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.

Taxifolin (Tax) has been proved to be a medicinal edible substance with protective effects against alcoholic liver injury, however, its poor hydrophilicity and permeability have hindered the clinical application of Tax. In this study, we prepared taxifolin-phosphatidylcholine/sodium deoxycholate/PVP-K30 micells (Tax-MLs). Box-Behnken test was used to obtain the optimal preparation process, and Tax-MLs were characterised by transmission electron microscopy and fourier transform infrared spectroscopy. Physicochemical parameters such as proximate micelle concentration, equilibrium solubility and oil-water partition coefficient were determined, and the release pattern of Tax-MLs was investigated by in vitro digestion simulation. Alcoholic liver injury model to explore the in vivo efficacy of Tax-MLs. The results showed that the average particle size, polydispersity index (PDI) and zeta potential of Tax-MLs were 36.90 ± 4.57 nm, 0.194 ± 0.01 and -32.6 ± 0.35 mV, respectively, and the uniform size and distribution of Tax-MLs were observed by transmission electron microscopy. The formation of Tax-MLs was proved by differential scanning calorimetry and fourier transform infrared spectroscopy. In terms of physicochemical properties, the solubility of Tax-MLs in water increased by 92.02 times compared with Tax, and its oil-water partition coefficient in water increased from 0.43 to 1.14, which proved that Tax-MLs could improve its solubility and permeability. The in vivo pharmacodynamic results showed that compared with the Tax group, Tax-MLs low, medium and high dose groups showed a significant reduction in liver indices and serum levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) (P < 0.05), and enhanced the activities of superoxide dismutase (SOD) and glutathione (GSH), and lowered the levels of malondialdehyde (MDA) more significantly in the hepatic tissues. Tax-MLs effectively improved drug solubility and permeability, and enhanced the protective effect against alcoholic liver injury. Animal experiments were conducted with approval from the Animal Ethics Committee of Changchun University of Traditional Chinese Medicine (approval number: 2023601).

Objective To investigate the application value of quantitative parameters MRFDGmax and SUVmax in the stages of hepatitis,liver fibrosis and cirrhosis in rats by whole-body dynamic 18 F-FDG PET/CT Patlak imaging.Methods Twenty-four SD rats were randomly divided into four groups of six rats each,which were the normal group,hepatitis group,liver fibrosis group and cirrhosis group.According to the experimental grouping,rats in each group were induced by the CC14 oil solution complex method.Whole-body dynamic 18 F-FDG PET/CT patlak imaging was performed on each group of rats separately at the completion of induction.After the imaging was com-pleted,the MRFDGmax,SUVmax and CT values of the livers of each group were analyzed;subsequently,the serum of rats in each group was extracted for the detection of liver function indexes(AST,ALT and ALP),and HE staining was performed on the livers of rats in the normal,hepatitis and cirrhosis groups,and Masson staining was performed on those in the liver fibrosis group;the α-SMA expression in the liver tissues of each group was analyzed by immu-nohistochemical method.The data were analyzed by one-way ANOVA,two independent samples t-test and Pearson correlation analysis.Results MRFDGmax,SUVmax values were statistically significant differences among normal,hep-atitis,liver fibrosis and cirrhosis groups(F=84.54,38.35,P＜0.001).The difference in CT values between liver fibrosis and cirrhosis groups was not statistically significant(t=-0.407,P=0.693),and the difference was statistically significant when compared between the rest of the groups(F=112.25,P＜0.001).Compared with the normal group,AST,ALT and ALP of the experimental group showed a staged increase,and the differences were statistically significant(F=93.32,64.63,145.03,P＜0.001).HE staining showed that hepatocytes of the normal group were neatly arranged and structurally intact;a large number of inflammatory cells infiltrated the hepa-titis group with steatosis;pseudo lobe formation was observed in the cirrhosis group.Masson staining of the liver fi-brosis group showed collagen fiber proliferation and thickening of the peritoneum.Immunohistochemistry test results showed that α-SMA expression increased in hepatitis group,liver fibrosis group and cirrhosis group,with a staged increase,and the difference was statistically significant(F=80.57,P＜0.001).Correlation analysis showed a positive correlation between SUVmax and MRFDGmax(r=0.967,P＜0.01).α-SMA was positively correlated with AST,ALT and ALP in the hepatitis,liver fibrosis and cirrhosis groups,respectively(r=0.924,0.756,0.934,P＜0.01).Conclusion Whole-body dynamic 18F-FDG PET/CT Patlak imaging has application value in monitoring hepatitis,liver fibrosis and cirrhosis stages through quantitative parameters MRFDGmax and SUVmax changes.

