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 spatiotemporal expression patterns of Patched 1(Ptch1)and insulin enhancer binding protein-1(Isl 1)in mouse embryonic foregut and their relationship with the early development of trachea-main bronchus.Methods The foregut of 60 mouse embryos at E9.5-12.5 was separated for the detection of Isl1 and sonic hedgehog(Shh)protein by Western blotting.Serial paraffin sections of 6 mouse embryos at E9.5-14.5 were taken for immunohistochemical staining and immunofluorescence double staining with Isl1,Ptch1,forkhead box protein A2(Foxa2),type Ⅱ collagen α1 chain(Col2a1)and α-smooth muscle actin(α-SMA),as well as HE staining and Masson staining.Results The expression trend of Isl1 and Shh in foregut endoderm at E9.5-12.5 was similar,and the peak of Shh expression was later than Isl1.The foregut developed into the trachea at E9.5-12.5,Ptch1 was expressed in the thickening and protrusion of the respiratory endoderm,the laryngal-tracheal groove and the solid cell cord,accompanied by the increase and aggregation of Isl1-positive mesenchymal cells,forming a characteristic pyramidal structure centered on the respiratory endoderm and the solid cell cord;The main bronchus appeared at E12.5-13.5,Ptch1 was only expressed in its lateral wall,accompanied by the accumulation of Isl1-positive mesenchymal cells;The trachea-main bronchial epithelium lost Ptch1 expression and the surrounding Isl 1-positive mesenchymal cells also decreased rapidly at E13.5-14.5.Co12a1-positive chondrocytes first appeared in the Isl1-positive mesenchymal area adjacent to the Ptch1-positive epithelium at E12.5;Col2a1-positive cartilage was nested within the Isl1-positive mesenchymic area in a"C"shape and expanded in a proximal-distal pattern at E12.5-13.5;Col2a1-positive cartilage extended to the dorsal trachea beyond the Isl1-positive mesenchyma and encircles α-SMA positive smooth muscle in a circular manner at E14.5.Conclusion The expression of Ptch1 in the foregut endoderm is involved in the development and morphogenesis of the trachea-main bronchus epithelium,and is closely related to the proliferation and aggregation of Isl1-positive mesenchyme in the trachea-main bronchial wall,Subsequently,they jointly determine the time,location and extent of airway cartilage.

OBJECTIVE: Recent studies have overturned the traditional concept of the lung as a "sterile organ" revealing that pulmonary microbiota dysbiosis and abnormal surfactant proteins (SPs) expression are involved in the progression of silicosis. This study aimed to investigate the relationship between abnormal SPs expression and dysbiosis of lung microbiota in silica-induced lung fibrosis, providing insights into mechanisms of silicosis. METHODS: Lung pathology, SPs expression, and microbiota composition were evaluated in silica-exposed mice. A mouse model of antibiotic-induced microbiota depletion was established, and alveolar structure and SPs expression were assessed. The roles of the lung microbiota and SPs in silicosis progression were further evaluated in mice with antibiotic-induced microbiota depletion, both with and without silica exposure. RESULTS: Silica exposure induced lung inflammation and fibrosis, along with increased expression of SP-A expression. Antibiotics (Abx)-induced microbiota depletion elevated SP-A and SP-D expression. Furthermore, silica exposure altered lung microbiota composition, enriching potentially pathogenic taxa. However, antibiotic-induced microbiota depletion prior to silica exposure reduced silica-mediated lung fibrosis and inflammation. CONCLUSION Lung microbiota is associated with silica-induced lung injury. Overproduction of SP-A and SP-D, induced by Abx-induced microbiota depletion, may enhance the resistance of mouse lung tissue to silica-induced injury.
Animals ; Silicosis/prevention & control* ; Lung/metabolism* ; Mice ; Anti-Bacterial Agents/pharmacology* ; Microbiota/drug effects* ; Silicon Dioxide/toxicity* ; Mice, Inbred C57BL ; Male ; Pulmonary Surfactant-Associated Proteins/genetics*

