Valinomycin

伏立诺霉素

Company: Sigma-Aldrich

Catalog#: 94675

Determination of Poly(3-hydroxybutyrate) Content in Cyanobacterium Synechocystis sp. PCC 6803 Using Acid Hydrolysis Followed by High-performance Liquid Chromatography

Janine Kaewbai-ngam, Aran Incharoensakdi and Tanakarn Monshupanee

Published online: 2023-08-20

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Measurement of the Electrogenicity of Bile Salt/H⁺ Antiport in Escherichia coli

Author:

Scarlett R. Holdsworth and Christopher J. Law,

Date:

2014-11-05

[Abstract] The transmembrane proton gradient (ΔpH) is the primary source of energy exploited by secondary active substrate/H⁺ antiporters to drive the electroneutral transport of substrates across the Escherichia coli (E. coli) inner membrane. Such electroneutral transport results in no net movement of charges across the membrane. The charge on the transported substrate and the stoichiometry of the exchange reaction, however, can result in an electrogenic reaction which is driven by both the ΔpH and the electrical (∆Ψ) components of the proton electrochemical gradient, resulting in a net movement of electrical charges across the membrane. We have shown that the major facilitator superfamily transporter MdtM - a multidrug efflux protein from E. coli that ... [摘要] 跨膜质子梯度（ΔpH）是由次级活性底物/H sup +反转录子开发的能量的主要来源，以驱动底物穿过大肠杆菌的电中性转运（ >大肠杆菌）内膜。这种电中性转运导致电荷没有跨膜的净移动。然而，运输的底物上的电荷和交换反应的化学计量可以导致由ΔpH和质子电化学梯度的电（ΔΨ）分量驱动的电致反应，导致电移动的净移动电荷穿过膜。我们已经显示主要促进子超家族转运蛋白MdtM-来自E的多药物外排蛋白。在保护细菌细胞对抗胆汁盐中起到生理作用的大肠杆菌通过偶联外部质子（H + +）与胆汁盐的外流的交换而赋予细菌细胞对胆汁盐的抗性通过电致反应反应的细胞内部（Paul et al。，2014）。该协议使用荧光测定法描述了如何检测Ed的逆转子缺陷菌株的倒置膜囊泡中MdtM的电致逆转运蛋白活性。通过测量跨膜ΔΨ测定大肠杆菌 TO114细胞。该方法利用响应于由于MdtM催化的胆酸钠/H +交换反应引起的膜电位变化而发生在探针Oxonol V的荧光信号强度（淬灭和去淬灭）中发生的变化。该方案可以适于检测任何辅助活性反转运蛋白的活性，其将H sup +跨越生物膜的电致易位与其对应底物的电转运偶联，并且可以用于解偶联否则伪装的转运活性和生理作用。

Cytotoxicity Assay for Detection of Cereulide Produced by Emetic Bacillus cereus

Author:

Elrike Frenzel and Monika Ehling-Schulz,

Date:

2013-01-20

[Abstract] The emetic subgroup of Bacillus cereus strains produces cereulide, a dodecadepsipeptide (1.2 kDa), which is the causative agent of food poisonings. Cereulide is synthesized by a nonribosomal peptide synthetase (NRPS), the Ces-NRPS (Ehling-Schulz et al., 2006). Cereulide is a cyclic and lipophilic potassium ionophor structurally related to the macrolide antibiotic valinomycin. Both substances act on mitochondria by depolarization and uncoupling of ATP synthesis, and this effect (mitochondrial swelling) is used to quantify cereulide in a HEp-2 cell based viability assay.

In this protocol, which was modified from an assay published by Finlay et al. (1999), valinomycin is used as a reference standard for ionophor–induced cytotoxicity, because purified ... [摘要] 蜡状芽孢杆菌菌株的催吐亚组产生作为食物中毒的致病因子的十二缩酚酸肽（1.2kDa）的cereulide。谷胱甘肽通过非核糖体肽合成酶（NRPS），Ces-NRPS（Ehling-Schulz等人，2006）合成。脑苷脂是与大环内酯类抗生素缬氨霉素结构相关的环状和亲脂性钾离子体。这两种物质通过ATP合成的去极化和解偶联作用于线粒体，并且该效应（线粒体肿胀）用于在基于HEp-2细胞的活力测定中量化脑苷脂。
在该方案中，根据Finlay等人（1999）发表的试验进行了修改，缬氨霉素被用作离子体诱导的细胞毒性的参考标准，因为纯化的脑苷脂不是商业上的可用。该测定法已经用于定量来自不同B的脑梗的量。 cereus突变体（Lücking等人，2009; Frenzel等人，2012），并且估计从人类（人工）污染的食物中提取的脑苷脂水平> B。 cereus （Frenzel ，2011）。

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Valinomycin

伏立诺霉素

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