RT Journal Article SR Electronic(1) A1 Farnsworth, P. A. A1 James, R.YR 1972 T1 An Effect of the Ion Phenotype in Escherichia coli as Indicated by the Growth of Amoebae of Dictyostelium discoideum JF Microbiology, VO 73 IS 3 SP 447 OP 454 DO https://doi.org/10.1099/00221287-73-3-447 PB Microbiology Society, SN 1465-2080, AB SUMMARY: A correlation has been observed in strains of Escherichia coli between the Ion phenotype and the capacity to support the growth of Dictyostelium discoideum amoebae. lon + strains, E. coli B/r Ion sul and E. coli K12 lon + strain, when used as the food source, yielded approximately four times the number of amoebae as the Ion- strains, E. coli B and E. coli K-12 AB1899. The differences in yield may be caused by the release of an extracellular inhibitor of the growth of slime-mould amoebae by the Ion strains. Interaction with this Ion phenotype effect was observed with the DNA repair mutants exrA, recA or uvr. The effect of the inhibitor release on the yield of amoebae in E. coli B or E. coli Bs-2 was partially modified by conjugation into these strains of the sex factor F' lon +. Reduced ability to support growth of slime-mould amoebae and high sensitivity to the antibacterial agent crystal violet appear to be properties specific to filamentous lon- strains. Two possible sites in the bacteria are suggested which may be involved in expression of the Ion phenotype., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-73-3-447