Radical Three-Component Nitro Spiro-Cyclization of Unsaturated Sulfonamides/Amides to Access NO2-Featured 4-Azaspiro[4.5]decanes.

Free radical three-component nitration/spirocyclization of unsaturated sulfonamides/amides with tert-butyl nitrite was developed for the construction of diverse NO2-revised 4-azaspiro[4.5]decanes. This tandem system featured metal-free participation, simple operation, good selectivity/yields, and a green/low-cost O source. Meanwhile, one nitro-containing complex molecule and a scaled-up operation were performed well to test the synthetic potential of the cascade reaction. Isotopic labeling, radical inhibition experiments, and DFT analysis were carried out to gain insight into the reaction process.

Corrigendum to "Optimization of a tannase-assisted process for obtaining teas rich in theaflavins from Camellia sinensis leaves" [Food Chemistry: X 13 (2022) 100203].

[This corrects the article DOI: 10.1016/j.fochx.2022.100203.].

Repeat Surgery after Percutaneous Endoscopic Lumbar Discectomy for Adolescent Lumbar Disc Herniation: A Multicenter Observational Study.

OBJECTIVE: The reported date in the repeat surgical intervention for adolescent lumbar disc herniation (ALDH) after percutaneous endoscopic lumbar discectomy (PELD) was quite scarce. This study aims to introduce cases of repeat surgeries after PELD for ALDH and assess the incidence, chief causes, repeat surgery methods, and surgical outcomes of repeat surgeries after PELD for ALDH. METHODS: A retrospective multicenter observational study was conducted on patients undergoing repeat surgeries after PELD for ALDH at four tertiary referral hospitals from January 2014 through August 2022. The incidence of repeat surgeries, chief causes, strategies for repeat surgeries, and timing of repeat surgeries were recorded and analyzed. The clinical outcomes were evaluated by the Numeric Rating Scales (NRS) scores and the modified MacNab criteria. Statistical analyses were performed with the Wilcoxon signed-rank test. RESULTS: A total of 23 patients who underwent repeat surgeries after PELD for ALDH were included. The chief causes were re-herniation (homo-lateral re-herniation at the same level, new disc herniation of adjacent level). The repeat surgery methods were revision PELD, micro-endoscopic discectomy (MED), open discectomy and instrumented lumbar inter-body fusion. The NRS scores decreased significantly in follow-up evaluations and these scores demonstrated significant improvement at the last follow-up (p < 0.002). For the modified MacNab criteria, at the last follow-up, 18 patients (78.26%) had an excellent outcome, and the overall success rate was 86.95%. CONCLUSION: This study's data suggest that young patients who underwent repeat surgery improved significantly compared to baseline. The chief cause was re-herniation. Revision PELD was the main surgical procedure, which provides satisfactory clinical results in young patients who underwent repeat surgeries.

Analysis of the thickness characteristics of the left atrial posterior wall and its correlation with the low and no voltage areas of the left atrial posterior wall in patients with atrial fibrillation.

OBJECTIVE: To analyze the relationship between the thickness of the left atrial posterior wall and the low and no voltage zones in the left atrial posterior wall in patients with atrial fibrillation (AF). METHODS: 61 patients admitted to our cardiology department for AF and radiofrequency ablation of AF from January 1, 2020 to May 30, 2022 were enrolled according to inclusion and exclusion criteria. The atrial wall thickness was measured by CT scan. Baseline data, preoperative cardiac ultrasound data, preoperative biochemical parameters, low voltage zone (fibrotic zone) and no voltage zone (scar zone) in the left atrial posterior wall area, and various parameters of posterior left atrial wall thickness were collected. RESULTS: The differences of the thickness between the upper, middle and lower mean levels of the left atrial posterior wall were statistically significant (P = 0.004). The results showed that body mass index was weakly positively correlated with the mean level of total left atrial posterior wall thickness (r = 0.426, P = 0.001) and was statistically significant. The remaining indices were positively or negatively correlated with the mean level of total left atrial posterior wall thickness, but none were statistically significant (P > 0.05). CONCLUSIONS: Both left atrial posterior wall low-voltage zone and voltage-free zone were positively correlated with the mean total left atrial posterior wall thickness, and left atrial posterior wall low-voltage zone and voltage-free zone were significantly positively correlated. Body mass index was weakly positively correlated with total left atrial posterior wall thickness.

