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.

Collagen is a major structural protein in the matrix of animal cells and the most widely distributed and abundant functional protein in mammals. Collagen’s good biocompatibility, biodegradability and biological activity make it a very valuable biomaterial. According to the source of collagen, it can be broadly categorized into two types: one is animal collagen; the other is recombinant collagen. Animal collagen is mainly extracted and purified from animal connective tissues by chemical methods, such as acid, alkali and enzyme methods, etc. Recombinant collagen refers to collagen produced by gene splicing technology, where the amino acid sequence is first designed and improved according to one’s own needs, and the gene sequence of improved recombinant collagen is highly consistent with that of human beings, and then the designed gene sequence is cloned into the appropriate vector, and then transferred to the appropriate expression vector. The designed gene sequence is cloned into a suitable vector, and then transferred to a suitable expression system for full expression, and finally the target protein is obtained by extraction and purification technology. Recombinant collagen has excellent histocompatibility and water solubility, can be directly absorbed by the human body and participate in the construction of collagen, remodeling of the extracellular matrix, cell growth, wound healing and site filling, etc., which has demonstrated significant effects, and has become the focus of the development of modern biomedical materials. This paper firstly elaborates the structure, type, and tissue distribution of human collagen, as well as the associated genetic diseases of different types of collagen, then introduces the specific process of producing animal source collagen and recombinant collagen, explains the advantages of recombinant collagen production method, and then introduces the various systems of expressing recombinant collagen, as well as their advantages and disadvantages, and finally briefly introduces the application of animal collagen, focusing on the use of animal collagen in the development of biopharmaceutical materials. In terms of application, it focuses on the use of animal disease models exploring the application effects of recombinant collagen in wound hemostasis, wound repair, corneal therapy, female pelvic floor dysfunction (FPFD), vaginal atrophy (VA) and vaginal dryness, thin endometritis (TE), chronic endometritis (CE), bone tissue regeneration in vivo, cardiovascular diseases, breast cancer (BC) and anti-aging. The mechanism of action of recombinant collagen in the treatment of FPFD and CE was introduced, and the clinical application and curative effect of recombinant collagen in skin burn, skin wound, dermatitis, acne and menopausal urogenital syndrome (GSM) were summarized. From the exploratory studies and clinical applications, it is evident that recombinant collagen has demonstrated surprising effects in the treatment of all types of diseases, such as reducing inflammation, promoting cell proliferation, migration and adhesion, increasing collagen deposition, and remodeling the extracellular matrix. At the end of the review, the challenges faced by recombinant collagen are summarized: to develop new recombinant collagen types and dosage forms, to explore the mechanism of action of recombinant collagen, and to provide an outlook for the future development and application of recombinant collagen.

ObjectiveTo characterize the seasonal patterns of influenza in Kunming City, Yunnan Province before, during, and after the COVID-19 pandemic, and provide scientific evidence for optimizing influenza prevention and control strategies. MethodsInfluenza-like illness (ILI) and etiological surveillance data for influenza from the 14^th week of 2010 to the 13^th week of 2024 in Kunming City of Yunnan Province were collected. Harmonic regression models were constructed to analyze the epidemic characteristics and seasonal patterns of influenza before (2010/2011‒2019/2020 influenza seasons), during (2020/2021‒2022/2023 influenza seasons), and after (2023/2024 influenza season) the COVID-19 pandemic. ResultsBefore the COVID-19 pandemic, influenza in Kunming City mainly exhibited an annual cyclic pattern without a significant semi-annual periodicity, peaking from December to February of the next year, with an epidemic duration of 20‒30 weeks. During the pandemic, influenza seasonality shifted, with an increase in semi-annual periodicity and an approximate one month delay in annual peaks. However, after the pandemic, the annual amplitude of influenza increased compared with that before the pandemic, and the epidemic duration extended by about one month. Although the annual peak largely reverted to the pre-pandemic levels, the annual peaks for different influenza subtypes/lineages had not fully recovered. ConclusionInfluenza seasonality in Kunming City underwent substantial alterations following the COVID-19 pandemic and has not yet fully reverted to pre-pandemic levels. Continuous surveillance on different subtypes/lineages of influenza viruses remains essential, and prevention and control strategies should be adjusted and optimized in a timely manner based on current epidemic trends.

