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.

Aim To explore the improvement effect of Bazi Bushen capsule on thymic degeneration in SAMP6 mice and the possible mechanism.Methods Twenty 12 week old male SAMP6 mice were randomly divided into the model group(SAMP6)and the Bazi Busheng capsule treatment group(SAMP6+BZBS).Ten SAMR1 mice were assigned to a homologous control group(SAMR1).The SAMP6+BZBS group was oral-ly administered Bazi Bushen capsule suspension(2.8 g·kg-1)daily,while the other two groups were orally administered an equal amount of distilled water.After nine weeks of administration,the morphology of the thymus in each group was observed and the thymus in-dex was calculated;HE staining was used to observe the structural changes of thymus tissue;SA-β-gal stai-ning was used to detect thymic aging;flow cytometry was used to detect the proportion of thymic CD3+T cells in each group;Western blot was used to detect the levels of p16,Bax,Bcl-2,and cleaved caspase-3 proteins in thymus;immunofluorescence was applied to detect the proportion of cortical thymic epithelial cells in each group;ELISA was employed to detect IL-7 lev-els in thymus.Results Compared with the SAMP6 group,the thymic index of the SAMP6+BZBS group significantly increased(P＜0.05);the disordered thy-mic structure was significantly improved;the positive proportion of SA-β-gal staining significantly decreased(P＜0.01);the proportion of CD3+T cells apparently increased(P＜0.05);the level of p16 protein signifi-cantly decreased(P＜0.05);the level of Bcl-2 pro-tein significantly increased(P＜0.05),while the lev-el of cleaved caspase-3 protein markedly decreased(P＜0.05);the proportion of cortical thymic epithelial cells evidently increased;the level of IL-7 significantly increased(P＜0.01).Conclusions Bazi Bushen capsule can delay thymic degeneration,inhibit cell ap-optosis in thymus and promote thymic cell development in SAMP6 mice,which may be related to increasing the proportion of cortical thymic epithelial cells and promoting IL-7 secretion.

Child ; Humans ; Lead ; Urban Population ; Nutritional Status ; Health Surveys ; China/epidemiology* ; Rural Population

This study explored toxicity attenuation processing technology of Rhizoma Dioscoreae Bulbiferae stir-fried with Paeoniae Radix Alba decoction for the first time, and further explored its detoxification mechanism. Nine processed products of Rhizoma Dioscoreae Bulbiferae stir-fried with Paeoniae Radix Alba decoction were prepared by orthogonal experiment with three factors and three levels. Based on the decrease in the content of the main hepatotoxic component diosbulbin B before and after processing of Rhizoma Dioscoreae Bulbiferae by high-performance liquid chromatography, the toxicity attenuation technology was preliminarily screened out. On this basis, the raw and representative processed products of Rhizoma Dioscoreae Bulbiferae were given to mice by gavage with 2 g·kg~(-1)(equival to clinical equivalent dose) for 21 d. The serum and liver tissues were collected after the last administration for 24 h. The serum biochemical indexes reflecting liver function and liver histopathology were combined to further screen out and verify the proces-sing technology. Then, the lipid peroxidation and antioxidant indexes of liver tissue were detected by kit method, and the expressions of NADPH quinone oxidoreductase 1(NQO1) and glutamate-cysteine ligase(GCLM) in mice liver were detected by Western blot to further explore detoxification mechanism. The results showed that the processed products of Rhizoma Dioscoreae Bulbiferae stir-fried with Paeoniae Radix Alba decoction reduced the content of diosbulbin B and improved the liver injury induced by Rhizoma Dioscoreae Bul-biferae to varying degrees, and the processing technology of A_2B_2C_3 reduced the excessive levels of alanine transaminase(ALT) and aspartate transaminase(AST) induced by raw Rhizoma Dioscoreae Bulbiferae by 50.2% and 42.4%, respectively(P<0.01, P<0.01). The processed products of Rhizoma Dioscoreae Bulbiferae stir-fried with Paeoniae Radix Alba decoction reversed the decrease protein expression levels of NQO1 and GCLM in the liver of mice induced by raw Rhizoma Dioscoreae Bulbiferae to varying degrees(P<0.05 or P<0.01), and it also reversed the increasing level of malondialdehyde(MDA) and the decreasing levels of glutathione(GSH), glutathione peroxidase(GPX), and glutathione S-transferase(GST) in the liver of mice(P<0.05 or P<0.01). In summary, this study shows that the optimal toxicity attenuation processing technology of Rhizoma Dioscoreae Bulbiferae stir-fried with Paeoniae Radix Alba decoction is A_2B_2C_3, that is, 10% of Paeoniae Radix Alba decoction is used for moistening Rhizoma Dioscoreae Bulbiferae and processed at 130 ℃ for 11 min. The detoxification mechanism involves enhancing the expression levels of NQO1 and GCLM antio-xidant proteins and related antioxidant enzymes in the liver.
Mice ; Animals ; Antioxidants/analysis* ; Plant Extracts/pharmacology* ; Drugs, Chinese Herbal/chemistry* ; Rhizome/chemistry* ; Paeonia/chemistry* ; Glutathione/analysis*

