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 investigate the effects of ber-bamine on behavioral changes in LPS-induced chronic neuroinflammation model mice and the related mecha-nisms.Methods By injecting lipopolysaccharide in-traperitoneally for seven days in a row,berbamine was given intraperitoneally as a treatment;the behavioral studies of mice in each group were identified;Nissen staining was used to observe the changes in the patho-logical morphology of the mouse hippocampus and the expression levels of inflammation-related proteins.These procedures established a mouse neuroinflamma-tion model.Results The number of neurons in the model group's hippocampal CA1 and CA3 regions was significantly smaller than that in the control group.In the water maze experiment,as the number of training days grew,the model group's escape latency increased and its retention time in the target quadrant dropped.The immobilization period of the model group mice in-creased during the forced swimming exercise.Serum levels of inflammatory factors such as IL-1β,IL-6,and TNF-α levels were also higher.The hippocampus tis-sue of the mice in the model group had higher levels of NLRP3,ASC,caspase-1,IL-18,ROCK1,ROCK2 ex-pression,and RHOA.When compared to the model group,the administration of berbamine was a therapy intervention.In the meantime,with the number of training days increased,the target quadrant lag time increased and the escape latency gradually decreased.Additionally,the model group's mice spent less time resting during forced swimming,and the serum inflam-matory factors TNF-α,IL-1β,and IL-6 decreased in mouse hippocampal tissues.Lastly,the expression lev-els of NLRP3,caspase-1,ASC,IL-1β,ROCK1,ROCK2,and RHOA all decreased in mouse hippocam-pal tissue.Conclusions The mechanism of action of berbamine,which improves lipopolysaccharide-induced depressive-like behaviors and modifies learning memory in mice,may include the NLRP3 and RHOA/ROCK signaling pathways.

AIM To investigate the ameliorative effects of Schisandrol A(Sol A)in Suhuang antitussive capsule on post-infectious cough(PIC).METHODS The in vivo mouse PIC model was established by intratracheal instillation of lipopolysaccharide(LPS)combined with cigarette smoke exposure.The mice were randomly divided into the control group,the model group,the Suhuang antitussive capsule group(14 g/kg),the montelukast sodium positive control group(3 mg/kg),and low and high dose Sol A groups(10,30 mg/kg).The in vitro PIC model was established by stimulating human bronchial epithelial cells(BEAS-2B)with LPS.The cells were divided into the control group,the model group,the Suhuang antitussive capsule group(10 μg/mL)and low and high dose Sol A groups(3,10 μmol/L).HE and Masson staining were used to detect the pathological changes of the lung and bronchial tissues.ELISA was used to detect the levels of IL-1β,IL-6,TNF-α,ROS,MDA,SOD and GSH in the lung tissues.RT-qPCR was used to detect the IL-1β,IL-6 and TNF-α mRNA expressions in BEAS-2B cells.And Western blot was applied to detect the protein expressions of p-PI3K,p-Akt,NOX4,SIRT1,p-ERK,Fibronectin,E-cadherin,Vimentin and α-SMA in mouse lung tissue and BEAS-2B cells.RESULTS Compared with the model group,the groups intervened with Sol A or Suhuang antitussive capsule displayed prolonged cough latency(P＜0.01);reduced cough frequency(P＜0.01);relieved pulmonary inflammatory cell infiltration and collagen deposition in PIC mice;decreased pulmonary levels of IL-1β,IL-6,TNF-α,ROS,MDA and protein expressions of Fibronectin,Vimentin,α-SMA,p-ERK,p-PI3K,p-Akt,and NOX4(P＜0.05,P＜0.01);increased pulmonary levels of SOD and GSH and protein expressions of E-cadherin and SIRT1(P＜0.05,P＜0.01);decreased ROS level,IL-1β,IL-6,TNF-α mRNA expressions and p-ERK,p-PI3K,p-Akt,NOX4 protein expressions in vitro(P＜0.05,P＜0.01);and increased SIRT1 protein expression in vitro as well(P＜0.01).CONCLUSION Being the main antitussive component of Suhuang antitussive capsule upon the PIC model,Sol A inhibits the inflammation via SIRT1/ERK signaling pathway and relieve the oxidative stress via PI3K/Akt/NOX4 signaling pathway.