The hippocampus, a major component of the limbic system, is the most important region related to emotion regulation and memory processing. Cognitive impairment and depressive symptoms observed in Alzheimer's disease (AD) patients may be attributed to hippocampal damage caused by amyloid β-protein (Aβ). Our previous studies have demonstrated that a steroid sulfatase inhibitor DU-14 can enhance hippocampal synaptic plasticity and spatial memory abilities in a chronic AD murine model by counteracting the toxic effects of Aβ. However, limited experimental evidence exists regarding the efficacy of steroid sulfatase inhibitor on depressive symptoms in AD animal models. In this study, we investigated the effects of DU-14 on depressive symptoms and theta-band neuronal oscillations in rats with intrahippocampal injection of Aβ_1-42 using various behavioral tests such as sucrose preference test, tail suspension test, forced swimming test, and in vivo hippocampal local field potential (LFP) recording. The results demonstrated that, in comparison to the control group: (1) rats in the Aβ group exhibited a decrease in sucrose preference, indicating a loss of interest in pleasurable activities; (2) rats in the Aβ group displayed aggravated depressive-like behavior characterized by prolonged immobility time during tail suspension and forced swimming tests; (3) Aβ disrupted the induction of theta rhythm via tail pinch stimulation, and resulted in a significant reduction in peak power of theta rhythm. In contrast to the Aβ group, pretreatment with DU-14 resulted in: (1) a significant improvement in Aβ-induced anhedonia, as evidenced by increased sucrose preference; (2) significant alleviation of Aβ-induced despair and depressive-like behaviors, reflected by reduced immobility time during tail suspension and forced swimming tests; (3) successful mitigation of Aβ-mediated inhibition on bilateral hippocampal theta rhythm. These findings indicate that steroid sulfatase inhibitor DU-14 can counteract neurotoxicity induced by Aβ, and prevent Aβ-induced depressive-like behavior and suppression of theta rhythm.
Animals ; Amyloid beta-Peptides/toxicity* ; Rats ; Depression/physiopathology* ; Theta Rhythm/drug effects* ; Hippocampus/physiopathology* ; Male ; Rats, Sprague-Dawley ; Alzheimer Disease/physiopathology* ; Steryl-Sulfatase/antagonists & inhibitors* ; Peptide Fragments ; Behavior, Animal/drug effects*

To study the ameliorative effect of Eucommiae Cortex extract on spatial learning disabilities in APP/PS1 double-transgenic mice and explore its relationship with estrogen receptor β(ERβ)/c-Jun N-terminal kinase(JNK) signaling pathway, sixty 3-month-old male APP/PS1 mice were randomly divided into a model group, an anti-brain failure capsule group(0.585 g·kg~(-1)), a donepezil hydrochloride group(0.65 mg·kg~(-1)), and a Eucommiae Cortex extract group(1.3 g·kg~(-1)), and 15 C57BL/6 mice of the same genetic background were set as WT control group. The learning and memory ability of mice was assessed by the Morris water maze test(MWM), the passive avoidance test(PAT), and the novel object recognition test(NOR). The histomorphological and cellular ultrastructural features of the hippocampal region of the mice were observed by hematoxylin-eosin(HE) staining and transmission electron microscopy(TEM); the molecular docking validation of the key active ingredients and the key targets was performed by using AutoDock Vina software, and the immunohistochemical method(IHC) was used to detect the ERβ expression in the dentate gyrus(DG) area of mouse hippocampus. Western blot(WB) was utilized to detect the expression of ERβ, p-JNK, and JNK in mouse hippocampal area. Compared with those in the WT control group, the results of behavioral experiments showed that the latency of the mice in the model group was significantly increased, the number of platform traversals, and the target quadrant residence time were significantly decreased in the MWM. The evasion latency was significantly reduced, and the number of errors was significantly increased in the PAT. The index of recognition of novel objects was significantly reduced in the NOR. The results of HE staining indicated that the hippocampal area of mice in the model group showed a decrease in the number of neurons, disorganization of pyramidal cell arrangement, nucleus consolidation, and other changes. TEM results showed that some neuronal nuclei in the hippocampal