期刊文献+
共找到297篇文章
< 1 2 15 >
每页显示 20 50 100
Creation of cytochrome P450 catalysis depending on a non-natural cofactor for fatty acid hydroxylation
1
作者 Qing Li Xiaojia Guo +4 位作者 Xueying Wang Junting Wang Li Wan Haizhao Xue Zongbao K.Zhao 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第4期31-36,共6页
Cytochrome P450 enzymes catalyze diverse oxidative transformations at the expense of reduced nicotinamide adenine dinucleotide phosphate(NADPH),however,their applications remain limited largely because NADPH is cost-p... Cytochrome P450 enzymes catalyze diverse oxidative transformations at the expense of reduced nicotinamide adenine dinucleotide phosphate(NADPH),however,their applications remain limited largely because NADPH is cost-prohibitive for biocatalysis at scale yet tightly regulated in host cells.A highly challenging task for P450 catalysis has been to develop an alternative and biocompatible electrondonating system.Here we engineered P450 BM3 to favor reduced nicotinamide cytosine dinucleotide(NCDH)and created non-natural cofactor-dependent P450 catalysis.Two outstanding mutants were identified with over 640-fold NCDH preference improvement and good catalytic efficiencies of over15,000 M^(-1)s^(-1)for the oxidation of the fatty acid probe 12-(para-nitrophenoxy)-dodecanoate.Molecular docking analysis indicated that these mutants bear a compacted cofactor entrance.Upon fusing with an NCD-dependent formate dehydrogenase,fused proteins functioned as NCDH-specific P450catalysts by using formate as the electron donor.Importantly,these mutants and fusions catalyzed NCDH-dependent hydroxylation of fatty acids with similar chain length preference to those by natural P450 BM3 in the presence of NADPH and also similar regioselectivity for subterminal hydroxylation of lauric acid.As P450 BM3 and its variants are catalytically powerful to take diverse substrates and convey different reaction paths,our results offer an exciting opportunity to devise advanced cell factories that convey oxidative biocatalysis with an orthogonal reducing power supply system. 展开更多
关键词 Biocatalysis Cytochrome P450 Directed evolution Fatty acid hydroxylation Non-natural cofactor Synthetic biology
下载PDF
PEO/Cofactor助留体系应用于ONP/OMG脱墨浆生产纸材料 被引量:4
2
作者 刘全校 张勇 +1 位作者 曹国荣 许文才 《包装工程》 CAS CSCD 北大核心 2006年第4期65-67,70,共4页
介绍了PEO/Cofactor助留体系应用于ONP/OMG脱墨浆生产纸材料。实验结果表明:PEO/Cofactor助留体系对以ONP/OMG脱墨浆为主要纤维原料的助留作用效果良好,并可有效控制浆料中的树脂。脱墨浆中的水溶性杂质和非离子性表面活性剂不利于PEO/C... 介绍了PEO/Cofactor助留体系应用于ONP/OMG脱墨浆生产纸材料。实验结果表明:PEO/Cofactor助留体系对以ONP/OMG脱墨浆为主要纤维原料的助留作用效果良好,并可有效控制浆料中的树脂。脱墨浆中的水溶性杂质和非离子性表面活性剂不利于PEO/Cofactor助留体系的作用效果的发挥;PEO/Cofactor助留体系与阳离子壳聚糖共用时,效果更好。PEO/Cofactor助留体系对细小组分的留着没有选择性。 展开更多
关键词 PEO/cofactor助留体系 ONP/OMG脱墨浆 纸材料
下载PDF
PEO/Cofactor助留助滤体系的絮凝特性及机理 被引量:2
3
作者 王祥民 何北海 钱丽颖 《中国造纸学报》 CAS CSCD 北大核心 2003年第2期129-132,共4页
