首页|Controlling Listeria monocytogenes in ready-to-eat leafy greens by amphipathic alpha-helix peptide zp80 and its antimicrobial mechanisms

Controlling Listeria monocytogenes in ready-to-eat leafy greens by amphipathic alpha-helix peptide zp80 and its antimicrobial mechanisms

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Pathogens can stick to the surfaces of leaves and ready-to-eat leafy greens are usually eaten without any lethal treatment to remove them. In this study, the peptide zp80 was chemically synthesized and purified. It had alpha-helix structure by circular dichroism spectroscopy analysis. zp80 reduced aerobic bacteria in ready-to-eat vegetable salad and lettuce. zp80 had MIC values of 2-8 mu M against 7 foodborne pathogens, it was 2 mu M to Listeria monocytogenes. Growth curve and time-kill curve showed that zp80 exhibited bactericidal mode with partial cell lysis. Confocal microscope indicated that zp80 was able to penetrate inside the cell membrane and distributed in cytoplasm and nucleus. Cell deformation with sunken surface was observed using scanning electron microscope. Further, results of SYTOX green and DiSC3(5) showed that zp80 had membrane depolarization caused by pore formation. After entering cytoplasm of L. monocytogenes, zp80 could bind to DNA, and then precipitated DNA. In addition, zp80 induced the production of intracellular reactive oxygen species (ROS), which played a key role on lethal effect by analysis using SYTO9 and PI. Hurdling treatment with 64 mu M zp80 reduced 4.18 log units of L. monocytogenes in fresh-cut lettuce and alleviated browning after 7-day storage.

Ready-to-eat leafy greensAntimicrobial peptideCell membraneDNA bindingROS

Yi, Lanhua、Zeng, Ping、Wong, Kwok-Yin、Chan, Kin-Fai、Chen, Sheng

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Southwest Univ, Coll Food Sci, Chongqing 400715, Peoples R China

Hong Kong Polytech Univ, State Key Lab Chem Biol & Drug Discovery, Kowloon, Hong Kong, Peoples R China

City Univ Hong Kong, Dept Infect Dis & Publ Hlth, Jockey Club Coll Vet Med & Life Sci, Kowloon, Hong Kong, Peoples R China

2021

LWT-Food Science & Technology

LWT-Food Science & Technology

ISSN:0023-6438
年,卷(期):2021.152
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