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DNA甲基化是一种十分重要的表观遗传修饰,与转座元件沉默、基因组印记以及X染色体失活等多种生物学过程相关。胚胎特异性转录因子的表达可以将已经分化的小鼠(Mus musculus)成纤维细胞重编程为诱导多能干细胞(iPSCs)。由于在重编程过程中还伴随着一系列的表观遗传修饰变化,iPSCs可作为研究表观遗传特点的有利工具,用来研究表观遗传修饰的相互作用及其动态学过程。本研究中,从35 d的猪(Sus scrofa)胎儿分离出胎儿成纤维细胞(PFF),使用经典的4因子组合,即Oct4、Sox2、Klf4和cMyc将PFF重编程为iPSCs,并进行了多能标记的染色,结果表明,所得到的克隆呈现OCT4、SOX2、NANOG和SSEA1阳性结果。采用亚硫酸氢盐测序法对内源性多能性相关基因Oct4、Sox2、Klf4、c-Myc的启动子区域甲基化进行了检测,发现其启动子甲基化程度很低,表明体细胞重编程为iPSCs的过程伴随着多能基因启动子甲基化程度的降低,为理解iPS重编程中多能性相关基因的DNA去甲基化过程和了解控制多能性相关基因的表观遗传调节提供基础。 相似文献
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向分化的体细胞内导入特定的诱导因子,可将其重编程为诱导多潜能干细胞(induced pluripotent stem cells,iPSCs),iPSCs同胚胎干细胞(embryonic stem cells,ESCs)一样具有自我更新并维持未分化状态的能力。iPSCs的出现,有效地解决了ESCs研究领域存在的伦理道德限制和免疫排斥问题。自2006年国际上首次成功获得小鼠(Mus musculus)诱导多潜能干细胞以来,iPSCs研究发展迅猛。从利用病毒载体到普通质粒载体,从导入DNA、RNA和蛋白质,再到利用小分子化合物组合进行体细胞重编程,iPSCs诱导技术正在向多元化发展;同时,研究者们对细胞重编程机理的认识也在加深。与此同时,大家畜iPSCs研究领域也相继获得了猪(Sus scrofa)、牛(Bos taurus)和绵羊(Ovis aries)等动物的iPSCs,并得到了iPSCs嵌合猪和iPSCs嵌合羊。由于猪等大家畜不仅在解剖和生理结构等方面与人相似,还是人类(Homo sapiens)最主要的肉类和奶类等食物来源,关系着人类的健康,因此大家畜iPSCs在临床应用和生产实践上具有重大价值。鉴于此,本文对iPSCs诱导方法、效率、机制和大家畜iPSCs研究现状做一综述。 相似文献
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转录因子nanog和oct-4是细胞具有多潜能性的关键调控因子,一般认为它们的表达是细胞具有多潜能性和自我更新能力的标志.本研究将牛成纤维细胞(BEF422)分别移入GV期和MⅡ期卵母细胞,体外培养24 h后,RT-PCR检测其nanog和oct-4基因的表达情况,并用免疫荧光染色法对这两个基因在移植卵中的分布进行定位.结果表明,牛成纤维细胞移植入GV期和MⅡ期卵母细胞培养后,nanog和oct-4基因均被诱导表达,并且明显定位于移植细胞的细胞核上,而成纤维细胞组和未注射成纤维细胞的空白卵母细胞组中均未检测到nanog和oct-4的表达.说明GV期和MⅡ期卵母细胞均能激活成纤维细胞中转录因子nanog和oct-4的表达,使其发生重编程.本研究选取GV期和MⅡ期这两个关键时期的卵母细胞为研究对象,为进一步解释卵母细胞中含有的与供体细胞重编程相关的物质及作用机理提供了一定的基础资料. 相似文献
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黄甜 《农业生物技术学报》2011,(3)
诱导多能干细胞(iPSCs)是由体细胞经过特定的因子诱导重编程而来,它作为细胞更新的来源在再生医学上有着很大的应用前景。人们普遍认为产生iPSCs的个体不会排斥这种自体同源的细胞,但是它们的免疫原性没有被真正的检测过。美国加州 相似文献
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供体细胞的不完全重编程是克隆动物成功率低的主要原因。本研究旨在探讨组蛋白去乙酰化酶抑制剂Scriptaid对牦牛(Bos grunniens)成纤维细胞重编程的影响,以及Scriptaid处理供体细胞对牦牛-黄牛(Bos taurus)异种核移植(interspecies somatic cell nuclear transfer,iSCNT)胚胎体外发育的影响。分别利用0、500、1000、1500和3000nmol/LScriptaid处理牦牛胎儿成纤维细胞,观察细胞形态、统计细胞活率、测定细胞周期、检测组蛋白乙酰化水平,并以处理后的成纤维细胞进行体细胞核移植,检测重构胚体外发育水平。结果显示,经Scriptaid处理24h后,细胞形态发生了改变,细胞增殖受到明显抑制,大量细胞被阻滞在G0/G1期;随着Scriptaid处理浓度的增加,细胞组蛋白H3K9ac乙酰化水平逐渐提高;以1000nmol/L Scriptaid处理的成纤维细胞作为供体细胞后的囊胚率显著高于其他组(P<0.05)。研究结果表明,Scriptaid能显著提高牦牛成纤维细胞的乙酰化水平,以1000nmol/L Scriptaid处理供体细胞显著提高了牦牛-黄牛异种克隆胚胎的体外发育。本研究初步证实Scriptaid是通过提高成纤维细胞的乙酰化水平来促进核的重编程,为研究供体细胞的重编程以及异种克隆牦牛提供理论依据。 相似文献
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金华猪胎儿成纤维细胞系的建立与生物学特性分析 总被引：2，自引：0，他引：2
建立并保存家畜的成纤维细胞在保护畜禽种质资源研究中发挥着重要作用。本研究以40日龄金华猪胚胎为实验材料,采用组织贴壁法建立了金华猪胎儿成纤维细胞系,并对所建细胞系进行生物学特性研究。结果表明,原代细胞生长迅速,贴壁后2~3d可长满培养瓶,获得的成纤维细胞生长态势良好;细胞生长曲线为典型的S形,细胞群体倍增时间(population doubling time,PDT)约为36h;细胞冻存前、复苏后的活率分别为95.2%和92.8%;细胞中期染色体二倍体(2n=38)占主体约为91%,达到了建立成纤维细胞系的要求;苹果酸脱氢同工酶(malic dehydrogenase,MDH)和乳酸脱氢同工酶(lactic dehydrogenase,LDH)电泳结果表明,本细胞系没有被其他细胞污染,细胞纯度较高;细菌、真菌和支原体三类微生物检测结果均为阴性,细胞没有受到微生物的污染;15代细胞的凋亡率为2.0%,细胞没有大规模的凋亡现象发生;当阳离子脂质体(Lipofectamine2000)剂量为0.3μL、荧光蛋白报告质粒(pEGFP-N3)为0.5μg时转染成纤维细胞的效率最高,可达32.4%。细胞系各项指标均达到美国典型培养中心(American Type CultureCollection,ATCC)标准。金华猪胎儿成纤维细胞系的成功建立使金华猪种质资源在细胞水平得到保存,并可为胚胎克隆以及转基因等研究提供必要的实验材料;也可以为以后其他种质资源在细胞水平上的保存提供理论与技术支持。 相似文献
