Identification by heteroduplex analysis of an invertible element (Min) common among IncM group plasmids

Abstract
The analysis of heteroduplexes between EcoRI digested DNA derived from IncM plasmids in the transfer‐off and in the transfer‐on state revealed an internal loop of about 1 kbp on a distinct large EcoRI fragment. The presence of an invertible element (Min) is suggested which enables the formation of conjugative piliat 30 °C, but switches off the pilus formation at 37 °C incubation temperature.