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.

Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by progressive cognitive decline, functional impairment, and neuropsychiatric symptoms. It represents the most prevalent form of dementia among the elderly population. Accumulating evidence indicates that oxidative stress plays a pivotal role in the pathogenesis of AD. Notably, elevated levels of oxidative stress have been observed in the brains of AD patients, where excessive reactive oxygen species (ROS) can cause extensive damage to lipids, proteins, and DNA, ultimately compromising neuronal structure and function. Amyloid β‑protein (Aβ) has been shown to induce mitochondrial dysfunction and calcium overload, thereby promoting the generation of ROS. This, in turn, exacerbates Aβ aggregation and enhances tau phosphorylation, leading to the formation of two pathological features of AD: extracellular Aβ plaque deposition and intracellular neurofibrillary tangles (NFTs). These events ultimately culminate in neuronal death, forming a vicious cycle. The interplay between oxidative stress and these pathological processes constitutes a core link in the pathogenesis of AD. The signaling pathways mediating oxidative stress in AD include Nrf2, RCAN1, PP2A, CREB, Notch1, NF‑κB, ApoE, and ferroptosis. Nrf2 signaling pathway serves as a key regulator of cellular redox homeostasis, exerts important antioxidant capacity and protective effects in AD. RCAN1 signaling pathway, as a calcineurin inhibitor, and modulates AD progression through multiple mechanisms. PP2A signaling pathway is involved in regulating tau phosphorylation and neuroinflammation processes. CREB signaling pathway contributes to neuroplasticity and memory formation; activation of CREB improves cognitive function and reduce oxidative stress. Notch1 signaling pathway regulates neuronal development and memory, participates in modulation of Aβ production, and interacts with Nrf2 toco-regulate antioxidant activity. NF‑κB signaling pathway governs immune and inflammatory responses; sustained activation of this pathway forms “inflammatory memory”, thereby exacerbating AD pathology. ApoE signaling pathway is associated with lipid metabolism; among its isoforms, ApoE-ε4 significantly increases the risk of AD, leading to elevated oxidative stress, abnormal lipid metabolism, and neuroinflammation. The ferroptosis signaling pathway is driven by iron-dependent lipid peroxidation, and the subsequent release of lipid peroxidation products and ROS exacerbate oxidative stress and neuronal damage. These interconnected pathways form a complex regulatory network that regulates the progression of AD through oxidative stress and related pathological cascades. In terms of therapeutic strategies targeting oxidative stress, among the drugs currently used in clinical practice for AD treatment, memantine and donepezil demonstrate significant therapeutic efficacy and can improve the level of oxidative stress in AD patients. Some compounds with antioxidant effects (such asα-lipoic acid and melatonin) have shown certain potential in AD treatment research and can be used as dietary supplements to ameliorate AD symptoms. In addition, non-drug interventions such as calorie restriction and exercise have been proven to exerted neuroprotective effects and have a positive effect on the treatment of AD. By comprehensively utilizing the therapeutic characteristics of different signaling pathways, it is expected that more comprehensive multi-target combination therapy regimens and combined nanomolecular delivery systems will be developed in the future to bypass the blood-brain barrier, providing more effective therapeutic strategies for AD.

Objective: To investigate the detection of depressive symptoms and its influencing factors among middle school students in Huzhou City, so as to provide insights for improving the mental health levels among middle school students. Methods: From September to November 2024, a total of 4 729 middle school students from five counties (districts) in Huzhou City were selected through the stratified cluster random sampling method. Demographic information, lifestyle, and school bullying were collected through questionnaire surveys. Depressive symptoms were assessed using the Center for Epidemiological Studies Depression Scale (CES-D). Factors affecting depressive symptoms among middle school students were analyzed using a multivariable logistic regression model. Results: A total of 4 729 middle school students were surveyed, including 2 200 boys (46.52%) and 2 529 girls (53.48%). Depressive symptoms were detected in 1 026 students, with a detection rate of 21.70%. Multivariable logistic regression analysis showed that girl (OR=1.960, 95%CI: 1.659-2.317), high school (ordinary high school, OR=1.789, 95%CI: 1.465-2.186; vocational high school, OR=1.581, 95%CI: 1.105-2.263), consumption of sugar-sweetened beverages >0 time/day (<1 time/day, OR=1.363, 95%CI: 1.009-1.841; ≥1 time/day, OR=1.568, 95%CI: 1.098-2.239), fried food intake ≥1 time/day (OR=1.890, 95%CI: 1.291-2.769), skipping breakfast daily (OR=2.178, 95%CI: 1.825-2.599), TV viewing time ≥2 hours/day (OR=1.457, 95%CI: 1.154-1.838), insufficient sleep duration (OR=1.761, 95%CI: 1.422-2.181), smoking (OR=2.798, 95%CI: 1.834-4.269), alcohol consumption (OR=2.282, 95%CI: 1.861-2.798), experiencing school bullying (OR=5.440, 95%CI: 3.148-9.402) and parental physical/verbal abuse (OR=3.954, 95%CI: 3.189-4.902) were associated with a higher risk of depressive symptoms among middle school students. Conversely, the middle school students who engaged in moderate-to-vigorous physical activity ≥3 times/week (OR=0.784, 95%CI: 0.668-0.921) and attended physical education classes ≥3 sessions/week (OR=0.736, 95%CI: 0.613-0.884) were associated with a lower risk of depressive symptoms. Conclusion The prevalence of depressive symptoms among middle school students in Huzhou City was lower than national average, and was influenced by dietary habits, physical exercise, sleep duration, smoking, alcohol consumption, and experiencing school bullying.