介绍了聚环氧乙烷 (PEO)的溶解热力学动平衡过程对PEO溶液特性的影响以及PEO用作助留剂的絮凝机理。PEO在吸附时 ,分子链的熵的损失会减弱PEO的吸附能力 ,损失过大时 ,会阻止PEO进行吸附。PEO经CF(Cofactor)改性的过程使得热函增加 ,当... 介绍了聚环氧乙烷 (PEO)的溶解热力学动平衡过程对PEO溶液特性的影响以及PEO用作助留剂的絮凝机理。PEO在吸附时 ,分子链的熵的损失会减弱PEO的吸附能力 ,损失过大时 ,会阻止PEO进行吸附。PEO经CF(Cofactor)改性的过程使得热函增加 ,当增加量超过损失值时 ,会促进PEO吸附。不同的CF对PEO进行改性的程度是不一致的 。 展开更多
关键词 PEO 助留助滤 助留剂 溶解热 聚环氧乙烷 改性 用具 分子链 吸附 机理
下载PDF
固氮酶活性中心FeMo-Cofactor对N_2活化方式的探讨 被引量:1
4
作者 张纯喜 樊红军 刘秋田 《化学进展》 SCIE CAS CSCD 1997年第3期265-272,共8页
结合实验和理论计算的结果,讨论了固氮酶的活性中心铁钼辅基(FeMo-co-factor)对N2的各种活化方式,并在此基础上提出了一种新模型,即N2在FeMo-cofactor的内部以“4Fe端基配位+2Fe侧基配位”... 结合实验和理论计算的结果,讨论了固氮酶的活性中心铁钼辅基(FeMo-co-factor)对N2的各种活化方式,并在此基础上提出了一种新模型,即N2在FeMo-cofactor的内部以“4Fe端基配位+2Fe侧基配位”的方式被活化,N2的三重键完全断裂,断裂产生的两个含N的碎片分别偏向两侧的“窗口”,再在H的进攻下被还原为NH3,并分别从两侧的“窗口”离去。 展开更多
关键词 固氮酶 铁钼辅基 活化模型 氮分子 活性中心
下载PDF
Studies on Chem icalCom position ofIron-m olybdenum Cofactor fromNitrogenase by Fluorescence Analysis
5
作者 ZHANG Feng-zhang XU Liang-shu +3 位作者 HUANG He-qing LONG Min-nan QIU Xue-hui CHEN Zhong 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 1999年第3期286-293,共8页
The iron molybdenum cofactor(FeMoco) of nitrogenase MoFe protein from Azotobacter vinelandii OP was extracted by N methylformamide(NMF). The effects of FeMoco(in NMF) on electronic spectrum and fluorescence... The iron molybdenum cofactor(FeMoco) of nitrogenase MoFe protein from Azotobacter vinelandii OP was extracted by N methylformamide(NMF). The effects of FeMoco(in NMF) on electronic spectrum and fluorescence intensity of fluorescein dimercury acetate(FDMA)(in 1 mol/L NaOH) were investigated by fluorophotometric titrations and compared with those of (NH 4) 2MoS 4 and complexes of (NH 4) 2MoS 4 with Na 2S or Na 2S 2 or (NH 4) 2S x on the relative properties of FDMA. It was found that the electronic spectrum of FDMA displayed hypsochromic shift(17 nm) in the presence of FeMoco just like that in the presence of other inorganic sulfides and that the titration curve for the quench of FDMA with FeMoco is very similar to that for the quench of FDMA with complex of (NH 4) 2MoS 4 with Na 2S 2(mole ratio is 1∶3). The results showed that FeMoco(N) probably contained S—S bonds and its structure was found to be changed compared with Kim Rees structural model. This change should profit the formation of the polymer. 展开更多
关键词 NITROGENASE Iron molybdenum cofactor Fluorophotometric titration Structural change
下载PDF
DECOMPOSITION THEOREM AND k-HYPERCONNECTION EXPRESSIONS FOR GENERAL k-ORDER COFACTORS
6
作者 黄汝激 《Journal of Electronics(China)》 1991年第4期307-316,共10页
Two k-hyperconnection expressions of a general k-order cofactor Y<sub>(i,j)</sub> are presentedfor the indefinite parameter matrix Y of a linear system by applying directed hypergraph theory,and based on... Two k-hyperconnection expressions of a general k-order cofactor Y<sub>(i,j)</sub> are presentedfor the indefinite parameter matrix Y of a linear system by applying directed hypergraph theory,and based on it a decomposition theorem of Y<sub>(i,j)</sub> is derived.By this theorem,the multi-leveltearing and analysis can be carried out easily for any linear large system.This is a new mul-tilevel topological analysis method.Using proposed method the scale of systems which can betopologically analysed by a computer will be enlarged. 展开更多
