查询词典 DNA

Appressoria were latent in intercellular cleft and were latent until banana fruit were harvested.The development process of conidia of Colletotrichum musae on fruit was not distinct from foliage and stalk.Two pairs of PCR primers were designed according to the two especial fragment (357bp and 206bp) of Colletotrichum musae. Banana tissue culture seedling genomic DNA, banana anthracnose pathogen genomic DNA, mango anthracnose pathogen genomic DNA, rubber anthracnose pathogen genomic DNA,watermelon anthracnose pathogen genomic DNA, banana crown rot pathogen genomic DNA, stylo anthracnose pathogen genomic DNA, watermelon Fusarium wilt pathogen genomic DNA were extracted using SDS method.

根据香蕉炭疽菌的两个特异片段(分别为357bp和206bp)，设计两对引物：采用SDS法分别提取了香蕉组培苗基因组DNA、香蕉果实炭疽菌弱致病株Z_1基因组DNA、香蕉果实炭疽菌强致病株Z_4基因组DNA、芒果炭疽菌基因组DNA、橡胶炭疽菌基因组DNA、柱花草炭疽菌基因组DNA、西瓜炭疽菌基因组DNA、香蕉冠腐病菌基因组DNA、西瓜枯萎病菌基因组DNA；以上述基因组DNA为模板对特异片段进行PCR验证，证明357bp的片段为Colletotrichum musaes所特有，可以用此片段进行香蕉果实炭疽病的分子检测试验，。

The regulation of gene expression is to have relations to the assembly of the DNA binding proteins which bind to DNA to initiate the transcription. Some of these proteins have the ability to promote bending or looping of DNA. The FIS protein regulates gene expression in Escherichia coli by this property of bending DNA. There are many researches to discover the mechanism of FIS protein binds to DNA. However the experiment data only show the supposititious results and figure out the model of FIS-DNA complex structure. This research uses molecular dynamics simulation to compute the detail of the interaction between FIS and DNA. We observed FIS prominently affects the DNA bending by the type of local bending. Analyzing the DNA structure properties, roll and slide, also demonstrates the local bending type and region. The hydrogen bonds between FIS and DNA are analyzed to compare with the experiment data. Finally we compute the binding free energy between FIS and DNA to estimate the result of simulation and compare with the value of λ-repressor-DNA complex.

基因的表现与结合於DNA促使DNA转录作用起始的DNA结合蛋白组装有关，一些这类的蛋白质具有促使DNA扭曲或将DNA形成环状的能力，FIS蛋白质即是藉由扭曲DNA的特性调控大肠杆菌基因的表现，目前已有很多的研究发现FIS与DNA结合的机转，然而这些实验的数据仅能显示推测性的结果，进而利用这些结果推论出FIS与DNA聚合体结构的模型，本研究利用分子动态模拟的方式计算FIS与DNA交互作用的细节，我们观察到FIS主要影响DNA的扭曲方式为DNA区域扭曲的类型，并且分析DNA结构特性roll与slide也指出扭曲方式为区域扭曲与其扭曲的区域，我们也分析FIS与DNA之间的氢键，并且与实验的资料作比较，最后我们计算FIS与DNA之间的结合自由能评估模拟的结果，并且计算出的值和λ-repressor与DNA聚合体结构的实验值作比较。

Using nuclear DNA C-values for 539 angiosperms in China, we examined the variation of these values among growth forms and taxonomic groups and the relationship of these values with invasiveness. Mean DNA C-value of the 539 angiosperm species was 4.06 pg. Mean DNA C-value was(1) significantly lower for woody species (1.84 pg) than for herbaceous species(5.02 pg);(2) significantly lower for 360 dicots (2.20 pg) than for 179 monocots (7.80 pg);(3) significantly lower for annuals (2.78 pg) than for perennials(6.65 pg);(4) significantly lower for 134 weed species (1.93 pg) than for herbaceous non-weeds (6.75 pg) and for several families that have an unusually high proportion of weed species;(5) significantly lower for 47 exotic weed species (1.76 pg) than for 134 native weeds (1.93 pg), but significantly lower than that of "non-weedy" herbaceous species (6.75 pg);(6) lower for weeds than for "non-weedy" species in same genus or family; and (7) in herbaceous species, generally lower for weedy compared to "non-weedy" species, with some exceptions such as Avena fatua, whose DNA C-value is as high as 14.15 pg, contrarily, and some "non-weedy" herbaceous species in Cruciferae and Cucurbitaceae with very low values.

