Marker-free GFP transgenic tobacco plants were constructed based on Cre/lox site-specific recombination system. A GFP gene was introduced into the tobacco genome using the Bar gene as a linked selectable marker flanke...Marker-free GFP transgenic tobacco plants were constructed based on Cre/lox site-specific recombination system. A GFP gene was introduced into the tobacco genome using the Bar gene as a linked selectable marker flanked by recombination sites in a directed orientation. The Bar gene expression box was subsequently excised from the plant genome by a strategy of Cre gene retransformation. After removal of the Cre-NPT Ⅱ locus by genetic segregation through self-cross, plants that incorporated only the GFP transgene were obtained. Transgenic tobacco plants mediated by Agrobacterium tumefaciens were obtained, which resisted herbicide Basta and GFP expressed well, then the Cre gene was subsequently introduced into 5 plants of them, respectively, by retransformation. The leaf disks from Cre transgenic plants were used to test the resistance to Basta on the medium with 8 mg L-1 of PPT. The results showed that few discs were able to regenerate normally, and the excision at 76-100% efficiency depended on individual retransformation events. Evidence for a precise recombination event was confirmed by cloning the nucleotides sequence surrounding the lox sites of the Basta sensitive plants. The result indicated that the excision event in the recombination sites was precise and conservative, without loss or alteration of any submarginal nucleotides of the recombination sites. Bar gene excised plants were selfpollinated to allow segregation of the GFP gene from the Cre-NPT Ⅱ locus. The progenies from self-pollinated plants were scored for Kan senstivity, then the segregation of GFP gene from Cre-NPT Ⅱ locus in the Kan senstive plants were confirmed by PCR analysis subsequently. Hence, constructing marker-free transgenic tobacco plants by Cre/lox sitespecific recombination system was reliable, and the strategy presented here should be applicable to other plants for the construction of marker-free transgenic plants as well.展开更多
The purpose of this study was to demonstrate that actinomyces phage R4 integrase Sre protein efficiently mediate site-specific recombination in Escherichia coli. An intramolecular recombination assay system in E.coli ...The purpose of this study was to demonstrate that actinomyces phage R4 integrase Sre protein efficiently mediate site-specific recombination in Escherichia coli. An intramolecular recombination assay system in E.coli was constructed. The plasmid pBZP contains attB and attP sites in direct orientation flanking a lacZ gene. When pBZP was introduced into E.coli cells, in which the plasmid pSRE4 containing sre gene was resident, Sre protein catalyzed integration of attP into attB site, resulting in excision of the lacZ gene. This integration changed bacteria colonies from blue to white on agar plates containing X-Gal, which showed that the lacZ was removed. The integrant DNAs were identified by enzyme digestion, PCR and DNA sequencing. The minimal sizes of attB and attP were 50 bp and 47 bp for 100% recombination efficiency. The phage recombinase Sre efficiently integrated attP into attB site to create attR and attL in E.coli host environment without Streptomyces specific cofactors. This intramolecular assay system is a simple and efficient system for Sre-mediated recombination in E.coli.展开更多
O3-type layered oxides have garnered great attention as cathode materials for sodium-ion batteries because of their abundant reserves and high theoretical capacity.However,challenges persist in the form of uncontrolla...O3-type layered oxides have garnered great attention as cathode materials for sodium-ion batteries because of their abundant reserves and high theoretical capacity.However,challenges persist in the form of uncontrollable phase transitions and intricate Na^(+)diffusion pathways during cycling,resulting in compromised structural stability and reduced capacity over cycles.This study introduces a special approach employing site-specific Ca/F co-substitution within the layered structure of O_(3)-NaNi_(0.5)Mn_(0.5)O_(2) to effectively address these issues.Herein,the strategically site-specific doping of Ca into Na sites and F into O sites not only expands the Na^(+)diffusion pathways but also orchestrates a mild phase transition by suppressing the Na^(+)/vacancy ordering and providing strong metal-oxygen bonding strength,respectively.The as-synthesized Na_(0.95)Ca_(0.05)Ni_(0.5)Mn_(0.5)O_(1.95)F_(0.05)(NNMO-CaF)exhibits a mild O3→O3+O'3→P3 phase transition with minimized interlayer distance variation,leading to enhanced structural integrity and stability over extended cycles.As a result,NNMO-CaF delivers a high specific capacity of 119.5 mA h g^(-1)at a current density of 120 mA g^(-1)with a capacity retention of 87.1%after 100 cycles.This study presents a promising strategy to mitigate the challenges posed by multiple phase transitions and augment Na^(+)diffusion kinetics,thus paving the way for high-performance layered cathode materials in sodium-ion batteries.展开更多
Both FRT-FRT and LoxP-LoxP sites that are the target sepuences of site-specific recombinases have been constructed in a vector, called C4LFY, using the recombinant DNA technigue. C4LFY also contains P elements, 2 exon...Both FRT-FRT and LoxP-LoxP sites that are the target sepuences of site-specific recombinases have been constructed in a vector, called C4LFY, using the recombinant DNA technigue. C4LFY also contains P elements, 2 exons and 1 intron of Drosophila yellow gene, yellow promoter and enhancers, and flanking DNA. Since C4LFY made use of two pairs of FRT and LoxP sites, this vector included two site-specific recombination systems. C4LFY was then integrated into Drosophila genome by P-element-mediated germ line transformation. in the presence of the FLP or Cre recombinase, either FLP/FRT or Cre/LoxP recombination reaction was successfully created at the same position in the genome. Using this system, the molecular basis of yellow gene expression and regulation during development have been investigated. Results indicate that the tissue-specific expression of yellow gene is directly regulated by transcriptional enhancers. in addition, the 5’ and 3’ genomic sequences flanking the yellow gene have been展开更多
