Isolation of coliphage lambda ghosts able to adsorb onto bacterial cells.

We have examined three methods of lambda ghost production, starting with the [3H]leucine-labelled phage, purified by CsCl density gradient sedimentation. Ghosts obtained by the osmotic shock or by incubation in 5 M LiCl do not adsorb on bacteria. Ghosts obtained by the treatment with the chelating agent EDTA and purified by CsCl density gradient sedimentation possess well preserved adsorption properties and are virtually free of DNA and infectious phage particles.