scholarly journals A Homogeneous, High-Throughput Fluorescence Anisotropy-Based DNA Supercoiling Assay

2010 ◽  
Vol 15 (9) ◽  
pp. 1088-1098 ◽  
Author(s):  
Adam Shapiro ◽  
Haris Jahic ◽  
Swati Prasad ◽  
David Ehmann ◽  
Jason Thresher ◽  
...  
Keyword(s):  
High Throughput ◽  
Fluorescence Anisotropy ◽  
High Throughput Screening ◽  
Topoisomerase I ◽  
Dna Supercoiling ◽  
New Drugs ◽  
E Coli ◽  
Cellular Processes ◽  
The Difference ◽  
Cellular Replication

The degree of supercoiling of DNA is vital for cellular processes, such as replication and transcription. DNA topology is controlled by the action of DNA topoisomerase enzymes. Topoisomerases, because of their importance in cellular replication, are the targets of several anticancer and antibacterial drugs. In the search for new drugs targeting topoisomerases, a biochemical assay compatible with automated high-throughput screening (HTS) would be valuable. Gel electrophoresis is the standard method for measuring changes in the extent of supercoiling of plasmid DNA when acted upon by topoisomerases, but this is a low-throughput and laborious method. A medium-throughput method was described previously that quantitatively distinguishes relaxed and supercoiled plasmids by the difference in their abilities to form triplex structures with an immobilized oligonucleotide. In this article, the authors describe a homogeneous supercoiling assay based on triplex formation in which the oligonucleotide strand is labeled with a fluorescent dye and the readout is fluorescence anisotropy. The new assay requires no immobilization, filtration, or plate washing steps and is therefore well suited to HTS for inhibitors of topoisomerases. The utility of this assay is demonstrated with relaxation of supercoiled plasmid by Escherichia coli topoisomerase I, supercoiling of relaxed plasmid by E. coli DNA gyrase, and inhibition of gyrase by fluoroquinolones and nalidixic acid.

Large-scale High-throughput Screening Revealed 5'-(carbonylamino)-2,3'- bithiophene-4'-carboxylate as Novel Template for Antibacterial Agents

2020 ◽  
Vol 17 (5) ◽  
pp. 716-724
Author(s):  
Yan A. Ivanenkov ◽  
Renat S. Yamidanov ◽  
Ilya A. Osterman ◽  
Petr V. Sergiev ◽  
Vladimir A. Aladinskiy ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
High Throughput ◽  
High Throughput Screening ◽  
Large Scale ◽  
Antibacterial Agents ◽  
Sos Response ◽  
Luciferase Assay ◽  
Translational Machinery ◽  
E Coli ◽  
New Class

Background: The key issue in the development of novel antimicrobials is a rapid expansion of new bacterial strains resistant to current antibiotics. Indeed, World Health Organization has reported that bacteria commonly causing infections in hospitals and in the community, e.g. E. Coli, K. pneumoniae and S. aureus, have high resistance vs the last generations of cephalosporins, carbapenems and fluoroquinolones. During the past decades, only few successful efforts to develop and launch new antibacterial medications have been performed. This study aims to identify new class of antibacterial agents using novel high-throughput screening technique. Methods: We have designed library containing 125K compounds not similar in structure (Tanimoto coeff.< 0.7) to that published previously as antibiotics. The HTS platform based on double reporter system pDualrep2 was used to distinguish between molecules able to block translational machinery or induce SOS-response in a model E. coli system. MICs for most active chemicals in LB and M9 medium were determined using broth microdilution assay. Results: In an attempt to discover novel classes of antibacterials, we performed HTS of a large-scale small molecule library using our unique screening platform. This approach permitted us to quickly and robustly evaluate a lot of compounds as well as to determine the mechanism of action in the case of compounds being either translational machinery inhibitors or DNA-damaging agents/replication blockers. HTS has resulted in several new structural classes of molecules exhibiting an attractive antibacterial activity. Herein, we report as promising antibacterials. Two most active compounds from this series showed MIC value of 1.2 (5) and 1.8 μg/mL (6) and good selectivity index. Compound 6 caused RFP induction and low SOS response. In vitro luciferase assay has revealed that it is able to slightly inhibit protein biosynthesis. Compound 5 was tested on several archival strains and exhibited slight activity against gram-negative bacteria and outstanding activity against S. aureus. The key structural requirements for antibacterial potency were also explored. We found, that the unsubstituted carboxylic group is crucial for antibacterial activity as well as the presence of bulky hydrophobic substituents at phenyl fragment. Conclusion: The obtained results provide a solid background for further characterization of the 5'- (carbonylamino)-2,3'-bithiophene-4'-carboxylate derivatives discussed herein as new class of antibacterials and their optimization campaign.

scholarly journals A High-Throughput Approach To Identify Compounds That Impair Envelope Integrity in Escherichia coli

