Immobilized enzyme-based enzyme electrode biosensors, characterized by high sensitivity and efficiency, strong specificity, and compact size, demonstrate broad application prospects in life science research, disease diagnosis and monitoring, etc. Immobilization of enzyme is a critical step in determining the performance (stability, sensitivity, and reproducibility) of the biosensors. Random immobilization (physical adsorption, covalent cross-linking, etc.) can easily bring about problems, such as decreased enzyme activity and relatively unstable immobilization. Whereas, directional immobilization utilizing amino acid residue mutation, affinity peptide fusion, or nucleotide-specific binding to restrict the orientation of the enzymes provides new possibilities to solve the problems caused by random immobilization. In this paper, the principles, advantages and disadvantages and the application progress of enzyme electrode biosensors of different directional immobilization strategies for enzyme molecular sensing elements by specific amino acids (lysine, histidine, cysteine, unnatural amino acid) with functional groups introduced based on site-specific mutation, affinity peptides (gold binding peptides, carbon binding peptides, carbohydrate binding domains) fused through genetic engineering, and specific binding between nucleotides and target enzymes (proteins) were reviewed, and the application fields, advantages and limitations of various immobilized enzyme interface characterization techniques were discussed, hoping to provide theoretical and technical guidance for the creation of high-performance enzyme sensing elements and the manufacture of enzyme electrode sensors.

Nine compounds were isolated and purified from 90% ethanol extract of Alstonia mairei Lévl by using various chromatographic methods, including silica gel, SephadexLH-20, MCI Gel and ODS column chromatography, combined with semi-preparative liquid phase separation methods. Modern spectroscopic methods (1D and 2D NMR, UV, IR, MS, etc.) were used to identify the structures of the isolated compounds. They were identified as mairoside A (1), 3′,6-di-O-sinaloylsucrose (2), myristic acid (3), methyl myristate (4), ethyl myristate (5), 3,4,5-trimethoxycinnamic acid (6), 3,4,5-trimethoxybenzoic acid (7), vinoline (8), kaempferol-3-O-rutinoside (9), among which compound 1 is a new glycoside, compounds 4 and 5 are new natural products, and the nuclear magnetic data of compound 4 were reported for the first time.

