Natural Organic Matter Enhances Natural Transformation of Extracellular Antibiotic Resistance Genes in Sunlit Water.

Antibiotic resistance genes (ARGs) as emerging environmental contaminants exacerbate the risk of spreading antibiotic resistance. Natural organic matter (NOM) is ubiquitous in aquatic environments and plays a crucial role in biogeochemical cycles. However, its impact on the dissemination of extracellular antibiotic resistance genes (eARGs) under sunlight exposure remains elusive. This study reveals that environmentally relevant levels of NOM (0.1-20 mg/L) can significantly enhance the natural transformation frequency of the model bacterium Acinetobacter baylyi ADP1 by up to 7.6-fold under simulated sunlight. Similarly, this enhancement was consistently observed in natural water and wastewater systems. Further mechanism analysis revealed that reactive oxygen species (ROS) generated by NOM under sunlight irradiation, primarily singlet oxygen and hydroxyl radicals, play a crucial role in this process. These ROS induce intracellular oxidative stress and elevated cellular membrane permeability, thereby indirectly boosting ATP production and enhancing cell competence of extracellular DNA uptake and integration. Our findings highlight a previously underestimated role of natural factors in the dissemination of eARGs within aquatic ecosystems and deepen our understanding of the complex interplay between NOM, sunlight, and microbes in environmental water bodies. This underscores the importance of developing comprehensive strategies to mitigate the spread of antibiotic resistance in aquatic environments.

Identification and replication of urine metabolites associated with short-term and habitual intake of sweet and fatty snacks in European children and adolescents.

BACKGROUND: Intake of sweet and fatty snacks may partly contribute to the occurrence of obesity and other health conditions in childhood. Traditional dietary assessment methods may be limited in accurately assessing the intake of sweet and fatty snacks in children. Metabolite biomarkers may aid the objective assessment of children's food intake and support establishing diet-disease relationships. OBJECTIVE: The present study aimed to identify biomarkers of sweet and fatty snack intake in two independent cohorts of European children. METHODS: We used data from the IDEFICS/I.Family cohort from baseline (2007/2008) and two follow-up examination waves (2009/2010 and 2013/2014). In total, n=1788 urine samples from 599 children were analysed for untargeted metabolomics using high-resolution liquid chromatography-mass spectrometry. Short-term dietary intake was assessed by 24-hour dietary recalls, and habitual dietary intake was calculated with the National Cancer Institute method. Data from the DONALD cohort of 24-hour urine samples (n=567) and 3-day weighted dietary records were used for external replication of results. Multivariate modelling with Unbiased Variable selection in R (MUVR) algorithms and linear mixed models were used to identify novel biomarkers. Metabolite features significantly associated with dietary intake were then annotated. RESULTS: In total, 66 metabolites were discovered and found to be statistically significant for "chocolate candy", "cakes, puddings & cookies", "candy & sweets", "ice cream", and "crisps". Most of the features (n=62) could not be annotated. Short-term and habitual chocolate intake were positively associated with theobromine, xanthosine, and cyclo(L-prolyl-L-valyl). These results were replicated in the DONALD cohort. Short-term "candy & sweets" intake was negatively associated with octenoylcarnitine. CONCLUSION: We identified potential metabolite biomarkers of sweet and fatty snacks in children, of which three biomarkers of chocolate intake, namely theobromine, xanthosine, and cyclo(L-prolyl-L-valyl) were externally replicated. However, these potential biomarkers require further validation in children.

Massive multiplexing of spatially resolved single neuron projections with axonal BARseq.

Neurons in the cortex are heterogeneous, sending diverse axonal projections to multiple brain regions. Unraveling the logic of these projections requires single-neuron resolution. Although a growing number of techniques have enabled high-throughput reconstruction, these techniques are typically limited to dozens or at most hundreds of neurons per brain, requiring that statistical analyses combine data from different specimens. Here we present axonal BARseq, a high-throughput approach based on reading out nucleic acid barcodes using in situ RNA sequencing, which enables analysis of even densely labeled neurons. As a proof of principle, we have mapped the long-range projections of >8000 primary auditory cortex neurons from a single male mouse. We identified major cell types based on projection targets and axonal trajectory. The large sample size enabled us to systematically quantify the projections of intratelencephalic (IT) neurons, and revealed that individual IT neurons project to different layers in an area-dependent fashion. Axonal BARseq is a powerful technique for studying the heterogeneity of single neuronal projections at high throughput within individual brains.

