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Coaggregation of Porphyromonas gingivalis and Prevotella intermedia
A Kamaguch1, K Nakayama, T Ohyama
1Department of Oral Microbiology, School of Dentistry, Health Sciences University of Hokkaido, Hokkaido 061-0293, Japan.
Abstract:
Porphyromonas gingivalis cells coaggregated with Prevotella intermedia cells. The coaggregation was inhibited with L-arginine, L-lysine, Nalpha-p-tosyl-L-lysine chloromethyl ketone, trypsin inhibitor, and leupeptin. Heat- and proteinase K-treated P. gingivalis cells showed no coaggregation with P. intermedia cells, whereas heat and proteinase K treatments of P. intermedia cells did not affect the coaggregation. The vesicles from P. gingivalis culture supernatant aggregated with P. intermedia cells, and this aggregation was also inhibited by addition of L-arginine or L-lysine and by heat treatment of the vesicles. The rgpA rgpB, rgpA kgp, rgpA rgpB kgp, and rgpA kgp hagA mutants of P. gingivalis did not coaggregate with P. intermedia. On the other hand, the fimA mutant lacking the FimA fimbriae showed coaggregation with P. intermedia as well as the wild type parent. These results strongly imply that a heat-labile and proteinous factor on the cell surface of P gingivalis, most likely the gingipain-adhesin complex, is involved in coaggregation of P. gingivalis and P. intermedia.
Insights
Porphyromonas gingivalis and Prevotella intermedia coaggregation is mediated by a heat-labile factor on P. gingivalis. This interaction, likely involving the gingipain-adhesin complex, can be inhibited by specific amino acids and protease inhibitors.
Area of Science:
- Oral microbiology
- Bacterial interactions
- Periodontal disease pathogenesis
Background:
- Porphyromonas gingivalis and Prevotella intermedia are key pathogens in periodontal disease.
- Interbacterial coaggregation can influence microbial community structure and virulence.
Purpose of the Study:
- To investigate the mechanisms underlying the coaggregation between P. gingivalis and P. intermedia.
- To identify the specific factors involved in this interaction.
Main Methods:
- Coaggregation assays using wild-type and mutant strains of P. gingivalis and P. intermedia.
- Treatment of cells and vesicles with heat, proteinase K, and protease inhibitors.
- Analysis of vesicle-mediated aggregation.
Main Results:
- Coaggregation was inhibited by L-arginine, L-lysine, and protease inhibitors.
- Heat and proteinase K treatment of P. gingivalis abolished coaggregation, while treatment of P. intermedia had no effect.
- Mutants lacking rgpA, rgpB, or kgp genes involved in protease activity did not coaggregate.
- Vesicles from P. gingivalis also mediated aggregation, inhibited by L-arginine, L-lysine, and heat.
Conclusions:
- A heat-labile, proteinaceous factor on the P. gingivalis cell surface, likely the gingipain-adhesin complex, mediates coaggregation with P. intermedia.
- This interaction is distinct from fimbrial-mediated coaggregation.