CHARACTERIZATION OF AN HFR STRAIN OF SHIGELLA FLEXNERI.

Schneider, Herman (Walter Reed Army Institute of Research, Washington, D.C.), and Stanley Falkow. Characterization of an Hfr strain of Shigella flexneri. J. Bacteriol. 88:682-689. 1964.-A Hfr Shigella flexneri, strain 69, was obtained by terminal marker selection in a cross between Hfr Escherichia coli and S. flexneri. The chromosome of this Hfr Shigella bears gross homology to the E. coli chromosome: it can conjugate with both Shigella and E. coli; its order of gene transmission is the same as E. coli; and interrupted matings show that distance between gene loci is the same as for E. coli. The kinetics of transfer of the pro(+), thr(+) + leu(+), and arg(+) loci by Hfr S. flexneri differ from Hfr E. coli, and may indicate that function of the sex factor, F, derived from E. coli, is modified when integrated into the Shigella chromosome.