|
|
|
题名
|
作者
|
年代
|
出处
|
被引量
|
| 1 | Discriminated sgRNAs-Based SurroGate System Greatly Enhances the Screening Efficiency of Plant Base-Edited Cells显示文摘The development of CRISPR/Cas9-mediated base editing has made genomic modification more efficient. However, selection of genetically modified cells from millions of treated cells, especially plant cells, is still challenging. In this study, an efficient surrogate reporter system based on a defective hygromycin resistance gene was established in rice to enrich base-edited cells. After step-by-step optimization, the Discriminated sgRNAs-based SurroGate system (DisSUGs) was established by artificially differentiating the editing abilities of a wild-type single guide RNA (sgRNA) targeting the surrogate reporter gene and an enhanced sgRNA targeting endogenous sites. The DisSUGs enhanced the efficiency of screening base-edited cells by 3- to 5-fold for a PmCDA1-based cytosine-to-tyrosine base editor (PCBE), and 2.5- to 6.5-fold for an adenine base editor (ABE) at endogenous targets. These targets showed editing efficiencies of <25% in the conventional systems. The DisSUGs greatly enhanced the frequency of homozygous substitutions and expanded the activity window slightly for both a PCBE and an ABE. Analyses of the total number of single-nucleotide variants from whole-genome sequencing revealed that, compared with the no-enrichment PCBE strategy, the DisSUGs did not alter the frequency of genome-wide sgRNA-independent off-target mutations, but slightly increased the frequency of target-dependent off-target mutations. Collectively, the DisSUGs developed in this study greatly enhances the efficiency of screening plant base-edited cells and will be a useful system in future applications. | Wen Xu Yongxing Yang Ya Liu Guiting Kang Feipeng Wang Lu Li Xinxin Lv Si Zhao Shuang Yuan Jinling Song Ying Wu Feng Feng Xiaoqing He Chengwei Zhang Wei Song Jiuran Zhao Jinxiao Yang | 2020 | Molecular Plant2020，13，1： | 8 |
| 2 | Killing effects of cytosine deaminase gene mediated by adenovirus vector on human pancreatic cancer cell lines in vitro显示文摘OBJECTIVE: To evaluate the killing effects of the cytosine deaminase (CD) gene mediated byadenovirus vector on human pancreatic cancer cell lines in vitro.METHODS: The CD gene was cloned into pAdTrack-CMV-CD, and pAdTrack-CMV-CD and pAdEasy-lwere recombinated in bacteria. The newly recombinated Ad-CD containing green fluoreseent protein(GFP) was propagated in 293 cells and purified by cesium chloride gradient centrifugation. Humanpancreatic cancer cell lines Patu8988 and SW1990 were infected with this virus, then 5-FC was added.XTT assay was used to estimate relative numbers of viable cells.RESULTS: The positive clones were selected by using endonuclease to digest the combinatants and theconcentration of viral liquids containing the CD gene was 2×1O11 pfu/ml. It was found that significantcytotoxic activities were possesscd by 5-FC for the CD gene transduced pancreatic cell lines, but littleeffects exerted on the nontransduced pancreatic carcinoma cells.CONCLUSIONS: The CD gene mediated by adenovirus with a high infectivity is efficient for genetherapy of pancreatic carcinoma cell lines. These data demonstrate the therapeutic efficacy of an enzymeprodrug strategy in experimental pancreatic cancer. | Zhao-Shen Li Xue Pan Guo-Ming Xu Long Cui Guan-Rong Dai Yan-Fang Gong Zhen-Xing Tu the Department of Gastroenterology Department of General Surgery Changhai Hospital, Second Military Medical University, Shanghai 200433, China | 2003 | Hepatobiliary & Pancreatic Diseases International2003，2，1： | 5 |
| 3 | 恢复connexin26表达联合载酵母菌胞嘧啶脱氨酶自杀基因纳泡杀灭膀胱癌细胞显示文摘目的分析载双基因的阳离子纳泡联合超声靶向微泡破坏技术进行基因转染的有效性,探索恢复或上调膀胱癌细胞的缝隙连接蛋白connexin26(Cx26)表达,能否增强自杀基因系统(yeast cytosine deaminase/5-fluorocytosine,YCD/5-FC)的旁观者效应,提高杀灭肿瘤细胞的效率。方法阳离子纳泡结合超声辐照(US)转染人膀胱癌T24细胞,荧光显微镜及流式细胞仪观测转染效率;qRT-PCR和Western blot检测质粒转染后的mRNA或蛋白相对表达量。将实验分为无处理空白对照、载pc DNA3.1-EGFP纳泡组、载Cx26纳泡组、载YCD纳泡组、载YCD+Cx26纳泡组;通过流式细胞术观察恢复Cx26表达后对膀胱癌细胞凋亡的影响。结果 qRT-PCR、Western blot显示纳泡结合超声辐照成功将目的基因转染并有效表达。恢复Cx26表达后,载YCD+Cx26纳泡组的细胞凋亡率为(60.68±2.61)%,明显高于单载YCD纳泡组的(46.42±2.13)%,差异有统计学意义(P<0.01)。结论恢复缝隙连接蛋白Cx26表达,可改善细胞间通讯连接,加强自杀基因系统YCD/5-FC的旁观者效应,促进肿瘤细胞凋亡,提高杀灭膀胱癌细胞的效率。 | 陈思乡 姜庆 张俊勇 | 2018 | 第三军医大学学报2018，40，4： | 3 |
