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:The role of ECF sigma factors PG0162, PG01660 were involved in virulence regulationin Porphyromonas gingivalis was published Yuetan Dou, Devon Osbourne, Rachelle McKenzie, Hansel M Fletcher. (2010) Involvement of extracytoplasmic function sigma factors in virulence regulation in Porphyromonas gingivalis W83. FEMS Microbiology Letter, 312(1):24-32.
Project description:To study the expression profile of ECF sigma factor PG1660 mutant under anaerobic conditions and hydrogen peroxide stress conditions compared to the wild-type W83 by using DNA-microarray. The role of ECF sigma factor PG1660 involved in oxidative stress was published Yuetan Dou, Devon Osbourne, Rachelle McKenzie, Hansel M Fletcher. (2010) Involvement of extracytoplasmic function sigma factors in virulence regulation in Porphyromonas gingivalis W83. FEMS Microbiology Letter, 312(1):24-32.
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: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.