Indole alleviates nonalcoholic fatty liver disease in an ACE2-dependent manner.

Indole is a microbial metabolite produced by the gut microbiota through the degradation of dietary tryptophan, known for its well-established anti-inflammatory and antioxidant properties. In this study, we collected fecal samples from mice fed a high-fat diet (HFD) and those on a standard diet (SD), then conducted 16S rRNA sequencing to analyze their gut microbiota. The analysis revealed distinct differences in the dominant bacterial species between the two groups, with a significant decrease in indole-producing probiotics in the HFD mice compared to the SD group. Then we administered oral indole treatment to male C57BL/6J mice with HFD-induced NAFLD and observed a significant improvement in hepatic steatosis and inflammation. Notably, indole alleviated the HFD-induced decline in serum Angiotensin-(1-7) [Ang-(1-7)] levels and Angiotensin-Converting Enzyme 2 (ACE2) expression. To further investigate the role of indole and ACE2 in NAFLD, we conducted experiments using ACE2 knockout (ACE2KO) mice that were also induced with HFD-induced NAFLD and treated with indole. Interestingly, the protective effects of indole were compromised in the absence of ACE2. In HepG2 cells, indole similarly stimulated ACE2 expression and, in an ACE2-dependent manner, reduced ROS generation, maintained mitochondrial membrane potential stability, and increased SIRT3 expression. In summary, our results highlight the formation of a biologically active gut-liver axis between the gut microbiota and the liver through the tryptophan metabolite indole, which mitigates NAFLD in an ACE2-dependent manner. Elevating dietary tryptophan and increasing indole levels may represent an effective approach for preventing and treating NAFLD.

Analysis of the primary factors influencing donor derived cell-free DNA testing in kidney transplantation.

The donor-derived cell-free DNA (ddcfDNA) is found in the plasma and urine of kidney transplant recipients and displays notable potential in diagnosing rejection, specifically antibody-mediated rejection (ABMR). Nonetheless, the quantitative methods of ddcfDNA lacking standardization and diverse detection techniques can impact the test outcomes. Besides, both the fraction and absolute values of ddcfDNA have been reported as valuable markers for rejection diagnosis, but they carry distinct meanings and are special in various pathological conditions. Additionally, ddcfDNA is highly sensitive to kidney transplant injury. The various sampling times and combination with other diseases can indeed impact ddcfDNA detection values. This review comprehensively analyses the various factors affecting ddcfDNA detection in kidney transplantation, including the number of SNPs and sequencing depths. Furthermore, different pathological conditions, distinct sampling time points, and the presence of complex heterologous signals can influence ddcfDNA testing results in kidney transplantation. The review also provides insights into ddcfDNA testing on different platforms along with key considerations.

New progress in HBV control and the cascade of health care for people living with HBV in China: evidence from the fourth national serological survey, 2020.

Background: Since 1992, when recombinant hepatitis B vaccine was introduced in China, government health officials have used nationally representative serological surveys to monitor progress in prevention and control of hepatitis B. In 2020, we conducted the fourth seroepidemiological survey, which for the first time included medical evaluation of the clinical status of HBsAg positive subjects over the age of 15 and their medical management. We report survey results in comparison with the three previous surveys. Methods: Consistent with previous national surveys, the 2020 survey used a stratified, three-stage cluster random sampling method to select for evaluation 1-69-year-olds in 120 national disease surveillance points. Blood samples were tested for HBsAg, anti-HBV surface antigen (anti-HBs), and anti-HBV core antigen (anti-HBc) in the National Hepatitis Laboratory of the Institute for Viral Disease Control and Prevention of China CDC. HBsAg positive subjects aged ≥15-year were evaluated for evidence of liver disease, and through face-to-face questionnaire-based survey, we determined the healthcare management cascade of HBV-infected individuals. Findings: HBsAg prevalence in 1-69-year-olds was 5.86%; in children 1-4 years of age, seroprevalence was 0.30%; 75 million people were living with HBV nationwide. Among HBsAg-positive individuals 15 years and older, expert medical examination found that 78.03% were HBsAg carriers with no evidence of liver damage, 19.63% had chronic HBV with liver enzyme abnormalities, 0.84% had evidence of cirrhosis, and 0.15% had evidence of liver cancer. 59.78% of HBsAg + individuals were aware that they were positive before the survey, 30 million were unaware; 38.25% of those who knew they were positive (17 million) had medical indications for antiviral treatment, and 17.33% of these individuals (3 million) were being treated with antivirals. Interpretation: The decline in HBsAg prevalence in the general population, from 9.72% in 1992 to 5.86% in 2020, and in 1-4-year-olds from 9.67% in 1992 to 0.30% in 2020, shows progress that continues on track toward WHO targets for prevention of new infections. Implementation of acceptable strategies to identify infected individuals and offer long-term medical monitoring and management will be important to prevent complications from hepatitis B infection and for meeting WHO cascade-of-care targets. Funding: The study was funded by the Major Science and Technology Special Project of China's 13th 5-Year Plan (grant no. 2017ZX10105015); Central finance-operation of public health emergency response mechanism of Chinese Center for Disease Control and Prevention (131031001000200001, 102393220020010000017).

