Antagonist enamel tooth wear produced by different dental ceramic systems: A systematic review and network meta-analysis of controlled clinical trials.

OBJECTIVES: The aim of this study was to evaluate the amount of enamel tooth wear induced by different antagonistic ceramic crown materials in the posterior area within a follow-up period up to 24 months in function. A network meta-analysis was performed to assess the effect of the materials on the mean vertical loss (MVL) of the antagonist enamel tooth surface. DATA: Main search terms used in combination: ceramic, dental materials, metal ceramic, tooth wear and dental enamel. SOURCES: An electronic search was conducted in PubMed/Medline, Embase, and Cochrane CENTRAL plus hand-searching. STUDY SELECTION: Eligibility criteria included clinical studies reporting on MVL on antagonist's tooth up to 24 months following the permanent crown placement. From a total of 5697 articles, 7 studies reporting on 261 crowns for 177 subjects with 3 ceramic materials (Lithium disilicate, metal-ceramic, monolithic zirconia) were included. Among all, metal-ceramic and zirconia caused significantly higher enamel tooth wear on antagonist teeth, representing 82.5 µm [54.4; 110.6]) and 40.1 µm [22.2; 58.0]) more MVL than natural teeth group. In contrast, lithium disilicate showed only 5.0 µm [-48.2; 58.1]) more MVL than occurs on opposing natural teeth. CONCLUSIONS: This systematic review demonstrated that prosthodontic ceramic materials produced significantly more antagonist enamel tooth wear than opposing natural enamel tooth wear, and ceramic material type was correlated to the degree of enamel tooth wear. Additional well-conducted, randomized controlled trials with homogeneous specimens are required due to inadequate sample size and number of the clinical studies included in the analyses. CLINICAL SIGNIFICANCE: The amount of wear caused by different restorative materials has a high influence on the antagonistic natural teeth and should therefore be evaluated intensively by the dentist.

Effect of finish line location and saliva contamination on the accuracy of crown finish line scanning.

PURPOSE: Intraoral scanners are used widely as an alternative to conventional impressions, but studies on the influence of finish line location and saliva contamination on scanning trueness are lacking. The purpose of this in vitro study was to evaluate the influence of finish line location and saliva contamination on the scanning trueness of crown finish lines. MATERIALS AND METHODS: Three ivorine teeth were prepared for all-ceramic crowns with finish lines placed equigingivally, 0.5 mm subgingivally, and 1.0 mm subgingivally. A single-cord technique was used for gingival retraction, and a total of 180 intraoral scans were made using two intraoral scanners (Emerald; Planmeca USA Inc., Hoffman Estates, IL, USA & Trios 3; 3Shape A/S, Copenhagen, Denmark). The prepared teeth were separated from the dentoform and scanned using the same intraoral scanners to create reference scans. All scans were imported to the design software (Dental System 2019; 3Shape A/S, Copenhagen, Denmark). After marking the finish lines of prepared teeth, intraoral scans were aligned to the reference scans for comparisons. Vertical and horizontal marginal discrepancies were measured at four different measuring points (buccal, lingual, mesial, and distal) and analyzed. Two-way ANOVA and Tukey HSD tests were used for statistical analysis (α = 0.05). RESULTS: The average vertical and horizontal discrepancies from various groups ranged from -33 to 440 µm. For both intraoral scanners, subgingival finish line groups showed greater vertical and horizontal discrepancies compared with equigingival finish line groups. Saliva contamination significantly increased both vertical and horizontal discrepancies for all finish line locations. The discrepancy increases due to saliva contamination were greater for the subgingival groups. CONCLUSIONS: Subgingival finish lines were not accurately captured using the intraoral scanners. The presence of saliva significantly reduced scanning trueness, and this was amplified when the finish lines were located subgingivally.

Facilitating In-House Mobile App Development Within Psychiatric Outpatient Services for Patients Diagnosed With Borderline Personality Disorder: Rapid Application Development Approach.

