想想来自四面八方的快递包裹，如何在物流中心汇集，尔后经分拣、精确投放到各地？我们凭借物流单上的详尽的地址标示保证了整个流程准确无误。在分子视觉下，其实细胞也是一个庞大的物流中心，可是在这里，没有人会“书写地址”，如何保证了“包裹邮件”能正确投放？ 介绍：真核细胞含有多种与膜结合的细胞器，它们分别囊括有不同的内容物，行使了不同的功能。细胞器各自特性的维持依赖于其内容蛋白和脂的高度选择性，维持各自特性的中心则系于叫做囊泡的转运载体。需要弄清其中的机制：不但需要弄清楚特异的“货物”如何出芽进入囊泡而离开供体细胞器的，而且要明白囊泡如何投递给正确的受体细胞器。“货物”到达后，囊泡和其靶向的目的细胞器上的SNARE蛋白能驱动膜融合，因而在细胞器特异性选择中发挥作用。但是，是位于其上游的融合步骤，即囊泡“衔羁”于目的细胞器这一过程，使两边膜上的SNARE蛋白能相互作用、启动融合过程。就是这种为膜运输给予定向特异性的“衔羁”（tether）步骤的重要性，当前尚未弄清。Golgins蛋白是细胞器捕获特异类型囊泡的充分条件。我们假设：如果Golgins“衔羁”囊泡定向运往高尔基体，那我们将golgins蛋白重定位到线粒体上的话，将导致某些特定囊泡被异位捕获（于线粒体上）。免疫荧光证明（了这一假说）：线粒体上表达单一类型golgin蛋白可导致特殊“货物舱”出现异位捕获。电镜结果显示囊泡围绕着这些线粒体聚集分布。 基本原理：为了研究“衔羁”在膜运输特异性中的作用，我们聚焦在高尔基复合体上。高尔基复合体为多“腔室”的细胞器，是分泌和内吞转运通路的交汇口，其承接运往不同目的地的囊泡。高尔基体上有一大个保守的卷曲螺旋蛋白家族—golgins，golgins在高尔基体囊泡衔羁中可能发挥了重要作用。但是，一些golgin突变后呈现的轻微表型，使研究人员难于判定它们在“衔羁”过程中的作用。于是我们使用一种重定位策略来检测在囊泡“衔羁”过程中这类蛋白发挥了充分性作用，而不是必要性作用。选择了十种即便在非脊椎动物依旧保守的哺乳动物golgins，这些golgins分别位于高尔基体不同区域，通过把golgins蛋白的C末端高尔基定位结构域换成线粒体跨膜结构域，让它们在线粒体上异位表达。我们用于不同位置的运载“货物”囊泡的分布作为golgins蛋白在“衔羁”过程中作用的衡量指标(readout)。 结果：我们证明golgins蛋白的亚类(subsets)能将特定的内源性或外源性“货物”重新等位：从运往高尔基体变成运往线粒体。具体的讲，golgin-97, golgin-245和GCC88用于捕获由内体运往高尔基体的囊泡，GM130和GMAP210捕获内质网运往高尔基体的囊泡，golgin-84, TMF和GMAP210捕获高尔基体的常驻蛋白(resident proteins)。另外，电镜超微结构展现了装饰着特定golgins蛋白的囊泡膜围绕线粒体聚集的证据。这些数据表明golgins不但捕获囊泡，而且对来自内体，内质网和高尔基体等不同来源的囊泡具有捕获特异性。 结论：我们证实重新定位特定的golgins蛋白是导致特定类型转运囊泡异位运输的充分条件。因此多数golgins蛋白可决定特定的衔羁过程，它们在囊泡转运到达高尔基体的特异性中起了主要作用。另外，这种定位系统可作为分离这些存在时间短、靶向特异的转运囊泡的有用工具，从而为进一步研究膜转运的特异性提供了新途径。 你必须选择一两种高尔基“衔羁” 细胞内含有大量的各种类型的膜转运囊泡，每种囊泡都需要找到并与其正确的目的细胞器融合。不同囊泡如何与各自不同的靶向细胞器膜相融合喃，这类工作已有很多。在细胞内的膜结构转运通过高尔基复合体中，另外一层特异性就是需特定的膜“衔羁子”（tethers）。然而，这一“衔羁子”的重要性并未阐明。Wong和Munro使用了一种聪明的方法发现“衔羁子”保证了囊泡能正确定向。使用实验手段让“衔羁子”在线粒体表达，能劫持不同的转运囊泡，让它们不再运向正常目的地，而是运到线粒体上。 摘要：高尔基复合体由多个“腔室”组成，是在分泌和内吞的囊泡转运中处于中心地位的分拣站。运载着不同来源“货物”的转运囊泡能选择性接近不同的高尔基“腔室”，其中的机制尚未完全被弄清楚。我们发展了一中重定位和捕获方法，（用它）系统的研究了10种广泛存在的、保守的卷曲螺旋蛋白—golgin的囊泡衔羁活性。我们发现：在高尔基表面上定位不同的golgins亚类，其在捕获不同来源的囊泡上有选择性。这一发现证明：golgins作为体内的“衔羁”因子编码决定了衔羁的特异性，可能在高尔基复合体的膜转运中发挥了主要作用。 链接： http://www.sciencemag.org/content/346/6209/1256898.abstract 文题：The specificity of vesicle traffic to the Golgi is encoded in the golgin coiled-coil proteins Introduction The eukaryotic cell contains membrane-bound organelles with distinct functionality and composition. Preservation of organelle identity depends on the highly selective transfer of proteins and lipids between compartments. Central to this are transport carriers called vesicles. Mechanisms are required not only for the selective incorporation of specific cargos into vesicles as they bud off a donor organelle, but also for the correct delivery to an acceptor organelle. SNARE proteins on the vesicle and destination organelle drive membrane fusion after arrival and have been implicated in contributing to specificity in choice of organelle. However, upstream of the fusion step, a process called tethering is thought to initially attach the vesicle to the destination organelle and then bring it close to allow the SNARE proteins on opposite membranes to interact. The importance of tethering in conferring specificity to membrane traffic is currently unclear. Golgins