[Energy supply for transport of plasmid R 100-1 during conjugation of Escherichia coli cells]

It was shown that the transfer of plasmid R 100-1 during conjugation of donor and recipient cells of E. coli is suppressed under treatment of the cells by oxidative phosphorylation uncouplers. Studies on recipient cells devoid of their H+-ATPase activity due to mutation showed that the transfer of the plasmid into the cells is repressed after a switch-off of the respiratory chain, the only generator of proton motive force in the mutated cells. In the absence of arsenate the plasmid transfer from the donor into the recipient cells possessing intact H+-ATPase occurs independently of inhibition of the cell respiratory activity by cyanide. However, the presence of arsenate in the conjugation medium induces the sensitivity of the plasmid transfer process to cyanide. In the absence of cyanide the cell conjugation is suppressed by 60 mM arsenate. A kinetic study of different steps of cell conjugation showed that the generation of proton motive force in recipient cells is necessary for the occurrence of plasmid transport. It was assumed that the generation of both proton motive force and phosphorylated high energy compounds is a necessary prerequisite for plasmid transport during conjugation of donor and recipient cells.