T7 RNA polymerase (T7 RNAP) is one of the simplest known RNA polymerases. Its unique structural features make it a critical model for studying the mechanisms of RNA synthesis. This review systematically examines the static crystal structure of T7 RNAP, beginning with an in-depth examination of its characteristic “thumb”, “palm”, and “finger” domains, which form the classic “right-hand-like” architecture. By detailing these structural elements, this review establishes a foundation for understanding the overall organization of T7 RNAP. This review systematically maps the functional roles of secondary structural elements and their subdomains in transcriptional catalysis, progressively elucidating the fundamental relationships between structure and function. Further, the intrinsic flexibility of T7 RNAP and its applications in research are also discussed. Additionally, the review presents the structural diagrams of the enzyme at different stages of the transcription process, and through these diagrams, it provides a detailed description of the complete transcription process of T7 RNAP. By integrating structural dynamics and kinetics analyses, the review constructs a comprehensive framework that bridges static structure to dynamic processes. Despite its advantages, T7 RNAP has a notable limitation: it generates double-stranded RNA (dsRNA) as a byproduct. The presence of dsRNA not only compromises the purity of mRNA products but also elicits nonspecific immune responses, which pose significant challenges for biotechnological and therapeutic applications. The review provides a detailed exploration of the mechanisms underlying dsRNA formation during T7 RNAP catalysis, reviews current strategies to mitigate this issue, and highlights recent progress in the field. A key focus is the semi-rational design of T7 RNAP mutants engineered to minimize dsRNA generation and enhance catalytic performance. Beyond its role in transcription, T7 RNAP exhibits rapid development and extensive application in fields, including gene editing, biosensing, and mRNA vaccines. This review systematically examines the structure-function relationships of T7 RNAP, elucidates the mechanisms of dsRNA formation, and discusses engineering strategies to optimize its performance. It further explores the engineering optimization and functional expansion of T7 RNAP. Furthermore, this review also addresses the pressing issues that currently need resolution, discusses the major challenges in the practical application of T7 RNAP, and provides an outlook on potential future research directions. In summary, this review provides a comprehensive analysis of T7 RNAP, ranging from its structural architecture to cutting-edge applications. We systematically examine: (1) the characteristic right-hand domains (thumb, palm, fingers) that define its minimalistic structure; (2) the structure-function relationships underlying transcriptional catalysis; and (3) the dynamic transitions during the complete transcription cycle. While highlighting T7 RNAP’s versatility in gene editing, biosensing, and mRNA vaccine production, we critically address its major limitation—dsRNA byproduct formation—and evaluate engineering solutions including semi-rationally designed mutants. By synthesizing current knowledge and identifying key challenges, this work aims to provide novel insights for the development and application of T7 RNAP and to foster further thought and progress in related fields.

Aim To explore the effects of Huannao Yicong decoction(HYD)on the learning and memory ability and brain iron metabolism in APP/PS1 mice and the correlation of HAMP knockout mice and APP/PS1 double transgenic model mice.Methods The ex-periment was divided into five groups,namely,HAMP-/-group(6-month HAMP gene knockout mice),APP/PS1 group(6-month APP/PS1-double-transgenic mice),HAMP-/-+HYD,APP/PS1+HYD,and negative control group(6-month C57BL/6J mice),with six mice in each group.The dose was ad-ministered(13.68 g·kg-1 weight),and the other groups received distilled water for gavage once a day for two months.After the administration of the drug,the mice in each group were tested for learning and memory in the Morris water maze;Biochemical detec-tion was performed to detect iron ion content in each mouse brain;Western blot and RT-qPCR were carried out to analyze hippocampal transferrin(TF),transfer-rin receptor1(TFR1),membrane iron transporter1(FPN1)divalent metal ion transporter 1(DMT1)and β-amyloid protein(Aβ)protein and mRNA expression levels in each group.Results Compared with the normal group,both HAMP-/-mice and APP/PS1 mice had reduced the learning and memory capacity,in-creased iron content in brain tissue,Aβ protein ex-pression increased in hippocampus of HAMP-/-group and APP/PS1 group mice(P＜0.01),the protein and mRNA expression of TF,TFR1 and DMT1 increased in hippocampal tissues of HAMP-/-and APP/PS1 groups(P＜0.01),and the FPN1 protein and mRNA expres-sion decreased(P＜0.01).Compared with the HAMP-and APP/PS1 groups,respectively,HAMP-/-+HYD group and APP/PS1+HYD group had improved learning and memory ability,decreased iron content,decreased Aβ protein expression(P＜0.01),decreased TF,TFR1,DMT1 protein and mR-NA expression(P＜0.01),and increased expression of FPN1 protein and mRNA(P＜0.01).Conclusions There is some association between HAMP-/-mice and APP/PS1 mice,HYD can improve the learning and memory ability of HAMP-/-and APP/PS1 mice and reduce the Aβ deposition.The mechanism may be related to the regulation of TF,TFR1,DMT1,FPN1 expression and improving brain iron overload.

