Ames 384-ISO™ Test
A high-throughput OECD 471-compliant modification of the Ames ISO fluctuation mutagenicity assay in 384-well format — designed for maximum sample throughput per run. The same proven purple-to-yellow colorimetric pH indicator endpoint as the MOD-ISO, with up to four times the capacity per plate. Completed in 2–3 days.
Request a QuoteHigh-Throughput Format — More Samples Per Run
The 384-well plate format provides up to four times the well capacity of a standard 96-well plate, enabling significantly more test concentrations, replicates, or bacterial strains to be processed in a single incubation run — ideal for screening multiple compounds or large sample sets efficiently.
The Ames 384-ISO™ Test is EBPI’s high-throughput modification of the Ames ISO fluctuation assay in 384-well microplate format, designed to meet OECD 471 Guidelines. The assay uses the same principle as the MOD-ISO: bacterial tester strains are pre-exposed to differing concentrations of the test compound in suspension for 100 minutes. After exposure, samples are transferred to a 384-well plate with a colorimetric reversion indicator solution.
Mutagenic reversion events shift the pH indicator from purple (background mutation rate / non-mutagenic) to yellow (revertant colonies present / mutagenic). The 384-well format dramatically increases sample throughput per run, making the 384-ISO ideal for multi-compound screening, multiple strain testing, or any application where volume and efficiency are priorities. Compatible with standard 384-well plate readers and automation systems.
- Test organismsSalmonella typhimurium TA98, TA100, TA1535, TA1537, TA1538, TA97a; E. coli WP2 uvrA, WP2 pkm101; YG1024, YG1028
- EndpointHis&sup0; reversion (colorimetric pH indicator): purple = background rate; yellow = revertant colonies (mutagenic)
- Format384-well microplate — up to 4× the throughput of a standard 96-well assay
- Pre-exposure100 minutes in suspension at differing concentrations
- Incubation2–3 days at 37°C
- DetectionColorimetric visual + spectrophotometric; pH indicator purple → yellow
- Metabolic activationCompatible with S9 activation; doubles reagents and plastics included
- OECD complianceOECD 471 — Bacterial Reverse Mutation Test; all required controls included
- Instrument compatibilityStandard 384-well plate readers; compatible with laboratory automation systems
📧 Order or Enquire
🍁 Ships from Burlington, Ontario, Canada · International shipping available · S9 versions available on request
384-ISO Assay Procedure
The Ames 384-ISO™ Test follows the same proven methodology as the MOD-ISO, adapted for the 384-well high-throughput format. Completed in 2–3 days.
Pre-Exposure
Bacterial tester strain pre-exposed to test compound at differing concentrations in suspension for 100 minutes at 37°C
Transfer & Plate
Samples transferred and mixed with colorimetric reversion solution; plated onto 384-well plate with replicates at multiple dilutions
Incubation
Plates incubated 2–3 days at 37°C in sealed Ziploc bags; revertant colonies grow and shift pH indicator colour
Count & Calculate
Count yellow (revertant) vs. purple (non-revertant) wells; calculate mutagenic ratio relative to background and positive controls
Fig. 1 — Ames 384-ISO™ Plate Result
The photograph below shows a typical Ames 384-ISO™ result. The purple-to-yellow pH indicator endpoint is identical to the MOD-ISO. The upper rows (A–E) show predominantly purple — the background (spontaneous) mutation rate. As the plate progresses downward through the rows, increasing yellow wells reflect the dose–response gradient, with the lower rows showing the positive mutagenic control where reversion is complete and all wells are yellow.
Reading the Plate Result
Purple — Background / Non-Mutagenic
No reversion occurred. The bacterial strain remains histidine auxotrophic. Purple wells represent the background spontaneous mutation rate (negative controls) or no mutagenic activity at the tested concentration. A small number of spontaneous purple→yellow transitions is normal and expected in control wells.
Yellow — Revertant Colonies / Mutagenic
Reversion has occurred — bacteria have mutated back to histidine prototrophy, grown, and produced acid that shifts the pH indicator to yellow. An increase in yellow wells above background indicates mutagenic activity. The positive control wells should be all yellow, confirming assay validity.