Treatment of Adhesive Intestinal Obstruction by Nasogastric Tube Under EnhancedRecovery After Surgery: An Efficacy Analysis.

Objective: To explore the application value of enhanced recovery after surgery (ERAS) in the treatment of adhesive intestinal obstruction (AIO) by nasogastric tube (NGT). Methods: Between December 2020 and December 2022, AIO patients who received NGT treatment at The Fourth Hospital of Changsha were selected, including 43 cases receiving ERAS nursing (observation group) and 35 cases receiving routine care (control group). The two groups were compared in terms of postoperative rehabilitation, as well as their psychology, pain, and quality of life which were evaluated using Self-Rating Anxiety/Depression Scale (SAS/SDS), Visual Analogue Scale (VAS), and Short-Form 36 Item Health Survey (SF-36), respectively. During treatment, the adverse reactions were recorded. Results: In the observation group, the abdominal pain and distension relief time, time to first post-treatment flatus and defecation, abdominal circumference reduction 48 hours after admission, bowel sound recovery, first oral food intake, and extubation time were shorter than those of the control group (P < .05), and the SAS and SDS scores were also lower than those of the control group after treatment (P < .05). At 6-24 hours after treatment, the VAS of the observation group was lower than that of the control group, while the SF-36 score was higher (P < .05). Finally, a lower adverse reaction rate was determined in the observation group compared to the control group (P < .05). Conclusions: ERAS care promotes the recovery of AIO patients after NGT treatment, improves their pain and negative emotions, improves their quality of life, and is extremely valuable for clinical application.

Use of ultrasound to increase the catalytic activity of α-L-rhamnosidase.

α-L-rhamnosidase (Rha) is ubiquitous in nature and has high feasibility in the food and biotechnology industries. A green and environmentally friendly method was used to improve the activity of Rha. Here, we show that the effects of ultrasound treatment on the Rha. Ultrasonic treatment at 80 W for 10 min yielded the highest enzyme activity. Treatment increased enzyme activity by 26.3% and half-life by 124 min. Further, treatment increased the catalytic efficiency of Rha and increased the substrate conversion rate by 33.88%. These results demonstrate that ultrasound increases the catalytic activity and stability of Rha. Thus, ultrasonic treatment of Rha is cost-effective on the industrial scale.

Evaluation of the control efficacy of antagonistic bacteria from V-Ti magnetite mine tailings on kiwifruit brown spots in pot and field experiments.

Seemingly barren heavy-metal-polluted vanadium (V) and titanium (Ti) magnetite mine tailings contain various functional microbes, yet it is unclear whether this includes microbial resources relevant to the biological control of plant diseases. Kiwifruit brown leaf spot disease, caused by Corynespora cassiicola, can seriously reduce kiwifruit yield. To discover effective control measures for kiwifruit leaf spot, 18 bacteria strains among 136 tailing-isolated bacteria from V-Ti magnetite mine tailings were identified as inhibiting C. cassiicola by the confrontation plate method, indicating that antagonistic bacteria surviving in the V-Ti magnetite mine tailings were present at a low level. The 18 antagonistic strains could be divided into two BOX-A1R clusters. The 13 representative strains that were selected for phylogenetic tree construction based on their 16S rRNA sequences belonged to the Bacillus genus. Five predominant strains exhibited different toxin-production times and intensities, with four of them initiating toxin production at 32 h. Among them, Bacillus sp. KT-10 displayed the highest bacteriostatic rate (100%), with a 37.5% growth inhibition rate and an antagonistic band of 3.2 cm against C. cassiicola. Bacillus sp. KT10 also showed a significant inhibitory effect against the expansion speed of kiwifruit brown spots in the pot. The relative control effect was 78.48 and 83.89% at 7 days after the first and last spraying of KT-10 dilution, respectively, confirming a good effect of KT-10 on kiwifruit brown leaf spots in the field. This study demonstrated for the first time that there are some antagonistic bacteria to pathogenic C. cassiicola in V-Ti magnetite mine tailings, and Bacillus sp. KT10 was found to have a good control effect on kiwifruit brown leaf spots in pots and fields, which provided an effective biological control measurement for kiwifruit brown leaf spots.

