查询词典 methylation

Tetraploid embryos could be produced by electrofusion at the stage of two-cell embryos, which could develop to blastocysts followed by fusion of cytoplasm and nucleus and cleavage in vitro. During the fusion of cytoplasm, the DNA methylation levels of the fused embryos are as high as these of two-cell diploid embryos in vivo Then the embryos are rapidly demethylated when the nucleus begin to fuse, resulting in the lowest DNA methylation levels when the nucleus are fused completely. After that, the DNA methylation levels of the fused embryos are gradually increased until the morula stage. However, whereas an asymmetric distribution of DNA methylation is established in vivo-derived blastocysts with a higher methylation level in the inner cell mass than that in the trophectoderm, we can not detect the asymmetric distribution in most in vitro-derived tetraploid blastocysts.

结果表明：利用电融合方法制备的小鼠四倍体胚胎在体外培养体系中经历细胞质融合、细胞核融合及细胞继续分裂发育直到囊胚期的过程，在细胞质融合的时候胚胎卵裂球同体内体外培养二倍体胚胎一样，呈现高度甲基化状态；在细胞核开始融合的时候，甲基化水平急速下降，在细胞核完全融合的时候甲基化水平达到最低点；随着胚胎继续分裂，胚胎甲基化水平逐渐增加，在桑葚胚期甲基化水平最高；但是囊胚期四倍体胚胎内细胞团同滋养层细胞甲基化荧光信号没有差别，这与体内体外培养二倍体囊胚内细胞团细胞甲基化荧光强度高于滋养层细胞甲基化荧光强度不同。

Tetraploid embryos could be produced by electrofusion at the stage of two-cell embryos, which could develop to blastocysts followed by fusion of cyto-plasm and nucleus and cleavage in vitro. During the fusion of cytoplasm, the DNA methylation levels of the fused embryos are as high as these of two-cell diploid embryos in vivo Then the embryos are rapidly demethylated when the nucleus begin to fuse, resulting in the lowest DNA methylation levels when the nucleus are fused completely. After that, the DNA methy-lation levels of the fused embryos are gradually increased until the morula stage. However, whereas an asymmetric distribu-tion of DNA methylation is established in vivo-derived blastocysts with a higher methylation level in the inner cell mass than that in the trophectoderm, we can not detect the asymmetric distribution in most in vitro-derived tetraploid blastocysts.

结果表明：利用电融合方法制备的小鼠四倍体胚胎在体外培养体系中经历细胞质融合、细胞核融合及细胞继续分裂发育直到囊胚期的过程，在细胞质融合的时候胚胎卵裂球同体内体外培养二倍体胚胎一样，呈现高度甲基化状态；在细胞核开始融合的时候，甲基化水平急速下降，在细胞核完全融合的时候甲基化水平达到最低点；随着胚胎继续分裂，胚胎甲基化水平逐渐增加，在桑葚胚期甲基化水平最高；但是囊胚期四倍体胚胎内细胞团同滋养层细胞甲基化荧光信号没有差别，这与体内体外培养二倍体囊胚内细胞团细胞甲基化荧光强度高于滋养层细胞甲基化荧光强度不同。

Tetraploid embryos could be produced by electrofusion at the stage of two-cell embryos, which could develop to blastcysts fellowed by fusion of cytoplasm and nucleus and cleavage in vitro.After fusion of cytoplasm, the DNA methylation levels of the fused embryos was very high as well as two-cell diploid embryos in vivo.Then the embryos was rapiddly demethylated when the nucleus begin to fuse, resulting the lowest DNA methylation levels when the nucleus fused completely.After that, the DNA methylation levels of fused embryos were gradually increased until the blastocysts stage.However, whereas an asymmetric distribution of DNA methylation was established in an vivo-derived blastocysts with a higher methylation level in the inner cell mass than in the trophectoderm, in most vitro-derived tetraploid blastocysts, we can not detect the asymmetric distribution.

结果表明：利用电融合方法制备的小鼠四倍体胚胎在体外培养体系中经历细胞质融合、细胞核融合及细胞继续分裂发育直到囊胚期的过程，在细胞质融合的时候胚胎卵裂球同体内体外培养二倍体胚胎一样，呈现高度甲基化状态；在细胞核开始融合的时候，甲基化水平急速下降，在细胞核完全融合的时候甲基化水平达到最低点；随着胚胎继续分裂，胚胎甲基化水平逐渐增加，在囊胚期甲基化水平最高；但是囊胚期四倍体胚胎内细胞团同滋养层细胞甲基化荧光信号没有差别，这与体内体外培养二倍体囊胚内细胞团细胞甲基化荧光强度高于滋养层细胞甲基化荧光强度不同。

Methylation occurs naturally on cytosine bases at CpG sequences and is involved in controlling the correct expression of genes.

Methylation 在 CpG 序列位置的 cytosine 基上自然地发生而且参予控制基因的正确表现。

However, analysis of DNA methylation level indicated that the total DNA methylation levels were not significantly different between diploid and autotetraploid. Autotriploid showed a trend of low DNA methylation level. It implied that the alterations of DNA methylation levels were not linear with the autopolyploidy level in watermelon.

