Growth Of Porphyromonas Gingivalis Research Articles

Antibacterial activity of erythritol on periodontal pathogen

To explore the effect of erythritol on the growth of Porphyromonas gingivalis (Pg), Aggregatibacter actinomycetemcomitans(Aa), Actinomices viscosus (Av), and to explore how Porphyromonas gingivalis affected by erythritol influence mRNA expression level of inflammatory in periodontal cells. Pg, Aa, Av were anaerobically cultured (80%N2, 10%CO2, 10%H2) at 37℃ in 2, 4, 8, 16, 32, 64, 128 g/L erythritol- BHI mixture groups (experimental groups) and BHI groups (control group). The lowest erythritol concentration without turbidity or precipitation was the minimum inhibitory concentration. Pg was cultured in MIC, 1/2, 1/4, 1/8 MIC erythritol- BHI mixture groups (experimental groups) and BHI groups (control group). Each kind of bacteria in each concentration group was centrifugalled and cleaned before added into DMEM. The mixed suspension was co-cultured with the periodontal ligament cells in four generations for 24 hours, the supernatan was removed , then the total RNA in cracking cells was extracted and reversing transcription. At last, the relative expression of IL-1, IL-6, TNF-a was detected real-time fluorescent quantitative PCR. The data were analyzed with SPSS19.0 software package. The minimum inhibitory by concentrations of erythritol on three bacteria were as followed: Pg: 64 g/L，Aa: 128 g/L，Av: 128 g/L. The ability of stimulating periodontal ligament cells to produce IL-1β, IL-6 and TNF-α was different when Pg was cultured under different concentrations of erythritol. There was no significant difference between 0 g/L of control group and 8 g/L of experimental group. As the concentration reached 16 g/L, the relative expression of IL-1β, IL-6, TNF-α was reduced, and the higher concentration was, the less inflammatory factors was. However, the inflammatory factors in all the experimental groups were always significantly higher than that in the blank control group (P<0.05). Erythritol has an inhibitory effect on the growth of Pg, Aa and Av. In a certain range, higher concentration of erythritol delivers better inhibition effect. Erythritol can also reduce the periodontal pathogenicity of pathogenic bacteria in a way inhibiting the virulence of these bacteria, reducing the production of IL-1β, IL-6, and TNF-a in periodontal cells.

INHIBITORY TEST OF FLAVONOID PROPOLIS KELULUT EXTRACTS (G. thorasica) ON Porphyromonas gingivalis AS AN ETIOLOGIC FACTOR OF CHRONIC PERIODONTITIS

Background : Natural ingredients have been used recently for its ability in curing various diseases and reducing the risk of antibiotic resistance . One of these natural ingredients is propolis. Bee propolis Geniotrigona thorasica from South Kalimantan has a strong antibacterial activity with active compounds such as flavonoids. Flavonoids can damage cell membranes and can fight the expansion of β-lactamase enzyme produced by gram-negative bacteria. Porphyromonas gingivalis is a gram-negative bacterium that causes chronic periodontitis with a prevalence of 80%. Objective : This study was to find out the inhibitory test of flavonoid propolis kelulut extract at the concentration of 0.1%; 0.3% and 0.5% on Porphyromonas gingivalis bacteria. Method : This type of research used a pure experimental method with post-test only and control group design. One-way ANOVA statistical test was performed with follow-up test of Post Hoc Dunnet’s T3 . Treatment was given to 4 groups with 5 repetitions. Observations were carried out using digital calipers in all groups after incubation for 24 hours with a temperature of 37℃. Results : One Way Anova and Post Hoc Dunnet's T3 showed significant differences in the diameter flavonoid propolis extract inhibitory zone against Porphyromonas gingivalis . The average value of Flavonoid extract inhibitory zone after 24 hours observation with a concentration of 0.5%; 0.3%; 0.1% and sterile distilled water were 25.24 mm; 18.04 mm; 13.58 mm and there was no inhibitory zone observed in sterile distilled water group . Conclusion : Extract of flavonoid propolis kelulut at the concentration of 0.1%; 0.3% and 0.5% can inhibit the growth of Porphyromonas gingivalis as an etiologic factor of chronic periodontitis.