Three Kit Formats — All Available With or Without Plastics & S9
All three kits use the same 384-ISO methodology. The Basic Kit plastics are the foundation — all other kits are built from the same plastics set, scaled by the number of bacterial strains. Contact EBPI to confirm the right configuration for your regulatory requirement or throughput needs.
Ames 384-ISO™ Basic Kit
1 Ames tester strainSingle bacterial strain kit for routine high-throughput mutagenicity screening. Available with or without plastics, and with or without S9 metabolic activation.
Ordering Options
- 6041-1S — Basic Kit, no plastics, without S9
- 6041-1SP — Basic Kit, with plastics, without S9
- 6041S9-1S — Basic Kit, no plastics, with S9
- 6041S9-1SP — Basic Kit, with plastics, with S9
Reagents Include
- 1 Ames bacterial strain, growth media, and controls
- 120 mL sterile distilled water
Plastics (when ordered with plastics)
- 3 × 384-well plates
- 2 × 24-well plates
- 3 × 15 mL tubes
- Ziploc bags for incubation
Ames 384-ISO™ Bacterial Strain Kit
2 Ames tester strainsTwo bacterial strain kit for broader mutagenicity profiling. Plastics and reagents scaled from the Basic Kit to accommodate two strains run in parallel.
Ordering Options
- 6041-2BS-1S — 2-Strain Kit, no plastics, without S9
- 6041-2BS-1SP — 2-Strain Kit, with plastics, without S9
- 6041S9-2BS-1S — 2-Strain Kit, no plastics, with S9
- 6041S9-2BS-1SP — 2-Strain Kit, with plastics, with S9
Reagents Include
- 2 Ames bacterial strains, growth media, and controls
- 240 mL sterile distilled water (2 × Basic Kit)
Plastics (when ordered with plastics)
- 6 × 384-well plates (2 × Basic Kit)
- 4 × 24-well plates
- 6 × 15 mL tubes
- Ziploc bags for incubation
Ames 384-ISO™ OECD Kit
5 Ames tester strains · OECD 471Five bacterial strain kit designed to meet OECD Test Guideline 471. S9 metabolic activation is always included. Plastics and reagents scaled from the Basic Kit across all five strains.
Ordering Options
- 6041S9-OECD-1S — OECD Kit with S9, no plastics
- 6041S9-OECD-1SP — OECD Kit with S9, with plastics
ⓘ S9 metabolic activation is required for OECD 471 compliance and is included in both OECD kit configurations.
Reagents Include
- 5 Ames bacterial strains, growth media, and controls
- 600 mL sterile distilled water (5 × Basic Kit)
- All controls required for OECD 471 compliance
Plastics (when ordered with plastics)
- 15 × 384-well plates (5 × Basic Kit)
- 10 × 24-well plates
- 15 × 15 mL tubes
- Ziploc bags for incubation
Tester Strains — Standard & Specialist
EBPI stocks the standard Ames test strains plus specialist strains for enhanced detection of specific compound classes. Contact EBPI if your required strain is not listed below.
🏢 OECD 471 Compliance — What This Means for Your Submission
The Ames 384-ISO™ OECD Kit is designed to meet OECD Test Guideline 471 for the Bacterial Reverse Mutation Test. Requirements include: testing with and without metabolic activation (S9), at least 5 concentrations in replicates, appropriate positive and negative controls, and results expressed as the number of revertant colonies per plate or equivalent. All required controls are included. Contact EBPI to confirm the appropriate kit configuration for your specific regulatory submission.
⚙️ Metabolic Activation with S9 Fraction — Pro-Mutagen Detection
Many mutagenic compounds require metabolic activation by liver enzymes before they become active. The Ames 384-ISO™ is available with or without S9 metabolic activation for the Basic and Bacterial Strain kits; S9 is always included in the OECD Kit. The S9 fraction converts pro-mutagens such as benzo[a]pyrene, aflatoxin B1, 2-aminoanthracene, and aromatic amines into their active mutagenic forms. When ordered with S9, plastics and reagents are doubled to allow parallel testing with and without activation. S9 Activation Enzymes are available separately (Product No. S9-AMES).
Why Use the Ames 384-ISO™?