关键词 Directed hypergrsph theory k-Order cofactor k-Hyperconnection MULTILEVEL TOPOLOGICAL analysis
下载PDF
Study of Cofactors Associated with Precancerous High-Grade Cervical Lesions at the Teaching Hospital Gabriel Touré, 2010 to 2015
7
作者 Fané Seydou Bocoum Amadou +8 位作者 Sissoko Abdoulaye Traoré Soumana Oumar Sanogo Siaka Amara Mamadou Sima Kouma Aminata Traoré Alassane Tegueté Ibrahima Traoré Youssouf Mounkoro Niani 《Surgical Science》 2019年第9期328-337,共10页
Introduction: High grade dysplasia of the cervix has a high incidence and can progress to cervical cancer. The aim was to study cofactors associated with high-grade cervical dysplasia. Methodology: This was a retrospe... Introduction: High grade dysplasia of the cervix has a high incidence and can progress to cervical cancer. The aim was to study cofactors associated with high-grade cervical dysplasia. Methodology: This was a retrospective case-control study without matching. Women with high grade dysplasia were the cases while those with a normal screening test represented the controls. The study took place at the Gabriel Touré University Hospital Center in Bamako. We included 351 cases and 420 controls. The capture and analysis were performed using the SPSS 20 software. A univariate and multivariate logistic regression analysis was performed for the analysis of risk cofactors. The statistical tests used were the odds ratio and its confidence interval and the statistical significance threshold was set at p Results: In univariate analysis, the co-factors statistically significantly associated with the occurrence of high-grade dysplasia were parity 0.6 (0.5 - 0.9), gestational 0.7 (0.5 - 0.9), smoking of the spouse 3.4 (1.1 - 11.3), the non-schooling 1.4 (1.2 - 2.1). In multivariate analysis after adjusting for confounding factors, two co-factors have significantly increased the risk of high-grade dysplasia: lack of schooling 1.4 (1.2 - 2.0) and polygamy 1.5 (1.4 - 2.5). Conclusion: At the end of this study, polygamy and lack of schooling were the main risk factors. The prevention of cervical cancer will go through the education of girls and women as well as communication for behavioral change and social change. 展开更多
关键词 High Grade Dysplasia cofactor Cervical Cancer Teaching Hospital GABRIEL Touré
下载PDF
The roles of tubulin-folding cofactors in neuronal morphogenesis and disease
8
作者 Misako Okumura Masayuki Miura Takahiro Chihara 《Neural Regeneration Research》 SCIE CAS CSCD 2015年第9期1388-1389,共2页
