Liphardt: Antibiotics

Antibiotic	Typical Concentration	Store At	Good For	Molecular Cloning*	Stock	Stock Storage	Notes
Ampicillin (Amp)	50 ug/mL	4°C	2 months	20 ug/mL stringent 50 ug/mL relaxed	50 mg/mL (1000x) in H2O	-20°C	Dissolve Na salt, not free base!
Kanamycin (Km)	50 ug/mL	4°C	4-6 weeks	10 ug/mL stringent 50 ug/mL relaxed	50 mg/mL (1000x) in H2O	-20°C
Chloramphenicol (Cm)	25 ug/mL	4°C	at least 1 month	25 ug/mL stringent 170 ug/mL relaxed	25 mg/mL (1000x) in EtOH	-20°C
Penicillin (Pen)	1000 ug/mL	4°C	unknown		100 mg/mL (1000x) in H2O	-20°C	This concentration is for 1 hr lysis
Tetracycline (Tet)	30 ug/mL	4°C	unknown	10 ug/mL stringent 50 ug/mL relaxed	5 mg/mL (167x) in EtOH	-20°C	This concentration is for Unc knockouts
Streptomycin (Str)	10 ug/mL	4°C	unknown	10 ug/mL stringent 50 ug/mL relaxed	10 mg/mL (1000x) in H2O	-20°C

Notes

All stocks solutions should be filter sterilized, not autoclaved!
Stocks dissolved in EtOH do not need to be filtered
All stocks should be stored at -20°
All plates and media with antibiotics should be stored at 4°
γ/δ means g/L or mg/mL
Dry antibiotic powders should be stored at 4° in a humidity-free container

• Molecular Cloning appendix A2.6 (Vol 3)