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BioAssay: AID 488956

Counterscreen for AddAB inhibitors: absorbance-based bacterial cell-based high throughput confirmation assay for inhibitors of bacterial viability

Name: Counterscreen for AddAB inhibitors: absorbance-based bacterial cell-based high throughput confirmation assay for inhibitors of bacterial viability. ..more
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 Tested Compounds
 Tested Compounds
All(883)
 
 
Active(306)
 
 
Inactive(577)
 
 
 Tested Substances
 Tested Substances
All(885)
 
 
Active(308)
 
 
Inactive(577)
 
 
 Related BioAssays
 Related BioAssays
AID: 488956
Data Source: The Scripps Research Institute Molecular Screening Center (ECOLIV3065VBLTY_INH_ABS_1536_3X%INH CSRUN)
BioAssay Type: Primary, Primary Screening, Single Concentration Activity Observed
Depositor Category: NIH Molecular Libraries Probe Production Network
Deposit Date: 2010-10-27

Data Table ( Complete ):           View Active Data    View All Data
BioActive Compounds: 306
Related Experiments
Show more
AIDNameTypeComment
435030Absorbance-based primary bacterial cell-based high throughput screening assay to identify inhibitors of AddAB recombination protein complexScreeningdepositor-specified cross reference: Primary screen (AddAB recombination protein complex inhibitors in singlicate)
449728Counterscreen for inhibitors of AddAB: absorbance-based bacterial cell-based high throughput screening assay to identify inhibitors of bacterial viabilityScreeningdepositor-specified cross reference: Counterscreen (bacterial viability inhibitors in singlicate)
449731Summary of the probe development effort to identify inhibitors of AddAB recombination protein complexSummarydepositor-specified cross reference: Summary (AddAB recombination protein complex inhibitors)
492957Counterscreen for AddAB inhibitors: absorbance-based bacterial cell-based high throughput dose response assay to identify inhibitors of RecBCDConfirmatorydepositor-specified cross reference
492958Counterscreen for AddAB inhibitors: absorbance-based bacterial cell-based high throughput dose response assay for inhibitors of bacterial viabilityConfirmatorydepositor-specified cross reference
492959Absorbance-based bacterial cell-based high throughput dose response assay for inhibitors of AddAB recombination protein complexConfirmatorydepositor-specified cross reference
504677Late stage results for the probe development effort to identify inhibitors of AddAB recombination protein complex: Absorbance-based bacterial cell-based dose response assay for inhibitors of AddAB recombination protein complexConfirmatorydepositor-specified cross reference
504678Late stage counterscreen results for the probe development effort to identify inhibitors of AddAB recombination protein complexes: absorbance-based bacterial cell-based dose response assay for inhibitors of bacterial viabilityConfirmatorydepositor-specified cross reference
504679Late stage counterscreen results for the probe development effort to identify inhibitors of AddAB recombination protein complex: absorbance-based bacterial cell-based dose response assay to identify inhibitors of RecBCDConfirmatorydepositor-specified cross reference
602421Late stage assay provider assay for AddAB inhibitors: Radioactivity-based biochemical dose response assay to identify inhibitors of the nuclease activity of purified AddABConfirmatorydepositor-specified cross reference
602422Late stage assay provider assay for AddAB inhibitors: Radioactivity-based biochemical assay to identify inhibitors of the nuclease activity of purified AddAB (100 micromolar dose)Otherdepositor-specified cross reference
623916Late stage assay provider Counterscreen for AddAB inhibitors: Cell-based colony-formation assay to identify inhibitors of the viability of V66 E. coli in Hfr recombination assaysOtherdepositor-specified cross reference
623917Late stage assay provider Counterscreen for AddAB inhibitors: Cell-based colony-formation dose response assay to identify inhibitors of the viability of V66 E. coli in Hfr recombination assaysOtherdepositor-specified cross reference
623918Late stage assay provider Counterscreen for AddAB inhibitors: Cell-based colony formation assay to identify inhibitors of the recombination-promoting activity of RecBCD in V66 E. coli (dose response)Confirmatorydepositor-specified cross reference
623919Late stage assay provider Counterscreen for AddAB inhibitors: Cell-based colony formation assay to identify inhibitors of the recombination-promoting activity of RecBCD in V66 E. coli (100uM)Otherdepositor-specified cross reference
623920Late stage assay provider counterscreen for AddAB inhibitors: Radioactivity-based biochemical dose response assay to identify inhibitors of the nuclease activity of purified RecBCD enzymeConfirmatorydepositor-specified cross reference
623921Late stage assay provider counterscreen for AddAB inhibitors: Radioactivity-based biochemical assay to identify inhibitors of the nuclease activity of purified RecBCD enzyme (at 100 micromolar)Otherdepositor-specified cross reference
623922Late stage assay provider counterscreen for AddAB inhibitors: Radioactivity-based biochemical assay to identify inhibitors of the nuclease activity of purified RecBCD enzyme (at 50 micromolar)Otherdepositor-specified cross reference
623937Late stage assay provider counterscreen for AddAB inhibitors: Radioactivity-based biochemical assay to identify inhibitors of the helicase/Chi cutting activity of purified RecBCDOtherdepositor-specified cross reference
623942Late stage assay provider counterscreen for AddAB inhibitors: Radioactivity-based biochemical dose response assay to identify inhibitors of the helicase/Chi cutting activity of purified RecBCDConfirmatorydepositor-specified cross reference
623954Late stage assay provider Counterscreen for AddAB inhibitors: Cell-based colony-formation assay to identify inhibitors of recombination of E. coli transformed with p(addAB) and p(recA) (100 micromolar compound dose)Otherdepositor-specified cross reference
623956Late stage assay provider Counterscreen for AddAB inhibitors: Cell-based colony-formation assay to identify inhibitors of recombination of E. coli transformed with p(addAB) and p(recA) (20 micromolar compound dose)Otherdepositor-specified cross reference
651942Late stage results for the probe development effort to identify inhibitors of AddAB recombination protein complex: Absorbance-based bacterial cell-based dose response assay for inhibitors of AddAB recombination protein complex (ROUND 2)Confirmatorydepositor-specified cross reference
651943Late stage counterscreen results for the probe development effort to identify inhibitors of AddAB recombination protein complexes: absorbance-based bacterial cell-based dose response assay for inhibitors of bacterial viability (ROUND 2)Confirmatorydepositor-specified cross reference
651944Late stage counterscreen results for the probe development effort to identify inhibitors of AddAB recombination protein complex: absorbance-based bacterial cell-based dose response assay to identify inhibitors of RecBCD (ROUND 2)Confirmatorydepositor-specified cross reference
488942Absorbance-based bacterial cell-based high throughput confirmation assay for inhibitors of AddAB recombination protein complexScreeningsame project related to Summary assay
488955Counterscreen for AddAB inhibitors: absorbance-based high throughput cell-based assay to identify inhibitors of RecBCDScreeningsame project related to Summary assay
Description:
Source (MLPCN Center Name): The Scripps Research Institute Molecular Screening Center (SRIMSC)
Affiliation: The Scripps Research Institute, TSRI
Assay Provider: Gerald R. Smith, Fred Hutchinson Cancer Research Center
Network: Molecular Library Probe Production Centers Network (MLPCN)
Grant Proposal Number: GM031693
Grant Proposal PI: Gerald R. Smith
External Assay ID: ECOLIV3065VBLTY_INH_ABS_1536_3X%INH CSRUN