are sufficient to capture specific classes of vesicle. We hypothesized that if the golgins tether vesicles destined for the Golgi, then their relocation to mitochondria should result in ectopic capture of specific classes of vesicle. Immunofluorescence demonstrates that the presence of a single golgin on mitochondria results in the ectopic capture of a specific cargo. Electron microscopy reveals that vesicle s accumulate around these mitochondria. Rationale To study the contribution of tethering to specificity in membrane trafficking, we focused on the Golgi apparatus. The Golgi complex is a multicompartment organelle at the intersection of secretory and endocytic trafficking pathways and so receives vesicles from a range of destinations. A family of well-conserved large coiled-coil proteins on the Golgi, the golgins, have been suggested to function as vesicle tethers at the Golgi. However, mild phenotypes of golgin mutants have presented a challenge for elucidating their in vivo roles. We thus used a relocation strategy to test for their sufficiency rather than necessity in vesicle tethering. Ten mammalian golgins that are conserved outside of vertebrates and found on different regions of the Golgi were ectopically expressed at the mitochondria through attachment to a mitochondrial transmembrane domain in place of their C-terminal Golgi targeting domain. We then used the distribution of cargo-laden vesicles originating from different locations as a readout for the golgins’ tethering activity. Results We demonstrate that subsets of golgins are capable of redirecting particular endogenous or exogenous cargo destined for the Golgi to an ectopic site, the mitochondria. Specifically, golgin-97, golgin-245, and GCC88 were able to capture endosome-to- Golgi cargos; GM130 and GMAP210 were able to capture endoplasmic reticulum (ER)–to-Golgi cargos; and golgin-84, TMF, and GMAP210 were able to capture Golgi resident proteins. Furthermore, electron microscopy yielded ultrastructural evidence for the accumulation of vesicular membranes around mitochondria decorated with specific golgins. These data suggest that not only do the golgins capture vesicles, but they also exhibit specificity toward vesicles of different origins-from the endosomes, from the ER, or from within the Golgi itself. Conclusion We have been able to demonstrate that relocation of specific golgins is sufficient to reroute specific classes of transport vesicles to an ectopic site. Thus, most golgins are sufficient to nucleate a specific tethering process, and hence they are likely to make a major contribution to the specificity of vesicle traffic arriving at the Golgi. In addition, this relocation system may be a useful tool for isolating specific transport vesicles that are normally short-lived, hence providing a route to further understanding of specificity in membrane traffic. You've got to pick a Golgi tether or two The inside of the cell contains a large variety of different membrane transport vesicles, each of which needs to find and fuse with its correct target