Porphyromonas gingivalis is a major pathogen in destructive periodontal disease in humans. Detection and quantification of this microorganism are relevant for diagnosis and treatment planning. The prevalence and quantity of P. gingivalis in subgingival plaque samples of periodontitis patients were determined by anaerobic culture and real-time PCR amplification of the 16S small-subunit rRNA gene...

Porphyromonas gingivalis fimbriae are classified into six types (types I to V and Ib) based on the fimA genes encoding FimA (a subunit of fimbriae), and they play a critical role in bacterial interactions with host tissues. In this study, we compared the efficiencies of P. gingivalis strains with distinct types of fimbriae for invasion of epithelial cells and for degradation of cellular focal a...

UNLABELLED Porphyromonas gingivalis is a Gram-negative anaerobe that resides exclusively in the human oral cavity. Long-term colonization by P. gingivalis requires the bacteria to evade host immune responses while adapting to the changing host physiology and alterations in the composition of the oral microflora. The genetic diversity of P. gingivalis appears to reflect the variability of its ha...

Porphyromonas gingivalis is a low-abundance oral anaerobic bacterium implicated in periodontitis, a polymicrobial inflammatory disease, and the associated systemic conditions. However, the mechanism by which P. gingivalis contributes to inflammation and disease has remained elusive. Here we show that P. gingivalis, at very low colonization levels, triggers changes to the amount and composition ...

Although Porphyromonas gingivalis is known to utilize peptides preferentially, instead of free amino acids, as the source of energy and cell material, there is only limited information on what sizes and kinds of peptide this bacterium preferentially utilizes. In this study, therefore, we tested aspartate or glutamate monopolymers consisting of from 2 to 100 amino acids as metabolic substrates f...

Periodontitis is a widespread disease that appears to be due to a specific bacterial infection. Several species of bacteria have been investigated as potential pathogens, and particularly strong evidence links the presence of Porphyromonas gingivalis with indicators of periodontitis. Information concerning the transmission of P. gingivalis between human contacts may be important in determining ...

Porphyromonas gingivalis (P. gingivalis), a gram-negative anaerobe, is involved in the pathogenesis of periodontal disease, and is found frequently in the subgingival flora in patients with periodontitis. This organism possesses a variety of virulence factors including lipopolysaccharide, capsular material, fimbriae and proteases (enzymes). Among the P. gingivalis antigens, enzymes such as Argi...

The first pathogenic mechanism of Porphyromonas gingivalis, which is mainly responsible for adult periodontal diseases, is the attachment of fimbriae appendages to oral epithelial cells. The ability of a subinhibitory concentration of azithromycin to inhibit the expression of fimbriae in various strains of P. gingivalis isolated was investigated. A one-eighth subinhibitory concentration of azit...

Although hemin is an essential nutrient for the black-pigmented oral bacterium Porphyromonas gingivalis, the mechanisms involved in hemin binding and uptake are poorly defined. In this study, we have examined the binding of hemin and Congo red (CR) to P. gingivalis whole cells and have defined the conditions for maximal binding. Additionally, the accumulation of hemin by P. gingivalis under gro...

Porphyromonas gingivalis produces proteases capable of degrading cytokines, host heme proteins and some antimicrobial peptides. In this study, we show that P. gingivalis culture supernatants fully or partially degrade human neutrophil peptide alpha-defensins and human beta-defensins after 30 min. This observation suggests that proteases from P. gingivalis degrade defensins and this activity cou...