BACKGROUND: Mobile app development within mental health is often time- and resource-consuming, challenging the development of mobile apps for psychiatry. There is a continuum of software development methods ranging from linear (waterfall model) to continuous adaption (Scrum). Rapid application development (RAD) is a model that so far has not been applied to psychiatric settings and may have some advantages over other models. OBJECTIVE: This study aims to explore the utility of the RAD model in developing a mobile app for patients with borderline personality disorder (BPD) in a psychiatric outpatient setting. METHODS: The 4 phases of the RAD model: (1) requirements planning, (2) user design, (3) construction, and (4) cutover, were applied to develop a mobile app within psychiatric outpatient services for patients diagnosed with BPD. RESULTS: For the requirements planning phase, a short time frame was selected to minimize the time between product conceptualization and access within a clinical setting. Evidenced-based interactive content already developed was provided by current staff to enhance usability and trustworthiness. For the user design phase, activity with video themes and a discrete number of functions were used to improve the app functionality and graphical user interface. For the construction phase, close collaboration between clinicians, researchers, and software developers yielded a fully functional, in-house-developed app ready to be tested in clinical practice. For the cutover phase, the mobile app was tested successfully with a small number (n=5) of patients with a BPD. CONCLUSIONS: The RAD model could be meaningfully applied in a psychiatric setting to develop an app for BPD within a relatively short time period from conceptualization to implementation in the clinic. Short time frames and identifying a limited number of stakeholders with relevant skills in-house facilitated the use of this model. Despite some limitations, RAD could be a useful model in the development of apps for clinical populations to enable development and access to evidence-based technology.

Correction: Psychiatric Treatment Conducted via Telemedicine Versus In-Person Modality in Posttraumatic Stress Disorder, Mood Disorders, and Anxiety Disorders: Systematic Review and Meta-Analysis.

[This corrects the article DOI: 10.2196/44790.].

Trueness of 3-dimensionally printed complete arch implant analog casts.

STATEMENT OF PROBLEM: Although a completely digital workflow has numerous advantages, a physical definitive cast may be especially helpful for the accurate assembly of components of complex complete arch-fixed prostheses, the evaluation of esthetic and occlusion features, or prosthesis fabrication. Research on the accuracy of additive complete arch casts with implants positioned with a large anterior-posterior (A-P) spread is sparse. PURPOSE: The purpose of this in vitro study was to evaluate the trueness of complete arch 4-implant analog casts with a large A-P distribution fabricated with different 3-dimensional (3D) printers. MATERIAL AND METHODS: Ten systems were evaluated representing currently available printing technologies and materials for the additive fabrication of complete arch 4-implant analog casts and compared for deviations in the X-, Y-, and Z-axes from the master model scan (MMS), recorded in standard tessellation language (STL). The MMS was provided to the laboratory selected by the manufacturer, permitting them to create their specific cast with computer-aided design and computer-aided manufacture specific to a particular system, including analog receptacle offset settings. Laboratories fabricated N=10 casts and affixed analogs. A conventional splinted impression and stone cast (CON) was fabricated as a control. The casts were scanned with a precision laboratory scanner (D2000; 3Shape A/S), and files were imported into the Convince metrology software program (3Shape A/S) for comparison with the MMS for mean deviations in the X-, Y-, and Z- axes. A 2-way ANOVA and the Tukey HSD comparison tests were performed between system groups and the 4 implant locations (α=.05). Comparative color maps were used to determine dimensional changes of the edentulous ridges. RESULTS: For 2-dimensional deviations from the MMS in each of the 3 axes, the printer type, implant location, and interaction between those 2 variables were found to be statistically significant (P<.05). Comparisons among printers showed the smallest deviations for Asiga Pro 4K (ASG) and Stratasys Origin One (ORI) printers in both the X- and Y-axes and for CON in the Z-axis. For 3D deviations, comparison among printers indicated that ORI, SprintRay Pro55 S (SPR), and Ackuretta SOL (ACK) had the largest deviations, whereas CON and ASG showed the smallest deviations. Comparison color mapping demonstrates a disparity between printed model dimensional changes and implant analog positioning since the color maps of the casts' ridge crests were not in concordance with the results of the implant analog deviations. CONCLUSIONS: ASG, 3D Systems ProJet MJP 2500 Plus (MJP), 3D Systems NextDent 5100 (NEX), Stratasys J5 DentaJet (PJ5), Ivoclar PrograPrint PR5 (PR5), and Prodways ProMaker LD20 (PWY) were similar in terms of 3D deviations to the conventional stone cast control. Comparative color mapping showed the direction and quantity of the dimensional changes of the ridge crest frequently did not correlate with the 3D deviations of implant analog positioning. Implant analog insertion errors were predominantly responsible for analog position 3D deviations rather than the polymerization shrinkage of additive photopolymers.

Psychiatric Treatment Conducted via Telemedicine Versus In-Person Modality in Posttraumatic Stress Disorder, Mood Disorders, and Anxiety Disorders: Systematic Review and Meta-Analysis.