Objective: The docking and superantigen activity sites of staphylococcal enterotoxin-like W (SElW) and T cell receptor (TCR) were predicted, and its SElW was cloned, expressed and purified. Methods: AlphaFold was used to predict the 3D structure of SElW protein monomers, and the protein models were evaluated with the help of the SAVES online server from ERRAT, Ramachandran plot, and Verify_3D. The ZDOCK server simulates the docking conformation of SElW and TCR, and the amino acid sequences of SElW and other serotype enterotoxins were aligned. The primers were designed to amplify selw, and the fragment was recombined into the pMD18-T vector and sequenced. Then recombinant plasmid pMD18-T was digested with BamHⅠand Hind Ⅲ. The target fragment was recombined into the expression plasmid pET-28a(+). After identification of the recombinant plasmid, the protein expression was induced by isopropyl-beta-D- thiogalactopyranoside. The SElW expressed in the supernatant was purified by affinity chromatography and quantified by the BCA method. Results: The predicted three-dimensional structure showed that the SElW protein was composed of two domains, the amino-terminal and the carboxy-terminal. The amino-terminal domain was composed of 3 α-helices and 6 β-sheets, and the carboxy-terminal domain included 2 α-helices and 7 antiparallel β-sheets composition. The overall quality factor score of the SElW protein model was 98.08, with 93.24% of the amino acids having a Verify_3D score ≥0.2 and no amino acids located in disallowed regions. The docking conformation with the highest score (1 521.328) was selected as the analysis object, and the 19 hydrogen bonds between the corresponding amino acid residues of SElW and TCR were analyzed by PyMOL. Combined with sequence alignment and the published data, this study predicted and found five important superantigen active sites, namely Y18, N19, W55, C88, and C98. The highly purified soluble recombinant protein SElW was obtained with cloning, expression, and protein purification. Conclusions: The study found five superantigen active sites in SElW protein that need special attention and successfully constructed and expressed the SElW protein, which laid the foundation for further exploration of the immune recognition mechanism of SElW.
Humans ; Enterotoxins/genetics* ; Superantigens/genetics* ; Catalytic Domain ; Selenoprotein W/metabolism* ; Receptors, Antigen, T-Cell

Emerging SARS-CoV-2 variants have made COVID-19 convalescents susceptible to re-infection and have raised concern about the efficacy of inactivated vaccination in neutralization against emerging variants and antigen-specific B cell response. To this end, a study on a long-term cohort of 208 participants who have recovered from COVID-19 was conducted, and the participants were followed up at 3.3 (Visit 1), 9.2 (Visit 2), and 18.5 (Visit 3) months after SARS-CoV-2 infection. They were classified into three groups (no-vaccination (n = 54), one-dose (n = 62), and two-dose (n = 92) groups) on the basis of the administration of inactivated vaccination. The neutralizing antibody (NAb) titers against the wild-type virus continued to decrease in the no-vaccination group, but they rose significantly in the one-dose and two-dose groups, with the highest NAb titers being observed in the two-dose group at Visit 3. The NAb titers against the Delta variant for the no-vaccination, one-dose, and two-dose groups decreased by 3.3, 1.9, and 2.3 folds relative to the wild-type virus, respectively, and those against the Omicron variant decreased by 7.0, 4.0, and 3.8 folds, respectively. Similarly, the responses of SARS-CoV-2 RBD-specific B cells and memory B cells were boosted by the second vaccine dose. Results showed that the convalescents benefited from the administration of the inactivated vaccine (one or two doses), which enhanced neutralization against highly mutated SARS-CoV-2 variants and memory B cell responses. Two doses of inactivated vaccine among COVID-19 convalescents are therefore recommended for the prevention of the COVID-19 pandemic, and vaccination guidelines and policies need to be updated.

AIM To analyze saponins from Panacis Quinquefolii Radix of different regions(Jilin,Liaoning,Heilongjiang,Shandong)based on UHPLC-Q-Orbitrap/MS technology.METHODS Panacis Quinquefolii Radix had its saponins qualitatively analyzed by UHPLC-Q-Orbitrap/MS;and its differential saponins revealing different regions screened by the principal component analysis,orthogonal partial least squares discriminant analysis and differential component analysis.RESULTS A total of 62 saponins were identified;saponin variations due to the growth areas verified by the principal component analysis;and 28 differential saponins including 13 protopanaxadiol,6 protopanaxatriol,4 oleanolane,2 oxytetracycline,and 3 C-17 side chain variants further screened by orthogonal partial least-squares discriminant analysis model.The relative contents of protopanaxadiol-type and protopanaxatriol-type saponins in the four producing areas reduced following the order of Liaoning,Jilin,Heilongjiang,and Shandong.CONCLUSION This simple,accurate and efficient method provides a theoretical basis for the quality evaluation of Panacis Quinquefolii Radix.

