FIG 5.

(a) Schematic view of the genetic constitution of plasmids. A nonmobilizable plasmid typically encodes just the origin of vegetative replication (OriV), and the mobilizable plasmid encodes the origin of transfer (OriT) along with relaxase and possibly type IV coupling protein (T4CP). The conjugative plasmid (also called self-transmissible) codes for the type IV secretion system (T4SS) in addition to the above. The nonmobilizable plasmid relies on transformation or transduction for propagation whereas the mobilizable and conjugative plasmids can be propagated via conjugation. The latter process involves relaxase-based cleaving of the plasmid at OriT, followed by interactions with T4CP and T4SS which enable pumping of DNA into the recipient cell. Plasmid types are as described in reference 36. (b) Mobility of circular plasmids from samples F and G depicted as a percentage of the total circular plasmids in that sample.