Inhibitory Effect of Human Plasma and Saliva on Co-aggregation Between Bacteroides gingivalis and Streptococcus mitis

Abstract

The effect of human plasma and saliva on co-aggregation between Bacteroides gingivalis and Streptococcus mitis was studied by means of a turbidimetric assay. The co-aggregation activity was obtained from the maximum slope of the absorbance vs. time curve. Its dependence on pH, temperature, and ionic strength was examined, and the number of Bacteroides cells in relation to the number of Streptococcus cells resulting in optimal co-aggregation was established. Co-aggregation inhibition experiments showed that the co-aggregation activity was inhibited by l-arginine and l-lysine, although the activity was unaffected by the sugars tested. Human plasma and saliva were able to inhibit the co-aggregation in a dose-dependent reaction. Plasma exhibited the most potent inhibitory activity in these fluids. Fibrinogen was the most potent inhibitor of the plasma-derived proteins tested. These data suggest the possibility that the oral fluids may modulate the attachment of B. gingivalis to Gram-positive bacteria in periodontal pockets.

Specific Antibodies to Porphyromonas gingivalis Lys-Gingipain by DNA Vaccination Inhibit Bacterial Binding to Hemoglobin and Protect Mice from Infection

“…Bacterial cells were harvested, washed in prereduced sterile phosphate-buffered saline (PBS; 10 mM phosphate buffer containing 0.15 M sodium chloride [pH 7.4]), and resuspended in the same buffer. The number of bacteria in the suspension was estimated by measuring the optical density at 600 nm and extrapolated from a standard curve, as described previously (26). To prepare the bacterial extracts, washed cells were suspended in ice-cold PBS containing 3% (wt/vol) zwitterionic detergent 3-[(3-cholamidopropyl)-dimethylammonio]-1-propanesulfonate (CHAPS; Pierce, Rockford, Ill.) followed by stirring at 4°C for 40 min.…”

Glyceraldehyde-3-Phosphate Dehydrogenase of Streptococcus oralis Functions as a Coadhesin for Porphyromonas gingivalis Major Fimbriae

“…In addition, Yamaguchi et al (43) found that the glycoprotein of A. naeslundii (AnAF) mediates its coaggregation with P. gingivalis. However, little is known regarding the cell components of gram-positive bacteria or the mechanism involved in their coaggregation with P. gingivalis.In a series of studies, Nagata et al reported that P. gingivalis 381 coaggregates with S. oralis ATCC 9811 and that this activity was inhibited by human saliva and serum and especially human fibrinogen (29,30). The results also indicated that an arginine residue may be involved in the coaggregation (30) and that P. gingivalis 381 fimbriae mainly are responsible for the interaction with S. oralis ATCC 9811, with several domains in the carboxy terminus of fimbrillin being involved in the interaction (3).…”

“…In order to cause infection, it is necessary for P. gingivalis to attach to tooth surfaces, subgingival epithelium, or early colonizing gram-positive bacteria; this step constitutes the initial stage of colonization in periodontal pockets (38). In addition, the bacterium has been reported to interact with a variety of other oral gram-positive bacteria (19), including Actinomyces naeslundii (36,43), Actinomyces viscosus (9,12,26,27,36), Streptococcus gordonii (23), Streptococcus mutans (17), Streptococcus oralis (29), and Streptococcus sanguis (39); these interactions are considered to play a vital role in the colonization of P. gingivalis in the oral cavity.…”

Characterization of Binding of Streptococcus oralis Glyceraldehyde-3-Phosphate Dehydrogenase to Porphyromonas gingivalis Major Fimbriae

“…P. gingivalis interacts with a variety of other oral gram-positive bacteria, including Actinomyces naeslundii (16), Streptococcus gordonii (5), Streptococcus oralis (7), and Streptococcus sanguinis (14); these intergeneric coaggregations may lead to the initial colonization of P. gingivalis in the oral cavity.…”