scholarly journals Bioactivity of Isostructural Hydrogen Bonding Frameworks Built from Pipemidic Acid Metal Complexes

Molecules ◽  
2020 ◽  
Vol 25 (10) ◽  
pp. 2374
Author(s):  
Paula C. Alves ◽  
Patrícia Rijo ◽  
Catarina Bravo ◽  
Alexandra M. M. Antunes ◽  
Vânia André
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Activity ◽  
Drug Resistance ◽  
Antibacterial Activity ◽  
Hydrogen Bonding ◽  
Three Dimensional ◽  
Artemia Salina ◽  
Gram Negative Bacteria ◽  
Pipemidic Acid ◽  
Gram Negative

We report herein three novel complexes whose design was based on the approach that consists of combining commercially available antibiotics with metals to attain different physicochemical properties and promote antimicrobial activity. Thus, new isostructural three-dimensional (3D) hydrogen bonding frameworks of pipemidic acid with manganese (II), zinc (II) and calcium (II) have been synthesised by mechanochemistry and are stable under shelf conditions. Notably, the antimicrobial activity of the compounds is maintained or even increased; in particular, the activity of the complexes is augmented against Escherichia coli, a representative of Gram-negative bacteria that have emerged as a major concern in drug resistance. Moreover, the synthesised compounds display similar general toxicity (Artemia salina model) levels to the original antibiotic, pipemidic acid. The increased antibacterial activity of the synthesised compounds, together with their appropriate toxicity levels, are promising outcomes.

scholarly journals SYNTHESIS, CHARACTERIZATION AND ANTIMICROBIAL STUDIES ON CERTAIN SUBSTITUTED ARYLAZO IMIDAZOLE CONTAINING OXADIAZOLES

2012 ◽  
Vol 20 (20) ◽  
pp. 11-24
Author(s):  
Sreedevi MEESRAGANDA ◽  
Raghavendra Gum Prasad ALURU ◽  
Spoorthy Yadan NARASIMBA ◽  
Ravindnmath Laxmana Rao Krishna RAO
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Antibacterial Activity ◽  
Dilution Method ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Antimicrobial Studies ◽  
Serial Dilution Method

A series of novel substituted l-[5-(2-methyl-5-nitro-4phenyl-imidazol-lyl methyl)-2-phenyl-(1,3,4)oxadiazol-3-yl]-ethanones have been synthesized. Formation of 1,3,4-oxadiazole ring was accomplished by the reaction of the corresponding hydrazide with acetic anhydride. The structure determination of these compounds has been made on the basis of IR, 1H NMR, and elemental analysis. All the compounds were screened for their antibacterial activity. The antimicrobial activity of title compounds were examined against two gram-negative (Staphylococcus aureus and Bacillus subtilis), two gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa), and antifungal activity was carried out against Candida albicans. The MIC values for the newly synthesized compounds have been assessed by serial dilution method All the compounds demonstrated potent antibacterial activity.

scholarly journals Antimicrobial Activity of Undecan-x-Ones (x = 2-4)

2010 ◽  
Vol 59 (4) ◽  
pp. 301-306 ◽  
Author(s):  
ALINA KUNICKA-STYCZYŃSKA ◽  
JULIA GIBKA
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Activity ◽  
Antibacterial Activity ◽  
Population Viability ◽  
Gram Negative Bacteria ◽  
Disc Diffusion ◽  
Gram Negative ◽  
Fungistatic Activity ◽  
Agar Disc ◽  
Microbial Strains

As a continuation of our research on the biological activity of undecan-x-ones (x = 2-4), their antimicrobial activity towards bacteria Escherichia coli and Bacillus subtilis, yeast Candida mycoderma and mould Aspergillus niger, was investigated. The population viability of the tested microbial strains in the presence of undecan-x-ones was determined by the impedimetric and agar disc diffusion methods. Undecan-x-ones showed low antibacterial activity towards both Gram-positive and Gram-negative bacteria. Undecan-2-one and undecan-3-one exhibited high activity towards C. mycoderma. All undecan-x-ones expressed the strongest effect on A. niger. The tests have proven that due to high fungistatic activity undecan-x-ones can be used to aid stabilization of food and cosmetic matrices.

