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Osteoporosis is a prevalent bone condition with adverse effects observed in patients undergoing long-term glucocorticoid therapy, resulting in bone demineralization and tissue loss. There has been limited studies on the global response to dexamethasone in terms of comparing its expression profile to other common glucocorticoids during osteogenic differentiation. This study focused on the downregulated gene expression profile of glucocorticoid compounds; dexamethasone, budesonide, and fluticasone propionate, during osteogenic differentiation to elucidate the related target genes and pathways associated with the anti-osteoporotic potential of telomerase-immortalized human bone marrow-derived mesenchymal stem cells using a bioinformatics approach. Based on gene expression microarrays experiments and bioinformatics analysis, several key genes involved in the regulation of osteogenic differentiation and osteoporosis development in mesenchymal stem cells that were targeted by these specific glucocorticoids were determined. Network analysis using GeneCards, OMIM, and CTD databases were performed and osteoporosis-related genes were identified. LIMMA and moderated Welch test R packages were performed to determine significant downregulated differentially expressed genes for each glucocorticoid treatment. A total of 479 (dexamethasone), 84 (budesonide), and 889 (fluticasone propionate) differentially expressed genes were identified for each glucocorticoid, of which 35 common genes overlapped. Enrichment pathway analysis was conducted using Metascape, and protein-protein interaction networks were constructed using the STRING database and Cytoscape software to determine potential target genes involved with osteoporosis. Enrichment pathway analysis revealed genes involved in 3 Reactome pathways namely cytokine signaling in immune system, immune system and the interferon alpha/beta signaling pathways and identified 10 hub genes based on the PPI network to determine potential target pathways associated with osteoporosis. These findings provide preliminary insights into the relationship between the key target genes of dexamethasone, budesonide, and fluticasone propionate, and the pathways associated with regulated osteoporosis metabolism during osteogenic differentiation.

Fasciolosis is a zoonotic infection and is considered a developing deserted tropical illness threatening ruminant productivity and causing financial losses. Herein, we applied immunoinformatics and biophysics studies to develop an epitopes vaccine against Fasciola hepatica using glutathione transferase and Cathepsin L-like proteinase as possible vaccine candidates. Using the selected proteins, B- and T-cell epitopes were predicted. After epitopes prediction, the epitopes were clarified over immunoinformatics screening, and only five epitopes, EFGRWQQEKCTIDLD, RRNIWEKNVKHIQEH, FKAKYLTEMSRASDI, TDMTFEEFKAKYLTE, and YTAVEGQCR were selected for vaccine construction; selected epitopes were linked with the help of a GPGPG linker and attached with an adjuvant through another linker, EAAAK linker. Cholera toxin B subunit was used as an adjuvant. The ExPASy ProtParam tool server predicted 234 amino acids, 25.86257 kDa molecular weight, 8.54 theoretical pI, 36.86 instability index, and −0.424 grand average of hydropathicity. Molecular docking analysis predicted that the vaccine could activate the immune system against F. hepatica. We calculated negative binding energy values. A biophysics study, likely molecular docking molecular dynamic simulation, further validated the docking results. In molecular dynamic simulation analysis, the top hit docked compounds with the lowest binding energy values were subjected to MD simulation; the simulation analysis showed that the vaccine and immune cell receptors are stable and can activate the immune system. MMGBSA of −146.27 net energy (kcal/mol) was calculated for the vaccine–TLR2 complex, while vaccine–TLR4 of −148.11 net energy (kcal/mol) was estimated. Furthermore, the C-ImmSim bioinformatics tool predicted that the vaccine construct can activate the immune system against F. hepatica, eradicate the infection caused by F. hepatica, and reduce financial losses that need to be spent while protecting against infections of F. hepatica. The computational immune simulation unveils that the vaccine model can activate the immune system against F. hepatica; hence, the experimental scientist can validate the finding accomplished through computational approaches.

