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Assay concordance between SPA and TR-FRET in high-throughput screening.

High-throughput screening (HTS) of large chemical libraries has become the main source of new lead compounds for drug development. Several specialized detection technologies have been developed to facilitate the cost- and time-efficient screening of millions of compounds. However, concerns have been raised, claiming that different HTS technologies may produce different hits, thus limiting trust in the reliability of HTS data. This study was aimed to investigate the reliability of the authors most frequently used assay techniques: scintillation proximity assay (SPA) and homogeneous time-resolved fluorescence resonance energy transfer (TR-FRET). To investigate the data concordance between these 2 detection technologies, the authors screened a large subset of the Schering compound library consisting of 300,000 compounds for inhibitors of a nonreceptor tyrosine kinase. They chose to set up this study in realistic HTS scale to ensure statistical significance of the results. The findings clearly demonstrate that the choice of detection technology has no significant impact on hit finding, provided that assays are biochemically equivalent. Data concordance is up to 90%. The little differences in hit findings are caused by threshold setting but not by systematic differences between the technologies. The most significant difference between the compared techniques is that in the SPA format, more false-positive primary hits were obtained.

Biological Assay↗

High-throughput protein crystallization.

High-throughput structural biology is a focus of a number of academic and pharmaceutical laboratories around the world. The use of X-ray crystallography in these efforts is critically dependent on high-throughput protein crystallization. The application of current protocols yields crystal leads for approximately 30% of the input proteins and well-diffracting crystals for a smaller fraction. Increasing the success rate will require a multidisciplinary approach that must invoke techniques from molecular biology, protein biochemistry, biophysics, artificial intelligence, and automation.

Automation↗

Inhibition of self-splicing group I intron RNA: high-throughput screening assays.

High-throughput screening assays have been developed to rapidly identify small molecule inhibitors targeting catalytic group I introns. Biochemical reactions catalyzed by a self-splicing group I intron derived from Pneumocystis carinii or from bacteriophage T4 have been investigated. In vitro biochemical assays amenable to high-throughput screening have been established. Small molecules that inhibit the functions of group I introns have been identified. These inhibitors should be useful in better understanding ribozyme catalysis or in therapeutic intervention of group I intron-containing microorganisms.

Bacteriophage T4↗

Colorimetric approach to high-throughput mutation analysis.

High-throughput genomic mutation screening for primary tumors has characteristically been expensive, labor-intensive, and inadequate to detect low levels of mutation in a background of wild-type signal. We present a new, combined PCR and colorimetric approach that is inexpensive, simple, and can detect the presence of 1% mutation in a background of wild-type. We compared manual dideoxy sequencing of p53 for eight lung cancer samples to a novel assay combining a primer extension step and an enzymatic colorimetric step in a 96-well plate with covalently attached oligonucleotide sequences. For every sample, we were able to detect the presence or absence of the specific mutation with a statistically significant difference between the sample optical density (OD) and the background OD, with a sensitivity and specificity of 100%. This assay is straightforward, accurate, inexpensive, and allows for rapid, high-throughput analysis of samples, making it ideal for genomic mutation or polymorphism screening studies in both clinical and research settings.

Biological Assay↗

Determining the optimal size of small molecule mixtures for high throughput NMR screening.

High-throughput screening (HTS) using NMR spectroscopy has become a common component of the drug discovery effort and is widely used throughout the pharmaceutical industry. NMR provides additional information about the nature of small molecule-protein interactions compared to traditional HTS methods. In order to achieve comparable efficiency, small molecules are often screened as mixtures in NMR-based assays. Nevertheless, an analysis of the efficiency of mixtures and a corresponding determination of the optimum mixture size (OMS) that minimizes the amount of material and instrumentation time required for an NMR screen has been lacking. A model for calculating OMS based on the application of the hypergeometric distribution function to determine the probability of a "hit" for various mixture sizes and hit rates is presented. An alternative method for the deconvolution of large screening mixtures is also discussed. These methods have been applied in a high-throughput NMR screening assay using a small, directed library.

Chemistry, Pharmaceutical↗

A bioluminescent sensor for high throughput toxicity classification.

