Host controlled modification of the transducing activities of lambda phage.
Transducing lambdadg produced by growth in Escherichia coli C is restricted in its ability to transduce the galactose genes into E. coli K. Plaque-forming lambda grown in C is similarly restricted in providing the helper function for transduction. However, at higher multiplicities of infection restricted lambda shows cooperative effects in providing helper function (analogous to those seen in the initiation of a lytic cycle), and the helper function may equal or exceed that provided by unrestricted phage. The capacity of restricted lambda to provide helper function is greatly reduced if the infected complexes are formed during a brief period of anaerobiosis. This parallels the anaerobic effect on cooperative infection reported in earlier studies. These observations are consistent with the two-step model for the restriction of the vegetative growth of host-modified lambda.
Weinfeld
H
H
Department of Medicine C and Experimental Biology, Roswell Park Memorial Institute, Buffalo, New York, USA.
Paigen
K
K