统计了中国境内有分布的539种被子植物的DNA C-值，分析了它们在不同分类群、生活型、倍性、生活史类型以及在杂草和非杂草类群中的分布情况，主要结果如下：(1)539种被子植物DNA C-值平均为4.06 pg，其中木本植物的DNA C-值平均为1.84 pg，低于草本植物的平均值(5.02 pg)；(2)双子叶植物(360种)的DNA C-值平均为2.20 pg，极明显地小于单子叶植物(179种)的平均值(7.80 pg)；(3)1年生植物的DNA C-值平均为2.78 pg，明显小于多年植物的平均DNA C-值(6.65 pg)；(4)134种杂草的DNA C-值平均为1.93 pg，明显小于非杂草草本植物的平均值(6.75 pg)，含杂草较多的科，平均DNA C-值相对较小；(5)统计的47种入侵杂草的DNA C-值平均为1.76 pg，略小于134种杂草的平均DNA C-值(1.93 pg)，极显著地小于非杂草性草本植物(6.75 pg)；(6)以科为单位，不同科的DNA C-值存在着极大的差异；(7)DNA C-值与染色体倍性的关系并不明显，但是，随着倍性的增加，基因组变小；(8)在同一科、属中，与非杂草相比，典型杂草的DNA C-值往往偏小；(9)总体上杂草或杂草性强的植物，它们的DNA C-值比非杂草性植物的要小。

Since Watson and Crick have brought forward the model of DNA helix structure and explain about it's reproduce mechanism in molecule level, research work concerning DNA has been continuously lucubrated. However, whether translating inheritance information and rebuilding DNA molecule via menstruating DNA sequence, or to date the most compelling gene project, chromosome protract et. al, there all need a sort of molecule scissors cleaving DNA, DNA cleavage reagent. At present, tool enzyme of cleaving DNA is mostly DNA restriction enzymes founded in 70 years, which only cleave DNA at specific 4-8 base pair sequences that are usually palindromic, so this restricts the at very fast speed developing of gene technology at certain extent.

自从Watson和Crick提出DNA的双螺旋结构并对其复制机制在分子水平上进行解释后，使得对DNA的研究不断深入，但无论是通过测定DNA的序列来破译遗传信息、改造DNA分子，还是目前最令人关注的基因工程、染色体绘制等，都需要一种断裂DNA分子的&剪刀&——DNA断裂试剂，目前断裂DNA的工具酶主要是上个世纪70年代发现的DNA限制性内切酶，但所知的Ⅱ型限制性内切酶的DNA序列识别长度较短（约为4～8个碱基对），而且一般要求回文结构，这就给飞速发展的基因工程技术带来一定的限制。

NodD binds to and bends target promoters through anchoring two tandem and individual specific DNA sites. NodD functions as a tetramer, which has a V-shaped main body. Tetrameric NodD is to change its own conformation rather than its oligomeric forms in response to small signal molecules. The specific interaction between each NodD DNA-binding domain and each specific DNA site does not alter itself in spite of naringenin induction, and the induced conformational change is transferred from protein to DNA. Only the DNA conformation incited by induced NodD is competent for RNA polymerase to form the transcriptional open complex. It cannot be excluded that NodD may have protein-to-protein contacts with RNA polymerase, and that the NodD conformational change may also directly contribute to the transcriptional open complex formation. However, the NodD conformational change itself cannot serve as the determinant of the transcriptional molecular switch.

通过研究，我们提出了初步的NodD操纵子激活模型：第一，四聚体是NodD蛋白的功能单位，它通过铆钉两个串联的相对独立的DNA靶位点结合被诱导的启动子；第二，小分子配基的结合是改变NodD四聚体的构象而不是引发不同形式的寡聚体，在我们的模型中，NodD四聚体缩小其V形主体的弯折角，进而缩短其DNA结合功能域的间距；第三，小分子信号的诱导并没有改变NodD的DNA结合域和其DNA靶位点的相互作用，NodD的构象改变由蛋白质经其双铆钉位点传递给DNA；第四，只有诱导状态的NodD激发的DNA构象才能有效地使RNA聚合酶形成转录开放复合物；第五，不排除NodD与RNA聚合酶可能有直接的相互接触位点，不排除NodD构象的改变可能直接有利于RNA聚合酶形成转录开放复合物，但是我们认为NodD构象改变本身不是充当转录激活开关的决定因素。

Extracted DNA by CTAB, in proportion to the additions of PVP and β-mercap toethanol to the extraction buffer were capable of preventing browning from taking place in the extraction, Tris-Phenol (Stabilized with 0.1M Tris, pH 8.0)/Chloroform/isoamyl alcohol were used to remove protein and impurity in the second extraction, during crude DNA used to Isopropanol DNA and deterged by DNA detergent, without using RNase remove RNA, we detected the quality and concentration of DNA respectively for normal leaves and drought stress leaves by Agarose gel electrophoresis of genomic DNA and ultraviolet spectrometry photo.