Name: Counterscreen for AddAB inhibitors: absorbance-based bacterial cell-based high throughput confirmation assay for inhibitors of bacterial viability.

Description:

Helicobacter pylori infects approximately half of the world's population and is responsible for inducing chronic gastric inflammation that can progress to gastric cancer (1). At the cellular level, Helicobacter pylori infection of the human stomach is associated with inflammation that elicits DNA damage in both bacterial and host cells (2). This DNA damage must be repaired in order for the bacteria to persist. The H. pylori AddAB helicase-exonuclease is required for DNA repair and efficient stomach colonization (3), and inhibitors of this enzyme may be useful antibacterial drugs for treating these infections. The AddAB class of enzymes is closely related to the RecBCD class of helicase-nucleases; both classes are widely distributed in bacteria but appear to be absent in eukaryotes (4). The protein complex functions in DNA repair by directing free DNA ends into the homologous recombination pathway (5). As a result, the identification of inhibitors of AddAB may be useful tools for elucidating the role of AddAB and RecBCD in bacterial recombination and as potential novel antibiotics with few off-target effects.

References:

1. Fox JG, Wang TC. Inflammation, atrophy, and gastric cancer. J Clin Invest. 2007 Jan;117(1):60-9.
2. Ernst P. Aliment Pharmacol Ther. 1999 Mar;13 Suppl 1:13-8. Review article: the role of inflammation in the pathogenesis of gastric cancer.
3. Dillingham MS, Kowalczykowski SC. RecBCD enzyme and the repair of double-stranded DNA breaks.
Microbiol Mol Biol Rev. 2008 Dec;72(4):642-71.
4. Amundsen SK, Fero J, Hansen LM, Cromie GA, Solnick JV, Smith GR, Salama NR, Helicobacter pylori AddAB helicase-nuclease and RecA promote recombination-related DNA repair and survival during stomach colonization. Mol Microbiol, 2008. 69(4): p. 994-1007.
5. Chedin F. and Kowalczykowski S.C. A novel family of regulated helicases/nucleases from Gram-positive bacteria: insights into the initiation of DNA recombination, Mol. Microbiol. 43 (2002), pp. 823-834.