BACKGROUND: Telemedicine has played a vital role in providing psychiatric treatment to patients during the rapid transition of services during the COVID-19 pandemic. Furthermore, the use of telemedicine is expected to expand within the psychiatric field. The efficacy of telemedicine is well described in scientific literature. However, there is a need for a comprehensive quantitative review that analyzes and considers the different clinical outcomes and psychiatric diagnoses. OBJECTIVE: This paper aimed to assess whether individual psychiatric outpatient treatment for posttraumatic stress disorder, mood disorders, and anxiety disorders in adults using telemedicine is equivalent to in-person treatment. METHODS: A systematic search of randomized controlled trials was conducted using recognized databases for this review. Overall, 4 outcomes were assessed: treatment efficacy, levels of patient satisfaction, working alliance, and attrition rate. The inverse-variance method was used to summarize the effect size for each outcome. RESULTS: A total of 7414 records were identified, and 20 trials were included in the systematic review and meta-analysis. The trials included posttraumatic stress disorder (9 trials), depressive disorder (6 trials), a mix of different disorders (4 trials), and general anxiety disorder (1 trial). Overall, the analyses yielded evidence that telemedicine is comparable with in-person treatment regarding treatment efficacy (standardized mean difference -0.01, 95% CI -0.12 to 0.09; P=.84; I2=19%, 17 trials, n=1814), patient satisfaction mean difference (-0.66, 95% CI -1.60 to 0.28; P=.17; I2=44%, 6 trials, n=591), and attrition rates (risk ratio 1.07, 95% CI 0.94-1.21; P=.32; I2=0%, 20 trials, n=2804). The results also indicated that the working alliance between telemedicine and in-person modalities was comparable, but the heterogeneity was substantial to considerable (mean difference 0.95, 95% CI -0.47 to 2.38; P=.19; I2=75%, 6 trials, n=539). CONCLUSIONS: This meta-analysis provided new knowledge on individual telemedicine interventions that were considered equivalent to in-person treatment regarding efficacy, patient satisfaction, working alliance, and attrition rates across diagnoses. The certainty of the evidence regarding efficacy was rated as moderate. Furthermore, high-quality randomized controlled trials are needed to strengthen the evidence base for treatment provided via telemedicine in psychiatry, particularly for personality disorders and a range of anxiety disorders where there is a lack of studies. Individual patient data meta-analysis is suggested for future studies to personalize telemedicine. TRIAL REGISTRATION: PROSPERO International Prospective Register of Systematic Reviews CRD42021256357; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=256357.

Isolation of Bioactive Metabolites from Soil Derived Fungus-Aspergillus fumigatus.

Fungi produce numerous secondary metabolites with intriguing biological properties for the health, industrial, and agricultural sectors. Herein, we report the high-yield isolation of phenolic natural products, N-formyl-4-hydroxyphenyl-acetamide 1 (~117 mg/L) and atraric acid 2 (~18 mg/L), from the ethyl acetate extract of the soil-derived fungus, Aspergillus fumigatus. The structures of compounds 1 and 2 were elucidated through the detailed spectroscopic analysis of NMR and LCMS data. These compounds were assayed for their antimicrobial activities. It was observed that compounds 1 and 2 exhibited strong inhibition against a series of fungal strains but only weak antibacterial properties against multi-drug-resistant strains. More significantly, this is the first known instance of the isolation of atraric acid 2 from a non-lichen fungal strain. We suggest the optimization of this fungal strain may exhibit elevated production of compounds 1 and 2, potentially rendering it a valuable source for the industrial-scale production of these natural antimicrobial compounds. Further investigation is necessary to establish the veracity of this hypothesis.

Comparison of strength of milled and conventionally processed PMMA complete-arch implant-supported immediate interim fixed dental prostheses.

