A plasmid in Legionella pneumophila

Abstract
From the 6 serogroups of L. pneumophila 16 strains were examined for the presence of extrachromosomal genetic elements by a modified cleared lysate procedure, dye-buoyant centrifugation and agarose gel electrophoresis. Two strains, Atlanta-1 and Atlanta-2 from serogroup II each contained a plasmid of cryptic function with a MW of approximately 30 Mdaltons.