Spine fracture and dislocation are common traumatic spinal conditions that often require surgical intervention due to compromised spinal stability. Surgical approaches include anterior, posterior, and combined anterior-posterior spinal procedures. According to the specific surgical requirements, patients may be placed in the prone position or repositioned between prone and supine positions during surgery. Intraoperative repositioning has become an essential step in patient positioning. However, during repositioning, patients with spinal fracture and dislocation are at increased risk for complications such as hemodynamic instability, nerve injury, and pressure injuries to the skin and soft tissue. Notably, due to the instability of the spinal cord, even minor manipulations can further exacerbate the damage, potentially leading to severe outcomes like paraplegia. Although the current clinical guidelines provide instructive recommendations for standard position, there remains no specific protocols for intraoperative repositioning in patients with spine fracture and dislocation. With a concern for the lack of clinical studies on positioning techniques, risk prevention, and operational norms for special patients, no applicable guidelines or standards are available. A consensus was required to provide clinical reference, meet the requirements of surgical treatment, and minimize the safety risks of patients caused by improper placement of positions. Professional Committee of Operating Room Nursing of Shaanxi Nursing Association organized experts in nursing management and operating room nursing from major hospitals across China to formulate Expert consensus on intraoperative repositioning for patients with spinal fracture and dislocation ( version 2025). The consensus provides 11 recommendations covering pre-repositioning preparation, intraoperative maneuvers, and post-repositioning observation, aiming to provide references for clinical standardization of the intraoperative repositioning process and protection of patients′ safety.

AIM To compare the chemical constituents in traditional decoction and formula granule decoction of classical famous prescription Wendan Decoction.METHODS The HPLC fingerprints were established,after which the contents of adenosine,synephrine,liquiritin,naringin,hesperidin,6-gingerol and adenosine cyclophosphate were determined,cluster analysis,principal component analysis and multidimensional scaling analysis were adopted in the investigation of component differences,and the equivalent of formula granules was adjusted.RESULTS The similarities of HPLC fingerprints for 10 batches of traditional decoctions were higher than those of HPLC fingerprints for 9 batches of formula granule decoctions(P＜0.01).Adenosine,synephrine,liquiritin,hesperidin and cyclic adenosine monophosphate demonstrated higher contents in traditional decoctions than those in formula granule decoctions(P＜0.05),6-gingerol displayed lower content than that in the latter produced by manufacturers A,C(P＜0.05),which was higher than that in the latter produced by manufacturer B(P＜0.01).Various batches of traditional decoctions and formula granule decoctions could be obviously distinguished,adenosine,synephrine and hesperidin exhibited great influences on the classification of principal component analysis,and the quality of formula granule decoctions produced by manufacturer C was closer to that of traditional decoctions.After equivalent correction,the contents of various constituents in formula granule decoctions produced by manufacturers A,C showed no significant differences as compared with those in traditional decoction(P＞0.05).CONCLUSION The formula granules of Wendan Decoction from different manufacturers exist quality differences,so the preparation process and extraction process of this preparation should be optimized to improve quality,and equivalent ratio should be adjusted according to actual requirements to ensure its scientific and rational clinical application.

Objective To explore the characteristics of fluid flow within loaded osteons under different boundary conditions.Methods The COMSOL Multiphysics software was used to establish a three-dimensional(3D)finite element model of osteons with different boundary conditions,and the variation rules of pore pressure and flow velocity of osteons under different inner wall pulsating blood pressures and outer wall elastic constraint conditions were analyzed.Results As the pulsatile blood pressure inside the osteon increased from 0 mmHg(1 mmHg=0.133 kPa)to 300 mmHg,the peak pore pressure within the osteon correspondingly increased from 26 kPa to 68 kPa.As the elastic constraint on the outer wall of osteons changed from being completely elastic to completely constrained,the peak pore pressure within osteons increased from 15 kPa to 26 kPa,and the peak flow velocity increased from 0.04 um/s to 0.07 um/s.Conclusions This study reveals the influence laws of changes in boundary conditions such as the pulsatile blood pressure on the inner wall and the elastic constraint on the outer wall of osteons on fluid flow characteristics within loaded osteons.These findings are conducive to a deeper understanding of the mechanical response mechanisms of bone tissues in both physiological and pathological states,and provide an important theoretical basrs for further researches on bone mechanotransduction.

