---+++ Protocol For Determining Mutation Rates to Antibiotic Resistance ---++++ Day -2: Prepare Media / Revive Prepare 100 LB-agar plates with the antibiotic to be tested and 13 LB-agar plates with no antibiotic. This requires about 2 L of media. Start a 10 ml culture in rich media from ice scraped from the top of a freezer stock of the bacterial strain to be tested. Grow 16-24 hours at 37°C. ---++++ Day -1: Precondition Transfer an appropriate dilution of the overnight starter culture to the 10 ml of the medium that will be used during the fluctuation test. At least 100-fold growth should occur during this preconditioning step. Grow 16-24 hours at 37°C. ---++++ Day 0: Growth of Independent Cultures Prepare a 96-well plate. Reserve well A1 for a blank (no cells added). Innoculate the remaining 95 wells with approximately 10<sup>3</sup> cells in the growth medium. Grow microplate exactly 24 hours at 37°C. ---++++ Day 1: Plating of Independent Cultures Plate the entire volume (now slightly less than 200 µl) from 86 of the 96 wells onto LB-antibiotic plates. Make an appropriate dilution of the remaining 9 wells to count the number of viable cells. ---++++ Day 2: Counting Plates Streak out any questionable colonies on the remaining antibiotic plates to verify that they are resistant. Also streak out any colonies that you might want to save. -- Main.JeffreyBarrick - 18 Sep 2007
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Topic revision: r1 - 2007-09-18 - JeffreyBarrick