scholarly journals TetX Is a Flavin-dependent Monooxygenase Conferring Resistance to Tetracycline Antibiotics

2004 ◽  
Vol 279 (50) ◽  
pp. 52346-52352 ◽  
Author(s):  
Wangrong Yang ◽  
Ian F. Moore ◽  
Kalinka P. Koteva ◽  
David C. Bareich ◽  
Donald W. Hughes ◽  
...  
Keyword(s):  
Antimicrobial Agents ◽  
Anaerobic Bacteria ◽  
Tetracycline Antibiotics ◽  
Active Efflux ◽  
Mass Spectral ◽  
Nmr Characterization ◽  
Antibiotic Degradation

The tetracycline antibiotics block microbial translation and constitute an important group of antimicrobial agents that find broad clinical utility. Resistance to this class of antibiotics is primarily the result of active efflux or ribosomal protection; however, a novel mechanism of resistance has been reported to be oxygen-dependent destruction of the drugs catalyzed by the enzyme TetX. Paradoxically, thetetXgenes have been identified on transposable elements found in anaerobic bacteria of the genusBacteroides. Overexpression of recombinant TetX inEscherichia colifollowed by protein purification revealed a stoichiometric complex with flavin adenine dinucleotide. Reconstitution ofin vitroenzyme activity demonstrated a broad tetracycline antibiotic spectrum and a requirement for molecular oxygen and NADPH in antibiotic degradation. The tetracycline products of TetX activity were unstable at neutral pH, but mass spectral and NMR characterization under acidic conditions supported initial monohydroxylation at position 11a followed by intramolecular cyclization and non-enzymatic breakdown to other undefined products. TetX is therefore a FAD-dependent monooxygenase. The enzyme not only catalyzed efficient degradation of a broad range of tetracycline analogues but also conferred resistance to these antibioticsin vivo. This is the first molecular characterization of an antibiotic-inactivating monooxygenase, the origins of which may lie in environmental bacteria.

scholarly journals New oxadiazole derivatives of isonicotinohydrazide in the search for antimicrobial agents: Synthesis and in vitro evaluation

2012 ◽  
Vol 77 (1) ◽  
pp. 9-16 ◽  
Author(s):  
Manav Malhotra ◽  
Mohit Sanduja ◽  
Abdul Samad ◽  
Aakash Deep
Keyword(s):  
Antimicrobial Agents ◽  
Fungal Strain ◽  
Spectral Studies ◽  
Dilution Method ◽  
Mass Spectral ◽  
Oxadiazole Derivatives ◽  
Derivatives Of ◽  
And Staphylococcus Aureus

Structural modification of the front line antitubercular drug isoniazid provide a lipophilic adaptations of the drug in which hydrazide moiety of isoniazid is replaced by 1,3,4-oxadiazole heterocycles to eliminate in-vivo acetylation by arylamine N-acetyltransferase which results to form inactive acetylated drug. In the present study a series of sixteen oxadiazole derivatives were synthesized and characterized by (IR, 1H NMR, 13C NMR and Mass spectral) studies. All the synthesized compounds were evaluated for their antimicrobial activity by broth dilution method against two Gram positive strains (Bacillus subtilis and Staphylococcus aureus), two Gram negative strains (Pseudomonas aeruginosa and Escherichia coli) and fungal strain (Candida albicans and Aspergillus niger). The minimum inhibitory concentration of the compounds was in the range of 1.56-50 ?g ml-1 against bacterial and fungal strain. The results revealed that all synthesized compounds have a significant biological activity against the tested microorganisms. Among the synthesized derivatives 4g, 4h, 4m and 4p were found to be most effective antimicrobial compounds.

scholarly journals In Vivo, In Vitro, and In Silico Characterization of Peptoids as Antimicrobial Agents

PLoS ONE ◽  
2016 ◽  
Vol 11 (2) ◽  
pp. e0135961 ◽  
Author(s):  
Ann M. Czyzewski ◽  
Håvard Jenssen ◽  
Christopher D. Fjell ◽  
Matt Waldbrook ◽  
Nathaniel P. Chongsiriwatana ◽  
...  
Keyword(s):  
In Silico ◽  
Antimicrobial Agents ◽  
In Silico Characterization

scholarly journals Synthesis and characterization of barbitones as antimicrobial agents

2006 ◽  
Vol 71 (6) ◽  
pp. 587-591 ◽  
Author(s):  
H.G. Sangani ◽  
K.B. Bhimani ◽  
R.C. Khunt ◽  
A.R. Parikh
Keyword(s):  
Antimicrobial Activity ◽  
Barbituric Acid ◽  
Antimicrobial Agents ◽  
Spectral Studies ◽  
Synthesis And Characterization ◽  
Mass Spectral ◽  
Elemental Analyses ◽  
Bacteria And Fungi

Barbitones (3) were synthesised by the condensation of chalcones (2) with barbituric acid. The structure of the synthesized compounds were assigned on the basis of elemental analyses, IR, NMR and mass spectral studies. All the products were evaluated for their in vitro antimicrobial activity against various strains of bacteria and fungi.

scholarly journals Genetics of Streptomyces rimosus, the Oxytetracycline Producer

2006 ◽  
Vol 70 (3) ◽  
pp. 704-728 ◽  
Author(s):  
Hrvoje Petković ◽  
John Cullum ◽  
Daslav Hranueli ◽  
Iain S. Hunter ◽  
Nataša Perić-Concha ◽  
...  
Keyword(s):  
Genetic Instability ◽  
Clinical Use ◽  
Streptomyces Rimosus ◽  
Emerging Infections ◽  
Tetracycline Antibiotics ◽  
Genetic Manipulations ◽  
Near Term