ObjectiveTo study the effect and mechanism of Yixintai on mitochondrial fission proteins in the rat model of chronic heart failure. MethodTen of 60 SD rats were randomly selected as the sham operation group， and the remaining 50 rats were subjected to ligation of the left anterior descending coronary artery for the modeling of heart failure post myocardial infarction. The successfully modeled rats were randomized into model， low-， medium-， and high-dose （1.4， 2.8， and 5.6 g·kg^-1， respectively） Yixintai， and trimetazidine （10 mg·kg^-1） groups. The rats were administrated with corresponding doses of drugs by gavage， and the rats in the model group and sham operation group were given an equal volume of normal saline by gavage for 28 consecutive days. Enzyme-linked immunosorbent assay （ELISA） was then employed to measure the levels of amino-terminal pro-B-type natriuretic peptide （NT-pro BNP）， B-type natriuretic peptide （BNP）， and adenosine triphosphate （ATP） in the serum. Color Doppler ultrasound imaging was conducted to examine the cardiac function indicators. Hematoxylin-eosin staining and Masson staining were conducted to observe the pathological changes in the heart， and Image J was used to calculate collagen volume fraction （CVF）. Transmission electron microscopy was employed to observe the ultrastructural changes of myocardial cells. Terminal-deoxynucleoitidyl transferase-mediated nick-end labeling （TUNEL） was employed to measure the apoptosis rate of myocardial cells. Western blot was employed to determine the protein levels of mitochondrial fission protein 1 （Fis1） and mitochondrial fission factor （Mff） in the outer mitochondrial membrane of the myocardial tissue. ResultCompared with the sham operation group， the model group showed elevated levels of NT-pro BNP and BNP in the serum， decreased ATP content， left ventricular ejection fraction （LVEF）， and left ventricular fraction shortening （LVFS）， increased left ventricular end-diastolic diameter （LVIDd） and left ventricular end-systolic diameter （LVIDs）， disarrangement of myocardial cells， inflammatory cell infiltration， increased collagen fibers and CVF， damaged myocardium and mitochondria， and increased apoptosis rate of myocardial cells， and up-regulated expression of Fis1 and Mff in the cardiac tissue （P<0.01）. Compared with the model group， different doses of Yixintai and trimetazidine lowered the serum levels of NT-pro BNP and BNP （P<0.05）， increased the ATP content （P<0.05）， increased LVEF and LVFS （P<0.01）， decreased LVIDd and LVIDs （P<0.01）. Moreover， the drugs alleviated the myocardial inflammatory damage and fibrosis， reduced CVF （P<0.01）， repaired the myocardial mitochondrial structure， and decreased the apoptosis rate of myocardial cells （P<0.01）. Medium- and high-dose Yixintai and trimetazidine down-regulated the expression of Fis1 and Mff in the myocardial tissue （P<0.05）. ConclusionYixintai can improve mitochondrial structure， reduce myocardial cell apoptosis， and improve cardiac function by inhibiting the expression of Fis1 and Mff in the myocardial tissue.

Four pyrazines were isolated from the n-butanol fraction of Hypecoum erectum L. by using various chromatographic methods, including MCI gel, ODS, silica gel and semi-preparative HPLC. The structures of the isolated compounds were identified as hyperectpyrazin A (1), 1′S-(6-methylpyrazin-2-yl)-ethane-1′,2′-diol (2), 2-hydroxymethyl-6-methylpyrazin (3) and pyrazine-2-carboxylic acid (4) by spectroscopy methods (1D NMR, 2D NMR, UV, IR, MS, etc.). The absolute configuration of compound 2 was determined by using the Mo₂(OAc)₄ induced CD analysis for the first time. Compound 1 was a new compound, compounds 2-4 were isolated from H. erectum for the first time. Compounds 1-4 were evaluated for their inhibition against acetylcholinesterase and nitric oxide generation induced by lipopolysaccharide-RAW264.7 macrophage cells. At a concentration of 50 μmol·L^-1, compounds 2 and 4 displayed inhibitory effects on acetylcholinesterase with the inhibition rates of 44.40% and 43.99%, respectively.