Inhibition of namnam (Cynometra cauliflora L.) leaves extract on the growth of Porphyromonas gingivalis

Introduction: Porphyromonas gingivalis growth should be prevented to minimise inflammation in periodontal tissues. Antibacterial herbs need to be considered because there are side effects caused by synthetic antibacterial drugs. Namnam (Cynometra cauliflora L.) leaves are known for having antibacterial effects. The purpose of this research was analysing the inhibition potential, and the highest inhibition concentration of namnam leaves extract on the growth of Porphyromonas gingivalis. Methods: 24 samples were divided into 6 groups. The positive control group was given 0.2% chlorhexidine, and the treatment group was given various concentrations (100%, 80%, 60%, 40%, and 20%) of namnam leaves extract. The disc which spilled by various concentrations of namnam leaves extracts and 0.2% chlorhexidine was placed on a medium which has been inoculated by P. gingivalis, then incubated at 37ºC for 48 hours. The inhibition zone was measured using a vernier calliper. Results: The concentration of 100% had the highest average inhibition zone value, which was 11.43 mm. The content in namnam leaves extracts which serve as antibacterial were tannins, flavonoids, triterpenoids, saponins and quinones. Conclusion: Namnam leaves extract can inhibit the growth of P. gingivalis. 100% of namnam leaves extract has the highest antibacterial inhibition zone.Keywords: Antibacterial, Namnam leaves extract, periodontal disease, Porphyromonas gingivalis

Activation of local innate immune signal induces periodontitis in microbiota-dependent manner.

Periodontitis is a chronic inflammatory disease. Both inflammation and dysbiosis have been implicated in periodontitis development. However, the relationship between local inflammation and dysbiosis, and the precise roles of local inflammation in periodontitis are not well-elucidated. In present study, we explored the role of local inflammation in periodontitis. We established a periodontitis model by administration of Pam3CSK4 to local oral area and compared the difference of outcome between local and systemic administration. We monitored the pro-inflammatory cytokine expression, local inflammation and alveolar bone loss. We also evaluated the dysbiosis, NF-κB activation. Local but not systemic administration of Pam3CSK4-induced pro-inflammatory cytokines productions and finally resulted in periodontitis. Pam3CSK4 caused dysbiosis and promoted Porphyromonas gingivalis growth. The bacterial growth and NF-κB activation were required for Pam3CSK4-induced periodontitis. We evaluated the effect of local inflammation by inducing TLR2 activation on dysbiosis and periodontitis. Activation of local innate immune signal induces periodontitis in microbiota-dependent manner.

Hainosan (painongsan) suppresses the biofilm formation of Porphyromonas gingivalis and Prevotella intermedia in vitro

ABSTRACTAim Porphyromonas gingivalis and Prevotella intermedia are pathogenic bacteria that cause several periodontal diseases such as periodontitis. They frequently form biofilm to protect from threats such as antimicrobial agents. Hainosan (painongsan in Chinese) is a Japanese traditional kampo and traditional Chinese medicine formula used to treat acute and chronic purulent disease. The aim of the present study was to elucidate the mechanism of antibacterial effects such as anti‐biofilm activity, of hainosan extract (HNS) against Porphyromonas gingivalis and Prevotella intermedia.MethodsThe antibacterial and anti‐biofilm activity of HNS was examined on bacterial turbidity and colony‐forming unit analysis, transmission electron microscopy, microplate analysis, and hydrophobicity and auto‐aggregation analysis.ResultsHNS significantly suppressed the growth of Porphyromonas gingivalis and Prevotella intermedia. It also significantly inhibited the formation of biofilm from Porphyromonas gingivalis and Prevotella intermedia. The size and shape of HNS‐treated Porphyromonas gingivalis and Prevotella intermedia were significantly smaller and irregular. Furthermore, HNS reduced the bacterial auto aggregation and hydrophobicity of the bacterial cell surface. These antibacterial effects of HNS were greater than those of hangeshashinto, another Japanese traditional kampo medicine formula for oral cavity inflammation.ConclusionHNS may be useful for the treatment of Porphyromonas gingivalis and Prevotella intermedia‐induced periodontitis because of the inhibition of bacterial biofilm formation.