STATEMENT OF PROBLEM: A typical conversion process of a complete-arch immediate loading protocol entails preparing holes in a complete denture for connection to interim copings, which reduces the strength of the prosthesis. The excellent mechanical properties of milled polymethyl methacrylate (PMMA) disks may provide interim prostheses with improved strength. PURPOSE: The purpose of this in vitro study was to measure the flexural strength and failure load of simulated acrylic resin immediate implant-supported interim prostheses fabricated by conventional processing and computer-aided manufacturing. MATERIAL AND METHODS: A master patient model was created with an acrylic resin base and 2 BioHorizons Internal 4.5-mm-diameter implants placed with a 21.5-mm span and multiunit abutments (MUA) tightened to place. Two groups with different prosthodontic designs were used: one represented the standard fixed prosthesis with support at each end (noncantilever, NC), and the other group represented the cantilever portion of the prosthesis (cantilever, C). Two connection designs of prosthesis blocks to MUA abutments were evaluated: one with typical holes in the prosthesis for capturing interim copings and one with a low-profile coping. For the heat-processed PMMA groups (HP/NC and HP/C), wax patterns were milled, and heat-polymerized denture base PMMA prostheses were processed. The milled PMMA groups (M/NC and M/C) were milled from a tooth-shaded PMMA disk for the prosthesis blocks. The milled low-profile groups (Mlp/NC and Mlp/C) had identical dimensions except that connection to the low-profile coping was designed with a cement space and a narrow diameter screw access hole and was milled from a PMMA disk. The failure load (N) of the cantilever prostheses was recorded, and for NC groups, the 3-point flexural strength formula (MPa) was calculated. The Weibull modulus, characteristic strength, and summary statistics were computed, and the groups were statistically analyzed with ANOVA and the post hoc Tukey test (α=.05). RESULTS: The mean flexural strengths (MPa) were HP/NC=91.35 ±18.92; M/NC=143.94 ±36.79; Mlp/NC=117.06 ±13.86. Significant differences were found among groups (P<.001). Mean failure loads (N) and Weibull modulus (WM) of cantilever prosthesis strengths were for HP/C=512.66, WM=5.597; M/C=695.06, WM=4.875; Mlp/C=254.97, WM=1.797 (P<.001). CONCLUSIONS: Implant fixed interim structures milled from high-density PMMA blanks had a 35% higher flexural strength for both the standard prostheses and the cantilever prostheses than heat-processed denture base PMMA. The low-profile coping design was stronger than the heat-processed material, and the failure point was relocated from the lateral walls to the cervical margin area.

Unraveling usnic acid: a comparison of biosynthetic gene clusters between two reindeer lichen (Cladonia rangiferina and C. uncialis).

Lichenized fungi are known for their production of a diversity of secondary metabolites, many of which have broad biological and pharmacological applications. By far the most well-studied of these metabolites is usnic acid. While this metabolite has been well-known and researched for decades, the gene cluster responsible for its production was only recently identified from the species Cladonia uncialis. Usnic acid production varies considerably in the genus Cladonia, even among closely related taxa, and many species, such as C. rangiferina, have been inferred to be incapable of producing the metabolite based on analysis by thin-layer chromatography (TLC). We sequenced and examined the usnic acid biosynthetic gene clusters, or lack thereof, from four closely related Cladonia species (C. oricola, C. rangiferina, C. stygia, and C. subtenuis), and compare them against those of C. uncialis. We complement this comparison with tiered chemical profile analyses to confirm the presence or absence of usnic acid in select samples, using both HPLC and LC-MS. Despite long-standing reporting that C. rangiferina lacks the ability to produce usnic acid, we observed functional gene clusters from the species and detected usnic acid when extracts were examined by LC-MS. By contrast, C. stygia and C. oricola, have been previously described as lacking the ability to produce usnic acid, lacked the gene cluster entirely, and no usnic acid could be detected in C. oricola extracts via HPLC or LC-MS. This work suggests that chemical profiles attained through inexpensive and low-sensitivity methods like TLC may fail to detect low abundance metabolites that can be taxonomically informative. This study also bolsters understanding of the usnic acid gene cluster in lichens, revealing differences among domains of the polyketide synthase which may explain observed differences in expression. These results reinforce the need for comprehensive characterization of lichen secondary metabolite profiles with sensitive LC-MS methods.

Psychiatric treatment conducted via telemedicine versus in-person consultations in mood, anxiety and personality disorders: a protocol for a systematic review and meta-analysis.

INTRODUCTION: Major advancements in technology have led to considerations how telemedicine (TM) and other technology platforms can be meaningfully integrated in treatment for psychiatric disorders. The COVID-19 pandemic has placed a further focus on use of TM in psychiatry. Despite the widespread use of TM, little is known about its effect compared with traditional in-person (IP) consultation. The objective of this systematic review is to examine if individual psychiatric outpatient interventions for adults using TM are comparable to IP in terms of (1) psychopathology outcomes, (2) levels of patient satisfaction, (3) working alliance and (4) dropout from treatment. METHODS AND ANALYSIS: This review will only include randomised controlled trials for adult participants with mood disorders, anxiety or personality disorders. The primary outcome is psychopathology, and secondary outcomes include patient satisfaction, treatment alliance and dropout rate. Systematic searches were conducted in MEDLINE, APA PsycINFO, Embase, Web of Science and CINAHL. The inverse-variance method will be used to conduct the meta-analysis. Effect sizes will be calculated as standardised mean difference (Hedges' g) for the primary outcome, mean difference for patient satisfaction and working alliance, and risk ratio for the dropout rate. Effect sizes will be supplemented with 95% CI. We will calculate the I² statistic to quantify heterogeneity and Chi-square statistic (χ²) to test for heterogeneity for the primary outcome. Potential clinical and methodological heterogeneity moderators will be assessed in subgroup and sensitivity analysis. The risk of bias will be assessed by Cochrane Risk of Bias Tool V.2, and confidence in cumulative evidence will be assessed by Grading of Recommendations Assessment, Development and Evaluation. ETHICS AND DISSEMINATION: No ethical approval is required for this systematic review protocol. Data sets will be deposited in the Zenodo repository. The findings of this study will be published in a peer-review scientific journal. PROSPERO REGISTRATION NUMBER: CRD42021256357.