Cellulose synthase (CesA), one of the key enzymes in the biosynthesis of cellulose in plants, plays an important role in plant growth and plant resistance. In this study, a total of 21 AsCesA genes from Aquilaria sinensis were systematically identified and the physico-chemical characteristics were analyzed based on genome database and bioinformatical methods. The phylogenetic tree was constructed and the gene location on chromosome, cis-acting elements in the 2 000 basepairs upstream regulatory regions and conservative motifs were analyzed. The AsCesA proteins were mainly located on the plasma membrane. The number of amino acids of the proteins ranged from 390 to 1 261. The isoelectric point distributed from 5.67 to 8.86. All of the 21 AsCesA proteins possessed the transmembrane domains, the number of which was from 6 to 8. The genes were classified into 3 groups according to the phylogenetic relationship. Obvious differences were observed in motif composition in genes from different groups. However, motif2, motif6, motif7 and motif10 were observed in all of AsCesA proteins. Analysis of cis-acting elements indicated that AsCesA genes family has cis-acting elements related to plant hormones, abiotic stresses, and biological processes. Seven AsCesA genes with differential expression were selected according to the calli transcriptome data induced by NaCl at different times and their expression levels under different abiotic stresses were analyzed by quantitative real-time PCR. The results indicated that salt, low temperature, drought, and heavy metal stresses could affect the expression level of AsCesA genes, and the abundance of AsCesA1, AsCesA3 and AsCesA20 showed a significant change, implying their potential important roles to the abiotic stresses. The accumulation pattern of cellulose content under different abiotic stresses was similar to the expression trend of AsCesA genes. Our results provide valuable insights into the role of cellulose synthase in A.sinensis in plant defense.

Platycodonis Radix is the dry root of Platycodon grandiflorum of Campanulaceae, which has a variety of pharmacological effects and is a commonly used bulk Chinese medicine. In this study, the chloroplast genome sequences of six P. grandiflorum from different producing areas has been sequenced with Illumina HiSeq X Ten platform. The specific DNA barcodes were screened, and the germplasm resources and genetic diversity were analyzed according to the specific barcodes. The total length of the chloroplast genome of 6 P. grandiflorum samples was 172 260-172 275 bp, and all chloroplast genomes showed a typical circular tetrad structure and encoded 141 genes. The comparative genomics analysis and results of amplification efficiency demonstrated that trnG-UCC and ndhG_ndhF were the potential specific DNA barcodes for identification the germplasm resources of P. grandiflorum. A total of 305 P. grandiflorum samples were collected from 15 production areas in 9 provinces, for which the fragments of trnG-UCC and ndhG_ndhF were amplificated and the sequences were analyzed. The results showed that trnG-UCC and ndhG_ndhF have 5 and 11 mutation sites, respectively, and 5 and 7 haplotypes were identified, respectively. The combined analysis of the two sequences formed 13 haplotypes (named Hap1-Hap13), and Hap4 is the main genotype, followed by Hap1. The unique haplotypes possessed by the three producing areas can be used as DNA molecular tags in this area to distinguish from the germplasm resources of P. grandiflorum from other areas. The haplotype diversity, nucleotide diversity and genetic distance were 0.94, 4.79×10^-3 and 0.000 0-0.020 3, respectively, suggesting that the genetic diversity was abundant and intraspecific kinship was relatively close. This study laid a foundation for the identification of P. grandiflorum, the protection and utilization of germplasm resources, and molecular breeding.