For the temporally and spatially regulated expression of the barnase gene in plant, two kinds of plasmids with ere gene and its directly repeat recognition sites lox from bacteriophage P1 were constructed and co-trans...For the temporally and spatially regulated expression of the barnase gene in plant, two kinds of plasmids with ere gene and its directly repeat recognition sites lox from bacteriophage P1 were constructed and co-transformed into tobacco by agrobacterium mediated procedure. The transgenic plants were conformed by PCR analysis. The blocking fragment between the two lox directly repeat sites was excised by Cre protein in the transgenic plant genome. Cloning and seguencing the DNA fragment from the co-transformed plant DNA showed that the precise DNA excision occurred in transgenic tobacco genome directed by Cre//ox site-specif ic recombination .展开更多
Objective:The choice of chemotherapeutic regimen for triple-negative breast cancer(TNBC)remains controversial.Homologous recombination deficiency(HRD)has attracted increasing attention in informing chemotherapy treatm...Objective:The choice of chemotherapeutic regimen for triple-negative breast cancer(TNBC)remains controversial.Homologous recombination deficiency(HRD)has attracted increasing attention in informing chemotherapy treatment.This study was aimed at investigating the feasibility of HRD as a clinically actionable biomarker for platinum-containing and platinum-free therapy.Methods:Chinese patients with TNBC who received chemotherapy between May 1,2008 and March 31,2020 were retrospectively analyzed with a customized 3D-HRD panel.HRD positivity was defined by an HRD score≥30 or deleterious BRCA1/2 mutation.A total of 386 chemotherapy-treated patients with TNBC were screened from a surgical cohort(NCT01150513)and a metastatic cohort,and 189 patients with available clinical and tumor sequencing data were included.Results:In the entire cohort,49.2%(93/189)of patients were identified as HRD positive(40 with deleterious BRCA1/2 mutations and 53 with BRCA1/2 intact with an HRD score of≥30).In the first-line metastatic setting,platinum therapy was associated with longer median progression-free survival(mPFS)than platinum-free therapy[9.1 vs.3.0 months;hazard ratio(HR),0.43;95%confidence interval 0.22–0.84;P=0.01].Among HRD-positive patients,the mPFS was significantly longer in those treated with platinum rather than platinum-free therapy(13.6 vs.2.0 months;HR,0.11;P=0.001).Among patients administered a platinum-free regimen,HRD-negative patients showed a PFS significantly superior to that of HRD-positive patients(P=0.02;treatment-biomarker P-interaction=0.001).Similar results were observed in the BRCA1/2-intact subset.In the adjuvant setting,HRD-positive patients tended to benefit more from platinum chemotherapy than from platinum-free chemotherapy(P=0.05,P-interaction=0.02).Conclusions:HRD characterization may guide decision-making regarding the use of platinum treatment in patients with TNBC in both adjuvant and metastatic settings.展开更多
Dielectronic recombination(DR)is one of the dominant electron-ion recombination mechanisms for most highly charged ions(HCIs)in cosmic plasmas,and thus,it determines the charge state distribution and ionization balanc...Dielectronic recombination(DR)is one of the dominant electron-ion recombination mechanisms for most highly charged ions(HCIs)in cosmic plasmas,and thus,it determines the charge state distribution and ionization balance therein.To reliably interpret spectra from cosmic sources and model the astrophysical plasmas,precise DR rate coefficients are required to build up an accurate understanding of the ionization balance of the sources.The main cooler storage ring(CSRm)and the experimental cooler storage ring(CSRe)at the Heavy-Ion Research Facility in Lanzhou(HIRFL)are both equipped with electron cooling devices,which provide an excellent experimental platform for electron-ion collision studies for HCIs.Here,the status of the DR experiments at the HIRFL-CSR is outlined,and the DR measurements with Na-like Kr25^(+)ions at the CSRm and CSRe are taken as examples.In addition,the plasma recombination rate coefficients for Ar12^(+),14^(+),Ca14^(+),16^(+),17^(+),Ni19^(+),and Kr25^(+)ions obtained at the HIRFL-CSR are provided.All the data presented in this paper are openly available at https://doi.org/10.57760/sciencedb.j00113.00092.展开更多
The bifacial silicon solar cell, placed at temperature (T) and illuminated from the back side by monochromatic light in frequency modulation (ω), is studied from the frequency dynamic diffusion equation, relative to ...The bifacial silicon solar cell, placed at temperature (T) and illuminated from the back side by monochromatic light in frequency modulation (ω), is studied from the frequency dynamic diffusion equation, relative to the density of excess minority carriers in the base. The expressions of the dynamic recombination velocities of the minority carriers on the rear side of the base Sb1(D(ω, T);H) and Sb2(α, D(ω, T);H), are analyzed as a function of the dynamic diffusion coefficient (D(ω, T)), the absorption coefficient (α(λ)) and the thickness of the base (H). Thus their graphic representation makes it possible to go up, to the base optimum thickness (Hopt(ω, T)), for different temperature values and frequency ranges of modulation of monochromatic light, of strong penetration. The base optimum thickness (Hopt(ω, T)) decreases with temperature, regardless of the frequency range and allows the realization of the solar cell with few material (Si).展开更多