⚡ Maximum Throughput
384-well format delivers up to four times the capacity of a standard 96-well assay — ideal for multi-compound screening, method development, and high-volume regulatory testing programs.
🏢 OECD 471 Compliant
Designed to meet OECD Test Guideline 471 for bacterial reverse mutation testing, supporting regulatory submissions in pharmaceutical, chemical, food, and cosmetic sectors.
📉 Objective Colorimetric Readout
Purple/yellow pH indicator provides an unambiguous result readable visually or by standard 384-well plate reader. No colony counting required.
🔬 Built on Proven MOD-ISO Method
The 384-ISO uses the same validated ISO fluctuation methodology as the MOD-ISO — only the plate format changes. Laboratory staff familiar with the MOD-ISO protocol can adopt the 384-ISO immediately.
🧪 Broad Strain Availability
10 standard and specialist tester strains available covering frameshift, base-pair substitution, and specific compound classes. Additional strains on request from EBPI.
🧬 Automation Compatible
384-well format is compatible with standard laboratory liquid handling and plate reader automation systems, enabling efficient high-throughput workflows.
Applications for the Ames 384-ISO™ Test
High-Throughput Chemical Screening
Screen large chemical libraries or multiple compound concentrations in a single run — maximising information per plate and reducing total assay time.
Pharmaceuticals & Drug Discovery
ICH S2(R1)-aligned mutagenicity screening during drug development; high-throughput screening of compound series and active pharmaceutical ingredients (APIs).
Environmental Samples
Water, wastewater, sediment extract, and air extract mutagenicity — high sample throughput makes the 384-ISO ideal for routine monitoring programs.
Food, Cosmetics & Agrochemicals
Mutagenicity screening of food additives, cosmetic ingredients, packaging extracts, and pesticide active substances — multiple samples per plate.
Multi-Strain Comparative Studies
Run multiple bacterial strains simultaneously on a single plate, enabling efficient strain-by-strain comparison of mutagenic response for a given compound.
Research & Method Development
The high-capacity format is ideal for dose–response characterisation, inter-laboratory validation studies, and academic mutagenicity research programs.
Kit Specifications
| Parameter | Detail |
|---|---|
| Product Numbers |
Basic Kit: 6041-1S · 6041-1SP · 6041S9-1S · 6041S9-1SP Bacterial Strain Kit: 6041-2BS-1S · 6041-2BS-1SP · 6041S9-2BS-1S · 6041S9-2BS-1SP OECD Kit (S9 always included): 6041S9-OECD-1S · 6041S9-OECD-1SP (5 strains) |
| Test Method | Modification of Ames ISO fluctuation assay; 384-well microplate colorimetric format |
| Pre-Exposure | 100 minutes in suspension at varying concentrations |
| Endpoint | His&sup0; → His¹ reversion detected by pH indicator: purple = non-revertant; yellow = revertant (mutagenic) |
| Incubation | 2–3 days at 37°C |
| Plate Format | 384-well microplate — up to 4× throughput of 96-well format |
| Basic Kit Plastics | 3 × 384-well plates; 2 × 24-well plates; 3 × 15 mL tubes; Ziploc bags |
| Basic Kit Water | 120 mL sterile distilled water (per strain; multiplied by number of strains) |
| Standard Tester Strains | TA98, TA100, TA1535, TA1537, TA1538, TA97a, WP2 uvrA, WP2 pkm101, YG1024, YG1028 |
| Metabolic Activation | +/− S9 available for Basic and Bacterial Strain kits; S9 always included in OECD Kit |
| Regulatory Compliance | OECD 471 — Bacterial Reverse Mutation Test (OECD kit versions) |
| Instrument Compatibility | Standard 384-well plate readers; compatible with laboratory automation systems |
| Detection | Visual colorimetric (purple/yellow) or spectrophotometric 384-well plate reader |
| Manufacturer | EBPI — Environmental Bio-Detection Products Inc., Burlington ON, Canada |
Technical Resources
Excel Worksheet
EBPI’s data recording and mutagenic ratio calculation worksheet for the 384-ISO
⬇️ Download PDFOther Mutagenicity & Genotoxicity Tests
Contact EBPI for pricing, strain selection guidance, OECD version details, or S9 activation options for the Ames 384-ISO™ Test.