Grain yield and interspecific competition in an oat-common vetch intercropping system at varying sowing density.

Introduction: Oat (Avena nuda L.) and common vetch (Vicia sativa L.) intercropping in the northern regions of China has resulted in substantial production capabilities. However, there is currently a dearth of comprehensive research on whether this intercropping system can enhance productivity through increased sowing densities and underlying interspecies interaction mechanisms. Methods: A two-year field experiment was conducted in 2022 and 2023 to investigate the yield, biological efficiency, economic efficiency, and competition indicators of oats and common vetch in a high-density intercropping system. Two cropping patterns (monocropping and intercropping) and five sowing densities (D1: 4.5×106 plants ha-1; D2:5.4×106 plants ha-1; D3:6.3×106 plants ha-1; D4: 7.2×106 plants ha-1; and D5: 8.1×106 plants ha-1) were arranged in a randomized block design. Results: At the same sowing density, the intercropped oats exhibited greater grain yield than the monocultures. Increasing the oat sowing density significantly enhanced oat yield, with the D3 level in intercropping showing the highest yield increase, ranging from 30.98% to 31.85%, compared with the monoculture. The common vetch intercropping grain yield was maximized in the D2 treatment. The land equivalent ratio was maximized at the D2 level in both years and was significantly higher than D1, with the land equivalent coefficient, system productivity index, and percentage yield difference suggesting that increasing oat sowing densities improved the productivity of the intercropping system, with the best performance observed at the D2 level. For both years, the proportionate actual yield loss of oat was the highest at the D3 level; significantly surpassing D1, proportionate actual yield loss of common vetch and actual yield loss were the highest at level D2, both significantly surpassing D1. These indicates that appropriate densification contributes to the realization of the advantages of intercropping. With an increased oat sowing density, the economic benefits of the intercropping system were maximized at the D2 and D3 levels. Regarding intercropping competition, oat was the dominant crop under different sowing densities (Aggressivity for oat (AO)>0, relative crowding coefficient for oat (KO)>1, competition ratio for oat (CRO)>1), whereas common vetch was the inferior crop. Compared with the D1 level, the D2 level harmonized the aggressivity, competitive ratio, and relative crowding coefficients of oat and common vetch, significantly increasing crowding coefficient for common vetch (KV) and competition ratio for common vetch by 19.76% to 21.94% and 4.80% to 7.51%, respectively, while reducing KO and CRO. Discussion: This result suggests that in the intercropping of common vetch and oat in alpine regions, rational densification can harmonize interspecific competition and thus improve the biological efficiency and economic benefits of intercropping systems.

Altitude effect on Propofol Pharmacokinetics in Rats.

BACKGROUND: Propofol is an intravenous agent for clinical anesthesia. As the influence of the hypobaric- hypoxic environment (Qinghai-Tibetan region, altitude: 2800-4300 m, PaO2: 15.1-12.4 kPa) on the metabolism of Propofol is complex, the research results on the metabolic characteristics of Propofol in high-altitude areas remain unclear. This study aimed to investigate the pharmacokinetic characteristics of Propofol in a high-altitude hypoxic environment using animal experiments. METHODS: Rats were randomly divided into three groups: high-altitude, medium-altitude, and plain groups. The time of disappearance and recovery of the rat righting reflex was recorded as the time of anesthesia induction and awakening, respectively. The plasma concentration of Propofol was determined by gas chromatography- mass spectrometry. A pharmacokinetic analysis software was used to analyze the blood-drug concentrations and obtain the pharmacokinetic parameters. RESULTS: We observed that when Propofol anesthetizes rats, the anesthesia induction time was shortened, and the recovery time was prolonged with increased altitude. Compared with the plain group, the clearance of Propofol decreased, whereas the half-life, area under the concentration-time curve, peak plasma concentration, and average residence time extension increased. CONCLUSION: The pharmacokinetic characteristics of Propofol are significantly altered in high-altitude hypoxic environments.

