibacterial Agents

2016 ◽  
Vol 13 (3) ◽  
pp. 568-577
Author(s):  
Baghdad Science Journal
Keyword(s):  
Sodium Hydroxide ◽  
Antibacterial Agents ◽  
Amine Hydrochloride ◽  
Gram Negative Bacteria ◽  
Gram Positive Bacteria ◽  
In Vitro Antibacterial Activity ◽  
Derivatives Of ◽  
Number Of Bacteria

In this paper some chalcones (C1-C8) are prepared based on the reaction of one mole of substituted acetophenone with one mole of substituted benzaldehydes in the presence of (40%) sodium hydroxide as a base. Pyrazolines (P1–P8) are prepared from the reaction of chalcones (C1-C8) with hydrazine hydrate. Isoxazoline (I1-I8) is prepared from the reaction of chalcones (C1-C8) with hydroxyl amine hydrochloride in the presence of (10%) sodium hydroxide as a base. These compounds are characterized by using various physical and spectral methods. The compounds are screened for their in vitro antibacterial activity using gram-positive bacteria and gram-negative bacteria. Several derivatives of pyrazolines and isoxazolines are produced well to moderate activities against number of bacteria.

ANTIBACTERIAL ACTIVITY OF BARK EXTRACTS OF FICUS GLOMERATA ROXB AGAINST SOME GRAM POSITIVE AND GRAM NEGATIVE BACTERIA

INDIAN DRUGS ◽  
2013 ◽  
Vol 50 (05) ◽  
pp. 44-47
Author(s):  
S. D. Bhinge ◽  
◽  
M. G Hogade ◽  
A. S Savali ◽  
H. R. Chitapurkar ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Diffusion Method ◽  
Gram Negative Bacteria ◽  
Aqueous Extracts ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Agar Diffusion Method ◽  
Ficus Glomerata ◽  
And Staphylococcus Aureus

Petroleum ether, ethanol and aqueous extracts of the bark of Ficus glomerata (Urticaceae) were screened for their antibacterial activity using agar diffusion method. They were tested against six bacteria; three Gram-positive bacteria (Bacillus subtilis, Bacillus aureus and Staphylococcus aureus) and three Gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa). The susceptibility of the microorganisms to the extracts of these plants was compared with each other and with selected antibiotics.

Synthesis, Characterization and Antibacterial Activity of New Derivatives of Imidazolidine having Sulfamethoxazole Moiety

2019 ◽  
pp. 217-238 ◽  
Keyword(s):  
Antibacterial Activity ◽  
Schiff Bases ◽  
Diffusion Method ◽  
Gram Negative Bacteria ◽  
Acinetobacter Species ◽  
Gram Positive Bacteria ◽  
Ft Ir ◽  
Preliminary Study ◽  
Derivatives Of ◽  
And Staphylococcus Aureus

This work includes Synthesis of new series of sulfa drugs derived from sulfamethoxazole containing substituted Imidazolidine moiety. These compounds expected to have antibacterial activity, due to their Imidazolidine moiety This work includes synthesis of some new Schiff bases (II1-5) by condensation of sulfamethoxazole drug(I) with some aldehydes (1-5) (benzaldehyde, p-chloro benzaldehyde, p-nitro benzaldehyde, p-hyroxy benzaldehyde and p-N, N-dimethyl amino benzaldehyde). These Schiff bases were found to react with glycine, to prepared new imidazolidine derivatives (III1-5). The prepared compounds were characterized by physical properties, FT-IR and of the 1H-NMR spectroscopy. The preliminary study of antibacterial activity of final compounds has considered by well diffusion method. The tested compounds displayed effect against gram negative bacteria:( Acinetobacter species and Pseudomonas aeruginosa) and gram-positive bacteria (Streptococcus pyougenes and Staphylococcus aureus bacteria), which compared to DMSO as control, and good activity compared to sulfamethoxazole as standard.

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