SUMMARY From a genetic standpoint, Streptomyces rimosus is arguably the best-characterized industrial streptomycete as the producer of oxytetracycline and other tetracycline antibiotics. Although resistance to these antibiotics has reduced their clinical use in recent years, tetracyclines have an increasing role in the treatment of emerging infections and noninfective diseases. Procedures for in vivo and in vitro genetic manipulations in S. rimosus have been developed since the 1950s and applied to study the genetic instability of S. rimosus strains and for the molecular cloning and characterization of genes involved in oxytetracycline biosynthesis. Recent advances in the methodology of genome sequencing bring the realistic prospect of obtaining the genome sequence of S. rimosus in the near term.

scholarly journals UPLC-ESI-MS/MS Based Characterization of Active Flavonoids from Apocynum spp. and Anti-Bacteria Assay

Antioxidants ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1901
Author(s):  
Gang Gao ◽  
Ning Liu ◽  
Chunming Yu ◽  
Ping Chen ◽  
Jikang Chen ◽  
...  
Keyword(s):  
Antimicrobial Agents ◽  
Radical Scavenging ◽  
Cell Integrity ◽  
Esi Ms ◽  
Potential Applications ◽  
Apocynum Venetum ◽  
Future Potential

In the current study, the active flavonoids from Apocynum venetum and Apocynum hendersonii leaf were efficiently characterized using UPLC-ESI-MS/MS, and yielding the highest content of 15.35 mg/g (A. venetum) and 13.28 mg/g (A. hendersonii) respectively. The antioxidant assay in vitro showed that the isolated flavonoid ingredient groups exhibited free radical scavenging activities to DPPH, ABTS and linoleic acid. The antimicrobial assay revealed the isolated flavonoid ingredient from both A. venetum and A. hendorsonii have exerted anti-MRSA and anti-P. aeruginosa effect through disrupting cell integrity and declining ATP. In vivo assay demonstrated that these flavonoid ingredients effectively accelerated MRSA-infected and P. aeruginosa-infected Balb/c mice wound healing. In summary, these results showed that the characterized flavonoid ingredients exhibited great potential as natural antioxidant and antimicrobial agents, and shed light into future potential applications of Apocynum spp.

scholarly journals Synthesis and Characterization of Chemical Compounds Derived From Benzohydrazide and Evaluation of Their Antibacterial Activities

2021 ◽  
Vol 8 (1) ◽  
pp. 5-10
Author(s):  
Maryam Alizadeh ◽  
Ashraf Kariminik ◽  
Ali Akbari
Keyword(s):  
Pathogenic Bacteria ◽  
Antimicrobial Agents ◽  
Choline Chloride ◽  
Antibacterial Activities ◽  
Simple Method ◽  
Major Health Problem ◽  
Ft Ir

Background: The antimicrobial resistance of pathogenic bacteria has emerged as a major health problem in recent years. Extensive research has been conducted to find new antimicrobial agents. Objectives: The aim of this study was to examine the antibacterial activities of benzohydrazide derivatives. Methods: Manganese hydrogen sulfate choline chloride was applied in a simple method for synthesizing benzohydrazide derivatives. Antibacterial activities of the derivatives were assessed against Staphylococcus aureus, Escherichia coli, Enterococcus faecalis, Bacillus subtilis, diphtheroids, Salmonella enterica, Serratia marcescens, Pseudomonas aeruginosa, and Klebsiella pneumoniae. The structure of the synthesized compounds was determined employing 1 H/13C NMR and Fourier-transform infrared (FT-IR) spectroscopy. The reactions were carried out in choline chloride dissolved in water at room temperature. Results: The results of this study showed that benzohydrazide derivatives had very desired antibacterial activities against the assessed bacteria. Conclusions: Further investigations are required to assess the safety and efficacy of benzohydrazide derivatives as antibacterial agents in vivo and in vitro.

Rapid, Refined, and Robust Method for Expression, Purification, and Characterization of Recombinant Human Amyloid-beta M1-42

2019 ◽  
Author(s):  
Priya Prakash ◽  
Travis Lantz ◽  
Krupal P. Jethava ◽  
Gaurav Chopra
Keyword(s):  
Amyloid Beta ◽  
Western Blots ◽  
Force Microscopy ◽  
E Coli ◽  
Atomic Force ◽  
Set Up ◽  
Short Time

Amyloid plaques found in the brains of Alzheimer’s disease (AD) patients primarily consists of amyloid beta 1-42 (Ab42). Commercially, Ab42 is synthetized using peptide synthesizers. We describe a robust methodology for expression of recombinant human Ab(M1-42) in Rosetta(DE3)pLysS and BL21(DE3)pLysS competent E. coli with refined and rapid analytical purification techniques. The peptide is isolated and purified from the transformed cells using an optimized set-up for reverse-phase HPLC protocol, using commonly available C18 columns, yielding high amounts of peptide (~15-20 mg per 1 L culture) in a short time. The recombinant Ab(M1-42) forms characteristic aggregates similar to synthetic Ab42 aggregates as verified by western blots and atomic force microscopy to warrant future biological use. Our rapid, refined, and robust technique to purify human Ab(M1-42) can be used to synthesize chemical probes for several downstream in vitro and in vivo assays to facilitate AD research.

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