Expression patterns of <em>oxyR</em> induced by oxidative stress from <em>Porphyromonas gingivalis</em> in response to photo-activated disinfection

Abstract

IntroductionPorphyromonas gingivalis, an important endodontic pathogen, may be exposed to sublethal doses of photo-activated disinfection (sPAD) during root canal therapy. Such an exposure can affect bacterial survival and virulence features. In this study, we evaluated the effect of sPAD-related oxidative stresses on the expression of oxidative stress response gene (oxyR) in P. gingivalis clinical isolates surviving in vitro photodynamic treatment.Materials and methodsTo determine the sPAD, 16 clinical P. gingivalis isolates photosensitized with toluidine blue O (TBO), methylene blue (MB), and indocyanine green (ICG) were irradiated with specific wavelength and energy density of diode laser corresponding to the photosensitizers following bacterial viability measurements. The effects of sPAD on the expression ratio of oxyR of 16 clinical P. gingivalis isolates were then assessed using quantitative real-time PCR (qRT-PCR) assay.ResultsMaximum values of sPAD against P. gingivalis were 6.25, 15.6, and 25 μg/mL at fluencies of 171.87, 15.6, and 93.75 J/cm2, respectively, for TBO-, ICG-, and MB-sPAD (P>0.05). ICG-, MB-, and TBO-sPAD could increase the oxyR gene expression of the clinical P. gingivalis isolates 12.3-, 5.6-, and 8.5-fold, respectively. ICG-sPAD increased the expression of oxyR gene in clinical isolates of P. gingivalis ~1.5- and 2-fold higher than TBO- and MB-sPAD, respectively.ConclusionOur results showed that upregulation of oxyR during sPAD may lead to better survival and increased pathogenicity of P. gingivalis isolates. Therefore, selection of appropriate photo-activated disinfection dosage should be considered for the successful treatment of endodontic infection.

Validation of stable reference genes in Staphylococcus aureus to study gene expression under photodynamic treatment: a case study of SEB virulence factor analysis

“…One of the most frequently explored reference genes in bacterial gene expression studies is 16S rRNA . The 16S rRNA gene has been used in gene expression analysis of several aPDI-treated species in vitro, including P. gingivalis and S. aureus 22 , 31 ; ex vivo, including E. faecalis 32 ; and in biofilm cultures, including E. faecalis, P. aeruginosa and Streptococcus mutans 33 – 35 . Unfortunately, in the cited references, there are no data on the stability of the selected genes under the studied conditions.…”

Antibacterial properties of an acrylic resin containing curcumin nanoparticles: An in vitro study

“…Moreover, curcumin has the potential to attenuate pathogenic traits of S. mutans biofilms. 22 , 26 , 27 …”

“…Finally, the plates were incubated at 37°C for 24 hours under optimal conditions for each microorganism. The number of colonies was then counted using the “Miles et al method.” 22 The antimicrobial activity was assessed by the eluted component test at 3 and 7 days using the same method.…”

DNA-aptamer-nanographene oxide as a targeted bio-theragnostic system in antimicrobial photodynamic therapy against Porphyromonas gingivalis

“…The extracted RNAs were first treated with RNase-free DNase I treatment (Thermo Scientific GmbH, Germany) to eliminate the genomic DNAs, and cDNAs were then synthesized using random hexamer primed reactions using a Revert Aid First Strand cDNA Synthesis Kit (Thermo Fisher Scientific, US), according to the manufacturer’s protocol. The gene-specific primers were designed according to our previous studies 43 – 45 and listed in Table 1 .…”