Methods of plasmid transformation? only heat shock? - (Apr/19/2012 )

Is heat shock the only reliable method to introduce a plasmid into a competent cell?
I have been trying to transform a JM109 cell line with a 16kb plasmid but couldn't get it into the cell. (No Antibiotic resistant colonies were seen in my plates)

Some people have suggested using electroporation? is that done on bacterial cells or purely mammalian cells?

Electroporation is also done on bacterial cells. The conditions are quite different in terms of the pulse and the shape of the pulse, so check the conditions carefully. Read Sambrook et al. Molecular cloning: a laboratory manual, for more information.