Objective: This paper aims to investigate the effect of applying recombinant human brain natriuretic peptide in patients with heart failure combined with hypotension. Recombinant human brain natriuretic peptide is a s...Objective: This paper aims to investigate the effect of applying recombinant human brain natriuretic peptide in patients with heart failure combined with hypotension. Recombinant human brain natriuretic peptide is a synthetic polypeptide drug that is primarily used to treat acute heart failure. Its mechanism of action closely mimics that of human endogenous brain natriuretic peptide. By binding to receptors on cardiomyocytes, it exerts its pharmacological effects. Methods: For the study, 76 heart failure patients with hypotension were selected from our hospital between May 2022 and June 2023. These patients were divided into two groups: a control group and an observation group, each comprising 38 patients. The control group received dopamine treatment, while the observation group was treated with recombinant brain natriuretic peptide. The objective was to compare the effects of the treatments in both groups by analyzing cardiac function indices and levels of vasoactive substances to identify any significant differences in outcomes. Results: The overall response rate of the patients in the observation group and the control group was 94.74% and 73.68%, significantly higher as compared with the observation group (P 0.05). After the following treatment, BNP, ANNP and urine output in the observation group were significantly different compared with the control group, of the statistical significance (P Conclusion: For the treatment of heart failure patients with hypotension, the clinical application of recombinant human brain natriuretic peptide is the most ideal, and significantly improves the cardiac function of patients, which is worth popularizing.展开更多
BACKGROUND Primary sclerosing cholangitis(PSC)is characterized by chronic inflammation and it predisposes to cholangiocarcinoma due to lack of effective treatment options.Recombinant adeno-associated virus(rAAV)provid...BACKGROUND Primary sclerosing cholangitis(PSC)is characterized by chronic inflammation and it predisposes to cholangiocarcinoma due to lack of effective treatment options.Recombinant adeno-associated virus(rAAV)provides a promising platform for gene therapy on such kinds of diseases.A microRNA(miRNA)let-7a has been reported to be associated with the progress of PSC but the potential therapeutic implication of inhibition of let-7a on PSC has not been evaluated.AIM To investigate the therapeutic effects of inhibition of a miRNA let-7a transferred by recombinant adeno-associated virus 8(rAAV8)on a xenobiotic-induced mouse model of sclerosing cholangitis.METHODS A xenobiotic-induced mouse model of sclerosing cholangitis was induced by 0.1% 3,5-Diethoxycarbonyl-1,4-Dihydrocollidine(DDC)feeding for 2 wk or 6 wk.A single dose of rAAV8-mediated anti-let-7a-5p sponges or scramble control was injected in vivo into mice onset of DDC feeding.Upon sacrifice,the liver and the serum were collected from each mouse.The hepatobiliary injuries,hepatic inflammation and fibrosis were evaluated.The targets of let-7a-5p and downstream molecule NF-κB were detected using Western blot.RESULTS rAAV8-mediated anti-let-7a-5p sponges can depress the expression of let-7a-5p in mice after DDC feeding for 2 wk or 6 wk.The reduced expression of let-7a-5p can alleviate hepato-biliary injuries indicated by serum markers,and prevent the proliferation of cholangiocytes and biliary fibrosis.Furthermore,inhibition of let-7a mediated by rAAV8 can increase the expression of potential target molecules such as suppressor of cytokine signaling 1 and Dectin1,which consequently inhibit of NF-κB-mediated hepatic inflammation.CONCLUSION Our study demonstrates that a rAAV8 vector designed for liver-specific inhibition of let-7a-5p can potently ameliorate symptoms in a xenobiotic-induced mouse model of sclerosing cholangitis,which provides a possible clinical translation of PSC of human.展开更多
BACKGROUND Dry eye syndrome(DES)after diabetic cataract surgery can seriously affect the patient’s quality of life.Therefore,effective alleviation of symptoms in patients with this disease has important clinical sign...BACKGROUND Dry eye syndrome(DES)after diabetic cataract surgery can seriously affect the patient’s quality of life.Therefore,effective alleviation of symptoms in patients with this disease has important clinical significance.AIM To explore the clinical effect of recombinant human epidermal growth factor(rhEGF)plus sodium hyaluronate(SH)eye drops on DES after cataract surgery in patients with diabetes.METHODS We retrospectively evaluated 82 patients with diabetes who experienced DES after cataract surgery at Tianjin Beichen Hospital,Affiliated Hospital of Nankai University between April 2021 and April 2023.They were classified into an observation group(42 cases,rhEGF+SH eye drops)and a control group(40 cases,SH eye drops alone),depending on the different treatment schemes.The therapeutic efficacy,dry eye symptom score,tear film breakup time(TFBUT),basic tear secretion score[assessed using Schirmer I test(SIt)],corneal fluorescein staining(FL)score,tear inflammatory markers,adverse reactions during treat-ment,and treatment satisfaction were compared between the two groups.RESULTS Therapeutic efficacy was higher in the observation group compared with the control group.Both groups showed improved TFBUT and dry eye,as well as improved SIt and FL scores after treatment,with a more pronounced improvement in the observation group.Although no marked differences in adverse reactions were observed between the two groups,treatment satisfaction was higher in the observation group.CONCLUSION rhEGF+SH eye drops rendered clinical benefits to patients by effectively ameliorating dry eye and visual impairment with favorable efficacy,fewer adverse reactions,and high safety levels.Thus,this treatment should be promoted in clinical practice.展开更多
The multi-factor recombination and processes superimposition model for hydrocarbon accumulation is put forward in view of the hydrocarbon geological characteristics of multiple episodes of structural evolution, multip...The multi-factor recombination and processes superimposition model for hydrocarbon accumulation is put forward in view of the hydrocarbon geological characteristics of multiple episodes of structural evolution, multiple sets of source-reservoir-seal assemblage, multiple cycles of hydrocarbon accumulation and multiple episodes of readjustment and reconstruction in the complex superimposed basins in China. It is a system including theories and methods that can help to predict favorable exploration regions. According to this model, the basic discipline for hydrocarbon generation, evolution and distribution in the superimposed basins can be summarized in multi-factor recombination, processes superimposition, multiple stages of oil filling and latest stage preservation. With the Silurian of the Tarim basin as an example, based on the reconstruction of the evolution history of the four factors (paleo-anticline, source rock, regional cap rock and kinematic equilibrium belt) controlling hydrocarbon accumulation, this model was adopted to predict favorable hydrocarbon accumulation areas and favorable exploration regions following structural destruction in three stages of oil filling, to provide guidance for further exploration ofoil and gas in the Silurian of the Tarim basin.展开更多