Microtubules play important roles in neuronal morphogenesis, including cellular polarization, neurite growth, and branching. A microtubule is a polymer of a- and β-tubulin heterodimers that are formed by a multistep ... Microtubules play important roles in neuronal morphogenesis, including cellular polarization, neurite growth, and branching. A microtubule is a polymer of a- and β-tubulin heterodimers that are formed by a multistep process assisted by at least five tubulin-fold- ing cofactors (TBCA-E) (Lopez-Fanarraga et al., 2001). Newly syn- thesized α- and β-tubulins associate with the cytosolic chaperonin complex (CCT), and then the quasi-native tubulins interact with five tubulin-folding cofactors. The α- and β-tubulins first interact with TBCB and TBCA, which are further transferred to TBCE and TBCD, respectively. The α- and β-tubulins, TBCC, TBCD, and TBCE form a supercomplex, and guanosine triphosphate (GTP) hydrolysis occurs within the supercomplex, releasing a tubulin heterodimer. In addition to their functions in tubulin folding and tubulin heterodimer formation, excess amounts of TBCD or TBCE may interact with tubulin heterodimers, leading to their degrada- tion. Thus, tubulin-folding cofactors may play a role in both the synthesis and degradation of tubulin heterodimers. 展开更多
关键词 The roles of tubulin-folding cofactors in neuronal morphogenesis and disease Figure
下载PDF
Factors Affecting Fines Flocculation Performance with Cofactor-Polyethylene Oxide
9
作者 M. R. Abdallah Qasaimeh Ahmad Qasaimeh F. Bani Hani 《Advances in Chemical Engineering and Science》 2014年第1期49-55,共7页
In literature, neutral polyethylene oxide (PEO) flocculated fines at low shear rates, while with cofactor (CF) addition, the formed CF-PEO complex showed larger ability to bridge fines, producing flocs. In this work, ... In literature, neutral polyethylene oxide (PEO) flocculated fines at low shear rates, while with cofactor (CF) addition, the formed CF-PEO complex showed larger ability to bridge fines, producing flocs. In this work, some process factors were found having significant effects on fines flocculation. Increases in CF to PEO ratio at constant PEO enhanced the bridging bonds, causing increases in flocculation initial rate (efficiency), amplitude (floc size), and fastness (a decrease in characteristic time). On the other hand, an increase in stirring rate (shear rate) in flocculation vessel caused decreases in initial rate and amplitude, and an increase in the fastness. All runs showed transient flocculation;the amplitude increased with time, reached maximum at equilibrium, and then started to decrease showing deflocculation. In brief, the CF to PEO ratio and the shear rate were found important parameters in mill operation, having significant effects on flocculation efficiency, fastness, and floc size. 展开更多
关键词 POLYETHYLENE Oxide cofactor FLOCCULATION SHEARING and BRIDGING
下载PDF
Iron overload and cofactors with special reference to alcohol,hepatitis C virus infection and steatosis/insulin resistance 被引量:4
10
作者 Yutaka Kohgo Katsuya Ikuta +2 位作者 Takaaki Ohtake Yoshihiro Torimoto Junji Kato 《World Journal of Gastroenterology》 SCIE CAS CSCD 2007年第35期4699-4706,共8页
