To 2mls of mid-log culture or 1ml of freshly saturated culture add 1ml(or an equal volume) of glycerol solution, mix gently, then freeze rapidly in liquid nitrogen or on dry ice. Store at -20°C and - 70°C. - [Read Bacterial Glycerol Stocks Protocol]
4 strains of E. coli are used in these studies: JM101 for M13 infection and isolation, XL1BMRF'for M13 or pUC-based DNA transformation, and ED8767 for cosmid DNA transformation. To maintain their respective F' episomes necessary for M13 viral infection, JM101 is streaked onto a M9 minimal media plate and XL1BMRF' is streaked onto an LB plate containing tetracycline. ED8767 is streaked onto an LB plate. These plates are incubated at 37degC overnight. For each strain, 3 ml. of appropriate liquid.. - [Read Bacterial Cell Maintenance Protocol]
Plasmid (pUC series) containing genomic DNA fragments are maintained in E. coli strain DH5aTM. The E. coli cultures are routinely cultured at 37 C on Luria-Bertani (LB) agar on or in LB broth containing Ampicillin (30 µg/ml) or Carbenicillin (50 µg/ml broth, 100 µg/ml agar). E. coli strains are usually preserved in stab agar or glycerol for mid-term storage and lyophilized for long-term storage. - [Read Maintenance of Probes in Bacteria Including Escherichia coli Protocol]