Objective:To explore the value of fetal heart quantification technology in assessing the morphology and function of the fetal heart during normal pregnancy.Methods:This prospective cohort study selected normal fetuses from healthy pregnant women who underwent prenatal ultrasound examinations at Hunan Provincial People's Hospital from January 2023 to October 2024. Using the GE Voluson E10 color Doppler diasonography, routine obstetric ultrasound and fetal echocardiography were performed to assess fetal growth and development and to exclude intracardiac and extracardiac malformations. Clear four-chamber view (4CV) dynamic images of the heart showing the endocardium (duration ≥3 s) were collected. Speckle-tracking analysis was performed using fetal heart quantification software. The measured indicators included the global spherical index (GSI), end-diastolic length of the heart (L-ED), end-diastolic width of the heart (W-ED), and the global longitudinal strain (GLS), fractional area change (FAC), and 24-segment spherical index (SI) of the left ventricle (LV) and right ventricle (RV). The cases were divided into five groups based on gestational age at the time of prenatal ultrasound: 20 +0 to 23 +6, 24 +0 to 27 +6, 28 +0 to 31 +6, 32 +0 to 35 +6, and 36 +0 to 40 +6 weeks. One-way analysis of variance, two independent samples t-test, univariate linear regression analysis, and Pearson correlation analysis were used to explore the differences in the above indicators among different gestational age groups and their correlation with gestational age. Results:A total of 200 pregnant women were included in the cohort, four cases were excluded due to poor image quality that prevented accurate tracking and measurement of relevant indicators. Ultimately, 196 cases (20 +0 to 23 +6 weeks 40 cases, 24 +0 to 27 +6 weeks 34 cases, 28 +0 to 31 +6 weeks 41 cases, 32 +0 to 35 +6 weeks 48 cases, and 36 +0 to 40 +6 weeks 33 cases) were included in the study, with a successful image analysis rate of 98.0%. (1) There were statistically significant differences in 4CV L-ED, 4CV W-ED, LV-FAC, and RV-FAC among the groups at 20 +0 to 23 +6, 24 +0 to 27 +6, 28 +0 to 31 +6, 32 +0 to 35 +6, and 36 +0 to 40 +6 weeks [4CV L-ED: 28.0±3.0, 32.6±4.3, 40.9±4.3, 46.7±4.8, 53.1±5.8, F=3.72; 4CV W-ED: 21.9±1.8, 25.1±4.2, 31.7±3.0, 37.4±4.0, 42.0±4.9, F=2.61; LV-FAC: (51.4±8.0)%, (49.0±10.4)%, (47.3±7.3)%, (43.1±7.5)%, (40.7±8.2)%, F=2.94; RV-FAC: (49.9±10.8)%, (46.2±12.0)%, (46.3±8.3)%, (43.2±8.0)%, (41.9±5.6)%, F=3.09; all P<0.05].(2) The size of the normal fetal heart gradually increased with gestational age, while the heart morphology remained relatively stable (4CV L-ED and 4CV W-ED were positively correlated with gestational age, with regression coefficients of 1.313 and 1.325, respectively, both P<0.001;LV-FAC and RV-FAC were negatively correlated with gestational age with regression coefficients of -0.783 and -0.552, respectively, both P<0.001; GSI, LV-GLS and RV-GLS had no correlations with gestational age, all P>0.05). (3) The SI of LV segments 1 to 17 were higher than the SI of the corresponding RV segments, and the SI of RV segments 20-24 were higher than that of the corresponding LV segments (all P<0.001). Conclusion:Fetal heart quantification technology has a certain value in the assessment of fetal cardiac morphology and function.

AIM To compare the chemical constituents in traditional decoction and formula granule decoction of classical famous prescription Wendan Decoction.METHODS The HPLC fingerprints were established,after which the contents of adenosine,synephrine,liquiritin,naringin,hesperidin,6-gingerol and adenosine cyclophosphate were determined,cluster analysis,principal component analysis and multidimensional scaling analysis were adopted in the investigation of component differences,and the equivalent of formula granules was adjusted.RESULTS The similarities of HPLC fingerprints for 10 batches of traditional decoctions were higher than those of HPLC fingerprints for 9 batches of formula granule decoctions(P＜0.01).Adenosine,synephrine,liquiritin,hesperidin and cyclic adenosine monophosphate demonstrated higher contents in traditional decoctions than those in formula granule decoctions(P＜0.05),6-gingerol displayed lower content than that in the latter produced by manufacturers A,C(P＜0.05),which was higher than that in the latter produced by manufacturer B(P＜0.01).Various batches of traditional decoctions and formula granule decoctions could be obviously distinguished,adenosine,synephrine and hesperidin exhibited great influences on the classification of principal component analysis,and the quality of formula granule decoctions produced by manufacturer C was closer to that of traditional decoctions.After equivalent correction,the contents of various constituents in formula granule decoctions produced by manufacturers A,C showed no significant differences as compared with those in traditional decoction(P＞0.05).CONCLUSION The formula granules of Wendan Decoction from different manufacturers exist quality differences,so the preparation process and extraction process of this preparation should be optimized to improve quality,and equivalent ratio should be adjusted according to actual requirements to ensure its scientific and rational clinical application.

