Related Experiment Video
Updated: Dec 11, 2025
Porphyromonas gingivalis as a Model Organism for Assessing Interaction of Anaerobic Bacteria with Host Cells
Published on: December 17, 2015
Purification of Native Mfa1 Fimbriae from Porphyromonas gingivalis
Yoshiaki Hasegawa1, Keiji Nagano2, Yukitaka Murakami3
1Department of Microbiology, School of Dentistry, Aichi Gakuin University, Nisshin, Aichi, Japan. yhase@dpc.agu.ac.jp.
Abstract:
Fimbriae of the periodontal pathogen Porphyromonas gingivalis mediate its colonization through associations with other bacteria and host tissues. P. gingivalis generally expresses two distinct fimbrial types, FimA and Mfa1. In P. gingivalis ATCC 33277, FimA fimbriae are present as long filaments easily detached from cells, whereas Mfa1 fimbriae are short filaments compactly bound to the cell surface. Because of this unique characteristic, FimA fimbriae have been selectively and easily isolated from the bacterial cell surface through mechanical shearing such as by pipetting and stirring. However, P. gingivalis ATCC 33277 harbors a mutation in the gene encode the fimbrial length regulator, FimB, and thus produces unusually long FimA fimbriae length. Hence, mechanical shearing to remove FimA is potentially applicable only for this type strain. Here we present protocols to purify intact Mfa1 fimbriae from a fimA-deficient mutant strain. Mfa1 fimbriae are purified from cell lysates, using a French pressure cell and through ion-exchange chromatography. The purity of Mfa1 fimbriae can be confirmed through sodium dodecyl sulfate-polyacrylamide gel electrophoresis, immunoblotting, and electron microscopy.
Insights
Researchers developed methods to purify Mfa1 fimbriae from Porphyromonas gingivalis. This advancement aids in studying the role of Mfa1 fimbriae in periodontal disease pathogenesis.
Area of Science:
- Microbiology
- Periodontology
- Bacterial Pathogenesis
Background:
- Porphyromonas gingivalis fimbriae, specifically FimA and Mfa1, are crucial for its colonization and association with host tissues in periodontal disease.
- The P. gingivalis ATCC 33277 strain exhibits distinct fimbrial characteristics: long, easily detached FimA and short, cell-bound Mfa1.
- Mechanical shearing is effective for isolating FimA from this specific strain due to its mutation affecting FimB, leading to unusually long FimA.
Purpose of the Study:
- To establish reliable protocols for the purification of intact Mfa1 fimbriae from P. gingivalis.
- To provide a method for obtaining pure Mfa1 fimbriae, independent of FimA, for further research.
Main Methods:
- Purification of Mfa1 fimbriae from cell lysates of a fimA-deficient P. gingivalis mutant strain.
- Utilized a French pressure cell for cell lysis and ion-exchange chromatography for purification.
- Confirmed Mfa1 fimbriae purity using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), immunoblotting, and electron microscopy.
Main Results:
- Successfully developed and presented protocols for purifying intact Mfa1 fimbriae.
- Demonstrated the effectiveness of French pressure cell lysis and ion-exchange chromatography for Mfa1 isolation.
- Confirmed the purity and integrity of the isolated Mfa1 fimbriae through multiple analytical techniques.
Conclusions:
- The presented methods enable the isolation of pure Mfa1 fimbriae from P. gingivalis.
- These protocols are essential for future studies investigating the specific functions and roles of Mfa1 fimbriae in P. gingivalis pathogenesis and host interactions.