area had a consolidated state, slightly thickened and aberrant nuclear membranes, and fewer intracytoplasmic nidus bodies; the IHC results showed that the expression of ERβ in the hippocampal DG area of the mice was reduced. The WB results showed that the ERβ expression in the hippocampal tissue was decreased, and the p-JNK/JNK level was elevated. Compared with the model group, the Eucommiae Cortex extract group showed a significant decrease in latency, and increase in number of platform traversals and target quadrant residence time in the MWM, a significant increase in evasion latency and decrease in number of errors in the PAT, and a significant increase in the index of recognition of novel objects in the NOR. In addition, there was an increase in the number of neurons in the hippocampal area of mice. The pyramidal cells tended to be arranged in an orderly manner; the nuclei of neurons in the hippocampal area were in a better state; the expression of ERβ in the hippocampal DG area of the mice was elevated; the expression of ERβ in the hippocampal tissue was elevated, and the level of p-JNK/JNK was reduced. The effects of donepezil hydrochloride group and anti-brain failure capsule on APP/PS1 mice in terms of behavioral, HE, and TEM indexes were similar to those of Eucommiae Cortex extract, and there was no significant difference between donepezil hydrochloride group and the model group in IHC and WB experiments, and the results of molecular docking indicated that the estrogen-like components in Eucommiae Cortex extract were tightly bound to ERβ. In conclusion, the binding of Eucommiae Cortex extract to estrogen receptors, regulation of ERβ expression, and activation of ERβ/JNK signaling pathway may be one of the key mechanisms by which it improves the learning and memory ability of APP/PS1 mice.
Animals ; Male ; Mice ; Mice, Transgenic ; Memory/drug effects* ; Mice, Inbred C57BL ; Estrogen Receptor beta/genetics* ; Eucommiaceae/chemistry* ; Alzheimer Disease/psychology* ; Amyloid beta-Protein Precursor/metabolism* ; Presenilin-1/metabolism* ; Humans ; MAP Kinase Signaling System/drug effects* ; Drugs, Chinese Herbal/administration & dosage* ; Hippocampus/metabolism* ; Maze Learning/drug effects* ; Learning/drug effects*

This study aimed to compare the ameliorative effects of Lycii Fructus and Chrysanthemi Flos at different ratios on retinal damage in mice and to elucidate the underlying mechanisms. A retinal injury model was established by intraperitoneal injection of sodium iodate(NaIO_3) solution. The mice were divided into the following groups: blank group, model group, positive drug(AREDS 2) group, low-and high-dose groups of Lycii Fructus and Chrysanthemi Flos at 1∶1, low-and high-dose groups at 3∶1, and low-and high-dose groups at 1∶3. Administration was carried out 15 days after modeling. The visual acuity of the mice was assessed using the black-and-white box test. The fundus was observed using an optical coherence tomography device, and retinal thickness was measured. HE staining was used to observe the morphology and pathological changes of the retina. The levels of oxidative factors in serum and ocular tissues were measured using assay kits. The levels of inflammatory factors in serum and ocular tissues were detected by enzyme-linked immunosorbent assay(ELISA), and the expression of Nrf2, HO-1, and NF-κB proteins in ocular tissues was analyzed by Western blot. The results showed that after administration of Lycii Fructus and Chrysanthemi Flos at different ratios, the model group showed improved retinal thinning and disordered arrangement of retinal layers, elevated content of SOD and GSH in the serum and ocular tissues, and reduced levels of MDA, TNF-α, IL-1β, and IL-6. Lycii Fructus and Chrysanthemi Flos at 1∶1 and 1∶3 showed better improvement effects. The combination significantly upregulated the expression levels of Nrf2 and HO-1 and downregulated the expression of NF-κB p65. These results indicate that Lycii Fructus and Chrysanthemi Flos at different ratios can improve retinal damage, reduce oxidative stress, and alleviate inflammation in both the body and ocular tissues of mice. The mechanism may be related to the regulation of the Nrf2/HO-1 and NF-κB signaling pathways in ocular tissues. These findings provide a theoretical basis for the clinical application of Lycii Fructus and Chrysanthemi Flos in the treatment of dry age-related macular degeneration.