Berberine promotes osteogenic differentiation of mesenchymal stem cells with therapeutic potential in periodontal regeneration

Periodontal disease is a bacterial infection-associated disease of the periodontal tissues characterized by the destruction of tooth-supporting structures, including alveolar bone. The ideal goal of periodontal therapy is the complete regeneration of alveolar bone in a healthy microenvironment free of infection. In this study, we found that berberine, a benzylisoquinoline plant alkaloid from Coptidis Rhizoma, strongly inhibited the growth of Porphyromonas gingivalis. Gingipain is the most important virulence factor of Porphyromonas gingivalis in the process of periodontal tissue destruction. Berberine also had an inhibitory effect on gingipain activity in a concentration dependent manner. Remarkably, berberine restored the downregulation of osteogenesis-related genes expression in bone mesenchymal stem cells (BMSCs) induced by Porphyromonas gingivalis infection, and significantly increased the expression of osteogenesis-related genes such as OSX, COLI, ALP, OCN and OPN compared to the control group. This results suggested that berberine may directly promote osteogenesis. Further in-vitro studies demonstrated that berberine statistically significantly promoted the osteogenic differentiation of BMSCs at concentrations of 1–10 μM. In the research on the mechanisms, we found that both total β-catenin and nuclear β-catenin accumulation were statistically significantly increased by berberine. And the transcriptional activity of β-catenin/TCF was about 2 folds higher than the control group. Furthermore, Wnt signalling specific inhibitor DKK-1 blocked the above effects of berberine. These demonstrated that Wnt/β-catenin signalling pathway was involved in the osteogenic differentiation induced by berberine. The antibacterial actions in combination with the promotion role in osteogenic differentiation position berberine as a prospective drug for periodontal tissue regeneration.

Effects of Lactobacillus salivarius WB21 combined with green tea catechins on dental caries, periodontitis, and oral malodor

ObjectiveTo evaluate the combined use of Lactobacillus salivarius WB21 and (–)-epigallocatechin gallate (EGCg) for oral health maintenance. DesignThe effects of L. salivarius WB21 on growth of Streptococcus mutans, the insoluble glucan produced by S. mutans, and on growth of Porphyromonas gingivalis were evaluated in vitro. In addition, the susceptibility of five oral pathogenic bacteria and L. salivarius WB21 to EGCg, the inhibiting effect of EGCg on methyl mercaptan, and the effects of L. salivarius WB21 and EGCg in combination on growth of P. gingivalis were examined. ResultsLactobacillus salivarius WB21 showed concentration-dependent inhibition of the growth of S. mutans. Addition of L. salivarius WB21 inhibited production of the insoluble glucan by S. mutans (p < 0.001). A filtrate of L. salivarius WB21 culture solution inhibited growth of P. gingivalis (p < 0.001 vs. control), and this effect was enhanced when it was used in combination with EGCg (p < 0.001 vs. the addition of L. salivarius WB21). In addition, EGCg directly inhibited methyl mercaptan in a concentration-dependent manner (p < 0.001). Concerning bacterial susceptibility to EGCg, growth of P. gingivalis, Prevotella intermedia, and Fusobacterium nucleatum was inhibited at 2.5 mg/mL of EGCg, while that of L. salivarius WB21 was inhibited at 25 mg/mL EGCg. ConclusionsOur results imply that L. salivarius WB21 may be useful for controlling dental caries, periodontitis, and oral malodor. In addition, the effects of L. salivarius WB21 on periodontitis and oral malodor may be synergistically enhanced by use in combination with EGCg.