BACKGROUND:Studies have shown that posterior cruciate ligament injuries are associated with the anatomical morphology of the knee joint. OBJECTIVE:To explore anatomical morphological risk factors for posterior cruciate ligament injury. METHODS:The imaging data of 142 patients who visited Affiliated Hospital of Binzhou Medical University for knee joint problems from January 2015 to August 2022 were retrospectively analyzed.They were divided into posterior cruciate ligament injury group(n=71,including 49 males and 22 females)and posterior cruciate ligament intact group(n=71,including 49 males and 22 females).Intercondylar notch width,intercondylar notch height,bicondyle width,notch width index,angle of intercondylar notch,Blumensaat's line inlication angle,medial tibial spine height,lateral tibial spine height,tibial spine width,tibiofemoral consistency index,tibial plateau anterior-posterior diameter,medial tibial depth and patellar tendon-tibial shaft angle were measured on MRI images.Posterior tibial slope was measured on X-ray images.The above indicators were included in the logistic regression analysis for investigation. RESULTS AND CONCLUSION:(1)Univariate logistic regression analysis in men showed that tibial spine width,tibiofemoral consistency index,medial tibial depth,and posterior tibial slope were associated with posterior cruciate ligament injury(P<0.05).Multivariate binary logistic regression analysis showed that tibiofemoral consistency index and medial tibial depth were associated with posterior cruciate ligament damage(P<0.05).(2)Univariate logistic regression analysis in women showed that medial tibial spine height,lateral tibial spine height,tibial spine width,and posterior tibial slope were associated with posterior cruciate ligament injury(P<0.05).Multivariate binary logistic regression analysis showed that posterior tibial slope was associated with posterior cruciate ligament damage(P<0.05).(3)The receiver operating characteristic curve showed that tibiofemoral consistency index,medial tibial depth and posterior tibial slope had a certain predictive value on posterior cruciate ligament damage.(4)These findings suggest that anatomical morphological risk factors for posterior cruciate ligament injury differ between men and women,and tibial spine width and posterior tibial slope are common risk factors.In the male population,abnormal tibial spine width,tibiofemoral consistency index,medial tibial depth,and posterior tibial slope are easy to induce posterior cruciate ligament injury.In the female population,abnormal medial tibial spine height,lateral tibial spine height,tibial spine width,and posterior tibial slope are easy to induce posterior cruciate ligament injury.Clinicians can use the above risk factors to identify abnormal knee morphology,assess people at risk of posterior cruciate ligament injury,and provide preventive advice and guidance for treatment.

Acute liver injury (ALI) is one of the common severe diseases in clinic, which is characterized by redox imbalance and inflammatory storm. Untimely treatment can easily lead to liver failure and even death. Rosmarinic acid (RA) has been proved to have anti-inflammatory and antioxidant activity, but it is not clear how to protect ALI through antioxidation and inhibition of inflammation. Therefore, this study explored the therapeutic effect and molecular mechanism of RA on ALI through in vitro and in vivo experiments. In the mouse ALI model, the effects of RA on liver function and inflammatory indexes were studied, the pathological changes of liver were observed by HE, the effect of RA on reactive oxygen species in liver was detected by fluorescence method, and the level of F4/80 in liver tissue was detected by immunohistochemical method. The levels of thioredoxin interacting protein (TXNIP), NOD-like receptor protein 3 (NLRP3) and cysteinyl aspartate specific proteinase-1 (CASPASE-1) in liver tissue were measured by Western blot. All animal welfare and experimental procedures follow the rules of the Animal Ethics Committee of Southwest Minzu University. In vitro, human hepatoma cell line HepG2 was used to establish the model of oxidative damage induced by H₂O₂. The cell viability was detected by CCK-8 method. The level of interleukin-1β (IL-1β) in the supernatant was detected by enzyme linked immunosorbent assay (ELISA), the activity of lactatede hydrogenase (LDH) was detected by LDH kit, and the level of ROS was detected by fluorescence probe DCFH-DA labeling. The mRNA expression of Txnip, Nlrp3, Caspase 1, Il1β was detected by real-time fluorescence quantitative PCR (qPCR), and the protein levels of nuclear factor erythroid-2 related factor 2 (NRF2), TXNIP, NLRP3 and CASPASE-1 were measured by Western blot. The results showed that compared with the model group, the degree of liver swelling, tissue injury, liver function index in RA group were significantly lower than those in model group. And RA significantly attenuated the increases of ROS in liver tissue. The expression levels of TXNIP, NLRP3 and CASPASE-1 in liver tissue were significantly lower than those in model group. Additionally, RA inhibited the expressions of F4/80 and IL-1β. In vitro experiment, compared with model group, RA effectively inhibited the secretion of IL-1β and LDH. The level of ROS also decreased significantly. RA inhibited the mRNA expressions of Txnip, Caspase 1, Il1β. Furthermore, RA significantly increased the expression level of NRF2 protein in nucleus, and decreased the expression level of TXNIP and NLRP3 protein. Specifically, with the addition of ML385, the effect of RA on NRF2, TXNIP, NLRP3, CASPASE-1 protein expression was reversed. Collectively, these findings suggested that RA may inhibit the production of ROS by promoting NRF2 nuclear transfer, and then reduce the activation of NLRP3 inflammatory bodies by TXNIP, reduce cell death and inflammatory response to prevent the liver injury.