Functional and Mechanistic Dissection of Protein Glutaminase PG3 and Its Rational Engineering for Enhanced Modification of Myofibrillar Proteins.

Protein glutaminases (PG; EC = 3.5.1.44) are enzymes known for enhancing protein functionality. In this study, we cloned and expressed the gene chryb3 encoding protein glutaminase PG3, exhibiting 39.4 U/mg specific activity. Mature-PG3 featured a substrate channel surrounded by aromatic and hydrophobic amino acids at positions 38-45 and 78-84, with Val81 playing a pivotal role in substrate affinity. The dynamic opening and closing motions between Gly65, Thr66, and Cys164 at the catalytic cleft greatly influence substrate binding and product release. Redesigning catalytic pocket and cocatalytic region produced combinatorial mutant MT6 showing a 2.69-fold increase in specific activity and a 2.99-fold increase at t65 °C1/2. Furthermore, MT6 boosted fish myofibrillar protein (MP) solubility without NaCl. Key residues such as Thr3, Asn54, Val81, Tyr82, Asn107, and Ser108 were vital for PG3-myosin interaction, particularly Asn54 and Asn107. This study sheds light on the catalytic mechanism of PG3 and guided its rational engineering and utilization in low-salt fish MP product production.

Biological and genomic characterization of a polyvalent phage PSH-1 against multidrug-resistant Salmonella Enteritidis.

BACKGROUND: Bacteriophage has been renewed attention as a new antibacterial agent due to the limitations of antibiotic treatment. Bacteriophages are generally thought to be highly host specific and even strain specific, but a small number of polyvalent bacteriophages have been found to infect bacteria of different genera. RESULTS: In this study, a virulent lytic bacteriophage (named Salmonella phage PSH-1) of Salmonella Enteritidis was isolated from the sewage samples of a large-scale pig farm, PSH-1 demonstrated lytic activity against four multidrug-resistant Salmonella Enteritidis isolates and Escherichia coli, and then its biological characteristics, genome and bacteriostatic ability were investigated. The results showed that the initial titer of PSH-1 was 1.15 × 1010 PFU/mL and the optimal multiplicity of infection (MOI) was 0.01, PSH-1 has stable activity in the range of pH 3.0-11.0. One-step growth curve showed that its latent period was 20 min, burst time was 80 min, and the burst was 495 particles. The whole-genome sequencing results revealed phage PSH-1 had a linear dsDNA with 48,466 bp length. The G/C content was 45.33%. Non-coding RNA genes and virulence factors were not found. Eighty- five open reading frames (ORFs) were identified after online annotation. By tests, the use of phage could succeed in controlling the artificial Salmonella contamination in milk at a range of temperatures. CONCLUSIONS: This study reports a novel Salmonella Enteritidis phage PSH-1, which has a robust lytic ability, no virulence factors, and good stability. The characterization and genomic analysis of PSH-1 will develop our understanding of phage biology and diversity and provide a potential arsenal for controlling of salmonellosis.

Efficient circularly polarized multiple resonance thermally activated delayed fluorescence from B,N-embedded hetero[8]helicene enantiomers.