Aim To study the protective effect of the silibinin derivative Sil-1 on acute myocardial ischemia in SD rats and its mechanism of action.Methods Af-ter 18 hours of oxygen-glucose deprivation and treat-ment of H9c2 cells,the protective effect of Sil-1 on rat cardiomyocytes was examined.SD rats were treated 30 minutes before surgery,followed by 24 h ligation of the left anterior descending coronary artery.The cardiopro-tective effects of Sil-1 and its mechanisms for improving myocardial ischemic injury were investigated using pro-teomics technology.Results In vitro,compared with the control group,the activity of H9c2 cells in the mod-el group showed reduced cell viability,increased dead cells,elevated ROS and higher levels of LDH and in-flammatory cytokines TNF-α,IL-1β and IL-6 in the culture medium.Sil-1 could improve the above condi-tions to different degrees.In vivo,compared with the control group,rats in the model group showed signifi-cantly higher T waves on electrocardiogram,significant ischemic areas in the heart section,disorganized ar-rangement of cardiomyocytes,increased inflammatory factor infiltration and elevated CK,CK-MB,LDH and inflammatory factors TNF-α,IL-6 and IL-1β.Besides,NF-κB phosphorylation levels in myocardial tissue in-creased.Sil-1 improved the above conditions to varying degrees.The results of proteomics showed that 90 pro-teins were found between the control vs model group and the Sil-1 vs model group,and KEGG enrichment a-nalysis showed that MAPK,chemokines,VEGF and other signaling pathways were abundant.Western blot results showed that Sil-1 blocked the phosphorylation of ERK,JNK and p38 MAPK.Conclusions Sil-1 inhib-its the MAPK pathway by blocking the phosphorylation of JNK,ERK,and p38 MAPK,and achieves a protec-tive effect on rats with acute myocardial infarction.

Aim To investigate the effect of long-chain non-coding RNA(lncRNA)GS1-124K5.4 targeting regulation of PRDX6 on proliferation,migration and in-vasion of lung squamous carcinoma(LUSC)cells and the underlying mechanism.Methods The expression level of lncRNA GS1-124K5.4 in lung cancer tissues and adjacent tissues of 60 patients with LUSC were de-termined by fluorescence in situ hybridization.The ex-pression level of lncRNA GS1-124K5.4 in human nor-mal lung cells and LUSC cells were determined by qRT-PCR.Two kinds of LUSC cells(NCI-H 1703,SK-MES-1)with highest expression level of lncRNA GS1-124K5.4 were selected for subsequent experi-ments.The distribution of lncRNA GS1-124K5.4 in cells was studied by fluorescence in situ hybridization and prokaryotic separation.The effect of knockdown of lncRNA GS1-124K5.4 on proliferation of NCI-H1703 and SK-MES-1 cells was studied by CCK-8 experiment and cell clone formation experiment;the effect of knockdown of lncRNA GS1-124K5.4 on migration of NCI-H1703 and SK-MES-1 cells was studied by cell scratch experiment and Transwell cell migration experi-ment;and the effect of knockdown of lncRNA GS1-124K5.4 on invasion of NCI-H1703 and SK-MES-1 cells was studied by Transwell invasion experiment.The protein to be bound by lncRNA GS1-124K5.4 was detected by RNA pull-down combined with mass spec-trometry and immune-precipitation.The effect of knockdown of lncRNA GS1-124K5.4 targeting PRDX6 on proliferation,migration and invasion of NCI-H1703 and SK-MES-1 cells was studied.Results(1)The fluorescence intensity of lncRNA GS1-124K5.4 in lung squamous cell carcinoma increased compared with that in adjacent tissues(P＜0.05),and the expression of lncRNA GS1-124K5.4 was related with lymph node metastasis and clinical stage(P＜0.05).(2)The ex-pression level of lncRNA GS1-124K5.4 in NCI-H1703,NCI-H520 and SK-MES-1 cells significantly increased(P＜0.05).(3)The result of fluorescence in situ hybridization experiment and nucleoplasm sepa-ration experiment showed that lncRNA GS1-124K5.4 was mainly distributed in cell nucleus.(4)The prolif-eration,migration and invasion ability of NCI-H1703 and SK-MES-1 cells with knockdown of lncRNA GS1-124K5.4 significantly decreased(P＜0.05).(5)PRDX6 protein to be bound to LncRNA GS1-124K5.4 was determined by RNA pull-down combined with mass spectrometry and immunoprecipitation.(6)The prolif-eration,migration and invasion ability of NCI-H1703 and SK-MES-1 cells with overexpression of lncRNA GS1-124K5.4 significantly increased(P＜0.05);the proliferation,migration and invasion ability of NCI-H1703 and SK-MES-1 cells with knockdown of PRDX6 significantly decreased(P＜0.05);the proliferation,migration and invasion ability of NCI-H1703 and SK-MES-1 cells with overexpression of lncRNAGS1-124K5.4 and knockdown of PRDX6 showed no signifi-cant change(P＞0.05).Conclusions LncRNA GS1-124K5.4 is highly expressed in lung squamous cell carcinoma,and it may promote the proliferation,migration and invasion of lung squamous carcinoma cells by targeting the expression of PRDX6 protein.