摘要
To reveal the antimicrobial mechanism of metal antimicrobial peptide (MAP) SIF4 against Escherichia coli based on glucose metabolism pathway and cytoplasmic membrane oxidative damage, the effects of SIF4 on critical enzymatic activity of Embden-Meyerhof-Parnas (EMP) pathway and tricarboxylic acid (TCA) cycle, cytoplasmic membrane oxidative damage, intracellular ROS production and cell membrane depolarization were investigated. Results showed that, SIF4 inhibited the key enzymes in glycolysis, including hexokinase (HK), phosphofructokinase (PFK) and pyruvate kinase (PK), by 66. 61%, 27. 37, and 39. 61%, respectively, and the key enzymes in TCA cycle, including pyruvate dehydrogenase complex (PDHC), citrate synthetase (CS), isocitrate dehydrogenase (IDH) and α-ketoglutaric dehydrogenase (α-KGDH), by 25. 20%, 22. 91%, 26. 99 and 23. 44%, respectively. SIF4 exerted good antimicrobial capacity mainly through regulating glucose oxidation efficiency by restraining the HK activity in glycolysis. It was also confirmed that SIF4 could cause cytoplasmic membrane oxidative damage and induce oxidative stress to produce excessive ROS, resulting in destroying cytoplasmic membrane structural integrity, and exerting synergistic enhancement of antimicrobial capacity by inducing cell apoptosis or programmed cell death. All results can provide direct evidence for systematically elucidating antimicrobial mechanism of SIF4 against E. coli, and also offer theoretical support for its application in the biological control of foodborne E. coli. ? 2022 Food and Fermentation Industries.
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