OBJECTIVE To analyze the chemical constituents and components absorbed into plasma of the extract of Ardisia crenata and to elucidate its possible pharmacodynamic material basis. METHODS Overall， 12 rats were randomly assigned to the blank group （n＝6） and A. crenata group （n＝6） by the paired comparison method. The drug was administered once daily in the morning and afternoon for three days. Serum samples were prepared from serum after redosing on 4th day. The UPLC-QE-HF-MS/ MS was used to analyze and identify the chemical constituents in A. crenata extract and serum samples. Compound Discoverer 3.0 was employed for retention time correction， peak identification， and peak extraction. According to the secondary mass spectrometry information， the Thermo mzCloud online and Thermo mzVault local databases， referring to the relevant literature and control quality spectrum information were used to preliminarily identify the chemical constituents and components absorbed into plasma of A. crenata. RESULTS A total of 34 compounds were identified from the extract of A. crenata， mainly coumarins， flavonoids， organic acids， amino acids， including bergenin， quercetin， gallic acid， L-pyroglutamic acid， etc. Besides， 5 components absorbed into plasma were identified from serum samples: L-pyroglutamic acid， syringic acid， bergenin， cinnabar root saponin A， and mycophenolic acid. CONCLUSIONS L-pyroglutamic acid， syringic acid， bergenin， cinnabar root saponin A， and mycophenolic acid may act as the pharmacodynamic material basis of A. crenata.

Objective To evaluate the effects of high-fat diet on the pharmacokinetics of metronidazole in Chinese healthy adult subjects.Methods This program is designed according to a single-center,randomized,open,single-dose trial.Forty-seven healthy subjects were assigned to receive single dose of metronidazole tablets 200 mg in either fasting and high-fat diet state,and blood samples were taken at different time points,respectively.The concentrations of metronidazole in plasma were determined by high performance liquid chromatography-mass spectromentry.Results The main pharmacokinetic parameters of metronidazole in fasting state and high-fat diet state were as follows:Cmax were(4 799.13±1 195.32)and(4 044.17±773.98)ng·mL-1;tmax were 1.00 and 2.25 h;t1/2 were(9.11±1.73)and(9.37±1.79)h;AUC0_t were(5.59±1.19)x 104 and(5.51±1.18)x 104 ng·mL-1·h;AUC0_∞ were(5.79±1.33)x 104 and(5.74±1.32)× 104 ng·mL-1·h.Compared to the fasting state,the tmaxof the drug taken after a high fat diet was delayed by 1.25 h(P＜0.01),Cmax,AUC0_t,AUC0-∞ were less or decreased in different degrees,but the effects were small(all P＞0.05).Conclusion High-fat diet has little effects on the pharmacokinetic parameters of metronidazole,which does not significantly change the degree of drug absorption,but can significantly delay the time to peak.

Objective To investigate the effects and mechanisms of lncRNA OIP5-AS1 on cell proliferation and apoptosis in esophageal squamous cell carcinoma(ESCC).Methods TE-1 cells were randomly divided into control(normal culture),si-NC(transfected with si-NC),si-OIP5-AS1(transfected with si-OIP5-AS1),si-OIP5-AS1+NC inhibitor(transfected with si-OIP5-AS1,NC inhibitor),si-OIP5-AS1+miR-129 inhibitor(transfected with si-OIP5-ASS1,miR-129 inhibitor),NC mimic(transfected with NC mimic),miR-129 mimic(transfected with miR-129 mimic),miR-129 mimic+Vector(transfected with miR-129 mimic,Vector),miR-129 mimic+KRAS[transfected with miR-129 mimic,Kirsten rat sarcoma virus oncogene(KRAS)]groups.The expression of OIP5-AS1 and miR-129 in each group was detected by real-time fluorescence quantitative polymerase chain reaction assay.The expression levels of KRAS,N-cadherin,Vimentin and E-cadherin in cells were detected by Western blot assay.Cell proliferation was detected by cell counting kit-8(CCK-8),and apoptosis was detected by terminal-deoxynucleoitidyl transferase mediated nick end labeling(TUNEL)assay.Results The expression levels of OIP5-AS1 in cells of control,si-NC,si-OIP5-AS1,si-OIP5-AS1+NC inhibitor,si-OIP5-AS1+miR-129 inhibitor groups were 1.00±0.13,0.98±0.12,0.25±0.04,0.25±0.02 and 0.89±0.08;the expression levels of miR-129 were 1.00±0.15,0.97±0.07,2.06±0.17,2.04±0.11 and 1.22±0.15;72 h absorbance values(OD)were 1.16±0.12,1.11±0.09,0.58±0.03,0.58±0.05 and 0.94±0.10.The KRAS protein expression levels of NC mimic,miR-129 mimic,miR-129 mimic+Vector,and miR-129 mimic+KRAS groups were 1.08±0.07,0.41±0.06,0.40±0.06,1.03±0.10;the 72 h OD values were 1.17±0.10,0.59±0.03,0.60±0.04 and 0.90±0.05,respectively.si-NC group was compared with si-OIP5-AS1 group,si-OIP5-AS1+NC inhibitor group was compared with si-OIP5-AS1+miR-129 inhibitor group,NC mimic group was compared with miR-129 mimic group,miR-129 mimic+Vector group was compared with miR-129 mimic+KRAS group,the differences of the above indexes were statistically significant(all P＜0.05).Conclusion OIP5-AS1 can promote ESCC cell proliferation and epithelial mesenchymal transformation by regulating miR-129 targeting KRAS.