AIM To explore the effects of praeruptorin A from Suhuang antitussive capsules on cough variant asthma(CVA).METHODS The rats were randomly divided into the normal group,the model group,the dexamethasone group(0.5 mg/kg),the Suhuang antitussive capsules group(7 g/kg)and the low,medium and high dose praeruptorin A groups(15,30 and 60 mg/kg).The rat model of CVA was established by intraperitoneal injection of sensitizer(1 mg/mL ovalbumin and 10 mg/mL aluminum hydroxide)and aerosol inhalation of 1%ovalbumin followed by the corresponding dosing of drugs by gavage initiated on the 14th day.Another 14 days later,the rats had their pathological pulmonary changes observed by HE,Masson and PAS stainings;their number of inflammatory cells in bronchoalveolar lavage fluid(BALF)detected by hematology analyzer;and their levels of IL-4,IL-5,IL-13 and MUC5AC in BALF detected by ELISA.The RAW264.7 cell inflammatory model induced by lipopolysaccharide(LPS)was treated with 4,8,16 μmol/L praeruptorin A or 0.25 mg/mL Suhuang antitussive capsules,respectively.And the cells had their NO level detected by Griess method,and their ROS expression observed using fluorescence microscopy.The detections of the pulmonary and cellular mRNA expressions of IL-6,IL-1β,COX-2,iNOS and PPAR-γ by RT-qPCR;and the protein expressions of p-P65,P65,p-IκBα,IκBα,NLRP3,caspase-1(p20)and IL-1β by Western blot were conducted in both the cells and the rats.RESULTS The in vivo result showed that praeruptorin A reduced the cough frequency(P＜0.01);prolonged the cough latency(P＜0.05,P＜0.01);reduced the number of eosinophils and neutrophils in BALF(P＜0.05,P＜0.01);decreased the levels of IL-4,IL-5,IL-13 and MUC5AC in BALF and the pulmonary mRNA expressions of IL-6,IL-1β,COX-2 and iNOS(P＜0.05,P＜0.01);and decreased the phosphorylation of P65 and IκBα protein and NLRP3,caspase-1(p20)and IL-1β protein expressions(P＜0.05,P＜0.01)as well.The in vitro result showed that praeruptorin A inhibited the release of LPS-induced NO and reduce the ROS level(P＜0.01);decreased the mRNA expressions of IL-1β,COX-2 and iNOS(P＜0.05,P＜0.01);increased PPAR-γ mRNA expression(P＜0.05),and decreased the phosphorylation of P65 and IκBα protein and the expression of NLRP3 protein(P＜0.05,P＜0.01).CONCLUSION Praeruptorin A,one of the main antitussive components of Suhuang antitussive capsules,may improve CVA because of its anti-inflammatory and antitussive role by inhibiting the activation of NF-κB signaling pathway and reducing the expression of NLRP3 inflammatory corpuscles.

Objective: The aim of this study was to determine the poly (ADP-ribose) polymerase inhibitors (PARPis) response and outcome of ovarian cancer (OC) patients with BRCA1/2 germline mutation and a history of breast cancer (BC). Methods: Thirty-nine OC patients with BRCA1/2 germline mutation and a history of BC were included. The clinicopathological characteristics, PARPis response and prognosis were analyzed. Results: The median interval from BC to OC diagnosis was 115.3 months (range=6.4–310.1).A total of 38 patients (38/39, 97.4%) received platinum-based chemotherapy after surgical removal. The majority of these patients were reported to be platinum sensitive (92.1%, 35/38).21 patients (53.8%) received PARPis treatment with 16 patients (76.2%) for maintenance treatment and 5 patients (5/21, 23.8%) for salvage treatment. The median duration for PARPis maintenance and salvage treatment was 14.9 months (range=2.0–56.9) and 8.2 months (range=5.2–20.7), respectively. In the entire cohort, 5-year progression-free survival (PFS) and overall survival (OS) rate was 33.1% and 78.9%, respectively. Patients with BRCA1 mutation had a non-significantly worse 5-year PFS (28.6% vs. 45.8%, p=0.346) and 5-year OS (76.9% vs.83.3%, p=0.426) than those with BRCA2 mutation. In patients with stage III–IV (n=31), first line PARPis maintenance treatment associated with a non-significantly better PFS (median PFS: NR vs. 22.4 months; 5-year PFS: 64.3% vs. 21.9%, p=0.096). Conclusion The current study shows that these patients may have a good response to platinum-based chemotherapy and a favorable survival. And these patients can benefit from PARPis treatment and will likely be suitable candidates for PARPis.