High-level production of Rhodiola rosea characteristic component rosavin from D-glucose and L-arabinose in engineered Escherichia coli.

Rosavin is the characteristic component of Rhodiola rosea L., an important medicinal plant used widely in the world that has been reported to possess multiple biological activities. However, the endangered status of wild Rhodiola has limited the supply of rosavin. In this work, we successfully engineered an Escherichia coli strain to efficiently produce rosavin as an alternative production method. Firstly, cinnamate: CoA ligase from Hypericum calycinum, cinnamoyl-CoA reductase from Lolium perenne, and uridine diphosphate (UDP)-glycosyltransferase (UGT) from Bacillus subtilis (Bs-YjiC) were selected to improve the titer of rosin in E. coli. Subsequently, four UGTs from the UGT91R subfamily were identified to catalyze the formation of rosavin from rosin, with SlUGT91R1 from Solanum lycopersicum showing the highest activity level. Secondly, production of rosavin was achieved for the first time in E. coli by incorporating the SlUGT91R1 and UDP-arabinose pathway, including UDP-glucose dehydrogenase, UDP-xylose synthase, and UDP-xylose 4-epimerase, into the rosin-producing stain, and the titer reached 430.5 ± 91.4 mg/L. Thirdly, a two-step pathway derived from L-arabinose, composed of L-arabinokinase and UDP-sugar pyrophosphorylase, was developed in E. coli to further optimize the supply of the precursor UDP-arabinose. Furthermore, 1203.7 ± 32.1 mg/L of rosavin was produced from D-glucose and L-arabinose using shake-flask fermentation. Finally, the production of rosavin reached 7539.1 ± 228.7 mg/L by fed-batch fermentation in a 5-L bioreactor. Thus, the microbe-based production of rosavin shows great potential for commercialization. This work provides an effective strategy for the biosynthesis of other valuable natural products with arabinose-containing units from D-glucose and L-arabinose.

Metal-free radical bicyclization/chloroalkylarylation of 1,6-enynes with chloroalkanes.

Free radical initiated bicyclization of 1,6-enynes with chloralkanes, is achieved via selective activation of the C(sp3)-H bond of the chloralkane, resulting in diverse polychlorinated/chlorinated polyheterocycles. Two kinds of transformations and a scaled-up experiment were performed to test the synthetic importance of the organic chlorides. Finally, a range of radical inhibition operations and radical clock tests were explored to support the reaction process.

Ultrasensitive measurement of tactile force based on a PDMS-embedded microfiber Mach-Zehnder interferometer.

This study investigates the utilization of an in-fiber interferometer embedded in polydimethylsiloxane (PDMS) to develop a highly sensitive tactile sensor. The tapered mode-field mismatch structure is more conducive to stimulating strong high order modes to promote the sensitivity of the sensor. Experimental investigations are conducted to study the sensing performance of the sensor, resulting in a sensitivity of 23.636 nm/N and a detection limit of 0.746 mN. The experiments demonstrate that employing fast Fourier transform (FFT) and inverse FFT (IFFT) methods to filter weak high order modes significantly improves the repeatability of the sensor, resulting in a repeatability error of less than 1%.

Enzyme-free sensitive SERS biosensor for the detection of thalassemia-associated microRNA-210 using a cascade dual-signal amplification strategy.