This study was aimed at understanding the trends in,and scope of,severe fever with thrombocytopenia syndrome(SFTS)in Nanjing,analyzing the spatial distribution pattern,detecting high incidence cluster areas and key popula-tions,and scientifically guiding prevention and control strategies and measures.We obtained data on SFTS cases from 2010 to 2023 in Nanjing from the China Disease Control and Prevention Information System,and described the time,popu-lation,and spatial distribution characteristics.We used joinpoint regression to calculate the annual percentage change(APC)in incidence,then used FleXScan spatial clustering scan analysis to explore spatial clustering areas at the street level.A total of 507 SFTS cases were reported from 2010 to 2023 in Nanjing.The APC was 31.8％(95％CI:22.5％-41.9％,P＜0.001),and the reported incidence in 2023 was 1.42/100 000(134 cases).The seasonal indices from May to August were 2.7,2.1,3.0,and 1.3,respectively,accounting for 76.1％of the total cases.The median age was 66(IQR:55,73)years,which gradually increased from 59 years in 2010-2011 to 68 in 2022-2023(P＜0.001);94.1％of cases were in individuals 45 years or older.Farmers,homemakers/unemployed individuals,and retirees accounted for 90.1％.The epidemic area increased from 11 streets in four districts in 2010-2011 to 58 streets in 11 dis-tricts in 2022-2023.Except for 2012-2013,global spatial autocorrelation analysis showed positive Moran's I values(0.224-0.526,P＜0.001),and FlexScan scan indicated that several streets in Lishui District and Jiangning District were the most likely clusters.Four streets in Pukou District were the secondary clusters from 2018 to 2023,and three streets in Luhe District in 2022-2023 were the secondary clusters(all P＜0.05).The reported incidence of SFTS in Nanjing showed a rapid upward trend,with spread of epidemic areas.The spatial distribution pattern was clustered.Strengthened training in diagnosis and treatment technology and detection ability of medical institutions,surveillance in high-incidence areas,tracing of case flow,and health education of tick and disease prevention knowledge are recommended.

