Han J, Zhao S, Ma Z, Gao L, Liu H, Muhammad U, Lu Z, Lv F, Bie X
Key Laboratory of Food Processing and Quality Control, College of Food Science and Technology, Nanjing Agricultural University, Ministry of Agriculture of China, Nanjing, China.
J Appl Microbiol. 2017 Sep;123(3):602-614. doi: 10.1111/jam.13526.
LI-Fs are a family of highly potent cyclic lipodepsipeptide antibiotics with a broad antimicrobial spectrum (Gram-positive bacteria and fungi). In this study, LI-F-type antimicrobial peptides (AMP-jsa9) composing of LI-F03a, LI-F03b, LI-F04a, LI-F04b and LI-F05b were isolated from Paenibacillus polymyxa JSA-9. To better understand the antimicrobial mechanism of AMP-jsa9, the potency and action(s) of AMP-jsa9 against Bacillus cereus were examined.
Flow cytometry, confocal laser microscopy, scanning electron microscopy, transmission electron microscopy (TEM) and atomic force microscopy observation, as well as determination of peptidoglycan and cell wall-associated protein and other methods were used. The results indicate that AMP-jsa9 exhibits strong, broad-spectrum antimicrobial activity. Moreover, AMP-jsa9 targets the cell wall and membrane of B. cereus to impair membrane integrity, increase membrane permeability and enhance cytoplasm leakage (e.g. K , protein, nucleic acid). This leads to bacterial cells with irregular, withered and coarse surfaces. In addition, AMP-jsa9 is also able to bind to DNA and break down B. cereus biofilms.
In this study, the action mechanism of LI-Fs against B. cereus was clarified in details.
The results of this study provide a theoretical basis for utilizing AMP-jsa9 or similar analogues as natural and effective preservatives in the food and feed industries. These efforts could also stimulate research activities interested in understanding the specific effects of other antimicrobial agents.
脂肽（LI-Fs）是一类具有广谱抗菌活性（针对革兰氏阳性菌和真菌）的高效环脂肽抗生素。在本研究中，从多粘芽孢杆菌JSA-9中分离出由LI-F03a、LI-F03b、LI-F04a、LI-F04b和LI-F05b组成的LI-F型抗菌肽（AMP-jsa9）。为了更好地理解AMP-jsa9的抗菌机制，检测了AMP-jsa9对蜡样芽孢杆菌的效力和作用。
采用流式细胞术、共聚焦激光显微镜、扫描电子显微镜、透射电子显微镜（TEM）和原子力显微镜观察，以及肽聚糖、细胞壁相关蛋白的测定等方法。结果表明，AMP-jsa9具有强大的广谱抗菌活性。此外，AMP-jsa9作用于蜡样芽孢杆菌的细胞壁和细胞膜，损害膜完整性，增加膜通透性，增强细胞质泄漏（如钾离子、蛋白质、核酸）。这导致细菌细胞表面不规则、枯萎且粗糙。此外，AMP-jsa9还能够结合DNA并破坏蜡样芽孢杆菌生物膜。
本研究详细阐明了脂肽对蜡样芽孢杆菌的作用机制。
本研究结果为在食品和饲料工业中利用AMP-jsa9或类似类似物作为天然有效防腐剂提供了理论依据。这些努力还可能激发对理解其他抗菌剂具体作用感兴趣的研究活动。