ObjectiveTo explore the role and potential mechanism of circulating glutamate in enhancing insulin sensitivity by aerobic exercise. This research may provide a novel strategy for preventing metabolic diseases through precise exercise interventions. MethodsTo investigate the effects of elevated circulating glutamate on insulin sensitivity and its potential mechanisms, 18 male C57BL/6 mice aged 6 to 8 weeks were randomly divided into 3 groups: a control group (C), a group receiving 500 mg/kg glutamate supplementation (M), and a group receiving 1 000 mg/kg glutamate supplementation (H). The intervention lasted for 12 weeks, with treatments administered 6 d per week. Following the intervention, an insulin tolerance test (ITT) and a glucose tolerance test (GTT) were conducted. Circulating glutamate levels were measured using a commercial kit, and the activity of the skeletal muscle InsR/IRS1/PI3K/AKT signaling pathway was analyzed via Western blot. To further investigate the role of circulating glutamate in enhancing insulin sensitivity through aerobic exercise, 30 male C57BL/6 mice were randomly assigned to 3 groups: a control group (CS), an exercise intervention group (ES), and an exercise combined with glutamate supplementation group (EG). The ES group underwent treadmill-based aerobic exercise, while the EG group received glutamate supplementation at a dosage of 1 000 mg/kg in addition to aerobic exercise. The intervention lasted for 10 weeks, with sessions occurring 6 d per week, and the same procedures were followed afterward. To further elucidate the mechanism by which glutamate modulates the InsR/IRS1/PI3K/AKT signaling pathway, C2C12 myotubes were initially subjected to graded glutamate treatment (0, 0.5, 1, 3, 5, 10 mmol/L) to determine the optimal concentration for cellular intervention. Subsequently, the cells were divided into 3 groups: a control group (C), a glutamate intervention group (G), and a glutamate combined with MK801 (an NMDA receptor antagonist) intervention group (GK). The G group was treated with 5 mmol/L glutamate, while the GK group received 50 μmol/L MK801 in addition to 5 mmol/L glutamate. After 24 h of intervention, the activity of the InsR/IRS1/PI3K/AKT signaling pathway was analyzed using Western blot. ResultsCompared to the mice in group C, the circulating glutamate levels, the area under curve (AUC) of ITT, and the AUC of GTT in the mice of group H were significantly increased. Additionally, the expression levels of p-InsRβ, IRS1, p-AKT, and p-mTOR proteins in skeletal muscle were significantly downregulated. Compared to the mice in group CS, the circulating glutamate levels, the AUC of ITT, and the AUC of GTT in the mice of group ES were significantly reduced. Additionally, the expression levels of p-InsRβ, IRS1, p-AKT, and p-mTOR proteins in skeletal muscle of group ES mice were significantly upregulated. There were no significant changes observed in the mice of group EG. Compared to the cells in group 0 mmol/L, the expression levels of p-InsRβ, p-IRS1, p-PI3K, and p-AKT proteins in cells of group 5 mmol/L were significantly downregulated. Compared to the cells in group C, the expression levels of p-InsRβ, p-IRS1, p-PI3K, and p-AKT proteins in the cells of group G were significantly downregulated. No significant changes were observed in the cells of group GK. ConclusionLong-term aerobic exercise can improve insulin sensitivity by lowering circulating levels of glutamate. This effect may be associated with the upregulation of the InsR/IRS1/AKT signaling pathway activity in skeletal muscle. Furthermore, glutamate can weaken the activity of the InsR/IRS1/PI3K/AKT signaling pathway in skeletal muscle, potentially by binding to NMDAR expressed in skeletal muscle.