有几个余因子,影响身体铁新陈代谢并且加速铁超载。酒精和肝的病毒的感染是为在铁超载澄清余因子的角色的最典型的例子。处于这些条件,铁在房间和通过 Fenton 反应生产的反应的氧种类(ROS ) 有的 hepatocytes 和 Kupffer 被扔便于 tra... 有几个余因子,影响身体铁新陈代谢并且加速铁超载。酒精和肝的病毒的感染是为在铁超载澄清余因子的角色的最典型的例子。处于这些条件,铁在房间和通过 Fenton 反应生产的反应的氧种类(ROS ) 有的 hepatocytes 和 Kupffer 被扔便于 transferrin 固定的铁的细胞的举起的关键角色。而且, hepcidin,主要在肝生产的抗菌剂肽为肠的铁吸收和网状内皮组织的铁版本也负责。在有血浆铜蓝蛋白缺乏的病人,在肝和 neurodegeneration 的贫血症和第二等的铁超载被报导。而且,正在积累没有酒精和肥胖的脂肪酸累积自己修改铁超载状态的证据。无效红血球生成也是一个重要因素加速铁超载,它与象地中海贫血和 myelodysplastic 症候群那样的疾病被联系。当这个条件坚持时,饮食的铁吸收由于骨髓红血球生成的增长被增加,织物铁超载愿望此后发生。在迟发性皮肤卟啉症,铁是在肝积累的在第二。 展开更多
关键词 铁超负荷 慢性肝炎 非酒精性脂肪肝 胰岛素抵抗 肝癌
下载PDF
Identification of positive cofactor 4 as a diagnostic and prognostic biomarker associated with immune infiltration in hepatocellular carcinoma
11
作者 Liangliang Bai Guan Liu +5 位作者 Gang Dou Xiaojun He Chenyu Gong Hongbin Zhang Kai Tan Xilin Du 《iLIVER》 2023年第4期188-201,共14页
Background and aims:Human positive cofactor 4(PC4)is associated with the development and therapeutic resistance of several malignancies.However,the role of PC4 in hepatocellular carcinoma(HCC)remains obscure.Methods:T... Background and aims:Human positive cofactor 4(PC4)is associated with the development and therapeutic resistance of several malignancies.However,the role of PC4 in hepatocellular carcinoma(HCC)remains obscure.Methods:The expression status of PC4 was explored in Gene Expression Omnibus and The Cancer Genome Atlas datasets.Subsequently,the prognostic and diagnostic significance of PC4 in HCC patients was analyzed.Functional enrichment analyses were conducted to explore biological functions and potential mechanisms.The CIBERSORT algorithm was used for immune infiltration analysis.The risk signature was constructed by LASSO-Cox regression and was validated with the International Cancer Genome Consortium dataset.Quantitative real-time polymerase chain reaction was used to verify the expression levels of all genes.Tumor Immune Dysfunction and Exclusion analysis evaluated immunotherapy response.Finally,using online databases,PC4-related competing endogenous RNA networks were constructed.Results:PC4 levels were significantly upregulated in HCC and positively correlated with the pathological grade and clinical stage.The PC4-high expression group showed worse prognosis.In addition,PC4 could distinguish between tumor and normal tissues with an area under the curve of 0.965.The PC4 level was associated with immune checkpoints and immune cell infiltration.In the training and validation sets,the eight-gene risk signature strongly correlated with HCC patient prognosis.Tumor Immune Dysfunction and Exclusion analysis showed that patients in both the PC4-low and low-risk groups were more likely to benefit from immunotherapy.Finally,an lncRNA/microRNA-101-3p/PC4 network was constructed.Conclusion:We confirmed PC4 as a diagnostic and prognostic biomarker in HCC patients.We also developed and validated an eight-gene risk signature,which will help in clinical decision-making.The competing endogenous RNA network could help explore the regulatory mechanisms of PC4 in HCC. 展开更多