Animals ; Mice ; Retina/injuries* ; Male ; Lycium/chemistry* ; Drugs, Chinese Herbal/administration & dosage* ; Chrysanthemum/chemistry* ; NF-kappa B/genetics* ; Humans ; Retinal Diseases/metabolism* ; NF-E2-Related Factor 2/metabolism* ; Oxidative Stress/drug effects* ; Flowers/chemistry* ; Heme Oxygenase-1/genetics*

In order to compare the differences in growth and secondary metabolite accumulation of Panax quinquefolius between understory and field planting, growth indexes, photosynthetic characteristics, soil enzyme activities, secondary metabolite contents, and antioxidant activities of P. quinquefolius under different planting modes were examined and compared, and One-way analysis of variance(ANOVA) and correlation analyses were carried out by using the software SPSS 25.0 and GraphPad Prism 9.5. The Origin 2021 software was used for plotting. The results showed that compared with those under field planting, the plant height, leaf length, leaf width, photosynthetic rate, and chlorophyll content of P. quinquefolius under understory planting were significantly reduced, and arbuscular mycorrhizal fungi(AMF) infestation rate and infestation intensity, ginsenoside content, and antioxidant activity were significantly increased. The activities of inter-root soil urease, sucrase, and catalase increased, while the activities of non-inter-root soil urease and alkaline phosphatase increased. Correlation analyses showed that the plant height and leaf length of P. quinquefolius plant were significantly positively correlated with net photosynthetic rate, transpiration rate, chlorophyll content, and electron transfer rate(P<0.05), while ginsenoside content was significantly negatively correlated with net photosynthetic rate, chlorophyll content, and electron transfer rate(P<0.05) and significantly positively correlated with AMF infestation rate and infestation intensity(P<0.05). In addition, ginsenoside content was significantly positively correlated with the activities of inter-root soil sucrase, urease, and catalase(P<0.05). This study provides basic data for revealing the mechanism of secondary metabolite accumulation in P. quinquefolius under understory planting and for exploring and practicing the ecological mode of P. quinquefolius under understory planting.