Helicene-based circularly polarized multiple resonance thermally activated delayed fluorescence (CP-MR-TADF) materials are promising for ultra-high-definition and 3D displays, but most of them encounter potential problems such as easy racemization during the thermal deposition process, low luminous efficiency, and low luminescence dissymmetry factor (g lum), making the development of efficient circularly polarized organic light-emitting diodes (CP-OLEDs) a significant challenge. Here, we report a pair of CP-MR-TADF enantiomers with high-order B,N-embedded hetero[8]helicene, (P/M)-BN-TP-ICz, by fusing two MR chromophores, DtCzB and indolo[3,2,1-jk]carbazole (ICz). BN-TP-ICz exhibits green emission in toluene with a peak of 531 nm and a full-width at half-maximum (FWHM) of 36 nm. The optimized CP-OLEDs with enantiomers (P/M)-BN-TP-ICz exhibit green emission with peaks of 540 nm, FWHMs of 38 nm and Commission Internationale de L'Eclairage coordinates of (0.33, 0.65). Moreover, they showcase maximum external quantum efficiencies (EQEs) of 32.0%, with g ELs of +6.49 × 10-4 and -7.74 × 10-4 for devices based on (P)-BN-TP-ICz- and (M)-BN-TP-ICz, respectively.

The Effect of Opioid-Free Anesthesia with Transversus Abdominis Plane Block on Patients Undergoing Laparoscopic Sleeve Gastrectomy: Randomized Controlled Study.

Purpose: Anesthesia for metabolic-bariatric surgery is challenging due to the increased risk of opioid-related adverse events. The purpose of the investigation was to assess the feasibility and efficacy of multimodal opioid-free general anesthesia with transversus abdominis plane (TAP) block for laparoscopic sleeve gastrectomy in contrast with conventional opioid-based general anesthesia. Patients and Methods: Eighty patients who underwent laparoscopic sleeve gastrectomy and eventually 71 patients included in the analysis. They were randomly divided into an opioid-based anesthesia group (control group) with sufentanil or opioid-free anesthesia (OFA) group. Esketamine, dexmedetomidine, and TAP were as part of the OFA. Sevoflurane, dexamethasone, and muscle relaxants were administered intraoperatively to all patients. The primary outcome was antiemetic rescue within 24 hours after surgery. The secondary outcomes included pain scores, analgesic needs, extubation time, complications, the hemodynamic changes, and duration of hospital stay. Results: In contrast with the control group, the need for antiemetic rescue was significantly reduced (p= 0.035). Furthermore, the visual Analog Scale (VAS) for postoperative pain was considerably lower in the OFA group (p <0.01) than it was in the control group. There was no significant difference in the need for analgesic rescue in both groups (p= 0.155). Extubation time and post-anesthesia care unit (PACU) stay duration were equal between the two groups (p =0.328 and p =0.54). At the end of the surgery and after extubation, hemodynamic changes was more pronounced in the OFA group (p =0.027) than the control group. The length of the hospital stay was significantly shorter compared with the control group (p =0.002). Conclusion: OFA with TAP results in a significant decrease in the need for antiemetic rescue, a lower level of pain after the surgery, and a shorter hospital stay in contrast with anesthesia based on opioids.

High internal phase emulsions stabilized by fluorescent phycocyanin for improved stability and bioaccessibility of ß-carotene.

BACKGROUND: High internal phase emulsions (HIPE) are distinguished from ordinary emulsions by higher oil-phase percentage and better storage stability. Recently, HIPE stabilized with protein-based particles has received more attention. However, organic precipitation, chemical cross-linking and thermal denaturation are often needed to stabilize emulsions with natural proteins, and there is an urgent need to reduce the pollution of organic reagents. RESULTS: HIPE loaded with ß-carotene stabilized by phycocyanin was prepared under mild conditions. It demonstrated strong stability in terms of temperature and storage, as evidenced by its 94.17% retention rate and 81.06% bioavailability. This stability was ascribed to the efficient defense against heat and UV rays, which was probably associated with the oil-droplet environment and interfacial protection of phycocyanin. It is speculated that the possible main interaction site between phycocyanin and sorbitol exists near amino acids 110 to 120 of the B chain. The hydrogen bond and hydrophobic interaction between them make the phycocyanin fully adsorbed on the oil-water interface when sorbitol is stable, forming a strong oil-water structure, which increases the stability of the emulsion. CONCLUSION: The outstanding fluorescence characteristics provide a feasible alternative for fluorescent emulsions to distribute and trace active compounds in vitro. HIPE loaded with ß-carotene might have potential as a 3D printing material for edible functional foods. © 2024 Society of Chemical Industry.