Pseudomonas aeruginosa is a multidrug-resistant pathogen known for chronic infections, mainly due to biofilm formation. This study aimed to explore the potential repurposing of 5-fluorouracil (5-FU), an anticancer drug, to treat P. aeruginosa infections. Firstly, we investigated the inhibitory effects of 5-FU on bacterial growth using the microdilution method. Secondly, the impact of 5-FU on biofilm formation and disassembly was assessed via biofilm biomass measurements with the crystal violet staining method and confocal microscopy analyses. Lastly, the potential synergy between 5-FU and the antibiotics gentamicin and meropenem was evaluated using a checkerboard assay. Results revealed that 5-FU inhibited bacterial growth in a dose-dependent manner, with 100% inhibition observed at concentrations of 25 µg/mL and higher. Also, 70% and 100% reductions in biofilm biomass were demonstrated at concentrations of 12 and 100 µg/mL, respectively. Controversy, these higher concentrations unexpectedly increased biofilm biomass in pre-formed biofilms. Synergistic interactions were observed between 5-FU and gentamicin in both growth inhibition (FICI 0.31) and biofilm inhibition (ZIP 14.1), while no synergy was found with meropenem. These findings highlight the potential of 5-FU as an adjunctive therapy for P. aeruginosa infections, especially in combination with gentamicin. However, further research is required to address 5-FU limitations against mature biofilms.

Pseudomonas aeruginosa, a nosocomial pathogen, has strong biofilm capabilities, representing the main source of infection in the human body. Repurposing existing drugs has been explored as an alternative strategy to combat emerging antibiotic-resistant pathogens. Fingolimod hydrochloride (FTY720), an immunomodulatory drug for multiple sclerosis, has shown promising antimicrobial effects against some ESKAPE pathogens. Therefore, the effects of FTY720 on the biofilm capabilities of Pseudomonas aeruginosa were investigated in this study. It was determined that FTY720 inhibited the growth of P. aeruginosa PAO1 at 100 µM. The significant reduction in PAO1 cell viability was observed to be dose-dependent. Additional cytotoxicity analysis on human cell lines showed that FTY720 significantly reduced viabilities at sub-inhibitory concentrations of 25–50 µM. Microtiter assays and confocal analysis confirmed reductions in biofilm mass and thickness and the cell survivability ratio in the presence of FTY720. Similarly, virulence production and biofilm-related gene expression (rhlA, rhlB, pilA, pilI, fliC, fliD and algR) were determined. The results demonstrate that pigment production was affected and quantitative real-time PCR analysis showed a variable degree of reduced gene expression in response to FTY720 at 12.5–50 µM. These findings suggest that FTY720 could be repurposed as an alternative antibiofilm agent against Pseudomonas aeruginosa.

Background: Saudi Arabia has an overall smoking rate of 15.9%. The link between smoking and periodontal disease has been studied extensively. It is possible for human gingival fibroblasts to accumulate nicotine intracellularly over a period of four hours. Additionally, unmetabolized nicotine is released into the environment. Tobacco presence can impair tissue inflammation, wound healing, and organ development. To counterbalance tobacco toxins, vitamin C has been added to a variety of products. Aim: This study aims to analyze the RNA expression of antioxidant, anti-inflammatory, and wound healing proteins in human gingival fibroblasts from smokers and nonsmokers using polymerase chain reaction. Materials and Methods: hGFs were extracted from clinically healthy periodontium sites of adult male subjects. Both heavy cigarette smokers and never-smokers participated as subjects. Cells were cultured and subcultured in supplemented growth medium. Vitamin C was inducted in the medium at the experimental 6th passage. RNA expression analysis (qRT-PCR) was performed to analyze adhesion, proliferation, and extracellular matrix expression. Results: The results revealed marked expression of a wound healing gene (VEGF-A) in never-smokers (p value = 0.016). GPX3 and SOD3 represent antioxidants that are highly expressed in treated never-smoker cells. SOD2 significantly increased (p value = 0.016) in smokers after vitamin C exposure. The anti-inflammatory markers IL-6 and IL-8 were lower among smokers than among nonsmokers (p

