The exploitation of lambda tra transducing phages in the study of bacterial conjugation

A set of lambda tra transducing phages have been isolated from an abnormal lysogen in which the lambda prophage was inserted into the traB gene of Flac, and characterised both genetically and physicochemically. The phages were used in several ways to facilitate studies of bacterial conjugation: (a) they aided the identification and mapping of four new transfer genes, traU, traN, traV and traW: (b) they gave information about the location and orientation of the promoters for traM, traJ and traI: (c) a more precise physical map of the transfer region was developed from the lengths of the tra segments that they carried, and (d) the molecular weights of the traM and traJ proteins synthesised by a lambda ptraMJALEK phage were determined.