title: Transformation and preservation of competent bacterial cells by freezing.
mesh_terms: D002118:Calcium / Q000494:pharmacology; D002463:Cell Membrane Permeability / Q000187:drug effects; D003001:Cloning, Molecular / Q000379:methods; D004926:Escherichia coli / Q000235:genetics*; D005615:Freezing; D005990:Glycerol; D011309:Preservation, Biological; D014170:Transformation, Genetic
chemical_list: D005990:Glycerol; D002118:Calcium