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通过对猪的卵丘细胞和胎儿成纤维细胞的分离、培养和传代的研究,摸索出一套猪体细胞的分离、培养和传代的方法,建立了猪的供体细胞系。研究结果表明:猪的卵丘细胞单层的生长需要5~6 d;运用组织块法和酶消化法获得胎儿成纤维细胞,组织块法单层的生长需要10~11 d,酶消化法需要8~9 d。猪的卵丘细胞和胎儿成纤维细胞均可以建立并获得稳定的细胞系,这些供体细胞培养方法的应用可为猪体细胞核移植研究提供丰富的供体细胞材料来源。 相似文献
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Identification of oxidation products of (-)-epigallocatechin gallate and (-)-epigallocatechin with H(2)O(2) 总被引：4，自引：0，他引：4
Zhu N Huang TC Yu Y LaVoie EJ Yang CS Ho CT 《Journal of agricultural and food chemistry》2000,48(4):979-981
(-)-Epigallocatechin gallate (EGCG) and (-)-epigallocatechin (EGC) are two important antioxidants in tea. They also display some antitumor activities, and these activities are believed to be mainly due to their antioxidative effects. However, the specific mechanisms of antioxidant action of tea catechins remain unclear. In this study are isolated and identified two novel reaction products of EGCG and one product of EGC when they were reacted separately with H(2)O(2). These products are formed by the oxidation and decarboxylation of the A ring in the catechin molecule. This study provides unequivocal proof that the A ring of EGCG and EGC may also be an antioxidant site. This study also indicates an additional reaction pathway for the oxidation chemistry of tea catechins. 相似文献
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W R Dantzer J Hopper K Mullin S Hendrich P A Murphy 《Journal of agricultural and food chemistry》1999,47(10):4291-4296
14C-Fumonisin B(1) (FB(1)) was produced by Fusarium proliferatum M-5991 in modified Myro liquid medium and purified to >95% purity with a specific activity of 1.7 mCi/mmol. Nine male and nine female F344/N rats were each dosed by gavage with 0.69 micromol of (14)C-FB(1), (14)C-hydrolyzed FB(1), or (14)C-FB(1)-fructose/kg body weight. Urinary excretion of (14)C-FB(1) and (14)C-FB(1)-fructose was 0.5% and 4.4% of the total dose, respectively, and was similar between male and female rats. Urinary excretion of (14)C-hydrolyzed HFB(1) was significantly greater (P > 0.05) in female rats as compared with male rats (17.3% vs 12.8% of the total dose, respectively). There were no significant (P > 0.05) differences in biliary excretion of the three fumonisin compounds with a mean of 1. 4% of the dose excreted at 4 h after dosing. Lesser amounts continued to be excreted up to 9.25 h after dosing. Although biliary excretion of the (14)C-FB(1), (14)C-hydrolyzed FB(1), and (14)C-FB(1)-fructose was similar, increased urinary excretion of the (14)C-hydrolyzed FB(1) as compared to (14)C-FB(1) and (14)C-FB(1)-fructose indicated a greater absorption of the hydrolyzed form. 相似文献
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Roy A 《Journal of agricultural and food chemistry》1999,47(12):5209-5210
Terpinolene oxide, a monoterpene belonging to the p-menthane group, is easily derived from naturally abundant (R)-limonene. It was isomerized with montmorillonite clay catalyst to karahanaenone (2,2, 5-trimethylcyclohept-4-en-1-one) by ring enlargement. The enantiomers of the corresponding alcohol, karahanaenol (2,2, 5-trimethylcyclohept-4-en-1- ol), known for their individual organoleptic properties, were resolved through Pseudomonas cepacia lipase mediated enantiospecific alcoholysis of its acetate derivative. 相似文献
