antibiotics concentration for JM109 and DH5 alpha - (Jun/12/2005 )

hi all..

i wanna know what are the antibiotics concentration (for kanamysin and ampicillin ) for bacterial e.coli strain JM109 and DH5 alpha so that the bacteria can grow when the plasmid got that two antibiotics. i tried to transformed the ligated plasmid that got 2 antibiotics but still dont get any colonies..plz help....

Hi,
in general we use concentrations for Ampicillin 100µg/ml
and for Kanamycin 30µg/ml.
This normally works on DH5alpha, but I have no experiences with JM109.
I never had problems with antibiotic concentration but with the ligation itself. Have you already checked if your ligation works?

hi
the gene of ampicillin confers resistance up to 100µg/ml.
For kanamycin, in our lab we use 50µg/ml. But according to me it is little strong. So i'm gonna try 30µg/ml.