GPR68 Senses Flow and Is Essential for Vascular Physiology.

Mechanotransduction plays a crucial role in vascular biology. One example of this is the local regulation of vascular resistance via flow-mediated dilation (FMD). Impairment of this process is a hallmark of endothelial dysfunction and a precursor to a wide array of vascular diseases, such as hypertension and atherosclerosis. Yet the molecules responsible for sensing flow (shear stress) within endothelial cells remain largely unknown. We designed a 384-well screening system that applies shear stress on cultured cells. We identified a mechanosensitive cell line that exhibits shear stress-activated calcium transients, screened a focused RNAi library, and identified GPR68 as necessary and sufficient for shear stress responses. GPR68 is expressed in endothelial cells of small-diameter (resistance) arteries. Importantly, Gpr68-deficient mice display markedly impaired acute FMD and chronic flow-mediated outward remodeling in mesenteric arterioles. Therefore, GPR68 is an essential flow sensor in arteriolar endothelium and is a critical signaling component in cardiovascular pathophysiology.

Advancements in Polymer-Assisted Layer-by-Layer Fabrication of Wearable Sensors for Health Monitoring.

Recent advancements in polymer-assisted layer-by-layer (LbL) fabrication have revolutionized the development of wearable sensors for health monitoring. LbL self-assembly has emerged as a powerful and versatile technique for creating conformal, flexible, and multi-functional films on various substrates, making it particularly suitable for fabricating wearable sensors. The incorporation of polymers, both natural and synthetic, has played a crucial role in enhancing the performance, stability, and biocompatibility of these sensors. This review provides a comprehensive overview of the principles of LbL self-assembly, the role of polymers in sensor fabrication, and the various types of LbL-fabricated wearable sensors for physical, chemical, and biological sensing. The applications of these sensors in continuous health monitoring, disease diagnosis, and management are discussed in detail, highlighting their potential to revolutionize personalized healthcare. Despite significant progress, challenges related to long-term stability, biocompatibility, data acquisition, and large-scale manufacturing are still to be addressed, providing insights into future research directions. With continued advancements in polymer-assisted LbL fabrication and related fields, wearable sensors are poised to improve the quality of life for individuals worldwide.

Effectiveness of the lay health advisor program on oral function and quality of life in aboriginal older adults: A randomized controlled trial.

BACKGROUND: Aboriginal older adults residing in remote areas have poor oral function due to inadequate access to healthcare services. Lay health advisor (LHA) strategies can fill capacity shortages of healthcare professionals in rural communities and increase population acceptance of health care or healthy behaviours. OBJECTIVE(S): To evaluate the effectiveness the LHA program on oral function and oral health-related quality of life (OHRQoL) among older adults in aboriginal community. METHODS: Participants were randomly assigned to an experimental group (EG; n = 122) and a control group (CG; n = 118). All participants performed oral exercises, and the EG received additional one-on-one 30-min lessons by an LHA over 4 weeks. Data were collected through face-to-face interview and oral examination. The generalized estimating equation model was used to analyse changes in outcomes over time. RESULTS: The EG exhibited significantly greater improvement in swallowing (ß = .63) at the 6-month follow-up and in masticatory performance (ß = .52) and pronunciation of the syllable/pa/ (ß = 2.65) at the 2-week follow-up than the CG did. The EG had a significantly lower plaque control record (ß = -.14) and plaque index (ß = -.30) at the 3-month follow-up than the CG did. Moreover, the OHRQoL was significantly increased at 6-months follow-up in the EG (p = .010). CONCLUSION: The LHA program had positive effects on chewing, swallowing and plaque control in aboriginal older adults. LHA group also experienced positive long-term effect on OHRQoL after intervention.

Mechanical Strain Induces and Increases Vesicular Release Monitored by Microfabricated Stretchable Electrodes.

