Recently we have had problems with E. coli JM105 and JM109 dying at -20
C in 15% glycerol/LB. We have never had this problem with NM522 or
DH5alpha at -20 C.
Are JM105 and JM109 strains this temperature sensitive?
We store bacterial, protein, and DNA samples at both -20 C and -80 C.
We keep working glycerol cultures in the -20 C fridge and use the -80
samples for emergency back up.
gdavis at ou.edu
University of Oklahoma
Chemical Engineering and Materials Science