DAYA HAMBAT GEL PROPOLIS DARI SULAWESI SELATAN TERHADAP PERTUMBUHAN BAKTERI PORPHYROMONAS GINGIVALIS

Background : Periodontal disease is caused by various factors.Bacterial deposit plays an important role against the occurrence of periodontal disease. One of the bacterias that contribute to the occurrence of periodontal disease is Porphyromonas gingivalis. Propolis is a natural substance contains antibacterial properties which are different depends on the type of propolis. Propolis has been used for the treatment of apthous ulcer, candidiasis, gingivitis, periodontitis, and pulpitis. Purpose : The purpose of the study is determine propolis gel Trigona sp inhibitionfrom South Sulawesi on the growth of Porphyromonas gingivalis. Methods : This research is an experimental laboratories. Inhibition test performed a diffusion method using propolis and metronidazole gel.Inhibition zone of propolis and metronidazole gel against Porphyromonas gingivalis were measured using calipers after incubation 1x24 hours, 2x24 hours, and 3x24 hours. Result :The zone of propolis gel and metronidazole gel inhibition against Porphyromonas gingivalis observed in1x24 hours, 2x24 hours, 3x24 hours.Propolis gel consecutive are6.17±0.48 mm, 5.76±0.55 mm, 5.23±0.32 mm, whereas metronidazole gelconsecutive are 13.68 ± 1.66, 13.94 ± 2:03, 12.90 ± 1.96 mm, and the difference of both inhibition zone based on time 1x24 hours, 2x24 hours, 3x24 hours are7.51, 8.18, 7.66 mm. Conclusion: South Sulawesi propolis gel have inhibitory effect on the growth of P. gingivalis bacteria. While the inhibition zone of South Sulawesi propolis gel is smaller than Metronidazole gel.

New Application of Psoralen and Angelicin on Periodontitis With Anti-bacterial, Anti-inflammatory, and Osteogenesis Effects

Psoralen and angelicin are two effective compounds isolated from psoraleae, a traditional Chinese medicine. They have a wide range of applications for bone disease treatment and immune modulation. In this study, we explored their new applications for the treatment of periodontal diseases. This study aimed to investigate the effects of psoralen and angelicin on Porphyromonas gingivalis growth and P. gingivalis-derived lipopolysaccharide (Pg-LPS)-induced inflammation, and further to evaluate their effects on osteogenesis. Finally, the effects of angelicin on a mouse model of periodontitis were also investigated. The results showed that psoralen and angelicin had beneficial dose-dependent effects regarding the inhibition of planktonic P. gingivalis and biofilms of P. gingivalis. There were no significant differences in the viability of monocyte-like THP-1 cells and human periodontal ligament cells (hPDLCs) treated with either psoralen or angelicin compared to the untreated control cells. Psoralen and angelicin also markedly decreased the mRNA expression and release of inflammatory cytokines (interleukin [IL]-1β and IL-8) by THP-1 cells in a dose-dependent manner. They significantly enhanced the alkaline phosphatase (ALP) activity of hPDLCs and up-regulated the expression of osteogenic proteins (runt-related transcription factor 2 [RUNX2], distal-less homeobox 5 [DLX5], and osteopontin [OPN]). Angelicin significantly attenuated alveolar bone loss and inflammation response in the mice with periodontitis. In conclusion, our data demonstrated that psoralen and angelicin could inhibit the growth of planktonic P. gingivalis and P. gingivalis biofilm. It is also the first report on the anti-inflammatory effect of psoralen and angelicin against Pg-LPS. They also had an osteogenesis-potentiating effect on hPDLCs. The in vivo study also indicated the effect of angelicin regarding protection against periodontitis. Our study highlighted the potential ability of psoralen and angelicin to act as novel natural agents to prevent and treat periodontitis.

Effect of Manuka Honey and Licorice Root Extract on the Growth of Porphyromonas gingivalis: An In Vitro Study

Chronic bad breath (also known as “halitosis”) is very common in general population and nearly 50% of the general population have halitosis. Liquid mouthwashes such as Listerine®, and ACT®, mouth fresheners, and sugar-free gum are commonly used to alleviate bad breath, but these products are not portable, have many side effects, or only temporarily mask the problem. Hence, a lozenge made from natural ingredients would be an excellent alternative to reduce bad breath. We evaluated the effectiveness of natural ingredients such as Manuka Honey and Licorice root extract in reducing growth of Porphyromonas gingivalis, one of the main bacteria that cause bad breath. Solutions containing Manuka honey and/or licorice root extract, Listerine®, or ACT® were added to P. gingivalis cultures to assess their effect on bacterial growth. After 18 hours, the absorbance at 680nm of each solution was measured as an indicator of growth. We found that Manuka honey is almost as effective as Listerine® and ACT® in reducing P. gingivalis growth, while licorice root extract, had a very minor effect. Aliquots from the cultures that were inoculated on to brain heart infusion (BHI) plates showed similar trends on growth inhibition. These data suggest that a natural lozenge made from Manuka honey may be effective in reducing bad breath.

