Media Amendment Stock Solutions

Reagent Abb Stock Conc. Working Conc. Dilution Solvent MSDS Notes
Ampicillin Amp 100 mg/ml 100 µg/ml 1,000× ddH2O link
3′azido-2′,3′-dideoxythymidine AZT 10 mg/ml 200 µg/ml 50× ddH2O link Soluble up to 20 mg/ml in ddH2O
bromo-chloro-indolyl-galactopyranoside X-gal 40 mg/ml 80 µg/ml 500× Dimethylformamide (DMF) link X-gal is a histochemical substrate for β-galactosidase which cleaves X-Gal to yield an insoluble blue precipitate.
Carbenicillin Crb 100 mg/ml 100 ug/ml 1,000× 50% ETOH link
Chloramphenicol Cam 20 mg/ml 20 µg/ml 1,000× EtOH link  
Cycloheximide Chx 50 mg/ml 50 µg/ml 1,000× ddH2O or MeOH link anti-fungal, highly toxic
D-cycloserine Dcs 4 mg/ml 4 ug/ml 1,000× ddH2O link Degrades noticeably over the course of 1 week at 4C
Gentamycin Gen 5 mg/ml 5 µg/ml 1,000× ddH2O link  
Kanamycin Kan 50 mg/ml 50 µg/ml 1,000× ddH2O link plates lose sensitivity after 2 weeks
Nalidixic Acid Nal 30 mg/ml 30 µg/ml 1,000× 1 M NaOH link  
Novobiocin Nov 200 mg/ml 200 µg/ml 1,000× ddH2O link  
Rifampicin Rif 50 mg/ml 100 µg/ml 500× MeOH + drops of 10 M NaOH link highly toxic
Spectinomycin Spec 60 mg/ml 60 µg/ml 1,000× ddH2O link  
Streptomycin Str 100 mg/ml 100 µg/ml 1,000× ddH2O link  
Tetracycline Tet 10 mg/ml 10 µg/ml 1,000× 70 % EtOH link light sensitive, stability < 2 weeks
Zeocin Zeo 10 mg/ml 10 µg/ml 1,000× ddH2O link Some labs report using a higher concentration for selection. 10 µg/ml is specifically used for growth of amberless strain A37
Working concentrations are for liquid or solid media.

Preparation

Generally, prepare 30-50 ml of solution in a 50 ml conical tube. Then, filter sterilize solutions by pushing them through a 50 ml syringe fitted with a 0.22 µm filter made of a material appropriate for the solvent. Aliquot into 1.5 ml portions in 1.7 ml tubes using the repeat pipettor. Label with a permanent marker (one that won't wash off with ethanol). Store at -20°C in the dark.

Other considerations

Rifampicin is light-sensitive and degrades in solution rather quickly, needs to be stored wrapped in foil and replaced every 2 months.

Ampicillin degrades quickly in both plates and stock solutions. Culture plates with amp can be stored at 4C for about 2 weeks. Stock solutions can be stored at 4C for 2 weeks but can last as long as 4-6 months when stored at -20C.

D-cycloserine is best used within two days of pouring. A single small-scale experiment found 6-10x as many E. coli colonies on 8-day old MG-Dcs plates that had spent 3 of those days at 20C and 5 at 4C, compared to what was found on 1 day old MG-Dcs.

Kanamycin plates only last a few weeks at 4 C; best to make fresh kan plates every 2 weeks.

Antibiotic (Chemical Form) Abb MW Stock Conc. Volume Mass Solvent Notes
Chloramphenicol Cam 323.13 20 mg/ml 50 ml 1.00 g EtOH  

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This topic: Lab > WebHome > ProtocolList > ProtocolsGeneGorgingMarker > ProtocolsAntibioticStockSolutions
Topic revision: r32 - 2014-07-02 - SeanLeonard