destination. The detailed mechanism specifying which vesicle can fuse with which target membrane has been the subject of an enormous amount of research. An additional layer of specificity in intracellular membrane trafficking across the Golgi complex is thought to involve particular membrane “tethers.” However, the importance of these tethers has been unclear. Wong and Munro used a clever trick to reveal how specific tethers can indeed ensure correct vesicle destination. Tether proteins experimentally expressed on mitochondria hijacked different transport vesicles and diverted them from their normal destination to the mitochondria. Abstract The Golgi apparatus is a multicompartment central sorting station at the intersection of secretory and endocytic vesicular traffic. The mechanisms that permit cargo-loaded transport vesicles from different origins to selectively access different Golgi compartments are incompletely understood. We developed a rerouting and capture assay to investigate systematically the vesicle-tethering activities of 10 widely conserved golgin coiled-coil proteins. We find that subsets of golgins with distinct localizations on the Golgi surface have capture activities toward vesicles of different origins. These findings demonstrate that golgins act as tethers in vivo, and hence the specificity we find to be encoded in this tethering is likely to make a major contribution to the organization of membrane traffic at the Golgi apparatus. 上文由群晓科苑翻译整理，科学推广，服务民众。他人或机构如需使用，请提供该原始链接地址。 北京群晓科苑生物技术有限公司主要经营生物医药领域的试剂、耗材和仪器。群晓生物致力于为用户提供优质的材料、技术和实验整体性解决方案，完美配合用户的科研创意和灵感。群晓生物立志把一流的产品、专业的技术和完善的售后服务献给广大用户。 北京群晓科苑生物技术有限公司 www.qbioscience.com www.qbiotec.com Tel: 010-84504282/64880108 qbioscience@126.com
现在的国际学术会议基本都有中国学者的身影，英语也越来越好。但发现提问环节有个现象，很有趣，比较中国特色。是什么呢？就是喜欢评论提问问题的好坏It is a good question。 一般做完报告都有几分钟的提问的时间，我们中国学者有个特点喜欢评论It is a good question, 然后第二个人提问题的时候，又说是a good question，第三个人问的时候，还要说a good question，但是自己好像也觉得太俗套了，说的就不那么坚决了，显得很尴尬。 还有的学者是针对人，如果是某个大牛，说是a good question；如果是毛头小子，基本不那么友好，这是根据提问者身份选择性给good question。这点就更不应该了，处处都不忘等级。应该和国外学者一样，平等认真对待每个人的提问。 这在国外很不普遍，有的会偶尔用一下，有的干脆不用；也有的学者就机智多了，他们会有不同说法，譬如，会说我文章评审的时候评委提的问题和你的很像，你不是那个评委吧？！缓和气氛，大家都笑了。 中国学者融入国际舞台，请修改下提问环节；中国学者独步国内舞台，少点矫情！
碳纳米管（CNTs）作为一种具有独特结构与性质的新材料，在许多领域中都有重要的应用前景。在手性药物的研发中，人们都十分希冀能得到单一手性（纯手性）的活性药物分子。然而，要将纯手性的药物成功开发并推向市场，却是一项十分艰难的工作。从根本上讲，是因为手性合成、手性分离的困难，以及由此带来的高成本。 最近的一项研究，向人们展示了手性选择性试剂修饰的碳纳米管（chiral selector modified CNTs，CSM-CNTs），在药物对映体分离中的成功应用。 这项研究工作是由中南大学的Jingang Yu及其合作者完成的，研究结果于今年5月25日在线发表在《 中国化学 》（ Chinese J. Chem. ）杂志上。他们提出了一种用羟丙基-β-环糊精（HP-β-CD）实现多壁碳纳米管（MWCNTs）功能化的新方法，并将这种功能化修饰的MWCNTs作为薄层色谱固定相的添加剂，去分离一种兽药，“瘦肉精”——克仑特罗（clenbuterol）的对映体混合物，得到了令人满意的结果，手性分离因子 。 （Taken from http://www.chemistryviews.org/ ） (clenbuterol) Reference : J. Yu, D. Huang, K. Huang, Y. Hong, Preparation of Hydroxypropyl-β-cyclodextrin Cross-linked Multi-walled Carbon Nanotubes and Their Application in Enantioseparation of Clenbuterol ， Chinese J. Chem. 2011 , 29(5) , 893—897. DOI: 10.1002/cjoc.201190185