Exocytosis involving the fusion of intracellular vesicles with cell membrane, is thought to be modulated by the mechanical cues in the microenvironment. Single-cell electrochemistry can offer unique information about the quantification and kinetics of exocytotic events; however, the effects of mechanical force on vesicular release have been poorly explored. Herein, we developed a stretchable microelectrode with excellent electrochemical stability under mechanical deformation by microfabrication of functionalized poly(3,4-ethylenedioxythiophene) conductive ink, which achieved real-time quantitation of strain-induced vesicular exocytosis from a single cell for the first time. We found that mechanical strain could cause calcium influx via the activation of Piezo1 channels in chromaffin cell, initiating the vesicular exocytosis process. Interestingly, mechanical strain increases the amount of catecholamines released by accelerating the opening and prolonging the closing of fusion pore during exocytosis. This work is expected to provide revealing insights into the regulatory effects of mechanical stimuli on vesicular exocytosis.

Characterization of dental dust particles and their pathogenicity to respiratory system: a narrative review.

OBJECTIVES: Dental professionals are exposed to large amounts of dust particles during routine treatment and denture processing. This article provides a narrative review to investigate the most prevalent dust-related respiratory diseases among dental professionals and to discuss the effects of dental dust on human respiratory health. MATERIALS AND METHODS: A literature search was performed in PubMed/Medline, Web of Science, and Embase for articles published between 1990 and 2022. Any articles on the occupational respiratory health effects of dental dust were included. RESULTS: The characterization and toxicity evaluation of dental dust show a correlation between dust exposure and respiratory system injury, and the possible pathogenic mechanism of dust is to cause lung injury and abnormal repair processes. The combination use of personal protective equipment and particle removal devices can effectively reduce the adverse health effects of dust exposure. CONCLUSIONS: Dental dust should be considered an additional occupational hazard in dental practice. However, clinical data and scientific evidence on this topic are still scarce. Further research is required to quantify dust in the dental work environment and clarify its pathogenicity and potential toxicological pathways. Nonetheless, the prevention of dust exposure should become a consensus among dental practitioners. CLINICAL RELEVANCE: This review provides dental practitioners with a comprehensive understanding and preventive advice on respiratory health problems associated with dust exposure.

An Overview to Molecularly Imprinted Electrochemical Sensors for the Detection of Bisphenol A.

Bisphenol A (BPA) is an industrial chemical used extensively in plastics and resins. However, its endocrine-disrupting properties pose risks to human health and the environment. Thus, accurate and rapid detection of BPA is crucial for exposure monitoring and risk mitigation. Molecularly imprinted electrochemical sensors (MIES) have emerged as a promising tool for BPA detection due to their high selectivity, sensitivity, affordability, and portability. This review provides a comprehensive overview of recent advances in MIES for BPA detection. We discuss the operating principles, fabrication strategies, materials, and methods used in MIES. Key findings show that MIES demonstrate detection limits comparable or superior to conventional methods like HPLC and GC-MS. Selectivity studies reveal excellent discrimination between BPA and structural analogs. Recent innovations in nanomaterials, novel monomers, and fabrication techniques have enhanced sensitivity, selectivity, and stability. However, limitations exist in reproducibility, selectivity, and stability. While challenges remain, MIES provide a low-cost portable detection method suitable for on-site BPA monitoring in diverse sectors. Further optimization of sensor fabrication and characterization will enable the immense potential of MIES for field-based BPA detection.

Probing Molecular Interactions of Antibody Drugs, Silicone Oil, and Surfactant at Buried Interfaces In Situ.

Antibody drugs have been rapidly developed to cure many diseases including COVID-19 infection. Silicone oil is commonly used as a lubricant coating material for devices used in the pharmaceutical industry to store and administer antibody drug formulations. However, the interaction between silicone oil and antibody molecules could lead to the adsorption, denaturation, and aggregation of antibody molecules, impacting the efficacy of antibody drugs. Here, we studied the molecular interactions between antibodies and silicone oil in situ in real time. The effect of the surfactant on such interactions was also investigated. Specifically, the adsorption dynamics of a bispecific antibody (BsAb) onto a silicone oil surface without and with different concentrations of the surfactant PS80 in antibody solutions were monitored. Also the possible lowest effective PS80 concentrations that can prevent the adsorption of BsAb as well as a monoclonal antibody (mAb) onto silicone oil were measured. It was found that different concentrations of PS80 are required for preventing the adsorption of different antibodies. Both BsAB and mAB denature on silicone oil without a surfactant. However, for a low surfactant concentration in the solution, although the surfactant could not completely prevent the antibody from adsorption, it could maintain the native structures of adsorbed BsAb and mAb antibodies on silicone oil. This is important knowledge, showing that to prevent antibody aggregation on silicone oil it is not necessary to add surfactant to a concentration high enough to completely minimize protein adsorption.

