抗生素溶液配制

Working concentrations and stock solutions
Preparation of stock solutions

Ampicillin
Carbenicillin
GE antibiotic mix
Tetracycline
Chloramphenicol

 Supplement.

About the recalculation of recipes for the arbitrary volume:

Working concentrations and stock solutions.

• AntibioticsStock solutionWorking concentration:Strict controlWeak controlmg/ml:         μg/mldilutionμg/mldilutionAmpicillin50 (H2O*)-20oC200.4 μl/ml60-1251.2-2.5 μl/mlCarbenicillin50(H2O, 50%EtOH)-20oC200.4 μl/ml60-2001.2-4 μl/mlChloramphenicol34(EtOH, MetOH)-20oC250.7 μl/ml1705 μl/mlD-cycloserine*10(0.1M NaP pH8.0)+4oC20020 μl/ml  Gentamycin10 (H2O)-20oC151.5 μl/ml  Hygromycin B10 (H2O)-20oC101 μl/ml40040 μl/mlKanamicin50 (H2O)+4oC--20oC100.2 μl/ml501 μl/mlKasugamycin10 (H2O)-20oC1000100 μl/ml  Nalidixic acid5(H2O, pH to 11 /NaOH)-20oC153.0 μl/ml  Neomycin10 (H2O)-20oC10010 μl/ml80080 μl/mlRifampicin**34 (MetOH)-20oC1504.4 μl/ml  Spectinomycin10 (H2O)-20oC10010 μl/ml  Streptomicin50 (H2O)-20oC100.2 μl/ml501 μl/mlTetracycline***5 - 12.5(EtOH, 70%EtOH)-20oC102 μl/ml5010010 μl/ml20 μl/ml

* - Unstable solution, prepare just before use;
** - Light sensitive;
*** - Light sensitive, Mg²⁺ - inhibitor;

Preparation of stock solutions.

Ampicillin.

Conc.1ml5ml10mlAmpicillin50mg/ml50mg250mg0.5gH2O 1ml5ml10ml

• filter sterilize; or prepare from the sterile water and the sterile powder;

• store at -20^oC in small aliquots (avoid more than 10 freezing-thawing cycles);

• it is possible to use 50% glycerol instead of H₂O. The advantage - solution is liquid at -20^oC.

• some laboratories use 96% (or 50%) EtOH for ampicillin solubilization. There are two advantages in this method: (i) solution is liquid at -20^oC, (ii) the solution is self sterilizing. But the disadvantage is very serious: ethanol is a weak catalyst of ?-lactam ring disintegration. So, solution is unstable.

Carbenicillin.

Conc.1ml5ml10mlCarbenicillin50mg/ml50mg250mg0.5gH2O 1ml5ml10ml

• filter sterilize; or prepare from the sterile water and the sterile powder;

• store at -20^oC in small quantities (about 10 freezing-thawing cycles);

• 200 μg/ml for pETpfu.

GE antibiotic mix (50x).

Conc.40mlCefotaxime 25μg/ml25μg/ml1mgCeftriaxone 25μg/ml25μg/ml1mgPotassium phosphate (pH 6.0) 0.1M 40ml

• filter sterilize; or prepare from the sterile KPO₄ and the sterile powder;

• store at -20⁰C, in small quantities (about 10 freezing-thawing cycles).

Tetracycline.

Conc.1ml5ml10mlTetracycline5mg/ml5mg25mg50mgEtOH 1ml5ml10ml

• solution in EtOH, store at -20^oC;

• Mg⁺⁺- antagonist, for the selection it is necessary to use Mg-free medium.

Chloramphenicol.

Conc.1ml5ml10mlChloramphenicol34mg/ml34mg170mg340mg

• store dry powder at 4^oC, solution at -20^oC (in EtOH);

• BL21(DE3)pLyzS - 34μg/ml -> 1μl for 1ml of medium.