Pili of Aeromonas hydrophila: purification, characterization, and biological role

Microbiol Immunol. 1990;34(2):83-98. doi: 10.1111/j.1348-0421.1990.tb00995.x.


Aeromonas hydrophila (Ae6) has 2 morphologically distinctive kinds of pili. One appeared rigid, channeled, and straight with a diameter of 9 nm (Ae6-R pili). The other looked flexible, wavy, and having helical structure with a diameter of 7 nm (Ae6-W pili). Ae6-R pili were purified and characterized. The pili consisted of a subunit protein with a molecular weight of 18 kDa as estimated by SDS-PAGE, and contained 42.3% hydrophobic amino acids and one cysteine residue. The pilus was solubilized to 18 kDa subunit protein by 2-mercaptoethanol, dithiothreitol, hydrochloric acid, or heating at 120 C for 5 min. The organism Ae6 was strongly adhesive to rabbit intestines as well as human intestines, and agglutinated erythrocytes. Anti-pili antibody (Fab fraction) did not block the adhesion. Purified Ae6-R pili did not adhere to the intestine or to the erythrocytes. However, the anti-pili Fab inhibited pellicle formation of the organisms cultured in broth, and also inhibited salt agglutination with ammonium sulfate. From these results, Ae6-R pili are not likely a colonization factor but probably play a role in the autoaggregation of the organisms.

MeSH terms

  • Aeromonas / physiology
  • Aeromonas / ultrastructure*
  • Amino Acids / analysis
  • Animals
  • Antibodies, Bacterial / immunology
  • Bacterial Adhesion
  • Blotting, Western
  • Feces / microbiology
  • Fimbriae, Bacterial / physiology
  • Fimbriae, Bacterial / ultrastructure*
  • Hemagglutination
  • Humans
  • Intestines / microbiology
  • Intestines / physiology
  • Microscopy, Electron, Scanning
  • Rabbits


  • Amino Acids
  • Antibodies, Bacterial