Preventive effects of the novel antimicrobial peptide Nal-P-113 in a rat Periodontitis model by limiting the growth of Porphyromonas gingivalis and modulating IL-1\u03b2 and TNF-\u03b1 production

BackgroundP-113 (AKRHHGYKRKFH-NH2) is a 12-amino-acid histidine-rich peptide derived from histatin 5 that is highly degradable in high salt concentrations and biological fluids such as serum, plasma and saliva. Nal-P-113, a novel antimicrobial peptide whose histidine residues are replaced by the bulky amino acids β-naphthylalanine, causes the antimicrobial peptide to retain its bactericidal activity even in physiological environments. This study evaluated the effect of the novel antimicrobial peptide Nal-P-113 in a rat periodontitis model and the mechanisms of action of Nal-P-113 for suppressing periodontitis.MethodsPeriodontitis was induced in mandibular first molars in rats receiving a ligature and infected with Porphyromonas gingivalis. Animals were randomly divided into six groups: a, P. gingivalis W83 alone; b, P. gingivalis W83 with 6.25 μg/mL of Nal-P-113; c, P. gingivalis W83 with 25 μg/mL of Nal-P-113; d, P. gingivalis W83 with 100 μg/mL of Nal-P-113; e, P. gingivalis W83 with 400 μg/mL of Nal-P-113; and f, control without P. gingivalis W83 or Nal-P-113. Morphometric analysis was used to evaluate alveolar bone loss. Microbiological assessment of the presence of Porphyromonas gingivalis and total bacteria was performed using absolute quantitative real-time PCR and scanning electron microscopy. Gingival tissue was collected for western blot and immunohistochemical assays of IL-1β and TNF-α levels.ResultsAlveolar bone loss was inhibited by 100 μg/mL or 400 μg/mL of Nal-P-113 compared to the control group (P < 0.05). Lower amounts of P. gingivalis and total bacteria were found in groups d and e compared with group a (P < 0.05). A decrease in the levels of IL-1β and TNF-α was detected in group d and group e compared to the control group (P < 0.05). The amount of P. gingivalis was positively correlated with IL-1β and TNF-α expression in periodontal tissue (P < 0.05).ConclusionsNal-P-113 exhibited protective effects on Porphyromonas gingivalis-induced periodontitis in rats by limiting the amount of bacteria and modulating IL-1β and TNF-α production. The use of Nal-P-113 in vivo might serve as a beneficial preventive or therapeutic approach for periodontitis.

Melatonin Receptor Agonists as the "Perioceutics" Agents for Periodontal Disease through Modulation of Porphyromonas gingivalis Virulence and Inflammatory Response.

Aim“Perioceutics” including antimicrobial therapy and host modulatory therapy has emerged as a vital adjunctive treatment of periodontal disease. Melatonin level was significantly reduced in patients with periodontal diseases suggesting melatonin could be applied as a potential “perioceutics” treatment of periodontal diseases. This study aims to investigate the effects of melatonin receptor agonists (melatonin and ramelteon) on Porphyromonas gingivalis virulence and Porphyromonas gingivalis-derived lipopolysaccharide (Pg-LPS)-induced inflammation.MethodsEffects of melatonin receptor agonists on Porphyromonas gingivalis planktonic cultures were determined by microplate dilution assays. Formation, reduction, and viability of Porphyromonas gingivalis biofilms were detected by crystal violet staining and MTT assays, respectively. Meanwhile, biofilms formation was also observed by confocal laser scanning microscopy (CLSM). The effects on gingipains and hemolytic activities of Porphyromonas gingivalis were evaluated using chromogenic peptides and sheep erythrocytes. The mRNA expression of virulence and iron/heme utilization was assessed using RT-PCR. In addition, cell viability of melatonin receptor agonists on human gingival fibroblasts (HGFs) was evaluated by MTT assays. After pretreatment of melatonin receptor agonists, HGFs were stimulated with Pg-LPS and then release of cytokines (IL-6 and lL-8) was measured by enzyme-linked immunosorbent assay (ELISA).ResultsMelatonin and ramelteon did exhibit antimicrobial effects against planktonic culture. Importantly, they inhibited biofilm formation, reduced the established biofilms, and decreased biofilm viability of Porphyromonas gingivalis. Furthermore, they at sub-minimum inhibitory concentration (sub-MIC) concentrations markedly inhibited the proteinase activities of gingipains and hemolysis in a dose-dependent manner. They at sub-MIC concentrations significantly inhibited the mRNA expression of virulence factors (kgp, rgpA, rgpB, hagA, and ragA), while increasing the mRNA expression of ferritin (ftn) or hemolysin (hem). They did not show obvious cytotoxicity toward HGFs. They inhibited Pg-LPS-induced IL-6 and IL-8 secretion, which was reversed by luzindole, the melatonin receptor antagonist.ConclusionMelatonin receptor agonists can inhibit planktonic and biofilm growth of Porphyromonas gingivalis by affecting the virulent properties, as well as Pg-LPS-induced inflammatory response. Our study provides new evidence that melatonin receptor agonists might be useful as novel “perioceutics” agents to prevent and treat Porphyromonas gingivalis-associated periodontal diseases.

