Antibiotic stocks and working concentrations
The following antibiotics can be used for selection at these concentrations in many Streptomyces sp. (If working with a new species, you should always first check whether it has intrinsic resistance to an antibiotic before attempting to use it. Generally speaking, apramycin and hygromycin are likely to be more useful as selective markers than e.g. kanamycin and carbenicillin.)
|Antibiotic||Stock [mg/ml]||Final concentration [µg /ml]|
|Apramycin||100 in dH2O||50|
|Carbenicillin1||100 in dH2O||100|
|Chloramphenicol||25 in 100% EtOH||25|
|Cycloheximide2||25 in 100% EtOH||25|
|Hygromycin3||50 in dH2O||100|
|Kanamycin||50 in dH2O||50|
|Nalidixic acid||25 in 0.2N NaOH||25|
|Thiostrepton||50 in 100% DMSO||50|
1Carbenicillin is more stable than ampicillin, but care should still be taken to avoid excessive freeze/thaw cycles which could result in degradation of the antibiotic.
2Cycloheximide is toxic, prepare the solution in a fume hood and take care when handling
3Hygromycin selection is salt-sensitive; on low-salt media such as DNA, 50 µg /ml (final concentration) is sufficient for selection.