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四川边茶提取物对脂肪酸合酶的抑制作用 总被引：2，自引：0，他引：2
四川边茶（康砖）是黑茶的一个主要品种，所含茶多酚与绿茶和红茶不同。本研究利用酶动力学方法测定了边茶萃取物对脂肪酸合酶（Fatty Acid Synthase, FAS, E.C. 2.3.1.85）的抑制作用，近几年研究报道该酶是减肥和抑癌的双重潜在靶点。结果表明，边茶萃取物对FAS有可逆和不可逆抑制双重作用，最佳萃取溶剂为50％的乙醇，在常温下5 h即可达到最佳萃取效果。用开水泡茶的方法经两次浸取可提取出近60％的抑制FAS有效物，比绿茶的浸出效率约高1倍，但需较长的浸泡时间。边茶的新茶对脂肪酸合酶的抑制能力并不强，存放数年的边茶抑制能力最好，其后有所下降，但大部分抑制活性可保持20年以上，而30年以上保存期可能会使抑制能力明显下降。边茶提取物与底物乙酰辅酶A和丙二酸单酰辅酶A的竞争性质都是竞争性与非竞争性的混合型；对FAS中的酮酰还原反应的抑制不明显，这说明酮酰还原酶结构域并不是其主要作用位点；这些和绿茶及红茶都有不同。由实验结果分析边茶中的抑制剂不同于红茶和绿茶，可能是茶多酚中的茶褐素，其抑制能力高于儿茶素而接近茶黄素。这些结果表明边茶在减肥、抑癌等方面可能具有良好的应用前景。 相似文献
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Nitric oxide (NO) a free radical having both cytoprotective as well as tumor promoting agent is formed from l-arginine by converting it to l-citrulline via nitric oxide synthase enzymes. The reaction product of nitric oxide with superoxide generates potent oxidizing
agent, peroxynitrite which is the main mediator of tissue and cellular injury. Peroxynitrite is reactive towards many biomolecules
which includes amino acids, nucleic acid bases; metal containing compounds, etc. NO metabolites may play a key role in mediating
many of the genotoxic/carcinogenic effects as DNA damage, protein or lipid modification, etc. The basic reactions of nitric
oxide can be divided as direct effect of the radical where it alone plays a role in either damaging or protecting the cell
milieu and an indirect effect in which the byproducts of nitric oxide formed by convergence of two independent radical generating
pathways play the role in biological reactions which mainly involve oxidative and nitrosative stress. Nitric oxide is also
capable of directly interacting with mitochondria through inhibition of respiration or by permeability transition. Reaction
of nitric oxide with metal ions include its direct interaction with the metals or with oxo complexes thereby reducing them
to lower valent state. Excessive production of nitric oxide can be studied by inhibiting the synthetic pathway of nitric oxide
using both selective or specific nitric oxide synthase inhibitor or non-selective nitric oxide synthase inhibitor with respect
to isoforms of nitric oxide. 相似文献
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Upendra Yadav Pradeep Kumar Vandana Rai 《Indian journal of clinical biochemistry : IJCB》2021,36(1):23
Methionine synthase reductase (MTRR) is an important enzyme of the folate/homocysteine pathway. It is responsible for regulation of methionine enzyme by reductive methylation. A common variant A66G is reported in the FMN-binding domain of the MTRR gene, which leads to substitution of isoleucine by methionine (I22M) in MTRR enzyme with reduced activity. Reduced catalytic activity of enzyme leads to high homocysteine concentration in blood and increases risk for numerous diseases. The frequency of A66G polymorphism varies in different ethnic groups. The present study has been designed to evaluate the frequency of MTRR A66G gene polymorphism in the Eastern UP population by PCR–RFLP method. Along with this we also performed a meta-analysis to evaluate the global prevalence of this polymorphism. Databases were