2016 ◽  
Vol 60 (10) ◽  
pp. 5995-6002 ◽  
Author(s):  
Kristin R. Baker ◽  
Bimal Jana ◽  
Henrik Franzyk ◽  
Luca Guardabassi
Keyword(s):  
Escherichia Coli ◽  
High Throughput ◽  
High Throughput Screening ◽  
Gram Negative Bacteria ◽  
Chromogenic Substrate ◽  
Intrinsic Resistance ◽  
Gram Negative ◽  
Content Type ◽  
E Coli ◽  
Screening Platform

ABSTRACTThe envelope of Gram-negative bacteria constitutes an impenetrable barrier to numerous classes of antimicrobials. This intrinsic resistance, coupled with acquired multidrug resistance, has drastically limited the treatment options against Gram-negative pathogens. The aim of the present study was to develop and validate an assay for identifying compounds that increase envelope permeability, thereby conferring antimicrobial susceptibility by weakening of the cell envelope barrier in Gram-negative bacteria. A high-throughput whole-cell screening platform was developed to measureEscherichia colienvelope permeability to a β-galactosidase chromogenic substrate. The signal produced by cytoplasmic β-galactosidase-dependent cleavage of the chromogenic substrate was used to determine the degree of envelope permeabilization. The assay was optimized by using known envelope-permeabilizing compounds andE. coligene deletion mutants with impaired envelope integrity. As a proof of concept, a compound library comprising 36 peptides and 45 peptidomimetics was screened, leading to identification of two peptides that substantially increased envelope permeability. Compound 79 reduced significantly (from 8- to 125-fold) the MICs of erythromycin, fusidic acid, novobiocin and rifampin and displayed synergy (fractional inhibitory concentration index, <0.2) with these antibiotics by checkerboard assays in two genetically distinctE. colistrains, including the high-risk multidrug-resistant, CTX-M-15-producing sequence type 131 clone. Notably, in the presence of 0.25 μM of this peptide, both strains were susceptible to rifampin according to the resistance breakpoints (R> 0.5 μg/ml) for Gram-positive bacterial pathogens. The high-throughput screening platform developed in this study can be applied to accelerate the discovery of antimicrobial helper drug candidates and targets that enhance the delivery of existing antibiotics by impairing envelope integrity in Gram-negative bacteria.

scholarly journals Accelerating High-Throughput Screening for Structural Materials with Production Management Methods

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1330 ◽  
Author(s):  
Alexander Bader ◽  
Finn Meiners ◽  
Kirsten Tracht
Keyword(s):  
High Throughput ◽  
Material Flow ◽  
High Throughput Screening ◽  
Production Management ◽  
Waiting Times ◽  
Complex Structure ◽  
New Drugs ◽  
Order Processing ◽  
Speed Up ◽  
Process Trial

High-throughput screenings are widely accepted for pharmaceutical developments for new substances and the development of new drugs with required characteristics by evolutionary studies. Current research projects transfer this principle of high-throughput testing to the development of metallic materials. In addition to new generating and testing methods, these types of high-throughput systems need a logistical control and handling method to reduce throughput time to get test results faster. Instead of the direct material flow found in classical high-throughput screenings, these systems have a very complex structure of material flow. The result is a highly dynamic system that includes short-term changes such as rerun stations, partial tests, and temporarily paced sequences between working systems. This paper presents a framework that divides the actions for system acceleration into three main sections. First, methods for special applications in high-throughput systems are designed or adapted to speed up the generation, treatment, and testing processes. Second, methods are needed to process trial plans and to control test orders, which can efficiently reduce waiting times. The third part of the framework describes procedures for handling samples. This reduces non-productive times and reduces order processing in individual lots.

scholarly journals Development of a High-Throughput Cell-Based Assay for Superoxide Production in HL-60 Cells

2010 ◽  
Vol 15 (4) ◽  
pp. 388-397 ◽  
Author(s):  
Patricia M. Seitz ◽  
Rona Cooper ◽  
Gregory J. Gatto ◽  
Fernando Ramon ◽  
Thomas D. Sweitzer ◽  
...  
Keyword(s):  
High Throughput ◽  
High Throughput Screening ◽  
Superoxide Production ◽  
Test Set ◽  
Cellular Processes ◽  
Detection Assay ◽  
Z Value ◽  
Compound Concentration ◽  
Compound Test ◽  
Early Drug

