NEW TYPE OF SEX FACTOR-SPECIFIC BACTERIOPHAGE OF ESCHERICHIA COLI.

Watanabe, Tsutomu (Keio University, Tokyo, Japan), and Motoyuki Okada. New type of sex factor-specific bacteriophage of Escherichia coli. J. Bacteriol. 87:727-736. 1964.-A virulent phage, W-31, isolated from sewage water, was found to have a specific relationship to the sex factor of Escherichia coli K-12; this phage formed large, clear plaques on F(-) and stable Hfr strains but small, turbid plaques on F(+) strains. Unstable Hfr strains gave intermediate-type responses to phage W-31. Further, adsorption and nucleic acid injection of phage W-31 occurred equally in F(-) and F(+) strains. In addition, a majority of F(+) cells were killed by infection with phage W-31 without producing progeny phage. These results suggest that some step(s) after nucleic acid injection is suppressed by an autonomous F but not by an integrated F. Colicinogenic factor B was also found to suppress the production of progeny of phage W-31, although colicinogenic factor E(2), prophage lambda, and R factors did not show such inhibitory effects against this phage. Colicinogenic factor B in an F(-) strain derived from an Hfr strain did not suppress the multiplication of phage W-31; this strain was further found to carry out chromosome transfer in the same order as the original Hfr strain.