A high throughput toxicity monitoring and classification biosensor system has been successfully developed using four immobilized bioluminescent Escherichia coli strains, DPD2511, DPD2540, DPD2794 and TV1061, which have plasmids bearing a fusion of a specific promoter to the luxCDABE operon. The bioluminescence of DPD2511 increases in the presence of oxidative damage, DPD2540 by membrane damage, DPD2794 by DNA damage and TV1061 by protein damage. In the developed biosensor these strains are immobilized in a single 96 well plate using an LB-agar matrix, and are able to detect the toxicities of hydrogen peroxide, phenol and mitomycin C in water samples. As the concentration of each chemical was increased, the bioluminescence levels from the corresponding wells, containing either DPD2511, DPD2540, DPD2794 or TV1061, increased. This increase in bioluminescence followed a dose dependent response to the toxic chemicals within a specific concentration range. In particular, each test requires only 4 h to give clear bioluminescent response signature. Storage of the biosensor at 4 degrees C for 2 weeks caused no change in its dose-dependent response. The fast and easy detection of oxidative, membrane, protein and DNA damaging agents in aqueous environments is possible due to the high throughput capability of this biosensor.

Biosensing Techniques↗

High throughput detection of microsatellite instability by denaturing high-performance liquid chromatography.

Microsatellite instability (MSI) is a hallmark of the DNA replication error phenotype, due to the inactivation of mismatch repair genes. MSI has been implicated in colon and many other gastrointestinal cancers. MSI usually can be analyzed by PCR amplification of microsatellite markers followed by electrophoresis and detected using autoradiography or fluorescence techniques. We report here a novel method for high-throughput detection of MSI using denaturing high performance liquid chromatography (DHPLC). Amplification of two mononucleotide markers (BAT25 and BAT26) by polymerase chain reaction (PCR) is followed by DHPLC analysis to display alteration in the length of repetitive sequences. These two markers were tested in 84 colorectal cancer samples confirmed to be 44 MSI-H and 40 MSI-L or MSS, previously defined by multiple microsatellite markers and/or by immunohistochemical analyses of MLH1 and MSH2 proteins. Among 44 MSI-H samples, sequence variations in BAT26 and BAT25 were detected in 44 (100%) and 43 (98%), respectively, while no sequence variation in the two markers was detected in 40 MSI-L or MSS samples. A total of 96 gastric cancers and their matched normal tissues were then analyzed for MSI-H using this method. Sequence variations in BAT26 and BAT25 were detected in nine (9.4%) samples. Seven of the nine cases were shown unstable at both BAT26 and BAT25; one each was unstable at BAT26 or BAT25. These results were confirmed by autoradiography analyses. Together, our results demonstrate high sensitivity and specificity of DHPLC in the analysis of sequence variations in BAT25 and BAT26 to determine MSI status. This simple, efficient, and high-throughput approach will facilitate analysis of MSI in large sample sets of any cancers.

Chromatography, High Pressure Liquid↗

New assay technologies for high-throughput screening.

The use of high-throughput screening for early stage drug discovery imposes several constraints on the format of assays for therapeutic targets of interest. Homogeneous cell-free assays based on energy transfer, fluorescence polarization spectroscopy or fluorescence correlation spectroscopy provide the sensitivity, ease, speed and resistance to interference from test compounds needed to function in a high-throughput screening mode. Similarly, novel cell-based assays are now being adapted for high-throughput screening, providing for in situ analysis of a variety of biological targets. Finally, recent advances in assay miniaturization mark a transition to ultra high-throughput screening, ensuring that identification of lead compounds will not be the rate-limiting step in finding new drugs.

Animals↗

High-throughput genotyping assay approaches.

High-throughput genotyping approaches are being developed to meet the demands of pharmacogenomnics, where numerous individuals are studied with thousands of single nucleotide polymorphism (SNP) markers. All non-gel-based genotyping approaches achieve allelic discrimination by one of four mechanisms: allele-specific hybridisation, allele-specific primer extension, allele-specific oligonucleotide ligation and allele-specific cleavage of a flap probe. By combining one of these allelic discrimination mechanisms with either a homogeneous or solid-phase reaction format and a detection method such as fluorescence intensity, fluorescence polarisation or mass spectrometry, a number of viable high-throughput genotyping methods have been developed and are being readied for routine use. With the biochemistry for robust genotyping in place, good engineering solutions are needed to make high-throughput genotyping a reality.

DNA Primers↗

SwellGel: a sample preparation affinity chromatography technology for high throughput proteomic applications.