| 4 | New cytosine base editor for plant genome editing显示文摘A large number of beneficial agronomic traits in crops are associated with single nucleotide polymorphisms(SNPs)or point mutations(Jiao et al.,2010;Li et al.,2017;Ma et al.,2015).In the past,site-specific point mutations in a target gene can only be achieved through the CRISPR/Cas9 mediated gene replacement via the homology-directed repair(HDR).However,the intrinsically low HDR activity in plant cells and the lack of efficient way to supply abundant HDR templates in plant nucleus have greatly limited the success rate of gene replacement in plants(Ran et al.,2017).In addition,DNA double-strand breaks(DSBs)generated by the Cas9 nuclease prior to HDR may lead to complicated and unexpected genome disturbance(Kosicki et al.,2018). | Zhenxiang Li Xiangyu Xiong Jian-Feng Li | 2018 | Science China(Life Sciences)2018，61，12： | 2 |
| 5 | EFFECTS OF ANTITUMOR DRUGS ON LIPOSOME MEMBRANE PERMEABILITY WITH SPIN LABEL REDUCTIONAL KINETIC BY ASCORBATE显示文摘We have studied the effects of antitumor drugs, thioproline (THIPRO), cytosine (CYTO), actinomycin (ACTI) and 5-fluorine-2’-deoxyuridine (5-F-U), on the membrane fluidity of normal lung cell V79 and cancer lung cell V79-B1 of the Chinese ham- | 赵保路 瞿保钧 张建中 忻文娟 | 1984 | Chinese Science Bulletin1984，29，9： | 1 |
| 6 | IS HYPOMETHYLATION OF CELLULAR DNA A STEP REQUIRED IN THE INITIATION PROCESS OF CHEMICAL CARCINOGENESIS显示文摘The level of DNA methylation in carcinogen treat-ed cells were determined by HpaII restriction frag-ment length analysis of the newly replicated DNAslabelled with H-TdR 24 hr prior to harvesting aswell as by direct HPLC measurement of the 5-methyl-cytosine(~mC)contents of the cellular DNAs. | | 1991 | 癌变.畸变.突变1991，3，S1： | 1 |
| 7 | Microenvironmental control of photochemica reactions Ⅱ.Fluorescence quenching of naphthalene and 1,3-di-(a-naphthyl)propane by RNA and bases in aqueous methanol显示文摘The fluorescence quenching of naphthalene (2)and 1, 3-di(α-naphthyl)propane (1) by RNAand bases in methanol-water (v:v=1:1) binary solvents in the presence or absence of cyclodex-trin (CD) has been investigated. The results show that both the monomer and excimer fluorescenceof 1 can be quenched by these quenchers. The quenching and rates depend on the quencher and tem-perature. It is shown that there is a critical temperature (Tc) for each quencher. Below Tc, the excimerfluorescence spectra show vibrational structures and the Stern-Volmer plots are straight lines (for ura-cil and cytosine); while above the Tc, the vibrational structures disappear and the Stern-Volmer plotsdeviate from linearity and curve upward. The former is a static process; while the latter is a mixtureof both static and dynamic processes. The addition of α-CD has no effect on the fine structure,whereas β-CD prevents the appearance of this structure efficiently. The quenching rates both for themonomer and excimer of 1 by bases except cytosine in the presence of β-CD at ambient temperatureare not changed; the quenching of fluorescence of 1 by RNA in the presence of β-CD, however, ishindered. Time-resolved fluorescence study shows that the excimer fine structures appear from thezero time. The intensity of fine structures depend on the fraction of water (φ) in binary solvents, andit is independent of the pH value of the solvents. It is suggested that bases and RNA induced aggregates(perhaps microcrystal) are formed, in which the motion of molecules 1 is limited. | LEI, Xue-Gong XIE, Rui-Qiang LIU, You-Cheng Department of Chemistry, Lanzhou University, Lanzhou 730000 | 1990 | Chinese Journal of Chemistry1990，8，4： | 0 |