Objective To understand the change in distribution and antimicrobial resistance of bacteria isolated from blood specimens of Hunan Province,and provide for the initial diagnosis and treatment of clinical bloodstream infection(BSI).Methods Data reported from member units of Hunan Province Antimicrobial Resistance Survei-llance System from 2012 to 2021 were collected.Bacterial antimicrobial resistance surveillance method was imple-mented according to the technical scheme of China Antimicrobial Resistance Surveillance System(CARSS).Bacteria from blood specimens and bacterial antimicrobial susceptibility testing results were analyzed by WHONET 5.6 soft-ware and SPSS 27.0 software.Results A total of 207 054 bacterial strains were isolated from blood specimens from member units in Hunan Province Antimicrobial Resistance Surveillance System from 2012 to 2021,including 107 135(51.7％)Gram-positive bacteria and 99 919(48.3％)Gram-negative bacteria.There was no change in the top 6 pathogenic bacteria from 2012 to 2021,with Escherichia coli(n=51 537,24.9％)ranking first,followed by Staphylococcus epidermidis(n=29 115,14.1％),Staphylococcus aureus(n=17 402,8.4％),Klebsiella pneu-moniae(17 325,8.4％),Pseudomonas aeruginosa(n=4 010,1.9％)and Acinetobacter baumannii(n=3 598,1.7％).The detection rate of methicillin-resistant Staphylococcus aureus(MRSA)decreased from 30.3％in 2015 to 20.7％in 2021,while the detection rate of methicillin-resistant coagulase-negative Staphylococcus(MRCNS)showed an upward trend year by year(57.9％-66.8％).No Staphylococcus was found to be resistant to vancomy-cin,linezolid,and teicoplanin.Among Gram-negative bacteria,constituent ratios of Escherichia coli and Klebsiella pneumoniae were 43.9％-53.9％and 14.2％-19.5％,respectively,both showing an upward trend(both P＜0.001).Constituent ratios of Pseudomonas aeruginosa and Acinetobacter baumannii were 3.6％-5.1％and 3.0％-4.5％,respectively,both showing a downward trend year by year(both P＜0.001).From 2012 to 2021,resistance rates of Escherichia coli to imipenem and ertapenem were 1.0％-2.0％and 0.6％-1.1％,respectively;presenting a downward trend(P＜0.001).The resistant rates of Klebsiella pneumoniae to meropenem and ertapenem were 7.4％-13.7％and 4.8％-6.4％,respectively,presenting a downward trend(both P＜0.001).The resistance rates of Pseudomonas aeruginosa and Acinetobacter baumannii to carbapenem antibiotics were 7.1％-15.6％and 34.7％-45.7％,respectively.The trend of resistance to carbapenem antibiotics was relatively stable,but has de-creased compared with 2012-2016.The resistance rates of Escherichia coli to the third-generation cephalosporins from 2012 to 2021 were 41.0％-65.4％,showing a downward trend year by year.Conclusion The constituent ra-tio of Gram-negative bacillus from blood specimens in Hunan Province has been increasing year by year,while the detection rate of carbapenem-resistant Gram-negative bacillus remained relatively stable in the past 5 years,and the detection rate of coagulase-negative Staphylococcus has shown a downward trend.

