College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, Jiangsu Province, PR China; Department of Chemical Engineering, Guangdong Technion-Israel Institute of Technology (GTIIT), Shantou, Guangdong 515063, PR China; Department of Food Science & Technology, Ebonyi State University, EBSU, PMB 053, Abakaliki, Ebonyi State, Nigeria.
College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, Jiangsu Province, PR China.
Int J Food Microbiol. 2022 Dec 16;383:109953. doi: 10.1016/j.ijfoodmicro.2022.109953. Epub 2022 Sep 29.
Transcriptomic analysis was used to investigate the antibacterial mechanism of phenolic compounds from kefir fermented soy whey (FSP) against Escherichia coli 0157:H7 and Listeria monocytogenes. The kefir fermentation increased the concentration of several phenolic aglycones with proven antibacterial efficacy in the FSP. The time-kill curve showed that 2× MICs of the FSP killed >99.9 % of the strains within 2 h of exposure. The checkerboard fractional inhibition concentration (FIC) assay proved that phenolics were the sole antibacterial agent in the FSP. The transmission electron microscope (TEM) photomicrograph corroborated the propidium iodide (PI) uptake, protein, and nucleic acid leakage assays. They demonstrated that the phenolics permeated the cell membrane, disrupted the cytoplasm, and caused cell lysis in the treated cells leading to protein and nucleic acid leakage. The transcriptome analysis revealed that exposure of the cells to MICs of the phenolics induced molecular responses leading to differential expression of 1850 genes in E. coli 0157:H7 and 2090 in L. monocytogenes. The phenolics suppressed the expression of genes crucial for carbohydrate utilization, transmembrane glucose transport, tricarboxylic acid (TCA), and ATP synthesis. The phenolic-induced stress also downregulated the expression of quorum sensing and virulence-related genes, peptidoglycan and phospholipid synthases, and ABC transporters. The cells initiated a resistance response by stimulating the two-component signal transduction systems to trigger the over-expression of a cascade of genes involved in stress resistance, gluconeogenesis, ATPase activity and proton transmembrane transport. Nonetheless, the data indicated that the phenolics suppressed the expression of translational proteins that would have facilitated the resistance and repair of the cell damage caused by the phenolics. The study provides discrete data evidence that FSP could be used to control the pathogenicity and the proliferation of E. coli 0157:H7 and L. monocytogenes in our foods and food systems.
采用转录组学分析方法研究了开菲尔发酵大豆乳清（FSP）中酚类化合物对大肠杆菌 0157:H7 和单核细胞增生李斯特菌的抗菌机制。开菲尔发酵增加了 FSP 中几种具有已证明抗菌功效的酚糖苷配基的浓度。时间杀伤曲线表明，FSP 的 2×MIC 在暴露 2 小时内杀死了 >99.9%的菌株。棋盘微量稀释法（FIC）测定证实酚类化合物是 FSP 中唯一的抗菌剂。透射电子显微镜（TEM）照片证实了碘化丙啶（PI）摄取、蛋白质和核酸渗漏测定。它们表明酚类化合物穿透细胞膜，破坏细胞质，并导致处理细胞裂解，导致蛋白质和核酸渗漏。转录组分析表明，细胞暴露于 MIC 酚类化合物会诱导分子反应，导致大肠杆菌 0157:H7 中 1850 个基因和单核细胞增生李斯特菌中 2090 个基因的差异表达。酚类化合物抑制了碳水化合物利用、跨膜葡萄糖转运、三羧酸（TCA）和 ATP 合成所需的关键基因的表达。酚类诱导的应激还下调了群体感应和毒力相关基因、肽聚糖和磷脂合成酶以及 ABC 转运蛋白的表达。细胞通过刺激双组分信号转导系统来启动抗性反应，触发与应激抗性、糖异生、ATP 酶活性和质子跨膜转运相关的一系列基因的过表达。尽管如此，数据表明酚类化合物抑制了翻译蛋白的表达，这将有助于细胞对酚类化合物引起的损伤进行抗性和修复。该研究提供了离散的数据证据，表明 FSP 可用于控制食品和食品系统中大肠杆菌 0157:H7 和单核细胞增生李斯特菌的致病性和增殖。
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