Effects of artificial intelligence-assisted dental monitoring intervention in patients with periodontitis: A randomized controlled trial.

AIM: To evaluate the effects of an at-home artificial intelligence (AI)-assisted dental monitoring application on treatment outcomes in patients with periodontitis. MATERIALS AND METHODS: Participants with periodontitis were recruited and randomly assigned to an AI (n = 16), AI and human counselling (AIHC; n = 17), or control (CG; n = 20) group. All participants received non-surgical periodontal treatment. We employed an AI-assisted tool called DENTAL MONITORING® (DM) intervention, a new technological AI monitoring product that utilizes smartphone cameras for intra-oral scanning and assessment. Patients in the AI and AIHC groups received additional (a) DM or (b) DM, respectively, with real-person counselling over 3 months. Periodontal parameters were collected at baseline and follow-ups. A mixed-design model analysed the follow-up effects over time. RESULTS: The AI and AIHC groups, respectively, exhibited greater improvement in probing pocket depth (PPD) (mean diff = -0.9 ± 0.4 and -1.4 ± 0.3, effect size [ES] = 0.76 and 1.98), clinical attachment level (mean diff = -0.8 ± 0.3 and -1.4 ± 0.3, ES = 0.84 and 1.77), and plaque index (mean diff = -0.5 ± 0.2 and - 0.7 ± 0.2, ES = 0.93 and 1.81) at 3-month follow-up than the CG did. The AIHC group had a greater reduction in PPD (ES = 0.46) and clinical attachment level (ES = 0.64) at the 3-month follow-up compared with the AI group. CONCLUSIONS: Using AI monitoring at home had a positive effect on treatment outcomes for patients with periodontitis. Patients who received AI-assisted health counselling exhibited better treatment outcomes than did patients who received AI monitoring alone.

Immediate Implant Placement in Posterior Sockets With Periapical Infection and Bone Defects: Three Case Reports.

Immediate implant placement is considered a well-accepted procedure due to its advantages and predictable survival rates. However, data on immediate implantation in posterior sockets with infection and bone defects are limited. The purpose of this clinical report was to describe 3 cases of hopeless posterior teeth with periapical infection and relatively large destruction that were successfully treated with immediate implant placement. The mean follow-up time was 22 months. On the basis of correct clinical decision and treatment procedure, immediate implant placement may be a reliable treatment option for compromised posterior sockets.

Environmental distribution, transport and ecotoxicity of microplastics: A review.

Microplastics (MPs) have become a global environmental pollutant because of their unique properties. The extensive MP toxicity reports have focused on the aquatic environment, while the pervasive MP contamination in the soil and air has largely been overlooked. This review summarizes the abundance, sources and transport of MPs in different environments. It analyzes the toxicity of MPs based on various environmentally relevant bacterial, cellular, plant, aquatic animal and mammalian test groups, using both in vitro and in vivo experiments. The combined toxicity effects of MPs and various other environmental pollutants on ecosystems are also discussed. Currently, data on the adverse effects on combined MP toxicity are very limited. Thus, a systematic assessment of the environmental risk in different environments and in various species from MPs is challenging. Thus, this review proposes the possible risks and identifies the knowledge gaps posed by MPs to food safety and human health.

Effects of health-promoting school strategy on dental plaque control and preventive behaviors in schoolchildren in high-caries, rural areas of Taiwan: a quasi-experimental design.