【Wolf's Fable】 life is information，living is game. 本人整理了一些自己的思考分享给大家，所有这些论调都非细胞生物学的标准答案，目的是通过思辨逐步逼近事物的本质，愿意吸纳各种思想来丰富《细胞生物学魔鬼字典》，更欢迎不同声音的批判！ 生命是在环境选择性压力下的自适应程序组（life is adaptive programs in the selective pressure of environment） 基因就是功能程序模块（gene is program module） 生物就是可以执行自我复制功能的程序载体（creature are beings with the ability of procedural proliferation） 大自然是生命的编程师（nature is programmer of life，God 1.0） 单细胞生物——程序组间松散的合作群落（unicellular organisms—— Loose collaboration of programs ） 原始多细胞生物——程序组的原始分工协作组织（Multicellular organisms—— specific collaboration programs ） 哺乳动物——程序组的紧密的分工合作体系（mammals are tight cooperation system of programs） 生命活动就是程序的执行和重编程（living is execution and reprogramming of program） 进化就是大自然对生物种群的重编程（evolution——reprogramming of life ） 发育就是程序组依照时空顺序的执行过程（development is space time sequencing of program ） 分化就是细胞功能程序模块选择性地开启和关闭（differentiation is selective openning and closing of Programs） 疾病就是细胞重编程的产物（disease is reprogramming of cells ） 炎症就是微环境对体细胞的重编程现象（Inflammation is the reprogramming process of somatic cell in vivo！） 药物就是细胞微环境调节性物质（so-called medicine is niche regulator） 细胞就是一套能够执行完整自适应功能的基本程序组合（cell is a set of basic portfolio of complete life program.） 遗传物质是细胞源程序文库（hereditary substance is library of program） 细胞质是生命程序的编译场所（cytoplasm is the workshop for program compilation） 细胞膜是程序载体的边界（membrane is boundary of life） 微环境就是细胞程序员（microenviroment is programmer of cells） 微环境决定细胞的命运（microenviroment determine cell fate） 细胞质掌握细胞命运（cytoplasm master cell fate！） RNAs是细胞命运的操纵者(RNAs are cytoplasmic determinants) 微小RNA就是细胞命运操纵子(miRNA——The manipulator ofcell fate！) 细胞的可增殖性就是分化潜能（Proliferation is differentiation potentiality） 细胞的不对称分裂就是分化（differentiation——asymmetric cell division ！ 死细胞就是不可逆地丧失增殖能力的细胞（dead cell is cell with irreversiblly losing of proliferative ability） 活细胞就是干细胞（viable cell is proliferative cell is stem cell ，《Cell Stem Cell》means “cell is stem cell”） 癌本质上是远古单细胞生物在哺乳动物体中的返祖重现（ cancer is atavistic reappearance of unicellular organisms） 癌现象是细胞生命的原始本能（Cancer phenomenon is the primitive instinct of cells ） 癌源自可再生细胞源自体细胞的重编程（cancer origins from the regenerative cells results from reprogramming of somatic cells） 癌症起始细胞就是内源性重编程多能干细胞（endogenous iPS is the cancer initiating cell） 癌是在恶劣微环境中正常体细胞（cancer——good cells in bad niche！） 癌是在异常的细胞质中正常基因组（cancer —— good nuclear in bad cytoplasm） 子曰：上善若水 大成若缺干细胞治疗的终极解决方案就是不使用外源干细胞（cell-free is the final solution of stem cell therapy ）
Journal of Power Sources Article in Press, Accepted Manuscript - Note to users doi:10.1016/j.jpowsour.2011.02.048 | How to Cite or Link Using DOI Copyright 2011 Published by Elsevier B.V. Permissions Reprints Nafion/Polyvinylidene fluoride blend membranes with improved ion selectivity for vanadium redox flow battery application Zhensheng Mai a , b , Huamin Zhang a , , , Xianfeng Li a , , Shaohua Xiao a , b and Hongzhang Zhang a , b a PEMFC Key Materials and Technology Laboratory, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China b Graduate University of the Chinese Academy of Sciences, Beijing 100039, China Received 11 November 2010; revised 25 January 2011; accepted 17 February 2011. Available online 24 February 2011. Abstract Nafion/PVDF