title: Derepressed plasmids of incompatibility group I1 determine two different morphological forms of pilus.
mesh_terms: D003090:Coliphages / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics* / Q000648:ultrastructure; D010861:Fimbriae, Bacterial / Q000648:ultrastructure*; D008854:Microscopy, Electron; D010957:Plasmids