BACKGROUND: We evaluated the effects of health-promoting school (HPS) strategy on plaque control and behavior change in high-caries schoolchildren in Taitung, Taiwan. METHODS: A quasi-experimental design was adopted; six intervention schools (intervention group [IG]) and six comparison schools (comparison group [CG]) were selected from elementary schools with higher-than-average caries rates (> 68%). The IG was selected using cluster sampling, and the CG was selected to match the IG. In total, the IG and CG groups included 166 and 174 children each. The selected schools implemented the HPS framework for 3 months in the 2019 academic year. An oral examination of dental plaque was administered, and a self-administered questionnaire regarding knowledge, attitude, self-efficacy, and behaviors was distributed at baseline and at 2-week follow-up. A linear and logistic regression model using generalized estimating equations (GEEs) was used to analyze the differences between baseline and the follow-up data. RESULTS: Compared with the CG, the IG had a greater reduction in plaque index among second graders (ß = - 0.36) and plaque control record scores among second, fourth, and sixth graders (ß = - 27.48, - 26.04, and - 18.38, respectively). The IG also exhibited a greater increase at follow-up with respect to oral health-related knowledge among second graders and fourth graders (ß = 1.46 and ß = 0.92, respectively), attitude toward oral hygiene behaviors among sixth graders (ß = 1.78), and self-efficacy regarding flossing for sixth graders (ß = 1.43). Sixth graders in the IG were significantly more likely to brush before sleeping (adjusted odds ratio [aOR] = 2.99) and use fluoride toothpaste (aOR = 5.88) than those in the CG. CONCLUSIONS: The HPS strategy was effective in reducing dental plaque and promoting preventing behaviors in rural high-caries schoolchildren.

Identification of a unique 1,4-ß-D-glucan glucohydrolase of glycoside hydrolase family 9 from Cytophaga hutchinsonii.

Cytophaga hutchinsonii is an aerobic cellulolytic soil bacterium that rapidly digests crystalline cellulose. The predicted mechanism by which C. hutchinsonii digests cellulose differs from that of other known cellulolytic bacteria and fungi. The genome of C. hutchinsonii contains 22 glycoside hydrolase (GH) genes, which may be involved in cellulose degradation. One predicted GH with uncertain specificity, CHU_0961, is a modular enzyme with several modules. In this study, phylogenetic tree of the catalytic modules of the GH9 enzymes showed that CHU_0961 and its homologues formed a new group (group C) of GH9 enzymes. The catalytic module of CHU_0961 (CHU_0961B) was identified as a 1,4-ß-D-glucan glucohydrolase (EC 3.2.1.74) that has unique properties compared with known GH9 cellulases. CHU_0961B showed highest activity against barley glucan, but low activity against other polysaccharides. Interestingly, CHU_0961B showed similar activity against ρ-nitrophenyl ß-D-cellobioside (ρ-NPC) and ρ-nitrophenyl ß-D-glucopyranoside. CHU_0961B released glucose from the nonreducing end of cello-oligosaccharides, ρ-NPC, and barley glucan in a nonprocessive exo-type mode. CHU_0961B also showed same hydrolysis mode against deacetyl-chitooligosaccharides as against cello-oligosaccharides. The kcat/Km values for CHU_0961B against cello-oligosaccharides increased as the degree of polymerization increased, and its kcat/Km for cellohexose was 750 times higher than that for cellobiose. Site-directed mutagenesis showed that threonine 321 in CHU_0961 played a role in hydrolyzing cellobiose to glucose. CHU_0961 may act synergistically with other cellulases to convert cellulose to glucose on the bacterial cell surface. The end product, glucose, may initiate cellulose degradation to provide nutrients for bacterial proliferation in the early stage of C. hutchinsonii growth. KEY POINTS: • CHU_0961 and its homologues formed a novel group (group C) of GH9 enzymes. • CHU_0961 was identified as a 1,4-ß-d-glucan glucohydrolase with unique properties. • CHU_0961 may play an important role in the early stage of C. hutchinsonii growth.

Emerging technologies for the pretreatment of lignocellulosic materials for bio-based products.