Background: Porphyromonas gingivalis (P. gingivalis) is viewed as a keystone microorganism in the pathogenesis of periodontal and peri-implant diseases. Hyaluronic acid (HA) is believed to exert antimicrobial activity. The aim of this study is to assess the in-vitro growth and biofilm formation of P. gingivalis under HA and compare the effect of HA to that of azithromycin (AZM) and chlorhexidine (CHX). Materials and methods: In each material, the minimum inhibitory concentration (MIC), 50% MIC, 25% MIC, and 12.5% MIC were tested. The growth of P. gingivalis was evaluated by absorbance spectrophotometry after 48 h. A biofilm inhibition assay was performed on a 72-hour culture by washing planktonic bacterial cells, fixing and staining adherent cells, and measuring the variation in stain concentrations relative to the untreated control using absorbance spectrophotometry. Results: The results show that the overall growth of P. gingivalis after 48 h was 0.048 ± 0.030, 0.008 ± 0.013, and 0.073 ± 0.071 under HA, AZM, and CHX, respectively, while the untreated control reached 0.236 ± 0.039. HA was also able to significantly reduce the biofilm formation of P. gingivalis by 64.30 % ± 22.39, while AZM and CHX reduced biofilm formation by 91.16 %±12.58 and 88.35 %±17.11, respectively. Conclusions: High molecular-weight HA significantly inhibited the growth of P. gingivalis. The overall effect of HA on the growth of P. gingivalis was similar to that of CHX but less than that of AZM. HA was also able to significantly reduce the biofilm formation of P. gingivalis. However, the ability of HA to prevent the biofilm formation of P. gingivalis was generally less than that of both AZM and CHX.

The LuxS quorum sensing system is considered as the main system that most of the oral bacteria use to communicate in order to create biofilms. Here we identified 11 of the most important biofilm formers that utilize the LuxS system and presented current and recent information regarding this system. Though different bacterial species are able to communicate thorough the LuxS system, it was also found that cross kingdom communication can occur between bacteria and fungi and bacteria and epithelial cells. Immune response also plays and important role in mitigating the effects of biofilms. Here we identified 6 of the most important molecules that are involved in the immune response to biofilms. These immune molecules maintain the stability in the oral cavity by preventing bacteria from overwhelming the space and simultaneously minimizing the immune response in order not to cause tissue damage. Here we also discuss current research being done in order to maintain the balance in the oral cavity via inhibiting biofilm formation without eradicating oral bacteria in order to prevent the overgrowth of other organisms such as Candida albicans. One approach being used is inhibiting AI-2 intermediates which leads to lack of quorum sensing communication between bacteria through the use of intermediate analogues. Another approach that found success is the utilization of D forms of sugars where D-ribose and D-galactose have been proven to inhibit the LuxS system and subsequently preventing the process of quorum sensing leading to the reduction in biofilm formation.

Objectives: Finding alternative methods to overcome antibiotic resistance in the medically important bacterium Pseudomonas aeruginosa has become increasingly vital as antibiotic resistance becomes more difficult to overcome. DNA synthesis inhibition is a strategy that has been used to inhibit cancer cells from proliferating by using pyrimidine analogues. Gateway site-directed mutagenesis is an effective way to create precise knockouts which creates good models to understand the relationship between biochemical pathways and the physiology of the organism. This article demonstrates the effect of pyrimidine synthesis inhibition on the motility virulence and physiology of P. aeruginosa. Methods: Wild type Pseudomonas aeruginosa (PA01) was genetically modified using gateway cloning technology to inhibit the pyrimidine synthesis pathway through the complete knockout of the pyrE gene. The mutant strain was compared to the wild type PA01 in terms of its twitching, swarming and swimming motility forms and biofilm formation abilities. In addition to that, the production of the bacterial surfactant, rhamnolipids, was also measured. Results and conclusions: The inhibition of the pyrimidine synthesis pathway resulted in significant reduction in motility and biofilm capabilities, despite complementing the mutation with uracil to bypass the mutation. Inhibition of the pyrimidine synthesis pathway is thus an effective way to reduce the virulence of Pseudomonas aeruginosa. Even though the bacterium is able to acquire pyrimidines from its surrounding, it was not sufficient enough to overcome the effects of the mutation.