scholarly journals Proteomic response of Escherichia coli to a membrane lytic and iron chelating truncated Amaranthus tricolor defensin

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Tessa B. Moyer ◽  
Ashleigh L. Purvis ◽  
Andrew J. Wommack ◽  
Leslie M. Hicks
Keyword(s):  
Escherichia Coli ◽  
Antibacterial Activity ◽  
Antimicrobial Peptides ◽  
Mechanism Of Action ◽  
Gram Negative Bacteria ◽  
Amaranthus Tricolor ◽  
Core Motif ◽  
Gram Negative ◽  
E Coli ◽  
Membrane Lysis

Abstract Background Plant defensins are a broadly distributed family of antimicrobial peptides which have been primarily studied for agriculturally relevant antifungal activity. Recent studies have probed defensins against Gram-negative bacteria revealing evidence for multiple mechanisms of action including membrane lysis and ribosomal inhibition. Herein, a truncated synthetic analog containing the γ-core motif of Amaranthus tricolor DEF2 (Atr-DEF2) reveals Gram-negative antibacterial activity and its mechanism of action is probed via proteomics, outer membrane permeability studies, and iron reduction/chelation assays. Results Atr-DEF2(G39-C54) demonstrated activity against two Gram-negative human bacterial pathogens, Escherichia coli and Klebsiella pneumoniae. Quantitative proteomics revealed changes in the E. coli proteome in response to treatment of sub-lethal concentrations of the truncated defensin, including bacterial outer membrane (OM) and iron acquisition/processing related proteins. Modification of OM charge is a common response of Gram-negative bacteria to membrane lytic antimicrobial peptides (AMPs) to reduce electrostatic interactions, and this mechanism of action was confirmed for Atr-DEF2(G39-C54) via an N-phenylnaphthalen-1-amine uptake assay. Additionally, in vitro assays confirmed the capacity of Atr-DEF2(G39-C54) to reduce Fe3+ and chelate Fe2+ at cell culture relevant concentrations, thus limiting the availability of essential enzymatic cofactors. Conclusions This study highlights the utility of plant defensin γ-core motif synthetic analogs for characterization of novel defensin activity. Proteomic changes in E. coli after treatment with Atr-DEF2(G39-C54) supported the hypothesis that membrane lysis is an important component of γ-core motif mediated antibacterial activity but also emphasized that other properties, such as metal sequestration, may contribute to a multifaceted mechanism of action.

Morpholine- and Thiomorpholine-Based Amidodithiophosphonato Nickel Complexes: Synthesis, Characterization, P–N Cleavage, Antibacterial Activity and Silica Nano-Dispersion

2021 ◽  
Vol 21 (5) ◽  
pp. 2879-2891
Author(s):  
Enrico Podda ◽  
M. Carla Aragoni ◽  
Massimiliano Arca ◽  
Giulia Atzeni ◽  
Simon J. Coles ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Antibacterial Activity ◽  
Nickel Complex ◽  
Nickel Complexes ◽  
Silica Matrix ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Ft Ir ◽  
Hydrolysis Of

