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首页> 外文期刊>Applied Microbiology >Comparative Analysis of Antimicrobial Activities of Valinomycin and Cereulide, the Bacillus cereus Emetic Toxin
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Comparative Analysis of Antimicrobial Activities of Valinomycin and Cereulide, the Bacillus cereus Emetic Toxin

机译：蜡状芽孢杆菌催吐毒素Valinomycin和Cereulide抗菌活性的比较分析

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Cereulide and valinomycin are highly similar cyclic dodecadepsipeptides with potassium ionophoric properties. Cereulide, produced by members of the Bacillus cereus group, is known mostly as emetic toxin, and no ecological function has been assigned. A comparative analysis of the antimicrobial activity of valinomycin produced by Streptomyces spp. and cereulide was performed at a pH range of pH 5.5 to pH 9.5, under anaerobic and aerobic conditions. Both compounds display pH-dependent activity against selected Gram-positive bacteria, including Staphylococcus aureus , Listeria innocua , Listeria monocytogenes , Bacillus subtilis , and Bacillus cereus ATCC 10987. Notably, B. cereus strain ATCC 14579 and the emetic B. cereus strains F4810/72 and A529 showed reduced sensitivity to both compounds, with the latter two strains displaying full resistance to cereulide. Both compounds showed no activity against the selected Gram-negative bacteria. Antimicrobial activity against Gram-positive bacteria was highest at alkaline pH values, where the membrane potential (ΔΨ) is the main component of the proton motive force (PMF). Furthermore, inhibition of growth was observed in both aerobic and anaerobic conditions. Determination of the ΔΨ, using the membrane potential probe DiOC_(2)(3) (in the presence of 50 mM KCl) in combination with flow cytometry, demonstrated for the first time the ability of cereulide to dissipate the ΔΨ in sensitive Gram-positive bacteria. The putative role of cereulide production in the ecology of emetic B. cereus is discussed.
机译：鲸蜡内酯和缬霉素是具有钾离子载体性质的高度相似的环状十二肽。蜡状芽孢杆菌属成员产生的蜡状内酯主要被称为催吐毒素，尚未赋予生态功能。链霉菌属（Streptomyces spp）产生的缬氨霉素的抗菌活性的比较分析。蜡菊酯在pH 5.5至pH 9.5的范围内，在厌氧和好氧条件下进行。两种化合物均对选定的革兰氏阳性细菌（包括金黄色葡萄球菌，无毒李斯特菌，单核细胞增生李斯特菌，枯草芽孢杆菌和蜡状芽孢杆菌ATCC 10987）表现出pH依赖性活性。值得注意的是，蜡状芽孢杆菌ATCC 14579菌株和蜡状芽孢杆菌F4810 / 72和A529对这两种化合物均显示出降低的敏感性，后两种菌株显示出对蜡菊酯的完全抗性。两种化合物均对所选革兰氏阴性细菌没有活性。在碱性pH值下，革兰氏阳性菌的抗菌活性最高，其中膜电势（ΔΨ）是质子动力（PMF）的主要成分。此外，在有氧和厌氧条件下均观察到生长抑制。与膜电势探针DiOC_（2）（3）（在50 mM KCl存在下）结合流式细胞仪测定ΔΨ，首次证明了蜡样内酯消散ΔΨ在敏感的革兰氏阳性菌中的能力。菌。讨论了蜡样内酯生产在催吐芽孢杆菌生态学中的假定作用。

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