Exploring a cheap and clean renewable energy has become a common destination round the world with the depletion of oil resources and the concerns of increasing energy demands. Lignocellulosic biomass is the most abundant renewable resource in the biosphere, and the total biomass formed by plant photosynthesis reached more than 200 billion tons every year. Cellulase and hemicellulose and lignin degradation enzymes, the efficient biocatalyst, could efficiently convert the lignocellulosic biomass into sugars that could be further processed into biofuels, biochemical, and biomaterial for human requirement. The utilization and conversion of cellulosic biomass has great significance to solve the problems such as environmental pollution and energy crisis. Lignocellulosic materials are widely considered as important sources to produce sugar streams that can be fermented into ethanol and other organic chemicals. Pretreatment is a necessary step to overcome its intrinsic recalcitrant nature prior to the production of important biomaterial that has been investigated for nearly 200 years. Emerging research has focused in order of economical, eco-friendly, and time-effective solutions, for large-scale operational approach. These new mentioned technologies are promising for lignocellulosic biomass degradation in a huge scale biorefinery. This review article has briefly explained the emerging technologies especially the consolidated bioprocessing, chemistry, and physical base pretreatment and their importance in the valorization of lignocellulosic biomass conversion.

Transcription Factor Atf1 Regulates Expression of Cellulase and Xylanase Genes during Solid-State Fermentation of Ascomycetes.

Transcriptional regulation of cellulolytic and xylolytic genes in ascomycete fungi is controlled by specific carbon sources in different external environments. Here, comparative transcriptomic analyses of Penicillium oxalicum grown on wheat bran (WB), WB plus rice straw (WR), or WB plus Avicel (WA) as the sole carbon source under solid-state fermentation (SSF) revealed that most of the differentially expressed genes (DEGs) were involved in metabolism, specifically, carbohydrate metabolism. Of the DEGs, the basic core carbohydrate-active enzyme-encoding genes which responded to the plant biomass resources were identified in P. oxalicum, and their transcriptional levels changed to various extents depending on the different carbon sources. Moreover, this study found that three deletion mutants of genes encoding putative transcription factors showed significant alterations in filter paper cellulase production compared with that of a parental P. oxalicum strain with a deletion of Ku70 (ΔPoxKu70 strain) when grown on WR under SSF. Importantly, the ΔPoxAtf1 mutant (with a deletion of P. oxalicumAtf1, also called POX03016) displayed 46.1 to 183.2% more cellulase and xylanase production than a ΔPoxKu70 mutant after 2 days of growth on WR. RNA sequencing and quantitative reverse transcription-PCR revealed that PoxAtf1 dynamically regulated the expression of major cellulase and xylanase genes under SSF. PoxAtf1 bound to the promoter regions of the key cellulase and xylanase genes in vitro This study provides novel insights into the regulatory mechanism of fungal cellulase and xylanase gene expression under SSF.IMPORTANCE The transition to a more environmentally friendly economy encourages studies involving the high-value-added utilization of lignocellulosic biomass. Solid-state fermentation (SSF), that simulates the natural habitat of soil microorganisms, is used for a variety of applications such as biomass biorefinery. Prior to the current study, our understanding of genome-wide gene expression and of the regulation of gene expression of lignocellulose-degrading enzymes in ascomycete fungi during SSF was limited. Here, we employed RNA sequencing and genetic analyses to investigate transcriptomes of Penicillium oxalicum strain EU2101 cultured on medium containing different carbon sources and to identify and characterize transcription factors for regulating the expression of cellulase and xylanase genes during SSF. The results generated will provide novel insights into genetic engineering of filamentous fungi to further increase enzyme production.

Probing the Interfacial Interactions of Monoclonal and Bispecific Antibodies at the Silicone Oil-Aqueous Solution Interface by Using Sum Frequency Generation Vibrational Spectroscopy.

