Cloning, mapping and conjugal mobility of pLPG36, a common plasmid from Legionella pneumophila serogroup-1

A plasmid designated pLPG36 was isolated from the naturally occurring Legionella pneumophila serogroup-1 and purified by CsCl buoyant density centrifugation. A restriction map of this 58 kb plasmid was constructed and provided the basis for cloning four BamHI fragments into the unique BamHI site of pUC18. The four recombinant plasmids were investigated for the mobilization function in Escherichia coli strains. Only one of these, pFLJ2, was mobilized by the IncP plasmids RP4, pRK231 and R702, but not by plasmids pSa, R40a, R387, pN3 or R16. The derivative plasmid pFLJ2 was mobilized more efficiently by R702 than by RP4 or pRK231. By genetic and deletion analysis, the mobilization region of pLPG36 was located to a 6 kb EcoRI fragment of the plasmid.