The isolation, purification and complete characterization of the diterpene forskolin from nutritional supplements.

Forskolin (1) is a diterpene found in the Coleus forskohlii plant that has been examined for its medical properties resulting from adenylyl cyclase activation. This article describes a straightforward purification method of 1 from commercially available weight loss capsules. In addition, there has been some ambiguity with respect to the use of the name 'forskolin' to describe 1 and related diterpenes, which this report serves to eliminate. Herein we detail the complete spectroscopic characterization of purified 1 as well as its single crystal X-ray structure.

Challenges of Using Resonance Frequency Analysis to Identify Stability of a Dental Implant Placed in the Mandible.

PURPOSE: This numerical study examined the efficacy and challenges of using resonance frequency analysis to identify the stability of implants placed in mandibles. The study also examined the feasibility of using angular stiffness as an alternative index to quantify dental implant stability in mandibles. MATERIALS AND METHODS: A finite element model consisting of a mandible, an implant, an abutment, and a bonding layer (between the implant and the mandible) was created in commercially available software ANSYS. The level of osseointegration was modeled by varying the stiffness of the bonding layer. Three sets of boundary conditions were imposed on the mandible: fixed, rotationally free, and rotationally restrained. Three implant locations were studied: central, premolar, and molar positions. An alternative abutment mimicking SmartPeg and eight different implant lengths were also included. A modal analysis and a static analysis were conducted to calculate resonance frequencies and angular stiffness, respectively. RESULTS: Two types of vibration modes were found. One was jawbone modes, for which the mandible deformed significantly but not the bonding layer. Resonance frequencies of the jawbone modes were not sensitive to the level of osseointegration. The other was implant modes, for which the bonding layer deformed significantly but not the mandible. Among multiple implant modes obtained, only one was trackable as the level of osseointegration increased. The resonance frequency of the trackable implant mode was very sensitive to the implant location as well as boundary conditions, but not as much to the level of osseointegration. In contrast, angular stiffness was sensitive to the level of osseointegration but not as much to boundary conditions. CONCLUSION: The efficacy of using resonance frequency analysis to quantify the stability of a dental implant is questionable. Its high sensitivity to implant locations and boundary conditions as well as its low sensitivity to the level of osseointegration cause huge uncertainties in correlating measured resonance frequencies to implant stability. Angular stiffness is a much more reliable indicator because of its high sensitivity to the level of osseointegration and low sensitivity to boundary conditions.

Effect of fluorescent and nonfluorescent glaze pastes on lithium disilicate pressed ceramic color at different thicknesses.