The axon initial segment (AIS), the site of action potential initiation in neurons, is a critical determinant of neuronal excitability. Growing evidence indicates that appropriate recruitment of the AIS macrocomplex is essential for synchronized firing. However, disruption of the AIS structure is linked to the etiology of multiple disorders, including autism spectrum disorder (ASD), a condition characterized by deficits in social communication, stereotyped behaviors, and very limited interests. To date, a complete understanding of the molecular components that underlie the AIS in ASD has remained elusive. In this research, we examined the AIS structure in a BTBR T+Itpr3tf/J mouse model (BTBR), a valid model that exhibits behavioral, electrical, and molecular features of autism, and compared this to the C57BL/6J wild-type control mouse. Using Western blot studies and high-resolution confocal microscopy in the prefrontal frontal cortex (PFC), our data indicate disrupted expression of different isoforms of the voltage-gated sodium channels (NaV) at the AIS, whereas other components of AIS such as ankyrin-G and fibroblast growth factor 14 (FGF14) and contactin-associated protein 1 (Caspr) in BTBR were comparable to those in wild-type control mice. A Western blot assay showed that BTBR mice exhibited a marked increase in different sodium channel isoforms in the PFC compared to wild-type mice. Our results provide potential evidence for previously undescribed mechanisms that may play a role in the pathogenesis of autistic-like phenotypes in BTBR mice.

The aim of this study was to evaluate the regeneration of bone defects created in the femoral condyle of osteoporotic rats, following intravenous (IV) zoledronate (ZA) treatment in three settings: pre-bone grafting (ZA-Pre), post-bone grafting (ZA-Post), and pre- plus post-bone grafting (ZA-Pre+Post). Twenty-four female Wistar rats were ovariectomized (OVX). After 12 weeks, bone defects were created in the left femoral condyle. All defects were grafted with a particulate inorganic cancellous bovine bone substitute. ZA (0.04 mg/kg, weekly) was administered to six rats 4 weeks pre-bone graft placement. To another six rats, ZA was given post-bone graft placement creation and continued for 6 weeks. Additional six rats received ZA treatment pre- and post-bone graft placement. Control animals received weekly saline intravenous injections. At 6 weeks post-bone graft placement, samples were retrieved for histological evaluation of the bone area percentage (BA%) and remaining bone graft percentage (RBG%). BA% for ZA-Pre (50.1 ± 3.5%) and ZA-Post (49.2 ± 8.2%) rats was significantly increased compared to that of the controls (35.4 ± 5.4%, p-value 0.031 and 0.043, respectively). In contrast, ZA-Pre+Post rats (40.7 ± 16.0%) showed similar BA% compared to saline controls (p = 0.663). For RBG%, all experimental groups showed similar results ranging from 36.3 to 47.1%. Our data indicate that pre- or post-surgical systemic IV administration of ZA improves the regeneration of bone defects grafted with inorganic cancellous bovine-bone particles in osteoporotic bone conditions. However, no favorable effect on bone repair was seen for continued pre- plus post-surgical ZA treatment.