Objective To determine the effect of thrombus aspiration combined with intracoronary injection of recombinant human TNK tissue type plasminogen activator(rhTNK-tPA)on micro-circulation and cardiac function during primary PCI in elderly patients with acute myocardial in-farction(AMI).Methods A retrospective study was conducted on 90 elderly patients with STEMI undergoing primary PCI in Tianjin Third Central Hospital from January 2021 to October 2023.According to their treatment strategies,they were divided into simple suction group(n=46)and combination group(n=44).The suction group received a suction catheter for thrombus aspiration within the coronary artery,while the combined group got a suction catheter for thrombus aspira-tion within the infarct related blood vessels,and then received a local injection of rhTNK-tPA into the lesion through the suction catheter.Their general data,proportion of ST segment resolution(STR)≥70％at 90 min after surgery,postoperative TIMI blood flow grade,postoperative TIMI myocardial perfusion grade(TMPG),corrected TIMI frame count(CTFC)and cardiac ultrasound indicators as well as the incidence of adverse cardiac events during hospitalization were compared between the two groups.Results Larger proportions of postoperative STR ≥70％,postoperative TIMI blood flow grade 3 and TMPG grade 3,and lower CTFC were observed in the combination group than the suction group(P＜0.05).In 1 week after surgery,the simple suction group had lower left ventricular ejection fraction[LVEF,(52.5±6.2)％vs(58.3±6.4)％,P＜0.05],but larger left ventricular diameter(LVD,44.1±3.9 mm vs 51.9±2.5 mm,P＜0.05)than the com-bined group.The incidence of MACE during hospitalization was obviously lower in the combined group than the suction group(20.5％vs 37.0％,P＜0.05).Conclusion Combined intracoronary injection of rhTNK-tPA based on thrombotic aspiration can effectively reduce the coronary thrombus burden,improve myocardial microcirculation perfusion,reduce the incidence of MACE during hospitalization,and not increase the risk of bleeding in elderly STEMI patients.

Objective:To investigate the effects of Xiongcan Yishen Formula(XYF)on ferroptosis in mouse TM3 Leydig cells after oxidative stress injury(OSI)induced by H2O2.Methods:An oxidative stress injury model was established in mouse TM3 Leydig cells using H2O2 induction.The modeled TM3 cells were randomly divided into OSI group,XYF group,the ferroptosis inhibitor Ferrostatin-1(F-1)group,and F-1+XYF group,which were respectively intervened with blank serum,20%drug-containing serum,2μmol/L F-1,and2μmol/L F-1+20%drug-containing serum.A control group(normal TM3 cells+blank serum)was also set up.The morphology of cells in each group was observed,and the levels of testosterone,superoxide dismutase(SOD),reactive oxygen spe-cies(ROS),malondialdehyde(MDA),ferritin heavy chain 1(FTH1),solute carrier family 7 member 11(SLC7A11),glutathione(GSH),glutathione peroxidase 4(GPX4),fatty acid CoA ligase 4(FACL4),total iron ions,and ferrous ions were detected.Re-sults:Compared with the model group,the control group showed significantly decreased expression of ROS,MDA,FACL4,total iron,and ferrous ions(P<0.05),and significantly increased levels of testosterone,SOD,GSH,FTH1,SLC7A11,and GPX4(P<0.05).The male silkworm kidney-tonifying formula group significantly promoted testosterone secretion by TM3 cells and upregulated the expression of FTH1,SLC7A11,GPX4,GSH,and SOD in TM3 cells(P<0.05),while significantly downregulating ROS,MDA,FACL4,total iron ions,and ferrous ions(P<0.05).Conclusion:Following H2O2 exposure,oxidative stress can induce ferroptosis in mouse TM3 Leydig cells.XYF can antagonize OSI and ferroptosis in TM3 cells by activating the SLC7A11/GSH/GPX4 axis,which may underlie the mechanism of XYF in the treatment of male late-onset hypogonadism.

AIM To establish the HPLC fingerprints for freeze-dried powder of Yinhuo Decoction,and to determine the contents of rehmannitin D,methylophiopogonanone A,verbascoside,protocatechuic acid,catalpol,schisandrol A,schisandrin B,schisandrin A.METHODS The fingerprint esablishment was performed on a 30℃thermostatic Supersil AQ18 column(4.6 mm×250 mm,5 μm),with the mobile phase comprising of acetonitrile-0.1%phosphoric acid flowing at 1.0 mL/min in a gradient elution manner,and the detection wavelength was set at 230 nm.The UPLC-MS/MS content determination was performed on a 30℃thermostatic Alphasil VC-C18 column(2.1 mm×100 mm,2.5 μm),with the mobile phase comprising of acetonitrile-0.1%formic acid flowing at 0.3 mL/min in a gradient elution manner,and electron spray ionization source was adopted in positive and negative ion scanning with multiple reaction monitoring mode.RESULTS There were 17 common peaks in the fingerprints for 10 batches of freeze-dried powder with the similarities of more than 0.90.and piloside,crystal blue glycoside,deacetylated caryoside schisandrin A were identified.Eight constituents showed good linear relationships within their own ranges(R2＞0.990 6),whose average recoveries were 98.7%-101.1%with the RSDs of 2.0%-5.2%.CONCLUSION The combination of fingerprints and content determination can completely characterize the quality of Yinhuo Decoction reference sample,thus provide a reference for the quality evaluation of its key chemical properties.