Ovarian carcinoma is the most lethal gynecologic malignancy. Resistance to platinum is considered the major problem afecting prognosis. Our recent study established that micro RNA-506(mi R-506) expression was closely ...Ovarian carcinoma is the most lethal gynecologic malignancy. Resistance to platinum is considered the major problem afecting prognosis. Our recent study established that micro RNA-506(mi R-506) expression was closely associated with progression-free survival and overall survival in two independent patient cohorts totaling 598 epithelial ovarian cancer cases. Further functional study demonstrated that mi R-506 could augment the response to cisplatin and olaparib through targeting RAD51 and suppressing homologous recombination in a panel of ovarian cancer cell lines. Systemic delivery of mi R-506 in an orthotopic ovarian cancer mouse model signiicantly augmented the cisplatin response, thus recapitulating the clinical observation. Therefore, mi R-506 plays a functionally important role in homologous recombination and has important therapeutic value for sensitizing cancer cells to chemotherapy, especially in chemo-resistant patients with attenuated expression of mi R-506.展开更多
Infertility is a common problem that affects approximately 15% of the population. Although many advances have been made in the treatment of infertility, the molecular and genetic causes of male infertility remain larg...Infertility is a common problem that affects approximately 15% of the population. Although many advances have been made in the treatment of infertility, the molecular and genetic causes of male infertility remain largely elusive. This review will present a summary of our current knowledge on the genetic origin of male infertility and the key events of male meiosis. It focuses on chromosome synapsis and meiotic recombination and the problems that arise when errors in these processes occur, specifically meiotic arrest and chromosome aneuploidy, the leading cause of pregnancy loss in humans. In addition, meiosis-specific candidate genes will be discussed, including a discussion on why we have been largely unsuccessful at identifying disease-causing mutations in infertile men. Finally clinical applications of sperm aneuploidy screening will be touched upon along with future prospective clinical tests to better characterize male infertility in a move towards personalized medicine.展开更多
INTRODUCTIONHelicobacter pylori (H . pylori) is associated with the development of chronic gastritis ,peptic ulcer and gastric cancer and gastric MALT lymphoma[1-9],H .pylori has many antigens ,including urease ,heat ...INTRODUCTIONHelicobacter pylori (H . pylori) is associated with the development of chronic gastritis ,peptic ulcer and gastric cancer and gastric MALT lymphoma[1-9],H .pylori has many antigens ,including urease ,heat shock protein and vacuolating cytotoxin and so on ,and urease is an important factor in the colinization of the gastric mucosa and suspected to cause damage to the gastric mucosa[10-14].At the same time ,urdase is also one of the important protective antigens .展开更多
The transgenic tobacco plants transformed with movement protein gene of Tomato mosaic virus (ToMV) or Tobacco mosaic virus (TMV) and partial replicase gene of Cucumber mosaic virus (CMV) P1 isolate (CMV-P1), were inoc...The transgenic tobacco plants transformed with movement protein gene of Tomato mosaic virus (ToMV) or Tobacco mosaic virus (TMV) and partial replicase gene of Cucumber mosaic virus (CMV) P1 isolate (CMV-P1), were inoculated with Potato virus X, Potato virus Y, TMV and CMV isolate RB (CMV-RB), respectively. Symptom observation showed there were no symptom differences in transgenic tobacco plants as compared with those in non-transgenie tobacco plants. ELISA also illustrated that the virus concentrations in the transgenic plants were similar to those in non-transgenic plants, indicating that no synergism is found in these plants. The transgenic tobacco plants expressing movement protein gene of ToMV or partial replicase gene of CMV-P1 were inoculated with TMV and CMV-RB, respectively. The local or systemic infected leaves were then used for elucidation of the possible virus recombination in transgenic plants with biological infectivity test, ELISA and immuno-capture RT-PCR. Within 16 months, no recombination was found between transformed genes and inoculated virus genomes. The research provides fundamental data for understanding of the possible risk of the transgenic plants expressing viral sequences.展开更多
A new tunnel recombination junction is fabricated for n-i-p type micromorph tandem solar cells. We insert a thin heavily doped hydrogenated amorphous silicon (a-Si:H) p^+ recombination layer between the n a-Si:H ...A new tunnel recombination junction is fabricated for n-i-p type micromorph tandem solar cells. We insert a thin heavily doped hydrogenated amorphous silicon (a-Si:H) p^+ recombination layer between the n a-Si:H and the p hydrogenated nanocrystalline silicon (nc-Si:H) layers to improve the performance of the n-i-p tandem solar cells. The effects of the boron doping gas ratio and the deposition time of the p-a-Si:H recombination layer on the tunnel recombination junctions have been investigated. The current-voltage characteristic of the tunnel recombination junction shows a nearly ohmic characteristic, and the resistance of the tunnel recombination junction can be as low as 1.5 Ω-cm^2 by using the optimized p-a-Si:H recombination layer. We obtain tandem solar cells with open circuit voltage Voc = 1.4 V, which is nearly the sum of the Vocs of the two corresponding single cells, indicating no Voc losses at the tunnel recombination junction.展开更多