The installation of dental implants has become a common treatment for edentulous patients. However, concern exists about the influence of osteoporosis on the final implant success. This study evaluated whether an ovariectomy (OVX)-induced osteoporotic condition, induced eight weeks postimplantation in a rat femoral condyle, influences the bone response to already-integrated implants. The implants were inserted in the femoral condyle of 16 female Wistar rats. Eight weeks postimplantation, rats were randomly ovariectomized (OVX) or sham-operated (SHAM). Fourteen weeks later, animals were sacrificed, and implants were used for histological and histomorphometric analyses. A significant reduction in the quantity and quality of trabecular bone around dental implants existed in OVX rats in comparison to the SHAM group. For histomorphometric analysis, the bone area (BA%) showed a significant difference between OVX (34.2 ± 4.3) and SHAM (52.6 ± 12.7) groups (p < 0.05). Bone–implant contact (BIC%) revealed significantly lower values for all implants in OVX (42.5 ± 20.4) versus SHAM (59.0 ± 19.0) rats. Therefore, induction of an osteoporotic condition eight weeks postimplantation in a rat model negatively affects the amount of bone present in close vicinity to bone implants.

To evaluate peri-implant bone formation following single or combined systemic administration of alendronate and simvastatin in healthy and osteoporotic rats, eighty female Wistar rats were ovariectomized (n = 40) or sham-operated (n = 40). At six weeks, implants were placed in femoral condyles. Then, ovariectomized (OVX) and sham-operated (SHAM) animals received daily subcutaneous alendronate (50 µg/kg), simvastatin (5 mg/kg), or both, for three weeks. Control animals received subcutaneous saline. Thereafter, specimens were retrieved for biomechanical testing, histological evaluation, and bone area (BA%) and bone-to-implant contact (BIC%). In healthy and osteoporotic rats, similar (p > 0.05) push-out values were observed for all groups. For BA% analysis, control rats showed similar results for OVX (9.2% ± 2.4%) and SHAM (11.1% ± 3.5%) animals. In contrast, single or combined drug therapy significantly increased BA% compared to controls in both healthy and osteoporotic conditions (p < 0.05). In osteoporotic conditions, alendronate alone showed a superior effect on BA% compared to simvastatin alone, or their combination. Systemic alendronate, simvastatin, or both showed a similar BIC% compared to controls (p > 0.05). The present study demonstrates that single or combined systemic alendronate and simvastatin increases bone formation around implants (i.e., distance osteogenesis) in healthy and osteoporotic bone conditions. However, these drugs showed no beneficial effect on direct bone-to-implant contact or implant fixation.

The aim of this in vivo study was to evaluate the efficacy of biphasic calcium phosphate (Maxresorb®, BCP) used in combination with hyaluronic acid (Hyadent®, HyA) gel for regeneration of osseous defects in a rat model. Bilateral femoral condylar bone defects (3 mm diameter and 3 mm depth) were created in 40 male Wistar rats. The defects were grafted as group I (BCP only), group II (BCP + HyA), group III (HyA only), and group IV (empty control). At four weeks and 10 weeks, the bone specimens were evaluated using histological and histomorphometrical analyses to identify the newly formed bone area (NF-BA (%)), as well as the remaining BCP particles (R-BCP (%)). Light microscopic examination indicated the absence of an inflammatory reaction within the bone defects after four weeks or 10 weeks of implantation. Significant new bone regeneration was present in the bone defects grafted with BCP or BCP + HyA biomaterials, as early as four weeks, compared to control groups. The addition of HyA to BCP did not significantly improve bone regeneration at four weeks or 10 weeks. Nevertheless, its role in bone healing and regeneration warrants further investigation.

Poly(2‑(tert-butylamino)ethyl methacrylate) brushes (PTBAEMA) are grown from mesoporous silica nanoparticles via surface-initiated atom transfer radical polymerization (SI-ATRP). Linear PTBAEMA brushes are protonated and highly swollen at low pH; brushes are collapsed at pH higher than 7.7 due to deprotonation, as determined by dynamic light scattering (DLS). Quaternization of these brushes is conducted using 2-iodoethanol in alkali media. DLS measurement of nanoparticles shows that surface-confined quaternization occurs and produces pH-responsive brushes with a hydrophobic upper surface. Variation of the 2-iodoethanol reaction time enables the mean degree of surface quaternization. The pH-responsive behaviour of quaternized PTBEAMA brushes at 1 h reaction time indicates low degrees of surface quaternization, dictated by the spatial location of 2-iodoethanol. Almost uniformly quaternized brushes prepared when the conducted for 3 h and became less swollen at low pH than brushes that conducted for 1 h. The intensity of the C − C − O component (286.5 eV) in the C1s X-ray photoelectron spectrum increased, suggesting that the reaction with iodoethanol was successful occurred.

