[Penetration of exogenous DNA through the membranes of Escherichia coli treated with Ca2+ cations].

Possible role of electrochemical potential as driving force for exogenous DNA penetration inside Ca2+ treated Escherichia coli was investigated using carbonyl-cyanide-m-chlorophenylhydrasone (CCCP), an uncoupler of oxidative phosphorylation. CCCP at concentrations of 10(-6) -10(-5) M did not affect the number of plague forming units. The inhibitory effect was observed under higher concentrations (5.10(-5) -10(-4). This effect was not due to the loss of cell viability and is attributed to the reduced capacity of the cells to interact with DNA. It is suggested that conformational changes in biomembranes might be at least partially involved. It is concluded that the electrochemical potential is not the driving force for penetration of exogenous DNA inside Ca2+ -treated E. coli cells. Bronian movement is suggest as an alternative.