{{'Search' | translate}}
 

PBS

PBS,pH 7.4

Company: Thermo Fisher Scientific
Catalog#: 10010023
Bio-protocol()
Company-protocol()
Other protocol()

Characterization of Protein Domain Function via in vitro DNA Shuffling
Author:
Date:
2018-06-05
[Abstract]  We recently investigated the molecular events that drive evolution of the CTX-M-type β-lactamases by DNA shuffling of fragments of the blaCTX-M-14 and blaCTX-M-15 genes. Analysis of a total of 51 hybrid enzymes showed that enzymatic activity could be maintained in most cases, yet the enzymatically active hybrids were found to possess much fewer amino acid substitutions than the few hybrids that became inactive, suggesting that point mutations in the constructs rather than reshuffling of the fragments of the two target genes would more likely cause disruption of CTX-M activity. Certain important residues that played important functional roles in mediating enzyme activity were identified. These findings suggest that DNA shuffling is an effective ... [摘要]  我们最近研究了通过对CTX-M-14和EMX-M-14的片段进行DNA改组来驱动CTX-M型β-内酰胺酶进化的分子事件, bla CTX-M-15基因。 总共51种杂合酶的分析显示酶活性在大多数情况下可以保持,但是酶活性杂合体被发现比少数杂交体具有少得多的氨基酸取代,这表明构建体中的点突变而不是 两个靶基因片段的重新洗牌将更可能导致CTX-M活性的破坏。 确定了一些在介导酶活性中起重要作用的重要残基。 这些发现表明,DNA改组是一种有效的方法来鉴定和表征细菌蛋白质中的重要功能结构域。

【背景】DNA重组是一种自然过程,通过该过程,细菌之间交换遗传物质以增强环境压力下的生存适应性。几种杂交CTX-M-内酰胺酶(CTX-M-64,CTX-M-123,CTX-M-137和CTX-M-132)可能是由bla CTX-M-14和 bla CTX-M-15基因是世界上最常见的变异体,近年来已有报道(Nagano et al。 ,2009; Tian et al。,2014; He et al。,2015; Liu et。, 2015年)。在这些杂合酶中,包含CTX-M-15的N-和C-末端部分和CTX-M-14的中间片段的CTX-M-64显示出比其亲本原型更高的催化活性(He <等)。,2015)。

DNA改组是一种分子途径,被设计为通过PCR介导的两种靶基因的随机组合来模拟和加速进化过程(Crameri ...

3D Culture Protocol for Testing Gene Knockdown Efficiency and Cell Line Derivation
Author:
Date:
2018-06-05
[Abstract]  Traditional 2D cell cultures with cells grown as monolayers on solid surface still represent the standard method in cancer research for drug testing. Cells grown in 2D cultures, however, lack relevant cell-matrix and cell-cell interactions and ignore the true three-dimensional anatomy of solid tumors. Cells cultured in 2D can also undergo cytoskeletal rearrangements and acquire artificial polarity associated with aberrant gene expression (Edmondson et al., 2014). 3D culture systems that better mimic the in vivo situation have been developed recently. 3D in vitro cancer models (tumorspheres) for studying cancer stem cells have gained increased popularity in the field (Weiswald et al., 2015). Systems that use matrix-embedded or encapsulated spheroids, ... [摘要]  细胞在固体表面生长为单层的传统二维细胞培养仍然代表了药物检测癌症研究的标准方法。然而,在2D培养物中生长的细胞缺乏相关的细胞基质和细胞 - 细胞相互作用,并且忽略实体肿瘤的真实三维解剖结构。在2D中培养的细胞也可经历细胞骨架重排并获得与异常基因表达相关的人造极性(Edmondson等人,2014)。最近开发出更好地模拟体内情况的3D文化系统。用于研究癌症干细胞的3D体外肿瘤模型(肿瘤球体)在该领域已经获得了越来越多的普及(Weiswald等人,2015)。使用基质嵌入或封装的球体,悬滴培养的球体,磁悬浮系统或3D打印方法的系统已经广泛用于研究和新药筛选。在本文中,我们描述了测试shRNA介导的基因沉默对肿瘤球体形成和生长的影响的详细方案。这种方法允许研究人员测试基因敲低对肿瘤起始细胞生长的影响。正如我们实验室所证实的那样,该方案也可用于直接从肿瘤组织中分离3D癌细胞系。

【背景】3D体外肿瘤细胞模型代表了细胞系与体内生长的肿瘤之间的桥接实验方法(Pampaloni等人,2007; ...

Generating Loss-of-function iPSC Lines with Combined CRISPR Indel Formation and Reprogramming from Human Fibroblasts
Author:
Date:
2018-04-05
[Abstract]  For both disease and basic science research, loss-of-function (LOF) mutations are vitally important. Herein, we provide a simple stream-lined protocol for generating LOF iPSC lines that circumvents the technical challenges of traditional gene-editing and cloning of established iPSC lines by combining the introduction of the CRISPR vector concurrently with episomal reprogramming plasmids into fibroblasts. Our experiments have produced nearly even numbers of all 3 genotypes in autosomal genes. In addition, we provide a detailed approach for maintaining and genotyping 96-well plates of iPSC clones. [摘要]  对于疾病和基础科学研究而言,功能丧失(LOF)突变是非常重要的。 在这里,我们提供了一个简单的流线化协议来产生LOF iPSC系列,通过将CRISPR载体与附加型重编程质粒同时引入成纤维细胞,规避了传统基因编辑和已建立的iPSC系的克隆的技术挑战。 我们的实验已经产生了常染色体基因中所有3种基因型的几乎偶数。 此外,我们提供了一个详细的方法来维护和iPSC克隆的96孔板的基因分型。

【背景】CRISPR / Cas9技术允许简单且特异地针对特定基因组位置进行基因编辑。将该技术与诱导性多能干细胞(iPSC)的疾病建模和再生医学潜力相结合将继续对生物医学研究产生前所未有的影响。然而,使CRISPR / Cas9系统适应iPSC已经提出了几个挑战。在细胞系中进行基因编辑的传统方法是用表达Cas9蛋白质的质粒和指导RNA(gRNA)转染细胞,然后产生单克隆并筛选所需的遗传改变。不幸的是,iPSC不适用于单细胞克隆。已经开发了几种补充媒介和克隆方法来克服这一困难,但仍然充满昂贵的设备(低氧培养箱),困难的技术步骤(FACS分选的单个iPSC的存活)或劳动密集型方案(亚克隆)(Forsyth ,2006; Miyaoka ...

Comments