Table 3 Cost comparison of clonogenic and colorimetric assays for measuring radiation sensitivity of Escherichia coli strains
From: Resazurin-based assay for screening bacteria for radiation sensitivity
Unique steps/costsa | Clonogenic (surviving fraction) | Colorimetric (resazurin) | Differential “cost” (clonogenic minus colorimetric) |
|---|---|---|---|
Reusable vessels for radiation (UV, X-ray) testing of 96 strains: | Cost for 96, 50-ml centrifuge tubes (X-ray), 96 glass Petri dishes (UV) = $465 | Cost for 2 microtiter plates = $6 (one-time use only) | $458 |
Irradiation process (strains testable/day): | 20 | 96 | Time, 5 days |
Post-irradiation incubation of cell cultures | Prepare dilution blanks using buffer and reusable glass vials = $65 (100 glass vials); time, 0.5 h | None | $65; time, 0.5 h |
Prep. of agar plates $225 (for 500 Petri dishes for plating media); time, 1 day | None | $225; time, 1 day | |
Plating of bacteria; time, 4 h | Adding media to wells; time, 1 h | Time, 3 h | |
Quantification of radiation sensitivity: | Counting colonies and calculations; time, 4 h | Read absorbance values of microtiter plate; time, 0.25 h | Time, 3.75 h |
Pipetting steps (per strain tested): | 6 | 3 | 3 pipetting steps per strain (i.e., more error) |