The KLL dielectronic recombination (DR) processes of ions from highly charged helium-like to oxygen-like krypton, iodine and barium ions are studied systematically in the relativistic distorted-wave approximation wi...The KLL dielectronic recombination (DR) processes of ions from highly charged helium-like to oxygen-like krypton, iodine and barium ions are studied systematically in the relativistic distorted-wave approximation with configuration interaction. The KLL DR resonant energies, the corresponding resonant strengths and the theoretical spectra for each highly charged ion species are obtained. The results accord well with other available values. The behaviour of KLL resonant strengths for He-like ions with atomic number Z is analysed.展开更多
This paper reports that a double N layer (a-Si:H/μc-Si:H) is used to substitute the single microcrystalline silicon n layer (n-μc-Si:H) in n/p tunnel recombination junction between subcells in a-Si:H/μc-Si...This paper reports that a double N layer (a-Si:H/μc-Si:H) is used to substitute the single microcrystalline silicon n layer (n-μc-Si:H) in n/p tunnel recombination junction between subcells in a-Si:H/μc-Si:H tandem solar cells. The electrical transport and optical properties of these tunnel recombination junctions are investigated by current voltage measurement and transmission measurement. The new n/p tunnel recombination junction shows a better ohmic contact. In addition, the n/p interface is exposed to the air to examine the effect of oxidation on the tunnel recombination junction performance. The open circuit voltage and FF of a-Si:H/μc-Si:H tandem solar cell are all improved and the current leakage of the subcells can be effectively prevented efficiently when the new n/p junction is implemented as tunnel recombination junction.展开更多
基金the National Natural Science Foundation of China (30200185)the Science Foundation of Committee of Education of Chongqing Municipality,China (030208)
文摘Marker-free GFP transgenic tobacco plants were constructed based on Cre/lox site-specific recombination system. A GFP gene was introduced into the tobacco genome using the Bar gene as a linked selectable marker flanked by recombination sites in a directed orientation. The Bar gene expression box was subsequently excised from the plant genome by a strategy of Cre gene retransformation. After removal of the Cre-NPT Ⅱ locus by genetic segregation through self-cross, plants that incorporated only the GFP transgene were obtained. Transgenic tobacco plants mediated by Agrobacterium tumefaciens were obtained, which resisted herbicide Basta and GFP expressed well, then the Cre gene was subsequently introduced into 5 plants of them, respectively, by retransformation. The leaf disks from Cre transgenic plants were used to test the resistance to Basta on the medium with 8 mg L-1 of PPT. The results showed that few discs were able to regenerate normally, and the excision at 76-100% efficiency depended on individual retransformation events. Evidence for a precise recombination event was confirmed by cloning the nucleotides sequence surrounding the lox sites of the Basta sensitive plants. The result indicated that the excision event in the recombination sites was precise and conservative, without loss or alteration of any submarginal nucleotides of the recombination sites. Bar gene excised plants were selfpollinated to allow segregation of the GFP gene from the Cre-NPT Ⅱ locus. The progenies from self-pollinated plants were scored for Kan senstivity, then the segregation of GFP gene from Cre-NPT Ⅱ locus in the Kan senstive plants were confirmed by PCR analysis subsequently. Hence, constructing marker-free transgenic tobacco plants by Cre/lox sitespecific recombination system was reliable, and the strategy presented here should be applicable to other plants for the construction of marker-free transgenic plants as well.
文摘The purpose of this study was to demonstrate that actinomyces phage R4 integrase Sre protein efficiently mediate site-specific recombination in Escherichia coli. An intramolecular recombination assay system in E.coli was constructed. The plasmid pBZP contains attB and attP sites in direct orientation flanking a lacZ gene. When pBZP was introduced into E.coli cells, in which the plasmid pSRE4 containing sre gene was resident, Sre protein catalyzed integration of attP into attB site, resulting in excision of the lacZ gene. This integration changed bacteria colonies from blue to white on agar plates containing X-Gal, which showed that the lacZ was removed. The integrant DNAs were identified by enzyme digestion, PCR and DNA sequencing. The minimal sizes of attB and attP were 50 bp and 47 bp for 100% recombination efficiency. The phage recombinase Sre efficiently integrated attP into attB site to create attR and attL in E.coli host environment without Streptomyces specific cofactors. This intramolecular assay system is a simple and efficient system for Sre-mediated recombination in E.coli.
基金supported by the Science and Technology Program of Suzhou(ST202304)the National Natural Science Foundation of China(12275189)+1 种基金the Collaborative Innovation Center of Suzhou Nano Science&Technologythe 111 project。
文摘O3-type layered oxides have garnered great attention as cathode materials for sodium-ion batteries because of their abundant reserves and high theoretical capacity.However,challenges persist in the form of uncontrollable phase transitions and intricate Na^(+)diffusion pathways during cycling,resulting in compromised structural stability and reduced capacity over cycles.This study introduces a special approach employing site-specific Ca/F co-substitution within the layered structure of O_(3)-NaNi_(0.5)Mn_(0.5)O_(2) to effectively address these issues.Herein,the strategically site-specific doping of Ca into Na sites and F into O sites not only expands the Na^(+)diffusion pathways but also orchestrates a mild phase transition by suppressing the Na^(+)/vacancy ordering and providing strong metal-oxygen bonding strength,respectively.The as-synthesized Na_(0.95)Ca_(0.05)Ni_(0.5)Mn_(0.5)O_(1.95)F_(0.05)(NNMO-CaF)exhibits a mild O3→O3+O'3→P3 phase transition with minimized interlayer distance variation,leading to enhanced structural integrity and stability over extended cycles.As a result,NNMO-CaF delivers a high specific capacity of 119.5 mA h g^(-1)at a current density of 120 mA g^(-1)with a capacity retention of 87.1%after 100 cycles.This study presents a promising strategy to mitigate the challenges posed by multiple phase transitions and augment Na^(+)diffusion kinetics,thus paving the way for high-performance layered cathode materials in sodium-ion batteries.
