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.

Objective To explore the context and hotspot changes of forensic mixed stain research through bibliometric approach.Methods The literature of forensic mixed stain included in the core col-lection of Web of Science database from 2011 to 2022 were collected as the study object,and the an-nual publication number,countrie(region),institution,journal,keywords,etc.were bibliometrically and visually analyzed using the R-based Bibliometrix 1.1.6 package and VOSviewer 1.6.18 software.Re-sults A total of 732 articles on forensic mixed stain were included from 2011 to 2022,with the an-nual number of articles published and the annual citation frequency showing a steady increase year by year.Among the 59 countries(regions)with the most published articles,the United States ranked first with 246 articles,followed by China with 153 articles.The literature came from 104 journals,and the total number of articles published in the top 10 journals was 633.FORENSIC SCI INT GENET ranked first with 307 articles.Visual analysis using VOSviewer software showed that keywords could be divided into four research clusters,namely the genetic marker development group(blue),the mixed stain typing analysis theory group(red),the sequencing analysis group(yellow),and the case sample research group(green).It can be divided into four development stages in terms of different time peri-ods:early development(2011-2013),middle development(2014-2016),rapid development(2017-2020)and latest development(2021-2022).Conclusion The number of publications by domestic and foreign scholars in the study of mixed stain in forensic science is showing a relatively stable trend.Machine learning,next generation sequencing and other research have been the hottest topics that have attracted the most attention in recent years,which is expected to further develop the theory of mixed stain typing and sequencing analysis in forensic mixed stain research.

Objective To determine the acetylation level of nucleophosmin(NPM)in female breast cancer and to discuss its function through mutation of modified lysine sites.To construct positive and negative NPM mutants on its acetylated lysine sites and to express them in breast cancer cells.Methods Acetylation level and acetylated lysine sites of NPM in three breast cancer tissues and para-carcinoma tissues were detected by acetylome technology;NPM mutants were constructed by site-directed mutagenesis PCR,specific PCR products were digested by DpnI and transformed into Escherichia coli(E.coli)to obtain specific plasmids for mutants;The accuracy of mutants were verified by double restriction enzyme digestion and sequencing;The mutants were expressed in BT-549 cells by transient transfection and verified by RT-PCR method.Protein expression and acetylation level of NPM were validated by Western blotting;Function of NPM acetylation was analyzed by proteomic detection and bioinformatic analysis.Results The 27th and 32nd lysine of NPM were highly acetylated in breast cancer tissues,which were 2.76 and 2.22 times higher than those in adjacent normal tissues,respectively;The NPM mutants showed the same molecular weight as that of wild type NPM and contained expected mutation sites;Corresponding NPM mRNA levels of BT-549 cells transfected with NPM mutants were significantly increased.With the increase of wild type NPM expression level,NPM acetylation level increased,while decreased after 27th lysine underwent negative mutation.NPM acetylation can significantly change the expression levels of 101 proteins in BT-549 cells,which are enriched in regulation of cellular macromolecule biosynthesis,DNA-template transcription,RNA biosynthesis and RNA metabolism process.Conclusion NPM is highly acetylated in breast cancer and can play a key role in cellular macromolecule biosynthesis,DNA-templated transcription,RNA biosynthesis and RNA metabolism process.

Intraperitoneal administration of timosaponin A-III (TA-III) has therapeutic effects on high-fat diet-induced metabolic dysfunction-associated steatotic liver disease (MASLD), but oral administration has no effect. This suggests that gut microbiota may affect the oral bioavailability of TA-III. Metabolic dysfunction-associated steatohepatitis (MASH) is an inflammatory subtype of MASLD. To investigate the therapeutic effect of different administration modes of TA-III on MASH and its relationship with gut microbiota metabolism. In this study, a MASH mouse model was induced by choline-deficient, L-amino acid-defined, high-fat diet (CDAHFD). Comparing the therapeutic effect of intraperitoneal injection (10 mg·kg^-1, ip) and intragastric administration (100 mg·kg^-1, ig) of TA-III. The concentration of TA-III in serum of rats under the two administration modes was analyzed. On this basis, the metabolic effect of gut microbiota on TA-III in mice was verified by the experiment of metabolism of gut microbiota in vitro. The pharmacokinetic experiment of combined antibiotic intervention in mice further verified the metabolism of TA-III by gut microbiota in mice. Finally, the concentration of TA-III in serum of mice after the administration of TA-III by intragastric administration under different antibiotic intervention conditions was compared, and 16S rRNA sequencing analysis was combined to find the key bacteria that may participate in the metabolism of TA-III. The animal welfare and experimental procedures in this paper were in accordance with the provisions of the Animal Ethics Committee of Shanghai University of Traditional Chinese Medicine. The ethics approval number is PZSHUTCM2307030004 and PZSHUTCM2310200003. The results showed that TA-III (10 mg·kg^-1, ip) had definite therapeutic effect on MASH mice, but TA-III (100 mg·kg^-1, ig) was ineffective. The analysis showed that the prototype concentration of TA-III in serum and liver of mice in TA-III (100 mg·kg^-1, ig) was significantly lower than TA-III (10 mg·kg^-1, ip), suggesting that the oral administration of TA-III may be metabolized by gut microbiota. The concentration of TA-III in serum of streptomycin (Str) treated mice was higher than normal mice. Combined with 16S rRNA gene sequencing analysis, it was found that the abundance of Akkermansia_muciniphila (A. muciniphila) was significantly reduced in the Str group. In vitro experiments showed that A. muciniphila could metabolize TA-III. In conclusion, gut microbiota is an important factor affecting the efficacy of TA-III administration through the gastrointestinal tract, in which A. muciniphila may play an important role.