STATEMENT OF PROBLEM: Materials possessing fluorescent properties are assumed to emit sufficient visible light to change tooth color under daylight illumination. Fluorescent and nonfluorescent glaze pastes are available to finish the surface of a pressed lithium disilicate restoration. However, the effect of a fluorescent-glaze layer on the final color of the restoration remains unclear. PURPOSE: The purpose of this in vitro study was to measure the color dimensions of lithium disilicate glass-ceramic with different thicknesses and different surface treatments under daylight (D65) illumination conditions. MATERIAL AND METHODS: A total of 120 pressed lithium disilicate glass-ceramic disks were fabricated with 4 different thicknesses: 0.7, 1.2, 1.7, and 2.2 mm. In each thickness, 3 different subgroups were created based on the surface treatment performed (n=10): polished (NG), clear glaze (CG), and fluorescent glaze (FG). For the NG group, disks were polished with 180-, 320-, 600-, 800-, and 1400-grit SiC papers and a polishing machine. For the glazed groups, the CG and FG groups, the specimens were polished with 180-grit SiC papers and the same polishing machine. After the polishing sequence, the final thickness was verified in all groups by using digital calipers (0.5, 1.0, 1.5, and 2.0 mm). Additionally, 20 µL of clear glaze or fluorescent glaze was applied on the CG and FL groups by using an electronic positive displacement repeating pipette. The glaze layer was crystallized in a furnace according to the manufacturer recommendations. Color measurements in the CIELab coordinates were made with a spectrometer coupled to an integrating sphere and a standardized photography gray card as a background. Color difference (ΔE) values were calculated by using the CIE76 and CIEDE2000 formulas. The Shapiro-Wilk test revealed that the data were normally distributed. Two-way ANOVA and the Bonferroni test for multiple comparisons were used to analyze the data (α=.05). RESULTS: Statistically significant differences were found among the groups for the L∗, a∗, and b∗ values for the different ceramic thicknesses and surface finishing treatments evaluated (P<.001), except for the b∗ value between the FG and CG groups (P=.988). The L∗ value on the polished group was significantly higher than that on the glazed specimens, followed by the fluorescent-glazed and then by the clear-glazed specimens (P<.001). The ΔE values using the CIE76 formula varied from 0.87 to 2.76 among specimen groups and from 0.32 to 2.34 using the CIEDE2000 among the tested groups. CONCLUSIONS: Ceramic thickness and surface finishing treatment affected all color dimensions (L∗, a∗, and b∗ values) of lithium disilicate ceramic under daylight conditions. These differences resulted in a perceptible but acceptable color mismatch. The value (L∗ color dimension) of the lithium disilicate ceramic was higher on fluorescent-glazed than on not-fluorescent-glazed specimens.

Use of cyclic peptides to induce crystallization: case study with prolyl hydroxylase domain 2.

Crystallization is the bottleneck in macromolecular crystallography; even when a protein crystallises, crystal packing often influences ligand-binding and protein-protein interaction interfaces, which are the key points of interest for functional and drug discovery studies. The human hypoxia-inducible factor prolyl hydroxylase 2 (PHD2) readily crystallises as a homotrimer, but with a sterically blocked active site. We explored strategies aimed at altering PHD2 crystal packing by protein modification and molecules that bind at its active site and elsewhere. Following the observation that, despite weak inhibition/binding in solution, succinamic acid derivatives readily enable PHD2 crystallization, we explored methods to induce crystallization without active site binding. Cyclic peptides obtained via mRNA display bind PHD2 tightly away from the active site. They efficiently enable PHD2 crystallization in different forms, both with/without substrates, apparently by promoting oligomerization involving binding to the C-terminal region. Although our work involves a specific case study, together with those of others, the results suggest that mRNA display-derived cyclic peptides may be useful in challenging protein crystallization cases.

Characterization of a Type-2 Diacylglycerol Acyltransferase from Haematococcus pluvialis Reveals Possible Allostery of the Recombinant Enzyme.

Haematococcus pluvialis is a green microalga used in the algal biotechnology industry that can accumulate considerable amounts of storage triacylglycerol (TAG) and astaxanthin, which is a high-value carotenoid with strong antioxidant activity, under stress conditions. Diacylglycerol acyltransferase (DGAT) catalyzes the last step of the acyl-CoA-dependent TAG biosynthesis and appears to represent a bottleneck in algal TAG formation. In this study, putative H. pluvialis DGAT2 cDNA (HpDGAT2A, B, D and E) were identified from a transcriptome database and were subjected to sequence-based in silico analyses. The coding sequences of HpDGAT2B, D, and E were then isolated and characterized through heterologous expression in a TAG-deficient Saccharomyces cerevisiae strain H1246. The expression of HpDGAT2D allowed the recovery of TAG biosynthesis in this yeast mutant, and further in vitro enzymatic assays confirmed that the recombinant HpDGAT2D possessed strong DGAT activity. Interestingly, the recombinant HpDGAT2D displayed sigmoidal kinetics in response to increasing acyl-CoA concentrations, which has not been reported in plant or algal DGAT2 in previous studies.

Phenylacetyl Coenzyme A, Not Phenylacetic Acid, Attenuates CepIR-Regulated Virulence in Burkholderia cenocepacia.

