Role of dnaB43 in F'-plasmid incompatibility.

In order to perform complementation tests with mutations of DNA replication of F'-plasmids incompatibility must overcome. We report out in ability to duplicate the results presented by Palchoudhury and Iyer (1971) and Bezanson and Iyer (1975) who have claimed to demonstrate the autonomous replication two incompatible F'-plasmids in a strain carrying the temperature sensitive dna B43 allele. In addition, we describe experiments designed to measured complementation using transient heterozygotes and compatible plasmids. Assessment of our data and those of others in the light of a recent report by Uhlin and Nordström (1975) suggests that new approaches will have to be developed for the successful employment of complementation analysis in F-plasmid genetics.