有趣地是，二倍体与四倍体西瓜相比DNA甲基化水准却未发生大规模的调整，而三倍体西瓜显示出较为明显的低DNA甲基化水准趋势，表明西瓜同源多倍化过程中其基因组DNA甲基化水准变化与其倍性不成线性关系。

Significant differences in cytosine methylation level among the three tissues and the same changing tendency in two inbred lines were detected. Both MSAP (methylation sensitive amplification polymorphism) ratio and full methylation level were the highest in bracteal leaf, and the lowest in tassel.

结果表明，3个组织甲基化水平存在一定差异，并在两自交系中表现出相同的变化趋势，即雌穗苞叶的甲基化敏感扩增多态性比率和全甲基化率最高，穗位叶次之，雄穗最低。

Although the biological significance of DNA methylation has been recognized to some extent, the mechanisms of DNA methylation regulation and of the establishment of tissue-specific DNA methylation pattern in somatic cells are still unclear, since the knowledge of the enzymes responsible for de novo DNA methylation and demethylation of DNA is very limited and up to now only two functional DNA methyltransferases in mammals have been cloned.

目前，虽然对DNA甲基化的作用已有一定认识，但DNA甲基化的调节以及发育过程中组织特异的DNA甲基化谱的建立机制还不清楚。问题主要在于对催化重新甲基化和去甲基化反应的酶的了解很少。至今仅克隆出两种有功能的哺乳动物DNA甲基转移酶。

The decisive influencing factor of viscosity in carboxyl-methylation was cross-linking reaction. Carboxyl-methylation was the main influencing factor of solubility and swelling capacity in modification of high content amylose starch. The structure and gelatinization property of different amylose content were analyzed with an Olympus Vanox BHS-2 multi-function optic microscope, and the results were as follows. The structure of ordinary cornstarch was different from the high amylose; gelatinization temperature and pH value of starch were affected deeply by amylose content, but had little difference between the gelatinization of high content amylose starch contained 50% and 70% amylose; pH value had much more effect than temperature on the gelatinization of high content amylose cross-linked starch. Monochloroacetic acid consumption, alcohol concentration and pH value influenced the starch carboxyl-methylation. When alcohol concentration was 60%, pH value 10, monochloroacetic acid/starch mass ratio 55%, the carboxyl-methylation of high amylose cross-linked cornstarch had the best result. With the In-Vitro digestibility model and biodegradation experiment, the digestibility and biodegradability of high amylose cornstarch and its modified starch were detected.

采用Brabande粘度测定仪和Olympus Vanox BHS-2型多功能光学显微镜等分析手段对链淀粉含量50％和70％的高链玉米淀粉及其交联和交联羧甲基化淀粉的结构和性质进行了表征和分析，结果表明，普通玉米淀粉结构与含链淀粉50％和70％高链玉米淀粉结构不同；高链淀粉比普通淀粉难糊化，高链改性淀粉糊化受pH值影响较大，受温度影响较小；淀粉的冻融稳定性、透光率、溶解度、膨胀度和粘度受链淀粉的含量和改性的影响，但是，链淀粉含量超过50％时，则链淀粉含量对淀粉的膨胀度和溶解度影响不大；改性淀粉性质的影响因素中，影响粘度主要因素是交联反应，影响透明度、溶解度和膨胀度主要因素是羧甲基化改性；一氯乙酸用量、反应时乙醇浓度及碱性条件都会影响高链淀粉及其交联淀粉的羧甲基化改性效果，制备羧甲基化改性淀粉的最佳工艺是在pH值为10的60％的乙醇浓度介质中按一氯乙酸/淀粉质量比为55％进行取代反应。

Methylation analysis showed there were different levels of methylation in Zizania latifolia, but high level of methylation in rice

甲基化分析表明，反转座酶序列在菰中有不同程度的甲基化，但在水稻中均为高度甲基化。

Methods genomic dna was extracted from different stages of malignant transformation and tumorigenicity in inoculated athymic mouse 16hbe cells induced by cadmium chloride and methylating status of genome p16 gene promoter was observed with methylation-specific pcr and then compared with the controls.

从各组cdcl2恶性转化不同阶段及接种裸鼠成瘤的16hbe细胞中提取全基因组dna，采取甲基化特异性pcr法(methylation-specific pcr，msp)检测该基因组p16基因启动子区的甲基化状况，与非转化的16hbe对照细胞进行比较，并用去甲基化因子5-azac (5-aza-2'deoxycytidine)处理有异常甲基化的细胞。

This one mode pays close attention to network credence foundation of the businessman very much.

这一模式非常关注商人的网络信用基础。

Cell morphology of bacterial ghost of Pasteurella multocida was observed by scanning electron microscopy and inactivation ratio was estimated by CFU analysi.

扫描电镜观察多杀性巴氏杆菌细菌幽灵和菌落形成单位评价遗传灭活率。