Objective To investigate the effects of palmatine on migration,invasion and epithelial mesenchymal transformation(EMT)in human oral cancer KB cells.Methods KB cells were divided into control group and palmatine-L,-M,-H groups,cultured with 0,4,8 and 16 μmol·L-1 palmatine.After incubation for 48 h,scratch assay was used to detect migration;Traswell assay was used to detect invasion;matrix metalloproteinase 2(MMP-2),MMP-9 and fibronectin(FN)contents were detected by enzyme-linked immunosorbent assay;the expression of Vimentin,N-cadherin and E-cadherin mRNA were detected by real-time quantitative polymerase chain reaction;the expression of Vimentin,N-cadherin,E-cadherin,Wnt3 and β-catenin protein were detected by Western blot.Results Cell mobility in control group and palmatine-L,-M,-H groups were(69.27±8.62)％,(52.94±4.49)％,(45.22±5.05)％and(37.63±4.88)％;the number of transmembrane cells were 197.33±20.26,125.33±12.01,97.00±9.17 and 62.67±7.51;the content of MMP-2 were(2.93±0.21),(1.49±0.13),(1.16±0.15)and(0.95±0.09)ng·mL-1;the content of MMP-9 were(3.51±0.36),(2.37±0.23),(2.06±0.35)and(1.72±0.16)ng·mL-1;the content of FN were(41.28±4.02),(24.03±3.17),(20.67±2.63)and(13.82±2.19)ng·mL-1;the above indexes in palmatine-L,-M,-H groups were compared with the control group,and the differences were statistically significant(P＜0.05,P＜0.01).The mRNA and protein expressions of Vimentin,N-cadherin and E-cadherin,and the expressions of Wnt3 and β-catenin protein in palmatine-L,-M,-H groups were statistically significant compared with those in control group(P＜0.05,P＜0.01).Conclusion Palmatine can inhibit the migration,invasion and EMT of human oral cancer KB cells,and its mechanism is related to the regulation of Wnt/β-catenin signaling pathway.

Objective To investigate the feasibility and clinical experience of kidney transplantation from donors with Marfan syndrome (MFS). Methods Clinical data of 2 recipients undergoing kidney transplantation from the same MFS patient were retrospectively analyzed and literature review of 2 cases was conducted. Characteristics and clinical diagnosis and treatment of kidney transplantation from MFS patients were summarized. Results The Remuzzi scores of the left and right donor kidneys of the MFS patient during time-zero biopsy were 1 and 2. No significant difference was observed in the renal arteriole wall compared with other donors of brain death and cardiac death. Two recipients who received kidney transplantation from the MFS patient suffered from postoperative delayed graft function. After short-term hemodialysis, the graft function of the recipients received the left and right kidney began to gradually recover at postoperative 10 d and 20 d. After discharge, serum creatinine level of the recipient received the left kidney was ranged from 80 to 90 μmol/L, whereas that of the recipient received the right kidney kept declining, and the lowest serum creatinine level was 232 μmol/L before the submission date (at postoperative 43 d). Through literature review, two cases successfully undergoing kidney transplantation from the same MFS donor were reported. Both two recipients experienced delayed graft function, and then renal function was restored to normal. Until the publication date, 1 recipient has survived for 6 years, and the other recipient died of de novo cerebrovascular disease at postoperative 2 years. Conclusions MFS patients may serve as an acceptable source of kidney donors. However, the willingness and general conditions of the recipients should be carefully evaluated before kidney transplantation. Intraoperatively, potential risk of tear of renal arterial media should be properly treated. Extensive attention should be paid to the incidence of postoperative complications.