BACKGROUND: ß-thalassemia is a blood disorder caused by autosomal mutations. Gene modulation therapy to activate the γ-globin gene to induce fetal hemoglobin (HbF) synthesis has become a new option for the treatment of ß-thalassemia. MicroRNA-210 (miR-210) contributes to studying the mechanism regulating γ-globin gene expression and is a potential biomarker for rapid ß-thalassemia screening. Traditional miRNA detection methods perform well but necessitate complex and time-consuming miRNA sample processing. Therefore, the development of a sensitive, accurate, and simple miRNA level monitoring method is essential. RESULTS: We have developed a non-enzymatic surface-enhanced Raman scattering (SERS) biosensor utilizing a signal cascade amplification of catalytic hairpin assembly reaction (CHA) and proximity hybridization-induced hybridization chain reaction (HCR). Au@Ag NPs were used as the SERS substrate, and methylene blue (MB)- modified DNA hairpins were used as the SERS tags. The SERS assay involved two stages: implementing the CHA-HCR cascade signal amplification strategy and conducting SERS measurements on the resulting product. The HCR was started by the products of target-triggered CHA, which formed lengthy nicked double-stranded DNA (dsDNA) on the Au@Ag NPs surface to which numerous SERS tags were attached, leading to a significant increase in the SERS signal intensity. High specificity and sensitivity for miR-210 detection was achieved by monitoring MB SERS intensity changes. The suggested SERS biosensor has a low detection limit of 5.13 fM and is capable of detecting miR-210 at concentration between 10 fM and 1.0 nM. SIGNIFICANCE: The biosensor can detect miR-210 levels in the erythrocytes of ß-thalassemia patients, enabling rapid screening for ß-thalassemia and suggesting a novel approach for investigating the regulation mechanism of miR-210 on γ-globin gene expression. In the meantime, this innovative technique has the potential to detect additional miRNAs and to become an important tool for the early diagnosis of diseases and for biomedical research.

A Suture Technique for Ruptured Annulus Fibrosus Following Decompression Under Percutaneous Transforaminal Endoscopic Discectomy.

The suture technique for a ruptured annulus fibrosus (AF) under full-endoscopy remains challenging. Direct suturing of a ruptured annular tear after full decompression has been shown to decrease the recurrence rate of lumbar disc herniation during endoscopic surgery. Traditional suture operations under endoscopy involve only simple suturing of the ruptured AF. Due to the weak and poor quality of the AF tissue around the tear portal, using this area as needle insertion points during suturing may lead to insufficient tension and a low success rate of AF closure. Currently, there is no detailed technical illustration based on video for AF tear suturing under lumbar full-endoscopy. We innovatively propose a method of covering and suturing the AF tear by pulling up the posterior longitudinal ligament (PLL) under lumbar endoscopy and using three stitches (PLL-AF suture technique). The patient who received the novel suture technique achieved satisfactory results. Six months after the operation, lumbar MRI showed no evidence of recurrence in the outpatient clinic.

A molecularly imprinted photoelectrochemical sensor based on an rGO/MoSSe heterojunction for the detection of chlortetracycline.

A reduced graphene oxide/molybdenum selenosulfide (rGO/MoSSe) heterojunction was synthesized, and a molecularly imprinted photoelectrochemical sensor for the detection of chlortetracycline was prepared. MoSSe was grown in situ on rGO by a hydrothermal method to form an rGO/MoSSe heterojunction, which acts as the sensitive film of the sensor. Since rGO can promote electron transfer and effectively inhibit electron-hole recombination, it effectively reduces the recombination probability of electrons and holes and improves the photoelectric efficiency, thus enhancing the detection sensitivity of the PEC sensor. The rGO/MoSSe was immobilized on an FTO electrode, and molecularly imprinted polymers (MIPs) were prepared by electropolymerization on the rGO/MoSSe-modified FTO electrode with chlortetracycline as the template molecule and o-phenylenediamine as the functional monomer, so as to construct a molecularly imprinted photoelectrochemical (MIP-PEC) sensor. The determination of chlortetracycline was realized by the strategy of a "gate-controlled effect", and the detection range of the chlortetracycline concentration was 5.0 × 10-13-5 × 10-9 mol L-1 with a detection limit of 1.57 × 10-13 mol L-1. The sensor has been applied to the determination of chlortetracycline in animal-derived food samples.

Determination of Aminophylline in Human Serum Using Hydrogel Microspheres for Coupled Surface-Enhanced Raman Spectroscopy (SERS) and Solid-Phase Extraction.

