title: Cloning of the PacB-Ter region from plasmid Mip233 (IncHI3) and their expression in E. coli ton, tol mutants.
abstract: A region of the plasmid Mip233 (incompatibility group HI3) encoding the phenotypes of resistance to the channel-forming colicins (character PacB) and potassium tellurite (Ter), was cloned and studied. Both properties are contained in an insert of 2.2 Kbp, being the smallest functional clone (pB22) isolated so far. E. coli DH5 alpha pB22 transformants exhibit resistance to the colicins as well as to high levels of tellurite (> 1000 micrograms ml-1). Results suggest that they are genetically linked forming an inducible operon. pB22 does not show significant homology with DNA from other H plasmids. Tests using E. coli ton and tol mutants harbouring recombinant pB22 indicate that the product of gene tolC, but not that of tonB, is required for the expression of the PacB and Ter phenotypes.
authors.affiliation: Instituto de Biología Experimental, Facultad de Ciencias, Universidad Central de Venezuela, Caracas.
authors.forename: G
authors.initials: G
authors.lastname: Vílchez
authors.forename: G
authors.initials: G
authors.lastname: Alonso
authors.forename: V
authors.initials: V
authors.lastname: Rodríguez Lemoine
mesh_terms: D001692:Biological Transport / Q000235:genetics; D003001:Cloning, Molecular; D003087:Colicins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D004352:Drug Resistance, Microbial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics*; D009154:Mutation; D010641:Phenotype; D010957:Plasmids / Q000096:biosynthesis / Q000235:genetics*; D013691:Tellurium / Q000378:metabolism / Q000494:pharmacology*
chemical_list: D003087:Colicins; D013691:Tellurium