Development of high throughput systems for purification and analysis of proteins is essential for the success of today's proteomic research. We have developed an affinity chromatography technology that allows the customization of high capacity/high throughput chromatographic separation of proteins. This technology utilizes selected chromatography media that are dehydrated to form uniform SwellGel discs. Unlike wet resin slurries, these discs are easily adaptable to a variety of custom formats, eliminating problems associated with resin dispensing, equilibration, or leakage. Discs can be made in assorted sizes (resin volume 15 microl-3 ml) dispensed in various formats (384-, 96-, 48-, and 24-well microplates or columns) and different ligands can be attached to the matrix. SwellGel discs rapidly hydrate upon addition of either water or the protein sample, providing dramatically increased capacity compared to coated plates. At the same time, the discs offer greater stability, reproducibility, and ease of handling than standard wet chromatography resins. We previously reported the development of SwellGel for the purification of 6x His- and glutathione-S-transferase (GST)-tagged fusion proteins [Prot. Exp. Purif. 22 (2001) 359-366]. In this paper, we discuss an expanded list of SwellGel stabilized chromatographic methods that have been adapted to high throughput formats for processing protein samples ranging from 10 microl to 10 ml (1 microg to 50 mg protein). Data are presented applying SwellGel discs to high throughput proteomic applications such as affinity tag purification, protein desalting, the removal of abundant proteins from serum including albumin and immunoglobulin, and the isolation of phosphorylated peptides for mass spectrometry.

Albumins↗

A high-throughput assay for cyclic nucleotide phosphodiesterases.

The search for cyclic nucleotide phosphodiesterase inhibitors in large chemical and natural product libraries is limited by assay throughput. A high-throughput assay that can monitor different phosphodiesterase activities would be useful for these inhibitor searches. We have developed a sensitive phosphodiesterase assay which is based on the selective precipitation of the radiolabeled 5'-nucleotide product by zinc and barium. This assay is unique to previous precipitation methods in that it measures product formed, either GMP or AMP. The procedure was adapted to a microtiter plate format for high-throughput, making it possible to perform in excess of 960 assays per day. This method was used to determine accurate enzyme kinetic constants for three different phosphodiesterases. The results agree favorably with literature values. Using the cyclic guanosine 3',5'-monophosphate-specific phosphodiesterase, IC50 values for the inhibitors M&B 22,948 and 3-isobutyl-1-methylxanthine were also determined. Demonstration of appropriate Km and inhibitor IC50 values verifies the ability of this new assay to identify selective cyclic nucleotide phosphodiesterase inhibitors.

3',5'-Cyclic-GMP Phosphodiesterases↗

New developments in high-throughput resequencing and variation detection using high density microarrays.

We developed a high-throughput method for resequencing for single nucleotide polymorphism (SNP) discovery using high-density microarrays. Over the two-year course of this study a number of improvements in sample preparation methods, hybridization assay, array handling, and analysis method were developed and implemented. DNA from 40 unrelated individuals of three different ethnic origins was amplified, labeled, and hybridized to arrays designed with probes representing genomic, coding, and regulatory regions. Protocol improvements including the use of long PCR and semi-automation reduced labeling and fragmentation costs by 33%. Automation improvements include the development of a scanner autoloader for arrays, a faster array wash station, and a linked laboratory tracking and data management system. Validation of a smaller feature size, 20 x 24 microns, allowed the simultaneous screening of 30-kb sense and 30-kb antisense DNA on each microarray, increasing throughput to 1.4 Mb per day per two laboratory personnel. More than 15,000 SNPs were identified in 8.3 Mb of the human genome using high-density resequencing and variation detection arrays (microarrays).

Automation↗

Automated crystallographic system for high-throughput protein structure determination.

High-throughput structural genomic efforts require software that is highly automated, distributive and requires minimal user intervention to determine protein structures. Preliminary experiments were set up to test whether automated scripts could utilize a minimum set of input parameters and produce a set of initial protein coordinates. From this starting point, a highly distributive system was developed that could determine macromolecular structures at a high throughput rate, warehouse and harvest the associated data. The system uses a web interface to obtain input data and display results. It utilizes a relational database to store the initial data needed to start the structure-determination process as well as generated data. A distributive program interface administers the crystallographic programs which determine protein structures. Using a test set of 19 protein targets, 79% were determined automatically.

Automation↗

Capillary array reversed-phase liquid chromatography-based multidimensional separation system coupled with MALDI-TOF-TOF-MS detection for high-throughput proteome analysis.

A high-throughput on-line capillary array-based two-dimensional liquid chromatography (2D-LC) system coupled with MALDI-TOF-TOF-MS proteomics analyzer for comprehensive proteomic analyses has been developed, in which one capillary strong-cation exchange (SCX) chromatographic column was used as the first separation dimension and 18 parallel capillary reversed-phase liquid chromatographic (RPLC) columns were integrated as the second separation dimension. Peptides bound to the SCX phase were "stepped" off using multiple salt pulses followed by sequentially loading of each subset of peptides onto the corresponding precolumns. After salt fractionation, by directing identically split solvent-gradient flows into 18 channels, peptide fractions were concurrently back-flushed from the precolumns and separated simultaneously with 18 capillary RP columns. LC effluents were directly deposited onto the MALDI target plates through an array of capillary tips at a 15-s interval, and then alpha-cyano-4-hydroxycinnamic acid (CHCA) matrix solution was added to each sample spot for subsequent MALDI experiments. This new system allows an 18-fold increase in throughput compared with serial-based 2D-LC system. The high efficiency of the overall system was demonstrated by the analysis of a tryptic digest of proteins extracted from normal human liver tissue. A total of 462 proteins was identified, which proved the system's promising potential for high-throughput analysis and application in proteomics.

