Symmetrical directional cloning: An efficient method to prepare hairpin RNA interference constructs

RNA interference (RNAi) is a loss-of-function approach by which double-stranded RNA (dsRNA) initiates degradation of homologous mRNAs in a sequence specific manner. The dsRNA molecules can be produced in vitro or in vivo, and can be introduced to cells in a number of ways. Here we report a more efficient method for the cloning of inverted repeat DNA fragments into expression vectors that can be transcribed into effective dsRNA molecules in vivo or in vitro. This method, named Symmetrical Directional Cloning (SDC), takes the advantage of compatible non-palindromic restriction enezyme sites, which allow one to directionally clone a single PCR product in both the sense and antisense orientations together into a vector. SDC allows for the directional cloning of inverted repeats using a single PCR product; it requires only one cut site on each side of the loop. Hence this method is more cost effective and less time-consuming. At least 21 commercially available restriction endonucleases can be used as cloning sites for the SDC method. The efficacy of dsRNA expression vectors prepared by SDC has been demonstrated by targeting a negative regulator of the signaling pathway mediating the response of cells to phytohormone, gibberellins (GA), in the aleurone cells.     

务实人终成大事业--小记华东理工大学于广锁教授

于广锁是华东理工大学洁净煤技术研究所副所长，年方35岁。两周前的一天，我到该校洁净煤技术研究所采访，那天的主角是洁净煤所的创建人、老所长于遵宏教授，小于只是在旁参与介绍情况，但这位后生憨厚的面容，他对老先生的敬重，引起了我的注意。当了解到小于是2003年入选的启明星时，我即提出采访要求。小于推却说，     

Optimization of wear parameters of binary Al-25Zn and Al-3Cu alloys using design of experiments

Zinc-aluminum alloys have been used as bearing materials in the past. In recent years, binary Al-Zn alloys and Al-Zn-Cu alloys are being used as an alternative to the Zn-Al alloys for bearing applications. In this study, both binary Al-25Zn and Al-3Cu were prepared using stir casting process. Homogenization of the as-cast alloys was performed at 350℃ for 8 h and then, the alloys were furnace-cooled to 50℃. The homogenization led to the removal of the dendritic structure of the as-cast alloys. After homogenization, wear parameters optimization was carried out using Taguchi technique. For this purpose, L₉ orthogonal array was selected, and the control parameters selected are load, velocity, and sliding distance. The optimum parametric condition was obtained using signal-to-noise (S/N) ratio analysis, and specific wear rate (SWR) is the selected response. The "smaller-the-better" is the goal of the experiment for S/N ratio analysis. After the optimization, confirmation tests were carried out using analysis of variance (ANOVA) from the developed regression equation. Finally, wear mechanism studies were conducted using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) images.     

一个方向,三代人的坚守——访海军军医大学药学院副院长盛春泉教授

<正>专攻真菌的启明星选择2009级星友、海军军医大学(原第二军医大学)药学院的盛春泉教授作为本期启明星专访对象要追溯到2018年6月的岳阳论坛,那是上海中医药大学启明星联谊会组织的青年学者论坛,以会议举办地岳阳医院命名。盛春泉是那次论坛的特邀报告嘉宾,他所做的题为"抗真菌药物设计和     

全球健康成为本次大会最热门话题

<正>37位诺贝尔奖获得者与600位年轻科学家聚会第64届林道大会——在6月底、7月初于德国南部城市林道召开的第64届林道大会上,37位诺贝尔奖获得者与600余名年轻科学家一起分享他们在包括癌症、艾滋病、人体免疫系统等方面研究的新认识,其中包括30名参会的中国博士生。本届林道大会也是历史上首次女性参加者比例高于男性,女性占52%,男性占48%。为使读者了解一批顶尖科学家在健康问题上的思考和见解,本刊辑选了这组报道。     

淋巴瘤免疫疗法的探索者——访上海交通大学附属瑞金医院闫子勋医生

<正>她叫闫子勋,是本期启明星的专访对象,上海交通大学附属瑞金医院的一名医生。她17年前与医结缘,一颗坚守梦想的种子,在上海瑞金医院的血液科土壤里生根发芽,并开始了淋巴瘤免疫疗法的探索之路。在中国,说到血液病,特别是血液肿瘤恐怕无人不知上海瑞金医院血液科,这里有王振义、陈竺、陈赛娟、陈国强、赵维莅等几代杰出的临床医生科学家团队在护卫病患的健康,这     

使每秒千万条数据存储成为可能的年轻人——访上海宝信软件股份有限公司专业技术总监沈春锋博士

<正>我近年来采访的启明星里,70年代末及80年代这一时段的人比例越来越高。我明显感到,这个年龄段的人更少有传统的羁绊,他们更愿意从自己的视角去看周围的世界,去把握自己的人生道路。而且,由于教养相对较好的原因,这一批人普遍知书识礼,尽管面对的生存发展环境和机遇更为严苛,但他们普遍比较开放、乐观。这种感觉已有一段时间,而在我上周访问了去年入选启明星、来自宝信软件的系统架构师沈春锋(上图)后     

癌症终可治——人类抗癌之战40年的启示

近一段时间．国际科学共同体关注的一个话题是纪念“人类抗癌之战40年”，全球最知名的两本科学刊物——英国的《自然》和美国的《科学》在3月底4月初先后刊登与癌症有关的专题报道，《自然》的专题重在讲癌症的预防，《科学》则比较全面，除了刊发社论，     

Novel neurotrophic factor CDNF protects and rescues midbrain dopamine neurons in vivo

In Parkinson's disease, brain dopamine neurons degenerate most prominently in the substantia nigra. Neurotrophic factors promote survival, differentiation and maintenance of neurons in developing and adult vertebrate nervous system. The most potent neurotrophic factor for dopamine neurons described so far is the glial-cell-line-derived neurotrophic factor (GDNF). Here we have identified a conserved dopamine neurotrophic factor (CDNF) as a trophic factor for dopamine neurons. CDNF, together with its previously described vertebrate and invertebrate homologue the mesencephalic-astrocyte-derived neurotrophic factor, is a secreted protein with eight conserved cysteine residues, predicting a unique protein fold and defining a new, evolutionarily conserved protein family. CDNF (Armetl1) is expressed in several tissues of mouse and human, including the mouse embryonic and postnatal brain. In vivo, CDNF prevented the 6-hydroxydopamine (6-OHDA)-induced degeneration of dopaminergic neurons in a rat experimental model of Parkinson's disease. A single injection of CDNF before 6-OHDA delivery into the striatum significantly reduced amphetamine-induced ipsilateral turning behaviour and almost completely rescued dopaminergic tyrosine-hydroxylase-positive cells in the substantia nigra. When administered four weeks after 6-OHDA, intrastriatal injection of CDNF was able to restore the dopaminergic function and prevent the degeneration of dopaminergic neurons in substantia nigra. Thus, CDNF was at least as efficient as GDNF in both experimental settings. Our results suggest that CDNF might be beneficial for the treatment of Parkinson's disease.