AIM To establish a UPLC-MS/MS method for the simultaneous content determination of gallic acid,protocatechuic acid,neomangiferin,catechin,caffeic acid,mangiferin,isomangiferin,albiflorin,paeoniflorin,vitexin,liquiritin,scutellarin,baicalin,liquiritigenin,timosaponin BⅡ,quercetin,wogonoside,benzoylpaeoniflorin,isoliquiritigenin,honokiol,magnolol,norarecaidine,arecaidine,arecoline,epicatechin,baicalein,glycyrrhizinate and wogonin in Dayuan Drink.METHODS The analysis was performed on a 35℃thermostatic Syncronis C18 column(100 mm×2.1 mm,1.7 μm),with the mobile phase comprising of 0.1%formic acid-acetonitrile flowing at 0.3 mL/min in a gradient elution manner,and electron spray inoization source was adopted in positive and negative ion scanning with select reaction monitoring mode.RESULTS Twenty-eight constituents showed good linear relationships within their own ranges(R2≥0.991 0),whose average recoveries were 95.60%-103.53%with the RSDs of 0.60%-5.45%.CONCLUSION This rapid,simple,selective,accurate and reliable method can be used for the quality control of Dayuan Drink.

Objective To explore the mechanism of Buyang Huanwu Decoction for"treating different diseases with same therapies"in type 2 diabetes mellitus(T2DM)and Alzheimer's disease(AD)based on network pharmacology and molecular docking techniques.Methods Firstly,the active ingredients of seven herbs in Buyang Huanwu Decoction were searched and screened by TCMSP,SymMap and other databases,the target prediction of these active ingredients was carried out by PharmMapper.The disease targets of T2DM and AD were collected from OMIM,DrugBank,GeneCards and Disgenet databases.The potential targets of Buyang Huanwu Decoction for"treating different diseases with same therapies"in T2DM and AD were obtained by intersecting with targets of active ingredients and the disease targets.Then STRING database and Cytoscape software were used to construct the PPI network and"herbs-components-targets"network,respectively.The core targets and pharmacodynamic components were screened through network topology analysis.Furthermore,GO functional and KEGG enrichment analysis was performed for potential targets using Metascape database.Finally,AutoDock software was used to verify the molecular docking between the selected components and targets.Results Ninety-four active components of Buyang Huanwu Decoction can act on 342 protein targets,and 100 intersection targets were obtained by comparing with 3 140 AD targets and 1 708 T2DM targets.GO functional enrichment analysis showed that these targets were mainly involved in MAPK cascade-mediated regulation,hormone-mediated signaling pathways,cellular response to lipids,regulation of inflammation response and other biological processes.MAPK,PI3K/Akt,FoxO,AGE/RAGE,insulin resistance,lipid and atherosclerosis,and non-alcoholic fatty liver signaling pathway were significantly enriched in KEGG analysis.PPI and topology analysis of"herbs-components-targets"network were used to screen out 10 core targets such as MAPK8,MAPK14,GSK3B,PPARG,and 10 core pharmacodynamic components such as paeoniflorin,benzoyl paeoniflorin,(+)-catechin.The results of molecular docking showed that these components had strong binding ability to the targets.Conclusion The core components of Buyang Huanwu Decoction,such as paeoniflorin and catechin,may act on PPARG,GSK3B and other key targets,and participate in the regulation of signaling pathways including MAPK and PI3K/Akt,which play a role in"treating different diseases with the same therapies"of T2DM and AD.