ObjectiveTo investigate how Xiaoyao Shukun decoction （XYSKD） regulates the formation and release of neutrophil extracellular traps （NETs） via the phosphatidylinositol 3-kinase （PI3K）/protein kinase B （Akt）/mammalian target of rapamycin （mTOR） signaling pathway， thereby reducing inflammation， inhibiting the excessive proliferation of fibroblasts in pelvic adhesion tissue， decreasing adhesion and fibrosis， and repairing the tissue damage in sequelae of pelvic inflammatory disease （SPID）. MethodsA total of 84 Wistar rats were randomly allocated into seven groups： blank， model， XYSKD （8 mg·kg^-1）， mTOR agonist （10 mg·kg^-1）， mTOR agonist + XYSKD （10 mg·kg^-1+8 mg·kg^-1）， mTOR inhibitor （2 mg·kg^-1）， and mTOR inhibitor + XYSKD （2 mg·kg^-1+8 mg·kg^-1）. The rat model of SPID was constructed by starvation， fatigue， and ascending Escherichia coli infection. After 14 days of drug intervention， the ultrastructure of fibroblasts in the pelvic adhesion tissue was observed by transmission electron microscopy. The general morphology of the uterus， fallopian tube， and ovary was observed by laparotomy. The levels of interleukin-1β （IL-1β）， interleukin-17 （IL-17）， and tumor necrosis factor-α （TNF-α） in the peritoneal flushing fluid were determined by enzyme-linked immunosorbent assay （ELISA）. The expression of myeloperoxidase （MPO） and citrullinated histone 3 （H3） in the fallopian tube was detected by immunofluorescence. Western blot and Real-time quantitative polymerase chain reaction （Real-time PCR） were employed to determine the relative protein and mRNA levels， respectively， of neutrophil elastase （NE）， intercellular adhesion molecule-1 （CD54）， α-smooth muscle actin （α-SMA）， H3， PI3K， and Akt. ResultsCompared with the blank group， the model group presented a large number of collagen fibers in bundles， numerous cytoplasmic folds of fibroblasts， reduced or absent mitochondrial cristae， and disordered and expanded endoplasmic reticulum. By laparotomy， extensive pelvic congestion， connective tissue hyperplasia， thickening and hardening of the tubal end near the uterus， and tubal and ovarian adhesion or cyst were observed in the model group. In addition， the model group showed raised levels of IL-1β， IL-17， and TNF-α in the peritoneal flushing fluid （P<0.01）， increased average fluorescence intensities of MPO and H3 （P<0.01）， and up-regulated protein and mRNA levels of NE， H3， CD54， PI3K， and Akt （P<0.01）. Compared with the model group， the mTOR agonist group showed increased fibroblasts and cytoplasmic folds， absence of mitochondrial cristae， endoplasmic reticulum dilation， and evident collagen fiber hyperplasia. Pelvic adhesions were observed to cause aggravated damage to the uterine， fallopian tube， and ovarian tissues. The levels of IL-1β， IL-17， and TNF-α in the peritoneal lavage fluid elevated （P<0.01） and the average fluorescence intensities of MPO and H3 enhanced （P<0.01） in the mTOR agonist group. In contrast， the XYSKD group and the mTOR inhibitor group showcased decreased fibroblasts and collagen fibers， alleviated mitochondrial crista loss and endoplasmic reticulum dilation， improved morphology and appearance of the uterine， fallopian tube， and ovarian tissues， lowered levels of IL-1β， IL-17， and TNF-α in the peritoneal lavage fluid （P<0.01）， decreased average fluorescence intensities of MPO and H3 （P<0.01）， and down-regulated protein and mRNA levels of NE， H3， CD54， PI3K， and Akt （P<0.05）. Compared with the mTOR agonist group， the mTOR agonist + XYSKD group showed alleviated pathological changes in the pelvic tissue， declined levels of IL-1β， IL-17， and TNF-α （P<0.01）， decreased average fluorescence intensities of MPO and H3 （P<0.01）， and down-regulated protein levels of NE， H3， CD54， α-SMA， p-PI3K/PI3K， and p-Akt/Akt （P<0.01） and mRNA levels of NE， H3， CD54， α-SMA， PI3K， and Akt （P<0.01）. Compared with the mTOR inhibitor group， the mTOR inhibitor + XYSKD group demonstrated reduced pathological severity of the pelvic tissue， reduced levels of IL-1β， IL-17， and TNF-α （P<0.01）， decreased average fluorescence intensities of MPO and H3 （P<0.01）， and down-regulated protein and mRNA levels of NE and CD54 （P<0.05）. ConclusionXYSKD can inhibit the excessive formation and release of NETs via PI3K/Akt/mTOR to ameliorate the inflammatory environment and reduce fibrosis and adhesion of the pelvic tissue， thereby playing a role in the treatment of SPID. It may exert the effects by lowering the levels of IL-1β， IL-17， and TNF-α and down-regulating the expression of NE， H3， CD54， α-SMA， PI3K， and Akt in the pelvic adhesion tissue.

Ten compounds were isolated and purified from ethanol extracts of dried roots bark of Polygala tenuifolia Willd. by various chromatography techniques such as silica gel and Sephadex LH-20. Their structures were identified by analysis of physicochemical properties and spectral data, and determined as β-sitosterol (1), tenuifolin (2), 6-methoxy coumarin (3), 7-phenyl-1-hydroxy-2,3,6-trimethoxyxanthone (4), 1,8-dihydroxy-3,4,7-trimethoxyanthone (5), mangiferin (6), quercetin-3-O-β-D-glucoside (7), rutin (8), syringaldehyde (9), salicylicacid (10). Among them, compounds 3, 4 and 5 were isolated from the genus of Ploygala for the first time and compound 4 was a new xanthone. The acetylcholinesterase inhibitory activities of compounds 3, 4 and 5 were evaluated by Ellman colorimetric method, compounds 3 and 5 exhibited moderate inhibitory activity, compound 4 exhibited weak inhibitory activity.

