| Metal-tagging Transmission Electron Microscopy for Localisation of Tombusvirus Replication Compartments in Yeast
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Author:
Date:
2018-04-20
[Abstract] Positive-stranded (+) RNA viruses are intracellular pathogens in humans, animals and plants. To build viral replicase complexes (VRCs) viruses manipulate lipid flows and reorganize subcellular membranes. Redesigned membranes concentrate viral and host factors and create an environment that facilitates the formation of VRCs within replication organelles. Therefore, efficient virus replication depends on the assembly of specialized membranes where viral macromolecular complexes are turned on and hold a variety of functions. Detailed characterization of viral replication platforms in cells requires sophisticated imaging approaches. Here we present a protocol to visualize the three-dimensional organization of the tombusvirus replicase complex in yeast with MEtal-Tagging Transmission Electron ...
[摘要] 正链（+）RNA病毒是人，动物和植物中的细胞内病原体。构建病毒复制酶复合物（VRC）病毒操纵脂质流动和重组亚细胞膜。重新设计的膜集中了病毒和宿主因子，并创造了促进复制细胞器内VRC形成的环境。因此，有效的病毒复制取决于病毒大分子复合物开启并具有各种功能的特殊膜的组装。细胞中病毒复制平台的详细特征需要复杂的成像方法。在这里我们提出一个协议，用肉眼标记透射电子显微镜（METTEM）可视化酵母中的tombusvirus复制酶复合物的三维组织。该协议使我们能够用METTEM和电子断层扫描成像三维病毒复制酶分子的细胞内分布。我们的研究显示病毒复制酶分子如何在特化细胞膜内构建复制复合物。
【背景】正链RNA病毒的复制取决于细胞膜的重塑。细胞内膜作为VRC装配的结构支架，提供调节病毒复制酶活性和保护病毒RNA免受宿主抗病毒防御的必需脂质和辅因子（Miller和Krijnse-Locker，2008; den Boon <等，2010; nagy和pogany，2011;="" nagy，2016）。电子显微镜观察到具有活性vrc的复制细胞器的结构。="" vrc以单个膜囊或'小球'，管状球形立方体膜，双膜囊泡（dmv）或平面寡聚体阵列装配（de="" castro等人，2013）。通常在rna病毒感染的细胞中观察到小球。它们通过在各种细胞器中内陷而形成，并具有对胞质溶胶的狭窄开口（den="" boon="" et=""> ...
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| Method for Multiplexing CRISPR/Cas9 in Saccharomyces cerevisiae Using Artificial Target DNA Sequences
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Author:
Date:
2017-09-20
[Abstract] Genome manipulation has become more accessible given the advent of the CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) editing technology. The Cas9 endonuclease binds a single stranded (single guide) RNA (sgRNA) fragment that recruits the complex to a corresponding genomic target sequence where it induces a double stranded break. Eukaryotic repair systems allow for the introduction of exogenous DNA, repair of existing mutations, or deletion of endogenous gene products. Targeting of Cas9 to multiple genomic positions (termed ‘multiplexing’) is achieved by the expression of multiple sgRNAs within the same nucleus. However, an ongoing concern of the CRISPR field has been the accidental targeting of Cas9 to alternative (‘off-target’) DNA locations within a genome. We ...
[摘要] 鉴于CRISPR（集群定期间隔短回归重复）编辑技术的出现，基因组操纵变得更加易于使用。 Cas9核酸内切酶将募集复合物的单链（单向导）RNA（sgRNA）片段结合到相应的基因组靶序列，引发双链断裂。真核修复系统允许引入外源DNA，修复现有突变或内源基因产物的缺失。通过在同一核内表达多个sgRNA来实现Cas9对多个基因组位置的定位（称为“多重”）。然而，CRISPR领域的持续关注是将Cas9意外地定位到基因组内的替代（“脱靶”）DNA位置。我们将安装的人造Cas9靶序列的使用（称为人造基因座上的Cas9复制）描述为允许（i）与单个sgRNA复用的酵母基因组中的用途; （ii）减少/消除可能的脱靶效应，以及（iii）精确控制预定目标序列的放置。
【背景】CRISPR（集群定期间隔回归重复）机制已经在原核生物中演变为具有很高精度编辑任何基因组的能力的原始适应性免疫系统（Jinek等，2012; Sorek等，2013）。这种生物技术需要使用来自化脓性链球菌（或othologous物种）的内切核酸酶（Cas9），单个RNA'引导'序列和外源供体DNA（如果需要）。仅在短短几年内，CRISPR / ...
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| Rapid Determination of Cellulose, Neutral Sugars, and Uronic Acids from Plant Cell Walls by One-step Two-step Hydrolysis and HPAEC-PAD
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Author:
Date:
2016-10-20
[Abstract] The plant cell wall is primarily composed of the polysaccharides cellulose, hemicellulose and pectin. The structural and compositional complexity of these components are important for determining cell wall function during plant growth. Moreover, cell wall structure defines a number of functional properties of plant-derived biomass, such as rheological properties of foods and feedstock suitability for the production of cellulosic biofuels. A typical characterization of cell wall chemistry in the molecular biology lab consists of a mild acid hydrolysis for the quantification of hemicellulose and pectin-derived monomers and a separate analysis of cellulose by the Updegraff method. We have adopted a streamlined ‘one-step two-step’ hydrolysis protocol that allows for the simultaneous ...
[摘要] 植物细胞壁主要由多糖纤维素，半纤维素和果胶组成。这些组分的结构和组成复杂性对于确定植物生长期间的细胞壁功能是重要的。此外，细胞壁结构限定了植物来源的生物质的多种功能性质，例如食品的流变性质和用于生产纤维素生物燃料的原料适用性。分子生物学实验室中细胞壁化学的典型表征包括用于定量半纤维素和果胶衍生单体的温和酸水解和通过Updegraff方法对纤维素的单独分析。我们采用了一个简化的"一步两步"水解方案，允许通过配对的脉冲安培检测（HPAEC-PAD）的高效阴离子交换层析同时测定纤维素含量，中性糖和糖醛酸样品。在我们的工作中，该方案已经在很大程度上替代了Updegraff纤维素定量和用2μMTFA水解以在微量级上测定基质多糖组成。
[背景] 是基于在121℃下在4％（w/v）硫酸中水解的样品的配对分析。一组样品首先用72％（w/w）硫酸预处理以使纤维素膨胀并使其易于稀释酸水解（图1中的Saeman水解; ...
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