Objective To observe the effects of melatonin on autophagy in cortical neurons of neonatal rats with hypoxic-ischemic brain damage(HIBD)and to explore its mechanisms via the PI3K/AKT signaling pathway,aiming to provide a basis for the clinical application of melatonin.Methods Seven-day-old Sprague-Dawley neonatal rats were randomly divided into a sham operation group,an HIBD group,and a melatonin group(n=9 each).The neonatal rat HIBD model was established using the classic Rice-Vannucci method.Neuronal morphology in the neonatal rat cerebral cortex was observed with hematoxylin-eosin staining and Nissl staining.Autophagy-related protein levels of microtubule-associated protein 1 light chain 3(LC3)and Beclin-1 were detected by immunofluorescence staining and Western blot analysis.Phosphorylated phosphoinositide 3-kinase(p-PI3K)and phosphorylated protein kinase B(p-AKT)protein expression levels were measured by immunohistochemistry and Western blot.The correlation between autophagy and the PI3K pathway in the melatonin group and the HIBD group was analyzed using Pearson correlation analysis.Results Twenty-four hours post-modeling,neurons in the sham operation group displayed normal size and orderly arrangement.In contrast,neurons in the HIBD group showed swelling and disorderly arrangement,while those in the melatonin group had relatively normal morphology and more orderly arrangement.Nissl bodies were normal in the sham operation group but distorted in the HIBD group;however,they remained relatively intact in the melatonin group.The average fluorescence intensity of LC3 and Beclin-1 was higher in the HIBD group compared to the sham operation group,but was reduced in the melatonin group compared to the HIBD group(P<0.05).The number of p-PI3K+and p-AKT+cells decreased in the HIBD group compared to the sham operation group but increased in the melatonin group compared to the HIBD group(P<0.05).LC3 and Beclin-1 protein expression levels were higher,and p-PI3K and p-AKT levels were lower in the HIBD group compared to the sham operation group(P<0.05);however,in the melatonin group,LC3 and Beclin-1 levels decreased,and p-PI3K and p-AKT increased compared to the HIBD group(P<0.05).The correlation analysis results showed that the difference of the mean fluorescence intensity of LC3 and Beclin-1 protein in the injured cerebral cortex between the melatonin and HIBD groups was negatively correlated with the difference of the number of p-PI3K+and p-AKT+cells between the two groups(P<0.05).Conclusions Melatonin can inhibit excessive autophagy in cortical neurons of neonatal rats with HIBD,thereby alleviating HIBD.This mechanism is associated with the PI3K/AKT pathway.

Patients with severe trauma require an extremely timely treatment and transfusion plays an irreplaceable role in the emergency treatment of such patients. An increasing number of evidence-based medicinal evidences and clinical practices suggest that patients with severe traumatic bleeding benefit from early transfusion of low-titer group O whole blood or hemostatic resuscitation with red blood cells, plasma and platelet of a balanced ratio. However, the current domestic mode of blood supply cannot fully meet the requirements of timely and effective blood transfusion for emergency treatment of patients with severe trauma in clinical practice. In order to solve the key problems in blood supply and blood transfusion strategies for emergency treatment of severe trauma, Branch of Clinical Transfusion Medicine of Chinese Medical Association, Group for Trauma Emergency Care and Multiple Injuries of Trauma Branch of Chinese Medical Association, Young Scholar Group of Disaster Medicine Branch of Chinese Medical Association organized domestic experts of blood transfusion medicine and trauma treatment to jointly formulate Chinese expert consensus on blood support mode and blood transfusion strategies for emergency treatment of severe trauma patients ( version 2024). Based on the evidence-based medical evidence and Delphi method of expert consultation and voting, 10 recommendations were put forward from two aspects of blood support mode and transfusion strategies, aiming to provide a reference for transfusion resuscitation in the emergency treatment of severe trauma and further improve the success rate of treatment of patients with severe trauma.