关键词 Hepatocellular carcinomaHuman positive cofactor 4 Prognosis Risk signature
原文传递
卤代甲基转移酶的发现与应用研究进展
12
作者 陈琦 张诗雨 +2 位作者 高春玉 郑高伟 许建和 《华东理工大学学报(自然科学版)》 CAS CSCD 北大核心 2024年第1期1-3,共3页
近年来,甲基化反应在有机合成和生物合成领域中逐渐引起重视。通过甲基转移酶(MT)引入甲基基团,可以调控分子的生物活性和物理化学性质,为精准设计目标分子的结构和功能提供了新的途径。卤代甲基转移酶(HMT)是一类特殊的MT,它不仅可以... 近年来,甲基化反应在有机合成和生物合成领域中逐渐引起重视。通过甲基转移酶(MT)引入甲基基团,可以调控分子的生物活性和物理化学性质,为精准设计目标分子的结构和功能提供了新的途径。卤代甲基转移酶(HMT)是一类特殊的MT,它不仅可以催化产生各种卤代烃,还可以在碘甲烷等廉价非天然甲基供体的存在下实现昂贵辅因子S-腺苷甲硫氨酸(SAM)的酶促原位再生。通过HMT的分子改造和同系酶的基因挖掘,可以高效地催化合成或再生SAM及其类似物,为甲基及其他烷基的转移提供更简单的路线。本文主要介绍了HMT的最新研究进展及其突破性工作:通过引入HMT-MT双酶级联反应,创建简单通用的SAM循环再生系统,提高了反应的原子经济性;挖掘到来源于硫嘌呤甲基转移酶家族的新酶(TPMT),很好地解决了甲基供体的环保问题;利用定向进化技术获得HMT优势突变体,能成功实现更长链烷基的转移。这些创新研究为高效生物烷基化提供了新策略,为绿色生物制造带来潜在的技术变革。 展开更多
关键词 卤代甲基转移酶 辅因子原位再生 S-腺苷甲硫氨酸 蛋白质工程 酶促级联反应
下载PDF
结直肠癌组织miR-331-3p、MLLT10 mRNA表达变化及其临床意义
13
作者 王健 窦宗山 +1 位作者 王娟 徐靖 《山东医药》 CAS 2024年第1期6-10,共5页
目的观察结直肠癌(CRC)组织微小RNA-331-3p(miR-331-3p)、混合谱系白血病转位辅因子10(MLLT10)mRNA表达变化,并探讨其表达与临床病理特征和上皮间质转化的关系。方法选择CRC患者156例,取术中获取的CRC组织及其配对的癌旁正常组织,采用... 目的观察结直肠癌(CRC)组织微小RNA-331-3p(miR-331-3p)、混合谱系白血病转位辅因子10(MLLT10)mRNA表达变化,并探讨其表达与临床病理特征和上皮间质转化的关系。方法选择CRC患者156例,取术中获取的CRC组织及其配对的癌旁正常组织,采用实时荧光定量聚合酶链反应检测miR-331-3p、MLLT10mRNA表达以及上皮间质转化相关基因E-钙黏蛋白(E-cadherin)、N-钙黏蛋白(N-cadherin)、锌指转录因子Snail mRNA表达。比较CRC组织与癌旁正常组织miR-331-3p及MLLT10、E-cadherin、N-cadherin、Snail mRNA表达;分析CRC组织miR-331-3p、MLLT10 mRNA表达与临床病理特征的关系,二者表达的关系及其与E-cadherin、N-cadherin、Snail mRNA表达的关系。结果CRC组织MLLT10、N-cadherin、Snail mRNA相对表达量均高于癌旁正常组织,miR-331-3p、E-cadherin mRNA相对表达量均低于癌旁正常组织(P均<0.01)。CRC组织miR-331-3p、MLLT10 mRNA表达与TNM分期、淋巴结转移有关(P均<0.05),而与性别、年龄、肿瘤最大径、肿瘤位置、组织分化程度无关(P均>0.05)。Pearson相关分析显示,CRC组织miR-331-3p表达与MLLT10 mRNA表达呈负相关(r=-0.678,P<0.05);CRC组织miR-331-3p表达与E-cadherin mRNA表达呈正相关(r=0.589,P<0.05),与N-cadherin、Snail mRNA表达呈负相关(r分别为-0.712、-0.654,P均<0.05);CRC组织MLLT10 mRNA表达与E-cadherin mRNA表达呈负相关(r=-0.549,P<0.05),与N-cadherin、Snail mRNA表达呈正相关(r分别为0.668、0.714,P均<0.05)。结论CRC组织miR-331-3p低表达、MLLT10 mRNA高表达,二者表达与TNM分期、淋巴结转移以及上皮间质转化密切相关。 展开更多
关键词 结直肠癌 微小RNA-331-3p 混合谱系白血病转位辅因子10 上皮间质转化
下载PDF
NEW PROOF OF DIMENSION FORMULA OF SPLINE SPACES OVER T-MESHES VIA SMOOTHING COFACTORS 被引量:5
14
作者 Zhang-jin Huang Jian-song Deng Yu-yu Feng Fa-lai Chen 《Journal of Computational Mathematics》 SCIE EI CSCD 2006年第4期501-514,共14页
A T-mesh is basically a rectangular grid that allows T-junctions. Recently, Deng etal introduced splines over T-meshes, which are generalizations of T-splines invented by Sederberg etal, and proposed a dimension formu... A T-mesh is basically a rectangular grid that allows T-junctions. Recently, Deng etal introduced splines over T-meshes, which are generalizations of T-splines invented by Sederberg etal, and proposed a dimension formula based on the B-net method. In this paper, we derive an equivalent dimension formula in a different form with the smoothing cofactor method. 展开更多
关键词 Spline space T-mesh Smoothing cofactors.
