Structural rearrangements of the plasmid R68,45 in cells of Brucella suis

The mobilizing activity of the plasmid R68,45 in Escherichia coli and Brucella abortus has been studied. The plasmid R68,45 has been found to lose its ability to mobilize the chromosome in Brucella suis cells. The experiments on the conjugational transfer of R68,45 were confirmed by restriction analysis of the plasmid DNA. R68,45 has been shown to lose Cma in brucella cells via deletion. The molecular mechanisms of deletion process in brucella and other bacteria are discussed.