screened to identified the eligible studies. The prevalence of the G allele and GG genotype was determined by the use of prevalence proportion with 95% CI. Open meta-analyst software was used for the meta-analysis. Total 1000 blood samples were analyzed, the frequencies of A and G alleles were 0.35 and 0.65 respectively. Meta-analysis results revealed that the prevalence of G allele and GG genotype were 49.4% (95% CI 40.6–58.1, p ≤ 0.001) and 24.3% (95% CI 17.8–30.9, p ≤ 0.001) respectively. In sub-group meta-analysis, the lowest frequency of G allele was found in South America (32.7%; 95% CI 14.1–51.3, p ≤ 0.001), and highest in Asia (56.4%; 95% CI 39.5–73.3, p ≤ 0.001). The results of the meta-analysis showed that the Asian population has the highest frequency of G allele and highest frequency of the GG genotype was found in the European population. 相似文献
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目的:探讨胸苷酸合成酶(TS)和雌激素受体(ER)在乳腺癌中的表达及它们的相关性.方法:采用免疫组织化学SP法检测111例乳腺癌和38例乳腺腺瘤组织中TS和ER的表达情况.结果:乳腺腺瘤的TS和ER阳性率分别为10.53%(4/38)和36.84%(14/38),差异有显著性(P<0.05);乳腺癌病人中TS和ER的阳性率分别为31.53%(35/111)和40.54%(45/111),差异无显著性(P>0.05).乳腺癌中TS和ER的表达水平与患者年龄、发生部位、组织学类型、淋巴结转移相关性不明显(P>0.05).TS和ER在乳腺腺瘤组呈正向相关(r=0.077),而在乳腺癌组呈负向相关(r=-0.016).结论:TS在乳腺癌组表达率明显高于腺瘤(P<0.0 5);ER在良、恶性乳腺肿瘤内表达率差异无显著性(P>0.05).检测TS、ER对化疗药物选择有指导意义. 相似文献
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一氧化氮与运动训练 总被引：23，自引：1，他引：22
侯丽 《天津体育学院学报》1999,14(3):13-16
一氧化碳(NO)对人体有广泛的生物学效应,在多个系统的病理生理过程发挥作用。本文阐述了运动训练中NO 的变化及其机制,NO 对骨骼肌血流和氧代谢的调节,NO 对运动训练中冠脉血管的作用,与NO 有关的体育锻炼对血管栓塞性疾病的影响及运动训练对血小板功能的影响 相似文献
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根据GenBank发布的基因序列,设计PCR引物,分别从诸葛菜(Orychophragmus violaceus)的花瓣基因组DNA和cDNA克隆到查尔酮合成酶基因,并定名为OvCHS,序列已上传至NCBI数据库,登陆号为EF408918。序列分析表明,OvCHS基因的基因组全长为1263 bp,具一个75 bp的内含子,编码区全长为1188 bp,编码395个氨基酸。与模式植物拟南芥(Arabidopsis thaliana)查尔酮合成酶基因AtCHS比较发现,两基因编码区有135个碱基不同,相似性为88.64%,氨基酸序列中仅16个氨基酸残基的差异,相似性达95.95%。 相似文献
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测定了药典中106味温热性中药和119味寒凉性中药对脂肪酸合酶的抑制水平,发现温热药中对该酶强抑制的频数高于寒凉药约38%. 进一步分析发现,温热药中的温里和散内寒药中强抑制药的频数大幅提高,而寒凉药中的清热泻火、明目、清虚热药中强抑制药的频数则进一步降低,差异均具有显著性. 综合以上结果提出,直接影响能量代谢系统、造成能量代谢率变化是形成中药的寒热药性的因素之一. 相似文献
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目的：观察中药雪芙蓉胶囊对雄性大鼠力竭游泳时间、血清雄激素水平及伏隔核神经元型一氧化氮合酶（nNOS）表达的影响。方法：将30只雄性成年大鼠随机分为3组,即安静对照组、游泳组、中药游泳组。中药游泳组每天灌服雪芙蓉胶囊（5mg/kg）,28天后测试大鼠力竭游泳时间,检测血清睾酮含量,用免疫组织化学结合图像半定量方法对nNOS神经元的数量、面积及灰度进行测量和分析。结果：与游泳组比较,中药游泳组大鼠的力竭游泳时间延长、血清睾酮增高（P〈0.01,P〈0.05）;nNOS免疫阳性细胞数量和阳性产物面积均减少（P〈0.01）,灰度没有显著差异（P〉0.05）。结论：中药雪芙蓉胶囊可提高大鼠的运动能力,延缓中枢疲劳,机理可能与雪芙蓉胶囊提高游泳大鼠血清睾酮水平,同时减少伏隔核nNOS的过度表达有关。 相似文献
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运动训练对大鼠主动脉一氧化氮合酶及细胞凋亡的影响 总被引：2，自引：4，他引：2
目的:探讨不同强度训练对大鼠主动脉一氧化氮合酶(NOS)及细胞凋亡的影响。方法:采用跑台训练方式,建立大鼠有氧运动和疲劳运动模型,运用免疫组织化学SABC法研究不同运动强度对大鼠主动脉神经型一氧化氮合酶(neuronal nitric oxide synthase,nNOS)、诱导型一氧化氮合酶(in-duced nitric oxide synthase,iNOS)、内皮型一氧化氮合酶(endothelial nitric oxide synthase,eNOS)和细胞凋亡蛋白(Bcl-2/Bax)表达的影响。结果:有氧训练组与对照组比较,主动脉NOS 3个亚型及Bcl-2,Bax表达差异显著(P<0.05);疲劳训练组与对照组和有氧训练组比较,主动脉iNOS、eNOS及Bcl-2,Bax表达差异显著(P<0.05),nNOS虽有增加但差异不显著。结论:运动可引起大鼠主动脉NOS 3个亚型及Bcl-2,Bax表达变化,且与运动强度关系密切。有氧训练可使主动脉NOS适度表达且抑制细胞凋亡,疲劳训练会导致大鼠主动脉iNOS过量表达,细胞发生凋亡现象。因此认为,运动训练引起NOS亚型表达变化与运动诱导的主动脉细胞凋亡关系密切。 相似文献