原文传递
Engineering Escherichia coli to improve tryptophan production via genetic manipulation of precursor and cofactor pathways 被引量:6
15
作者 Zhu Li Dongqin Ding +4 位作者 Huiying Wang Linxia Liu Huan Fang Tao Chen Dawei Zhang 《Synthetic and Systems Biotechnology》 SCIE 2020年第3期200-205,共6页
Optimizing the supply of biosynthetic precursors and cofactors is usually an effective metabolic strategy to improve the production of target compounds.Here,the combination of optimizing precursor synthesis and balanc... Optimizing the supply of biosynthetic precursors and cofactors is usually an effective metabolic strategy to improve the production of target compounds.Here,the combination of optimizing precursor synthesis and balancing cofactor metabolism was adopted to improve tryptophan production in Escherichia coli.First,glutamine synthesis was improved by expressing heterologous glutamine synthetase from Bacillus subtilis and Bacillus megaterium in the engineered Escherichia coli strain KW001,resulting in the best candidate strain TS-1.Then icd and gdhA were overexpressed in TS-1,which led to the accumulation of 1.060 g/L tryptophan.Subsequently,one more copy of prs was introduced on the chromosome to increase the flux of 5-phospho-α-D-ribose 1-diphosphate followed by the expression of mutated serA and thrA to increase the precursor supply of serine,resulting in the accumulation of 1.380 g/L tryptophan.Finally,to maintain cofactor balance,sthA and pntAB,encoding transhydrogenase,were overexpressed.With sufficient amounts of precursors and balanced cofactors,the engineered strain could produce 1.710 g/L tryptophan after 48 h of shake-flask fermentation,which was 2.76-times higher than the titer of the parent strain.Taken together,our results demonstrate that the combination of optimizing precursor supply and regulating cofactor metabolism is an effective approach for high-level production of tryptophan.Similar strategies could be applied to the production of other amino acids or related derivatives. 展开更多
关键词 Escherichia coli TRYPTOPHAN Metabolic precursors cofactor supply
原文传递
Interplay between cofactors and transcription factors in hematopoiesis and hematological malignancies 被引量:1
16
作者 Zi Wang Pan Wang +4 位作者 Yanan Li Hongling Peng Yu Zhu Narla Mohandas Jing Liu 《Signal Transduction and Targeted Therapy》 SCIE CSCD 2021年第2期409-424,共16页
Hematopoiesis requires finely tuned regulation of gene expression at each stage of development.The regulation of gene transcription involves not only individual transcription factors(TFs)but also transcription complex... Hematopoiesis requires finely tuned regulation of gene expression at each stage of development.The regulation of gene transcription involves not only individual transcription factors(TFs)but also transcription complexes(TCs)composed of transcription factor(s)and multisubunit cofactors.In their normal compositions,TCs orchestrate lineage-specific patterns of gene expression and ensure the production of the correct proportions of individual cell lineages during hematopoiesis.The integration of posttranslational and conformational modifcations in the chromatin landscape,nucleosomes,histones and interacting components via the cofactor-TF interplay is critical to optimal TF activity.Mutations or translocations of cofactor genes are expected to alter cofactor-TF interactions,which may be causative for the pathogenesis of various hematologic disorders.Blocking TF oncogenic activity in hematologic disorders through targeting cofactors in aberrant complexes has been an exciting therapeutic strategy.In this review,we summarize the current knowledge regarding the models and functions of cofactor-TF interplay in physiological hematopoiesis and highlight their implications in the etiology of hematological malignancies.This review presents a deep insight into the physiological and pathological implications of transcription machinery in the blood system. 展开更多
