Attempts were made to obtain recombinants between the morganocinogenic factor Mor174 and R plasmid R772 by transductional techniques. Transduction frequencies of the kanamycin resistance marker of R772 to PM5006 or Providence P29 carrying Mor174 by phages 5006M and PL25, respectively, were 1000-fold higher than to the corresponding Mor174- strains. The frequency of phage PI-mediated transduction of the same marker to J62 was high and was not affected by the presence of Mor174 in the recipient. Transduction of the kanamycin resistance marker to PM5006 yielded heterogenote-like transductants. Transduction of the same marker to PM5006 with Mor174 as resident resulted in transductants which not only yielded low frequency kanamycin resistance transducing particles on induction but could transfer Mor174 and the transduced marker independently by conjugation. It was suggested that Mor174 exerted some function in establishing a transductionally shortened R factor. Mor174 also possibly played a role in the separation of the phage component of the transducing particle from the R factor portion. The severed phage genes could then integrate in tandem to a cryptic prophage to render transductants inducible. A phage 5006M lysate of PM5006(Mor174R772) produced a cotransductant. This transductant could not, possibly due to more extensive transductional shortening, transfer markers by conjugation. Induction yielded some particles which could cotransduce the markers to PM5006(P-). With assistance of the latter conjugative plasmid, markers of Mor174 and R772 were transferred as a unit by conjugation to strain J62. Phage PI reared on the latter transconjugant cotransduced the genes for Mor174 activity and kanamycin resistance. Morganocin production by the recombinant equalled that of Mor174.


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