Project description:Porphyromonas gingivalis and Treponema denticola are periodontalpathogens that are associated with the severity and progression of periodontal diseases. This study investigates the gene expression of Porphyromonas gingivalis during co-culture with Treponema denticola
Project description:Porphyromonas gingivalis and Treponema denticola are periodontalpathogens that are associated with the severity and progression of periodontal diseases. this study investigates the gene expression of Treponema denticola during co-culture with Porphyromonas gingivalis.
Project description:Treponema denticola is a major pathogen in periodontal disease, frequently isolated from lesions of chronic periodontitis. The ability to adopt its environment is believed to be important for T. denticola in colonizing and proliferating in the gingival crevice. T. denticola use serum as a major nutrient source in the gingival crevices, suggesting that this microorganism utilize serum components to proliferate in gingival crevice. The purpose of this study was to identify T. denticola serum utilization genes. Precultured T. denticola were suspended in tryptone-yeast extract-gelatin-volatile fatty acids medium containing 0, 1 and 10% serum, and incubated anaerobically for 17 h. Total RNA was isolated and T. denticola gene expression was compared by microarray and reverse transcription-polymerase chain reaction. In serum-depleted conditions, the expression of a potential hydroxylamine reductase, several ABC transporters, and phosphoenolpyruvate synthase were increased, while methyl-accepting chemotaxis proteins and a transcriptional regulator were decreased. The results suggest that T. denticola may uptake serum components via ABC transporters. Decreased dmcA expression with decreased serum concentration suggests its involvement in chemotaxis toward serum-rich environments.
Project description:There is growing evidence that a number of oral Treponema species, in particular Treponema denticola, are associated with the progression of human periodontal disease. The major sheath (or surface) protein (Msp) of T. denticola is implicated in adhesion of bacteria to host cells and tissue proteins and is likely to be an important virulence factor. However, the binding regions of the Msp are not known. We have purified from Escherichia coli recombinant Msp (rMsp) polypeptides corresponding to the following: full-length Msp (rMsp) minus 13 N-terminal amino acid (aa) residues, an amino-terminal fragment (rN-Msp, 189 aa residues), a 57-aa residue segment from the central region (rV-Msp), and a C-terminal fragment (rC-Msp, 272 aa residues). rMsp (530 aa residues) bound to immobilized fibronectin, keratin, laminin, collagen type I, fibrinogen, hyaluronic acid, and heparin. The N- and V-region polypeptides, but not rC-Msp, also bound to these substrates. Binding of rMsp to fibronectin was targeted to the N-terminal heparin I/fibrin I domain. Antibodies to the N-region or V-region polypeptides, but not antibodies to the rC-Msp fragment, blocked adhesion of T. denticola ATCC 35405 cells to a range of host protein molecules. These results suggest that the N-terminal half of Msp carries epitopes that are surface exposed and that are involved in mediating adhesion. Binding of rMsp onto the cell surface of low-level fibronectin-binding Treponema isolates conferred a 10-fold increase in fibronectin binding. This confirms that Msp functions autonomously as an adhesin and raises the possibility that phenotypic complementation of virulence functions might occur within mixed populations of Treponema species.