This study explored the protective effect of astragaloside Ⅳ(AS-Ⅳ) on oxygen-glucose deprivation(OGD)-induced autophagic injury in PC12 cells and its underlying mechanism. An OGD-induced autophagic injury model in vitro was established in PC12 cells. The cells were divided into a normal group, an OGD group, low-, medium-, and high-dose AS-Ⅳ groups, and a positive drug dexmedetomidine(DEX) group. Cell viability was measured using the MTT assay. Transmission electron microscopy was used to observe autophagosomes and autolysosomes, and the MDC staining method was used to assess the fluorescence intensity of autophagosomes. Western blot was conducted to determine the relative expression levels of functional proteins LC3-Ⅱ/LC3-Ⅰ, Beclin1, p-Akt/Akt, p-mTOR/mTOR, and HIF-1α. Compared with the normal group, the OGD group exhibited a significant decrease in cell viability(P<0.01), an increase in autophagosomes(P<0.01), enhanced fluorescence intensity of autophagosomes(P<0.01), up-regulated Beclin1, LC3-Ⅱ/LC3-Ⅰ, and HIF-1α(P<0.05 or P<0.01), and down-regulated p-Akt/Akt and p-mTOR/mTOR(P<0.05 or P<0.01). Compared with the OGD group, the low-and medium-dose AS-Ⅳ groups and the DEX group showed a significant increase in cell viability(P<0.01), decreased autophagosomes(P<0.01), weakened fluorescence intensity of autophagosomes(P<0.01), down-regulated Beclin1, LC3-Ⅱ/LC3-Ⅰ, and HIF-1α(P<0.05 or P<0.01), and up-regulated p-Akt/Akt and p-mTOR/mTOR(P<0.01). AS-Ⅳ at low and medium doses exerted a protective effect against OGD-induced autophagic injury in PC12 cells by activating the Akt/mTOR pathway, subsequently influencing HIF-1α. The high-dose AS-Ⅳ group did not show a statistically significant difference compared with the OGD group. This study provides a certain target reference for the prevention and treatment of OGD-induced cellular autophagic injury by AS-Ⅳ and accumulates laboratory data for the secondary development of Astragali Radix and AS-Ⅳ.
Rats ; Animals ; PC12 Cells ; Proto-Oncogene Proteins c-akt/genetics* ; Glucose/therapeutic use* ; Oxygen/metabolism* ; Beclin-1/pharmacology* ; TOR Serine-Threonine Kinases/metabolism* ; Autophagy ; Apoptosis ; Reperfusion Injury/drug therapy*

Carcinoma, Papillary/surgery* ; Humans ; Parapharyngeal Space ; Perivascular Epithelioid Cell Neoplasms ; Thyroid Cancer, Papillary ; Thyroid Neoplasms/surgery*

OBJECTIVE: To examine whether the combination of Naoxintong Capsule with standard care could further reduce the recurrence of ischemic stroke without increasing the risk of severe bleeding. METHODS: A total of 23 Chinese medical centers participated in this trial. Adult patients with a history of ischemic stroke were randomly assigned in a 1:1 ratio using a block design to receive either Naoxintong Capsule (1.2 g orally, twice a day) or placebo in addition to standard care. The primary endpoint was recurrence of ischemic stroke within 2 years. Secondary outcomes included myocardial infarction, death due to recurrent ischemic stroke, and all-cause mortality. The safety of drugs was monitored. Results were analyzed using the intention-to-treat principle. RESULTS: A total of 2,200 patients were enrolled from March 2015 to March 2016, of whom 143 and 158 in the Naoxintong and placebo groups were lost to follow-up, respectively. Compared with the placebo group, the recurrence rate of ischemic stroke within 2 years was significantly lower in the Naoxintong group [6.5% vs. 9.5%, hazard ratio (HR): 0.665, 95% confidence interval (CI): 0.492-0.899, P=0.008]. The two groups showed no significant differences in the secondary outcomes and safety, including rates of severe hemorrhage, cerebral hemorrhage and subarachnoid hemorrhage (P>0.05). CONCLUSION The combination of Naoxintong Capsule with standard care reduced the 2-year stroke recurrence rate in patients with ischemic stroke without increasing the risk of severe hemorrhage in high-risk patients. (Trial registration No. NCT02334969).
Adult ; Humans ; Secondary Prevention/methods* ; Ischemic Stroke ; Stroke/prevention & control* ; Cerebral Hemorrhage/complications* ; Double-Blind Method ; Platelet Aggregation Inhibitors