The reactivity of thiomorpholinium P-(4-methoxyphenyl)-N-thiomorpholin-amidodithiophosphonate (S-MorH+2)(S-Mor-adtp−) and morpholinium P-(4-methoxyphenyl)-N-morpholin-amidodithiophosphonate (O-MorH+2)(O-Mor-adtp−) towards nickel (II) dichloride hexahydrated is presented and the hydrolysis of the relevant metal complexes investigated. The hydrolytic products (S-MorH+2)2 [Ni(dtp)2]2− and (O-MorH+2)2[Ni(dtp)2]2− were characterized by means of FT-IR, 1H, and 31P NMR and XRD and the experimented P–N cleavage investigated and elucidated by means of DFT calculations. The antimicrobial activity of the neutral nickel complex [Ni(S-Mor-adtp)2] was tested against a set of Gram-positive and Gram-negative bacteria alongside with its nanodispersion in a silica matrix. The complex [Ni(S-Mor-adtp)2] did not show antibacterial activity, whilst the nano-dispersed sample [Ni(S-Mor-adtp)2]_SiO2 demonstrated inhibition to growth of Staphylococcus aureus. The nanocomposites were fully characterized by means of XRPD, TGA, SEM and dinitrogen sorption techniques.

Synthesis of new azobenzene dyes clubbed with thiazolidinone moiety and their applications

2020 ◽  
Vol 49 (3) ◽  
pp. 207-214 ◽  
Author(s):  
Hatem E. Gaffer ◽  
Ismail I. Althagafi
Keyword(s):  
Antimicrobial Activity ◽  
Antibacterial Activity ◽  
Proton Nuclear Magnetic Resonance ◽  
Spectral Studies ◽  
Gram Negative Bacteria ◽  
Anticancer Activities ◽  
Gram Positive ◽  
Gram Negative ◽  
Polyester Fabrics ◽  
Content Type

Purpose The purpose of this paper is to synthesize some new azobenzene dyestuffs clubbed with thiazolidinone moiety and their solicitation in dyeing polyester fabrics representing their antibacterial evaluation. Design/methodology/approach Herein, the authors report the synthesis of new thiazolidinone moiety after the coupling of diazotized 4-aminoacetophenone with resorcinol. The newly synthesized dyes were characterized by IR, elemental analysis, mass spectroscopy and proton nuclear magnetic resonance (1H NMR) spectral studies. The characteristics of dyeing of these dyestuffs were evaluated at optimum conditions. Concurrent with dyeing of polyester fabric for synthesized dyes with their antibacterial activity was estimated. Antimicrobial activity of the dyed fabrics at different concentrations was evaluated against gram-positive and gram-negative bacteria. Findings Synthesized azobenzene dyestuffs clubbed with thiazolidinone dyes were applied on polyester fabrics. It was remarked that the modified dyes exhibited better colourfastness properties. Furthermore, the synthesized dyes revealed antimicrobial activity against gram-positive and gram-negative bacteria. Research limitations/implications The synthesized azobenzene dyes for polyester dyeing were not bore earlier. Practical implications The azobenzene dyes were accountable for giving improved colourfastness properties on polyester fabrics. Social implications The synthesized azobenzene derivatives are sensibly expensive and applicable dyes accompanied with good antimicrobial and anticancer activities. Originality/value A common process could be affording textiles of colour and antibacterial assets. The newly synthesized dyes containing thiazolidinone moieties with azobenzene coupler showed interesting disperse colourant for polyester with good antibacterial activity.

Berberine sulfate: antimicrobial activity, bioassay, and mode of action

1969 ◽  
Vol 15 (9) ◽  
pp. 1067-1076 ◽  
Author(s):  
A. H. Amin ◽  
T. V. Subbaiah ◽  
K. M. Abbasi
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Antibacterial Activity ◽  
Deoxyribonucleic Acid ◽  
Test Organism ◽  
Inoculum Size ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Rna And Protein Synthesis ◽  
And Staphylococcus Aureus

