Institute of Food Safety, Wageningen University, The Netherlands.
Lett Appl Microbiol. 2012 Jan;54(1):52-8. doi: 10.1111/j.1472-765X.2011.03170.x. Epub 2011 Nov 21.
To elucidate the molecular mechanism of action of the antimicrobial peptide subtilosin against the foodborne pathogen Listeria monocytogenes Scott A.
Subtilosin was purified from a culture of Bacillus amyloliquefaciens. The minimal inhibitory concentration of subtilosin against L. monocytogenes Scott A was determined by broth microdilution method. The effect of subtilosin on the transmembrane electrical potential (ΔΨ) and pH gradient (ΔpH), and its ability to induce efflux of intracellular ATP, was investigated. Subtilosin fully inhibited L. monocytogenes growth at a concentration of 19 μg ml(-1) . Subtilosin caused a partial depletion of the ΔΨ and had a similar minor effect on the ΔpH. There was no significant efflux of intracellular ATP.
Subtilosin likely acts upon L. monocytogenes Scott A by perturbing the lipid bilayer of the cellular membrane and causing intracellular damage, leading to eventual cell death. Subtilosin's mode of action against L. monocytogenes Scott A differs from the one previously described for another human pathogen, Gardnerella vaginalis.
This is the first report on the specific mode of action of subtilosin against L. monocytogenes and the first report of a bacteriocin with a species-specific mode of action.
阐明抗菌肽枯草菌素对食源性病原体单核细胞增生李斯特菌的作用机制。
枯草菌素从解淀粉芽孢杆菌的培养物中纯化得到。采用肉汤微量稀释法测定枯草菌素对单核细胞增生李斯特菌斯科特 A 的最小抑菌浓度。研究了枯草菌素对跨膜电势（ΔΨ）和 pH 梯度（ΔpH）的影响，以及其诱导细胞内 ATP 外排的能力。枯草菌素在 19μg ml(-1)的浓度下完全抑制单核细胞增生李斯特菌的生长。枯草菌素导致 ΔΨ部分耗竭，并对 ΔpH 产生类似的轻微影响。细胞内 ATP 无明显外排。
枯草菌素可能通过扰乱细胞膜的脂质双层并导致细胞内损伤，从而导致最终的细胞死亡，从而作用于单核细胞增生李斯特菌斯科特 A。枯草菌素对单核细胞增生李斯特菌斯科特 A 的作用模式与先前描述的另一种人类病原体阴道加德纳菌的作用模式不同。
这是枯草菌素对单核细胞增生李斯特菌的特定作用模式的首次报道，也是具有种特异性作用模式的细菌素的首次报道。