用20%聚乙二醇(polyethylene glycol，PEG6000)模拟干旱，采取CTAB提取缓冲液，按一定比例加入PVP和β-巯基乙醇，用Tris平衡酚－氯仿－异戊醇除去蛋白质及杂质，在粗提时用异丙醇沉淀DNA，并用DNA洗液（10mmol/L醋酸铵，75%乙醇）洗涤DNA，在纯化时用乙醇沉淀DNA，且没有加入RNase去除RNA的方法，分别提取2个品种正常和干旱胁迫的苹果属叶片总DNA，并对提取的DNA进行琼脂糖凝胶电泳和紫外分光光度计检测。

After process purification DNA needs once more magnetism bead purification processing, the magnetism bead under the specific liquid environment with the DNA adsorption, is fixed under the magnetic field function one side the centrifuge tube, only has DNA and the magnetism bead unifies in the together part is retained, then the use specific elutes the fluid clean, finally uses double steams the water to dissolve DNA, by now the magnetism bead and DNA were separated from, DNA preserved in the liquid, this obtained has purified, the high grade skeleton DNA sample.

在处理洗净DNA 需要一次更多磁性小珠洗净处理之后，磁性小珠在具体液体环境之下以DNA 吸附，是固定的在磁场作用一个边之下离心机管，只有有DNA 并且磁性小珠成一体在部份一起被保留，那么用途具体洗脱流动性干净，最后使用双词根水溶化DNA，在现在以前磁性小珠并且DNA 被分离了从， DNA 被保存在液体，这被获得净化了，高级最基本的DNA 样品。

By use of 90 individuals DNA from Gold Queen maize population, 6 inbred lines DNA, and 15 pair SSR primers, the effect of 4 kinds of DNA sample treatments of the individual DNA sample, the mixed DNA sample with 3 individuals, with 10 individuals, and with 15 individuals for the genetic diversity in the same population were compared and analyzed.

以金皇后玉米群体90个单株DNA和6个自交系DNA为供试材料，利用15对SSR引物，比较了同一群体 4种DNA样品处理(单株DNA样品、3个单株混合DNA样品、10个单株混合DNA样品、15个单株混合DNA样品)的SSR遗传多态性。

In this experiment, firstly, the use of 90 individuals DNA from Gold Queen maize population, 6 inbred lines DNA representing Chinese different types of resources, and 15 pairs of SSR primers, the effect of 4 kinds of DNA sample treats of the individual DNA sample, the mixed DNA sample with 3 individuals, with 10 individuals, and with 15 individuals for the genetic diversity in the same population were compared and analyzed.

本研究首先以金皇后玉米群体90个单株DNA和Mo17、B73、丹340、黄早4、掖478、许178等6个具有代表性的自交系为供试材料，利用15对SSR引物，比较了同一群体4种DNA样品处理（单株DNA样品、3个单株混合DNA样品、10个单株混合DNA样品、15个单株混合DNA样品）的SSR遗传多态性。

For maintain the genome integrity and fidelity. DNA repair processes are classified into pathways responsible for repairing specific classes of DNA damage, although recent data indicated that some proteins function in multiple pathways. Base excision repair occurs through excision of a damaged region, followed by fill-in repair synthesis using the opposite strand as a template. Mismatch repair operates on base mismatched and small loop-outs that arising during replication by misincorporation or slippage on the template strand. Nucleotide excision repair removes photoproducts from u.v. radiaton and bulky adducts from a multiple of chemicals. DNA double-strand breaks may be rectified by either homologous recombination repair and nonhomologous end joining pathways where both strands of the DNA duplex are damaged.

DNA修补基因可藉由不同的机制对不同程度的DNA损害进行修复，虽然近来已有文献指出，一些DNA修复蛋白可能参与多种DNA修复机制，不过一般可分为下列四种DNA修复机制：碱基删除修复(Base Excision Repair； BER)，即对较小的DNA损伤，进行修复；核苷酸错误配对删除修复，即对复制时所产生的核苷酸配对错误或模板滑动造成的DNA损害进行修复；核苷酸删除修复(Nucleotide Excision Repair； NER)，即对因紫外线或有机化合物所造成的较大损伤进行修复；以及双股DNA断裂修复(Double-Strand Breaks； DSBs)，即对双股DNA断裂进行修复，此机制又可分为同源染色体的重组与末端接合两种主要路径，对受损的DNA进行修复。

I didn't watch TV last night, because it .

昨晚我没有看电视，因为电视机坏了。

Since this year, in a lot of villages of Beijing, TV of elevator liquid crystal was removed.

今年以来，在北京的很多小区里，电梯液晶电视被撤了下来。