Berberine sulfate was shown to possess antimicrobial activity against a wide variety of microorganisms including Gram-positive and Gram-negative bacteria, fungi, and protozoa. The antibacterial activity against Vibrio cholerae and Staphylococcus aureus was dependent on the inoculum size of the test organism and pH of the medium. A method of microbiological assay sensitive to 5–10 μg/ml of the drug was developed. The drug was shown to exert a more rapid antibacterial activity than chloramphenicol and tetracycline on V. cholerae, the K values being 2.4 ×10−2 sec−1, 7.8 × 10−3 sec−1, and 5.2 × 10−3 sec−1 respectively. Berberine sulfate was shown to be bacteriocidal to V. cholerae and bacteriostatic to S. aureus, at concentrations of 35 and 50 μg/ml. In both these organisms concentrations of 35 and 50 μg/ml of the drug inhibited ribonucleic acid (RNA) and protein synthesis almost immediately after the addition of the drug. There was little effect on deoxyribonucleic acid (DNA) synthesis at these concentrations.

scholarly journals Membrane Protein Complex ExbB4-ExbD1-TonB1from Escherichia coli Demonstrates Conformational Plasticity

2015 ◽  
Vol 197 (11) ◽  
pp. 1873-1885 ◽  
Author(s):  
Aleksandr Sverzhinsky ◽  
Jacqueline W. Chung ◽  
Justin C. Deme ◽  
Lucien Fabre ◽  
Kristian T. Levey ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Iron Acquisition ◽  
Proton Translocation ◽  
Three Dimensional ◽  
Structural Data ◽  
Structural Features ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Content Type

ABSTRACTIron acquisition at the outer membrane (OM) of Gram-negative bacteria is powered by the proton motive force (PMF) of the cytoplasmic membrane (CM), harnessed by the CM-embedded complex of ExbB, ExbD, and TonB. Its stoichiometry, ensemble structural features, and mechanism of action are unknown. By panning combinatorial phage libraries, periplasmic regions of dimerization between ExbD and TonB were predicted. Using overexpression of full-length His6-taggedexbB-exbDand S-taggedtonB, we purified detergent-solubilized complexes of ExbB-ExbD-TonB fromEscherichia coli. Protein-detergent complexes of ∼230 kDa with a hydrodynamic radius of ∼6.0 nm were similar to previously purified ExbB4-ExbD2complexes. Significantly, they differed in electronegativity by native agarose gel electrophoresis. The stoichiometry was determined to be ExbB4-ExbD1-TonB1. Single-particle electron microscopy agrees with this stoichiometry. Two-dimensional averaging supported the phage display predictions, showing two forms of ExbD-TonB periplasmic heterodimerization: extensive and distal. Three-dimensional (3D) particle classification showed three representative conformations of ExbB4-ExbD1-TonB1. Based on our structural data, we propose a model in which ExbD shuttles a proton across the CM via an ExbB interprotein rearrangement. Proton translocation would be coupled to ExbD-mediated collapse of extended TonB in complex with ligand-loaded receptors in the OM, followed by repositioning of TonB through extensive dimerization with ExbD. Here we present the first report for purification of the ExbB-ExbD-TonB complex, molar ratios within the complex (4:1:1), and structural biology that provides insights into 3D organization.IMPORTANCEReceptors in the OM of Gram-negative bacteria allow entry of iron-bound siderophores that are necessary for pathogenicity. Numerous iron-acquisition strategies rely upon a ubiquitous and unique protein for energization: TonB. Complexed with ExbB and ExbD, the Ton system links the PMF to OM transport. Blocking iron uptake by targeting a vital nanomachine holds promise in therapeutics. Despite much research, the stoichiometry, structural arrangement, and molecular mechanism of the CM-embedded ExbB-ExbD-TonB complex remain unreported. Here we demonstratein vitroevidence of ExbB4-ExbD1-TonB1complexes. Using 3D EM, we reconstructed the complex in three conformational states that show variable ExbD-TonB heterodimerization. Our structural observations form the basis of a model for TonB-mediated iron acquisition.

scholarly journals Аntibacterial inorganic agents: efficiency of using multicomponent systems