During phenylalanine catabolism, phenylacetic acid (PAA) is converted to phenylacetyl coenzyme A (PAA-CoA) by a ligase, PaaK, and then PAA-CoA is epoxidized by a multicomponent monooxygenase, PaaABCDE, before further degradation through the tricarboxylic acid (TCA) cycle. In the opportunistic pathogen Burkholderia cenocepacia, loss of paaABCDE attenuates virulence factor expression, which is under the control of the LuxIR-like quorum sensing (QS) system, CepIR. To further investigate the link between CepIR-regulated virulence and PAA catabolism, we created knockout mutants of the first step of the pathway (PAA-CoA synthesis by PaaK) and characterized them in comparison to a paaABCDE mutant using liquid chromatography-tandem mass spectrometry (LC-MS/MS) and virulence assays. We found that while loss of PaaABCDE decreased virulence, deletion of the paaK genes resulted in a more virulent phenotype than that of the wild-type strain. Deletion of either paaK or paaABCDE led to higher levels of released PAA but no differences in levels of internal accumulation compared to the wild-type level. While we found no evidence of direct cepIR downregulation by PAA-CoA or PAA, a low-virulence cepR mutant reverted to a virulent phenotype upon removal of the paaK genes. On the other hand, removal of paaABCDE in the cepR mutant did not impact its attenuated phenotype. Together, our results suggest an indirect role for PAA-CoA in suppressing B. cenocepacia CepIR-activated virulence.IMPORTANCE The opportunistic pathogen Burkholderia cenocepacia uses a chemical signal process called quorum sensing (QS) to produce virulence factors. In B. cenocepacia, QS relies on the presence of the transcriptional regulator CepR which, upon binding QS signal molecules, activates virulence. In this work, we found that even in the absence of CepR, B. cenocepacia can elicit a pathogenic response if phenylacetyl-CoA, an intermediate of the phenylacetic acid degradation pathway, is not produced. Instead, accumulation of phenylacetyl-CoA appears to attenuate pathogenicity. Therefore, we have discovered that it is possible to trigger virulence in the absence of CepR, challenging the classical view of activation of virulence by this QS mechanism. Our work provides new insight into the relationship between metabolism and virulence in opportunistic bacteria. We propose that in the event that QS signaling molecules cannot accumulate to trigger a pathogenic response, a metabolic signal can still activate virulence in B. cenocepacia.

Synthesis and antibiotic activity of novel acylated phloroglucinol compounds against methicillin-resistant Staphylococcus aureus.

The rise in antibiotic resistance among pathogenic microorganisms has created an imbalance in the drugs available for treatment, in part due to the slow development of new antibiotics. Cystic fibrosis (CF) patients are highly susceptible to antibiotic-resistant pathogens, including methicillin-resistant Staphylococcus aureus (MRSA). Phloroglucinols and related polyketide natural products have demonstrated antimicrobial activity against a number of Gram-positive bacteria including S. aureus. In this study, we investigated a series of acylated phloroglucinol derivatives to determine their potential as lead compounds for the design of novel therapeutics. To assess the activity of these compounds, we determined the minimum inhibitory and bactericidal concentration (MIC and MBC, respectively), the minimum biofilm inhibitory and biofilm eradication concentration (MBIC and MBEC, respectively), and evaluated hemolytic activity, as well as their interaction with clinically relevant antibiotics. Of the 12 compounds tested against MRSA and methicillin-susceptible strains, four showed MIC values ranging from 0.125 to 8 µg ml-1 and all of them were bactericidal. However, none of the compounds were able to eradicate biofilms at the concentrations tested. Three of the four did not display hemolytic activity under the conditions tested. Further studies on the interactions of these compounds with clinically relevant antibiotics showed that phlorodipropanophenone displayed synergistic activity when paired with doxycycline. Our results suggest that these acylated phloroglucinols have potential for being further investigated as antibacterial leads.

A Critique of Resonance Frequency Analysis and a Novel Method for Quantifying Dental Implant Stability in Vitro.

PURPOSE: This study assessed the ability of resonance frequency measurements to differentiate the stability of implants with different lengths and diameters, and in different densities of bone. Another objective was to identify an alternative parameter capable of quantifying dental implant stability, thus facilitating greater sensitivity for efficacious detection of compromised or failing implants. MATERIALS AND METHODS: Implants of two different diameters (4 and 5 mm) and six different lengths were individually placed in synthetic bone blocks of three different densities (15, 40/20, and 40 pounds per cubic foot) in combination with two different abutments (short and tall) to evaluate their stability. Resonance frequency measurements were obtained via Osstell ISQ and experimental modal analysis (EMA). The resonance frequency measurements were further confirmed via finite element analysis (FEA) using commercially available software ANSYS. RESULTS: Resonance frequencies measured via Osstell ISQ and EMA did not change with respect to the length of the implants. The FEA also confirmed the measured results. FEA simulations further indicated that angular stiffness at the neck of the implant (ie, the base of the abutment) varied considerably with respect to the implant length and diameter. Moreover, the calculated angular stiffness was independent of the type of abutment used. CONCLUSION: The results obtained from resonance frequency analyses did not accurately represent dental implant stability. Changes to implant length and diameter did not affect resonance frequencies. In contrast, angular stiffness at the neck of the implant represented a superior index for quantifying dental implant stability. It not only successfully differentiated stability of implants of both varying lengths and diameters, but also produced quantitative data that was independent of the type of abutments used.