Silicone oil has been widely utilized in the pharmaceutical industry especially as a lubricant coating commonly used in syringes for the smooth delivery of drugs. Protein structure perturbation and aggregation have been reported upon protein contacting silicone oil by using indirect methods and ex-situ techniques. The conclusions derived from such indirect and ex-situ methods may not truly reflect the exact nature of the protein-silicone oil interfacial interactions. Recently, we have successfully demonstrated that sum frequency generation (SFG) vibrational spectroscopy can be used as a powerful and direct method of studying the fusion protein-silicone oil interfacial interactions in situ and in real time. In this article, we studied monoclonal and bispecific antibody interactions with the silicone oil surface by using SFG spectroscopy. Being structurally and functionally different in the nature of fusion proteins and antibodies, this study is important in enhancing our current understanding of protein-silicone oil interfacial interactions. Both types of antibodies investigated here readily and strongly adsorb onto the silicone oil surface and remain stable at least for 10 h. SFG spectra in the amide I region for monoclonal and bispecific antibodies centered at 1660 and 1665 cm-1, respectively, suggest the difference in their molecular structures. The absence of the antibody signals in the amide I region of time-dependent and static SFG spectra obtained for preadsorbed antibodies onto silicone oil after contacting polysorbate 80 (PS-80) surfactant suggests that PS-80 can effectively remove both types of antibodies from the silicone oil surface. This study demonstrated the feasibility of using SFG spectroscopy as a powerful tool for probing the antibody-interfacial interactions in situ and in real time.

Selective enrichment of glycopeptides based on copper tetra(N-carbonylacrylic) aminephthalocyanine and iminodiacetic acid functionalized polymer monolith.

Efficient separation and enrichment of low-abundance glycopeptides from complex biological samples is the key to the discovery of disease biomarkers. In this work, a new material was prepared by coating copper tetra(N-carbonylacrylic) aminephthalocyanine and iminodiacetic acid onto poly(glycidyl methacrylate-pentaerythritol triacrylate) monolith. The monolith was applied to polymer monolithic microextraction for specific capture of glycopeptides coupled with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The developed monolith exhibited satisfactory efficiency for glycopeptide enrichment with high selectivity and detection sensitivity. When the tryptic digest of immunoglobulin G was used as the sample, total 24 glycopeptides were identified and the detection limit was determined as 5 fmol. When the approach was applied to the analysis of glycopeptides in the mixture of bovine serum albumin and immunoglobulin G (100:1, m/m) digests, 16 glycopeptides could still be observed. Moreover, the monolith was successfully applied to the selective enrichment of glycopeptides from human serum digests, exhibiting great practicability in identifying low-abundance glycopeptides in complex biological samples.

Implant-Retained Overdenture for a Patient With Severe Lichen Planus: A Case Report With 3 Years' Follow-Up and a Systematic Review.

PURPOSE: The purpose of this study was to describe a new case using implant-retained overdentures in a patient with severe oral lichen planus (OLP) and to perform a literature review to evaluate the effectiveness and safety of implant rehabilitation in OLP patients. MATERIAL AND METHODS: In our patient with erosive OLP, restoration was performed with implant-retained overdentures using the Locator attachment system (Zest Anchors, Escondido, CA). Our case showed favorable restorative results and excellent implant osseointegration with acceptable marginal bone resorption during the follow-up period of 3 years. We performed a literature search of the PubMed (Medline), Embase, and Cochrane databases for articles published between 1990 and 2018 using the key terms "oral lichen planus" and "implant." RESULTS: This search identified 13 publications, including 9 single case reports or case series and 4 small-scale controlled studies. A total of 86 OLP patients and 259 dental implants were analyzed. The survival rate of implants was 95.8% during a follow-up period ranging from 1 to 13 years. CONCLUSION: Dental implants seem to be an acceptable and reliable treatment option in patients with OLP. Nevertheless, clinical information on this topic is still scarce, and more well-designed randomized studies are needed to define the benefits and risks of implant rehabilitation in OLP patients.

Anti-Biofilm Property of Bioactive Upconversion Nanocomposites Containing Chlorin e6 against Periodontal Pathogens.