文摘Both FRT-FRT and LoxP-LoxP sites that are the target sepuences of site-specific recombinases have been constructed in a vector, called C4LFY, using the recombinant DNA technigue. C4LFY also contains P elements, 2 exons and 1 intron of Drosophila yellow gene, yellow promoter and enhancers, and flanking DNA. Since C4LFY made use of two pairs of FRT and LoxP sites, this vector included two site-specific recombination systems. C4LFY was then integrated into Drosophila genome by P-element-mediated germ line transformation. in the presence of the FLP or Cre recombinase, either FLP/FRT or Cre/LoxP recombination reaction was successfully created at the same position in the genome. Using this system, the molecular basis of yellow gene expression and regulation during development have been investigated. Results indicate that the tissue-specific expression of yellow gene is directly regulated by transcriptional enhancers. in addition, the 5’ and 3’ genomic sequences flanking the yellow gene have been
文摘For the temporally and spatially regulated expression of the barnase gene in plant, two kinds of plasmids with ere gene and its directly repeat recognition sites lox from bacteriophage P1 were constructed and co-transformed into tobacco by agrobacterium mediated procedure. The transgenic plants were conformed by PCR analysis. The blocking fragment between the two lox directly repeat sites was excised by Cre protein in the transgenic plant genome. Cloning and seguencing the DNA fragment from the co-transformed plant DNA showed that the precise DNA excision occurred in transgenic tobacco genome directed by Cre//ox site-specif ic recombination .
基金granted by Capital’s Funds for Health Improvement and Research(Grant No.2018-2-4023)the National Natural Science Foundation of China(Grant No.82001559)。
文摘Objective:The choice of chemotherapeutic regimen for triple-negative breast cancer(TNBC)remains controversial.Homologous recombination deficiency(HRD)has attracted increasing attention in informing chemotherapy treatment.This study was aimed at investigating the feasibility of HRD as a clinically actionable biomarker for platinum-containing and platinum-free therapy.Methods:Chinese patients with TNBC who received chemotherapy between May 1,2008 and March 31,2020 were retrospectively analyzed with a customized 3D-HRD panel.HRD positivity was defined by an HRD score≥30 or deleterious BRCA1/2 mutation.A total of 386 chemotherapy-treated patients with TNBC were screened from a surgical cohort(NCT01150513)and a metastatic cohort,and 189 patients with available clinical and tumor sequencing data were included.Results:In the entire cohort,49.2%(93/189)of patients were identified as HRD positive(40 with deleterious BRCA1/2 mutations and 53 with BRCA1/2 intact with an HRD score of≥30).In the first-line metastatic setting,platinum therapy was associated with longer median progression-free survival(mPFS)than platinum-free therapy[9.1 vs.3.0 months;hazard ratio(HR),0.43;95%confidence interval 0.22–0.84;P=0.01].Among HRD-positive patients,the mPFS was significantly longer in those treated with platinum rather than platinum-free therapy(13.6 vs.2.0 months;HR,0.11;P=0.001).Among patients administered a platinum-free regimen,HRD-negative patients showed a PFS significantly superior to that of HRD-positive patients(P=0.02;treatment-biomarker P-interaction=0.001).Similar results were observed in the BRCA1/2-intact subset.In the adjuvant setting,HRD-positive patients tended to benefit more from platinum chemotherapy than from platinum-free chemotherapy(P=0.05,P-interaction=0.02).Conclusions:HRD characterization may guide decision-making regarding the use of platinum treatment in patients with TNBC in both adjuvant and metastatic settings.
基金supported by the National Natural Science Foundation of China (Grant Nos. U1932207, 11904371, and 12104437)the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No. XDB34020000)
文摘Dielectronic recombination(DR)is one of the dominant electron-ion recombination mechanisms for most highly charged ions(HCIs)in cosmic plasmas,and thus,it determines the charge state distribution and ionization balance therein.To reliably interpret spectra from cosmic sources and model the astrophysical plasmas,precise DR rate coefficients are required to build up an accurate understanding of the ionization balance of the sources.The main cooler storage ring(CSRm)and the experimental cooler storage ring(CSRe)at the Heavy-Ion Research Facility in Lanzhou(HIRFL)are both equipped with electron cooling devices,which provide an excellent experimental platform for electron-ion collision studies for HCIs.Here,the status of the DR experiments at the HIRFL-CSR is outlined,and the DR measurements with Na-like Kr25^(+)ions at the CSRm and CSRe are taken as examples.In addition,the plasma recombination rate coefficients for Ar12^(+),14^(+),Ca14^(+),16^(+),17^(+),Ni19^(+),and Kr25^(+)ions obtained at the HIRFL-CSR are provided.All the data presented in this paper are openly available at https://doi.org/10.57760/sciencedb.j00113.00092.
文摘The bifacial silicon solar cell, placed at temperature (T) and illuminated from the back side by monochromatic light in frequency modulation (ω), is studied from the frequency dynamic diffusion equation, relative to the density of excess minority carriers in the base. The expressions of the dynamic recombination velocities of the minority carriers on the rear side of the base Sb1(D(ω, T);H) and Sb2(α, D(ω, T);H), are analyzed as a function of the dynamic diffusion coefficient (D(ω, T)), the absorption coefficient (α(λ)) and the thickness of the base (H). Thus their graphic representation makes it possible to go up, to the base optimum thickness (Hopt(ω, T)), for different temperature values and frequency ranges of modulation of monochromatic light, of strong penetration. The base optimum thickness (Hopt(ω, T)) decreases with temperature, regardless of the frequency range and allows the realization of the solar cell with few material (Si).
文摘Objective: This paper aims to investigate the effect of applying recombinant human brain natriuretic peptide in patients with heart failure combined with hypotension. Recombinant human brain natriuretic peptide is a synthetic polypeptide drug that is primarily used to treat acute heart failure. Its mechanism of action closely mimics that of human endogenous brain natriuretic peptide. By binding to receptors on cardiomyocytes, it exerts its pharmacological effects. Methods: For the study, 76 heart failure patients with hypotension were selected from our hospital between May 2022 and June 2023. These patients were divided into two groups: a control group and an observation group, each comprising 38 patients. The control group received dopamine treatment, while the observation group was treated with recombinant brain natriuretic peptide. The objective was to compare the effects of the treatments in both groups by analyzing cardiac function indices and levels of vasoactive substances to identify any significant differences in outcomes. Results: The overall response rate of the patients in the observation group and the control group was 94.74% and 73.68%, significantly higher as compared with the observation group (P 0.05). After the following treatment, BNP, ANNP and urine output in the observation group were significantly different compared with the control group, of the statistical significance (P Conclusion: For the treatment of heart failure patients with hypotension, the clinical application of recombinant human brain natriuretic peptide is the most ideal, and significantly improves the cardiac function of patients, which is worth popularizing.