Objective: To evaluate the adhesion of Streptococcus mutans (S. mutans) and related surface properties of ion-releasing resin-based composite (RBC) restorative materials., Methods: Two ion-releasing RBCs, Activa (ACT) and Cention-N (CN), were compared to a conventional RBC (Z350) and a resin-modified glass ionomer cement (Fuji-II-LC). Ten disk-shaped specimens were fabricated for each material (n = 40). After standardized surface polishing procedure, the surface properties of the specimens were evaluated using surface roughness measurements by a profilometer and hydrophobicity using water contact angle measurements. To assess bacterial adhesion, the number of S. mutans bacteria was calculated from colony-forming units (CFU). Confocal laser scanning microscope analysis was done for qualitative & quantitative assessment. The data were analyzed using One-way ANOVA followed by Tukey's post-hoc test to compare the mean values of surface roughness, water contact angle and CFU values. To compare the mean dead cell percentage Kruskal-Wallis rank test and Conover test were used. A p-value of ≤ 0.05 was used to report the statistical significance., Results: Z350 and ACT had the smoothest surfaces, followed by CN, and the roughest surface was seen in FUJI-II-LC. The lowest water contact angles were seen in CN, and Z350, and the highest were in ACT. S. mutans counts were the highest in ACT and the lowest in Z350 and CN. CN and Fuji-II-LC registered the highest percentage of dead bacterial cells, while the lowest were in ACT., Significance: Surface properties did not significantly influence bacterial adhesion. More S. mutans bacteria accumulated on ACT than on the nanofilled composite and on CN. CN had antibacterial effects against Streptococcus mutans biofilms., Competing Interests: Declaration of Competing Interest The authors declare that they have no conflict of interest, and there has been no significant financial interest in any company or any products mentioned in this manuscript that could have influenced the outcome., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Dental implants with surface-porous designs have been recently developed. Clinically, peri-implant bone grafting is expected to promote early osseointegration and bone ingrowth when applied with surface-porous dental implants in challenging conditions. The aim of this study was to comparatively analyze peri-implant bone healing around solid implants and surface-porous implants with and without peri-implant bone grafting, using biomechanical and histomorphometrical assessment in a goat iliac bone model. A total of 36 implants (4.1 mm wide, 11.5 mm long) divided into three groups, solid titanium implant (STI; n = 12), porous titanium implants (PTI; n = 12) and PTI with peri-implant bone grafting using biphasic calcium phosphate granules (PTI + BCP; n = 12), were placed bilaterally in the iliac crests of six goats. The goats were sacrificed seven weeks post-operatively and then subjected to biomechanical ( n = 6 per group) and histomorphometrical ( n = 6 per group) assessment. The biomechanical assessment revealed no significant differences between the three types of implants. Although the peri-implant bone-area (PIBA%) measured by histomorphometry (STI: 8.63 ± 3.93%, PTI: 9.89 ± 3.69%, PTI + BCP: 9.28 ± 2.61%) was similar for the three experimental groups, the percentage of new bone growth area (BGA%) inside the porous implant portion was significantly higher ( p < 0.05) in the PTI group (10.67 ± 4.61%) compared to the PTI + BCP group (6.50 ± 6.53%). These data demonstrate that peri-implant bone grafting around surface-porous dental implants does not significantly accelerate early osseointegration and bone ingrowth.