| 8 | Facile Synthesis of a Novel Bio-Based P-N Containing Flame Retardant for Effectively Reducing the Fire Hazards of Epoxy Resin显示文摘In this work,a bio-based flame retardant(Cy-HEDP)was synthesized from cytosine and HEDP through a facile salt-forming reaction and embedded into epoxy matrix to improve the flame retardancy and smoke suppression performance.The product Cy-HEDP was well characterized by FTIR,^(1)H and^(31)P NMR and SEM tests.On the basis of the results,by adding 15 wt%Cy-HEDP,the EP15 can pass UL-94 V-0 rating,and the total smoke production(TSP)as well as total heat release(THR)can be decreased by 61.05%(from 22.61 to 8.7 m^(2)/m^(2))and 39.44%(from 103.19 to 62.50 MJ/m^(2))in comparison to the unfilled EP,reflecting the attenuated smoke toxicity and impeded heat generation.According to the analysis results of residual char,it can be concluded that Cy-HEDP possessed the ability to promote the formation of continuous and dense char layers,which would be a physical barrier to insulate oxygen and prevent heat feedback during the combustion of EP.This work provide inspiration towards developing bio-based flame retardant,probably extending the prospects to other polymeric material system. | Meixian Li Xin Hu Jie Yang Hongyu Yang Yao Yuan | 2022 | Journal of Renewable Materials2022，10，10： | 0 |
| 9 | Speciation-induced heritable cytosine methylation changes in polyploid wheat | 刘宝 胡波 董玉柱 刘振兰 何孟元 | 2000 | Progress in Natural Science:Materials International2000，10，8： | 0 |
| 10 | A Novel Achievement of Pulse Radiolysis of Cytosine Aqueous Solution显示文摘1 Introduction Radiation-inducde direct damage of DNA originates primarily from the electron-gaining and losing sites. Determining the chemical nature and distribution of these sites is obviously a central problem in this field. At present, the most widely accepted model is T^-/G^+ dichotomy model, i. e. electrons are mainly trapped at thymine (T) and holes at guanine (G) through electron transfer along DNA chain. However, recent work showed another possible electron-gaining center: cytosine. In the mean time, the role of proton transfer in affecting the distribution of electron trapping among the DNA bases has received more | 骆坚 王文锋 马先勇 姚思德 张加山 林念芸 | 1993 | Chinese Science Bulletin1993，38，19： | 0 |
| 11 | Gene therapy for malignant melanoma using bacterial cytosine deaminase gene under the control of tyrosinase promoter显示文摘Objective To clone tyrosinase gene promoter and evaluate the role of the promoter in malignantmelanoma cell--specific prodrug activation gene therapy. Methods: PCR was employed to clone murine tyrosinase gene promoter from genomic DNA of B16 cells. Mutation of the promoter was analyzed by DNA scquencing. The promoter was then utilized to direct bacterial cytosine deaminase (CD) gene in a retroviral vector. In vitro gene expression and in vivo gene therapy were carried out. Results: Sequence of tyrosinase genepromoter from B16 cells showed a 98. 7 % homology to that from normal cells. The tyrosinase gene promoterconferred a selective expression of CD gene in B16 cells in vitro. The in situ produced retroviruses containingtyrosinase gene promoter drived CD gene were capable of infecting tumor cells and bone marrow cells inC57BL/6 mice. The Bl6 established tumor significantly regressed following 5-fluorocytosine (5-FC) systemicadministration. The in vivo gene therapy, unlike long terminal repeat (LTR ) universal promoter directed CDgene, did not lead to the arrest of bone marrow. Conclusion: CD gene directed by the tyrosinase gene promoters, either from melanorna cells or from normal cells, is effective and safe for the melanoma in vivo genetherapy. | 曹广文 戚中田 潘欣 张晓琴 高军 崔龙 杜平 | 1998 | Journal of Medical Colleges of PLA(China)1998，13，3： | 0 |
| 12 | UV-INDUCED BASE CHANGE MUTATION SPECTRA IN A SHUTTLE VECTOR PLASMID PROPAGATED IN CELLS FROM XERODERMA PIGMENTOSUM COMPLEMENTATION GROUPS A,C AND F.显示文摘To assess the contribution to mutagenesis byhuman DNA repair defects,UV-irradiated shuttlevector plasmid,pZ189,was passed throughfibroblasts derived from xeroderma pigmentosum(XP)patients in DNA repair complementation groups A,Cand F.In comparison to results with DNA repairproficient human cells,UV-irradiated pZ189 | TakashiYagi MayumiSato JunkoTatsumi-Miyajima KennethH.Kraemer HirakuTakebe | 1991 | 癌变.畸变.突变1991，3，S1： | 0 |