关键词 HEMATOPOIESIS cofactor LANDSCAPE
原文传递
辅酶类核开关的种类、结构和调控机制研究进展
17
作者 许笑晨 任艾明 《自然杂志》 CAS 2024年第2期105-116,共12页
核开关是一类保守的RNA元件,可以通过特异性识别小分子配体来开启或关闭下游相关基因的表达,进而调控细胞的生命活动。目前已鉴定出近60种核开关,它们分别识别不同的代谢物或小分子配体。随着这些核开关的发现,它们的序列特征、高级结... 核开关是一类保守的RNA元件,可以通过特异性识别小分子配体来开启或关闭下游相关基因的表达,进而调控细胞的生命活动。目前已鉴定出近60种核开关,它们分别识别不同的代谢物或小分子配体。随着这些核开关的发现,它们的序列特征、高级结构以及调控机制逐渐成为核开关领域的研究热点。截至目前,大部分核开关的三维结构已经被解析,相关研究不仅阐明了这些核开关对配体的特异性识别方式,还从分子层面阐释了其对下游基因表达的调控机制,为开发核开关相关应用提供了重要的研究基础。文章综述了目前已鉴定的核开关的种类和主要功能,详细探讨了辅酶类核开关的三维空间结构和配体识别机制,并展望了核开关的研究前景及潜在应用。 展开更多
关键词 非编码RNA 核开关 辅酶 三维结构 小分子药物
下载PDF
Targeting host cofactors to inhibit viral infection
18
作者 Stephen FRAUSTO Emily LEE Hengli TANG 《Frontiers of physics》 SCIE CSCD 2012年第5期445-458,共14页
The majority of FDA-approved drugs indicated for the treatment of viral infections are inhibitors of viral proteins, of which the emergence of resistant strains is a major concern. This issue is exacerbated as most de... The majority of FDA-approved drugs indicated for the treatment of viral infections are inhibitors of viral proteins, of which the emergence of resistant strains is a major concern. This issue is exacerbated as most developed antiviral therapies are indicated for the treatment of viruses with error-prone replication. These problems may be addressed by the development of drugs that modulate the function of host factors involved in various aspects of a viral life cycle. Targeting host factors uncouples the mutation of a druggable protein gene from the replication and survival selection pressure exerted on a virus. Currently, a host-targeting antiviral (HTA), maraviroc, is approved for the treatment of human immunodeficiency virus (HIV) infection. In addition, several HTAs indicated for the treatment of hepatitis C virus (HCV) or HIV infection are at various stages of clinical evaluation. Targeting host factors is an attractive complement to therapies directly targeting a viral protein because of the expected higher genetic barrier for resistance and an overall increase in the diversity of treatment options. We examine how the integrated roles of emerging host cofactor screening approaches and drug development strategies may advance current treatment options. 展开更多
关键词 antiviral therapy host-targeting cofactorS drug resistance HIV HCV
原文传递
细胞色素氧化酶P4502C19基因多态检测联合血清肝素辅助因子Ⅱ对下肢动脉硬化闭塞症介入术后再狭窄的预测价值
19
作者 张毅 刘林波 +1 位作者 廖智杰 张恒 《血管与腔内血管外科杂志》 2023年第8期950-955,共6页
目的探讨细胞色素氧化酶P4502C19(CYP2C19)基因多态检测联合血清肝素辅助因子Ⅱ(HCⅡ)对下肢动脉硬化闭塞症(ASO)介入术后再狭窄的预测价值。方法收集2017年1月至2021年5月于绵阳市第三人民医院行介入治疗的146例ASO患者的临床资料,根... 目的探讨细胞色素氧化酶P4502C19(CYP2C19)基因多态检测联合血清肝素辅助因子Ⅱ(HCⅡ)对下肢动脉硬化闭塞症(ASO)介入术后再狭窄的预测价值。方法收集2017年1月至2021年5月于绵阳市第三人民医院行介入治疗的146例ASO患者的临床资料,根据随访期间再狭窄发生情况将其分为再狭窄组(n=27)和无再狭窄组(n=119)。收集患者性别、年龄、体重指数(BMI)、吸烟史、心脑血管病史、高同型半胱氨酸病史、病变血管支数、术前狭窄情况、支架植入情况、纤维蛋白原水平、总胆固醇水平、红细胞计数、CYP2C19基因多态性、HCⅡ活性,分析ASO介入术后再狭窄的影响因素。结果有吸烟史、支架植入、CYP2C19慢代谢型及HCⅡ活性均为ASO支架植入术后发生再狭窄的独立危险因素(P﹤0.05)。受试者工作特征(ROC)曲线结果显示,HCⅡ活性预测ASO支架植入术后再狭窄的截断值为95.80%,曲线下面积(AUC)为0.809(95%CI:0.719~0.900),灵敏度为74.80%,特异度为88.24%,Kappa=0.566。CYP2C19基因多态检测对ASO支架植入术后再狭窄的预测灵敏度为66.67%,特异度为89.07%,Kappa=0.537。联合检测对ASO支架植入术后再狭窄的预测灵敏度为96.30%,特异度为86.55%,Kappa=0.682。结论ASO介入术后再狭窄与吸烟史、支架植入情况、CYP2C19基因多态性及HCⅡ活性有关,CYP2C19基因多态性及HCⅡ活性检测均可用于预测ASO介入术后再狭窄,但联合检测可提高其诊断效能。 展开更多
关键词 细胞色素氧化酶P4502C19 基因多态性 血清肝素辅助因子Ⅱ 下肢动脉硬化闭塞症
下载PDF
行列式按行(列)展开定理的简单证法
20
作者 周仲旺 《高等数学研究》 2023年第2期93-93,共1页
本文利用行列式定义,给出了行列式按行(列)展开定理的一个简单证法.
关键词 行列式 代数余子式 行列式按行(列)展开
下载PDF
上一页 1 2 15 下一页 到第
使用帮助 返回顶部