Keywords:

helicase, nuclease, exonuclease, AddAB, ADDAB, AddAB complex, RecBCD enzyme, beta subunit, gamma chain, alpha chain, Escherichia coli, E. coli, bacteria, phage, DNA, dsDNA, DNA damage, DNA repair, DNA binding, ATP-binding, homologous recombination, recombination, Chi, inhibition, inhibitor, optical density, OD, absorbance, HTS, high throughput screen, counterscreen, confirmatory, confirmation, triplicate, viability, cytotoxicity, secondary, 1536, Scripps Florida, The Scripps Research Institute Molecular Screening Center, SRIMSC, Molecular Libraries Probe Production Centers Network, MLPCN.
Protocol
Assay Overview:

The purpose of this assay is to determine whether compounds identified as active in a set of previous experiments entitled, "Absorbance-based primary bacterial cell-based high throughput screening assay to identify inhibitors of AddAB recombination protein complex" (AID 435030), are nonselective inhibitors of the AddAB helicase-nuclease complex due to bacterial cytotoxicity. In this assay, V3065 bacteria are not infected with phage but, are incubated in the presence of test compounds alone, followed by measurement of well optical density as an indicator of bacterial growth. As designed, compounds that inhibit bacterial growth will reduce well absorbance. Compounds are tested in triplicate at a nominal test concentration of 11.86 uM.

Protocol Summary:

Prior to the start of the assay, V3065 bacterial culture was grown at 37 C until it reached an OD600 of 0.05 or 2.5E7 cfu/mL. V3065 was diluted in assay buffer to achieve 1.25E7 cfu/mL. To start the assay, 3 uL of Assay Buffer (0.1% Glycerol + 100 ug/mL Ampicillin + Cation Mueller Hinton Broth) was dispensed into all wells. Next, 60 nL of test compound in DMSO, Ciprofloxacin (0.95 ug/ml final concentration) or DMSO alone (1.2% final concentration) were added to the appropriate wells.

Next, 2 uL of V3065 (addAB+) bacterial culture was dispensed into the appropriate wells. Plates were incubated for 18 hours at 37 C and absorbance (OD600) was read on a Envision microplate reader (PerkinElmer, Turku, Finland) using 10 flashes per well.

The percent inhibition for each compound was calculated as follows:

100 * ( ( Test_Compound - Median_Low_Control ) / ( Median_High_Control - Median_Low_Control ) )

Where:

High_Control is defined as wells containing V3065 + Ciprofloxacin.
Low_Control is defined as wells containing V3065 + DMSO.
Test_Compound is defined as wells containing V3065 in the presence of test compound.

The average percent inhibition and standard deviation of each compound tested were calculated. In addition, two values were calculated as well: (1) the average percent inhibition of the wells containing DMSO only, and (2) eight times their standard deviation. The sum of these two values was used as a hit cutoff parameter. Any compound that exhibited a percent inhibition greater than the calculated hit cutoff was declared active.

PubChem Activity Outcome and Score:

The reported PubChem Activity Score has been normalized to 100% observed primary inhibition. Negative % inhibition values are reported as activity score zero.

The PubChem Activity Score range for active compounds is 100-24, and for inactive compounds 23-0.

List of Reagents:

V3065 E.coli bacteria (supplied by Assay Provider)
Ciprofloxacin (Sigma, part 17850)
Ampicillin (Fisher, part BP1760-5)
Cation-Adjusted Mueller Hinton II Broth (BD, part 297963)
1536-well plates (Aurora, part 19326)
Comment
Due to the increasing size of the MLPCN compound library, this assay may have been run as two or more separate campaigns, each campaign testing a unique set of compounds. All data reported were normalized on a per-plate basis. Possible artifacts of this assay can include, but are not limited to: dust or lint located in or on wells of the microtiter plate, and compounds that modulate well fluorescence. All test compound concentrations reported above and below are nominal; the specific test concentration(s) for a particular compound may vary based upon the actual sample provided by the MLSMR. The MLSMR was not able to provide all compounds selected for testing in this assay.
Result Definitions
TIDNameDescriptionHistogramTypeUnit
OutcomeThe BioAssay activity outcomeOutcome
ScoreThe BioAssay activity ranking scoreInteger
1Inhibition at 11.86 uM (11.86μM**)Normalized percent inhibition of the counterscreen at a compound concentration of 11.86 micromolar.Float%
2Standard deviationStandard deviation of the counterscreen assay derived from the normalized percent inhibition of the triplicate data for each compound.Float

** Test Concentration.
Additional Information
Grant Number: GM031693

Data Table (Concise)
Data Table ( Complete ):     View Active Data    View All Data
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