Abstract

Antimicrobial peptides (AMPs) are recognized as promising safe alternatives to antibiotics for its low drug-resistance. Brevilaterin B, a newly discovered antimicrobial lipopeptide produced by Brevibacillus laterosporus S62-9, exhibits efficient antibacterial activity on Listeria monocytogenes with a minimum inhibitory concentration of 1 μg mL⁻¹. The present research aimed to investigate the antibacterial mechanism of brevilaterin B against Listeria monocytogenes. Brevilaterin B caused membrane depolarization and the breakup of the cytomembrane as measured by 3,3-dipropylthiadicarbocyanine iodide and transmission electron microscopy, respectively. Using 1,2-dipalmitoyl-sn-glycero-3-phosphocholine and 1,2-dipalmitoyl-sn-glycero-3-phospho-rac-(1-glycerol) sodium salt (7:3) as a model membrane, results proved that brevilaterin B could bind to liposomes, integrate into the lipid bilayer, and consequently increase the permeability of liposomes to calcein. The secondary structure of brevilaterin B also changed from an unstructured coil to a mainly β-sheet conformation as measured by circular dichroism. Brevilaterin B exhibits antibacterial activity by a membrane interaction mechanism, which provides a theoretical basis for using brevilaterin B as a promising natural and effective antimicrobial agent against pathogenic bacteria.

Key points

• Brevilaterin B exhibited antibacterial activity against Listeria monocytogenes.

• Brevilaterin B exhibited membrane interaction mechanism.

• Brevilaterin B showed conformational change when interacted with liposome.

中文翻译：

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brevilaterin B的抗菌机制：靶向李斯特菌李斯特菌膜的两亲脂肽

摘要

抗菌肽（AMPs）因其低耐药性而被认为是有前途的安全替代抗生素。Brevilaterin B是一种新发现的由枯草芽孢杆菌S62-9产生的抗菌脂肽，对单核细胞增生性李斯特菌具有有效的抗菌活性，最低抑菌浓度为1μgmL ^-1。本研究旨在探讨brevilaterin B对单核细胞增生李斯特菌的抗菌机制。如分别通过3,3-二丙基噻二碳杂菁花青碘化物和透射电镜观察到的那样，芥子酸酯B引起膜去极化和细胞膜破裂。使用1,2-二棕榈酰-sn-甘油-3-磷酸胆碱和1,2-二棕榈酰-sn-甘油-3-磷酸-rac-（1-甘油）钠盐（7：3）作为模型膜，结果证明brevilaterin B可以与脂质体结合，整合到脂质双层中，从而增加脂质体对钙黄绿素的渗透性。brevilaterin B的二级结构也从无结构的线圈变为主要由β-片状构象，如通过圆二色性所测。芥末素B通过膜相互作用机制表现出抗菌活性，

关键点

•短乙藻酸酯B对单核细胞增生李斯特菌具有抗菌活性。

•芥子酸酯B表现出膜相互作用机制。

•芥子油素B与脂质体相互作用时显示构象变化。