A comprehensive catalogue of polyketide synthase gene clusters in lichenizing fungi.

Lichens are fungi that form symbiotic partnerships with algae. Although lichens produce diverse polyketides, difficulties in establishing and maintaining lichen cultures have prohibited detailed studies of their biosynthetic pathways. Creative, albeit non-definitive, methods have been developed to assign function to biosynthetic gene clusters in lieu of techniques such as gene knockout and heterologous expressions that are commonly applied to easily cultivatable organisms. We review a total of 81 completely sequenced polyketide synthase (PKS) genes from lichenizing fungi, comprising to our best efforts all complete and reported PKS genes in lichenizing fungi to date. This review provides an overview of the approaches used to locate and sequence PKS genes in lichen genomes, current approaches to assign function to lichen PKS gene clusters, and what polyketides are proposed to be biosynthesized by these PKS. We conclude with remarks on prospects for genomics-based natural products discovery in lichens. We hope that this review will serve as a guide to ongoing research efforts on polyketide biosynthesis in lichenizing fungi.

Accuracy of 3-dimensional computer-aided manufactured single-tooth implant definitive casts.

STATEMENT OF PROBLEM: The integration of the digital workflow into routine prosthodontic practice for single-tooth implant surgery and fixed prosthesis fabrication has occurred at a remarkable pace in the last 5 years. With the greater demands of esthetics and precision, the definitive implant analog cast must ensure accurate implant positioning as well as an accurate relationship to adjacent teeth. PURPOSE: The purpose of this in vitro study was to evaluate the accuracy of the 3-dimensional (3D) implant position of definitive casts produced by 3D printing and analog technology. MATERIAL AND METHODS: A master patient model was created from a dentate typodont. The maxillary left central incisor was removed, and a Straumann RC implant was positioned for a screw-retained prosthesis. A laboratory scanner with an accuracy of 5 µm was used for all scanning. A scanbody was connected to the master model implant and scanned to create a master patient file, which served as the control master patient for all comparisons. The two 3D printing systems used for this study were the Statasys Objet500 (group OBJ), an industrial Polyjet production system, and the Formlabs Formlab 2 (group FORM), a budget SLA Vat system. In addition, a conventional gypsum cast (group GYP) with an implant analog was made with elastomeric impression material. With a sample size of 10 per group, each gypsum cast and 2 printed group casts were scanned with the D2000 laboratory scanner 5 times per cast. Convince software (3Shape) was used for 3D analysis to calculate accuracy. The following variables were measured: implant analog vertical displacement, horizontal displacement of implant platform and apex, degree of tilting in the vertical axis, and rotational position change around the vertical axis. Means and standard deviations were calculated for trueness. One-way ANOVA and the post hoc t test with Bonferroni correction were used to investigate any significant differences among the experimental groups (α=.05). RESULTS: For vertical displacement of the implant body, group OBJ had the lowest value of -30 ±24 µm. The values obtained for OBJ and FORM were significantly different from that obtained for GYP (P<.05). For horizontal displacement of the implant shoulder, Group OBJ had the lowest value, 85 ±12 µm, and the difference among these groups was significantly different (P<.05). The value for horizontal displacement of the implant apex was 123 ±25 µm for group OBJ and not significantly different from that obtained for group GYP (136 ±40 µm) but significantly different from that obtained for group FORM (326 ±54 µm). Also, the analysis of implant body tilting in the vertical axis showed significant differences between the values obtained for groups GYP and OBJ and between the values obtained for groups OBJ and FORM. With regard to implant rotational position change around the vertical axis, the values obtained for the gypsum cast and group FORM were not statistically different from those obtained for the master patient control model (P>.05). However, the implant orientation of group OBJ was significantly different from the orientation of groups GYP and FORM (P<.05). The actual clinical relevance of these printing system discrepancies is yet to be determined because the level of clinical acceptable discrepancy in the x, y, and z vectors is still undefined. CONCLUSIONS: This study showed statistically significant differences in accuracy among the implant analog cast fabrication systems; however; the level of clinical acceptable discrepancy is still undefined. Although further research is needed, this study supports the conclusion that the Polyjet industrial printing system was more accurate than the conventional implant analog gypsum cast.