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 Radix Angelica Sinensis and Radix Hedysari ultrafiltration(RAS-RH)on oxidative stress and inflammatory injury of human umbilical vein endothelial cells(HUVECs)induced by ionizing radiation.Methods The model of HUVECs damage induced by 6 Gy X-rays was estab-lished.HUVECs were treated with different concentra-tions of RAS-RH(100,200,400 μg·L-1).The proliferative activity of HUVECs was detected by CCK-8 method,the structural changes of mitochondria were observed by transmission electron microscope,the level of ROS was detected by DCFH-DA probe,the change of intracellular mitochondrial membrane potential was detected by JC-1 kit,and the apoptosis and cycle were detected by flow cytometry.The contents of IL-6 and TNF-α in cells were detected by ELISA.The activities of MDA,CAT,SOD and GSH-PX were detected by biochemical kit.The gene expression levels of Nrf2,HO-1,NF-κB,eNOS and IL-6 were detected by qRT-PCR,and the expression levels of Nrf2,HO-1,eNOS,NF-κB,p-NF-κB and IL-6 protein were detected by Western blot.Results Compared with the model group,RAS-RH could increase the activity of HUVECs induced by ionizing radiation,decrease the rate of ap-optosis,decrease the level of intracellular ROS,re-duce the injury of intracellular mitochondria,increase the level of mitochondrial membrane potential,promote the expression of Nrf2,HO-1 and eNOS,and inhibit the expression of NF-κB and IL-6.Conclusions RAS-RH has anti-radiation,antioxidant and anti-in-flammatory effects,which may reduce the oxidative stress and inflammatory damage of HUVECs induced by ionizing radiation by activating the activity of Nrf2/HO-1 signal pathway,thus promoting the activity of cell proliferation.

Objective To evaluate the efficacy of uterine artery embolization(UAE)combined with ultrasound-guided curettage in the treatment of type Ⅱ and type Ⅲ caesarean scar pregnancy(CSP).Methods The clinical data of 90 patient with CSP in our hospital were analyzed retrospectively,the patients were divided into type Ⅱ group and type Ⅲ group according to preoperative vaginal color Doppler ultrasound.Patients in both groups were treated with UAE combined with ultrasound-guided curettage.The intraoperative and postoperative conditions of patients between the two groups were compared and analyzed.Results The cure rate of type Ⅱ group(92.5%)was higher than that of type Ⅲ group(65.2%),the intraoperative blood loss,time of postoperative serum β-hCG turned negative,postoperative mass disappearance time of patients in type Ⅱ group were less/shorter than those in type Ⅲ group,the differences were statistically significant(P<0.05);there was no statistical difference in length of hospitalization or time to menstruation recovery of patients between the two groups(P>0.05).Conclusion UAE combined with ultrasound-guided curettage is ideal for patients with type Ⅱ CSP at 8 to 10 weeks of gestation,and can be used as a recommended treatment.However,the cure rate of this method for type Ⅲ CSP is low,the comprehensive choice should be considered,including the specific situation of the patient and the local medical level.

The aim of our research was to obtain Listeria bacteriophages from food and related environments,and conduc-ted the analysis of the electron microscopic morphology,host range specificity,and biological characteristics of the purified phages.The double-layer agar method and the spot test were employed for the isolation and identification of a virulent Listeria phage named LMLPA5,with the isolated strain Listeria in-nocua Lin08 as the host.Phage morphology was observed by transmission electron microscope.The biological characteris-tics of the phage were assessed by determining their host range,optimal multiplicity of infection(MOI),one-step growth curve,and physicochemical stability.Additionally,the preservation efficacy of the phage at 4 ℃,-20 ℃,and-80 ℃ was explored.The phage LMLPA5 belongs to the family Myoviridae based on morphology,exhibiting clear and transparent plaques without halo surrounded.Strains of sever-al Listeria species and different serotypes strains of Listeria monocytogenes were susceptible to lysis by LMLPA5,indica-ting its broad-spectrum activity against Listeria monocytogenes.Optimal MOIs and single-step growth curve analyses revealed optimal MOIs of 0.1 and latent period of 10 minutes for LMLPA5,with average burst size at 95.2 PFU/cell.LMLPA5 was sensitive to high temperatures,and completely inactivated after exposure to 70 ℃ for 1 h,while the phage remained stable for over 32 hours ranging from 4 ℃ to 40 ℃.Within the pH range of 4 to 10,phage titer remained stable and completely inactiva-ted until 60 minutes of ultraviolet exposure.LMLPA5 displayed insensitivity to chloroform,confirming its non-enveloped phage morphology.The phages remained stable for over 8 months when store at 4 ℃ and-80 ℃.The biological characteristics and lysis capacity of phage LMLPA5 were elucidated in this study,which provide the basis for further application.

The objective of this study was to determine the frequency and resistance patterns of ESBL-producing E.coli in lambs with diarrhea in the Kashi area,Xinjiang.The findings may provide guidance for the prevention and control of clinical E.coli disease.We collected 385 samples of perianal feces from lambs with diarrhea in the Kashgar area.From these samples,we isolated 371 strains of E.coli.We then used the double-paper-sheet synergistic method to screen for ESBL-producing E.coli.Additionally,we conducted analyses to identify drug-resistance genes,analyze drug resistance,and study the phylo-typing of the screened strains.Of 371 E.coli strains,204 were identified as ESBL-producing strains.The prevalence rates of blaCTX-M,blaCTX-M-1G,blaCTX-M-9G,and bla TEM resistance genes was 67.65％,69.12％,30.39％,and 63.73％,respectively.All ESBL-pro-ducing strains were resistant to multiple drugs,with resistance rates ranging from 90.69％to 100％for eight specific drugs:ampicillin,cefotaxime,gentamicin,enrofloxacin,azithromy-cin,tetracycline,chloramphenicol,methotrexate,and amitrazine.The phylogenetic subgroups of the strains were distributed primarily in groups A and D.Among group A strains,41.11％exhibited resistance to ten drugs,whereas among group D strains,40％exhibited resistance to 11 drugs.ESBL-pro-ducing strains of Escherichia coli are the main pathogens cau-sing diarrhea in lambs in the Kashgar region;group A is the main group,and all groups are multi-drug resistant.

