Isolation and characterization of motile Escherichia coli mutants resistant to bacteriophage χ

Abstract

Four mutants of E. coli that are resistant to the flagellotropic phage X, but are motile, were isolated. When they were observed in liquid culture by light microscopy, one mutant exhibited circular movement and another tumbled at high frequency on the surface of a glass slide. The remaining two mutants moved normally. None of these mutants adsorbed the wild-type strain of X. P1 transduction revealed that the mutation sites of these four mutants were more than 97% cotransducible with a site in hag, the structural gene for flagellin. When flagellins of these mutants were chromatographed on a diethylaminoethyl-cellulose column, two eluted slower and one eluted slightly faster than the flagellin of the parental strain. The other flagellin eluted at the same position as that of the parent. Host range mutants of phage X, which could infect these bacterial mutants were isolated.