Aminophylline (AMP) is a bronchodilator. The therapeutic and toxic doses are very close. Therefore, therapeutic drug monitoring (TDM) of AMP is essential in clinical practice. Microgels were synthesized by free radical precipitation polymerization. Silver@poly(N-isopropyl acrylamide) (Ag@PNIPAM) hybrid microgels were obtained by loading silver (Ag) nanoparticles into the three-dimensional network of the microgels by in situ reduction. The microgel is a three-dimensional reticular structure with tunable pore size, large specific surface area, and good biocompatibility, which can be used as a sorbent for solid-phase extraction (SPE) of target molecules in complex matrices and as a surface-enhanced Raman spectroscopy (SERS) substrate. We optimized the conditions affecting SERS enhancement, such as silver nitrate (AgNO3) concentration and SPE time, according to the SERS strategy of Ag@PNIPAM hybrid microgels to achieve label-free TDM for trace AMP in human serum. The results showed good linearity between the logarithmic concentration of AMP and its SERS intensity in the range of 1-1.1 × 102 µg/mL, with a correlation coefficient (R2) of 0.9947 and a low detection limit of 0.61 µg/mL. The assay accuracy was demonstrated by spiking experiments, with recoveries ranging from 93.0 to 101.8%. The method is rapid, sensitive, reproducible, requires simple sample pretreatment, and has good potential for use in clinical treatment drug monitoring.

Regulating protein corona on nanovesicles by glycosylated polyhydroxy polymer modification for efficient drug delivery.

The dynamic protein corona formed on nanocarriers has been revealed to strongly affect their in vivo behaviors. Precisely manipulating the formation of protein corona on nanocarriers may provide an alternative impetus for specific drug delivery. Herein, we explore the role of glycosylated polyhydroxy polymer-modified nanovesicles (CP-LVs) with different amino/hydroxyl ratios in protein corona formation and evolution. CP-LVs with an amino/hydroxyl ratio of approximately 0.4 (CP1-LVs) are found to efficiently suppress immunoglobulin adsorption in blood and livers, resulting in prolonged circulation. Moreover, CP1-LVs adsorb abundant tumor distinctive proteins, such as CD44 and osteopontin in tumor interstitial fluids, mediating selective tumor cell internalization. The proteins corona transformation specific to the environment appears to be affected by the electrostatic interaction between CP-LVs and proteins with diverse isoelectric points. Benefiting from surface modification-mediated protein corona regulation, paclitaxel-loaded CP1-LVs demonstrate superior antitumor efficacy to PEGylated liposomes. Our work offers a perspective on rational surface-design of nanocarriers to modulate the protein corona formation for efficient drug delivery.

Association between dietary diversity, sedentary time outside of work and depressive symptoms among knowledge workers: a multi-center cross-sectional study.

BACKGROUND: Low-diversity diets and sedentary status are risk factors for depressive symptoms, while knowledge workers were ignored before. The purpose of this current study was to examine the relationship between dietary diversity, sedentary time spent outside of work, and depressive symptoms among knowledge workers. STUDY DESIGN AND METHODS: This was a multicenter and cross-sectional design that included 118,723 knowledge workers. Participants self-reported online between January 2018 and December 2020. Demographic information, the Dietary Diversity Scale, the Patient Health Questionnaire-9, dietary habits (which included eating three meals on time, midnight snacking, overeating, social engagement, coffee consumption, sugary drink consumption, smoking and alcohol use), sedentary time spent outside of work and physical activity were investigated. RESULTS: The relationships between demographic information, dietary habits and dietary diversity, and depressive symptoms were estimated. Compared with the first and second levels of dietary diversity, the third level of dietary diversity (OR: 0.91; 95% CI: 0.84-0.98) reduced the risk of depressive symptoms. Knowledge workers with different degrees of sedentary status (2-4 h (OR: 1.11; 95% CI: 1.07-1.14), 4-6 h (OR: 1.21; 95% CI: 1.17-1.26), and > 6 h (OR: 1.49; 95% CI: 1.43-1.56), presented a progressively higher risk of depressive symptoms. CONCLUSION: High amounts of sedentary time spent after work and low levels of dietary diversity are risk factors for depressive symptoms. In addition, an irregular diet and overeating are also major risk factors for knowledge workers.