| 13 | No consistent daily variation in DNA methylation detected in Populus nigra leaves by methylation-sensitive amplification polymorphism analysis显示文摘DNA methylation, an epigenetic mechanism used by cells to control gene expression, has an important biological role in plant development and environmental fitness. Since plant DNA methylation is closely related to environmental conditions, variation during the day is expected. Here, in genetically identical plants of Populus nigra clone N46, DNA methylation changes in leaves over a 24 h period were detected using the methylation-sensitive amplification polymorphism method. The results showed different DNA methylation patterns in mature poplar leaves: not only in individuals at the same time, but also in samples at each of the six time during the day. In addition,night samples had a higher percentage of methylation than in morning samples. However, no statistically significant differences were found among the samples gathered at different times. Similar results were obtained for three other P. nigra clones with different genetic backgrounds.Real time q PCR showed that the DNA methyltransferase genes Pt-MET1 and Pt-SOM1 involved in CG DNA methylation in poplar were stable over a 24 h period in leaves of P. nigra N46 compared with circadian-controlled genes. That could be part of the reason that methylation of CCGG sites is stable in those leaves. That DNA methylation differed even in genetically identical plants indicates the specificity of DNA methylation changes in their genomes. No statistically significant differences in methylation changes were found between day and night, suggesting that DNA methylation is more stable than expected and is unlikely to be involved in circadian regulation in plants. | Shu Diao Yanbo Wang Changjun Ding Yingying Chang Lixiong Liang Yanan Gao Bingyu Zhang Xiaohua Su | 2017 | Journal of Forestry Research2017，28，4： | 0 |
| 14 | Cloning, construction of prokaryotic expression vector and expression of Escherichia coli cytosine deaminase gene显示文摘Cytosine deaminase gene of Escherichia coli strain H30 was cloned, and its initiation codon of ’GTG’ was mutated to ’ATG’ by PCR. Prokaryotic recombinant expression vector pBV220CD was constructed. Clone with high enzyme activity were selected by detecting their specific activity of cytosine deaminase. 5FC(5FC, 5fluorocytosine) could induce the lethal toxicity to cells containing active CD gene. DNA sequence analysis indicated that there were 16 altered bases and 5 of them resulted in the alteration of amino acids in predicted peptide by comparing DNA sequence of the clone H30CD11 with high enzyme activity with CD gene reported in Gene Bank. | Shengjun Ren Huiqiu Jiang Jianren Gu | 1998 | Chinese Science Bulletin1998，43，3： | 0 |
| 15 | Studies on Phosphate Effect of Cytosine and Its Novel Photoproduct显示文摘IntroductionIn1963,MoorA.M.[1]firstlyreportedthephosphateefect,i.e.,intheUVirradiation(253.7nm)ofaqueoussolutionsof4-amino-2-... | LIN Feng(Department of Chemistry, Hangzhou University, Hangzhou, 310028) WANG Wen qing and WU Ji lan (Department of Technical Physics, Peking University, Beijing, 100871) | 1998 | Chemical Research in Chinese Universities1998，14，4： | 0 |
| 16 | Adenovirus-mediated tissue specific cytosine deaminase gene therapy for human hepatocellular carcinoma with different AFP expression level显示文摘Hepatocellular carcinoma (HCC) is one of the mostcommon cancers in the world, especially in East Asia.There is no standardized or effective strategy could beadapted routinely except of some early diagnosedpatients, and the prognosis is poor. In recent years, genetherapy has become a standard experimental approach fortreating cancers that have escaped conventionaltherapies. One such an approach is to confer the tumorcells with sensitivity to chemical reagents through | Hiroaki Wakimoto Hirofumi Hamada | 1997 | 中国实验血液学杂志1997，5，3： | 0 |
