An important functional group,benzo[1,3]dioxole,of alkaloids induces the formation of the human telomeric DNA G-quadruplex

Over the past few decades, numerous molecules have been discovered or designed to interact efficiently and selectively with a peculiar DNA structure named G-quadruplex. Some of these molecules have been developed as anticancer agents. To aid the design of anticancer agents, the ability of alkaloids possessing Protoberberine and Benzophenanthridine groups to induce the formation of G-quadruplexes were studied using CD spectroscopy. By careful examination of their structures, we found that a benzo[1,3]dioxole group plays an important role in influencing their inductive properties. The more functional groups the alkaloids have, the stronger their G-quadruplex inductive ability.     

人体细胞中发现四螺旋DNA结构

据物理学家组织网近日报道，DNA双螺旋结构早已为人熟知，而英国剑桥大学科学家21日在《自然一化学》杂志上发表的论文显示，四螺旋DNA结构，即G-四联体同样存在于人类基因组中。它们形成的区域具有丰富的乌嘌呤基础构件，因此通常缩写为“G”。     

利用DNA数据库串并系列抢劫强奸案

利用DNA数据库对系列抢劫强奸案进行串并。对4起抢劫强奸案所送检材经常规两步消化法提取精子DNA,利用公安部二所研制的DNATyper15试剂盒复合扩增,310DNA测序仪检测,均得到了精子完整的DNA分型并输入DNA数据库。经比对认定这4起案件的精斑DNA中14个STR位点基因型均相同,非父排除率为0.9999997,确定嫌疑人为同一人。DNA数据库建设是侦查破案水平发展的一个重要方向和应用手段,建立和完善全国DNA数据库势在必行。     

稀溶液中线形DNA分子链结构及扩散的布朗动力学模拟

通过构建全参数化的珠一弹簧分子链模型,并运用一种高效稳定的半隐式预测-校验积分算法求解描述稀溶液中DNA分子链结构演化的随机动力学方程组,系统研究了体积排斥作用、有限伸长弹性作用和涨落流体动力学作用对分子链的回旋半径、质心扩散系数以及相应标度指数的影响.模拟结果能够验证良溶剂中分子链Zimm模型的标度规律,并揭示出3种...     

Serine/threonine protein phosphatases in DNA damage response

DNA damage response (DDR) is among the most important of the mechanisms that maintain genome stability which, when destabilized, predisposes organs to cancer. Reversible phosphorylation mediated by protein kinases and protein phosphatases regulates most, if not all, cellular activities, including DDR. Protein kinase inhibitors have become the main focus of targeted therapy and anticancer drug development. However, our limited knowledge of protein phosphatase function is compromising our capacity to develop therapeutic agents against phosphatases. In this review, we summarize the roles of serine/threonine protein phosphatases involved in DDR and propose that in situ dephosphorylation of phosphoproteins by protein phosphatases, instead of proteasome-mediated degradation of phosphoproteins, is mainly employed by cells.     

Mitochondrial DNA variation analysis suggests extreme low genetic diversity in Guizhou snub-nosed monkeys （Rhinopithecus brelichi）

Guizhou snub-nosed monkey (Rhinopithecus brelichi) is a unique, endangered primate in China, mainly distributed in Fanjing Mountain National Natural Reserve, Guizhou Province, in an area of 275 km2. Recently, habitat loss and fragmentation have caused population isolation. To assess genetic diversity within this species and its population structure, we sequenced 400 bp of the hypervariable I segment from the mitochondrial DNA control region for 128 individuals. Only one haplotype was identified from these individuals. Compared with other primate species, R. brelichi can be regarded as a species with very low genetic diversity, which further adds to the conservation concern.     

Habitat-induced reciprocal transformation in the root phenotype of Oriental ginseng is associated with alteration in DNA methylation

Oriental ginseng is an important medicinal plant that grows in 2 major forms or ecotypes, wild and domesticated. Each form differs conspicuously in root phenotype, but can be converted from one type to another by habitat. Here we show that the habitat-induced transformation of ginseng root phenotype was accompanied by alteration in cytosine methylation at a large number of 5′-CCGG-3′ sites detected by the methylation-sensitive polymorphism (MSAP) marker. The collective CG and CHG methylation levels of all 4 landraces of the domesticated form were significantly lower than those of the wild form. Interestingly, artificially transplanted ginseng plants recreated in both directions the methylation levels (at least in CHG) of their natural counterparts. The methylation differences between the 2 ginseng ecotypes were validated at 2 isolated MSAP loci bearing homology to a 5S rRNA gene or a copia retrotransposon. Our results implicate a link between epigenetic variation and habitat-induced phenotypic flexibility in Oriental ginseng.     

不同倍性(2×、3×、4×)鸭梨基因组DNA甲基化水平与模式分析

以鸭梨(Pyrus.bretschneideri Rehd.cv.‘Yali')多倍体(2×、3×、4×)为材料,应用甲基化敏感扩增多态性(methylation sensitive amplified polymorphism,MSAP)技术研究不同倍性鸭梨基因组DNA甲基化水平及模式变化.共筛选22对引物,平均每对引物产生约50条带,统计100～500 bp的扩增带,共计954个位点.分析表明:鸭梨2×、3×、4×分别检测到831、886、852个位点,发生甲基化位点分别占15.5%、20.0%、16.8%,其中全甲基化占9.7%、11.9%、9.7%.分析这些位点甲基化模式表明:甲基化模式在三个倍性间类型相同的占所检测位点的69.2%,仅两种倍性相同的为25.4%,各不相同的占5.5%,其中三倍体41.4%甲基化位点发生改变,显示出独特的DNA甲基化特点.     

LAGE-1DNA肿瘤疫苗的抗肿瘤治疗效果研究

以LAGE-1转染EMT6构建小鼠乳腺癌肿瘤模型;将BalB/c小鼠随机分为4组,以pcDNA3.1/LAGE-1及对照pcDNA3.1分别接种实验组和对照组各三次.于末次免疫后10 d在小鼠左背部、右背部皮下分别种植EMT6肿瘤细胞和EMT6/LAGE1肿瘤细胞．荷瘤后观察成瘤时间、肿瘤大小,并对小鼠脾细胞进行CTL细胞杀伤活性实验来观察DNA疫苗引起的免疫反应.结果显示LAGE-1DNA疫苗在体内能诱导有效的特异性肿瘤免疫应答,该疫苗简便有效.     

无线传感网络中空间失效模式下的数据存储恢复算法

针对空间失效模式下的数据存储和恢复问题,设计了一种基于数据复制的存储和恢复算法.该算法为每个数据节点分配一个冗余节点,在数据节点失效时可以利用冗余节点中的数据来成功恢复数据,并且使整个过程消耗的代价最小.理论分析和仿真实验表明,同Greedy算法相比,在保证成功恢复的同时,该方法显著降低了网络的整体能耗,从而有效延长了网络的生存周期.