Capillary Action↗

Gene expression analysis for high throughput screening applications.

To meet growing needs for high throughput gene expression profiling, we established a new automated high throughput TaqMan RT-PCR method for quantitative mRNA expression analysis. In this method, the Allegro( trade mark ) (Zymark) system conducts all sample tracking and liquid handling steps, and ABI PRISM 7900 HT (Applied Biosystems) is used to conduct real-time determination of the C(t) value when amplification of PCR products is first detected and accumulation of inhibitory PCR products is unlikely to occur. The ABI PRISM 7900 HT Sequence Detection System features a real-time PCR instrument with 384-well-plate compatibility and robotic loading, and continuous wavelength detection, which enables the use of multiple fluorophores in a single reaction. The Allegro System offers an assembly line approach with a modular design that allows reconfiguration of the components to accommodate variations in the assay flow. In the present study, we have established and validated a new automated High Throughput (HT) TaqMan RT-PCR- based method for quantitative mRNA expression analysis. The data demonstrate that HT-Taqman PCR is a powerful tool that can be used for measuring low concentrations of mRNA, and is highly accurate, reproducible, and amenable to high throughput analysis. Results suggest that HT-TaqMan is a reliable method for the quantification of low-expression genes and a powerful tool with HT capability for target identification/validation, structure-activity relationship (SAR) study, compound selection for efficacy studies, and biomarker identification in drug discovery and development.

Drug Design↗

Experimental standards for high-throughput proteomics.

Proteome analysis, utilizing high-throughput proteomics approaches, involves studying proteins that a whole organism (or specific tissue or cellular compartment) expresses under certain conditions. Intrinsic difficulties of these studies, as well as the enormous volumes of data they typically produce, make the proteome analysis and interpretation very difficult. As with any high-throughput approach, proteomics experiments should be carefully designed, analyzed, and verified. In addition to computational standards,experimental standards--simple and complex mixtures of known proteins--for high-throughput proteomics have to be developed and utilized. This article discusses such experimental standards and their implementations.

Animals↗

SetBERT: the deep learning platform for contextualized embeddings and explainable predictions from high-throughput sequencing.

MOTIVATION: High-throughput sequencing (HTS) is a modern sequencing technology used to profile microbiomes by sequencing thousands of short genomic fragments from the microorganisms within a given sample. This technology presents a unique opportunity for artificial intelligence to comprehend the underlying functional relationships of microbial communities. However, due to the unstructured nature of HTS data, nearly all computational models are limited to processing DNA sequences individually. This limitation causes them to miss out on key interactions between microorganisms, significantly hindering our understanding of how these interactions influence the microbial communities as a whole. Furthermore, most computational methods rely on post-processing of samples which could inadvertently introduce unintentional protocol-specific bias. RESULTS: Addressing these concerns, we present SetBERT, a robust pre-training methodology for creating generalized deep learning models for processing HTS data to produce contextualized embeddings and be fine-tuned for downstream tasks with explainable predictions. By leveraging sequence interactions, we show that SetBERT significantly outperforms other models in taxonomic classification with genus-level classification accuracy of 95%. Furthermore, we demonstrate that SetBERT is able to accurately explain its predictions autonomously by confirming the biological-relevance of taxa identified by the model. AVAILABILITY AND IMPLEMENTATION: All source code is available at https://github.com/DLii-Research/setbert. SetBERT may be used through the q2-deepdna QIIME 2 plugin whose source code is available at https://github.com/DLii-Research/q2-deepdna.

Deep Learning↗

Screening and synthesis: high throughput technologies applied to parasitology.

High throughput technologies continue to develop in response to the challenges set by the genome projects. This article discusses how the techniques of both high throughput screening (HTS) and synthesis can influence research in parasitology. Examples of the use of targeted and phenotype-based HTS using unbiased compound collections are provided. The important issue of identifying the protein target(s) of bioactive compounds is discussed from the synthetic chemist's perspective. This article concludes by reviewing recent examples of successful target identification studies in parasitology.

Animals↗