2020 ◽  
Vol 10 (4) ◽  
pp. 639-654
Author(s):  
А. A. Meleshko ◽  
A. G. Afinogenova ◽  
G. E. Afinogenov ◽  
A. A. Spiridonova ◽  
V. P. Tolstoy
Keyword(s):  
Antimicrobial Activity ◽  
Antibacterial Activity ◽  
Antimicrobial Agents ◽  
Metal Oxide Nanoparticles ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Nanoscale Systems ◽  
Gram Negative ◽  
Low Toxicity

Metal and metal oxide nanoparticles (NPs) are promising antibacterial agents. They have a broad antimicrobial activity against both Gram-positive and Gram-negative bacteria, viruses, and protozoans. The use of NPs reduces the possibility of the microbial resistance development. This review briefly shows the general mechanisms and the main factors of antibacterial activity of NPs. In this article, a comprehensive review of the recent researches in the field of new antimicrobial agents with superior long-term bactericidal activity and low toxicity is provided. The review gives the examples of synthesis of double and triple nanocomposites based on following oxides: CuO, ZnO, Fe3O4, Ag2O, MnO2, etc. including metal and nonmetal doped nanocomposites (for example with Ag, Ce, Cr, Mn, Nd, Co, Sn, Fe, N, F, etc.). Compared with bactericidal action of individual oxides, the nanocomposites demonstrate superior antibacterial activity and have synergistic effects. For example, the antimicrobial activity of ZnO against both Gram-positive and Gram-negative bacteria was increased by -100% by formation of triple nanocomposites ZnO—MnO2—Cu2O or ZnO—Ag2O—Ag2S. Similar effect was showed for Ce-doped ZnO and Zn-doped CuO. The present article also provides the examples of nanocomposites containing NPs and organic (chitosan, cellulose, polyvinylpyrrolidone, biopolymers, etc.) or inorganic materials with special structure (graphene oxide, TiO2 nanotubes, silica) which demonstrate controlled release and longterm antibacterial activity. All of the considered nanocomposites and their combinations have a pronounced long-term antimicrobial effect including against antibiotic-resistant strains. They are able to prevent the formation of microbial biofilms on biotic and abiotic surfaces, have low toxicity to eukaryotic cells, demonstrate anti-inflammatory and woundhealing properties in compositions with polymers (sodium alginate, collagen, polyvinylpyrrolidone, etc.). The use of nanoscale systems can solve several important practical problems at the same time: saving of long-term antimicrobial activities while reducing the number of compounds, creation of new antimicrobial agents with low toxicity and reduced environmental impact, development of new biocidal materials, including new coatings for effective antimicrobial protection of medical devices.

scholarly journals ANTIMICROBIAL ACTIVITIES OF ARTABOTRYS ODORATISSIMUS R.Br.

2021 ◽  
Vol 3 (1) ◽  
pp. 1-5
Author(s):  
Poonam Sethi ◽  
Nandhagopal Karmegam
Keyword(s):  
Antimicrobial Activity ◽  
Antibacterial Activity ◽  
Pseudomonas Fluorescens ◽  
Methanolic Extract ◽  
Antimicrobial Activities ◽  
Experimental Plant ◽  
Gram Negative Bacteria ◽  
Zone Of Inhibition ◽  
Gram Negative ◽  
Good Antibacterial Activity

ABSTRACT Artabotrys odoratissimus R.Br.  (Annonaceae) a medium sizes shrub with hooks, sweet smelling flowers and aggregate fruits, was tested for activity against gram negative bacteria. The fruit of the experimental plant was extracted with water, methanol and toluene: methanol (2:1 v/v). Artabotrys fruits showed good antibacterial activity and produced zone of inhibition of 32mm. The methanolic extract of the fruit showed maximum zone of inhibition at 300 ?g/ml against Pseudomonas fluorescens. The present study clearly indicates that A. odoratissimus had a profound antimicrobial   activity and it may be useful in the treatment of various infectious caused by bacteria. Keywords: Artabotrys, Gram Negative Bacteria, Pseudomonas, Zone Of Inhibition

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