基金Supported by the National Natural Science Foundation of China,No.82172297Natural Science Foundation of Jiangsu Province of China,No.BK20211346 and No.BK20201011+1 种基金Natural Science Foundation of Jiangsu Higher Education Institutions of China,No.22KJA310007Xuzhou Science and Technology Project,No.KC22055.
文摘BACKGROUND Primary sclerosing cholangitis(PSC)is characterized by chronic inflammation and it predisposes to cholangiocarcinoma due to lack of effective treatment options.Recombinant adeno-associated virus(rAAV)provides a promising platform for gene therapy on such kinds of diseases.A microRNA(miRNA)let-7a has been reported to be associated with the progress of PSC but the potential therapeutic implication of inhibition of let-7a on PSC has not been evaluated.AIM To investigate the therapeutic effects of inhibition of a miRNA let-7a transferred by recombinant adeno-associated virus 8(rAAV8)on a xenobiotic-induced mouse model of sclerosing cholangitis.METHODS A xenobiotic-induced mouse model of sclerosing cholangitis was induced by 0.1% 3,5-Diethoxycarbonyl-1,4-Dihydrocollidine(DDC)feeding for 2 wk or 6 wk.A single dose of rAAV8-mediated anti-let-7a-5p sponges or scramble control was injected in vivo into mice onset of DDC feeding.Upon sacrifice,the liver and the serum were collected from each mouse.The hepatobiliary injuries,hepatic inflammation and fibrosis were evaluated.The targets of let-7a-5p and downstream molecule NF-κB were detected using Western blot.RESULTS rAAV8-mediated anti-let-7a-5p sponges can depress the expression of let-7a-5p in mice after DDC feeding for 2 wk or 6 wk.The reduced expression of let-7a-5p can alleviate hepato-biliary injuries indicated by serum markers,and prevent the proliferation of cholangiocytes and biliary fibrosis.Furthermore,inhibition of let-7a mediated by rAAV8 can increase the expression of potential target molecules such as suppressor of cytokine signaling 1 and Dectin1,which consequently inhibit of NF-κB-mediated hepatic inflammation.CONCLUSION Our study demonstrates that a rAAV8 vector designed for liver-specific inhibition of let-7a-5p can potently ameliorate symptoms in a xenobiotic-induced mouse model of sclerosing cholangitis,which provides a possible clinical translation of PSC of human.
基金Supported by Tianjin Health Research Project,No.TJWJ2023MS062。
文摘BACKGROUND Dry eye syndrome(DES)after diabetic cataract surgery can seriously affect the patient’s quality of life.Therefore,effective alleviation of symptoms in patients with this disease has important clinical significance.AIM To explore the clinical effect of recombinant human epidermal growth factor(rhEGF)plus sodium hyaluronate(SH)eye drops on DES after cataract surgery in patients with diabetes.METHODS We retrospectively evaluated 82 patients with diabetes who experienced DES after cataract surgery at Tianjin Beichen Hospital,Affiliated Hospital of Nankai University between April 2021 and April 2023.They were classified into an observation group(42 cases,rhEGF+SH eye drops)and a control group(40 cases,SH eye drops alone),depending on the different treatment schemes.The therapeutic efficacy,dry eye symptom score,tear film breakup time(TFBUT),basic tear secretion score[assessed using Schirmer I test(SIt)],corneal fluorescein staining(FL)score,tear inflammatory markers,adverse reactions during treat-ment,and treatment satisfaction were compared between the two groups.RESULTS Therapeutic efficacy was higher in the observation group compared with the control group.Both groups showed improved TFBUT and dry eye,as well as improved SIt and FL scores after treatment,with a more pronounced improvement in the observation group.Although no marked differences in adverse reactions were observed between the two groups,treatment satisfaction was higher in the observation group.CONCLUSION rhEGF+SH eye drops rendered clinical benefits to patients by effectively ameliorating dry eye and visual impairment with favorable efficacy,fewer adverse reactions,and high safety levels.Thus,this treatment should be promoted in clinical practice.
文摘The multi-factor recombination and processes superimposition model for hydrocarbon accumulation is put forward in view of the hydrocarbon geological characteristics of multiple episodes of structural evolution, multiple sets of source-reservoir-seal assemblage, multiple cycles of hydrocarbon accumulation and multiple episodes of readjustment and reconstruction in the complex superimposed basins in China. It is a system including theories and methods that can help to predict favorable exploration regions. According to this model, the basic discipline for hydrocarbon generation, evolution and distribution in the superimposed basins can be summarized in multi-factor recombination, processes superimposition, multiple stages of oil filling and latest stage preservation. With the Silurian of the Tarim basin as an example, based on the reconstruction of the evolution history of the four factors (paleo-anticline, source rock, regional cap rock and kinematic equilibrium belt) controlling hydrocarbon accumulation, this model was adopted to predict favorable hydrocarbon accumulation areas and favorable exploration regions following structural destruction in three stages of oil filling, to provide guidance for further exploration ofoil and gas in the Silurian of the Tarim basin.
基金supported by the National Institutes of Health of the United States (U24CA143835)the Blanton-Davis Ovarian Cancer Research Program+2 种基金the Asian Foundation for Cancer Research to W.Zsupported by grants from the National Natural Science Foundation of China (#81101673, #81472761 to G.L.)Tianjin Science and Technology Committee Foundation (14JCYBJC25300 to G.L. and 14RCGFSY00148 to F.X.)
