Grow a 200 ml prep in superbroth to saturation by vigorous
shaking at 37ºC (6-8 hrs or overnight).
Add 200 ml more of prewarmed superbroth (to avoid shocking
cells), then add chloramphenicol to a final concentration of 125 ug/ml.
Make chloramphenicol stock solution at 125 mg/ml in ethanol,
add 1 ul per ml for final concentration of 125 ug/ml.
Chloramphenicol should be handled with care; wear gloves and
avoid inhalation of powder. Consult the MSDS sheet for further
Method 2: (modified from Maniatis, 2nd ed., p. 1.33)
Innoculate SB containing appropriate antibiotic with 4 ml of
Incubate with vigorous shaking at 37º C until the OD600 is
Add chloramphenicol to a final concentration of 170ug/ml.
Incubate for a further 12 to 16 hours at 37º C with vigorous
Note: This method only works well for 500 ml preps; for 100 ml
preps use the following modification:
Grow a 100ml prep in SB for 6 to 8 hours at 37º C in the appropriate antibiotic with vigorous shaking.
(For best results innoculate with 200ul of a 5 ml
Add chloramphenicol to 170 ug/ml final concentration and
incubate for a further 12 to 16 hours with vigorous