Our previous work demonstrated that two commonly used fluorescent dyes that were accumulated by wild-type Escherichia coli MG1655 were differentially transported in single-gene knockout strains, and also that they might be used as surrogates in flow cytometric transporter assays. We summarize the desirable properties of such stains, and here survey 143 candidate dyes. We eventually triage them (on the basis of signal, accumulation levels and cost) to a palette of 39 commercially available and affordable fluorophores that are accumulated significantly by wild-type cells of the 'Keio' strain BW25113, as measured flow cytometrically. Cheminformatic analyses indicate both their similarities and their (much more considerable) structural differences. We describe the effects of pH and of the efflux pump inhibitor chlorpromazine on the accumulation of the dyes. Even the 'wild-type' MG1655 and BW25113 strains can differ significantly in their ability to take up such dyes. We illustrate the highly differential uptake of our dyes into strains with particular lesions in, or overexpressed levels of, three particular transporters or transporter components (yhjV, yihN and tolC). The relatively small collection of dyes described offers a rapid, inexpensive, convenient and informative approach to the assessment of microbial physiology and phenotyping of membrane transporter function.

中文翻译：

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由大肠杆菌的野生型和突变株差异积累的一组荧光团：用于分析细菌膜转运蛋白的替代配体

我们之前的工作表明，野生型大肠杆菌 MG1655 积累的两种常用荧光染料在单基因敲除菌株中被差异转运，并且它们也可能用作流式细胞仪转运蛋白检测的替代物。我们总结了此类污渍的理想特性，并在此调查了 143 种候选染料。我们最终将它们（根据信号、积累水平和成本）分类为 39 种市售且负担得起的荧光团，这些荧光团由“Keio”菌株 BW25113 的野生型细胞显着积累，如流式细胞仪测量。化学信息学分析表明它们的相似性和（更重要的）结构差异。我们描述了 pH 值和外排泵抑制剂氯丙嗪对染料积累的影响。即使是“野生型”MG1655 和 BW25113 菌株在吸收此类染料的能力方面也存在显着差异。我们说明了我们的染料在三种特定转运蛋白或转运蛋白组分（yhjV、yihN 和 tolC）中具有特定病变或过度表达水平的菌株的高度差异吸收。所描述的相对较少的染料集合为微生物生理学和膜转运蛋白功能的表型评估提供了一种快速、廉价、方便和信息丰富的方法。我们说明了我们的染料在三种特定转运蛋白或转运蛋白组分（yhjV、yihN 和 tolC）中具有特定病变或过度表达水平的菌株的高度差异吸收。所描述的相对较少的染料集合为微生物生理学和膜转运蛋白功能的表型评估提供了一种快速、廉价、方便和信息丰富的方法。我们说明了我们的染料在三种特定转运蛋白或转运蛋白组分（yhjV、yihN 和 tolC）中具有特定病变或过度表达水平的菌株的高度差异吸收。所描述的相对较少的染料集合为微生物生理学和膜转运蛋白功能的表型评估提供了一种快速、廉价、方便和信息丰富的方法。