Using the liquid chromatography-tandem mass spectrometry (LC-MS/MS) to determine the plasma level of Lyso-GL3 in patients with Fabry disease and to analyze the clinical application of the method.

Objective To analyze the clinical manifestations and epidemiological characteristics of influenza in Hubei. Methods Pharyngeal swab specimens from 16,500 patients with suspected influenza infection admitted to our hospital from January 2020 to December 2022 were selected. Viral detection and serotyping were performed by fluorescence quantitative polymerase chain reaction. Furthermore, the epidemiological and clinical data of patients were collected to analyze the clinical features and epidemiological characteristics of influenza viruses. Results A total of 16 500 clinical specimens were tested in this study, with a positive detection rate of 16.27% (2 684/16 500). The positive detection rate was 5.10% (862/16 500) for influenza A virus, 10.13% (1 672/16 500) for influenza B virus and 0.91% (150/16 500) for mixed influenza. The positive detection rate of influenza viruses was on the rise from 2020 to 2022 , reaching 18.43% in 2022. Seasonal distribution analysis denoted that the highest positive detection rates were observed in spring (18.23%) and winter (19.72%), with statistical difference (P<0.05). In terms of age distribution, patients<12 years (19.14%) had the highest positive detection rate, followed by those >60 years (17.71%), with statistical difference (P<0.05). From 2020 to 2022, the positive detection rate of influenza virus was 16.89% in males, which was higher than 15.63% in females (P<0.05). The main clinical symptoms were fever (86.89%) and cough (80.27%) for influenza A virus infections, cough (92.52%) and fever (86.06%) for influenza B virus infections, and cough (94.00%), fever (88.00%) and runny nose (86.00%) for mixed infections. Conclusion The influenza B viruses are the leading cause of influenza in Hubei from 2020 to 2022, and the infection demonstrates an increasing annual trend, with a high prevalence in winter and spring. Furthermore, children and the elderly are high-risk populations, and clinical manifestions are mainly cough and fever.

The toad, known for its various medicinal properties including parotid gland secretion (toad venom), dried skin, and gallbladder (toad bile), holds considerable medicinal applications as a valuable traditional Chinese animal medicine. Currently, in-depth attentions have been paid to the chemical composition and pharmacological properties of toad venom and skin; however, a lesser number of detailed analyses were concentrated on the toad bile. This review provides an overview of the chemical constituents in the bile of the Bufo genus, with a special focus on the cholestane and bufadienolides, and highlights the progress in their biosynthetic pathway and pharmacological activities. The analysis uncovers a distinct category of unsaturated Δ²² or Δ²³-C₂₇/C₂₈ bile acids in the toad gallbladder, potentially acting as key intermediaries in forming C-17 α-pyrone of bufadienolides. Furthermore, the high presence of 3α-OH configured bufadienolides in toad bile, in contrast to the common 3β-OH configured found in toad venom or skin, indicates a possible link between their minimal toxicity and the toad's self-defensive or physiological control. This review provides scientific basis for the development and utilization of toad bile resources, and provides useful reference for the discovery of lead compounds, analysis of the biosynthetic pathway of bufadienolides, and research on toad physiology.

