Project description:Wild type Porphyromonas gingivalis strain ATCC33277 (V3176) and PG1626 - deficient mutant (V3177) were grown in iron replete conditions was used to compare to Porphyromonas gingivalis strains grown in iron chelated conditions.
Project description:This project investigated the phenotypic characteristics of Metronidazole-tolerant Porphyromonas gingivalis persisters, the relevant modulatory effects of hemin and their underlying survival mechanisms. Proteomic analysis was performed to delineate the protein expression profiles of Metronidazole-tolerant P. gingivalis persister fractions and the controls incubated with different levels of hemin supplementation.
Project description:HU protein regulates expression of genes involved in cell-division, iron acquisition, and transcriptional regulation in Porphyromonas gingivalis
Project description:RNA-Seq of wild-type Porphyromonas gingivalis compared to ΔPGN_1524 mutant Illumina based RNA-Seq was used to probe transcriptome differences between wild-type Porphyromonas gingivalis and ΔPGN_1524 mutant
Project description:Extracytoplasmic function (ECF) sigma factors are known to play an important role in the bacterial response to various environmental stresses. Porphyromonas gingivalis, a prominent etiological agent in human periodontitis, possesses six putative ECF sigma factors. So far, information is limited on an ECF sigma factor, PGN_0319. It has been recently reported that the expression of genes encoding some of the ECF sigma factors including PGN_0319 was affected by hemin availability. The aim of this study was to evaluate the role of PGN_0319 in hemin utilization by P. gingivalis. We evaluated the gene expression profile of the PGN_0319 mutant by DNA microarray, and then real-time reverse transcription PCR analysis was performed to assess genes with altered expression levels. The expressions level of hmuY and hmuR, which encode an outer-membrane protein involved in hemin utilization, and cdhR, a transcriptional regulator of hmuYR, were significantly decreased in the PGN_0319 mutant. The transcription of these genes was restored in the PGN_0319 complemented strain. We observed that the PGN_0319 mutant showed reduced growth in log phase compared with wild type under hemin-limiting condition. By electrophoretic mobility shift assay we demonstrated the recombinant PGN_0319 protein bound to the promoter region of hmuY and cdhR. In addition, we observed that PGN_0319 gene was upregulated in response to low cell density. These results demonstrate that PGN_0319 play an important role in the early growth of P. gingivalis, and directly regulates hmuYR and cdhR, thereby plays a role in the mechanisms involved in hemin utilization by P. gingivalis.
Project description:We report the study of the mechanism of action of Porphyromonas gingivalis on human oral epithelial cells based on high-throughput sequencing technology. By acting Porphyromonas gingivalis and its metabolites on human oral epithelial cells separately, the mechanism of Porphyromonas gingivalis evading immune surveillance and causing local and deep tissue diffusion to induce systemic diseases was studied. This study provides a framework for studying the pathogenic mechanism of Porphyromonas gingivalis.
Project description:Porphyromonas gingivalis (P. gingivalis) 381 and W83 growing in motility condition (i.e. stabbed in soft agar culture) and on surface of solid agar culture (Biofilm) were prepared. Applied medium was BAPHK supplemented with hemin and menadione . The cultures were then permitted to grow anaerobically at 37°C for 24 hours, which corresponds to initial stages of surface translocation by P. gingivalis. At this point, RNA extraction was performed using the cultures, and these samples were processed and submitted for RNA sequencing using an Illumina platform. Significant changes in gene expression were observed in cells growing in motility and biofilm modes , and the majority of changes were associated with cell surface proteins, membrane proteins, biosynthesis of folates and bioenergetic pathways.
Project description:Porphyromonas gingivalis is a major pathogen associated with the microbial biofilm-mediated disease chronic periodontitis. P. gingivalis has an obligate requirement for iron and protoporphyrin IX which it satisfies by transporting heme and iron liberated from the human host. The level of cellular iron in P. gingivalis affects the expression of a distinct iron-associated regulon of 64 genes and low iron invokes an iron sparing response. Iron homeostasis is usually mediated in Gram-negative bacteria at the transcriptional level by the Ferric Uptake Regulator (Fur). There is a single predicted P. gingivalis Fur superfamily orthologue named Har (heme associated regulator) that lacks the conserved metal binding residues found in other Fur orthologues. We show that Har binds both heme and ferrous iron resulting in a conformational change in the protein. Har was unable to complement the Escherichia coli H1780 fur mutant and there was no change in cellular metal content in a P. gingivalis Har mutant compared with the wild-type. The Har regulon of 44 genes is not predicted to play a role in iron homeostasis. Together these data indicated that Har does not regulate iron homeostasis in P. gingivalis. However, Har was required for heme-responsive biofilm development and its regulon overlapped P. gingivalis regulons previously identified after growth in heme limitation or as a homotypic biofilm. P. gingivalis is unique as an iron-dependent Gram-negative bacterium with a single heme-binding Fur superfamily orthologue, Har, that does not regulate iron homeostasis.