Superoxide radical derived metal-free spiro-OMeTAD for highly stable perovskite solar cells.

Lithium salt-doped spiro-OMeTAD is widely used as a hole-transport layer (HTL) for high-efficiency n-i-p perovskite solar cells (PSCs), but unfortunately facing awkward instability for commercialization arising from the intrinsic Li+ migration and hygroscopicity. We herein demonstrate a superoxide radicals (•O2-) derived HTL of metal-free spiro-OMeTAD with remarkable capability of avoiding the conventional tedious oxidation treatment in air for highly stable PSCs. Present work explores the employing of variant-valence Eu(TFSI)2 salts that could generate •O2- for facile and adequate pre-oxidation of spiro-OMeTAD, resulting in the HTL with dramatically increased conductivity and work function. Comparing to devices adopting HTL with LiTFSI doping, the •O2--derived spiro-OMeTAD increases the PSCs efficiency up to 25.45% and 20.76% for 0.05 cm2 active area and 6 × 6 cm2 module, respectively. State-of-art PSCs employing such metal-free HTLs are also demonstrated to show much-improved environmental stability even under harsh conditions, e.g., maintaining over 90% of their initial efficiency after 1000 h of operation at the maximum power point and after 80 light-thermal cycles under simulated low earth orbit conditions, respectively, indicating the potentials of developing metal-free spiro-OMeTAD for low-cost and shortened processing of perovskite photovoltaics.

The Role of Contrast-enhanced Ultrasound in the Femoral Head Perfusion Evaluation: A Pilot Study.

OBJECTIVES: We explored the value of contrast-enhanced ultrasound (CEUS) in evaluating femoral head (FH) perfusion, guiding interventions and follow-up for infants with developmental dysplasia of the hip (DDH) and septic arthritis of the hip (SAH). The aim was to provide robust evidence for clinical assessment. METHODS: Ten infants, including 7 with DDH and 3 with SAH, were prospectively enrolled, with their bilateral hips alternately scanned during the CEUS exams. Twenty hips were classified into the case group (n = 11) and the control group (n = 9). Pre- and post-interventional studies were performed in DDH infants requiring interventions. FH perfusion was assessed by the perfusion area ratio (PAR) and quadrant location of microbubble-defect regions. RESULTS: In the case group, 25 CEUS studies were conducted, including 11 baseline, 7 follow-up and 7 post-intervention studies. The PAR significantly decreased in the case group (49.79% vs. 100.00%, p < 0.05). The microbubble-defect regions averagely affected 2 quadrants, primarily quadrat No. 3 (30%) and No. 4 (32%). Seven hip abduction angle adjustments were made based on pre-interventional studies, resulting in a significant increase in PAR in post-interventional studies (37.63% vs. 60.24%, p < 0.05). PAR increased in follow-up studies compared to baseline values (45.61% vs. 76.07%, p < 0.05). The inter- and intra-observer reproducibility of PAR measurements were excellent (intraclass correlation coefficient, both 0.97). CONCLUSION: CEUS proves to be a promising technique for quantitatively detecting FH perfusion in DDH and SAH infants with high reproducibility. It is valuable for baseline, intra-intervention and follow-up studies, aiming in clinical conditions and therapeutic effect evaluation.

Multilevel factors associated with HIV-related stigma among women living with HIV in Guangdong Province, China: a social-ecological model-informed study.