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The presence of ethylenediamine-N-(o-hydroxyphenylacetic)-N'-(p-hydroxyphenylacetic) acid (o,p-EDDHA) as the second largest component in commercial EDDHA iron chelates has recently been demonstrated. Here is reported the speciation of o,p-EDDHA by the application of a novel methodology through the determination of the complexing capacity, protonation, and Ca(2+), Mg(2+), Cu(2+), and Fe(3+) stability constants. The pM values and species distribution in solution, hydroponic, and soil conditions were obtained. Due to the para position of one phenol group in o,p-EDDHA, the protonation constants and Ca and Mg stability constants have different values from those of o,o-EDDHA and p,p-EDDHA regioisomers. o,p-EDDHA/Fe(3+) stability constants are higher than those of EDTA/Fe(3+) but lower than those of o,o-EDDHA/Fe(3+). The sequence obtained for pFe is o,o-EDDHA/Fe(3+) >/= o,p-EDDHA/Fe(3+) > EDTA/Fe(3+). o,p-EDDHA/Fe(3+) can be used as an iron chelate in hydroponic conditions. Also, it can be used in soils with limited Cu availability. 相似文献
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S. R. Verma J. P. S. Arora J. S. Shankar R. Chand 《Water, air, and soil pollution》1987,36(3-4):247-257
The effect of protein oxovanadium(V) ion concentration and pH on the ratio of diffusion current (id/id0) was studied in vanadium(V) ovalbumin-S and denatured ovalbumin systems. In both the cases marked decrease in diffusion current was observed at the respective pH values, indicating that binding takes place with cationic groups of the proteins. The binding sites (n) were found to be pH dependent. The uniformity of logK and ΔG 0 value at all pH values indicated the involvement of same sites in interaction. Furthermore, the linear scatchard plots in both the systems supported the involvement of single class of independent sites in oxovanadium(V) anion interaction. The difference in binding sites (n) has been attributed to the folded structure of ovalbumin-S while unfolded one of denatured ovalbumin. 相似文献
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The efficiency of As(III) oxidation by MnO2, and retention of oxidation products varies with system pH. Maximum retention by hydrous Mn(IV) oxide occurs at pH < 5, declining at higher pH to about half total As at pH 10. The adsorption capacities of pyrolusite and cryptomelane at pH ～6.5 for As(V) species were 10 and 25 mmol kg?1, respectively. HMO surface saturation (～10 mmol kg?1) was reached with equilibrium As(V) levels of 5 to 8 × 10?6 M but this was supplemented at higher levels by an absorption process where uptake increased linearly with concentration (e.g., 68 mmol kg?1 with 2 × 10?5 M As(V)). Added As(III) was avidly oxidized and most product retained at pH 3. At higher pH increasing amounts of As(III) remained unoxidized due to initial reactions apparently blocking access to internal pores. Added Na+ reduced the amount of As retained by the HMO, with the phosphate salt having a significant effect. Extraction studies confirmed that most As could be released by exposure to reducing agents or chelating agents (EDTA). The environmental significance of the results has been considered. 相似文献