BACKGROUND:Hydroxyapatite is the main inorganic component of bone tissue.The polymer has the structure and function of a biomimetic extracellular matrix.The composites of hydroxyapatite and polymer have been widely studied. OBJECTIVE:To summarize the research status of hydroxyapatite composite polymer materials for bone tissue repair. METHODS:The articles collected in PubMed,Web of Science,CNKI and WanFang databases were searched from January 2010 to April 2023.The Chinese and English search terms were"hydroxyapatite,polymer,composites,degradability,bone defect,bone repair".Finally,75 articles were included for review. RESULTS AND CONCLUSION:Polymers often used in composite with hydroxyapatite for bone tissue repair include natural polymers(collagen,chitosan,alginate,serine protein,cellulose,hyaluronic acid,and polyhydroxybutyrate)and synthetic polymers[polylactic acid,polylactic acid-hydroxyacetic acid copolymer,poly(has-lactide),poly(amino acid)and poly(vinyl alcohol)].The mechanical properties and osteoinductivity of hydroxyapatite/polymer composites were improved compared with pure hydroxyapatite.Hydroxyapatite composite with polymers can be made into porous scaffolds,hydrogels,and coatings for bone repair.Hydroxyapatite/polymer composites can accelerate bone reconstruction with a slow release of loaded drugs and cytokines due to their bionic extracellular matrix structure and function.Based on the diversity of causes of bone defects and the fact that bone repair is a complex continuous process involving multiple biological factors and proteins,repair materials with mechanical properties matching bone tissue,degradation processes synchronized with bone repair,and efficient osteogenesis and vascularization need to be further investigated.

AIM:Bone morphogenetic protein 7(BMP7)reduces the expression of Yes-related protein 1(YAP1)by down-regulating Ajuba level and decreasing extracellular matrix(ECM)deposition.This study aimed to inves-tigate the influence of these factors on modifying the degree of renal fibrosis in rats with diabetic nephropathy.METH-ODS:Eighteen Sprague-Dawley(SD)rats were randomly divided into three groups:the normal control(NC)group,the diabetes mellitus(DM)group,and the DM group treated with BMP7 overexpressing adeno-associated virus(DM+rAAV-BMP7).Each group consisted of six rats.Diabetic kidney disease(DKD)was established in the DM and DM+rAAV-BMP7 groups by injecting 55 mg/kg streptozotocin(STZ)via the tail vein.NRK-52E cells were divided into three groups:the normal glucose(NG)group,the high glucose(HG)group,and the high glucose group treated with recombinant hu-man BMP7(HG+rhBMP7)group.Pathological changes in renal tissues were observed using hematoxylin and eosin(HE)and Sirius red staining.Immunohistochemical staining was performed to examine the expression sites of Ajuba and YAP1 in the renal cortex.Western blot analysis was conducted to determine the expression levels of BMP7,Ajuba,YAP1,colla-gen type Ⅲ(Col-Ⅲ),and fibronectin(FN)in the rat renal cortex and NRK-52E cells.RT-qPCR was used to measure the mRNA levels of Ajuba and YAP1 in the rat renal cortex.RESULTS:Biochemical indices revealed significantly ele-vated levels of blood glucose,serum creatinine,triglycerides,total cholesterol,and 24-hour urinary protein in the DM group compared to the NC group(P<0.05).In the DM+rAAV-BMP7 group,the levels of serum creatinine,24-hour uri-nary protein,triglycerides,and total cholesterol were lower than those in the DM group(P<0.05).Pathological staining demonstrated that the renal interstitium of the DM group exhibited inflammatory cell infiltration,fibrous tissue,collagen fi-ber deposition,disordered renal tubule arrangement,atrophy,and vacuolar degeneration,which were ameliorated in the DM+rAAV-BMP7 group.Immunohistochemistry revealed that Ajuba and YAP1 were mainly expressed in the cytoplasm and nucleus,with high expression in the cytoplasm of the DM group,which was significantly decreased in the DM+rAAV-BMP7 group.Western blot results indicated that the protein levels of FN,Col-Ⅲ,Ajuba,and YAP1 were up-regulated in the DM and the HG groups(P<0.05),but significantly down-regulated in the DM+rAAV-BMP7 group(P<0.05).RT-qP-CR results demonstrated that the mRNA levels of Ajuba and YAP1 were higher in the DM group and significantly lower in the DM+rAAV-BMP7 group(P<0.05).CONCLUSION:The overexpression of BMP7 can ameliorate renal fibrosis in rats with DKD.This effect is likely mediated by the down-regulation of Ajuba,reduction of YAP1 expression,and subse-quent inhibition of ECM deposition.