Rad51 and DNA-PKcs are involved in the generation of specific telomere aberrations induced by the quadruplex ligand 360A that impair mitotic cell progression and lead to cell death

Functional telomeres are protected from non-homologous end-joining (NHEJ) and homologous recombination (HR) DNA repair pathways. Replication is a critical period for telomeres because of the requirement for reconstitution of functional protected telomere conformations, a process that involves DNA repair proteins. Using knockdown of DNA-PKcs and Rad51 expression in three different cell lines, we demonstrate the respective involvement of NHEJ and HR in the formation of telomere aberrations induced by the G-quadruplex ligand 360A during or after replication. HR contributed to specific chromatid-type aberrations (telomere losses and doublets) affecting the lagging strand telomeres, whereas DNA-PKcs-dependent NHEJ was responsible for sister telomere fusions as a direct consequence of G-quadruplex formation and/or stabilization induced by 360A on parental telomere G strands. NHEJ and HR activation at telomeres altered mitotic progression in treated cells. In particular, NHEJ-mediated sister telomere fusions were associated with altered metaphase-anaphase transition and anaphase bridges and resulted in cell death during mitosis or early G1. Collectively, these data elucidate specific molecular and cellular mechanisms triggered by telomere targeting by the G-quadruplex ligand 360A, leading to cancer cell death.     

Water in granulites: implications for the nature and evolution of the lower continental crust

The lower continental crust is one of the most important sphere-layers in the deep earth, and is the direct place where the crust-mantle interactions occur. Granulites are the dominated rocks in the lower crust, and have critical implications for the knowledge of the composition, nature and evolution of the deep crust; fluids are important mediums influencing many geochemical, geophysical and geodynamical characteristics of the lower crust, and may also play a fundamental role in the petrogenesis of granulites and the formation of the lower crusts. In this paper, we review recent advances involved with the deep continental crust, granulites and fluids, and some long-standing debates. Combined with the Fourier-transform infrared spectroscopy (FTIR) analysis performed on the mineral assemblages (cpx, opx, plag and grt) in lower crustal granulite xenoliths and terrains (exposed section) from east China, it is suggested that structural water, dominated by OH, in these nominally anhydrous phases may constitute the most important water reservoir in the deep crust. This structual water may help to understand many lower crustal geological processes and phenomena (e.g. seismic activities and electrical conductive anomalies), and influences from these water must be taken into consideration.     

环草石斛化学成分研究

环草石斛是中医临床上广泛应用的石斛药材。为了进一步研究环草石斛的药效成分,采用硅胶、LH-20凝胶及C-18反相硅胶等柱色谱技术对其甲醇提取液进行了系统分离,结果得到7个化合物,分别是:石斛宁(1),2,4,7-三羟基-9,10-二氢菲(2),2,5-二羟基-4-甲氧基菲(3),loddigesiinols C(4),杓唇石斛酚(5),石斛酚(6),3,4’,5-三羟基-3’-甲氧基联苄(7)。这些化合物的结构由质谱、核磁共振波谱数据确定,其中化合物2、7首次在环草石斛中分离得到。     

大都市的现代农业（下）——巴黎大区的生态农业

随着城镇的扩张，城市与乡村旧有的关系不再存在，一种新的关系正在演化形成。它主导着乡村和农业新的目标和行为。城市化的最大特征是市中心主导和集中就业．与此同时，也带来了更高的流动性这种流动性使得巴黎大区的很多人住得更靠近巴黎城区．与巴黎城连为一体，从而过上了城市化的生活。反过来，流动性也使得原本住在城区的居民外走到乡间，进行旅游和休闲。     

中小直销企业的出路

案例回放: 2007年,一家名为立康立全球国际有限公司的企业在香港成立。成立初期,也许是2007年月朗国际的飞速发展给了立康立公司以启示,在系统组建上,立康立采用了与月朗同样的方式——单一系统。立康立惟一的系统是E系统,它是由立康立公司副总裁赖政希创立,赖政希在系统建设方面有着丰富的经验。在立康立时创立的K系统在大陆市场曾获得不错的业绩,同时也吸引到诸如易文革、陈武川、董德、郑柯和杨滨等直销名人的加入,一时间在行业炒得沸沸扬扬,引起众多行业同仁的关注。     

广东麒麟幔源角闪石巨晶的氢同位素组成及其指示意义

运用离子微探针分析技术测定了广东麒麟的５个幔源角闪石巨晶的氢同位素组成。无论是５个样品之间，还是每个样品内部，δＤ值和氢含量都十分均一，说明其形成环境很稳定，麒麟角闪石的源区具有高于地幔原始值的δＤ值，说明源区存在再循环的地壳组分。再循环地壳组分的来源可能与中生代时期太平洋板块向欧亚板块的俯冲有关，座冲过程也可能是引起样品具有Ｄｕｐａｌ异常的原因。     

7475铝合金板材的各向异性疲劳性能

基于高周疲劳弯曲实验,研究了航空用铝合金板材Al7475-T3的各向异性疲劳行为.结果表明：轧制后形成了扁平长条状结构的7475-T3铝合金具有良好的耐疲劳损伤性能.在室温弯曲加载条件下,从3个平面（S-T,S-L,T-L）截取的光滑试样的疲劳极限最高可达200 MPa,除在T-L面上表现为各向同性外,其余两面的疲劳性能均表现出各向异性.采用以最弱链接理论为基础的概率疲劳准则,分析了铝合金板材中疲劳裂纹产生的可能性,但模拟结果与实际相差较远.综合考虑晶粒有效滑移长度和夹杂物尺寸两因素,对疲劳极限的影响进行模型计算,得出的Kitagawa曲线与实际情况比较吻合.     

灾后重建，为长远复兴预留空间——太子港重建：立足生态城市理念

近年来,频繁的地震给人类带来的威胁,依然决定着21世纪人类的居住。2008年的中国汶川大地震和2010年的海地太子港大地震,都给数以万计的人们带来了深重的灾难。2011年8月。在加拿大蒙特利尔市——太子港的姐妹城市,举行了第九届生态城市世界峰会．峰会的主要议题是海地首都太子港震后一年半时间来的重建进展!     

守内安护航邮件安全

近年来,邮件将死的预测纷纷流传于耳,但现状并非如此.数据表明,电子邮件的用量和数量仍在不断地增长,无论微信、微博等新媒体信息流如何风靡一时,企业级的信息流转工具始终还是依赖电子邮件的传递与沟通.电子邮件没有被取代,尤其企业对电子邮件上通下达的功用极为依赖.守内安信息科技上海(有限)公司(以下简称“Softnext守内安”)自从在全世界率先推出一套处理双字节内容的企业级中文反垃圾邮件产品之后,多年来不断提升邮件安全领域的专业与专注度,守护用户邮箱安全.     

邮件安全守护有良策

电子邮件在企业内部和外部沟通过程中扮演着十分重要的角色,但是许多人对于邮件安全持有错误的观念,例如:认为自己的邮箱有密码,信息泄露不会发生在邮件的通信过程中.根据Oysterman Research调查显示,"83％的企业认为机密信息泄露只是偶然事件,很大一部分原因是由于内部员工不了解相关安全规定,或没有意识到他们传递的信息带有机密性而已."因此,不难看出目前很多企业还没有关注到邮件安全的重要性,特别是缺乏对于一旦发生信息泄露事件,对企业造成潜在损失的清醒认识.