title: Proton conductor vs. cold in induction of Ca(2+)-dependent competence in Escherichia coli.
abstract: In order to elucidate the molecular mechanisms of Ca(2+)-dependent competence in gram-negative bacteria an attempt was made to induce the competence at room temperature in presence of a proton conductor, carbonylcyanide-m-chlorophenylhydrazone (CCCP). Escherichia coli K12 cells treated with Ca2+ at 25 degrees or 37 degrees C in presence of CCCP became permeable for transforming plasmid and transfecting DNAs and DNA-binding antibiotic actinomycin C (AmC) and rubomycin (Rm) at room temperature. The efficiencies of transformation and transfection, however, were by 1-3 orders of magnitude lower compared to cells, treated with Ca2+ at 0 degree C, though both recipients did not differ significantly in their susceptibility to AmC and Rm. Possible mechanisms of Ca2+ action in both recipient systems are discussed in terms of molecular interactions.
mesh_terms: D002118:Calcium / Q000494:pharmacology*; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology*; D003080:Cold Temperature; D004269:DNA, Bacterial / Q000235:genetics; D004352:Drug Resistance, Microbial; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics; D010085:Oxidative Phosphorylation / Q000187:drug effects; D010539:Permeability; D011522:Protons; D014169:Transformation, Bacterial / Q000187:drug effects*; D014475:Uncoupling Agents / Q000494:pharmacology*
chemical_list: D004269:DNA, Bacterial; D011522:Protons; D014475:Uncoupling Agents; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D002118:Calcium