Summary
Colicin factor ColIb-P9 is known to act as a sex factor in E. coli or Salmonella. Although ColIb-P9 confers mating ability on its host bacteria, this ability appears to be repressed since only a small proportion of cells in a culture of a colicinogenic strain are able to pair with, and transmit the factor to recipient bacteria. We have isolated mutants of ColIb-P9 which confer constitutive donor ability on their host. De-repression in these mutants is probably due to failure to produce repressor, rather than to insensitivity to repressor. As the colicin production by the mutants is still repressed, colicin synthesis and conjugation ability are subject to independent systems of regulation.
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Communicated by G. Bertani
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Ohki, M., Ozeki, H. Isolation of conjugation-constitutive mutants of colicin factor Ib. Molec. Gen. Genet. 103, 37–41 (1968). https://doi.org/10.1007/BF00271155
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DOI: https://doi.org/10.1007/BF00271155