文摘Ovarian carcinoma is the most lethal gynecologic malignancy. Resistance to platinum is considered the major problem afecting prognosis. Our recent study established that micro RNA-506(mi R-506) expression was closely associated with progression-free survival and overall survival in two independent patient cohorts totaling 598 epithelial ovarian cancer cases. Further functional study demonstrated that mi R-506 could augment the response to cisplatin and olaparib through targeting RAD51 and suppressing homologous recombination in a panel of ovarian cancer cell lines. Systemic delivery of mi R-506 in an orthotopic ovarian cancer mouse model signiicantly augmented the cisplatin response, thus recapitulating the clinical observation. Therefore, mi R-506 plays a functionally important role in homologous recombination and has important therapeutic value for sensitizing cancer cells to chemotherapy, especially in chemo-resistant patients with attenuated expression of mi R-506.
文摘Infertility is a common problem that affects approximately 15% of the population. Although many advances have been made in the treatment of infertility, the molecular and genetic causes of male infertility remain largely elusive. This review will present a summary of our current knowledge on the genetic origin of male infertility and the key events of male meiosis. It focuses on chromosome synapsis and meiotic recombination and the problems that arise when errors in these processes occur, specifically meiotic arrest and chromosome aneuploidy, the leading cause of pregnancy loss in humans. In addition, meiosis-specific candidate genes will be discussed, including a discussion on why we have been largely unsuccessful at identifying disease-causing mutations in infertile men. Finally clinical applications of sperm aneuploidy screening will be touched upon along with future prospective clinical tests to better characterize male infertility in a move towards personalized medicine.
基金Supported by the National Major Science and Technology Projects,No.96-901-01-54.
文摘INTRODUCTIONHelicobacter pylori (H . pylori) is associated with the development of chronic gastritis ,peptic ulcer and gastric cancer and gastric MALT lymphoma[1-9],H .pylori has many antigens ,including urease ,heat shock protein and vacuolating cytotoxin and so on ,and urease is an important factor in the colinization of the gastric mucosa and suspected to cause damage to the gastric mucosa[10-14].At the same time ,urdase is also one of the important protective antigens .
基金supported by the National Natural Science Foundation of China(39870499)funded by the Nationa1 Outstanding Youth Foundations from National Natural Science Foundation of China(30125032).
文摘The transgenic tobacco plants transformed with movement protein gene of Tomato mosaic virus (ToMV) or Tobacco mosaic virus (TMV) and partial replicase gene of Cucumber mosaic virus (CMV) P1 isolate (CMV-P1), were inoculated with Potato virus X, Potato virus Y, TMV and CMV isolate RB (CMV-RB), respectively. Symptom observation showed there were no symptom differences in transgenic tobacco plants as compared with those in non-transgenie tobacco plants. ELISA also illustrated that the virus concentrations in the transgenic plants were similar to those in non-transgenic plants, indicating that no synergism is found in these plants. The transgenic tobacco plants expressing movement protein gene of ToMV or partial replicase gene of CMV-P1 were inoculated with TMV and CMV-RB, respectively. The local or systemic infected leaves were then used for elucidation of the possible virus recombination in transgenic plants with biological infectivity test, ELISA and immuno-capture RT-PCR. Within 16 months, no recombination was found between transformed genes and inoculated virus genomes. The research provides fundamental data for understanding of the possible risk of the transgenic plants expressing viral sequences.
基金Project supported by the National Basic Research Program of China (Grant No. 2006CB202604)the Knowledge Innovation Program of Chinese Academy of Sciences (Grant No. 1KGCX2-YW-383-1)the National High Technology Research and Development Program of China (Grant No. SQ2010AA0521758001)
文摘A new tunnel recombination junction is fabricated for n-i-p type micromorph tandem solar cells. We insert a thin heavily doped hydrogenated amorphous silicon (a-Si:H) p^+ recombination layer between the n a-Si:H and the p hydrogenated nanocrystalline silicon (nc-Si:H) layers to improve the performance of the n-i-p tandem solar cells. The effects of the boron doping gas ratio and the deposition time of the p-a-Si:H recombination layer on the tunnel recombination junctions have been investigated. The current-voltage characteristic of the tunnel recombination junction shows a nearly ohmic characteristic, and the resistance of the tunnel recombination junction can be as low as 1.5 Ω-cm^2 by using the optimized p-a-Si:H recombination layer. We obtain tandem solar cells with open circuit voltage Voc = 1.4 V, which is nearly the sum of the Vocs of the two corresponding single cells, indicating no Voc losses at the tunnel recombination junction.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.10676025 and 10976019)
文摘The KLL dielectronic recombination (DR) processes of ions from highly charged helium-like to oxygen-like krypton, iodine and barium ions are studied systematically in the relativistic distorted-wave approximation with configuration interaction. The KLL DR resonant energies, the corresponding resonant strengths and the theoretical spectra for each highly charged ion species are obtained. The results accord well with other available values. The behaviour of KLL resonant strengths for He-like ions with atomic number Z is analysed.
基金Project supported by the State Key Development Program for Basic Research of China (Grant Nos 2006CB202602 and2006CB202603)the National Natural Science Foundation of China (Grant No 60506003)
文摘This paper reports that a double N layer (a-Si:H/μc-Si:H) is used to substitute the single microcrystalline silicon n layer (n-μc-Si:H) in n/p tunnel recombination junction between subcells in a-Si:H/μc-Si:H tandem solar cells. The electrical transport and optical properties of these tunnel recombination junctions are investigated by current voltage measurement and transmission measurement. The new n/p tunnel recombination junction shows a better ohmic contact. In addition, the n/p interface is exposed to the air to examine the effect of oxidation on the tunnel recombination junction performance. The open circuit voltage and FF of a-Si:H/μc-Si:H tandem solar cell are all improved and the current leakage of the subcells can be effectively prevented efficiently when the new n/p junction is implemented as tunnel recombination junction.