Biosynthesis of eriodictyol in citrus waster by endowing P450BM3 activity of naringenin hydroxylation.

The flavonoid naringenin is abundantly present in pomelo peels, and the unprocessed naringenin in wastes is not friendly for the environment once discarded directly. Fortunately, the hydroxylated product of eriodictyol from naringenin exhibits remarkable antioxidant and anticancer properties. The P450s was suggested promising for the bioconversion of the flavonoids, but less naturally existed P450s show hydroxylation activity to C3' of the naringenin. By well analyzing the catalytic mechanism and the conformations of the naringenin in P450, we proposed that the intermediate Cmpd I ((porphyrin)Fe = O) is more reasonable as key conformation for the hydrolyzation, and the distance between C3'/C5' of naringenin to the O atom of CmpdI determines the hydroxylating activity for the naringenin. Thus, the "flying kite model" that gradually drags the C-H bond of the substrate to the O atom of CmpdI was put forward for rational design. With ab initio design, we successfully endowed the self-sufficient P450-BM3 hydroxylic activity to naringenin and obtained mutant M5-5, with kcat, Km, and kcat/Km values of 230.45 min-1, 310.48 µM, and 0.742 min-1 µM-1, respectively. Furthermore, the mutant M4186 was screened with kcat/Km of 4.28-fold highly improved than the reported M13. The M4186 also exhibited 62.57% yield of eriodictyol, more suitable for the industrial application. This study provided a theoretical guide for the rational design of P450s to the nonnative compounds. KEY POINTS: •The compound I is proposed as the starting point for the rational design of the P450BM3 •"Flying kite model" is proposed based on the distance between O of Cmpd I and C3'/C5' of naringenin •Mutant M15-5 with 1.6-fold of activity than M13 was obtained by ab initio modification.

Pyroptosis-Related Gene Signature Predicts Prognosis and Response to Immunotherapy and Medication in Pediatric and Young Adult Osteosarcoma Patients.

Purpose: Pyroptosis, a new form of inflammatory programmed cell death, has recently gained attention. However, the impact of the expression levels of pyroptosis-related genes (PRGs) on the overall survival (OS) of osteosarcoma patients remains unclear. This study aims to investigate the impact of the expression levels of PRGs on the OS of pediatric and young adult patients with osteosarcoma. Patients and Methods: Transcriptome matrix datasets of normal muscle or skeletal tissues from the Genotype-Tissue Expression (GTEx) project and osteosarcoma specimen the National Cancer Institute's (NCI) Therapeutically Applicable Research to Generate Effective Treatments (TARGET) database were used to identify pyroptosis-related genes (PRGs) associated with prognosis. The National Center for Biotechnology Information's (NCBI) GSE21257 dataset was employed to validate the predictive value of the pyroptosis-related signature (PRS). Additionally, reverse transcription polymerase chain reaction (RT-qPCR) experiment was performed in normal and osteosarcoma cell lines. Results: The study identified 18 differentially expressed PRGs (DEPRGs) between normal muscle or skeletal tissues and tumor samples. Multiple machine learning techniques were used to select PRGs, resulting in the identification of four hub PRGs. A PRS-score was calculated for each sample based on the expression of these four hub PRGs, and samples were categorized into low and high PRS-score level groups. It was confirmed that metastatic status and PRS-score level are independent prognostic predictors. A nomogram model for predicting OS of osteosarcoma patients was constructed. Single-cell RNA-sequencing data display the expression patterns of the hub PRGs. RT-qPCR data results were found to be consistent with the differential expression analysis performed on TARGET and GTEx samples. Conclusion: The study developed a novel pyroptosis-related gene signature that can stratify pediatric and young adult osteosarcoma patients into different risk groups, thus predicting their response to immunotherapy and chemotherapy.