title: [Quantity of compentent cells in a population of Escherichia coli treated with Ca2+ cations].
abstract: An attempt was made to estimate the number of Escherichia coli K-12 cells rendered permeable to antibiotics under Ca2+ treatment. The effect of cold factor and Ca2+ alone as well as the cell age on the induction of permeability and the energy dependence of the latter were also investigated. About 70-75% and more exponentially growing cells as a result of Ca2+ treatment became sensitive to actinomycin, rubomycin and olivomycin. This number was somewhat lower (40-50%) in sationary phase culture. A fraction (20-30%) of stationary phase cells appeared to be sensitive to antibiotics even without Ca2+ pretreatment. Preincubation of the cells in cold in the absence of Ca2+ cations did not induce the cell permeability. The transport of antibiotics inside the cell was not prevented by an uncoupler of oxidative phosphorylation --carbonylcyanid-m-chlorophenylhydrazone (CCCP). It is suggested that the cells which are rendered permeable to tested antibiotics represent the "compentent" cells capable to uptake molecules of exogenous DNA as well.
mesh_terms: D000900:Anti-Bacterial Agents / Q000378:metabolism / Q000494:pharmacology*; D001692:Biological Transport / Q000187:drug effects; D002118:Calcium / Q000494:pharmacology*; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology; D002463:Cell Membrane Permeability / Q000187:drug effects; D003609:Dactinomycin / Q000494:pharmacology; D003630:Daunorubicin / Q000494:pharmacology; D004347:Drug Interactions; D004926:Escherichia coli / Q000187:drug effects*; D009848:Olivomycins / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D003609:Dactinomycin; D009848:Olivomycins; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D002118:Calcium; D003630:Daunorubicin
vernacular_title: O kolichestve kompetentnykh kletok v populiatsii Escherichia coli, obrabotannykh kationami Ca2+.