blends are employed to prepare the ion exchange membranes for vanadium redox flow battery (VRB) application for the first time. The addition of the highly crystalline and hydrophobic PVDF effectively confines the swelling behavior of Nafion. In VRB single cell test, the Nafion/PVDF binary membranes exhibit higher columbic efficiency than recast Nafion at various current densities. The blend membrane with 20wt% of PVDF (N0.8P0.2) shows energy efficiency of 85% at 80mAcm−2, which is superior to that of recast Nafion. N0.8P0.2 membrane also possesses twice longer duration in OCV decay test and much lower permeation of VO2+ compared with recast Nafion. These results indicate that the addition of PVDF is a simple and efficient way to improve the ion selectivity of Nafion, and the polymer blends with optimized mass fraction of PVDF show good potential for VRB application. Keywords: polymer blends; ion exchange membranes; vanadium redox flow battery
我感觉这是种好方法.具体原理不介绍了,要推荐文章,首推徐云碧老师的这篇 Sun et al 2010 Efficiency of selective genotyping for genetic analysis of complex traits and potential applications in crop improvement( http://image.sciencenet.cn/olddata/kexue.com.cn/upload/blog/file/2010/12/201012914539120891.pdf ) 根据我的习惯,我喜欢把同一类东西放一起,先把文献放这,全文有空再传. 1 Ayoub, M., and Mather, D.E. (2002). Effectiveness of selective genotyping for detection of quantitative trait loci: an analysis of grain and malt quality traits in three barley populations. Genome 45, 1116-1124. Chen, Z., Zheng, G., Ghosh, K., and Li, Z. (2005). Linkage disequilibrium mapping of quantitative-trait Loci by selective genotyping. Am J Hum Genet 77, 661-669. 2 Foolad, M.R., Zhang, L.P., and Lin, G.Y. (2001). Identification and validation of QTLs for salt tolerance during vegetative growth in tomato by selective genotyping. Genome 44, 444-454. Huang, B.E., and Lin, D.Y. (2007). Efficient association mapping of quantitative trait loci with selective genotyping. Am J Hum Genet 80, 567-576. 3 Linde, M., Hattendorf, A., Kaufmann, H., and Debener, T. (2006). Powdery mildew resistance in roses: QTL mapping in different environments using selective genotyping. Theor Appl Genet 113, 1081-1092. Manichaikul, A., Palmer, A.A., Sen, S., and Broman, K.W. (2007). Significance thresholds for quantitative trait locus mapping under selective genotyping. Genetics 177, 1963-1966. 4 Manichaikul, A., and Broman, K.W. (2009). Binary trait mapping in experimental crosses with selective genotyping. Genetics 182, 863-874. 5 Navabi, A., Mather, D.E., Bernier, J., Spaner, D.M., and Atlin, G.N. (2009). QTL detection with bidirectional and unidirectional selective genotyping: marker-based and trait-based analyses. Theor Appl Genet 118, 347-358. 6 Sen, S., Johannes, F., and Broman, K.W. (2009). Selective genotyping and phenotyping strategies in a complex trait context. Genetics 181, 1613-1626. 7 Xing, C., and Xing, G. (2009). Power of selective genotyping in genome-wide association studies of quantitative traits. BMC Proc 3 Suppl 7, S23.
标签: 选择性
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