Antibacterial activity of extract of cashew (Anacardium occidentale) on the growth of Porphyromonas gingivalis

Antibacterial activity of extract of cashew (Anacardium occidentale) on the growth of Porphyromonas gingivalis

A Modified Glycosaminoglycan, GM-0111, Inhibits Molecular Signaling Involved in Periodontitis.

BackgroundPeriodontitis is characterized by microbial infection, inflammation, tissue breakdown, and accelerated loss of alveolar bone matrix. Treatment targeting these multiple stages of the disease provides ways to treat or prevent periodontitis. Certain glycosaminoglycans (GAGs) block multiple inflammatory mediators as well as suppress bacterial growth, suggesting that these GAGs may be exploited as a therapeutic for periodontitis.MethodsWe investigated the effects of a synthetic GAG, GM-0111, on various molecular events associated with periodontitis: growth of Porphyromonas gingivalis (P. gingivalis) and Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) pathogenic bacteria associated with periodontitis; activation of pro-inflammatory signaling through TLR2 and TLR4 in mouse macrophage RAW 264.7 cells and heterologously expressed HEK 293 cells; osteoclast formation and bone matrix resorption in cultured mouse pre-osteoclasts.Results(1) GM-0111 suppressed the growth of P. gingivalis and A. actinomycetemcomitans even at 1% (w/v) solution. The antibacterial effects of GM-0111 were stronger than hyaluronic acid (HA) or xylitol in P. gingivalis at all concentrations and comparable to xylitol in A. actinomycetemcomitans at ≥2% (w/v) solution. We also observed that GM-0111 suppressed biofilm formation of P. gingivalis and these effects were much stronger than HA. (2) GM-0111 inhibited TLR-mediated pro-inflammatory cellular signaling both in macrophage and HEK 293 cells with higher selectivity for TLR2 than TLR4 (IC50 of 1–10 ng/mL vs. > 100 μg/mL, respectively). (3) GM-0111 blocked RANKL-induced osteoclast formation (as low as 300 ng/mL) and bone matrix resorption. While GM-0111 showed high affinity binding to RANKL, it did not interfere with RANKL/RANK/NF-κB signaling, suggesting that GM-0111 inhibits osteoclast formation by a RANKL-RANK-independent mechanism.ConclusionsWe report that GM-0111 inhibits multiple molecular events involved in periodontitis, spanning from the early pro-inflammatory TLR signaling, to pathways activated at the later stage component of bone loss.

Bifidobacteria inhibit the growth of Porphyromonas gingivalis but not of Streptococcus mutans in an in vitro biofilm model.