BACKGROUND: HIV-related stigma continues to hinder optimal HIV care, and its determinants should be understood at multiple levels. Based on the social-ecological model, this study aimed to explore factors associated with HIV-related stigma among women living with HIV in Guangdong Province, China. METHODS: A cross-sectional study was conducted from July to August 2022 to recruit newly reported women living with HIV with a history of pregnancy or current pregnancy in 2021 in 21 cities in Guangdong Province. HIV-related stigma was assessed using an abbreviated Chinese version of Berger's HIV Stigma Scale. Univariate and multivariable hierarchical regression analyses based on the social-ecological model were conducted to explore factors associated with HIV-related stigma and its four dimensions (personalized stigma, disclosure concerns, negative self-image and concerns about public attitudes) at the community/hospital, interpersonal, and individual levels. RESULTS: A moderate level of HIV-related stigma was found among the 360 participants included, with a mean score of 45.26. Multivariable hierarchical regression analysis showed that at the community/hospital-level, individuals were more likely to experience high levels of HIV-related stigma if they had experienced the discriminatory behaviors from health care workers (aOR = 2.34, 95%CI: 1.48-3.70) and if they rated serostatus disclosure services as less helpful (aOR = 0.69, 95%CI: 0.48-0.98). At the interpersonal-level, individuals with an HIV-positive partner (aOR = 1.71, 95%CI: 1.01-2.90) were more likely to experience high levels of HIV-related stigma than those with an HIV-negative or unknown partner. Individuals with high resilience (aOR = 0.22, 95%CI: 0.13-0.35) had lower levels of HIV-related stigma at the individual-level. In addition, ever experiencing discriminatory behaviors from health care workers, thinking serostatus disclosure services helpful, having ever seen publicity about personal interest protection services and complaint channels for people living with HIV(PLHIV), knowing about care and support services for PLHIV from social organizations at the community/hospital-level, partner notification and support at the interpersonal-level, and violations of personal interests, resilience at the individual-level were also associated with different dimensions of HIV-related stigma. CONCLUSIONS: HIV-related stigma was moderate among women living with HIV. The social-ecological model can facilitate a better understanding of factors associated with HIV-related stigma. Multilevel intervention strategies need to be tailored to reduce HIV-related stigma.

Reducing catheter-related bloodstream infections using Lean Six Sigma methodology.

BACKGROUND: Central venous catheters (CVC) are used for dialysis in end-stage renal disease patients, presenting a significant risk for Catheter-Related Bloodstream Infections (CRBSI). While Lean Six Sigma has been effective in reducing CRBSI, its efficacy outside intensive care units (ICU) remains less explored. This study aims to evaluate the effectiveness of Lean Six Sigma in mitigating CRBSI risks among non-ICU hemodialysis patients. METHODS: The study was conducted in a nephrology department, focusing on patients undergoing hemodialysis with temporary CVC from February to December 2021. The Lean Six Sigma method, using Define-Measure-Analyze-Improve-Control (DMAIC) methodology, was implemented in 2022 to reduce CRBSI incidence. The 2021 CRBSI rate served as the benchmark, with a goal to reduce it by the end of 2022. Value-stream mapping, Fishbone Diagrams, and Root Cause Analysis identified potential CRBSI causes. After implementing targeted improvements, CRBSI rates before and after the intervention were compared. RESULTS: The Lean Six Sigma method significantly decreased CRBSI incidence from 12.79 to 2.32 per 1,000 catheter-days following the implementation of targeted interventions ([Formula: see text]=4.60, P = 0.05). This improvement was observed comparing February-December 2021 with January-December 2022. CONCLUSION: The findings demonstrate the effectiveness of the Lean Six Sigma method in non-ICU settings, suggesting broader applicability in hemodialysis patient care.

Digital Dental Biometrics for Human Identification Based on Automated 3D Point Cloud Feature Extraction and Registration.

BACKGROUND: Intraoral scans (IOS) provide precise 3D data of dental crowns and gingival structures. This paper explores an application of IOS in human identification. METHODS: We propose a dental biometrics framework for human identification using 3D dental point clouds based on machine learning-related algorithms, encompassing three stages: data preprocessing, feature extraction, and registration-based identification. In the data preprocessing stage, we use the curvature principle to extract distinguishable tooth crown contours from the original point clouds as the holistic feature identification samples. Based on these samples, we construct four types of local feature identification samples to evaluate identification performance with severe teeth loss. In the feature extraction stage, we conduct voxel downsampling, then extract the geometric and structural features of the point cloud. In the registration-based identification stage, we construct a coarse-to-fine registration scheme in order to realize the identification task. RESULTS: Experimental results on a dataset of 160 individuals demonstrate that our method achieves a Rank-1 recognition rate of 100% using complete tooth crown contours samples. Utilizing the remaining four types of local feature samples yields a Rank-1 recognition rate exceeding 96.05%. CONCLUSIONS: The proposed framework proves effective for human identification, maintaining high identification performance even in extreme cases of partial tooth loss.

