title: Repression of the virulence of Yersinia pestis by an F' plasmid.
abstract: An F-lac plasmid from Escherichia coli was transferred to virulent Yersinia pestis, resulting in the repression of virulence. The Y. pestis F-lac clones retained all of the known virulence traits but were avirulent and calcium independent. Every lac segregant derived from the F-lac clones was fully virulent and calcium dependent.
mesh_terms: D002118:Calcium / Q000494:pharmacology; D003227:Conjugation, Genetic; D005144:F Factor; D007785:Lactose / Q000378:metabolism; D015010:Yersinia pestis / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity*
chemical_list: D007785:Lactose; D002118:Calcium