RT Journal Article SR Electronic(1) A1 Lawn, A. M.YR 1966 T1 Morphological Features of the Pili Associated with Escherichia coliK12 Carrying R Factors or the F Factor JF Microbiology, VO 45 IS 2 SP 377 OP 383 DO https://doi.org/10.1099/00221287-45-2-377 PB Microbiology Society, SN 1465-2080, AB SUMMARY: Strains of Escherichia coli K12 carrying various R factors or the F factor were examined with the electron microscope. The F specific RNA phage MS 2 was added to differentiate the specific F type pili, which adsorbed the phage, from common pili, which did not. Even when phage was not added it was possible to identify F type pili because they were wider and generally longer than common pili. F type pili, but never common pili, often possessed terminal knobs whose presence on attached pili has not been previously described. The F type pili formed by E. coli carrying the different R factors or HfrH could not be morphologically distinguished from each other. Only one morphological type of common pilus was observed., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-45-2-377