| 17 | PtRu nanoparticles supported on noble carbons for ethanol electrooxidation显示文摘In this work,three cytosine derived nitrogen doped carbonaceous materials(noble carbons,NCs)with different atomic C/N ratios and porous networks have been synthesized and used as supports for Pt Ru electrocatalysts in the ethanol oxidation reaction(EOR)for clean hydrogen production.Both,the metal phase and the carbon support play critical roles in the electrocatalysts final performance.Lower NPs size distribution was obtained over supports with low atomic C/N ratios(i.e.,4 and 6)and defined porosity(i.e.,1701 m^(2)g^(-1)for Pt Ru/CNZ and 1834 m^(2)g^(-1)for Pt Ru/CLZ,respectively).In contrast,a lower C/N ratio and poor porous network(i.e.,65 m^(2)g^(-1),Pt Ru/CLK)led to the largest particle size and fostered an increase of the alloying degree between Pt and Ru NPs(i.e.,3%for C/N~6 and 28%for C/N~3).Electrochemical active surface area was found to increase with decreasing NPs size and the alloy extent,due to a higher availability of Pt active sites.Accelerated degradation tests showed that Pt Ru/NCs outperform similar to Pt Ru NPs on commercial carbon pointing at the stabilizing effect of NCs.Pt Ru/CNZ exhibited the best electrochemical performance(i.e.,69.1 m A mgPt-1),outperforming Pt Ru/CLZ and Pt Ru/CLK by3-and 9-fold,respectively,due to a suitable compromise between particle sizes,degree of alloy,textural properties and elemental composition.Best anodes were scaled-up to a proton exchange membrane cell and Pt Ru/CNZ was proved to provide the best electrocatalytic activity(262 m A cm^(-2)and low energy requirements),matching the values obtained by the state of the art of EOR electrocatalysts. | Alberto Rodríguez-Gómez Enrico Lepre Luz Sánchez-Silva Nieves López-Salas Ana Raquel de la Osa | 2022 | Journal of Energy Chemistry2022，31，3： | 0 |
| 18 | ENHANCED ANTITUMOR EFFECTS OF SUICIDE GENE THERAPY BY SIMULTANEOUS TRANSFER OF GMCSF GENE IN LEUKEMIA-BEARING MICE显示文摘ENHANCEDANTITUMOREFFECTSOFSUICIDEGENETHERAPYBYSIMULTANEOUSTRANSFEROFGMCSFGENEINLEUKEMIABEARINGMICE1JuDianwen鞠佃文CaoXuetao2曹雪... | 鞠佃文 曹雪涛 于益芝 陶群 王宝梅 万涛 | 1998 | Chinese Journal of Cancer Research1998，10，2： | 0 |
| 19 | Killing effect of adenoviral mediated cytosine deaminase gene on human pancreatic cancer cell line PaTu8988显示文摘Objective:To evaluatethein vitro killingeffectsof cytosinedeaminasegene mediatedby adenovirusvector on humanpancreaticcarcinoma.Methods:CytosineDeaminase(CD)genewas clonedintopAdTrack-CMV-CD,pAd-Track-CMV-CDandpAdEasy-1wererecombinedinbacteria,andtheproductscontaininggreenfluorescentprotein(GFP)werepropagatedin293cellsandpurifiedby cesiumchloridegradientcentrifugation.Humanpancreaticcarcinomacellline8988wereinfectedwiththisvirus,then5-FCwasadded;XTTassaywasusedto estimatetherelativenumbersof viable cells.Results:Thepositivecloneswereconfirmedby usingendonucleasedigestion,andthetiterof theviruscontaining CD genewas2×10 11 pfu/ml.Itwasfoundthat5-FCpossessedsignificantcytotoxicactivitiesforCD genetransfected8988cellline,buthadlittleeffectson non-transfectedpancreaticcarcinomacells.Conclusion:CD genemediatedby adenovirus hasa highinfectivityandis efficientforkillingculturedpancreaticcarcinomacells,indicatingsuicidegenemaybe effec-tiveforpancreaticcancerinfuture. | 潘雪 李兆申 许国铭 崔龙 张素贞 龚燕芳 屠振兴 | 2001 | Journal of Medical Colleges of PLA(China)2001，16，4： | 0 |
| 20 | Theoretical investigations of collision dynamics of cytosine by low-energy (150-1000 eV) proton impact显示文摘Using a real-space real-time implementation of time-dependent density functional theory coupled to molecular dynamics(TDDFT-MD)nonadiabatically,we theoretically study both static properties and collision process of cytosine by 150-1000 eV proton impact in the microscopic way.The calculated ground state of cytosine accords well with experiments.It is found that proton is scattered in any case in the present study.The bond break of cytosine occurs when the energy loss of proton is larger than 22 eV and the main dissociation pathway of cytosine is the breaks of C1N2 and N8H10.In the range of 150 eV≤Ek≤360 eV,when the incident energy of proton increases,the excitation becomes more violent even though the interaction time is shortened.While in the range of 360 eV | 王志萍 张丰收 许雪芬 钱超义 | 2020 | Chinese Physics B2020，29，2： | 0 |
您所在的机构暂未开通此部分的功能，请联系管理员