Photodynamic therapy (PDT) based periodontal disease treatment has received extensive attention. However, the deep tissue location of periodontal plaque makes the conventional PDT encounter a bottleneck. Herein, upconversion fluorescent nanomaterial with near-infrared light excitation was introduced into the treatment of periodontal disease, overcoming the limited tissue penetration depth of visible light in PDT. Photosensitizer Ce6 molecules were combined with upconversion nanoparticles (UCNPs) NaYF4:Yb,Er with a novel strategy. The hydrophobic UCNPs were modified with amphiphilic silane, utilizing the hydrophobic chain of the silane to bind to the hydrophobic groups of the UCNPs through a hydrophobic-hydrophobic interaction, and the Ce6 molecules were loaded in this hydrophobic layer. This achieves both the conversion of the hydrophobic to the hydrophilic surface and the loading of the oily photosensitizer molecules. Because the excitation position of the Ce6 molecule is in the red region, Mn ions were doped to enhance red light, and thus the improved PDT function. This Ce6 loaded UCNPs composites with efficient red upconversion luminescence show remarkable bacteriological therapeutic effect on Porphyromonas gingivalis, Prevotella intermedia and Fusobacterium nucleatum and the corresponding biofilms under 980 nm irradiation, indicating a high application prospect in the treatment of periodontal diseases.

Purification and characterization of an endo-xylanase from Trichoderma sp., with xylobiose as the main product from xylan hydrolysis.

Fungal endo-ß-1,4-xylanases (endo-xylanases) can hydrolyze xylan into xylooligosaccharides (XOS), and have potential biotechnological applications for the exploitation of natural renewable polysaccharides. In the current study, we aimed to screen and characterize an efficient fungal endo-xylanase from 100 natural humus-rich soil samples collected in Guizhou Province, China, using extracted sugarcane bagasse xylan (SBX) as the sole carbon source. Initially, 182 fungal isolates producing xylanases were selected, among which Trichoderma sp. strain TP3-36 was identified as showing the highest xylanase activity of 295 U/mL with xylobiose (X2) as the main product when beechwood xylan was used as substrate. Subsequently, a glycoside hydrolase family 11 endo-xylanase, TXyn11A, was purified from strain TP3-36, and its optimal pH and temperature for activity against beechwood xylan were identified to be 5.0 and 55 °C, respectively. TXyn11A was stable across a broad pH range (3.0-10.0), and exhibited strict substrate specificity, including xylan from beechwood, wheat, rye, and sugarcane bagasse, with Km and Vmax values of 5 mg/mL and 1250 µmol/mg min, respectively, toward beechwood xylan. Intriguingly, the main product obtained from hydrolysis of beechwood xylan by TXyn11A was xylobiose, whereas SBX hydrolysis resulted in both X2 and xylotriose. Overall, these characteristics of the endo-xylanase TXyn11A indicate several potential industrial applications.

Integrity of Membrane Structures in Giant Unilamellar Vesicles as Assay for Antioxidants and Prooxidants.

We have attempted to evaluate, on the basis of optical microscopy for a single giant unilamellar vesicle (GUV), the potency of antioxidants in protecting GUV membranes from oxidative destruction. Photosensitized membrane budding of GUVs prepared from soybean phosphatidylcholine with chlorophyll a (Chl a) and ß-carotene (ß-Car) as photosensitizer and protector, respectively, were followed by microscopic imaging. A dimensionless entropy parameter, ΔE, as derived from the time-resolved microscopic images, was employed to describe the evolution of morphological variation of GUVs. As an indication of membrane instability, the budding process showed three successive temporal regimes as a common feature: a lag phase prior to the initiation of budding characterized by LP (in s), a budding phase when ΔE increased with a rate of kΔE (in s-1), and an ending phase with morphology stabilized at a constant ΔEend (dimensionless). We show that the phase-associated parameters can be objectively obtained by fitting the ΔE-t kinetics curves to a Boltzmann function and that all of the parameters are rather sensitive to ß-Car concentration. As for the efficacy of these parameters in quantifying the protection potency of ß-Car, kΔE is shown to be most sensitive for ß-Car in a concentration regime of biological significance of <1 × 10-7 M, whereas LP and ΔEend are more sensitive for ß-Car concentrations exceeding 1 × 10-7 M. Furthermore, based on the results of GUV imaging and fluorescence and Raman spectroscopies, we have revealed for different phases the mechanistic interplay among 1O2* diffusion, PC-OOH accumulation, Chl a and/or ß-Car consumption, and the morphological variation. The developed assay should be valuable for characterizing the potency of antioxidants or prooxidants in the protection or destruction of the membrane integrity of GUVs.