There is growing interest in the use of probiotic bifidobacteria for enhancement of the therapy, and in the prevention, of oral microbial diseases. However, the results of clinical studies assessing the effects of bifidobacteria on the oral microbiota are controversial, and the mechanisms of actions of probiotics in the oral cavity remain largely unknown. In addition, very little is known about the role of commensal bifidobacteria in oral health. Our aim was to study the integration of the probiotic Bifidobacterium animalis subsp. lactis Bb12 and of oral Bifidobacterium dentium and Bifidobacterium longum isolates in supragingival and subgingival biofilm models and their effects on other bacteria in biofilms in vitro using two different in vitro biofilms and agar-overlay assays. All bifidobacteria integrated well into the subgingival biofilms composed of Porphyromonas gingivalis, Actinomyces naeslundii, and Fusobacterium nucleatum and decreased significantly only the number of P. gingivalis in the biofilms. The integration of bifidobacteria into the supragingival biofilms containing Streptococcus mutans and A. naeslundii was less efficient, and bifidobacteria did not affect the number of S. mutans in biofilms. Therefore, our results suggest that bifidobacteria may have a positive effect on subgingival biofilm and thereby potential in enhancing gingival health; however, their effect on supragingival biofilm may be limited.

A Porphyromonas gingivalis Periplasmic Novel Exopeptidase, Acylpeptidyl Oligopeptidase, Releases N-Acylated Di- and Tripeptides from Oligopeptides

Exopeptidases, including dipeptidyl- and tripeptidylpeptidase, are crucial for the growth of Porphyromonas gingivalis, a periodontopathic asaccharolytic bacterium that incorporates amino acids mainly as di- and tripeptides. In this study, we identified a novel exopeptidase, designated acylpeptidyl oligopeptidase (AOP), composed of 759 amino acid residues with active Ser(615) and encoded by PGN_1349 in P. gingivalis ATCC 33277. AOP is currently listed as an unassigned S9 family peptidase or prolyl oligopeptidase. Recombinant AOP did not hydrolyze a Pro-Xaa bond. In addition, although sequence similarities to human and archaea-type acylaminoacyl peptidase sequences were observed, its enzymatic properties were apparently distinct from those, because AOP scarcely released an N-acyl-amino acid as compared with di- and tripeptides, especially with N-terminal modification. The kcat/Km value against benzyloxycarbonyl-Val-Lys-Met-4-methycoumaryl-7-amide, the most potent substrate, was 123.3 ± 17.3 μm(-1) s(-1), optimal pH was 7-8.5, and the activity was decreased with increased NaCl concentrations. AOP existed predominantly in the periplasmic fraction as a monomer, whereas equilibrium between monomers and oligomers was observed with a recombinant molecule, suggesting a tendency of oligomerization mediated by the N-terminal region (Met(16)-Glu(101)). Three-dimensional modeling revealed the three domain structures (residues Met(16)-Ala(126), which has no similar homologue with known structure; residues Leu(127)-Met(495) (β-propeller domain); and residues Ala(496)-Phe(736) (α/β-hydrolase domain)) and further indicated the hydrophobic S1 site of AOP in accord with its hydrophobic P1 preference. AOP orthologues are widely distributed in bacteria, archaea, and eukaryotes, suggesting its importance for processing of nutritional and/or bioactive oligopeptides.

HmuY is an important virulence factor for Porphyromonas gingivalis growth in the heme-limited host environment and infection of macrophages

Porphyromonas gingivalis, the main etiologic agent and key pathogen responsible for initiation and progression of chronic periodontitis, is a haem auxotroph, and the uptake of this compound is essential for its survival and the ability to establish an infection. The aim of this study was to examine the role of a hemophore-like HmuY protein in P. gingivalis growth and infection of macrophages. Inactivation of the hmuY gene caused reduced P. gingivalis growth in vitro in the presence of serum as a heme sole source, as well as in vivo co-cultures with THP-1-derived macrophages. This resulted in diminished invasion efficiency of macrophages by live bacteria lacking functional hmuY gene. Both features were partially restored after addition of the purified HmuY protein, which was internalized when added either together with the hmuY mutant strain or alone to macrophage cultures. We conclude that HmuY is an important virulence factor of P. gingivalis for infection of macrophages in a heme-limited host environment.