Panax/microbiology* ; China ; Secondary Metabolism ; Soil/chemistry* ; Photosynthesis ; Plant Leaves/metabolism* ; Chlorophyll/metabolism* ; Mycorrhizae

Based on copper death, this study investigates the effect and mechanism of Shenmai Injection on isoproterenol(ISO)-induced myocardial fibrosis(MF) in rats. SPF-grade male SD rats were randomly divided into a normal group, model group, captopril(5 mg·kg~(-1)) positive control group, and Shenmai Injection low(6 mL·kg~(-1)), medium(9 mL·kg~(-1)), and high(12 mL·kg~(-1)) dose groups. Except for the normal group, the rats in the other groups were subcutaneously injected with ISO(5 mg·kg~(-1)) once a day for 10 consecutive days to establish an MF model. Starting from the second day after successful modeling, intraperitoneal injections of the respective treatments were administered for 28 consecutive days. Hematoxylin-eosin(HE) and Masson staining were used to observe pathological changes and fibrosis levels in the myocardial tissue. Colorimetry was employed to detect serum Cu~(2+) concentration in rats. The levels of inflammatory cytokines interleukin-6(IL-6), interleukin-1β(IL-1β), interleukin-18(IL-18), tumor necrosis factor-α(TNF-α), as well as mitochondrial energy metabolites adenosine triphosphate(ATP), adenosine diphosphate(ADP), and adenosine monophosphate(AMP) in serum were measured using enzyme-linked immunosorbent assay(ELISA). Western blot was performed to detect the expression of collagen Ⅰ(Col-Ⅰ), collagen Ⅲ(Col-Ⅲ), and copper death-related proteins dihydrolipoamide acetyltransferase(DLAT), ferredoxin 1(FDX1), lipoic acid synthetase(LIAS), and heat shock protein 70(HSP70) in myocardial tissue. Immunofluorescence was used to detect the expression of DLAT, FDX1, and HSP70, while immunohistochemistry was conducted to examine the expressions of DLAT, FDX1, LIAS, and HSP70. The results showed that, compared to the model group, the myocardial structure disorder and collagen fiber deposition in the drug treatment groups were significantly improved, the cardiac index level was reduced, serum Cu~(2+), IL-6, IL-1β, IL-18, TNF-α, ADP, and AMP levels were significantly decreased, ATP levels were significantly increased, and the expressions of Col-Ⅰ, Col-Ⅲ, and HSP70 proteins in myocardial tissue were significantly reduced, while the expressions of DLAT, FDX1, and LIAS proteins were significantly elevated. In conclusion, Shenmai Injection effectively alleviates myocardial structure disorder and interstitial collagen fiber deposition in ISO-induced MF rats, promotes copper excretion, and reduces copper death in the ISO-induced rat MF model.
Animals ; Male ; Drugs, Chinese Herbal/administration & dosage* ; Rats, Sprague-Dawley ; Rats ; Myocardium/metabolism* ; Drug Combinations ; Fibrosis/metabolism* ; Copper/blood* ; Cardiomyopathies/genetics* ; Humans

The analysis presented here is based on the blood components of Guanxin Qiwei tablets, the key anti-atherosclerosis pathway of Guanxin Qiwei tablets was screened by network pharmacology, and the anti-atherosclerosis mechanism of Guanxin Qiwei tablets was clarified and verified by cell experiments. HPLC-Q-Exactive-MS/MS technique was used to analyze the components of Guanxin Qiwei tablets into blood, to determine the precise mass charge ratio of the compounds, and to conduct a comprehensive analysis of the components by using secondary mass spectrometry fragments and literature comparison. Finally, a total of 42 components of Guanxin Qiwei tablets into blood were identified. To better understand the interactions, we employed the Swiss Target Prediction database to predict the associated targets. Atherosclerosis (AS) disease targets were searched in disease databases Genecard, OMIM and Disgent, and 181 intersection targets of disease targets and component targets were obtained by Venny 2.1.0 software. Protein interactions were analyzed by String database. The 32 core targets were selected by Cytscape software. Gene Ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were performed in DAVID database. It was found that the anti-atherosclerosis pathways of Guanxin Qiwei tablets mainly include lipid metabolism and atherosclerosis and AGE-RAGE signaling pathway in diabetic complications and other signal pathways. The core targets and the core compounds were interlinked, and it was found that cryptotanshinone and tanshinone ⅡA in Guanxin Qiwei tablets were well bound to TNF, PPARγ, AKT1, PTG2 and other targets. The lipid metabolism and atherosclerotic pathway was verified using human hl-7702 hepatocytes. This study preliminarily identified the potential pharmacodynamic components of Guanxin Qiwei tablets in the treatment of AS diseases and predicted their pathways of action, and verified the relationship between regulating lipid metabolism and atherosclerosis of Guanxin Qiwei tablets in vitro, providing a reference for the further study of the pharmacodynamic material basis and mechanism of action of this prescription. This experiment was approved by the Medical Ethics Committee of Inner Mongolia Medical University (No. YKD202401262).