Depression is a common psychiatric disorder that has been poorly understood. Consequently, current antidepressant agents have clinical limitations. Until today, most have exhibited the slow onset of therapeutic action and, more importantly, their effect on remission has been minimal. Thus, the need to find new forms of therapeutic intervention is urgent. The inflammation hypothesis of depression is widely acknowledged and is one that theories the relationship between the function of the immune system and its contribution to the neurobiology of depression. In this research, we utilized an environmental isolation (EI) approach as a valid animal model of depression, employing biochemical, molecular, and behavioral studies. The aim was to investigate the anti-inflammatory effect of etanercept, a tumor necrosis factor-α inhibitor on a toll-like receptor 7 (TLR 7) signaling pathway in a depressive rat model, and compare these actions to fluoxetine, a standard antidepressant agent. The behavioral analysis indicates that depression-related symptoms are reduced after acute administration of fluoxetine and, to a lesser extent, etanercept, and are prevented by enriched environment (EE) housing conditions. Experimental studies were conducted by evaluating immobility time in the force swim test and pleasant feeling in the sucrose preference test. The mRNA expression of the TLR 7 pathway in the hippocampus showed that TLR 7, MYD88, and TRAF6 were elevated in isolated rats compared to the standard group, and that acute treatment with an antidepressant and anti-inflammatory drugs reversed these effects. This research indicates that stressful events have an impact on behavioral well-being, TLR7 gene expression, and the TLR7 pathway. We also found that peripheral administration of etanercept reduces depressive-like behaviour in isolated rats: this could be due to the indirect modulation of the TLR7 pathway and other TLRs in the brain. Furthermore, fluoxetine treatment reversed depressive-like behaviour and molecularly modulated the expression of TLR7, suggesting that fluoxetine exerts antidepressant effects partially by modulating the TLR7 signaling pathway., Competing Interests: The authors have declared that no competing interests exist.

This study assessed the antibacterial activity of BioRoot RCS in comparison with that of the Totalfill BC and AH Plus sealers against Enterococcus faecalis biofilms in dentinal tubules using confocal laser-scanning microscopy. Sixty-six root dentin halves were prepared and sterilized. Three sections were used to ensure sterilization. The remaining were inoculated with E. faecalis. Three specimens were examined to verify the viability of biofilms. The sixty specimens were randomly divided into four groups: AH Plus, BioRoot RCS, Totalfill BC sealer, and no sealer. The specimens were incubated for 1, 7, and 30 days. The specimens were stained and four corners of each disc were scanned. Statistical analysis was performed using two-way ANOVA and Tukey's post hoc test. Almost half of the bacteria were dead in BioRoot RCS group on day 1 and in Totalfill BC group on day 7. All sealers killed significantly more bacteria than the control after 30 days (P < .05). On day 7, Totalfill BC showed a significantly higher percentage of dead bacteria than BioRoot RCS (P < .05). On day 30, the BioRoot RCS group registered the highest percentage of dead cells (61.75%), which was significantly higher than the percentages of the AH Plus and Totalfill BC groups (P < .05). Calcium silicate-based root canal sealers exerted antimicrobial effects against E. faecalis biofilms. The antibacterial activity of BioRoot RCS was significantly higher than that of the Totalfill BC and AH Plus sealers after 30 days of exposure.

The impact of orotate accumulation in the medically important bacterium Pseudomonas aeruginosa was studied by deleting pyrE, the gene encoding orotate phosphoribosyltransferase and responsible for converting orotate into orotate monophosphate within the de novo pyrimidine synthesis pathway. The pyrE mutant accumulated orotate and exhibited decreased production of hemolysin, casein protease, and elastase. Feeding orotate at a concentration of 51.25 μM to the wild type, PAO1, likewise decreased production of these factors except for hemolysin, which was not affected. A significant increase in the pigments pyocyanin and pyoverdin was also observed. Pyocyanin increase in the pyrE mutant was heightened when the mutant was supplemented with orotate. Although pyoverdin production in the wild-type PAO1 was unaffected by orotate supplementation, a decrease in the mutant's production was observed when supplemented with orotate. These results indicate a significant reduction in virulence factor production in the pyrE mutant and reduction in some virulence factors in the wild type when supplemented with orotate.