Factors affecting the release of folded chromosomes from Escherichia coli.

1. The envelope-bound folded chromosome prepared by gentle lysis of Escherichia coli K 12 DG 75 cells in the presence of 1.0 M sodium chloride was found to be a non-specific complex of DNA strands entangled in vesicle-like envelope structures. This envelope remnant is still more or less rod-shaped. 2. Both the envelope-bound and the envelope-free folded chromosomes arise directly from intact cells. Even under extreme conditions of lysis, envelope-bound chromosomes cannot be converted into envelope-free nucleoids.