Objective To study the effect of Hedysarum polysaccharides(HPS)on the farnisol X receptor(FXR)-small heterodimer chaperone(SHP)-sterol regulatory element-binding protein 1 c(SREBP-1c)signaling pathway in the non-alcoholic fatty liver disease cell model.Methods The cells were cultured with 1.2 mmol·L-1 fatty acids to construct the non-alcoholic fatty liver disease cell model.The cell were divided into normal group(complete medium),model group(1.2 mmol·L-1 fatty acid solution),positive control group(1.2 mmol·L-1 fatty acid solution+50 μmol·L-1 alpha-lipoic acid)and experimental group(1.2 mmol·L-1 fatty acid solution+80 mg·L-1 HPS),culture for 24 h.The content of triglyceride(TG)and total cholesterol(TC),the activity of glutamate transaminase(GOT)and glutamate transaminasewas(GPT)detected by GPO-PAP enzyme method;the apoptosis rate was detected by flow cytometry;the expressions of FXR,SHP,SREBP-1c protein and mRNA in hepatocytes were detected by Western blot and reverse transcription-polymerase chain reaction(RT-PCR).Results The contents of TG in hepatocytes of normal group,model group,positve control group and experimental group were(2.91±1.13),(6.81±1.32),(3.72±0.52)and(4.67±0.62)mmol·gprot-1;the contents of TC in these four groups were(23.66±4.92),(67.96±5.56),(29.41±4.22)and(54.34±3.96)mmol·gprot-1;the activity of GOT in these four groups were(249.10±11.59),(322.63±28.81),(288.89±19.14)and(266.91±8.77)U·gprot-1;the activity of GPT in these four groups were(58.83±16.88),(134.55±22.96),(89.63±15.81)and(77.37±7.25)U·gprot-1,respectively;FXR mRNA expression levels were 1.01±0.16,2.09±0.12,1.83±0.17 and 1.45±0.15,respectively;SHP mRNA expression levels were 1.00±0.11,0.51±0.15,0.64±0.14 and 0.70±0.14,respectively;SREBP-1c mRNA were 1.00±0.08,1.57±0.19,1.37±0.13 and 1.21±0.15;the expression levels of FXR protein were 1.00±0.02,1.63±0.03,1.42±0.02 and 1.25±0.03,respectively;the expression levels of SHP protein were 1.00±0.02,0.23±0.01,0.54±0.21 and 0.62±0.02;the expression levels of SREBP-1c protein were 1.00±0.03,4.08±0.05,1.99±0.02 and 1.48±0.01,respectively.Compared with the normal group,there were significant differences in the above indexes of model group(all P＜0.05);compared with the model group,there were significant differences in the above indexes of experimental group(all P＜0.05).Conclusion HPS may protect liver cells by regulating the FXR-SHP-SREBP-1 c signaling pathway,reducing lipid synthesis in liver cells.

Objective To explore the relevant risk factors of H.pylori infection,and provide reference for prevention and treatment of H.pylori in this area,and further provide theoretical basis for the prevention and treatment of gastric cancer.Methods A total of 1200 residents in four districts of Haikou city were investigated by questionnaire and urea 14 C breath test by holistic stratified random sampling to calculate the population infection rate and analyze the risk factors of infection.Results The total infection rate was 32.5％,which was lower than the national H.pylori infection rate.No consumption of fruits and vegetables,no habit of washing hands before meals,and people with gastrointestinal symptoms,are independent risk factors of H.pylori infection.No consumption of pickled products is of great significance to prevent H.pylori infection.Conclusion The prevalence of H.pylori infection in the population of Haikou is lower than the national average,and H.pylori infection is closely related to the poor living habits of residents.