Antibacterial and Antifungal Effect of 405 nm Monochromatic Laser on Endodontopathogenic Microorganisms

The purpose of this study is to evaluate the usefulness of 405 nm monochromatic laser irradiation as an alternative management for prevention and/or treatment of endodontic infections. A monochromatic laser-emitting device equipped with a 405-nm laser diode was developed. Using this device, the effect of 405 nm laser irradiation on the growth ofPorphyromonas gingivalis, Prevotella intermedia, Enterococcus faecalis, andCandida albicans, which are microorganisms associated with persistent endodontic infections, was evaluated by viable colony counting. As a result, the irradiation with a 405 nm laser had a significant bactericidal/fungicidal effect onP. gingivalis, P. intermedia, andC. albicans, whereas the growth ofE. faecaliswas not affected by the irradiation. The inhibition rate inP. gingivalisandP. intermediawas ~60% and ~80%, respectively, following irradiation at 0.2 W for 300 sec. The inhibition rate inC. albicanswas ~90% following irradiation at 0.2 W for 1200 sec. These results indicate that 405 nm monochromatic laser irradiation exerts a bactericidal/fungicidal effect on these microorganisms. The present study clearly demonstrates that 405 nm laser irradiation is a promising alternative management strategy for prevention and/or treatment of endodontic infections.

Synthesis of TiO2 nanotubes with ZnO nanoparticles to achieve antibacterial properties and stem cell compatibility.

To endow titanium (Ti) with antibacterial properties, different concentrations of zinc oxide (ZnO) nanoparticles were decorated on anodized titanium dioxide (TiO2) nanotubes by a simple hydrothermal treatment method. The particle sizes of ZnO, which were evenly distributed and tightly adherent to the walls of the Ti nanotubes, ranged from 20-50 nm. Results from this study showed that Zn was released from the TiO2 nanotubes in a constant, slow, and biologically inspired manner. Importantly, the results showed that the ZnO decorated TiO2 nanotubular samples inhibited Streptococcus mutants and Porphyromonas gingivalis growth compared to control unmodified Ti samples. Specifically, S. mutants and P. gingivalis growth were both reduced 45-85% on the ZnO decorated Ti samples compared to Ti controls after 7 days of culture. When examining the mechanism of action, it has been further found for the first time that the ZnO decorated Ti samples inhibited the expression of Streptococcus mutans bacterial adhesion genes. Lastly, the results showed that the same samples which decreased bacterial growth the most (0.015 M precursor Zn(NO3)2 samples) did not inhibit mesenchymal stem cell growth compared to Ti controls for up to 7 days. In summary, results from this study showed that compared to plain TiO2 nanotubes, TiO2 decorated with 0.015 M ZnO provided unprecedented antibacterial properties while maintaining the stem cell proliferation capacity necessary for enhancing the use of Ti in numerous medical applications, particularly in dentistry.

EFFECTIVENESS OF 5% GUAVA LEAF (Psidium guajava Linn) EXTRACT OF WHITE FRUIT VARIANT TO DECREASE LEVELS OF Volatile Sulfur Compounds (VSCs) IN HALITOSIS SUFFERERS

Halitosis is a general term used to describe the bad breath coming out of the oral cavity. Volatile Sulfur Compounds (VSCs) are a major component causes of halitosis, formed from the break down of protein substrate by gram-negative anaerobes such as Porphyromonas gingivalis, Tanerella forsythia, Fusobacterium nucleatum, Prevotella intermedia and Treponema denticola. Guava leaf (Psidium guajava Linn) contain high levels of quercetin compounds that can inhibit the growth of Porphyromonas gingivalis and Prevotella intermedia. This study aims to determine the effectiveness of 5% guava leaf (Psidium guajava linn) extract of white fruit variant to decrease levels of Volatile Sulfur Compounds (VSCs) in halitosis sufferers. This research method was pre-experimental which consists of 19 subjects. The guava leaf (Psidium guajava Linn) extract was made by maceration method and diluted with distiled water at 5% concentration. The levels of Volatile Sulfur Compounds (VSCs) were measured by breath checker before (pre test) and after (post test) treatment. Wilcoxon test showed that there was a significant difference between the levels of Volatile Sulfur Compounds (VSCs) before and after gargling with 5% guava leaf (Psidium guajava Linn) extract of white fruit variant (p&lt;0,05). The conclusion of this research was 5% guava leaf (Psidium guajava Linn) extract of white fruit variant effectively decreases levels of Volatile Sulfur Compounds (VSCs) in halitosis sufferers.