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Company: Merck
Catalog#: M7506
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A One-enzyme RT-qPCR Assay for SARS-CoV-2, and Procedures for Reagent Production
Author:
Date:
2021-01-20
[Abstract]  

Given the scale of the ongoing COVID-19 pandemic, the need for reliable, scalable testing, and the likelihood of reagent shortages, especially in resource-poor settings, we have developed an RT-qPCR assay that relies on an alternative to conventional viral reverse transcriptases, a thermostable reverse transcriptase/DNA polymerase (RTX) (Ellefson et al., 2016). Here we show that RTX performs comparably to the other assays sanctioned by the CDC and validated in kit format. We demonstrate two modes of RTX use – (i) dye-based RT-qPCR assays that require only RTX polymerase, and (ii) TaqMan RT-qPCR assays that use a combination of RTX and Taq DNA polymerases (as the RTX exonuclease does not degrade a TaqMan probe). We also provide straightforward recipes for the purification of this

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[摘要]  [摘要]鉴于持续进行的COVID-19大流行的规模,可靠,可扩展的测试需求以及试剂短缺的可能性(尤其是在资源匮乏的环境中),我们开发了一种n RT-qPCR分析方法,该方法依赖于其他方法与常规病毒逆转录酶相比,热稳定的逆转录酶/ DNA聚合酶(RTX)(Ellefson等,2016)。在这里,我们显示RTX与CDC认可并以试剂盒形式验证的其他检测方法具有可比性。我们演示了两种RTX使用模式-(i)仅需要RTX聚合酶的基于染料的RT-qPCR分析,以及(ii)使用RTX和Taq DNA聚合酶组合的TaqMan RT-qPCR分析(因为RTX核酸外切酶不降级ea TaqMan探针)。我们还提供了纯化该替代试剂RTX的简单方法。我们预计,在资源匮乏或需要的地方,研究人员可以获取可用的构建体,并开始开发自己的测定方法,而不论它们存在的调控框架如何。


[背景]尽管已采用多种病毒检测方法来检测SARS-CoV-2感染,包括各种分子诊断和免疫诊断测试,但逆转录酶定量聚合酶链反应(RT-qPCR)仍然是主要且最敏感的方法SARS-CoV-2检测试验(D'Cruz等,2020 ; Tang等,2020 )。RT-qPCR的首要地位在很大程度上是因为基于抗体的测试以及快速核酸诊断平台(如Abbott ...

Preparation of Bacterial Outer Membrane Vesicles for Characterisation of Periplasmic Proteins in Their Native Environment
Author:
Date:
2020-12-20
[Abstract]  

Bacterial outer membrane vesicles (OMVs) are naturally formed by budding from the outer membrane of Gram-negative bacteria. OMVs consist of a lipid bilayer identical in composition to the original outer membrane and contain periplasmic content within their lumen. Enriched with specific envelope proteins, OMVs make for an excellent native-like platform to study these proteins in-situ using biophysical methods. Here, we describe in detail the preparation of OMVs from Escherichia coli, which are luminally enriched with periplasmic proteins and uniformly labeled with stable isotopes (2H and 15N), suitable for the subsequent characterisation of proteins at atomic resolution in their native environment by solution-state NMR spectroscopy. The ability to perform structural studies of periplasmic

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[摘要]  [摘要]细菌外膜囊泡(OMV)是由革兰氏阴性细菌的外膜出芽自然形成的。OMV由组成与原始外膜相同的脂质双层组成,并且在其内腔中含有周质成分。OMV富含特定的包膜蛋白,是使用生物物理方法原位研究这些蛋白的绝佳天然样平台。在这里,我们详细描述了从大肠杆菌制备OMV的方法,该方法在光亮时富含周质蛋白,并用稳定的同位素(2 H和15 N)均匀标记,适用于后续表征溶液状态NMR光谱分析天然环境中蛋白质的原子分辨率。执行周质成分的结构研究的能力,现场清除的方式来REAC兴的这种独特的细胞室的功能和机理细节的深入了解。

[背景]革兰氏阴性菌的周质是一个相当了不起的细胞室。这个空间中,内和外细菌膜之间禁闭,包含在抽蛋白一个ö ř dinarily高浓度超过300毫克毫升-1 (奥利弗,1996) ,并且在不存在的细胞来源,如ATP,功能几乎大力独立从其胞质对应物。到目前为止,有关周质蛋白的结构知识是使用从其天然环境分离的纯化蛋白专门获得的。因此,这种特殊环境可能对蛋白质施加的任何结构和功能影响在纯化过程中都会丢失。由于周质的体积比低,阻碍了使用生物物理方法如细胞内NMR光谱原位研究周质蛋白的努力,周质的体积比仅占细菌总体积的5-1 0%(Brass等,1986)。 )。

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Rapid Isolation and Purification of Secreted Bacteriocins from Streptococcus mutans and Other Lactic Acid Bacteria
Author:
Date:
2020-11-20
[Abstract]   Bacteriocins are small ribosomally synthesized antimicrobial peptides produced by some microorganisms including lactic acid bacteria (LAB), a group of Gram-positive bacteria (cocci, rods) expressing high tolerance for low pH. Bacteriocins kill bacteria rapidly and are biologically active at very low concentrations. Bacteriocins produced by LAB are primarily active against closely related bacterial species. Many bacteriocins have been investigated with respect to their potential use in promoting human, plant, and animal health, and as food biopreservatives. Bacteriocins produced by LAB are particularly interesting since several LAB have been granted GRAS (Generally Recognized as Safe) status. Because it is not always possible to extract active bacteriocins secreted from cells grown in ... [摘要]  [摘要]细菌素是由一些核糖体合成的抗菌肽微生物,包括乳酸菌(LAB),一组革兰氏阳性菌(球菌,棒)表现出对低pH的高耐受性。细菌素可迅速杀死细菌,并在极高的温度下具有生物活性。低浓度。LAB生产的细菌素主要对紧密相关的细菌具有活性种类。已经研究了许多细菌素在促进细菌生长方面的潜在用途。对人类,植物和动物健康,以及作为食品生物防腐剂。LAB生产的细菌素是特别有趣的是,由于一些实验室已获得GRAS(通常被认为是安全的)状态。因为并非总是可能提取液体中生长的细胞分泌的活性细菌素介质,我们开发了一种使用半固体的简单而廉价的肽提取程序营养丰富的琼脂培养基。我们在此提出一种详细的程序,以快速提取出从口腔物种分泌的生物活性细菌素肽变异链球菌,多产的菌种的生产及其在其他实验室提取细菌素的潜在应用(例如,链球菌,乳球菌,肠球菌)。我们还提出了一种简单的检测方法纯化的细胞外肽提取物的细菌素活性测定

[背景]自然界中的大多数细菌并不是独立存在,而是存在于复杂的多物种中生物膜群落(López等,2010)。两者之间存在大量的身体和营养相互作用细菌有助于生物膜的生长和存活。细菌素的产生和分泌细胞外空间为生产者与其他竞争者赋予了独特的生态优势存在于同一生态位中的细菌(Donia and ...

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