title: Transformation in Escherichia coli: cryogenic preservation of competent cells.
abstract: Escherichia coli cells prepared for transformation by treatment with cold 0.1 M CaCl2 remained viable and competent after storage at -82 degrees C in 15% glycerol; thawed-cell samples yielded up to 10(6) transformants per microgram of plasmid deoxyribonucleic acid.
mesh_terms: D004269:DNA, Bacterial / Q000235:genetics*; D004352:Drug Resistance, Microbial; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics*; D005615:Freezing; D005990:Glycerol; D011309:Preservation, Biological / Q000379:methods*; D013752:Tetracycline / Q000494:pharmacology; D014169:Transformation, Bacterial
chemical_list: D004269:DNA, Bacterial; D013752:Tetracycline; D005990:Glycerol