Superoxide affects many normal and pathogenic cellular processes, and the detection of superoxide produced by cells is therefore of interest for potential therapeutic applications. To develop a high-throughput cell-based assay for the detection of extracellular superoxide production that could be run in a 384-well or 1536-well format, 2 luminescent reagents, Lucigenin and Diogenes, and one fluorescent reagent, Oxyburst Green BSA, were tested. HL-60 cells, which had been differentiated to a neutrophil-like phenotype with DMSO and frozen in large batches, were used in assays. All 3 superoxide detection reagents performed well statistically in terms of IC50 reproducibility and met a desired Z′ value requirement of >0.4. When tested against a 1408-compound test set at 5 or 10 µM compound concentration, a higher hit rate was obtained with the 2 luminescent reagents compared with that obtained with the fluorescent Oxyburst Green BSA reagent. The Oxyburst Green BSA assay was ultimately chosen for compound profiling and high-throughput screening activities. This 1536 superoxide detection assay using cryopreserved differentiated HL-60 cells represents a shifting paradigm toward the utilization of more therapeutically relevant cells in early drug development activities.

scholarly journals Antagonism screen for inhibitors of bacterial cell wall biogenesis uncovers an inhibitor of undecaprenyl diphosphate synthase

2015 ◽  
Vol 112 (35) ◽  
pp. 11048-11053 ◽  
Author(s):  
Maya A. Farha ◽  
Tomasz L. Czarny ◽  
Cullen L. Myers ◽  
Liam J. Worrall ◽  
Shawn French ◽  
...  
Keyword(s):  
Cell Wall ◽  
High Throughput ◽  
High Throughput Screening ◽  
Teichoic Acid ◽  
Antibacterial Drug ◽  
Wall Teichoic Acid ◽  
Chemical Screening ◽  
Cellular Processes ◽  
Cell Wall Biogenesis ◽  
Antagonistic Interactions

Drug combinations are valuable tools for studying biological systems. Although much attention has been given to synergistic interactions in revealing connections between cellular processes, antagonistic interactions can also have tremendous value in elucidating genetic networks and mechanisms of drug action. Here, we exploit the power of antagonism in a high-throughput screen for molecules that suppress the activity of targocil, an inhibitor of the wall teichoic acid (WTA) flippase in Staphylococcus aureus. Well-characterized antagonism within the WTA biosynthetic pathway indicated that early steps would be sensitive to this screen; however, broader interactions with cell wall biogenesis components suggested that it might capture additional targets. A chemical screening effort using this approach identified clomiphene, a widely used fertility drug, as one such compound. Mechanistic characterization revealed the target was the undecaprenyl diphosphate synthase, an enzyme that catalyzes the synthesis of a polyisoprenoid essential for both peptidoglycan and WTA synthesis. The work sheds light on mechanisms contributing to the observed suppressive interactions of clomiphene and in turn reveals aspects of the biology that underlie cell wall synthesis in S. aureus. Further, this effort highlights the utility of antagonistic interactions both in high-throughput screening and in compound mode of action studies. Importantly, clomiphene represents a lead for antibacterial drug discovery.

scholarly journals Development of a High-Throughput Scintillation Proximity Assay for the Identification of C-Domain Translational Initiation Factor 2 Inhibitors

2002 ◽  
Vol 7 (6) ◽  
pp. 541-546 ◽  
Author(s):  
Sonia Delle Fratte ◽  
Chiara Piubelli ◽  
Enrico Domenici
Keyword(s):  
High Throughput ◽  
High Throughput Screening ◽  
Ribosomal Subunit ◽  
New Drugs ◽  
Initiation Factor ◽  
Translational Initiation ◽  
Scintillation Proximity Assay ◽  
Initiation Factor 2 ◽  
Subsequent Capture ◽  
Translational Initiation Factor

Translational initiation factor 2 (IF2) is the largest of the 3 factors required for translation initiation in prokaryotes and has been shown to be essential in Escherichia coli. It stimulates the binding of fMet-tRNAfMet to the 30S ribosomal subunit in the presence of GTP. The selectivity is achieved through specific recognition of the tRNAfMet blocked α-amino group. IF2 is composed of 3 structural domains: N-domain, whose function is not known; G-domain, which contains the GTP/GDP binding site and the GTPase catalytic center; and C-domain, which recognizes and binds fMet-tRNAfMet. Its activity is strictly bacteria specific and highly conserved among prokaryotes. So far, antibiotics targeting IF2 function are not known, and this makes it an ideal target for new drugs with mechanisms of resistance not yet developed. A few assays have been developed in the past, which allow the detection of IF2 activity either directly or indirectly. In both instances, the assays are based on radioactive detection and do not allow for high throughput because of the need for separation or solvent extraction steps. The authors describe a novel biochemical assay for IF2 that exploits the molecular recognition of fMet-tRNAfMet by the C-domain. The assay is based on the incubation of biotinyl-IF2 with fMet-tRNAfMet and the subsequent capture of the radiolabeled complex by streptavidin-coated beads, exploiting the scintillation proximity assay (SPA) technology. The assay has been designed in an automatable, homogeneous, miniaturized fashion suitable for high-throughput screening and is rapid, sensitive, and robust to dimethyl sulfoxide (DMSO) up to 10% v/v. The assay, used to screen a limited chemical collection of about 5000 compounds and a subset of compounds originated by a 2-D substructural search, has shown to be able to detect potential IF2 inhibitors.