Three-dimensional graphene hydrogel(3DGH)was successfully prepared through a hydrothermal method,followed by its composition with gold nanoparticles(AuNPs)to construct a highly sensitive Au/3DGH graphene electrochemical transistor(GECT)dopamine(DA)sensor.AuNPs are efficient electrocatalytic materials.However,their tendency to aggregate during electrodeposition hinds the practical application.The porous and interconnected network structure of 3DGH provided abundant attachment sites,effectively preventing AuNPs aggregation.By modifying the sensor's gate with Au/3DGH,the excellent electrocatalytic performance of Au/3DGH towards DA and the high sensitivity of GECT were utilized to achieve highly sensitive detection of DA.The sensor exhibited a low detection limit of 20 nmol/L and a linear range of 20 nmol/L to 2.5 mmol/L.Remarkably,the sensor showed high sensitivity,excellent selectivity and strong stability,and hold great potnetial in highly sensitive portable detection of DA in disease prevention and clinical monitoring.

Ameloblastoma is a benign tumor characterized by locally invasive phenotypes,leading to facial bone destruction and a high recurrence rate.However,the mechanisms governing tumor initiation and recurrence are poorly understood.Here,we uncovered cellular landscapes and mechanisms that underlie tumor recurrence in ameloblastoma at single-cell resolution.Our results revealed that ameloblastoma exhibits five tumor subpopulations varying with respect to immune response(IR),bone remodeling(BR),tooth development(TD),epithelial development(ED),and cell cycle(CC)signatures.Of note,we found that CC ameloblastoma cells were endowed with stemness and contributed to tumor recurrence,which was dominated by the EZH2-mediated program.Targeting EZH2 effectively eliminated CC ameloblastoma cells and inhibited tumor growth in ameloblastoma patient-derived organoids.These data described the tumor subpopulation and clarified the identity,function,and regulatory mechanism of CC ameloblastoma cells,providing a potential therapeutic target for ameloblastoma.

Objective Little is known about the association between whole-blood nicotinamide adenine dinucleotide(NAD+)levels and nabothian cysts.This study aimed to assess the association between NAD+levels and nabothian cysts in healthy Chinese women. Methods Multivariate logistic regression analysis was performed to analyze the association between NAD+levels and nabothian cysts. Results The mean age was 43.0±11.5 years,and the mean level of NAD+was 31.3±5.3 μmol/L.Nabothian cysts occurred in 184(27.7%)participants,with single and multiple cysts in 100(15.0%)and 84(12.6%)participants,respectively.The total nabothian cyst prevalence gradually decreased from 37.4%to 21.6%from Q1 to Q4 of NAD+and the prevalence of single and multiple nabothian cysts also decreased across the NAD+quartiles.As compared with the highest NAD+quartile(≥34.4 μmol/L),the adjusted odds ratios with 95%confidence interval of the NAD+Q1 was 1.89(1.14-3.14)for total nabothian cysts.The risk of total and single nabothian cysts linearly decreased with increasing NAD+levels,while the risk of multiple nabothian cysts decreased more rapidly at NAD+levels of 28.0 to 35.0 μmol/L. Conclusion:Low NAD+levels were associated with an increased risk of total and multiple nabothian cysts.

Objective To investigate the effect of MALAT1 expressions on cell proliferation and apoptosis in astrocytes by regulating mitogen-activated protein kinase(MAPK)/extracellular signal-regulated kinase(ERK1,2)pathway.Methods The MALAT1 gene was knocked down and over-expressed in C8-D1A cells by lentiviral and plasmid vectors,respectively.The expressions of MALAT1,cell proliferation-related markers(Ki67,MCM2,PCNA)and apoptosis-related proteins(Caspase-3,Bax,Bcl-2)were detected by quantitative real-time polymerase chain reaction(qPCR).CCK-8 assay and flow cytometry were used for cell proliferation and apoptosis in C8-D1A cells.Immunofluorescence was adopted to detect the protein expressions of Caspase-3 and Ki67.Western blotting was used to detect the protein expressions of Caspase-3,Bax,Bcl-2,ERK1/2,p-ERK1/2,p38MAPK and p-p38MAPK.Results Compared with the control group,over-expressed MALAT1 inhibited cell proliferation and induced cell apoptosis in C8-D1A cells while the knockdown of MALAT1 significantly enhanced cell proliferation and anti-apoptotic ability in C8-D1A cells.The proportion of C8-D1A cells in G0/G1-phase and G2/M-phase was higher than in the control group as evidenced by flow cytometry,but was lower in S-phase.Meanwhile,data showed that Caspase-3 was increased while p-ERK1/2 was decreased in terms of protein levels.The mRNA expressions of Ki67 and PCNA were decreased.After knockdown of MALAT1,the proportion of C8-D1A cells in S-phase was higher,but was lower in G2/M-phase.The protein expressions of Caspase-3 and Bax decreased while those of p-ERK1/2 and p-p38MAPK increased.The mRNA expressions of Ki67,MCM2 and PCNA were increased.The differences were all statistically significant(P＜0.05).Conclusion MALAT1 promotes astrocyte apoptosis and inhibits proliferation by regulating the MAPK/ERK1,2 signaling pathway.