Objective To investigate changes in the distribution and antimicrobial resistance of bacteria isolated from cerebrospinal fluid(CSF)specimens in Hunan Province,and provide reference for correct clinical diagnosis and rational antimicrobial use.Methods Data reported by member units of Hunan Province Antimicrobial Resistance Surveillance System from 2012 to 2021 were collected according to China Antimicrobial Resistance Surveillance Sys-tem(CARSS)technical scheme.Data of bacteria isolated from CSF specimens and antimicrobial susceptibility tes-ting results were analyzed with WHONET 5.6 and SPSS 20.0 software.Results A total of 11 837 bacterial strains were isolated from CSF specimens from member units of Hunan Province Antimicrobial Resistance Surveillance Sys-tem from 2012 to 2021.The top 5 strains were coagulase-negative Staphylococcus(n=6 397,54.0％),Acineto-bacter baumannii(n=764,6.5％),Staphylococcus aureus(n=606,5.1％),Enterococcus faecium(n=465,3.9％),and Escherichia coli(n=447,3.8％).The detection rates of methicillin-resistant coagulase-negative Staphyloco-ccus(MRCNS)and methicillin-resistant Staphylococcus aureus(MRSA)were 58.9％-66.3％and 34.4％-62.1％,respectively.No Staphylococcus spp.were found to be resistant to vancomycin,linezolid,and teicoplanin.The de-tection rate of Enterococcus faecium was higher than that of Enterococcus faecalis,and the resistance rates of En-terococcus f aecium to penicillin,ampicillin,high concentration streptomycin and levofloxacin were all higher than those of Enterococcus faecalis(all P=0.001).Resistance rate of Streptococcus pneumoniae to penicillin was 85.0％,at a high level.Resistance rate of Escherichia coli to ceftriaxone was＞60％,while resistance rates to enzyme inhibitors and carbapenem antibiotics were low.Resistance rate of Klebsiella pneumoniae to ceftriaxone was＞60％,to en-zyme inhibitors piperacillin/tazobactam and cefoperazone/sulbactam was＞30％,to carbapenem imipenem and me-ropenem was about 30％.Resistance rates of Acinetobacter baumannii to most tested antimicrobial agents were＞60％,to imipenem and meropenem were 59.0％-79.4％,to polymyxin B was low.Conclusion Among the bac-teria isolated from CSF specimens,coagulase-negative Staphylococcus accounts for the largest proportion,and the overall resistance of pathogenic bacteria is relatively serious.Bacterial antimicrobial resistance surveillance is very important for the effective treatment of central nerve system infection.

Objective To investigate the distribution and antimicrobial susceptibility of clinically isolated bacteria from intensive care units(ICUs)in hospitals of Hunan Province Antimicrobial Resistance Surveillance System from 2012 to 2021.Methods According to China Antimicrobial Resistance Surveillance System,data of clinically isolated bacterial strains and antimicrobial susceptibility testing results of bacteria from ICUs reported by all member units of Hunan Province Antimicrobial Resistance Surveillance System were analyzed with WHONET 2022 software.Results From 2012 to 2021,the total number of bacteria isolated from ICUs of member units of the Hunan Province Antimi-crobial Resistance Surveillance System was 5 777-22 369,with Gram-negative bacteria accounting for 76.1％-78.0％annually.Staphylococcus aureus ranked first among isolated Gram-positive bacteria each year.The top 5 bacteria among Gram-negative bacteria were Acinetobacter baumannii,Klebsiella pneumoniae,Escherichia coli,Pseudo-monas aeruginosa,and Stenotrophomonas maltophilia.Detection rate of methicillin-resistant Staphylococcus aureus showed a downward trend year by year.No Staphylococcus spp.were found to be resistant to vancomycin,teico-planin and linezolid.Detection rates of vancomycin-resistant Enterococcus faecalis and vancomycin-resistant Entero-coccus faecium were 0.6-1.1％and 0.6％-2.2％,respectively.Resistance rates of Escherichia coli and Kleb-siella pneumoniae to imipenem were 3.1％-5.7％and 7.7％-20.9％,respectively.Resistance rates of Pseudo-monasaeruginosa and Acinetobacter baumannii to imipenem were 24.6％-40.1％and 76.1％-80.9％,respective-ly.Detection rates of carbapenem-resistant Pseudomonas aeruginosa declined year by year.Acinetobacter baumannii maintained high susceptibility to polymyxin B,with resistance rate＜10％.Conclusion Antimicrobial resistance of bacteria from ICUs is serious.Carbapenem-resistant Enterobacteriales has an upward trend after 2019.It is nece-ssary to strengthen the surveillance of bacterial resistance and carry out multidisciplinary collaboration.