Engineering of protein glutaminase for highly efficient modification of fish myofibrillar protein through structure-based and computational-aided strategy.

Protein glutaminase (PG; EC 3.5.1.44) is a class of food-grade enzyme with the potential to significantly improve protein functionality. However, its low catalytic activity and stability greatly hindered industrial application. In this study, we employed structural-based engineering and computational-aided design strategies to target the engineering of protein glutaminase PG5, which led to the development of a combinatorial mutant, MT8, exhibiting a specific activity of 31.1 U/mg and a half-life of 216.2 min at 55 °C. The results indicated that the flexible region in MT8 shifted from the C-terminus to the N-terminus, with increased N-terminal flexibility positively correlating with its catalytic activity. Additionally, MT8 notably boosted fish myofibrillar proteins (MPs) solubility under the absence of NaCl conditions and enhanced their foaming and emulsifying properties. Key residues like Asp31, Ser72, Asn121, Asp471, and Glu485 were crucial for maintaining PG5-myosin interaction, with Ser72 and Asn121 making significant energy contributions.

Multi-omics insights into anti-colitis benefits of the synbiotic and postbiotic derived from wheat bran arabinoxylan and Limosilactobacillus reuteri.

Exploring nutritional therapies that manipulate tryptophan metabolism to activate AhR signaling represents a promising approach for mitigating chronic colitis. Arabinoxylan is a bioactive constituent abundant in wheat bran. Here, we comprehensively investigated anti-colitis potentials of wheat bran arabinoxylan (WBAX), its synbiotic and postbiotic derived from WBAX and Limosilactobacillus reuteri WX-94 (i.e., a probiotic strain exhibiting tryptophan metabolic activity). WBAX fueled L. reuteri and promoted microbial conversion of tryptophan to AhR ligands during in vitro fermentation in the culture medium and in the fecal microbiota from type 2 diabetes. The WBAX postbiotic outperformed WBAX and its synbiotic in augmenting efficacy of tryptophan in restoring DSS-disturbed serum immune markers, colonic tight junction proteins and gene profiles involved in amino acid metabolism and FoxO signaling. The WBAX postbiotic remodeled gut microbiota and superiorly enhanced AhR ligands (i.e., indole metabolites and bile acids), alongside with elevation in colonic AhR and IL-22. Associations between genera and metabolites modified by the postbiotic and colitis in human were verified and strong binding capacities between metabolites and colitis-related targets were demonstrated by molecular docking. Our study advances the novel perspective of WBAX in manipulating tryptophan metabolism and anti-colitis potentials of WBAX postbiotic via promoting gut microbiota-dependent AhR signaling.

Facile synthesis of a new chiral polyimine macrocycle and its application for enantioseparation in high-performance liquid chromatography.

Macrocyclic compounds such as crown ethers and cyclodextrins play an important role in the field of chromatography and show excellent separation performance. The design of simple and convenient methods for the efficient synthesis of novel chiral macrocycles for chromatographic separation is of great significance. In this work, a novel chiral polyimine macrocycle (PIMC) was designed and synthesized by the simply one-step reaction of 2,6-diformyl-4-tert-butylphenol with (S)-(-)-1,2-propanediamine. Then, it was bonded onto silica by the thiol-ene click reaction to construct a new chiral stationary phase (CSP) for high-performance liquid chromatography (HPLC). The chiral separation performance of the proposed CSP was examined by separating various racemates in the normal-phase (NP) and reversed-phase (RP) HPLC. In total, twelve and nine racemates, including ethers, esters, amines, alcohols, organic acids, ketones, and epoxides, were separated to varying degrees via NP-HPLC and RP-HPLC, respectively, Moreover, the CSP offered good chiral separation complementarity to Chiralcel OD-H and Chiralpak AD-H columns for resolution of these test racemates, and it can separate several racemic compounds that either cannot be separated or cannot be separated well be separated by the two commercially available columns. After the column was used for hundreds of injections, the relative standard deviations of the retention time and resolution were below 0.56 % and 0.45 %, respectively, showing the good reproducibility and stability of the CSP. This study provides a simple and convenient approach to synthesize a novel chiral macrocycle and CSP and also indicates the broad application prospects of such chiral PIMCs in HPLC chiral separation.