Hormesis in high-throughput screening of antibacterial compounds in E coli

2010 ◽  
Vol 29 (8) ◽  
pp. 667-677 ◽  
Author(s):  
Edward J Calabrese ◽  
George R Hoffmann ◽  
Edward J Stanek ◽  
Marc A Nascarella
Keyword(s):  
High Throughput ◽  
High Throughput Screening ◽  
Antibacterial Agents ◽  
Threshold Model ◽  
Concentration Effects ◽  
Data Set ◽  
E Coli ◽  
Model Predictions ◽  
High Throughput Study ◽  
Repeat Measure

This article assesses the response below a toxicological threshold for 1888 antibacterial agents in Escherichia coli, using 11 concentrations with twofold concentration spacing in a high-throughput study. The data set had important strengths such as low variability in the control (2%—3% SD), a repeat measure of all wells, and a built-in replication. Bacterial growth at concentrations below the toxic threshold is significantly greater than that in the controls, consistent with a hormetic concentration response. These findings, along with analyses of published literature and complementary evaluations of concentration-response model predictions of low-concentration effects in yeast, indicate a lack of support for the broadly and historically accepted threshold model for responses to concentrations below the toxic threshold.

scholarly journals Nano-biofilm Arrays as a Novel Universal Platform for Microscale Microbial Culture and High-Throughput Downstream Applications

2019 ◽  
Vol 26 (14) ◽  
pp. 2529-2535 ◽  
Author(s):  
Anand Srinivasan ◽  
Anand K. Ramasubramanian ◽  
José L. Lopez-Ribot
Keyword(s):  
High Throughput ◽  
High Throughput Screening ◽  
Antimicrobial Agents ◽  
Microarray Platform ◽  
New Drugs ◽  
Microbial Culture ◽  
Phenotypic Properties ◽  
Microbial Biofilms ◽  
Antibiotic Drug

Biofilms are the predominant mode of microbial growth and it is now fully accepted that a majority of infections in humans are associated with a biofilm etiology. Biofilms are defined as attached and structured microbial communities surrounded by a protective exopolymeric matrix. Importantly, sessile microorganisms growing within a biofilm are highly resistant to antimicrobial agents. Thus, there is an urgent need to develop new and improved anti-biofilm therapies. Unfortunately, most of the current techniques for in-vitro biofilm formation are not compatible with high throughput screening techniques that can speed up discovery of new drugs with anti-biofilm activity. To try to overcome this major impediment, our group has developed a novel technique consisting of micro-scale culture of microbial biofilms on a microarray platform. Using this technique, hundreds to thousands of microbial biofilms, each with a volume of approximately 30-50 nanolitres, can be simultaneously formed on a standard microscope slide. Despite more than three orders of magnitude of miniaturization over conventional biofilms, these nanobiofilms display similar growth, structural and phenotypic properties, including antibiotic drug resistance. These nanobiofilm chips are amenable to automation, drastically reducing assay volume and costs. This technique platform allows for true high-throughput screening in search for new anti-biofilm drugs.

High Throughput Screening for Drug Discovery and Virus Detection

2021 ◽  
Vol 24 ◽  
Author(s):  
Adetola Okea ◽  
Deniz Sahin ◽  
Xin Chen ◽  
Ying Shang
Keyword(s):  
Drug Discovery ◽  
High Throughput ◽  
High Throughput Screening ◽  
Virus Detection ◽  
Flow Time ◽  
New Drugs ◽  
Mixed Integer ◽  
General Process ◽  
Screening Systems

Background: High throughput screening systems are automated labs for the analysis of many biochemical substances in the drug discovery and virus detection process. This paper was motivated by the problem of automating testing for viruses and new drugs using high throughput screening systems. The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) at the turn of 2019-2020 presented extradentary challenges to public health. Existing approaches to test viruses and new drugs do not use optimal schedules and are not efficient. Objective: The scheduling of activities performed by various resources in a high throughput screening system affects its efficiency, throughput, operations cost, and quality of screening. This study aims to minimize the total screening (flow) time and ensure the consistency and quality of screening. Methods: This paper develops innovative mixed integer models that efficiently compute optimal schedules for screening many microplates to identify new drugs and determine whether samples contain viruses. The methods integrate job-shop and cyclic scheduling. Experiments are conducted for a drug discovery process of screening an enzymatic assay and a general process of detecting SARS-CoV-2. Results: The method developed in this article can reduce screening time by as much as 91.67%. Conclusion: The optimal schedules for high throughput screening systems greatly reduce the total flow time and can be computed efficiently to help discover new drugs and detect viruses.

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