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:Background: Treponema denticola is strongly associated with the development of periodontal disease. Both synergistic and antagonistic effects are observed among bacterial species in the process of biofilm formation. Bacteriocin-related genes have not yet been fully characterized in periodontopathic bacteria. The aim of this study was to detect and characterize bacteriocin-associated proteins in T. denticola. Methods: The whole genome sequence of T. denticola ATCC 35405 was screened with a Streptococcus mutans bacteriocin immunity protein (ImmA/Bip) sequence. The prevalence of homologous genes in T. denticola strains was then investigated by Southern blotting. Expression of the genes was evaluated by qRT-PCR. Results: In the genome sequence of T. denticola, an amino acid sequence coded by open reading frame TDE_0719 showed 26% identity with the S. mutans ImmA. Furthermore, two protein sequences coded by TDE_0425 and TDE_2431 in T. denticola ATCC 35405 showed ~40% identity with that coded by TDE0719. Therefore, TDE_0425, TDE_0719, and TDE_2431 were designated as tepA1, A2, and A3, respectively. Open reading frames showing similarity to the HlyD family of secretion proteins were detected downstream of tepA1, A2, and A3. They were designated as tepB1, B2, and B3, respectively. A gene harboring a bacteriocin-like signal sequence was detected upstream of tepA1. The prevalence of tepA1 and A2 differed among Treponema species. Susceptibility to chloramphenicol and ofloxiacin was slightly decreased in a tepA2 mutant while that to kanamycin was increased. Expression of tepA3-B3 was increased in the tepA2 mutant. Conclusion: These results indicate that T. denticola ATCC 35405 has three potential bacteriocin export proteins and that the presence of these genes differs among the Treponema strains. These proteins may be involved in resistance to chloramphenicol.
Project description:The purpose of this study was to determine, at a global level, the transcriptomic responses of human gingival keratinocytes to T. denticola infection to better understand the disruption of normal barrier immunity that leads to the development of periodontal disease.
Project description:In the healthy subgingiva, oral treponemes account for a small percentage of the total bacteria. However, in diseased periodontal pockets, treponemes thrive and become a dominant component of the bacterial population. Oral treponemes are uniquely adept at capitalizing on the environmental conditions that develop with periodontal disease. The molecular basis of adaptive responses of oral treponemes is just beginning to be investigated and defined. The completion of several treponeme genome sequences and the characterization of global regulatory systems provide an important starting point in the analysis of signaling and adaptive responses. In this review, we discuss existing literature focused on the genetic regulatory mechanisms of Treponema denticola and present an overview of the possible roles of regulatory proteins identified through genome analyses. This information provides insight into the possible molecular mechanisms utilized by oral spirochetes to survive in the periodontal pocket and transition from a minor to a dominant organism.
Project description:Porphyromonas gingivalis and Treponema denticola are strongly associated with chronic periodontitis. These bacteria have been co-localized in subgingival plaque and demonstrated to exhibit symbiosis in growth in vitro and synergistic virulence upon co-infection in animal models of disease. Here we show that during continuous co-culture a P. gingivalis:T. denticola cell ratio of 6∶1 was maintained with a respective increase of 54% and 30% in cell numbers when compared with mono-culture. Co-culture caused significant changes in global gene expression in both species with altered expression of 184 T. denticola and 134 P. gingivalis genes. P. gingivalis genes encoding a predicted thiamine biosynthesis pathway were up-regulated whilst genes involved in fatty acid biosynthesis were down-regulated. T. denticola genes encoding virulence factors including dentilisin and glycine catabolic pathways were significantly up-regulated during co-culture. Metabolic labeling using 13C-glycine showed that T. denticola rapidly metabolized this amino acid resulting in the production of acetate and lactate. P. gingivalis may be an important source of free glycine for T. denticola as mono-cultures of P. gingivalis and T. denticola were found to produce and consume free glycine, respectively; free glycine production by P. gingivalis was stimulated by T. denticola conditioned medium and glycine supplementation of T. denticola medium increased final cell density 1.7-fold. Collectively these data show P. gingivalis and T. denticola respond metabolically to the presence of each other with T. denticola displaying responses that help explain enhanced virulence of co-infections.
Project description:While FbpA, a family of bacterial fibronectin (FN) binding proteins has been studied in several gram-positive bacteria, the gram-negative Treponema denticola, an anaerobic periodontal pathogen, also has an overlooked fbp gene (tde1579). In this research, we confirm that recombinant Fbp protein (rFbp) of T. denticola binds human FN with a Kdapp of 1.5 × 10(-7) M and blocks the binding of T. denticola to FN in a concentration-dependent manner to a level of 42%. The fbp gene was expressed in T. denticola. To reveal the roles of fbp in T. denticola pathogenesis, an fbp isogenic mutant was constructed. The fbp mutant had 51% reduced binding ability to human gingival fibroblasts (hGF). When hGF were challenged with T. denticola, the fbp mutant caused less cell morphology change, had 50% reduced cytotoxicity to hGF, and had less influence on the growth of hGF cells.