Three-dimensional ordered porous carbon materials exhibit potential application prospects as excellent drug supports in drug delivery systems due to their high specific surface area, tunable pore structure, and excellent biocompatibility. In this study, three-dimensional ordered porous carbon materials were prepared using Acanthopanax senticosus herbal residues as raw material and KOH as activating agent through a one-step pyrolysis method. The prepared carbon-based material was systematically characterized by powder X-ray diffraction, scanning electron microscopy, N₂ adsorption-desorption and Fourier-transform infrared spectroscopy. The results show that the three-dimensional ordered porous carbon materials prepared with KOH as the activator via pyrolysis possess abundant functional groups, high porosity, and high specific surface area, with a specific surface area of 1 471.6 m²·g^-1. The three-dimensional ordered porous carbon materials prepared at 800 ℃ exhibits a high drug loading capacity (78.0%) and drug release rate (86.8%) for 5-fluorouracil. Three-dimensional orderly porous carbon materials show significant application advantages in drug construction, and their high specific surface area and adjustable pore size structure significantly improve the drug load rate and drug release rate, providing a solid foundation for the development of efficient and accurate drug delivery system.

italic>Acanthopanax senticosus is one of the genuine regional herb in Northeast China. In this study, we identified the germplasm resources of commercial A. senticosus samples based on atpI and atpB_rbcL according to the previous chloroplast genome sequencing results, and determinated the content of syringin by HPLC to evaluated the quality of commercial samples. A total of 80 A. senticosus samples were collected from 47 cities in 24 provinces. DNA was extracted to amplify the products of atpI and atpB_rbcL by PCR. The results showed that 7 haplotypes (H2, H5, H8, H10, H12, H14, H23) were formed by the combined analysis of the two gene fragments. H2 from Yichun in Heilongjiang, Shangzhi in Harbin, Suihua in Heilongjiang, Fushun in Liaoning, Benxi in Liaoning, Changbai in Jilin and Jingyu in Jilin were the dominant genotype, representing 58.75% of the total samples. H14 and H23 were the unique haplotypes of the producing area. It is speculated that the commercial A. senticosus samples with haplotypes of H14 and H23 are from Raohe, Shuangyashan, Heilongjiang and Mingshui, Suihua, Heilongjiang, respectively. HPLC analysis indicated that the content of syringin in 73.96% of the samples met the Pharmacopoeia standards. There was a significant difference in the content of syringin among the samples, ranging from 0.003 7% to 0.524 5%, with a difference of 0.520 8%, indicating that the quality of the samples in the market of A. senticosus was uneven. However, there were no significant differences in the contents of syringin in the commercial A. senticosus among different haplotypes. The content of syringin in the haplotype H23 in the market sample is relatively high, so it may be a germplasm with better quality. This study researched the germplasm resources and medicinal materials quality of commercial A. senticosus samples and will help guide the commercial circulation, reasonable medication of A. senticosus, and the screening of excellent germplasm.

Brasilicardin A, a diterpene glycoside isolated from pathogenic actinomycete Nocardia brasiliensis IFM 0406, has become a novel immunosuppressant candidate due to its significant immunosuppressive activity, low toxicity and unique mechanism of action. However, brasilicardin A and its analogues have become a research hotspot to the development of this promising immunosuppressant because of the low-yield production in the natural pathogenic producer and the synthetically challenging skeleton. According to the reported biosynthetic pathway of brasilicardin A, the function of involved diterpene synthase was analyzed by bioinformatics. Then the genes bra1-5 that synthesize the brasilicardin A skeleton were directionally amplified from the pathogenic strain N. brasiliensis IFM 0406, and heterologous expression was achieved successfully in Streptomyces albus R1. The compounds were isolated and purified by using various column chromatographies including silica gel column chromatography and semi-preparative HPLC. Six new brasilicardins were established and named brasilicardin H-M. The activity of brasilicardins was screened using lipopolysaccharide (LPS)-activated mouse primary macrophage inflammation model. Brasilicardin H-M exhibited good inhibitory activity on nitric oxide (NO) release with IC₅₀ values of 28.24 ± 3.70, 37.44 ± 2.00, 39.85 ± 4.02, 26.77 ± 4.40, 65.25 ± 1.48 and 15.24 ± 2.72 μmol·L^-1, respectively (indomethacin as the positive control with IC₅₀ value of 34.28 ± 4.10 μmol·L^-1). The results indicated that six compounds had potential anti-inflammatory activity. This study laid a foundation for the elucidation of the brasilicardin A biosynthetic pathway and evaluation of the structure-activity relationship as well as new drug developments.