Objective To understand the antimicrobial resistance of clinically isolated Enterococcus spp.in Hunan Province.Methods Surveillance data of Enterococcus spp.resistance from member units of Hunan Provincial Anti-microbial Resistance Surveillance System from 2012 to 2021 were collected.Data were cleaned according to a unified method,and WHONET 5.6 software was adopted for statistical analysis.Results From 2012 to 2021,a total of 110 652 non-repetitive Enterococcus spp.strains were included in the analysis,mainly Enterococcus faecalis and Enterococcus faecium,accounting for 46.9％(n=37 774)and 45.9％(n=36 968),respectively,followed by En-terococcus avium(2.5％,n=1 982),Enterococcus gallinarum(1.8％,n=1 428),and Enterococcus casseliflavus(1.5％,n=1 185).The main specimen sources of Enterococcus spp.was urine(51.8％,n=57 350),followed by secretions(9.6％,n=10 660)and bile(8.5％,n=9 377).From 2012 to 2021,the resistance rates of Enteroco-ccus faecalis to ampicillin,teicoplanin,and vancomycin were 5.5％-12.0％,1.3％-2.0％,and 0.6％-1.4％,respectively.The resistance rates of Enterococcus faecium to ampicillin,teicoplanin,and vancomycin were 69.2％-85.0％,1.5％-2.8％,and 0.7％-2.5％,respectively.Except for linezolid and minocycline,the resistance rates of Enterococcus faecium to tested antimicrobial agents were all higher than those of Enterococcus faecalis.The re-sistance rates of Enterococcus faecalis and Enterococcus faecium to vancomycin decreased from 1.4％and 2.1％in 2012 to 0.6％and 0.7％in 2021,respectively,presenting a decreased trend.Conclusion Clinically isolated En-terococcus spp.maintain high antimicrobial susceptibility to vancomycin and teicoplanin.Resistance rates of Entero-coccus faecalis and Enterococcus faecium to vancomycin present decreased trends.

Objective To analyze the distribution and changing trend of antimicrobial resistance of bacteria isolated from bile from Hunan Province Antimicrobial Resistance Surveillance System.Methods Data of pathogens isolated from bile from Hunan Province Antimicrobial Resistance Surveillance System from 2012 to 2021 were collected.The constituent of bacteria and antimicrobial susceptibility testing results were analyzed by WHONET 5.6 software.Changes in antimicrobial resistance was analyze by trend chi-square test.Results The major pathogenic bacteria isolated from bile were Gram-negative bacteria,accounting for 70.84％.The top three isolated Gram-negative pathogens were Escherichia coli(30.14％),Klebsiella pneumoniae(12.15％),and Pseudomonas aeruginosa(5.18％),and the top two Gram-positive bacteria were Enterococcus faecium(10.34％)and Enterococcus faecalis(9.52％).The resistance rates of Klebsiella pneumoniae and Escherichia coli to imipenem were highest in 2012-2013,being 15.7％and 14.9％,respectively,presenting an downward trend(P＜0.05);resistance rates to piperacillin/tazobactam and cefoperazone/sulbactam were＜24％,presenting an upward trend year by year(P＜0.05);the sus-ceptibility rate to amikacin was＞94％,to levofloxacin and ciprofloxacin was 15.5％-65.2％.The highest resis-tance rate of Pseudomonas aeruginosa to imipenem(32.0％)was higher than that of meropenem(22.9％),resis-tance rates to piperacillin/tazobactam and cefoperazone/sulbactam were＜19％.The highest resistance rates of Acinetobacter baumannii to imipenem and meropenem were 59.4％and 62.6％,respectively,resistance rate to cefo-perazone/sulbactam was＜48％,presenting an upward trend(P＜0.05);the highest resistance rate to ciprofloxa-cin(60.8％)was higher than levofloxacin(48.7％);resistance rate to tigecycline was＜8％.The resistance rates of Enterococcus faecium to penicillin and ampicillin were both higher than those of Enterococcus faecalis,presenting an upward trend(P＜0.05).Resistance rate of Enterococcus faecium to vancomycin was lower than that of Entero-coccus faecalis.The resistance rates of Enterococcus faecium to vancomycin and linezolid were 0.5％-4.5％and 0.5％-3.4％,respectively;resistance rates of Enterococcus faecalis to vancomycin and linezolid were 0.2％-1.7％and 0.5％-3.5％,respectively(both P＜0.05),all presenting a downward trend(all P＜0.05).Conclusion Pathogenic bacteria isolated from bile are mainly related to the intestinal flora.The resistance rates of Enterococcus faecalis and Enterococcus faecium to vancomycin and linezolid as well as resistance rate of Enterobacterales to car-bapenem antibiotics all present a downward trend.