Objective:To investigate the effects of Curcumol on the malignant biological characteristics of acute myeloid leukemia (AML)cells and its molecular mechanism,and to provide theoretical and experimental evidence for the anti-leukemia treatment of traditional Chinese medicine.Methods:After the AML cell lines HL-60 and KG-1 cells were treated different concentrations of with Curcumol.The proliferation activity of cells was detected by CCK-8 method,and the expression changes of apoptotic proteins and PI3 K/AKT signaling pathway proteins were detected by Western blot. Real-time quantitative fluorescence polymerase chain reaction (RT-qPCR ) was used to detect the expression of Caspase family mRNA.Results:Curcumol could inhibit the proliferation and induce apoptosis of HL-60 and KG-1 cells,promote apoptosis by up-regulating the expression of Bax and down-regulating the expression of Bcl-2 protein (P<0.05).When Curcumol interferes with HL-60 and KG-1 cells,it can also induce programmed cell death of AML by inhibiting PI3 K/AKT signaling pathway.In addition,after the intervention of Curcumol,the expression of Caspase 3,Caspase 6,Caspase 8 and Caspase 9 were up-regulated in HL-60 cells (P<0.05 ),the expression of Caspase 3,Caspase 8 and Caspase 9 were significantly up-regulated in KG-1 cells (P<0.01),while the expression of Caspase 6 was weakly affected (P<0.05 ),but low concentration of Curcumol (<60 μg/ml)had no effect on the expression of Caspase 6 in KG-1 cells (P>0.05).Conclusion:Curcumol may mediate the programmed death of AML cells by inhibiting the PI3K/AKT signaling pathway,affecting the expression of Bcl-2 family proteins,and promoting the activation of core members of Caspase family,so as to play an anti-leukemia role.

AIM To establish a UPLC-MS/MS method for the simultaneous content determination of hyperoside,kaempferol-3-O-rutinoside,esculin,chlorogenic acid,berberine,quercetin,rehmannioside D,palmatine,leonurin A,paeoniflorin,timosaponin BⅡand rutin in Guanhuangmu Granules.METHODS The analysis was performed on a 40℃ thermostatic Acquity UPLC HSS T3 column(100 mm×2.1 mm,1.8 μm),with the mobile phase comprising of 0.05%formic acid(containing 2 mmol/L ammonium acetate)-acetonitrile flowing at 0.3 mL/min in a gradient elution manner,and electron spray ionization source was adopted in positive and negative ion scanning.RESULTS Twelve constituents showed good linear relationships within their own ranges(r＞0.999 0),whose average recoveries were 93.46%-102.01%with the RSDs of 2.13%-3.65%.CONCLUSION This rapid,accurate,stable and sensitive method can be used for the quality control of Guanhuangmu Granules.

AIM To establish a UPLC-QTOF/MS method for the analyses of chemical constituents and constituents absorbed into blood from Runing Granules.METHODS Two rats were given intragastric administration of the aqueous solution of granules,after which blood collection was made at 0,0.5,1,2,4 h.The analysis was performed on a 40℃ thermostatic Acquity UPLC BEH C18 column(100 mm×2.1 mm,1.7 μm),with the mobile phases comprising of 0.1% formic aci D-acetonitrile(positive ion)or water-acetonitrile(negative ion)flowing at 0.3 mL/min in a gradient elution manner,and electron spray ionization source was adopted in positive and negative ion scanning.RESULTS Total 166 chemical constituents were identified,containing 44 flavonoids,17 terpenes,23 alkaloids,11 saponins,29 phenolic acids,13 quinones,10 organic acids,and 19 others,along with 11 constituents absorbed into blood.CONCLUSION This accurate and stable method can provide a data support for the clinical application of Runing Granules,and lay foundations for the further researches on their quality control and material basis.

AIM To establish a UPLC-QTOF/MS method for the analyses of chemical constituents and constituents absorbed into blood from Qili Qiangxin Capsules by UPLC-QTOF/MS.METHODS The rats with heart failure after myocardial infarction were given intragastric administration of 0.5%CMC-Na suspension of Qili Qiangxin Capsules(crude drug dosage was 0.9 g/mL)for 4 weeks,after which blood collection was made.The analysis was performed on a 40℃thermostatic Acquity UPLC BEH C18 Column(100 mm×2.1 mm,1.7 μm),with the mobile phase comprising of 0.1%formic acid-acetonitrile(positive ion manner)or water-acetonitrile(negative ion manner)flowing at 0.3 mL/min in a gradient elution manner,and electron spray ionization source was adopted in positive and negative ion scanning.RESULTS Total 151 constituents were identified,containing 38 flavonoids,36 terpenoids,23 alkaloids,11 saponins,11 phenylpropanol,10 phenolic acids,4 organic acids,4 cardiac glycosides and 14 others,along with 35 constituents absorbed into blood.CONCLUSION This accurate and stable method can provide data support for the rational clinical application of Qili Qiangxin Capsules,and lay foundation for the research on related effector substances of other Chinese traditional patent medicines.

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.